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You are an expert at summarizing long articles. Proceed to summarize the following text: MINING MACHINE WITH RELEASABLE GUIDE PIECE AND THE GUIDE PIECE FOR IT The invention relates to a mining machine for underground mining, more specifically to a winning or coal plough, which mining machine is guided along a machine guide that includes a guide rail. The invention also relates to a guide piece that slides on or along the guide rail. A generic mining machine, configured as an extraction plough, is known from DE 37 11 105 A1. The plough described therein has an upper guide pawl that engages the guide rail from above. A guide piece, provided between the guide pawl of the plough and the guide rail, is attached to the guide pawl and slides on or against the fixed guide rail when the plough is being operated. Since the guide piece is exposed to extreme strain it is subjected to a high rate of wear. It is therefore detachably attached to the guide pawl so that it can be exchanged regularly. The U-shaped guide piece is configured with two limbs, set apart from one another. The guide piece on one base and on a transverse web that connects the limbs thereof is provided with bores through which bolts engage via which the exchangeable guide piece can be attached to the guide pawl of the plough body. If, in the course of an exchange, a new guide piece is to be attached to the guide pawl, the guide piece must be held in a corresponding position until the joint with the guide pawl has been effected. Only then does the guide pawl hold the weight of the guide piece via the bolts. In the practice of underground mining, the exchange of the guide piece with the bolts guided through its base has proven to be awkward and requires a great deal of effort. Therefore the purpose of the invention is to provide a mining machine of the type mentioned above in which replacement of the guide piece is easier to achieve. SUMMARY OF THE INVENTION This object according to the invention is achieved in that the guide pawl that serves to receive the exchangeable guide piece has, or forms, at least one support on or against which the guide piece can support itself, and that a locking mechanism is provided with which the guide piece is fixed in its installation position against the guide pawl in the longitudinal direction of the guide rail, i.e. parallel to the direction of movement of the plough. With the mining machine according to the invention, the weight of the guide piece is no longer held on the guide pawl by a bolt connection that is to be established, but rather by said support or more specifically by a plurality of positive locking supports. The support or the plurality of supports, and the guide piece they support, are preferably made so that the guide piece can be pushed or moved parallel to the direction of movement of the mining machine into a corresponding mounting at the guide pawl, wherein the guide piece then comes into positive locking contact with the projections on the guide pawl that form the support. The guide piece, the weight of which is now held by the positive or form-locking connection, is only fixed by the locking mechanism transverse to the positive direction of the weight, especially in the longitudinal direction of the guide piece or in the longitudinal direction of the guide rail. For downward support, the guide piece can additionally have at least one lug to create or effect a further support, which lug engages in a correspondingly formed recess on the guide pawl, especially an open-rim recess. It is also possible for the guide pawl to have a lug or a projection that co acts with a corresponding recess on the guide piece. Lugs, projections and/or corresponding recesses, for example groove-shaped recesses, can also extend over the entire length of the guide piece, wherein the guide piece advantageously can be pushed into the holding fixture of the guide pawl like a drawer and can be supported therein. In the preferred embodiment, a support is provided on the guide pawl at both respective sides of the guide piece. In a preferred embodiment, a bolt can be provided as a locking mechanism that engages through at least one bore in the side walls of the guide pawl and against which the guide piece abuts in the lateral direction or in the longitudinal direction of the guide rail. A securing device can be provided to ensure that the bolt does not release itself from its locking position. For example, the bolt can be provided with a thread at one end to receive a nut. In its position of use, the guide piece, according to the invention, for a mining machine with the aforementioned features engages around the guide rail from above and is configured in a U-shape with two limbs that are at a distance from one another. It characterises in that projections and/or recesses are provided on the outer sides of the limbs, with which the guide piece can support itself with positive (form-) locking on the guide pawl in the vertical direction. In a preferred embodiment, an edge is formed on the first front end that projects with regard to the outer sides of the limbs and with regard to an outer side of a transverse web that connects the limbs. From this projection, a rear side of the edge results that serves as an abutment of the guide piece on a front surface of the guide pawl. It is also preferred that a projection or lug is formed on the respective outer sides of the limbs which projection or lug extends from the edge in the longitudinal direction of the guide piece. It is also preferred that on a second front end of the guide piece a recess is provided on one limb each which recess is preferably open in the direction of the second front end. The recess is preferably disposed on the outer side of a limb but it can also involve the entire wall thickness of the limb. It is preferred that the recess is defined as a semi-circle. In order to facilitate the insertion of a round lug or the like into the recess, wherein the lug and the recess engage with positive locking, the front-side opening of the recess can be opened out further by means of a chamfer or an inclination. The inclination can be disposed at an upper end of the recess so that it slightly lifts the guide piece when it abuts the lug on insertion into the holding fixture of the guide pawl. It is also preferred that at least one groove, extending from limb to limb, is formed on the outer side of the transverse web that connects the two opposed limbs. Preferably, the groove can be semi-circular in cross-section and, at least in part, can receive a bolt or the like in its longitudinal direction. If the guide piece is fixed in its position of use both in the upward direction by the abutment of the guide pawl that engages around the guide piece from above and that is open to the bottom, and in the downward direction by the holding fixture of the guide pawl, the guide piece can be locked in the lateral direction, that is, in the direction of movement of the extraction machine, by the bolt that engages in the groove and is rigidly connected to the guide pawl. The guide piece preferably forms a wearing part that is easy to replace. To this end, an area with increased resistance to wear or a wearing plate can especially be provided on an inner side of at least one limb. The increased resistance to wear can especially be attained by inductive hardening. It is also possible to provide recesses on the inner sides to receive wear inlays, preferably made of hard metal. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be explained in greater detail with reference to an example shown in the drawings. It shows: FIG. 1 a schematic view of a section of a plough guide with a plough including a guide piece guided along the plough guide; FIG. 2 a front elevation of the guide pawl of the plough according to FIG. 1 without the guide piece; FIG. 3 a sectional view along line III—III in FIG. 1 ; FIG. 4 a sectional view along the line IV—IV in FIG. 3 ; FIG. 5 an individual view of the guide piece of the plough according to FIG. 1 in an increased scale; FIG. 6 a side elevation of the guide piece; FIG. 7 a top view of the guide piece; and FIG. 8 a perspective view of the guide piece. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 indicates a face conveyor 1 laid out before a coal head (not illustrated), of which conveyor only a face cutting-side profile 2 and a conveyor base 3 are shown. A plough guide 4 is attached to the side profile 2 of the face conveyor 1 on the face-cutting side, here shown schematically only in outline. The plough guide 4 , like a track of conveyor pans of the face conveyor, comprises individual sections that can be angled slightly with respect to each other in the horizontal and vertical plane. The plough guide 4 comprises a rail 6 angled at an acute angle to the floor 5 , on which a plough 7 is supported on its two front-side ends by means of a sliding runner 8 each, of which only one sliding runner 8 is shown in FIG. 1 . Above the rail 6 , the plough guide has a lower chain channel 9 and an upper chain channel 10 , through which the runs of an endless plough chain 11 extend to drive the plough 7 along the plough guide 4 . A bearing journal 12 is formed on the plough body of the plough 7 for a pivotable mounting of a cutting bar, not illustrated, on which tools are disposed to dislodge, for example, coal. The plough guide 4 has an upwardly-directed guide rail 13 at its apex. An upper guide pawl 14 engages over the guide rail 13 at both face-side ends of the plough 7 like a hook. Between the guide pawl 14 and the guide rail 13 a U-shaped guide piece 15 is provided that can be detached from the guide pawl and replaced because it is exposed to increased wear and is therefore a wearing item. Here, the guide piece 15 sits in a similarly U-shaped holding fixture of the guide pawl 14 that is open to the bottom. Crane eyelets 16 are disposed on an upper side of the plough 7 , with which the plough 7 can be lifted with suitable lifting means. FIG. 2 shows a front view of one the guide pawls 14 of the plough with the guide piece removed. The holding fixture 40 of the guide pawl that is open to the bottom and to the rear is limited by two lateral side walls 41 , 42 and an upper wall 43 that connects these. The three walls 41 , 42 , 43 being arranged in a U-form are provided with a continuous step 44 on their inner sides so that the walls 41 , 42 , 43 form a U-shaped rear stop face 45 for the guide piece within the holding fixture, whilst the face sides 41 ′, 42 ′ and 43 ′ of the walls 41 , 42 , 43 form a front stop for the guide piece. FIG. 3 and FIG. 4 show, by means of a horizontal longitudinal section, the installation position of the guide piece 15 in the guide pawl 14 . It can easily be seen that the rear stop face 45 is disposed at the rear end of the holding fixture 40 . It can also be seen from FIG. 2 and FIG. 3 that on the one hand, a rectangular recess 46 , 47 is formed in the face side 41 ′, 42 ′ of both side walls 41 , 42 which recesses are open to the inner sides and that on the other hand, two lug stumps 48 , 49 project over the inner sides of the side walls 41 , 42 directly before the stop wall 47 which lug stumps particularly can be formed by the ends of two bolt lugs 53 , 54 immovably mounted in transverse bores 51 , 52 in the side walls 41 , 42 . The projecting ends of the bolt lugs 53 , 54 , configured as lug stumps 48 , 49 , form a first support, designated in its entirety with 55 , on which the guide piece 15 is supported in a positive form-locking manner against the guide pawl 14 in its installation position, and the recesses 46 , 47 in the front sides 41 ′, 42 ′ form a second support, designated in its entirety with 56 , for the guide piece 15 against the guide pawl 14 , as will be explained below. Firstly, the structure of the guide piece 15 , shown in detail in FIGS. 5 to 8 , will now be explained. Here, FIG. 5 shows an enlarged detail view of the guide piece 15 that is recognisable in front elevation in FIG. 1 . FIG. 6 shows the guide piece from the side, whilst FIG. 7 shows a top view of one half of the guide piece 15 . Two limbs 17 , 18 of the guide piece 15 , set apart from one another, are connected by a perpendicularly-set base or transverse web 19 . The guide piece 15 has an edge 21 on a first front end 20 that projects with regard to the outwardly-directed sides (outer sides 22 , 23 ) of the limbs 17 , 18 and over the outer side 24 of the transverse web 19 . A rear side 25 of the edge 21 results from this projection that faces away from the first front side of the guide piece 15 and in the installation position of the guide piece 15 abuts on the front side ( 43 ′, FIG. 2 ) of the upper wall ( 43 , FIG. 2 ) of the guide pawl ( 14 , FIG. 2 ). The corners of the edge 21 are rounded and their edges are chamfered. On a second front end 26 the guide piece 15 has semi-circular recesses 27 , 28 that are open to the front side 26 on its limbs 17 , 18 , into which, in the installation position of the guide piece 15 , as especially shown in FIG. 2 to FIG. 4 , the lug-shaped stumps 48 and 49 , that are round in cross-section and that project into the holding fixture 40 within the guide pawl 14 , engage in a positive form-locking manner to provide the first support 55 for the guide piece 15 . The guide piece 15 is therefore supported in a positive locking manner by these stumps in the downward direction on the second front end 26 . Both recesses 27 , 28 have a rounded portion 29 on their upper, front-side end that facilitates engagement of the lug stumps ( 49 , FIG. 4 ) in the recesses 27 , 28 when the guide piece 15 is inserted into the holding fixture ( 40 , FIG. 4 ) of the guide pawl. Furthermore, in each case a lug-like projection 30 , 31 is formed onto the two outer sides 22 , 23 of the guide piece 15 , extending in the direction of the second front end 26 . The projection 30 , 31 has a cross-section that is basically rectangular. Both, the longitudinal edges 32 that extend in the longitudinal direction and the front edges 33 that extend perpendicular thereto of the projection 30 , 31 , are chamfered. The chamfered edges 32 , 33 of the projections 30 , 31 and the rounded portions 29 of the recesses 27 , 28 facilitate their engagement in the associated, open-rim recesses ( 46 , 47 , FIG. 2 ), that are formed within the holding fixture of the guide pawl in a corresponding position, as explained above. In this way, the guide piece 15 is also supported, positive locking, on the second front end 20 by the guide pawl in the downward direction, therefore in the vertical direction, on both sides by a further support ( 56 , FIG. 4 ), wherein the guide piece 15 is held in position without detachable attachment means. It can easily be seen from FIG. 4 that in each case a lug stump 49 on the guide pawl 14 forms a first support 55 with the associated recess 27 in the guide piece 15 and in each case a projection 30 on the guide piece 15 forms a further support 56 with the associated recess 47 in the guide pawl 14 , wherein the guide piece 15 supports itself on both sides of the guide pawl 14 on this total of four supports 55 , 56 . As can especially be seen in FIG. 6 and FIG. 7 , two semicircular grooves 34 , 35 extend between the limbs 17 , 18 on the outside 24 of the transverse web 19 . The grooves extend perpendicular to the longitudinal direction of the guide piece 15 and therefore also, in the installation position of the guide piece, perpendicular to the guide rail ( 13 , FIG. 1 ). The groove 34 is set adjacent to the first front end, whilst the groove 35 is formed adjacent to the second front end. As can especially be seen from FIG. 4 , the grooves 34 and 35 together with correspondingly-configured grooves 60 open in the downward direction, in the side walls of the guide pawl 14 , each form a channel with a round cross-section that serves for insertion of a locking bolt 61 or 62 . Since the bolts 61 , 62 on both sides of the guide piece penetrate closed-rim bores 64 in the side walls 42 of the guide pawl 14 , at least at their ends, the position of the guide piece 15 in the holding fixture 40 of the guide pawl 14 is fixed by the bolts 61 , 62 as a locking mechanism. FIG. 8 shows the guide piece in a perspective view. Even the longitudinal edges 36 , on which the outer sides 22 , 23 of the limbs 17 , 18 abut on the outer side 24 of the transverse web 19 are chamfered, wherein the guide piece 15 has no projecting edges that could be easily damaged. The inner sides 37 , 38 of the limbs 17 , 18 are inductively hardened to obtain a hardened, wear-resistant surface at those points where the guide piece comes into contact with the guide rail 13 . Preferably, the hardened surface exceeds a hardness of 52 HRC.	A mining machine for underground mining is disclosed, particularly an extraction or coal plough. When in use, the mining machine is guided along a machine guide, said machine guide including a guide rail and a guide pawl. The guide pawl engaging around said guide rail from above wherein a guide piece is disposed between said guide pawl and said guide rail. The guide piece is releasably attached or attachable to said guide pawl and is sliding along said guide rail. According to the invention, said guide pawl has at least one support means whereassaid guide piece in its installation position is supported on said support means. Further, the guide piece with said guide pawl is fixed by means of a locking mechanism in the longitudinal direction of said guide rail.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to burial crypts and a method of installing the same in a burial area where the general area is first excavated, the crypts installed and the area back filled to re-establish a desirable surface contour. 2. Description of the Prior Art Prior burial crypts have generally comprised concrete vault-like structures and it has been proposed that such structures be pre-positioned in a burial area and back filled for subsequent opening and use. See for example U.S. Pat. No. 3,295,271 and U.S. Pat. No. 3,772,826. Many variations in concrete vaults and crypt-like structures have been proposed and representative structures may be seen in patents Nos. 1,030,385, 1,333,423, 1,959,204 and 3,230,674. The present invention discloses the use of a relatively lightweight burial vault or crypt formed of a synthetic resin with relatively thin walls and a method of installing the burial crypts in closely spaced relation with the side walls of the same being interconnected for mutual support and facilitating the leveling and positioning of the individual burial crypts in a pre-excavated burial area. SUMMARY OF THE INVENTION A burial crypt and a method of installing a plurality of the same utilizes a lightweight, relatively thin walled crypt and cover formed of a suitable synthetic resin with means interconnecting the side walls of adjacent crypts to provide a reinforcing effect and a desirable relative positioning of the crypts in side by side arrangement. A plurality of the crypts are installed in a pre-excavated burial area in which an under drainage system has been installed and leveling devices are positioned on the drainage material such as gravel to facilitate the leveling of the individual crypts in their multiple side by side arrangement in the burial area. DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective elevation with parts in cross section and parts broken away showing a pair of the burial crypts in a common excavation, FIG. 2 is an enlarged end elevation of the burial crypts seen in FIG. 1 of the drawings, FIG. 3 is a bottom view of one of the burial crypts seen in FIGS. 1 and 2 of the drawings, FIG. 4 is a horizontal section on line 4--4 of FIG. 3, FIG. 5 is a plan view of a portion of a perforated guide member as seen in FIGS. 1 and 2 of the drawings, FIG. 6 is a side elevation of a wedge member as seen in FIG. 2 of the drawings, and FIG. 7 is an enlarged detailed view of an interconnecting reinforcing and adjustment member as seen in FIG. 2 of the drawings. DESCRIPTION OF THE PREFERRED EMBODIMENT The burial crypt and the method of installing a plurality of the same in a pre-excavated burial area which is subsequently back filled to form the desirable contour of a cemetary is disclosed in FIG. 1 of the drawings and by referring thereto it will be seen that the earth 10 has been excavated to a level L, perforated drain tiles 10 installed and led to a suitable drain point and a covering filling of drainage material such as gravel 11 installed thereover. A pair of track-like guides 12, each of which have a plurality of longitudinally spaced perforations 13 are positioned in spaced parallel relation on the gravel or other drainage material 11. A plurality of individual crypts generally indicated at 14 are then installed on the track-like guides 12 in side by side rather closely spaced relation. Each of the burial crypts 14 has an integrally formed bottom 15, side walls 16 and a removable cover 17. The bottoms 15 are apertured as at 18 so that any liquid entering the crypts 14 will drain outwardly through the gravel or drainage material 11 and be disposed of through the perforted drain tile 10. By referring to FIGS. 1 and 2 of the drawings, it will be seen that each of the individual crypts 14 are provided with brackets 19 on their opposite upper sides, the brackets 19 preferably being slotted as at 20 so that a plurality of connectors 21 may be engaged therein to adjustably join the side walls of the burial crypts 14 to one another as best seen in FIG. 2 of the drawings. Each of the connectors 21 is formed of a pair of oppositely disposed flanged end members 22 which are internally threaded so as to engage the opposite ends of a threaded bar 23. The middle portion of the threaded bar 23 is provided with an enlarged section having multiple flat areas 24 to facilitate receiving a wrench or the like by which the threaded bar 23 may be revolved to move the flanged end members 22 in an expanding or contracting action. In FIG. 2 of the drawings, it will be seen that the connectors 21 are thus capable of moving the adjacent burial crypts 14 into satisfactory position and alignment with one another and at the same time tension the same so as to provide mutual reinforcing support of the joined side walls of the burial crypts. Still referring to FIG. 2 of the drawings, it will be seen that when the level L of the excavation is angularly disposed, wedges 25 having depending bosses 26 as best seen in FIG. 6 of the drawings are positioned on the track-like guides 12 and used to level the burial crypts 14 as desired. By referring to FIG. 1 of the drawings again it will be seen that once the individual burial crypts 14 are positioned on the track-like guides 12, and leveled where necessary through the use of the wedges 25, the covers 17 having been installed earlier or at this time if desired and gravel or other suitable drainage material is then back filled around the burial crypts 14 between them and in overlying relation with respect to the covers 17 for several inches. The earth which was previously excavated from the burial area is then refilled as indicated by the numerals 10A in FIG. 1 of the drawings and eventually grass is established thereon either by seeding or sodding and in the area indicated by the numeral 10B. Thus a burial area is formed which may be quite extensive and include a great many of the individual burial crypts 14 which are then sold along with the burial plots in the cemetary incorporating the burial area. At the time of use it is relatively simple and easy to excavate the earth 10A above the pre-positioned burial crypts 14 and the same are then readily available for receiving a casket as will be understood by those skilled in the art. By referring now to FIG. 3 of the drawings a bottom view of one of the burial crypts 14 may be seen and it will be observed that it has transversely positioned channels 27 formed in the bottom with depending pins 28 positioned therein. These channels 27 receive the track-like guides 12 as seen in FIGS. 1 and 2 of the drawings and heretofore descirbed and as illustrated in enlarged detail in FIG. 5 of the drawings and the pins 28 register with the perforations 13 in the track-like guides 12 so that the individual burial crypts 14 are positioned in fixed relation relative thereto and will retain that positioning when the gravel or drainage material 11 is installed as heretofore described. It will thus be seen that a burial crypt of relatively thin wall, lightweight construction has been disclosed together with a method of installing the same in interlocking, inter-dependent supporting relation to adjacent similar burial crypts, each of which is provided with a cover and the cover in turn is provided with ribs, the ends of which are tapered so as to insure the desirable spacing of the side walls 16 of the crypts with respect to one another. The arrangement and the method disclosed is such that the crypts retain their desired level uniformly spaced relation during the back filling of the drainage material or gravel and the earth thereover and thus insure the accurate and desirable positioning necessary in the completed burial area of the cemetary all of which contributes to the efficient and relatively inexpensive opening of the crypt at the time of need.	A plurality of burial crypts of identical configuration are arranged in a pre-excavated burial area in side by side relation, leveled with respect to one another by interconnecting adjustable means and the areas therebetween and thereover back filled whereby access can be obtained to any given crypt with a minimum of effort and whereby the crypt can be sold as a part of the cemetery plot with an improved utilization of the burial area.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND [0001] This invention relates generally to drilling of wells and production from wells. [0002] Generally, wells are drilled in a slightly over-balanced condition where the weight of the drilling fluid used is only slightly over the pore pressure of the rocks being drilled. [0003] Drilling mud is pumped down the drill string to a drill bit and used to lubricate and cool the drill bit and remove drilled cuttings from the hole while it is being drilled. The viscous drilling mud carries the drilled cuttings upwardly on the outside and around the drill string. [0004] In a balanced situation, the density of the mud going downwardly to the drill bit and the mud passing upwardly from the drill bit is substantially the same. This has the benefit of reducing the likelihood of a so-called kick. In a kick situation, the downward pressure of the drilling mud column is not sufficient to balance the pore pressure in the rocks being drilled, for example of gas or other fluid, which is encountered in a formation. As a result, the well may blowout (if an effective blow out preventer (BOP) is not fitted to the well) which is an extremely dangerous condition. [0005] In underbalanced drilling, the aim is to deliberately create the situation described above. Namely, the density or equivalent circulating density of the upwardly returning mud is below the pore pressure of the rock being drilled, causing gas, oil, or water in the rock to enter the well-bore from the rock being drilled. This may also result in increased drilling rates but also the well to flow if the rock permeability and porosity allowed sufficient fluids to enter the well-bore. [0006] In this drilling environment it is general practice to provide a variety of blowout preventers to control any loss of control incidents or blowouts that may occur. [0007] A variety of techniques have been utilized for underbalanced or dual gradient drilling. Generally, they involve providing a density lowering component to the returning drilling mud. Gases, seawater, and glass beads have been injected into the returning mud flow to reduce its density. [0008] In deep subsea applications, a number of problems may arise. Because of the pressures involved, everything becomes significantly more complicated. The pressure that bears down on the formation includes the weight of the drilling mud, whereas the pressure in the shallow formations is dictated by the weight of seawater above the formation. Because of the higher pressures involved, the drilling mud may actually be injected into the formation, fracture it and may even clog or otherwise foul the formation itself, severely impairing potential hydrocarbon production. BRIEF DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 is a schematic depiction of one embodiment of the present invention; [0010] FIG. 2 is an enlarged schematic depiction of the subsea shut-off assembly shown in FIG. 1 in accordance with one embodiment of the present invention; [0011] FIG. 3 is an enlarged, schematic, cross-sectional view of the spool 34 shown in FIG. 2 in accordance with one embodiment of the present invention; and [0012] FIG. 4 is a schematic cross-sectional view of the rotating head shown in FIG. 1 in accordance with one embodiment of the present invention. DETAILED DESCRIPTION [0013] In some embodiments of the present invention, both drilling and production of fluids from a formation may occur in an underbalanced condition. As used herein, “underbalanced” means that the weight of the drilling mud is less than the pore pressure of the formation. As used herein, “dual gradient” refers to the fact that the density of fluid, at some point along its course, moving away from a drill bit, is lower than the density of the fluid moving towards the drill bit. Dual gradient techniques may be used to implement underbalanced drilling. The creation of a dual-gradient or underbalanced condition may be implemented using any known techniques, including the injection of gases, seawater, and glass beads, to mention a few examples. [0014] Referring to FIG. 1 , a drilling and production apparatus 11 may include a rotating head 10 which rotates a string for purposes of drilling a well in a subsea formation SF. The rotating head 10 rotates the string through a surface blowout preventer (BOP) stack 12 . The surface blowout preventer stack 12 may include annular blowout preventers that control the flow of fluid moving upwardly from the wellhead to the overlying floating rig 14 . [0015] The rig 14 may be tensioned using ring tensioners 16 , coupled by a pulleys 54 to hydraulic cylinders 56 to create a tensioning system 50 . The tensioning system 50 allows the upper portion of the apparatus 11 to move relative to the lower portion, for example in response to sea conditions. The system 50 allows this relative movement and adjustment of relative positioning while maintaining tension on the casing 22 , which extends from the floating rig 14 downwardly to a subsea shutoff assembly 24 . [0016] The surface portion of the apparatus 11 is coupled by a connector 20 to the casing 22 . The casing 22 is connected to the lower section of the apparatus 11 via a disconnectable latch 72 located below the sea level WL. The latch 72 may be hydraulically operated from the surface to disconnect the upper portion of the apparatus 11 from the lower portion including the subsea shutoff assembly 24 . [0017] Also provided on the rig 14 is a source of fluid that is of a lower density than the density of mud pumped downwardly through the casing 22 from the surface in one embodiment of the present invention. The lower density fluid may be provided through the tubing 60 . [0018] A hanger system 58 includes a tensioner 58 that rests on a support 56 . The hanger system 58 tensions the tensioned tubing 26 that extends all the way down to a disconnectable subsea latch 74 above the subsea shutoff assembly 24 . Like the latch 72 , the latch 74 may be remotely or surface operated to sever the tubing 26 from the subsea shutoff assembly 24 . In one embodiment, the support 56 may include hydraulic ram devices that move like shear ram blowout preventers to grip the tubing 26 . [0019] The rate of lower density fluid flow through the tubing 26 from the surface may be controlled from the surface by remotely controllable valving in the subsea shutoff assembly 24 , in one embodiment. It is advantageous to provide this lower density fluid from the surface as opposed to attempting to provide it from a subsea location, such as within the subsea shutoff assembly 24 , because it is much easier to control and operate large pumps from the rig 14 . [0020] The subsea shutoff assembly 24 operates with the surface blowout preventer stack 12 to prevent blowouts. While the surface blowout preventer stack 12 controls fluid flow, the subsea shutoff assembly 24 is responsible for cutting off or severing the wellhead from the portions of the apparatus 11 thereabove, using shear rams 30 a and 30 b as shown in FIG. 2 . Thus, the casing 22 may be coupled by connector 28 a to the shear ram 30 a . The shear ram 30 a is coupled by a spool 34 with flanges 32 a and 32 b to the shear ram 30 b . The shear ram 30 b may be coupled through the flange 38 to a wellhead connector 28 b , in turn connected to the wellhead. [0021] As shown in FIG. 2 , the tubing 26 connects to a remotely controlled valve 36 that controls the rate of lower density fluid flow through the tubing 26 to the interior of the spool 34 . The inlet from the tubing 26 to the spool 34 is between the two shear rams 30 a and 30 b. [0022] The injection of lower density fluid, as shown in FIG. 3 , makes use of the remotely controlled valve 36 on a spool 34 . The spool 34 may have drilling mud, indicated as M IN , moving downwardly through the casing 22 . The returning mud, indicated as M OUT , extends upwardly in the annulus 46 surrounding the string 40 and annulus 44 . Thus, lower density fluid may be injected, when the valve 36 is opened, into the returning mud/hydrocarbon flow to lower its density. [0023] An underbalanced situation may be created as a result of the dual densities of mud in one embodiment. Namely, mud above the valve 36 may be at a lower density than the density of the mud below the valve 36 , as well as the density of the mud moving downwardly to the formation. The valve 36 may include a rotating element 37 that allows the valve 36 to be opened or controlled. As an additional example, the valve 36 may be a pivoted gate valve with a hydraulic fail safe that automatically closes the valve in the event of a loss of hydraulics. The valve 36 may enable the extent of underbalanced drilling to be surface or remotely controlled depending on sensed conditions, including the upward pressure supplied by the formation. For example, the valve 36 may be controlled acoustically from the surface. [0024] Thus, in some embodiments of the present invention, flow control may be done most effectively at the surface, whereas shutoff control is done on the seafloor bed. The pumping of the lower density fluid is also done on the surface, but its injection may be done at the subsea shutoff assembly 24 , in one embodiment between the shear rams 30 a and 30 b. [0025] The rotating head 10 , shown in more detail in FIG. 4 , is coupled to the surface blowout preventer stack 12 at a joint 70 . Returning fluid, indicated as M OUT , is passed through a valve 68 to an appropriate collection area. The collection area may collect both mud with entrained debris, as well as production fluids such as hydrocarbons. The production fluids may be separated using well known techniques. [0026] The upward flow of the fluid M OUT is constrained by a packer 62 . In one embodiment, the packer 62 is a rubber or resilient ring that seals the annulus around the string 40 and prevents the further upward flow of the fluids. At the same time, the packer 62 enables the application of a rotating force in the direction of the circular arrow from the rotating head 66 to the string 40 for purposes of drilling. Seals 65 may be provided between a telescoping joint 64 and the rotating head 66 as both drilling and production may be accomplished in an underbalanced situation. [0027] Thus, in some embodiments of the present invention, a subsea shutoff assembly 24 may be provided to cut off the string in the event of a failure, such as a blowout. At the same time, surface annular blowout preventers control fluid flow. Dual gradient drilling may be achieved through the provision of fluid from the surface through a side inlet into the region between the upper and lower ram type shear blowout preventers 30 . Through the provision of the separate tubing 26 with a remotely operable latch 74 , appropriate volumes of fluid can be achieved that would not be available with conventional kill and choke lines. The tubing 26 for providing the density control fluid may be both tensioned and latched. As a result, dual gradient production and drilling may be achieved in some embodiments of the present invention. [0028] While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.	Underbalanced production and drilling may be achieved by a system which uses a rotating head coupled to surface blowout preventer stack for fluid flow control. A casing connects these surface components to a subsea shutoff assembly with a pair of ram shear devices to cut off the string to the wellhead. Both the casing and an alternate line may be latched so that they may be released if necessary. The alternate line may provide fluid from the surface to the subsea shutoff assembly for purposes of varying the density of the returning mud. The rotating head may include a rubber packer to prevent upward flow of drilling fluid and production hydrocarbons and, at the same time, provide rotation to the drill string.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND TO THE INVENTION The present invention relates to a mineral winning machine and particularly, but not solely, to coal ploughs. It is known to construct a coal plough with adjustable tool carriers or holders and various designs have been employed in the art. The adjustment of the carriers may involve a pivoting action effected by the engagement of the coal face or effected by adjusting devices mounted on the plough structure itself. It is also known to supply water to spray nozzles on a coal plough to suppress dust. For this purpose a trailing hose accommodated in a trough carrier by a longwall conveyor can be used to supply the water. It has been proposed to utilize this water supply to effect adjustment or other operations of the plough -- see for example, German patent specification No. 2254774. However, the use of low pressure of the water supply for the nozzles necessitates unduly large control components. To overcome this problem it has also been proposed to provide the plough with a high-pressure pump and drive motor but the resulting construction is subject to corrosion problems and any fluctuation in the low pressure water supply can adversely affect the operation of the plough. A general object of the present invention is to provide an improved form of plough. SUMMARY OF THE INVENTION In accordance with the invention a mineral winning machine or coal plough of the type adapted to be moved back and forth along a mineral or coal face has a body with adjustable cutting tool carriers, means supported by the body for effecting adjustment of said carriers and a composite flexible line for providing both motive power for the adjusting means and remotely-initiated control signals for controlling the selective operation of the adjusting means. The adjusting means may comprise hydraulically operated devices, such as piston and cylinder units, supplied with a high pressure motive fluid via a pressure conduit or duct of the flexible line. Control valves responsive to the control signals, which may be of hydraulic, pneumatic or electric nature, can be provided on the body to connect desired devices or units to the motive pressure fluid. To reduce the number of control valves required it is useful to have a single common valve controlling several devices or units from one control line. Furthermore, valves responsive to different control pressures can be used. Double-acting piston and cylinder units are a preferred form of device for adjusting the tool carriers although units with spring biased pistons can be used. The flexible line preferably has a plurality of control lines or conduits for the control signals mounted in an assembly with the high pressure conduit and enclosed in a protective outer sheath. In known manner, the flexible line can be trailed by the machine and looped in a protective trough. In one constructional embodiment of the invention, described hereinafter, a low pressure oil or oil/water emulsion is used to provide the control signals while a high pressure oil or oil/water emulsion provides the motive power. The machine or plough can be propelled by an endless chain or by drive means supported by its body. In this latter case the drive means can also be supplied with motive power from flexible line. Water-spraying nozzles supplied with water via the flexible line can also be mounted to the body. In a coal plough made in accordance with the invention all the setting operations can be initiated by remote generation of control signals. Thus, for example, the floor cutters can be set to control the cutting path of the plough, various tool carriers can be pivoted to bring their cutters into operative or non-operative positions and roof cutters can be raised or lowered. The invention may be understood more readily and various other features of the invention may become apparent from consideration of the following description. BRIEF DESCRIPTION OF DRAWINGS An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: FIG. 1 is a diagrammatic end view of a mine installation employing a mineral winning machine made in accordance with the invention; FIG. 2 is a diagrammatic elevation of the machine as seen from the mineral face; and FIG. 3 is a cross-sectional view of the composite hose line for the machine. DESCRIPTION OF PREFERRED EMBODIMENT As shown in FIGS. 1 and 2, a mineral winning machine in the form of a coal plough 10 is guided in known manner by guide means 11 located at the coal-face side of a longwall scraper-chain conveyor 12. In known manner, the plough 10 is moved back and forth along the guide means 11 to strip coal from the coal face 13. An endless chain running in guide channels located inside shaped ramp plates of the guide means 11 serves to slidably move the plough along the guide means 11. The plough 10 itself has guides 14 extending into the lower guide channel and drivably coupled with the drive chain and these guides 14 connect with skids 15 slidably supported by extended foot plates of the guide means 11. The plough 10 has a main body 16 of arch or portal configuration with end portions engaging on the skids 15. The body 16 is provided with various sets of cutting tools or cutters supported by mounting pieces or carriers. As shown in FIG. 2, the end portions of the plough body 16 are equipped with floor cutters supported by carriers 17, 17'. The carriers 17, 17' are adjustable in the directions of arrows A to control the cutting position of the plough. The adjustment of the carriers 17, 17' is effected by double-acting hydraulic piston and cylinder units 18, 18'. The units 18, 18' have their cylinders supported by the end portions of the plough body 16 and their piston rods coupled to the carriers 17, 17' via cranked elbow levers 19, 19'. Above the carriers 17, 17' there are carriers 20, 20' provided with vertically staggered cutters in echelon configuration. The carriers 20, 20' are adjustable about inclined axes 21, 21'. The adjustment of the carriers 20, 20' is effected by double-acting hydraulic piston and cylinder units 22, 22'. The units 22, 22' have their cylinders supported by the end portions of the plough body 16 and their piston rods coupled to the upper parts of the carriers 20, 20'. Further carriers 23, 23' are located at the ends of the plough above the carriers 20, 20'. These carriers 23, 23' support sets of vertically arranged cutters and the carriers 23, 23' are adjustable about vertical axes 24, 24'. The adjustment of the carriers 23, 23' is effected by double-acting hydraulic piston and cylinder units 25, 25'. The units 25, 25' have their cylinders supported by the end portions of the plough body 16 and their piston rods coupled to the lower parts of the carriers 23, 23'. At the central arch portion of the plough body 16 there are carriers 26, 26' provided with vertically arranged cutters. The carriers 26, 26' are adjustable in the directions of arrows B. This adjustment is effected by double-acting hydraulic piston and cylinder units 27, 27' arranged in vertical orientation. The cutters pertaining to the carriers 26, 26' are supported by holders 28, 28' pivotable about axes 29, 29' in relation to the carriers 26, 26'. The holders 28, 28' are adjustable about the axes 29, 29' with double-acting hydraulic piston and cylinder units 30, 30' coupled between the carriers 26, 26' and their respective holders 28, 28'. As shown in FIG. 1, the plough body 16 is connected to an arm or jib 31 extending over the conveyor 12 and slidably engaging on a guide rail 32 supported in an elevated position by structures 33, 34 attached to the conveyor goaf side wall. The jib 31 is telescopic and can be extended or retracted in length (arrows C) with the aid of a double-acting hydraulic piston and cylinder unit (not shown) conveniently mounted therein. The adjustment of the length of the jib 31 regulates the angular position of the plough body 16. A trough or channel 35 mounted to the structure 33 accommodates a flexible looped supply line 36. In known manner the line 36 is lifted from the trough 35 in a progressive manner as the plough 10 proceeds along the guide means 11 in one direction and is then laid back in the trough 35 in a loop as the plough 10 proceeds back in the reverse direction. The line 36 is guided by the jib 31 to the plough body 16 for operative connection with the units 18, 18', 22, 22', 25, 25', 27, 27' and 30, 30' and the unit for operating the jib 31, and with associated control valves (not shown). The line 36 is connected to pressure fluid supply means preferably located centrally of the longwall working. As shown in FIG. 3, the line 36 is of composite form with a flexible central duct or conduit 37 around which is arranged a plurality of further conduits 38. The conduits 38, 37 are all covered with a flexible outer sheath 39 which may be formed from strip material wound around the assembly, 38, 37 in helical manner. The central conduit 37 is fed with high pressure fluid, preferably an oil/water emulsion whereas the conduits 38 are fed with a lower pressure fluid again preferably an oil/water emulsion. The fluid supply means is preferably constructionally united with control means which selectively feeds low pressure fluid to one or more of the conduits 38. These conduits 38 connect with control valves 40 which open or close connection between the respective working chambers of the various piston and cylinder units mentioned above and the high pressure fluid, as schematically shown in FIG. 2. In this way the adjustment to the plough can be initated and controlled remotely. A return line or path for the pressure fluid can be provided and a return line leading to a reservoir can be incorporated in the composite line 36 or separate therefrom. A single common control valve can serve to control a pair of corresponding hydraulic units. Thus, for example, the units 18, 18' can have their working chamber connected to a control valve which has its supply switching state changed by a low pressure signal acting on a control or servo piston. In one state the valve connects the working chambers to the high pressure fluid supply to extend one unit 18 and retract the other 18' while conversely in the other state the unit 18 is retracted and the unit 18' extended. The arrangement can be such that the carriers and cutters at the front of the plough 10 relative to its direction of movement are all brought into an operative position whereas the corresponding carriers and cutters at the rear are all retracted and held in a withdrawn inoperative position. It is also possible to extend the control system by making certain control valves operate at different pressures and by using one control conduit 38 to supply different pressure signals to thereby actuate selected valves. The plough can also be provided with a set of nozzles 41 for dust suppression. Water can be conveyed to these nozzles by way of an additional conduit 42 in the line 36, as schematically shown in FIG. 2. One or more control valves activated by a further control conduit or conduits 38 can be used to initiate and halt the spraying action. The arrangement can also be modified so that water under pressure is also used to activate the control valves either directly or by means of a pump unit mounted on the plough and supplying fluid or water to the control valves. The use of pressure fluid for initiating the various adjustments and operations of the plough is not essential and the conduits 38 can convey pneumatic signals to the valves or else the conduits 38 can be replaced by electric cables providing electric signals to the valves. In a further modification the plough can be selfpropelled by its own drive means instead of by the more conventional endless chain. It is preferable here to adopt an arrangement where the plough drive means is mounted to the plough body and drives a toothed wheel which engages with a toothed rack or an apertured rail mounted on or alongside the conveyor. The drive means can be powered with fluid from the conduit 37 or by an additional power line assembled in the hose line 36 and the operation of the drive means can be controlled with signals conveyed along the line 36.	A coal plough has a main body guided for movement back and forth along a longwall coal face. The body supports various cutting tool carriers which are adjustable with the aid of hydraulic piston and cylinder units. Fluid is supplied to these units by means of a flexible composite line which also conveys control signals remotely initiated for selecting the units to be charged with fluid to effect the adjustment desired.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION [0001] The present invention relates to a method for plastering construction of an interior wall in architectural decoration. BACKGROUND OF THE INVENTION [0002] The existing plastering construction process for architectural decoration generally includes: base treatment; hanging vertically of a plumb; perpendicularity and flatness leveling; line positioning; plaster applying; screed strips constructing on wall surfaces; manual plastering; filling of reserved holes, electric cabinet slots, electric cabinet boxes, and the like; scraping and trowelling; and waste recycling. The above existing construction process has the following disadvantages: [0003] (1) The traditional process of constructing screed strips on wall surfaces is very demanding for the skills of a plastering worker. In the case of plastering construction by an unskilled worker, the speed of the plaster applying is lowered, and it is difficult to guarantee a high precision of constructing screed strips on the wall surface, resulting in unsatisfying flatness and levelness of wall surfaces and the undesired visual effect of the wall body. Moreover, the screed strip constructing process cannot match with a mechanized construction process, leading to difficulties in significantly improving the construction efficiency. [0004] (2) During wall surface trowelling after the manual plastering or mechanical mortar spraying, due to the rotary grinding of a wooded trowel, the collision and squeeze occurred within the mortar causes the moisture in the mortar to exude from the mortar. Because of the moisture loss from the mortar to brick bodies of the wall in contact with the mortar, the moisture in the mortar is absorbed prematurely, thus the mortar shrinks and hence the wall surface plumps up, causing phenomena such as cracks in the wall surface and peeling off of the mortar. Moreover, the construction schedule is prolonged since the above processes rely on numerous technical personnel and are time consuming, and the construction efficiency is lowered since the construction processes are fussy and complicated. SUMMARY OF THE INVENTION [0005] A technical problem to be solved by the present invention is to provide a method for plastering construction, which improves the efficiency of plastering construction and guarantees high construction quality, without dependency on a technique level of a construction personnel, and may further cooperate with mechanized construction. [0006] In order to solve the above problems, the present invention provides a method for plastering construction in architectural decoration, including steps of: (1) base treatment; (2) screed strip constructing; (3) plastering; and (4) wall surface grinding. [0011] the step (2) of screed strip constructing comprises: positioning alignment wires according to an intended height of applied plaster, and installing longitudinally screed templates along a wall surface treated by the step (1) of base treatment according to a distance between the alignment wire and the wall surface, wherein a transverse interval between the adjacent screed templates is 1.3 m to 1.8 m; and [0012] the step (4) of wall surface grinding comprises that: the wall surface treated by the step (3) of plastering rests for 12 hours to 24 hours till the plastered mortar on the wall surface is semi-dry and compact and at a solidified state, and the mortar is ground to be flat by saw teeth of a running rule with saw blade abutting against the mortar along two adjacent screed templates. [0013] The base treatment in step (1) includes: cleaning and drying a wall surface; applying mortar on the wall surface; attaching a stretched fiberglass mesh on the mortar at the time of pre-hardening of the mortar, and pressing the fiberglass mesh into the mortar until the fiberglass mesh is slightly visible; applying mortar on the fiberglass mesh to completely cover the fiberglass mesh; and solidifying the mortar. [0014] The step (3) of plastering includes a mechanical mortar spraying, which includes: spraying water on the wall surface after the screed scrip constructing; spraying the plastering mortar to the wall surface by a mortar spraying machine till the screed templates are basically covered but slightly visible; scraping the wall surface by a common running rule abutting against the screed templates; and manually repairing and leveling the reserved holes or reserved positions. [0015] The screed template in the step (2) includes a base configured to be connected with the wall surface, a screed board and a connecting rod for connecting the base with the screed board; the base is provided with an installation through hole for receiving one end of the connecting rod in a direction perpendicular to the base; a side of the screed board, which is close to the wall surface, is provided with a clamping slot configured to perpendicularly receive the other end of the connecting rod along a longitudinal direction, and the screed board is connected with at least two bases via at least the connecting rods. [0016] The screed templates are installed by: sticking longitudinally the bases on the wall surface by using glue, with the adjacent bases being spaced by an interval of 50 cm; inserting one end of each connecting rod into the installation through hole, shearing the connecting rod to have a length corresponding to a distance between the alignment wire and the wall surface, and pressing the clamping slot after aligning the clamping slot with the other end of the connecting rod. [0017] The base is integrally formed by a smaller round disc and a bigger round disc which is coaxial with the smaller round disc and configured to connect with the wall surface; the installation through hole is coaxial with the bigger round disc and the smaller round disc; an end of the installation through hole, which is close to the screed board, is provided with a clamping jaw protruding towards the center of the installation through hole. [0018] Four auxiliary through holes are evenly distributed in a circumferential direction on the bigger round disc; the screed board is integrally formed by a folded plate symmetrically folded about a longitudinal direction and the clamping slot; the clamping slot is disposed on an inner concave surface of a corner of the folded plate and extends along the longitudinal direction; and both lateral sides of the folded plate are respectively provided with a plurality of through holes distributed along the longitudinal direction. [0019] A plurality of closed annular dents, which are in planes perpendicular to the longitudinal direction of the connecting rod, are evenly distributed on the connecting rod along the longitudinal direction. [0020] The running rule with saw blade in step (4) includes a saw blade that is provided with the saw teeth along the longitudinal direction and a clamping part connecting with the saw blade. [0021] A cross-sectional shape of the clamping part is approximate to an isosceles triangle, the clamping part extends at its vertex as two clamping plates for clamping the saw blade, the clamping plates and the saw blade are tightened by a bolt, and the clamping part matches the saw blade in length. [0022] A length of the saw blade is 1.7 m to 2.3 m; a distance between the saw teeth and a proximal end of the clamping plate is 30 mm to 70 mm; a width of a clamped part of the saw blade is 40 mm to 60 mm; and a width of an end surface of the clamping part, which is away from the saw blade, is 2 cm. [0023] The screeding apparatus used for the screed strip constructing of the method for the plastering construction in architectural decoration is convenient to install and use, and has a lower technical requirement on the construction personnel, while guaranteeing both the perpendicularity and the flatness of the wall surface and avoiding the dependence on the technical experiences of the construction personnel. Further, the screeding apparatus may be remained inside the wall rather than being taken out from the wall after the screed strip constructing is finished, thereby avoiding repairing at an original position of the screed strip, reducing the working procedures and improving the efficiency. Also, the screeding apparatus may cooperate with a mechanized mortar spraying operation, thereby improving the plastering efficiency. After the mechanized mortar spraying is finished, the existing manual trowelling is avoided, the plastered mortar on the wall surface rests for 12 hours to 24 hours till the plastered mortar on the wall surface is semi-dry and compact and at a solidified state, so that the problem of plumping up of the wall surface can be solved by utilizing the natural solidification of the mortar, and then the mortar is ground by the running rule with saw blade. Compared with the manual troweling, the running rule with saw blade can implement grinding at a larger area and hence is suitable for large-area construction. The running rule with saw blade is simple and convenient in operation, and has a low requirement on a technical merit and a less requirement on the quantity of the construction personnel. BRIEF DESCRIPTION OF THE DRAWINGS [0024] The present invention is described in detail below with reference to the accompanying drawings and embodiments. [0025] FIG. 1 is a front view of a screed template used in a step of screed strip constructing according to the present invention. [0026] FIG. 2 is a left view of the screed template used in the step of screed strip constructing according to the present invention. [0027] FIG. 3 is a schematic top sectional view of the screed template used in the step of screed strip constructing according to the present invention. [0028] FIG. 4 is a front view of a running rule with saw blade used in a step of wall surface grinding according to the present invention. [0029] FIG. 5 is a left view of the running rule with saw blade used in the step of wall surface grinding according to the present invention. [0030] FIG. 6 is a bottom view of the running rule with saw blade used in the step of wall surface grinding according to the present invention. [0031] FIG. 7 is a flow chart of a method for plastering construction in architectural decoration according to the present invention. DETAILED DESCRIPTION OF THE INVENTION [0032] The present invention introduces newly designed tools, i.e. a screed template and a running rule with saw blade. The use of the screed template improves the efficiency of forming screed strips, and lowers requirements for the technique level of the construction personnel, and the use of the running rule with saw blade to grind the wall surface can effectively solve the plumping up of the wall surface, and lower requirements for the technique level and quantity of the construction personnel due to the easy usage of the running rule with saw blade, which has significant meanings on saving labor costs and time costs. FIG. 7 is a flow chart of a method for plastering construction in architectural decoration according to the present invention. [0033] The method for the plastering construction in architectural decoration according to the present invention includes the following processes of: base treatment, screed strip constructing, mechanical mortar spraying and wall surface grinding. [0034] In the existing base treatment, a steel mesh for preventing cracking is fixed on the wall by nails, which are covered by plastered mortar. However, both the nails and the steel mesh remained on the wall are likely to rust, which may cause damages to the wall surface. In order to avoid the rust of the nails for fixing the steel mesh, the present invention provides a way of burying a fiberglass mesh by mortar, which can better guarantee that the wall surface after plastering construction is reliable and durable and has thermal insulation and waterproof properties, such that the traditional way of fixing the steel mesh using nails is avoided. In this way, the problem of rust of the nails can be solved, and cracks of the wall surface are prevented. [0035] The base treatment process in the present invention includes: (1) cleaning and drying a wall surface; (2) applying mortar on the wall surface; (3) attaching a stretched fiberglass mesh on the mortar at the time of pre-hardening of the mortar, and pressing the fiberglass mesh into the mortar until the fiberglass mesh is slightly visible; (4) applying mortar on the fiberglass mesh to completely cover the fiberglass mesh; and (5) solidifying the mortar. [0036] The fiberglass mesh has good chemical stability and is alkali-resistant, acid-resistant, waterproof, and cement corrosion resistant; has good physical properties such as high strength, high modulus, and light weight; and has good size stability such as rigidness, flatness, good shrinkage and deformation resistance, and excellent positioning property. The fiberglass mesh also has properties of thermal insulation, electrical insulation, and crack resistance. Moreover, a mesh size of the fiberglass mesh may be 5 mm×5 mm and a length of a single fiberglass mesh is generally no more than 6 meters. To join adjacent fiberglass meshes, a width of the overlapping portion of the fiberglass meshes shall be at least 10 cm. To press the fiberglass mesh into the mortar in the step (3), a trowel is used to flatly and firmly press the fiberglass mesh into the surface layer of the mortar from the center of the fiberglass mesh to its periphery. Folds of the pressed fiberglass mesh shall be avoided. The mortar should not be kneaded continuously to avoid the plumping up of the wall surface. [0037] After the mortar is hardened, the screed strip construction begins. [0038] As illustrated in FIGS. 1-3 , a screed template used for the screed strip construction includes a base 10 configured to be fixed on a wall surface, a screed board 30 , and a connecting rod 20 for connecting the base 10 with the screed board 30 . The same screed board 30 can connect with at least two bases 10 via at least two connecting rods 20 . Preferably, the base 10 , the screed board 30 and the connecting rod 20 each are integrally made of the recycled plastics so as to save costs and be environment friendly, or made of other materials. [0039] The base 10 is provided with an installation through hole 11 , in which the connecting rod 20 can be inserted in a direction perpendicular to the base 10 . In order to install the connecting rod 20 on the base 10 more firmly, the base 10 is integrally formed by a smaller round disc 18 and a bigger round disc 17 which is coaxial with the smaller round disc 18 and configured to connect with the wall surface. The installation through hole 11 is coaxial with the bigger round disc 17 and the smaller round disc 18 , and an end of the installation through hole 11 , which is close to the screed board 30 , is provided with a clamping jaw 12 protruding from the wall of the installation through hole 11 towards the center of the installation through hole 11 . As illustrated in FIG. 3 , the clamping jaw 12 is used for fixing the connecting rod 20 perpendicularly to the base 10 . The bigger round disc has a diameter of 60 mm and a height from 1 mm to 2 mm, and the smaller round disc has a diameter of 9 mm and a height of 3 mm. When the screed strip constructing begins, the base 10 is stuck on the wall surface by connecting the bigger round disc 17 with the wall surface. Due to the different conditions of the wall surfaces, the bigger round disc 17 is provided with at least one auxiliary through hole 13 which may have a round shape or other shape, in order to stick the base 10 on the wall surface more firmly. Preferably, a plurality of auxiliary through holes 13 , for example four auxiliary through holes as illustrated in FIG. 2 , are disposed evenly along a circumferential direction in the bigger round disc 17 . [0040] The screed board 30 is used for indicating the intended height of applied plaster, and a side of the screed board 30 , which is close to the wall surface in use, is provided with a clamping slot 33 configured to perpendicularly receive the connecting rod 20 . The screed board 30 is integrally formed by a folded plate 31 symmetrically folded about a longitudinal direction of the screed board 30 and the clamping slot 33 . The folded plate 31 is bent by an angle of 90 degrees or 60 degrees or other angles. The clamping slot 33 is disposed on an inner concave surface of a corner of the folded plate 31 and extends along the longitudinal direction. In order to prevent the plumping up due to a gap between the clamping slot 33 and the folded plate 31 , both lateral sides of the folded plate 31 are respectively provided with a plurality of through holes 32 evenly distributed along the longitudinal direction. As shown in FIG. 1 and FIG. 2 , the through holes 32 are hexagon-shaped. The mortar can be filled between the clamping slot 33 and the folded plate 31 via the through holes 32 . End surfaces of the folded plate 31 at its both sides, which are close to the base 10 , and an opening end of the clamping slot 33 are in the same plane. The folded plate 31 has a thickness from 1 mm to 2 mm, and has a width from 1 cm to 2 cm. [0041] A plurality of closed annular dents (i.e. grooves) 21 , which are in planes perpendicular to the longitudinal direction of the connecting rod 20 , are evenly distributed on the connecting rod 20 along the longitudinal direction. As illustrated in FIG. 3 , one end of the connecting rod 20 is perpendicularly inserted into the installation through hole 11 of the base 10 , so that the clamping jaw 12 clamps the dent 21 on the connecting rod 20 to fix the connecting rod 20 , and the other end of the connecting rod 20 is perpendicularly inserted into the clamping slot 33 of the screed board 30 , so that the clamping slot 33 clamps the dent 21 on the connecting rod 20 to fix the connecting rod 20 . For the screed strip constructing, the connecting rod 20 can be sheared to have a desired length depending on the intended thickness of the applied plaster. [0042] A process of the screed strip constructing includes: positioning alignment wires according to an intended height of applied plaster; sticking the bases 10 on the wall surface applied with the mortar by using glue along a longitudinal direction, with the adjacent bases 10 being spaced by an interval of 50 cm; inserting one end of each connecting rod 20 into the installation through hole 11 , shearing the connecting rod 20 to have a length corresponding to a distance between the alignment wire and the wall surface, and pressing the clamping slot 33 after aligning the clamping slot 33 with the other end of the connecting rod 20 , so that the screed templates are mounted at an interval of 1.3 m to 18 m transversely. [0043] The screed strip constructing operation of the present invention has a lower technical requirement on the workers, and the screed template has a simple structure and can be easily installed, so that the whole screed strip constructing operation can be finished independently only by the screed templates without needing any other tools or mortar materials. Since the screed templates are close to one another, the height of the applied plaster is easy to adjust and unify, such that the construction efficiency is improved. Thus, the height of the applied plaster will not be negatively affected by techniques of the workers or the deformation of mortar and the screed strips caused by collisions. The base, the connecting rod and the screed board each are integrally formed by the recycled plastics, which not only protects the environment, but also saves the cost without public hazards and pollutions, resulting in public benefit effects of “green building”. The base, the connecting rod and the screed board can be buried in the applied plaster after the plastering is finished, thereby simplifying the process and reducing the construction time. In the prior art, the plastering cannot be implemented until 2 hours after the screed strips have been constructed, while in the present invention, the plastering can be implemented immediately after the screed strip constructing is finished, thereby improving the construction efficiency. [0044] After the screed strip constructing is finished, next step of plastering is implemented. Either the manual plastering or the mechanical mortar spraying can be employed in the plastering step. The mechanical mortar spraying is implemented in the embodiment of the present invention. [0045] The process of the mechanical mortar spraying includes: spraying water on the wall surface after the screed scrip constructing; spraying the plastering mortar to the wall surface by a mortar spraying machine till the screed templates are basically covered but slightly visible; scraping the wall surface by a common running rule abutting against the screed templates; and manually repairing and leveling the reserved holes or reserved positions such as an electric cabinet, an electric cabinet slot, an electric cabinet box and the like. [0046] A mortar spraying machine of a TURBOSOL POLIT type is used for the mechanical mortar spraying in the embodiment. The mortar can be directly applied on the wall surface subjected to the base treatment via the mortar spraying machine, a delivery pipe and a spray nozzle. A thickness of the sprayed mortar is just sufficient to basically cover the screed templates but keep the screed templates be slightly visible. Each time scraping the wall surface by the common running rule abutting against the screed templates, the redundant materials can be recycled. The vacant wall surface can be manually repaired by the workers or repeatedly sprayed by the spraying machine. The above steps may be repeated to guarantee the sufficient mortar spraying. The mortar protruding slightly can achieve a better effect, and vacancy in the wall surface shall be avoided as possible. [0047] The manual plastering needs for a large number of technical personnel and takes a long construction time, which influences the construction schedule. In addition, the construction process is fussy and complicated, which influences the construction efficiency. [0048] Compared with the manual plastering, the mechanical mortar spraying greatly improves the efficiency of the mortar spraying and is suitable for the large-area construction, thus a requirement on the quantity of the construction personnel is reduced and the labor cost is saved. [0049] As a difference from the prior art, a manual trowelling procedure in the plastering operation is cancelled and the step of grinding the wall surface is added in the present invention. The plasticity of the plastered mortar is strong when the plastering is finished because the plastered mortar is in a pre-hardening state. During the manual trowelling process, due to the rotary grinding of a wooded trowel, the collision and squeeze occurred within the mortar causes the moisture in the mortar to exude from the mortar. Because of the moisture loss from the mortar to brick bodies of the wall in contact with the mortar, the moisture in the mortar is absorbed prematurely, thus the mortar shrinks and hence the wall surface plumps up, causing phenomena such as cracks in the wall surface and peeling off of the mortar. Therefore, in the present invention, the plastered mortar on the wall surface rests for 12 hours to 24 hours till the plastered mortar on the wall surface is semi-dry and compact and at a solidified state, so that the problem of plumping up of the wall surface can be solved by utilizing the natural solidification of the mortar, and then the mortar is ground by the running rule with saw blade. Compared with the manual troweling, the running rule with saw blade can implement grinding at a larger area and hence is suitable for large-area construction. The running rule with saw blade is simple and convenient in operation, and has a low requirement on a technical merit and a less requirement on the quantity of the construction personnel, further, the plumping up can be better avoided. The grinding operation can be implemented by either the manual plastering or the mechanical mortar spraying. [0050] FIGS. 4-6 illustrate structural views of the running rule with saw blade used for grinding the wall surface, and the running rule with saw blade includes a saw blade 300 , a clamping part 200 for clamping the saw blade 300 , and a bolt 100 for fastening the saw blade 300 and the clamping part 200 . Teeth, which may be general teeth, are disposed along the longitudinal direction of the saw blade 300 . The length of the saw blade 300 is 1.7 m to 2.3 m, preferably, 2 m in the embodiment, so as to match with the screed templates arranged at an interval of 1.3 m to 1.8 m. The width of the saw blade 300 is 0.1 m to 0.2 m, and the thickness of the saw blade 300 is 1 mm. [0051] For ease of the construction, the clamping part 200 is connected to a side of the saw blade 300 , which is opposite to the teeth, and is disposed along the longitudinal direction. Preferably, the length of the clamping part 200 matches with the saw blade 300 . A cross-sectional shape of the clamping part 200 is approximate to an isosceles triangle, the clamping part 200 may be formed by an aluminum alloy plate, and the clamping part extends at its vertex as two clamping plates 210 for clamping the saw blade 300 . The bottom side of the clamping part 200 , that is, an end surface of the clamping part 200 which is away from the saw blade 300 , has a width of 2 cm, so that the clamping part 200 is convenient for griping by a worker. A distance between the teeth of the saw blade 300 and the end of the clamping plate 210 is 30 mm to 70 mm, and a width of a part of the saw blade 300 , which is clamped by the clamping plates 210 , is 40 mm to 60 mm. In the embodiment, the whole width of the saw blade 300 is 0.1 m, a distance between the teeth of the saw blade 300 and a proximal end of the clamping plate 210 is 50 mm, and a width of the part of the saw blade 300 which is clamped is 50 mm. [0052] To fix the saw blade 300 between the clamping plates 210 of the clamping part 200 , at least two bolts 100 (cooperate with corresponding nuts) are needed for fastening the clamping plates 210 and the saw blade 300 to clamp the saw blade 300 . As illustrated in FIG. 4 , two bolts 100 are respectively disposed at two ends of the clamping part 200 , and one of the two bolts 100 is close to the teeth and the other one is away from the teeth, thereby achieving the fixation purpose. [0053] A wall surface grinding process is as follows: after the mechanical mortar spraying is finished, the plastered mortar rests for 12 hours to 24 hours till the plastered mortar is semi-dry and compact and at a solidified state, subsequently the construction personnel can grip the clamping part 200 to grind the mortar along two neighboring screed templates from bottom to top, where the teeth abuts against the plastered mortar and the saw blade 300 inclines to the wall surface by an angle in the range from 30 degrees to 60 degrees. [0054] Upon inspection, both the flatness of the wall surface and perpendicularity at internal and external corners of the wall meet the national standards. Moreover, plumping up, cracks and watermarks do not occur to the wall surface.	A method for plastering construction in architectural decoration comprises the following steps: (1) base treatment; (2) performing construction positioning paying-off according to the required plastering height, and longitudinally installing screeding templates along a wall surface subjected to the base treatment in Step (1) according to the paying-off height, a lateral space between adjacent screeding templates being 1.3 to 1.8 meters; (3) plastering; and (4) laying aside the wall surface subjected to the plastering for 12 to 24 hours till plastering mortar on the wall surface is in a half-dried compact hardened state, and using teeth of a saw blade for grinding the mortar along the two adjacent screeding templates through a ruler till the mortar is even. The method can improve the construction efficiency and guarantee the construction quality.
You are an expert at summarizing long articles. Proceed to summarize the following text: [0001] The rain and storm water filtration systems discussed herein relate to filtration systems that employ screens to filter debris and other unwanted material from water streams and, more specifically, to filtration systems having a screen comprising a plurality of wedge wires or tilted wedge wires for filtering water streams. BACKGROUND [0002] Rainwater downspouts, curbside storm water runoff collectors, and similar water conduits share a common purpose: removal of water from where it is undesired, be it the roof of a building, a city street, a storm basin, or the like. All such conduits allow a volume of water to pass therethrough. Leaf litter, sand, dirt, grit, and other debris can accumulate within such conduits and clog them, rendering them ineffective. Equally bad, the poor design of many water conduits allows debris to pass through to downstream channels and, ultimately, the ocean, with a consequent negative environmental impact. [0003] Not surprisingly, much effort and money has been spent devising ways to avoid clogged water conduits and contaminated water streams. Patents have been granted for inventions designed to filter water at curbside storm drains (U.S. Pat. No. 6,231,758 to Morris et al.), to treat water in a horizontal passageway (U.S. Pat. No. 6,190,545 to Williamson), to create temporary stream filtration systems (U.S. Pat. No. 4,297,219 to Kirk et al.), to remove downspout debris (U.S. Pat. No. 5,985,158 to Tiderington), and to shield rain gutters on the eaves of a building (U.S. Pat. No. 4,435,925 to Jefferys). [0004] However, with respect to downspouts and storm water systems, the prior art has several shortcomings. Among other things, it is difficult to devise a system that both operates under high flow and effectively filters out small particulate matter and other debris. This is because a filter element that accommodates large flow must also be designed with large spacing to suit the large flow. However, large spacing allows medium to small particulates and waste to pass through unfiltered. Conversely, a filter element designed to trap small particulate matter typically obstructs flow. An ideal water runoff filter would be both capable of passing high flow therethrough and removing small waste and debris. [0005] Accordingly, there remains a need for a filter system for removing debris from a water stream using a filter element that is amenable to high volume flow, capable of removing or trapping waste the size of or even smaller than the size of the gap used for the filter and, preferably, self-cleaning. SUMMARY [0006] The present invention integrates a Coanda screen (sometimes called “Coanda-effect” screen) into water collection systems such as downspouts, storm runoff collectors, sewer drains, and similar conduits and receptacles. An exemplary embodiment includes retrofitting an existing downspout section (or customizing a new downspout section) with a Coanda screen to provide a downspout with a highly efficient filter for removing debris from a stream of water. Depending on the water flow rate and the size of the debris encountered, different screen sizes and different screen mounting angles may be selected to accommodate the same. Filtered water can pass through the screen, while debris is retained by the Coanda screen and then collected in an optional retaining basket. [0007] In another embodiment, a curbside inlet to a storm drain is fitted with a Coanda screen. The screen is mounted between a raw inlet basin and an outlet basin. Filtered water is allowed to pass over the screen and then fall through the screen into the outlet basin, which then flows onward via an outlet pipe. Captured debris and waste are allowed to fall into a retention basin. To remove waste and debris more effectively, a retaining basket is used. When full, the basket can be lifted out of the curbside inlet and emptied. [0008] In yet another embodiment, there is provided a downspout filter assembly comprising a housing comprising an inlet, and outlet, an interior cavity, and an entrance to the interior cavity; a filter comprising a plurality of wedge wires mounted in the interior cavity of the housing having a portion positioned directly subjacent the inlet; and at least one media pad positioned under the filter for scrubbing water before it exits the outlet. [0009] The present invention may also be practice by providing a downspout filter assembly comprising a housing comprising an inlet, and outlet, an interior cavity, and at least one surface positioned along a first plane; a Coanda filter positioned inside the interior cavity at an angle to the first plane; one or more media pads positioned in the interior cavity at a position below the Coanda filter. [0010] In still yet another aspect of the present invention, there is provided a downspout filter assembly comprising a housing comprising an inlet, an outlet, and an interior cavity; a pair of rails attached to two sections of the interior cavity; at least one removable container positioned on the pair of rails; a media pad positioned in the at least one removable container or below the at least one removable container; and a filter comprising a plurality of wedge wires mounted in the interior cavity in a position above the media pad. [0011] Yet in another aspect of the present invention, there is provided a downspout filter assembly comprising a housing comprising an inlet, and outlet, an interior cavity, and an entrance to the interior cavity; a filter comprising a plurality of wedge wires mounted in the interior cavity of the housing having a portion positioned subjacent the inlet; and at least one media pad positioned subjacent the filter for scrubbing water before it exits the outlet. [0012] The present invention may also be practiced by incorporating a downspout filter assembly comprising a housing comprising an inlet, and outlet, an interior cavity, and at least one surface positioned along a first plane; a Coanda filter positioned inside the interior cavity at an angle to the first plane; at least one media pad positioned in the interior cavity at a position below the Coanda filter. [0013] Yet, it is also within the spirit and scope of the present invention to incorporate a downspout filter assembly comprising a housing comprising an inlet, an outlet, and an interior cavity; a pair of rails attached to two sections of the interior cavity; at least one removable container positioned on the pair of rails; a media pad positioned in the at least one removable container or below the at least one removable container; and a filter comprising a plurality of wedge wires mounted in the interior cavity in a position above the media pad. BRIEF DESCRIPTION OF THE DRAWINGS [0014] These and other features of the invention will be better understood when considered in conjunction with the accompanying drawings, wherein like part numbers denote like or similar elements and features, and wherein: [0015] FIG. 1 is a side elevation view of a downspout with a Coanda screen in accordance with practice of the present invention; [0016] FIG. 2 is a front elevation view of the downspout of FIG. 1 ; [0017] FIG. 2A is a partial cross-sectional view of a deflector plate; [0018] FIG. 3 is a cross-sectional view of the downspout of FIG. 2 , taken at line 3 - 3 ; [0019] FIG. 4 is an enlarged view of the Coanda screen attached at its downstream end to the downspout; [0020] FIG. 5 is another enlarged view of the same Coanda screen attached at its upstream end to the downspout; [0021] FIG. 6 is an enlarged view of a section of the Coanda screen of FIGS. 4 and 5 ; [0022] FIG. 6A is a depiction of a concave screen surface; [0023] FIG. 7 is a side elevation view of a storm drain system in accordance with practice of the present invention; [0024] FIG. 8 is a top plan view of the storm drain system of FIG. 7 ; [0025] FIG. 9 is a partial cross-sectional view of the storm drain system of FIG. 7 taken at line A-A; [0026] FIG. 10 is a front elevation view of an alternative downspout with a Coanda screen; [0027] FIG. 11 is a side elevation view of the embodiment of FIG. 10 ; [0028] FIG. 12 is a front elevation view of another alternative downspout embodiment with a Coanda screen; [0029] FIG. 13 is a side elevation view of the embodiment of FIG. 12 ; [0030] FIG. 14 is a semi-schematic partial transparent, exploded, and perspective view of an alternative downspout filter assembly provided in accordance with aspects of the present invention comprising a plurality media pads for scrubbing filtered water; [0031] FIG. 15 is a semi-schematic partial transparent, exploded, and perspective view of the alternative downspout filter assembly of FIG. 14 ; and [0032] FIG. 16 is a semi-schematic side view and partial cross-sectional view of the alternative downspout filter assembly of FIG. 14 mounted on a structure and assembled to an upper and a lower downspout section. DETAILED DESCRIPTION [0033] In accordance with the present invention, a highly effective filter system for a rain water downspout, sewer inlet, curbside storm water drain, or similar water runoff conduit or receptacle is provided. A preferred embodiment of an improved downspout 10 is shown in FIG. 1 . The downspout is mounted to an exterior wall 12 of a building by conventional mounting means (not shown), such as welds, adhesives e.g., glue, cement, mortar, etc.), mechanical fasteners (e.g., rivets, bolts, screws, clamps, bands, straps, etc.), and other means known in the art. The downspout 10 includes a Coanda screen 20 mounted within a portion 40 of the downspout, referred to herein as the an “upgraded downspout portion” or “upgraded downspout section”. The screen is accessible via a downspout opening 60 in the upgraded downspout portion. Water that flows into the downspout from a gutter (not shown) is filtered as it passes through the Coanda screen. Debris caught by the screen can slide out of the downspout opening into an optional retaining basket 80 mounted outside of and below the downspout opening. Effluent from the downspout empties into a splash guard or basin 100 which, preferably, is seated on a concrete slab 102 . Alternatively, the downstream end of the downspout is coupled to an underground header or a drain line (not shown) running to a main sewer or storm drain. The Coanda screen, upgraded downspout portion, retaining basket, and other features are described below in more detail. [0034] An existing downspout can be upgraded or retrofitted by cutting out or otherwise removing a portion thereof, and installing an upgraded downspout portion or section 40 therein, using a slip joint, welds, adhesives, mechanical fasteners, or other conventional attachment means. Alternatively, an entire downspout can be fabricated as such and installed as part of a rain water removal system that includes one or more gutters and mounting hardware. In either case, the improved downspout provides a path for funneling water from a roof (or a deck, mezzanine, or other surface) to grade (e.g., street level) or to a storm water runoff drain or a main sewer line. Effluent from the downspout eventually flows to a storm drain or sewer system and then to the ocean, in some cases via a water treatment facility. [0035] The downspout 10 is preferably constructed of stainless steel, galvanized steel, aluminum, plastic, or some other durable and water-resistant material, and has an interior and an exterior, and a cross-sectional shape that is generally rectangular. Alternatively, the downspout can have a generally circular cross-section or other desired geometry. In an exemplary embodiment, the downspout 10 is physically attached to an exterior wall 12 of a house or a building by any conventional means, such as downspout bands (not shown) anchored to the exterior wall. Water falling into the downspout passes into the upgraded downspout section 40 to the Coanda screen 20 . The Coanda screen 20 allows water to pass through, but traps waste and debris behind. [0036] A Coanda screen acts by a shearing action referred to as the “Coanda effect,” which is discussed below in greater detail. In FIG. 1 , the Coanda screen 20 has an upper surface 22 , a lower or underside surface 24 , a first (upstream) end 26 , a second (downstream) end 28 , and left and right sides, and is made of a plurality of wedge-shaped wires 30 . Additional details of the wires' shape and relative orientation is provided below. [0037] The Coanda screen 20 is mounted at an angle within the upgraded downspout portion 40 , with the upstream end 26 of the screen elevated relative to the downstream end 28 of the screen. As shown in FIG. 1 , the upgraded downspout portion 40 has four walls—front 46 , back 47 , left 48 , and right 49 —and has substantially the same shape and dimensions as the remainder of the downspout. The Coanda screen is affixed within the upgraded downspout portion by, e.g., securing the upstream end 26 of the screen to the back wall 47 of the upgraded downspout portion, and the downstream end 28 of the screen to the front wall 46 of the upgraded downspout portion. So installed, the screen is seen to form an angle θ (theta) with the back wall. In practice, it has been found that best results are achieved when θ has a value of about 15 to 50 degrees, more preferably, about 20 to 45 degrees. [0038] To ensure that a substantial portion of the water entering the downspout is filtered, it is preferred that the screen have a large enough area to make contact with all four walls 46 - 49 of the interior of the downspout housing. Alternatively (or, in addition), one or more baffles are mounted within the downspout to divert the flow of water toward the screen. In FIG. 1 , two baffles 52 and 54 are shown secured to the front wall 46 and side wall 48 , respectively, of the upgraded downspout portion at a position above the downspout opening 60 , and oriented such that the baffle projects toward the Coanda screen 20 . The side baffle 54 comprises a front plate 58 and a rear plate 59 . The rear plate 59 is attached to the side wall 48 by known methods, including welding, adhesive, mechanical fasteners and the like while the front plate 58 protrudes from the side wall 48 . The front plate 58 protrusion acts as a diverter to divert water that clings to the side wall towards the screen 20 . Similar attachment and configuration is discussed below for a deflector plate ( FIG. 2A ). [0039] In FIG. 3 , two side baffles 54 and 56 are shown, secured to the left 48 and right 49 side walls of the downspout. Fewer or greater numbers of baffles can be mounted within the downspout to provide optimal diversion of water toward the Coanda screen. For example, the back wall 47 can also be configured to include a baffle. This may be desirable where the upstream end 26 of the screen is not recessed within the surface of the back wall 47 . The presence of such a baffle ensures that water cannot bypass the screen. The baffles can be attached to the inside walls of the downspout using any conventional means, including, without limitation, welding, adhesives, and mechanical fasteners. [0040] The downspout opening 60 provides access to the Coanda screen for maintenance and cleaning. Although the screen is self-cleaning, occasionally debris may become trapped within the downspout or (rarely) wedged between the wires 30 that form the screen. Access to the screen is facilitated by providing the downspout opening 60 with appropriate dimensions relative to the screen 20 . A preferred downspout opening 60 has a width approximately 50-100% of the interior width of the downspout, and a height approximately 33-75% of the vertical profile of the screen 20 , the latter being measured at the wall opposite the downspout opening (the back wall 47 in FIG. 1 ). The downspout opening 60 is located intermediate the upstream and downstream ends of the downspout 10 , but not necessarily equidistant from both ends. [0041] A retaining basket 80 to catch debris caught by the Coanda screen is mounted to the downspout just below a debris deflector plate (further discussed below), using conventional means, such as welding, adhesives, mechanical fasteners, and the like. In an exemplary embodiment, the retaining basket 80 comprises a tightly woven screen made of steel, aluminum, or other weather-resistant material. Debris that does not freely fall into the retaining basket 80 (i.e., debris that clings to the filter due to friction) is eventually pushed out the downspout opening 60 by additional water flowing from the gutter. Water clinging to debris caught in the retaining basket 80 can drip onto the splash guard 100 by passing through the holes of the retaining basket 80 . Alternatively, if an underground header is used to connect with the downspout, water that passes through the retaining basket can be caught by a collector (not shown) mounted beneath the retaining basket, and channeled to the header. [0042] In an exemplary embodiment, the downspout is also equipped with an external debris deflector plate 110 . The debris deflector plate is mounted just below the downspout opening 60 along the external surface of the front wall 46 , just above the retaining basket 80 . The debris deflector plate covers any space between the downspout 10 and the retaining basket 80 , and ensures that debris exiting the downspout opening does not fall between the downspout and the retaining basket. [0043] In an exemplary embodiment shown in FIG. 2A , the deflector plate 110 includes a front plate section 112 configured to deflect debris into the retaining basket, and a rear plate section 114 configured to be attached to the downspout. In an exemplary embodiment, the deflector plate 110 , like the downspout itself, is made of a durable, weather-resistant material, such as aluminum, plastic (e.g., polyvinyl chloride and unplasticized vinyl), galvanized steel, and the like. The deflector plate can be mounted to the downspout by known methods, including welding, adhesives, mechanical fasteners, and so forth. [0044] Reference is now made to FIG. 4 , which is an enlarged view of Detail A indicated in FIG. 1 . The downstream end 28 of the Coanda screen is shown secured to the downspout front wall 46 by an upper bracket 70 and a lower bracket 72 , without obstructing the flow of debris from the upper surface of the Coanda screen into the retaining basket. The two brackets are attached to the downspout by conventional means, such as welding, adhesives, mechanical fasteners, and so forth. Preferably, the upper bracket is substantially flush with the outer wall of the downspout housing at the bottom of the downspout opening. [0045] Similarly, FIG. 5 provides an enlarged view of Detail B indicated in FIG. 1 . The upstream end 26 of the Coanda screen 20 is shown secured to the downspout back wall 47 by upper 74 and lower 76 brackets. However, in addition to securing the upstream end of the screen 20 , the upper bracket 74 also serves to divert water flow along the back wall 47 of the downspout to the screen. Although not shown, similar upper brackets may also be mounted around the entire perimeter of the screen so that any water flow along any of the four downspout walls is diverted toward the screen. The two brackets 74 , 76 are attached to the downspout by conventional means, such as welding, adhesives, mechanical fasteners, and so forth. [0046] FIG. 6 shows an exemplary cross-sectional view of the Coanda-effect screen 20 . The screen comprises a plurality of individual wedge wires 30 , which are parallel to one another and separated from each other by a gap or a spacing 32 . The individual wedge wires 30 are held together in the indicated arrangement by welding two or more backer rods (not shown) to the base portions 34 of each individual wedge wire 30 . Coanda screens are commercially available in several standard sizes. Generally, the difference in screen selection relates the width, height, and tilt angle 36 of the wedge wires, and the gap spacing 32 between the wedge wires. In addition, the Coanda screen may be ordered with an overall concave shape. As shown in FIG. 6A , the term “concave” implies a curved contour when viewed with respect to the upper surface 22 of the screen 20 . When a concave screen is specified, the concave shape has the effect of increasing the tilt angle of the individual wedge wires. This in turn allows the leading (upstream) edge 38 of the wedge wire to shear a greater amount of the water, provided that all other parameters are unchanged. In an exemplary embodiment, the Coanda screen has a gap spacing of about 0.1 to 1.0 mm and a tilt angle of about 3 to 15 degrees, with a radius (“R”) of concavity of from about 6 inches to infinity (when R=infinity, the screen is flat). Alternatively, other screen parameters may be used, taking into account the size of the debris likely to be encountered, the anticipated water flow rate and volume, and so forth. [0047] Coanda screens are available from a number of manufacturers and retailers, including on-line retailers such as www.hydroscreen.com, www.iohnsonscreens.com, and www.eni.com/norris/default.html. The screen is described in an article entitled “Hydraulic Performance of Coanda-Effect Screens” by Tony Wahl for publication in the Journal of Hydraulic Engineering, Vol. 127, No. 6, June 2001, the entire contents of which are expressly incorporated herein by reference as if set forth in full. [0048] As explained by Wahl, the Coanda effect is a tendency of a fluid jet to remain attached to a solid flow boundary. As shown in FIG. 6 , when water 130 flows across the screen 20 from the upstream direction, it tends to remain attached to the upper surface of the screen as it travels in the direction of the downgrade 79 . At a given point along the screen, the water has a thickness “X”. As water 130 flows down the screen, its thickness X is sheared by the leading edge 38 of each individual wedge wire 30 . The sheared water is then redirected approximately tangentially 120 to the direction of the original flow due to the contour of the wedge wire 30 . Thus, different wedge wire contour will cause water to be redirected differently. This shearing action is repeated as water traverses down the screen along the direction of the downgrade 79 . Water is sheared as it travels over other wedge wires 30 . After each layer of water is sheared, it is caused to flow along one of several filtered water paths 120 a , 120 b , 120 c , 120 d , etc. The thickness of the water stream gets progressively smaller as the downstream end of the screen is approached, and the flow of water appears to slow to a mere trickle, or even drop off altogether. [0049] This phenomenon is used to great effect in the present invention. Debris-laden water is effectively filtered at the Coanda screen. Any debris that does not fall into the retaining basket 80 during rainfall eventually dries on the screen, and either falls into the basket later, or can be manually removed via the downspout opening 60 . [0050] In an alternate embodiment of the invention shown in FIGS. 7-9 , an effective filter system for removing debris from a storm water runoff collector is provided. The runoff collector 200 comprises a Coanda screen 20 installed between a raw inlet basin 210 and an outlet basin 220 . As before, the screen 20 filters incoming water while trapping debris, but the source of water is a raw stream 212 , from an inlet 214 , and the effluent is a discharge stream 222 for an outlet line 224 . [0051] In an exemplary embodiment, the Coanda screen 20 is mounted between a first weir 230 and a second weir 240 . The screen has a concave surface, with a radius of from about 6 inches to infinity, and is outfitted with an acceleration plate 250 . The acceleration plate 250 is a metal plate of hardened steel, such as stainless steel and the like, mounted to the upstream end 26 of the screen. [0052] The acceleration plate has a width of approximately 2 inches or higher depending on the size of the storm drain system. When water flows from the raw inlet basin 210 over the weir 230 , it has a relatively low flow velocity. If water is allowed to flow over the screen 20 without first having the necessary flow velocity, the screen's ability to filter out debris will greatly decrease. The acceleration plate provides a vertical drop of about 2 inches or higher, allowing in-coming water to build up velocity before it contacts the first wedge wire on the screen. [0053] Debris caught by the Coanda screen can slide into a retention basket 260 located within a retention basin 262 . In an exemplary embodiment, the retention basket 260 is equipped with a handle 264 , which allows the retaining basket to be lifted out of the basin, whereupon the debris can be discarded. The basket 260 may be a conventional basket and may be constructed out of medium to large steel wire mesh. Due to its size, it may be necessary to lift the basket with a crane or a flit truck having a lift. [0054] In an alternate embodiment of the upgraded downspout 10 shown in FIGS. 10 and 11 , a tapered front wall 46 and a modified back wall 47 having a tapered back wall section 270 is provided. The tapered front wall 46 and tapered back wall section 270 allow the screen 20 to be moved forward in the direction of the retaining basket 80 , and provide clearance for the installation of an acceleration plate 250 . In an exemplary embodiment, additional wall mounted baffles for diverting water toward the screen 20 are not necessary, as the screen is positioned directly below the incoming flow path and even extends past the incoming path. This screen configuration allows all or substantially all of the incoming flow to flow through the screen. [0055] In another alternate embodiment of the upgraded downspout 10 , shown in FIGS. 12 and 13 , an optional hinged cover 272 is provided over the downspout opening 60 of an enlarged upgraded downspout 10 . The enlarged upgraded downspout 10 is slightly larger than a conventional or existing downspout section, but has a much larger depth (the distance between the front wall 46 and the back wall 47 ), e.g., on the order of about 1.3 to 3 times deeper. This allows the enlarged upgraded downspout to accommodate a much larger screen 20 than a standard size upgraded downspout. This in turn, allows the much larger screen 20 to filter substantially all of the incoming flow without the need for wall mounted baffles. However, in the embodiment of FIGS. 10-13 , wall mounted baffles, such as baffles 52 and 54 , can be used. [0056] Referring now to FIG. 14 , a semi-schematic partial perspective-partial transparent view of an alternative downspout filter assembly 280 provided in accordance with aspects of the present invention is shown. In one exemplary embodiment, the downspout filter assembly 280 comprises a housing 282 , having a downspout inlet 284 , a downspout outlet 286 , an interior cavity 288 comprising a plurality of filter components, and an optional door cover 290 . The filter assembly 280 is configured for use in a section of a downspout installed on a structure, such as a parking structure, a building, or other structures that require a water gutter system. As readily apparent, a section of a downspout is to be replaced by the downspout filter assembly 280 . When replaced, an upper or upstream section of the downspout is to be coupled to the downspout inlet 284 by conventional means and a lower or downstream section of the downspout is to be coupled to the downspout outlet 286 also by conventional means. Alternatively, the downspout outlet 286 may be coupled directly to a drain or remain opened to drain over a surface drain. The filter assembly 280 is adaptable in that it may be installed in an existing downspout section or be part of a new downspout installation. [0057] In one exemplary embodiment, the filter components comprise a Coanda filter 20 , a collection container or a debris container 292 , an outlet container 294 , and a filter medium 296 , which may comprise one or more media pads 298 a , 298 b for one or more different filtering functions. Alternatively, a filter comprising a plurality of wedge wires may be used to filter debris and other contaminants, with tilted wedge wires or Coanda screen being more preferred. Screen with wedge wires are commercially available, for example, through Goel Engineers in India, which has the following website: http://www.goelka.com/wws.htm. The filter components are housed inside the interior cavity 288 of the housing 282 and are closed therein by a door cover 290 abutting the housing flange 300 and a latch 302 , which may embody a key lock or other prior art means for securing the door to the flange. In one exemplary embodiment, the door cover 290 may comprise two or more door sections and may include a gasket 304 for providing a relatively tight seal as compared to when no gasket is used. The gasket may include any prior art gaskets and may adhere to the door cover by adhesive. The door cover 290 is connected to the housing 282 via one or more conventional hinges or fasteners. For venting, one or more vent holes 291 may be incorporated on one or more sides of the housing 282 . If the vent holes 291 are incorporated, they are preferably positioned at a location with minimal water splash. [0058] The housing 282 may comprise a number of different shaped configuration, such as a rectangular shaped box, a square shaped box, or a cylindrical shaped box, with a rectangular shaped box being more preferred. The housing 282 may be made from a number of metallic sheets, such as stainless steel sheets, tin sheets, sheet metal, and zinc coated sheet metal with stainless steel sheets being more preferred. Alternatively, plastic, fiberglass, or synthetic plastic materials may be used. [0059] Referring to the referenced length L, height H, and width W of the housing 282 , in a preferred embodiment, the filter assembly 280 is mounted along a lengthwise direction L against a structure 348 ( FIG. 16 ). To facilitate attachment along the lengthwise direction L, the housing 282 includes a pair of mounting flanges 306 a , 306 b , one along the upper housing section and one along the lower housing section. Alternatively, the filter assembly 280 may be mounted along the width direction W by incorporating the two mounting flanges 306 a , 306 b along the width edge of the upper and lower sections of the housing 282 . [0060] Also shown in FIG. 14 is an optional final treatment filter media 308 . The final filter media 308 , when incorporated, is to be positioned in a sump 310 , which is the space defined by the area under the two containers 292 , 294 and the bottom of the housing 282 . The media pads 298 a , 298 b and the final filter media 308 , when incorporated, are configured to remove organic compounds, toxic metals, particulates, and other undesirable contaminants. The various filter medium may comprise, for examples, e.g., activated carbon, Rubberizer® polymers and particulate products, metal absorbing soy bean hulls, peat, siliceous rocks, activated silica, Miex resins, and potassium permanganate pellets. Depending on the contaminants to be removed, the particular media to be used can be selected accordingly. As an alternative or in addition to the absorbent pads, pelletized hypochlorite or other formulations of chlorine may be used as a media to kill undesirable bacteria, such as E. coli bacteria. Still alternatively, where electricity power is available, the housing may be equipped with UV (ultraviolet) lamps to provide ultraviolet radiation to also kill undesirable bacteria. Conventional mounting means for mounting UV lamps in a wet environment would be required if UV lamps are incorporated. [0061] Broadly speaking regarding operation of the downspout filter assembly 280 , during a rain storm or cleaning operation in which water is used, water is directed down a downspout, flows through the downspout inlet 284 , is filtered by the Coanda filter 20 , in which solids and other suspended contaminants are filtered by the filter 20 and are trapped along the upper surface of the filter and the passes through to the outlet container 294 . The trapped solids and other suspended contaminants are subsequently collected in the collection container 292 , either by being pushed into the container 292 by later trapped solids, gravity, or by a service technician. The filtered water that passes through the filter 20 is additionally filtered by the filter medium 296 positioned in the outlet container 294 and by the final filter media 308 located in the sump 310 , if incorporated. Water then flows out the filter assembly 280 via the downspout outlet 286 . [0062] Referring now to FIG. 15 in addition to FIG. 14 , an exploded perspective view of the downspout filter assembly 280 provided in accordance with aspects of the present invention is shown. The filter 20 incorporated herein is similar to the filter described above with reference to FIGS. 1-6A , and, in addition, may include both wedge wires and tilted wedge wires. A baffle or plate 312 , which may embody a rectangular metallic or plastic plate, is connected to the lower edge of the filter 20 with a second plate 314 connected to the filter 20 at its underside to form an inverted “V” shaped ledge 316 . When assembled, the ledge 316 is adapted to receive or rest on the support rim 318 of the collection container 292 and the support rim 320 of the outlet container 294 (See, e.g., FIG. 14 ) while the upper filter section rests against the back wall of the housing 292 . Optionally, latching mechanisms may be used to removably fasten the filter inside the housing using conventional fastening means. [0063] The containers 292 , 294 incorporated herein may be made of a metallic mesh material for durability, such as a stainless steel mesh material. However, rubber or hard plastic containers may also be incorporated where desired. In one exemplary embodiment, the mesh size for the collection container 292 should be smaller than the mesh size for the outlet container 294 to prevent or minimize small solids collected in the collection container 292 from escaping through the plurality of openings provided by the mesh. Obviously, the mesh size for both containers can be similarly sized for ease of manufacturability. Handles 322 may be added to the containers 292 , 294 for ease of handling the containers during cleaning or other maintenance operation when the containers are removed from the interior cavity 288 . [0064] The outlet container 294 and the media pads 298 a , 298 b should be sized such that the perimeter of the pads contact the interior surface of the outlet container 294 when the media pads 298 a , 298 b are placed therein ( FIG. 16 ). As readily apparent, this configuration ensures that water entering the outlet container 294 will pass through the media pads 298 a , 298 b before it exists the downspout outlet 286 . The pads 298 a , 298 b are positioned in the outlet container by stacking and resting them directly on the base of the container 294 . Optionally, a treatment pad separator (not shown) may be placed in the container first before the first media pad is added with additional treatment pads to be placed in between a set of media pads. The overall dimensions of the containers 292 , 294 , media pads 298 a , 298 b , and other components of the filter assembly 280 can vary depending on the volume throughput of the particular downspout, which can vary from installation to installation. In a preferred embodiment, the filter assembly 280 and all its components should be sized to handle about 110% to about 125% of the maximum expected flow rate of the particular downspout section [0065] In one exemplary embodiment, an exit flow deflector 324 comprising a base 326 and two side walls 328 each comprising a rail or a flange 330 are incorporated in the filter assembly 280 . The base 326 preferably has a surface that is sloped about 10-30 degrees from the surface of the flanges 330 for directing flow entering the sump area 310 , as further discussed below. The flow deflector 324 should have a length and a width approximately that of the outlet container 294 . The flow deflector 324 is preferably made from a rigid material, such as a sufficiently gauged metallic sheet or a hard plastic. [0066] In an exemplary embodiment, a main baffle or deflector plate 332 may be incorporated in the filter assembly 280 . As further discussed below, the main baffle 332 , if desired, may be installed subjacent or behind the filter 20 so that as water passes through the filter 20 , it is deflected away from the back side wall 334 of the housing 282 by the main baffle. As readily apparent, this arrangement allows the baffle to direct water away from the housing wall so that the water can then flow through the outlet container 294 where it could be scrubbed or cleaned by the media pads 298 a , 298 b . When installed, the surface of the main baffle 332 should be angled about 5-30 degrees relative to the back sidewall 334 . Rivets, spot welding, brackets, fasteners, or other conventional attachment means may be used to attach the flange section 336 of the main baffle 332 to the back sidewall 334 . [0067] Two brackets or rails 338 , one on an outside sidewall 340 and one on an inside sidewall 342 , are incorporated for placement of the exit flow deflector 324 and the two containers 292 , 294 thereon. The rails 338 , which resemble right-angle brackets, provide two ledges that protrude from the two sidewalls 340 , 342 . The ledges are configured to support the deflector 324 and the two containers 292 , 294 when the same are placed thereon. More particularly, the rails 338 support the deflector 324 and the two containers 292 , 294 by first placing the two flanges 330 of the deflector 324 on the rails 338 and then placing the containers 292 , 294 over the rails, with the outlet container 294 preferably placed directly over the deflector 324 (See, e.g., FIG. 1 ). The sump 310 is an area defined in part by the base of the containers 292 , 294 when over the same are placed on the rails 338 . [0068] A containment dam 342 is positioned at the entrance 344 to the interior cavity 288 of the housing 282 . The containment dam 342 preferably contacts and forms a seal with the two side walls 340 , 342 and the base wall 346 of the housing. The containment dam 342 preferably extends about ⅕ to about ⅓ of the height of the entrance 344 , and should at least be level with or rises above the surface of the rails 338 . The containment dam 342 may be attached to the housing using any prior art methods, including forming the dam by bending a portion of one or more of the sidewalls and then using welding or epoxy to seal the seam. [0069] Referring now to FIG. 16 in addition to FIGS. 14 and 15 , a semi-schematic side view and partial cross-sectional view of the downspout filter assembly 280 is shown mounted on a structure 348 . As previously discussed, the filter assembly 280 may be mounted by fastening the upper and lower mounting flanges 306 a , 306 b to the structure using a plurality of fasteners 350 . The inlet 284 and outlet 286 are strapped or clamped to the upper downspout section 352 and lower downspout section 354 , respectively, using fastening clamps or straps 356 in combination with pliant wrappers 358 . The pliant wrappers can embody rubber sheets or other equivalent materials. However, any prior art coupling means may optionally be used to couple the inlet and outlet of the system 280 to the upper and lower downspout sections. [0070] As shown, when water 360 enters the downspout assembly 280 via the inlet 284 and into the interior cavity 288 , the water makes contact with the filter 20 . As previously discussed, debris and other solids carried by the water 360 are then trapped by the filter 20 along the upper surface 22 of the filter. The solids and the debris are then pushed by the stream of incoming water and incoming solids, and/or by gravity, and fall into the collection container 292 . Water, however, passes through the filter 20 to the underside 24 of the filter in the direction of the main deflector plate 332 . During normal flow, water flows in a downward direction towards the outlet container 294 , where it is then cleaned or scrubbed by the media pads 298 a , 298 b before being deflected again by the exit flow deflector 324 . The exit flow deflector 324 channels the water over the final filter media 308 where it is further cleaned or scrubbed before existing the housing 292 via the outlet 286 . [0071] As readily apparent, the media pads 298 a , 298 b , 308 may be eliminated, replaced with other media pads, or used in combination with additional media pads depending on the desired outcome and/or on environmental regulations. When media pads are used, treatment pad separators 362 may be used to separate the media pad from an adjacent pad or from a solid surface, such as the bottom of the housing. The separators 362 may be made from nylon or plastic webbing sheets such as spun-bonded webbing sheets, steel mesh, porous media, or other material to provide gaps or passages for the water flow. [0072] In an exemplary embodiment, a passage 364 is provided internally of the interior cavity 288 for bypassing water 360 around the media pads 298 a , 298 positioned inside the outlet container 294 . This passage 364 is located intermediate the lower edge of the main deflector 332 and the top of the outlet container 294 proximate the back sidewall 334 of the housing 292 . In the event the media pads 298 a , 298 b are clogged and water backs up in the outlet container 294 , water can escape through the passage 364 to then flow out of the housing 292 via the outlet 286 . [0073] Although the invention has been described with reference to preferred and exemplary embodiments, various modifications can be made without departing from the scope of the invention, and all such changes and modifications are intended to be encompassed by the appended claims. For example, an upgraded downspout section can be manufactured as a separate unit and installed as a new downspout. Other materials than those described herein can be used to make the various components of the apparatus described. Changes to the way the baffles are installed, the way they are shaped, the way the deflector plates are installed, and the way the screens are installed within the housing can be made. Other alterations and modifications may be made by those having ordinary skill in the art, without deviating from the true scope of the invention.	A debris-filtering downspout and other water runoff conduits and receptacles are disclosed, and include a screen mounted within a conduit, a culvert, a storm water conveyance or secured to a water collection basin. The screen provides high water throughput and is self-cleaning while effectively filtering debris contained in an incoming water stream. Optionally, media pads may be included to further scrubbed the water before it exits the downspout assembly.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of co-pending U.S. patent application Ser. No. 10/085,333, filed on Feb. 28, 2002 and published as U.S. Patent Publication No. U.S. 2003/0159381 A1 on Aug. 28, 2003, the disclosure of which is hereby explicitly incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to post-frame buildings, and, more particularly, to a column for use in the construction of a post-frame building. [0004] 2. Description of the Related Art [0005] Typical post-frame buildings include a series of wooden columns set into the earth and positioned in a geometric configuration generally corresponding to the desired perimeter of a post-frame building. A distal end of each column is set into the earth, while a proximal end is affixed to a truss. Note that for the purposes of this document, the reference point with respect to the use of the words “distal,” and “proximal” is taken as the highest point on the post-frame building in question. The body of each column is joined to an adjacent column via a number of generally horizontally placed planks. Such a horizontal placed plank positioned adjacent the earth is generally referred to as a skirt board, while a horizontal plank joining adjacent columns positioned a distance from the earth is generally referred to as a girt. After the skirt board and girts are affixed to the columns, a siding member is attached to the skirt board and girts to define an exterior of the post-frame building. Similarly, adjacent trusses are joined together by wooden planks referred to as purlins. Generally, purlins are positioned substantially transverse to the trusses. A roofing member is affixed to the trusses via the purlin to form an exterior roof of the post-frame building. [0006] Typically, to construct a post-frame building, a series of holes are bored into the earth about the perimeter of the building. The depth of these holes can be, e.g., three to five feet, with adjacent holes being placed on, e.g. four to ten foot centers. After the holes are formed, a concrete pad is positioned in the distal most portion of the hole. Generally, the concrete pad comprises a precast concrete pad having a generally cylindrical shape. After each hole receives a concrete pad, a column is set into each hole and the holes are back-filled with, e.g., gravel to maintain the columns in a vertical orientation. Generally, either solid wood columns or laminated wood columns are utilized in post-frame construction. Laminated columns are typically formed of three or more 2×6's or 2×8's positioned side by side to form the column. Both the solid and laminated columns of the prior art which are set into the earth must be treated with a wood preservative to prevent degradation thereof due, e.g., to insect damage, and/or damage from the elements, e.g., moisture. Planting treated wood columns in the ground can, potentially, have an adverse impact on the environment. [0007] What is needed in the art is a column structure which provides excellent resistance to degradation of its mechanical properties from the exposure to the elements which accompanies its placement in the ground, while providing ease of workability to complete construction of the building above ground and which is environmentally friendly. SUMMARY OF THE INVENTION [0008] The present invention provides an improved column for use in the construction of a post-frame building. In accordance with the present invention, a two piece column is utilized in the construction of a post-frame building. The two piece column of the present invention generally comprises a foundation column for placement in the earth, with a proximal end thereof protruding from the earth. The proximal end of the foundation column includes a column bracket for joining the foundation column to a wooden column comprising the second portion of the two piece column of the present invention. The foundation column of the present invention comprises a precast concrete column body having a column bracket affixed to a proximal end thereof. The column bracket includes a plurality of apertures to facilitate affixation of the second portion of the two piece column structure thereto. [0009] In one exemplary embodiment, the column bracket is a generally U-shaped structure having a base with a pair of transverse depending arms extending therefrom. The depending arms of the column bracket are spaced to allow placement of a wooden column there between. The depending arms of the column bracket include a plurality of apertures through which a connector such as, e.g., a carriage bolt can be placed. In use, apertures corresponding to those formed in the depending arms of the column bracket will be formed in the wooden column comprising the second portion of the two piece column of the present invention. The wooden column will then be placed intermediate the depending arms of the column bracket with a carriage bolt traversing the apertures in the column bracket and the wooden column. A nut will then be placed in the distal end of the carriage bolt and securely tightened to affix the wooden column to the column bracket. [0010] In one exemplary embodiment, one or more reinforcing bar(s) is affixed to the base of the column bracket opposite the depending arms of the column bracket prior to casting the concrete foundation column. That is, the depending arms of the column bracket extend transversely from one face of the base of the column bracket, while the reinforcing bar(s) extends transversely from the opposite face of the base of the column bracket. Each reinforcing bar is welded to the base of the column bracket and provides the necessary tensile strength to the foundation column. The reinforcing bars described in the detailed description portion of this document comprise steel reinforcing bars, however, any suitable material for providing the requisite tensile strength to the concrete foundation columns disclosed herein may be utilized in accordance with the present invention. The reinforcing bars utilized in accordance with the present invention can be placed in differing configurations as will be further discussed in the detailed description portion of this document. Generally, a plurality of reinforcing bars will be utilized in accordance with the present invention, with the reinforcing bars substantially evenly spaced about a longitudinal axis of the foundation column. [0011] An anchor pin sleeve is secured to and positioned adjacent a distal end of the foundation column. The anchor pin sleeve of the present invention comprises a tubular member having opposite ends allowing access to a hollow interior thereof. In one exemplary embodiment, the anchor pin sleeve is positioned whereby a longitudinal axis thereof intersects a longitudinal axis of the foundation column, with the longitudinal axis of the anchor pin sleeve being substantially transverse to the longitudinal axis of the foundation column. For the purposes of this document, substantially transverse is utilized to describe an arrangement in which a pair of components are perpendicular one to another, or no more than 20° out of perpendicular, i.e., forming the angle of 70° to 110°. [0012] The hollow interior of the anchor pin sleeve is sized to accommodate a anchor pin positioned therein. A anchor pin in accordance with the present invention is a generally cylindrical member having a length greater than the length of the anchor pin sleeve. In one exemplary embodiment, the anchor pin comprises a length of ½″ steel reinforcing bar. While the anchor pin sleeve and anchor pin have been described as a hollow cylinder and a cylindrical member, respectively, these structures can have various cross-sectional geometries, including, e.g., elliptical geometries, oval geometries, or various polygonal geometries. Importantly, the exterior cross-sectional geometry of the anchor pin and the interior cross-sectional geometry of the anchor pin sleeve will be shaped whereby the anchor pin is able to traverse the interior of anchor pin sleeve. [0013] When constructing a post-frame building utilizing the foundation column of the present invention, a anchor pin is positioned in the anchor pin sleeve of the foundation column, with one or both ends of the anchor pin protruding from the anchor pin sleeve. The foundation column is then positioned within a hole in the earth and placed atop a concrete pad positioned in the distal portion of the hole. A flowable concrete mixture is placed in the hole to a depth whereby the protruding portion of the anchor pin is covered, thus forming a concrete collar about the distal end of the foundation column. The anchor pin and concrete collar of the present invention cooperate to resist vertical displacement of a foundation column of the present invention. [0014] The present invention advantageously provides a column for use in the construction of a post-frame building having a distal portion for setting into the earth which distal portion is formed of a material which is resistant to degradation of its mechanical properties from exposure to the elements and which is sufficiently strong to support a post-frame construction including the dead load of the building as well as environmental loads, e.g., wind and snow load experienced by the post-frame building. The column of the present invention further advantageously provides an above ground portion thereof formed of wood to facilitate shaping this portion of the column during construction of a post-frame building and, further, to facilitate affixation of additional components of the building including, e.g., trusses, girts, and skirt boards with the use of well known wooden fasteners such as nails and screws. [0015] A column in accordance with the present invention advantageously provides the requisite resistance to the elements, as well as the strength, and workability needed in the construction of post-frame buildings, without requiring the use of treated lumber to form the column. BRIEF DESCRIPTION OF THE DRAWINGS [0016] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: [0017] FIG. 1 is a cutaway perspective view of a post-frame building in accordance with the present invention; [0018] FIG. 2 is a partial plan view of a post-frame building utilizing a column in accordance with the present invention; [0019] FIG. 3 is a perspective view of one embodiment of a foundation column in accordance with the present invention; [0020] FIG. 3A is a perspective view of an alternative embodiment foundation column in accordance with the present invention; [0021] FIG. 4 is a perspective view of the column connector and reinforcing bar configuration utilized in accordance with an embodiment of the present invention; [0022] FIG. 4A is a perspective view of a column bracket/reinforcing bar configuration in accordance with an alternative embodiment of the present invention; [0023] FIG. 5 is a partial perspective view of the distal portion of the reinforcing bar utilized to construct a foundation column in accordance with one embodiment of the present invention; [0024] FIG. 6 is a sectional view of a foundation column of the present invention taken along lines 6 - 6 ′ of FIG. 3A ; [0025] FIG. 7 is a partial plan view illustrating affixation of a wooden column to a column bracket of the present invention and further illustrating affixation of reinforcing bar to a distal portion of the base of a column bracket in accordance with the present invention; [0026] FIG. 8 is a top plan view of the wooden column/column bracket configuration of FIG. 7 ; [0027] FIG. 9 is a bottom plan view thereof; [0028] FIG. 10 is a perspective view of a column bracket of the present invention. [0029] Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. The exemplifications set out herein illustrate embodiments of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. DETAILED DESCRIPTION OF THE INVENTION [0030] A column constructed in accordance with the present invention is illustrated, e.g., in FIGS. 1 and 2 . As illustrated in FIGS. 1 and 2 , a column of the present invention has a two piece construction including foundation column 26 and wooden column 24 . Foundation column 26 is set in the earth with a proximal end thereof protruding from the earth. Wooden column 24 is affixed to the proximal end of foundation column 26 and extends upwardly therefrom. [0031] Alternative embodiments of foundation column 26 are illustrated in FIGS. 3-6 . As illustrated in FIG. 3 , one embodiment of foundation column 26 includes precast concrete column body 44 having a substantially consistent cross-sectional area with anchor pin sleeve 46 positioned adjacent a distal end of precast concrete column body 44 and column bracket 34 positioned adjacent a proximal end of precast concrete column body 44 . Anchor pin sleeve 46 comprises a hollow cylindrical member sized to accommodate anchor pin 32 ( FIG. 2 ). In one exemplary embodiment, anchor pin sleeve 46 is a ⅝″ inner diameter sleeve. [0032] As illustrated in FIGS. 3, 3A , 4 , and 4 A, as well as FIGS. 7-10 , column bracket 34 is generally U-shaped with depending arms 56 extending from base 54 . Depending arms 56 are substantially perpendicular to base 54 and are spaced whereby column 24 may be positioned intermediate depending arms 56 . Column bracket is formed of steel, e.g., ⅛″ to ½″ steel and can be formed in a variety of ways, including, e.g., creating a pair of substantially 90° bends in a planar piece of stock material using a bending brake press or other suitable metal bending apparatus, welding a pair of L-shaped brackets one to the other, or welding together three discrete pieces comprising the two depending arms 56 and base 54 of column bracket 34 . [0033] In the embodiment illustrated in FIG. 7 , wood column 24 comprises a laminated column formed of three discrete wood planks 52 . In alternative embodiments, wood column 24 comprises a solid wood column. Column bracket 34 in accordance with the present invention can be formed in various sizes to accommodate varying wooden columns 24 of differing sizes and construction, including, e.g., solid wooden columns and laminated wooden columns. In one embodiment, the inner faces of depending arms 56 will be separated by a distance equal to the width of the desired wood column 24 plus ⅛″ to ½″ to facilitate placement of wood column 24 intermediate depending arms 56 and adjacent to base 54 . [0034] FIG. 4 illustrates one configuration of reinforcing bars 42 with respect to column bracket 34 . As illustrated in FIG. 4 , reinforcing bars 42 are substantially evenly spaced about base 54 of column bracket 34 . As illustrated in FIG. 7 , reinforcing bars 42 are affixed to base 54 of column bracket 34 via welds 50 . In the embodiment illustrated in FIG. 7 , reinforcing bars 42 are placed in abutting relationship with a distal face of base 54 and are welded thereto. Various alternative methods of affixing reinforcing bars 42 to base 54 of column bracket 34 may be utilized in accordance with the present invention, including, e.g., forming apertures in base 54 to accommodate placement of reinforcing bars 42 therethrough and subsequently welding reinforcing bars 42 to both faces of base 54 . [0035] Referring to FIG. 4 , reinforcing bar spacers 40 are utilized to maintain the spaced relationship of reinforcing bars 42 . Reinforcing bar spacers 40 are affixed to adjacent reinforcing bars via, e.g., welds and maintain the relative position of reinforcing bars 42 along the length thereof. Reinforcing bar spacers 40 illustrated in FIG. 5 have a length whereby a portion of reinforcing bar spacer 40 extends past at least one reinforcing bar 42 . In alternative embodiments, reinforcing bar spacers 40 maintain the spaced relationship of reinforcing bars 42 and do not extend beyond reinforcing bars 42 . In one exemplary embodiment, reinforcing bar spacers 40 are substantially transversely positioned with respect to reinforcing bars 42 . In one embodiment, reinforcing bar spacers 40 are L-shaped. In this embodiment, only two spacers 40 are required. [0036] FIG. 4A illustrates an alternative embodiment of the reinforcing bar/column bracket configuration of a foundation column of the present invention. As illustrated in FIG. 4A , a pair of U-shaped reinforcing bars 42 a are affixed to the distal face of base 54 of column bracket 34 . In this configuration, U-shaped reinforcing bars 42 a have sufficient structural rigidity to substantially maintain the space apart relationship of the upright portions thereof, i.e., the “arms” of U-shaped reinforcing bars 42 a. [0037] In various exemplary embodiments of the present invention, reinforcing bar is positioned within a foundation column in a configuration in which the reinforcing bar will add tensile strength to every face of the foundation column. In practice, adding tensile strength to the face of a foundation column adjacent the building siding is of the greatest importance, as wind load on the side of a post-frame building can place a significant force on the foundation column, tending to flex a proximal end of the foundation column toward the interior of the building in question. Because reinforcing bar is positioned to add tensile strength to every face of the foundation column, an installer need not be concerned with the proper rotational configuration of a foundation post of the present invention to ensure that reinforcing bar is positioned adjacent the face of the foundation column adjacent the building siding. Generally, a sufficient amount of reinforcing bar to withstand at least an 80 mph wind force is utilized in a foundation column of the present invention. [0038] In construction, reinforcing bars 42 or 42 a will be positioned within a mold along with anchor pin sleeve 46 . A concrete mixture is then poured into the mold and sets to form a complete foundation column 26 or 26 a ( FIGS. 3, 3A ). Generally, foundation columns 26 , 26 a comprise 4000-8500 psi precast concrete columns. Foundation column 26 a of FIG. 3A includes bevels 62 , while foundation column 26 illustrated in FIG. 3 has four substantially continuous sides. As illustrated in FIG. 6 , foundation column 26 a includes a pair of bevels 62 on opposing sides thereof. As illustrated in FIG. 6 , bevel 62 terminate in a base b which is substantially parallel to the face of foundation column 26 a in which bevel 62 is formed. In one exemplary embodiment, base b is 1 to 2 inches long and depth d is ¾-1½ inches. Referring to FIG. 3A , the dimensions of an exemplary foundation columns 26 a are as follows: depth (D) of about 5½-7½ inches, width (W) of about 4⅝-6⅛ inches, height of column body 44 (H 1 ) of about 5 feet, and height of column bracket 34 (H 2 ) of about 12-24 inches. Exemplary foundation columns 26 are formed of similar dimensions. [0039] FIGS. 7-9 illustrate affixation of wooden column 24 to column bracket 34 . As illustrated, e.g., in FIG. 10 , column bracket 34 includes four apertures 48 through which a fastener may be placed. As illustrated in FIGS. 7-9 , one appropriate fastener utilized to affix wooden column 24 to column bracket 34 comprises carriage bolt 58 and nut 60 . As illustrated in FIG. 7 , a pair of apertures are formed through wooden column 24 whereby carriage bolt 58 traverses a first aperture 48 in column bracket 34 , thereafter traverses an aperture in wooden column 24 , and finally traverses a second aperture 48 in column bracket 34 . Nut 60 is thereafter secured to carriage bolt 58 to secure wooden column 24 to column bracket 34 . In the embodiment illustrated in FIGS. 7-10 , a pair of carriage bolts 58 and nuts 60 are utilized to affix wooden column 24 to column bracket 34 . In one exemplary embodiment, apertures 48 are 9/16″ apertures and carriage bolts 56 are ½″ carriage bolts. [0040] To construct post-frame building 10 illustrated in FIG. 1 , a series of holes in the earth are made about the perimeter of building 10 to accommodate concrete pads 28 and foundation columns 26 . Concrete pads 28 are positioned in the distal most region of these holes and foundation columns 26 , with anchor pins 32 positioned through anchor pin sleeves 46 (see, e.g., FIG. 3 ) are positioned within the holes and placed atop concrete pads 28 . Foundation columns 26 are generally positioned with depending arms 56 of column bracket 34 substantially perpendicular to a plane in which siding member 14 will be positioned. With foundation columns 26 substantially vertically positioned, concrete collars 30 are poured. The holes are thereafter back-filled to maintain the vertical position of foundation columns 26 . Columns 24 are affixed to column brackets 34 as described hereinabove and skirt board 22 , girts 20 , trusses 16 , purlins 18 , siding member 14 , and roofing member 12 are assembled to complete the construction of building 10 . Fastening mechanisms including, e.g., screws and nails may be utilized to affix various wooden members of post-frame building 10 as well as siding member 14 and roofing member 12 . [0041] While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within know or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.	A column for use in post-frame construction having a two piece construction in which a first or foundation column portion of the column is set into the earth with a proximal end thereof protruding from the earth. The proximal end of the foundation column includes a column bracket for joining the foundation column to a wooden column comprising the second portion of the two piece column of the present invention. The foundation column of the present invention comprises a precast concrete column. The foundation column of the present invention advantageously resists degradation of its mechanical properties due to environmental influences while providing the necessary strength to support a post-frame building, including, e.g., the environmental loads received by the building. The wood column comprising the second portion of the two piece column of the present invention advantageously provides ease of workability to complete construction of a post-frame building.
You are an expert at summarizing long articles. Proceed to summarize the following text: This application is a continuation of pending U.S. Utility Application Ser. No. 10/601,490, filed Jun. 23, 2003, entitled “MULTI-PROGRAM TROLLEYS AND SWITCHES” which claimed priority from U.S. Provisional Application No. 60/391,791, filed Jun. 26, 2002, entitled “MULTI-PROGRAM TROLLEYS AND SWITCHES.” BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to operable wall systems used to partition larger rooms into smaller rooms and particularly to a track and trolley system wherein the trolleys can be programmed to automatically switch panels to form a desired room layout. 2. Description of the Related Art Operable wall panel systems, also known as movable wall panel systems, are often used to temporarily subdivide large rooms into smaller rooms such as in convention halls, hotels, and the like. These systems typically include an overhead track and trolley suspension system whereby wall panels are moved along the track from a storage area to a wall forming position in the space being subdivided. The track may include a number of switches where turns and/or intersections are provided for moving the wall panels. One difficulty in subdividing an area arises when several wall panels must be moved from a storage area through multiple intersecting track segments to a specific location to form a desired room arrangement. In many instances, each individual panel has a pre-designated position in the final room layout. This is particularly important where the subdivided room arrangement has rooms where the walls are of different colors or differing surface textures which may require some of the panels to have differing features on opposite sides. In these situations, improper placement of the panels could result in mismatches in the final room layout. Previously, the process of subdividing a large space was quite time-consuming requiring that panel placement be closely monitored to achieve the desired result. In order to facilitate the process of directing panels to a pre-determined position, guide plates have been mounted on the track intersections and used to cooperate with diverter elements mounted on the panel trolleys. In operation, the guide plates on the track intersection engage the diverter elements on the wall panel trolleys to direct the wall panel on to the proper track. One such prior design is described in U.S. patent application Ser. No. 09/706,041 filed Nov. 3, 2000 and which is assigned to the assignee of the present invention. In some designs, trolleys have been equipped with diverter elements that extend above the trolley wheels to engage a diverter plate mounted on the under side of a top plate of the track switch in combination with additional diverter elements mounted to a plate laterally extending from the trolley below the wheels, that engage diverter plates mounted to the underside of the bottom plate of the track switch. One shortcoming in these prior designs is in the number of trolley and track switch combinations required to subdivide a large area. In another type of movable wall system, electric switching stations are used to direct or switch wall panels to their appropriate track. The switching station includes a rotatable platter mounted at the intersection of multiple tracks. The platter is electrically operated to rotate between multiple positions connecting different track sections together at each position. One disadvantage of this system is that although it allows numerous track sections to be selectively interconnected to move the wall panels down their proper paths, a person is required to control the movement of the platter. The electric switching systems are also relatively expensive. What is needed is a programmable trolley and track system that automatically directs individual wall panels to a pre-determined position in a layout without an excessive number of switch and trolley designs. SUMMARY OF THE INVENTION The present invention provides a multi programmed track switch and trolley system that automatically routes wall panels between intersecting tracks to a pre-determined or pre-programmed wall-forming position. The track switch section includes selectively positioned guide plates on the upper interior wall of the track switch section. The guide plates engage diverter elements positioned on the trolley to direct wall panels on a particular path through the switch section. Each trolley includes an elongated diverter element or blade laterally displaced from the trolley centerline. The lateral displacement of the diverter blades is variable so as to engage selected guide plates on the track switch sections. The diverter blades are also variable in height to engage or not engage certain guide plates. In addition, the trailing trolleys also include one or more centrally mounted diverter pins which are also variable both in height and lateral displacement relative to the trolley centerline. Through the selection of diverter blade and diverter pin arrangements, trolleys can be paired forming multiple combinations from a set of basic trolley designs. The present invention accomplishes a primary objective of providing a track switch and trolley system that automatically routes individual wall panels of an operable wall system to a pre-determined wall forming location to compartmentalize a large room into smaller rooms without the need for an excessive number of individual trolley and switch designs. The invention accomplishes a further objective of providing a switching system that is automatic, and without the need for human intervention. The invention accomplishes a still further objective of providing a switching system wherein a basic set of trolley and track switch designs can be combined to form a variety of room layouts. The invention accomplishes still another objective of providing a cost effective switching system not requiring electrical power. The invention accomplishes a still further objective of providing a switching system that permits all of the wall panels to be stored in one track storage section without the need for offset switches or flapper panels. BRIEF DESCRIPTION OF THE DRAWINGS The above mentioned and other advantages and objects of this invention, and the manner of obtaining them, will become more apparent and the invention itself will be better understood by reference to the following descriptions of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: FIG. 1 is a diagrammatic top view of an operable wall system using a trolley and track switching system according to the present invention; FIG. 2 is a diagrammatic perspective view of the operable wall system of FIG. 1 ; FIG. 3 is a partial diagrammatic top view of the operable wall system of FIG. 1 wherein the track and track switch sections are shown in additional detail; FIG. 4 is a front view of a lead trolley equipped with a side diverter element in the outermost lateral position for the track switching system of the present invention; FIG. 5 is a right side view of the trolley of FIG. 4 ; FIG. 6 is a front view of a trailing trolley equipped with a side diverter element in the outermost lateral position for the track switching system of the present invention; FIG. 7 is a right side view of the trolley of FIG. 6 ; FIG. 8 is a front view of a lead trolley equipped with a side diverter element in an intermediate lateral position for the track switching system of the present invention; FIG. 9 is a front view of a trailing trolley equipped with a side diverter element in an intermediate lateral position for the track switching system of the present invention; FIG. 10 is a front view of a lead trolley equipped with a side diverter element in the innermost lateral position for the track switching system of the present invention; FIG. 11 is a front view of a trailing trolley equipped with a side diverter element in the innermost lateral position for the track switching system of the present invention; FIG. 12 is a top view of a switch assembly from FIG. 2 , shown removed from the remainder of the track, which serves to direct trailing trolleys to their proper track sections during wall panel stacking; FIG. 13 is a front view, taken along line 13 — 13 in FIG. 12 , of the switch assembly of FIG. 12 ; FIG. 14 is a top view of a switch assembly from FIG. 2 , shown removed from the remainder of the track, which serves to direct lead trolleys to their proper track sections during wall panel stacking; FIG. 15 is a front view, taken along line 15 — 15 in FIG. 14 , of the switch assembly of FIG. 14 ; FIGS. 16–21 are front views showing the lead and trailing trolleys of FIGS. 4–11 entering the switch assembly of FIG. 15 ; FIG. 22 is a top view of a first switch assembly from FIG. 2 , shown removed from the remainder of the track, which serves to direct trolleys to the proper intersecting track sections during movement of the suspended panels in a wall forming direction; FIG. 23 is a rear view, taken along line 23 — 23 in FIG. 22 of the switch assembly of FIG. 22 ; FIG. 24 is a top view of another switch assembly from FIG. 2 , shown removed from the remainder of the track, which serves to direct trolleys to the proper intersecting track sections during movement of the suspended panels in a wall forming direction; FIG. 25 is a rear view, taken along line 25 — 25 in FIG. 24 of the switch assembly of FIG. 24 . Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the invention, the drawings are not necessarily to scale and certain features may be exaggerated or omitted in order to better illustrate and explain the present invention. DESCRIPTION OF THE INVENTION For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. The invention includes any alterations and further modifications in the illustrated devices and described methods and further applications of the principles of the invention which would normally occur to one skilled in the art to which the invention relates. Referring now to FIGS. 1 and 2 , there is diagrammatically shown a top view and a perspective view of a movable wall panel system including an automatic track switching system of the present invention. The movable wall panel system serves to selectively compartmentalize a single, large room 20 into smaller rooms or areas. The operable wall includes a multitude of panels that extend from the floor to the ceiling of room 20 , which panels are shown in FIG. 1 in dashed lines at 22 in a stacked or storage position within a housing abstractly indicated at 24 . In FIG. 2 , one of the panels 22 is shown being moved to a wall-forming location. Although shown as being within room 20 , housing 24 typically is located directly adjacent to and outward of a side wall of room 20 as a specially designed pocket room. Wall panels 22 may be of any conventional construction. None of the panels 22 are hinged to adjacent panels in the inventive panel system, as the track switching system of the present invention uses panels that are each separately movable along the track between an operational, wall-forming position and a storage position. Panels 22 are movable along track segments mounted in the ceiling which form intersecting track sections 26 , 27 , 28 , 29 , 30 , 31 and 32 . Track sections 26 – 32 are designed such that when panels 22 are all in their wall-forming positions, room 20 is compartmentalized into six smaller rooms or areas 35 , 36 , 37 , 38 , 39 and 40 . This track configuration is merely illustrative and not intended to be limiting as the inventive track switching system may be employed with more complicated or less complicated tracks, including intersecting tracks that serve to compartmentalize a room into different numbers of smaller room or differently shaped rooms. In addition, the shown track configuration can be used in an even larger room than room 20 , which larger room is equipped with one or more additional operable wall panel systems that are similar to the shown system and which form walls in alignment with the walls formed by the shown wall panel system to provide suitable room compartmentalization. Referring now to FIG. 3 , portions of the operable wall of FIG. 1 are shown in a top view. Track sections 26 – 32 are of a conventional design suitable for use with the type of trolley employed with the panels. As described below, different types of trolleys may be used within the scope of the invention, and the track construction will be changed in a corresponding fashion to provide proper a suitable track and trolley combination. In the illustrated embodiment, track sections 26 – 32 are made of steel beams which are generally square in vertical cross-section. The wheels of the trolley ride along the bottom wall of the track section, and a slot centered in that bottom wall which extends longitudinally along the track section length permits passage of the pendant trolley bolt that attaches to the top of a panel 22 . Track sections 26 – 32 are mounted to the ceiling support structure by means of hanger brackets of conventional design, generally shown at 44 , positioned at spaced intervals along the lengths of the track sections. A switch assembly, generally designated 50 , serves as an intersecting track section for track sections 26 – 29 and is operably connected to each of track sections 26 – 29 . Switch assembly 50 is mounted to the ceiling support structure and, as described further below, is designed to cooperate with diverter element mounted on the panel trolleys to direct panels being moved along track section 26 in a wall-forming direction into one of track sections 27 , 28 and 29 . Another switch assembly, generally designated 60 , serves as the intersection of track sections 29 – 32 to which it is operably connected. Switch assembly 60 also is mounted to the ceiling support structure and is designed to cooperate with diverter elements mounted on the panel trolleys to direct panels being moved along track section 29 in a wall-forming direction into one of track sections 30 , 31 and 32 . The stacking of panels 22 within housing 24 is achieved through the use of switch assemblies 70 and 80 that are interconnected by track segment 72 and which are mounted to the ceiling support structure. Switch assembly 70 is operably connected to track section 26 , as well as to panel stacking track segments 73 and 74 mounted to the ceiling support structure by hanger brackets 44 . Switch assembly 80 is connected to panel stacking track segments 75 and 76 mounted to the ceiling support structure by hanger brackets 44 . Panels 22 are stacked along track segments 73 – 76 when stored within housing 24 . The length of track segments 73 – 76 is a function of the number of panels to be stacked, which in turn is a function of the length of the walls formed by the panels when moved to their wall-forming positions. In FIG. 3 , only six panels are shown to facilitate illustration, and these panels are designated as 22 a , 22 b , 22 c , 22 d , 22 e and 22 f . Each of these panels represent multiple panels of a similar type, with the types being distinguished herein based solely on the configuration of their trolleys. Specifically, and while the panels may otherwise be similar in most respects, as described below the trolleys of panel type 22 a differ from the trolleys of panel type 22 b–f , which in turn have trolleys that differ from each other. When the operable wall is fully extended, panels of the type 22 a are aligned along the entire length of track section 30 , panels of the type 22 b are aligned along the entire length of track section 31 , panels of the type 22 c are aligned along the entire length of track section 27 , panels of the type 22 d are aligned along the entire length of track section 28 , and panels of the type 22 e and 22 f are aligned along the entire length of track sections 26 , 29 and 32 . Naturally, the number of panels each of panels 22 a , 22 b , 22 c , 22 c , 22 e and 22 f represents can differ as it is dependent upon the length of the walls being formed, and it is not material to the present invention. Each of panels 22 is suspended from the track system by two trolleys, namely a lead trolley and a trailing trolley, positioned proximate opposite ends of that panel. As used herein, lead and trailing are referenced with respect to the trolley position during movement of the panels from a stacked position to a wall-forming position. The lead or front trolleys of panels 22 a , 22 b , 22 c , 22 d , 22 e and 22 f , when such panels are stacked, are disposed along track segments 73 and 74 , and the trailing or back trolleys of the panels when stacked are disposed along track segment 75 and 76 . For example, and with reference to stacked panel 22 e , a lead trolley generally represented at 82 suspends the panel from track section 73 , and a trailing trolley generally represented at 83 suspends the panel from track section 75 . The automatic track switching system of the present invention employs switch or diverter elements mounted to the trolleys of panel 22 . The overall form of the trolleys to which such diverter elements are attached may be selected from one of the many known designs. As a result, the term trolley is used generally herein, and is intended to encompass devices, including wheeled carriage and carriers, of all types that are operably connected to and movable along various tracks. The trolleys used with panel types 22 a through 22 f differ only in the configuration of their diverter elements. Each lead and trailing trolley includes a side diverter element. The diverter blades on the side diverter elements are located at one of three different lateral positions relative to and on each side of the trolley center line. In addition to the side diverter elements, each trailing trolley and only the trailing trolleys also includes a center diverter element. Center diverter elements are not used on the lead trolleys. In the description that follows only the trolleys for use with panel types 22 a , 22 c , and 22 e will be described. Trolleys with these panels will include side diverter elements positioned to the right of the trolley centerline from the perspective of a person in FIG. 3 standing at switch 50 and looking to the left toward housing 24 . Each trolley described will have a counterpart for use with panel types 22 b , 22 d or 22 f wherein the only difference is that the side diverter element is positioned to the left of the trolley centerline. One suitable lead trolley design for use with panel type 22 e is shown in FIGS. 4 and 5 and is generally represented at 100 . Trolley 100 includes a U-shaped carrier channel 102 having a base or web portion 103 and a pair of opposite upstanding sidewall portions 104 . A pendent bolt fitting 116 downwardly extends from the lower surface from the base portion 103 . The fitting 116 is internally threaded to receive a pendant trolley bolt 118 which is secured to the top section of a movable wall panel abstractly shown at 101 . Sidewall portions 104 defines bores 108 through which axles 110 are received. Four trolley wheel assemblies 112 are rotatably mounted on the axles 110 extending through sidewall portions 104 and wheel spacers 114 . Wheel assemblies 112 rollingly engage the various tracks for moving wall panel 101 . Guide rollers 120 extend into the track slot and serve to reduce friction between the trolley 100 and the slot. Guide rollers 120 are rotatably mounted on pivot posts 122 which are attached to the channel base portion 103 by any suitable means several of which are known in the art. The trolley 100 is equipped with a side diverter element 124 that cooperates with guide plates mounted on the inside of the upper surface of the track switch sections to route the panel through the switch. The diverter element 124 is displaced laterally or perpendicular from the trolley centerline in the direction of the motion of the trolley along the track. The diverter element 124 includes a blade portion 125 that extends above the trolley wheels 112 and a body portion 126 that fixedly attached such as by welding to the carrier sidewall portion 104 between the wheel assemblies 112 . With reference to FIGS. 6 and 7 , there is shown is a trailing trolley 130 that could be paired with trolley 100 of FIGS. 4 and 5 for use on panel type 22 e . The trolley 130 includes a center diverter element 134 in the form of a pair of pins 132 projecting vertically upward from a base plate 136 that is fixedly attached to the upper portion of carrier side walls 104 . Rather than the pin shown, a diverter element in the form of a rigid plate or blade may be used on the center diverter 134 . The trailing trolley 130 also includes a side diverter element 138 having a diverter blade 139 at the same lateral displacement from the trolley centerline as diverter blade 125 on trolley 100 . Side diverter element 138 also includes a body portion 140 which is fixedly attached to carrier sidewall portion 104 . Diverter blade 139 of trolley 130 is shorter in length than diverter blade 125 of lead trolley 100 . Based on these differences in diverter blade length along with the presence of a center diverter 132 on trailing trolley 130 , the lead and trailing trolleys 100 and 130 respectively can be routed differently through a given switch section. FIGS. 8 and 9 show lead and trailing trolleys that can be used on panel type 22 c . Lead trolley 150 in FIG. 8 includes a U-shaped carrier channel 152 having a base or web portion 153 and upstanding sidewalls 154 . A side diverter element in the form of a diverter blade 158 extends vertically upward from carrier channels sidewall 154 . The diverter blade 158 may be fixedly attached to sidewall portion 154 , such as by welding. Alternatively, the diverter blade may be integrally formed with channel sidewall 154 . As with the previous trolleys, diverter blade 158 functions to engage complimentary guide plates provided on the track switch section. As a lead trolley, trolley 150 includes no center diverter. In FIG. 9 , trailing trolley 160 for panel type 22 c is shown. As a trailing trolley, trolley 160 includes a center diverter element 162 which includes a pair of diverter pins 163 extending vertically upward from a base plate 164 that is fixedly attached such as by welding to carrier channel sidewall portions 154 . A side diverter blade 166 extends vertically upward from carrier sidewall portion 154 as shown. As in the previously described lead and trailing trolley pair, side diverter blade 166 of trailing trolley 160 is shorter in height than diverter blade 158 of lead trolley 150 . With reference now to FIG. 10 , there is shown a lead trolley 170 for use with panel type 22 a . Trolley 170 includes a U-shaped carrier channel 172 having a base or web portion 173 and upstanding sidewall portions 174 . Trolley 170 includes a side diverter element 176 positioned inwardly from carrier sidewall portion 174 . Diverter element 176 includes a body portion 178 that is preferably fixedly attached such as by welding to the inside of sidewall 174 between axle pairs 110 . Diverter blade 177 extends vertically upward from the body portion 178 . A trailing trolley suitable for use with panel type 22 a is generally represented at 180 in FIG. 11 . Similar to lead trolley 170 , trailing trolley 180 includes a side diverter element 186 that includes a body portion 188 fixedly attached to the inside of sidewall 174 and having a vertically extending diverter blade 187 which is shorter in height that diverter blade 177 of the lead trolley 170 . As a trailing trolley, trolley 180 includes a center diverter element 190 that includes a pair of diverter pins 192 that extend vertically upward from a base plate 193 . Base plate 193 is fixedly attached at one side to body portion 188 of side diverter element 186 . The other side of base plate 193 is fixedly attached to the opposite carrier channel side wall 174 . Side diverter blades 177 and 187 of trolleys 170 and 180 respectively represent the most laterally inward of the side diverter blade positions. The switch assemblies particularly designed for use in conjunction with the panel suspending trolleys of FIGS. 4–11 are shown in greater detail in FIGS. 12–25 . With reference now to FIGS. 12 and 13 , the switch assembly 80 that during wall stacking cooperates with the trolley diverter elements to route the trailing trolleys to their proper track sections is shown in top view and front view, respectively. In the illustrated embodiment, switch assembly 80 is formed from a single top plate 240 and three bottom plate sections 242 , 243 and 244 . Top plate 240 is suspended from a support structure with conventional fasteners in order to mount switch assembly 80 in the ceiling of room 20 . Plate sections 242 – 244 are each connected to top plate 240 in a vertical spaced-apart relationship in a well-known manner with a plurality of bolt and nut type fasteners that extend through tubular steel spacers 246 sandwiched between the various switch plates. The portions of these plate-connecting fastener assemblies that lie above the upper surface of top plate 240 are not shown in FIG. 12 for purposes of illustration. Plate sections 243 and 244 are horizontally spaced apart to provide a track path 248 into which enter trolleys being routed into switch assembly 80 in a panel stacking direction. Plate sections 242 and 243 , and plate sections 244 and 242 , are horizontally spaced apart to provide arcuate track paths or slots 249 and 250 , respectively. Track paths 248 , 249 and 250 , which provide the spaces through which extend the pendant bolts of the trolleys when the trolleys move or roll along the upper surface of plate sections 242 – 244 , are aligned with the track paths of track sections 72 , 76 and 75 , respectively. Diverters or guides used to selectively route trolleys passing along track path 248 into either track path 249 or 250 include a series of elongate plates mounted on either side of track path 248 . As shown in FIG. 12 , three elongate and arcuate guide plates 255 , 256 and 257 are fixedly attached, such as by welding to: the underside of the top plate 240 proximate and left of track path 248 . Guide plates 255 – 257 are evenly horizontally spaced to provide channels 259 and 260 . Three elongate, arcuate guide plates 262 , 263 and 264 are similarly attached to the underside of top plate section 240 right of track path 248 to provide channels 266 and 267 . The ends of the guide plates are pointed to aid in routing diverter blades into the appropriate channel or space as described further below. Referring to FIG. 13 , in conjunction with the height of the diverter blades of the side diverters of the trolleys, each of guide plates 255 – 257 and 262 – 264 are made sufficiently tall so as to project down from the top plate to a height at least slightly below the tops of the upstanding blades of the side diverter elements of the trailing trolleys. As so configured, the diverter blades must either enter one of the channels 259 , 260 , 266 and 267 , or enter the spaces laterally outward of guide plates 255 and 264 , when the trolleys pass along track path 248 . Specifically, when the trailing trolleys shown in FIGS. 6 , 9 , and 11 are separately routed through track path 248 in a wall-stacking direction, diverter blade 139 passes along the outer side of guide plate 264 , diverter blade 166 moves within channel 267 , and diverter blade 187 moves within channel 266 , thereby routing these trolleys into track path 250 . Although guide plates 255 – 257 and 262 – 264 are shown as having the same height, guide plates 255 – 257 and 262 – 264 could all be of different heights, so long as each plate is sufficiently tall so as to engage the appropriate trolley diverter blades during use. With reference now to FIGS. 14 and 15 , the switch assembly 70 that during wall stacking cooperates with the trolley diverter elements to route the lead and trailing trolleys to their proper track sections is shown in top view and front view, respectively. In the illustrated embodiment, switch assembly 70 is formed from a single top plate 270 , mounted in the room ceiling, and four bottom plate sections 272 , 273 , 274 and 275 . Bottom plate sections 272 – 275 are each connected to top plate 270 in a vertical spaced-apart relationship via spacing fasteners indicated at 280 . Bottom plate sections 274 and 275 are horizontally spaced apart to provide a track path 282 into which enter trolleys being routed in a panel stacking direction. Plate sections 273 and 275 , and plate sections 272 and 274 , are horizontally spaced apart to provide arcuate track paths 283 and 284 , respectively, in communication with track path 282 . Plate sections 272 and 273 are horizontally spaced apart to provide a linear track path 285 in communication and aligned with track path 282 . Track paths 282 , 283 , 284 and 285 are aligned with the track paths of track sections 26 , 73 , 74 and 72 , respectively. In order to maintain the downstream ends of track paths 283 and 284 in alignment with each other while at the same time, having the upstream ends of these track paths be staggered along the track path 282 to avoid relatively large gaps between the bottom plates, arcuate paths 283 and 284 are formed with different radiuses. One suitable radius for the tighter turn for the trolley is about eight inches, while a suitable radius for the more gentle turn can be about twelve inches. Other radiuses of curvature for either turn of the illustrated switch assembly, such as 16, or 20, or 24 inches and preferably greater than eight inches, may be employed. Different trolleys may allow use of still different radiuses of curvature, including larger and smaller radii. Guides used to selectively route lead trolleys passing along track path 282 into either track path 283 or 284 include a series of plates mounted to the underside of top plate 270 on either side of track path 282 . Arcuate guide plates 290 , 291 , and straight guide plate 292 are fixedly attached to the underside of top plate section 270 left of track path 282 to form channels 294 and 295 . Two arcuate guide plates 298 and 299 and straight guide plate 297 are similarly attached to the underside of top plate 270 right of track path 282 to provide channels 301 and 302 . Each of guide plates 290 – 291 and 298 – 299 is shorter than guide plates 255 – 257 and 262 – 264 of switch assembly 80 . Specifically, guide plates 290 – 291 and 298 – 299 are made sufficiently tall so as to project down to a height slightly below the tops of the upstanding blades of the side diverter elements of the lead trolleys, but not so tall as to extend below the tops of the shorter blades of the side diverter elements of the trailing trolleys. As a result, during operable wall stacking when the trolleys are passed through track path 282 , while the diverter pins of the trailing trolleys do not engage guide plates 290 – 291 and 298 – 299 so that these guide plates do not interfere with the motion of the trailing trolleys, the diverter blades of the lead trolleys are guided by these plates. Diverter blade 125 passes along the outer side of guide plate 299 , diverter blade 158 moves within channel 302 , and diverter blade 177 moves within channel 301 , thereby routing the trolleys of FIGS. 4 , 8 , and 10 into track path 283 . In order to ensure the trailing trolleys, being moved in a stacking direction through track path 282 continue into track path 285 and not track paths 283 and 284 , straight guide plates 292 and 297 define a channel 305 into which the center diverter of each of the trailing trolleys of FIGS. 6 , 9 , and 11 upwardly extends. Lead trolleys 100 , 150 , and 170 are depicted entering switch assembly 70 in FIGS. 16 , 18 , and 20 respectively. The side diverter blades of these trolleys operatively engage guide plates 297 – 299 . Trailing trolleys 130 , 160 , and 180 are depicted entering switch assembly 70 in FIGS. 17 , 19 , and 21 respectively. With these trolleys, only the center diverter operatively engages guide plates 292 and 297 . With reference now to FIGS. 22 and 23 , the switch assembly 50 that during wall extension cooperates with the upstanding blades of the side diverter elements of the trolleys to route the trolleys to their proper track sections is shown in top view and rear view, respectively. Switch assembly 50 is formed from a single top plate 310 , mounted in the room ceiling, and four bottom plate sections 312 , 313 , 314 and 315 . Bottom plate sections 312 – 315 are each connected to top plate 310 in a vertical spaced-apart relationship by spacing fasteners indicated generally at 318 . Bottom plate sections 312 and 313 are horizontally spaced apart to provide a track path 320 into which enter trolleys being moved into switch assembly 50 along track section 26 in a forward or wall extending direction. Plate sections 312 and 314 , and plate sections 313 and 315 , are horizontally spaced apart to provide track paths 321 and 322 , respectively, that are in communication with track path 320 and that have different radiuses of curvature similar to the track paths of switch 70 . Plate sections 314 and 315 are horizontally spaced apart to provide a linear track path 323 in communication and aligned with track path 320 . Track paths 321 , 322 and 323 feed the trolleys moving therealong into the track paths of track sections 27 , 28 and 29 , respectively. Guides used to selectively route trolleys passing along track path 320 into one of track path 321 , 322 or 323 include an arrangement of guide plates fixedly mounted to the underside of top plate 310 . In order to ensure engagement with the upstanding diverter blades of both. the lead trolleys and the trailing trolleys, each guide plate on switch assembly 50 is sufficiently tall so as to project down from the top plate to which it is attached to a height slightly below the tops of the shorter upstanding blades of the side diverter elements of the trailing trolleys. Plates of this standard height also naturally project below the tops of taller, upstanding blades of the side diverter elements of the lead trolleys. Guide plate 325 serves to route trolleys moving along track path 320 into track path 321 in the process of forming a wall along track segment 27 . Arcuate guide plate 325 is structured such that diverter blade 125 of trolley 100 , and diverter blade 139 of trolley 130 slide along the laterally outer face of guide plate 325 to route trolleys 100 and 130 into track path 321 . Straight guide plates 326 and 327 define a channel 328 through which slide diverter. blade 158 of trolley 150 and diverter blade 166 of trolley 160 . Guide plates 326 and 327 are structured to prevent trolleys 150 and 160 from entering track path 321 as the trolleys move forward in a wall extending direction along track path 320 . Guide plate 330 , which is aligned with guide plate 327 , functions to prevent trolleys 150 and 160 from straying into track path 322 , and thereby direct such trolleys into track path 323 by the engagement of diverter blades 158 and 166 against the laterally outward face of guide plate 330 . Straight guide plate 332 and, guide plate 327 together define a channel 333 through which slide diverter blade 177 of trolley 170 and diverter blade 187 of trolley 180 . Guide plates 327 and 332 prevent trolleys 170 and 180 from entering track path 321 as the trolleys move forward in a wall extending direction along track path 320 . Guide plate 335 is aligned with guide plate 332 and functions to prevent trolleys 170 and 180 from straying into track path 322 , and thereby direct such trolleys into track path 323 , by the engagement of diverter blades 177 and 187 against the laterally outward face of guide plate 335 . In a similar fashion, guide plates 340 , 342 , 344 , and 347 restrict access to track path 322 and track section 28 . With reference now to FIGS. 24 and 25 , the switch assembly 60 that during wall extension cooperates with the upstanding blades of the side diverter elements of the trolleys to route the trolleys to their proper track sections 30 – 32 is shown in top view and rearview, respectively. Except for its guide plate design, switch assembly 60 is constructed and mounted in a similar fashion to switch assembly 50 and includes top plate 370 , bottom plate sections 372 , 373 , 374 and 375 , and spacing fasteners 378 . Bottom plate sections 374 and 375 are spaced to provide track path 380 . Plate sections 372 and 374 , and plate sections 373 and 375 , are horizontally spaced apart to provide track paths 381 and 382 , respectively, with radiuses of curvature similar to the track paths of switch 50 . Plate sections 372 and 373 are spaced to provide a linear track path 383 in line with track path 380 . Track paths 380 , 381 , 382 and 383 are aligned with the track paths of track sections 29 , 30 , 31 and 32 , respectively. Guides used to selectively route trolleys passing along track path 380 into one of track path 381 , 382 or 383 include guide plates fixedly mounted to the underside of top plate 370 . The guide plates, although shown in FIG. 25 as having uniform heights, may be of different heights as long as each is sufficiently tall to engage the upstanding diverter blades of both the passing lead trolleys and the trailing trolleys. Arcuate guide plate 390 is structured such that diverter blade 158 of trolley 150 , and diverter blade 166 of trolley 160 , slide along the laterally outer face of guide plate 390 to route trolleys 150 and 160 moving along track path 380 into track path 381 in the process of forming a wall along track segment 30 . Straight guide plates 392 and 394 , together with a segment of guide plate 390 , define a channel 396 through which slides diverter blade 177 of trolley 170 and diverter blade 187 of trolley 180 . Guide plates 392 and 394 prevent trolleys 170 and 180 from entering track path 381 as the trolleys move forward in a wall extending direction along track path 380 . Guide plate 398 is aligned with guide plate 392 and functions to prevent trolleys 170 and 180 from straying into track path 382 , and thereby directs such trolleys into track path 383 , by the engagement of diverter blades 192 and 186 against the laterally outward face of guide plate 398 . In a similar fashion, guide plates 400 , 402 , and 404 restrict access to track path 382 and track section 31 . The automatic track switching system of the present invention will be further understood in view of the following description of its operation. When the panels are in the stacked arrangement shown in FIG. 2 , to compartmentalize room 20 the panels are first removed from housing 24 manually by a user who subsequently pushes or pulls the panel along the various track sections to a wall-forming position. In particular, when a panel of the type 22 a is moved from its stacked arrangement, the engagement of its trolleys with the switch assemblies 70 and 80 causes panel 22 a to be routed into track section 26 . Upon reaching switch assembly 50 , the above-described engagement of the guide plates mounted on the switch assembly with the upstanding blades of the side diverter elements of its trolleys cause panel 22 a to pass through switch assembly 50 into track segment 29 . When panel 22 a reaches switch assembly 60 , the engagement of the guide plates of the switch assembly with the upstanding blades of the side diverter elements of the trolleys automatically switches panel 22 a into the track path which leads to track section 30 . Panels of the type 22 c are routed via switch assemblies 70 and 80 into track section 26 , and are automatically routed by switch assembly 50 into track section 27 . Panels of the type 22 e are routed by switch assemblies 70 and 80 into track section 26 , and, depending on the order in which they are moved from housing 24 , such panels are aligned along track, segments 32 , 29 and 26 . The process of moving the panels back to a stacked arrangement is performed in generally the reverse order of the wall-forming process. As the panels traveling along track section 26 are moved rearward, the trailing trolleys enter the switch assembly 70 . Because the shorter upstanding pins of the side diverter elements of the trailing trolleys do not vertically extend upward to engage the guide plates of assembly 70 , the trailing trolleys are not affected by such guide plates. However, the center diverter disposed at the top of each trailing trolley engages the innermost guides 292 and 297 , thereby routing the trailing trolleys into track segment 72 and then ultimately to switch assembly 80 . As the panels continue to move rearward, the guide plates of switch assembly 80 engage the upstanding pins of the side diverter elements of the trailing trolleys to route the trailing trolleys into the proper track section for stacking, and the guide plates of switch assembly 70 engage the upstanding pins of the side diverter elements of the lead trolleys to route the lead trolleys into the proper track section for stacking. By utilizing diverter elements on the trolleys which are provided at different lateral spacings relative to the trolleys; it is possible to provide automatic track switching systems adaptable for use with a great variety of types of wall arrangements. Although trolleys with side diverter elements with three lateral pin positionings are shown, systems with fewer or possibly even greater lateral positionings are within the scope of the present invention. While this invention has been shown and described as having multiple designs, the present invention may be further modified within the spirit an scope of this disclosure. For instance, although the lead and trailing trolley pairs have been described as having side diverter elements at the same lateral positioning, the invention contemplates combinations of lead and trailing trolley pairs wherein the side diverters are positioned at different lateral displacements from the trolley centerlines. While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. It should be understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.	A multi-program trolley and track switch system is provided for a movable wall system having multiple panels supported and movable along multiple paths defined by multiple track sections. Switch assemblies automatically direct each wall panel to a predetermined wall forming location based on the arrangement of guide plates in the each switch assembly and the configuration of a diverter element associated with each trolley. Each switch assembly includes an array of vertically oriented guide plates offset at different lateral distances from the track path. Each trolley includes a side diverter element that is positioned a predetermined lateral distance from the trolley centerline to engage a pre-selected switch guide plate. In one embodiment, lead trolleys have only a side diverter element while trailing trolleys have both a side diverter element and a center diverter element.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATIONS [0001] No cross-reference is made to other applications. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OF DEVELOPMENT [0002] No Federal Government support was received in the development of this Invention. SEQUENCE LISTING, TABLE, OR COMPUTER PROGRAM LISTING [0003] No sequence listing, table, or computer program is attached or accompanies this Application. FIELD OF THE INVENTION [0004] This Invention relates to wall, floor and ceiling tiles, made of ceramic, plastic or other relevant materials that are adhered to a surface and are subsequently grouted. Features are provided that allow the tiles to self-align and self-space in relation to each other during installation, without the need for separate spacers. This Invention also has applications with cementitious and plastic composite driveway/walkway/deck pavers, and also with interior and exterior bricks, where the self-alignment features would be useful to position them during installation. BACKGROUND OF THE INVENTION [0005] Planar tiles are adhered to a wall, floor or ceiling using an adhesive. Separate spacers are generally placed between the tiles during installation, to provide alignment and spacing. The spaces between the tiles are subsequently sealed with a water-resistant grout to prevent water from penetrating beyond the tiles into the supporting wall and structure. Tiles are typically arranged in uniform patterns. [0006] Ceramic has been the material of choice for millennia of tile fabrication owing to its low material cost, water resistance and acceptance of colorful, hard surface finishes. Disadvantages of ceramic tiles include the inefficiencies arising from their weight, brittleness and their thru-hardness. Heavy ceramic tiles are costly to transport. They require specialized equipment to cut, and in the process are prone to break and create hazardous, airborne silica dust. In contrast, the fabrication of plastic tiles by injection molding allows for tiles that are relatively light, are easily cut with conventional wood cutting tools, have high impact strength, and can be formulated to provide flame retardant and anti-microbial properties that are inherent to ceramic tiles. The recent development of clear, high-gloss, hard coatings for plastics and of digital printing on plastic surfaces now permits durable and colorful plastic tiles to be produced. All the known attributes of injection molded plastic parts, including shape, texture, raised and relieved features, molded-in color and clarity, are easily incorporated into a plastic tile. Where necessary, plastic tiles can be deformed to contour around a curved surface, something not possible with rigid ceramic tiles. [0007] This Invention discloses a means that allows the tiles to self-align and self-space during their installation, and includes integral aligning and spacing features on the tiles that replace the need for separate spacers typically required when installing conventional ceramic tiles. This Invention can be incorporated into both ceramic and plastic tiles, although the plastic injection molding process ensures that these features are accurately produced. Similarly, this Invention can be incorporated into driveway/walkway/deck pavers to facilitate alignment in straight-laid or running bond patterns. [0008] The prior art includes a considerable number of interlocking floor and wall tiling systems as well as interlocking, engineered wood strip-flooring. All of these inventions focused on a desire to have the tiles or strip-flooring connect with each other while they were being aligned with each other. Interlocking flooring and decking systems typically “float” on the sub-floor, which allows for thermal expansion and contraction of the materials throughout the seasons, while ensuring they remain tightly connected. The prior art plastic floor and wall tiling systems included “male” features on two sides to mate with “female” features on the remaining two sides. The female features were typically located on the underside of the tile to cover the projecting male features. The strip-flooring systems had a male (or tongue) feature that engaged with a female (or groove) feature on the opposite side. In all cases, these interlocking features ensured that the tiles were kept tightly fitted. However, a consistent problem existed with all of these prior art systems in that the interlocking features prevented the tiles from being continuously installed in all four directions from a fixed tile. A layout that calls for a particular pattern to be in the center of the floor or wall requires that the remaining tiles be aligned outward in all directions from this central feature. The tiles on the back wall of a bathtub surround are typically installed from a centerline outward to ensure both end-cuttings match. At best, the interlocking features provide for three directions, but more typically only two. The only exception is a dovetail interlock with symmetric features on all sides. However, owing to the narrow grout joint typically required between adhered wall and floor tiles, this concept cannot be rendered into a practical design. For these reasons, grouted wall and floor tiles have not included interlocking features and still require secondary spacers during installation to provide spacing and alignment. Furthermore, interlocking features force the tiles into a rigidly aligned pattern, which does not allow for variations that might be present in the wall or floor surface. Therefore, for wall and floor tiles that are adhered to a surface and subsequently grouted, it is undesirable to have the tiles connect or interlock. [0009] Brown (U.S. Pat. No. 2,490,577 and U.S. Pat. No. 2,490,577) disclosed a system of tongue and groove (or pin and eye) connectors for plastic tiles. These plastic tiles were widely installed in the 1950s and 60s, but had inherent problems. It was assumed that having the tiles tightly fitted, without a grouted gap, was sufficiently waterproof to avoid water infiltration to the supporting wall. This proved otherwise, as mildew quickly built up behind and between the tiles. Unidirectional assembly for the tongue and groove design meant that traditional symmetries of tiling could not be achieved. This lead to tiling jobs that looked unbalanced. In addition, repair of damaged tiles was not possible without damaging adjacent tiles in the pin and eye method of attachment owing to a failure to foresee that a closed-loop captured flush to the wall cannot be removed from a pin mate. Masanek (U.S. Pat. App. No. 2013/0086861) is essentially the same patent as Brown's U.S. Pat. No. 2,490,577. [0010] In the meantime, considerable development and commercialization of interlocking floor tiling and strip-flooring systems has occurred. In all cases, the desired result of the interlocking connection was to have the tiles secured tightly together. Shirakawa (U.S. Pat. No. 5,972,655) disclosed a two-stage connection of which the first stage includes features that appear to allow the deckings to be assembled in four directions, but would not be possible to complete the second stage. His invention disclosed a hook feature on the side of a first decking that inserted into a receptacle on the underside of a second decking, by first passing through an opening in its lower side wall. He disclosed that the inclined upper surface of the hook facilitated insertion of the hook into the receptacle by having it remain in contact with a series of mating curved ribs on the inside wall above the opening in the second decking so as to guide it into the receptacle. Once fully assembled, the mating ribs increased the contact area with the inclined upper surface, which facilitated a tight engagement, and thus a tight and reliable connection between the two deckings. His full disclosure, including the secondary fixture to secure the deckings together, is consistent with having the second decking lifted slightly to allow the tip of the hook on the first decking to pass through the opening and then having the second decking pressed down lightly to allow the ribs to guide the hook into the receptacle, similar to the way most other interlocking tiling systems are assembled. Assuming for the moment that each decking is secured down after installation (as is the case with tiles adhered to a surface), by having the hook features of one decking pass under the mating decking, it is only possible to continuously assemble the deckings in three directions. There will always be the case in one direction, where the hooks on the two sides of the next decking cannot simultaneously get through the openings of the two adjacent secured deckings. Sjoberg (US-2003/0094230) disclosed an interconnecting means for strip-flooring, which ensured that the flooring was tightly interlocked. He discloses a continuous projecting feature on one edge, which can be rotated into a mating groove on the adjacent flooring. As with Shirakawa's invention, the projecting interconnecting feature on one flooring is covered by adjacent flooring, which would then not be a suitable means for allowing tiling to be assembled in 4 directions. [0011] Tillery et al (US 2013/0291457) disclosed a modular industrial floor tile system with dovetail interlocking connection means. His invention is principally focused on the composition of the floor tile, such that it can be produced with a uniformly thick substrate and an overmolded rubber surface of varying depth. The thickness of the tile is reduced near the perimeter to prevent the upper edges from being damaged, a concern with industrial floor matting. Although the particular design of his dovetail connecting means was well known prior to the disclosure of his flooring system, it is instructive to look at the limitations of his dovetail connection in detail, as well as the inability to adapt it to a practical design for the particular application of tiles that are to be bonded to a surface. To achieve adequate retention from the dovetails, the interlocking surfaces should be in line as much as possible. These in-line surfaces can be drafted, and by rounding the lower edges, the initial alignment can be improved. But, in all cases, it is necessary to mate the dovetails in a planar orientation. They certainly cannot be rotated into position, as would be expected when installing wall tiles. Even to provide substantial inward curvature to the in-line surfaces, in an attempt to allow the dovetails to rotate, would effectively eliminate almost all of the engagement surfaces of the dovetails. What features still remained, particularly when providing for only a 1/16″ gap between the tiles, would be very difficult to accurately produce and would be so weak as to break off with virtually no effort. [0012] Bathelier et al (US 2008/0199676) disclosed a tongue and groove mating means to assemble strip flooring, commonly known as “click” flooring due to the sound produced when being assembled. His “floating” floor system is intended to provide a tight fit between each plank. Owing to the groove being inboard of the edge of the plank, the inherent overlap only allows the tongue of the next plank to be installed in the groove of the last plank in one direction. It would be impossible to assemble them in the opposite direction without first lifting the last plank, something that could certainly not be done with tiles that are to be bonded to a surface. Thus, Bathelier's design and other designs similar to it, severely limit the directions of installation. Bathelier disclosed that the tongue has a lower curved surface on which a plank can be initially rotated against the lower surface of the previous plank before being inserted into the recessed groove. However, this surface has no use to provide either lateral alignment or spacing in his flooring system, as there is no contact with it when assembled. In his invention, the lateral alignment is achieved through contact between vertical surfaces above the tongue and groove and between inclined planes to the rear of the tongue. SUMMARY OF THE INVENTION [0013] This Invention overcomes the limitation of all the prior art, where the end result is to have aligned and equally spaced tiles that are bonded to a surface and subsequently grouted. Integral alignment and spacing features are provided, which eliminate the need for secondary spacers while enabling the tiles to be bonded to a surface in all four directions. Thus, the disclosed tiles can be laid symmetrically from a centerline as is typically required on the back wall of a bathtub surround. Further, these tiles can be aligned in either a straight-laid or running bond pattern. Border and corner tiles with similar alignment features are disclosed. Where reference is made to wall tiles being installed vertically in every direction, floor and ceiling tiles can be installed horizontally in every direction (left, right, forward, backward). [0014] As mistakes in a pattern layout and damage to the tiles can occur during an installation, removal of individual tiles can be achieved without damaging adjacent tiles. [0015] While reference is made throughout this Invention to tiles that are generally rectangular in shape, the self-aligning system can be incorporated into many different tile shapes. [0016] This Invention also has use for cementitious and plastic composite driveway/walkway/deck pavers, whereby the self-aligning and self-spacing features will aid in positioning the pavers in a straight-laid or running bond pattern on the ground. Furthermore, the Invention has use with exterior bricks, whereby the self-aligning and self-spacing features will aid in positioning the bricks exactly in a running bond or brick pattern while the mortar is being squeezed out. BRIEF DESCRIPTION OF THE DRAWINGS [0017] In the drawings, which illustrate embodiments of the invention: [0018] FIG. 1 is a front, side and rear view of a square tile, with detail views of the self-aligning and self-spacing feature [0019] FIG. 2 is a front and side view of a border and a corner tile [0020] FIG. 3 is a front view of a straight-laid installation of multiple square tiles, border tiles and a corner tile, with a detail view of the self-alignment features of two adjacent tiles. [0021] FIG. 4 is a front view of a running bond installation of multiple square tiles and a border tile, with detail views of the alignment features of three adjacent tiles. [0022] FIG. 5 is an isometric view of four squares tiles being laid in a straight-laid pattern, showing the 4 th tile being initially aligned with the 3 rd tile. A section view, along with a detail view, shows details of the contacting surfaces during the initial alignment. [0023] FIG. 6 is an isometric view of four squares tiles being laid in a straight-laid pattern, showing the 4 th tile almost in its final position. A section view longitudinally through three sets of self-alignment features, further elaborated in three detail views, shows three stages of the self-alignment features laterally aligning with each other. A second section view, further elaborated by a detail view, shows how the projected profile of the self-alignment feature aids with the alignment and spacing of the tiles. DETAILED DESCRIPTION OF THE INVENTION [0024] A self-aligning and self-spacing square tile in the preferred embodiment of this Invention is shown in front view in FIG. 1( a ) . The tile can be produced using a variety of materials and processes. Furthermore, the tile can be rectangular or other multi-sided or rounded shapes. Cosmetic face 1 , which can include shapes, textures, graphics and coatings, provides the aesthetic appearance of the tile. The four side walls 2 each support three integral self-alignment features, for which the top surface 6 for each is indicated. The quantity, relative position and shape of these self-alignment features are critical to their functionality and form the basis of this Invention. For the square tiles, two self-alignment features are grouped near one end of each side wall 2 and a single self-alignment feature is positioned near the other end, the relevance of which will be more evident in subsequent views. [0025] In FIG. 1( b ) , the side view of the square tile shows the self-alignment features originating from the bottom edge of side wall 2 . All grouted tiles should be of sufficient thickness to ensure that the grout between them has adequate depth to create a water-resistant seal. This raises an important consideration about whether it is detrimental to the grout to have the self-alignment features left between the tiles. Most tile installers will argue that the commonly used separate spacers should be removed prior to grouting. This is partly because the separate spacers can, in some cases, be almost the height of the tiles, leaving little depth for the grout. But, more importantly, they are generally molded in a plastic material that cannot be bonded using tile adhesives (and grouts), thus ensuring that they can be easily removed prior to grouting. By leaving them between the tiles, they can become dislodged over time and create weaknesses in the grout. Integral self-alignment features, on the other hand, cannot become dislodged from the tiles and are made of the same material as the tile to which the grout will adhere. Furthermore, the relative height of the self-alignment features to the height of the tile itself is such that a sufficient grout depth can be ensured. [0026] In FIG. 1 ( c ) , the rear view of the square tile shows the underside 4 of the cosmetic face 1 . Ceramic tiles are typically quite thick to ensure they have sufficient strength for their relatively brittle composition. Shallow ribs are typically included on the underside of a ceramic tile to limit the thickness of the tile adhesive when the tile is pressed into position. A solid tile of uniform thickness reduces the likelihood of the solvents in the tile adhesive being trapped under the tile, which can inhibit the curing of some adhesives. A plastic tile also needs to be relatively thick to provide sufficient depth for the grout. However, thick sections in plastic molded parts are undesirable, as they increase material and processing costs and potentially contribute to cosmetic defects and warp. Thus, for a plastic tile, it is desirable to have a wall thickness under the cosmetic face 1 that is considerably less than the height of side wall 2 , thus creating a hollow underside of the tile. Adhesives that readily bond to plastic, which chemically react or require a solvent (or water) to flash off prior to bonding, are suited to bonding the hollow plastic tiles. The side wall underside 3 provides a bonding surface around the entire perimeter of the tile. Ribs 5 , extending from underside 4 flush to the bottom of the tile, provide support for cosmetic face 1 and additional bonding surfaces. The particular “deck plate” pattern shown allows for optimum support of a cut edge of the tile should a partial tile be needed for an installation. Additionally, ribs 5 are discontinuous to reduce the likelihood of causing warp in the plastic tile, yet allow the installer to slightly bend the tile when installing it on curved surfaces, something not possible with rigid ceramic tiles. [0027] In FIG. 1( d ) , the side view of the self-alignment feature depicted in Detail A shows that it is a projection off side wall 2 , originating at the bottom of the tile. The top surface 6 is substantially below the cosmetic face 1 to allow for adequate grout coverage and it projects outward to top edge 7 which can be filleted. Front face 8 extends downward from top edge 7 to join inward front curvature 9 , which originates at the bottom of the side wall 2 . The two sides of the self-alignment feature each consist of side face 10 and, below it, inward side curvature 11 to form a relatively sharp edge where they meet front face 8 and inward front curvature 9 . Inward side curvature 11 extends down to the same level as the bottom of side wall 2 . These details are illustrated in Detail B in FIG. 1( e ) . Inward side curvature 11 is a sweeping curvature that ensures, when a tile is positioned or rotated into place along any axis, that the clearance with respect to the top edge, side face, and inward side curvature of the alignment features on an adjacent installed tile is limited and controlled. Inward front curvature 9 is adequately curved to allow a tile being installed to rotate against one installed tile and correct its spacing with another installed tile. The relevance of these details is more evident in the subsequent assembly views. The height of the inward front curvature 9 and that of the inward side curvature 11 does not necessarily have to be the same, as these curvatures serve different functions. Having front curvature 9 and side curvature 11 extend fully up to top face 6 , thereby eliminating front face 8 and side face 10 , is included in the preferred embodiment of this Invention. [0028] In FIG. 2( a ) , a self-aligning and self-spacing border tile, of typical rectangular profile, is shown in front view. Cosmetic face 12 is supported on one longitudinal edge by side wall 2 , and on the two lateral edges by end walls 15 . A cosmetic edge 14 transitions cosmetic face 12 into the bottom of the tile, as shown in FIG. 2( b ) . Three self-alignment features are provided on side wall 2 , as indicated by their top face 6 , and are similarly positioned to those on the four side walls 2 of the square tile depicted in FIG. 1 . On one end wall 15 , one self-alignment feature is provided. And on the other end wall 15 , two self-alignment features are provided. In FIG. 2( c ) , a self-aligning and self-spacing corner tile is shown in front view. Cosmetic face 13 is supported on two sides by end walls 15 , which are of similar length as the end walls 15 on the border tile. One or two self-alignment features are provided on end walls 15 , as indicated by their top face 6 . Cosmetic edge 14 transitions cosmetic face 13 on two sides to the bottom edge of the tile, as shown in FIG. 2( d ) . The underside of both the border tile and the corner tile are of similar design as that of the square tile in FIG. 1 . The geometry of the self-alignment features in FIG. 2 is identical to the geometry depicted in Details A and B of FIG. 1 . The relevance of the positioning of these self-alignment features will become more evident in the subsequent assembly views. [0029] In FIG. 3 , the front view of square tiles, border tiles and a corner tile installed in a straight-laid pattern is shown. The cosmetic faces of representative examples have been identified by their respective cosmetic faces, 1 a and 1 b, 12 , and 13 . The relevance of the positioning and width of the self-alignment features on the side walls and end walls of the tiles is now more evident. Two square tiles 1 a and 1 b are butted up against each other. In the detail view in FIG. 3( b ) , the single self-alignment feature, identified as its top face 6 b, near one end of the side wall 2 b on tile 1 b, fits closely between the dual self-alignment features, identified twice as 6 a, on the side wall 2 a of tile 1 a. For the second set of three self-alignment features between tiles 1 a and 1 b immediately above those in Detail C, the single self-alignment feature on tile 1 a fits closely between the dual self-alignment features on tile 1 b. Similarly, for the border tile 12 and the corner tile 13 , the single self-alignment feature on one end wall fits closely between the dual self-alignment features of the end wall of the adjacent tile. Thus, all the tiles are perfectly aligned with each other. Having additional sets of self-alignment features on each side wall or having more than single or dual self-alignment features is part of the preferred embodiment of this Invention. With the tiles butted up against each other, the specific distance that the self-alignment features project off the side walls then limits the spacing between the tiles and controls the grout gap. This is the self-spacing aspect of this Invention. Because plastic injection molded tiles can be molded very accurately, it is possible to size the tiles, along with their self-alignment features, such that they will be uniformly positioned in a standard dimension. Thus, 6-inch tiles could be positioned exactly every 6 inches. This makes it very easy for an installer to determine exactly how many full tiles are needed and what the width of any partial tiles will be. If the installer wants a slightly larger grout gap than is provided by the projected distance of the self-alignment features, separate spacers could be used to control the grout gap while the self-alignment features still provide lateral alignment of the tiles, as long as they remain in contact with one another. [0030] In FIG. 4 , the front view of square tiles and a border tile installed in a running bond (or brick) pattern is shown. Once again, the positioning and shape of the self-alignment features on the side walls of each tile play a critical role. In a running bond pattern, two sides of the tiles are aligned in the same way as those of the straight-laid pattern shown in FIG. 4 on the vertical sides of the tiles. On the horizontal sides in FIG. 4 , the tiles are offset by half their width to create a running bond pattern. To clarify how the self-alignment features work for the horizontal sides, three square tiles are identified by their cosmetic faces 1 a, 1 b, and 1 c in FIG. 4( a ) . In the detail view in FIG. 4( b ) , four self-alignment features appear nested together between tiles 1 a and 1 c. The dual self-alignment features, indicated twice as 6 a, and the dual self-alignment features indicated twice as 6 c, are integral to tiles 1 a and 1 c, respectively. The dual self-alignment features 6 c are positioned to the left of the dual self-alignment features 6 a. In FIG. 4( c ) , single self-alignment features 6 b and 6 c are integral to tiles 1 b and 1 c, respectively. The two self-alignment features appear next to each other between tiles 1 b and 1 c in the running bond pattern, with the single self-alignment feature 6 c to the right of the single self-alignment feature 6 b. Although it is possible to offset the dual self-alignment features 6 c to the right of dual alignment features 6 a, an obvious gap would appear between the single self-alignment features 6 b and 6 c. The effect would be an “offset” running bond pattern, which may appeal to some installers. The self-alignment features on the longitudinal side of the border tile, identified by its cosmetic face 12 , are positioned in the same way as they appear on the square tiles to achieve the running bond pattern. [0031] In FIG. 5( a ) , four square tiles being laid in a straight-laid pattern are identified by their respective cosmetic faces 1 a through 1 d. With tile 1 a installed first, tile 1 b was then installed to its right and tile 1 c above it. The installation process described for tile 1 d is instructive as to how tiles 1 b and 1 c were installed with tile 1 a. As would have been the case when tiles 1 b and 1 c were being installed with tile 1 a, tile 1 d is initially tilted on an angle and pushed up against the self-alignment features on tile 1 c. Initially tilting tile 1 d, as it is being positioned, avoids having its underside prematurely come in contact with the adhesive on the wall. In FIG. 5( b ) , the section view is through the self-alignment features of tiles 1 c and 1 d, which are shown in detail in FIG. 5( c ) below it. Tile 1 d slides on radius 9 d as it is being pushed on an incline toward tile 1 c. It comes to a stop as top edge 7 c contacts side wall 2 d. The projected distance of 6 c, which controls the grout gap, also ensures that the tops of side walls 2 c and 2 d do not touch each other as tile 1 d is inclined at a reasonable angle. While tile 1 d is still being pushed against tile 1 c, it is rotated downward into its final position in full contact with the installation surface with adhesive. (Final alignment of tile 1 d with tile 1 b is described separately in FIG. 6 .) During this process, radius 9 d slides in an angular motion against the installation surface, while side wall 2 d pivots against top edge 7 c. Top edge 7 d rises up such that front face 8 d comes in contact with side wall 2 c when tile 1 d is fully down. At this point, the front face 8 c (not shown) would also be in contact with side wall 2 d. It is evident in FIG. 5( c ) that the height of top surface 6 c (and thus 6 d ) is limited by the highest point at which top edge 7 c remains in contact with the side wall 2 d. However, the height of top surface 6 c (and 6 d ) should be minimized to ensure that tile 1 d can be rotated into place in tight proximity to tile 1 c. [0032] The views within FIG. 6 focus on the final alignment of tile 1 d with tile 1 b from FIG. 5 , just before it contacts the installation surface. The right side of tile 1 d is still slightly raised. In FIG. 6( b ) , the section view is taken between tiles 1 a and 1 c and tiles 1 b and 1 d, such that the self-alignment features on each of the tiles are sectioned. In the detail view in FIG. 6( c ) , the dual self-alignment features on tile 1 a are identified twice by the top surfaces 6 a, and the single self-alignment feature on tile 1 c is identified as 6 c. The side faces 10 a and 10 c are closely fitted with each other to provide lateral alignment of the two tiles in their final position. In the two detail views in FIG. 6( d ) and FIG. 6( e ) , the dual and single self-alignment features on tiles 1 b and 1 d are identified by their respective top surfaces 6 b and 6 d. In FIG. 6( d ) , inward side curvature 11 d is shown guiding side face 10 d into position next to side face 10 b. In FIG. 6( e ) , the two inward side curvatures 11 d are shown just above the two side walls 10 b to highlight how inward side curvatures 11 d provide both guidance and clearance with side faces 10 b to ensure a close lateral fit of the self-alignment features. [0033] In FIG. 6( f ) , the section view is taken through tiles 1 b and 1 d at the self-alignment feature identified as 6 d in FIG. 6( e ) , in order to show how tile 1 d is angularly positioned with tiles 1 c and 1 b. The installer may not have fully pushed the top left corner of tile 1 d against tile 1 c, which would result in tile 1 d being angularly rotated over top of tile 1 b. In FIG. 6( g ) , the detail view shows how this is corrected. If front curvature 9 d had initially been overtop side wall 2 b, front curvature 9 d would have contacted the corner between cosmetic face 1 b and side wall 2 b. As tile 1 d is pushed down, front curvature 9 d guides front face 8 d up against side wall 2 b, thereby rotating tile 1 d into the correct position. While this is occurring, the self-alignment features on 1 d that are adjacent to those on tile 1 c are also being angularly positioned. Thus, when installed, tile 1 d is both laterally and angularly locked into position with the adjacent tiles 1 b and 1 c. The true extent of this Invention is now defined.	A tile system has been devised that includes novel, integral self-aligning and self-spacing features on the side walls of the tiles to provide uniform self-alignment continuously during installation in all directions, both on vertical and horizontal surfaces. Border and corner tiles with similar self-alignment features are shown. The self-alignment features will align the tiles in either a straight-laid or running bond (or brick) pattern. The self-alignment features define regular, parallel gaps between adjacent tiles, without the need for separate spacers, in which waterproof grout is applied. The self-alignment features have application with bonded and non-bonded tiles, driveway/walkway/deck pavers and mortared interior and exterior brick, which can be manufactured in a variety of materials and processes. This Invention pays particular attention to plastic injection molded tiles that are to be bonded to a surface and subsequently grouted.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION [0001] This invention relates in general to wellbore casing or liner and in particular to a high integrity hanger and seal used in casing while drilling operations. BACKGROUND OF THE INVENTION [0002] In conventional well drilling, several casings 12 , 14 are installed in the well borehole 10 to maintain the integrity of the borehole wall, as shown in FIG. 1 . The installed casing 12 , 14 further prevents undesired flow of drilling fluid into the formation or flow of fluid from the formation into the borehole 10 . An initial depth of the borehole 10 is drilled and a casing segment 12 is cemented in place. A subsequent casing 14 , which is to be installed in a lower segment of the borehole 10 , is lowered through the previously installed casing 12 of an upper borehole segment. [0003] The casing 14 to be installed in a lower segment may be hung at the wellhead 16 as shown in FIG. 1 . The casing 14 of the lower segment is of smaller diameter than the casing 12 of the upper segment to allow passage of the subsequently installed casing 14 through the casing 12 of the upper segment. Thus, the casings 12 , 14 are in a nested arrangement with casing diameters decreasing in downward direction Annuli are formed between the outer surfaces of the casings 12 , 14 and the borehole wall to seal the casings 12 , 14 from the borehole wall. Cement is introduced into the annuli to cement the casings in place. Due to this nested casing arrangement, a relatively large borehole diameter is required at the upper part of the wellbore. A large borehole diameter typically involves increased costs due to heavy casing handling equipment, large drill bits and increased volumes of drilling fluid and drill cuttings. Drilling rig time is involved due to required cement pumping, cement hardening, equipment changes due to large variations in hole diameters to be drilled, and the large volume of cuttings drilled and removed. [0004] To try and remedy the issues with the nested casing arrangement, expandable tubulars have been employed for the sections of casing, or liner, below the upper section of casing. The subsequent expandable tubular is lowered into a portion of the well drilled out below the upper casing. Once in place, the tubular is expanded radially such that the bore diameter is approximately slightly less that of the upper casing. An overlap exists between the upper and lower casing segments that creates a seal between the segments when the tubular is expanded. However, due to well pressure and thermal growth, the seal may lose integrity. [0005] A need exists for a technique that addresses one or more of the limitations of the existing procedures for forming new sections of casing in a wellbore. The following technique may solve these problems. SUMMARY OF THE INVENTION [0006] In an embodiment of the present technique, a casing may be comprised of a plurality of casing segments joined approximately end to end, with each casing segment comprising a wicker profile formed on the interior surface at one end of the casing segment. Once the casing segment is cemented in place within the well borehole, a subsequent casing segment having a smaller diameter than that of the cemented casing may be lowered on a drill string through the initial, cemented casing. The drill string may extend past the lower end of the subsequent, lower casing where a bottom hole assembly (“BHA”) is attached to the drill string. The BHA may comprise a drilling head and an underreamer. The drilling head and underreamer rotate during drilling operations to drill a desired length below the end of the initial casing segment. Once the drilling operation is complete, the BHA may be retrieved and the subsequent casing is cemented in place in a conventional manner such that a portion of the subsequent casing segment overlaps with the wicker profile of the initial, upper casing segment. [0007] In an illustrated embodiment, a pig or expandable cone may then be run into the bore of the lower, subsequent casing on a string to radially expand the lower casing along its length. As the lower casing segment is radially expanded by the pig, the portion of the lower casing segment that overlaps with the wicker profile of the upper casing is deformed onto the wicker profile to form a metal-to-metal seal. The wicker profile bites into the exterior surface of the subsequent casing segment In addition to forming a high integrity metal to metal seal, the wicker mechanism can function as a casing hanger while the cement cures. The procedure described above may be repeated until the desired length of casing is installed. [0008] The combination of the wicker profile, and the radial expansion of each subsequent casing segment to form a metal-to-metal seal against the wicker profile, improves sealing between casing segments while reducing the telescoping and borehole reduction effect. BRIEF DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 is a sectional view of a casing arrangement of the prior art. [0010] FIG. 2 is a sectional view of joined casing segments, in accordance with an embodiment of the invention. [0011] FIG. 3 is a sectional view of overlap or packoff region, in accordance with an embodiment of the invention. [0012] FIG. 4 is a sectional view of a casing while drilling operation, in accordance with an embodiment of the invention. [0013] FIG. 5 is a sectional view of a casing while drilling operation, in accordance with an embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION [0014] Referring to FIG. 2 , an embodiment of the invention shows a portion of a casing 20 is within a well borehole 24 . Cement 22 is introduced into an annulus formed by the borehole 24 and the casing 20 to hold the casing 20 in place. In this embodiment, the casing 20 may be comprised of a plurality of segments, for example, an upper or initial casing or liner segment 28 is joined at one end with a lower or subsequent liner or casing segment 26 . The term “liner” refers to casing that has its upper end a short distance above a previously installed string. A casing string normally extends to a wellhead at the surface. The terms “liner” and “casing” are used interchangeably herein. [0015] An overlap region, tubular seal section, or packoff 32 , shown in more detail in FIG. 3 , exists at approximately where the segments 28 , 26 are joined to each other after the lower casing segment 26 has been radially expanded. The upper casing segment 28 has an exterior surface 34 that is in contact with the cement 20 and also has an inner bore 30 . Likewise, the lower casing segment 26 has an exterior surface 38 that is in contact with the cement 20 and has an inner bore 36 . The inner bore 36 of the lower casing segment 26 has a diameter that is slightly smaller than the diameter of the inner bore 30 of the upper casing segment 28 . [0016] Referring to FIG. 3 , an embodiment of the invention shows an enlarged illustration of the overlap region 32 in a set position, with the lower casing segment 26 radially expanded. In the set position, the exterior surface 38 of the lower casing segment 26 is sealingly engaged with a wicker profile 40 formed onto an interior end of the upper casing segment 28 . Wickers 40 are not threads, but a series of small triangular-shaped, parallel grooves and ridges on the sealing surface. The wickers may have a depth ranging from 1/16″ to ⅛″. The wickers 40 are formed from metal and bite into the exterior surface 38 of the lower casing segment 26 to form a metal-to-metal seal to create a better seal than a smooth surface. Initially, the wicker profile 40 may also function as a hanger to support the weight of the lower casing 26 prior to the cement 20 curing around lower casing 26 . Further, the interior of the overlap region 32 may comprise a set of grooves 42 above and below the wicker profile 40 . The grooves 42 initially may allow a drill head to be located during casing while drilling operations. Once a drilling operation is completed, the grooves 42 may further function as pockets into which the lower casing segment 26 may extrude to thereby provide a secondary sealing function. Although a downward facing shoulder is shown, a shoulder is not necessary. [0017] During casing operations as shown in FIGS. 4 and 5 , the upper casing segment 28 may be lowered into the well borehole 24 and cased with cement 22 that is pumped through the bore of the upper casing 28 and back up the annulus in a conventional manner as taught by US 2007/0175665, hereinafter referenced in its entirety. If the upper casing segment 28 is the first segment then it may be hung from a hanger at the wellhead (not shown). As described in FIGS. 2 and 3 , the overlap or packoff region 32 is formed on the lower, interior end of the upper casing segment 28 . [0018] The wellbore will be drilled deeper, either with a drill pipe string or by liner drilling. Continuing to refer to FIG. 4 , the lower or subsequent casing segment 26 may be lowered into the well borehole 14 through the interior of the upper casing 28 . In this embodiment, the lower casing segment 26 is suspended from a drill string 50 via a sub 52 attached to the drill string for liner drilling. That is, the well is being drilled while casing 26 is being run into the well. The sub 52 may be ported to allow for the flow of drilling mud and other fluid during drilling operations. The drill string 50 may extend through the sub 52 and past the lower end of the lower casing 26 where a bottom hole assembly (“BHA”) 60 is attached to the drill string 50 . The BHA may comprise a drilling head 62 and a collapsible underreamer 64 that may radially extend beyond the exterior surface 38 of the lower casing segment 26 . The drilling head 62 along with the underreamer 64 rotate during drilling operations to drill a desired length below the end of the upper casing segment 28 . Once the desired drilled length is achieved, the underreamer 64 is collapsed and the BHA 60 may be retrieved. [0019] As shown in FIG. 5 , the lower casing segment 26 may be conventionally cemented, such as by reference to US 2007/0175665, and a pig or expandable cone 70 may then be run into the bore of the lower casing 26 on a string 72 . The outer diameter of the pig 70 is expandable to be slightly larger than the bore of the lower casing segment 26 to allow the pig 70 to exert a force Fo ( FIG. 3 ) to radially expand the lower segment 26 or at least an overlapping portion of lower segment 26 . Pig 70 is normally lowered into lower casing 26 , then radially expanded and pulled upward. Several techniques for expanding pig 70 are known in the art, such as in U.S. Pat. No. 7,195,061, for example. As the lower casing segment 26 is radially expanded by the pig 70 , a portion of the lower casing segment 26 that overlaps with the overlap region 32 of the upper casing 28 is deformed onto the wicker profile 40 ( FIG. 3 ) to form a metal-to-metal seal. The wicker profile 40 bites into the exterior surface 38 of the lower casing segment 26 that is within the overlap region 32 as previously shown in FIG. 3 . The inner diameter of the overlapping portion of lower casing will be the same or approximately the same as the inner diameter of the non-overlapping portion of the upper casing 28 . Optionally, the entire length of lower casing 26 could be expanded, rather than just the one overlapping portion. If the entire length is expanded, the resultant inner diameter will equal or nearly equal the inner diameter of upper casing 28 . [0020] The exterior surface 38 of the lower casing may be formed of a softer metal than that of the wickers 40 or wickers 40 may contain an inlay of soft metal. Further, the wickers 40 may be formed from a different type of metal that is harder than that of the rest of the upper casing 28 , such as Inconel® 725. The yield strength of carbon steel casing is approximately 55 to 110 ksi, depending on the application. The wickers may have 120 ksi minimum yield strength and a hardness can vary between roughly less than 20 Rockwell C (“HRC”) to greater than roughly 37 HRC. The higher hardness of the wickers 40 ensures biting into the lower casing 28 overlap region. In addition, any portion of the lower casing segment 28 that remains above the overlap region 32 may be cut-off and removed, if desired. No additional sealing or pachoffs are required. The procedure described above may be repeated to install additional liner strings. Further, each metal-to-metal seal formed may be tested by pressurizing the interior of the casing and observing any drop in pressure. [0021] While the invention has been shown in only one of its forms, it should be apparent to those skilled in the art that it is not so limited but is susceptible to various changes without departing from the scope of the invention.	Casing segments and an expansion cone are positioned and cemented within a new section of a wellbore with a lower casing segment in an overlapping relationship with an upper casing segment. The lower casing segment is radially expanded such that an upper end of the lower casing segment comes into contact with the interior wall of the upper casing segment at the overlap region. The upper casing segment has an inward facing profile at the overlap region that includes a set of wickers that are driven into the lower casing exterior when it is expanded. This forms a metal-to-metal seal between the upper and lower casing segments at the overlap region.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention broadly concerns a forming panel used in forming wall structures of hardenable concrete, whereby multiple panels may be placed in adjacency and in opposition for receiving and supporting the concrete pour therebetween. More particularly, it is concerned with a concrete forming panel which includes a flexible barrier positioned adjacent and preferably aligned with a margin on the forming panel such as a perimeter edge or on an interior edge to inhibit the flow of the concrete mix therepast. [0003] 2. Description of the Prior Art [0004] The formation of building walls, foundations and other wall structures from poured concrete after curing is well known and the forms used for holding the concrete fall into two general categories. Forming walls may be made of site-built forms, typically of plywood, and are used only once before being discarded, or of reusable forming panels, typically of wood, steel or aluminum or combinations thereof, which panels may be fastened together and then removed from the hardened concrete wall for reuse. While these reusable forming panels are typically of a greater initial cost, their ability to be repeatedly used more than compensates for the initial expense. [0005] The reusable forming panels typically have a face plate supported by a frame and are joined together in adjacency (essentially side-by-side or angled) to provide a form wall, and two form walls oppose one another to receive the concrete therebetween. Each forming panel may have a number of relieved areas along the side to receive tie bars for connecting the opposing form walls. Where the panels meet along their perimeters, small gaps are present, especially in the relieved areas not occupied by a tie bar. Moreover, the panels may have interior holes or openings which are penetrated interiorly of the perimeter of the forming panel by tie bars, rods or the like, and there are similar gaps between the tie bars and the surrounding forming panel. The concrete is mixed with water to make it flowable and ready to pour, the concrete mix typically including water, fine particles of mortar and sand, and aggregate such as gravel. In the gaps along the perimeter of the forming panels and where there are openings on the interior of the forming panel, water and fine particles of sand and mortar of the wet concrete will typically migrate from the concrete pour during curing. As a result, the appearance of the cured and hardened concrete opposite these gaps will be discolored, and will typically have significant raised ridges and be pitted rather than smooth as appears along the face of the forming panel. The large ridges and the pitted area along the face may affect not only the appearance but also the performance of the concrete wall over time. SUMMARY OF THE INVENTION [0006] These problems are significantly ameliorated by the concrete forming panel provided with a flexible barrier in accordance with the present invention. By the provision of a flexible barrier along and proximate to one or more margins in the forming panel which engage flowable concrete during curing, such as the face plate and frame, a substantial reduction in the loss of fine mortar particles and water is achieved. This results in a finished wall surface with substantial reduction of discoloration and pitting, even in the relieved tie bar passage area or interior openings. The flexible barrier serves as a gasket which yields for variations in the size of the gaps as well as permitting tie bars and other forming accessories to abut and pass thereby, and stands up to rugged use environments. Moreover, when the panel has an opening within the perimeter of the face plate and rails of the frame, by providing an interior margin provided with such a barrier within the perimeter of the forming panel, the forming panel hereof substantially reduces the problem of large ridges and pitting where tie bars and other forming hardware must pass through openings in the frame inside of the perimeter. An additional benefit is reduced seepage of moisture into and through the hardened wall structure. [0007] In greater detail, the forming panel with flexible barrier along one or more of its margins broadly includes a form configured to receive a pour of a flowable concrete mix in supporting relationship thereagainst, the forming panel in a face plate typically of aluminum and a frame also of aluminum or steel having at least one siderail. The frame typically includes parallel and spaced apart, opposed endrails, siderails in spaced relationship and extending parallel thereto, and crossbraces, end reinforcements and gusset plates. The rails have exposed edges and face plate edges, with elongated grooves provided in the rails (both endrails and siderails) on the exterior side thereof. Flexible barriers acting as gaskets, preferably of filaments such as brush strips, are received in the grooves to impede the migration of water and fine particles of the concrete mix therepast as the barriers engage opposing parts of the forming panel or adjacent forming panels. The brush fibers of the brush strips are preferably oriented at an angle toward the concrete-receiving surface of the face plate and extend beyond the outer surface of the frame, whereby when the barrier is engaged by another component of the forming panel, a tie bar, another forming panel or an opposing barrier, the brush fibers project toward the concrete mix in the pour and the face plate rather than away to minimize the amount of water and fine mortar and sand particles of the mix carried into the gap between forms. Alternately, or in addition to the flexible barrier positioned near the perimeter margin of the forming panel, openings within the face plate may have flexible barriers mounted in proximity. The openings within the face plate may be substantially covered by a shiftable door which may be hinged, so that when there is no need to pass a tie bar therethrough, the door may be sealed. On the other hand, opening the door greatly facilitates placement and coupling of a tie bar to the forming panel, and closing of the door still permits a tie bar to pass thereby. The flexible barrier may be provided on either the door or a reinforcing enclosure around the opening, or both. The door is preferably hingably mounted to the reinforcing enclosure and a closure member provided to hold the door closed. A narrow gap may be provided between the door and the face plate when the door is in a closed position, to thereby permit the tie bar to pass therethrough when the door is closed, the barrier element helping to seal the gap. [0008] As a result, forms are provided which substantially reduce the amount of discoloration and pitting in the finished wall surface, minimize the formation of ridges of material migrating into the gaps between forms, and provide an improved finished concrete surface while remaining rugged in use. These and other advantages will be appreciated by those skilled in the art with reference to the drawings and description which follow. BRIEF DESCRIPTION OF THE DRAWINGS [0009] [0009]FIG. 1 is a rear perspective view of a concrete forming panel in accordance with the present invention, showing the face plate and the frame, with a flexible barrier extending around the siderails and endrails of the frame parallel to and adjacent the perimeter of the forming panel; [0010] [0010]FIG. 2 is an enlarged, fragmentary perspective view showing a siderail and face plate in section and a relieved area for the passage of a tie bar, with the flexible barrier shown in an exploded view; [0011] [0011]FIG. 3 is an enlarged fragmentary horizontal sectional view through a sidewall and the face plate showing the orientation of the tips of the fibers of the flexible barrier oriented at an acute angle to the plane in which the face plate lies; [0012] [0012]FIG. 4 is an enlarged, fragmentary vertical sectional view through a portion of the face plate and showing a coupler pin and wedge for holding together two forming panels in side by side relationship and with a tie bar shown in broken lines; [0013] [0013]FIG. 5 is an enlarged, fragmentary cross-sectional view taken through line 5 - 5 of FIG. 4, showing the orientation of two opposed flexible barrier elements of adjacent forming panels extending into the gap therebetween; [0014] [0014]FIG. 6 is an enlarged, fragmentary cross-sectional view taken through line 6 - 6 of FIG. 4, showing the orientation of the two opposed flexible barrier elements when compressed by a tie bar received in the relieved area and passing through the gap; [0015] [0015]FIG. 7 is an enlarged, fragmentary cross-sectional view similar to FIG. 6, showing the relieved area adapted to receive the tie bar as in FIG. 6, but in the condition when a tie bar is not placed therethrough, with the flexible barrier elements engaging one another in the gap; [0016] [0016]FIG. 8 is a rear elevational view of another aspect of the forming panel of FIG. 1, showing the portion of the forming panel which is provided with an opening in the face plate interior to the perimeter of the face plate and the side rails and end rails of the frame and having a reinforcing enclosure around the opening and a door for substantially closing the opening; [0017] [0017]FIG. 9 is an enlarged, fragmentary cross-sectional view taken along line 9 - 9 of FIG. 8, showing two opposed forming panels of opposite forming walls positioned and connected by a tie bar for receiving flowable concrete in the channel therebetween, one of the panels being shown in plan, and the tie bar passing between the forming panels through the opening and a barrier element in both the enclosure and the door of the forming panels; [0018] [0018]FIG. 10 is an enlarged, fragmentary elevational view in partial cross-section along line 10 - 10 of FIG. 9, showing the combination pin fastener and door retainer in a first position holding the door closed and passing through a hole in the tie bar; and [0019] [0019]FIG. 11 is an enlarged, fragmentary elevational view in partial cross-section as in FIG. 10, but with the combination pin fastener and door retainer retracted and retained in a second position where the hinged door is open to facilitate insertion of the tie bar or removal of the forming panel. DESCRIPTION OF THE PREFERRED EMBODIMENT [0020] Referring now to the drawing, a concrete forming panel 10 in accordance with the present invention broadly includes a face plate 12 typically of aluminum and a frame 14 mounted along the perimeter 15 of the forming panel 10 , also preferably primarily of aluminum by welds 17 . As used herein, “aluminum” refers to aluminum alloys, such as, for example, ASTM 6061 T-6 alloy, and the face plate, and a typical thickness of aluminum sheeting used as a face plate 12 would be about 0.125 inch. The frame 14 preferably includes a pair of elongated endrails 16 and 18 and a pair of opposed siderails 20 and 22 , which in the illustrated embodiment the siderails are shown parallel to each other and perpendicular to the endrails, although it may be appreciated that it is possible for the forming panel to be in various geometries and have arcuate edges. A typical endrail or siderail of aluminum has a thickness of about ⅜ inch. The frame may include cross-braces 24 , and end braces, gusset plates at the corners, and steel bushing plates or reinforcements to reinforce holes 26 spaced along the siderails 20 and 22 which receive therethrough coupler pins 28 secured by wedges as shown in FIGS. 4, 5 and 6 , with such steel reinforcing members positioned adjacent the holes 26 for wear resistance. The face plate 12 lies in a plane and is shown flat and smooth, although textured surface face plates 12 may be used as well. [0021] A barrier element 30 of flexible material such as rubber or more preferably brush strips 32 of nylon fibers or bristles 34 secured by metal retaining clips 36 is received in longitudinally extending slots 38 in the siderails 20 and 22 and the endrails 16 and 18 . The slots 38 are located more proximate the face plate edge 40 of the siderails and endrails than the back side exposed edge 42 of the siderails and endrails. The siderails and endrails each have an outer surface 44 and an inner surface 46 , the slots 38 being in communication with the outer surface 44 as shown in FIGS. 2 and 3. The slots 38 are most preferably provided at an acute angle φ relative to the face plate 12 so that the bristles 34 extend forwardly toward the face plate edge 40 of the siderails and endrails. The bristles 34 are also of a sufficient length relative to the depth of the slots 38 that they project beyond the outer surface 44 . The slots 38 are preferably positioned in a thickened region 48 of the siderails and endrails as shown in FIG. 3 in order to avoid weakening of the siderails and endrails. [0022] The siderails 20 and 22 are not of constant thickness along their longitudinal length, but rather their outer surface 44 is provided with longitudinally spaced, laterally extending relieved areas 50 adjacent unrelieved areas 51 , the relieved areas 50 providing passages for tie bars 52 to be placed thereon and in the gaps between adjacent forming panels 10 as shown in FIGS. 6 and 7. The tie bars 52 are used to separate and hold at a predetermined distance an opposite forming wall of other forming members in order to provide a channel 126 therebetween for receipt of a pour of flowable concrete 54 therein. An adjacent relief 56 is also provided in the face plate 12 . As may be seen in comparing FIG. 5 showing two adjacent forming panels 10 in side-by-side relationship in cross-section taken through the siderails 20 and 22 of adjacent forming panels 10 with FIG. 6 taken in cross-section through the siderails 20 and 22 and the tie bar 52 , the depth of the slots 38 are slightly less in the vicinity of the relieved areas 50 so that the tips of the barrier element fibers are substantially linear thus equidistant in a direction perpendicular from the outer surface 44 at the unrelieved areas 51 and exposing slightly more of the barrier element fibers in the relieved areas 50 than the unrelieved areas. Because the slots 38 are oriented on an axis that is at an acute angle φ relative to the plane in which the face sheet 12 lies, the resulting forward angled orientation of the bristles 34 toward the face plate 12 , the engagement of opposed flexible barriers 30 with a tie bar 52 or with the barrier element 30 of an adjacent forming panel 10 causes the bristles 34 to slightly bend in a forward direction as shown in FIGS. 5 and 6. This in turn enhances the performance of the barrier element 30 by providing both a greater density of concentration of the bristles 34 where they interengage and also extending them forwardly to reduce the region into which water and particles from the concrete pour may migrate and lessen the extent of any ridge which may be formed as the concrete flows in to the gap 58 between the adjacent forms 10 . As shown in FIG. 7, the bristles 34 of the barrier elements 30 are particularly helpful where there is no tie bar 52 positioned in a relieved area 50 , which would otherwise present an even wider opening between the adjacent forming panels 10 . The barrier elements 30 are preferably mounted all around the forming panel 10 on each of the rails in an orientation parallel to and closely adjacent the perimeter of the face plate 12 . [0023] [0023]FIGS. 1 and 8- 11 illustrate an alternate embodiment where, in addition or as an alternative to the flexible barrier element 30 provided in the frame 14 around the perimeter of the forming panel 10 , an opening 60 is provided in the face plate 12 inside the frame 14 and thus interiorly of the perimeter. A closure and support element 61 is attached to the face plate 12 adjacent the opening, shown as a reinforcing enclosure 62 of aluminum which surrounds and thus reinforces the opening and is attached to the face plate 12 or the cross members by welding, fasteners or the like. The enclosure 62 includes a base 64 which mounts to the face plate 12 by welding or the like to support and reinforce the face plate 12 surrounding the opening 60 and two spaced-apart gates 66 and 68 , each having a respective passage 70 and 72 therethrough. A reinforcing rod 74 of hard steel, such as ASTM 228-93 wire, is received in a groove 76 adjacent the passages 70 and 72 and the deformation of the aluminum alloy caused by drilling the passages serves to pinch or hold the rod 74 in place. The reinforcing rod 74 helps to resist wear on the gates 66 and 68 and prevent enlargement of the passages. The base 64 may include a slot 78 adjacent to and facing the opening for receipt of a flexible barrier element 30 therein. Again, the flexible barrier elements may be rubber or more preferably brush strips 32 of nylon bristles 34 held by metal clips. [0024] A hinge 80 is provided on the base 64 for pivotally mounting a door 82 . As illustrated by FIG. 9, the door 82 may swing between a first position substantially but not completely closing the opening 60 and a second position which is open. The door 82 includes a head 84 and an insert 86 which fits within the opening 60 . The head 84 presents a lip 88 which engages the base 64 and has a reinforcing rod 74 received in a groove 90 therein. The head 84 is sized to provide a slot 92 between the head 84 and the base 64 to permit passage of a tie bar 52 . [0025] The door 82 is held closed by closure mechanism 94 . The closure mechanism 94 is mounted on arm welded to the face plate 12 or to a cross-brace 24 of frame 14 . The closure mechanism 94 includes a housing 96 , a pin 98 shiftably received in the housing 96 , and a catch 100 . As illustrated in FIGS. 10 and 11, the pin 98 is biased toward the gate 66 by a coil spring 102 received within the housing. The pin 98 includes a shank 104 slidable within the housing 96 , a narrowed neck 106 , and a nose 108 which is rounded at its tip. Both the nose 108 and the shank 104 have a greater diameter than the diameter of the neck 106 . The catch 100 includes a bar 110 which is mounted by a hinge 112 for toggling on pivot mount 114 . The bar 110 has a first end 116 which is engaged on its underside by a spring 118 extending from the housing 96 and a second end 119 which has a cradle 120 which includes an arcuate web 122 sized to receive the neck 106 but not the shank 104 therein. Thus, the spring 118 biases the cradle 120 toward the pin 98 . [0026] In use, the forming panel 10 , shown individually in FIG. 1, is coupled to adjacent forming members, such as another forming panel 10 as shown in FIGS. 5,6 and 7 , to provide one forming wall 122 , and another forming wall 124 is positioned opposite as shown in FIG. 9 so that a channel 126 for receiving flowable concrete 54 is therebetween. Tie bars 52 are placed in at least some of the relieved areas 50 , though typically not all of them and extend through the channel to connect the forming walls 122 and 124 when connected to the forming panels by pins 28 . Adjacent forming panels are connected by pins 28 held in place by wedges as shown in FIGS. 4, 5, 6 and 7 , with these pins 28 passing through holes in the tie bars 52 to hold them in position. The tie bars extend across and through the channel 126 for connecting the opposing forming walls 122 and 124 , whereby after the concrete 54 cures, the tie bars 52 remain embedded in the concrete wall structure formed thereby. [0027] In addition, door 82 may swing open to facilitate positioning of a tie bar 52 through the opening 60 in opposing forming panels 10 . The pin 98 is first retracted against the coil spring 102 and the catch is released whereby the web 122 of the cradle 120 rests around the neck 106 and against the shank 104 to hold the pin 98 in a retracted position. The tie bar 52 is then aligned to lie closely adjacent the gate 66 , whereupon the door may be closed to substantially block the opening 60 . With the door closed, the operator presses on the first end 116 of the catch 100 to release the spring loaded pin 98 . The pin 98 then passes through the hole of the tie bar 52 and through the gate 66 to both hold the door 82 in the closed position and secure the forming panel 10 to the tie bar 52 . Thereafter, dry concrete mixed with water may be poured into the channel 126 , which after a suitable curing period, hardens. The barrier elements 30 substantially inhibit the flow of water and fine particles of mortar, sand and the like from the concrete 54 while it cures. The barrier elements 30 along the side rail and end rail edges oppose one another as shown in FIG. 5 to inhibit substantial flowing of material without inhibiting the performance or coupling ability of the forming panels. The bristles 34 yield when engaged by tie bars 52 or the frame 14 and being separate, resist tearing, while providing a substantial barrier to the flow of water and fine particles from the concrete. The flexible barrier elements are especially beneficial in resisting flow of water and fine particles both when a tie bar 52 is present in a relieved area 50 or, even more importantly, when a tie bar 52 is not used in a relieved area as shown in FIG. 7. When an opening 60 is provided in the forming panel interiorly of the perimeter provided by the frame, the door 82 is able to swing open to ease the placement of the tie bar. After the tie bar 52 is in place, the door may be closed to inhibit the flow of concrete or the water and fine particles thereof through the opening 60 . The flexible barrier elements 30 in the base 64 and the door 82 further limit the migration of water and fine particles through the slot 92 . The first end 116 of the bar 110 is depressed to release the cradle, whereupon the coil spring 102 pushes the pin 98 through the gate 66 so that the nose of the pin 98 rests against the head of the door 82 to hold the door in a closed position. [0028] After the concrete 54 cures and hardens, the forming panels 10 may be readily removed for reuse by removing the wedges from the coupler pins 28 and pulling the coupler pins through the holes 26 in the rails. The pin 98 is retracted so that the cradle engages the neck of the pin 98 to permit opening of the door 82 . This also disengages the pin 98 from the tie bar 52 , permitting the forming panels 10 to be removed. The barrier elements 30 substantially limit the migration of water and fine particles from the concrete 54 as it hardens and thus inhibits the formation of substantial ridges opposite the gaps between forming panels. A smoother surface of the resulting wall with substantially less pitting results from the use of the barrier elements both around the perimeter edge of the forming panels 10 and at any interior openings. [0029] Although preferred forms of the invention have been described above, it is to be recognized that such disclosure is by way of illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention. [0030] The inventor hereby states his intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of his invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set out in the following claims.	A forming panel and method for using the same in construction of self-sustaining concrete wall structures is provided wherein a flexible barrier element is provided along a margin on the forming panel for impeding the flow of water and fine particles of a concrete mix pour past the barrier element. The margin may be along the perimeter edge of the forming panel or along an opening interior to the perimeter of the forming panel. When located near the perimeter, the flexible barrier element may be positioned in a slot extending parallel to the margin and located in the frame. When located near an interior opening, the barrier element may be provided on a reinforcing member positioned around the opening or on a door which shifts to improve access through the opening during placement of forming ties or the like. The forming panel may be coupled with adjacent forming members to provide a wall system, and two wall systems may be connected by forming ties to provide a channel for receipt of a concrete pour therebetween.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION This invention relates to a knock-down portable wall structure constructed of releasable wall elements. It is often desired to construct enclosures within a room to define individual work spaces and the like. It is preferred that these enclosures be dismantleable rather than becoming a permanent part of the building. Various partitions have heretofore been known but do not possess all the features that are desired, namely, the use of wall portions that are attractive in appearance, that are rugged in construction, that have ease of assembly and disassembly, and that have versatility in shaping and sizing for an area to be enclosed. SUMMARY OF THE INVENTION An object of the invention is to provide a portable work space wall structure that overcomes deficiencies in prior devices in that it possesses all the features of being attractive in appearance, rugged in construction, easy to assemble and disassemble, and versatile in shaping the work space to be enclosed thereby. A more particular object is to provide a wall structure of the type described that uses novel lock pins, associated lock cavities, and locking lugs that readily secure wall elements together in a positive manner without exterior connectors and also in a simplified manner. The lock means also provide ready disconnection for disassembly of the wall structure. Yet another object is to provide a wall structure of the type described that is simplified in construction and inexpensive to manufacture. In carrying out the objectives of the invention, cavities extend inwardly through the side edges of at least one of a pair of wall members in corner or edge trim elements of the wall structure and through both side edges of adjacent wall panel elements in wall expanse portions. In each case, lock pins are provided between the wall elements for each of the cavities and are associated with locking lugs in inner portions of the cavities that have snap-in locking engagement with the lock pins for securely attaching the two wall elements together. The cavities have a leveraging surface capable when engaged by the lock pins of pivoting them out of engagement with the locking lugs. Such leverage function is achieved by relative movement of two adjacent wall elements to cause the detachment of the two wall elements. In the corner or edge trim connections, the lock pin has one end secured to the corner or edge trim element at right angles thereto and its other end extends into the cavity for releasable locking association with the locking lug. In adjacent wall panel elements, double ended lock pins are used that have releasable locking connection at their opposite ends for securely attaching two wall panel elements together. The invention will be better understood and additional objects and advantages will become apparent from the following description taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a work space which can be readily formed by the present invention. FIG. 2 is a fragmentary sectional view of a corner portion of a wall panel, this view being taken on the line 2--2 of FIG. 3 and showing a first form of lock pin in locked position. FIG. 3 is a fragmentary elevational view of an edge of a wall panel, taken on the line 3--3 of FIG. 2. FIG. 4 is a fragmentary sectional view taken similar to FIG. 2 but showing a second form of lock pin, this view showing the pin in locked position. FIG. 4a is a view similar to FIG. 4 but showing the lock pin in the process of being unlocked, and FIGS. 5, 6 and 7 show assorted structural shapes at edge trim or corners of the wall panels. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS With particular reference to the drawings, and first to FIG. 1, the wall structure of the invention resides broadly in component wall panels 10 that can be combined in various ways to form inner work spaces of desired shapes and sizes. As an example, the panel system can be free standing or anchored to a wall or other structural member. FIG. 1 represents a simplified work space that can be readily formed by an assemblage of elements of the invention. Basic to the invention are the multiple wall panel elements 10 which have opposite surfaces 10a, also seen in FIG. 3, usually covered with a suitable attractive material having sound absorbent qualities. The panel elements 10 may be hollow core, acoustical core, or suitable other structure. A hollow core structure is illustrated structured with an interior frame 11. They have a top cap strip 10b and vertical narrow strip or trim elements 10c connected to those edges at doorways, wall ends, or other terminal edges. The edges of the panels at corners have connecting strip elements 10d. Wall elements 10c and 10d are secured releasably to the panels 10 by a single end lock pin, and adjacent edges 10e of wall panels in a wall surface are secured releasably by double end lock pins, to be described. Each wall panel element has a selected number of edge cavities 12, FIGS. 2, 3 and 4, that lead in through the side edges of the frame 11 adjacent the top and bottom thereof at right angles and that open interiorly in an enlarged recess or open area 14, also seen in FIG. 1. Two of such cavities adjacent the corners usually will suffice. The cavities 12 are vertically elongated in somewhat of an oval shape as seen in FIG. 3 at an inner portion 12a of the cavities. The top and bottom defining walls of cavity portion 12a are parallel with each other. An outer portion 12b thereof tapers to an enlarged dimension opening at the edge. The joining point 12c between wall portions 12a and 12b forms a fulcrum or leveraging point therebetween, as will be more apparent hereinafter. Fulcrum point 12c is approximately longitudinally centered in the cavity. A rigid, thin locking lug 16 is secured integrally as by fastener means 18 to a wall of the recess 14 and in position to overlap the cavity 12 a short distance from the top of the cavity. As will be seen, lug 16 forms a catch for lock pins 20 and 20', FIGS. 2 and 4, respectively, and is associated with leaf spring retainers 22 that force the lock pins into a positive but releasable engagement with the locking lugs. The retainers 22 partially overlap the adjacent portion of the cavities and have angled ends 24 slidably engageable with the lock pins. The FIG. 2 form of the lock pin, comprising a single end lock pin, is for securing an edge trim element 10c or corner element 10d, removably to the panels 10. The lock pin 20, FIG. 2, has a base end 28 that is securely fixed to trim element 10c for holding the lock pin at right angles to the element 10c. The lock pin has a tapered head end 30 that is engageable by the angled end 24 of the spring retainer 22 which firmly holds the pin upward toward the lug 16. The head end of the pin has a circumferential groove 32 in its body portion spaced a short distance from the tapered end 30. This groove is of a width that receives the lug 16 but at the same time with minimum play to prevent any substantial longitudinal play of the lug therein. A base portion of the lock pin adjacent its secured portion has top and bottom cross grooves 34 that weaken the body portion at this point to form a hinge that assists in separating the pin from the locking lug, to be described. The pin 20 is preferably round and has a diameter only slightly less than the width of the cavity 12 at the wall portion 12a, FIG. 3. The FIG. 4 double end form of lock pin 20' is for releasably securing two wall panels 10 together in direct edge to edge engagement 10e. In this form, the lock pin also is round but has a head 30 on each end for locking engagement with locking lugs 16 in adjacent panels. The heads similarly have a circumferential groove 32 adapted for locking engagement with lugs 16, and the lock pins also have association with their respective cavities the same as was described in connection with pin 20. The structure and dimension of the lock pins 20 and 20' are critical. They are formed of a material preferably plastic that is tough, substantially rigid in at least portions thereof so as to be capable of being operated as a lever. Also it is preferred to use a plastic that will not become brittle with age and that has a lubricating surface. The length dimension of the lock pins is such that when the single end structure of FIG. 2 has been inserted into cavity 12 to a point that substantially fully penetrates cavity portion 12a, the head end will ride over and snap into engagement with the lug 16. The pin then tightly holds the panel to the end trim element 10c. In the FIG. 4 double end structure, when the two opposite ends of the lock pin are fully inserted into their respective cavities, the heads engage the lugs of the two adjacent panels and the latter are held tightly together. In snapping the panels together as in FIG. 4 or connecting a panel to the edge strip 10c as in FIG. 2, it is merely necessary to move two of the members edgewise together such that the lock pins penetrate the cavity and snap into engagement with the lug 16. Spring retainers 22 ensure that the heads 30 obtain a positive lock connection as well as to hold the lock secure. Cavity portions 12a are slightly larger vertically than the diameter of the lock pins. The pins thus have some vertical play but only minimal, for example, a fraction of an inch, top and bottom. Such vertical play is to allow proper locking of the lock pins to the lugs 16 as well as to allow unlocking thereof, to be described. The lateral dimension of the cavities, at both its portions 12a and 12b, is substantially the same as the diameter of the pins but with a slight clearance wherein the pin can be readily inserted but at the same time is fairly snug from side to side. Thus, there will be no appreciable side to side play of adjoining panels or of edge or connecting strip elements. In addition to vertical support of adjoining panels on a supporting surface for precise vertical alignment, the lock pins are firmly held in engagement with the lugs 16 by the retainers 22 and also prevent relative vertical movement. To disconnect the trim element 10c of FIG. 2 from the panel 10 or corner 10d from a panel or to disconnect direct edge adjoining panels 10, FIG. 4, each of the lock pins 20 or 20' will release from its lug 16 when it is leveraged against the fulcrum point 12c of the cavity that is on the lug side of the lock pin. That is, in FIG. 2 for example, the strip 10c is detached by grasping it and forcing it upwardly relative to the panel 10 an amount sufficient to cause pin 20 to engage the top of the cavity and more particularly to engage the fulcrum point 12c. Continued movement of the strip 10c leverages the lock pin out of engagement with the lug 16 and strip 10c and pin are thus released. In view of the short length of pin 20, cut-out portions 34 provide sufficient hinge length distortion of the pin relative to its base to allow it to release from its lug 16. The lock pins in adjoining panels, FIG. 4, have similar leverage action in their release as do the lock pins 20 but do not require the intermediate hinge 34 as in FIG. 2. With reference to FIGS. 5, 6 and 7, various arrangements of wall structures are available with the use of the instant invention. FIG. 5 illustrates an end trim element 10c on a panel 10, as detailed in FIG. 2. FIG. 6 illustrates a further arrangement of wall panel elements wherein a connecting member 10f has three usable sides such as for holding a partition wall 10g. FIG. 7 illustrates a corner element 10d also shown in FIG. 1. Such a corner member and the partition corner 10f are of a dimension to include lock pins 20 mounted on each of the angled surfaces therefor for releasably engaging panels in a manner similar to that of the trim element 10c in FIG. 2. If desired, the top cap 10b can have a similar removable connection to the wall panels 10 as do the trim elements 10c or corners 10d and would be releasable from the wall panels by relative horizontal movement. According to the invention, connector means are used that are concealed when in use. Also, these connector means are efficient in operation in that to connect members of the assembly, such members are merely moved together with a sufficient force to snap the pins 20 or 20' into engagement with the lugs 16. The connector parts are exact so that the various wall elements appear to be permanently attached. With the elements as disclosed herein, substantially any shape and size of area can be enclosed. Knock-down of an assembly is readily accommodated by the relative vertical movement of the elements as described. It is to be understood that the forms of our invention herein shown and described are to be taken as preferred examples of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of our invention, or the scope of the subjoined claims.	Wall elements have edge cavities that extend inwardly through their side edge and have locking lugs inwardly of the cavities. Lock pins are provided between the wall elements for each cavity and are associated with the locking lugs for securely locking two wall elements together by moving the wall elements into edge-to-edge abutting relation. The cavities have a leveraging surface capable of pivoting the lock pins out of engagement with the locking lugs and thus disconnection of the wall elements upon relative vertical movement of adjacent wall elements. The invention is capable of assembling knock-down walled enclosures such as work spaces of substantially any size and shape.
You are an expert at summarizing long articles. Proceed to summarize the following text: This patent application claims priority to U.S. provisional patent application Ser. No. 61/502,523, filed Jun. 29, 2012, the disclosure of which is incorporated herein by reference. BACKGROUND OF THE INVENTION Earthquake tremors (and damage caused by such tremors) are the result of three basic types of elastic wave caused by the slipping of plates in the earth's crust against each other; two of these waves are capable of traveling through rock. The first of these three waves is the primary or P wave; this wave is a compression wave and propagates linearly in the direction of travel through rock and fluid; this is the fastest traveling seismic wave. The secondary or S wave generally moves more slowly than the P wave and its wave movement is at right angles (up and down, and/or side-to-side) to the direction of travel. It is the S wave that causes most damage to structures. The third type of wave is called a surface wave, and is restricted to the ground surface. This type of wave has a motion similar to ripples on the surface of water. There are two types of surface waves. The first is called a Love wave and is similar to that of an S wave having a side-to-side motion with little or no vertical displacement; these waves can cause substantial damage to objects since virtually all the energy is employed within a horizontal plane. The second type of surface wave is called a Rayliegh wave, which is like an ocean wave and can cause displacement in both the vertical and horizontal plane relative to the direction of travel. P and S waves have a characteristic which further affects shaking: when these waves move through layers of rock in the crust they are reflected or refracted at the interfaces between rock types. Whenever either wave is refracted or reflected, some of the energy of one type is converted to waves of the other type. For an example, as a P wave travels upwards and strikes the bottom of a layer of alluvium, part of its energy will pass upward through the alluvium as a P wave and part will pass upward as the converted S-wave motion. This means that the direction of shaking (e.g., left to right, front to back, or diagonally) in a given location is usually not entirely predictable, as it is dependent upon factors including the direction of wave travel and the nature (such as the density and homogeneity) of the crust in the general location in which the shaking is to be experienced. This in turn depends upon the location of the fault whose rupture has caused the waves. Two approaches have been traditionally utilized to prevent or limit damage or injury to objects or payloads due to seismic events. In the first approach, used particularly with structures themselves, the objects or payloads are made strong enough to withstand the largest anticipated earthquake. However, in addition to the relative unpredictability of damage caused by tremors of high magnitude and long duration and of the directionality of shaking, use of this method alone can be quite expensive and is not necessarily suitable for payloads to be housed within a structure. In the second approach the objects are isolated from the vibration such that the objects do not experience a major portion of the seismic waves. In certain cases, isolation flooring, for example “earthquake isolation flooring”, has been used or proposed. Such flooring has generally comprised a combination of some or all of the following features: a sliding plate, a support frame slidably mounted on the plate with low friction elements interposed therebetween, a plurality of springs and/or axial guides disposed horizontally between the support frame and the plate, a floor mounted on the support frame through vertically disposed springs, a number of dampers disposed vertically between the support frame and the floor, and a latch to secure the vertical springs during normal use. Certain disadvantages to such pre-existing systems include the fact that it is difficult to establish the minimum acceleration at which the latch means is released; it is difficult to reset the latch means after the floor has been released; it may be difficult to restore the floor after it has once moved in the horizontal direction; the dissipative or damping force must be recalibrated to each load; there is a danger of rocking on the vertical springs; and since the transverse rigidity of the vertical springs cannot be ignored with regard to the horizontal springs, the establishment of the horizontal springs and an estimate of their effectiveness, are made difficult. Ishida et al., U.S. Pat. No. 4,371,143 have proposed a sliding-type isolation floor that comprises length adjustment means for presetting the minimum acceleration required to initiate the isolation effects of the flooring in part by adjusting the length of the springs. Yamada et al., U.S. Pat. No. 4,917,211 discloses a sliding type seismic isolator comprising a friction device having an upper friction plate and a lower friction plate, the friction plates having a characteristic of Coulomb friction, and horizontally placed springs which reduce a relative displacement and a residual displacement to under a desired value. The upper friction plate comprises a material impregnated with oil, while a lower friction plate comprises a hard chromium or nickel plate. Stahl (U.S. Pat. No. 4,801,122) discloses a seismic isolator for protecting e.g., art objects, instruments, cases or projecting housing comprising a base plate connected to a floor and a frame. A moving pivoted lever is connected to a spring in the frame and to the base plate. The object is placed on top of the frame. Movement of the foundation and base plate relative to the frame and object causes compression of the lever and extension of the spring, which then exerts a restoring force through a cable anchored to the base plate; initial resistance to inertia is caused due to friction between the base plate and the frame. Kondo et al., U.S. Pat. No. 4,662,133 describes a floor system for seismic isolation of objects placed thereupon comprising a floor disposed above a foundation, a plurality of support members for supporting the floor in a manner that permits the movement of the floor relative to the foundation in a horizontal direction, and a number of restoring devices comprising springs disposed between the foundation and the floor member. The restoring members comprise two pair of slidable members, each pair of slidable members being movable towards and away from each other wherein each pair of slidable members is disposed at right angles from each other in the horizontal plane. Stiles et al., U.S. Pat. No. 6,324,795 disclose a seismic isolation system between a floor and a foundation comprising a plurality of ball and socket joints disposed between a floor and a plurality of foundation pads or piers. In this isolation device, the bearing comprises a movable joint attached to a hardened elastomeric material (or a spring); the elastic material is attached on an upper surface of the ball and socket joint and thus sandwiched between the floor and the ball and socket joint; the bearing thus tilts in relation to the floor in response to vertical movement. The floor is therefore able to adjust to buckling pressure due to distortion of the ground beneath the foundation piers. However, the device disclosed is not designed to move horizontally in an acceleration-resisting manner. Fujimoto U.S. Pat. No. 5,816,559 discloses a seismic isolation device quite similar to that of Kondo, as well as various other devices including one in which a rolling ball is disposed on the tip of a strut projecting downward from the floor in a manner similar to that of a ball point pen. Bakker, U.S. Pat. No. 2,014,643, is drawn to a balance block for buildings comprising opposed inner concave surfaces with a bearing ball positioned between the surfaces to support the weight of a building superstructure. Kemeny, U.S. Pat. No. 5,599,106 discloses ball-in-cone bearings. Kemeny, U.S. Pat. No. 7,784,225 discloses seismic isolation platforms containing rolling ball isolation bearings. Hubbard et al., U.S. Patent Publication 2007/0261323, filed on Mar. 30, 2007 discloses a method and raised access flooring structure for isolation of a payload placed thereupon. Isolation bearings are disclosed in U.S. patent application Ser. No. 13/041,160 filed on Mar. 4, 2011, and Moreno et al., International Patent Application No. PCT/US11/27269, filed on Mar. 4, 2011. All patents, patent applications and other publications cited in this patent application are hereby individually incorporated by reference in their entirety as part of this disclosure, regardless whether any specific citation is expressly indicated as incorporated by reference or not. SUMMARY OF THE INVENTION The present invention is directed to vibrational isolation components, preferably of industrial guage, for aiding in the prevention of personal injury, equipment operating inefficiencies, and/or property damage due to displacement of industrial structures, heavy structures or valuable, expensive, and/or delicate objects and equipment (including, for example, computer equipment such as servers and hard drive arrays) during a seismic tremor or other vibration eliciting event. The equipment supported by this system may comprise, without limitation, industrial manufacturing, processing, or packaging equipment; assembly line components; computer components such as mainframe computers, computer components of robotic or semi-robotic equipment; electrical equipment such as dynamos and the like; laboratory and hospital equipment; hazardous chemical storage cabinets (thus preventing possible injury, explosion, fire, and the like); art works (such as, without limitation, sculptures and paintings); machinery; people; and the like. Collectively, the materials, objects and structures to be protected against damage or injury by the instant seismic isolation system will be referred to herein as the “payload”. The present invention thus provides heavy duty industrial vibrational isolation or flooring systems to attenuate or reduce the amount of vibrational energy or acceleration experienced by payloads. By “reducing” the vibration, vibrational energy, acceleration or displacement experienced by a payload is meant that such reduction is relative to that vibration, vibrational energy, acceleration or displacement experienced by an unisolated payload. Preferably the isolation system described and claimed herein, while supported by a foundation, slab (such as a cement or concrete slab or pad), or floor, is not a “raised” flooring system in the usual sense of the term, in that the preferred isolation system is not designed to provide access space under the support plate to create a hidden void for the passage of mechanical and electrical services such as cooling or heating systems, equipment connections such as power or data cables or conduit. Accordingly, unlike other systems that have been described, the current system is not designed using an underfloor substructure of adjustable-height or fixed supports or pedestals upon which the flooring rests. The term “pedestal” as used herein means an upward or downward projecting column, for example, of greater than about 6 inches, or of about 12 inches, or about 18 inches or about 24 inches or more, having an attached isolation bearing half (either upward- or downward-facing) joined at an end thereof and creating an access space under the support plate. By “foundation” is meant a base upon which the bottom portion of the isolation system of the present invention rests which is suitably strong enough to firmly support both the claimed industrial isolation system and the payload. Although not always the case, in one preferred embodiment the foundation upon which the isolation system is supported is positioned lower than the plane of the surrounding floor or base, such that a support plate or panel upon which the payload is placed is at substantially the same level or plane as the surrounding floor or base. In particularly preferred embodiments the foundation comprises or is comprised within a recess or a trench having a level lower than that of, and parallel to, the plane of surrounding floor or base. In a salient feature of the invention, the isolation system comprises or is supported by a strong frame (for example, a heavy duty frame using girder sections such as I-beam sections) upon which the bottom surface of a horizontal support plate or panel is installed and joined. The top surface of the support plate accommodates the payload to be isolated. The support plate is fabricated to have a high degree of integral strength, and to be resistant to bending or breaking under load. For example, the support panel or plate may be wholly or partially fabricated of one or more metal sheets. Alternative or additional materials comprising the support panel may include metal struts or beams, carbon fiber composites, fiberglass, wood, concrete, thermopolymers and thermopolymeric composites and the like. Although generally solid, the support plate or panel may in certain embodiments comprise an opening, for example, a grated or honeycomb-type structure, to reduce the weight without substantially sacrificing structural strength. The frame supporting the support panel or plate is in turn supported on the foundation, (e.g., concrete slab or pad) by a plurality of isolation bearings, each such bearing comprising a cavity defined by opposing recessed upper and lower bearing surfaces separated by and containing at least one rigid spherical ball. The weight of the payload on the isolation system is borne by these bearings comprising at least one concave or conical surface, each such bearing comprising a ball. Preferably the bearing is a ball-in-cone bearing or comprises a bearing surface comprising different cross-sectional shapes. The specific way in which the system is adapted to support the payload is subject to any of a number of variations, all such variations being encompassed within the present invention. In particularly preferred embodiments the cross-sectional outline of the bearing surface cavities comprises a composite shape containing at least one linear region. In other embodiments the cross-sectional outline of the bearing surface cavities comprises a composite shape containing at least one curved region. In the most preferred embodiments the cross-sectional outline of the bearing surface cavities comprises a composite shape containing at least one linear region and at least one curved region. The present isolation system is made to bear payloads ranging from several hundred pounds to several tons or more. In preferred embodiments the isolation platform is sufficiently strong to bear payload masses of a ton or multiple tons, or ten tons or more. By “payload masses” or “payload weight” is meant the combined mass of all objects placed upon the isolation system at one time. The payload generally comprises industrial equipment, such as manufacturing equipment, product processing equipment, packaging equipment, computer equipment such as servers and hard disk arrays, and/or the like. The payload may additionally or alternatively comprise structural components of a building or other such structure or part thereof. The invention is useful in the field of structural support and seismic stabilization, such as for payloads comprising heavy structures, buildings, bridges, and other large edifices. In presently preferred aspects, the invention is useful for supporting and stabilizing individual equipment, such as manufacturing, laboratory, computer, product processing and/or packaging equipment, computer equipment, and/or other valuable equipment from vibrations, including but not limited to seismic vibrations, which might otherwise damage such equipment. As indicated previously, a foundation may exist at a level other than a ground level. Without limiting the scope of the invention, often the foundation will comprise or be built upon a continuous concrete or other slab at a ground level of a structure or may be raised above ground level on a pad; in other embodiments a foundation may include a recess in the base or floor level so that the horizontal support panel indicated above may be substantially level with such base or floor level, as described further herein. The base or floor level may include a preexisting floor or slab or custom-made floor or slab, and this floor may be present at a ground level, below ground level, or a second or higher storey level of the building it is contained within. Thus in one preferred embodiment, the present invention comprises a seismic isolation system for supporting a payload comprising a seismic isolation system for supporting a payload comprising: a) a horizontally oriented support panel having a top surface and a bottom surface, wherein said support panel is structured to support the payload placed on the top surface thereof; b) a rigid frame joined to the flooring panel and structured to support said flooring panel and payload; c) a plurality of downward-facing isolation bearing halves joined to the bottom side of said first frame, wherein each downward-facing bearing half comprises a downward-facing recessed bearing surface; d) a plurality of seismic isolation footplates, each footplate comprising a upward facing bearing half comprising a recessed upward-facing bearing surface wherein each of said footplates is securely joined to a foundation and the upward facing recessed bearing surface of each of said footplates opposes a second, downward facing recessed bearing surface of a corresponding downward-facing bearing half and defines a cavity therebetween; e) at least one rigid ball located in each of such said cavities, said ball being structured to be sufficiently strong to maintain a gap between downward and upward-facing bearing halves during operation; and wherein, in the event of a seismic vibration each seismic bearing half moves relative to its corresponding opposing footplate thereby cushioning the payload from the full force of said seismic vibration. In one embodiment, the horizontal support panel comprises either a single panel sheet or a plurality of panel sheets. In this embodiment, the sheet may comprise one or more opening to reduce the mass of the panel, or it may be solid. The support panel may comprise a substantially homogenous material or mixture of materials, or may comprise layers of different materials (or mixtures of materials), such as in a laminate. Without limitation for example, the support pane may comprise one or more layers of any or each of a metallic alloy, wood, thermoplastic, glass wool, polymeric resin, carbon fiber and/or similar materials thus giving the support panel a high degree of strength and structural integrity—preferably while maintaining the mass of the support plate conveniently low. In a preferred embodiment of the present invention, the frame comprises a network of rigid, criss-crossing elongate support members and wherein each of the plurality of downward facing seismic isolation bearing halves is joined to the bottom side of the frame at an intersection of the elongate members. In an important, and preferred embodiment, the frame is made of structural members (such as I-beam segments) that are able to be connected in many ways, so that the isolation system of the present invention may be tailored to fit the required space and accommodate varying sizes and weights of payload to be isolated. I-beam segments are generally at least partly metallic, and may comprise iron, aluminium, titanium, carbon, tin, copper and/or various metal alloys such as steel. In a preferred embodiment, the frame is bolted to the bottom surface of the flooring panel. In another embodiment the frame may be welded to the bottom surface of the flooring panel. Seismic isolation bearings of the present invention comprise two generally identical recessed bearing surface halves: an upward facing recessed bearing surface comprised in or joined to a footplate, and a downward-facing bearing surface joined to the frame described above. Isolation bearings that are used to protect a payload from damage due to seismic vibration are typically configured to support an approximate minimum load, i.e., the weight of the structure being supported. In this regard, in certain embodiments it may be desirable that the rigid ball within the seismic isolation bearing be prevented from rolling out of the bearing during a particularly strong tremor in order to prevent failure of the bearing or damage to the payload being supported. Thus, in one embodiment of the present invention, at least one, and preferably both of the upward-facing and downward-facing recessed bearing surfaces has a circular rim adapted to prevent movement of said rigid balls out the corresponding cavities. In a preferred embodiment, the circular rims of each of a pair of upward and downward facing recesses do not contact each other in the resting position, when there is no seismic vibration. The lack of contact prevents frictional forces from being generated by the isolation bearing halves' movement relative to each other during use. The seismic isolation bearings of the present isolation system, with each bearing utilizing at least one rigid ball within a cavity formed within opposing upward and downward-facing recessed load bearing surfaces. The conservative character of the “rolling ball” type of isolation bearing of the present invention may be described in terms of the bearing's ability to absorb and store displacement energy caused by seismic activity or other external applied forces, thus cushioning the payload being supported from damage due to such displacement. It will be understood that such a rigid ball may itself be referred to as a bearing (such as a ball bearing), or the combination of the rigid ball and the supporting recessed bearing surface may together be referred to as a bearing. In this description generally the word “bearing” shall be reserved for the entire assembly; however, in certain occasions the context may make clear that the rigid ball itself is referred to as a bearing, such as through the use of terms such as “ball bearing”, “rolling bearing” or “spherical bearing”. The rigid balls are generally made of metal, such as stainless steel, but may be made of any sufficiently rigid material, including a polymer such as a plastic, a hard rubber, and the like. Those of ordinary skill in the art will be aware that a hard, rigid ball, such as a stainless steel ball, making contact with a bearing surface of similar rigidity, will make contact at a single point (thus at two points within the cavity of opposing recessed bearing surfaces), thereby having a minimum of energy lost to friction. Alternatively, if a measure of dampening is desired, one or more ball and/or one or more bearing surface may be made to have an increased coefficient of friction (such as with a surface coating of a pliable rubber, plastic or the like; or by making all or part of the ball or bearing surface out of such a dampening material). In one specific embodiment, the presently claimed invention comprises seismic isolation bearings in which the mass of the payload or a portion thereof is concentrated on a plurality of rigid balls placed between the upward-facing and downward-facing recessed bearing surfaces, at least one of which has a cross-sectional shape comprising at least one of an arc, a constant slope, or a parabola; preferably the cross-sectional shape comprises and at least two different curves or lines. Thus, in one embodiment of the present invention, the upward-facing and downward-facing recessed bearing surfaces are partially conical in shape. In a preferred embodiment, at least one of the upward-facing and downward-facing recessed bearing surfaces has a cross-sectional shape comprising a combination of conical and spherical shapes; a composite shape. In a preferred embodiment, the upward-facing recessed bearing surface may be identical to the downward-facing recessed bearing surface, but have an inverted orientation. Isolation platforms containing a variety of differently shaped load bearing surfaces bearings are disclosed in e.g., Kemeny, U.S. Pat. No. 5,599,106; 7,784,225 and US Patent Publication 2006/0054767; Isolation platforms comprising floors are disclosed in e.g., U.S. Pat. No. 7,290,375 and U.S. Patent Publication 2007/0261323. Each of these publications and patents, and every other patent, patent application, and publication cited in this patent application, is expressly and individually incorporated by reference herein in its entirety as part of this specification. Thus, in preferred embodiments of the present isolation system, the plurality of bearings of the “rolling ball” type including a plurality of identical upward-facing and downward facing opposed recessed bearing surfaces having, without limitation, a wholly or partially conical, spherical or parabolic shaped cross-sectional shapes and forming a cavity (preferably one having a region of constant slope) with a rigid ball-shaped bearing placed therebetween. The footplate comprising the upward facing recessed bearing surface rests or is preferably securely fixed to the ground or foundation, while the payload to be supported rests on or is joined to the top surface of the horizontal support panel, which in turn is joined to the frame comprising the isolation bearing halves comprising the downward facing recessed bearing surfaces. Rigid balls are contained in the cavities formed by opposing downward facing recessed bearing surfaces and upward facing recessed bearing surfaces. In this way, when external vibrations such as seismic movements occur causing the ground to move, the footplates are able to move relative to the upper bearing halves via the rolling of the rigid balls within the cavities defined by opposing opposing downward facing recessed bearing surfaces and upward facing recessed bearing surfaces. The inertia of the payload causes the payload supported by the present system to be thus isolated from the external vibrations. However, depending on the size of the seismic vibration, the bearings may have a limited range of mobility, and thus be able to absorb and dissipate a limited range of severity of seismic shock before becoming less effective. For example, the maximum amount of lateral displacement of the upper bearing halves and footplates relative to each other may be limited based on the size of the bearings or of the surrounding structure, building or room within which the present isolation system is contained. Also, in isolation bearings and platforms containing rolling balls, a severe shock such as that caused by a strong seismic tremor, could cause such severe lateral displacement of a rolling ball type isolation bearing that the ball is ejected from the bearing, causing failure and potential damage to the payload. There is a need for seismic isolation bearings that are stable (i.e., have a reduced tendency to fail), can withstand and absorb large seismic shocks, and which are easily integrated into the locations in which they are desired to be installed. There is also need for isolation bearing structures that have reduced susceptibility to resonance or harmonic interactions between bearings, spheres, and bearing surfaces during a vibration. Such interactions may be caused when bearing surfaces are substantially discontinuous (for example in which the load-bearing surface has radial grooves or crests) or when, for example, a central apex is too deep. In such structures, when the bearing is subject to a strong vibration, the spheres may “bounce” in and out of the apex, over or through the groove or ridge, or cause a shaking of the bearing when it interacts with other isolation bearings in, for example, an isolation platform. Isolation bearing stability may be improved by factors including increasing the size of the bearing surfaces, by increasing the depth of the recess on the bearing surface of one or more downward-facing bearing halves and upward-facing footplates, and/or by varying the shape of the bearing surfaces. Thus, in accordance with an embodiment of the present invention, the diameter of each of the upward-facing and downward-facing recessed bearing surfaces is between about 8 inches and about 36 inches or more. Preferably the diameter of the recessed bearing surfaces is about 8 inches, or about 12 inches, or about 15 inches, or about 20 inches, or about 24 inches, or about 30 inches or about 36 inches. The geometry of the load-bearing surface is of particular relevance when considering the forces acting upon the bearing during and after it is subjected to a vibration, such as a seismic vibration. As indicated elsewhere herein, generally, in accordance with various embodiments of the present invention, the bearings of the present invention may comprise recessed bearing surfaces having a combination of two or more different cross-sectional shapes, such as, without limitation, conical depressions, spherical depressions, and/or parabolic depressions. Within limiting the scope of the invention, in a preferred configuration the load-bearing surfaces of the dishes do not comprise ridges or groove-like depressions radiating substantially from the center of the dish or in any other direction, although there may be annular concentric regions of discontinuity between cross-sectional shapes. In one embodiment, the stability of the bearing, isolation system is also increased through the size of its “footprint” (its width versus its height) as compared to the center of gravity and weight distribution of the payload. Optionally, in certain embodiments flexible straps between and linking the upper bearing halves and lower footplates may be attached, thereby allowing lateral displacement between the bearing plates, but preventing their unwanted complete separation. In addition to, or instead of these straps, one or more isolation bearing restraint, for example those found in Moreno & Hubbard, U.S. patent application Ser. No. 12/567,548 (hereby incorporated by reference herein in its entirety) may also be used, thereby freely permitting lateral displacement of the bearing due to the rigid/rolling spheres between the bearing surfaces while simultaneously substantially preventing bearing failure due to unwanted separation of the bearing plates and/or ejection of the rigid balls from between the upper bearing halves and lower footplates. With respect to the upward-facing recessed bearing surface halves, in a further embodiment of the present invention, the seismic isolation system may comprise a rigid, second frame; this second frame may, but need not, be a mirror image of the rigid first frame; the bottom of the second frame is joined to a floor or foundation (for example, by bolts) and comprises a network of rigid criss-crossing elongate members wherein the second frame is joined on its upper side to each of the plurality of upward-facing recessed bearing surface halves, preferably at the intersection of the elongate members. While the upward-facing recessed bearing surface halves may be comprised in a footplate, in other embodiments of this general design the upward-facing recessed bearings may be substantially identical to the downward-facing recessed bearing surface halves. In another embodiment of the present invention, each of the footplates is placed in a recess in a floor or foundation and thereafter joined to the floor or foundation, for example with bolts. In a particularly useful embodiment, in the present system, each of the footplates is secured to a recess in the foundation in a manner causing the top surface of the horizontal flooring panel to be substantially level with and parallel to the foundation. The recess is adapted to include a gap or void between the isolation system and the foundation to permit and accommodate the necessary movement of the horizontal support panel, payload, first frame and downward-facing bearing halves in response to a seismic vibration of the foundation. Additionally, when the payload comprises equipment requiring electrical, computer, gas or other connections, flexible lines, hoses and/or conduit supplying such connections may be provided on the foundation side of the gap or from the ceiling ton the equipment; the flexible connection permits movement during a seismic tremor and the maintenance of the connection. In a particularly preferred embodiment, the gap or void may be used In particular embodiments of the isolation systems of the present invention the recessed bearing surfaces comprised within separate upper bearing halves and lower footplates are affixed to the bearing halves and footplates using any effective method suitable to withstand the stresses of a seismic event, such as using nuts and bolts, welding, or by any other sufficiently hardy method of affixing. The bearing halves and footplates themselves are comprised of a rigid material such as steel, a metal alloy, or a sufficiently rigid and strong polymer having a hardness to resist buckling, twisting and similar stresses expected to be encountered in a seismic event. Preferably, the bearing halves and footplates are made of ½ to ¼ inch steel. The bearing halves are in turn joined to the frame (and the footplates to any second, bottom frame comprising the upward-facing bearing surfaces or to the foundation, flooring or slab, respectively) using any suitable method, including but not limited to welding, bolts, cementing, embedding in concrete, and the like. The horizontal support panel is joined to the upper side of the frame using welding, bolts, ceneting, or similar suitable methods. The support panel may be a single construction or comprise a composite of a plurality of smaller panels used in combination to create the horizontal support panel that serves not only to support the payload but is also joined to the frame. The horizontal support panel(s) to be used in the isolation system of the present invention may comprise any appropriate material (including metal, fiberglass, plastic, plywood, wood or composite materials, or any combination of such materials). The support panel itself may comprise, for example, a plurality of reinforced geometrical panels, such as quadrilateral panels, or panels of regular shape that are substantially interchangeable; for example, rectangular panels of a standard size. In certain embodiments a particularly advantageous size is a 2 foot square panel. In a typical embodiment, these panels or groups thereof are supported (for example, supported at least at each corner) on their bottom side by the rigid frame in a grid- or matrix-like arrangement. While in most (and all preferred) embodiments the isolation systems of the present invention do not comprise raised access isolation floors, in some, less preferred embodiments cases certain panels may be modified to comprise access apertures through which, for example, cables, hoses, wires, network connections, conduit, and/or other materials may be fed for connection with the payload objects. In addition, the support panel and/or frame are often useful in permitting lines, such as electrical, heating, cooling and/or data lines, to be distributed within a room or workspace without the need for such lines intruding on support panel itself. In a presently preferred embodiment of the invention, the horizontal support panel is first stably supported by a frame made of material sufficiently strong to support the weight of the objects to be placed upon the flooring. Examples of useful framing material include, without limitation, steel, aluminum, titanium, iron, bronze, polymeric materials, alloys of these materials and the like. Preferably, the material is sufficiently lightweight to permit facile assembly and disassembly of the frame in situ, and to keep the overall load upon the bearings to a minimum. In preferred embodiments frame members may comprise steel or other alloys in the form of girders or I-beams. The frame may be constructed using frame members arranged in any manner (often in a reinforcing polygonal arrangement) giving the frame sufficient structural support to adequately support the objects to be placed on it and to resist buckling during a seismic event. Since most locations into which the present system is installed are likely to be rectangular, the frame members may commonly be arranged in a generally quadrilateral manner, such as the framing shown in FIG. 5 of this specification. However, other arrangements are possible including frame members arranged in triangular fashion, either in planar or tetrahedral fashion, or in other geometrical shapes that lend the frame its strength. In yet other embodiments, the frame may comprise the foundation of a structure, such as a shipping container, mobile home, or a structure made in a similar manner as a mobile home. The rigid ball(s) to be used in the isolation bearing cavity is preferably a rigid, uncoated hardened steel ball bearing, although rubber or elastomer-coated balls, synthetic balls and the like may be exclusively utilized, for example to provide a measure of dampening, in less preferred embodiments. Additionally, a combination of uncoated, low friction balls may be used in combination with a number of coated, higher friction rigid balls, with the latter ball type acting as a damper to absorb energy by friction and the mix of coated and rigid balls tailored to the specific payload mass and situation. The ball may comprise stainless steel, or any hard metal, metal alloy, or (in the case of damping balls), hardened polymeric material that is able to support a weight of at least about 1000 lb without substantial deformation, or any deformation. Additionally, the isolation system of the present invention comprises a plurality of bearing halves and footplates, preferably sufficient to stably support the flooring without substantial movement except in the event of a seismic vibration. For a quadrilateral floor, this generally means at least one such bearing half (with a corresponding footplate to pair with) will be typically placed at or near each of the four corners of the rigid frame (or flooring if the floor is independently reinforced. Also additional bearing halves may be placed in other locations in a manner preventing the frame from sagging or buckling, with due account being taken for the load tolerance of each individual bearing (e.g., 1000 lbs or more) and the total foundation or pad load and distribution thereof, when calculating the total number and distribution of bearings to be utilized. The bearing halves may make up a matrix of paired bearing halves and footplates across the floor or foundation of the isolation system. The present invention also encompasses methods for isolating an industrial payload from a seismic vibration comprising placing or assembling a payload on, or joining a payload to, a seismic isolation system described herein. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a drawing showing the force vectors upon a rolling rigid ball on an inclined plane. FIG. 2 is a top view of an embodiment of a recessed bearing surface of a footplate having a composite bearing surface, as described in an embodiment of the present invention. FIG. 3 is a side view of the recessed bearing surface shown in FIG. 2 , of the edge of the recessed bearing surface of a footplate as described in an embodiment of the present invention having a composite bearing surface. FIG. 4 is a top view of a footplate in accordance with an embodiment of the present invention having a composite bearing surface and a circular rim. FIG. 5 is a top view of an embodiment of a portion of the isolation system showing an assembly showing four bearing halves each joined to the bottom surface of a portion of a rigid frame. FIG. 6 is a perspective top view during assembly of an embodiment of a seismic isolation system in accordance with the present invention prior to the horizontal support panel being installed. FIG. 7 is a perspective top view of the seismic isolation system shown in FIG. 6 wherein the horizontal support panel has been partially installed. FIG. 8 is a partial side view of an isolation bearing comprising a bearing half, footplate and portion of the frame and support plate in accordance with the embodiment in FIG. 6 . FIG. 9 is a cross-sectional view of a resting position of an isolation bearing comprising bearing half footplate, rigid ball, frame and support panel in accordance with an embodiment of the invention with the rigid ball disposed in the cavity between the corresponding downward-facing and upward-facing recessed bearing surfaces. FIG. 10 is a cross-sectional view of an isolation bearing in accordance with an embodiment of the invention showing a bearing half and a footplate with the rigid ball disposed in the cavity between the corresponding downward-facing and upward-facing recessed bearing surfaces, when the bearing half has been displaced to the maximum extent with respect to the upward-facing bearing surface of the footplate. FIG. 11 is a top view of a plan for isolating a syringe line apparatus using a rolling ball-type isolation bearing according to another embodiment of the seismic isolation system of the present invention. FIG. 12 is a top view of a plan for isolating a vial processing apparatus using a rolling ball-type isolation bearing according to another embodiment of the seismic isolation system of the present invention. FIG. 13 is a view of a partially prefabricated external structure for containing a payload. FIG. 14 is a view of a segment of a prefabricated structure for containing a payload, comprising air conditioning equipment. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS In one embodiment of the isolation system of the present invention, FIG. 1 is described below with reference to a ball-and-cone type rolling ball bearing. The ball-in-cone bearing may be used as an initial (and non-limiting) illustration of the relation of geometry and the physical principles at play in rolling rigid ball isolation bearings. The ball rests between the upper/downward-facing and lower/upward-facing recessed bearing surfaces, and in certain cases may rest in central apices or depressions of one or both such bearing surface. Upon the application of a lateral force, there may be desired some initial resistance to displacement of the ball from these depressions. The resistance may be made sufficient to prevent any substantial displacement of the two bearing surfaces with respect to each other if the applied lateral force is too small. Thus, where present, the spherical shape of the central apices provides an initial restoring force urging the ball to remain within the central apex. This restoring force is identical regardless of the direction from which the lateral force is applied. Regardless whether the bearing possesses central apices or not, if the initial lateral force is great enough, the bearing halves and footplates of the bearing will be moved relative to one another by the applied force through the action of the rigid/rolling ball. This means that the applied lateral force is strong enough to force the ball along the preferably at least partially conical recessed surface. This requires that either the upper/downward-facing recessed bearing surface or the ball (or both) move “uphill” against both the force of gravity and the mass of the load placed on the upper bearing halves of the claimed seismic isolation system. Therefore, the lateral force is temporarily partially stored as vertical “potential energy”. If the bearing surface is at least partially conical, the cross-sectional view of the bearing surface will have at least a portion that is linear. Once the ball is located on linear portion of the second/upward-facing recessed bearing surface, the physics are similar to an object placed on an inclined plane, since in a ball-in-cone bearing the second/upward-facing recessed bearing surface has at least a region of constant slope. For simplicity, FIG. 1 examines primarily the lower recessed surface and the ball, with the understanding that similar principles apply (although in mirror image) to the upper recessed surface, which “floats” upon and is supported by the rolling ball. Thus, with reference to FIG. 1 , Fg equals mg, where m is the combined mass of the ball and the load transferred upon the ball by the upper plate, and g is gravitational acceleration (9.81 m/s 2 ). Although Fg is exerted downwards, on the inclined plane, Fg is comprised of two vectors: FN (the normal force extending perpendicular to the surface of the plane) and Fp. Due to the shape of the ball, the force opposing Fp (Ff; the frictional force) is minimal and therefore disregarded in this diagram. The magnitude of each of the vectors Fp and FN is dictated by the angle of the inclined slope and the magnitude of Fg, and can be calculated geometrically from the Pythagorean theorem, where Fg 2 =FN 2 +Fp 2 . Thus, Fp is a constant, so long as the angle between the recessed surface and the horizon is also constant. Therefore, once the lateral motion has caused the ball to displace onto either or both the upper or lower recessed bearing surface, Fp, the “restoring force” is constant because of the conical nature of the ball-in-cone surface. With this explanation, it can now be seen that if the bearing surface has a region of a different cross-sectional shape (e.g., a shape of a spherical curve) such that vertical displacement as a function of lateral displacement is not constant, the magnitude of the restoring force Fp as a function of lateral distance traveled by the rolling ball in this region is also not constant. For example, if one imagines for a moment that the cross-section of the bearing surface, or a region thereof, is a spherical curve rather than conical. In such a bearing surface a radius through the center of the bearing surface to the perimeter of the bearing surface viewed in cross-section would yield a non-constant, curved slope. Thus, a restoring force Fp is not be constant if the cross-section of the recessed surface is any other shape than a straight line (meaning that the shape of the bearing surface is at least partially conical). Rather, the restoring force (and vertical distance traveled by the ball) would increase as a function of the distance the ball travels from the center of the bearing (i.e., toward the perimeter of the bearing surface, where the steepness of the slope of the curve increases). In a spherical curve, the rate of change of the restoring force is constant, but not the restoring force itself. Thus, with each unit of lateral distance traveled from the center of the bearing surface, the greater the vertical distance traveled and the greater the restoring force. Other simple planar open curves (such as various parabolic or other concave curves) have the same basic character as the spherical curve, so that as the ball moves from the center of the bearing towards the perimeter of the bearing surface the change in vertical displacement as a function of lateral distance traveled increases at different non-constant rates depending upon the shape of the curve. In the present invention it has been surprisingly found that an optimal configuration for the recessed load-bearing surface of a rigid/rolling ball isolation bearing, particularly when the isolation bearing is subjected to a strenuous vibration and is used in conjunction with other isolation bearings (such as in an isolation platform, track, or floor), is a combination of more than one shape. In a preferred embodiment, when viewed in cross-section, at least one (and preferably both) of the upper and lower load-bearing surface has an enlarged concave indentation at the center, with a border around the perimeter of the bearing comprising a region of constant slope, as in a conical bearing. In another preferred embodiment, the present inventors have discovered that a rigid rolling ball isolation bearing tends to perform more robustly, and will be subject to less disruptive harmonic resonance, if either or both recessed load-bearing surfaces lack a central spherical depression having approximate diameter of the rolling ball, or have a very shallow depression in the center. Preferably the shapes of the curve and angle of the cross-section of each load-bearing recessed bearing surface or “dish” are such that regardless of the input shear acceleration caused by the seismic event, the output is limited to a maximum acceleration. For example, in one embodiment of the invention, the output acceleration may be limited by the combined curve and angle of the dish to about 0.1 g or less, even when the input shear is about 0.3 g, or about 0.35 g, or about 0.4 g, about 0.5 g, or about 0.6 g, or about 0.7 g, or about 0.8 g, or about 0.9 g, or about 1.0 g or more. In another embodiment the output acceleration may be limited by the combined curve and angle of the dish to about 0.8 g or less, even when the input shear is about 0.3 g, or about 0.35 g, or about 0.4 g, about 0.5 g, or about 0.6 g, or about 0.7 g, or about 0.8 g, or about 0.9 g, or about 1.0 g or more. In another embodiment the output acceleration may be limited by the combined curve and angle of the dish to about 0.75 g or less, even when the input shear is about 0.3 g, or about 0.35 g, or about 0.4 g, about 0.5 g, or about 0.6 g, or about 0.7 g, or about 0.8 g, or about 0.9 g, or about 1.0 g or more. The attenuation of the input shear forces are a function of the base shear input. Thus, the percentage attenuation can be up to about 66%, or up to about 71%, or up to about 75%, or up to about 80%, or up to about 83%, or up to about 86%, or up to about 88%, or up to about 90% or more. It will be understood that the ranges of input shear, output shear and percentage attenuation presented above specifically disclose, and are intended to specifically disclose, all points between any two maximum and minimum values listed and any range from a value greater than 0 and up to any such maximum value listed. Preferably, although not necessarily, the upper/downward-facing recessed bearing surfaces in the bearing halves and/lower/upward-facing recessed bearing surfaces in the corresponding footplates are substantially alike, or identical, in their opposing surfaces. In such seismic isolation systems, or bearings or platforms the upper bearing half supports the one or more loads, and the footplate directly or indirectly contacts the floor, foundation, surface or area below the bearing or platform. Between each bearing comprising upper and lower recessed bearing surfaces, at least one rigid, spherical rolling ball is placed within the cavity formed from opposing, recessed composite bearing surfaces, thereby allowing the upper bearing half and lower footplates to displace relative to one another by rolling on the balls. As lateral forces (e.g., in the form of seismic vibrations) are applied to the bearings, the upper bearing halves are displaced laterally with respect to the lower footplates, such that the rigid balls therebetween roll and rotate freely in any direction and, if sufficiently hard and rigid and lacking in dampening, in an almost frictionless manner about their respective depressions or cavities. The ball or balls permit the bearing to store the energy of the vibration as potential energy by being raised to higher elevations along the bearing surface, such that, the ball(s) remain in contact with the upper and lower bearing surfaces and the upper and lower bearing surfaces thus remain indirectly in contact with each other. Due at least in part to the conical, spherical, parabolic, or other raised shapes of the first and second composite bearing surfaces, the gravitational forces acting on the payload or structure, and the structure's mass, produce a lateral force component tending to restore the seismic isolation system, isolation bearing or platform to its original central position, with the upper bearing halves being positioned substantially directly above the lower footplates. FIG. 2 shows a preferred composite bearing surface used in an embodiment of the footplate of the seismic isolation system of the present invention. In this figure, the load-bearing portion of each footplate of the plurality of footplates/dishes (only a single footplate is shown) comprises, in a top view, a substantially circular load-bearing recessed surface having a concentric central region 101 comprising a curved cross-sectional region, such as a spherical curve, and an annular region 103 ringing the central region and comprising a flat, sloped surface linking the central region 101 with a raised lip 105 at the perimeter of the circular load bearing region. Preferably, the central region 101 does not comprise a central dimple for the rigid ball to rest within when the footplate bearing is not subject to shear forces. However, in other embodiments the footplate bearing surface may contain a central dimple for the rigid ball to rest within when each of the plurality of footplate bearings are at rest. Still with reference to FIG. 2 , in a preferred embodiment, the ratio, in a line segment extending from point a to point a′, of the diameter of the central region 101 to the remainder of the load-bearing surface (the annular region 103 and lip region 105 ), is about 2 to 1. Thus, in a preferred embodiment where the dish is between about 8 inches to about 48 inches in total diameter, a dish having this ratio has a central region diameter of about 5.3 inches to about 32 inches, with the annular region (which is passed through twice by the line segment) having a width of about 1.3 to about 8 inches. The majority of this annular region (about 1.625 inches to about 6.5 inches) is the flat, sloped surface, with the raised lip comprising about 0.375 inches to 1.5 inches of the 1.3 inch to 8 inch annular region. FIG. 3 shows the perimeter portion of the sameembodiment of the composite-shaped bearing surface of the footplate component of the present isolation system invention shown in FIG. 2 , but this time in cross-section. In one example of a footplate, as shown, the border 107 between the central, spherically curved region 101 and the flat, linear-sloped annular region 103 is shown, with an approximately 1.6 inch length of this latter flat region, rising 0.25 inches with a constant slope equaling about 0.25/1.6 or about 0.156. The border 109 between the substantially flat, sloped annular region 103 of the footplate/dish and the lip 105 is shown, with the lip rising in a substantially constant slope. In this embodiment, the slope is: approximately 0.25 inches of vertical rise in approximately 0.125 inches of horizontal length, or approximately 2:1. The lip becomes horizontal for about 0.25 inches before reaching the edge of the plate. In this case, the central, spherically curved region 101 has a radius of curvature of about 86 inches, meaning it corresponds to an arc of a circle having a radius of about 86 inches. Those of ordinary skill in the art will immediately recognize based on the foregoing, that the embodiment described above is only one of various possible embodiments of composite bearing surfaces that may be used in the present invention. In particular, the exact curvature of the central, spherically curved region 101 may be varied (for example, to a parabolic shape) without departing from the spirit of the invention. It will be recognized, based on this disclosure, that the design of the composition bearing surface depicted in FIG. 2 and FIG. 3 may serve to provide somewhat greater restoring forces in less violent earthquakes or vibrations. Additionally, the total horizontal displacement will be less than would otherwise be the case with solely a conical load-bearing surface in stronger earthquakes. Where the vibration is strong enough to cause the rolling ball to cross border 107 , then the restorative force does not continue to increase as the rigid ball travels up the flat, sloped annular region 103 , thereby helping to prevent excessive rocking of the bearing (or the payload placed upon the bearing) when the upper bearing half seeks to return to equilibrium after the vibration has subsided. In certain embodiments, the lack of a small central spherically curved dimple or recess also contributes to a more smoothly operating isolation bearing during a strong vibration. Without such a recess the bearing is less likely to fail or be damaged as the bearing moves back and forth due to a pendulum-like swing of the bearing as it restores its originals position. Preferably, although not necessarily, the substantially directly opposing upper and lower recessed bearing surfaces have substantially identical load-bearing surfaces comprising composite curved and flat angled cross-sectional indentations, preferably substantially as described above. Although the isolation bearing in FIGS. 2 and 3 are shown as having a single pair of first and second recessed bearing surfaces, it is to be understood there are a plurality of bearings comprising such bearing surface pairs with at least one rolling rigid ball disposed between each of the pairs, as is described further, in the seismic isolation systems of the present invention. FIG. 4 shows a preferred embodiment of a footplate 111 having a composite bearing surface substantially as in the embodiment shown in FIG. 2 and FIG. 3 used in an isolation system of the present invention. This figure shows the flat plate region 113 of the foot plate 111 that is joined to the floor, foundation, or pad. In one embodiment, the footplate may be fitted into a recess in the floor, foundation or base and then secured to the floor or foundation, or secured directly to the floor or foundation, such as with bolts, cement, etc. Shown in FIG. 5 is a view of a partially assembled embodiment of the present invention comprising a partially constructed frame 123 with four isolation bearing halves 121 (only two are visible in FIG. 5 ) joined to the bottom surface of a portion of the frame 123 . The placement of the bearings is substantially symmetrical about the intersections 125 (see FIG. 9 ) of the elongate member components 127 that are part of an extendable network of elongate members adapted to accommodate varying sizes or configurations of payloads to be isolated from seismic vibrations. The frame of this portion embodiment of the isolation system is to be coupled with four footplates 111 to be disposed such that the upper/downward facing bearing surfaces 117 ′ of the bearing halves substantially directly oppose the lower/upward facing bearing surfaces 117 of each of the four footplates 111 . When assembled, four rigid balls 115 , are each disposed in the cavities between a respective downward-facing and upward-facing recessed bearing surface of an assembled isolation bearing to form a portion of an embodiment of a seismic isolation system of the present invention. The bearing halves 121 , just as the footplates, have circular rims substantially identical to those shown in 119 . Using a plurality of footplates 111 and isolation bearing halves 121 fitted on a rigid frame 123 comprising elongate members 127 along with rigid balls 115 disposed in the cavities of corresponding composite recessed bearing surface pairs 117 and 117 ′ assembled as described above, various apparatus, such as seismic isolation systems, isolation platforms, isolation floors and the like can be fabricated. Shown in FIG. 6 is a perspective top view of an embodiment of a partially assembled, extendable seismic isolation system 129 in accordance with the present invention wherein a horizontal support panel has not yet been installed. Note that in this embodiment of the invention, the footplates are joined to the foundation or slab substantially at the level of the surrounding foundation; i.e., without a recess in the foundation or slab. When configured in this way no gap in the foundation is required in order for the support panel of the isolation system to move in reaction to a seismic tremor. However ample space for such movement must be provided around the support panel. In other embodiments the footplates are secured to the foundation or slab within a recess permitting the support panel to be at the same level as the surrounding foundation; the recess also defines a gap between the isolation system and the Shown in FIG. 7 is a perspective top view of a fully assembled version 131 of the seismic isolation system 129 shown in FIG. 6 wherein the horizontal support panel 133 has partially been installed. Thus, taken together, FIGS. 6 and 7 together depict an embodiment of an isolation system 131 in accordance with the present invention comprising: a) a horizontal support panel 133 having a top surface 135 and a bottom surface 137 (not shown here, but shown in FIG. 9 ), wherein the horizontal support panel 133 is structured to support a payload of appropriate weight on the top surface 135 ; b) a rigid first frame 123 adapted to support the support panel 133 , wherein said first frame 123 is joined to the bottom surface 137 of the support panel; c) a plurality of isolation bearing halves 121 wherein each bearing half is directly connected to the bottom side of said first frame 123 and each bearing half comprises a downward-facing recessed bearing surface 117 ′; d) a plurality of seismic isolation footplates 111 , each footplate comprising a upward-facing recessed bearing surface 117 and wherein each of said footplates 111 is directly joined to a flooring, slab or foundation 139 wherein, in this case, the upward-facing recessed bearing surface 117 of each of said footplates 111 is a mirror image of and opposes a downward-facing recessed bearing surface 117 ′ of a corresponding seismic bearing half 121 disposed substantially directly opposite the footplate, thereby defining a cavity therebetween; e) a plurality of rigid balls 115 located in each of such cavities and structured to be sufficiently hard to support the payload in combination; wherein, in the event of a seismic vibration causing the footplates 111 to move, the inertia of the payload, the support panel 133 , the first frame 123 and the bearing halves 121 causes the rigid balls 115 in the cavities therebetween to roll upwards from the corresponding said upward-facing recessed bearing surfaces 117 , thereby cushioning the payload from the full force of said seismic vibration. FIG. 8 is a partial side view of an isolation bearing comprising a bearing half 121 , footplate 111 and portion of the frame 123 and support plate, in accordance with the embodiment in FIG. 6 . This figure shows that once the rigid ball 115 is disposed in the cavity formed by the recessed bearing surfaces 117 and 117 ′ (not shown), the circular rims 119 and 119 ′ defining the bearing half 121 and footplate 111 do not contact each other and define a gap 140 to lessen the possibility of friction between bearings causing bearing failure during use. FIG. 9 is a cross-sectional in situ view of a portion of an isolation system at equilibrium according to the present invention comprising an isolation bearing comprising a bearing half 121 and footplate 111 consistent with the embodiment shown in FIGS. 6-8 . The rigid ball 115 is disposed in the cavity defined between the corresponding upper and lower recessed bearing surfaces 117 and 117 ′. Shown in FIG. 9 is a cross-sectional view of the horizontal support panel 133 having a top surface 135 structured to support a payload to be isolated from a seismic vibration and a bottom surface 137 that is joined to a rigid frame 123 . In this and other preferred embodiments the support panel is joined to the frame substantially symmetrically about the intersections 125 (not shown here, but shown in FIGS. 6 and 9 ) of the elongate member components 127 that are part of the reinforced network of elongate members to accommodate the payload to be isolated from seismic vibrations. Also shown in FIG. 9 is a welded connection 141 to secure component rigid elongate members 127 of the frame 123 . Also shown are bolts 143 and welds 145 used to join bearing half 121 to the frame 123 . The downward facing rigid bearing surface 117 ′ bearing element of bearing half 121 is also shown in this figure as being supported by a plate element 147 and weld 149 at the bottom side of the bearing surface 117 ′. The bearing surface 117 is similarly supported at its bottom surface/side by weld 151 to footplate 111 . Various alternative means and methods of joining the rigid frame 123 and support panel 133 , such as bolts, etc., (such as 153 ) can be used. Those of ordinary skill in the art will understand that various effective ways exist of securing components such as bearing halves, support panels, elongated members or girders; these including, without limitation, bolting, welding, one-piece casting, cementing or gluing, and the like. From FIG. 9 , it can be seen that the bearing half 121 has a circular rim 119 ′ extending vertically at the edge of, and substantially perpendicular to, the bearing surface 117 ′ and from the bottom of the bearing half 121 , just as the footplate 111 has a circular rim 119 extending vertically from the bottom of, and substantially perpendicular to, the footplate along the edge of bearing surface 117 . FIG. 10 is a cross-sectional view of an isolation bearing comprising bearing half 121 and footplate 111 in accordance with the embodiment in FIGS. 6-9 ; the rigid ball 115 is disposed in the cavity between the corresponding first and second recessed bearing surfaces 117 ′ and 117 , and the bearing is in a displaced position. In this figure, the rigid ball 115 has rolled within the cavity formed by the upward-facing recessed bearing surface 117 in the footplate 111 and corresponding downward-facing recessed bearing surface 117 ′ of the isolation bearing half 121 , and is positioned in contact with rims 119 and 119 ′. The dotted lines show the position of the (upper) bearing half in the rest position. FIG. 11 is a schematic diagram comprising top view of an embodiment of a complete industrial seismic isolation system. In this case the payload is a product processing syringe line apparatus isolated using a composite surface rolling ball type isolation bearing system. In this embodiment, the horizontal support panel comprises a plurality of individual panels (which may comprise layered, laminated, or solid panels) that are bolted together, and shown here is bolted panel joint 157 . Also, in this embodiment, the isolation system 155 , is secured via the component footplates 111 , in a recess in the foundation in a manner causing the top surface 135 of the horizontal support panel to be substantially level with the foundation, the recess being adapted to include a gap or void between the isolation system and foundation to accommodate an isolating movement of the horizontal support panel, the payload (for example, a syringe line), first frame 123 and bearing halves 121 in response to a seismic vibration within the gap or void and, to permit installation of flexible lines of supply to the payload within the gap or void. Thus, the outer edge 159 of the isolation system 155 , or shown here as the edge of the top surface of the horizontal support panel 133 of the isolation system and the outer edge 161 of the recess in the foundation upon which the isolation system rests define a gap 163 between the isolation system and the foundation. FIG. 12 is a top view of another seismic isolation system for isolating a payload consisting of a vial filling line using a ball and cone type isolation bearing. In yet another embodiment of the present invention, the seismic isolation system of the present invention is adapted and structured for placement on a cement or concrete pad or slab, preferably on the outside of a structure. In certain cases computer servers and/or other payloads are desired to be placed outside main buildings and to be contained within a weather-resistant shed particularly made or acquired to house such payloads. Such outside placement permits more facile addition and modification of payloads, since the payloads (and in certain cases the structures or “outbuildings” that house them) can be transported by truck and easily moved into place to be supported by the claimed seismic isolation system. Moreover, an array of pads or “pad farm” may be easily created to add new storage space for computers, hazardous chemicals, chemical waste, and the like as desired. The slab is generally from about 6 inches to about 1 foot in thickness; specific variations in this thickness may be indicated from location to location according with local building code requirements. The upward-facing bearing surfaces may be contained in footplates that are joined to the pad; they may be embedded in the pad or joined using bolts or other securing joining means. The pad is usually reinforced using materials such as steel rods or rebar to prevent cracking. In this embodiment of the invention, the upper, downward-facing bearing surfaces of the isolation bearing halves are joined to a first frame or support panel that either comprises, or is itself joined to a second frame or support panel that comprises, a structural floor component of a housing such as a shipping container, a mobile home or prefabricated “outbuilding” or the like, within which the payload is protected from direct sunlight, rain, snow, and the like. The housing, which is generally relatively lightweight, may contain an air conditioning and/or heating unit to maintain a substantially constant temperature for the payload within the housing. In presently preferred embodiments the housing comprises more than one prefabricated subunit, which can be quickly assembled in situ. FIG. 13 shows an embodiment of such a housing under construction; FIG. 14 shows a temperature control subunit of such a housing containing air conditioning equipment; a similar temperature control subunit can be seen in FIG. 13 at the far side of the housing. These figures also illustrate that the bottom frame or plate of the housing comprises a series of open, approximately tubular structures structured to fit the tines of a forklift to facilitate movement of housing subunits into position for assembly, and for final assembly of the seismic support structure. The downward-facing bearing halves are secured joined to the bottom frame or plate of the housing, preferably, although not invariably, at each of the four corners of the structure; additional bearing halves may be added as necessary. As in other embodiments, the bearing halves are joined to the bottom frame or plate of the housing securely; preferably using bolts or welding. In this and every aspect of the invention disclosed and claimed herein it is preferred that the upward-facing and downward-facing bearing surfaces are identical, so as to provide parallel opposing slopes for the rolling ball during a tremor. If this is not the case the force exerted at the top and the bottom is not the same, and sliding of the rolling ball is more likely, which will result in uneven offsets. This is particularly true when in addition to the slope being on the bottom, the dissipative element (such as damping) is only on the bottom. Although FIGS. 13 and 14 show a housing in which the bottom frame or plate of the housing is made of metal, in other cases the frame or plate of the housing may partly or wholly comprise a wood, a polymeric alloy (such as a thermoplastic), a carbon fiber structure, a fiberglass structure, or a combination of two or more of all of these. It is preferred that the payload within such housing be secured firmly within the housing to prevent payload toppling in the housing or through the walls of the housing. Although the foregoing invention has been described in detail for purposes of clarity of understanding, it will be obvious that certain modifications may be practiced within the scope of the appended claims. Additionally, features illustrated herein as being present in a particular embodiment are intended, in aspects of the present invention, to be combinable with features not otherwise illustrated in this patent application as being present in that particular embodiment. All publications and patent documents cited herein are hereby incorporated by reference in their entirety for all purposes to the same extent as if each were so individually denoted.	Improved isolation flooring systems, and methods for their use are disclose for protecting a payload, such as heavy or delicate equipment (such as laboratory or computer equipment), from damage due to vibrations, such as seismic vibrations. In preferred embodiments, the invention is drawn to methods of isolating heavy and/or sensitive objects from the full acceleration of seismic vibrations.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present invention is a continuation application of U.S. patent application Ser. No. 13/599,567 of Robert H. KOERNER, entitled “DRAINAGE MANAGEMENT SYSTEM AND METHOD,” filed on Aug. 30, 2012, now allowed, which claims benefit of priority to U.S. Provisional Patent Application Ser. No. 61/530,953 of Robert H. KOERNER, entitled “DRAINAGE MANAGEMENT SYSTEM AND METHOD,” filed on Sep. 3, 2011, the entire disclosure of which is hereby incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention generally relates to systems and methods for drainage management, and can include a drain management system employing a weighted object devised for the purpose of positioning and holding down trough structures used for the conveyance of liquids, such as storm water drainage, irrigation distribution, a diversionary device when positioned in rotated positions, and the like [0004] 2. Discussion of the Background [0005] In recent years, solutions to combat erosion and drainage typically employ closed piping, prefabricated continual or cast in place concrete lining systems of various shapes and configurations, construction of liners made from materials, such as stones or graded aggregates. However, such drainage management systems and methods typically are not cost effective, are not reusable, and lack ease of maintenance. Therefore, there is a need for a method and system for drainage management that addresses the above and other problems with current methods and systems. SUMMARY OF THE INVENTION [0006] The above and other problems are addressed by exemplary embodiments of the present invention, which advantageously provide drainage management systems and methods that relate to the inexpensive lining of an open liquid conveyance system and/or diversion of fluids. The drainage management systems and methods of the present invention can be used to hold down an open conveyance system, and not necessarily a closed system. [0007] Accordingly, aspects of the present invention relate to a system and method for drainage management, including a pipe that is cut along a longitudinal section thereof; and a pipe block having a curved section corresponding to a diameter of the cut pipe and including supporting legs. The curved section of the pipe block is configured to support the cut pipe. [0008] The system and method can include an under pipe barrier section located along the drainage management system and configured for stopping flowing water on an outside of the drainage management system for erosion control. [0009] The system and method can include an end pipe barrier section located at an end the drainage management system and configured for disallowing water passage to an outside of the drainage management system to avoid erosion. [0010] The system and method can include an end barrier closing block section located within the end pipe barrier section and configured for closing off an end of the drainage management system. [0011] Still other aspects, features, and advantages of the present invention are readily apparent from the following detailed description, simply by illustrating a number of illustrative embodiments and implementations, including the best mode contemplated for carrying out the present invention. The present invention is also capable of other and different embodiments, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. BRIEF DESCRIPTION OF THE DRAWINGS [0012] The embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which: [0013] FIGS. 1-8 are used to describe drainage management systems and methods, according to the present invention. DETAILED DESCRIPTION OF THE INVENTION [0014] The present invention generally relates to systems and methods for drainage management, and can include a drain management system employing a weighted object devised for the purpose of positioning and holding down trough structures used for the conveyance of liquids, such as storm water drainage, irrigation distribution, a diversionary device when positioned in rotated positions, and the like. Advantageously, the drain management system can be used for the construction of an open drainage way by use of inexpensive and readily available and various sized circular plastic or other suitable material pipes of length cut into determined partial circles longitudinally and positioned and held down by weighted objects specifically formed and shaped for the mechanical purposes necessary to perform the intended use. Of equal value is the effect to environmental issues of erosion, sedimentation, enhancing water quality as well as a means of controlling pollution issues, and the like. [0015] The earth is subject to natural and manmade flow of water that obeys the laws of gravity and in the process has developed water courses through all forms of materials. Civilization in developed locations improve on collecting and directing water flows of different sources (e.g., mostly rain) to allow a controlled system to aid in society living a never ending improvement on living conditions for health and welfare. Most collection and conveyance systems end into open area referred to commonly as ditches or waterways, natural and manmade. These areas left unattended in the majority of situations create erosion in quantities and rates depending on the soils the water comes into contact. [0016] Solutions to erosion are closed piping, prefabricated continual or cast in place concrete lining systems of various shapes and configurations, construction of liners made from materials, such as stones or graded aggregates. By contrast, the drainage management systems and methods of the present invention provide for cost effectiveness, reusability, and ease of maintenance, and can be used to stop or prevent erosion, while at the same time controlling water flow energy, removing sedimentation from flowing water, and the like. [0017] To counteract erosion that is considered destructive to the health and welfare of the people in many forms, laws as well as common sense approaches are applied to the drainage systems to prevent erosion. An example of a devised system is the Smart Ditch System (see, e.g., the World Wide Web at smartditchsystem.com). Such a system is a specifically manufactured plastic conveyance system that is positioned and held down with mechanical anchor devices made specifically for the system. However, what is not accomplished by such a system is use of materials already commonly available worldwide, nor does the system allow for simple and fast installation, nor the ability to allow replacement or relocating of the system without any problem or loss of the original value. [0018] Therefore, there is a need for a method and system for drainage management that addresses the above and other problems with current methods and systems. The above and other needs are addressed by embodiments of the present invention, which provide drainage management systems and methods of the present invention that need not replicate mat type systems of any suitable type for bank type erosion from running water or wave/tidal action of moving water. In addition, the drainage management systems and methods of the present invention need not be employed for holding down items in water, such as pipelines or cables of any suitable type. Rather, the drainage management systems and methods of the present invention relate to the inexpensive lining of an open liquid conveyance system and/or diversion of fluids. The drainage management systems and methods of the present invention can be used to hold down an open conveyance system, and not necessarily a closed system. [0019] Accordingly, in illustrative aspects, there are provided systems, and methods for drainage management including at least one of a cut pipe as shown or described in FIG. 3 ; and a pipe block as shown or described in FIG. 1 , 2 or 4 . The systems and methods further comprising an under pipe barrier section as shown or described in FIG. 5 , an end pipe barrier section as shown or described in FIG. 6 , and an end barrier closing block section as shown or described in FIG. 7 . [0020] Advantageously, the drainage management systems and methods of the present invention can employ use of common materials in a manner to lower required expertise, lower investments for production, lower material costs, lower material shipping costs, lower installation costs, lower level of preciseness needed for installation, lower maintenance costs, lower replacement costs, create a 100% recyclable green product, stop or prevent soil erosion, stop or prevent bank sloughing, create sedimentation pooling, oxygenate water by turbulence, reduce water flow energy by turbulence, and the like. [0021] In FIGS. 1-8 , a pipe ditch liner 200 (e.g., made of plastic or any other suitable material, etc.) shown in FIG. 3 , can be a commonly manufactured solid, ribbed, or rib lined plastic or other material drainage pipe in any suitable diameter of various lengths and that are cut in half, in third, or any suitable lesser radian of a circle of the pipe, etc., as needed, longitudinally as shown with cut lines 201 to provide a liquid flow area of approximately one half, one third, or any suitable lesser radian of the circle of the pipe, etc., being used. Such cut pipe can be performed at and obtained from the pipe factory, which then allows lower shipping costs due to the bulk dimension of a pipe being reduced due to use of space not determined by the full circumference of the pipe. Existing manufactured pipes 200 can also, with minimal time and tools, be cut at the installation site, if necessary. [0022] Jointing of continuous pieces can be performed as the pipe is manufactured with an “over under” lapping as an industry standard shown at 202 and commonly known as “bell and spigot” or “male and female connector” (e.g., manufactured or easily cut in the field for custom lengths of pipe). Existing systems of “sealing the joint” as shown at 202 can be performed at the user's discretion for the effectiveness of the seal at the joint 202 . [0023] Placement of such a piping segment 200 allows for liberal line/grade or bedding conditions. The half pipe 200 stops the bottom erosion of soils keeping the water from saturating earth on the bottom or sides of a natural or constructed soil system. The pipe 200 can be held in place by pipe blocks of FIGS. 1-2 and stops the bottom side slopes from sloughing into the flow area due to the solid side wall structure of the pipe 200 to counteract tangential forces. The pipe 200 holds back the side walls and is kept in shape and from moving by the forces induced by the pipe blocks of FIGS. 1-2 . [0024] In FIGS. 1-2 , concrete blocks or pipe blocks 100 can be suitably shaped and for example, made of reinforced concrete, and the like. The material can be concrete 101 for the its strength, longevity, and weight along with reinforcement 102 to unify the block 100 during manufacturing, transportation, and installation, creating an engineered product adhering to design structural codes and standards for use and safety. The profile shape of the block 100 can include a radius 103 that within a suitable tolerance is the same as the inside diameter of the pipe 200 associated therewith, so as to conform to the general inside diameter of the pipe 200 size being used. Such tolerance provides a frictional fit due to the mass of the block 100 as the block 100 rests upon the pipe 200 at predetermined suitable intervals, providing a great reduction of seepage of water between the block 100 and the pipe 200 , and provides the forces necessary to mechanically lock joints by using gravity due to the mass of the block 100 gravity force and the opposite or opposing force of the material under the pipe 200 . [0025] The thickness of the radius concrete 104 induces turbulence as fluids flow over them and between the installed blocks 100 and the interior of the pipe 200 surface intentionally to reduce water flow energy with the added result of the settlement of sediment within the system to be cleaned out periodically, and which stops sedimentation from flowing down stream to natural waters and provides the advantage of the turbulence oxygenating the water to aid in the bio degradation of organics in the water. [0026] A top portion 105 connects the internal radius structural element to the external two legs 106 , which sit outside of the piping 200 being used. The design is such to allow for lifting of the block 100 with various rigging methods and to allow variability for thickness of the wall of the pipe 200 manufactured by various styles or designs. The two legs 106 are vertical and include a height 107 of approximate determination related to the radius 103 and thickness 104 of the pipe 200 used, plus an increased minor addition 108 of approximately 2 inches to allow the legs 106 to settle into the earth a minimal amount before the exterior of the pipe 200 being held down contacts graded base material and undergoes the process of natural settlement of the legs 106 alone as time goes by. This allows the piping system to balance the distribution of static and dynamic, natural and induced forces, between the bottom of the exterior pipe 200 and the legs 106 after legs 106 are initially settled. The lengthening of the legs 106 to the length 107 provide an initial settlement of the block 100 into the soils to prevent the tangential forces shifting of the block 100 after placement and during the exterior backfilling of the piping system against exterior walls and blocks. [0027] As shown in FIG. 1 , the height by H 1 relates to the pipe diameter and concrete thickness. The width W 1 is the pipe thickness (e.g., 2 inches or more). The inside pipe diameter is shown by D 1 . The height H 2 relates to the concrete thickness. The width W 2 can be around a minimum of 5 inches. The legs 106 are tapered as shown by T 1 so as to be wider at the bottom for assisting form release, and the like. The pipe thickness T 2 can be variable, as needed. The width W 3 can relate to the pipe thickness, for providing additional space, and based on the concrete thickness. [0028] In further illustrative embodiments, the profile of the section 105 need not be square shaped at the internal and external edges or corners, and the like. For example, the transition direction changes at the section 105 can have a curved shape (e.g., as in FIG. 4D ) or any other suitable geometrical shape, and the like, for manufacturing, structural, or esthetic, and the like, purposes, as will be appreciated by those of ordinary skill in the relevant art(s). [0029] The depth dimension 109 (e.g., or side width of the block 100 sitting longitudinal on the half pipe 200 ) of the block 100 can be a calculated dimension for the calculated weight of the novel block 100 for the following reasons. The block 100 induces the natural force of gravity to counteract the natural lifting force of buoyancy. The buoyancy of a piping system used in areas with a fluid nature can be subject to the lowering of frictional soil values and the natural laws of engineered displacement of fluids. The block 100 induces the natural forces of gravity to counteract the natural lifting force of frost. Since some installation of the system can include areas subject to frost of various depths and may not be of a diameter radius depth to be below the established frost line, the block 100 can use the element of mass to reduce this frost force. The block 100 mass is also a factor to determine spacing of the blocks 100 set on the continually installed pipe 200 . A cost analysis of production, handling, transporting, and installation can determine a suitable spacing, center to center, for example, of 10 lineal feet, and the like. However, alternate sizing with a relationship to mass and material type and joint spacing can be altered to fit specific conditions including the complete lining of the plastic pipe 200 . This alternate use lends itself to the upward extension of the legs to produce a “wall” effect above the original system technology cast as part of the block unit. Advantageously, the dimensional depth in conjunction with concrete block 100 thickness aides in the spanning of the joints held in place by the mass creating frictional values between base material to plastic, plastic to plastic, plastic to concrete, while compressing the joint between the base material and the block 100 . [0030] As shown in FIG. 2 , the block 200 can employ the reinforcements 102 that are cage bar centered as shown by CBC, and which can be based on industry standards, codes, and the like, as needed. The reinforcements 102 can include variable cross pieces for reinforcement, cage stabilization, lift hook extensions, and the like. [0031] As shown in FIG. 3 , the length L can vary, as needed, and the cut pipe 300 can be made from a common ribbed plastic pipe, and the like. The cut pipe 300 can include bell and spigot lap joint ends 202 . [0032] In FIG. 4 , alternate variations of the blocks 100 and potential uses of the system are shown. The pipe blocks 100 can be manufactured in profiles to range from vertical 110 to horizontal 111 installations. The pipe blocks 100 also can be manufactured to radian 112 sections for wide but shallow uses. The blocks 100 can be manufactured to allow an angled (e.g., any suitable angle between 110 to 111 ) installation of the pipe 200 for desired installation. The blocks 100 can be manufactured to allow an angled installation of the pipe to aid in wave or tide water from fully extending into a shore line. This use has the potential of a fast and temporary installation to hinder the travel of pollutants floating on water from intrusion into inland areas. Short installations in midstream are possibilities for material control for the potential of redirecting flow to stop downstream bank erosion (e.g., one piece installed and then covered with big rock unifies the rocks so water acts against the unit of rocks instead of each individual rock). [0033] As shown in FIG. 4A , a plastic pipe can slide into the pipe block 110 for vertical position of pipe section, as shown by S. In FIG. 4B , the pipe block 112 can be configured for a radian section, wide but shallow installation. In FIG. 4C , the pipe block 111 can be configured for normal applications. In FIG. 4D , the pipe block 130 can be configured with curved shapes. [0034] In FIG. 5 , an under pipe barrier section 113 is shown. The precast concrete section 113 can be of a considerable size larger than the pipe 200 section for the purpose of stopping flowing water on the outside of the pipe block system to aid in erosion control, line, and grade of pipe 200 being installed in conjunction with normal installation of pipe blocks 100 . The pipe barrier section 113 can be employed at the beginning and end sections of the system and/or wherever deemed necessary. The elements of the barrier 113 include a reinforced slab of concrete with lifting holes 116 . A partial circumference relating to the exterior diameter of the ribbed exterior wall of the pipe being used is molded at 114 . A novel portion of the barrier 113 is the integral formed lip 115 that is sized to fit between the plastic pipe 200 ribs. The weight of the pipe block above completes the mechanical connection that virtually prevents water flow passing along the outside of the pipe block system to stop erosion and resulting displacement or settlement of the surround backfill. This is also a benefit to tangential above grade connections for surface drainage with our without a main tributary system. Formed in place, the lifting holes 116 add convenience to the barrier 113 . [0035] In FIG. 6 , an end pipe barrier section 117 is shown. The barrier 117 is best used at the upstream end of a pipe system, but can also be used at the downstream end piece, if caution of seepage is addressed with sealant materials. The purpose of the barrier 117 is to disallow water passage to the outside of the pipe system to avoid erosion or the costly installation of onsite cast in place methods. The elements are novel in that a simple placement of the pipe 200 used is fitted into the cast in place groove 118 for preventing the pipe 200 from horizontal and vertical motion up or down or sideways. In conjunction with the placement of a pipe block 100 adjacent to the end barrier 117 , the weight of the designed block 117 prevents lifting from buoyancy or frost lift while using the extent of bottom surface area of the pipe block 100 and barrier 113 counteracting settlement. The overhang lip 119 replicates the profile of the interior shape in a normal pipe block 104 allowing for continuity of the system. Lifting holes 120 are of value for lifting of the barrier 117 for manufacturing, transportation, and installation as well as removal for maintenance or re-use. [0036] In FIG. 7 , an end barrier closing block section 121 is shown. The closing block 121 is manufactured to sit within the end pipe barrier 117 to close off the entire end at the beginning or end of a pipe block system. Placement at of the closing block 121 on the inside or outside of the end pipe barrier 117 is determined by the purpose needed and soil conditions and the feeding method into the pipe block system. The block 121 benefits from dimensional stability and weight to remain in place. The extended lip 122 aligns against the parallel surface of the end pipe barrier 117 and prevents tangential movement in horizontal directions due to soils positioned against the backside on upstream installation, or the additional connection of drilled in place drop pins for downstream applications or as additional locking of the block to the end barrier. As with other components, a lifting hole 123 provides for safe and easy movement of the component. [0037] In FIG. 8 , the drainage management systems is shown, for example, including the pipe block 100 , the cut pipe 200 , the end pipe barrier 113 or 117 and the closing block 121 that fits on the end pipe barrier 117 (not shown). Thus, the drainage management systems and methods of the present invention can include the reinforced concrete blocks of FIGS. 1-2 and 4 - 8 and the pipes 200 of FIG. 3 shaped to line ditches for controlling movement of channeled water, tides, or waves from bodies of water. The application of the drainage management systems and methods counteract the natural forces of buoyancy and frost lift, stop erosion of bottom soils and stop bank sloughing due to soil saturations at the base flow line and vertical erosion undermining side banks. In the common installation of lining an open ditch, the pipe 200 of FIG. 3 lines a minimal lower portion of an open natural conveyance system for water or fluid drainage and is kept on line and grade by the mass of the concrete blocks of FIGS. 1-2 and 4 - 8 counteracting buoyancy and frost lift. The variations for vertical, angled, or normal installations are variable in all parameters of dimensions or site conditions and for the purpose intended. The profile of pipe 200 of FIG. 3 can be of any suitable radian degree so as to meld with the shape of the pipe blocks of FIGS. 1-2 and 4 - 8 . [0038] Advantageously, the drainage management systems and methods of the present invention employ common manufactured materials in a different form, require minimal cost of manufacturing and handling, provide a system not in existence of such simplicity and cost through all phases of production, transportation, installation, provide a product reducing long term maintenance and repair, provide a product completely recyclable or reusable or relocated, stop ditch bottom erosion, stop side bank sloughing, clean sediment out of water, oxygenate water, reduce water flow energy with minimal capacity rate change, provide a low tech production and installation product easily learned in the field, are usable as a method for shoreline disaster pollution, are usable as a stream or river side bank erosion possibilities, are usable as an in stream diversion to avoid downstream bank erosion, and are usable as an irrigation distribution system, and the like. [0039] Although the systems and methods of FIGS. 1-8 are described in terms of being employed for drainage management, and the like, the systems and methods of FIGS. 1-8 can be employed for other types of suitable applications where water flow and erosion management are desired, as will be appreciated by those of ordinary skill in the relevant art(s). [0040] While the present inventions have been described in connection with a number of illustrative embodiments, and implementations, the present inventions are not so limited, but rather cover various modifications, and equivalent arrangements, which fall within the purview of the appended claims.	Systems and methods for drainage management, including a pipe that is cut along a longitudinal section thereof; and a pipe block having a curved section corresponding to a diameter of the cut pipe and including supporting legs. The curved section of the pipe block is configured to support the cut pipe.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION [0001] This invention relates to an modified process for hydrocarbon recovery from an underground reservoir by in situ combustion and employing a horizontal production well. BACKGROUND OF THE INVENTION [0002] Commonly assigned U.S. Pat. No. 5,626,191 issued May 6, 1997 (hereinafter the '191 patent) discloses an in situ combustion processes for producing hydrocarbon from an underground hydrocarbon reservoir utilizing (i) at least one injection well placed relatively high in an oil reservoir for injecting an oxidizing gas into the hydrocarbon formation, and (ii) a production well for producing liquefied or gasified hydrocarbon from the hydrocarbon reservoir. The production well has a vertical section which is in communication with a horizontal leg extending substantially perpendicularly outwardly from the vertical section and having a “toe” portion and a “heel” portion. The horizontal leg is completed relatively low in the reservoir, and at a “heel” portion thereof is in communication with the vertical section. Air, or other oxidizing gas, such as oxygen-enriched air, is injected through the injection well into the hydrocarbon reservoir, typically via perforations in the upper part of a vertical injection well, located in the vicinity of the “toe” of the horizontal leg of the production well. The horizontal leg of the production well is oriented generally perpendicularly to a generally quasi-vertical combustion front of combusting hydrocarbon which is produced upon ignition of a portion of the hydrocarbon in the reservoir proximate the injection well. Such combustion front is supplied with oxidizing gas via the injection well. The “toe” of the horizontal leg portion is positioned in the path of the advancing combustion front. The resulting combustion front propagates from the “toe” of the horizontal leg along the horizontal leg in the direction of and towards the “heel” portion. During this process heated hydrocarbon in the reservoir in advance of the moving combustion front becomes liquefied or gasified and flows into the horizontal leg, and from such leg thereafter removed to the surface via the vertical section of the production well. This process of U.S. Pat. No. 5,626,191 is called “THAI™”, an acronym for “toe-to-heel air injection”, and a registered trademark of Archon Technologies Ltd., a subsidiary of Petrobank Energy and Resources Ltd, Calgary, Alberta, Canada. [0003] U.S. Pat. No. 6,412,557, also commonly assigned, discloses a similar but modified process having the added step of placing a hydrocarbon upgrading catalyst along, within, or around the horizontal leg to substantially decrease the viscosity of the hydrocarbon and upgrade the quality of the hydrocarbon and increasing the flow of hydrocarbon from the reservoir into the horizontal leg of the production well for subsequent removal to surface. Such modified process is known in the industry by the trademark CAPRI™, likewise a registered trademark of Archon Technologies Ltd. [0004] WO2005121504 (PCT/CA2005/000833) published Dec. 12, 2005, also commonly assigned, teaches a similar process to that of THAI™, further comprising the additional step of providing injection tubing inside the production well within the vertical section and substantially along the length of the horizontal leg to a position proximate the “toe” thereof, for the purpose of injecting a non-oxidizing medium comprising steam, water, or a non-oxidizing gas via said tubing to the “toe” region of said horizontal leg. The injection of such non-oxidizing medium into the “toe” region of the horizontal leg has the effect of displacing any oxidizing gas in such area and thus preventing combustion of upgraded hydrocarbon which has flowed into the horizontal leg, and further increases the ambient pressure in the horizontal leg so as to prevent or reduce further inflow of oxidizing gas from the injection well which is injecting oxidizing gas into the hydrocarbon reservoir. [0005] Disadvantageously, in each of the above prior art methods for recovering liquefied and/or gasified hydrocarbons from a hydrocarbon formation oxidizing gas is needed to be injected proximate the toe of the horizontal leg, and remote from the vertical section of the production well. Such site of injection of oxidizing gas is remote from the vertical section of the production well, the surface of the production well being the location where oxidizing gas is typically generated. The injection and vertical section of the production wells can be separated by one (1) kilometer or more. Thus such prior art methods thus typically require transport of the oxidizing gas to the site of the injection well via piping from the production well, or alternatively require installation of equipment at the injection well site to permit generation of oxidizing gases for subsequent injection. Such requires clear access, via clearcutting, and/or increased space at the injection well site to accommodate additional oxidizing gas delivery and/or generation and compression facilities, thereby increasing the environmental “footprint” and impact of drilling operations on the environment, and also typically results in increased cost. [0006] Thus a need thus exists for a modified process of THAI™ and CAPRI™ wherein such drawbacks are eliminated. SUMMARY OF THE INVENTION [0007] The method of the present invention is to a modified in situ hyrdrocarbon recovery process that instead of injecting oxidizing gas near the “toe” portion of the horizontal leg injects oxidizing gas in or near the producing vertical section of the producing well (ie at the “heel” portion). The modified process obviates the need for a separate drilling/production pad for oxidizing gas injection, thereby reducing cost and decreasing detrimental environmental impact of in situ recovery methods. [0008] Advantageously, the process of the present invention in a particular third embodiment described below further eliminates the need for a separate oxidizing gas injection well, in that in such refinement the vertical section of the production well also serves as the injection well, thereby reducing well drilling costs and reducing the capital costs. [0009] Specifically, rather than being a “toe-to heel” process, the process of the present invention is a “heel-to-toe” process. The oxidizing gas injection point is modified to be at the “heel” as opposed to the “toe” so that the combustion front moves in the opposite direction from that of the THAI™ process, namely from the direction of the “heel” of the horizontal well towards the “toe”. [0010] In the present invention three regions of the reservoir are developed relative to the position of the combustion zone. Near the “heel” and after the passage of the combustion front away from the “heel” lies the burned oil-depleted zone which results after injection of the oxidizing gas and after the combustion front has advanced for a period outwardly and away from the injection well and the “heel” portion of the horizontal leg. Such burned zone is filled substantially with oxidizing gas. Next lies the coke zone, which is essentially the area within the reservoir which the oxidizing gas has been able to then penetrate in the reservoir, and is essentially the area at which the combustion front exists (the combustion which occurs being that of the remaining coke which is the hydrocarbon then remaining after the lighter hydrocarbons within such reservoir and ahead of such combustion front have been liquefied or gasified and have flowed into the horizontal leg and thereafter removed to surface. Lastly, towards the “toe” of the horizontal well lies the region of the reservoir containing hydrocarbons which the combustion front is advancing toward. [0011] At higher oxidant injection rates, reservoir pressure increases and oxidizing gas in the burned zone, containing residual oxygen, can be forced into the horizontal leg of the production well. This is prevented in the process of the present invention by injecting, either for a limited time, or continuously, a medium such as a non-oxidizing gas such as carbon dioxide, and/or steam or water, to increase the pressure within the horizontal leg of the production well. [0012] Accordingly, in one broad aspect of the process of the present invention, to realize the advantage of being able to inject the oxidizing gas proximate or in the vertical section of the production well, a modified process for recovering liquefied or gasified hydrocarbon from an underground hydrocarbon reservoir is disclosed, comprising the steps of: [0013] (a) providing at least one production well having a substantially horizontal leg positioned relatively low in said reservoir, said horizontal leg having at one end thereof a heel portion and at an opposite end thereof a toe portion, said horizontal leg adapted to permit inflow of hydrocarbon into an interior of said horizontal leg, said production well having a substantially vertical section connected to said horizontal leg proximate said heel portion thereof; [0014] (b) providing production tubing inside said production well extending within said vertical section and within at least a portion of said horizontal leg to collect said hydrocarbon which flows into said horizontal leg; [0015] (c) injecting periodically or continuously a medium into the horizontal leg proximate the heel portion thereof, wherein said medium is selected from the group of mediums comprising alone or in combination, a non-oxidizing gas such as carbon dioxide, steam, or water; [0016] (d) supplying an oxidizing gas to said underground reservoir, at least initially, at a location of or proximate said vertical section of said production well; [0017] (e) igniting hydrocarbon within said hydrocarbon reservoir proximate said injection well, so as to cause combustion of a portion of said hydrocarbon in said hydrocarbon reservoir proximate said vertical section and thereby create a combustion front which advances outwardly and away from said injection well in at least a direction along said horizontal leg and towards said toe portion thereof; [0018] (f) causing heated hydrocarbon from said reservoir to flow from upper regions thereof and collect in said horizontal leg; and [0019] (g) removing from the production well, via said production tubing, said hydrocarbon which has flowed into said horizontal leg. [0020] Regarding step (g) above, the removal of the hydrocarbon from the production well via the production tubing is typically without pumping, but may require pumping in order to be removed from the horizontal leg if sufficient quantities of inert gases such as gasified hydrocarbon, carbon dioxide or nitrogen do not flow into the horizontal leg and thus the production tubing under significant ambient pressure of the hydrocarbon formation, as may occur during a start-up period. The normal mechanism of producing oil by reducing the mixed-fluid density with gases is called ‘gas lift’. [0021] In a first refinement/embodiment of the above process of the present invention, the injection of the oxidizing gas proximate the vertical section of the production well is accomplished via the drilling of a separate injection well proximate the vertical section of the production well so as to permit the oxidizing gas to be injected into the formation via such injection well proximate the production well. In this manner, and advantageously, the same drilling pad can then be used for drilling both the production well and the injection well, thus saving on expense and cost of well drilling. [0022] Additionally, and advantageously, because the injection well is situated proximate the production well which typically has power generation equipment used for production, oxidizing gas can usually and more easily be obtained and immediately injected into the injection well, which would not otherwise be capable of being done were the injection well positioned remote from the vertical section of the production well as in the prior art. [0023] In a second embodiment of the invention, the injection well is a side entry well within the vertical section of the production well, thus again allowing the injection well to be situated proximate the injection well so as to achieve the above benefits, as well as the additional benefit in that the upper portion of the vertical section of the production well can be used when drilling the side entry well, thus further reducing drilling costs. [0024] Specifically, in such second preferred embodiment, the present invention comprises a process for recovering liquefied or gasified hydrocarbon from an underground hydrocarbon formation comprising the steps of: [0025] (a) providing at least one production well having a substantially horizontal leg positioned relatively low in said formation, said horizontal leg having at one end thereof a heel portion and at an opposite end thereof a toe portion situated in the formation slightly lower in elevation than said heel portion, said horizontal leg adapted to permit inflow of liquefied hydrocarbon into an interior of said horizontal leg, said production well having a substantially vertical section connected to said horizontal leg proximate said heel portion thereof; [0026] (b) providing production tubing inside said production well extending downwardly within said vertical section and along said horizontal leg to said toe portion, to collect said hydrocarbon which flows into said horizontal leg; [0027] (c) providing injection tubing in said production well, said injection tubing extending downwardly in said vertical section to said heel portion; [0028] (d) injecting a medium into said production well via said injection tubing wherein said medium is selected from the group of mediums comprising alone or in combination, a non-oxidizing gas, steam, water, or carbon dioxide; [0029] (e) providing an injection well as a side track re-entry from said vertical section of said production well, which injection well extends into the hydrocarbon formation; [0030] (f) supplying an oxidizing gas to a portion of said hydrocarbon formation via said injection well; [0031] (g) igniting said hydrocarbon in said hydrocarbon formation proximate said vertical section so as to cause combustion of a portion of said hydrocarbon in said hydrocarbon formation and thereby create a combustion front which advances outwardly and away from said vertical section in at least a direction along said horizontal leg and towards said toe portion thereof; and [0032] (h) removing from the production well, via said production tubing, hydrocarbon which has flowed into said horizontal leg. [0033] In a third preferred embodiment the present invention comprises a method of producing hydrocarbon from a hydrocarbon reservoir whereby the necessity of an injection well for injecting the oxidizing gas is completely eliminated, thus reducing the cost of implementing the in situ process of the present invention. [0034] Specifically, in such third and preferred embodiment of the present invention, the vertical section of the production well is perforated to permit an oxidizing gas (which is provided to such vertical section) to escape into the hydrocarbon formation proximate the vertical section. In such manner, the need to drill a separate injection well is eliminated. [0035] Again, as part of the method of the present invention, a medium in the form of a non-oxidizing gas such as carbon dioxide, steam or water is injected either continuously or intermittently into the production well via injection tubing, which extends to the heel portion of the production well. A series of “packers” located in the production well may be provided to isolate the oxidizing gas supplied to the vertical section of the production well from the heel portion of the horizontal leg of the production well to which the non-oxidizing medium is supplied. [0036] Thus in such third preferred embodiment, the method of the present invention comprises a process for recovering liquefied or gasified hydrocarbon from an underground hydrocarbon reservoir, comprising the steps of: [0037] (a) providing at least one production well having a substantially horizontal leg positioned relatively low in said reservoir, said horizontal leg having at one end thereof a heel portion and at an opposite end thereof a toe portion, said horizontal leg adapted to permit inflow of liquefied hydrocarbon into an interior of said horizontal leg, said production well having a substantially vertical section connected to said horizontal leg proximate said heel portion thereof; [0038] (b) providing production tubing in said production well, extending from a surface of said production well to at least said heel portion of said production well to collect said hydrocarbon which flows into said horizontal leg; [0039] (c) providing injection tubing in said production well, said injection tubing extending downwardly in said vertical section to a position extending into at least said heel portion of said horizontal leg; [0040] (d) injecting a medium into the production well, wherein said medium is selected from the group of mediums comprising alone or in combination, a non-oxidizing gas such as carbon dioxide, steam, or water; [0041] (e) providing perforations in said vertical section of said production well at a position above said heel portion; [0042] (f) supplying an oxidizing gas to said vertical section and thus to a portion of said hydrocarbon reservoir via said perforations in said vertical section; [0043] (g) igniting said hydrocarbon in said hydrocarbon reservoir proximate said vertical section so as to cause combustion of a portion of said hydrocarbon in said hydrocarbon reservoir and thereby create a combustion front which advances outwardly and away from said vertical section in at least a direction along said horizontal leg and towards said toe portion thereof; and [0044] (h) causing heated hydrocarbon from said reservoir to flow from upper regions thereof and collect in said horizontal leg; and [0045] (i) removing from the production well, via said production tubing, said hydrocarbon which has flowed into said horizontal leg. [0046] Advantageously, the third embodiment of the present invention also eliminates the need as in the prior art to “close off” (using a cement plug or the like) the horizontal leg of each production well when a series of production wells are situated end to end and when the vertical section of a first production well is subsequently converted to an injection well (see. US '191, col 6, lines 47-col 7, line 9 and FIGS. 14D-F thereof). The in situ method of the present invention, in particular the third embodiment, is a method of further reducing the cost of in situ recovery by reducing the number of steps, including not only eliminating the need to drill injection wells but also eliminating the necessity of “closing off” other wells as is necessary in the in situ methods of the prior art, as exemplified in US '191 above. BRIEF DESCRIPTION OF THE DRAWINGS [0047] In the accompanying drawings, which illustrate a number of exemplary embodiments of the invention: [0048] FIG. 1A is a perspective schematic view of a prior-art in situ recovery arrangement in a hydrocarbon reservoir, showing air injection wells situated at the toe of each of corresponding horizontal legs of associated production wells; [0049] FIG. 1B is a cross section through one injection well and associated production well shown in FIG. 1A ; [0050] FIG. 2A is a schematic cross-section (not to scale) through one injection well and associated production well of a first embodiment of the present invention, using the method of the present invention of causing a combustion front to propagate in the direction of the “toe” of the horizontal leg of the production well, at a point in time close to the time of ignition of the hydrocarbon and the initial propagation of the combustion front; [0051] FIG. 2B is a similar cross-section to that of FIG. 2A , likewise not to scale, at a subsequent point in time when the combustion front has propagated for a time and moved closer to the “toe” portion of the horizontal leg of the production well; [0052] FIG. 2C is a similar cross-section to that of FIG. 2B , likewise not to scale, at a still further point in time when the combustion front has further propagated and moved even closer to the “toe” portion of the horizontal leg of the production well; [0053] FIG. 3 is a schematic partial cross-section through a hydrocarbon reservoir containing a hydrocarbon-containing formation, which shows a second embodiment of the method of the present invention, namely a production well and associated side entry injection well (not to scale) and further depicting the method of the present invention of causing a combustion front to propagate in the direction of the “toe” of the horizontal leg of the production well, at a point in time close to the time of ignition of the hydrocarbon and the initial propagation of the combustion front; [0054] FIG. 4 is a schematic partial cross-section through a hydrocarbon reservoir containing a hydrocarbon-containing formation, which shows a third preferred embodiment of the present invention, namely a cross-section through a production well (not to scale) employing the method of the present invention of causing a combustion front to propagate in the direction of the “toe” of the horizontal leg of the production well, at a point in time close to the ignition of the hydrocarbon and the initial propagation of the combustion front; and [0055] FIG. 5 is a perspective schematic view of an in situ recovery method of FIG. 4 , showing the third and preferred embodiment of the method of the present invention for recovering hydrocarbons from a hydrocarbon reservoir DESCRIPTION OF THE PREFERRED EMBODIMENT [0056] FIG. 1A shows a schematic, semi-transparent view of an arrangement of wells utilized in the prior art for in situ recovery of hydrocarbon from a subsurface hydrocarbon reservoir or formation 10 . [0057] Specifically, FIG. 1A schematically depicts the prior art method of in situ recovery of hydrocarbon disclosed in U.S. Pat. No. 5,626,191, comprising locating a series of production wells 12 , each comprising a substantially vertical section 16 and a substantially horizontal leg 16 , having a “toe” portion 18 and a “heel” portion 20 . The horizontal leg 16 of production well 12 is located at a lower region of hydrocarbon formation 10 , and is substantially porous to allow ingress of fluids. A series of injection wells 22 are provided, situated at a region proximate the “toe” and extending downwardly into the formation 10 , with perforations in the upper reaches of the oil-bearing reservoir. [0058] FIG. 1B shows a schematic cross-section through an injection well 22 and associated production well 12 of FIG. 1A . [0059] In the prior art in situ recovery process depicted in FIGS. 1A & B, an oxidizing gas 24 , such as air (which contains oxygen), oxygen, or oxygen-enhanced air, is injected into the formation 10 via each of injection wells 22 , so as to permit a portion of the hydrocarbon in formation 10 to be combusted. Specifically, a portion of the hydrocarbon in hydrocarbon formation 10 in the region of the injection well 22 when supplied with the oxidizing gas 26 is caused to be ignited and caused to combust, thereby forming and creating within formation 10 a substantially vertical and laterally-extending combustion front 26 . Such combustion front 26 , by way of heat conduction and creation of heated combusted gases within formation 10 , heats hydrocarbons in the formation 10 directly ahead and in advance of combustion front 26 , causing the more volatile hydrocarbon compounds in formation 10 to gasify and further cause upgrading of a portion of the hydrocarbon solids or bitumens in the formation simultaneously increasing their viscosity so as to create mobile liquefied hydrocarbons 30 . The remaining heavier hydrocarbons, particularly coke, remain, which provide fuel for the advancing combustion front 26 and sustain the advance of the combustion front 26 and the in situ combustion and hydrocarbon upgrading process. Then mobile liquefied hydrocarbons 30 and gasified components (some of which may subsequently condense as liquids 30 ), then flow downwardly by action of gravity through the formation and are collected in a lowermost region of the formation 10 by flowing into horizontally-extending horizontal leg 16 of the production well 12 . Horizontal leg 16 of production well 12 generally has, at least for a limited time, a gas pressure therein less than that of the formation 10 (due to removal of collected liquid hydrocarbons 30 as well as gaseous hydrocarbons therefrom), Such reduced gaseous pressure in horizontal leg 16 as opposed to within formation 10 in advance of combustion front 26 assists in liquid and gaseous hydrocarbon inflow from hydrocarbon formation 10 into the horizontal leg 16 . At other times, due to injection of medium 52 via injection tubing 50 (discussed below) into horizontal leg 16 , horizontal leg 16 may at times may have a gaseous pressure close to, or even in excess of the gas pressure within formation 10 . [0060] Importantly, in the prior art method of in situ recovery as shown in FIGS. 1A & B and described above, injection wells 22 are situated proximate the “toe” of the horizontal leg 16 , and oxidizing gas injected into the formation at these locations via the injection wells 22 . The combustion front 26 which receives oxidizing gas 24 is thus caused to progress outwardly from the injection well 22 , and perpendicular to and along the horizontal wells 16 in a direction from the “toe” portion to the “heel” portion. [0061] Disadvantageously with this prior art method, not only need a drilling pad 32 be created for the production well 12 , but an additional and separate drilling pad need be created for the injection well 22 , and such separate injection well 22 need be drilled into such formation. In addition, oxygen creation and injection equipment (not shown) must be hauled to and installed at the surface of such injection well 22 , as such injection well is remote from the surface of production well 12 . Both of such requirements add significantly to the cost of carrying out the prior art methods of in situ recovery of hydrocarbons. [0062] FIGS. 2A-2C herein show a modified (first) in situ recovery process, which is expressly adapted to eliminate at least one of the above expenses in the prior art methods of in situ hydrocarbon recovery, namely the expense of creating a separate drilling pad for the injection well 22 . [0063] Specifically, as seen in FIGS. 2A-2C , a single drilling pad 32 is created by way of clearing of trees and other obstacles, and a single drill platform erected thereon. A production well 12 is drilled using conventional drilling techniques, comprising a vertical section 14 , and a further horizontal leg 22 in communication with vertical section 14 . The horizontal leg 16 has a “toe” portion 18 and a “heel” portion 20 where it meets vertical section 14 . The production well 12 is completed by the usual process of casing well 12 , and further by the insertion within such production well 12 of production tubing 40 , which extends downwardly in vertical section 14 to such heel portion 20 and preferably along the horizontal leg 16 , preferably to toe portion 18 thereof, such production tubing 40 having an open end 42 within said horizontal leg 16 . Production tubing 40 is typically coiled tubing as is conventionally used in drilling operations. [0064] Additional injection tubing 50 , likewise typically coiled tubing as is conventionally used in drilling operations, is further provided for injection of a medium 52 into production well 12 , such medium 52 comprising a non-oxidizing gas, preferably carbon dioxide due to its diluent effect on hydrocarbons, or alternatively or in combination steam or water or other non-combustible flowable medium. As seen from FIGS. 2A-2C , injection tubing 50 extends into the “heel” portion 20 of horizontal leg 16 . At least one isolation packer 54 is provided to allow medium 52 to be injected, if desired, in a pressurized state from time to time or continuously injected, so as to pressurize from time to time or continuously if desired, horizontal leg 16 to assist in forcing liquefied hydrocarbon 30 into production tubing 40 and inhibiting entry of oxidizing gas into the horizontal leg 16 . [0065] Using the single drilling pad 32 , a further injection well 22 is drilled, extending into at least the upper region of the hydrocarbon formation 10 . Injection well 22 typically has perforations 75 in a lower end thereof to permit infusion and injection of an oxidizing gas 24 such as air or oxygen into the hydrocarbon-containing region of hydrocarbon formation 10 . [0066] The method of the present invention, in the first embodiment shown in FIGS. 2A-2C , thereafter operates as follows: [0067] Oxidizing gas 24 is injected into formation 10 via injection well 22 . Advantageously, equipment (not shown) used to create oxidizing gas 24 and inject such oxidizing gas 24 need not be located remote from the production well 12 , but instead can, by virtue of the method of the present invention, be located proximate to production well 12 , and in particular if desired may be located on drilling pad 32 or closely proximate thereto, thereby eliminating the need for clearing and creating a separate drilling pad at a remote site such as would occur if the injection well 22 were located towards the “toe” of horizontal well 16 . Also, operation and maintenance of the oxidizing gas supply equipment can conveniently be conducted at the oil-treating site located near well 12 . Hydrocarbons proximate the injection well 22 are ignited, and due to the supply of oxidizing gas 24 , a combustion front 26 is created, which in the method shown in FIGS. 2A-2C , advances as a substantially vertical laterally extending front (see also FIG. 5 herein) from the “heel” 20 of horizontal leg 16 towards the “toe” 18 . Viscous and high viscosity hydrocarbons, including bitumen, in the hydrocarbon formation 10 in advance of the advancing combustion front 26 , due to heat which is generated, are caused to upgrade and become liquid, and in the process become less viscous. Some hydrocarbons in the formation 10 in advance of the front 26 will gasify. Liquified hydrocarbons 30 and gasified hydrocarbons, now being mobile, flow downwardly and into horizontal leg 16 which is made porous (ie has apertures 60 in an upper portion thereof) to permit infusion of such hydrocarbons 30 and thus collection of such hydrocarbons 30 . [0068] Such process continues as combustion front 26 progresses and thus “sweeps” from the “heel” portion 20 to the “toe” 18 of horizontal leg 16 . [0069] Notably, prior to generation of combustion front 26 , hydrocarbon formation 10 is preferably initially preheated by injection of a heated non-oxidizing medium 52 such as steam, which is injected into the horizontal leg 16 of production well 12 via injection tubing 40 , and removed via production tubing 50 or alternatively via annulus 80 in vertical section 16 if isolation packers 54 are not present. Pre-injection of a heated medium has the benefit of heating the production well 12 and its production components thereby increasing the flowability of liquefied hydrocarbons 30 which flow into horizontal leg 16 of production well 12 . This procedure is useful in bitumen reservoirs because cold oil that may enter the horizontal leg 16 will be very viscous and will flow poorly, possible plugging the horizontal leg 16 . For formations 10 with mobile oil, extensive pre-ignition steaming is not required for the purpose of heating the oil so that it will flow, however, it can be useful to reduce oil saturations near the oxidizing gas injection well 22 and to raise the hydrocarbon temperature to achieve ignition thereof. Other ignition methods may be employed such as the injection of easily ignitable fuels such as linseed oil, or by injection of hot combustion gas. For bitumen reservoirs, steam is also injected via injector well 22 and may also be injected into the reservoir 10 in the region between the injector well 22 and the toe 18 of the horizontal well 16 to warm the oil and increase its mobility prior to initiating injection of oxidizing gas 24 into the reservoir formation 10 . [0070] After initiation of combustion and combustion front 26 , a non-oxidizing medium 52 in the form of steam, a non-oxidizing gas such as carbon dioxide, or water, is injected, either continuously or sporadically via injection tubing 50 into horizontal leg 16 , which due to isolation packers 54 , can be pressurized. The purpose of such non-oxidizing medium 52 is for a number of reasons. Firstly, increased pressure within horizontal leg 16 reduces or prevents oxidizing gas 24 infusing into horizontal leg 16 from formation 10 which could otherwise detrimentally, in combination with liquefied and gaseous hydrocarbons therein, form an explosive mixture with potentially explosive consequences, or alternatively react with oxygen directly so as to form coke which could otherwise seal the horizontal leg 16 of production well 12 . The consequence of having hydrocarbon (oil) and oxygen together in a wellbore is combustion and potentially an explosion with the attainment of high temperatures, perhaps in excess of 1000° C. This can cause irreparable damage to the wellbore, including the failure of the sand retention screens (not shown). The presence of oxygen and wellbore temperatures over 425° C. must be avoided for safe and continuous oil production operations. Secondly, injection of medium 52 can serve to pressurize horizontal leg 16 and assist in driving liquefied and gaseous hydrocarbons 30 collected in horizontal leg 16 into the open end 42 of production tubing 40 , thereby assisting in drawdown of such liquids 30 and producing such hydrocarbons 30 from producing well 12 . Thirdly, medium 52 when injected via injection tubing 50 can be heated. Advantageously, means for heating such medium 52 are, in this method, conveniently capable of being located at the surface of production well 12 and on or near drilling pad 32 . Lastly, where the injected medium 52 is carbon dioxide, injection thereof into horizontal well 16 serves as not only a convenient carbon “sink” to allow disposal of such greenhouse gas, but further due to the diluent properties on carbon dioxide on liquid hydrocarbons 30 , reduces the viscosity thereof and thus aids in the drawdown of collected liquid hydrocarbons 30 via production tubing 40 . [0071] As seen from FIGS. 2A-2C , during the advance of combustion front 26 , coke is deposited in the reservoir 10 and serves as fuel for the in situ combustion process. Hot combustion gases 70 advance into formation 10 heating the hydrocarbon therein and any connate water that is present. A portion of these hydrocarbons liquefies and such liquefied hydrocarbons 30 flow, along with combustion gases, into the horizontal leg 16 through the perforations 60 , as shown in FIGS. 2A-2C . The liquefied hydrocarbons 30 flow along and to the “toe” 18 of horizontal leg 16 and enter the open end 42 of production tubing 40 therein, and flow back and then upward to the surface. The process is stable and continuous, with the combustion front 26 continuously advancing towards the “toe” 18 of the horizontal leg 16 . [0072] The oxidizing gas 24 , typically air, oxygen or oxygen-enriched air, is injected into the upper part of the reservoir 10 . Coke that was previously laid down consumes the oxygen so that only oxygen-free gases contact the oil ahead of the coke zone at the combustion front 26 . Combustion gas temperatures of typically 600° C. and as high as 1000° C. are achieved from the high-temperature oxidation of the coke fuel. In the mobile oil zone 80 in advance of the combustion front 26 , these hot gases 70 and steam heat the oil to over 400° C., partially cracking the oil, vaporizing some components and greatly reducing the oil viscosity. The heaviest components of the oil, such as asphaltenes, remain on the rock and will constitute the coke fuel later when the combustion front 26 arrives at that location. In the mobile oil zone 80 , gases and oil drain downward into the horizontal leg 16 , drawn by gravity and at times by the low-pressure sink of the horizontal leg 16 when unpressurized. The coke zone at the combustion front 26 and the mobile oil zone 80 move laterally from the direction from the heel 20 towards the toe 18 of the horizontal well 16 . The burned zone section 100 behind the combustion front is depleted of liquids (oil and water) and is filled with oxidizing gas 24 . The section of the horizontal well 16 opposite this burned zone 100 is in jeopardy of receiving oxygen or oxidizing gas 24 which will combust the oil present inside horizontal well 16 creating extremely high wellbore temperatures that would damage the steel casing and especially the sand screens that are used to permit the entry of fluids 30 but exclude sand. If the sand screens fail, unconsolidated reservoir sand will enter the horizontal wellbore 16 and necessitate shutting for cleaning-out and remediation with cement plugs. This operation is very difficult and dangerous since the horizontal wellbore 16 can contain explosive levels of oil and oxygen. [0073] The method of the present invention contemplates a number of ways to prevent influx of oxidizing gas 24 from the formation 10 into the horizontal leg 16 . A first method is to reduce the injection rate of the oxidizing gas 24 in order to reduce the reservoir pressure in formation 10 . A second method is to reduce the liquefied hydrocarbon 30 drawdown rate via the production tubing 40 (ie reduce the production rate via production tubing 40 ) to thereby increase wellbore pressure in horizontal leg 16 . Both of these methods result in the reduction of hydrocarbon production rates, which is economically detrimental. An alternative and preferred method is that as described previously herein, namely the injection of non-oxidizing medium 52 into horizontal leg 16 via injection tubing 50 , which is believed to have little effect on gravity draining of hydrocarbon liquids into horizontal well 16 . In any event, such injection of medium 52 may be done periodically and only for a time sufficient to reduce concentrations of oxygen within horizontal leg 16 to less-than-explosive concentrations. In a typical operation, a thermocouple string can be placed along the horizontal section, or within, and the occurance of elevated temperatures will signal the intrusion of oxidizing gas so that water of steam may be added via tubing 52 to reduce well-bore temperatures, dilute the oxygen present and increase wellbore pressure to inhibit further oxidizing gas entry. [0074] FIG. 3 schematically illustrates a further more preferable embodiment of the method of the present invention, having similar components to those identified in FIGS. 2A-2C , and having similar methodology. Again, an oxidizing gas in injected into formation 10 via injection well 22 , and a combustion front 26 created which “sweeps” from heel 20 to toe 18 of horizontal leg 16 , causing liquefied hydrocarbons 30 as well as gasified hydrocarbons to flow into horizontal leg 16 and be delivered to surface via production tubing 40 . [0075] Notably, however, the important and sole distinction in the method of in situ recovery shown in FIG. 3 over the method previously discussed and as shown in FIGS. 2A-2C is that injection well 22 in the method depicted in FIG. 3 is formed as a side entry well from within vertical section 16 of production well 12 . [0076] Advantageously, using the method depicted in FIG. 3 , injection well 22 is less expensive to drill as an upper portion of such injection well has already been drilled as it is common with vertical section 16 of production well 12 . [0077] Accordingly, not only are cost savings realized in locating the injection well 22 at the location of and in close proximity to the production well 12 and its associated equipment and no separate drill pad 32 needed to be created, but in addition, well drilling costs are reduced when drilling injection well 22 . [0078] FIG. 4 depicts a third and most preferred embodiment of the method of the present invention for carrying out in situ recovery of hydrocarbon. Such method, like the first embodiment of the method of the present invention depicted in FIGS. 2A-2C , and like the second embodiment of the invention depicted in FIG. 3 , includes as an integral component of the method the creation of a combustion front 26 which “sweeps” from “heel” 20 to “toe” 18 of horizontal leg 16 , thereby causing liquid hydrocarbons 30 to be collected in horizontal leg 16 , and thereafter drawndown by production tubing 40 and produced to surface. [0079] Importantly, however, in this third embodiment of the method of the present invention shown in FIG. 4 , there is no step of drilling an injection well 22 . Instead, perforations 110 are made in the vertical section 16 of production well 12 , and an oxidizing gas 24 injected into such vertical section 16 and thus into formation 10 . Oxidizing gas 24 is prevented from injection into horizontal leg 16 by the presence of isolation packers 54 which effectively separate produced liquefied hydrocarbons in horizontal leg 16 from oxidizing gas 24 such as oxygen, thereby preventing formation of explosive mixtures. Injection tubing 50 still serves, like in earlier embodiments, to permit sporadic or continuous injection of non-oxidizing gas 52 into horizontal leg 16 to prevent oxidizing gas 24 within the burned zone 80 of the formation from permeating into horizontal leg 16 . [0080] Advantageously, using the method depicted in FIG. 4 , the cost of drilling an injection well 22 is completely eliminated. Accordingly, with the method depicted in FIG. 4 , not only are cost savings realized and environmental impact reduced in being able to have oxidizing injection apparatus at the production well and only on a single drill pad 32 at the production well which is otherwise the case in prior art methods which require creation of a separate drill pad and additional clearing for oxidizing gas creation and injection equipment (not shown), but in addition substantial cost savings are achieved by elimination the necessity to drill any injection well. [0081] FIG. 5 depicts how the method of FIG. 4 (ie the third embodiment of the method of the present invention) may be deployed with a series of production wells 12 in a hydrocarbon formation 10 , using a combustion front 26 which advances from “heel” 20 to “toe” 18 . [0082] Although the disclosure describes and illustrates preferred embodiments of the method of the present invention, it is understood that the invention is not limited to these particular embodiments. Many variations and modifications will now occur to those skilled in the art. For a full definition of the invention, reference is to be made to the appended claims.	A modified method of in situ recovery of hydrocarbon from an underground hydrocarbon-containing formation. An “L” shaped production well, having a vertical upper section, and a lower horizontally-extending leg which is positioned low in the hydrocarbon formation, is provided. The horizontal leg connects to the vertical section of the production well at a heel portion and has a toe portion at an opposite end thereof. An oxidizing gas is injected into the formation proximate the vertical section of the production well. A vertical combustion front is created which is caused to sweep outwardly therefrom and laterally within the formation above the horizontal leg, from the heel to the toe of the horizontal leg, causing hydrocarbons in the formation above the horizontal leg to be upgraded and liquify, and thereafter to drain downwardly into the horizontal leg which is permeable, where such liquified hydrocarbons are then delivered to surface via production tubing. A non-oxidizing gas is injected into the heel portion of the horizontal leg via injection tubing contained within the vertical section of the production well. Benefits of the modified method of in situ recovery include decreased costs and lessened environmental impact.
You are an expert at summarizing long articles. Proceed to summarize the following text: RELATED APPLICATION This application claims the priority of the Japanese Patent Application No. 10-223971 filed on Aug. 7, 1998. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the improvement of a portable fence, more specifically, relating to a practical portable fence capable of not only being stably installed in an easy and fast manner along a restricted area to keep off the unconcerned from construction or events-holding sites, but also being so compactly folded that it is convenient to carry and store. 2. Prior Art As well known, there is a restricted area to keep off the unconcerned at construction or events-holding sites in order to avoid risks and to secure a smooth operation of an event, and for such area, it is required to expressly indicate from where such area begins by closing it off with a rope or wire, or installing a fence along the boundary of such controlled area. But, with such prior arts as mentioned above, which are intended to be temporarily installed at such sites, it takes a lot of labor and time to put them into practice because it involves striking a plurality of piles with a regular interval therebewteen, standing poles enclosed with a rope or wire or with bars suspended therebetween. Also, upon releasing such restriction, it costs unreasonably high to remove such piles and waste such rope or wire and bars as mentioned above. Under the circumstances, recently, to define a keep-off area, such method for defining a restricted area is often used as comprising a gatelike fence component with legs provided at its lower end thereof and a foundation block with holes opened therein to receive said legs so as to put said fence component to stand. That is to say, according to this method, as a restricted area is established by disposing said foundation blocks with a certain interval therebetween along the boundary of such area and then inserting said legs into the holes of those foundation blocks, the installation work becomes easier in comparison with the above-mentioned prior arts, and it dispenses with the waste of the materials because those components can be repetitiously used. However, even with such method as described above, it takes a lot of labor and time not only to dispose those foundation blocks with a fixed interval therebetween by correctly measuring it, but also to insert a number of fence components into the holes of the foundation blocks. Furthermore, to release such restriction of entry or to remove and take out such prior fence, a number of such fence components respectively has to be detached from a number of such block foundations respectively, and it requires a wider space for the storage of those detachable components and foundations. SUMMARY OF THE INVENTION Thus, in view of the inconveniences encountered with the prior arts as mentioned above, the present invention is to provide a practical portable fence capable of being stably installed in an easy manner along the boundary of a restricted area to keep off the unconcerned and being so compactly folded that it is convenient to carry and store. To solve the above issue, the present invention discloses a portable fence with foldable components comprising a screen formed by connecting a plurality of fence components side by side by means of a hinge means such that they are foldable to each other and a stay relatively rotating to said fence component so as to adjust its plane angle with regard thereto for the stabilization thereof. The portable fence disclosed in this invention is easy and fast to join and disjoin at its hinged portions, and if made of a synthetic resin capable of blow or injection moulding, it further enhances its weight reduction and productivity. Furthermore, by the addition of a weight container mountable on the stay, the standing stability of the portable fence further improves. Hereinafter, the preferred embodiments of the present invention are concretely described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing a stay mounted on the lower part of a fence component of the portable fence embodied in the present invention. FIG. 2 is a side view showing the stay rotated substantially perpendicular to the fence component. FIG. 3 is an exploded perspective view showing two fence components connected to each other by means of bi-axial hinges. FIG. 4 is a frontal view of the portable fence embodied in the present invention showing ten fence components connected to each other by means of bi-axial hinges. FIG. 5 is a plan view showing the portable fence as shown in FIG. 4 folded. FIG. 6 is an exploded perspective view showing a weight container mounted onto the stay rotated perpendicularly to the plane surface of the fence component. FIG. 7 is a frontal view showing the portable fence embodied in the present invention installed in a linear course and the stays rotated perpendicularly to the fence components with weight containers mounted on the stays as arbitrarily selected. FIG. 8 is an installation example of the portable fence embodied in the present invention showing the fence installed in a restricted area with a sinuous course. FIG. 9 is an exploded perspective view showing a modified embodiment of the stay for the portable fence embodied in the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT In FIGS. 1 to 6 , numeral 1 indicates a fence component of a portable fence embodied in the present invention. The lower fringe portion of said fence component is cut out in a gatelike shape and is provided with legs ( 11 ) and ( 11 ) at both sides. As shown in FIG. 1, a stay pivot mount ( 12 ) to pivotably mount a stay as mentioned below is provided on the under side surface of the cut-out portion interposed between those legs ( 11 ) and ( 11 ). At the upper part of the right-and left sides ( 13 ) and ( 13 ) respectively of said fence component ( 1 ), a protrusive portion ( 13 a ) is formed while at the lower part thereof, a projected portion ( 13 b ) is formed, those portions protruding substantially to the same extent. On the under side of said portion ( 13 a ) and on the upper side of said portion ( 13 b ) respectively, a bi-axial hinge pin ( 14 ) is provided. These bi-axial hinge pins ( 14 ) are opposedly disposed to each other. A fence component ( 1 ) is made of synthetic resin (e.g., ultra high molecular polyethylene) by means of blow moulding, so that it is light in weight and excellent in shockproof. A conjunction screen foldable as shown in FIG. 5 is formed by connecting a plurality of such fence components to each other side by side. Numeral 2 indicates a stay to be mounted on the lower part of said fence component ( 1 ). This stay comprises a pair of mobile pieces ( 21 ) and ( 21 ) combined together, said pieces being identical in shape. Two holes ( 21 a ) and ( 21 a ) are bored through the respective mobile pieces to the thickness direction thereof, on one side of which a concave portion ( 21 b ) being formed in the middle of those holes to fit into a stay pivot mount ( 12 ) protrusively provided on the lower part of the fence component. As shown in FIG. 1, with said stay pivot mount ( 12 ) received into a hole formed by opposedly facing a concave portion of the respective mobile pieces ( 21 ) and ( 21 ), a bolt ( 22 ) is inserted into the respective holes ( 21 a ) and screwed with a nut ( 23 ), thereby, said stay is pivotably mounted onto the stay pivot mount ( 12 ). This makes it possible to relatively rotate said stay to the plane of the fence component. For example, as shown in FIG. 2, by the perpendicular rotation of the stay to the plane of the fence component, it allows the fence component to stably stand. A notch means being adopted for connection between the stay ( 2 ) and stay pivot mount ( 12 ), it can control and regulate the movement of the stay within an appropriate angle to the plane of the fence component. This stay is made of synthetic resin (e.g., ultra high-molecular polyethylene) like the fence component. Numeral 3 indicates a bi-axial hinge to connect the sides ( 13 ) and ( 13 ) of the adjacent fence components ( 1 ) and ( 1 ). This hinge has an oval body with two holes ( 31 ) and ( 31 ) bored therethrough. In this embodiment, as shown in FIG. 3, two bi-axial hinges are in use. The adjacent fence components are foldably connected to each other by mounting the holes ( 31 ) and ( 31 ) of the respective bi-axial hinges ( 31 ) into the bi-axial hinge pin ( 14 ) provided on the under side of the adjacent protrusive portions ( 13 a ) and ( 13 a ) respectively and into that provided on the upper side of the adjacent projected portions ( 13 b ) and ( 13 b ) respectively. With the bi-axial hinge mechanism as mentioned above, one fence component has a greater latitude of movement against the other, so that the mutual adjustment of an angle made by one plane and the other becomes easy. This bi-axial hinge is easy to detach from the vertical bi-axial hinge pin ( 14 ), so that the plurality of fence components in conjunction are free to disjoin. Biaxial hinge pins ( 14 ) extend upward from projecting portions ( 13 b ) and downward from protrusion portion ( 13 a ). Each of the biaxial hinge pins ( 14 ) has an expanded diameter portion ( 14 a ) at its end portion. The end portions are not connected to any other structure which permits the biaxial hinges ( 3 ) to be fitted onto the hinge pins ( 14 ) as shown in FIG. 3 . The pins ( 14 ) are inserted into hole ( 31 ) which are through biaxial hinge ( 3 ). As shown in FIG. 3, the inside diameter of holes ( 31 ) is smaller than the outside diameter of expanded portion ( 14 a ). This, therefore, provides for retention of the biaxial hinges ( 3 ) on the hinge pins ( 14 ), as shown in FIG. 4 . In this way, by connecting a number of fence components( 1 )·( 1 )··by means of the above-mentioned bi-axial hinges ( 3 )·( 3 ) ··, as shown in FIG. 4, a portable fence (F) foldable like a screen is obtained. FIG. 4 shows said fence comprising ten fence components, but the extensive length of the fence (F) is adjustable as desired, which is realized by varying the number of fence components to be connected. As shown in FIG. 5, the fence (F) as obtained this way is compactly folded just by sequentially overlaying the adjacent fence components one over another, so that it becomes convenient to carry and store. As for the stay ( 2 ) pivotably mounted in the cut-out portion provided on the lower part of the respective fence components, it can be contained in the cut-out portion flush to the side surfaces of the fence component, so that it does not interrupt the fence (F) from being folded as shown in FIG. 5 . Numeral 4 indicates a weight container to be placed upon the stay, which is formed of synthetic resin (e.g., ultra high-molecular polyethylene) by means of blow moulding. This container comprises a pair of hollow block pieces ( 41 ) and ( 41 ) in which a weight (W) such as water and sand can be filled; a disk-like hinge plate ( 42 ) integrally moulded on the upper part of the respective block pieces; and a connecting pin ( 43 ) to hinge those plates. As shown in FIG. 6, those block pieces open and close pivoting on this connecting pin ( 43 ). When a bridging portion ( 41 a ) formed between those block pieces is mounted onto the stay rotated perpendicularly to the plane of the fence component so as to place the weight container upon the stay with clamping both ends of the latter, the center of gravity of the fence component shifts to the downside thereof, so that it further enhances the standing stability of the fence component in addition to the rotation of the stay normal to the plane thereof. FIGS. 7 and 8 schematically show a portable fence of the present embodiment installed on the boundary of a keep-off area (S). FIG. 7 shows the portable fence installed in a linear course. In this example, the fence stands supported by the stays disposed normal to the plane surface of the respective fence components and secures its standing stability by the weight (such as water) containers placed upon the first, fourth, seventh and tenth stays counted from the left side of the drawing. Normally, a portable fence developed in a linear course is somewhat poor at standing stability, but the fence embodied in the present invention stably stands just by relatively rotating the stays to the plane surface of the respective fence components, and with the weight containers as shown in FIG. 7 placed upon the stays as desired, it further enhances its standing stability. In order to install the fence of the present invention, all the workers have to do is to carry it as compactly folded as shown in FIG. 5 to an installation site and to develop it there, so that they can carry out a series of work ranging from its storage, transportation to installation in a very efficient manner. FIG. 8 shows the fence embodied in the present invention installed in the boundary of a complicated contour, in which case too, the fence can define a keep-off area in a stable and fast manner. The preferred embodiment of the present invention has been substantially described up to here, but it is not limited to the above disclosure. It can be modified in various manners within the scope of the accompanying patent claims. For example, in the above-mentioned embodiment, though a stay ( 2 ) comprising a pair of mobile pieces ( 21 ) and ( 21 ), which interpose an stay pivot mount ( 12 ) provided on the lower part of a fence component therebetween, is pivotally mounted on said axis, it can be modified as shown in FIG. 9 such that a hole ( 15 ) is bored through the middle of the cut-out portion provided on the lower portion of a fence component, into which a pivot pin ( 24 a )( 24 ) provided at the apex of an isosceles-triangle stay is slid. Such modification naturally belongs to the technical scope of the present invention. Also, in the above-mentioned embodiment, though it is shown that the respective stays are pivotally mounted onto the lower part of the respective fence components, if desired, it does not matter whether the stays are mounted onto only one fence component or some of those fence components. This modification also belongs to the technical scope of the present invention. Further, in the above-mentioned embodiment, though it is exemplified that the adjacent components of the portable fence are connected to each other by means of bi-axial hinges, they can be arranged such that they are alternately connected to each other by means of a common hinge or some pieces of them are unremovedly hinged to each other as one unit, in which case, its commercialization is realized by adding further units as required. Such modification also belongs to the technical scope of the present invention. As having been described up to here, a portable fence embodied in the present invention is easy and fast to be installed along the boundary of a zoning area having various contours in a stable manner just by relatively rotating the respective stays pivotally mounted onto the lower part of the respective fence components to the plane surface of the latters. Upon its storage and transportation, it can save a storing space and improves the efficiency of the transportation work due to its foldability and compactness. As a plurality of the fence components is free to join and disjoin by means of bi-axial hinges, the extensive length of the fence can be adjusted as desired. Accordingly, there are a number of favorable effects brought by the portable fence embodied in the present invention, so that its industrial applicability is very high.	A portable fence is practically easy and fast to be installed along the boundary of a keep-off area to restrict and entry of the unconcerned at construction or events-holding sites and is conveniently compact to carry and store due to its foldability. This fence comprises a conjunction screen formed by connecting a plurality of fence components, preferably formed of synthetic resin by blow molding, side by side through a hinge mechanism such that they are foldable to each other and a support means or stay pivotably mounted onto a lower fringe portion of said conjunction screen, and stably provides a restricted area at a site where an access of the unconcerned is restricted in an easy and fast manner and is convenient to carry and store due to its foldability. The addition of a weight container thereto further enhances the standing stability thereof.
You are an expert at summarizing long articles. Proceed to summarize the following text: This application is a continuation of Ser. No. 07/033,554, filed Apr. 1, 1987, now abandoned. TECHNICAL FIELD The present invention deals broadly with a technology dealing with support structures. More narrowly, however, the invention covered by this document deals with support structures for mounting panels, such as those employed in creating stage backdrops, so that they can be interfitted together to complete the full backdrop. A preferred embodiment of the invention is directed to structure for facilitating movement of panels relative to other panels and for rendering them more easily and accurately interfittable. BACKGROUND OF THE INVENTION Various examples can be given of instances in which panels are supported in a general vertical orientation for one reason or another. The most readily apparent of these examples, and the primary application for which the present invention is intended, is one wherein panels are placed into position relative to one another to form a backdrop. Various types of backdrops can be formed. For dramatic productions, the backdrop would, typically, be a scenery backdrop depicting a site where action is to take place. Other types of backdrops exist, however. For example, for concerts, it might be desirable to provide one consisting of a plurality of similarly reliefed sections. In either case, however, it is important that adjacent panels be correctly aligned and that they abut one another so that corresponding lateral edges engage. In some circumstances, it might be particularly important that a plane defined by the adjacent panels be substantially vertical. These characteristics are desireable in the case of a scenery backdrop so that lines defining the scenery are not broken and out of alignment. In the case of a backdrop for a concert, alignment and common plane definition is important so that the backdrop appears to be a single, continuous panel. In the prior art, the intended results here-in-before defined were achieved in ways which left much to be desired. A typical structure for setting up backdrop panels employed a base frame which was disposed for movement over the floor of the stage or other surface. A pair of wheels, an axis between which defined a front of the base frame at which the panel was to be mounted, afforded maneuverability. The wheels were not free to pivot about any vertically extending axis. Rather, they defined generally parallel, vertically extending planes, and they rotated only about the axis of the axle to which they were mounted. The base frame afforded multiple point contact, a third, and, sometimes, a fourth point of contact being provided. These additional point or points of contact were spaced rearwardly from the front of the base frame and, in some structures, employed casters which were free to revolve 360 degrees about axes which, when the support was in position, extended generally vertically. A significant drawback to such structures was their maneuverability. While rear ends of the base frames might be able to be moved laterally, it was, typically, more important that the front ends be readily able to be moved laterally so that edges of backdrop segments could be brought into engagement. The only way this was accomplished was by moving an assembly back and forth so that it could be "worked" laterally until it was at the appropriate location. Another problem with prior art structures--and one which is probably more significant--is one occasioned by the manner in which vertical adjustment and alignment of the panels was effected. Each point of contact, had, associated an outrigger-type structure. The outriggers were spaced laterally at some distance from the point of contact, regardless of whether that point of contact comprised a wheel disposed for rotation about a horizontal axis, or a caster which was free to rotate through 360 degrees about a generally vertically extending axis. A bottom pad of each outrigger was, normally, elevated from the surface over which the support was moved, but, once the support was in an appropriate location, the outrigger pads could be lowered to engage the floor and lift the wheels or casters to positions elevated above the floor. The outriggers, thereby, served not only as leveler adjustments, but also as brakes to hold a support and its mounted panel at a desired location. While certain advantages were obtained by utilizing such a structure (for example, immobility of a panel once it was in position) serious drawbacks were experienced during the actual positioning process. The panels, after having been secured to their respective mounting towers extending upwardly from base frames of the various supports, were maneuvered so that their edges, it was intended, would abut when in proximity to one another. Forward outriggers would be lowered and lower edges of the panels substantially aligned at the same height. Thereafter, rear outriggers would be lowered to bring their pads into engagement with the floor and tilt the panels so that adjacent panels which were intended to do so, defined a common plane. In the process of adjusting the tilt of the panels, however, it frequently became necessary to maneuver a support, and, in order to do this, the outriggers had to be retracted upwardly to, again, bring the wheels and casters into engagement with the floor. Fine-tuning adjustments were then made, the outriggers, therafter, again being lowered to make final alignment manipulations. As will be able to be seen in view of this discussion, lowering and raising of the outriggers often had to have been performed repetitively. As a result, precious time was often wasted. Time economization is, however, particularly important during the staging of a play, and crew members are often severely limited in the amount of time available to make backdrop changes. It is to these problems of the prior art and desirable features dictated thereby that the present invention is directed. It is a panel support which affords not only significant maneuverability, but also ease and econo- mization of adjustability. SUMMARY OF THE INVENTION The present invention is a support structure for mounting panels which includes a base frame to which at least one panel can be mounted in a desired orientation. The base frame is supported by a plurality of caster mounting members, each member being disposed for rotation, through 360 degrees, about an axis. It is intended that the axes about which the caster mounting members rotate be substantially parallel. Each mounting member, in turn, carries a plurality of casters. The casters are disposed for revolution, through 360 degrees, about axes which are generally parallel to axes of other casters carried by a corresponding mounting member. A preferred embodiment of the invention employs, additionally, means for affording the ability to level both the front and back of the base frame. The leveling means employed is one wherein leveling of the front of the base frame, to align bottom edges of the panels carried thereby, is accomplished without, concurrently, detracting from maneuver- ability. A telescoping element is, in this embodiment, provided at a location intermediate the base frame and a caster mounting member. As leveling is accomplished, therefore, the assembly of the panel and its support can still be maneuvered. In accordance with the preferred embodiment, the telescoping elements can be made substantially coaxial with axes about which their respective caster mounting members rotate. Greater stability is, thereby, afforded. The present invention is, thus, an improved structure for supporting panels such as those used in stage backdrops, for maneuvering those panels into position relative to one another to complete a backdrop, and for adjusting one panel relative to an adjacent panel so that they form a continuity. More specific features of the invention and advantages obtained in view of those features will become apparent with reference to the DETAILED DESCRIPTION OF THE INVENTION, appended claims, and accompanying drawing figures. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a support in accordance with the present invention; FIG. 2 is a top plan view of the base frame of the support of FIG. 1; FIG. 3 is a side elevational view of the base frame of FIG. 2 with a rear outrigger in an extended position; FIG. 4 is an enlarged plan view of a caster mounting member and caster assembly as seen in FIG. 2; FIG. 5 is an enlarged elevational view of a caster mounting member and caster assembly as seen in FIG. 3; FIG. 6 is front elevational view of a caster assembly; FIG. 7 is a side elevational view of a caster assembly; FIG. 8 is a plan view taken generally along line 8--8 of FIG. 5; and FIG. 9 is a sectional view taken through a strut of the base frame. DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings wherein like reference numerals denote like elements throughout the several views, FIG. 1 illustrates a support structure 10 in accordance with the present invention, as shown with a tower frame 12, to which a face panel (not shown) can be mounted, and a maneuvering handle 14. The support structure 10 mounts on, at an end of a base frame 16 defined as the front, the tower frame 12. The tower frame 12 includes, as illustrated in FIG. 1, a pair of generally vertically extending members 18 which are interconnected, at various locations therealong by horizonal stays 20. The vertically extending members 18 are strengthened by backing pieces 22 and mounted to mating plates 24', one at the bottom of each member 18. The mating plates 24' are for the purpose of being brought into engagement, in mating relationship, with corresponding plates 24 on the base frame 16 of the support structure 10. The tower frame 12 is provided with various fittings by means of which a face panel can be held on the tower frame 12. FIG. 1 illustrates a pair of eyelets 26 secured to the tower frame 12 at the uppermost interconnecting horizontal stay 20. Additionally, other fittings 28 can be provided to more effectively secure the face panel to the tower frame 12. FIG. 1 illustrates a maneuvering handle 14 which is in the form and orientation of an inverted U. The distal end of each arm 30 of the U is provided with a plug portion 32, and corresponding female fittings 34 are provided proximate the rearward end of the base frame 16 of the support structure 10 to receive these plugs 32. When the handle 14 is mated to the support structure base frame 16, it is intended that it extends sufficiently high so that a stage hand or person moving the panels would find an interconnecting portion of the U-shaped member 14 accessible. The embodiment of the support structure 10 illustrated in the figures is shown as having a base frame 16 and three caster assemblies 36, covered by corresponding assembly cowls 38, carrying the base frame 16, the assemblies 36 functioning to provide three point contact support. The specific construction of each caster assembly 36 will be discussed here-in-after. The base frame 16 of the support 10, in the embodiment illustrated, defines a generally trapezoidal-shaped frame. The perimeter of the frame is formed from stock generally C-shaped in cross-section. FIG. 9 illustrates, in section, the type of stock which, it is envisioned, would be employed. An open end of the C would face inwardly toward the interior of the defined trapezoidal-shaped structure. By so constructing the base frame 16, in part, it can be afforded strength sufficient to accomodate the backdrop panel and other elements carried thereby. As previously discussed, an open end of the trapezoidal-shaped structure defines what forms the front of the support structure 10 in that a panel would extend along an axis defined by this open end of the structure and, when properly in position, obscure the bulk of the support structure 10 behind the panel. Because such panels tend to be large and, often, heavy, the center of gravity of a support structure 10 having a panel mounted thereto would be shifted toward the front of the overall assembly. Consequently, as the center of gravity approaches the front edge, the assembly could become quite unstable. As a result, a counter-weight box 40 having one or more counter-weights (not shown) carried therein can be provided near the rear of the assembly. The weight and number of the counter-weights can be varied depending upon the size and weight of the panel being carried by the support structure 10. The figures, as previously discussed, illustrate a support structure 10 employing three caster assemblies 36. In order to afford a height adjustment and leveling feature, a telescoping element 42, 44, associated with each caster assembly 36, can be provided. FIGS. 1, 2, and 3 illustrate the location of the outrigger telescoping member 44 associated with the rear caster assembly. This outrigger 44 is, as shown in the figures, mounted in an appropriate manner (such as welding) to an outwardly facing surface of the C-shaped member substantially centrally along the portion of the C-shaped member defining the rear of the support structure 10. The rear caster assembly outrigger includes inner and outer housings 46, 48 that telescope relative to one another. The outer housing 48 is secured to the C-shaped member, and the inner housing 46 is disposed for reciprocal movement downwardly relative thereto. It carries a pad 50 at a lower end thereof for engagement with the floor on which the support structure 10 is situated. The length of the inner housing 46 is such that, when it is at its lowermost position, it extends downwardly beyond lower extremities of the caster wheels 52 of the rear caster assembly 36. Consequently, the rear caster assembly 36 can be elevated relative to the floor. The rear outrigger 44 effects elevation of the base frame 16, at the rear end thereof, by means of a threaded shaft 54 disposed at a fixed axial location relative to the outer housing 48. This can be accomplished by mounting stops 56, 58 to the shaft 54, proximate the upper end thereof, to sandwich a plate 60 closing the upper end of the outer housing 48. The stops 56, 58 can take the form of nuts which are pinned to the shaft 54. A lower end of the shaft 54 can include a stop 62 (again, a nut either pinned or welded to the shaft 54) which engages an underside of a wall 64 of the inner housing 46 to preclude separation of the inner and outer housings 46, 48 from one another. The upper wall 64 of the inner housing 46 can have an internally threaded aperture 66 provided therein so that, as the shaft 54 is rotated, the inner housing 46 will move axially relative to the outer housing 48. Each of the front caster assemblies 36, similarly, includes an inner/outer housing leveler assembly. In the case of the front caster assemblies, however, the inner/outer housing height adjustment mechanism is interposed between the caster assembly 36 and the C-shaped member. Consequently, the base frame 16, at its front end, can be adjusted for height without the caster wheels 52 of those front caster assemblies 36 being elevated above the floor. The height adjustment assemblies are similar in construction to that of the rear leveler outrigger 44. That is, they include inner and outer housings 46, 48 which are selectively adjustable along an axis relative to one another. A threaded shaft 54, fixed axially, yet rotatable, with respect to an upper wall 60 of the outer housing 48 is made to rotate within a threaded aperture 66 in an upper wall 64 of the inner housing 46. As rotation is accomplished, the inner housing 46 will be drawn into, or extended relative to, the outer housing 48, depending upon the direction of rotation of the shaft 54. The forward caster assemblies 36 will now be described specifically with reference to FIGS. 4 and 5. A forwardly extending end of the C-shaped member is welded or secured to the underside of the plate 24 by which the tower frame 12 is mated to the base frame 16. An upper end of one of the front leveler assemblies is, in turn, welded to an innerface of the C-shaped member and to the underside of the mating plate 24, and a strengthening brace 68 can be provided. As seen in FIG. 4, an arcuate portion 70 of the mating plate 24 is cut out. By so doing, an appropriate relationship of the parts can be provided without access to a head of the threaded shaft 54 being obstructed. The caster assembly comprises three caster wheels 52. Each wheel 52 is journalled between a pair of flanges 72 depending downwardly from an attachment plate 74. Journalling of the caster wheels 52 can be accomplished in any appropriate manner. The figures illustrate employment of nuts 75 which are secured onto threaded portions of axles 76 extending through the wheels 52. Appropriate bearings (not shown) can be employed to insure the ability of the caster wheels 52 to freewheel. Each caster wheel 52 is associated with a swivel cup 80. Such a cup 80 houses bearings (not shown) or other appropriate means for permitting revolution of a corresponding caster wheel 52, through 360 degrees, about a generally vertically extending axis. The swivel 80 allows rotation relative to the attachment plate 74 with which it is associated. The attachment plates 74 associated with the three caster wheels 52 of a particular caster assembly 36 are, in turn, secured to a caster mounting member 82 such as the truncated triangular plate illustrated in the figures. This securing is accomplished in any appropriate manner (for example, by a nut and bolt arrangement 84). Each caster assembly 36, in turn, is associated with another swivel 86, the swivel 86 being disposed relative to an axis coinciding with a central axis of the caster mounting member 82. Again, a cup-like element is secured to a plate 88 with respect to which it rotates, and that plate 88 is, in turn, mated to another similarly sized and shaped plate 90 (rectangular as shown in the figures). Again, a nut/bolt arrangement can be employed for mating, and the upper plate 90 can be provided with elongated holes 92 to facilitate mating. The upper mating plate 90 is secured, for example, by welding to the bottom of the inner housing 46 of the height adjustment assembly. As will be able to be seen in view of this disclosure, not only is each individual caster wheel 52 able to be revolved about a generally vertically extending axis, but the caster assembly 36 of which it is apart is also able to be rotated about a generally vertically extending axis. Consequently, maneuverability of the support structure 10 is maximized not only in a single direction, but in virtually any direction. When utilizing the present invention, as described herein, to form a backdrop, for example, the tower frame 12 is secured to the support structure 10 by appropriate means as previously described. A face panel is, in turn, secured to the tower frame 12. Either prior to, concurrently with, or immediately after, affixation of a face panel, the appropriate counter-weight of counter-weights are placed in the counter-weight box 40. With the assembly thus configured, it is ready to be maneuvered so that the face panel carried thereby can be mated in an abutting relationship to another panel. Mating is accomplished by maneuvering support strucures 10 into positions wherein panels carried thereby are generally at locations relative to other panels as intended. Lower edges of the various panels are aligned by manipulation of the various leveler assemblies at the fronts of the support structures 10. The lower edges are aligned at a desired height such that concealing of what is behind the panels is maximized. With the lower edges of the panels aligned and leveled, the panels can be made coplanar by adjusting the rear outrigger 44. As an outrigger 44 is adjusted, its pad 50 engages the floor to function as a brake and preclude significant movement of the support structure 10 and the panel mounted thereon. As the rear end of a support structure 10 is raised to tilt the panel forwardly, the lower edge of the panel being tilted may rise slightly. It would, therefore, become necessary to again adjust the forward height-adjustment/leveler assemblies. These adjustments would, of course, be "fine tuning" of positions. Additionally, it might be necessary to adjust the lateral positioning of one panel relative to another. This can, of course, be easily accomplished because of the caster and caster mounting member arrangement as defined herein. Numerous characteristics and advantages of the invention of this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts without exceeding the scope of the invention. The invention's scope is, of course, defined in the language in which the appended claims are expressed.	A support structure for mounting and rollably supporting stage backdrop panels and the like is disclosed. A base frame includes a plurality of caster mounting members, with each mounting member rotatable relative to the base frame about an individual mounting member axis. A plurality of casters are rotatably carried by each mounting member, each caster being offset from the axis of its respective mounting member. Several of the mounting members can be attached to the base frame by telescoping fittings, allowing the height of the base frame to be adjusted without disengaging the casters from rollable engagement with the stage floor.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION [0001] This disclosure relates to joints for drill tubes, and in particular threaded joints for thin-walled drill tubes. BACKGROUND [0002] A joint for a drill tube transfers the torque power from one tube part to another. Because of a thinner wall thickness, the joint is generally weaker than the rest of the tube. At a certain drilling depth, the tube gets so long that the weight becomes greater than the desired drilling thrust. To keep the desired drilling thrust at the drill bit end of the tube, an increased pullback tension load is required at the opposite end of the drill tube. Therefore, when drilling deep, the joint needs a high tension load capacity. [0003] A threaded joint may be modified to make it stronger. One such solution is presented in U.S. Pat. No. 5,788,401, wherein a thin walled drill tube joint with a negative thread pressure flank is disclosed. The problem is solved with a negative pressure flank of 7.5° to 15° relative to a direction perpendicular to the central axis to provide for lower stress states. Further, the threaded section of the joint tapers along the axial length of the joint, with kept thread depth. A problem with this solution is that such tube joint is difficult to manufacture. [0004] Hence, there is a need for an improved drill tube joint. SUMMARY OF THE INVENTION [0005] It is an object of the present invention to provide an improved joint for a thin-walled drill tube. One particular object is to provide a joint that is strong yet easy to manufacture. The joint comprises a male part and a female part, which are connectable to each other by a thread connection. [0006] According to a first aspect, a member of a joint in a thin-walled drill tube is provided, presenting a central axis and comprising a thread for forming a screw joint, wherein the thread presents a thread bottom, a thread top, a pressure flank and a clearance flank, characterized in that the pressure flank presents a portion having a negative angle less than 7.5°, but larger than 0°, relative to a direction perpendicular to the central axis. [0007] When discussing angles of flanks and thread tops, it is understood that it is the main angle of the respective surface that is intended, and that any radii at edges of the respective surface should be disregarded. [0008] The strength of the joint depends partly on the wall thickness of the joint parts. A shallow thread depth enables a greater wall thickness of the joint parts. With such solution, the thread depth may be reduced and the wall thickness increased, providing a stronger joint for deeper drilling. A tensile increase from 424000 N to 479000 is possible, which translates into about 300 m further drilling. [0009] A negative angle is defined as an angle creating an undercut flank surface. By thin-walled drill tube, it is meant a tube with a wall thickness, excluding the thread, of about 3 to 6.4 mm, about 3 to 5.6 mm, or about 3 to 4.2 mm. [0010] In further embodiments, the negative angle of the pressure flank portion may be about 1° to 6°, about 2° to 5°, about 4° to 5°, or about 5° relative to the direction perpendicular to the central axis. [0011] In order to enable a reduced thread depth for increased wall thickness, the material of the member must be strong enough to manage the increased tension load on the thread due to reduced depth. One embodiment presents a joint member made of substantially through-hardened steel. When the steel is through-hardened and not only surface-hardened, no heat affected zone that can cause breakage of the thread top is created. [0012] The thread depth, defined as the radial distance between the thread bottom and the thread top, can, in further embodiments, be about 0.5 to 0.8 mm, about 0.5 to 0.7 mm, or about 0.5 to 0.6 mm. [0013] To enable more efficient use of the thread depth for more effective power transmission and better tension load capacity, in one embodiment, the material thickness at least one of the thread bottom and the thread top may taper towards an end portion of the member. This means that the thread depth is not constant along the surface of the member over which the thread extends. This solution may, when the male member is connected to a female member, result in a tapering clearance between the male and female members. A further advantage with this effect is that more space is offered for dirt and grease between the threads, which otherwise could cause disturbances and reduced tension load capacity in the connection. [0014] In a further embodiment, the thread bottom may be substantially parallel with the central axis and the material thickness of the thread top tapers towards the end portion of the member. [0015] The clearance flank of the thread may in one embodiment present a portion with an angle less than 45° relative to the direction perpendicular to the central axis. [0016] In a further embodiment, the clearance flank of the thread may present a portion with an angle that is different at different sections of the thread. A rather large angle on a first thread section located close to the end portion of the member may facilitate the assembly of the male member with a female member. The clearance flank may then in one embodiment present a portion with an angle of about 10° to 40°, about 20° to 35°, or about 30° relative to the direction perpendicular to the central axis. [0017] The first thread section may be located closer to an end portion of the member than a second thread section. The second section may present a clearance flank portion with an angle of about 0° to 15°, about 1° to 10°, or about 5° relative to the direction perpendicular to the central axis. The clearance flank angles of the different thread sections may be combined in different embodiments according to Table 1. X indicates explicit disclosure of a first and second section clearance flank angle combination. [0000] TABLE 1 0° to 15° 1° to 10° 5° 10° to 40° x x x 20° to 35° x x x 30° x x x [0018] A thread pitch of the member may be about 0.8 to 1.6 threads per centimeter, about 0.8 to 1.2 threads per centimeter, or about 1 thread per centimeter. [0019] At least one of the pressure flank and the clearance flank may be connected to the thread bottom via a radius of more than about 0.10 mm or more than about 0.15 mm. [0020] At least one of the pressure flank and the clearance flank may be connected to the thread top via a radius of more than about 0.10 mm or more than about 0.15 mm or more than about 0.20 mm. [0021] The member may be a male member, wherein the thread extends along an outer portion of the member. In the alternative, the member may be a female member, wherein the thread extends along an inner portion of the member. [0022] The female member presents in different embodiments substantially the same features as the male member. The two members may have the same pressure flank and clearance flank angles, thread depth and material. [0023] In one embodiment, the thread top may, for a male member, taper with an angle of about 0.2° to 0.6°, about 0.3° to 0.5°, about 0.3° to 0.4°, or about 0.34° relative the central axis. In another embodiment, the material thickness of the thread top may, for a male member, taper with an angle of about 1.7° to 2.5°, or about 2° to 2.5° relative the central axis. [0024] In one embodiment, the material thickness of the thread top may, for a female member taper with an angle of about 0.2° to 0.6°, about 0.2° to 0.4°, about 0.2° to 0.3°, or about 0.28° relative to the central axis. At the same time the thread bottom may be substantially parallel with the central axis. [0025] A second aspect provides a joint system for a drill tube comprising a male member and a female member according to any of the previous presented embodiments. The joint system may, in one embodiment, present a tapering clearance between a thread top of one of the members and a thread bottom of the other one of the members. This feature presents the effect that a maximum part of the thread depth is used when the pressure flanks of the two members are in connection. It also allows more space for dirt and grease in the thread connection. In practice, the thread depth may vary and/or the material thickness at the thread bottom may vary. [0026] In a further embodiment of the invention the tapering clearance is present over at least two juxtaposed threads. With as much connection surface as possible between the pressure flanks of the two members as possible, the more the thread depth can be reduced, enabling increased wall thickness, with kept tension load capacity of the joint. Therefore it is an advantage if all threads have a tapering clearance at the connection between the two members. [0027] According to a third aspect, there is provided a thin-walled tube drill system, comprising a joint system as described above, wherein the male member is arranged on a first thin-walled drill tube and the female member is arranged on a second thin-walled drill tube. [0028] According to a fourth aspect, there is provided a male or female member of a joint for a drill tube, presenting a central axis and comprising a thread for forming a screw joint, wherein the thread presents a thread bottom, a thread top, a pressure flank and a clearance flank, wherein a material thickness at least one of the thread bottom and the thread top tapers towards an end portion of the member. [0029] According to a fifth aspect, there is provided a male or female member of a joint for a drill tube, presenting a central axis and comprising a thread for forming a screw joint, wherein the thread presents a thread bottom, a thread top, a pressure flank and a clearance flank, at least one of the pressure flank and the clearance flank is connected to the thread bottom via a radius of about 0.15 mm. [0030] According to a sixth aspect, there is provided a male or female member of a joint for a drill tube, presenting a central axis and comprising a thread for forming a screw joint, wherein the thread presents a thread bottom, a thread top, a pressure flank and a clearance flank, at least one of the pressure flank and the clearance flank is connected to the thread top via a radius of about 0.20 mm. [0031] It is understood that each of the fourth to sixth aspects may be used in combination with any embodiment under the first or second aspects, or independently thereof. BRIEF DESCRIPTION OF THE DRAWINGS [0032] In the following, an embodiment will be described in more detail with reference to the accompanying drawings. [0033] FIG. 1 a is a perspective cross-sectional view of a male member. [0034] FIG. 1 b is a cross-sectional view of a male member. [0035] FIG. 2 is a cross-sectional view of one half of the joint with a male member and a female member. [0036] FIG. 3 is a cross-sectional detail view of the connection between a male and female member thread. DETAILED DESCRIPTION [0037] With reference to FIGS. 1 a and 1 b , a male member 1 of a joint for a drill tube is shown. The inner diameter 30 of the tubular tube and joint, as well as the outer diameter 31 , may be specified for an industrial standard. A base portion 2 of the cylindrical member has the same outer diameter 31 as the drill tube, and a base shoulder 3 connects the base portion 2 with the outer portion of the member that is provided with a thread 4 . The thread extends along the axial length of the member 1 , and ends at an end portion 5 . [0038] The thread 4 presents a thread bottom 6 , a thread top 7 , a pressure flank 8 and a clearance flank 9 . The thread bottom 6 is defined as the part of the thread with the shortest radial distance from the central axis A. The part with longer radial distance from the central axis is the thread top 7 . The greatest radial distance between the thread bottom 6 and the thread top 7 defines the thread depth 32 . An inner cylindrical surface 10 of the member 1 defines, together with the thread bottom 6 , the wall 11 of the member 1 . [0039] The base shoulder 3 is undercut and tapers towards the threaded portion of the member with an angle 20 of about 15° relative to a direction perpendicular to the central axis A. The pressure flank 8 is the flank of the thread 4 facing the base portion 2 . The pressure flank 8 has an undercut surface with a negative angle 21 of about 5° relative to a direction perpendicular to the central axis A. The clearance flank 9 faces towards the end portion 5 . The clearance flank 9 may have different angles at different sections of the thread 4 . A first section 15 of the thread is provided closest to the end portion 5 of the member. That first section 15 may present an entrance clearance flank 12 with a positive angle 22 of about 30° relative to a direction perpendicular to the central axis A. In a second section 16 of the thread, the clearance flank 9 may present a positive angle 23 of about 5° relative to a direction perpendicular to the central axis A. A larger angle in the first thread section 15 may facilitate the assembly of the male member 1 into a female member in a joint, and reduces the risk of damaging of the threads. [0040] The member 1 and the member end portion 5 , terminate at an end shoulder 13 . The end shoulder 13 tapers with a negative angle 24 of about 15° relative to a direction perpendicular to the central axis A. The end shoulder is connected to the inner cylindrical surface 10 of the member via a chamfer 14 with an angle 25 of about 15° relative the central axis A. [0041] The thread bottom 6 may be substantially parallel with the central axis A. The thread top 7 tapers towards the end portion 5 of the male member 1 with an angle 26 of about 0.34° relative the central axis A. This results in a non-constant thread thickness 32 . To increase the strength in the joint, it is desirable to make the wall 11 as thick as possible, and therefore it is desirable to make the thread thickness 32 as shallow as possible. In this embodiment of the invention, the thread depth 32 may be about 0.5 to 0.7 mm. [0042] The pressure flank 8 presents the angle 21 . The pressure flank 8 is connected to the thread top 7 via a radius 40 , which may be about 0.2 mm. The pressure flank is further connected to the thread bottom 6 via a radius 41 , which may be about 0.15 mm. In the same way, the clearance flank 9 of the second thread section 16 may be connected to the thread top 7 via a radius 42 , which may be about 0.2 mm, and connected to the thread bottom 6 via a radius 43 , which may be about 0.15 mm. The entrance clearance flank 12 is connected to the end portion 5 via a radius 44 , which may be about 0.4 mm. The different radii at the flanks have the effect that the loads on the connections are distributed over a larger area. The sizes of the radii may be adjusted for optimal effect. The radii also make it easier to achieve a tight connection surface between the flanks. [0043] The joint system according to the invention comprises a male member 1 and a female member 101 , wherein the male member comprises a thread extending along an outer portion of the member, and the female member 101 comprises a thread extending along an inner surface portion of the member. FIG. 2 shows the male member 1 in joint connection with the female member 101 . The female member 101 presents corresponding parts as the male member 1 including a base portion 102 , an end portion 103 , a base shoulder 104 , an end shoulder 105 and a threaded portion presenting a thread bottom 106 , a thread top 107 , a pressure flank 108 , a clearance flank 109 and radii. The base shoulder 104 tapers towards the threaded portion of the female member 101 with a negative angle of about 15° relative to a direction perpendicular to the central axis A. The base shoulder 104 is connected to the jacket surface of the base portion 102 via a chamfer 110 of about 15° relative to the central axis A. The end portion 103 terminates at the end shoulder 105 that tapers with a negative angle of about 15° relative to a direction perpendicular to the central axis A, and is connected to an outer surface 111 of the female member. The pressure flank 108 and the clearance flank 109 , present the same positive and negative angles as the corresponding angles for the male member 1 . [0044] The thread bottom 106 of the female member 101 may be substantially parallel with the central axis A, providing a constant wall thickness of the female member wall 112 . The thread top 107 may taper towards the female member end portion 103 with an angle 120 of about 0.28° relative the central axis A. Therefore, the thread depth at the thread part axially closer to the base portion of each member may differ from the thread depth at the thread part axially closer to the end portion of each member. [0045] The thread pitch of the male member 1 and the female member 101 respectively may be about 2.5 threads per inch. [0046] In the joint connection between the male member 1 and the female member 101 , the pressure flanks 8 , 108 of the two members are in connection and provide the tension load capacity of the joint. The difference between the angles 26 and 120 of the two thread tops 7 and 107 and the two thread bottoms 6 and 106 creates, as seen in FIG. 3 , tapering clearances 201 , 202 between the female thread bottom 106 and the male thread top 7 , and between the female thread top 107 and the male thread bottom 6 . The thread bottoms 6 , 106 may be substantially parallel with the central axis A. This feature provides a good and effective connection surface between the pressure flanks 8 and 108 . Also, the radii 40 , 41 connected to the pressure flanks help providing a more efficient connection surface. The tapering clearances 201 , 202 , together with the clearance 203 between the clearance flanks 9 , 109 , create space for grease and dirt in the thread. This has the positive effect that interference of grease and dirt on the pressure flank connection is reduced. [0047] To enable the solution in this embodiment, with reduced thread depth and increased wall 11 , 112 thickness, the material of the walls 11 , 112 and the threads may be of through-hardened steel. With a material that is not through-hardened, for instance surface-hardened, there is a risk of weaker threads due to heat effected zones.	A member of a joint for a thin-walled drill tube presents a central axis and comprises a thread for forming a screw joint. The thread presents a thread bottom, a thread top, a pressure flank and a clearance flank. The pressure flank presents a portion having a negative angle less than 7.5°, but at least 0°, relative to a direction perpendicular to the central axis.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE PRESENT INVENTION [0001] 1. Field of Invention [0002] The present invention relates to a display box, and more particularly to a display box which has an easy-to-reach compartment, allowing the storage and safe-keeping of important documents, such as warranty certificate and user manual, such that such documents will not be easily lost when the item on display is being displayed. [0003] 2. Description of Related Arts [0004] Display boxes have always played a very important role in the sales of jewelry and other accessories such as watches. The primary function they serve is to hold a display piece such as jewelry or watch at a time to nicely display the jewelry or watch to potential buyers. They help protecting a display piece from being damaged by other display pieces when many of such display pieces are being displayed at the same time. [0005] They also enhance the presentation of the display piece than the display piece itself can offer. Without display boxes, any piece of jewelry would not look as classy or desirable than they should. Unfortunately, these two functions are pretty much what conventional display boxes could offer. [0006] People who have done jewelry shopping, such as necklaces, bracelets, watches and so forth, must have seen sales persons struggling to free the piece of display piece from the display box when the shopper wished to take a full look of the piece of jewelry, or the sales persons simply are not allowed to detach the display piece from the display box for security reasons, such that the shopper has to look at the piece of item with the display box attached, turning the box around ridiculously together with the display piece therein, and not being able to take a good look of the display piece. [0007] When the shoppers finally do purchase the piece of jewelry, they must also have seen the sales person either reaching somewhere else, such as a drawer in the store, for important documents such as the warranty certificate and/or the user manual, or, trying very hard to open up the display layer of the box to reach the documents that are well-hidden and yet difficult-to-reach. [0008] Furthermore, even the piece of jewelry is purchased with the display box, after a certain period of time, the documents would be lost and no where to be found, simply because of the fact that the conventional display boxes do not offer a good protection to such important documents. [0009] In view of the above drawbacks of and the problems brought on by conventional display boxes, a better display box has to be provided so as to not only provide a protection to the display piece placed therein, better security of and convenience to reach the display piece, but also provide secured and easy-to-reach storage of important documents. SUMMARY OF THE PRESENT INVENTION [0010] A main object of the present invention is to provide a display box for displaying a display piece, comprising a box body having a receiving compartment, a base cover to enclose the receiving compartment, and a display arrangement comprises a display stand, and a folding panel, wherein the display stand pivots between a display position and an accessing position to allow access of the display piece and a hidden cavity. [0011] Another object of the present invention is to provide a display box, wherein the hidden cavity is provided for the safe-keeping of documents, such as the warranty certificate or user manual of the display piece. [0012] Another object of the present invention is to provide a display box allowing important documents of the display piece being stored together with the display piece, avoiding mixing up of important documents of other jewelry items, or loosing of the important document. [0013] Another object of the present invention is to provide a display box, wherein when the folding panel is in the display position, the display piece cannot be taken out therefrom and the hidden cavity is inaccessible, such that both the display piece and the document within the hidden cavity are both securely and safely stored. [0014] Another object of the present invention is to provide a display box, wherein the display stand is flexible, such that the display box is capable of displaying display pieces of different nature, size and shape. [0015] Another object of the present invention is to provide a display box which not only allows the display piece and the documents to be safely stored but also easy to be accessed such that the display piece and the document can be taken out simply by pivoting the display panel from the display position to the accessing position. [0016] Another object of the present invention is to provide a display box, wherein forced is required to pivot the display panel from the display position to the accessing position, such that the box cover will not accidentally open up during handling or transportation. [0017] Another object of the present invention is to provide a display box, further comprises a locking unit, such that display piece can be secured on the display stand, so as to prevent the display piece from being taken out from the display box in an unauthorized manner. [0018] Another object of the present invention is to provide a display box, wherein the locking unit is hidden when the folding panel is in the display position, such that it is inaccessible and hence effectively prevents the display piece from being taken in an unauthorized manner, and is easily accessible when the box cover is in the opened position. [0019] Accordingly, in order to accomplish the above objects, the present invention provides a display box for storing and displaying a display piece, comprising: [0020] a box body having a receiving compartment; [0021] a box cover covering on the box body to enclose the receiving compartment; and [0022] a display arrangement, which comprises: [0023] a display stand adapted for detachably holding the display piece in position; and [0024] a folding panel having a mounting edge extended from the display stand and a pivot edge pivotally connecting to a surrounding wall of the box body to form a hidden cavity within the receiving compartment at a position underneath the folding panel such that the display stand is adapted to fold between a display position and an accessing position, wherein at the display position, the folding panel is pivotally folded within the receiving compartment to enclose the hidden cavity so as to retain the display stand within the receiving compartment for securely holding the display piece in the box body, and at the accessing position, the folding panel is pivotally folded to lift up the display stand from the receiving compartment to expose the hidden cavity such that the display stand is allowed for the display piece detaching therefrom. [0025] These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0026] FIG. 1 is a prospective view of a display box according to the preferred embodiment of the present invention. [0027] FIG. 2 illustrates the box cover and the box body according to the above preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0028] Referring to FIG. 1 and FIG. 2 of the drawings, a display box for displaying a display piece according to a preferred embodiment of the present invention is illustrated, wherein the display box comprises a box body 10 , and a box cover 20 , and a display arrangement 30 . [0029] The box body 10 has a receiving compartment 11 and a surrounding wall 12 . The box cover 20 is provided for covering the box body 10 to enclose the receiving compartment 11 . [0030] The display arrangement 30 comprises a display stand 31 and a folding panel 32 , wherein the display stand 31 is adapted for detachably holding the display piece 5 in position. The folding panel 32 has a mounting edge 321 and a pivot edge 322 . [0031] The mounting edge 321 of the folding panel 32 extends from the display stand 31 , while the pivot edge 322 is pivotally connected to the surrounding wall 12 of the box body 10 . The positions of the mounting edge 321 and the pivot edge 322 effectively creates a hidden cavity 13 within the receiving compartment 11 at a position underneath the folding panel 32 . [0032] Essentially, the display stand 31 is adapted to fold between a display position and an accessing position, such that the display piece 5 is safely in place when the display stand 31 is in the display position, and can be taken out from the display stand 31 when the display stand 31 is in the accessing position. [0033] While the display stand 31 is in the display position, the folding panel 32 is pivotally folded within the receiving compartment 11 to enclose the hidden cavity 13 . As a result, the display stand 31 is retained within the receiving compartment 11 for securely holding the display piece 5 in the box body 10 . [0034] The hidden cavity 13 is also complete hidden from the viewers or users when the display stand 31 is in the display position. It is worth mentioning that the hidden cavity 13 is completely shielded from the users or viewers. Without moving the display stand 31 from the display position into the accessing position, presence of the hidden cavity 13 is completely undetectable. [0035] And when the display stand 31 is at the accessing position, the folding panel 32 is pivotally folded to lift up the display stand 31 from the receiving compartment 11 to expose the hidden cavity 13 , such that the display stand 31 is allowed for the display piece 5 to be detached from the display stand 31 for examination or better viewing. And since the hidden cavity 13 is now enclosed, any materials placed within the hidden cavity 13 can now be accessed or taken out of the hidden cavity 13 . [0036] As a result, a second item 9 such as important document like warranty certificate or messages will be safely protected within the hidden cavity 13 . The second item 9 will not fall off from the display box such that they will not be easily lost during transportation, or through mishandling of the display box. Also, the display piece 5 is also well protected by the display box. [0037] Moreover, despite the fact that the second item 9 is well protected within the lost 13 when the display stand 31 is in the display position, the second item 9 can be easily accessed when desired. [0038] Unlike conventional display boxes where either no such hidden cavities are available or accessing of the compartments requires difficult pulling apart of the display box when documents are stored in such compartments, all that has to be done to access the second item 9 stored within the hidden cavity 13 is to pivot the display stand 31 from the display position to the accessing position. [0039] The display stand 31 is substantially mounted to the folding panel 32 to define a bottom disposing portion 323 below the folding panel 32 and an upper exposing portion 324 above the folding panel 32 such that when the folding panel 32 is pivotally folded to the receiving compartment 11 at the display position, the hidden cavity 13 is enclosedly formed within the bottom disposing portion 323 of the display stand 31 , the corresponding surrounding wall 12 of the box body 10 , a bottom wall 14 of the box body and the folding panel 32 . [0040] The display arrangement 30 further has a partition wall 33 extended from the box body 10 to partition the receiving compartment 11 into the hidden cavity 13 at a position underneath the folding panel 32 such that the folding panel 32 forms an enclosing cover 325 to enclose the hidden cavity 13 when the folding panel 32 is pivotally folded on the partition wall 33 . [0041] The hidden cavity 13 is provided for accommodating a second item 6 therewithin, such that the second item, such as a certificate of warranty can be bounded within the hidden cavity 13 , by the box body 10 , the corresponding surrounding wall 12 , the enclosing cover 325 and the partition wall 33 . When the second item 6 is placed within the hidden cavity 13 , the second item 6 is well protected such that the second item 6 will not fall off from the display box, be taken out of the display box in an unauthorized manner or be easily reached by external objects. However, the second item 6 can also be reached when required. [0042] It is worth mentioning that the partition wall 33 has a predetermined height and a top supporting edge 331 provided for substantially supporting the folding panel 32 when the folding panel 32 is pivotally folded to enclose the hidden cavity 13 . [0043] The display box further has a locking unit 40 provide for locking the display piece 5 at the display stand 31 . The locking unit 40 comprises a locking ring 41 and a breakable locking loop 42 . [0044] The locking ring 41 is mounted between the mounting edge 321 of the folding panel 32 and the disposing portion 323 of the display stand 31 . The breakable locking loop 42 encircles the disposing portion 323 of the display stand with the locking ring 41 for typing up the display piece 5 with the display stand 31 . [0045] The reason is that when the folding panel 32 is pivotally folded at the display position, the locking unit 40 is hidden within the receiving compartment for preventing the locking loop 42 to be accessed. And, when the folding panel 32 is pivotally folded at the accessing position, the locking loop is exposed from the receiving compartment, so as to allow the locking loop 42 to be broken for unlocking the display piece 5 with the display stand 31 . [0046] The function of the locking unit 40 , as can be seen, is to lock the display piece 5 with the display stand 31 . It provides protection for the display piece 5 placed within the display box, such that unauthorized persons cannot easily detach the display piece 5 from the display box. [0047] Furthermore, the partition wall 33 further has a guiding slot 332 . The guiding slot 332 is indently extended from the top supporting edge 331 of the guiding slot 332 so as to alignedly receive the locking ring 41 in the guiding slot 332 when the folding panel 32 is pivotally folded on the partition wall 33 . [0048] The guiding slot 332 is provided for ensuring that the display stand 31 and the folding panel 32 can open and close matchingly, so as to concealedly close the hidden cavity 13 , for protecting both the display piece 5 and the second item 6 . [0049] The box body 10 further has a side platform 14 , which is shaped and sized symmetrical to the folding panel 32 . The side platform 14 is also sidewardly extended from an opposed surrounding wall 15 within the receiving compartment 11 to form a central channel 16 between the side platform 14 and the folding panel 32 so as to receive the display stand 31 in the central channel 16 when the folding panel 32 is folded to enclose the hidden cavity 13 . [0050] As a result, the display piece 5 , when placed on the display stand, is essentially within the central channel, such that the display piece 5 is in between the folding panel 32 and the side platform 14 providing a protection to the display piece 5 . [0051] The display box further has a retention unit 50 for retaining the folding panel 32 at the display position. The retention unit 50 has a retention groove 51 and a retention arm 52 . [0052] The retention groove 51 is indently formed on an inner wall 131 of the hidden cavity 13 and the retention arm 52 has a hooking tip 521 downwardly extended from the folding panel 32 and arranged when the folding panel 32 is pivotally folded to enclose the hidden cavity 13 . [0053] The hooking tip 521 of the retention arm 52 is then engaged with the retention groove 51 to substantially retain the folding panel 32 in position, which in turn would retain the display piece 5 in a display position, to enhance the presentation of the display piece 5 . [0054] And, some force has to be applied to the folding panel 32 to lift the display stand 31 upwards, such that the hocking tip 521 of the retention arm 52 is essentially pulled away from the retention groove 51 on the inner wall 131 of the hidden cavity 13 of the box body 10 , such that the folding panel 32 is free to pivot from the display position to the accessing position. [0055] Hence, it can be seen that the retention unit 50 helps preventing the folding panel 32 from accidentally pivoting into the accessing position, such that the second item 9 is well protected within. [0056] It is worth mentioning that according to the preferred embodiment of the present invention, the pivot edge 322 of the folding panel 32 is pivotally connected to the box body 10 via a pivot joint 326 . [0057] The pivot joint 326 comprises a first joint member 3261 and a second member 3262 . The first joint member 3261 is substantially mounted on the surrounding wall 12 of the box body 10 . [0058] The second member 3262 is substantially mounted on a bottom side 327 of the folding panel 32 at the pivot edge 322 to pivotally connect to the first joint member 3261 such that when the folding panel 32 is pivotally folded at the display position to enclose the hidden cavity 13 , the pivot joint 326 is invisibly hidden within the hidden cavity 13 . [0059] One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. [0060] It will thus be seen that the objects of the present invention have been fully and effectively accomplished. It embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.	A display box for displaying a display piece, comprising a box body, a box cover and a display arrangement comprises a display stand, and a folding panel. A hidden cavity is formed by a mounting edge, a pivot edge and a surrounding wall of the box body is allowing the storage and safe-keeping of important documents, such that they will not be easily lost when the display piece is being displayed. The hidden cavity is also simply accessed, such that the important documents are stored safely yet easy to reach. A hidden, yet simply accessed, locking unit is also provided for locking the display piece to the display box, so as to prevent the display piece from being taken out of the display box in an unauthorized manner.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION [0001] The invention is directed toward the field of suspended ceiling systems, particularly to torsion spring attachment systems, and more particularly to a clip and frame assembly for torsion spring attachment. BACKGROUND OF THE INVENTION [0002] Suspended acoustical ceiling systems are frequently used to mask functional systems such as plumbing, electrical wiring, telecommunications wiring and the like. There are two basic types of suspended acoustical ceiling systems: lay-in panel systems, in which the ceiling tiles are lifted into and rest on a metal grid suspension system with no physical attachment; and frame panel systems in which each of the tiles is surrounded by a rigid frame that is, in turn, connected securely to a metal grid. [0003] FIG. 1 depicts a typical suspended ceiling system 100 of the frame panel type comprising plurality of ceiling panels 102 that are supported by and removably attached to a suspended grid 104 . Torsion springs 112 are attached to each panel 102 and provide a removable means for holding the panel securely against a foot portion 104 a of the grid 104 . As illustrated in FIG. 1 , one panel, panel 102 a, is depicted in an open and partially disconnected orientation in which two of the torsion springs 112 a have been partially disengaged from the corresponding grid clips 106 , allowing the panel 102 a to be lowered relative to the grid 104 , and the other two torsion springs 112 have been completely disconnected from their corresponding grid clips (not shown), allowing the panel to be rotated away from the grid to provide access to the space above the suspended ceiling. The torsion springs 112 are typically attached to the individual panels using a series of panel clips 110 (not shown) that are attached to the metal frame 108 at appropriate points around the edge of the metal frame. [0004] FIG. 2 illustrates in more detail the construction and configuration of the various mechanical elements in a conventional frame type panel system according to FIG. 1 . As illustrated in FIG. 2 , the support grid may be formed from a plurality of T-bars 250 , each of which may include a foot flange 253 , a web 251 and a bead portion 254 . Grid clips 230 may be provided on or attached to the bead 254 using a releasable fastener, such as screw 240 . As illustrated, each grid clip 230 includes a U-shaped channel 232 and an opposed pair of projecting flanges 234 in which a slot 236 is provided. [0005] The arms 218 of the torsional springs 214 are arranged and configured to fit into the slot 236 and provide a frictional fit sufficient to hold the panel 200 in place against the foot flange 253 when the panel is in the installed position. The arms 218 of the torsional spring 214 may also be provided with retaining feet 220 or other structures that are arranged and configured to rest against an upper surface of the projecting flange 234 for suspending the panel when lowered into a disengaged position below the grid. The arms 218 of the torsional spring 214 may also be arranged and configured so that they may be manually deflected to release the engagement between the retaining feet 220 and the projecting flange 234 and allow the panel or one side of the panel to be completely detached from the grid. [0006] Each framed panel 200 includes a frame 226 formed around the outer edge of the tile 228 . The framed panel 200 may include an optional cover 210 of fabric or other suitable materials. A frame clip 212 fits onto a flange provided on the frame 226 and provides a raised hook portion that is configured fit through the wound portion 216 of the torsional spring 214 and thereby suspend the panel from the torsional spring. [0007] To fit the framed panel 200 against the T-bars 250 , the arms 218 of the torsion spring 214 are pushed up through the slot 236 resulting in the arms 218 spreading out in a v-shape. Consequently, the frame 226 (or the fabric 210 ) will bear against the foot portion 253 of the T-bar. To assist in aligning adjacent panels, an optional alignment clip 290 can be attached to the T-bar 250 . SUMMARY OF THE INVENTION [0008] Exemplary embodiments of the present invention provide an improved frame clip arranged and configured to be easily field-mounted and/or easily reconfigured on a panel frame. The ease with which the frame clip may be attached to a panel frame without contacting the panel tile allows the panels to be shipped without frame clips and/or torsion springs, thereby simplifying the packaging and reducing the likelihood of shipping damage resulting from projecting edges. [0009] The improved frame clip also provides a locking function for securing the wound portion of a torsion spring or other attachment means to a panel frame as the frame clip is secured. This locking function simplifies panel installation and removal by ensuring that the torsion springs are not dislodged as a result of panel movement and reducing the likelihood that a panel will drop unexpectedly while being handled. [0010] The improved frame clip may be attached to the panel frame using a variety of fastening means. For example, the channel wall of the panel frame may be provided with a groove or other indents centered opposite the channel opening to aid in the attachment of the frame clip using self-drilling fasteners. Similarly, the receiving portion of the panel frame can be provided with holes for self-tapping fasteners or may contain a nut or other element for receiving the forward portion of a fastener. The panel frame may also be provided with notches, detents or other positioning indicia to improve the ability of an installer to position the frame clip accurately and repeatedly. BRIEF DESCRIPTION OF THE DRAWINGS [0011] The accompanying drawings are intended to depict exemplary embodiments of the invention to aid those of ordinary skill in the art in understanding the present invention and should not be interpreted in such as manner as to limit the scope of the present invention to the illustrated embodiments. Similarly, the accompanying drawings are not, unless explicitly noted, drawn to scale and should not be interpreted in a manner that limits the size, spacing or relative dimensions of the illustrated mechanical elements. [0012] FIG. 1 is a three-quarter perspective drawing of a conventional suspended ceiling system utilizing torsion spring attachments; [0013] FIG. 2 is a more detailed view of a conventional torsion spring attachment system suitable for use in the suspended ceiling system illustrated in FIG. 1 ; [0014] FIGS. 3 A-C are plan, side and front views of a frame clip according to an exemplary embodiment of the present invention; [0015] FIG. 4 provides a three-quarter view of a panel frame according to an exemplary embodiment of the invention; [0016] FIGS. 5 A-D are a sequence of views illustrating the insertion and mounting of a frame clip as illustrated in FIGS. 3 A-C into a corresponding panel frame according generally to FIG. 4 ; [0017] FIGS. 6 A-C are views illustrating exemplary embodiments of frame clips utilizing various exemplary hook configurations; [0018] FIGS. 7 A-C are views illustrating exemplary combinations of frame clip inserts and corresponding panel frame channel configurations; [0019] FIG. 8 illustrates the mechanical relationship of certain structural elements of a frame clip according generally to FIG. 3A when installed in a panel frame generally according to FIG. 4 to form an exemplary embodiment of the present invention; [0020] FIG. 9 illustrates a range of motion for a captive torsion spring attached to a panel frame using a frame clip according to an exemplary embodiment of the invention; [0021] FIGS. 10A and 10B provide a plan view of the action of a parallelogram nut suitable for use in combination with a frame clip and frame according to exemplary embodiments of the present invention; and [0022] FIGS. 11A and 11B provide a side view of a parallelogram nut according to FIGS. 10A and 10B being used in combination with an exemplary frame clip, frame and fastener in accord with the present invention. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS [0023] As illustrated in FIGS. 3 A-C, an exemplary frame clip 10 according to the present invention includes a main body 12 that includes a top surface 14 , a bottom surface 16 , a first length 18 and a first width 20 and is generally planar. The frame clip 10 also includes an insert 22 that has an upper surface 24 , a lower surface 26 , a second length 28 and a second width 30 and, like the main body, is generally planar but is offset from the main body 12 by an offset depth 32 and an offset length 34 . The frame clip 10 also includes a neck 36 that connects the main body 12 and the insert 22 and maintains their relative parallel and spaced apart orientation. The frame clip 10 also defines a longitudinal axis and may be generally symmetrical about the axis. [0024] The frame clip 10 also includes a hook 38 extending above the main body 12 that includes a free forward portion 40 and is attached to the main body of the frame clip at a rear portion 42 . The hook 38 is typically oriented in a plane generally perpendicular to both the plane defined by the main body 12 and the longitudinal axis of the frame clip 10 , but depending on the particular application, other orientations may be utilized. The forward portion 40 of the hook may extend downwardly to a point generally adjacent a plane defined by the bottom surface 16 of the main body 12 or by an upper surface of a frame to which the frame clip is attached. [0025] The forward portion 40 of the hook 38 is also set apart from the main body by a distance sufficient to allow the wound portion 44 of a torsion spring 46 to be placed on the hook without interference from the main body 12 . Depending on the location of the forward portion 40 of the hook 38 , a notch or recess 48 may be provided at a corresponding edge in the main body 12 of the frame clip 10 to ensure sufficient spacing is available. The frame clip 10 may also include one or more openings 65 arranged on one or both sides of the hook 38 through which a fastener may be inserted to secure the frame clip to a panel frame. [0026] As illustrated in FIG. 4 , the frame clip 10 is arranged and configured to be used with a corresponding frame 52 . The frame 52 may be constructed of a metal, such as aluminum or an alloy, or a polymeric material that may include reinforcing materials. The frame may be formed by extrusion, pultrusion, machining or casting depending on the material(s) used and the intended application, but a conventional aluminum extrusion will generally be satisfactory. The frame 52 includes a channel 54 into which the insert 22 will fit, the channel having an inner periphery, inner shoulder surfaces 56 , outer shoulder surfaces 58 , a rear wall 60 , a longitudinal opening 62 and a longitudinal channel axis. The frame 52 may also include a groove, notch or other structures on the rear wall 60 of the channel 52 to improve the ease with which self-tapping or self-drilling fasteners may be inserted into the rear wall. The frame 52 will also typically be provided with another channel, slot or projections 68 arranged and configured to receive and support a ceiling tile or similar object within a completed panel frame. [0027] FIGS. 5 A-D illustrate a method of attaching a frame clip 10 to a corresponding frame 52 . As illustrated in FIG. 5A , the thickness of the frame clip 10 is smaller than the opening 62 into the channel 54 provided in the frame 52 , thereby allowing the frame clip to be appropriately oriented with the insert 22 positioned in the channel. As illustrated in FIG. 5B , the frame clip 10 can then be rotated generally about a longitudinal axis so that the insert 22 , which is preferably configured to have an outer periphery generally corresponding to, but slightly smaller than, at least portions of the inner periphery of the channel 54 will be held in the channel. Similarly, the neck 36 of the frame clip 10 is typically configured to have a maximum width slightly smaller than the width of opening 62 so that the frame clip can be rotated without binding on the sides of the opening. As illustrated in FIG. 5B , the insert 22 is configured to be wider than the opening 62 into the channel so that when the plane of the frame clip 10 is substantially perpendicular to the longitudinal channel axis, attempting to remove the frame clip from the channel causes the insert to contact the inner shoulder surfaces 56 of the frame 52 and thereby tend to retain the insert within the channel. [0028] As illustrated in FIG. 5C , a torsion spring 46 can then be slipped over the free forward portion 40 of the hook 38 provided on the frame clip 10 . As illustrated in FIG. 5D , the frame clip 10 can then be rotated about a transverse axis positioned near or extending through the neck 36 portion. The repositioning of the frame clip 10 typically establishes contact between the bottom surface 16 of the main body 12 and the outer shoulder surfaces 58 of the frame 52 as well as between the upper surface of the insert 24 and the inner shoulder surfaces. The forward portion 40 of the hook 38 will also be moved adjacent a portion of the frame 52 to secure the torsion spring on the hook 38 as the frame clip is rotated to its installed position. Once the frame clip 10 is appropriately positioned, a fastener such as a screw 64 can be attached to the frame through a portion of the frame clip. One or more holes 65 or thinned portions may be provided in the main body 12 of the frame clip to assist in the insertion of an appropriate fastener. [0029] As illustrated in the FIGS. 6 A-C, the hook 38 may be positioned in a number of orientations relative to the main body 12 of the frame clip 10 . A preferred embodiment is illustrated in FIG. 6A in which the hook 38 is provided generally within the periphery of the main body 12 with a notch or recess being provided in the main body to ensure sufficient clearance to allow a torsion spring or other structure to be placed on the hook. As illustrated in FIGS. 6B and 6C , however, the forward portion 40 of the hook 38 can be extended well away from the main body 12 , provided there is other structure, such as a portion of the frame 52 that can interact with the forward portion of the hook to close the opening or at least decrease the width of the opening sufficiently to prevent a structure on the hook from being removed from the hook while the frame clip 10 is in its fully installed position. [0030] As illustrated in FIGS. 7 A-C, both the channel 54 provided in the frame 52 and the insert 22 of the frame clip 10 can assume a wide range of configurations. Further, although, as illustrated, the outer periphery of insert 22 and the inner periphery of the channel 54 are similar, those of ordinary skill in the art will appreciate that a wide range of shapes may be used successfully. Each of the range of configurations will, however, include an insert that is wider than the opening 62 and will contact the inner shoulder surfaces 56 of the channel if an attempt is made to remove the frame clip 10 without first rotating the frame clip to a position in which the upper surface of the insert is generally aligned with the longitudinal channel axis. [0031] As illustrated in FIG. 8 , when installed the frame clip 10 will be positioned securely on the frame 52 to hold a torsion spring 46 or other connecting apparatus that will allow the panel, including a supported tile 70 , to be attached to a suspended grid. Typically a series of frame clips 10 will be located on the frame 52 with four or more sections of frame used to encompass and/or support the edges of a tile 70 , panel or other structural element. The use of frame clips 10 according to the present invention located along the sides of the frame sections allows the corners of the frames to be reinforced more strongly and may reduce or eliminate the need for gussets or other external reinforcing structures. This allows the basic panel frames to be assembled and shipped in a manner that reduces the likelihood of damage resulting from protruding structures and allows the installers to quickly install and position the necessary frame clips and supporting structures in the field. [0032] As illustrated in FIGS. 10 A-B, a preferred means of attaching an exemplary frame clip to the frame utilizes a nut 72 arranged and configured to allow insertion of the nut into the channel 54 through the opening 62 in one orientation and, by rotating the nut within the channel, to hold the nut within the channel and stop its rotation so that a fastener, such as a screw, can be tightened against the nut. As illustrated in FIGS. 11 A-B, the use of such a nut 72 , allows the combination of a frame clip 10 , fastener 64 and nut 72 sub-assembly 74 . With the nut 72 oriented appropriately, the sub-assembly 74 can then be inserted into the channel 54 as generally illustrated in FIGS. 5 A-D. Once the sub-assembly 74 is in place on the frame 52 , rotating the fastener 64 will cause the nut 72 to rotate and lock into the channel 54 and additional rotation of the fastener will cause the nut and the frame clip 10 to be securely attached to the shoulder portions of the channel. Although the illustrated nut 72 has a generally parallelogram shape, other configurations that allow the insertion of the nut through the channel opening and will contact the periphery of the channel when rotated to provide a “locking” function may be used in this manner. A self tapping screw may be used to secure the clip 10 to frame 52 without the use of nut 72 . [0033] The dimensions of the frame clip 10 may also be adjusted to provide an offset depth 32 that is slightly smaller than the thickness of the shoulder portions of the channel 54 . When the offset depth 32 is adjusted in this manner, some deformation of the main body 12 , insert 22 and/or of the neck 36 will occur as the frame clip 10 is being fastened to the frame 52 and provide a “locking” effect that will assist in maintaining the position of the frame clip as the fastener is rotated into a fully seated position. Similarly, the upper surface 24 of the insert 22 and/or the lower surface 16 of the main body 12 may be provided with projections or tabs that are configured to mate with corresponding detents or recesses in the frame 52 to help maintain the position of the frame clip 10 relative to the frame while the fastener 64 is being inserted and seated. [0034] Those of ordinary skill in the art will appreciate that the present invention may be embodied in forms other than those specifically illustrated and described herein departing from the spirit and essential characteristics of the invention. The exemplary embodiments of the invention described in detail above and illustrated in the accompanying figures are intended to aid in the understanding of the invention but should not be interpreted as unduly limiting the scope of the invention as defined in the appended claims. All changes which come within the meaning and equivalency of the claims are to be embraced.	The present invention provides an improved frame clip arranged and constructed to be easily field-mounted and/or reconfigured on a panel frame such as those used to form suspended ceilings. By allowing the installation of the frame clips to be deferred until the panels are being installed, the frame clip permits the panels to be shipped without frame clips and/or attachment hardware, such as torsion springs, installed, thereby reducing the likelihood of shipping damage.
You are an expert at summarizing long articles. Proceed to summarize the following text: OTHER APPLICATIONS This application is a continuation-in-part of my earlier filed copending application Ser. No. 455,475 filed Jan. 4, 1983. FIELD OF INVENTION This invention relates to shades for solar greenhouses and the like and more particularly to improved structural members suitable for providing guidance for shading and like types of members. Commercial systems are available for providing selective shading for solar greenhouses and the like. In one known arrangement, a shade is transferred from one motor driven roller towards a second motor driven roller by straps which are fastened to the leading edge of the shade, these straps being attached to one of the rollers and being wound upon the same to draw the shade from the other roller upon which the shade is coiled and normally stored. In addition, the leading edge of the shade is provided in the form of a rigid member, the edges of which are guided in a channel provided in a guiding member which has no structural function and is intended solely for the purpose of being a shade guide. An inspection of the available system reveals that the leading rigid element of the aforegoing system extends laterally beyond the lateral edges of the shade so that the lateral edges of the shade are spaced from the guide and thus provide means for an inadvertent passage of solar radiation or the like between the guides and the shade edges. It is also to be noted that the guides have no structural function to be formed as has been noted hereinabove, and that the guides are generally mounted inwardly of the solar greenhouse structure in such a manner as to be readily receptive of inadvertent damaging forces or the like. Moreover, it will be noted that the shade is inconveniently positioned with its lateral edges subject to damage and deterioration. Also commercially available are shades having lateral edges into which are incorporated wires or cables or the like which give to these lateral edges a conformation which is bulbous in nature. These bulbous lateral edges are accommodated in guiding tracks which heretofore have been exclusively rectilinear and solely vertically disposed. These shades have not been incorporated into solar greenhouses or other such complex structures for purposes of providing selective shielding or shading. Also commercially available are rollers within which are provided internal motors of generally cylindrical conformation. These motors are utilized for selectively driving the rollers for taking up straps attached to shades or for rewinding shades and the like. Insofar as I am aware, these motor driven rollers have not been utilized in conjunction with the structural members of solar greenhouses or the like in the manner which will be described in greater detail hereinbelow. SUMMARY OF INVENTION It is a general object of the invention to provide improved systems and structural members to enable the selective shading and shielding of solar greenhouses and the like. It is a further object of the invention to provide improved structural elements suitable for use in solar greenhouses and the like in order to provide for ready installation and operation of shading systems and so forth. Yet another object of the invention is to provide for improved insulating and shading systems for solarium type greenhouses and the like utilizing integral built-in tracks to carry shading fabric so that the fabric may be readily held taut between two such tracks without sag and incorporating guide members which are easily installed and which provide an anti-sag feature. Yet another object of the invention is to provide an insulating and shading system wherein integral built-in track channels are made accessible at the top and bottom of the tracking system by improved designing of the structural members into which the integral tracks are incorporated. To achieve the above and other objects of the invention, there is provided an apparatus comprising spaced parallel bars defining parallel channel tracks with facing mouths. A shade extends laterally through the mouths and includes bulbous peripheries accommodated and retained in these tracks. The bars include ends at which the shade selectively enters and exits the tracks. A roller arrangement is operatively associated with the ends to take up and play out the shade. For structural purposes, the roller arrangement is displaced from the bars and, in accordance with the invention, there is provided a guide arrangement to guide a change in direction of the shade as the shade enters or exits the tracks in order to adapt the shade to the relative positions of the roller arrangement and the ends of the bars. In accordance with a further aspect of the invention, the guide arrangement is provided with open guide tracks for receiving the bulbous peripheries and these guide tracks are of arcuate configuration whereby to change direction of the bulbous peripheries and thereby the direction of the shade. In addition to the aforesaid, the guide tracks on the different bars have proximal lateral guide walls which slope apart in the direction of the ends of the bars whereby to effect a stretching of the shade. The aforesaid guide tracks may be provided with distal lateral guide walls which slope together in the direction of the ends of the bars and such that the guide tracks are of generally funnel shape. In accordance with a feature of the invention, the guide tracks are of arcuate cross-section and this cross-section will preferably have a radius which increases in a direction away from the ends of the bars. In accordance with another feature of the invention, the guide arrangement will include tubular extensions in continuation of the guide tracks, the tubular extensions being accommodated in the channel tracks at the ends of the bars and coupling the guide arrangement to the bars. In accordance with other aspects of the invention, the bars each include a wall extending between the channel tracks with the guide arrangement including further extensions which with the corresponding tubular extensions straddle the aforementioned wall. The wall may be provided with a threaded opening and the further extensions mentioned hereinabove will be provided with an opening aligned with the threaded opening, the apparatus further including a locking member extending through the openings and engaging in the threaded opening. Still further, the ends of the bars will preferably be sloped relative to the channel tracks and the guide arrangement will include flanges sloped relative to the tubular extensions and in correspondence with the sloped ends. The aforementioned guide arrangements may be included in single monolithic guide structures. One such guide structure may include a body defining two funnel shaped and generally arcuate guide tracks having generally parallel axes and there may furthermore be provided two parallel tubular extensions on the aforesaid body defining bores aligned in continuation of the guide tracks. These bores will preferably by generally tangentially related to the guide tracks. In the aforesaid construction, each of the tubular extensions will preferably be provided with a lateral slot extending longitudinally therealong and through which the shade may extend with its periphery being accommodated at least partly in the corresponding tubular extension. Another feature relates to the provision of a flat extension on the aforesaid body spaced from but parallel with the tubular extensions. Still further, there may be provided a flange on the aforesaid body in sloped relationship to the tubular extensions. Other feature include that the guide tracks are at least about one-quarter of a circle in extent with the guide tracks being of varying arcuate cross-section which increases in a direction away from the corresponding tubular extensions. Still another feature of the invention relates to the guide tracks having outer walls which slope at about 10°-45° relative to the associated axes. The above and other objects, features and advantages of the invention will be found in the detailed description which follows hereinafter, as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF DRAWING In the drawing: FIG. 1 is an interior perspective view of a portion of a lean-to type solar greenhouse provided with a shading arrangement to accordance with a preferred embodiment of the invention; FIG. 2 is a partly diagrammatic and perspective view of a broken-away protion of the bottom sill construction embodied in the structure of FIG. 1 in correspondence with line A--A in FIG. 1; FIG. 3 is a view of the ridge structure of FIG. 1 in correspondence with line B--B therein, the view being on enlarged scale and being partially diagrammatic in nature; FIG. 4 is a partially diagrammatic view corresponding to section line B--B of FIG. 1; FIG. 5 is a sectional view corresponding to line C--C in FIG. 1 but further illustrating a glazing and muntin connected thereto; FIG. 6 is a top view of a guide constituting an element of the invention utilized in connection with the aforegoing structure; FIG. 7 is a side view of the guide of FIG. 6 illustrating its cooperation with a glazing bar shown partially broken-away and in sections; FIG. 8 is a bottom view of the guide of FIG. 8 illustrating its cooperation with a glazing bar as in FIG. 7; and FIG. 9 is a diagrammatic view illustrating the operation of the guide means in cooperation with the other structures of the invention. DETAILED DESCRIPTION In FIG. 1 is illustrated a portion of a lean-to type solar greenhouse of the kind generally shown in the 1982 Theme Catalog entitled Four Seasons Passive Solar Greenhouse and Sun Space published and distributed by Four Seasons Solar Corp. of Farmingdale, N.Y. The illustrated portion of the Solar Greenhouse in FIG. 1 includes a gable end 10 and a front portion 12 having a curved-eave portion 14 and an upper sloped portion 16. Further illustrated are base sills 18 and 20 which may, for example, be mounted on a base wall or flat slab or deck (not shown) with appropriate fasteners. The method of mounting the base sill on the supporting ground is not a feature of the present invention and requires no further description in this text. The gable end 10 includes a plurality of parallel vertical glazing bars such as indicated at 22, 24, and 26. The bar 26 is in abutting relationship against the side of a dwelling or some other such similar construction. The front portion 12 includes a plurality of vertical glazing bars 28, 30, 32, 34 and 36. The glazing bar 36 furthermore provides a connection with gable end 10. To conform with the shape of the glazing, which it is the purpose of the glazing bars to support, the glazing bar 28 has a curved section 38 and a sloped section 40. It terminates in an end portion 42. Glazing bars 28, 30, 32, 34 and 36 have similar curved and sloped portions. Glazing panes as comprised by the gable end 10 are indicated in various forms at 44, 46, 48, 50, 52, 54 and 56. Portions of the glazing are concealed by shade fabric as indicated at 58, 60 and 62. The dwellings or other structure against which the solar greenhouse is mounted is not shown as its construction is not essential to an understanding of the present invention. The glazing included in the front portion 12 includes glazing panes 70, 72, 74 and 76. The remaining glazing in FIG. 1 is concealed by shade fabric or shades 80, 82, 84 and 86. The number of shades and panels in FIG. 1 is illustrative only as a greater or lesser number of panels and glazing panes may be employed in accordance with the invention which is not limited thereby. At the upper end of the solar greenhouse construction, is located a ridge structure 90. It engages the end portion of the glazing bars at the upper extremities thereof such as indicated at 42 to support and accommodate the same. The ridge structure 90 abuts at the back wall 92 against the dwelling other similar structure associated therewith as does the vertical glazing bar 26 of the gable end 10. Also appearing in FIG. 1 is a representative sequence of rollers 94, 96, 98 and 100. These rollers in the illustrated embodiment are source rollers of shade fabric which store and supply the rolled up shade fabric upon demand. Further illustrated in FIG. 1 is a guide roll arrangement 102 which guides the shades or shade fabric in a change of direction so that the edges of these shades or fabrics may be engaged in track channels provided in the vertical glazing bars as will be described in greater detail hereinbelow. It is to be noted in the diagrammatic illustration of source rollers 94, 96, 98 and 100 that interior motors 110, 112, 114 and 116 are shown. These motors are contained and concealed within the rollers and operate to drive the same. Rollers with internal motors to drive the same are commercially available. They may be obtained from Somfy Systems, Inc. of Edison, N.J. The motors are of a asynchronous capacitor start and run, single phase type rated at 120 V. and 60 Hz. They are thermally protected totally enclosed brushless type motors equipped with permanently lubricated bearings requiring no maintenance and being relatively easy to wire. They include solenoid activated disc brakes which automatically stop and hold a load in any position without slippage whenever current to the motor is interrupted. The locking action assures safety and reliability of operation of the motorized system. The system can be provided with a limit switch to set the exact length of travel in both up and down directions automatically. A planetary type gear system is employed to lower motor speed and improve torque. Other details of the motor system can be found in U.S. Pat. No. 3,718,215. The upper motorized rollers cooperate with corresponding motorized rollers concealed in the base sill 18. In the illustration, one motorized system is exposed by the cutaway such as, for example, seen at 120. The arrangement is such that, when the rollers in the sill 18 are operated to draw shade fabric downwardly, the motorized roller systems indicated at 94, 96, 98 and 100 permit the withdrawing of shades therefrom. The electrical system and operation is reversed when the shades 80, 82, 84 and 86 are to be drawn upwardly. In this case, the motorized systems indicated at 94, 96, 98 and 100 are actuated and the concealed systems in the base sill 18 release the material for being rolled back upon the upper rollers to expose greater, and greater amounts of the glazing as the operation continues. Also illustrated in FIG. 1, in diagrammatic form, is a photoelectric sensor 126. This photoelectric sensor is coupled in an electric circuit (not shown) connected with the aforementioned motors in order to drive the same in one or the other rotary directions as may be required. The photoelectric sensor 126 is representative only of any device capable of sensing an ambient condition such as solar radiation, temperature, wind and the like for purposes of automating the operation of the rollers. It will be noted, however, that, while the motorized roller systems are employed in accordance with the preferred embodiment of the invention, it is also possible that the shades be operated manually and also in connection with spring-loaded rollers as is the case in connection with domestic shades as are commonly and commercially available. In fact, a manually operated shade arrangement is indicated in association with end 10. Thus, there are no upper rollers associated with shades 58, 60 and 62, these being drawn from concealed rollers in base sill 20 by a manual operation of grasping rigid leading edge members indicated by way of example at 130, 132 and 134. Also exposed in the illustration of FIG. 1 in diagrammatic form is a blower 140. The purpose of this blower (as will be illustrated and described in greater detail hereinbelow) is to evacuate air from between the shade and the associated glazing and to expel this air into the ambient atmosphere via an appropriate vent in order to reduce the temperature which prevails between the shades and the glazing thereby to reduce the possibility of damage to the glazing. FIG. 2 illustrates on an enlarged scale a broken-away portion of the structure illustrated in FIG. 1 with conditions somewhat altered to show a more lowered condition of the shades. For purposes of orientation, it will be seen in FIG. 2 that there are illustrated base sill 18, vertical glazing bar 30 and shades 80 and 82. The base sill 18 includes an inner wall 150 and a first outer wall 152. The outer wall 152 supports a sloped upper wall 154 from which extends a vertical wall 156. The walls 154 and 156 cooperate to define a moisture drain 158. A bottom wall 160 extends between and connects the inner wall 150 with the outer wall 152. Drainage channels 162 and 164 are provided in horizontal disposition within the internal chamber 166 which is cooperatively defined by walls 150, 152, 154 and 160. Within the chamber 166 is accommodated the motorized roller system including the internal motor 170 and the encircling roller 172. Each of the shades illustrated includes a bulbous lateral edge portion for purposes of being accommodated in and guided by track channels to be referred to hereinbelow. Illustrative bulbous lateral edge portions or peripheries are indicated at 176 and 178 in FIG. 2. These constructions are commercially available and are generally of the type including wires extending through the bulbous peripheries and axially extending out of the same. Two such wires or cables are indicated at 180 and 182 in FIG. 2. They extend through and are guided by track channels 184 and 186 as will be described in greater detail hereinbelow. It is to be noted that, by reason of break-away portion 188, it is possible to see that these cables are attached to and wound onto roller 172 such as indicated 190 and 192. A winding up of these cables on the roller 172 causes the shades 80 and 82 to be drawn down towards the base sill 18 thereby to effect a greater degree of shading. This means that solar radiation passing through the glazing which is permeable thereto may be intercepted by the shades thereby to effect a greater or lesser degree of shielding as desired and as may be manually or automatically controlled. It will also be noted in FIG. 2 that the shades 80 and 82 are provided with rigid lead members 196 and 198. These members, at their extreme downward movement, come into abutting or substantially abutting relationship with cap elements 200 and 202 which are intended to cover drains such as indicated at 158 and to conceal the internal construction of the base sill 18 from viewing or from the damaging impact of dropped articles or the like. The caps 200 and 202 also constitute safety features inasmuch as they resist the penetration of probing fingers and the like which might otherwise be damaged by engagement with moving parts within the base sill 18 under inadvertent circumstances. The cap members 200 and 202 extend generally from the vertical wall 156 to the upper lip 204 of the front wall 150. This is satisfactory in the case where the cables, such as indicated 180 and 182, extend through the glazing bar to the internal roller 172 which in this case acts take-up roller. In these circumstances, there is no need for the lead members 196 and 198 to move into the internal chamber 166 nor is there any need for the shade 80 or 82 to do likewise. In the event that it is desired to alter the construction so that the shade 80 and 82 can be directly taken-up on the roller 172 in addition to the cables 180 and 182 which they trail, the construction can be readily modified to provide a slot through which the shade 80 and 82 may pass. Thus, for example, the cap member 200 is provided with a notch 210 providing a break-away section 212 to expose a slot or passage 214 illustrative of a passageway through which the shades may enter the internal chamber 166 for engagement and being taken-up upon an associated roller. Thus, the invention includes the options whereby it is exclusively the cables which are taken-up on the lowermost roller or rollers or whereby the shades themselves are taken-up upon such roller or rollers. FIG. 2 furthermore illustrates a second outer wall 220. This outer wall includes a protrusion 222 in facing relationship with a protrusion 224 on the outer wall 152. These two protrusions are provided with facing grooves 226 and 228 which have reentrant angles therein so that a thermal break member 230 having the form of a Maltese cross may be entrapped therein to prevent the flow of heat from the wall 152 to the wall 220. The glazing is illustratively shown in the form of a double paned glass or plastic structure, the spaced panes being indicated at 240 and 242 with a spacing 244 therebetween To maintain this spacing, there is provided a spacer 246. The pane 242 restsagainst the vertical wall 156 and the glazing as a whole is entrapped between the walls 156 and 220 by means of a gasket 250 of a theremally insulative type. The upper walls of protrusions 222 and 224 define a platform at 252 and 254 upon which rests a pad 256 upon which rest the glazing and the spacer 246. Further reference to the construction of the vertical glazing bar 30 will be made hereinbelow since the construction of this bar and other like bars in the structure constitute a significant feature of the invention, especially as regards the provision of the track channels 184 and 186. Before this discussion is undertaken, however, reference will next be made to FIGS. 3 and 4 which illustrate, in greater detail and/or diagrammatically, some of the features of the ridge structure 90 appearing in FIG. 1. For purposes of orientation, attention is drawn in FIGS. 3 and 4 to vertical glazing bar 30, shades 80 and 82, motorized roller system 94, guide roll 102 and blower system 140 which have been mentioned hereinabove. A guide 121 is shown in a diagrammatic form in FIG. 3 and its details will be later explained. From what has been stated above, it will not be obvious that the glazing bars constitute supporting members or structures for the glazing. These supporting members are accommodated in and rest against the ridge structure 90. They provide track channels for receiving and guiding the respective shades. The ridge member 90 is structurally and functionally related therewith in a manner next to be described below. Ridge structure 90 includes a rear wall 300 consisting of upper and lower parts 302 and 304. The upper and lower parts are connected through the intermediary of a thermal break member 306 which is made of insulative material accommodated in appropriate receptacles 308 and 310 respectively provided on the upper and lower parts 302 and 304. The ridge structure 90 also include upper wall 312 and lower wall 314. Moreover, it includes a front wall indicated at 316. Cooperatively, these walls define an internal chamber 318 within which is accommodated the blower 140. The front wall 316 is provided with a vent indicated generally at 320. Associated with this vent is a removable shutter 322 which may be employed, for example, during cold weather seasons to shut off the escape of air from within the solar greenhouse. The front wall 316 has an auxiliary portion 324 connected thereto through the intermediary of a thermal break member 326. This auxiliary member 324 supports a receptacle 328 which is a glazing receptacle to accommodate and support appropriate glazing panels at the upper extremity of the front portion of the glazing of the solar greenhouse. An exemplary panel is diagrammatically illustrated at 330. It may consist of spaced panes 332 and 334 separated, for example, by a spacer 336. The panel 330 is held in place by a gasket shown at 338. A screen for preventing the influx of insects and the like is indicated at 340. It is associated with the vent 320. A second vent is indicated at 342. Cooperating therewith is a gravity operated flap 344 which likewise prevents the influx of foreign matter. The strength of the flow of air passing outwardly through the vent 342 is sufficient to open the flap 344 to the extent required. FIG. 4 specifically illustrates the flow of air. Flow through the vent 320 is indicated by arrows 350 and 352. Flow of air through vent 342 is indicated by arrow 354. The circuitous route is indicated by dotted line path 356. It will now be noted that the utilization of the glazing bar with its track channels 184 and 186 and the function of supporting the associated glazing defines a space between the shades and glazing. This space is indicated in FIG. 4 at S. This spacing S is a minimum of about 11/2 inches. It is intended to assist in limiting the temperature which air entrapped between the glazing and shade may reach. This function is further accomplished by the utilization of the blower 140 which displaces or withdraws air from between the glazing and the shades and propels this air along the route 356 through the vent 320 and expels this air into ambient atmosphere through the vent 342. The the ridge structure and its blower cooperate with the glazing bar and the shades in both a structurally supportative and temperature controlling manner. It will now be noted that the end portion 360 at the upper extremity of the glazing bar 30 has an extremity indicated at 362 which is angularly related both to the longitudinal axis of bar 30 and to the rear wall 304 of the ridge structure 90. This is intended to provide a space 364 within which to accommodate at least a partial intrusion of the guide roll 102. Thus the guide roll 102 may be conveniently positioned to guide the shade 80 from the roller system 94 into the associated track channels. Similarly, the bottom extremity of the glazing bar 30 as indicated at 366 in FIG. 2 is angularly related to the walls between which it extends. The purpose of this angular construction is different from that at the upper extremity. It is intended to provide an appropriate relationship with the drain 158 thereby to permit a proper resting of the bottom extremity of bar 130 on the upper wall 154 and to permit an ease in installing the glazing bar 30 when the structure is being assembled. An examination of FIG. 5, which is in part, a section of glazing bar 30, will next be undertaken in conjunction with an understanding of FIGS. 2, 3, and 4. In FIG. 5 appears the track channels 184 and 186. By reference to the other figures, it will be understood that these channels extend longitudinally through the glazing bar which is itself an extended member. Associated with the channel 184 is a mouth 400. Associated with the track channel 180 is a mouth 402. These mouths are of relatively restricted dimensions. They form and constitute slots extending longitudinally along the glazing bar 30. The track channels 184 and 186 are in a preferred embodiment of the invention preferably of circular conformation. An example diameter of these track channels is indicated at D. The width of the associated mouths 400 and 402 is indicated by way of example at W. The arrangement is such, that the width W is preferably no more than 50% of the dimension D. This, in effect, forms a reentrant angle indicated, by way of example, at A. The purpose of this is to form a track channel in which the bulbous periphery of the associated lateral edges of the corresponding shades are entrapped. This entrapment coupled with appropriate spacing of pairs of associated glazing bars enables the shades to be held in taut condition thereby avoiding sagging and the like. It also enables the bulbous portions to be vigorously guided along appropriate paths even as these paths turn through an angle associated with the curve eave portions of the overall construction. Thus the use of associated guide rolls or the like in the vicinity of the curved eave portions is avoided. It will be noted that the glazing bar includes two side walls 404 and 406. These side walls extend between and connect inner wall 408 and outer wall 410. The arrangement of the wall is such that the glazing bar is in its preferred form quadrilateral in cross-section thereby defining four corners indicated in the drawing at 412, 414, 416 and 418. The track channels 184 and 186 are generally located at the corners 416 and 418. They are furthermore formed by interior walls indicated at 420, 422, 424 and 426. The walls 420 and 424, which partly define channels 184 and 186, have surface 428 and 430 which are flat. They also have surfaces 432 and 434 which conform to the shape of the channels. On the other hand, wall 422 has surfaces 436 and 438 both of which conform to the shape of the associated channel. Wall 428 likewise has surfaces 440 and 442 which conform to the shape of the associated channel 186. In the wall 408 is provided a screw threaded groove 450. By means of this groove, attachments of various types may be provided by fastening members threadably engaged therein to provide for the connection or hanging of various types of auxiliary members or elements on the interior of the solar greenhouse. A corresponding grooved slot 452 is provided in wall 410. This provides for the utilization of fastening member 454 to sandwich glazing panes, for example, 456 and 458 against the supporting structure by means of a muntin 460 or clamping member which is entrapped by the head 462 to sandwich the glazing against the sealing members 464 and 466 accommodated in sealing receptacles 468 and 470 mounted on the outer wall 410 and constituting an integral part thereof. It will be furthermore noted that the wall 410 is provided with drainage grooves 472 and 474. The provision of these sealing receptacles and drainage has been heretofore available, but never in association with track channels and never for the partial purpose for extablishing a rigid spacing therebetween so as to provide a well defined spacing between a glazing and a associated shade arrangement as in accordance with the present invention. Reference to FIG. 2 will show the orientation of screw threaded grooves 450 and 452 as well as seals 464 and 466 accommodated in their respective receptacles. The illustration will also show the orientation of drainage grooves 472 and 474. Not heretofore mentioned with respect to FIG. 2 is the chamber 480 defined between outer walls 152 and 220. This provides an accommodation for the upper extremity of flashing 482 the purpose of which is to provide a weather seal as between the bottom of the base sill 18 and the exterior supporting ground or other such construction. Reference of FIG. 3 will likewise show the orientation of screw threaded grooves 450 and 452 as well as of sealing members 464 and 466 as well as drainage grooves 472 and 474. From what has been stated above, it will be readily understood that the support arrangement of the invention, when utilized in connection with glazing or the like includes a plurality of spaced parallel glazing bars, each provided with two of the afore-described track channels. These track channels are arranged in cooperating pairs and in parallel and are such that respective shades extend between these channels with the bulbous peripheries of the shades being entrapped in slidable engagement therein. The guide arrangement provided in accordance with the invention will provide a plurality of guides intended to cooperate with the aforementioned glazing bars and track channels in a manner which will become hereinafter apparent. One guide is provided as a cap for each of the aforesaid glazing bars. Each cap is intended to cooperate with the bulbous peripheries of two adjacent shades. Furthermore, each guide is intended to engage in and mate with the cooperating glazing bar and to provide for appropriate orientation therewith, as well as for a change of direction of the bulbous peripheries of the respective shades as they exit from or enter into the track channel provided in the glazing bars. The details of such guide 121 is illustrated in detail in FIGS. 6-8 wherein it is seen that the guide is formed of a body 500 having lateral edges 502 and 504 in which is provided a square opening 506. Mounted on the body 500 are a pair of tubular extensions 508 and 510. These tubular extensions are provided with lateral longitudinally extending slits or slots 512 and 514. They are arranged to be in a substantially common plane and to correspond with the mouths in the corresponding track channels of glazing bar 30. Thus, the bulbous peripheries of the two corresponding shades may be accommodated in the internal circular bores 516 and 518 of tubular extensions 508 and 510 whereas the planar portion of the corresponding shades may extend through the slots 512 and 514. To augment the function of these slots, the body 500 is furthermore provided with laterally extending slots 520 and 522, the mouths 524 and 526 of which are flared to accommodate minor distortions of the shades as they pass into the tubular extensions with the bulbous peripheries thereon. The bores 516 and 518 and tubular extensions 508 and 510 are provided with parallel axes of symmetry indicated at 530 and 532. Extending orthogonally therethrough are two axes 534 and 536 which constitute axes or planes of symmetry for two funnel shaped tracks 538 and 540. These funnel shaped tracks are tracks which are extensions of the bores 516 and 518. They are at least one-quarter of a circle in extent and in the illustrated embodiment are substantially of an extent of about one half of a circle. The purpose of these guide tracks 538 and 540 is to guide the change of direction of the bulbous peripheries of the associated shades as they pass into or out of the bores 516 and 518. For this purpose, the tracks 538 and 540 are substantially tangential to the tubular extensions 508 and 510 and the bores 516 and 518 thereof. The tracks 538 and 540 have respective outer walls 542 and 544, as well as respective inner walls 546 and 548. These walls slope symmetrically at an angle 550 relative to axis 534 or 536 which is preferably comprised within the range of 10°-45°. The most functional of these walls are the walls 542 and 544 which walls are proximal to the corresponding walls on the next continguous guides (not shown) included in the guide arrangement and intended to function with respect to the same shades as are engaged in the illustrated guide 121. As will be explained in greater detail hereinbelow, the outer or proximal walls 542 and 544 are intended to guide the bulbous peripheries into the bores 516 and 518, while at the same time exerting a stretching force on the corresponding shades. This stretching force constitutes an anti-sag feature provided in accordance with the present invention. The guide tracks 538 and 540 have radii 543 and 545 which in the preferred embodiment are about 0.420 and 0.500 inches respectively. The guide tracks 538 and 540 are also of a gradually varying radius. The radius of the tubular extentions is indicated by way of example at 560. The radius adjacent the end of the guide track, which is distal with respect to the corresponding tubular extension, is indicated at 562. By way of example, the radius 560, in a preferred embodiment of the invention, is 0.1375 inches, while the radius 562 is 1.250 inches. The radius 560 is equal to one half of the diameter of the bores 516 and 518. The upper end of glazing bar 30 is indicated at 570. This end is sloped relative to the longitudinal axis of the glazing bar and is equally sloped relative to the axis 530. To nest against the end 570 the guide of the invention is provided with a sloped flange 572. The end 570 and the flange 572 slope at an angle 574 relative to the axis 530, this angle may be, for example, in the order of magnitude of 60° and is preferably within the range of 45°-75°. Nesting against the face 580 of glazing bar 30 is a flat or planar extension 582 which extends from the body 500. Extension 582 has a face 584 which is flat and in face-to-face engagement with the face 580. The face 584 is spaced from the corresponding tubular extensions by a distance indicated at 586. This distance is adequate to permit the tubular extensions and the flat extension 582 to straddle the wall 588 of the glazing bar thereby to clamp the guide in position with the flange 572 resting in nesting relationship against the end 570. Furthermore, the body is provided with a sloped section 590 which also rests against the sloped end 570. Extension 582 is provided with an opening 592. The wall 588 of glazing rod 30 is provided with a portion 596 in which is provided a threaded opening 598. The opening 592 and the opening 598 are provided in aligned relationship to accommodate a bolt or locking member 600 by means of which the guide may be locked in position atop the associated glazing bar. From the description given above, it will be seen that the guides 121, the details of which are illustrated in FIGS. 6-8, provides for a change in direction of the shade and its bulbous peripheries. Such a change in direction is illustrated in general manner in FIGS. 3 and 4. The guide is preferably a monolithic structure fabricated of a suitable plastic or of metal. The cooperation of a plurality of these guides is diagrammatically illustrated in FIG. 9 wherein, for purposes of orientation, some primed reference numerals are employed to enable considering the following explanation in view of structure which has been previously described. Thus, for example, in FIG. 9 appear shades 80' and 82' as well as guides 121', 121" and 121'". Furthermore shown are take-up rollers 121' and uppermost take-up roller 94'. It will be noted, of course, that while one roller 94' is illustrated in FIG. 9, that a series of such rollers corresponding to the respective shades might be readily employed in substitution therefor. Futhermore shown in FIG. 9 are glazing bars 30' provided with track channels or channel tracks 184' and 186'. The curved guide tracks are generally radially offset relative to the associated roller 94'. Proximal walls of the tracks are indicated at 542' and 542". Distal walls are indicated by way of example at 546' and 546". Thus, it will be seen that the proximal walls are cooperating walls of two adjacent guides whereas the distal walls 546' and 546" are arranged in this pair of guides. From the illustration in FIG. 9 it will furthermore be noted that the bulbous peripheries BP' and BP" are engaged in the channel tracks 184' and 186" relative to shade 82' whereas the bulbous peripheries of shade 80', which are indicated at BP'" and BP"", are respectively accommodated in channel tracks 186' and 184". When, for example, the shade 82' is engaged on roller 94', its width may be, for example, as shown at W'. Thereafter, its bulbous peripheries BP' and BP" pass along proximal walls 542' and 542" whereby the bulbous peripheries are fanned out for subsequent accommodation in the tubular extensions 508 or 510 and thereafter in track channels 184' and 186". This will cause an increase in width of the shade from that indicated at W' to the width indicated at W". This constitutes the leading feature of the anti-sag characteristic of the novel structure of the guide arrangement of the invention, which also simultaneously performs the function of providing a change in direction, as has been referred to hereinabove as being shown in FIGS. 3 and 4. The cap or guard provided in accordance with the invention, is also well oriented with respect to the associated glazing bar. The tubular extensions operating in conjunction with the flat extension 582 provide a bracketing device which traverses one of the walls of the associated glazing bar to hold the guide firmly in position. This characteristic feature is further enhanced by the provision of the flange 572 and the sloped wall 590. The smooth continuation or transition of the bulbous peripheries from within the glazing bar to the take-up roller and vice versa is well provided for by the insertion of the tubular extensions 508 and 510 into the associated channel tracks of the glazing bar 30. An anchoring of the guide device is afforded by the utilization of locking device 600 which passes through opening 592 in extension 582 to be received and accommodated in threaded opening 598. The lateral extension of the shades into the guide device is well provided for by openings 524 and 526 as well as by the lateral slots 512 and 514 provided in the tubular extensions. There will now be obvious to those skilled in the art many modifications and variations of the structures set forth hereinabove. These modifications and variations will not depart from the scope of the invention, if defined by the following claims.	A structural arrangement which is particularly useful in connection with solar greenhouses is provided. Therein is provided a structural member in the form of a hollow bar of elongated form provided with longitudinally extending and parallel track channels having relatively narrow longitudinally extended slot mouths. A shade with a bulbous periphery is engaged in each of the track channels and a guide member is provided which changes the direction of movement of the shade as it exits from the ends of the corresponding track channels. The guide includes tubular extensions which extend into the track channels. The guide furthermore includes arcuate guide channels which are funnel shaped and operate in extension of the tubular extensions. A member operates in conjunction with the tubular extensions to a wall of the afore-mentioned bars for the mounting of the guide.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED PATENT APPLICATIONS The present application claims the benefit of U.S. Provisional Application No. 60/948,175, filed Jul. 5, 2007, which is incorporated by reference herein in its entirety. BACKGROUND The present disclosure relates generally to the field of partitions used in, for example, restrooms, to provide privacy for persons using the restroom. More specifically, the present disclosure relates to a “no-sight” partition system that inhibits or prevents a line of sight from being established from one side of a partition to another side of a partition and may include universal construction. Various types of establishments, such as office buildings, educational facilities, recreational facilities, shopping areas, etc. typically provide areas such as restrooms, showers, changing rooms, or any of a wide variety of other types of facilities where users normally require or desire some level of privacy. In order to provide such privacy, partitions or partition systems may be used to provide areas or stalls (e.g., a bathroom stall, a shower stall, etc., a changing room, etc.) for private, individual use. A partition system typically includes one or more walls/panels, doors, and pilasters. The partition system may include generally flat panels that are fastened in a suitable fashion and provided with locks to enable people to enter/exit the stalls and ensure that others do not enter or see into a particular stall when the stall is in use. SUMMARY According to one embodiment, a partition system comprises a first pilaster and a door coupled to the first pilaster and rotatable from a closed position to an open position. The door is configurable in a first configuration wherein the door is rotatable from the closed position to the open position in a first direction and prevented from rotating in a second direction from the closed position, the second direction opposite the first direction. The door is further configurable in a second configuration wherein the door is rotatable from the closed position to the open position in the second direction and prevented from rotating in the first direction from the closed position. The door may be coupled to the first pilaster to define a seam and prevent a line of sight from being established through the seam. According to another embodiment, a partition system comprises a pilaster comprising an extending portion having a first side and a second side opposite the first side, and a door configured to engage the extending portion when the door is in a closed position. The door is configurable in a first installed orientation where the door engages the first side when in the closed position. The door is further configurable in a second installed orientation where the door engages the second side when in the closed position. The door may engage the extending portion to define a seam and prevent a line of sight from being established through the seam. According to yet another embodiment, a partition system comprises a first pilaster having a recess, a door, the door rotatably coupled to the first pilaster, a portion of the door configured to be received within the recess, and a second pilaster configured to engage the door when the door is in a closed position. The door is coupleable to the first pilaster in a first orientation such that the door rotates from the closed position to a first open position in a first direction. The door is further coupleable to the first pilaster in a second orientation such that the door rotates from the closed position to a second open position in a second direction, the second direction being opposite the first direction. The door and the first and second pilasters are configured to prevent a line of sight from being established from a first side of the door to a second side of the door at the interface of the door and the first pilaster and at the interface of the door and the second pilaster. According to yet another embodiment, a partition system comprises a door comprising a curved portion and a pilaster comprising a recess. The door is rotatably coupled to the pilaster such that at least a portion of the curved portion is received within the recess when the door is in a closed position. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a facility including a number of partitioned areas or stalls according to an exemplary embodiment. FIG. 2 is a front view of a partition with a door in a closed position according to an exemplary embodiment. FIG. 3 is a perspective view of the partition of FIG. 2 with the door in an open position according to an exemplary embodiment. FIG. 4 is a cross-section view of the partition of FIG. 2 with the door in a closed position according to an exemplary embodiment. FIG. 5 is a cross-section view of the partition of FIG. 2 with the door in an open position according to an exemplary embodiment. FIG. 6 is a cross-section view of the partition of FIG. 3 with the door in an open position according to an exemplary embodiment. FIG. 7 is a partial exploded view of the partition of FIG. 2 according to an exemplary embodiment. FIG. 8 is a cross-section view of a partition according to an exemplary embodiment. FIG. 9 is a cross-section view of a partition according to an exemplary embodiment. FIG. 10 is a cross-section view of a partition according to an exemplary embodiment. FIG. 11 is a cross-section view of a partition according to an exemplary embodiment. FIG. 12 is a cross-section view of the partition of FIG. 11 in an open position according to an exemplary embodiment. FIG. 13 is a cross-section view of a partition according to an exemplary embodiment. Before explaining a number of exemplary embodiments in detail, it is to be understood that the subject matter disclosed herein is not limited to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The subject matter is capable of other embodiments or being practiced or carried out in various ways. It is also to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS A partition system typically includes one or more walls/panels, doors, and pilasters. The partition system may include generally flat panels that are fastened in a suitable fashion and provided with locks to enable people to enter/exit the stalls and ensure that others do not enter or see into a particular stall when the stall is in use. One problem associated with the use of conventional partition system is that even though the door may be closed and securely locked, gaps may still exist between partition system members, and more particularly, at the “seams” between the door and the adjacent partition portions (i.e., the area where the door ends and the adjacent partition portion begins), where it may be possible to see into an individual stall from the outside area. This is particularly undesirable where privacy concerns are of high importance (e.g., with a bathroom stall). Another problem associated with manufacturing, storing, and installing many conventional partition systems is that they have doors that open in only one direction and require separate component parts to provide a door that swings in the opposite direction (e.g., relative to the interior of a stall). Accordingly, it would be advantageous to provide a no-sight partition system that prevents others from seeing into, for example, a bathroom stall, when the door is closed. Further, it would be advantageous to provide a universal no-sight partition system that may be configured (reconfigured, adapted, etc.) such that the door may be opened either toward or away from the interior of the stall, or with a left-handed or right-handed door swing, while minimizing the number of components for the partition. Referring now to FIG. 1 , according to an exemplary embodiment, a facility (e.g., a restroom, shower, changing room, etc.) shown as restroom 10 has a plurality of partitioned areas each shown as a stall 12 (e.g., a restroom stall, a changing room stall, a shower stall, etc.). Stall 12 is intended to provide security and privacy to users of stall 12 such that others may not enter or see into stall 12 when stall 12 is in use. While FIG. 1 shows stall 12 as a restroom stall, it should be understood that according to various alternative embodiments, stall 12 may be used in any of a variety of applications (e.g., showers, dressing rooms, etc.), and the teachings herein extend to all such applications. As shown in FIG. 1 , a number of stalls 12 may be provided adjacent one another with each stall having an interior 14 . Interior 14 is generally defined by one or more sidewalls 16 and a partition 18 . According to an exemplary embodiment, partition 18 includes one or more doors 20 that are provided between pilasters 22 , 24 (e.g., faces, stiles, dividers, panels, wall members, etc.). For purposes of this disclosure, partition 18 will refer to door 20 and pilasters 22 , 24 . However, it should be understood that partition 18 may include a number of doors and/or pilasters. One or more stalls 12 may have one or more sidewalls in common (e.g., as shown in FIG. 1 , several sidewalls act as a sidewall for two different stalls). Further, the walls of restroom 10 or other structures may provide at least one sidewall for stall 12 . According to one embodiment, door 20 is attached via a hinge 26 to pilaster 22 such that door 20 may be rotated from a closed position (see FIG. 2 ) to an open position (see FIG. 3 ) such that persons may enter and exit stall 12 . Hinge 26 may be any suitable hinge assembly (e.g., a pin and socket, piano hinge, etc.). A handle and/or a lock or latch mechanism may also be provided such that users may lock door 20 in a closed position from interior area 14 . Referring to FIGS. 2 and 3 , door 20 and pilasters 22 , 24 are shown in greater detail. According to one embodiment, when door 20 is in the closed position as shown in FIG. 2 , a first seam 28 is created between pilaster 22 and door 20 and a second seam 30 is created between pilaster 24 and door 20 . According to an exemplary embodiment, door 20 and pilasters 22 , 24 are designed such that door 20 and pilasters 22 , 24 are substantially coplanar when door 20 is closed. As discussed in further detail below, a single door 20 may be installed such that it may open in either an “out-swing” fashion (e.g., such that the door swings away, or out, from interior 14 when opened, as shown in FIG. 3 ) or in an “in-swing” fashion (e.g., such that the door swings in toward interior 14 when opened, as shown in FIG. 5 ). This “universal design” is an advantage over many conventional partition systems that may be installed in only one of the out-swing or in-swing configurations, because the present design minimizes the number of parts needed to accommodate various different partition applications, thereby reducing material costs and simplifying the installation process. Referring now to FIGS. 4-12 , various interfaces between door 20 and pilasters 22 , 24 are shown in greater detail. Referring to FIG. 4 , partition 18 is provided such that arrow A represents a line of sight from outside a stall (e.g., from the outside looking in). Partition 18 is a “no-sight” partition in that door 20 and pilasters 22 , 24 close at seams 28 , 30 such that there is no line of sight through seams 28 , 30 when door 20 is in the closed position. When a user fully closes door 20 and is within interior area 14 , no one from outside stall 12 may see into interior portion 14 through seams 28 , 30 . This “no-sight” feature is an advantage over many conventional partitioning systems that leave gaps at the seams, thereby potentially compromising the privacy and security of users. As shown in FIGS. 4-6 , door 20 may include a first member or lip 32 (e.g., a rail, extension, projection, etc.) that according to one embodiment, may extend along a portion or all of the length of door 20 . Lip 32 on door 20 may be configured to engage a corresponding second member or stop 34 (e.g., an extension, rail, etc.) provided on pilaster 24 . According to one embodiment, stop 34 may be formed by two grooves 36 , 38 (see FIG. 5 ) that are formed into pilaster 24 and may be generally symmetric about a mid-section of pilaster 24 . As shown in FIG. 4 , when door 20 is closed, lip 32 overlaps with stop 34 along the length of seam 30 such that it is not possible to see “through” partition 18 (e.g., in the direction represented with arrow A in FIGS. 4-6 , between adjoining or adjacent panels or members of the stall). Furthermore, the overlap of lip 32 and stop 34 permit door 20 to be opened in only a single direction. For example, as shown in FIG. 5 , door 20 is in the in-swing position, while as shown in FIG. 6 , door 20 is in the out-swing position. Door 20 and pilaster 24 are universal in design and may be moved from the in-swing position to the out-swing position by removing door 20 from partition 18 , flipping door 20 over (e.g., such that the top edge becomes the bottom edge), and reinstalling door 20 . Door 20 may further include a contoured portion 40 (e.g., a convex portion, a curved portion, etc.) that rotates relative and adjacent to a correspondingly contoured portion 42 (e.g., a concave portion, a curved portion, etc.) on pilaster 22 . Contoured portions 40 , 42 are designed such that in contrast to right-angled door and pilaster members, where a gap may permit a line of sight through partition 18 at seam 28 , no line of sight may be established at seam 28 because of the corresponding contoured portions 40 , 42 of door 20 and pilaster 22 . As shown in FIGS. 5 and 6 , contoured portions 40 , 42 are universally designed such that they may be used in either the in-swing or out-swing positions. According to another exemplary embodiment, partition 18 is configured to facilitate changing partition 18 from having a right-handed swinging door to having a left-handed swinging door. For example, as shown in FIG. 3 , door 20 is in the left-handed position, such that it swings about hinge portion 26 along the left edge of door 20 (as viewed from outside a typical stall). Partition 18 may be reconfigured to provide a right-handed door by exchanging the positions of pilasters 22 and 24 and reinstalling door 20 in a rotated position (e.g., such that the left edge becomes the right edge as shown in FIG. 3 ). This may be particularly advantageous in applications where flipping door 20 is not possible (e.g., in cases where the top and bottom edges of door 20 are unique from each other and are not functionally interchangeable). According to various exemplary embodiments, partition 18 may be assembled in a variety of in-swing/out-swing and left-handed/right-handed configurations to suit various applications. While FIGS. 4 and 5 show specific embodiments of partition 18 and the interfaces between door 20 and pilasters 22 , 24 , it should be understood that a wide variety of configurations may be used to provide a no-sight partition such as partition 18 . FIGS. 8-13 shows various alternative configurations for partition 18 . For example, referring to FIG. 8 , door 20 may include a generally triangular-shaped projection 44 intended to engaged one of two correspondingly shaped surfaces 46 , 48 . As shown in FIG. 9 , rather than contoured portion 40 having a smooth radius, a polygonal profile may be provided such as a portion 50 that maintains the no-sight and universal characteristics of partition 18 discussed in greater detail above. FIG. 10 illustrates a door and pilaster configuration where door 20 may be installed in and operate in only one of the in-swing and out-swing positions. Referring to FIGS. 11 and 12 , yet another embodiment of a partition 18 is illustrated. As shown in FIGS. 11 and 12 , a door 120 includes a contoured portion or lip 134 and a contoured portion 140 . Portions 134 and 140 are similarly shaped such that only a single pilaster configuration, such as a pilaster 126 having two contoured portions 142 , is required to engage both sides of door 120 . This further reduces the number of components involved in partition 18 and the associated material costs. Referring to FIG. 13 , another embodiment of partition 18 is illustrated according to another exemplary embodiment. As shown in FIG. 13 , door 20 may include contoured portion 40 on both edges (e.g., left and right edges as facing door 20 in an installed position). Pilasters 22 and 24 may each include corresponding contoured portions 42 on one or both sides or edges. In this manner, both door 20 and pilaster 22 , 24 may be generally symmetrical in shape. Furthermore, pilasters 22 , 24 may be interchangeable and in some embodiments, may be identical. According to various other alternative embodiments, other component configurations (e.g., shapes, sizes, etc.) may be used in forming partition 18 . Furthermore, the locations of the various interface portions (e.g., the lip, stop, contours, etc.) may be varied (e.g., reversed, etc.). For example, a single pilaster may be configured to have two stop portions, two hinge portions, one stop portion and one hinge portion, etc., depending on the particular application. It should be understood that the FIGURES are not shown to scale and that the sizing (e.g., length, width, etc.) of the various components (e.g., the door, pilasters, etc.) may be varied to suit particular applications. Further, it is important to note that for purposes of this disclosure, the term “coupled” shall mean the joining of two members directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate member being attached to one another. Such joining may be permanent in nature or alternatively may be removable or releasable in nature. Such joining may also relate to mechanical, fluid, or electrical relationship between the two components. It is also important to note that the construction and arrangement of the elements of the no-sight partition as shown in the exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. Accordingly, all such modifications are intended to be included within the scope of the present disclosure as defined in the appended claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and/or omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the spirit of the present disclosure as expressed in the appended claims.	A partition system includes a first pilaster and a door coupled to the first pilaster and rotatable from a closed position to an open position. The door is configurable in a first configuration wherein the door is rotatable from the closed position to the open position in a first direction and prevented from rotating in a second direction from the closed position, the second direction opposite the first direction. The door is further configurable in a second configuration wherein the door is rotatable from the closed position to the open position in the second direction and prevented from rotating in the first direction from the closed position. The door is coupled to the first pilaster to define a seam and prevents a line of sight from being established through the seam.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION The present invention relates to drilling subsea wells, and typically from a floating drilling rig. More particularly, this invention relates to a subsea riser disconnect equipment and techniques for sealingly connecting a lower riser extending downward into and fixed within a subsea well bore with an upper riser extending downward from the floating drilling rig, such that the upper riser may be disconnected from the fixed lower riser during adverse weather or other rig move-off conditions. BACKGROUND OF THE INVENTION Subsea wells are increasingly important to hydrocarbon recovery operations. Numerous land-based wells have been drilled, but the percentage of hydrocarbons recovered from land-based wells is steadily decreasing in some parts of the world. Jack-up rigs have been used offshore for decades to drill wells subsea to recover oil, but jack-up rigs are practically limited to drilling operations in relative shallow water of several hundred feet. As water depth increases other drilling rig options may be required to facilitate drilling and well completion operations. In addition to an increase in the number of off-shore wells being drilled, in more recent years an increasing number of wells are being drilled in deeper water and at increasing costs. Accordingly, drilling from offshore rigs, e.g., drilling ships, semi-submersibles, jack-ups, drilling barges or submersible rigs has significantly increased in recent years. The economics associated with drilling offshore remains, however, a primary reason why more wells are not drilled offshore. Particularly, in drilling exploratory wells where financial risk and commercial hydrocarbon uncertainty may severely impact the economics for drilling such wells, costs and may be more critical in determining whether any wells are drilled at all, and how many may be drilled. The majority of offshore or marine drilling rigs utilize riser sections as the outermost tubular between the rig and the seafloor, with the riser sections typically being bolted, clamped, mechanically fixed by dog-type latch mechanisms or otherwise connected. Riser sections conventionally include hydraulic lines spaced outwardly of the assembled riser pipe for operating the blow out preventer (BOP) and subsea ram stack located above the mud line. During an emergency or in anticipation of adverse weather conditions, the subsea BOP may be closed and the rams hydraulically activated to seal off the well bore. Prior to closing the rams, the drill pipe may be threadably disconnected above or below the BOP stack utilizing a back off tool or back off method, or the drill pipe may be sheared by the shear ram assembly. In some applications, acoustically or electrically activated subsea accumulators have been used to replace the hydraulic lines which commonly are run along side the riser pipe. The subsea BOP stack assembly used during deep water drilling operations may contribute significantly to the cost of drilling a well and a substantial amount of expensive rig time may be expended running in and removing the riser pipe sections and related well control equipment. The above disadvantages associated with drilling from floating drilling rigs have long been known. Accordingly, some drilling or operating companies may recommend “riser-less drilling” for certain deep water applications. A subsea pump may be provided to return the drilling fluid to the surface in a separate flow line. Riser-less drilling still has to contend with the high cost of the BOP stack and hydraulic operation of this equipment. Several wells have been successfully drilled from a floating drilling rig, while using a riser, wherein the BOP is placed on the drilling rig rather than subsea. To date, however, these wells practically are limited to geographic areas where and/or seasons when there is a reduced likelihood of adverse weather conditions which would require the floating drilling rig to relatively quickly disengage a portion of the riser, e.g., an upper riser from the lower riser. In these applications, however, elimination of the subsea BOP stack may result in significant cost savings when drilling a well. Further savings may be realized by using conventional threaded casing for a riser rather than flange-type riser pipe sections. Less area on the drilling vessel is required to store casing having the same nominal diameter as the riser pipe sections since conventional riser pipe sections include both flanges and hydraulic lines which are eliminated when using casing as the riser. Typically, subsea BOP stacks are installed on the riser string. The BOP stack may be required to provide a subsea method of isolating a lower portion of the riser and well bore from the riser above the BOP stack. Stress in the riser typically includes the weight of the riser and the weight of the subsea BOP. Subsea BOP stacks may weigh in excess of 400,000 pounds. The weight of the BOP stack plus the weight of a riser sufficiently strong enough to deploy such stack and meet operational requirements necessitates that risers are inherently heavy pieces of equipment which may exert high levels of stress and strain on the drilling and on the riser sections. These effects may be even more pronounced in deep water applications. In deep water installations, installation of a typical riser system may require calm weather and well in excess of a week to install, and in excess of a week to retract. In addition to the subsea riser and BOP stack, electrical and hydraulic umbilical lines are typically deployed concurrently, to control and operate the BOP stack, choke and kill line valves, and hydraulic disconnects if present. Deployment and recovery of this equipment and the rig time involved all contribute significantly to well costs, as daily rental rates for semi-submersible drilling rigs may exceed $240,00 per day. Premature disconnection of a portion of the riser can likewise be expensive and time consuming, such as may be necessary in advance of hostile weather conditions, broken mooring chain or slipping mooring anchor. If drill pipe is in a well bore and it becomes necessary to seal the interior of the well bore, pipe rams or shear rams in the BOP stack may be closed on the drill string to confine pressure and fluid within the well bore. In the event it becomes necessary to disconnect an upper portion of the drill pipe from a lower portion of the drill pipe, the drill pipe may be unthreaded at a tool joint, or cut with a chemical cutter or explosive charge. If pipe is stuck, the free point may be estimated by a free point calculation technique. Each of these disconnect methods requires time to determine free points, deploy appropriate tools on wire line, such as a “string shot,” a free-point tool, a chemical cutter or jet-shot explosive charge. Multiple attempts and re-calculations may be required. The process can be time consuming and frustrating and may still result disconnecting at an undesirable disconnect point. Reconnecting after disconnecting can be even more exasperating, time consuming and expensive, and even impossible. Disadvantages of the prior art are overcome by the present invention. An improved method of drilling from a floating drilling rig is hereinafter disclosed. A subsea riser disconnect is provided for connecting and disconnecting a lower riser from an upper riser. SUMMARY OF THE INVENTION This invention provides means and equipment for relatively quickly, physically disconnecting a floating drilling rig from a subsea well in a manner that may be operationally and economically more efficient than prior art equipment and techniques. In the event hostile weather conditions, rig conditions or well conditions threaten the safety or operating capabilities of an offshore drilling rig or work over vessel, the rig or vessel may be disconnected and moved out of harms way. The rig may later return to the well location and reconnect to the disconnected members. This invention provides means and equipment for installing a riser system and well control system which may provide for a more cost effective offshore drilling and/or work over operations than is available under prior art. Such improvements may reduce the costs to find, develop and produce hydrocarbons. In one embodiment, this invention generally includes three primary components: a) a maritime or subsea riser disconnect for disconnecting and reconnecting an upper portion of the riser with a lower portion of the riser, b) a subsea riser valve for sealing off an interior of a well bore below the riser valve, and c) a drill pipe disconnect for disconnecting and reconnecting an upper portion of the drill pipe with a lower portion of the drill pipe. Subsea Riser Disconnect A preferred embodiment of a subsea riser disconnect includes an apparatus and means which disconnects an upper portion of the subsea riser from a lower portion of the riser, through axial movement of the upper riser relative to the lower riser. The upper riser and the lower riser may be collectively referred to as a riser system. The subsea riser disconnect may be positioned at substantially any point within the riser system, e.g., between the drilling rig and the mud line. The subsea riser is preferably accessible to either a remotely operated vehicle (ROV) or a diver, in order that a riser disconnect lockout device may be operated if needed. The subsea riser disconnect may facilitate placing the blow out preventer and well control stack (BOP) either on the rig or suspended from but relatively near the rig. A preferred embodiment of a riser disconnect may include a male disconnect member secured to the lower end of the upper riser, and a female disconnect member secured to the upper end of the lower riser. The male disconnect member may include a seal mandrel and seal elements for providing a hydraulic seal between the male disconnect member and female disconnect member. The male disconnect member may also include a collet mechanism to facilitate latching and unlatching the male and female disconnect members. A lockout device may be included to prevent inadvertent actuation of the subsea riser disconnect, such as during initial installation of the riser disconnect and riser system. Manipulation of the lockout may be externally performed, such as by ROV, diver or otherwise. The female riser disconnect member may include a seal bore receptacle for sealingly receiving the seal mandrel within the seal bore receptacle, and a circumferential collet groove may be included in an inner surface of the female riser disconnect for engaging collet dogs. A conical shaped entry guide may be included on an upper end of the lower riser disconnect member to guide the male disconnect member into the female disconnect member during subsea connection of the male and female disconnect member. Manipulation of the riser disconnect latch may be performed by axial motion or reciprocation of the upper riser relative to the lower riser. (The terms “axial reciprocation, reciprocation, axial motion, axial, or similar variations of these terms, as used herein may be defined to be substantially synonymous, and include linear displacement of a first component relative to a second component, substantially along a common linear axis, in a first direction and/or second direction, but not necessarily consecutively in both directions during a single manipulation period.) The latching collet mechanism of the riser disconnect may be manipulated between the collet latch position and the collet unlatch position by alternately applying tension and releasing tension in the riser disconnect by the drilling rig. In an initial installation, the riser latch mechanism, including the collet mechanism, may be positioned in the collet latch position. After the riser system is installed and cemented in position within the well bore, tension may be applied to the riser system at the riser disconnect to securely retain the latched engagement between the male and female disconnect members. To disconnect the male and female disconnect members, such as in advance of an approaching storm, tension in the riser disconnect may be relaxed allowing the male disconnect member to move axially downward relative to the female disconnect member, thereby unlatching the collet mechanism. The upper riser may be subsequently raised, separated from and suspended above the lower riser. The rig may then be moved and/or the upper riser recovered to the rig. To reconnect the riser disconnect, the male disconnect member may be guided by the entry guide into engagement with the female disconnect member and the collet mechanism re-latched. Tension may be applied and maintained in the riser system to retain the latched configuration during operations until it is desirable to again disconnect the riser disconnect system. Upon completion of well work operations, the female disconnect member with the male disconnect member (plus a subsea riser valve, if run) may be typically recovered together by normally cutting the riser below the mud line with either an explosive charge, a chemical cutter or a mechanical cutter. If desired, the riser disconnect and lower riser may be drilled into position in the sea bed while the well bore for the lower riser is being drilled. This may be accomplished by a number of means, for example preferably by positioning the lower riser on the sea bed with a riser disconnect and portions of an upper riser attached or to be attached substantially during drilling operations, and running a string of drill pipe, a drill bit and/or an under reamer bit through the deployed riser assembly and rotating the riser string with the bit while drilling the lower riser into the seabed. Alternatively, the drill string may substantially swivel or rotate within the riser while the riser may not rotate or may rotate independently from the drill string, while drilling the lower riser into the sea bed for cementing and permanent placement of the lower riser. The drill bit and drill string may then be retrieved back to the rig. Those skilled in the art of well drilling operations will appreciate that there are a number of other means for drilling in the lower riser. An alternative embodiment for the riser disconnect provides non-rotational engagement grooves in order to rotate the riser with the drill string. In an another alternative embodiment, the upper riser may include the female disconnect member and related components, while the lower riser provides the male disconnect member and related components. An alternative embodiment may also provide the seal members within the female member while the male seal member provides a substantially smooth sealing surface on a mandrel. It is an object of the present embodiment to improve the economics of drilling, completion and work over operations from an offshore rig by providing a more economical method of equipment optimization and use. An embodiment provides apparatus and means for placing the wellhead and BOP system substantially on the rig. In a preferred installation, a riser system may be utilized which employs riser joint connections secured by means and apparatus other than by flanges and bolting, such as a threaded riser consisting of joints of well casing, or a groove locked connection. Such equipment usage and arrangement may also save a considerable amount of time in retracting and deploying the upper riser. In addition, a flex joint may be provided either above or below the riser disconnect to accommodate riser angular displacement. It is also an object of this embodiment to provide apparatus and means to relatively quickly disconnect an upper riser from a lower riser to facilitate moving the rig out of harms way. This embodiment provides a riser disconnect system which may be actuated by merely reciprocating the upper riser relative to the lower riser. It is further an objective of this embodiment to provide a riser disconnect apparatus which may be easily and reliably manipulated from the rig. Manipulation of the riser disconnect between the riser latch position and the riser unlatch position may be performed by simple axial reciprocation of the riser disconnect from the rig. Moving the BOP stack near the rig may also assist in economic riser deployment and recovery. It is a feature of this preferred embodiment to provide a riser disconnect system which may be reconnected after disconnecting the male and female disconnect members. The riser disconnect system of this embodiment may be repeatedly connected and disconnected. It is another feature of this embodiment that the riser disconnect may be manipulated between the connected and disconnected positions without subsurface hydraulic and/or electrical umbilical lines. Although such lines may optionally be employed for other purposes, the riser disconnect does not require them. It is also a feature of this embodiment that the riser disconnect system may be locked in the riser latch or unlocked from the riser latch position. The riser system, including the riser disconnect may be installed while the riser disconnect is locked in the latched position, and after installation the riser disconnect may preferably remain unlocked, while riser tension maintains the disconnect in a latched configuration. These advantages may enhance deep water operations by facilitating employment of an improved, more cost effective riser and drilling system which may save considerable time and costs. The subsea riser disconnect may provide for placing the BOP stack on or suspended just below the rig or drill ship, thereby effectively eliminating placing the BOP stack on the ocean floor. By minimizing the number of subsurface hydraulic and electric umbilical lines, connectors, and kill and choke lines, several days of rig time may be saved. The preferred drilling equipment configuration and alternative embodiments thereof, as disclosed herein, may be particularly applicable for drilling and completing exploratory or other wells where well costs are a key consideration and where the well may not be intended for production after well testing. It is also a feature of this embodiment that the riser disconnect system may be employed with re-entry risers as well as drilling and completion risers. Although the preferred embodiment is illustrated generally in terms of use with a drilling riser installation, the concepts and apparatus for riser disconnect manipulation by axial reciprocation methods may be applied equally well to risers used in completion and re-entry operations following well completion. Subsea Riser Valve A preferred embodiment of a subsurface riser valve includes an apparatus and methods for sealing the interior of a well bore, below the riser valve, through axial movement of the riser above the riser valve (generally, the upper riser) relative to the riser below the riser valve (generally, the lower riser). The subsea riser valve may be positioned at substantially any point along a riser system, preferably below the riser disconnect such that the riser valve may be closed in conjunction with or prior to disconnection of a riser disconnect. The subsea riser valve may also provide a subsea method of well control, such that the BOP stack may be positioned on the rig. A preferred embodiment of the subsurface riser valve provides for the riser valve as a distinct, stand-alone piece of equipment which may be employed separately or in combination with riser and/or drill pipe disconnect apparatus. The riser valve is preferably used in combination with the riser disconnect, such that the riser valve is positioned below the riser disconnect in order that the interior of a lower riser and well bore below the riser valve may be hydraulically isolated and confined. The lower end of a riser valve may be sealingly connected to the upper end of a lower riser, a well casing, a well head or other subsea component. The upper end of the subsea riser valve may be directly or indirectly secured to the lower end of the subsea riser disconnect. The subsea riser valve includes a valve housing enclosing a valve sealing member, and a valve actuation mandrel telescopically extending from the upper portion of the riser valve. A linkage or connector may moveably connect the valve sealing member and the valve actuation mandrel. The riser valve may be biased closed and may be opened in response to axial tension in the riser system. A lockout device similar to the lockout device described on the riser disconnect above, may be included with the riser valve apparatus, to lock the riser valve in either the valve opened or valve closed positions. The riser valve may be locked in the opened position during installation of the riser system to allow the riser to fill with fluid and to allow circulation of fluids or slurries through the string prior to applying tension in the valve system. When the riser valve and riser system are properly positioned, installed and cemented, tension may be exerted on the riser valve to maintain the valve sealing member in the valve opened position. Prior to closing the valve sealing member, components within the through bore of the riser valve may be removed from within the through bore of the riser valve, such that the valve sealing member may freely move between the valve closed and valve opened positions. It is an objective of this embodiment to provide an apparatus and means for sealing the interior of a riser and well bore below the riser in response to axial motion of the upper riser string. To close an opened valve sealing member, axial tension in the riser system may be relaxed such that the weight of the riser and the resulting closing biasing force may close the riser valve, effectively sealing the well bore below the riser valve. To open the riser valve, axial tension may be applied to the upper riser and valve actuation mandrel sufficient to overcome the riser weight and closing bias force. The riser valve may be opened and closed repeatedly as needed during well operations. It is an object of this embodiment that the riser valve may be used in conjunction with the riser disconnect to provide a mechanically actuated riser disconnect and well control system for connecting a drilling rig to a subsea well bore. Such mechanically actuated system may assist in facilitating placing the BOP stack and related well control equipment on or near the drilling rig. Such arrangement may significantly decrease well costs by eliminating hydraulic and/or electrical umbilical lines between subsea equipment and the rig. Concurrent and subsequent axial movement of the riser may also unlatch and disconnect the upper riser from the lower riser. The rig and upper riser may thereafter be removed from the situs of the well, while the subsea well control valve remains to contains well pressure and fluids within the well bore. It is also an object of this embodiment to provide a subsea riser valve which may be manipulated between the opened and closed positions without hydraulic or electrical lines. Mechanical movement within the valve mechanism is provided by axial movement of the riser system, thereby effectively eliminating the need for hydraulic or electrical actuation of the valve sealing member. It is a feature of this embodiment that the riser valve provide a full bore opening through bore. The preferred riser valve, including the valve sealing member may provide an ID that is not less than the minimum ID of either or both of the upper riser and lower riser. It is another feature of this embodiment that the preferred riser valve may be provided as a separate, stand alone device, such that the riser valve may be used alone in a riser system, or a riser disconnect may be combined with a stand-alone riser valve and/or other separate devices. Alternatively, the riser valve may be integrated into a common housing with a riser disconnect apparatus. Both apparatus may be compatible for use as an integrated tool combining both the riser valve and the riser disconnect in a common housing or body, as both may be compatibly manipulated by axial tension applied at the drilling rig. It is also a feature of this embodiment that the riser valve may be installed inverted from the preferred orientation described above, such that the valve actuation mandrel is connected to the lower riser, casing or well head. In either the preferred or an inverted embodiment, the riser valve may be manipulated with tension in the upper riser. An additional feature of other embodiments of this invention is that the riser valve components may be varied such that the valve sealing member may be of a type other than a ball type sealing member, such as plug type rotational cylinder members, or gate type sealing members, or flapper type sealing members. Alternative embodiments for a riser valve may be configured for manipulating each of these types of sealing members from axial movement of the upper riser relative to the lower riser. Drill Pipe Disconnect Apparatus and method are disclosed for connecting and disconnecting an upper portion of a drill pipe string above a drill pipe disconnect apparatus from a lower portion of a drill pipe string below the disconnect apparatus. The drill pipe disconnect may be positioned at substantially any point along the drill string wherein it may be convenient or desirable to disconnect a portion of the drill pipe string from the remainder of the string. Such disconnection may be required in conjunction with disconnecting a subsea riser disconnect, and/or in conjunction with closing a subsea riser valve, such as may be desirable in advance of relocating the rig due to approaching threatening weather. The drill pipe disconnect is preferably used in conjunction with the subsea riser disconnect and/or the subsea riser valve. Prior to closing a riser valve and/or disconnecting a riser disconnect, rather than pull the entire string of drill pipe above the riser valve, it may be prudent to temporarily abandon the portion of the drill pipe string which is below the riser valve and the drill pipe disconnect. In such event, the drill pipe disconnect may be disconnected at a point below the riser valve, and the upper disconnected portion of drill pipe pulled up to above the riser valve, such that the riser valve may be closed and the riser disconnect subsequently disconnected. The drill pipe disconnect may be selectively operable to mechanically disconnect or connect the upper and lower portions of a drill pipe string, in response to movement of a latch mechanism, while also providing axial and rotational strength commensurate with the strength of the drill pipe in use. Non-rotational engagement components may be included within the drill pipe disconnect to carry rotational stresses in the drill string. A preferred embodiment of a drill pipe disconnect apparatus may generally include a male drill pipe disconnect member and a female drill pipe disconnect member. The male disconnect member may include a collet mechanism to latch and unlatch the male and female disconnect members. A latch sleeve may be included, which is movable between a collet latch position and a collet unlatch position. When the latch sleeve is in the collet unlatch position, the male drill pipe disconnect member may be released from engagement with the female drill pipe disconnect member. The male and female disconnect members of the drill pipe disconnect may be secured within a drill pipe string by connections provided on each end of the drill pipe disconnect. In a preferable embodiment, the upper end of the male disconnect may include a threaded box type tool joint, while the lower end of the female disconnect may include a threaded pin type tool joint. A preferred method of operation for the drill pipe disconnect generally includes providing and operating a first assembly and a second assembly, which is a modification of the first assembly. The first assembly may typically be employed for an initial drill pipe disconnect installation. Thereafter, subsequent to disconnecting the drill pipe assembly and recovering the male drill pipe disconnect member to the rig, the second assembly may be installed. The second assembly is provided by substituting a male reconnect member for the male disconnect member, to reconnect the male reconnect member with the female disconnect member. Thereafter, if desired the male reconnect member and the female disconnect member may be re-unlatched from one another. The first assembly for the drill pipe disconnect may be installed in a drill pipe string, such that the collet mechanism and latch sleeve are in the collet latch position. A shear pin may secure the position of the latch sleeve within a male disconnect housing, in the collet latched position. The string of drill pipe including the drill pipe disconnect may be repeatedly inserted into and withdrawn from a well bore as needed, such as when “tripping pipe,” with the drill pipe disconnect apparatus threadably secured within the drill string. In the event it becomes desirable to disconnect the drill pipe disconnect and temporarily or permanently abandon a lower portion of drill pipe within the well bore, an unlatching ball or other closure device may be dropped through the upper portion of drill pipe, from the rig floor. The unlatching ball may sealingly seat on the unlatching seat such that hydraulic pressure may be applied to the drill string from the rig to cause the latch sleeve to shear the shear pin and move downward to a position where the collet dogs may unlatch from engagement with the female disconnect member. The male drill pipe disconnect member may then be telescopically withdrawn from the female disconnect member, and the male disconnect member and upper portion of drill pipe withdrawn to the rig. To reconnect the male disconnect member with the female disconnect member, the male second assembly of the male disconnect member may be provided with a positionable latch sleeve that includes two unlatch grooves, shear pins that provide for two shearing actions, a latching seat and an extension tube on the latch sleeve. The male disconnect member may subsequently be engaged with the female disconnect member in the well bore. A latching ball may then be dropped through the drill pipe string for sealingly seating on a latching seat in the latch sleeve. The latching seat may be secured within the latch sleeve by shear pins. Hydraulic pressure may be applied within the drill string, sufficient to shear the double shear pins at a first shear point. The latch sleeve may then move downward from a collet unlatch position to a collet latch position, such that the male and female disconnect members are again securely latched together. Hydraulic pressure within the drill string may be further increased to until the shear pins which secure the latch seat within the latch sleeve are sheared, allowing the latch seat and latching ball to be ejected downward from within the latch sleeve. The extension tube on the latch sleeve may receive or catch the ejected latch seat and latching ball. The extension tube may provide a plurality of ports to hydraulically interconnect the upper and lower portions of the interior of the drill pipe. A hydraulic conduit is thereby provided through the drill pipe through bore such that fluid may be circulated through the upper and lower portions of the drill pipe string. The latch seat and latching ball may remain within the extension tube. As an alternative, instead of shearing the latch seat pins and ejecting the latch seat and latching ball and receiving the latch seat and latching ball within the extension tube, the latch ball may be recovered to the surface. Fluid may be circulated down the drill pipe/casing annulus and back up through the drill bit and drill pipe to reverse flow the latching ball back to the surface of the rig. In the preferred embodiment, to re-unlatch the male drill pipe disconnect from the female drill pipe disconnect, a re-unlatching ball may be dropped for sealingly seating on a re-unlatching seat. Hydraulic pressure applied within the drill pipe through bore may shear the double shear pins at a second point and allow the latch sleeve to move downward to a re-unlatch position, wherein the male disconnect member may be withdrawn from the female disconnect member and recovered to the rig. For subsequent re-engagement, the male disconnect member may be again re-dressed as described above for reconnection. The drill pipe disconnect apparatus and/or method may be utilized in either an off-shore installation or a land based installation. In a land based installation, the drill pipe disconnect may provide for a disconnect point in the drill pipe string, such as may be desirable to provide above a geologic trouble spot or near a casing seat above an open hole section. It may be desirable to provide a convenient disconnect device at a point in the drill string where backing off or disconnecting otherwise may be difficult or impossible to achieve, particularly in deep wells or along long horizontal well bore sections. It is an object of this embodiment to provide a method of operation and an apparatus for disconnecting an upper portion of a drill pipe string from a lower portion of the drill pipe string in a quick, reliable manner. The preferred disconnect method and apparatus disclosed herein facilitates providing a relatively simple and reliable disconnection point within a drill pipe string. Some of the components and mechanisms relied upon for operation of this embodiment are recognized as generally reliable mechanisms, such as a collet mechanism, shear pinned components, and ball and seat type hydraulic seals. It is also an object of this embodiment to provide a drill pipe disconnect apparatus and method which may be manipulated without relying upon back-off tools, back-off methods, external manipulation devices or destruction of drill pipe to disconnect. This embodiment provides method and apparatus for disconnecting an upper section of a drill pipe string from a lower section of the drill pipe string by dropping a ball and applying hydraulic pressure to unlatch a latch mechanism. The drill pipe disconnect can also be actuated with a portion of the drill string off the bottom of the well bore. To disconnect the drill pipe disconnect mechanism with the drill string off bottom of the well bore, disconnection may only require that a higher pressure be applied to the interior of the drill pipe string above the dropped ball. It is a feature of this embodiment that an apparatus and method are provided for reconnecting the upper and the lower drill pipe sections after they have been disconnected. In this embodiment the upper and lower drill pipe sections may be re-engaged and then re-latched by dropping a ball and applying hydraulic pressure to securely re-latch the upper and lower drill pipe sections. It is also a feature of this embodiment that the re-latched drill pipe sections may subsequently be unlatched again, thereby facilitating repeated disconnects and reconnects as desired. The drill pipe reconnect and disconnect apparatus and methods are simple and reliable to operate and may save time and costs in disconnecting a drill pipe string at a pre-determined location. It is yet another feature of this embodiment that the drill pipe disconnect may provide an apparatus and method for rotating the drill string. Non-rotational engagement members are provided which may provide rotational strength within the disconnect apparatus which is substantially equivalent to the strength of the drill pipe. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified pictorial representation of a drilling rig, a riser assembly, a riser disconnect, a riser valve, a string of drill pipe, and a drill pipe disconnect in a drilling installation. FIG. 1A is a pictorial illustration of a riser male disconnect member disconnected from a female riser disconnect member, with an upper portion of drill pipe disconnected from a lower portion of drill pipe. FIG. 2 is a cross-sectional view of an upper portion of a riser disconnect assembly illustrated in cross-section. FIG. 2A is a side view of a riser disconnect lockout as shown in FIG. 2 , in a locked orientation. FIG. 3 is a cross-sectional view of lower portion of the riser disconnect assembly illustrated in FIG. 2 . FIG. 3A is an enlarged view of a collet mechanism illustrating a collet mechanism in a latched position. FIG. 4 is an enlarged half-section illustration of the riser disconnect collet mechanism generally illustrated in FIG. 3 . FIG. 5 is a cross-sectional view of a riser disconnect lockout wherein the left half of FIG. 5 illustrates the lockout mechanism in the locked orientation and the right half of FIG. 5 illustrates the lockout mechanism in the unlocked orientation. FIG. 5A is a side view of the riser disconnect lockout shown in FIG. 2 , in cross-section through the lockout pin illustrating retainers, grooves and stop dimples. FIG. 6 is a cross-sectional top view of a riser valve assembly, illustrating a ball pivot and the ball linkage adapter. FIG. 6A is a side view of a ball type sealing member shown in FIG. 6 , illustrating an engagement groove and engagement pin arrangement. FIG. 7 is a cross-sectional view of a subsea riser valve assembly, with a valve ball in the opened position. FIG. 8 is a cross-sectional top view of a subsea riser valve assembly illustrating a riser valve lockout device and a valve mandrel guide. FIG. 9 is an enlarged half-sectional view of a subsea riser valve with a valve ball in a closed position. FIG. 10 is a cross-sectional view of a drill pipe disconnect in the collet latched position initially installed, including an unlatching ball. FIG. 11 is a cross-sectional view of the drill pipe disconnect illustrated in FIG. 10 , with the latch sleeve moved downward to the collet unlatch position. FIG. 12 illustrates a lower end of a second assembly, a male reconnect member separated from the upper end of a female disconnect member, with the female disconnect member illustrating non-rotational engagement grooves. FIG. 13 is a cross-sectional view of a drill pipe disconnect with the second assembly, a male reconnect member engaged with the female disconnect member, in the collet unlatch position with a latching ball seated. FIG. 14 is an enlarged illustration of the disconnect shown in FIG. 13 , with the latch sleeve displaced downward in the collet latch position. FIG. 15 is an enlarged illustration of a portion of the disconnect shown in FIG. 13 , with the latch ball and latch seat ejected into the latch sleeve extension. FIG. 16 is a cross-sectional illustration of a drill pipe disconnect with a re-unlatching ball seated and the latch sleeve moved downward to the collet re-unlatch position. FIG. 17 is a cross-sectional view of a drill pipe disconnect collet mechanism illustrating collet dogs engaged with a female disconnect member and illustrating the fingers connecting the latch mandrel with the collet engagement ring. FIG. 18 . is a cross-sectional view of a riser disconnect embodiment including a non-rotational key engagement head which is engaged with a non-rotational key. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a generalized, suitable application for a subsea riser disconnect, a subsea riser valve and a drill pipe disconnect according to the present invention. In one embodiment, this invention includes three principle assemblies, namely: 1) a subsea riser disconnect assembly 10 , 2) a subsea riser valve assembly 20 , and 3) a subsea drill pipe disconnect assembly 30 . Each of these three principle assemblies may be provided in a drilling installation, separate and apart from or in combination with any or both of the other principle assemblies, or primary components. As disclosed subsequently, safety mechanisms may be included within each principle assembly to prevent inadvertent operation of that assembly. Each of these three primary components 10 , 20 , 30 may be employed individually or in conjunction with one or both of the other primary components. And each of these three components generally include a through bore extending through the component along a central axis 15 . The central axis 15 may substantially be common to each and all components. (It is understood and assumed throughout this disclosure, that all seals may be both hydraulic seals and pneumatic seals, notwithstanding the fact that a particular seal may be simply designated as a hydraulic seal or otherwise. It is also understood and assumed that all connections, secured components, attachments or otherwise joining of two or more components may effect a seal, unless designated otherwise. It is further understood and assumed that the terms drilling rig, rig, work over rig, and drill ship, semi-submersible and related terms may be used interchangeably and not in limitation.) One or more portions of a preferred embodiment of a sub-sea riser disconnect assembly 10 are illustrated in FIGS. 1 , 1 A, 2 and 3 , for sealingly connecting a lower riser 28 extending downward from above the mud line ML through a seabed SB and into a subsea well bore WB with an upper riser 35 extending downward from a drilling rig DR to the lower subsea riser 28 . The drilling rig DR may include floating types of drilling rigs DR such as a drill ship and a semi-submersible rig. The position of the drilling rig DR is not fixed with respect to the location of the wellbore WB. The lower subsea riser 28 may be secured within the wellbore WB, e.g., by a cementing operation, such that the riser disconnect assembly 10 may be selectively activated to disengage and/or reengage a lower end 37 of the upper riser 35 from an upper end 19 of the lower riser 28 . The subsea riser disconnect assembly 10 , the subsea valve assembly 20 , the drill pipe 36 , the drill pipe disconnect 30 and the wellbore WB may each include a through bore and a central axis 15 . Both the through bore and the central axis 15 may be substantially aligned along a common central axis 15 . The riser disconnect assembly 10 includes a male disconnect member 12 , which may be secured to the lower end 37 of the upper riser 35 , and has a central axis aligned along the axis 15 . The riser disconnect assembly 10 also includes a female disconnect member 18 for axially receiving the male disconnect member 12 therein. The female disconnect member 18 may be secured to upper end 19 of the lower riser 28 . The riser disconnect assembly 10 may provide a full bore opening, such that the minimum ID of the through bore of the riser disconnect assembly 10 is equal to or greater than the ID of at least one of the upper 35 and lower 28 riser sections. Those skilled in the art will appreciate that a riser may generally be comprised of tubular components having a common through bore for providing a conduit that connects a drilling rig DR with a downhole DH portion of a well bore WB that typically extends below the lower end of the riser, where a portion of the lower end of the riser is secured within the seabed, below the mud line ML. Riser Disconnect Male Member As illustrated in FIGS. 1 , 2 and 3 , a seal assembly 14 may provide a pneumatic seal in the connection between the outer surface of the male disconnect member 12 and a mating inner surface of the female disconnect member 18 . The male component of the seal assembly 14 includes an upper seal mandrel 42 , which may be connected to a lower end 19 of the upper riser 35 by a riser connector collar 41 . A lower end of the upper seal mandrel 42 may be connected to an upper end of a lower seal mandrel 56 . The lower end of the lower seal mandrel 56 in turn may be connected to a seal retainer 61 , which may be connected to latch mandrel 62 . The upper end of the latch mandrel 62 may be connected to the lower end of the seal retainer 61 , while the lower end of the latch mandrel 62 may generally include the lower end of the male disconnect member 12 . A commonly known latch J-slot groove 63 , as shown in FIG. 3 , may be included in the outer surface of the latch mandrel 62 , and may circumferentially surround the latch mandrel 62 , in either the pattern shown or another desired pattern. One or more seal elements 54 , also commonly known as packing elements, may be positioned axially along the outer surface of the lower seal mandrel 56 , between the upper seal mandrel 42 and the seal retainer 61 . The seal elements 54 may circumferentially encompass the outer surface of the lower seal mandrel 56 and may include an alternating arrangement of a variety of seal materials in alternative embodiments. The seal elements 54 need not be axially continuous along the lower seal mandrel 56 , and may be positioned in sets, at axial intervals along the male component and female component. The female component of the seal assembly 14 may include a seal bore receptacle 58 for engaging the seal elements 54 . The female disconnect member 18 is discussed in detail below. A riser interconnection device 40 may be included for releasably securing the male disconnect member 12 with the female disconnect member 18 . The riser interconnection device 40 may be actuatable in response to axial reciprocating movement of the upper riser 35 relative to the lower riser 28 from a connect position to a release position or from a release position to a connect position. This reciprocating movement may be effected by movement of the upper riser 35 at the drilling rig DR. In the release position, the male disconnect member 12 and the female disconnect member 18 may be uncoupled, thereby permitting mechanical separation of the upper riser 35 from the lower riser 28 , as discussed below. Referring to FIGS. 1 , 3 and 4 , the riser interconnection device 40 may include a collet mechanism 60 for releasably interconnecting the male disconnect member 12 with the female disconnect member 18 . Components of the collet mechanism 60 included in the male disconnect member 12 may include a collet latch sleeve 72 , a latch pin 74 and the collet locking sleeve 80 . The collet latch sleeve 72 may include a plurality of collet arms 76 , and each collet arm 76 may include a collet dog 78 for engaging a collet groove 82 . The collet groove 82 may be provided in the inner surface of a latch housing sleeve 84 of the female disconnect member 18 . The collet latch sleeve 72 , a plurality of collet arms 76 and corresponding plurality of latch dogs 78 may be circumferentially spaced about the external surface of the latch mandrel 62 for selectively interconnecting the plurality of collet dogs 78 with the collet groove 82 . The collet latch sleeve 72 , the plurality of collet arms 76 and the latch dogs 78 may be axially and rotationally moveable about the common central axis 15 , with respect to the latch mandrel 62 . One or more latch pins 74 may be secured in the collet latch sleeve 72 . The latch pins 74 may protrude radially inward from the inner surface of the collet latch sleeve 72 toward the central axis 15 for a distance sufficient for the latch pins 74 to engage the latch J-slot groove 63 , in the outer surface of the latch mandrel 62 . The intrusion of latch pins 74 into the J-slot groove 63 may not exceed the depth of the latch J-slot groove 63 . The plurality of collet arms 76 and collet dogs 78 are preferably made integrally part of the collet latch sleeve 72 . The plurality of collet arms 76 and collet dogs 78 extend downward from the collet latch sleeve 72 . The collet locking sleeve 80 may be immovably secured to the lower end of the latch mandrel 62 , below the collet latch sleeve 72 . A portion of the collet locking sleeve 80 may extend axially upward along the outer surface of the latch mandrel 62 for a sufficient distance such that, with the riser disconnect assembly 10 in the latched position, a tapered portion 81 of the collet locking sleeve 80 may be circumferentially positioned between an inner surface of the collet dogs 78 and an outer surface of the latch mandrel 62 . The tapered portion 81 of the collet locking sleeve 80 , which is between the inner surface of the collet dogs 78 and the outer surface of the latch mandrel 62 , may also be referred to as the collet engaging ring 81 . An outer surface of the collet engaging ring 81 includes the tapered surface which may taper upward to a circumferential upper edge. A load bearing shoulder at bottom of the collet dog 78 may be supported on load bearing shoulder at lower end of collet engaging ring 81 of collet locking sleeve 80 when the riser disconnect assembly 10 is in the latched position. A load bearing shoulder at top of the collet dog 78 may be supported on load bearing shoulder at upper end of a collet engagement groove 82 when riser disconnect assembly 10 is in the latched position. Riser Disconnect Female Member Referring to FIGS. 1 , 2 , 3 and 4 , the lower riser 28 extends upward from the mud line ML, generally toward the drilling rig DR. The lower end of the lower riser 28 may be connected to a well casing 32 which extends through a seabed and into a subsea wellbore WB. The female disconnect member 18 may include the latch housing sleeve 84 , a seal bore receptacle 58 , and an entry guide 34 . The latch housing sleeve 84 may also include the female portion of the collet mechanism 60 , e.g., the collet groove 82 for coupling with the companion male components of the collet mechanism 60 . A casing end of the latch housing sleeve 84 may be attached to the upper end of a well casing 32 or other component. A latch end of the latch housing sleeve 84 may include a collet groove 82 circumferentially within the inner surface of the latch housing sleeve 84 for releasably receiving and securing the collet dogs 78 of the male disconnect member 12 . The latch end of the latch housing sleeve 84 may be attached to the lower end of the seal bore receptacle 58 . An entry guide 34 may be secured to an upper end of the seal bore receptacle 58 , and may assist in aligning the male disconnect member 12 with the female disconnect member 18 during reconnection of the male disconnect member 12 and female disconnect member 18 . An entry guide retainer 52 may be used to secure the entry guide 34 to the seal bore receptacle 58 . The entry guide 34 may extend upward toward the water surface from the point of attachment to the female disconnect member 18 , with a frustoconically expanding circumference, thereby forming a generally cone shaped receptacle defined by surface 38 . Riser Disconnect Lockout Mechanism In addition to the latch mechanism and seal components, the riser disconnect assembly 10 may include a riser disconnect lockout 50 to prevent inadvertent or unintentional disengagement of the male disconnect member 12 from the female disconnect member 18 . The riser disconnect lockout 50 may typically be used in the locked configuration only during the initial connection, installation and cementing of the upper and lower riser assembly, when compressive forces may be experienced due to running, installing and cementing the casing 32 and/or the riser disconnect assembly 10 . The riser disconnect lockout 50 may otherwise normally remain in the unlocked position since the applied axial tensile forces in the upper riser 35 prevent disconnection of the male disconnect member and the female disconnect member. Referring to FIGS. 2 , 2 A, the riser disconnect lockout 50 may preferably be comprised of a shouldered pin and groove assembly. The riser disconnect lockout 50 preferably may be provided on the male disconnect member 12 , axially between the riser connector collar 41 and the lower seal mandrel 56 . Referring to FIGS. 1 , 2 , 2 A, 3 , 3 A, 4 , 5 , 5 A one or more lockout grooves 43 may be circumferentially provided on the outer surface of the upper seal mandrel 42 , each lockout groove to accommodate a lockout pin 46 . The one or more grooves 43 may each have a long axis which is aligned axially up and down along the upper riser 35 , substantially parallel with the central axis 15 . Each groove 43 includes a circular portion, at the lower end of the groove 43 , the circular portion having a diameter that is larger than the width of the groove 43 , as shown in FIGS. 2A and 5 . A riser disconnect lockout housing 48 may be circumferentially positioned on the external surface of the upper seal mandrel 42 , the riser disconnect lockout housing 48 being axially moveable along the central axis 15 , on the outer surface of the upper seal mandrel 42 . A riser disconnect lockout pin 46 may be provided for each lockout groove 43 . Referring to FIGS. 2A , 5 , and 5 A, the riser disconnect lockout pin 46 may include a round shaped upset providing lockout upset shoulders 45 and having two opposing flat sides where opposing portions of the round shaped upset are removed to provide the flat sides, on an inner end of the riser disconnect lockout pin 46 , the rounded portion provided along a major axis between the rounded ends and having a length that is larger than the diameter of the pin 46 , and a minor axis between the two flat sides which is substantially equal to the diameter of the pin 46 . Each lockout pin 46 may extend from inside of the riser disconnect lockout housing 48 , through a pin port 51 and may be furnished with a square socket for engagement with an ROV operating wrench (not shown). The round shaped portion of the riser disconnect lockout pin 46 remains inside of the riser disconnect lockout housing 48 in the respective lockout groove 43 . As illustrated in FIGS. 5 , 5 A, spring loaded and/or threaded or otherwise secured retainer pins 49 may be positioned within the riser disconnect lockout housing 48 to engage a retainer groove 53 in each lockout pin 46 to provide resistance to the pin 46 . Such configuration may thereby prevent inadvertent rotation of the pin 46 . In addition, the retainer groove 53 may only be provided circumferentially around a portion of the outer surface of the lockout pin 46 , such as ninety degrees, in order to provide rotational stop positions to ensure proper rotational orientation of the lockout pin 46 . Stop dimples 88 , as shown in FIG. 5A , may be provided on a portion of the lockout pin 46 to ensure proper respective locked and unlocked lockout pin 46 orientation. A lockout sleeve 44 may be concentrically disposed around a portion of the upper seal mandrel 42 . An upper end of the lockout sleeve 44 may engage the riser disconnect lockout housing 48 , and a lower end of the lockout sleeve 44 may engage the upper end of the seal bore receptacle 58 . The lockout sleeve 44 is axially moveable with respect to the upper seal mandrel 42 when lockout 50 is in the unlocked position. An alternative embodiment for a riser disconnect may include an apparatus to facilitate rotating an upper riser, a riser disconnect and a lower riser, substantially in unison to drill the lower riser into position in the sea bed. A bit 39 or under reamer bit may be positioned near the lower end of the lower riser 28 . Referring to FIG. 18 , a tubular, generally female, non-rotational key engagement head 340 may be secured to a female riser disconnect member to receive and engage a non-rotational key member 346 . The non-rotational key member 346 may be secured to an outer surface of a mandrel, such as a lockout sleeve 344 , which may be concentrically disposed around an upper seal mandrel 342 . The female non-rotational key engagement head 340 may include a tapered upper surface, which may be referred to as an upper key guide surface 345 , to guide insertion of the male member into non-rotational engagement with the female disconnect member. An extension mandrel 359 may support the female non-rotational key engagement head 340 and may support an entry guide 334 . An upper end of a seal bore receptacle 358 may connect with the lower end of the extension mandrel 359 . An extension mandrel adapter ring 360 may connect the seal bore receptacle 358 and the extension mandrel 359 . Such embodiment may facilitate rotating a lower riser with an upper riser which may be connected by a riser disconnect 10 . The non-rotational key engagement head 340 and non-rotational key member 346 components, or variations thereof such components, may be employed for purposes other than drilling in the lower riser 28 , such as rotating the lower riser in preparation for and/or during cementing operations, or to rotationally manipulate the lower riser 28 and/or upper riser 35 . Riser Disconnect, General Operation Referring to FIGS. 1 , 2 , 2 A, 3 , 3 A, 4 , 5 and 5 A, the riser disconnect assembly 10 , is generally operable by axial motion of the attached upper riser 35 relative to the lower riser 28 , using the drilling rig DR to effect axial motion or reciprocation. The male disconnect member 12 is latched into engagement with the female disconnect member prior to riser installation. When the riser disconnect assembly 10 is installed on a well as part of a riser assembly and in the connected and latched position, the upper riser 35 and lower riser 28 are normally under a tensile load, typically around one-hundred thousand pounds of force, between the drilling rig DR and the well casing 32 that extends into the wellbore WB and is cemented therein. The tapered portion or collet engaging ring 81 is circumferentially spaced between the inside of the plurality of collet dogs 78 and the outer surface of the latch mandrel 62 , causing the collet dogs to be engaged in the collet groove 82 . The tensile load on the male disconnect member 12 is carried through the collet locking sleeve 80 into the collet dogs 78 as a compressive load, through engagement of the collet locking sleeve 80 with the collet dogs 78 . The compressive load in the collet dogs 78 is transferred to the female disconnect member 18 through the engagement of the collet dogs 78 with the collet groove 82 , the collet groove 82 being a component of the female disconnect member 18 . In such riser tensile load configuration, the latch pin 74 is in a latched position 66 within the latch J-slot groove 63 . A load bearing shoulder at bottom of the collet dog 78 may be supported on load bearing shoulder at lower end of collet engaging ring 81 of collet locking sleeve 80 when the riser disconnect assembly 10 is in the latched position. A load bearing shoulder at top of the collet dog 78 may be supported on load bearing shoulder at upper end of a collet engagement groove 82 when riser disconnect assembly 10 is in the latched position. The load bearing lockout shoulders 45 of each riser disconnect lockout pin 46 are preferably normally positioned within the circular, lower portion of the respective lockout groove 43 and in a rotational orientation such that a long axis between the rounded end portions 47 of the lockout pin 46 may be axially aligned parallel to a long axis of the lockout groove 43 . In such orientation, the male disconnect member 12 may be unlatched from the female disconnect member 18 . Tensile load in the upper riser 35 may not act directly upon the riser disconnect lockout pin 46 . When in the locked orientation, the lockout pin 46 may prevent any compressive forces in the riser from inadvertently unlocking the riser disconnect assembly 10 , in that the load bearing shoulders 45 are not aligned to move along the lockout grooves 43 , as is otherwise required to disconnect the riser disconnect assembly 10 . The locked orientation may normally be used only in initial installation of the casing 32 , riser disconnect assembly 10 . Otherwise the lockout pin 46 will typically remain in the unlocked orientation. When the riser disconnect lockout 50 is in the locked position, as illustrated in the left half of FIG. 5 , compressive forces in the upper riser 35 prohibit an unlocking axial movement of the upper riser 35 relative to the lower riser 18 . Compressive forces tending to axially move the upper riser 35 relative to the lower riser 28 , such as may be experienced during riser installation, will transfer from the upper seal mandrel 42 to the load bearing lockout shoulders 45 of the lockout pin 46 , and from the lockout pin 46 to the riser disconnect lockout housing 48 . When applying compressive forces substantially at the riser disconnect assembly 10 , the riser disconnect lockout housing 48 will compressingly engage an upper portion of the lockout sleeve 44 , which in turn will compressingly engage an upper portion of the seal bore receptacle 54 . The seal bore receptacle 54 is an immovable component of the lower riser 28 . If the lockout pin is in the unlocked orientation, axial movement of the upper riser 35 relative to the lower riser 28 will result, thereby permitting disconnecting the riser disconnect assembly 10 . If the lockout pin 46 is in the locked orientation, substantially no axial movement of the upper riser 35 relative to the lower riser 28 will result, thereby preventing inadvertent disconnecting of the riser disconnect assembly 10 . The lockout pin 46 is preferably in the locked orientation during running and installation of the casing 32 , the lower riser 28 and upper riser 35 . After cementing operations are complete and tension is applied to the riser disconnect assembly 10 , a remotely operated vehicle (ROV), diver or other means may be employed to orient the disconnect lockout pin 46 to the unlocked orientation. Well operations may normally be carried on with the riser disconnect lockout 50 in the unlocked orientation. Riser Disconnect, Unlatching and Disconnecting Operation In the embodiment illustrated in FIGS. 1 , 2 , 2 A, 3 , 3 A, 4 , 5 and 5 A, to unlatch and disconnect the upper riser 35 from the lower riser 28 , the tensile load in the riser assembly may be relaxed and converted to a compressive load at the riser interconnection device 40 . If the lockout pin 46 is oriented in the locked position the riser disconnect lockout 50 must be unlocked, such as by ROV or diver, before the riser disconnect operation may be performed. The load bearing shoulders 45 of each riser disconnect lockout pin 46 , which are positioned within the circular, lower portion of the respective lockout groove 43 , may be rotated 90 degrees to a rotational orientation where the long axis portion of the lockout pin 46 providing the load bearing shoulders 47 , is aligned parallel to the long axis of each respective lockout groove 43 . When the riser disconnect lockout pin 46 is oriented in the unlocked position, axial downward displacement of the upper seal mandrel 42 relative to the lockout sleeve 44 is permitted, such that each lockout groove 43 in the upper seal mandrel 42 may axially move along the respective lockout pin 46 during the axial disconnect movement of the upper riser 35 . As the upper riser 35 is axially moved downward, the male disconnect member 12 moves downward within the female disconnect member 18 . Such displacement results in relative movement of the latch J-slot groove downward along the latch pins 74 . As downward movement continues, the latch pins 74 move from the latched position 66 in the latch J-slot groove 63 to the collet disengage position 64 , and the collet latch sleeve 72 , the latch pin 74 , the plurality of collet arms 76 and the collet dogs 78 move axially and rotationally to the collet disengage position 64 . As the latch mandrel 62 and connected collet locking sleeve 80 move downward, the tapered portion or collet engaging ring 81 of the collet locking sleeve 80 is moved downward and out from between the collet dogs 78 and latch mandrel 62 . The collet dogs 78 may thereby move radially inward toward the latch mandrel 62 and out of engagement with the collet groove 82 . At that point, the male disconnect member 12 is unlatched from the female disconnect member 18 , but is not disconnected. To disconnect the male disconnect member 12 from the female disconnect member 18 , an axial tensile force is applied by the drilling rig DR or other means, to the upper riser 35 . As the upper riser 35 moves upward relative to the lower riser 28 , the J-slot groove 63 in the latch mandrel 62 moves upward relative to latch pins 74 , from the collet disengage position 64 to the latch disconnect position 68 . Because the latch disconnect position 68 is relatively higher than the latch connect position 66 , the collet latch sleeve 72 and collet dogs 78 are prohibited from moving downward along the outer surface of the latch mandrel 62 sufficiently to permit the collet dogs 78 to engage the collet locking sleeve 80 . Thereby, during disconnection of the upper riser 35 from the lower riser, the collet dogs remain disengaged in the annulus between the outer surface of the latch mandrel 62 and the inner surface of the seal bore receptacle 58 . The components of the male disconnect member 12 , including the riser disconnect lockout 50 , the upper and lower seal mandrels 42 , 56 , the seal elements 54 , the riser interconnection device 40 and the collet mechanism 60 may be extracted from the seal bore receptacle 58 . The upper riser may be suspended from or removed to the drilling rig DR, leaving the lower riser in place on the well casing 32 . Riser Disconnect, Re-Connecting and Latching Operation In the embodiment illustrated in FIGS. 1 , 2 , 2 A, 3 , 3 A, 4 , 5 and 5 A, to reconnect and latch the upper riser 35 to the lower riser 28 , the upper riser 35 may be lowered from the drilling rig DR toward the lower riser 28 . The male disconnect member 12 should be guided into and through the entry guide 34 , to compressively set in the female disconnect member 18 . As the unlocked male disconnect member 12 is axially moved downward through the female disconnect member 18 , such displacement results in relative movement of the latch J-slot groove downward from the unlatched or disconnect position 68 , along the latch pins 74 . As downward movement continues, the latch pins 74 move from the unlatched or disconnect position 68 in the latch J-slot groove 63 to a top position 67 , resulting in the collet latch sleeve 72 , the latch pins 74 , the plurality of collet arms 76 and the collet dogs 78 moving axially and rotationally on the latch mandrel. As the latch mandrel 62 and connected collet locking sleeve 80 move downward, the collet dogs 78 will engage the collet groove 82 . The male disconnect member 12 may bottom out on an upset surface 87 in the latch housing sleeve 84 . To re-latch the riser interconnection device 40 , tension may be applied to the upper riser 35 from the drilling rig DR, such that the upper riser 35 may begin to move upward relative to the lower riser 28 . As the latch mandrel 62 begins moving upward, the latch pins 74 remain alternatively axially immobile, due to the collet dogs 78 engaged within the collet groove 82 . The latch J-slot groove 63 will move upward relative to the latch pins 74 , repositioning the latch pins 74 from the top position 67 to one of the latch engaged positions 66 . As the latch pins 74 approach the latch engaged position 66 , the collet locking ring 81 may circumferentially slide between the inside of the collet dogs 78 and the outside of the latch mandrel 62 . The collet dogs 78 may thereby move radially outward toward the latch housing sleeve 84 , forcing the collet dogs 78 to fully engage the locking groove 82 . At that point, the male disconnect member 12 is securely reconnected and latched into the female disconnect member 18 . Tension is preferably sustained within the upper riser 35 from the drilling rig DR in order to maintain the riser interconnection properly in the latched position. The riser disconnect lockout 50 typically remains in the unlocked orientation during drilling operations. In the event it is alternatively desired to lock the riser disconnect lock 50 , a remotely operated actuator, diver or other means are used to reorient the riser disconnect lockout pin 46 to a locked position. From the typically unlocked position, the load bearing shoulders 45 of each riser disconnect lockout pin 46 , which, (with the riser in tension) are normally positioned within the circular, lower portion of the respective lockout groove 43 , may be preferably rotated 90 degrees to a rotational orientation where the long axis of the round portion 47 of the lockout pin 46 which includes the load bearing shoulders 45 , is aligned perpendicular to the long axis of each respective lockout groove 43 . Such locked orientation of the lockout pins 46 prohibits axial downward displacement of the upper seal mandrel 42 relative to the lockout sleeve 44 , thereby locking the riser disconnect in a latched position. Alternatively, the riser disconnect assembly 10 and lower riser 28 may be drilled into position in the sea bed while the well bore WB which is to accommodate insertion of the lower riser therein is being drilled. This may be accomplished by a number of means known within the industry. The lower riser 28 , upper riser 35 and the riser disconnect assembly 10 may be rotated substantially in unison, from the drilling rig DR. Additionally, rotating the lower riser 28 may be desirable in the event a ledge is encountered while installing the lower riser, wherein it may be desired to rotate the lower riser in order to assist insertion of the lower riser in a hole or well bore. An alternative embodiment of a riser disconnect assembly 10 for accomplishing such objectives is illustrated in FIG. 18 , and disclosed above. Alternatively, depending upon water depth, the riser disconnect 10 , the lower riser 28 and/or the upper riser 35 , or a portion thereof as determined by water depth, may be positioned on the seabed. A string of drill pipe 36 , a drill bit 39 and/or an under reamer bit may be deployed through the positioned riser assembly and the drill string 36 may rotate the riser string along with the bit 39 while drilling the lower riser 28 into the seabed. Those skilled in the art of well drilling operations will appreciate that there are a number of other means for drilling in the lower riser 28 . In another alternative embodiment of the riser disconnect assembly 10 , the seal elements 54 may be positioned within one or more grooves in the inner wall of the seal bore receptacle 58 , as opposed to being carried upon the generally male component, the lower seal mandrel 56 . In such alternative configuration, the lower seal mandrel may then provide a generally smooth outer surface for insertion and sealing with the seal elements 54 . Another alternative embodiment may include a riser flex joint (not shown) connected to the male or female component of the riser disconnect assembly 10 . The flex joint may be connected in the riser string between one of the riser connector collar 41 and one of the upper riser 35 and the lower riser 28 , or between the latch housing sleeve 84 and the other of the upper riser 35 and lower riser 28 , depending upon orientation of the riser disconnect assembly 10 . As an alternative to use with floating drilling rigs DR, such as semi-submersibles and drill ships, the subsea riser disconnect may be used with other types of drilling rigs, such as submersibles, drilling barges or jack-up type drilling rigs. In the event the riser disconnect point is sufficiently far above the mud line, when the riser disconnect is disconnected, buoyancy cans (not shown) may be attached to the lower riser below the riser disconnect and above the mud line ML. Other alternative embodiments may provide for employing an embodiment of the riser disconnect assembly on production wells, development wells and wells other than exploratory or test wells. Riser Valve Assembly FIGS. 1 , 6 , 6 A, 7 , 8 and 9 illustrate a suitable embodiment for a subsea riser valve assembly 20 according to the present embodiment. The subsea riser valve assembly 20 may be used as a stand alone device in a subsea riser installation or may be used in conjunction with the subsea riser disconnect assembly 10 . In an installation where the subsea riser valve assembly 20 is employed in conjunction with the subsea riser disconnect assembly 10 , the two components may be configured as a common component assembly, as generally illustrated in FIG. 1 , or preferably as two separate component assemblies, as generally illustrated in FIGS. 2 , 3 , 7 and 9 . The riser valve assembly 20 may provide a full bore opening when the valve seal element is in the opened position, such that the minimum ID of the through bore of the riser valve assembly 20 is equal to or greater than the ID of one or both of the upper 35 and lower 28 riser. The riser valve assembly 20 may provide a method for isolating the lower riser 28 prior to disconnecting and removing the upper riser 35 from the lower riser 28 , and thereby closing in the well bore WB below the riser valve assembly 20 . Those skilled in the are will appreciate that a riser valve 20 is generally a part of a riser system that includes an upper 35 and lower riser 28 , and that the riser valve may thereby include components generally having tubular properties, such as a through bore. Additionally, it may be appreciated that the riser valve 20 may include components which may be similar to components found in valves. In an application wherein the riser valve assembly 20 is a distinctly separate component from the riser disconnect assembly 10 , the subsea riser valve assembly 20 may be preferably installed in an upper portion of the lower riser 28 . The lower riser 28 may be comprised of well casing 28 , which extends downward through a seabed and into the subsea wellbore WB where the lower riser is secured by cementing the lower riser 28 within the wellbore WB. The lower riser 28 may include or may be partially comprised of threaded well casing pipe 32 . The subsea riser valve assembly 20 may include components for selectively closing off the through bore in the lower riser, thereby hydraulically isolating and enclosing the interior of the lower riser 28 and the wellbore WB below the lower riser 28 . FIG. 7 illustrates a cross-sectional view of a preferred embodiment for a subsea riser valve assembly 20 , with the riser valve assembly 20 in the opened position. FIG. 9 illustrates an enlarged half-section view of the riser valve, with the riser valve assembly 20 in the closed position. A preferred embodiment includes valve housing components 110 , 112 , 114 , and 134 , a valve sealing member 120 , a valve actuating mandrel 118 , and components 128 and 130 which connect the valve actuating mandrel 118 and the valve sealing member 120 . The subsea riser valve assembly 20 may be actuated between the valve opened position and the valve closed position by axial movement of the upper riser 35 relative to the lower riser 28 , by the drilling rig DR or by other means. The riser valve assembly 20 preferably is designed to fail closed such that tension on the riser assembly and the subsea riser valve assembly 20 is required to maintain the subsea riser valve in an opened position. Thus, under normal operating conditions, the subsea riser valve requires tensile force between the upper and lower ends of the riser valve assembly 20 . Releasing the tension or compressing the riser string at the riser valve assembly 20 may preferably result in closure of the riser valve assembly 20 . Referring to FIGS. 1 , 6 , 6 A, 7 , 8 and 9 , a preferred orientation for the subsea riser valve provides for installing the subsea riser valve assembly 20 with the valve actuating mandrel 118 connected to the upper riser 35 and with a lower valve housing 110 connected to the casing 32 extending below the mud line ML, with the casing 32 comprising a portion of the lower riser 28 . In such orientation, a lower end of a lower valve housing 110 may be secured, such as by threaded connection, to an upper end of a well bore casing 32 . A lower end of a central valve housing 112 may be secured, such as by threaded connection, to an upper end of the lower valve housing 110 . An upper valve housing 114 may be secured to an upper end of the central valve housing 112 , while a lower end of a valve mandrel housing 116 may be secured to an upper end of the upper valve housing 114 . A lower end of the valve actuating mandrel 118 may telescopically penetrate the upper end of the valve mandrel housing 116 and into an upper end of the upper valve housing 114 . An upper end of the valve actuating mandrel 118 may be secured to the lower end of the upper riser 35 . The riser valve assembly 20 includes a valve sealing member 120 that may be actuated in response to movement of the valve actuating mandrel 118 . In a preferred embodiment, the valve sealing member 120 is a ball type sealing member, being rotatable about a ball axis 121 . Ball pivots 126 may extend along the ball axis 121 , from the generally spherically shaped valve sealing member 120 to maintain orientation during rotation of the sealing member 120 between a valve opened position and a valve closed position. The ball type sealing member 120 includes a through bore that provides a generally continuous through bore through the riser assembly and the riser valve assembly 20 , when the riser valve is in the valve opened position. The valve sealing member 120 is generally positioned between the upper 114 and lower 110 valve housings, and within the central valve housing 112 . The valve sealing member may move rotationally on the ball pivots 126 , which in turn may be mounted within one or more ball mounts for supporting the ball pivots 126 during valve manipulation. The upper portion of the lower valve housing 110 may include a lower valve seat 122 to provide a hydraulic seal between the lower valve housing 110 and the valve sealing member 120 . An upper valve seat 124 may be included to provide a hydraulic seal between the upper valve housing 114 and the valve sealing member 120 . One or more seat engagement springs 141 may be provided to enhance the hydraulic seal between the valve sealing member 120 and the lower seat 122 . Wafer type corrugated springs, or other types of seal enhancement mechanism may be employed to effect seal enhancement. The valve actuating member 118 may be connected with the valve sealing member 120 with a valve link pin 130 and a link pin adapter 128 . The valve actuating mandrel 118 may include an annular support ring 134 with a plurality of valve link sockets 137 , preferably two valve link sockets 137 , providing one on each side of the actuating member 118 . The each respective annular support ring 134 may move axially within one a respective mandrel guide groove 132 , within the inner surface of the valve mandrel housing 116 . The annular support rings 134 may be connected to an upper end of a valve link pin 130 . A retainer 136 may be provided on the upper end of each valve link pin 130 to secure the valve link pin 130 within the its respective valve link socket 137 . The valve link pin 130 may extend downward from the annular support ring 134 and penetrate the upper valve housing 114 through an upper valve housing passageway 117 , and extend below the upper valve housing 114 to connect with a link pin adapter 128 . The link pin adapter 128 may be moveably disposed within the central valve housing 112 to axially reciprocate along a link pin adapter passage 119 . The link pin adapter 128 may include a link pin adapter projection 131 to engage the valve seal member 120 in a seal member engagement groove 133 , as illustrated in FIG. 6A . To prevent rotation of the valve actuating mandrel 118 relative to the mandrel housing 116 , one or more mandrel guides 146 may be positioned within corresponding grooves provided in both the outer surface of the valve actuating mandrel 118 and the inside surface of the valve mandrel housing 116 , as illustrated in FIGS. 7 and 8 . The mandrel guides may be secured to the mandrel housing 116 with mandrel guide retainers 140 for each respective mandrel guide 146 . The valve actuation mandrel 118 may axially reciprocate along the one or more relatively immovable mandrel guides 146 . A preferred embodiment provides two mandrel guides 146 and two mandrel guide retainers 140 . In a preferred embodiment, the riser valve assembly 20 is designed to remain closed until sufficient tension may be applied to the riser valve assembly 20 to actuate the valve sealing member 120 to the opened position. During installation of the riser valve assembly 20 , the lack of sufficient tension may prevent the valve sealing member 120 from remaining in the valve opened position. To retain the riser valve in a valve opened position during riser installation, and at any time subsequent to installation, a riser valve lockout assembly 150 may be included. The riser valve lockout assembly 150 may be provided within the valve mandrel housing 116 to act upon the valve actuating mandrel 118 to prevent axial displacement of the valve actuating mandrel 118 relative to the mandrel housing 116 . The riser valve assembly 20 may be locked or may remain unlocked, when the valve sealing member 120 is in either the valve opened position or the valve closed position. Referring to FIGS. 1 , 7 , 8 and 9 , one or more valve lockout grooves 151 may be circumferentially provided on the outer surface of the mandrel housing 116 , each lockout groove 151 to accommodate a respective lockout device 153 . The combination of a lockout groove 151 plus a lockout device 153 may constitute a lockout assembly 150 . The one or more valve lockout grooves 151 may each have a long axis which is aligned axially up and down along the valve actuating mandrel 118 , substantially parallel with the central axis 15 . Each groove 151 includes a circular portion at the lower end of the groove 151 and at the upper end of the groove 151 , each circular portion having a diameter that is larger than the width of the groove 151 . The riser valve lockout device 153 is axially moveable along the central axis 15 , on the outer surface of the valve actuating mandrel 118 . The riser lockout device 153 may include a lockout pin 148 , a lockout pin adapter 154 and a lockout pin connector bolt 152 connecting the lockout pin 148 and the lockout pin adapter 154 . The riser lockout pin 148 may be substantially round shaped with a pair of opposing flat sides, such that the round shoulders may provide a pair of upset shoulders 147 on the riser valve lockout pin 148 . The round ends of the lockout pin 148 may be axially located along a major linear axis through the lockout pin, the long axis having a length that is longer than the length of a minor axis which extends between the flat sides of the lockout pin 148 . The length of the minor axis may be substantially equal to the diameter of the lockout pin adapter 154 . Each valve lockout device 153 may extend from inside of a lockout groove 151 , outward through a pin port 157 in the valve mandrel housing 116 . The rounded end portion 147 of the riser valve lockout device 153 may remain inside of the groove 151 on the outer surface of the riser valve actuating mandrel 118 . In an unlocked orientation, the lockout pin adapter 154 may slide in lockout groove 151 , along a grooved but non-recessed portion 138 of the valve mandrel housing 116 . As illustrated in FIG. 8 , and generally referring to the illustration depicted in FIG. 5A , spring loaded retainer pins 159 may be positioned within the riser valve mandrel housing 116 to engage a retainer groove 167 and/or stop dimple 88 on an outer surface of each lockout pin adapter 154 and may thereby prevent inadvertent rotation of the lockout device 153 and may assist the ROV, diver or other actuator in properly aligning the upset shoulders 147 on the lockout pin 148 with respect to the lockout groove 151 . The retainer groove 167 and/or stop dimple 88 may only be provided circumferentially around a portion of the outer surface of the lockout pin adapter 154 , such as substantially ninety degree portions of the lockout pin adapter 154 . The riser valve lockout assembly 150 functions similar to the riser disconnect lockout disclosed above. As lockout pin 148 is rotated, such as by ROV or diver, within one of the upper or lower circular portions of the lockout groove 151 to the valve locked orientation, the upset shoulders 147 are oriented so as not to be axially moveable through the narrow portion of the lockout groove 151 . The resulting inability of the lockout device 153 to move axially along the lockout groove 151 provides the capability to lock the valve 20 in either a valve opened or valve closed position, depending upon whether the lockout device 153 is engaged in the upper or lower circular portion, respectively, of the lockout groove 151 . This assembly may provide the ability to install the riser valve assembly 20 in either a valve opened or a valve closed position. In an alternative embodiment, a valve sealing member may be generally positioned within a valve housing which includes component variations from a valve housing discussed above that includes the upper 114 and lower 110 valve housings, and the central valve housing 112 . In an alternative embodiment, a central valve housing may be included as an integral portion of a lower valve housing or an upper valve housing. Riser Valve Operation The subsea riser valve assembly 20 is preferably an independent, stand-alone device which may be inter-connected with numerous other devices or related riser components, such as the riser disconnect, a riser flex joint, or other subsea equipment. The riser valve assembly 20 is preferably installed in tandem with the riser disconnect assembly 10 , such that the riser disconnect is positioned axially above the riser valve assembly 20 . Both assemblies, 10 , 20 , are generally inter-connnectably and operationally compatible, as both may be actuated through application and/or reduction of axial tensile force. FIG. 1 generally illustrates a preferred embodiment for a riser valve assembly 20 installation. A subsea riser valve assembly 20 as illustrated in FIGS. 1 , 6 , 7 , 8 and 9 , may be actuated through riser axial reciprocation at the drilling rig DR. The lower valve housing 110 of the riser valve assembly 20 may be connected to the upper end of a lower riser 28 . The lower riser 28 may be comprised of one or more joints of well casing pipe 32 of sufficient length that the lower riser 32 may be positioned within a well bore WB such that an upper portion of the lower riser 28 and the riser valve assembly 20 remain externally accessible above the mud line ML to an ROV, actuator or diver, e.g., to lock or unlock the valve lockout assembly 150 . The upper end of the valve actuating mandrel 118 may be directly or indirectly secured to the upper riser 35 , which extends substantially from the riser valve assembly 20 to the drilling rig DR. The riser valve assembly 20 is preferably actuated to mechanically fail closed and to remain in the valve closed position, in the absence of a tensile force applied to the riser valve assembly 20 to maintain the riser valve assembly 20 in the opened position. During installation, the riser valve assembly 20 may be positioned in the valve opened orientation and the lockout device 153 rotated to the locked position, within the lower circular portion of the lockout groove 151 , to allow fluid to fill the upper 35 and lower 28 risers and to facilitate circulation of fluids, slurrys and/or cement through the upper and lower riser. The lower riser 28 may be anchored within the well bore WB by placing cement in the annulus between the well bore WB and the outer surface of the well casing 32 . After the cement hardens, tension may be applied by the drilling rig DR, to the upper riser 35 , the riser disconnect assembly 10 , the riser valve assembly 20 and the portion of the lower riser 28 that is not cemented in the well bore WB. When tension is applied to the subsea riser valve assembly 20 , the valve lockout device may be rotated to the valve unlocked position. The riser lockout device 153 preferably remains rotationally oriented in the unlocked position during drilling and well work operations, such that the riser valve assembly 20 may be closed within a relatively short period of time by releasing tension in the upper riser 35 . Referring to FIGS. 6 , 6 A, 7 , 8 and 9 , during riser valve assembly 20 closing operations, as tension is released in the upper riser 35 the weight of the upper riser 35 may provide an axially downward force acting upon an upper portion of the valve actuation mandrel 118 . The downward compressive forces acting upon the valve actuation mandrel 118 may cause the valve actuation mandrel 118 to telescopically move downward within the valve mandrel housing 116 and the upper valve housing 114 . Downward movement of the actuation mandrel 118 may be limited by interference between the top of the valve lockout groove 158 and the valve lockout device 153 . The link pin adapter projection 131 on the link pin adapter 128 , which is secured to the lower end of the valve link pin 130 , is moveably engaged with the valve sealing member 120 . As the valve link pin 130 moves downward, the link pin adapter projection 131 may act generally tangentially upon the valve sealing member 120 to effect rotation of the valve sealing member 120 from an opened position to a closed position. The mere weight of components above the riser valve assembly 20 , in the absence of tension in the upper riser 35 , may provide a “fail closed” biasing effect to the sealing member 120 . In an alternative embodiment of a riser valve assembly 20 , a separate and/or additional biasing force may be provided, such as a spring, which may also contribute to closing the riser valve assembly 20 . The biasing effect in either the preferred or an alternative embodiment may serve to close the riser valve sealing member 120 on demand or in the event of loss of tensile force, and to maintain the riser valve assembly 20 in a closed position, such as when the upper riser 35 may be separated and removed from the riser valve assembly 20 . To open a preferred embodiment of the riser valve assembly 20 , tensile force may be applied to the valve actuation mandrel 118 . As the valve actuation mandrel 118 is telescopically extended from within the upper valve housing 114 and the valve mandrel housing 116 , the link pin 130 and link pin adapter 128 , which connect the valve actuation mandrel 118 and the valve sealing member 120 , engage the valve sealing member 120 to cause the valve sealing member 120 to rotate from the valve closed position to the valve opened position. A lower valve seat 122 may form a hydraulic seal between the moveable valve sealing member 120 and the lower valve housing 110 . An upper valve seat 124 may form a hydraulic seal between the moveable valve sealing member 120 and the upper valve housing 114 . On O-ring seal 115 may provide a hydraulic seal between the lower end of valve actuation mandrel 118 and the upper valve housing 114 . In an alternative embodiment of a riser valve assembly, the valve sealing member may be of a type other than a ball type sealing member, such as a gate type sealing member, a plug or cylinder type sealing member or a flapper type sealing member. These alternative type of sealing members may require variations and modifications on the linkage apparatuses required to effect valve manipulation between the valve opened position and the valve closed position, by axial motion or reciprocation of the valve actuation mandrel 118 . In other alternative embodiments, the riser valve assembly 20 may be inverted from the preferred embodiment, such that the valve actuation mandrel 118 is secured to the well casing 32 and a valve body, such as the lower valve housing 110 , is secured to the upper riser 35 . Axial reciprocation of the upper riser 35 would nevertheless effect movement of the valve body relative to the valve actuation mandrel 118 , thereby effecting manipulation of the valve sealing member 120 between the valve opened position and the valve closed position. An alternative embodiment for the subsea riser valve assembly 20 may integrate the subsea riser valve and subsea riser disconnect assembly 10 into a substantially single assembly which includes both components 10 , 20 . In such assembly, both the subsea riser disconnect assembly 10 and subsea riser valve assembly 20 may share common housing components. As an alternative to positioning a subsea riser valve assembly 20 substantially adjacent and below a subsea riser disconnect assembly 10 , the subsea riser valve may be installed at any point in a riser assembly, including the lower riser 28 and the upper riser 35 , where it may be desirable to provide a valve for closing off an interior portion of a riser through bore. Drill Pipe Disconnect FIGS. 1 , and 10 through 17 illustrate suitable embodiment for a drill pipe disconnect 30 according to the present invention. The drill pipe disconnect 30 may be used offshore and onshore, along a string of drill pipe 36 used in drilling a subterranean well. In an offshore installation, the drill pipe disconnect may be employed in a drilling installation which also employs a riser disconnect assembly 10 and a subsea riser valve assembly 20 . In general, the drill pipe disconnect 30 provides a means for selectively disconnecting an upper portion of a drill pipe string 36 from a lower portion of the drill pipe string 36 , while leaving the lower portion of the drill pipe string 36 , e.g., within the well bore WB being drilled. The drill pipe disconnect 30 also generally includes an interconnection means which provides for rotating the drill pipe string 36 and for axially transmitting tension and compression in the drill pipe string 36 , through the drill pipe disconnect 30 . The drill pipe disconnect 30 may be hydraulically or otherwise actuated between latched and unlatched positions. After disconnection of the drill pipe disconnect 30 , the drill pipe disconnect 30 may be reconnected, e.g., by hydraulic actuation of the latch mechanism. In a preferred embodiment, a drill pipe disconnect 30 may be employed in a subsea installation and in conjunction with a subsea riser disconnect assembly 10 and a subsea riser valve assembly 20 . The drill pipe disconnect 30 may be secured within the drill pipe string 36 such that when a drill bit 39 or lower end of the drill pipe string 36 is on or near the bottom of the well bore WB, the drill pipe disconnect 30 may be positioned below the subsea riser valve assembly 20 and the riser disconnect assembly 10 . In such configuration, the drill pipe string 36 may be disconnected at the drill pipe disconnect 30 , and the upper portion of the drill pipe string 36 may be pulled above the subsea riser valve assembly 20 in order that the subsea riser valve assembly 20 may be closed, thereby sealingly isolating the well bore WB and the lower portion of the drill pipe string 36 within the well bore WB. A preferred embodiment of the drill pipe disconnect 30 , as illustrated in FIGS. 10 through 17 , provides for male and female interconnection components. In addition, the preferred embodiment provides for a non-rotational engagement mechanism to facilitate rotational strength in the drill pipe disconnect 30 , and a collet mechanism for providing axial engagement and disengagement of the male and female interconnection components. The male interconnection component may generally be referred to as the male disconnect member 205 , while the female interconnection component may generally be referred to as the female disconnect member 215 . Each of the male disconnect member and female disconnect may include a through bore and a central axis 215 which may be a common to the disconnect members when the drill pipe disconnect 30 is connected. The male disconnect member 205 may be secured to the lower end of an upper portion of drill pipe 236 . An upper end of an upper latch sleeve housing 210 may be secured to the lower end of the upper portion of drill pipe 236 . The lower end of the upper latch sleeve housing 210 may be secured to the upper end of a male drill pipe disconnect housing 212 . A lower end of the male drill pipe disconnect housing 212 may be secured to the upper end of a latch mandrel 222 . The lower end of the latch mandrel 222 may include a latch mandrel collet engaging ring 237 . (Referring to FIGS. 10 and 17 , the latch mandrel collet engagement ring 237 is preferably an integral portion of the latch mandrel 222 , which is distinguished with a separate component number ( 237 ) and name to assist in clarifying this disclosure.) A latch sleeve 216 may be moveably positioned within the through bore of the male disconnect member 205 . The outer surface of the latch sleeve may be moveably engaged with the inner surfaces of each of the upper latch sleeve housing 210 , the male drill pipe disconnect housing 212 , the latch mandrel 222 and the latch mandrel collet engaging ring 237 . The lower end of the latch sleeve 222 may axially extend below the lower end of the latch mandrel collet engaging ring 237 , such that the lower end of the latch sleeve 216 defines the lower end of the male disconnect member 205 . A collet mechanism 230 may be included on the male disconnect member 205 for selectively securing and unsecuring the male disconnect member 205 with the female disconnect member 215 . The collet mechanism 230 includes a collet ring secured to and circumferentially encompassing a portion of the outer surface of the latch mandrel 222 . A plurality of collet fingers 231 may be spaced circumferentially around the latch mandrel 222 , with an upper end of each respective collet finger 231 secured to the collet ring 229 , and a lower end of each respective collet finger 231 secured to a respective collet dog 232 . The plurality of collet dogs 232 may be positioned near the lower end of the latch mandrel 222 , and extend inwardly through square windows 237 positioned in latch mandrel 222 to contact outer surface of latch sleeve 216 such that, in a latched position, the collet dogs 232 may engage the female disconnect member 215 in a collet engagement groove 239 . A shear pin retainer ring 218 may be provided radially between the outer surface of the latch sleeve 216 and the inner surface of the male drill pipe disconnect housing 212 , and axially below the upper latch sleeve housing 210 and axially above the latch mandrel 222 . The shear pin retainer ring 218 may house one or more shear pins 220 which engage both the shear pin retainer ring 218 and the latch sleeve 216 for prohibiting the latch sleeve 216 from axial movement until the shear pins 220 are selectively sheared. A collet unlatch groove 224 may circumferentially encompass the outer surface of the latch sleeve 216 , such that alignment of the collet unlatch groove 224 with the plurality of collet dogs 232 may provide for radially receiving the collet dogs 232 within the unlatch groove to provide for disconnection of the male disconnect member 205 and the female disconnect member 215 . An axial position of the latch sleeve 216 wherein the collet unlatch groove 224 on the latch sleeve 216 is aligned with the plurality of collet dogs 232 may generally be referred to as a collet unlatch position. When the collet unlatch groove 224 is not aligned with the collet dogs 232 , such that the collet dogs 232 are caused to engage the collet engagement groove 239 of the female disconnect member 215 by an the latch sleeve 216 , such axial position of the latch sleeve 216 may generally be referred to as a collet latch position. When the male disconnect member 205 is engaged with the female disconnect member 215 , a male frustoconical surface 244 substantially on the lower end of the latch mandrel collet engaging ring 237 engages a companion female frustoconical surface 234 in the female disconnect member 215 . Engagement of the frustoconical surfaces 234 , 244 provides compressive load bearing shoulders between the male disconnect member 205 and the female disconnect member 215 . Downward axial movement thereafter of the latch sleeve 216 relative to the latch mandrel 222 effects manipulation of the drill pipe disconnect 30 between the collet latch position and the collet unlatch position. During movement of the latch sleeve 216 , the latch sleeve may telescopically and sealingly penetrate a lower portion of the through bore of the female drill pipe disconnect housing 228 axially below the female frustoconical surface 234 . The inner surface 245 of the lower portion of the through bore of the female drill pipe disconnect housing 228 which receives the latch sleeve 216 , in combination with seal 246 may provide a moveable hydraulic seal between the female disconnect housing 228 and the latch sleeve 216 . An upper surface of the latch sleeve 216 may include an unlatching seat for sealing engagement with an unlatching ball 208 . Pressurized engagement of the unlatching ball 208 on the unlatching seat may permit shearing of the shear pins 220 and axial downward of movement of the latch sleeve 216 relative to the latch mandrel 222 . The outer surface of the latch sleeve 216 may include a circumferential first shear pin retainer ring groove 260 having a first shear pin retainer upper stop surface 264 . The first shear pin retainer ring groove 260 may circumferentially accommodate the shear pin retainer ring 218 . The shear pin retainer ring 218 includes an upper retainer ring stop surface 262 . After shearing the shear pins 220 , axial downward movement of the latch sleeve 216 relative to the latch mandrel 222 , from the collet latch position to the collet unlatch position, is halted by interference between the upper retainer ring stop surface 262 and first shear pin retainer ring groove upper stop surface 264 . Such interference position of the latch sleeve 216 relative to the latch mandrel 222 may properly align the collet unlatch groove 224 with the collet dogs 232 , in the unlatch position, to permit disconnecting the male disconnect member 205 and the female disconnect member 215 . The female disconnect member 215 may include a receptacle bore 241 for receiving the male disconnect member 205 . The collet engagement groove 239 may be positioned circumferentially in an inner wall of the receptacle bore 241 . A female non-rotational engagement member 227 , as illustrated in FIGS. 10 and 12 , may be included with the female disconnect member 215 for engaging a companion male non-rotational engagement member 226 , the male non-rotational engagement member 226 being a component secured to the male disconnect member 205 . The lower end of the female disconnect member 215 may be engaged with an upper end of the lower portion of drill pipe 240 . Seals 246 , 247 , packing or other sealing devices may be included to provide hydraulic seals between the male disconnect member 205 , male reconnect member 225 and female disconnect member 215 , and between the latch sleeve 216 , 266 and the upper latch sleeve housing 210 . It will be apparent to one skilled in the art that a wide variety of seals and component variations are conceivable and may be applied to apparatus and embodiments of this invention. Consequently, not all seals may be illustrated and/or discussed in this disclosure. Drill Pipe Disconnect Assembly Configured for Re-Connection and Re-Unlatching In a preferred embodiment for the drill pipe disconnect 30 , when the drill pipe disconnect 30 has been disconnected and the male disconnect member 205 recovered to the drilling rig DR, before reconnecting the male disconnect member 205 with the female disconnect member 215 , the male disconnect member 205 may be replaced with a male reconnect member 225 . FIGS. 13 , 14 , 15 and 16 illustrate a preferred embodiment for the redressed male reconnect member 225 . The redressed male reconnect member 225 generally includes similar components as the original male disconnect member 205 with the following modifications. The male drill pipe disconnect housing 212 may be replaced with a male drill pipe disconnect housing 261 which provides ports for insertion of one or more shear pins which may be sheared at two positions on each shear pin (discussed below) or with two separate sets of shear pins. The original latch sleeve 216 is replaced with a latch sleeve 266 that provides an additional collet unlatching groove, referred to as a collet re-unlatching groove 274 , circumferentially on the outer surface of the latch sleeve 266 and axially above the original collet unlatch groove 224 . The radially raised circumferential surface between the collet unlatch groove 224 and the collet re-unlatch groove 274 may be referred to as the collet latch surface 263 . The latch sleeve 266 includes an additional groove 275 substantially adjacent the first shear pin retainer groove 260 , the additional groove being referred to as the second shear pin retainer groove 275 . The second shear pin retainer groove 275 may be located on the outer surface of the latch sleeve 266 , axially between a bottom surface of the shear pin retainer ring 268 and a latch mandrel upper stop surface 270 , and may circumferentially encompass the outer surface of the latch sleeve 266 . The second shear pin retainer groove 275 may permit movement of the latch sleeve 266 between a collet latch position and a collet re-unlatch position. The shear pin retainer ring 268 may include a port for providing two separate sets of shear pins or a set of double position shear pins 269 . The double position shear pin 269 may extend from a series of aligned ports, from the male drill pipe disconnect housing 261 through the shear pin retainer ring 268 , and into an annular groove in the outer surface of the latch sleeve 266 . As illustrated in FIG. 13 , a latching seat 285 for sealingly seating a latching ball 286 thereon may be included near the lower end of the latching sleeve 266 , with the latching seat 285 secured to an inner surface of the latch sleeve 266 in the latch sleeve through bore, with the latching seat 285 secured by one or more latching seat shear pins 287 . When latching the male disconnect member 205 with the female disconnect member 215 , the latching ball 286 may sealing engage the latching seat 285 in order that the latch sleeve, may axially move from a collet unlatch position to a collet latch position after shearing the first set or the portion of the double shear pin 269 extending through shear pin retainer 268 into the annular groove in the outer surface of the latch sleeve 266 . Shearing the one or more latching seat shear pins 287 may provide means for ejection of the latching seat 285 and latching ball 286 from within the latch sleeve 266 after movement of the latch sleeve 266 from the collet unlatch position to the collet latch position. The upper end of a latch sleeve extension tube 280 may be secured to the lower end of the latch sleeve 266 to receive and retain the latching seat 285 and latching ball 286 after the latching seat 285 and latching ball 286 are sheared and ejected from within the latch sleeve 266 . A plurality of slots or ports 282 may be provided in the latch sleeve extension mandrel 280 to allow circulation of fluid within the through bore of the drill pipe string 36 . A ball and seat catcher 284 may be provided near the lower end of the latch sleeve extension tube 280 to catch and retain the ejected latching seat 285 and latching ball 286 within the latch sleeve extension tube 280 , as illustrated in FIG. 16 . Alternatively, the latch sleeve 266 may be furnished with an integral non-shearing latching seat 266 and with no latch sleeve extension mandrel 280 . When employing this version of a latch sleeve, the latching ball 286 may be flowed to the surface by reverse circulating fluid after shifting the latching sleeve from the unlatch position to the re-latch position. Drill Pipe Disconnect and Reconnect Operation Referring to FIGS. 1 and 10 through 16 , in the preferred first embodiment for initial installation of the drill pipe disconnect 30 , the male disconnect member 205 and female disconnect member 215 may be connected as illustrated in FIG. 10 , excluding the unlatching ball 208 , and installed in a drill pipe string 36 . The latch sleeve 216 may be axially positioned such that the collet dogs 232 are engaged in the collet engagement groove 239 , thereby securing the male drill pipe disconnect member 205 with the female drill pipe disconnect member 215 . The axial position of the latch sleeve is secured by one or more shear pins 220 . The drill pipe disconnect 30 may be positioned at an axial point in the drill string from which it may be desirable to disconnect, such as below a subsurface riser disconnect assembly 10 , below a subsurface riser valve assembly 20 , or above a trouble spot in a wellbore where it may be desirable to disconnect an upper portion of the drill pipe 236 from a lower portion of the drill pipe 240 . To disconnect the male disconnect member 205 from the female disconnect member 215 , the collet mechanism unlatches. Fluid may be circulated through the wellbore WB sufficiently to remove cuttings and other debris. The drill pipe disconnect may be manipulated with the drill pipe set off on bottom, or suspended off bottom in the wellbore by the upper portion of the drill string, thereby allowing the lower disconnected portion of drill pipe to fall subsequent to disconnection. In a preferred embodiment, an unlatching ball 208 may be dropped from the drilling rig DR, through the through bore of the upper portion of drill pipe 236 to sealingly seat on the unlatching seat 209 , on a substantially top surface of the latch sleeve 216 . Pressure may be applied by the drilling rig DR to the through bore of the upper portion of drill pipe 236 to a first release pressure which creates sufficient axial force upon the latch sleeve 216 to shear pins 220 between male drill pipe disconnect housing 212 and latch sleeve 216 to axially move the latch sleeve downward from a collet latch position to a collet unlatch position. In the collet unlatch position, the plurality of collet dogs 232 may move radially inward within the circumferential collet unlatch groove 224 , thereby allowing the male disconnect member 205 to be telescopically removed from the female disconnect member 215 . The upper portion of drill pipe 236 may then be recovered to the drilling rig while leaving the lower portion of drill pipe 240 within the well bore WB. To avoid pulling a “wet string,” a drain groove 213 may be provided in the upper portion of the upper latch sleeve housing 210 and one or more drain ports 211 may be provided in the upper portion of the latch sleeve 216 to allow fluid in the upper portion of drill pipe 236 to drain while the upper portion of drill pipe 236 is being removed to the drilling rig DR. In a subsea installation, a subsea riser valve may be closed above the female disconnect member 215 in order to confine pressure and fluid with the wellbore WB. In addition, a subsea riser disconnect assembly 10 may be disconnected such that the upper riser 35 may be recovered to the drilling rig DR or the rig may be moved with the upper riser suspended below the drilling rig DR. To reconnect the upper portion of drill pipe 236 with the lower portion of drill pipe 240 , the male disconnect member 205 may be replaced or redressed with male reconnect member 225 as described previously. The replaced male reconnect member 225 may be telescopically inserted into the female disconnect member 215 , as illustrated in FIG. 13 , excluding the latching ball 286 . During such insertion, the collet dogs 232 may be recessed into the collet unlatch groove 224 on an outer surface of the latch sleeve 266 . The latch sleeve 216 in the male reconnect member 225 may be properly, axially positioned in the unlatch configuration by engagement of upper surface 273 on the outer surface of the latch sleeve 216 and a lower surface of the shear pin retainer 268 . During the telescopic insertion of the male reconnect member 225 into the female disconnect member 215 , the male non-rotational engagement member 226 may telescopically engage the female non-rotational engagement member 227 to facilitate unitary rotation of the drill pipe string 236 , 240 . To latch the male reconnect member 225 with the female disconnect member 215 , a latching ball 286 or other closure device, may be dropped or otherwise deployed from the drilling rig DR, through the through bore of the upper portion of drill pipe 236 to sealingly seat on the latching seat 285 . Pressure may be applied to the fluid in the through bore of the upper portion of drill pipe 236 , upon the latching ball 286 and latching seat 285 , to a latching pressure. The latching pressure is sufficient to shear a first shear position on the double position shear pin 269 or first set of separate shear pins, between the latch sleeve and shear pin retainer ring 268 . When the first shear position on the double shear position shear pin 269 shears, or the first set of separate shear pins shears, the latch sleeve 266 may axially move downward from the collet unlatch position to the collet latch position. Downward movement of the latch sleeve 266 may be arrested when the first shear pin retainer groove upper stop surface 264 interferes with or engages the upper retainer ring stop surface 262 . At such axial position of the latch sleeve, the collet latch surface 263 on the outer surface of the latch sleeve 266 may engage an inward portion of each collet dog 232 , causing each collet dog 232 to remain positioned radially outward and engage the collet unlatch groove 224 . The collet dog stop surface 233 engages the collet dogs 232 to prohibit axial separation of the male reconnect member 225 and the female disconnect member 215 , and the load bearing shoulder at the bottom of collet dogs 232 may engage a load bearing upper side of the collet engagement ring 237 portion of the latch mandrel 222 , thereby securing the male reconnect member 225 with the female disconnect member 215 . After latching the collet mechanism 230 , pressure in the upper drill pipe 236 through bore may be further increased from the latching pressure to a ball and seat ejection pressure. The ball and seat ejection pressure may be sufficient to cause the axial downward force upon the latching ball 286 and latching seat 285 to shear the latching seat shear pin 287 . When the latching seat shear pin 287 is sheared, the latching seat 285 and latching ball 286 may move axially downward through the through bore in the lower portion of the latch sleeve 266 , out of the lower end of the latch sleeve 266 , through an upper portion of the latch sleeve extension tube 280 and into a lower portion of the latch sleeve extension tube 280 . The ejected latching ball 286 and latching seat 285 may be caught within the lower portion of the latch sleeve extension tube 280 and retained therein by the ball and seat catcher 284 . One or more ports 282 through the latch sleeve extension tube 280 may permit transmission of fluid through the drill pipe 36 and drill pipe disconnect 30 through bore, to a bit or other tool on the lower end of the drill pipe 36 . As an alternative to shearing the latching seat 285 and latching ball 286 and ejecting the same into latch sleeve extension tube 280 , the ball 286 may be recovered to the surface by other means, such as reverse circulating fluid or with tools, prior to shearing the seat 285 . Such configuration thereby represents the normal operating configuration for a preferred embodiment of the drill pipe disconnect 30 , after reconnection of the male reconnect member 225 with the female disconnect member 215 . To disconnect the drill pipe disconnect 30 a second time, as illustrated in FIG. 16 , a reunlatching ball may be dropped through the through bore in the upper portion of drill pipe 236 for sealingly seating on the re-unlatching seat 259 , the re-unlatching seat positioned substantially on an upper surface of the latch sleeve 266 . Pressure may be applied in the through bore of the upper portion of drill pipe 236 to a re-unlatching pressure. The re-unlatching pressure may be sufficient to cause the axial downward force on the re-unlatching seat 259 and re-unlatching ball 258 to shear the second set of separate shear pins or the double shear position shear pin at the second shear position. When the second separate set of shear pins or the double shear position shear pin 269 is sheared at the second shear position, the latch sleeve may move axially downward from a collet latch position to a collet re-unlatch position. In the collet re-unlatch position, the collet dogs 232 may be aligned with the collet re-unlatch groove 274 such that the collet dogs may move radially inward toward the latch sleeve 266 and partially recess in the collet re-unlatch groove 224 . Downward movement of the latch sleeve may be arrested by engagement of the lower retainer ring stop surface 271 with the latch mandrel upper stop surface 270 . The male reconnect member 225 may be telescopically withdrawn from the female disconnect member by axial tensile force at the drilling rig DR, permitting recovery of the upper portion of drill pipe 236 to the drilling rig DR. Alternative embodiments for the drill pipe disconnect may provide components and means for manipulating components similar to the latch sleeve 216 or 266 other than balls and seats, and hydraulic pressure, such as by mandrel or bars on wire line, or other wireline conveyed tools. Recovery of balls or other manipulating devices may be employed to avoid leaving a ball in the drill pipe disconnect during well drilling or operations, or when pulling the upper portion of drill pipe 236 after disconnecting, to avoid recovering a “wet string.” An alternative embodiment functions by dropping a retrievable device to seal on one or more of the seats for manipulation of the latch sleeve 216 , 266 , which may thereafter be retrieved on wireline to avoid leaving a latching ball in the drill pipe disconnect 30 . A dart or standing valve may alternatively be dropped in lieu of a ball. An embodiment may include means for recovering the latching ball after manipulation of the latch sleeve 266 , such as with a magnet or by reversing fluid flow to retrieve the ball in a catcher or basket for ball retrieval. The drill pipe disconnect 30 may be manipulated between latched and unlatched positions, with the drill pipe string 36 set off on bottom of the well bore WB. Also, the drill pipe disconnect 30 may be manipulated between latched and unlatched positions with the drill pipe suspended off of bottom of the well bore WB, in the well bore WB. The weight of the drill pipe suspended below the disconnect may merely require additional hydraulic pressure to disconnect when the drill pipe is suspended off bottom of the well bore WB. In alternative embodiments for the drill pipe disconnect 30 , the collet mechanism may be replaced with a different mechanical or hydraulic latch mechanism, such as a grapple type mechanism. Also, the male disconnect member 205 , 225 and female disconnect member 215 may be inverted such that the male disconnect 205 , 225 may be secured to the lower portion of drill pipe 240 and the female disconnect member 215 may be secured to the upper portion of drill pipe 236 . Alternative embodiments may also be assembled with components which interconnect by means other than generally male and female interconnecting components. The drill pipe disconnect 30 is generally applicable to drilling wells both onshore and offshore. In addition, although the drill pipe disconnect device is generally referred to herein as a drill pipe disconnect, this device may also be employed with drill pipe used in work over operations, with a “work string” that is generally tubular. The drill pipe disconnect may be positioned below a BOP stack to facilitate disconnecting the drill pipe at a location in the drill string which may be relatively close to the rig, such that subsequently, blind rams may be closed, thereby sealing the interior of the well bore below the BOP stack. Such time saving option may be desirable in a well control situation. Such action may also minimize the amount of pipe that must be tripped out of the well to the rig floor. The drill pipe disconnect device may be alternatively adapted for use in setting liners or other downhole tubular members wherein it may be desirable to reliably disconnect an upper portion of tubulars from a lower portion of tubulars to leave the lower portion of tubulars within the wellbore. The disconnect device as disclosed herein may also be usefully employed as a safety device for drilling in high risk environments where the risk of sticking pipe, collapsing a well bore, key-seating the drill pipe in the well bore or other drilling hazard risks losing a lower portion of the pipe in the hole. In such instances, this device may be positioned within the tubular string such that the disconnect device may remain above the hazard point to provide a quick and reliable disconnect point uphole from the hazardous well bore region. Non-rotational engagement may be alternatively provided by components other than male and female engaging components, such as interlocking keys, dogs or otherwise. Where male and female non-rotational components engaged, the male component may be secured to either the upper portion of drill pipe or to the lower portion of drill pipe, with the female non-rotational engagement component secured to the other of the upper and lower portion of drill pipe. The drill pipe disconnect may provide the ability to further extend an “extended reach” well bore beyond the point at which all of a drill pipe string may be recovered to the rig by tensional force. In such instance where an open-hole completion may be economically feasible, a lower portion of the drill pipe string may be abandoned within a lower section of the well bore, and the upper portion of the drill string recovered. An alternative embodiment of the drill pipe disconnect may provide for manipulating a latch sleeve by a mechanism other than hydraulically with balls and seats. A latch sleeve may be manipulated by a standing valve, dart or rod that may sealingly engage a seat for hydraulic manipulation of the latch sleeve. Such standing valve, dart or rod may be recoverable on wireline or otherwise, such as reverse pumping the component out of the drill pipe string. A weight bar or rod may engage a load bearing shoulder with sufficient mass weight force to manipulate the latch sleeve. Alternative embodiments may eliminate the latch sleeve altogether and provide for a collet or other latch and unlatch mechanism which does not require a latch sleeve component to effect engagement of the upper and lower disconnect members. An embodiment of a drill pipe disconnect may be provided which eliminates the latch seat, latch ball and extension tube, thereby providing an open through bore, through the disconnect tool. Such open through bore may provide access for tools, instruments and materials which would not other wise pass through the ports in the extension tube, to pass through the disconnect device to the lower portion of drill pipe. Shear pins may be eliminated in favor of other retainer and release components. The drill pipe disconnect may be configured for manipulation between latch and unlatch positions by a combination of axial, rotational and hydraulic forces. Alternative embodiments may also be configured which provide for replacement of each double shear pin with two separate shear pins. The embodiments described herein and other embodiments of this invention are disclosed in an absence of hydraulic lines between these embodiments and a drilling rig. It is a significant benefit of this invention that hydraulic lines between the rig and downhole assemblies may be omitted. It may be appreciated by one skilled in the art that hydraulic lines may alternatively be provided for various uses or applications, including the disclosed assemblies or embodiments, or with other components or assemblies employed in conjunction with these embodiments. For example, an application for concurrently employing hydraulic lines in conjunction with employment of one or more of the disclosed assemblies may be elected in a shallow water installation, or to provide additional manipulating force to a riser valve sealing member to shear drill pipe. Hydraulic lines are not intended for preclusion from use, however, the disclosed embodiments may provide a more attractive alternative which permits excluding hydraulic lines. It may be appreciated that various changes to the details of the illustrated embodiments, methods and systems disclosed herein may be made without departing from the spirit of the invention. While preferred embodiments of the present invention have been described and illustrated in detail, it is apparent that still further modifications and adaptations of the preferred and alternative embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention, which is set forth in the following claims.	A subsea riser disconnect assembly 10 may be actuated from a drilling rig DR by axial movement of an upper riser 35 relative to a lower riser 28 , for disconnecting the upper riser 35 from the lower riser 28 . A subsea riser valve assembly 20 may be actuated from the drilling rig DR by axial movement of the upper riser 35 relative to the lower riser 28 , for sealing an interior portion of the lower riser 28 and well bore WB below the subsea riser valve assembly 20 . A drill pipe disconnect 30 may be actuated from a drilling rig DR, either onshore or offshore, for disconnecting an upper portion of drill pipe 236 from a lower portion of drill pipe 240 . The drill pipe disconnect 30 may be actuatable by hydraulic and/or mechanical forces applied to the drill pipe disconnect 30 from the drilling rig DR. The drill pipe disconnect 30 may be compatible for use with or without the subsea riser disconnect assembly 10 and/or the subsea riser valve assembly 20 . The component assemblies of this invention may improve the efficiency and lower the cost of recovering hydrocarbons by reducing drilling costs and time requirements. Also, the ability to relatively quickly disconnect a floating rig from a well may enhance the safety of persons and equipment facing hostile weather conditions or other emergency situations.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION The present invention relates to rotary drill bits for drilling boreholes into subterranean formations. More particularly, the invention relates to method of forming diamond elements for use in a novel rotary bit design utilizing diamond cutting elements. Drill bits utilizing diamonds or similar hard cutting elements are commonly employed in drilling and coring operations, particularly in hard subterranean formations such as chert, quartzitic sandstones or the like. The construction of such diamond drill bits usually includes a body portion having means for interconnection of the bit onto a drill string, and a matrix portion for mounting the diamonds or other cutting elements. Drilling fluid is directed down to the bottom of the borehole through the drill string and from a port generally disposed in the central portion of the bit. Fluid passageways or water courses that cross the drilling surfaces of the bit are also provided to transport this drilling fluid across the bit face to cool and lubricate the drilling surface of the bit and to facilitate movement of drill cuttings from the drilling area. The general theory of diamond bit operation is not simply to crush the formation and thereby make drilling progress, but rather to create tiny fractures as the cutting elements pass over the formation so that drilling fluid which is maintained at a higher pressure than the formation pressure, can enter these fractures and remove the fractured portions of the formation. While most diamond bits use this crushing or fracturing action to create the hole, some bits have been developed which utilize a shearing action to cut through the formation. Many different types of "diamond" cutting elements have been developed and used. These include natural diamonds, synthetic diamonds, and composites which include combinations of diamonds with other compounds such as tungsten carbide. Additionally, many different types of diamond shapes have been used. These include natural round stones, mechanically and chemically rounded and polished stones, natural cubic stones and natural octahedral stones. These stones have been inserted in many different configurations in diamond drill bits and in bits of many different shapes. Although diamond drill bits are the best type of bit for hard formations, their penetration rate is lower than other types of bits since they generally have to rely on crushing and fracturing action to cut through the formation. Accordingly, it would be a significant advancement in the art to provide a diamond drill bit which retains the advantages of having the hard diamonds as the cutting elements while providing a means for increasing the penetration rate of the bit. Such a bit is disclosed and claimed herein. SUMMARY OF THE INVENTION The present invention provides a novel drill bit which utilizes hemispherically shaped diamond inserts having a cleaved face to cut through rock formations. The diamond inserts can be formed by cleaving round diamonds in half. Alternatively, the diamond inserts can be formed by polishing and cleaving diamonds having other shapes. In a preferred embodiment, the diamond inserts are formed from various shapes of natural diamonds. A diamond is selected and studied to determine the cleaving plane and its perpendicular axis. The diamond is then cut along two planes parallel to the central cleaving plane. The diamond is then polished to form a cylinder having as its axis, the axis perpendicular to the cleaving plane. One end of the cylinder is then further polished to form a series of conical sections havign different angles to approximate a hemisphere. The diamond can then be cleaved to form a hemisphere. Depending on the shape and size of the diamond, the cleaved plane of the hemisphere may be the same as or parallel to the central cleaving plane. The drill bit comprises a body portion having a matrix for holding the diamonds in place. Passageways are created across the face of the matrix to allow drilling fluid to cool and lubricate the bit and carry cuttings away. These passageways divide the face of the drill bit into a plurality of fins. A plurality of hemispherically shaped diamond cutting elements are mounted in each of the fins. The hemispherically shaped diamond cutting elements are embedded in the matrix of the bit such that a portion of the cleaved, planar face of each element is exposed. The elements are positioned such that they have a leading edge in the direction of rotation of the bit and an outer edge which is distal from the matrix. The leading edge is inclined downward at a first angle α from a plane normal to the face of the bit and parallel to the direction of rotation to create a pitch. The outer edge is inclined downward at a second angle β from a plane normal to the face of the bit and parallel to the intersection of the planar face of the diamond element with the face of the bit. The diamond edge penetrates and fractures the formation progressively and at the same time removes the fractured cuttings by grooving with the rotation of the bit. The pressure on the diamond is directed on the cleaved face which provides the maximum resistance without damaging the diamond. The angle of inclination to create the pitch can be varied within suitable ranges depending upon the type of formation in which the bit will be used. For example, in extremely hard formations, the angles are smaller such that less material is removed with each rotation of the bit. For bits which are used in softer formations, the angles can be increased to provide for greater penetration rates. When the diamond inserts are formed from a series of conical sections approximating a sphere, the points between adjacent sections help anchor the inserts in the matrix. Since the forces exerted on the diamond elements are only applied to one edge of the face, a torque is created which tries to turn the elements in the matrix. The sharp points between conical sections help resist the forces that are trying to turn the elements. In the preferred embodiment, a plurality of fins are provided and only a single row of diamond cutting elements is arranged in each fin. However, it is also possible to provide arrangements with diamond cutting elements side-by-side, provided that the cutting surfaces of the diamonds are properly aligned. The grooving action of the cleaved diamonds can complete the fracturing of the debris and remove the fractured pieces which are held in place by the hydraulic pressure of the drilling mud in addition to simply fracturing the rock formation. One advantage of the drill bit of the present invention is that it provides faster penetration rates than conventional diamond drill bits. The cutting action of the hemispherically shaped diamond inserts which slice and groove into the formation creates a borehole faster than the crushing and fracturing action of the prior art drill bits. A further advantage of the present invention is that the diamond cutting elements can be recycled by removing them from the matrix and rotating them such that a new edge of the hemisphere is exposed. Another advantage is that the major cutting forces are applied to the cleaved face of the diamond. These and other advantages of the present invention will be more fully apparent from the following description and attached drawings taken in conjunction with the claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a drill bit embodying the present invention; FIG. 2 is a plan view of the crown end of the drill bit of FIG. 1; FIGS. 3 and 3A are perspective views of a slice of the bit illustrated in FIGS. 1 and 2; FIGS. 4 and 4A-4C are schematic views illustrating the orientation of the diamond inserts in the matrix of the bit; FIG. 5 is a partial cross-sectional view of the bit of FIGS. 1 and 2; FIG. 6 is a plan view of the crown end of a second preferred embodiment of the present invention; FIG. 7 is a partial cross-sectional view of the bit of FIG. 6. FIG. 8 is a perspective view of the center cutting element of the bit of FIGS. 6 and 7. FIG. 9 is a bottom plan view of the element of FIG. 8. FIG. 10 is a cross-sectional view taken along line 10--10 of FIG. 4A showing the grooving action of the diamond inserts of the present invention. FIG. 11 is a plan view of a tool used to form a mold for casting the bit of the present invention. FIGS. 12A-12E are schematic illustrations showing the steps involved in forming diamond inserts according to a preferred embodiment of the invention. FIG. 13 is a cross-sectional view of a portion of a drill bit showing the insert of FIG. 12E embedded within a matrix. FIG. 14 is a plan view of the cleaved face of a diamond insert according to a preferred embodiment of the invention. FIG. 15 is a perspective view of a portion of a mold showing the formation of holes to receive a diamond insert. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a novel design for a drill bit which utilizes cleaved, hemispherically shaped diamond cutting elements to provide a bit having increased penetration rates. Referrence is now made to the drawings in which like parts are designated with like numerals throughout. Illustrated in FIGS. 1 and 2 is a drill bit 10 of the type which may be constructed in accordance with the instant invention. Drill bit 10 comprises a body 12 formed of suitable material to withstand stress during operation. The upper portion of the body is provided with an exteriorly threaded neck 14 so that the bit 10 may be interconnected at the bottom of a drill string. The lower body section or crown 16 of the bit 10 is surfaced with a metal matrix 18 in which the diamond cutting elements 20 may be embedded. The matrix is a relatively hard, tough material such as bronze, or a similar metal alloy such as copper nickel alloy containing powdered tungsten carbide in quantities sufficient to convey the required strength and erosion resistance. Alternatively, the matrix may be composed of a suitably hard plastic material capable of being cast upon the bit and having the properties of resisting wear and retaining the cutting elements. The material is of a suitable thickness to provide the required strength, resistance to erosion and abrasion, and to embed the diamond cutting elements firmly therein. In casting the matrix material upon the bit body 12, it is common to provide recesses or a roughened surface on the bit body so that the matrix material will rigidly and firmly anchor to the bit body and form a permanent and fixed part of the drill bit. In the embodiment illustrated in FIG. 1, the matrix of the drill bit is shaped to have a generally semitoroidal end face defining an outer cylindrical gauge face 22, a lower, generally curved drilling face 24, and an interior coring face 26. The interior face 26 opens into a central passageway 28 extending through the bit body, and through which drilling fluid is directed down the drill string to the formation and across the face of the bit. Matrix 18 is formed such that it has a plurality of fins 30 into which the diamond cutting elements 20 are embedded. Fins 30 define a plurality of channels or water courses 32 which extend outwardly from the central passageway in the interior face, across the drilling face and up the gauge face of the bit. Accordingly, drilling fluid delivered through the drill pipe through passageway 28 is distributed through these flow passageways or water courses 32 to wash cuttings from the drilling area and upwardly to the top of the well as is well-known in the art. Additionally, in the embodiment illustrated, the matrix of the bit is provided with a series of junk slots 34 which are designed to discharge cuttings from the drilling area. It should be noted that a number of other configurations suitable for use in a diamond drilling bit would be obvious to those skilled in the art. As can be best be seen in FIG. 5, a pair of hemispherically shaped diamond cutting elements 33 are placed in a projection 35 in central passageway 28. Cutting elements 33 remove the core that is formed as drilling face 24 progresses through the formation. Reference is next made to FIGS. 3, 3A, 4 and 4A-4C which illustrate the manner in which diamond cutting elements 20 are embedded in the matrix 18 in accordance with the teachings of the present invention. Cutting elements 20 have a hemispherical shape and a planar surface 38 formed by cleaving a diamond. In one embodiment, cutting elements 20 are obtained by cleaving a round diamond in half. As can best be seen in FIG. 4A and 4C, diamond cutting elements 20 are embedded in matrix 18 such that the center 21 of each element 20 is behind face 19 of matrix 18. Accordinglty, slightly over half of each cutting element 20 is embedded within the matrix to ensure that the elements are securely fixed in place. Diamond cutting elements 20 are oriented within matrix 18 of fins 30 to provide the optimum cutting surface. Generally, the rounded surface of cutting element 20 is oriented toward the lowermost tip 31 of fin 30. The orientation of elements 20 can best be seen with reference to FIGS. 4 and 4A. Illustrated in FIG. 4 are lines X--X', Y--Y' and Z--Z' which are oriented at 90 degrees to each other to define a three dimensional space and which intersect each other at center 21 of diamond element 20. The plane defined by Lines Y--Y' and Z--Z' is parallel to face 19 of fin 30 with line Y--Y' passing through the center 21 of diamond element 20. It should be appreciated that while line Y--Y' has been shown as a straight line for purposes of illustration in FIG. 4A, it is parallel to face 19 of fin 30 and will be a curved line where face 19 is curved. Line X--X' is perpendicular to face 19 of fin 30. The flat or planar surface 38 which is defined by the cleaved face of element 20 is rotated in two directions with respect to the plane defined by lines X--X' and Z--Z'. First, as shown in FIG. 4B, leading edge 40 of element 20 is inclined downward around the X--X' axis at a first angle α as illustrated by line P--P' to create a pitch. This permits cutting element 20 to groove down into the rock formations. Angle α can be increased or decreased depending upon the type of formation in which the bit will be used. Generally, angle α is within the range of 30-60 degrees. Preferably, angle α is about 45 degrees. The outer edge 44 of diamond cutting element 20 is also inclined downward around the P--P' axis from a plane defined by lines X--X' and P--P' at a second angle β as illustrated by line W--W' in FIG. 4. This downward inclination exposes the sharp cutting edge 44 and planar surface 38 of cutting element 20 to the formation being drilled. If angle β is formed before angle α, the rotation occurs around the Z--Z' axis as illustrated in FIG. 4C. Angle β can also be adjusted within a suitable range depending upon the size of the cutting element and the hardness of the formation in which bit 10 will be used. Generally, angle β is within the range of 15-30 degrees. Preferably, angle β is about 30 degrees. As can be seen from the foregoing, lines P--P' and W--W' define the planar surface 38 of element 20. This plane is rotated in two directions from the plane defined by lines X--X' and Z--Z' if angle β is created first. Otherwise, angle β is measured from the plane defined by lines X--X' and P--P'. As can be seen in FIGS. 3 and 3A, the orientation of diamond cutting elements changes as they progress from the outer face to the interior face of bit 10. The greatest change occurs adjacent lowermost tip 31 of fin 30. Reference is next made to FIGS. 6-9 which illustrate another preferred embodiment of the present invention. In this embodiment, fins 30 are substantially identical to the embodiment illustrated in FIGS. 1 and 2. A core cutting insert 46 is provided at the center of central passageway 28 to remove the core which is left as the formation disk shaped with crossbars 48 and openings 49 formed in the center thereof. Insert 46 is positioned in central passageway 28 and is secured in place by threaded ring 51. Openings 49 permit drilling fluid to pass through insert 46 to clean and lubricate the face of bit 10. The upper edges of crossbars 48 are tapered to create as little turbulence as possible as the fluid passes through openings 49. A pair of notches 50 are formed in the bottom of insert 46 to permit east alignment of insert 46 within central passageway 28. The notches 50 also help prevent rotation of insert 46 within bit 10. A pair of diamond cutting elements 52 and 54 are positioned in crossbars 48 for removing the core. Diamond cutting elements 52 and 54 are generally hemispherical in shape and are formed by cleaving generally round diamonds in half. The flat faces 56 and 58 of elements 52 and 54 are positioned such that they face each other. However, elements 52 and 54 are offset such that they only slightly overlap each other. When diamond cutting elements 52 and 54 become worn or break, insert 46 can easily be removed and replaced. Because the core is not supported, it is easily destructed in small fragments without retartding the penetration of the bit. Reference is next made to FIG. 10 which illustrates the cutting and grooving action of diamond cutting elements 20. As planar surface 38 of cutting element 20 engages rock formation 60, it fractures and grooves the rock thus forming pieces 62 which are carried away by the drilling fluid. A groove 64 is formed in rock formation 60 by the cutting action of element 20. As can further be seen in FIG. 10, only an outer portion 39 of element 20 engages rock formation 60. Accordingly, a space 61 remains between matrix 18 of the bit and rock formation 60. This provides a passageway for removal of chipped rock. The diamond inserts of the present invention have an advantage over PDC cutters since the inserts are formed from a single crystal. Heat generated while cutting a rock formation is more readily dissipated throughout the diamond and into the bit matrix. This prolongs the life of the cutter. FIG. 11 illustrates a tool 66 which can be used in the formation of a mold for casting bit 10. Generally, diamond bits are formed by mounting the diamonds in a graphite mold which is then filled with a metal powder that is sintered to form the matrix which holds the diamonds. Tool 66 includes a hemispherically shaped body 68 which is covered with a plurality of cutting blades 70. A ring 72, also covered with cutting blades is formed adjacent planar face 74 of body 68. Body 68 is mounted on a shaft 76 for attachment to a suitable mill. Tool 66 is rotated by the mill and cuts a portion of a hemispherically shaped hole in the graphite mold into which diamond cutting elements 20 can be mounted. Since the edge of body 68 adjacent planar face 74 tends to wear first, ring 72 is provided to create a slightly larger opening adjacent the planar face. This ensures that the hole created by tool 66 is properly sized to receive the diamond cutting element 20, especially the sharp edge adjacent the cleaved face. FIG. 15 illustrates the cutting of holes 120 in a mold 122 using tool 66. Mold 122 corresponds to the face of a fin 30. Shaft 76 of tool 66 is attached to a suitable mill which can be programmed to cut holes 120 having a planar surface 123 corresponding to the cleaved face of the diamond inserts and a concave surface 124 corresponding to the curved portion of the hemispherically diamond inserts. The axes of the hole 120 are shown by lines X--X', Y--Y', Z--Z', P--P' and W--W' which correspond to the axes illustrated in FIG. 4. As tool 66 cuts holes 120, it moves along a plane defined by lines P--P' and W--W'. Methods of clamping mold 122 and programming a suitable mill are well known to those skilled in the art. FIGS. 12A-12E illustrate a method whereby hemispherical inserts whithin the scope of the present invention can be formed from diamonds which are not round. In this process, a generally round diamond 80 is studied to determine a central cleaving plane 82 and the perpendicular axis 84 as shown in FIG. 12A. The diamond is then cut along two planes 86, 88 which are parallel to cleaving plane 82 as shown in FIG. 12B. Diamond 80 is then rotated about axis 84 and polished as shown in FIG. 12C to form a cylinder 90. Cylinder 90 is then polished on one end is a series of steps to form a series of conical sections 92, 94, 96 as shown in FIG. 12D to approximate a hemisphere. While the illustrated embodiment shows three conical sections, it will be appreciated by those skilled in the art that different numbers of sections could be used and the angle of each section with respect to the axis 84 could be varied. The determination of the proper angles is within the level of skill in the art. Diamond 80 is then notched at 97 and 99 so that it can be cleaved along plane 98 to form a hemisphere 101 as illustrated in FIG. 12E. Depending upon the shape of diamond 80 and the length of cylinder 90 additional hemispheres can be formed from the same diamond by repeating the polishing and cleaving steps illustrated in FIGS. 12D and 12E. Any remaining portions of cylinder 90 can be cleaved to form diamond discs 100 as shown in FIG. 12D. These discs can be used in conventional diamond drill bits in place of synthetic diamond discs. The portion of diamond 80 that can be formed into discs 100 is used as a base to grasp the diamond as the conical sections are being polished. An advantage of this method of forming hemispherical diamond inserts can be seen in FIG. 13. A series of sharp ridges 102, 104, 106 encircling hemisphere 101 are formed between the various conical sections. When hemisphere 101 is cast into matrix 18, ridges 102, 104 and 106 help anchor the diamond and prevent it from rotating as forces are applied to the face of the diamond during use. A portion of mold 122 with hole 120 formed therein is also illustrated in FIG. 13. Cleaved plane 98 of hemisphere 101 is positioned along planar surface 123 of hole 120. Ridges 102 and 104 are positioned adjacent concave surface 124. Hemisphere 101 is glued into hole 120 to secure it in place while matrix 18 is being formed. Reference is next made to FIG. 14 which illustrates a plan view of plane 98 of the diamond illustrated in FIG. 12E. The face of hemisphere 101 can be divided into six sections 110-115. Opposing sections 110 and 113 include notches 97 and 99. The remaining four sections 111, 112, 114 and 115 include a clean outer edge that can be used as the cutting edge for the diamond insert. When the edges of the diamond cutting elements become dull, the diamonds can be removed, rotated and used in a new bit. As can be seen from the foregoing, the present invention provides a novel drill bit design which uses hemispherically shaped diamond inserts having a cleaved face as cutting elements. The inserts are positioned in the matrix of the bit to expose a sharp cutting surface which knives through the formation being drilled to provide faster penetration rates than other types of diamond drilling bits. The inserts can be formed by cleaving round diamonds in half or by polishing and cleaving diamonds to approximate a hemisphere. While the invention has been described with respect to the presently preferred embodiments, it will be appreciated that changes and modifications can be made without departing from the scope or essential characteristics of the invention. Accordingly, the scope of the invention is defined by the appended claims rather than by the foregoing description. All changes or modifications which come within the meaning and range of equivalency of the claims are to be embraced within their scope.	A method of forming hemispherically shaped diamond cutting elements for use in a rotary drill bit is provided. The method includes identifying a cleaving plane in a diamond and a perpendicular axis, polishing the diamond to form a series of truncated cones approximating a hemisphere around said axis, and cleaving the diamond to form a cutting face.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to collapsible structures, and in particular, to collapsible structures which incorporate the use or delivery of water. [0003] 2. Description of the Prior Art [0004] There are presently many collapsible structures that are being provided for use by children and adults in a number of different applications. Examples of these collapsible structures are illustrated in the following patents: U.S. Pat. Nos. 5,816,954 (Zheng), 6,006,772 (Zheng), 5,778,915 (Zheng), 5,467,794 (Zheng), 5,975,101 (Zheng), 5,722,446 (Zheng), 4,858,634 (McLeese), 4,825,592 (Norman), 5,964,533 (Ziglar), 5,971,188 (Kellogg et al.), 6,485,344 (Arias), 6,343,391 (LeGette), U.S. Pub. No. 2004/0139997 (Zheng) and U.S. Pat. No. 5,038,812 (Norman), among others. These collapsible structures are supported by one or more frame members that can be twisted and folded to reduce the overall size of the structure. These collapsible structures can be used in a wide variety of applications, such as containers, tents, play structures, executive toys, shelters, sports structures, and others. As a result, collapsible structures have become very popular. SUMMARY OF THE DISCLOSURE [0005] It is an object of the present invention to provide a collapsible structure that incorporates the use or delivery of water. [0006] In order to accomplish the objects of the present invention, the collapsible structure according to the present invention provides a structure having at least one foldable frame member having a folded and an unfolded orientation, with a fabric material covering portions of the frame member to form at least one panel when the frame member is in the unfolded orientation. A water tube is attached to the fabric material and connected to a water supply, and a water outlet is coupled to the water tube. BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG. 1 is a perspective view of a collapsible structure according to one embodiment of the present invention. [0008] FIG. 2 is a partial cut-away view of the section A of the structure of FIG. 1 illustrating a frame member retained within a sleeve. [0009] FIGS. 3A through 3C illustrate how the collapsible structure of FIG. 1 may be twisted and folded for compact storage. [0010] FIG. 4 is a cross-sectional view of the section 4 - 4 in FIG. 1 . [0011] FIGS. 5-6 illustrate other embodiments of collapsible structures according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0012] The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims. [0013] As shown in FIGS. 1 and 2 , a structure 20 is provided that comprises four panels 22 , 24 , 26 and 28 connected to each other to encircle an enclosed space. Each panel 22 , 24 , 26 , 28 can have four sides, such as a left side 30 , a bottom side 32 , a right side 34 and a top side 36 , although each panel 22 , 24 , 26 , 28 can assume any configuration and have any number of sides. Each panel 22 , 24 , 26 and 28 has a frame retaining sleeve 38 provided along and traversing the four edges of its four sides 22 , 24 , 26 , 28 . A frame member 40 is retained or held within each respective frame retaining sleeve 38 to support each panel 22 , 24 , 26 , 28 . Only the frame member 40 is shown in FIG. 2 ; the other frame members are not shown but are the same as frame member 40 . [0014] The frame members 40 may be provided as one continuous loop, or may comprise a strip of material connected at both ends to form a continuous loop. The frame members 40 are preferably formed of flexible coilable steel, although other materials such as plastics may also be used. The frame members should be made of a material which is relatively strong and yet is flexible to a sufficient degree to allow it to be coiled. Thus, each frame member 40 is capable of assuming two positions or orientations, an open or expanded position such as shown in FIG. 1 , or a folded position in which the frame member is collapsed into a size which is much smaller than its open position (see FIG. 3C ). [0015] Fabric or sheet material 42 extends across each respective panel 22 , 24 , 26 , 28 , and is held taut by the respective frame member 40 when in its open position. The term fabric is to be given its broadest meaning and should be made from strong, lightweight materials and may include woven fabrics, sheet fabrics or even films. The fabric should be water-resistant and durable to withstand the wear and tear associated with rough treatment. The frame members 40 may be merely retained within the respective frame retaining sleeves 38 without being connected thereto. Alternatively, the frame retaining sleeves 38 may be mechanically fastened, stitched, fused, or glued to the respective frame members 40 respectively, to retain them in position. [0016] FIG. 4 illustrates one possible connection for connecting adjacent edges of two panels 22 and 24 . The fabric pieces 42 are stitched at their edges by a stitching 44 to the respective sleeves 38 . Each sleeve 38 may be formed by folding a piece of fabric. The stitching 44 also acts as a hinge for the panels 22 and 24 to be folded upon each other, as explained below. The connections for the three other pairs of adjacent edges may be identical. Thus, the connections on the left side 30 and the right side 34 of each panel 22 , 24 , 26 , 28 act as hinge connections for connecting an adjacent panel. [0017] At the top side 36 and the bottom side 32 of each panel 22 , 24 , 26 , 28 , where there is no hinge connection to an adjacent panel, the frame retaining sleeve 38 may be formed by merely folding over the corresponding fabric piece and applying a stitching 46 (see FIG. 2 ). The fabric piece 42 for the corresponding panel may then be stitched to the sleeve 38 . [0018] Openings 48 and 50 may be provided in some or all of the panels 22 , 24 , 26 , 28 . These openings 48 and 50 may be of any shape (e.g., triangular, circular, rectangular, square, diamond, etc.) and size and can be designed to allow an individual to pass through them to, enter or to exit the structure 20 (among other functions). [0019] A plurality of tubes are provided on one or more of the panels 22 , 24 , 26 , 28 via stitching, glue or similar attachment means, or via removable attachment mechanisms such as hooks, straps, ties, VELCRO™ pads and the like. These tubes can be used to form tube systems for delivering water or other liquids to selected locations or outlets. For example, a tube 52 can have a first end 54 that extends away from the structure 20 for connecting to a water supply 56 , such as a water tap or faucet. The intermediate portion of the tube 52 can extend along a bottom side 32 of the panel 24 and then up along the sides 34 and 32 of the panels 22 and 24 , respectively, before traversing a portion of the fabric 42 of the panel 22 to a shower outlet 60 positioned above the opening 50 . The shower outlet 60 can have a plurality of spray holes to allow water to be sprayed like a mist on to any individual passing through the opening 50 . Another tube 58 branches off from the tube 52 along the fabric 42 of the panel 24 , then extends around the circular opening 48 , and then extends along the top sides 36 of the panels 24 and 22 to a shower head 62 . Spray holes 66 can be provided along the circular portion of the tube 58 to allow water to be sprayed like a mist on to any individual passing through the opening 48 . A branch of tubing 64 can connect the tubes 52 and 58 along the fabric 42 of the panel 22 . Thus, water can be delivered from the supply 56 through the tubes 52 , 58 to outlets such as the spray holes 66 , shower outlet 60 and shower head 62 . This water spraying ability can be both functional and for amusement. For example, the structure 20 can be placed around a sandbox or other location where it might be desirable for the individuals exiting that location to be washed or showered. [0020] The tubes 52 , 58 , 64 can be made from any conventional soft tubular material that allows water to flow therethrough without leaking. Examples include the materials used for garden hoses, among others. The material is preferably soft and flexible so that the tubes can be folded as the structure 20 is twisted and folded in the manner described below. [0021] While the structure 20 of FIG. 1 is shown and described as having four panels, each having four sides, it will be appreciated that the structure 20 may be made of any number of panels, each having any number of sides, without departing from the spirit and scope of the present invention. For example, each structure may have at least one panel (see FIG. 5 below), and each panel may have three or more sides. Thus, the structures of the present invention may take a variety of external shapes. However, each panel, regardless of its shape, is supported by at least one frame member 40 . [0022] FIGS. 3A through 3C describe the various steps for folding and collapsing the structure 20 of FIG. 1 for storage. The first step consists of pushing panels 22 and 24 towards panels 28 and 26 , respectively, about their hinged connections so that panel 22 collapses upon panel 28 and panel 24 collapses upon panel 26 . Then, the two panels 22 and 28 are folded so as to be collapsed upon the two panels 24 and 26 to form a stack of four panels, as shown in FIG. 3A . In the second step, the structure 20 is then twisted and folded to collapse the frame members 40 and panels 22 , 24 , 26 , 28 into a smaller shape. In particular, the opposite border 70 of the stack of panels 22 , 24 , 26 , 28 is folded in (see arrow 72 in FIG. 3A ) upon the previous fold to further collapse the frame members 40 with the panels. As shown in FIG. 3B , the folding is continued so that the initial size of the structure 20 is reduced until the frame members 40 and panels are collapsed on each other (see FIG. 3C ) to provide for a small essentially compact configuration having a plurality of concentric frame members 40 and layers of the panels 22 , 24 , 26 , 28 so that the collapsed structure 20 has a size which is a fraction of the size of the initial structure. [0023] FIG. 5 illustrates a modification of the structure 20 , where the new structure 20 a is essentially comprised of the panel 22 a , and the other panels 24 , 26 , 28 are omitted. The panel 22 a and its fabric 42 a , opening 50 a , tube 52 a , tube 58 a , shower head 62 a and shower outlet 60 a can be the same as the corresponding panel 22 and its fabric 42 , opening 50 , tube 52 , tube 58 , shower head 62 and shower outlet 60 . The structure 20 a further includes another shower outlet 74 a , and two hanging straps 76 a attached to the top side 36 a . The straps 76 a allow the panel 22 a to be suspended from the top edge of an open door, from the branches of a tree, or any other support member that would allow the panel 22 a to be suspended in a vertical manner. The panel 22 a can be folded and collapsed in the same manner as described above in connection with FIGS. 3A-3C . As with the structure 20 , the structure 20 a allows for a collapsible structure to incorporate water use or water play, where the ability of the structure 20 , 20 a to be reduced in size for storage promotes convenience and ease of storage. [0024] FIG. 6 extends the principles of FIGS. 1-5 to different types of collapsible structures. In FIG. 6 , the structure 100 does not have separate panels 22 , but is instead made up of two crossing frame members 102 , 104 that can be made of the same material as the frame member 40 described above. The frame members 102 , 104 cross at an apex 106 , and their respective ends are secured to the ground or surface, so as to form a domed or apexed configuration for the structure 100 . Fabric material, which is provided in the form of a shell 108 , is removably attached to the frame members 102 , 104 to form an enclosing structure. Frame retaining sleeves 110 and 112 can be stitched to the fabric shell 108 to retain the frame members 102 and 104 , respectively. Openings 116 and 118 similar to the openings 48 , 50 can be provided in the fabric shell 108 , and tubes 114 can be attached to the fabric shell 108 or the sleeves 110 , 112 to form tubing systems. For example, the tube 114 can have an end 120 that is adapted to be connected to a water faucet 122 . The tube 114 can be partially housed in its own sleeve 124 which is attached to (e.g., by stitching) and extends along the sleeve 110 , and then extends along the fabric shell 108 around the opening 116 , then along the bottom edge of the fabric shell 108 where it branches in three directions: towards a tubing section 126 (having spray holes) that encircles the opening 118 , towards a spray ring 128 , and towards a shower head 130 . The tube 114 can be made from the same material as the tube 52 . The structure 100 can be disassembled by removing and separating the frame members 102 and 104 , and then folding the fabric shell 108 . Since the tube 114 is flexible and soft, it can be folded together with the fabric shell 108 . [0025] While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.	A structure has at least one foldable frame member having a folded and an unfolded orientation, with a fabric material covering portions of the frame member to form at least one panel when the frame member is in the unfolded orientation. A water tube is attached to the fabric material and connected to a water supply, and a water outlet is coupled to the water tube.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION l. Field of the Invention The invention relates to a combination flow shut off valve and well condition sensing device for downhole installation in a well conduit immediate to a producing zone. 2. Description of the Prior Art. In the completion of oil or gas wells, it is essential that accurate measurements be taken of various parameters involved in the production zone, such as fluid pressure and temperature. Experience has shown that more reliable measurements are obtained when the condition sensing device is positioned closely adjacent the producing zone and upward flow of produced fluids is entirely shut off. Additionally, certain important operating parameters are best determined by measurements taken first after a flow shut off, then re-opening the shut off valve to permit fluid flow, then shutting off the flow and taking an additional set of measurements. Downhole shut off valves have heretofore been utilized but have been characterized by relatively complex structures requiring a plurality of trips into the well to install and a plurality of trips to remove from the well at the completion of the tests. There is, therefore, a distinct need for a downhole shut off valve operable in conjunction with a condition sensing device which can be installed in a single trip of an auxiliary conduit into the well. Where the sensing device is electric, it would be highly advantageous to accomplish the run-in and flow shut off with an electric wire line. SUMMARY OF THE INVENTION The invention provides a method of installing and operating a well condition sensing device, and an improved valving apparatus incorporating a well condition sensing device which can be installed in the wall with a single trip of an auxiliary conduit and operated by such auxiliary conduit. The fluid flow cut off apparatus is defined by a tubular outer body assembly within which a hollow mandrel is axially slidably mounted. An external annular elastomeric seal is provided on the tubular outer body to cooperate with a seal bore provided in the well tubing at a point immediately above a production zone. Such elastomeric seal is normally not in sealable contact with the seal bore but can be compressibly expanded to effect a sealing engagement with the seal bore by upward movement of the mandrel. Additionally, an internal annular seal bore or valve seat is provided in the outer body which is engaged by an annular seal on the hollow mandrel when it is moved to an upper position relative to the tubular body. Thus fluid flow around or through the tubular outer body is cut off. Typically, an electric well condition sensing device is mounted in the bore of the hollow mandrel and an electric wire line traverses the bores of the tubular outer body and is mechanically connected to the hollow mandrel and electrically connected to the electric well condition sensing device. The entire valving and sending apparatus is run into the well. on the electric wire line and, after being positioned in the well conduit at a point above the production zone through the operation of conventional radially shiftable lock elements, or by other similar and known means, the application of tension to the electric wire line will produce an upward movement of the hollow mandrel which will concurrently expand the external annular elastomeric seal on the tubular body assembly into engagement with the adjacent seal bore on the well conduit, such as a landing profile nipple, and effect a sealing engagement of the annular seal on the mandrel with the seal bore or valve seat. Preferably, a compressed helical spring is mounted between the tubular body assembly and the hollow mandrel to urge the hollow mandrel downwardly to its open flow position wherein fluid can flow through ports in the side wall of the tubular body, around the hollow mandrel and into the bore of the tubular body. With the described apparatus, the flow cut off valving mechanism and the sensing device can be concurrently run into the well on a conventional electric wire line, slick line, tubular member or other auziliary conduit, and the flow cut off device manipulated to its closed position through the application of a modes tension to the electric wire line. Subsequent application of fluid pressure to the well conduit above the valving device, and release of the tension on the electric wire line, will effect the return of the hollow mandrel downwardly to its flow open position. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A, 1B and 1C collectively represent a vertical cross sectional view of a well condition sensing device and valving assembly embodying this invention, shown in assembled relationship in a well conduit with the valving elements disposed in their open or flow position; FIGS. 1B and 1C being respectively vertical continuations of FIGS. 1A and 1B. FIGS. 2A, 2B and 2C are views similar respectively to FIGS. 1A, 1B and 1C, but showing the valving elements in their flow cut off position. DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, there is shown a well conduit 1 which extends into a production zone (not shown). The well conduit 1 may comprise a well casing or a liner, production tubing, and, in any event, constitutes the primary conduit by which production fluid from the well is transmitted to the surface. Well conduit 1 includes a special nipple section 2 threadably connected in the conduit string and defining at its upper end an outwardly facing, inwardly projecting, annular no-go shoulder 2a. Below the no-go shoulder 2a, the special nipple 2 is provided with a downwardly facing locking shoulder 2b above an annular recess 2c. Below the locking shoulder 2b, the special nipple 2 is provided with an extended length of seal bore surface 2d having a greater diameter than the minimum diameter of the no-go shoulder 2a. The combination well condition sensing device and flow cut off valve is represented generally by the numeral 10. Such assembly is run into the well on a conventional electric wire line 3, slick line, tubular member or other auxiliary conduit, the connection of which to the assemblage 10 will be hereinafter described. Assemblage 10 includes an outer tubular anchor housing assemblage 20, an annular elastomeric seal 26, a seal compression assemblage 30, and a hollow mandrel 40. Seal compression assemblage 30 is mounted for axially slidable movement relative to the outer tubular housing assembly 20 by an upwardly projecting sleeve 31 which slidably engages a bore portion 21 of the anchor housing assembly 20. The hollow mandrel assembly 40 is in turn slidably mounted within a downwardly extending sleeve 32 secured to the lower end of the annular seal compression assembly 30 for axial movements relative to the seal compression assembly. The upper end of the outer tubular anchor housing assembly 20 includes an anchor sub 22 which defines at its top end, a downwardly facing annular stop shoulder 22a which engages the no-go shoulder 2a of nipple 2 and positions the entire assembly 10 relative to the special nipple 2. Anchor sub 22 further includes a plurality of peripherally spaced, radially shiftable lock elements 23 which are of conventional construction and urged by springs (not shown) or other biasing means to a radially outer position so that when the lock elements 23 are positioned opposite the recess 2c immediately below the locking shoulder 2b, they will spring outwardly into engagement with recess 2c and thus restrain the entire assembly 10 from upward movement relative to the well conduit 1, as shown in FIG. 1A. Anchor sub 22 is connected by threads 22b to the upper end of a spacer sub 24 which in turn is connected by threads 24a to the upper end of a seal mounting sub 25. Seal mounting sub 25 defines an annular recess at its lower end to accommodate, in conventional fashion, an annular elastomeric seal 26. The diameter of seal 26 is selected to be less than the minimum diameter of the no-go shoulder 2a so that the seal 26 may readily pass such shoulder; however, the seal 26 is expandable through compressive forces produced by upward movement of the seal compression assembly 30 to expand such seal into intimate sealing engagement with the seal bore surface 2d of the special nipple 2. The seal compression assembly 30 includes a compression sub 33 which is threadably secured by threads 33b at its upper end to the guide sleeve 31 and by threads 33c at its lower end to the mandrel guide sleeve 32. Compression sub 33 includes an outwardly and downwardly inclined top surface 33a which engages a correspondingly shaped surface on the annular elastomeric seal 26. Hence, upward movement of the seal compression assembly 30 will effect a compression of annular seal 26 and an outward displacement of said seal into sealing engagement with the seal bore surface 2d. Additionally, the compression sub 33 is provided with a plurality of peripherally spaced radial equalizing ports 34 which provide communication to the annulus from the interior of the inserted assembly 10 and the bore 1a of the well conduit 1 to the interior bore of the inserted assembly for a purpose to be hereinafter described. The upstanding guide sleeve 31 is provided at its upper end with a radially enlarged shoulder portion 31a which cooperates with the upper end of the seal mounting sub 25 to limit the downward movement of the seal compression assembly. An internally projecting shoulder 24b provided on the spacer sub 24 limits the upward movement of the guide sleeve 31 relative to the anchor assembly 20. As previously mentioned, hollow mandrel assembly 40 is mounted within the bore of depending guide sleeve 32 for relative axial movements with respect to the compression sub 33. More specifically, a head portion 41 of the hollow mandrel 40 is provided with a reduced diameter axial bore 41a and an exterior enlarged shoulder portion 41b which slidably engages the internal bore surface 32a of guide sleeve 32. The limits of axial movement of head 41 are determined at the top by the compression sub 33 and at the bottom by an inwardly projecting shoulder 32b formed on the bottom end of the guide sleeve 32. A plurality of peripherally spaced radial fluid flow ports 32d are provided in guide sleeve 32 below the compression sub 33. In the open flow position of the mechanism shown in FIGS. 1A, 1B and 1C, produced fluid will flow upwardly around hollow mandrel assembly 40 and through ports 32d into the bore of anchor housing assembly 20 and thence through the bore of the well conduit 1 to the surface. The upper end of the head 41 of the hollow mandrel assembly 40 is provided with an upwardly facing sloped surface 41e which engages a correspondingly shaped downwardly facing surface 33d formed on the interior of the compression sub 33. The inter-engagement of these surfaces will cause the compression sub 33 to be moved upwardly by the hollow mandrel 40 to the fluid cut off position shown in FIGS. 2A, 2B and 2C. In this fluid cut off position, a pair of O-rings 46 mounted on the periphery of the head 41 of the hollow mandrel assembly 40 engage a seal bore or valve seat 33e defined in the compression sub 33. Fluid flow through the ports 32d is therefore effectively blocked from entering the bore of the hollow tubular assemblage 20. Concurrently, the annular elastomeric seal 26 is urged outwardly into sealing engagement with the seal bore surface 2d of the well conduit 1 to eliminate fluid flow around the inserted assemblage 10, as clearly shown in FIGS. 2A, 2B and 2C. The lower portion of the head 41 is provided with an enlarged counter-bore recess 41c within which is mounted an electric wire line anchor 42. The bottom end of the electric wire line 3 is mechanically secured in conventional fashion to the wire line anchor 42. Anchor 42 in turn is sealably mounted in the counter-bore recess 41c. Depending from the cable anchor 42 is a mounting tube 51 for supporting desired electric pressure and/or temperature sending devices 50 to determine the well conditions. Electrical connections (not shown) are provided in tube 51 for connecting the electrical conductors in electric wire line 3 to sensing devices 50. Devices 50 are of conventional construction and are of the type that are electrically actuated and produce electric signals. The necessary supply of current to devices 50 and the return of the electric signals generated to the surface is accomplished by the electrical conductors conventionally incorporated in the electric wire line cable 3. The lower end of head portion 41 is threadably secured as by threads 41d to the upper end of an externally threaded sleeve 43. An internally threaded spring anchor ring 44 is adjustably positioned on the external threads of sleeve 43. A compression spring 45 is mounted between anchor ring 44 and the bottom end of the depending guide sleeve 32, and thus imparts a downward bias to the hollow mandrel assemblage 40 urging it to the position shown in FIGS. 1B and 1C. While it is not essential, other types of mechanically actuated well condition sensing devices 60 may be mounted on the bottom end of sleeve 42 by being threadably connected to a thread cross-over sub 48. Such mechanically actuated pressure and temperature measuring devices may be provided as insurance against the failure of the electric type sensing devices 50. OPERATION In the operation of the described mechanism, the entire assembly including the electric sensing devices 50, the hollow mandrel assembly 40, the seal compression assembly 30 and the outer tubular anchor assembly 20 are lowered into the well on electric wire line 3. As mentioned, when the shoulder 22a on the anchor sub 22 of the outer tubular anchor assembly 20 seats on the no-go shoulder 2a in the special nipple 2, the locks 23 move radially outwardly into the aligned annular nipple recess 2c and are engagable with the downwardly facing nipple shoulder 2b to prevent further upward movement of the inserted anchor body assembly 20 relative to the well conduit 1. In the position of the apparatus shown in FIGS. 1B and 1C, well fluids can flow freely upwardly around the exterior of the hollow mandrel assembly 40 and enter the interior bore of the inserted assembly 10 through the peripherally spaced flow ports 32d provided in the ending guide sub 32. From this point, the fluid passes upwardly through the internal bore of the seal compression assembly 30 and the tubular anchor body assemblage 20. The applications of an upward tensile force to the electric wire line 3 will produce an upward movement of the hollow mandrel assembly 40 and thus Bring the O-rings 46 provided in the mandrel head portion 41 into sealing engagement with the seal bore 33e defined by the seal compression sub 33, as shown in FIGS. 2B and 2C. Additionally, the end face 41e of the head portion 41 of the hollow mandrel assembly 40 will engage the downwardly facing abutment surface 33d provided on the seal compression sub 33 and force the sub 33 upwardly, thus compressing the annular elastomeric seal 26 into intimate sealing engagement with the adjacent seal bore surface 2d of the special nipple 2. It is therefore apparent that all fluid flow through the well conduit 1 in interrupted through the inter-engagement of the O-ring seals 46 with the seal bore surface 33e, thus preventing any fluid flow passing through the peripherally spaced flow ports 32d from entering the interior bore of the inserted assembly 10, while the compression and outward displacement of the annular elastomeric seal 26 prevents any fluid passage along the exterior of the inserted assemblage 10. It is therefore apparent that the well condition sensing devices 50 and the flow control valving unit are concurrently run into the well in a single trip on an electric wire line. Furthermore, the valve elements may be repeatedly actuated to a closed position by applying an upward tensile force on the electric wire line sufficient to cause upward movement of the hollow mandrel assembly 40 into the valve closing position shown in FIGS. 2B and 2C. To return the valving elements to their open flow position, as illustrated in FIGS. 1B and 1C, it is only necessary to relax the tension on the electric wire line 3 and then apply sufficient fluid pressure down the well bore, such as nitrogen gas, to equalize the formulation fluid pressure operating on the hollow mandrel assemblage 40 to hold it in an upward position. Such equalization of fluid pressure is conveniently achieved through the provision of the plurality of peripherally spaced ports 34 provided in the upper portion of the seal compression sub 33, between valve seat 33e and outer seal 26. Each port 34 has an enlarged counter bore 34a and a conventional check valve 34 (shown only schematically in the drawings) mounted in each counter bore 34a which permits only outward flow through ports 34. Once the pressure differential across the hollow mandrel assembly 40 is removed or substantially reduced, the compressed spring 45, plus the weight of hollow mandrel assembly 40 will effect the return of the hollow mandrel assemblage to the position shown in FIGS. 1B and 1C. At the completion of the testing operations, the aforedescribed mechanism may be conveniently removed from the well conduit. First the electric wire line 3 is sheared at a deliberately weakened zone provided immediately adjacent to the cable anchor 42. A conventional retrieving tool (not shown) having an equalizing prong or other means to actuate the valve 34 is then run into the well on a wire line and engages an upstanding fishing neck portion 22c provided on the top of the anchor sub 22. The retrieving tool incorporates conventional means for effecting the retraction of the locking dogs 23, following which the entire assemblage may be pulled from the well by the retrieving tool. The prong depresses a nub (not shown) on the valve 34 to equalize pressure across the device. Thereafter the retrieving tool engages the portion 22c. It is therefore apparent that a minimum of running operations are required to effect the installation of the combination tool in the well and its subsequent removal. Those skilled in the art will recognize that the sealing arrangement between head portion 41 of the hollow mandrel assemblage 40 and the seal compression sub 33 is only typical of a number of well known sealing arrangements. Thus, the seal compression sub 33 could be provided with an elastomeric sealing material on the downwardly facing surface 33d which is engaged by the top surface 41e of the head portion 41 of the hollow mandrel assemblage 40. The essential feature is that a seal is achieved to interrupt fluid flow from the exterior of the tool into the bore through the cooperation of two annular valving elements, and the electric wire line for operating the valving elements passes through the bore of the two annular valving elements. Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto, since alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention.	A method and apparatus for installing in a well conduit by a single trip on an auxiliary conduit a combination well condition sensing device and flow cut off valving elements. The cooperating valving elements are of annular configuration and the auxiliary conduit passes through the bore of the valving elements and is mechanically connected to one of the valving elements. The entire apparatus may be run into the well conduit in a single trip on the auxiliary conduit and actuated to a flow shut off position by longitudinal manipulation of the apparatus. Pressurization of the upper well conduit and secondary manipulation of the apparatus and the auxiliary conduit permits the return of the valving elements to an open flow position.
You are an expert at summarizing long articles. Proceed to summarize the following text: SUMMARY OF THE INVENTION [0001] The present invention relates to a shape memory actuator device, comprising of a cable, rigid or flexible, having an end connected to a controlled mechanism and a sheath inside which the cable is fitted, in which at least a portion of the cable is made up of a shape memory material, susceptible to undergo a shape change subsequent to its heating up, to operate the controlled mechanism, and in which it is also foreseen an electric supply circuit to feed through the shape memory cable an electric current in order to cause it to heat up. [0002] A shape memory actuator device of a type described above has been proposed by the same applicant in WO03/003137 A1. An improvement of such device has also been the object of the claim of the European patent 03015862.0 always by the same applicant. [0003] With the view of further improving the device previously submitted, the object of the present invention is a shape memory actuator device having all the characteristics which have been stated above and besides characterized in that it is provided with means suitable to detect a position of an end stop of the shape memory cable subsequent to its heating up and to cut off the electric supply to such cable following such detection. [0004] Thanks to such a characteristic, the shape memory cable cannot be subject to excessive unnecessary heating up, after the controlled mechanism has already been brought to the desired operative position. [0005] Preferably, the actuator according to the invention is of the type (known from WO03/003137 A1) in which said sheath is assembled in respect to a fixed support structure in such a way to be free to move longitudinally only in the direction to activate the controlled mechanism, and also in which the said sheath is coupled to the controlled mechanism in such a way to be able to transmit directly to it a movement in the aforesaid operative direction and to be uncoupled instead from the controlled element in respect to a movement in the direction opposite to the operative one, in such a way that said actuator is apt to be utilized either through a manual operation, using the sheath as an element of mechanical transmission, or by exploiting the shape change of the shape memory cable, obtainable through its heating up. [0006] The actuator according to the invention finds several applications, one of which for example is constituted by the control of a door lock of a motor vehicle. In such an application, it is desirable to be able to operate the opening of the lock either electrically, or mechanically. Of course, with the opening of the lock is meant here the operation through which the lock is “unhooked” allowing the opening of the door and not the operation through which the locking block is removed in the closed condition. Thanks to the use of the actuator according to the invention, the unhooking of the lock can be executed either electrically, for example also through a remote control, or mechanically, acting on the door handle of the motor vehicle. A particular advantageous application is that of a lock of a bonnet or of a back hatch door of the motor vehicle, where it must be possible to operate either electrically or mechanically from the inside of the motor vehicle, in case that a person has remained inadvertently closed inside the motor vehicle. Thanks to the additional characteristics foreseen according to the invention, the shape memory cable being part of the actuator is protected from the risk of damaging by overheating. [0007] Preferably, the said means apt to detect a position of the end stop of the shape memory cable are integrated in the actuator. BRIEF DESCRIPTION OFF THE DRAWINGS [0008] Further characteristics and advantages of the invention will result in the description which follows with reference to the enclosed drawings, supplied purely as a non limitative example, in which: [0009] FIG. 1 is a perspective view partially cross sectioned of a form of realization of the actuator device previously proposed by the same applicant, corresponding to FIG. 5 of the international patent claim above identified, [0010] FIG. 2 is a perspective view partially cross sectioned of the shape memory cable being part of the actuator, according to the solution already proposed in the European patent claim also above identified, [0011] FIGS. 3, 4 show a detail of the actuator device according to the present invention in two different operative conditions, [0012] FIGS. 5, 6 are two cross section views of two variations of the actuator according to the invention, and [0013] FIGS. 7, 8 show two cross sections according to the lines VII and VIII of FIGS. 5, 6 . DETAILED DESCRIPTION OF THE INVENTION [0014] With reference to FIG. 1 , an example is here illustrated of an application of the actuator previously proposed to operate the lock of the bonnet or the back hatch door of the motor vehicle. [0015] Regulations are foreseen that will compel the manufacturer to foresee the possibility to operate the lock manually from inside, to allow the opening of the hatch door to a person who might have accidentally been closed inside the motor vehicle. In the illustrated example, the actuator can be operated manually through a ring 100 which is connected through a cable 101 to the sheath 3 of a flexible cable actuator device. On the sheath 3 is secured a bushing 102 intended to come into contact against a fixed stop 103 being part of the structure 104 of the locking device of the hatch door. The cooperating action of the bushing 102 integral with the sheath 3 and of the end stop 103 prevents a movement of the sheath 3 in an opposite direction to the one of activation. Inside the sheath 3 is fitted a flexible cable 2 of memory shape material (let it be clearly understood that it is also possible to realize the device with a rigid cable instead of a flexible one) which is secured at an end 2 a to a cylindrical body 5 which is in turn connected, through an opening 105 made in the wall of the casing of the lock 104 , to the controlled mechanism of the lock (not illustrated). Means of electricity supply (not illustrated) are also foreseen to apply an electric tension to the two opposite ends of the shape memory cable 2 , with the aim to cause it to shorten. When the actuator is operated manually acting on the ring 100 , the mechanical traction is transmitted through the sheath 3 which is shifting towards the right (with reference to FIG. 1 ) causing a distancing of the bushing 102 from the fixed stop 103 . The movement of the sheath 3 causes a corresponding movement of the cylindrical body 5 , since at the extremity of the sheath 3 is fastened a ring 11 which is resting against an extremity surface 5 a of an internal cavity of the cylindrical body 5 . The movement of this last one causes in consequence an activation of the controlled mechanism, which, as already indicated, is connected to the cylindrical body 5 by a connection passing through the opening 105 . [0016] In the case, instead, of electric activation, the sheath 3 stand still, because it cannot move towards the left due to the resting of the bushing 102 against the fixed stop 103 , while the shape memory cable 2 shortens, provoking a sliding of the cylinder 5 over the sheath 3 (by which the ring 11 distances itself from the resting surface 5 a ) and again an activation of the controlled mechanism. [0017] The advantage in using the sheath of the actuator device as an element of mechanical transmission in the case of manual activation consists in the fact that in such a way it is possible to guarantee always the functioning of the device, even in the case of an accidental breakage of the flexible shape memory cable. [0018] It is possible to observe that in the case of the previously proposed solution, illustrated in FIG. 1 , between the cable 2 and the sheath 3 a distancing layer 106 of synthetic material is interposed which is united to the sheath 3 and is integral with it. Such a layer has only a distancing function, so that during the functioning of the device, a relative movement is created of the flexible cable in respect to it. [0019] In the case of the solution, also already proposed, illustrated in FIG. 2 , instead, a structure of a different type is associated to the flexible cable. Also in this case between the flexible cable 2 of the shape memory material and the relative flexible sheath 3 , a distancing layer 106 is foreseen, which in the illustrated case is constituted of a braided wire. [0020] The difference in respect to the solution illustrated in the FIG. 1 lies in the fact that in this case over the cable of shape memory material 2 is moulded a coating layer 110 that adheres to the shape memory cable 2 and is selected in elastomer/silicone or synthetic materials so that it facilitates either the cooling of the cable 2 after the switch off of the current, or the return of the cable 2 in its resting configuration, due to the effect of the elastic return of the coating 110 . [0021] Preferably the coating 110 is moulded on top of the cable 2 through an operation of simultaneous extrusion of the material constituting cable 2 and by the coating 110 . In other words, during the production process, the cable 2 and the relative coating 110 are obtained simultaneously, through a process of co-extrusion, which presents the advantage to obtain the desired structure with a single operation, without the necessity of additional assembly operations. [0022] The coating 110 , which is adherent to the cable 2 , performs the function of a spring distributed longitudinally, which is subjected to compression when the cable 2 shortens following its activation and consequently facilitates the return of the cable to the resting position through its elastic return. [0023] The shape memory cable could be of any configuration. Besides it is possible to co-extrude several shape memory cables inside the same coating. A configuration of the cable as a U is of particular interest, with a forward tract and a return tract and the two extremities of the cable adjacent between them, which amongst other things gives the advantage of an easy electrical connection of the cable to the electricity supply means. [0024] In the FIGS. 3-8 , the common parts to those of FIGS. 1, 2 are indicated by the same reference number. With reference in particular to FIGS. 3, 4 inside the body 5 ( FIG. 1 ) which is connected rigidly to the terminal end 2 a of the shape memory cable 2 , two metallic terminals 301 , 302 are predisposed which are connected respectively to the earth and to the positive pole in the electric supply circuit of the shape memory cable 2 . The two terminals 301 , 302 present two overhanging placed lamellae 301 a, 302 a, electrically deformable by flexing, which are normally in contact between them, assuring the continuity of the electric connection of the shape memory cable 2 to the electric supply means. The base portions of the terminals 301 , 302 are securely fixed inside the body 5 . Furthermore a coil spring 303 is coaxially placed around the cable 2 inside the cavity of the body 5 , between the base part of the terminal 301 and the extremity of the sheath 3 and of the relative support 11 . To such support a pointed appendix 304 is solidly integrated. [0025] FIG. 3 shows the configuration of the device in the resting position. When the actuator is activated through an electric supply to the shape memory cable 2 , the end terminal 2 a of the cable 2 lowers itself (with reference to FIGS. 3, 4 ) in respect to the terminal portion of the sheath 3 until it reaches the position of end stop illustrated in FIG. 4 . In such position the pointed appendix 304 penetrates between the two lamellae 301 a, 302 a of the terminals 301 , 302 opening them wide and separating them one from the other so to disconnect the continuity of the supply circuit of the cable 2 . The electricity supply of the cable is therefore disconnected, protecting such cable from the risk of overheating. In the case for example of the application to the opening of the lock of a bonnet or a back hatch door of a motor vehicle, it so prevents the cable becoming damaged by excessive heat, which becomes totally unnecessary once the opening of the lock has been obtained. Naturally, the activation of the shape memory cable 2 provokes the movement above described against the action of the spring 303 , which provides the return of the device to the rest position when the power supply is disconnected. [0026] FIGS. 5, 7 show the solution already mentioned above where the same cable 2 is sent back at U so to present two branches parallel between them 2 ′, 2 ″ secured to the body 5 corresponding to their two end terminals 2 a, adjacent between them. The whole of the two branches 2 ′, 2 ″ is contained inside the same sheath 3 . [0027] FIGS. 6, 8 show a further variation that always foresees two shape memory wires 2 ′, 2 ″ parallel between them, which in this case however are two wires separated one from the other, contained inside the same sheath 3 and secured at the extremities 2 a to the body 5 (not illustrated). [0028] In both cases shown in FIGS. 5, 7 and 6 , 8 , the disposition of the terminals 301 , 302 and the pointed appendix 304 is analogous to that already described with reference to FIGS. 3, 4 . [0029] Naturally, keeping firm the principle of the invention, the particulars of the construction and the forms of realization could extensively change in regard to what has been described and illustrated only as an example, without leaving from the present invention.	A shape memory actuator device, comprising of a shape memory cable assembled through a sheath and susceptible of being supplied with an electric current to cause it to heat up. The sheath is placed in such a way to allow a manual activation of the controlled mechanism, acting as a transmission element, alternatively to the electric activation through the shape memory cable. Means are foreseen to detect the stop end position of the shape memory cable following its heating up in order to disconnect the electricity supply to such cable and to protect it from the risk of overheating. It is possible to foresee more shape memory cables placed parallel between them.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a hinge for a mobile terminal, such as a mobile telephone, and to a novel type of hinge, which may be used for mobile terminals. [0003] 2. Description of Prior Art [0004] Presently, mobile terminals may be made as two-part terminals where the two parts are able to rotate in relation to each other from an inactive position to an active position. Some of these terminals have a snap opening function whereby the rotation to the active position is automatic upon activation of a button. However, due to the biasing, the active position and the inactive positions are the only positions maintainable. Thus, this brings about a problem when e.g. trying to position the terminal in a manner so that a display or the like may be visible. [0005] It has been found that it is desirable to have, in a mobile terminal, a more freely selectable angle or rotation between such two parts. SUMMARY OF THE INVENTION [0006] Thus, in a first aspect, the invention relates to a mobile terminal having two parts connected to each other by a hinge, the hinge comprising: [0007] a helical spring having a longitudinal axis, the spring comprising one or more wound strands of material, each strand having two ends, [0008] a first hinge part extending into the helical spring, contacting an inner part of the helical spring at a first position or area along the longitudinal axis, and being connected to or attached to a first part of the two parts, and [0009] a second hinge part contacting the one or more strands of the helical spring and being connected to or attached to a second part of the two parts, [0010] the spring facilitating that: [0011] rotation of the first hinge part in a first direction around the longitudinal axis and in relation to the second hinge part will provide a first, lower friction between the first hinge part and the helical spring, and [0012] rotation of the first hinge part in a second direction, being opposite to the first direction, around the longitudinal axis and in relation to the second hinge part will provide a second, higher friction between the first hinge part and the helical spring [0013] the terminal further comprising: [0014] release means for increasing a diameter of the helical spring at the first position or area in order to reduce the second, higher friction between the first hinge part and the helical spring during rotation of the first hinge part in the second direction, the second, higher friction being reduced to a third friction, and [0015] biasing means for providing a rotation of the first hinge part in the second direction when the release means are operated, the biasing means providing a force exceeding a force required to overcome the third friction but being lower than a force required to overcome the second friction. [0016] In this context, it should be noted that the hinge may have other, more standard, hinge means, whereby the present helical spring assembly may mostly be used as a rotatable clutch of the hinge. [0017] A standard helical spring is normally made of only a single strand or elongated piece of the material (typically a metal or another stiff material). However, springs are contemplated being formed by a number of strands, the windings of which are positioned, one after the other, along the longitudinal axis of the spring. [0018] Also, the helical spring needs only be formed by part of the strand(s). The ends of the strand(s) need not be part of the helical spring. These ends may be used for different purposes, such as immobilization or actual movement. [0019] The normal manner of providing a wrap spring clutch is to have the two hinged or clutched elements extend into the spring and thereby engage the inner part of the spring. However, it should be noted that the same effect may be obtained by reversing the operation and engaging the spring at an outer side thereof. Thus, in order to loosen the engagement, the spring is then not loosened (diameter increased) but tightened (diameter reduced). [0020] In this context, the first hinge part would normally extend into the spring from one end thereof and engage the inner side of the spring (at least in the clutched operation) along a position and area from that end and a predetermined distance into the spring along the axis. However, the part needs not contact the spring at the end but may do so at any position thereof. [0021] The first hinge part preferably has, at the part extending into the spring, an at least substantially circular cross section corresponding to an inner cross section of the spring. In that manner, contact inside the spring may be a contact along the inner circumference of the spring. [0022] The contact of the second hinge part and the spring may be an attachment or a biasing, depending on which type of movement of the spring the second hinge part is to prevent or brake. [0023] If both the first and second hinge parts extend into the spring, the first and second hinge parts engage or contact the spring at different positions or areas along the longitudinal axis of the spring. The first hinge part extends into the spring, but the second one may engage an outer surface thereof, an inner surface thereof, or actually a part of the strand(s) not being part of the actual helical shape of the spring. This will become clearer below. [0024] It is clear that friction is a manner of keeping two elements in a predetermined position until a force is experienced large enough to overcome the friction, where after rotation is obtained. [0025] The operation and direction of the biasing force results in that the biasing means is not able to actually rotate the parts until the release means of the hinge is operated, whereby the second friction is reduced to the third friction. It is seen that the release thus provides a snap/automatic movement of the pertaining parts of the terminal. However, the hinge provides, at the same time, a freely selected rotational position of the two parts in that the biasing or snap action is only provided when the release means is operated. [0026] In one embodiment, the spring comprises a non-helical part at an end of each of the one or more strands, and the second hinge part contacts only the non-helical part. Thus, the second hinge part does not actually extend into the spring and/or engage the inner part thereof. In this embodiment, the contact between the second hinge part and the non-helical part of the spring may be an attachment. Preferably, the first hinge member contacts at least substantially a full inner surface of the spring and/or extends a full length of the helical part of the spring (in the direction of the axis). [0027] In another embodiment, one end of each of the strand(s) of the spring is fixed in relation to the second hinge part and the release means is adapted to displace the other end(s) of the strand(s) from a first position to a second position. In this embodiment, the release means are preferably adapted to not be rotated in relation to the second hinge part in order to facilitate the design of the release mechanism. [0028] It may be desired to actually ensure that an accidental operation of the release means does not bring about rotation. Thus, the terminal could further comprise locking means for maintaining the parts in a predetermined rotational angle even when the release means are operated. [0029] One manner of obtaining this displacement is one wherein the release means comprises, for each hinge, a wedge-shaped element adapted to be translated and thereby displace the end(s). [0030] Another manner is one wherein the release means comprises, for each hinge, a flexible element engaging the end(s), the end(s) being adapted to bias the flexible element into a first, deformed state when in the first position, and the release means comprising means for bringing the flexible element into a first, regular state and thereby bringing the end(s) into the second position. This may be obtained when the flexible element is hollow and wherein the means for bringing comprise a means adapted to be translated into the hollowness of the flexible element. These bringing means may be translatable into and out of the flexible element and may be biased in a direction out of the hollowness so as to ensure that the end returns to the first position and that engagement is obtained between the first hinge part and the spring. [0031] A second aspect of the invention relates to a hinge or a clutch for facilitating rotational movement of a first hinge part in relation to a second hinge part and around a rotational axis of the hinge, the hinge comprising: [0032] a helical spring having a longitudinal axis along the rotational axis, the spring comprising one or more wound strands of material, each strand having two ends and a part extending outside the helical spring, [0033] the first hinge part extending into the helical spring, contacting an inner part of the helical spring at a first position or area along the longitudinal axis, and [0034] a second hinge part being attached only to the extending parts of each of the one or more strands of the helical spring, [0035] the spring facilitating that: [0036] rotation of the first hinge part in a first direction around the longitudinal axis and in relation to the second hinge part will provide a first, lower friction between the first hinge part and the helical spring, and [0037] rotation of the first hinge part in a second direction, being opposite to the first direction, around the longitudinal axis and in relation to the second hinge part will provide a second, higher friction between the first hinge part and the helical spring. [0038] Thus, the second hinge part does not contact the spring inside the helical part thereof—or at least does not contact the spring in the helical part. Contacting the spring at an end of the strands, such as ends not forming part of the helical spring but extend away there from, may render the mass production of this hinge or clutch more controllable. [0039] Naturally, this hinge preferably comprises release means for increasing a diameter of the helical spring at the first position or area in order to reduce the second, higher friction between the first hinge part and the helical spring during rotation of the first hinge part in the second direction, the second, higher friction being reduced to a third friction [0040] Also, the hinge preferably further comprises biasing means for providing a rotation of the first hinge part in the second direction when the release means are operated, the biasing means providing a force exceeding a force required to overcome the third friction but being lower than a force required to overcome the second friction. In this situation, both the automatic rotation and the freely selectable position are possible. [0041] In one embodiment, again, the release means comprises, for each hinge, a wedge-shaped element adapted to be translated and displace the end(s). [0042] In another embodiment, the release means comprises, for each hinge, a flexible element engaging the end(s), the end(s) being adapted to bias the flexible element into a first, deformed state when in the first position, and the release means comprising means for bringing the flexible element into a first, regular state and thereby bringing the end(s) into the second position. This flexible element could be hollow and the means for bringing could then comprise a means adapted to be translated into the hollowness of the flexible element. Also, then the bringing means are preferably adapted to be translated into and out of the flexible element and are biased in a direction out of the hollowness. [0043] A third aspect of the invention relates to a method of operating a mobile terminal according the first aspect of the invention, the method comprising: [0044] operating the release means so as to have the biasing means rotate the first hinge part from an initial position in the second direction in relation to the second hinge means through a first angle to a second position, [0045] disengaging the release means, [0046] rotating the first hinge part in the second direction and through a second angle being smaller than the first angle to a third position, and [0047] allowing the hinge to maintain the first hinge part in the third position. [0048] Thus, using this method, the automatic opening and the then freely selectable position is obtained. BRIEF DESCRIPTION OF THE DRAWING [0049] The invention will be explained more fully below, by way of example, in connection with preferred embodiments and with reference to the drawing, in which: [0050] [0050]FIG. 1 illustrates the parts of a clutch/hinge, [0051] [0051]FIG. 2 illustrates the parts of FIG. 1 assembled to the hinge, [0052] [0052]FIG. 3 illustrates a different embodiment of a hinge, [0053] [0053]FIG. 4 is a cut-through view of yet an embodiment of a hinge, [0054] [0054]FIG. 5, is a cut-through view of the hinge of FIG. 4 now also having a biasing spring, [0055] [0055]FIG. 6 illustrates one manner of loosening the helical spring, [0056] [0056]FIG. 7 illustrates another embodiment of a manner of loosening the helical spring, [0057] [0057]FIG. 8 illustrates a system having two parts, a hinge as seen in FIG. 5 and a spring loosening means, [0058] [0058]FIG. 9 illustrates three different positions or angles between a mobile telephone body and a movable part thereof, and [0059] [0059]FIG. 10 illustrates an embodiment different from that of FIG. 9. DETAILED DESCRIPTION OF THE INVENTION [0060] [0060]FIG. 1 illustrates the basic elements of a known wrap-spring clutch/hinge. This hinge 10 comprises two rod members 12 and 14 and a helical spring 16 having an internal surface 17 and two strand ends 18 and 20 . The diameters of the rod members 12 and 14 are larger than the internal diameter of the spring 16 . [0061] This hinge is assembled in FIG. 2 where the rod members touch inside the spring 16 . It is clear that if the end 18 is kept fixed in relation to the rod member 12 , rotation of the rod member 14 in the direction of the arrow will tighten the spring 16 and thus lock the two rod members 12 and 14 to each other so as to obtain maximum torque. In that manner, torsion or rotational energy is transferred from rod member 14 to rod member 12 . On the other hand, if the rod member 14 was rotated in the other direction (opposite to the arrow), this movement will only loosen the spring 16 , whereby almost no torque is transferred. [0062] Also illustrated in FIG. 2 is a wedge 15 which may be used for moving the end 20 of the spring 16 . If the wedge is moved so as to lift (on the figure) the end 20 , the spring 16 will be “loosened” which means that the internal diameter thereof will increase so that the rod member 14 may now be moved in the direction of the fat arrow without tightening the spring 16 and transferring torque to the rod member 12 . [0063] In that manner, rotation of the member 14 in the direction of the fat arrow, around the longitudinal axis A, without operating the release wedge 15 , a high friction is obtained due to the fact that the spring 16 will tighten. Rotation in the opposite direction of the member 14 will, on the other hand, incur a much lower friction due to the spring 16 loosening. Also, when operating the wedge 15 , a third, low friction is experienced when rotating the member 14 in the direction of the fat arrow. [0064] In FIG. 3, a different embodiment is illustrated which also has the rod member 14 and the spring 16 with the ends 18 and 20 . However, the rod member 12 has been removed, and instead the element hitherto connected to the rod member 12 is attached to the end 18 . As described above, this embodiment has certain advantages to the embodiment where the rod members abut in the spring 16 . Preferably, the rod 14 now extends throughout the whole of the helical spring 16 . [0065] [0065]FIG. 4 illustrates another embodiment of a hinge having the same function. This hinge also has a first rod member 12 , the second rod member 14 —now in the form of a tubular element extending over part of the rod member 12 . The spring 16 has the “unlocking end” 20 and the end 18 , which is now fixed to a fixed element. [0066] In FIG. 5, the hinge of FIG. 4 has been added elements 30 (fixed to the rod member 12 and in which the end 18 is fixed) and 32 (fixed to rod member 14 ) as well as a locking element 42 preventing the spring 16 from moving into a space between the rods 12 and 14 and creating backlash etc. in the system. It is seen that instead of immobilizing the end 18 , the element 30 may be immobilized. Also, a biasing spring 44 is added having one end attached to the element 32 and the other (not illustrated) fixed to the rod member 12 . Thus, it is clear that the element 32 and rod member 14 may be rotated over the rod member 12 , this movement being biased by the biasing spring 44 . [0067] In this respect, it is preferred that the fixed end 18 and the wedge 15 (see also FIGS. 6 and 7) exist in the same system—meaning that these elements are not rotatable (but may be translatable) in relation to the rod member 12 or element 30 . This will become clear from FIG. 8. [0068] A number of choices exist when assembling the present hinge. Either the spring 16 is slightly opened before introducing the rods 12 and 14 (when the outer diameter of the rods is larger than the inner diameter of the spring) so as to obtain an engagement or friction there between in the un-operated situation (when the outer diameter of the rods is smaller than the inner diameter of the spring), so that operation may be a loosening of the spring 16 . Alternatively, it may be desired to actually bias the end 20 in the un-operated situation, so that operation may be a tightening of the spring 16 . In either way, it may be desired to bias the end 20 in the “tightening” direction in the un-operated situation. [0069] [0069]FIGS. 6 and 7 illustrate different manners of actually loosening the spring 16 . In FIG. 6, the wedge 15 is illustrated together with two different positions of the end 20 of the spring 16 . Depending on the distance between the wedge 15 and the helical part of the spring 16 , this movement of the end 20 will provide more or less loosening of the spring 16 . [0070] In FIG. 6, the wedge 15 is supplemented by another element 15 ′ forming, together with the wedge 15 a track in which the end 20 travels. This track may be used for actually biasing the end 20 in the tightening direction. This operation is seen as the un-biased position of the end 20 is illustrated by a dotted end 20 ′. Thus, moving the end 20 upwards will loosen the spring, and in the un-operated position, the end 20 is that depicted at the lower position, which is lower than the unbiased position 20 ′. [0071] Another manner is seen in FIG. 7, where the end 20 rests against a flexible element 24 inside which an elongated, stiff element 26 may slide. It is seen that the end 20 , in fact, is biased against the element 24 in such a manner that when the element 26 is retracted, the end 20 will deform the element 24 and thereby tighten the spring 16 . [0072] The element 26 is biased away from and out of the element 24 by a biasing spring 27 , and the elements 26 , 24 and 20 are controlled by holding means 22 . [0073] Returning to FIG. 2, it is clear that loosening of the spring 16 may be performed by moving the spring end 20 in a number of ways, such as in the direction of the fat arrow or in a direction along the end 20 toward the spring 16 . [0074] [0074]FIG. 8 illustrates a two-part system having a first part 30 connected via a hinge 50 to a second part 32 . The reference numerals from FIG. 5 have been omitted in order to retain the clarity of the figure. [0075] The actual “direction” of the hinge (that is, the high friction and low friction rotation directions and the directions of the biasing springs) will depend on the actual embodiment. Two embodiments are described in relation to FIGS. 9 and 10. [0076] The part 30 of the system of FIG. 8 has a spring loosening mechanism having a push button 29 connected to a loosening mechanism 36 , such as the wedge 15 , and being biased by a biasing spring 38 engaging a fixed element 40 in the part 30 . [0077] The first part 30 is further rotationally attached to the second part 32 by an element 42 . This is only to stabilize the rotation of the parts. [0078] In FIG. 9, the mobile telephone 28 has the first and second parts 30 and 32 as well as a hinge or clutch illustrated at 33 , a release mechanism 34 for the hinge 33 . [0079] [0079]FIG. 9 illustrates three different angles between the first part 30 and the second part 32 and therefore a specific use of the mobile telephone 28 . [0080] In normal non-operative use, the mobile telephone 28 will be stored as illustrated in the left-most drawing where the first and second parts 30 and 32 are adjacent to each other. In the present embodiment, the second part 32 has a microphone 41 protected in the position in the left-most illustration. The telephone 28 also has a speaker 39 in the first part 30 . [0081] The hinge 33 is provided in the telephone 28 so that the rod member 14 is attached to the second part 32 and so that the rod member 12 and/or the end 18 is attached to the first part 30 . Also, a release mechanism as that illustrated by the wedge 15 is operatively connected to the button 34 . The spring 16 is directed so that the rotation in the direction of the fat arrow (see FIGS. 2 or 3 ) will take place when rotating the second part 32 as illustrated by the fat arrow in the middle illustration of FIG. 9. [0082] In order to operate the telephone 28 , such as when wishing to make a telephone call, the second part 32 is rotated as illustrated by the fat arrow in the middle illustration. In this manner, the microphone becomes accessible. This activation is obtained by releasing the release mechanism 34 , which loosens the spring 16 and allows the biasing means to overcome the third friction and rotate the second part 32 to e.g. a stopping position as that illustrated in the middle illustration. This position may be pre-defined as that providing the optimal position for use when making a telephone call. This position may also be one where the second part 32 is rotated further in the direction of the fat arrow. [0083] Having obtained that position of the second part 32 , the release button 34 is disengaged. [0084] Having e.g. made the telephone call, it may be desired to have a different angle on the second part 32 such as in order for the telephone 28 to be able to stand up and present a display 31 thereof to the user. Thus, the second part 32 may be rotated in a direction opposite to that illustrated by the fat arrow. Due to the friction of the hinge 33 —as well as the operation of the biasing means, the second part 32 will be substantially fixed and will be able to e.g. hold the telephone at the desired angle or in the desired position. [0085] The telephone 28 may also have a locking means 37 for maintaining the second part 32 in the closed position even if the release button 34 is operated. [0086] Naturally, the hinge may be reversed to that a snap closing is achieved by operating the button 34 . Thus, the parts are rotated by hand (in the low friction direction of the hinge), and are maintained in that angular position until the button is operated, where after the biasing spring will close the parts again. [0087] Finally, in FIG. 10, a further embodiment is seen at an angle from the back (above) and directly from the front (below). This embodiment 51 may also be a telephone or a palm computer having two parts 52 and 54 interconnected by a hinge (not illustrated) and having a release button 56 to be used as described above. [0088] Thus, operation may be as described above: operation of the release button 56 may make the biasing means open the telephone/computer 51 for operation. Releasing the release button will make further rotation in the opening direction (the fat arrow) difficult (due to the high friction), but rotation in the opposite direction (the closing direction) will be easy. [0089] Again, any desired angle between the parts may be obtained at the same time as a snap opening (the operation of the biasing means) may be obtained. [0090] The present embodiments have centred on mobile telephones. However, the same functionality may be obtained in any type of element where a combination of an automatic opening of a device is desired combined with a subsequent, freely selected positioning of the elements. This may be in hand-held or palm-size electronic systems, portable computers or toys of any type.	A mobile terminal, such as a mobile telephone, has a hinge with a helical spring and which provides both snap opening or automatic opening upon activation of a release means as well as a freely selectable angular position between the rotating parts of the terminal. Also, a new type of spring hinges or clutches are described for use in e.g. this type of terminal.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION [0001] The present invention relates to concrete structures. More specifically, the invention relates to slip formed concrete structures, particularly structures made of high strength concrete. BACKGROUND OF THE INVENTION AND PRIOR ART [0002] Currently, many concrete structures, such as concrete shafts, are typically formed by slip forming, alternatively termed slip casting. Compared to forming with fixed forms, slip forming is very favorable, particularly from an economical point of view, since the extent of the work is greatly reduced. However, the surface of a slip formed concrete structure includes irregularities, particularly when high strength, abrasion resistant concrete qualities are used. The result is reduced erosion and abrasion resistance, reduced service life and reduced surface quality, compared to a structure having a smooth surface, all of which has technical and economical consequences. Repair of irregularities or eroded or abraded surface is often very expensive and the quality is still reduced. Forming with fixed forms for all or a part of a concrete structure is often very expensive. [0003] Structures used in the sea in areas infested by drifting surface ice have so far not been protected in the zone abraded by ice by a slip formed concrete abrasion allowance, but with a protective steel structure, due to the above mentioned technical problems. For concrete structures such steel protection is very expensive, requiring extensive scaffolding and additional work at high elevation, and may not be a good technical solution since the integrity has been questionable. Protection using concrete has so far not been possible for the desired reliable, long-lasting, affordable and simple solutions sought for by the industry. [0004] The objective of the invention is to provide a concrete structure and a method of building said structure, providing improvements with respect to the above mentioned problems and disadvantages. SUMMARY OF THE INVENTION [0005] The invention provides a concrete structure, distinctive in that at least a part of the structure has been formed by slip forming with panels inside the slip form, the panels facing the slip form. [0006] Preferably the concrete structure is for use offshore in ice-infested areas, the structure has an increased thickness as an abrasion allowance in a zone abraded by ice drifting on the sea, and the abrasion allowance has been formed by slip forming with panels inside the slip form, the panels facing the slip form. [0007] The invention also provides a method of building a concrete structure, distinctive in that at least a part of the structure is formed by slip forming with panels inside the slip form, the panels facing the slip form. In one embodiment the method is for building a concrete structure for use offshore in ice-infested areas, the structure has an increased thickness as an abrasion allowance in a zone abraded by ice drifting on the sea, the abrasion allowance is formed by slip forming with panels inside the slip form, the panels facing the slip form. [0008] The invention also provides use of panels inside a slip form, the panels facing the slip form, for building a slip formed concrete structure or a part thereof. [0009] The structure, method and use of the invention surprisingly result in a slip formed concrete structure or -part having smooth, plane and hard surface without irregularities such as small cracks, crazes or voids, which has been impossible so far in full scale production, particularly when using hard high strength, abrasion resistant air-rich concrete qualities. Without wishing to be bound by theory, it is assumed that the present invention eliminates or reduces irregularities, particularly lifting crazes or—cracks, in the surface of the ice abrasion allowance as the slip form is lifted upwards, and that such irregularities previously have been the main reason for reduced service life and high abrasion rate. The technical effect can be beneficial for any concrete structure, particularly for high strength quality concrete structures exposed for erosion or abrasion or wear for any reason, for any structures for which reduced drag or friction can be beneficial, and structures for which subsequent treatment can be facilitated. Deterioration, wear, ageing, ingress of salts and chemicals all take place in principle form the surface and inwards, for which reason the structure, the method and use according to the invention can be advantageous since better resistance is provided. Testing so far has confirmed the beneficial technical effect; however, it may take many years of service and testing in order to quantify the technical effect in all of the different aspects thereof. [0010] The term panel means in this context any in substance two dimensional structure useful for the intended purpose. Examples are plates of any feasible material such as metal, polymer material, composite material, concrete and ceramic material. Panels also include any grid, grating, mesh or honeycomb-like plate-like structures. The panels are preferably having a shape adapted for the site it is used, such as the curvature of a platform shaft with round cross section shape. The panels are arranged on the outer side of the abrasion allowance, or for fixed panels as a part of the abrasion allowance, and for all embodiments of the invention the panels are arranged nearest to the slip form, i.e. facing the slip form. [0011] The panels are left in the structure after the slip forming or the panels are removed from the structure after the slip forming. A smooth inner surface is preferred for panels that are removed. An irregular inner surface, such as for feasible grid, grating, mesh or honeycomb-like plate-like structures, is preferred for panels that are left as part of the structure. [0012] The abrasion allowance is formed by concrete, preferably without steel armour reinforcement except of possible reinforcing fibres that optionally may be steel fibres. Any steel reinforcement armouring of the abrasion allowance is preferably without electrical or mechanical contact with the main steel reinforcement armouring. [0013] The length of increased thickness, that is the elevation range of the ice abrasion allowance, preferably encompass the range abraded by drifting ice, which is from the lowest ice draught level at lowest water tide level to the highest expected ice top at the highest water tide level for a gravity base structure. For a floating concrete structure, the tidal range is replaced by the ballast range for the specification of required elevation range having abrasion allowance. [0014] The transition from the ordinary structure to the structure of increased thickness is preferably gradual and preferably formed by an insert form onto which the panels are arranged. Preferably both the panels and the insert form have means for being arranged or connected together, such as by a wedge system, bolts or male-female means. FIGURES [0015] The invention is illustrated with figures, of which: [0016] FIGS. 1 to 5 illustrate sections through a structure according to the invention having an abrasion allowance. DETAILED DESCRIPTION [0017] Reference is made to FIG. 1 , illustrating a section through a wall of a gravity base shaft structure 1 that is slip formed and which shall be provided with an abrasion allowance according to the invention. A slip form yoke 2 and working platforms 3 are lifted upwards concurrently as the structure is slip formed upwards, in a conventional way. [0018] In FIG. 2 , a bolted support 4 and an insert form 5 have been arranged on the outer wall of the structure. In FIG. 3 the first panel 6 has been arranged on the insert form 5 . The volume inside the panel is filled with concrete of a feasible quality for abrasion resistance and behaviour in the forming operation, which quality may be determined by testing. The armouring is not illustrated. Preferably the steel armouring is not extended into the abrasion allowance, but the abrasion allowance may preferably comprise reinforcing fibres such as steel fibres, carbon fibres, boron fibres or other fibres or ceramics or other material for increased abrasion resistance and/or strength. The main structure armouring will thereby not be exposed as the erosion allowance is eroded. [0019] FIGS. 4 and 5 illustrate how the structure is slip casted further, arranging panels successively upwards in order to cover the structure with abrasion allowance over the intended distance or elevation range. The figures also illustrate how the abrasion allowance is terminated at the upper end in a corresponding way as it was started in the lower end, i.e with an insert form and a bolted support. The supports, insert forms and panels are preferably provided with means for being connected together, preferably in a releasable way. During slip forming the slip form slip or slide on the panels, not on the concrete of the abrasion allowance. Accordingly, the concrete of the abrasion allowance is not subjected to shear forces by the slip form. [0020] Preferably the panels, any insert forms and any bolted supports are all removed after the forming operation, leaving a smooth, plane, hard and abrasion resistant regular surface of the abrasion allowance on the structure. Extensive testing has revealed that a concrete quality such as B70 (CEN: C70/85, ref. ISO 19906) is feasible for abrasion allowance. Testing and modelling has revealed that an abrasion allowance thickness of 105-122 mm, over an elevation range of typical 6.6 m encompassing the ice drift abraded zone, for a service life of 40 years on shafts of a gravity base structure in ice infested areas, is convenient. [0021] Testing has revealed that the contents of small cracks or crevices on a concrete surface is dramatically reduced, and the surface become far smoother, with far less irregularities, by slip forming with panels with smooth panel inner surface and removing said panels after forming, according to a preferred embodiment of the invention. The result is inter alia an improved ice abrasion resistance, a reduction in ice formation on the structure per se, increased resistance to repeated cycles of freezing and melting, reduced friction and prolonged service life of the structure.	The invention provides a concrete structure of which at least a part has been formed by slip forming with panels inside the slip form, the panels facing the slip form.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND 1. Field of Invention This invention relates to strengthening the reinforced concrete elements to increases the elements static and dynamic load capacities, and its ductility without significantly increasing the dimensions or weights of these elements, or even harming the concrete section. The invention also includes the apparatus used to apply the required confining pressure. BACKGROUND 2. Description of Prior Art Various techniques are available for strengthening the structural elements whether by making steel or concrete jacketing or in the case of columns by encompassing the existing reinforced concrete section with masonry blocks or strengthening it by either carbon or glass fiber reinforced plastic reinforcement. Through surveying these techniques, some undesirable effects have been found. Summary of these techniques with its disadvantages are presented herein: 1) Concrete Jacketing Concrete jacketing has been widely used in repairing, strengthening, and improving the ductility capacity of damaged and existing reinforced concrete columns. But this technique increases dimensions of the structural element to an undesirable extent. The extra weight resulting from the concrete jacketing may lead to problems in foundations and the underlying soils. In addition, concrete jacketing is not suitable for strengthening in high rise buildings. 2) Steel Jacketing Circular and rectangular steel jacketing are usually used to increase the flexural strength, ductility, and shear capacity of a part in the column. However, this technique mainly provides some local strength capacity increase. It also needs special equipment, besides assembling the steel jacket without post-tensioning it on the reinforced concrete member. Therefore, the clearance between the steel jacket and the reinforced concrete element permits internal strains to take place in the original reinforced concrete section. 3) Masonry Block Jacketing Similar to the concrete jacketing method, a masonry block jacket can be used for repairing and strengthening of existing and damaged columns. The undesirable effects are mainly the increase in dimensions and the additional over loads added to the existing reinforced concrete columns. Besides, this technique is only used in low to medium rise reinforced concrete buildings. 4) Partial Masonry Infill This technique have been used for increasing the stiffness and strength of structures to control story displacements from high wind loads and other natural forces including seismic loads. An architectural disadvantage of using an infill wall retrofit for an existing building is the loss of space and access near the wall, along with adding more loads to the reinforced concrete buildings. 5) Strengthening the Reinforced Concrete Elements Using Either Carbon or Glass Fiber Reinforced Plastic Reinforcement This technique has been used for increasing the stiffness and strength of structural elements like columns, beams, and slabs. The main disadvantage of this technique arises when the strengthened element is subjected to a high temperature at which the strengthening material and epoxy used to bond them lose a great part of their strength. One more disadvantage is the brittle behavior of either carbon or glass fiber reinforced plastic materials, which decreases the ductility of the strengthened reinforced concrete element. At high loads, just before failure, the concrete cover is spilled away with these strengthening materials resulting in a sudden failure in the element. Al-Tuhami and Sakr 1998, suggested an idea to strengthen the reinforced concrete columns. Their idea hypothesizes include making grooves in the original reinforced concrete cover to embed longitudinal bars with Epoxy bond materials between new steel bars and concrete. Then attach pre-stressed spiral or tied stirrups around the column. Finally adding cement mortar to cover the new bars and stirrups. The disadvantages of this idea are the harming of the original reinforced concrete section that arises from making grooves in the concrete cover which can lead to compression failure of the column. In addition the authors did not define how they can attach the pre-stressed spiral or tied stirrups to the concrete section. U.S. patent application Ser. No. 07/646,288 to Fyfe (1991) disclose a limited method to improve the strength of a concrete column, supporting an overhead load and having a base end resting on a surface, using stretchable fibers. The fibers overwrapped about the surface of the column. Then applying a coat of hardenable material over the layer of the fibers. Afterwards a quantity of a hardenable liquid is injected under the layer of the fibers and over the surface of the work area to cause the fibers to undergo more stretching. The main disadvantage arises when the strengthened element is subjected to a high temperature at which the strengthening material and epoxy used to bond them lose a great part of their strength. In addition, this technique is limited to certain column configurations. U.S. patent application Ser. No. 07/036,101 to Creedon (1988) shows a complex method for forming prestressed concrete members using casing disposed around the outside surface of the concrete member and is spaced therefrom so that a cavity is formed between the casing and the outside surface of the concrete member. Then a pressurized medium is injected into the cavity between the casing and the concrete member with predetermined pressure. It can be seen that, this technique needs complex apparatus, beside the difficulty of using this method to strengthen the existing concrete members especially for non-circular shaped cross-sections. OBJECTS AND ADVANTAGES Accordingly, several objects and advantages of my strengthening technique are: 1. It can avoids large dimensions of the strengthened elements compared with other techniques like reinforced concrete and masonry block jackets, which saves more space. 2. The increase of column weight in the present method is so small compared with weights added in case of using concrete or masonry jackets. 3. The method provide increases the static load capacity for existing reinforced concrete elements which is the aim of the most available strengthening techniques. 4. One important object of the present technique is to increase the seismic durability of the reinforced concrete elements especially columns, i.e. the strength of column against long term shaking will increased which cannot be achieved using either carbon or glass fiber reinforced plastic reinforcement methods during strong shaking. 5. It provides a very simple strengthening process and can be carried out so quickly. 6. Another object of the present method is to reduce the strengthening and repairing costs. 7. The present method can solve the problems of discontinuities in connections resulting from concrete, masonry block jacketing, and partial masonry infill techniques. 8—By the invention, the achieved strength of the reinforced concrete strengthened element is attained instantly and does not require the setting time needed in case of reinforced concrete jacket. Further objects and advantages of my invention will become apparent from a consideration of the drawings and ensuing description. DRAWING FIGURES FIG. 1 Strengthening Stages of a Reinforced Concrete Column Using Pressure Casing 1 . FIG. 2A to 2 C Definition of element free length. FIG. 3 typical isometric view of one edge in the pressure casing 1 . FIG. 4 An elevation and a section of a column after applying confining pressure and adding the splices using the pressure casing 1 . FIG. 5 Direction of tying and the tensile force in the threaded bar. FIG. 6 An elevation and a section of a column after removing the pressure casing. FIG. 7 An elevation and a section of a column while a wire mesh wrapped around it. FIG. 8 An elevation and a section of a column after the strengthening process has completely finished by adding the plaster. FIG. 9 An elevation, plan and a side view of a pressure ca. FIG. 10 An elevation and a section of a column during the process of applying confining pressure using the pressure casing 2 . REFERENCE NUMERALS IN DRAWINGS 11 . 1 four angles 11 . 2 the element to be strengthened 12 . 1 the pressure casing 1 13 . 1 nuts 13 . 2 threaded bars 14 . 1 splices 14 . 2 welding 16 . 1 wire mesh 17 . 1 plaster 2 . 1 free length of the element 3 . 1 main angle of the pressure casing 1 3 . 2 piece of angle 3 . 3 piece of plate 3 . 4 holes 8 . 1 plates 9 . 2 a thin plate DESCRIPTION OF THE PREFERRED EMBODIMENT Typical strengthening stages using pressure casing 1 are illustrated in FIG. 1. A stage 11 of the strengthening process is to erect four side angles 11 . 1 , which are cut and placed, on the corners of the element to be strengthened 11 . 2 . Stage 12 in FIG. 1 shows an elevation and a cross-section after placing the pressure casing 12 . 1 over the four side angles 11 . 1 . The threaded bars 13 . 2 are then inserted in their positions and tightened with nuts 13 . 1 as illustrated in stage 13 . In stage 14 FIG. 1, splices 14 . 1 are carefully cut and welded between the four side angles 11 . 1 . Therefore the pressure casing 12 . 1 is untied and removed as shown in stage 15 . Then the strengthened element 11 . 2 is warped with a wire mesh 16 . 1 as shown in stage 16 of FIG. 1 . Plastering 17 . 1 is made to complete the Strengthening process of the reinforced concrete element. In stage 11 , FIG. 1, the underlain angle 11 . 1 is cut at the beginning of the process with a length equals to the free length of the element. Typical examples of what are mean by free length 2 . 1 are illustrated in FIG. 2A (free length of columns), FIG. 2.B (free length of a suspended semell) and FIG. 2C (free length of a beam). The Pressure Casing 1 The pressure casing 1 consists of four main edge parts. Each part is named a main casing angle 12 . 1 . A typical isometric view of one edge of the main casing angle and its component are illustrated in FIG. 3 . Pieces of angles and plates, with holes in one side are carefully cut and welded on the back of the main angle 3 . 1 to be used in the pressure casing 1 . The main angle 3 . 1 and a piece of angle 3 . 2 are welded in a back to back arrangement. Then a piece of plate 3 . 3 , having the same width as the piece of angle 3 . 2 , is welded on the back of the two angles 3 . 1 and 3 . 2 . It should be noted that the hole centers in the piece of plate 3 . 3 and the piece of angle 3 . 2 should be coincident. The length of the plate piece 3 . 3 is equal to the lengths of the two legs of the main angle 3 . 1 and angle 3 . 2 . The same procedure is repeated along the length of the main angle but in a staggered arrangement, as shown in FIG. 3 . FIG. 4 shows an elevation and a section of a column during the process of applying confining pressure. It shows the pressure casing 1 with its components as described above, the concrete section 11 . 2 of the element to be strengthened, and other four angles 11 . 1 . It should be noted that the angle leg length in the pressure casing 12 . 1 must be smaller than that of the underlain four angles 11 . 1 . Parts of the embodiments are shown in FIGS. 6 and 7. FIG. 6 shows an elevation of a column after the process of applying confining pressure. Pieces of steel plates 14 . 1 are carefully cut and welded between every two angles from the underlain four angles 11 . 1 before the pressure casing being untied. FIG. 7 shows a wrapped wire mat 16 . 1 around a column before the final step in the strengthening process. FIG. 8 shows an elevation and a cross-section of a column after adding the plaster material 17 . 1 to the strengthened column. The Pressure Casing 2 Another configuration of the pressure casing are illustrated in FIGS. 9 and 10. FIG. 9 show one side of the pressure casing two. A number of plates 9 . 1 having two open holes 9 . 2 on each, are welded at equal distances on a long thin plate 9 . 3 , as shown in FIG. 9 . This group of plates constitute only one side of the pressure casing 2 . The pressure casing 2 consists of four sides of such group of plates shown in FIG. 10 . Each two parallel sides are typical. As shown in FIG. 10, an elevation and a section of a column after applying the confining pressure and fixing the splices 14 . 1 between the underlain angles 11 . 1 . Operation The technique is based on applying uniform distributed pressure around and along the length of the element, or the required part of it, to be strengthened. This confining pressure is sustained around the element by one of the following methods: The First Method: The first method can be summarized by the following procedures: 1—Four steel angles with equal lengths are cut with a length equal to the free length of the element to be strengthened. FIGS. 2A to 2 C shows what the free length of the element means in column, semell and beam. 2—A pressure casing, consisting of four other steel angles with pieces of angles and plates is prepared for multiple use. The objective of this pressure casing with threading bars is to add the required pre-determined confining pressure to the concrete element. Preparing the Pressure Casing 1 : Pieces of angles and plates, with holes in one side are carefully cut and welded on the back of the main angle 3 . 1 used in the pressure casing. The main angle 3 . 1 and a piece of angle 3 . 2 are welded in a back to back arrangement. Then a piece of plate 3 . 3 having the same width as the piece of angle 3 . 2 is welded on the back of the two angles 3 . 1 and 3 . 2 . It should be noted that the hole center in the piece of plate 3 . 3 and the piece of angle 3 . 2 are coincident. The length of piece of plate 3 . 3 is equal to the length of webs of the main angle 3 . 1 and angle 3 . 2 web. The same procedure is repeated along the length of the main angle but in a staggered arrangement, as shown in FIG. 3 . The above description forms one edge of the pressure casing 1 . The pressure casing 1 consists of four edges as detailed above and shown in FIG. 3 . 3—The pressure casing is assembled around the reinforced concrete element and the steel angles indicated in step number 1, by using threaded bars and two nuts for each threaded bar. The confining threaded bar and nuts is illustrated in FIG. 5 . This figure also show the direction of tying and the resulting tensile force in the threaded bar. 4—The reinforced concrete element is then compressed with the four angles by turning the nuts inward and tensioning the threaded bars using wrench torque. This procedure is repeated for every threaded bar and by succession around the reinforced concrete element and downward. Adding pressure in the lower part of the column usually results in clearance between the reinforced concrete element and the confining system especially in the upper part. Therefore, another round of applying torque is needed until the required confining pressure is reached. FIG. 4 shows an elevation and a section of a column during the process of applying confining pressure. 5—Pieces of steel plates (splices) 14 . 1 are carefully cut and welded between the underlain four angles, prepared in step number 1, and placed on the corners of the element under the pressure casing. The plate pieces (splices) numbers, thickness, widths, welding areas, and the dimensions of underlain four angles 11 . 1 are chosen according to the required confining stress and consequently the required strength and ductility of the strengthened member. It should be noted that the angle web widths in the pressure casing must be smaller than that of the underlain four angles 11 . 1 to allow for welding the splices with the underlain angles. 6—The pressure casing is then untied to be used in another element. FIG. 6, shows an elevation of strengthened column after removing the pressure casing, adding the required confining stress, and welding the pieces of plates. In FIG. 6, the four angles 11 . 1 which have been prepared in step number 1, splices 14 . 1 which have been welded after the process of pre-stressing, and the original reinforced concrete element 11 . 2 . 7—To prepare the strengthened element for plastering and to cover the steel confining system, a wire mat is wrapped around the element, as shown in FIG. 7 . In FIG. 7, the wire mat is indicated by number 16 . 1 . 8—Finally we add cemenmortawchemical adhesive to cover the steel confining system and be used as plastering, at the same time. FIG. 8 shows an elevation and section of a column after the strengt-hening process has completely finished. The Second Method: This method has the same procedures as indicated in the first method, except for the pressure casing, which has different configurations. The pressure casing 2 is used in this method. The details of pressure casing 2 are described as follows: 1—A number of plates having two open holes 9 . 2 on each shown in FIG. 9, are welded at considerable distances between them, on a long thin plate 9 . 3 . This group of plates and the thin one compose only one side of the pressure casing. A typical side is also prepared to be placed on the parallel side of the strengthened element. 2. Other number of plates are also welded on a thin plate at equal distances between them but shifted to be arranged in staggered manner on the perpendicular direction of the above mentioned sides. 3—The pressure casing 2 consists of four sides. Each two parallel sides are typical, as shown in FIG. 10 . The pressure casing 2 is assembled around the reinforced concrete element by the same procedures presented in method 1. As noted above, the only difference between the two methods is difference in the configuration of the two pressure casing. FIG. 10 shows an elevation and a section of a column during the process of applying confining pressure using pressure casing 2 . The advantages of this method over the previous one are that: The second method is preferred in small-scale elements, like experimental models. The second method also gives more area for welding the pieces of plates with the underlain four angles laying on the corners of the strengthened element, which may be required when high confining stress are needed. One shortcoming of this method compared to the first one is that the achieved confinement stress in the first method are more uniformly distributed along the length of the strengthened element. Summary, Ramifications, and Scope The reader will see that the technique presented in this invention provides a simple and effective method that can be used for strengthening the reinforced concrete columns with the following advantages: 1. The technique is very simple and can be carried out so quickly. 2. It reduces the strengthening and repairing costs. 3. It does not need complex technology to be carried out, therefore this method can be easily used in all countries. 4. Using this method avoids large dimensions of the reinforced concrete jacket, which saves more space. 5. The increase of column weight in the present technique is so small compared with weights added in case of using concrete or masonry jackets. 6. It does not harm the original reinforced concrete element during the strengthening operation. 7. The method increases the static axial load capacity for whole existing reinforced concrete elements or part of it, like columns, suspended semells, and beams. The expected increase in the element strength can be measured as a percentage of the distributed confining stress. 8. This technique increases the seismic durability and ductility of the reinforced concrete elements especially columns, to undergo large inelastic cyclic deformations, i.e. the strength of column against long term shaking is increased. 9. It reduces the transverse strains uniformly along the strengthened element. 10. It can solve the problems of discontinuities in connections resulting from concrete, masonry block jacketing, and partial masonry infill techniques. 11. This method can be used for strengthening the high rise reinforced concrete buildings. 12. By the new method, the possibility of making openings beside the column directly under the slab or the beams becomes easier. 13. The problems of local failure resulting from loading test can be avoided through partially confining the upper and the lower parts of the tested specimen by using the present technique. 14—The achieved strength of the reinforced concrete strengthened element is attained instantly and does not require the setting time needed in the case of reinforced concrete jacket. 15—By using this technique on the original reinforced concrete section to be strengthened together with concrete or masonry jackets when the stiffness of the strengthened element needs to be increased, it protects the core of the new section from internal stresses and strains. Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. For example, the invention can cover the strengthening the suspended semelles, beams, beam-column connections, repairing the reinforced concrete elements, strengthening the stone columns and using the technique with the traditional strengthening methods as follows: The proposed technique can be applied in strengthening the suspended semelles since its section is very similar to that of the column. The only difference between them is the direction of the long side which vertical in columns and horizontal in semelles. By some modifications of the above-mentioned technique, the reinforced concrete beams can be strengthened. The technique can be used successfully in repairing the reinforced concrete elements. In case of the existence of some cracks in the concrete element, the cracks are first injected with epoxy bond materials with a simultaneous pressure on the concrete element by using the above mentioned technique. Afterwards, the steps listed above in method one are followed precisely. In old and archeological building where stone columns are still in use, the method is the most effective strengthening technique. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the embodiment illustrated.	A technique and apparatus for retrofitting the concrete elements using external prestressing is presented. The method is more applicable in columns with rectilinear cross-section. This technique increases the strength and ductility of the reinforced concrete elements without significantly increasing the dimensions or weights of these elements, or even harming the concrete section. The technique is simple, easy to use, and does not need special hardware in rectilinear cross-sections. In addition, the technique reduces the lateral strains, internal cracking, and volume increase when adding more loads on the concrete element. Global external prestressing is provided along the whole length or the required part of the element to be strengthened through a set of elongated members using the special apparatus presented hereinafter.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND AND SUMMARY OF THE PRESENT INVENTION The present invention relates generally to soil stabilizer machines. More particularly, the present invention relates to a soil stabilizer machine with a recycler screen for assuring that the output from the machine is properly sized. Self propelled soil stabilizer machines which employ a horizontal rotor surrounded by a housing for comminuting and/or mixing soil and other material over which the machine passes are known. The soil stabilizer machine have found wide applications for many purposes. The machine may be used to dig up and comminute old asphalt paving which is reapplied to the ground to form a suitable foundation for subsequent operations. Further, the soil stabilizer machine may be used to blend or mix the soil with suitable additives, such as cement to produce "soil cement" or lime, depending upon the desired use of the processed material. However, if the ground or material over which the machine passes is heavily packed or contains relatively large rocks, blades arranged on the horizontal rotor do not sufficiently break up the material within the housing in a single pass. For certain applications of a soil stabilizer machine, it is essential that the ground or material be broken up into a sufficiently small particle size for the intended use of the processed ground. In some prior art soil stabilizer machines the only way to obtain a desired particle size was to pass over the same ground numerous times with the soil stabilizer machine. This procedure is particularly time consuming and still does not ensure that the desired particle size will be obtained. An apparatus has been proposed in an attempt to control the particle size of cultivated soil. A tiltable cutting edge located on a lower surface of a cultivating machine digs up soil and delivers the soil to a chain belt which moves the material in an arcuate path. The chain belt directs material against a grid comprised of a plurality of rods and cross bars which direct material back to a lower portion of the chain belt if the material is to large to pass through the openings in the grid. The motion of the material between the grid and the chain belt causes lumps of earthy material to be broken up into smaller particles that will pass through the openings in the grid. Eventually, the area between the chain belt and the grid becomes filled with large rocks which cannot be broken up and accordingly the machine must be stopped so that the area may be emptied. A device of this general type is disclosed in U.S. Pat. No. 4,005,755 issued Feb. 1, 1977 to Bakke et al. A further earth preparing apparatus for separating rocks from soil includes a rotatable tilling apparatus for digging into the earth in essentially a plurality of furrows. Quantities of earth are thrown backward relative to the direction of motion of the apparatus against a screen. The screen is inclined away from the rotatable tilling apparatus such that small particles of soil pass through the screen while rocks and clumps of earth which are to large to pass through the screen drop into one of the furrows or channels which have been created by the rotary tilling apparatus. These rocks and large clumps of earth are subsequently covered by soil which passes through the screen. In other words, a device of this type merely places a layer of fine soil on top of the rocks and large clumps which were present initially. A device of this general type is disclosed in U.S. Pat. No. 3,563,191 issued Feb. 16, 1971 to Yovanovich. Other soil stabilizing or cultivating apparatus are disclosed in U.S. Pat. Nos. 3,532,169 issued Oct. 6, 1970 to van der Lely; 3,584,406 issued June 15, 1971 to Kershaw; 3,995,570 issued Dec. 7, 1976 to van der Lely; 4,151,883 issued May 1, 1979 to van der Lely et al; and 4,214,633 issued July 29, 1980 to Jackson et al. None of these patents discloses an apparatus for recycling large particles of materials dug up by a soil cultivator or for assuring that a uniform particle size of the output is obtained. Various objects and advantages will be evident to those of ordinary skill from the following description of a preferred embodiment of a soil stabilizer machine according to the present invention. A soil working or stabilizer machine according to the present invention includes a generally cylindrical rotor having a plurality of teeth arranged along the cylindrical surface of the rotor. The rotor is driven by a suitable motor about a horizontal axis for digging and for comminuting or pulverizing soil. A housing surrounds the rotor for confining the soil dug by the rotor for comminution or mixing by the rotor. According to the present invention, a recycler screen is provided behind the rotor with respect to the direction of travel of the soil working machine. The recycler screen selectively permits particles of soil of less than a predetermined size to be dispensed onto the ground behind the rotor and selectively returns particles of soil or rock greater than the predetermined size to the rotor to be further comminuted by the rotor. In the preferred embodiment, the screen is arranged at a rear of the housing generally parallel to the rotor axis such that a lower edge of the screen is arranged closer to the periphery of the rotor than an upper edge of the screen. This arrangement ensures that the particles which do not pass through the screen will be directed back toward the rotor to be broken into smaller particles within the housing. Further, according to the preferred embodiment, the screen is pivotably mounted about an upper edge of the screen for movement between a first position for sizing the particles and a second, storage position. In the storage position, the screen does not interfere with the dispensing of soil onto the ground behind the rotor. The screen preferably comprises a rigid generally rectangular frame having a plurality of horizontal and vertical rod members secured to the frame and woven together to form openings of a predetermined size through which particles of material must pass. A plurality of vertical reinforcing members arranged on a side of the screen remote from the rotor are provided to reinforce the rods of the screen to limit bending of the rods caused by rocks and material hurled at the screen during machine operation. Still further, suitable arrangements for securely fastening the screen in the first and second positions are provided. The present invention provides a simple and effective apparatus for ensuring that the particles dispensed behind the rotor are properly sized for the particular purpose for the processed material. In addition, the present invention provides a screen which can be readily moved to a storage position so that particles of any size may be dispensed behind the rotor. BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the present invention will be described in greater detail with reference to the accompanying drawings, wherein like members bear like reference numerals and wherein: FIG. 1 is a perspective view of a soil stabilizer machine with a recycler screen according to the present invention shown in phantom lines; FIG. 2 is an enlarged side view of a left side portion of the soil stabilizer machine of FIG. 1; FIG. 3 is an enlarged cross-sectional view of a portion of the soil stabilizer machine taken along the line 3--3 of FIG. 4 showing the recycler screen according to the present invention in greater detail; FIG. 4 is a rear view of the portion of the soil stabilizer machine of FIG. 2 with portions cut away; FIG. 5 is a plan view of the recycler screen removed from the soil stabilizer machine; FIG. 6 is a detail view of a portion of the recycler screen taken along the line 6--6 of FIG. 5; FIG. 7 is a detail view of a portion of the soil stabilizer machine taken along the line 7--7 of FIG. 2 to illustrate the fasteners used for holding the recycler screen in an operative position; and FIG. 8 is a detail view of a portion of the soil stabilizer machine taken along the line 8--8 in FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention may be used with a wide variety of soil stabilizer or cultivating machines of various different configurations. One such soil stabilizer machine is disclosed in U.S. Pat. No. 3,795,279 issued May 5, 1974 to Nelson which patent is hereby incorporated by reference. By way of illustration, and not intended to limit the present invention, one soil stabilizer machine with which a recycler screen of the present invention can be used will be described with reference to FIG. 1. The machine includes a main frame or chassis 21 having two preferably rubber tired rear traction wheels 23 and two preferably rubber tired steerable front wheels 25. An internal combustion engine or other suitable power plant 27 and an operator control console 29 are mounted on the chassis 21. A soil stabilizer unit 31 is located at the rear of the chassis 21 and is connected thereto by a draw bar 33. The stabilizer unit 31 includes a horizontally disposed cross tube 35 which is rigidly connected to a pair of spaced apart rearwardly extending lifting arms 37 between which a horizontally disposed rotatable rotor 39 is mounted. The cross tube 35 is rotatably supported on a support 41 which is secured to the chassis 21. With reference to FIG. 2, the rotor 39 includes a shaft 43 upon which a plurality of tine plates 45 (only one of which is shown) are rigidly mounted. Each tine plate 45 is provided with a plurality of replacable tines 47 equiangularly spaced along the outer periphery of the tine plates 45. The rotor 39 is adapted to be rotated, for example, by low speed hydraulic motors 49 rigidly mounted on the lifing arms 37. The motor output shafts are connected directly to the ends of the rotor shaft 43. It will be understood that the rotor 39 may also be driven by electric motors through drive chains or any other drive rotating mechanism. A mixing box or rotor housing 51 is supported on the draw bar 33 and surrounds the rotor 39. The housing 51 is generally frustro-conical in cross-section and may be equipped to receive various additives to be blended or mixed with the comminuted soil. During operation, housing 51 serves to contain the soil or material displaced by the rotor so that the material can be comminuted and/or mixed by the action of the rotor 39. Each side of the housing 51 includes a clearance slot 53 to afford clearance for the rotor 39 to be raised and lowered by, e.g., a pair of hydraulic actuators (not shown) which have one end connected to the chassis 21 and the other end secured to the lifting arms 37 in a conventional manner. The rotor 39 is raised or lowered within the clearance slots 53 to obtain the desired depth of cut of the rotor 39. The housing 51 is also provided with a tailgate 55 which is positionable by an hydraulic cylinder 57 to ensure an even strike off at the desired elevation of the soil processed by the rotor 39. The tailgate 55 is pivotable about suitable hinging arrangements 59 on either side of the tailgate 55. According to the present invention, a recycler screen 61 (shown in phantom lines in FIG. 1) is arranged within a rear portion of the housing 51 behind the rotor 39 in relation to the direction of travel of the stabilizer unit 31. It should be noted that if the soil stabilizer unit 31 is adapted to work soil in either direction of travel, a second recycler screen can be arranged near a forward end of the housing 51. The recycler screen 61 is arranged generally parallel with the rotor shaft 43 at a location such that the tines 47 will clear the recycler screen 61 in any location of the rotor shaft 43 within the clearance slots 53 in the housing 51 (FIG. 2). The screen 61 is arranged with a lower edge of the screen being closer to the periphery of the rotor 39 than an upper edge of the screen 61. By this arrangement, it is assured that large particles of material or rocks which are unable to pass through the screen 61 are deflected back into the path of the rotor 39 to be further comminuted or pulverized within the housing 51. The screen 61 is arranged at an angle such that the plane of the screen is generally tangent to the rotor cutting circle. In other words, the angle of the screen 61 is arranged such that deflected particles will be directed back toward the periphery of the rotor 39 rather than downwardly toward ground immediately behind the rotor periphery. In this way, large deflected particles are carried along by the rotor 39 and comminuted within the housing 51 before being dispensed on the ground behind the rotor 39. Further, since the screen 61 is generally tangent to the cutting circle, large particles do not drop near the lower edge of the screen 61 without being impacted by the rotor 39. With reference to FIG. 5, the screen 61 includes a generally rectangular frame having an upper horizontal member 63, a lower horizontal member 65 and two parallel vertical side members 67. Each of the members comprising the frame are preferably made from elongated sections of angle iron. As best seen in FIG. 4, the screen 61 extends substantially the entire width of the housing 51 so that material dug by the rotor 39 cannot be dispensed behind the rotor 39 without passing through the screen 61. Secured to the side frame members 67 are a plurality of horizontal rod members 69 while a plurality of vertical rod members 71 have ends secured to the upper frame member 63 and the lower frame members 65. The horizontal rod members 69 and the vertical rod members 71 are arranged in a woven pattern to form a plurality of openings of a predetermined size. The woven pattern also helps improve the stability of the entire screen assembly (FIG. 3). The rod members are preferably made of a suitable steel. The ends of the horizontal and vertical rod members are secured to a side of the frame members facing the rotor by any suitable connection, for example, by welding. By securing the rod members to the frame side facing the rotor 39, particles directed at the screen 61 will not tend to break the rod members away from the frame members. A plurality of spaced apart vertical stiffener ribs 73 are preferably provided along respective vertical rod members at evenly spaced intervals. In the illustrated embodiment, the stiffener ribs 73 are provided along approximately every third vertical rod member 71 to further stiffen the screen assembly against impacts from large particles and to further increase the strength of the assembly. The vertical rod members 71 are preferably welded to the corresponding stiffening rib 73 at each point at which the rod members 71 contact the ribs (FIG. 6). With reference to FIG. 5, secured by any suitable connection, for example, welding to an upper surface of the upper frame member angle iron 63 are a plurality of spaced apart tube sections 75. An angle iron 77 is secured to the inside of the housing 51 above or closely adjacent to the upper opening of the tailgate 55 (FIG. 3). The angle iron 77 extends substantially the entire width of the housing 51. Secured to the angle iron 77 are a plurality of spaced apart tube sections 78 having generally the same diameter as the tube sections 75 secured to the screen 61. The tube sections 78 are adapted to fit in the spaces between the tube section 75 on the screen 61. When it is desired to place the screen within the housing 51, the screen is positioned within the housing with the tube sections 75 and the tube sections 78 on the angle iron 77 aligned with one another. A rod 79 is then passed through suitable openings in the sides of the housing 51 and through the openings in the tube sections to provide a pivotable mounting for the screen 61. The rod or hinge pin 79 is secured in position by any suitable arrangement, for example, by passing a pin 80 through an opening provided adjacent each end of the rod 79. It should also be noted that by removing the rod or hinge pin 79, the screen 61 may be readily removed. In this way, another screen having a different predetermined opening size between the horizontal and vertical members may be installed if desired. In order to secure the screen 61 in the desired location as described above with the lower end of the screen closer to the rotor 39, a bracket 81 (FIG. 7) includes an opening 83 therein adapted to receive the frame side member 67. The bracket is arranged on the side member 67 near the lower edge of the frame. The bracket 81 may be permanently secured to the side member 67 or may be easily removable to facilitate pivotable movement of the screen 61 without undue friction being generated between the bracket 81 and the inside of the housing 51. Also, by removably mounting the bracket 81, it is possible to use different brackets when it is desired to change the height of the lower edge of the frame for different strike off levels of the ground. A threaded opening 85 is provided in the side opposite the opening 83 in the bracket 81. A sleeve member 87 is adapted to pass through openings 91 in the housing 51 which openings are adapted to align with the openings 85 in the bracket 81. If the housing 51 includes a double wall construction, a suitable opening 93 for the sleeve 87 must be provided in an interior wall 95 of the housing. After arranging the side member 67 within the opening 83, a bolt 97 is received in the sleeve and threaded into the bore 85 in the bracket 81 to securely hold the screen 61 in the desired location. It should be noted that the illustrated embodiment includes two bolts passing through each side of the housing 51 for securing the screen 61. However, any number of bolts which is deemed sufficient may be provided. Since the screen 61 is pivotably mounted about the axis of the pin 79, it is possible to pivot the screen to a second, inoperative or storage position closely adjacent to the tailgate 55. In such a position, the screen 61 is substantially clear of the material dug up by the rotor 39 and tossed toward the rear of the housing 51. Such a position may be desirable when the ground material being worked is of sufficiently fine quality that large chunks of material or rocks are not present and therefore recycling the material is not necessary. The present invention also provides an arrangement for securing the screen 61 in the second storage position. The arrangement includes a plate member 99 secured to the lower frame member 65 preferably by welding. A pair of spaced apart flanges 101 extending generally perpendicular to the plane of the screen 61 are rigidly secured to the plate member 99. Each of the flanges 101 includes an opening 103 which openings are aligned with one another. A further flange 105 (FIG. 3) is secured to the inside surface of the tailgate 55. The flange 105 is adapted to be received between the flanges 101 on the screen 61 when the screen is placed in the second, storage position. In the second position, an elongated slot 107 in the flange 105 is aligned with the openings 103. On the outside of the tailgate 55, a first end of a flexible member 109 is secured to a reinforcing flange 119 by any suitable securement apparatus. For example, the flexible member may be a chain and the securement may include welding a first end of the flexible member or chain 109 to the reinforcing flange 119. A second end of the flexible member or chain 109 has a cotter pin 111 secured thereto, for example, by welding. In order to secure the screen in the second position generally parallel with the tailgate 55 (shown in phantom lines in FIG. 3), the chain 109 is passed beneath the lower edge 113 of the tailgate 55 and the cotter pin 111 is passed sucessively through the opening 103 in one of the flanges 101, the slot 107 in the flange 105, and the opening 103 in the other flange 101. A retaining pin 115 is then passed through an opening 117 in the end of the cotter pin 111 opposite the end to which the chain 109 is secured. In this way, the screen member is held securely in the second inoperative position by the flexible member 109. It should be noted, that the simple cotter pin arrangement disclosed herein is sufficiently strong to hold the screen 61 in the second position since the screen is not subjected to as much impact stress as when the screen 61 is in the first position. The additional bolts and more positive securing arrangement as described previously is desirable in the first position but is not essential in the second position. When the screen 61 is in the operative position, the chain 109 can be conveniently stored by providing an opening in the tailgate reinforcing flange 119. The cotter pin 111 can then be passed through the opening and retained by placing the retaining pin 115 through the cotter pin opening 117 (FIG. 4). In operation, the stabilizer machine moves forward along the ground and the rotor 39 is driven by the motor 49 to dig the material or soil over which the unit 31 passes. The material dug by the rotor 39 is comminuted to an extent within the housing 51 and is flung backwardly toward the rear of the housing 51. With the screen 61 according to the present invention secured in the first, operative position, particles of material which are to large to pass through the openings between the horizontal rods 69 and the vertical rods 71 are directed or deflected back toward the rotor 39. The deflected particles are subjected to the action of the rotor 39 to be further comminuted within the housing 51. This deflection cycle continues until the particles of material are small enough to pass through the openings in the screen. If the material being stabilized is sufficiently fine or the size of the dispensed particles is not as critical, the bolts 97 can be easily loosened and removed and the screen 61 can be pivoted about the rod member 79 into the inoperative position adjacent the tailgate 55. The chain 109 is then released from the reinforcing flange 119 and the cotter pin 111 is passed through the openings in the flanges 101 and the flange 105. The retaining pin 115 is inserted in the cotter pin 111 to secure the screen 61 in the storage position. The storage position is also useful when transporting the stabilizer machine. The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiment disclosed. The embodiment is to be regarded as illustrative rather than restrictive. Variations and changes may be made by other without departing from the spirit of the present invention. Accordingly, it is expressely intended that all such variations and changes which fall within the spirit and scope of the present invention as defined in the appended claims be embraced thereby.	The present invention relates to a soil stabilizer machine with a recycler screen. The soil stabilizer machine includes a horizontal rotor having a plurality of teeth along a periphery thereof. In operation, the machine moves along the ground and the rotor rotates to dig soil material. The soil dug by the rotor is comminuted by the rotor within a housing surrounding the rotor. Inside the housing and behind the rotor a screen is positioned to selectively permit particles of soil of less than a predetermined size to be dispensed on the ground behind the rotor and to selectively return particles of soil or rock greater than the predetermined size to the rotor to be further comminuted by the rotor. In a preferred embodiment, the screen is pivotably mounted within the housing between first and second positions. The screen can be secured in the first position to return particles of greater than the predetermined size or in the second storage position in which the particles dug up by the rotor are dispensed upon the ground behind the rotor without being sized.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip used for construction or demolition equipment which is adapted to be attached to a support and used in conjunction with, for example, a heavy-duty metal cutting shear, a plate shear, a concrete crusher, a grapple or other construction or demolition equipment. More particularly, the present invention relates to a replaceable tip secured to a support. 2. Description of Related Art For purposes of discussion herein, demolition and construction equipment may also be referred to as scrap handling equipment. The description of demolition equipment and construction equipment herein is not intended to be restrictive of the equipment being referenced. Demolition equipment, such as heavy-duty metal cutting shears, grapples and concrete crushers are mounted on backhoes powered by hydraulic cylinders for a variety of jobs in the demolition field. This equipment provides for the efficient cutting and handling of scrap. For example, in the dismantling of an industrial building, metal scrap, in the form of various diameter pipes, structural I-beams, channels, angles, sheet metal plates and the like must be efficiently severed and handled by heavy duty metal shears. Such shears can also be utilized for reducing automobiles, truck frames, railroad cars and the like. The shears must be able to move and cut the metal scrap pieces regardless of the size or shape of the individual scrap pieces and without any significant damage to the shears. In the demolition of an industrial building, concrete crushing devices, such as a concrete pulverizer or concrete crackers, are also used to reduce the structure to manageable components which can be easily handled and removed from the site. Wood shears and plate shears also represent specialized cutting devices useful in particular demolition or debris removal situations depending on the type of scrap. Also, a grapple is often utilized where handling of debris or work pieces is a primary function of the equipment. Historically, all of these pieces of equipment represent distinct tools having significant independent capital cost. Consequently, the demolition industry has tended to develop one type of tool that can be used for as many of these applications as possible. For illustrative purposes, the following discussion will be directed to metal shears. One type of metal shear is a shear having a fixed blade and a movable blade pivoted thereto. The movable blade is pivoted by a hydraulic cylinder to provide a shearing action between the blades for severing the work pieces. Examples of this type of shears can be found in prior U.S. Pat. Nos. 4,403,431; 4,670,983; 4,897,921; 5,926,958; and 5,940,971 which are assigned to the assignee of this application and which are herein incorporated in their entirety by reference. FIG. 1 illustrates a prior art, multiple tool attachment adapted to be attached to demolition or construction equipment, such as a backhoe (not shown). The multiple tool attachment is adapted to connect one of a series of tools or tool units to the demolition equipment. The tool attached in FIG. 1 is a metal shear 10 . The shear 10 includes a first blade 12 connected to an upper jaw 13 and a second blade 14 connected to a lower jaw 15 , wherein the jaws 13 , 15 are pivotally connected at a hub or main pin 16 to a universal body 18 . The body 18 is referred to as universal because it remains common to a series of tools or tool units in the attachment system. The universal body 18 is comprised of sides 19 , a bearing housing 20 and a yoke 21 . The upper jaw 13 and the lower jaw 15 pivot about the main pin 16 to form a movable jaw assembly 22 . At the end of the first blade 12 is a blade tip 24 . Details of the blade tip 24 are provided in FIGS. 3 and 4 wherein the blade tip 24 is comprised of a base 26 having a top side 28 , bottom side 30 and walls 32 , 34 therebetween. The base 26 of the blade tip 24 is a completely solid piece and the top side 28 of the base 26 is secured to a support 36 associated with the upper jaw 13 . Directing attention to FIGS. 1 and 2 the second blade 14 has associated with it a guide channel 38 which accepts and provides lateral support to the blade tip 24 and the first blade 12 . To minimize the deflection experienced under load by the first blade 12 and the blade tip 24 , the tolerance for the guide channel 38 is fairly low. In many applications, the first blade 12 and support 36 may be laterally displaced relative to the guide channel 38 such that upon entering the guide channel 38 the side of the blade tip 24 experiences rubbing and extensive wear during normal operation. This wear if not properly maintained can lead to the first blade 12 becoming jammed or stuck in the guide channel 38 . This condition is known as “stickers” in the industry. Stickers can develop when the clearance gap between the walls 32 , 34 of the tip 24 of the first blade 12 and the walls 40 , 42 of the guide channel 38 of the lower blade 14 become excessive enough to allow material to become wedged between these surfaces while shearing. Once the first blade 12 becomes stuck within the guide channel 38 , the shear 10 must oftentimes be decommissioned for repair. It is then necessary to build up the walls 32 , 34 of the tip 24 by welding to keep these gaps at a minimum. This process is very time consuming and costly and, depending on the material that the shear is processing, building up the tip could be required as often as once a week. Therefore, a tip design is desired that may be easily repaired or replaced when worn to minimize the downtime of a shear or other equipment. SUMMARY OF THE INVENTION On embodiment of the subject invention is directed to a tip for demolition and construction equipment having a discrete base with a top side, a bottom side and walls therebetween. The base also has a mounting surface on the top side of the base adapted to be secured to a support. The base furthermore has a central portion with a cutting edge, whereby the cutting edge is defined at the lowermost portion of the bottom side of the base. A recess extends into at least one wall of the base and the recess defines a recess upper side, an inner wall and a recess contour. An insert has a top side, a bottom side and walls therebetween with a cutting edge defined at the lowermost portion of the bottom side of the insert and generally aligned with the cutting edge of the base. The insert has a profile which generally conforms to the recess contour. An insert is secured within each recess. Another embodiment of the subject invention is directed to the inserts which are secured within each base recess. Yet another embodiment of the subject invention is directed to demolition and construction equipment utilizing such a tip. Yet another embodiment of the subject invention is directed to a method of securing inserts within a tip for demolition and construction equipment comprising the steps of providing a common bore through the insert and the walls of the base at each recess, positioning an insert within each recess, inserting a fastener therethrough; and securing the fastener against each insert within the recess. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is prior art and is a side view illustrating a metal shear incorporated into a universal body for a construction tool system; FIG. 2 is prior art and is a plan view of the shear in FIG. 1 ; FIG. 3 is prior art and is a front view of a blade tip; FIG. 4 is prior art and is a side view of the blade tip shown in FIG. 3 ; FIG. 5 is an enlarged portion of the encircled section in FIG. 1 , however, with the introduction of a blade tip in accordance with the subject invention; FIG. 6 is an exploded perspective view of the tip illustrated in FIG. 5 ; FIG. 7 is an exploded section view of the blade tip wherein one insert has a recess to accept a nut; FIG. 8 is a side view of the base associated with the blade tip; FIG. 9 is a profile of the insert associated with the blade tip; FIG. 10 is a side view of one insert having an internally threaded bore to accept a bolt; and FIG. 11 is a perspective view of an alternate embodiment of an insert which is indexable in accordance with the subject invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom” and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. FIG. 5 illustrates a blade tip 100 secured to a support 105 such as the upper jaw 13 of a jaw assembly 22 used in an industrial shear. It should be appreciated that although this tip 100 will be discussed in the context of an industrial shear associated with demolition equipment, it should be appreciated that such a blade tip 100 can be implemented on any type of equipment that shears, cuts, cracks, crunches or processes any type of material by motion of the blade tip. The blade tip 100 may be utilized, for example, as a shear tip, claw tooth, crusher tooth and any and all piercing/punching devices that currently exist or that may be developed. This tip has immediate applications for products such as shears, claws, grapples, crushers, crackers, rail breakers, multi-blade cutters, tree shears, ripper teeth, grinding teeth, shearing teeth and any mechanism that can utilize a disposable cutting part which is subjected to wear. Directing attention to FIGS. 6–9 , the tip 100 is comprised of a discrete base 114 having a top side 116 , a bottom side 118 and walls 120 , 122 therebetween. The base 114 has a mounting surface 124 on the top side 116 wherein the mounting surface 124 is adapted to be secured to the support 105 ( FIG. 5 ). The base 114 has a central portion 126 with a cutting edge 128 whereby the cutting edge 128 is defined at the lowermost portion 130 of the bottom side 118 of the base 114 . A recess 132 extends into at least one wall 120 , 122 of the base 114 . The recess 132 defines a recess upper side 134 , a recess inner wall 136 and a recess contour 138 ( FIG. 8 ). A second insert 184 will be described and is secured within a second recess 182 . Directing attention to insert 150 , the insert 150 has a top side 152 , a bottom side 154 and walls 156 , 158 therebetween. A cutting edge 160 is defined at the lowermost portion 162 of the bottom side 154 of the insert 150 and is generally aligned with the cutting edge 128 of the base 114 . Directing attention to FIGS. 8 and 9 , the profile 164 of the insert 150 generally conforms to the contour 138 of the recess 132 . The recess contour 138 is triangular and the profile 164 of the tip 150 corresponds to this shape. The insert 150 is secured within the recess 132 . Directing attention to FIG. 7 , when the insert 150 is secured within the recess 132 , the cutting edge 160 of the insert 150 is in approximate alignment with the cutting edge 128 of the base 114 . This is also true for insert 184 within the recess 182 . To provide additional support to the insert 150 within the recess 132 , the top side 152 of the insert 150 is positioned against the upper side 134 of the recess 132 . Redirecting attention to FIGS. 6 and 7 , the base 114 further includes a socket 166 extending into the inner wall 136 of the recess 132 . The insert 150 further includes a projection 168 extending from the wall 158 wherein the projection 168 fits within the socket 166 to support the insert 150 within the recess 132 . As illustrated in FIGS. 8 and 9 , the socket 166 and the projection 168 have matching shapes and are noncircular such that when the insert 150 is mounted within the recess 132 there is no relative rotation between the socket 166 and the projection 168 . As illustrated in FIGS. 6 and 7 , a common bore 170 extends through the insert 150 , the base 114 and the insert 184 . A fastener 172 passes through the common bore 170 and secures the inserts 150 , 184 within their respective recesses 132 , 182 . The fastener 172 may be a threaded bolt having a bolt head 174 and a threaded shaft 176 . The bore 170 may include a counter bore 173 within the insert 150 to accept the bolt head 174 and, furthermore, the bore 170 within the base 114 may have threads (not shown) to accept the threaded shaft 176 . While so far only a single recess 132 and a single insert 150 have been discussed in detail, a second recess 182 is associated with the opposite wall 122 of the base 114 and a second insert 184 is secured within the recess 182 in the same fashion as the insert 150 is secured within the recess 132 . When the fastener 172 has a bolt head 174 and a threaded shaft 176 , the bore 170 of the insert 178 may have a countersink 178 to accept the nut 186 to engage the threaded shaft 176 of the bolt 172 . In the alternative, an insert 190 having all of the features of insert 184 with the exception of a countersunk portion of the bore to accept the nut 186 may itself have a threaded bore 185 to accept the threaded shaft 176 of the bolt 172 , thereby alleviating the need for the nut 186 and the corresponding countersunk portion within the insert 184 to accommodate the nut 186 . FIG. 11 illustrates a perspective view of an insert 200 having a top side 216 , a bottom side 218 and an additional third side 220 with walls 222 , 224 therebetween. Extending from the wall 224 of the insert 200 is a projection 226 that is centered about a bore 228 extending therethrough such that the projection 226 and the contour of the first, second and third sides 216 , 218 , 220 are symmetric. As a result, with obvious modifications to the base 114 to accept the insert 200 , the insert 200 may be indexable such that multiple cutting edges 230 , 232 , 234 may be positioned at the lowermost portion 130 of the bottom side 118 of the base 114 and when one cutting edge becomes worn the insert 200 may be rotated such that a second cutting edge is exposed. The invention is also directed to a method of securing an insert 150 within a tip 100 for demolition and construction equipment comprising the step of providing a common bore 170 through the insert 150 and the walls 136 , 137 of the base 114 at each recess 132 , 176 . Each insert 150 , 178 is positioned within its respective recess 132 , 176 . A fastener 172 is inserted within the common bore 170 and the fastener 172 is then secured against each insert 150 , 178 within their respective recess 132 , 176 . It should be appreciated that under most circumstances the only maintenance for the tip 100 will be the replacement of the inserts 150 , 184 . However, it is possible to remove the base 114 from the support 36 to replace the entire tip 100 such that the tip 100 may be considered to be disposable. Furthermore, depending upon the application for which the tip 100 may be used, the material of the base 114 and the material of the tip 100 may be different. As a result of the tip 100 in accordance with the subject invention, machine down time and the associated expense may be significantly reduced because worn tips may be quickly and easily replaced. This invention has been described with reference to the preferred embodiments. Obvious modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations.	A tip for demolition and construction equipment has a discrete base with at least one recess therein to accept a replaceable insert. The insert has a projection that fits within a mating socket within the base. A threaded bolt may extend through a common bore within the insert and base to secure the insert to the base. The tip may also include a second opposing insert which is held within a respective recess by a common bolt.
You are an expert at summarizing long articles. Proceed to summarize the following text: [0001] This application claims the benefit of U.S. Provisional Application No. 60/903,699 filed on Feb. 27, 2007, and U.S. Provisional Application No. 60/903,721 filed on Feb. 27, 2007, both of which are incorporated herein by this reference in their entirety. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to methods and apparatus for use with a shallow bore hole under the floor of a drilling rig in which sections of drill pipe are temporarily placed before being connected to the drill assembly, and more particularly to methods and apparatus for supporting drill pipe sections in a house hole adjacent to a drilling rig. [0004] 2. Description of the Prior Art [0005] Drilling rigs are designed to drill wells deep into the earth's surface in order to extract materials such as oil, gas, etc. In order to drill effectively a great distance, the drill pipe consists of sections or “joints” of drill pipe or tubing which are continuously attached together at the drill assembly to obtain a pipe having a desired length. Such sections of drill pipe are typically 30 feet in length. In order to attach a new section of drill tubing to the existing pipe being used for the drill, the new section of drill pipe must be in a generally vertical position for attachment. Because of the weight and size of drill pipe sections, each such section of drill pipe requires support in order to be placed in a vertical orientation. In order to prepare a section of drill pipe for attachment, a common solution has been to provide a shallow bore hole adjacent to the much deeper drilling hole in the rig, into which such pipe sections are inserted in a generally vertical orientation prior to installation onto the main shaft of piping. Such shallow holes are commonly referred to as “mouse holes.” [0006] A mouse hole is typically lined with wider piping and used as a convenient location to store the next section of drill pipe. A typical mouse-hole is usually just slightly shallower than a section of pipe. Thus, when a section of pipe is lowered into the mouse-hole, it can rest on the bottom and lean against the walls of the mouse-hole to stay in a generally vertical orientation, with the top portion of the pipe section extending above ground in order to be accessible for removal and attachment to the main drill pipe. Once the drill pipe section is placed in the mouse hole, its position is generally upright and stable, allowing the equipment used to insert pipe section to be allocated to other uses. [0007] Generally pipe is unloaded from a truck or other delivery vehicle and placed on a pipe rack for storage. When a new section of pipe is needed, a crew brings pipe from the pipe rack using a cat line, air hoist or hydraulic winch up to the drilling floor and places it in the mouse-hole. [0008] By placing the new drill pipe section in the mouse hole, it can be prepared for attachment to the main drill pipe while a prior section of pipe is being drilled. The prior section of pipe is drilled into the ground until it reaches a depth where it is ready for the new pipe section to be attached. While this drilling is taking place, the new pipe section is hoisted out of the mouse hole, and maneuvered near the main drill bore in a generally vertical orientation. When the prior pipe section is drilled in far enough, the vertically oriented new pipe section is attached to it, and drilling continues. Under this method, drilling must stop roughly every thirty feet (the length of a typical section of pipe) to allow for the time to add another drill pipe section. [0009] In many cases, this process involves removing the kelley from the prior section chain of drill pipe, and moving the kelley into position over the new pipe section in the mouse-hole. The new pipe section is attached to the kelley, and raised out of the mouse-hole. The bottom of the new pipe section is attached to the end of the prior pipe section of the existing pipe chain. While drilling crews become very efficient in adding pipe sections, the process still takes considerable time, and when repeated multiple times for deep wells, this amount of non-drilling time is significant. Because of the time-consuming nature of adding drill pipe sections, it is desirable to provide methods and apparatus for more efficient and speedy attachment of drill pipe sections. [0010] Existing mouse hole support units are generally designed to be permanently mounted into or below the floor of a drilling rig, above the mouse hole itself. They are not portable. For new installations, it is a simple matter to dig out the mouse hole itself and then install the support unit into the floor of the rig over the mouse hole as the floor and rig is constructed. However, installing such a support unit in an existing drill rig is expensive and cumbersome since it will generally involve partially demolishing or replacing the floor of the drill rig in order to provide proper support for the unit. It is therefore desirable to provide a portable mouse hole pipe support unit, and/or mouse hole pipe support units that may be installed above or on top of an existing floor of a drill rig. [0011] Existing mouse hole support units also suffer from the drawback that they are provided in only one size, such that shims or slips are required in order for these support units to engage a given section of pipe. With these existing units, different shims or slips are required for engaging pipes having different diameters. Such mouse hole support units include a rotatable bowl surrounding an opening through which the pipe section is inserted. The circumference of the opening is designed to be larger than the largest pipe section to be used, and the circumference of the bowl is larger still. As a result, once a pipe section is inserted through the bowl and opening, it is necessary to insert a plurality of shims or slips between the pipe section and the bowl in order to hold the pipe section in place in the bowl before it can be rotated for attachment to the next pipe section. [0012] A typical drill pipe section may have two different diameters: a larger diameter at the ends of the section, and a narrower diameter along the middle portion of the drill pipe. The larger diameter at the end of the drill pipe creates an annular shoulder which can be used to prevent it from moving. The shims or slips are typically inserted adjacent to this annular shoulder to hold the pipe section in place when attaching one section of pipe to another, as described in U.S. Pat. No. 5,351,767. Once this attachment is achieved, the plurality of shims or slips must then be removed from the bowl so that the pipe section(s) may be removed. The insertion and removal of the shims or slips must be repeated for each pipe section that is inserted into the bowl, a process which takes considerable time. Different sizes of slips may be required for pipe section of different diameters. In addition, the slips and the frictional surfaces thereon tend to wear out from being constantly inserted and removed. It is therefore desirable to provide methods and apparatus for securely engaging pipes of different diameters in a mouse hole without the need for separate support shims or slips. SUMMARY OF THE INVENTION [0013] The present invention provides improved methods and apparatus for supporting and engaging drill pipe in a mouse hole that allows for multiple drill pipe sections or joints to be attached together before being attached to an existing drill string. The present invention is designed to allow for engagement and disengagement of drill pipe sections of various diameters without the need for manually inserting or removing support shims or slips. These features allow for speedy set up and attachment of drill pipe sections during drilling operations. The support unit of the present invention is also portable, and may be retrofitted into an existing drill rig platform. [0014] Embodiments of the present invention allow for the connection of multiple sections of drill pipe in a mouse hole by securing a given section of pipe in the hole and delivering a rotational force to secure that pipe section to another section of drill pipe placed above it over the mouse hole. In some embodiments, the rotational force may be provided by the support unit of the present invention. In alternative embodiments, the rotational force may be provided by an outside source such as an iron roughneck, with the support unit of the present invention holding the drill pipe section in a stationary position as such force is delivered. The unit then allows the connected pipe sections to be lowered and secured so the process can be repeated to connect multiple sections of drill pipe together in the mouse hole. The multiple sections of drill pipe may then be retrieved as a unit, and attached to the pipe string already being used to drill the well. This saves considerable time when extending the length of the main drill pipe string. Instead of attaching a single section of pipe to the main pipe string each time, the present invention allows for a pre-connected set of multiple pipe sections to be attached. Thus, for example, if the set in the mouse hole is made up of three attached pipe sections, the time for drilling the same depth may be speeded up by much as two thirds. [0015] The mouse hole of the present invention is different from standard mouse hole designs. Typically the depth of a mouse hole is slightly shorter than that of one section of pipe. The mouse hole of the present invention is at least twice as deep as such a standard mouse hole, if not deeper, in order to allow enough depth for the insertion of multiple sections of pipe, and to not limit the number of pipe sections that can be connected with the device at one time. Accordingly, the mouse hole should be of a depth to accommodate at least two or more sections of drill pipe. In one embodiment, the mouse hole accommodates three sections of drill pipe. It is to be appreciated that this greater depth is desirable in order to accomplish the connection of multiple sections of pipe together before those sections are removed as a unit from the mouse hole for attachment to the main drill pipe chain. [0016] The support units of the present invention are provided for installation over a mouse hole. A support unit may be mounted above or below the floor of the drill rig surrounding the mouse hole to prevent movement. Embodiments of the support unit include a frame which is positioned above the mouse hole, and an engagement/slip assembly. The engagement assembly is capable of securely engaging a pipe section so that it may be held in place by the support unit. A first pipe section is lowered into the mouse hole and engaged by the assembly, and a second pipe section is then placed adjacent to the first pipe section (end to end). The second pipe may then be rotated using an external source such as an iron roughneck or the like, in order to engage it with the first pipe being held by the support unit in the mouse hole. In some embodiments, the engagement/slip assembly is capable of rotational movement. In the embodiments having such a rotational assembly, this assembly acts to rotate the engagement/slip assembly, and hence rotate any pipe(s) held by that assembly to facilitate attachment to other sections of pipe. [0017] A large cylindrical opening is provided through the center of the frame for receiving a section of pipe that will extend through the opening into the mouse hole. In several embodiments, a plurality of movable support slips are provided around the inside of this opening for engaging a section of pipe inserted into the opening. The slips are capable of generally radial movement toward or away from the center of the opening. The slips move inward in order to engage a pipe section, and outward to release a pipe section. Skid plates, teeth or other rough frictional surfaces may be provided on the inwardly facing surfaces of the slips where they touch the pipe section in order to more securely engage the pipe section and prevent slippage. In several embodiments, the slips may be arcuate members, which may form a sectioned generally cylindrical clamping system. The slips need not be arcuate, however, as any suitably shaped set of slips may be provided so long as firm releasable engagement of the pipe section may be achieved. Individual slips (or pairs or groups of slips) separate from each other when moved outward in order to increase the size of the central opening to receive (or release) a pipe section. These slips come together when moved inward to decrease the size of the central opening to engage a pipe section. This allows for engagement with pipe sections having a wide variety of different diameters. In alternative embodiments, removable extensions may be provided on the slips to provide for prolonged wear of the slips by allowing for replacement of the removable extensions. In other embodiments, removable extensions may be provided for engagement with particularly narrow drill pipe sections. In such embodiments, frictional surfaces may be provided on the interior surfaces of the extensions where they come into contact with the drill pipe section. [0018] In several embodiments, the automated movement of the slips is controlled by lever assemblies or linkages which establish the radial paths along which the slip assemblies extend and retract in relation to the center of the mouse hole. In these embodiments, the extension and retraction (inward and outward movement) of the slips is imparted by the lever assemblies. In some embodiments, a first arm is provided that extends across and is pivotally attached to the top of a generally cylindrical wall that defines the large central opening of the support frame. One end of the first arm is pivotally attached to one or more of the slips, and the opposite end is pivotally attached directly or indirectly to a motion imparting member. Thus, as the opposite end of the first arm is pulled down, the first arm acts as a lever across the generally cylindrical wall, such that the other end of the first arm (attached to the slip(s)) is raised, thereby raising the slip(s) upward and outward from the center opening. This opens the central opening for receiving (or releasing) a pipe section. The downward motion of the opposite end of the first arm is accomplished by the motion imparting member pulling downward. The farther down this member pulls the first arm, the higher and farther the slips are raised upward and outward from the center of the opening. Force may be imparted to the movable members from any appropriate source such as electrical, hydraulic, pneumatic, or mechanical provided by motors, pistons, engines or the like. In some embodiments, a second arm is pivotally connected to the opposite end of the first arm forming an elbow. In these embodiments, the opposite end of the second arm is pivotally attached to a motion imparting member that is capable of moving up and down, thereby transferring this motion through the second arm to the first arm. [0019] It is to be appreciated that reversing this motion will cause the slips to move downward and inward toward the center of the opening. In particular, as each movable member moves up, it raises the opposite (or elbow) end of each first arm. This causes the other end of each first arm to travel downward and inward towards the center of the opening, bringing the slip(s) with it. This motion may be continued until the slips engage a pipe section in the opening, or until the slips are fully extended (preferably, but not necessarily flush with the upper surface of the frame) if no pipe is present. The movable member(s) impart sufficient force to the first arm (through the second arm, if used) to the slips to hold not only the weight of the pipe section engaged by the slips, but also the weight of other pipe sections attached thereto. [0020] In some embodiments, the upward and downward motion is imparted through a peripheral (sometimes annular) support structure surrounding a generally cylindrical support wall, to which each of the lever assemblies is pivotally connected, either directly or indirectly. The peripheral support structure rotates with the cylindrical support wall, lever assemblies and slips in order to allow the slips to be rotated as part of the pipe coupling process. In other embodiments, these structures do not rotate. As the peripheral support structure moves downward, it causes the slips to move upward and outward. This motion is accomplished through the lever action of the arms attached to the slips which govern their movement, pulling them up and away from the center, so that the slips move both outward and upward at the same time. Then, when the peripheral support structure moves upward, the lever action of the linkages moves the slips down causing the slips to extend toward the center so that they move downward and inward at the same time. In some embodiments, the peripheral (sometime annular) support structure is rotatable with the generally cylindrical support wall. In other embodiments, the peripheral structure is not capable of such rotation. [0021] When the slips are retracted in an outward and upward direction, a section of pipe may be lowered through the central opening and into the mouse hole. Once the pipe section has been vertically lowered to a desired position into the mouse hole, the peripheral support structure or other motion imparting device(s) are activated to compress the slips against the surface of the pipe. The force of the compression of the slips against the pipe section holds it in place. In addition, if the pipe is positioned such that its larger-diameter end portion is above the slips, the annular shoulder on the pipe also helps serve to prevent the pipe from falling though the opening and into the mouse-hole. It is to be appreciated that slips of different sizes and shapes may be attached to the linkages so long as the chosen configuration allows for capture and release of the particular drill pipe sections in use. [0022] In several embodiments, once a section of drill pipe is engaged by the slips, the slips are capable of rotating the pipe section to secure it to either the kelley or to another section of pipe while still in the mouse hole. In these embodiments, rotational movement is imparted to the peripheral structure which rotates with the central cylinder, thereby rotating the slips and the secured drill pipe section around a central axis. In some embodiments, the peripheral structure is attached directly or indirectly (e.g., to the cylindrical wall) to, or includes a large gear structure having a set of cogs or teeth around its circumference. In these embodiments, a motor or other rotational member having a smaller corresponding and interengaging gear is provided adjacent to the large gear, such that operation of the motor or other rotational member imparts motion from the smaller gear to the larger one, thereby rotating the entire support system, including the peripheral support structure, generally cylindrical support wall, lever assemblies and slips. [0023] In other embodiments, the peripheral support structure is not capable of rotational movement, but merely imparts the upward/downward movement necessary to extend and retract the slips. In some embodiments, the peripheral support structure is replaced by separate fixed-position lifting structures that are provided for each lever assembly or linkage. In these non-rotational embodiments, the rotational movement of the pipe section is imparted from an external source such as an iron roughneck or the like. [0024] In those embodiments using a peripheral support structure, it is important that upward and downward motion be imparted to the support structure evenly. In several embodiments, this is accomplished by means of lifting structures that are positioned around the peripheral support structure. At least two lift points should be used, and the lift points should preferably be equally spaced from each other. This allows for uniform upward and downward movement of the peripheral support structure. If two lifts are used, they should be positioned at opposite locations around the periphery of the support structure (i.e., about 180° apart); if three lifts are used, they should be equally spaced from each other (i.e., about 120° apart); if four are used, the equal spacing should be about 90° apart; etc. The lifting structures may be electrical, hydraulic, pneumatic, or mechanical with the lifting and lowering force provided by motors, pistons, engines or the like. [0025] In the rotating embodiments and in other embodiments, each lifting structure may be provided with a follower that may be positioned adjacent to the peripheral support structure. In these embodiments, it is preferred that the outer edge of the support structure have an annular form. The follower may be raised and lowered by the lifting structure. In some embodiments, these followers are in the form of a slightly arcuate plate that conforms to the curvature of the annular support structure. In the rotating embodiments, one or more wheels extend out from each follower above the annular support structure; and one or more additional wheels extend out from each follower below the annular support structure. As a result, in these embodiments, the wheels of each follower are deployed both above and below the annular support structure, sandwiching the support structure between them. When the lifting structure raises the follower, the wheels that are located below the annular support structure come up underneath and make contact with the lower surface of the annular support structure, transferring the upward motion to the annular support structure thereby raising it upward. Similarly, when the lifting structure lowers the follower, the wheels that are located above the annular support structure come down and make contact with the upper surface of the annular support structure, transferring the downward motion to the annular support structure thereby lowering it. The wheels on the followers are spaced sufficiently to allow the annular support structure to rotate freely with the generally cylindrical support wall, while staying sandwiched between them. All of the components of the system are made of durable preferably metal materials in order to transfer sufficient force to hold and rotate the heavy pipe sections that are placed into the invention. [0026] In the embodiments where the peripheral support structure is not capable of rotational movement, the lift(s) may be attached directly to the support structure. In alternative embodiments, follower(s) or linkage(s) may be provided with the lift(s) to attach the lifts to the peripheral support structure to permit raising and lowering of the support structure. In alternative embodiments, guides may be provided which extend out from each follower above and below the support structure, sandwiching the support structure between them. In these alternative embodiments, the guides may be attached to the peripheral support structure but this is not necessary. When the lifting structure raises the follower in the embodiments where the support structure is sandwiched between upper and lower guides, the guides located below the support structure transfer the upward motion to the support structure thereby raising it. Similarly, when the lifting structure lowers the follower, the guides located above the peripheral support structure come down transferring the downward motion to the support structure thereby lowering it. [0027] It is to be appreciated that in the non-rotating embodiments, the peripheral support structure may be replaced by separate coordinated lifts or lifting structures for each linkage, which raise and lower all of the linkages at the same time for even movement. In these embodiments, followers may be employed, but are not necessary. [0028] Once a subsequent section of pipe is properly secured to first pipe section in the mouse hole, the slips can be released, and the pipe chain lowered until the top of the uppermost pipe section is positioned for engagement by the slips. Then another pipe section may be attached, and so on, until the drill pipe chain has a desired length. At that time, these attached sections of pipe can be removed as a unit from the mouse hole and attached as a unit to the existing drill pipe string. [0029] It is therefore an object of the present invention to provide methods and apparatus for improving the efficiency of drilling operations through improved mouse hole drill pipe support systems. [0030] It is also an object of the present invention to provide methods and apparatus for reducing the time required to set up drill pipe sections or strings prior to installation into the main drill string. [0031] It is also an object of the present invention to provide methods and apparatus for supporting and engaging drill pipe in a mouse hole that allows for multiple drill pipe sections or joints to be attached together before being attached to an existing drill string. [0032] It is also an object of the present invention to provide methods and apparatus for securely engaging and disengaging drill pipe sections inserted into a mouse hole without having to manually insert or remove separate support shims or slips. [0033] It is also an object of the present invention to provide apparatus for supporting and engaging drill pipe in a mouse hole that may be mounted above, below or into the floor of a drill rig. [0034] It is another object of the present invention to provide portable apparatus for supporting and engaging drill pipe in a mouse hole that may be retrofitted onto an existing drill rig floor. [0035] Additional objects of the invention will be apparent from the detailed descriptions and the claims herein. BRIEF DESCRIPTION OF THE DRAWINGS [0036] FIG. 1 is a side perspective view of an embodiment of the apparatus of the present invention in a closed position. [0037] FIG. 2 is a top plan view of the embodiment of FIG. 1 . [0038] FIG. 3 is a side elevational view of the embodiment of FIG. 1 . [0039] FIG. 4 is a side cross-sectional view along line A-A of FIG. 3 . [0040] FIG. 5 is a perspective view of the embodiment of FIG. 1 with the support frame removed to show detail. [0041] FIG. 5A is a partially cut-away perspective view of the embodiment of FIG. 5 . [0042] FIG. 5B is a detail view of a portion of the embodiment of FIG. 5A . [0043] FIG. 6 is a side perspective view of an embodiment of the apparatus of the present invention in an open position. [0044] FIG. 7 is a top plan view of the embodiment of FIG. 6 . [0045] FIG. 8 is a side elevational view of the embodiment of FIG. 6 . [0046] FIG. 9 is a side cross-sectional view along line B-B of FIG. 8 . [0047] FIG. 10 is a perspective view of the embodiment of FIG. 6 with the support frame removed to show detail. [0048] FIG. 10A is a partially cut-away perspective view of the embodiment of FIG. 10 . [0049] FIG. 10B is a detail view of a portion of the embodiment of FIG. 10A . [0050] FIG. 11 is a rear perspective detail view of an embodiment of a lift and follower of the present invention. [0051] FIG. 12 is a front perspective detail view of an embodiment of a follower of the present invention. [0052] FIG. 13 is a side perspective detail view of an embodiment of a follower of the present invention. [0053] FIG. 14 is a side perspective view of an alternate embodiment of the apparatus of the present invention in a closed position. [0054] FIG. 15 is a side elevational view of the embodiment of FIG. 14 . [0055] FIG. 16 is a side cross-sectional view along line A-A of FIG. 15 . [0056] FIG. 17 is a top plan view of the embodiment of FIG. 14 . [0057] FIG. 18 is a detailed perspective view of the embodiment of FIG. 14 in a partially opened position. [0058] FIG. 19 is a detailed perspective view of the embodiment of FIG. 18 with the frame removed. [0059] FIG. 20 is a cross-sectional view of a portion of FIG. 19 . [0060] FIG. 21 is a detailed perspective view of the embodiment of FIG. 14 in a closed position with the frame removed. [0061] FIG. 22 is a cross-sectional view of a portion of FIG. 21 . DETAILED DESCRIPTION [0062] Referring to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, and referring particularly to the illustrated embodiments of FIGS. 1-10 , it is seen that the illustrated embodiment of the present invention includes a frame 21 having an upper surface 23 and a lower surface 25 separated by a plurality of supports 27 . Frame 21 is designed for placement above a mouse hole of a drilling rig. The depth of the mouse hole should be sufficient to accommodate the desired number of pipe sections to be attached together as a unit prior to installation in the main pipe string of the drilling rig. Frame 21 may be installed such that the lower surface 25 rests upon the existing floor of a drill rig, or upon the floor surrounding the mouse hole. Alternatively, frame 21 may be installed such that upper surface 23 is flush with or below the floor of the drill rig or mouse hole. In several embodiments, frame 21 and the components provided therein (described more fully below) are portable and may be removed and transported as a unit. [0063] At least one central opening is provided in upper surface 23 . In rotatable embodiments, such as those illustrated in FIGS. 1-2 , one or more plates 33 may be provided inside a larger opening 31 defining central opening 35 therein. In these rotatable embodiments, plates 33 preferably have an arcuate shape generally forming a circle so that plates 33 may rotate within opening 31 . In some non-rotatable embodiments, plates 33 need not rotate, so they may be of any suitable shape so as to define a central opening 35 . In some embodiments, larger opening 31 and plates 23 and/or 33 may be eliminated entirely as shown in FIGS. 14-22 . [0064] A generally cylindrical support wall 39 defining a hollow interior is provided inside frame 21 around opening 35 . A plurality of slips 41 are deployed in the hollow interior area of wall 39 , leaving another smaller opening 37 in the center for receiving a section of pipe. The tops of slips 41 may have a shape that conforms to the shape of opening 35 . In alternative embodiments, slips 41 may be of any shape that fits inside opening 35 and cylindrical wall 39 while still providing a central opening 37 for receiving a pipe section. The number and spacing of slips 41 should be established so that they may engage and hold a section of pipe. The inwardly facing surfaces of slips 41 may be provided with frictional surfaces 43 such as skid plates or teeth, which come into direct contact with a drill pipe section when the slips are engaged (closed) around the pipe to hold it firmly in place. In alternative embodiments, removable extensions 42 may be provided on slips 41 that can more easily be removed and replaced when worn and at a lower cost than replacing the slips 41 themselves. In such embodiments, frictional surfaces 43 are provided on the interior surfaces of extensions 42 where they come into contact the drill pipe section. [0065] It is to be appreciated that neither the support wall 39 nor the hollow interior thereof need be of uniform diameter over the length of their longitudinal axes, or that the hollow interior area itself be generally cylindrical. In some embodiments, the diameter of the support wall 39 will be greater in the area in which the slips are positioned than in other areas. It is also to be appreciated that the exterior of support wall 39 may be generally cylindrical as shown in the illustrated embodiments, but that any other suitable shape (square, rectangular, hexagonal, etc.) may alternatively be used. [0066] A plurality of lever assemblies or linkages are provided in conjunction with slips 41 . In several embodiments, these assemblies include upper arms 51 that act as levers. One end of each upper arm 51 is pivotally attached to one or more slips 41 at pivot 56 . The opposite end of each arm 51 is attached directly or indirectly to an upward/downward motion imparting member. In the illustrated embodiment shown in FIGS. 9 and 10B , it is seen that the opposite end of arm 51 is pivotally attached at 52 to a second arm 53 , and second arm 53 is linked at pivot 58 to a movable structure 63 . In the illustrated exemplary embodiment, structure 63 is an annular ring that encircles support wall 39 ; however, it is to be appreciated that in other embodiments structure 63 may be provided in any shape extending around the periphery of wall 39 . Each upper arm 51 extends across and is pivotally attached to the top of support wall 39 at 54 forming a lever, with this pivotal attachment 54 at wall 39 acting as the fulcrum. In alternative embodiments, lower arm 53 may be eliminated, and one end of upper arm 51 may be attached directly to an upward/downward motion imparting member such as structure 63 . This direct attachment may or may not be pivotal, depending on the type of motion imparting structure used. Structure 63 , is moved up and down, either directly or indirectly, by a lift 71 or other device as described more fully below. [0067] Comparing FIG. 5B with FIG. 10B , it is seen that as each upper arm 51 is pulled down at pivot 52 (either directly or through lower arm 53 or the like), arm 51 acts as a lever across pivot attachment 54 , such that the opposite end of upper arm 51 at pivot point 56 is raised, thereby raising the slip(s) 41 upward and outward from the central opening 37 . This opens the hollow interior of wall 39 for receiving (or releasing) a pipe section as shown in FIGS. 8-10 . As the motion imparting device(s) move downward, it forces slips 41 to move upward and outward. As this occurs, the lever assemblies govern the movement of slips 41 , pulling them up and away from the center, so that slips 41 move both outward and upward simultaneously. An example of this open position is illustrated in FIGS. 6-10 . The farther down the motion imparting member(s) pull upper arms 51 at pivot 52 , the higher and farther the opposite ends of upper arms 51 at pivot point 56 and slips 41 are raised upward and outward from the central opening 37 . The devices 71 that impart motion to structures such as 63 may be of any suitable form including without limitation electrical, hydraulic, pneumatic, or mechanical, such as motors, pistons, engines or the like. [0068] It is to be appreciated that upward motion from the motion imparting devices at pivots 52 of arms 51 will cause the slips 41 to move downward and inward toward the center of opening 37 . In particular, as each motion imparting device moves up, it raises end 52 of upper arm 51 , either directly or through lower arm 53 or the like. This causes the other end 56 of the upper arm 51 to travel downward and inward towards the center of the opening 37 , bringing the attached slip(s) 41 with it. This motion is used to engage the slips 41 against a pipe section in opening 37 , or to bring the slips to a closed position if no pipe is present as shown in the exemplary embodiment of FIGS. 1-5 . The motion imparting device(s) impart sufficient force through the lever assemblies to the slips 41 to hold not only the weight of the pipe section engaged by the slips, but also the weight of other pipe sections that may be attached thereto. [0069] It is to be appreciated that upward/downward motion imparting member(s) may be provided in numerous alternative embodiments. In the illustrated embodiments of FIGS. 1-10 , a single structure 63 is provided to which each of the lever assemblies is attached. Structure 63 in the form of a peripheral support member that conforms to the outer surface of wall 39 . As structure 63 moves downward, it forces the slips 41 to move upward and outward. As this occurs, the arms 51 (and/or linkages 53 ) attached to the slips govern their movement, pulling them up and away from the center, so that the slips 41 move both outward and upward at the same time. This open position is illustrated in FIGS. 6-10 . Then, when structure 63 moves upward, the lever action of the assemblies moves the slips 41 down causing the slips to extend toward the center so that they move downward and inward at the same time. This closed position is illustrated in FIGS. 1-5 . [0070] It is to be appreciated that in some embodiments, separate up/down motion imparting members may be provided for each lever assembly (as shown in FIGS. 14-17 ), or that different groups of lever assemblies may be operated by different motion imparting members. It is to be appreciated that different combinations of motion imparting devices and lever assemblies may also be used, and different linkages or combinations of linkages may be employed between devices 71 and lever arms 51 . When multiple motion imparting devices are used, the motion of the lever assemblies should be coordinated in order to impart consistent motion to each linkage, in order to raise and lower the slips 41 in a uniform manner. [0071] In the non-rotating embodiments, it is not necessary for slips 41 to rotate around opening 37 to rotate an engaged pipe section. Thus, the upward/downward motion may be imparted directly to each lever assemblies using its own lift 71 that may be more directly connected to the lever assembly, eliminating member 63 . An example of such lifting assemblies is shown in FIGS. 14-17 . [0072] However, in the rotatable embodiments, such as that shown in FIGS. 1-10 , it is generally desirable to separate the upward/downward motion imparting members from the remaining rotatable parts of the invention so that the slips (and the structures associated with them—levers, cylindrical wall, etc.) may rotate freely and independently of the upward/downward motion imparting members. An example of how this separation is accomplished is illustrated in the embodiments of FIGS. 1-13 . In these illustrated embodiments, it is seen that upward and downward movement is imparted to the lever assemblies and structure 63 by a plurality of lifts 71 . Each lift 71 engages structure 63 in a way that allows structure 63 to rotate along with wall 39 , the lever assemblies, and slips 41 independent of the lifts 71 themselves. As shown in FIGS. 10 and 13 , each lift 71 is provided with a follower 73 that is positioned immediately adjacent to structure 63 . [0073] Followers 73 are raised and lowered by lifts 71 . As exemplified in FIGS. 11-13 , followers 73 are in the form of angled or slightly arcuate plate(s) that conform to the curvature of the annular support structure 63 . One or more rotatable members 75 extend out from each follower 73 below the annular support structure; and one or more additional rotatable members 77 extend out from each follower 73 above the annular support structure. As a result, the rotatable members of each follower are deployed both above 77 and below 75 the annular support structure 63 , sandwiching the support structure between them. Members 75 and 77 are rotatable in order to minimize friction while in contact with annular support structure 63 when it is rotated along with wall 39 , the lever assemblies and the slips. It is to be appreciated that the followers may be provided in different forms so as to impart raising and lowering movement to annular support structure 63 . For example and without limitation, followers may be in the form of posts, brackets, webbing or the like; and members 75 and 77 may be provided in the form of plates, bearings or even gears with teeth that intermesh with corresponding teeth on structure 63 . In other embodiments, a single hydraulic or pneumatic source may operate a plurality of lifts, each lift being connected to a follower adjacent to the annular support structure 63 . [0074] In the exemplary illustrated embodiments of FIGS. 1-13 , when a lift or lifting structure 71 raises a follower 73 , the rotatable members 75 that are located below the annular support structure 63 come up underneath and make contact with the lower surface of the annular support structure 63 , transferring the upward motion to the annular support structure thereby raising it upward (and closing the slips 41 ), as shown in FIGS. 1-5 . Similarly, when the lifts or lifting structures 71 lower the followers 73 , the rotatable members 77 that are located above the annular support structure 63 come down and make contact with the upper surface of the annular support structure, transferring the downward motion to the annular support structure thereby lowering it (and raising the slips 41 ), as shown in FIGS. 6-10 . The rotatable members 75 , 77 on the followers 73 are spaced sufficiently to allow the annular support structure 63 to rotate freely with wall 39 , while staying sandwiched between them. [0075] Upward and downward motion must be imparted to annular support structure 63 in a way that allows this structure to stay relatively level. This is important in order to cause uniform movement of the slips 41 resulting in firm, even engagement of a pipe section. In several embodiments, this is accomplished by means of one or more motion imparting devices or lifts 71 that are positioned around the annular support structure 63 . It is preferred that the annular support structure 63 be lifted from at least two different locations in order to keep structure 63 in a relatively level position as it is raised and lowered. This may be accomplished using a single lifting mechanism that operates two or more lifting structures to lift annular support structure 63 . In some embodiments, two lifting structures 71 may be used; in others, three such structures may be used. In the illustrated embodiments, four lifting structures 71 are shown, although any suitable number of lifting structures or lifting locations may be used. It is preferred that the lifting structures or locations be positioned relatively equidistant from each other around the support structure 63 to keep it relatively level. Motion imparting device(s) or lifts 71 may be of any suitable form including without limitation electrical, hydraulic, pneumatic, or mechanical, such as motors, pistons, engines or the like. [0076] In the non-rotatable exemplary embodiment of FIGS. 14-22 , support structure 63 has been eliminated; however, it is to be appreciated that in other non-rotational embodiments, a peripheral support structure such as structure 63 may be used to assure uniform movement of the lever assemblies and slips. In rotational embodiments, support structure 63 is capable of rotating in conjunction with wall 39 in order to allow the slips and linkages to be rotated as part of the pipe coupling process. [0077] In other embodiments, support structure 63 is eliminated and motion imparting device(s) 71 are attached or linked more directly to the lever assemblies. Like support structure 63 , the motion imparting device(s) will cause the slips 41 to move downward and inward toward the center of opening 37 . In particular, as each motion imparting device moves up, it raises upper arm 51 at pivot 52 with or without a lower arm 53 . This causes upper arm 51 at pivot point 56 to travel downward and inward towards the center of the central opening 37 , bringing slip(s) 41 with it. This motion is used to engage the slips 41 against a pipe section in the opening, or to bring the slips to a closed position if no pipe is present. The motion imparting device(s) 71 impart sufficient force to slips 41 to hold not only the weight of the pipe section engaged by slips 41 , but also the weight of other pipe sections attached thereto. It is to be appreciated that in rotatable embodiments of the invention, motion imparting devices 71 may be separated from the lever assemblies to allow rotation, while still providing the desired upward/downward motion. [0078] In alternative embodiments, a separate motion imparting device 71 may be provided with each lever assembly, and/or with pairs of linkage assemblies, and/or in other combinations. The movement of these motion imparting devices 71 should be coordinated in order to impart consistent motion to all lever assemblies, in order to raise and lower the slips 41 in a uniform manner. [0079] In other embodiments, lifts 71 are pivotally connected directly or indirectly to the lever assemblies or linkages, whichever is the case, so structure 63 and separate followers 73 are not required. [0080] The rotatable embodiments of FIGS. 1-10 illustrate embodiments of the invention where the engagement/slip assembly rotates a first engaged drill pipe section to be joined with a second drill pipe section which is in a fixed position. In the rotational embodiments, rotational movement is imparted to the support structure 63 which rotates in conjunction with the support wall 39 , thereby rotating slips 41 and the engaged drill pipe section around the axis defined by the central opening 37 and wall 39 . In some of these rotatable embodiments, wall 39 and support structure 63 are attached directly or indirectly to a rotating mechanism, such as a gear. In the illustrated exemplary embodiment, a large gear structure 65 is attached to or incorporated into wall 39 having a set of cogs or teeth 66 around its circumference. In these embodiments, a motor or other rotational member 67 having a smaller corresponding and interengaging gear 68 is provided adjacent to the large gear 65 , such that operation of the motor or other rotational member imparts motion from the smaller gear to the larger one, thereby rotating support wall 39 , annular support structure 63 and everything attached to it, including the slips 41 and lever assemblies 51 and/or 53 . While a gear has been illustrated as a means of imparting rotation, other means may also be employed such as a belt system, chain driven sprockets, direct drive motor(s), or the like. [0081] In use, the slips 41 are retracted to an outward and upward position, opening the central opening 37 so that a section of pipe may be lowered through the central opening and into the mouse hole below. Once the pipe section has been lowered to a desired position into the mouse hole, the annular support structure or other motion imparting device(s) or lifts are activated to compress the slips 41 and/or the frictional surfaces 43 against the surface of the pipe. The force of the compression of the slips against the pipe section holds it in place. Because of the generally radial inward-outward motion of the slips, generally any pipe section having a diameter that is smaller than the opening 37 provided by the retracted slips may be engaged. Slips of different sizes or shapes may be used to change the size and/or shape of this opening at setup, and/or extensions 42 may be attached to the slips. However, once the slips (with or without extensions) have been installed, it is generally not necessary to insert, remove or change them out during operations. [0082] Once the first section of pipe has been grasped by the slips, another section of pipe is then positioned adjacent to the pipe being held by the slips. In the stationary embodiments of the invention, the slips hold the pipe section in a fixed position, and rotational movement is supplied from an external source to join the pipe sections together. In the rotational embodiments of the invention, the rotational movement is imparted to the support wall 39 and/or support structure 63 which rotates the linkages and slips. This causes the held section(s) of pipe to rotate relative to the new section, causing them to be joined together. The slips are then retracted by downward movement of the annular support structure or other motion imparting device(s) or lifts, allowing the pipe section to be removed, or lowered further into the mouse hole and engaged again. The process may then be repeated for subsequent pipe sections. When enough pipe sections are connected together in the mouse hole, the string of sections is removed and attached as a group to the main string of the drill rig. [0083] It is to be understood that variations and modifications of the present invention may be made without departing from the scope thereof, and that different combinations of the various features identified herein are contemplated within the scope of the invention. It is also to be understood that the present invention is not to be limited by the particular embodiments described or illustrated herein, but only in accordance with the appended claims when read in light of the foregoing specification.	The present invention provides improved methods and apparatus for supporting and engaging drill pipe in a mouse hole that allows for multiple drill pipe sections to be attached together before being attached to an existing drill string. The present invention is designed to allow for engagement and disengagement of drill pipe sections of various diameters without the need for manually inserting or removing support shims or slips. Embodiments of the invention provide for rotation of the engaged drill pipe sections to assist in connection to another drill pipe section. These features allow for speedy set up and attachment of drill pipe sections during drilling operations. The support unit of the present invention is also portable, and may be retrofitted into an existing drill rig platform.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the priority of Provisional Application for Patent Ser. No. 60/897,456 filed on Jan. 25, 2007 which is incorporated herein by reference. FIELD OF INVENTION [0002] The present invention relates to a window shade or window covering utilizing a separator system for a control mechanism of the window shade or window covering. In particular, the present invention relates to a control mechanism for a window covering providing a disengagement function that may be utilized to prevent or minimize damage to the control mechanism as a result of unintended force on the window shade or window covering. BACKGROUND OF INVENTION [0003] There are numerous types of window shades and window coverings. Examples of such include Venetian blinds, Roman shades, and cellular shades. Typically such window shades and window coverings include a head rail having a light blocking or light shading element suspended from the head rail by one or more suspension cords. These window shades and window coverings also usually include a bottom rail that is also suspended from the head rail to provide additional weight to extend and straighten the light blocking or light shading element. Positioning of the suspension cords is adjustable through different mechanisms including cord locks, clutches, and winding drums. For example, with a clutch based control mechanism, a user controls the raising and lowering of the window covering by pulling on a control cord, which causes the clutch to drive the rotation of the clutch axle. Rotation of the clutch axle in one direction causes the suspension cords to unwind and lower the window covering. Raising of the window covering may be accomplished by applying an upward force to the bottom rail such that the clutch rotates the clutch axle in a second direction that winds the suspension cords and raises the window covering. [0004] A problem that occurs with window coverings utilizing a clutch control mechanism that has been observed is that the user sometimes will attempt to lower the window covering by pulling down on the bottom rail rather than by through use of the control cord. When a user pulls down on the bottom rail and forces the window covering closed in this manner, the clutch mechanism may be irreversibly damaged. [0005] What is needed is a device that provides for separating excessive force exerted directly on a window covering from the clutch control mechanism such that the damage that may be caused thereto is avoided. The present invention meets these desires and overcomes the shortcomings of the prior art. SUMMARY OF THE INVENTION [0006] The present invention is directed to a separation system for a control mechanism in a window covering. An embodiment of the present invention is a control mechanism including a torque-selective separator positioned on a drive axle upon which is also positioned a clutch mechanism. The drive axle comprises a clutch axle and a winding axle. [0007] The clutch mechanism may be a conventional clutch mechanism as is known in the art of window coverings. The clutch mechanism is preferably mounted about the clutch axle so as to cause the clutch axle to rotate in the desired manner. The clutch mechanism may also be connected to a control cord. When a user pulls on the control cord, the clutch causes the clutch axle to rotate. Under normal operating conditions, rotation of the clutch axle causes concurrent rotation of the winding axle such that the as the winding axle is rotated, the suspension cords are wound about one or more winding drums, and thereby, raising the window covering. Any clutch mechanism known or that may become known for use in a window covering may be utilized with the present invention. [0008] Mounted on and in a coaxial relationship with the drive axle is the separator system. The separator system is preferably formed from a body having a first portion and a second portion that are mated to one another to form the body. The body also comprises a first end and a second end. The first end defines a first recess that is configured to closely surround and circumscribe a distal end portion of the clutch axle. The second end similarly defines a second recess that is configured to closely surround and circumscribe a proximal end portion of the winding axle. Preferably, the first portion of the body and the second portion of the body each define a portion of the first and second recess. Preferably, the walls of the first and second recesses are rigid, and do not flex when force is exerted upon the walls. The first and second recess may be separated by a center partition if desired. [0009] It is preferred that the first and second recesses define a cross section that substantially matches the cross section of the portion of the drive axle, e.g., the clutch axle or winding axle, that is circumscribed. Preferably, the drive axle is non-resilient and does not compress when force is exerted upon the drive axle. Preferably, the drive axle does not contain a cavity or slot that would allow the width of the axle to be reduced in response to compression force. [0010] The drive axle and corresponding recess can define a cross section of any shape so long as the shape of the cross section creates a frictional force between the drive axle and recess when the drive axle is rotated. Such frictional force can be created from a variety of cross section components, including, but not limited to the corners of a polygonally shaped cross-section, the non-symmetrical sides of an oval-shaped cross-section, or ribs, teeth, or other protrusions projecting from a generally circular cross-section. [0011] The drive axle preferably defines a polygonal cross section. For example, the drive axle may define a square-shaped cross section. In this example, the first and second recesses would define a square-shaped cross section through which the drive axle is passed and closely circumscribed. The drive axle may also define a generally circular cross section, such as an oval-shaped cross section, in which case the first and second recesses would also define a generally circular cross section. The drive axle may also define a generally circular cross section with ribs, teeth or other protrusions projecting from its outer surface. In such a case, the first and second recesses would define a circular cross section containing slits, groves or other indentations that complement the protrusions of the projecting from the drive axle. [0012] Preferably, the first and second portions of the body provide equal portions of the recess such that the body is rotationally balanced about the drive axle. [0013] In some embodiments the cross section of the first and second recess need not match the cross section of the clutch axle or winding axle. Instead, for example, a square shaped cross section clutch axle and winding axle may be used with an octagonal recess. [0014] The first portion and the second portion of the body are movable relative to one another such that they are moveable from a mated position to an unmated position. In the mated position, the first portion and the second portion form the recess in the separator and are preferably held together by at least one biasing member, such as a spring clip. Any biasing members known in the art can be used to hold together the first portion and the second portion. Such biasing members include elastic bands, magnets, or any variety of spring. [0015] When the first portion and second portion of the body are in a mated position, the separator is preferably press fit with the drive axle. Under normal conditions, the press fit enables rotational force of the clutch axle to be transferred to the winding axle. As such, as the clutch is manipulated by the user through pulling on the control cord, the clutch axle is rotated, which causes concurrent rotation of the winding axle. [0016] As discussed above, a problem that has been observed occurs when a user attempts to lower the window covering by pulling on the bottom rail or accidentally pulls on the bottom rail. This excessive force on the bottom rail, in prior art systems, caused damage to the clutch mechanism. With the present invention, when an excessive force is exerted on the winding axle by way of a pulling force being exerted on the suspension cords, e.g., a user pulling on the bottom rail suspended by the suspension cords, the separator enables the force to not be exerted on the clutch mechanism. [0017] For example, when the first portion and second portion of the body are in a mated position, as a force is exerted on the winding axle, this force is transferred via the separator to the clutch axle and the clutch mechanism. If the amount of force exceeds a threshold level, which is less than the amount of force that would cause damage to the clutch, the winding axle is caused to rotate relative to the separator. As the winding axle rotates, due to the shape of the cross section thereof, the force exerted by the spring clip is overcome and the first portion and the second portion of the body are pried apart from one another and moved into an unmated position. As such, the winding axle is therefore able to rotate independent of the clutch axle, and the force exerted upon the winding axle is not transferred to the clutch axle or the clutch mechanism. [0018] In one embodiment, the cross sections of the clutch axle and the winding axle—as well as the first recess and the second recess—are of a regular polygon, such as a square. With the square-shaped cross section example, as the winding axle is rotated one quarter turn relative to the clutch axle, the spring clips cause the first and second portions of the body to return to a mated position. If the excessive force is still being exerted, the first and second portions of the body will again be pried apart and the winding axle rotated a quarter turn independent of the clutch axle, and then the body is returned to a mated position by the spring clips. This process continues until the force exerted on the winding drum does not exceed the threshold level. This threshold amount of force depends on the clutch mechanism in use. The threshold amount of force need only be less than whatever amount of force would cause damage to the clutch mechanism. [0019] In the embodiment discussed, the body of the separator is constructed with an assembly of two movable parts between which are defined the recesses for the axles. The number of parts can be any plurality desired. Also in the embodiment discussed, the clutch axle is detachably secured to the separator such that as the body is moved to an unmated position, the clutch axle can rotate relative to the separator. In an alternative embodiment, the clutch axle may be fixedly secured to the separator instead of by way of a press fit mount. In this alternative embodiment only the portion of the body that connects to the winding axle is moveable or adjustable to allow rotation of the winding axle relative to the separator, and in turn, relative to the clutch. [0020] In the previous embodiment, the coaction of the rotation of the winding axle and the compression of the spring clips cause the body of the separator to automatically move between a mated and an unmated position. In another alternative embodiment, the mechanism utilized to press fit the body to the axle may be releasable, yet not automatically re-engaged with the axle. In other words, if the threshold amount of force is exerted on the winding axle, the body of the separator is moved to an unmated position and thereby allowing the winding axle to rotate independent of the clutch axle, but is not caused to automatically return to a mated position. Instead, the reestablishment of the separator with the winding axle is achieved manually. [0021] The present invention has thus far been discussed in the context of a device utilized to prevent damage to a clutch mechanism. The present invention may also be used to provide a control mechanism for a window covering that may be operated either by a control cord, or by way of directly pulling or raising of the bottom rail, such as with a cordless window covering. In other words, the separator system may enable a user to pull down on the bottom rail of a window covering to lower the light blocking element, but not damage the clutch mechanism. Raising of the bottom rail is then achieved by applying an upward force to the bottom rail. If desired, the same control mechanism can include control cords to allow the user to raise and lower the window covering with the control cord. [0022] In yet another embodiment, the control mechanism may include a biasing mechanism such as found in cordless window covering applications. Examples of suitable devices are found in pending application Ser. No. 11/591,718, which was filed on Nov. 2, 2006 and application Ser. No. 11/392,340, which was filed on Mar. 29, 2006, each of which are incorporated herein by reference. An upward bias on the bottom rail and the commensurate rotational force on the winding axle may be provided by the biasing mechanism. When the user lifts directly on the bottom rail, the force exerted by the biasing mechanism may overcome the compressive force of the spring clips such that the winding axle is disengaged from the clutch axle, and the winding axle is then enabled to raised the window covering without transferring the rotational force to the clutch mechanism. BRIEF DESCRIPTION OF THE DRAWINGS [0023] In the drawings, [0024] FIG. 1 is a perspective view of a cellular window shade utilizing a separator system for a control mechanism in accordance with an embodiment of the present invention; [0025] FIG. 2 is a top plan view of a head rail of FIG. 1 ; [0026] FIG. 3 is a partial perspective view of the separator system engaged with the drive axle and in a mated position; [0027] FIG. 4 is a partial side elevational cross sectional view the separator system of FIG. 3 ; [0028] FIG. 5 is a partial perspective view of the separator system disengaged from the drive axle and in an unmated position; [0029] FIG. 6 is a partial side elevational cross sectional view the separator system of FIG. 5 ; [0030] FIG. 7 is side-elevation view of the separator system engaged with the drive axle and in a mated position wherein the drive axle and first recess have an oval shaped cross-section; [0031] FIG. 8 is a side-elevation view of the separator system shown in FIG. 7 disengaged from the drive axle and in an unmated position; [0032] FIG. 9 is side-elevation view of the separator system engaged with the drive axle and in a mated position wherein the drive axle has a generally circular cross-section containing U-shaped protrusions and the first recess has a generally circular cross-section with U-shaped indentations; and [0033] FIG. 10 is side-elevation view of the separator system engaged with the drive axle and in a mated position wherein the drive axle has a generally circular cross-section containing V-shaped protrusions and the first recess has a generally circular cross-section with V-shaped indentations. DESCRIPTION OF PREFERRED EMBODIMENT [0034] The invention disclosed herein is susceptible to embodiment in many different forms. The embodiment shown in the drawings and described in detail below is only for illustrative purposes. The disclosure is intended as an exemplification of the principles and features of the invention, but does not limit the invention to the illustrated embodiments. [0035] Referring to FIG. 1 , a cellular window 10 covering is shown. Window covering 10 includes a head rail 12 , a light blocking element, such as cellular structure 14 , a bottom rail 16 , a control cord 18 , and suspension cords (not shown). Window covering 10 may be opened by raising bottom rail 16 towards head rail 12 such that cellular structure 14 is collapsed and gathered on the bottom rail 16 . Raising of the bottom rail 16 may be effected by the user lifting the bottom rail such that the clutch mechanism ( FIG. 2 ) causes the suspension cords to be wound. Alternatively, the manipulation of the control cord 18 can be used to raise the bottom rail 16 . Lowering of the bottom rail 16 and closing of the window covering 10 may be done by manipulation of the control cord 18 , which causes the clutch mechanism to unwind the suspension cords, and thereby lower the bottom rail. [0036] As discussed, one problem that has been observed is that users of the window covering 10 sometimes attempt to close the window covering by pulling downward on bottom rail 16 . Conventional clutch mechanisms are typically designed to lock the window covering in a vertical position so that once positioned, the window covering does not close unintentionally. As such, if a user pulls too hard on the bottom rail, the resultant excessive force against the clutch lock can irreparably damage the clutch. [0037] Referring to FIG. 2 , an embodiment of the present invention that remedies the aforementioned problem is shown. Head rail 12 defines a channel in which various control components are located. Provided in the present embodiment is a drive axle comprising a winding axle 20 and a clutch axle 22 . The winding axle has mounted thereon a pair of winding drums 24 , 26 , which are supported by supports 28 and 30 . Winding axle 20 defines a proximal end portion 32 . Clutch axle 22 defines a proximal end portion 34 that is secured with clutch mechanism 36 , and a distal end portion 38 . The distal end portion 38 of the clutch axle 22 and the proximal end portion 32 of the winding axle are connected to one another by way of separator system 40 . In a preferred embodiment, the surface of the winding axle 20 and the clutch axle 22 is non-resilient and does not substantially compress when force is exerted upon it. [0038] A more detailed explanation of the separator system 40 is provided with reference to FIGS. 3-6 . Referring to FIGS. 3 and 4 , the separator system 40 is shown secured with winding axle 20 and clutch axle 22 . Separator system 40 includes a body 42 having a first portion 44 and a second portion 46 . Body 42 generally defines a first end 48 and a second end 50 . First portion 44 and second portion 46 are press fitted with the proximal end portion 32 of winding axle 20 and distal end portion 38 of clutch axle 22 by spring clips 52 and 54 . [0039] When first portion 44 and second portion 46 are in a mated position as shown in FIGS. 3 and 4 , body 42 defines a first recess 56 extending proximally from the first end 48 and a second recess 58 extending distally from the second end 50 . When in the mated position as shown, the first recess 56 and the second recess 58 define a square-shaped cross section. The cross section of the first recess 56 and the second recess 58 are configured to circumscribe the proximal end portion 32 of winding axle 20 and distal end portion 38 of clutch axle 22 , respectively. If desired, a partition 60 can be provided to separate the first recess 56 and the second recess 58 . In a preferred embodiment, the first recess 56 and second recess 58 contain rigid walls that do not flex when force is exerted upon the walls. [0040] When first portion 44 and second portion 46 are in a mated position, the body 42 of separator 40 connects the winding axle 20 and the clutch axle 22 such that force exerted on either of the winding axle 20 or clutch axle 22 is translated to the other. Thus, in normal operation, the winding axle 20 and clutch axle 22 function as an integral drive axle. [0041] Referring to FIGS. 5 and 6 , if a user exerts a pulling force on the bottom rail 16 ( FIG. 1 ) to cause it to lower, a resulting rotational force on winding axle 20 will drive the rotation of the winding axle 20 , causing the first portion 44 to separate from the second portion 46 of body 42 . Due to the geometries of the winding axle 20 , the clutch axle 22 , the first recess 56 , and the second recess 58 , if sufficient force is exerted, the compressive force of spring clips 52 and 54 are overcome. This allows first portion 44 of body 42 to separate from second portion 46 of body 42 . As such, winding axle 20 is permitted to rotate independent of the separator 40 , as well as the clutch axle 22 and clutch 36 . As the winding axle 20 continues to rotate, the geometry of first recess 56 is again brought into alignment with winding axle 20 , and spring clips 52 and 54 cause first portion 44 and second portion 46 to return to a mated position such as shown in FIGS. 3 and 4 . Guides 60 and 62 may be provided to assist in maintaining the desired alignment of the first portion 44 and the second portion 46 . If the excessive force is still being exerted, the first portion 44 and second portion 46 of the body 42 will again be pried apart and the winding axle 20 rotated a quarter turn independent of the clutch axle 22 , and then the body 42 is returned to a mated position by the spring clips 52 and 54 . This process continues until the force exerted on the winding drum does not exceed the threshold level. Once the excessive force is removed, the first portion 44 and second portion 46 of body 42 stay in a mated position and the clutch axle 22 and winding axle 20 again are connected so as to rotate synchronously. The force exerted by spring clips 52 and 54 in this embodiment can be provided by other mechanisms such as elastic bands, magnets, or springs. [0042] Referring to FIGS. 7 and 8 , an alternative embodiment of the separator system 40 is shown with an oval-shaped winding axle 120 . The oval-shaped first recess 156 in this embodiment corresponds to the shape of the winding axle 120 . The clutch axle and second recess (not shown) of this embodiment may also be oval shaped to create a consistent shape on both sides of the separator 40 . [0043] In this embodiment, a rotational force on winding axle 120 in the direction of arrow A or in the direction opposite to arrow A will cause first portion 144 to move in the direction of arrow B and will cause second portion 146 to move in the direction of arrow C. Such movement creates a separation between first portion 144 and second portion 146 such that oval-shaped winding axle 120 is permitted to rotate independent of separator 40 . [0044] Referring to FIG. 9 , an alternative embodiment of the separator system 40 is shown with a winding axle 220 having a generally circular cross-section. U-shaped protrusions 250 and 252 extend from winding axle 220 . The generally circular-shaped first recess 256 of this embodiment contains U-shaped indentations 258 and 260 that correspond to the U-shaped protrusions 250 and 252 . [0045] Referring to FIG. 10 , another alternative embodiment of the separator system 40 is shown with a winding axle 320 having generally circular cross-section. V-shaped protrusions 350 and 352 extend from winding axle 320 . The generally circular-shaped first recess 356 of this embodiment contains U-shaped indentations 358 and 360 that correspond to the V-shaped protrusions 350 and 352 . [0046] The positioning of the protrusions is not limited to the positions described in the disclosed embodiments. The protrusions 250 , 252 and 350 , 352 shown in FIGS. 9 and 10 are located on opposite sides of the winding axle 220 , 320 . The protrusions can also be placed less than 180 degrees apart from each other. Alternatively, one protrusion or more than two protrusions can extend from the winding axle. The indentations in the first recess may also be positioned to correspond with the alternative protrusion placement. [0047] While the embodiments discussed include axles and recesses with square, oval, or circular cross-sections, other shapes can be used. For example, polygonal shapes such as hexagons or octagons can be used. Other generally circular or generally polygonal shapes can be used so long as the shape of the cross section creates a frictional force between the drive axle and recess when the drive axle is rotated. [0048] Although the embodiments discussed describe a spring clip used as a biasing member, other biasing members known in the art can be used to hold together the first portion and the second portion. Such biasing members include elastic bands, magnets, or any variety of spring, including leaf springs, coil springs, and torsion springs. [0049] Another embodiment of the present invention can contain no biasing member at all, such that the body does not automatically re-engage with the axle after the body has been released. In this alternative embodiment, the reestablishment of the separator with the winding axle is achieved manually. [0050] Also, the embodiments discussed describe a separator system wherein the winding axle is disengageable from the separator system. It is also contemplated that the winding axle may be fixedly secured with the separator system, yet the clutch axle may be detachably secured with the separator system. In this configuration, if the rotational force exceeds the threshold level, the winding axle and separator system continue to rotate together while disengaged from the clutch axle. [0051] The foregoing description and the drawings are illustrative of the present invention and are not to be taken as limiting. Other arrangements of the engagement structure may be implemented. Such variations and modifications are within the spirit and the scope of the present invention and will be readily apparent to those skilled in the art in view of the scope of the invention as claimed herein.	The present invention relates to a window shade or a window covering having a control mechanism for raising and lowering the window covering. The control mechanism is provided with a separator system. In particular, the present invention relates to a control mechanism with a separator system that provides a disengagement function to prevent or minimize damage to the control mechanism as a result of unintended force on the window shade or window covering. The separator system utilizes a body movable between a mated position where a clutch axle and a winding axle move synchronously, and an unmated position where the winding axle is allowed to rotate independent of the clutch axle.
You are an expert at summarizing long articles. Proceed to summarize the following text: This is a continuation of application Ser. No. 06/535,041, filed Sept. 23, 1983, which is itself a continuation of application Ser. No. 337,592, filed Jan. 7, 1982. This invention relates to moveable bulkheads for use in swimming pools and more particularly to a novel wheeled supporting system provided with means for removing the load of the bulkhead from the wheels when the bulkhead is in a stationary position. BACKGROUND OF THE INVENTION It is the present practice in the art to fabricate moveable bulkheads for swimming pools with supporting wheels mounted on the ends of the bulkhead with the wheels being positioned on tracks that extend along the length of the pool. Prior art supporting wheels have rim portions formed of hard plastic and rubber materials due to the smooth, quiet operational characteristics of such wheels when operated on tracks formed by stainless steel portions of the gutter. With the advent of larger pools and longer and heavier bulkheads a problem has been present in that wheels having rim portions formed of hard plastic and rubber materials become deformed under the increased loadings and take an out-of-round "set" or configuration when they remain stationary under load for extended periods of time. As a result, the deformed wheels resist movement and are no longer smooth in operation. Another problem has been present in that the supporting wheels for such bulkheads inherently tend to bind, causing canting and jamming that arrest movement when the bulkhead is being repositioned. SUMMARY OF THE INVENTION In general, the present invention uses novel supporting carriages for mounting the bulkhead on its tracks, which carriages include jacking means for selectively raising and lowering the above mentioned supporting wheels between upper unloaded positions wherein the wheels are clear of their track, and a lower loaded position wherein the wheels engage their track and thereby moveably support the bulkhead. It is another object of the present invention to provide a swimming pool bulkhead that comprises novel supporting carriages that include bearing plates which can be selectively moved into load supporting positions on the tracks wherein the load of the bulkhead is distributed over relatively large load supporting areas of the tracks. It is another object of the present invention to provide a swimming pool bulkhead that includes load distributing bearing plates for selective engagement with the tracks and adjustable jacking means for distributing the load along the linear length of the bearing plates. It is another object of the present invention to provide a swimming pool bulkhead that comprises novel supporting carriages provided with selectively positionable load supporting bearing plates, and adjustable mounting means for accurately aligning the supporting carriages and bearing plates with respect to their tracks. It is still another object of the present invention to provide a swimming pool bulkhead that includes supporting wheels for movement of the bulkhead along its tracks, and supporting carriages for selectively relieving said wheels from their load, said bulkhead being uniquely adapted to shift laterally with respect to its supporting wheels and tracks when the bulkhead is being moved, thereby preventing binding at said wheels. Hence, canting of the bulkhead is prevented or relieved, with the result that the bulkhead can be readily moved and repositioned without jamming. Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiments of the invention is clearly shown. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial perspective view showing a typical swimming pool with a bulkhead of the present invention installed therein; FIG. 2 is a top elevational view showing the frame structure of a bulkhead constructed in accordance with the present invention; FIG. 3 is a side elevational view corresponding to FIG. 2; FIG. 4 is a side elevational view of a supporting carriage comprising a portion of the bulkhead of the present invention; FIG. 5 is a partial end sectional view showing the carriage of FIG. 4 mounted on an end plate of the bulkhead of the present invention; FIG. 6 is a partial side elevational view showing a modified carriage that comprises a modified embodiment of the present invention; and FIG. 7 is an end sectional view showing the modified carriage of FIG. 6. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring in detail to the drawings, FIG. 1 illustrates a typical swimming pool, indicated generally at 20, which includes a stainless steel gutter construction, indicated generally at 22. A bulkhead constructed in accordance with the present invention is indicated generally at 24 and is moveably mounted on tracks formed by gutter construction 22 and functions to divide the pool into various selected activity areas. With reference to FIGS. 1-3, bulkhead 24 includes a frame constructed as a truss including longitudinal frame members 28 and 30, transverse frame members 34, 36, 40 and 42. As seen in FIG. 1, the truss frame is covered with side walls 44 and a top walkway 46, and includes one or more air compartments 32 to provide flotation support for the structure. As seen in FIGS. 2 and 3, each end of bulkhead 24 is moveably supported by a supporting carriage, with the locations of these carriages being indicated generally at 50 in FIGS. 2 and 3. Each carriage includes a removable protective cover 51. Reference is next made to FIGS. 4 and 5, which illustrate in detail the structural components of the supporting carriages 50. Each supporting carriage 50 functions as a jacking means for relieving two supporting wheels 70 and 72 from the weight of bulkhead 24, when the bulkhead is in a stationary position. The carriage 50 also includes a bearing plate 58 that functions to distribute the load of the bulkhead over a relatively large area of a track 80, thereby greatly decreasing the unit loading on the track. In addition, carriage 50 serves to anchor the bulkhead in various selected positions and includes mounting means for effecting alignment of the carriage with its respective track. As seen in FIGS. 4 and 5, each carriage 50 includes a carriage frame 52 that includes a side plate 54, bottom plate 56, and spaced reinforcing gussets 68. The frame 52 is mounted on an end plate 26 of the bulkhead by four bolts 122 which extend through vertical slots 120 in side plate 54 and into threaded engagement with a respective threaded hole 124. It will now be understood that each end of carriage frame 52 can be vertically adjusted independently, thereby permitting alignment of carriage frame 52 with its respective track. It should be mentioned that two axles 74 and 76 are mounted on each end of the bulkhead by extending each axle through holes in end plate 26 and axle mounting plate 75, which plates comprise part of the bulkhead frame structure. Since axles 74 and 76 extend through side plate 50 of carriage 50, the vertical slots 116 are provided in side plate 54 to permit the above mentioned vertical adjustment thereof. With reference to FIGS. 4 and 5, bearing plate 58 is mounted under bottom plate 56 by two threaded guide pins 102 and 103 which have their bases welded to the top of bearing plate 58 and which extend freely through holes 108 in bottom plate 56. Each guide pin 102 and 103 includes a compression spring 106 and retainer nut 104 which serve to bias bearing plate 58 upwardly and clear of track 80. With continued reference to FIGS. 4 and 5, each carriage 50 includes jacking means for lifting the carriage frame 54 and wheels 70 and 72 to upper positions wherein the wheels are clear of track 80 and wherein the bearing plates 58 engage track 80 and support the weight of the bulkhead. Such jacking means comprises two bolts 91 and 93 which are located at respective ends of carriage frame 54, with each bolt being in threaded engagement with a nut 94 welded to bottom plate 56. The tip 98 of each bolt extends freely through a hole in bottom plate 56 and into rotatable engagement with the bottom of a bearing recess 100. It should be mentioned that wheel clearance openings 60 and 62 are provided in bottom plate 56 and bearing plate 58, respectively, so as to permit engagement of wheels 70 and 72 with tracks 80. As is best seen in FIGS. 4 and 5, the carriage means 50 is locked in selected positions along track 80 by means of a tie-down bolt 112 that extends freely through slots 114 and 115 in base plate 56 and bearing plate 58, respectively. It should be mentioned that the spacing of tracks 80 will, as a practical matter, vary due to errors in fabrication and erection. Another problem is present when the bulkhead is being repositioned in that, if one side of the bulkhead is moved more than the other, then the guide plates 92, at diagonally opposite corners of the bulkhead, will be biased against the sides of their respective tracks 80. This causes binding of such diagonally opposite wheels, which will arrest movement of the bulkhead. It should also be mentioned that wheels 70 and 72 include central hub or bearing portions 128 formed of suitable bearing material and resilient rim portions or tires 130 formed of rubber, plastic or the like. Each wheel may also be provided with a fixed circular guide plate 92 mounted on the side of the rim portion and extended to engage the side of track 80. Also, each wheel is mounted freely on necked axle portion 86, so as to be laterally shiftable with respect to a shoulder 87 that is spaced from the side of bearing portion 128 to provide clearance 90 for self aligning movement of the wheel when the bulkhead is being moved and when the guide plate 92 encounters a misaligned portion of track 80. Since each wheel is free to move laterally along necked axle portion 86, due to clearance 90 between shoulder 87 and the side of the wheel, it will be understood that each wheel can adjust laterally for variations in alignment of their tracks 80 and thereby avoid binding engagement when the bulkhead is being moved. Clearance 90 between wheels 70-72 and their respective shoulders 87 serves an additional function in that such clearance 90 permits lateral shifting of the entire bulkhead 24 with respect to wheels 70-72 when the wheels are frictionally engaging the tracks 80. This feature eliminates the above mentioned canting problem which occurs when the bulkhead is being repositioned and one side of the bulkhead is moved more than the other side, as discussed above. It should also be mentioned that clearance 90 for lateral shifting of the wheels and bulkhead can be varied by repositioning nut 73 with respect to shoulder 87. Hence it will be understood that clearance 90 can be established by adjusting nut 73 to provide sufficient lateral movement of wheels 70 and 72 to accommodate the maximum and minimum track spacing that will encounter the particular track installation. Reference is next made to FIGS. 6 and 7 which illustrate a modified carriage means 50-A that differs from the carriage means 50 of FIGS. 4 and 5 in that front and rear guide rollers 160 and 162 are respectively mounted on opposite ends of modified carriage means 50-A. One of these guide rollers 160 is shown in the partial side view of FIG. 6 with the other guide roller 162 being of identical construction and mounted on the opposite end of the carriage. It should be pointed out that guide rollers 160 and 162 function as guide means for maintaining wheels 70-A and 72-A on their respective tracks 80, whereby the fixed circular guide plates 92 mounted on wheels 70 and 72 of the embodiment of FIGS. 4 and 5 are not required in the modified embodiment of FIGS. 6 and 7. Referring in detail to FIGS. 6 and 7, each of the guide rollers 160 and 162 is mounted on a respective end of a modified carriage bottom plate 56-A which includes roller mounting slots 163 formed through end extensions 150 on bottom plate 56-A. Each guide roller 160-162 is rotatably mounted on a threaded shaft 152 that is secured in hole 163 by mounting nuts 154 and 156. The modified embodiment of FIGS. 6 and 7 includes various identical structural components previously described above in the description of the embodiment of FIGS. 4 and 5, with such identical components being marked with identical numerals. In operation of the embodiment of FIGS. 6 and 7, it should be mentioned that the guide means provided by guide rollers 160 and 162 functions to prevent canting of the bulkhead during movement thereof. Such guide means also cooperate with the clearance spaces 90 provided at wheels 70-A and 72-A. Such clearance space 90 permits lateral shifting movement of bulkhead 24 with respect to wheels 70-A and 72-A, thereby precluding binding of wheel rotation. As a result, canting of bulkhead 24 is usually prevented from starting, and in instances where the canting tendency has started, it is relieved as movement of bulkhead 24 progresses. As a result, binding against rotation of the wheels is eliminated.	A bulkhead for use in a swimming pool that is moveable to selected positions along the length of the pool to divide the pool into various activity areas. The bulkhead includes supporting wheels mounted on tracks and is further characterized by jacking means for unloading the supporting wheels when the bulkhead is stationary.
You are an expert at summarizing long articles. Proceed to summarize the following text: STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon. BACKGROUND OF THE INVENTION The present invention relates to controlling fires, and, in particular, to oil well fires. The oil well fires of concern to the present invention are those that exist above the surface wherein the oil and/or gas is exiting from or near the wellhead that has been damaged. The present process used to extinguish oil well fires involves the application of continuous amounts of water in large volumes in the area about the source of the fire. This serves to cool any structures that could re-ignite the fire and allows personnel to approach the fire area to actually extinguish the fire using explosives. Of course, the oil and gas are still issuing from the well. The personnel must now enter this area and cap the wellhead. Although this process has worked in the past several disadvantages exist. For example, a large source of water must be near the wellhead. Also, the oil and gas may re-ignite. Another process for controlling the fire is to stop the flow of hydrocarbon fluids by drilling a second well bore adjacent to the problem well bore. The second well bore is slanted to closely meet the first well bore. A shaped charge can open up channels through which cement can be placed to stop the flow. U.S. Pat. No. 4,436,154 discloses such in a well having two payzones of highly different pressures. Where the pipe casing is easily reached, for example, at sea, a cryogenic control valve can be installed stop the flow and then direct the flow to another well head. The need to develop means for controlling oil well fires was documented in a New York Times article by William Broad as related to the oil well fires in Kuwait. It is noted therein that the problem is two fold: (1) putting the fire out and (2) capping the well. Some ideas advanced include putting 100 ton concrete caps on the burning well to stop the flames; using super cold foams; putting explosives collars on the pipes using implosion technology to seal the pipes; putting a cryogenic valve on the wellhead like the above patent. Thus, there is a need for a process to control oil well fires with a minimum of equipment and time. SUMMARY OF THE INVENTION The present invention involves processes to control oil well fires. The first process uses at least one standard bomb having an explosive charge placed thereon with an explosive cord (detonating cord) connected thereto. A detonator is connected to the explosive cord. The bomb is placed underground in a trench or a shaft augered in close proximity of the well pipe. Upon detonation, the force causes either partial or full closure of the well pipe without further damage. Two bombs may be physically placed such that they straddle the well pipe. The bomb may be air dropped or physically placed in position. In the other process, explosives are placed in augered shafts underground at inclined angles to the well pipe. These explosives accomplish several results: (1) They remove dirt to create a ramp for access to the well pipe; (2) they remove the cellar; and (3) they can crimp the well pipe. These explosives are physically placed in the proximity to the wellhead. These processes can be applied in the ground, water or air. Therefore, one object of the present invention is to provide a process for controlling oil well fires with high explosives placed in close proximity to the well pipe. Another object of the present invention is to provide a process to create a ramp and/or crater about the well pipe to allow access of people and equipment to the well pipe. Another object of the present invention is to provide a process of removing the cellar which may be impeding access to the well pipe. Another object of the present invention is to provide a process to create a ramp, remove the cellar and to crimp the well pipe in one operation. Another object of the present invention is to provide a process that minimizes equipment and time to stop oil well fires. Another object of the present invention is to provide a process to either partial close or fully close the oil well pipe. Another object of the present invention is to provide a process to remove casings to reach the inner oil bearing tube. These and many other objects and advantages of the present invention will be readily apparent to one skilled in the pertinent art from the following detailed description of a preferred embodiment of the invention and the related drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a typical oil well pipe in cross section. FIG. 2 illustrates a single bomb placed near to the oil well pipe. FIGS. 3A and 3B illustrate two bombs placed astride an oil well pipe. FIGS. 4A and 4B illustrate explosives astride an oil well pipe having a cellar assembly thereon. FIG. 5 illustrates placing the auger shaft near the well pipe. FIG. 6 illustrates a wellhead. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates a conventional oil well pipe 10 being approximately 20 inches in diameter having 5 concentric pipes 12, 14, 16, 18 and 20. The space 13 between pipes 12 and 14 is typically filled with a weak sand-cement mixture. During the testing of the present process, the annuli 22, 24 and 26 were filled with water and the inner pipe 20 was filled with a fluid material simulating oil having a density of about 0.25 grams/cc. This arrangement simulates a production oil well pipe. Referring to FIG. 6, a cellar 28 is typically placed on top of the well pipe 10 and a Christmas tree 40 is connected to the well pipe 10 in the cellar 28. Referring to FIG. 2, a standard bomb 30 such as a Mark 84, 2000 lbs., a Mark 82, 500 lbs., etc. is placed underground near the well pipe 10. Means for exploding the bomb 30 could include a charge placed in the fuse well, not shown, an explosive cord to the charge, and a detonator connected to the cord. A conventional power source causes the detonator to initiate. Several factors are determinative of the well pipe closure: the size of the bomb, the distance of the bomb from the well pipe, the orientation of the bomb to the well pipe, the number of bombs, the density of the soil about the well pipe, etc. The placement of the bomb 30 near the well pipe 10 can be accomplished by drilling a shaft 34. See FIG. 5. A conventional drilling rig 36 would be placed within about two hundred feet of the wellhead and the shaft 34 drilled at an angle of preferably 5 to 10 degrees from the horizontal. This shaft 34 could be augered to a point within a prescribed distance from the well pipe 10. A PVC pipe can be inserted into the shaft 34 for preventing collapse, for ease of the bomb 34 insertion, and for placement of high explosives therein as shown in FIGS. 4A and 4B. FIG. 2 illustrates a single bomb 30 placed about 10 feet underground at a slant angle to the pipe. The axis of the bomb is perpendicular to the well pipe axis. FIGS. 3A and 3B illustrate the use of two Mark 82 bombs 30 placed astride the well pipe 10 at the distances indicated. The bomb axes are slanted 10 degrees toward the well pipe axis. FIGS. 4A and 4B illustrate the use of high explosives 32 such as ammonium nitrate fuel oil (ANFO) or other commercially available explosives to crimp well pipe 10, remove the cellar assembly 28 and produce an earthen ramp to the wellhead area. In these Figures, 2 PVC pipes 38 are filled with ANFO explosives. The shafts 34 are drilled at appropriate angles and distances and the PCV pipes 38 and explosives 32 are placed therein. Similar detonation techniques are used as in the above. The testing of the FIG. 3 configuration had pairs of Mark 82 bombs 30 straddling the well pipe 10 at distances of 1.5 feet, 0.5 feet and touching the well pipe. The rear fuse well was packed with 11/2 pounds of C-4 explosive material and fired with a double 54 grain prima cord from a RP 83 detonator. The greatest degree of closure occurred when the bombs were put in contact with the exterior pipe casing. Other tests at different stand-off distances resulted in 95% to 99% closure without cracking the casings. The testing of the FIG. 4 configuration indicated that at a distance of 3 feet from a well pipe filled with fluid the pipe would be closed. The above processes may be used in a water environment to crimp the well pipes. For excavation purposes, the detonation of either explosives or bombs in the slant holes results in a crater about 15 feet deep and 40 feet across. The well pipe casings is exposed and undamaged. The cellar and other debris is blown away. The tree also remains on top of the well casing. For crimping the well pipe, the explosives or bombs are placed closer. Unless placed in direct contact, the crimps only partially block the flow of oil and/or gas. If the casing is not crimped during the excavation, it can be done afterwards. Once crimped, the pipe can be capped after the fire is stopped. Once the well pipe is exposed, the casing layers can be removed with shaped charges allowing access to the inner tube which can be tapped or cut or sealed. Clearly, many modifications and variations of the present invention are possible in light of the above teachings and it is therefore understood, that within the inventive scope of the inventive concept, the invention may be practiced otherwise than specifically claimed.	Conventional bombs or commercially available explosives are selectively placed about well pipes and exploded to cause closure of the well pipe and thus resulting in substantial reduction in the flow of oil and gas to facilitate extinguishing the fire thereon. Explosive charges are selectively placed about the well pipes in slanting holes so to remove the cellar assembly, make a ramp to the well pipe, and to close the well pipe.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION Deepwater blowout preventer systems are major pieces of capital equipment landed on the ocean floor in order to provide pressure protection while drilling holes deep into the earth for the production of oil and gas. The typical blowout preventer stacks have an 18-¾″ bore and are usually of 10,000 psi working pressure. The blowout preventer stack assembly weighs in the range of five to eight hundred thousand pounds. It is typically divided into a lower blowout preventer stack and a lower marine riser package. The lower blowout preventer stack includes a connector for connecting to the wellhead at the bottom and several individual ram type blowout preventer assemblies, which will close on various pipe sizes and in some cases, will close on an open hole with what is called blind rams. Characteristically there is an annular preventer at the top, which will close on any pipe size or close on the open hole. The lower marine riser package typically includes a connector at the bottom for connecting to the lower blowout preventer stack, a single angular preventer for closing off on any piece of pipe or the open hole, a flex joint, and a connection to a riser pipe which extends to the surface to the drilling vessel. The purpose of the separation between the lower blowout preventer stack and the lower marine riser package is that the annular blowout preventer on the lower marine riser package is the preferred assembly to be used. When it is used and either has a failure or is worn out, it can be released and retrieved to the surface for servicing while the lower blowout preventer stack maintains pressure competency on the wellhead. The riser pipe going to the surface is typically a 21″ O.D. pipe with a bore larger than the bore of the blowout preventer stack. It is a low pressure pipe and will control the mud flow which is coming from the well up to the rig floor, but will not contain the 10,000-15,000 psi that the blowout preventer stack will contain. Whenever the high pressures must be communicated back to the surface for well control procedures, smaller pipes on each side of the drilling riser, called the choke line and the kill lines provide this function. These will typically have the same working pressure as the blowout preventer stack and rather than have an 18-¾-20″ bore, they will have a 3-4″ bore. These pipes come down on each side of the drilling riser, go past flex joints, to an area on each side of the connector connecting the lowering riser package to the lower blowout preventer stack. At this point they are connected to pipes which go down the lower blowout preventer stack and enter the bore of the lower blowout preventer stack, near the bottom of the blowout preventer stack. One of these lines is called the choke line, and has a general job description of allowing high pressure well fluids to flow up across chokes during the well control operations. The line on the opposite side is typically called the kill line and it is attached below the lowest blowout preventer ram and has a general job description of communicating a heavy fluid to be pumped down into the well to kill the well. Killing the well means that the pressure in the formation is high enough to overcome the pressure head of the fluid in the bore. Killing the well is placing heavy enough fluid in the well bore to overcome the formation pressures. When the lower marine riser package is disconnected from the lower blowout preventer stack, the choke and kill lines must be disconnected. There are typically two types of connectors for this application, a passive connector and an active connector. The passive connector is typically a straight stab and would typically have a seal O.D. of about 4-½″. As the stab is on about a 5 ft. radius from the centerline of the blowout preventer stack, if one of these units is pressured to 10,000 psi it exerts a force of approximately 160,000 lbs. on the blowout preventer stack or puts a moment of approximately 800,000 ft. lbs moment on the blowout preventer stack connector. This is a substantial force to be withstood and requires a redesign and reinforcement of the blowout preventer stack to accommodate these high forces. The connector type choke and kill connector literally engages a small connector similar to the one that is on the centerline of the blowout preventer stack. By having an actual connector on the choke or kill connector the pressure force is taken within the connector and eliminates the destructive moment forces on the blowout preventer stack frame. A problem can occur in this design in that when the connector must be released in an emergency situation such as when the vessel has lost control and is being driven off location on the surface, the connector may not release. If the connector does not release in a drive off situation, the unit will be torn in half causing substantial damage to the blowout preventer stack, making it expensive and difficult to recover. Literally if a connector does not release and the blowout preventer stack is released, the recovery and repair is a multi-million dollar repair operation. An additional problem with conventional choke and kill connectors is that the choke and the kill lines are a pipe as long as 12,000 feet back to the surface, full of expensive drilling mud. When the open marine riser is released and the connector is released, the entire column of mud is spilled onto the ocean floor, representing not only a high cost but pollution potential. The conventional solution to this is the addition of a high pressure failsafe gate valve on the choke line and the kill line, along with additional required control functions for the valve. SUMMARY OF THE INVENTION The object of this invention is to provide a connector which is a passive connector which does not lock onto the lower mandrel, but also does not provide a separation force to be sustained by the blowout preventer guide frame and lower marine riser hydraulic connector. A second object of the present invention is to provide a means for integral valving to retain the drilling mud in the choke and kill lines. A third object of the present invention is to provide redundant re-energizeable sealing. Another object of the present invention is to provide a connector which is tolerant of real-world manufacturing and installation conditions. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of a complete system for drilling subsea wells. FIG. 2 is a closer view of a subsea blowout preventer stack showing the installation of a connector of this invention. FIG. 3 is a cross section view of a connector of this invention in the operating condition. FIG. 4 is a top view of the connector of this invention. FIG. 5 is a cross section view of the connector of this invention with the valving closed. FIG. 6 is a cross section view of the connector of this invention with the valving closed and the upper section separated from the lower section. FIG. 7 is a close-up cross section of the lower end of the internal valving of this invention showing the angular misalignment capability. FIG. 8 is a cross section view of an alternate embodiment of the connector. DESCRIPTION OF THE PREFERRED EMBODIMENT Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort, even if complex and time-consuming, would be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. Referring now to FIG. 1, a view of a complete system for drilling subsea wells 1 is shown in order to illustrate the utility of the present invention. The C&K connector 3 is shown at approximately the same elevation as the interface 5 between the lower Blowout Preventer stack 7 and the lower marine riser package 9 . The lower marine riser package 9 sits generally on a subsea wellhead system 11 , which in turn is landed on the ocean floor 13 . Below the subsea wellhead system 11 , it can be seen that a hole was drilled for a first casing string, that string 15 was landed and cemented in place, a hole drill thru the first string for a second string, the second string 17 cemented in place, and a hole is being drilled for a third casing string by drill bit 19 on drill string 21 . The lower Blowout Preventer stack generally comprises a lower hydraulic connector for connecting to the subsea wellhead system 11 , usually 4 or 5 ram style Blowout Preventers, an annular preventer, and an upper mandrel for connection by the connector on the lower marine riser package. The C&K connector 3 is on a vertical pipe 30 which is generally illustrative of a choke or a kill line. Typically the kill line will enter the bore of the Blowout Preventers below the lowest ram and has the general function of pumping heavy fluid in the well to overburden the pressure in the bore or to “kill” the pressure. The general implication of this is that the heavier mud will not be circulated, but rather forced into the formations. The choke line will typically enter the well bore above the lowest ram and is generally intended to allow circulation to circulate heavier mud into the well to regain pressure control of the well. The circulation path will be discussed following. For brevity of space, the line 30 is intended to be exemplary of both the choke and kill lines. Generally a choke valve is indicated at 32 and a kill valve indicated at 34 . Normal drilling circulation is the mud pumps 40 taking drilling mud 42 from tank 44 . The drilling mud will be pumped up a standpipe 46 and down the upper end 48 of the drill pipe 21 . It will be pumped down the drill pipe 21 , out the drill bit 19 , up the annular area 50 between the outside of the drill pipe 21 and the bore of the hole being drilled, up the bore of the casing 17 , thru the subsea wellhead system 11 , the lower Blowout Preventer stack 7 , the lower marine riser package 9 , up the drilling riser 52 , out a bell nipple 54 and back into the mud tank 44 . During situations in which an abnormally high pressure from the formation has entered the well bore, the thin walled drilling riser 52 is typically not able to withstand the pressures involved. Rather than making the wall thickness of the relatively large bore drilling riser thick enough to withstand the pressure, the flow is diverted to a choke line 30 . It is more economic to have a relatively thick wall in a small pipe to withstand the higher pressures than to have the proportionately thick wall in the large riser pipe. When the higher pressures are to be contained, one of the annular or ram Blowout Preventers are closed around the drill pipe and the flow coming up the annular area around the drill pipe is diverted out thru choke valve 30 into the pipe 30 . The flow passes up thru C&K connector 3 , up pipe 60 which is attached to the outer diameter of the riser 52 , thru choking means illustrated at 62 , and back into the mud tanks. The connector illustrated in the figure is a passive stab connector and as discussed previously, it is simply a stab sub which produces a separation force upon pressuring which is a function of the seal diameter and the pressure. It in turn produces a moment on the structures and lower marine riser connector which is a function of the force and the distance from the centerline of the lower marine riser connector. The connector of this invention will be discussed in further detail in the figures which follow. On the opposite side of the drilling riser 52 is shown a cable or hose 70 coming across a sheave 72 from a reel 74 on the vessel 76 . The cable 70 is shown characteristically entering the top of the lower marine riser package. These cables typically carry hydraulic, electrical, multiplex electrical, or fiber optic signals. Typically there are at least 2 of these systems, which are characteristically painted yellow and blue. As the cables or hoses 70 enter the top of the lower marine riser package 9 , they typically enter the top of control pod to deliver their supply or signals. When hydraulic supply is delivered, a series of accumulators are located on the lower marine riser package 9 or the lower Blowout Preventer stack 7 to store hydraulic fluid under pressure until needed. Referring now to FIG. 2, a closer view of a subsea blowout preventer stack shows the installation of a connector of this invention. The C&K connector 3 is shown at the interface 5 between the lower marine riser package 9 and the lower Blowout Preventer stack 7 . The lower Blowout Preventer stack 7 shows the lower hydraulic connector 80 , four ram Blowout Preventers 82 - 85 , and an annular Blowout Preventer 86 . The lower marine riser package 9 shows a hydraulic connector 90 for engaging a mandrel on the lower Blowout Preventer stack, an annular Blowout Preventer 92 , a flex joint 94 , drilling riser section 96 , choke line 98 , kill line 100 , choke or kill line flex pipe 102 and control pod 104 . Valve 106 is a remotely controlled failsafe gate valve which conventionally has the job of being closed to allow testing of the choke or the kill line during running as joints are added, and to save the mud in the choke or the kill line after disconnection. This valve which is required by alternate connectors is eliminated by the connector of this invention. Referring now to FIG. 3, cross section view of a connector of this invention is shown in the operating condition. Plate 110 is the lower structural plate of the lower marine riser package and plate 112 is the upper structural plate of the lower Blowout Preventer stack. Mandrel 114 is bolted to plate 112 with bolts 116 , has a central bore 118 and an outlet bore 120 at an angle with respect to the central bore 118 . In the case of the illustration the angle is 30°. Upper body 130 has a central bore 132 which is generally aligned with central bore 118 and an outlet bore 134 at an angle to the central bore 132 . The upper body 130 is bolted to plate 110 with bolts 136 . Shims 138 are provided to give angular alignment adjustment capability for upper body 130 with respect to mandrel 114 . Slide member 140 is provided with a flow path 142 at an angle such that it communicates the bore 120 with the bore 134 . Slide member 140 has seals 144 , 146 , 148 , and 150 such that seals 144 and 146 seal the interface between flow path 142 and bore 120 and seals 148 and 150 seal the interface between flow path 142 and bore 134 . As seals 144 and 146 are circular, concentric, and of the same seal diameter, they do not provide an axial force but rather are pressure balanced. In the same manner, as seals 148 and 150 are circular, concentric, and of the same seal diameter, they do not provide an axial force but rather are pressure balanced. As can be seen in the figure, flow enters the flange 160 ; flows along the path of arrows 162 , 164 , 166 , and 168 ; and then flows out of flange 170 . Cylinder 172 at the top of the assembly along with piston 174 hold the slide member 140 in the correct position for communication. Referring now to FIG. 4, a top view of the connector of this invention is shown landed on plate 110 . Referring now to FIG. 5, a cross section view is shown of the connector of this invention with the valving closed. Seals 144 and 146 are in approximately the same position as seals 148 and 150 were in FIG. 3, causing both ends of the flow path 142 to be sealed against central bore 132 . The effect of this is that the flow into or out of bore 134 is sealed off, with the slide member 140 acting as a shutoff valve. Referring now to FIG. 6, a cross section view of the connector of this invention with the valving closed and the upper section separated from the lower section as it would be when landing the lower marine riser package on the lower Blowout Preventer stack or removing the lower marine riser package from the lower Blowout Preventer stack. When engaging, the diameter 180 on the mandrel 114 first engages diameter 182 of upper body 130 to provide concentricity alignment between the mandrel and the upper body. This diametrical engagement ensures that the diameter indicated at 184 which will be sealed by seals 146 is closely aligned with the bore 132 of the upper body 130 . Seal area 186 of mandrel 114 is further from the engagement of the aligning diameters 180 and 182 and is therefore more subject to angular misalignment. Referring now to FIG. 7, a close up cross section of the lower end of the internal valving of this invention is shown with the angular misalignment compensation capability. Seal 144 is actually made up of triple seals 190 , 192 , and 194 on ring 196 . The seals are preferably of a resilient compound for ease of reliable sealing against a straight bore, and are preferably of a metal seal to prevent blowing off when the slide member is opened with pressure in the bore. Ring 196 is fitted with an additional face seal 198 which engages a flat face 200 on retainer 202 . Retainer 202 is a portion of slide member 140 which is releasably attached to the lower end. Gap 204 around diameter 206 allows the ring 196 to float radially to compensate for angular misalignment of the central bore 118 with the bore 132 and still remain in a sealing relationship with the other parts of slide member 140 . Referring now to FIG. 8, a reversal of parts is shown with the slide member 220 being the outer cylindrical member rather than the inner bar type member. The flow path is curved to allow the bar type upper and lower members to be fluidly connected. The cylinder 222 would be two cylinders on each side of the assembly. Multiple check valves are shown at 224 to indicate that sealant can be injected into the space between the multiple seals in case full sealing is not obtained naturally. In deep water operations, the sealant can be injected by a remotely operated vehicle (ROV). The same ports can be used as test ports when the unit is first engaged. The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.	A choke or kill line connector for a subsea blowout preventer stack which is slide member operated to provide pressure balanced design to eliminate the potentially high forces associated with connectors which do not have the complication of a locking connector and provide integral valving capability to allow for testing and to retain drilling mud in the choke or kill lines upon disconnection.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION The present invention resides in the field of metal fascia dimensioned and configured to overlie the roof edge of a built-up or flat roof. The apparatus may be described as a base plate having a shorter portion for lying atop the roof edge and a longer portion at right angles to the first portion for overlying the upper sidewall and being attached thereto by the use of threaded fasteners through a series of holes perforating the longer portion. A cover fascia plate is attached to flanges at the upper and lower portions of the base plate and held at tension upward and outward from the base plate by a spring clip uniquely positioned between the base plate and the fascia cover. Large rubber membranes and the like are commonly used for covering a roof such as a flat roof. The membrane is laid over the surface of the roof and secured in place by adhesive and/or mechanical fastening means. A number of prior mechanisms have been developed for securing the edges of a rubber roof membrane in place along the edge of the roof in order to maintain the roofing membrane in position in proximate contact with the underlying roofing support surface. In some applications the rubber membrane may be subjected to significant wind forces causing the rubber membrane to tend to pull away from the surface of the roof. The edge of the roof is especially susceptible to damage from wind shear forces, and, if the edge of a rubber roof membrane were to become detached from the roof, all or a substantial portion of the membrane may be blown off. Moreover, damage often occurs from water entering the building structure, for example by flowing over the edge of the roof and down an outside wall where it may enter the structure and cause damage to the building. Generally, an upwardly extending water dam is mounted at the edge of the roof and a fascia is mounted over the water dam. The fascia generally also extends downward, parallel to the outside wall of the building. The fascia improves the appearance of the roof edge and further increases resistance to wind-driven rain and wind uplift loads along the roof edge. Unfortunately, existing systems often require non-standard water dams and/or edge fascia which are comprised of a number of complicated parts that are difficult and time consuming to install. One generally accepted roof edge systems are described in U.S. Pat. Nos. 6,912,814 and 7,451,572 [Inzeo, et al.] that shows a roof edge clamping system for overlying the roofing membrane, clamping it down and providing a metal fascia at the roof edge to hide the bolts and plates of the clamping members. This system relies entirely upon fasteners to retain the cover in position and does not protect for the vertical penetration of water behind the fascia. Another system, one that utilizes a type of spring clip to force the roof edge metal fascia upward, is described in U.S. Pat. No. 6,578,322 [Kintop]. This system requires both a catch and the spring clip to operate properly and maintain the fascia in the required position. This system is complex to manufacture and just as complex to install on a rooftop. Based upon the number of metal plates, the required bends and folds, and the interrelationships of the various plates and folds, the complex system requires particular attention to positioning on installation. The cover overlying the fastener holding the spring clip in place suffers from the probability of releasing from wind shear along the roof surface without another fastener holding it in position. Still another edge fascia system using a spring clip is described in U.S. Pat. No. 5,927,023 [Kittilstad]. The Kittilstad system also depends upon a spring clip positioned between the top outward facing corner of the cover and a ridge formed along the inner rear side of the base over which the outer cover plate also fits. This system is subject to probable failure in the event that there is sufficient wind lift and the cover plate lifts away from the base plate ridge or if the cover plate is subjected to sufficient distortion due to damage or careless placement of ladders or walking along the roof edge. The two roof edge systems using the spring clip both rely upon the cover plate fitting over and holding the spring clip in place. However, the cover plate is not held down and is the second piece of metal curling around or over a raised portion of the base plate that is the sole retaining mechanism for the cover along the entire expanse of the roof edge system. This type of system suffers from the deficiencies noted above with neither system taking full advantage of a spring clip that force the cover plate away from the base plate when fully assembled. It is, therefore, an object of the present invention to overcome the previous deficiencies by using a differently positioned spring clip that forces the parts of the roof edge system away from each other, and then retains those parts in that orientation. It is a further object of the present invention to reduce the required time to install the spring clip type roof edge systems by housing the spring clip in a different fold or retaining space that that over which the cover plate is placed. It is yet an additional object to provide a spring clip that produces sufficient upward force to retain the top outer edge of the cover at its farthest outward and upward extent at all times, once fully installed. It is a still further object of the present invention to reduce the time and complexity of installation of the roof edge fascia system through the reconfiguring of the attachment points for the spring clip and cover plate. Other objects will appear hereinafter. SUMMARY OF THE INVENTION The present invention provides a superior roof edge fascia system for securing the periphery of a membrane to the edge of a roof so that the membrane remains securely fastened to and against the surface of the roof and will not pull up as a result of wind forces on the membrane. Specifically, the present invention provides a base plate having a shorter portion for lying atop the roof edge and a longer portion at right angles to the first portion for overlying the upper sidewall and being attached thereto by the use of threaded fasteners through a series of holes perforating the longer portion. The shorter portion of the base plate has, at its distal end, a pocket formed from overfolding the edge of the distal end at the uppermost region of an upstanding end portion of the base plate creating an upwardly distanced spacing away from the roofing system. The pocket is formed by the overlying of the edge turned inward and against the inner upper wall of the pocket, but only partially along the pocket depth. The pocket is dimensioned to receive a spring clip that is specially bent or folded at desired spacings so as to fit within the pocket and extend outward and upward to contact the inner side of the fascia cover plate at the approximate 90° fold point at the juncture of the horizontal and vertical legs of the cover supporting it in general parallelity to the base plate in both dimensional directions. At the distal end of the longer portion of the base plate an outwardly angled edge is formed for attaching the other end of the cover plate. The cover plate is dimensioned slightly larger than the base plate with a 90° bend between its shorter and longer portions approximating the same lengths from the bend in the base plate for each of the portions of the cover plate. The cover plate is held in position by bent edges that overlie the lower outwardly angled edge of the base plate and the inward facing edge of the pocket at the distal edge of the shorter portion of the base plate and supported in position by the properly positioned and located spring clip mounted within the pocket. Within the open space created by the pocket located at the shorter end edge of the base plate, and in order to maintain tension between the base and cover plates when mounted by exerting a force upward and outward from the 90° bend in the base plate to retain the cover plate in an extended support relationship, a plurality of spring clips are placed at predetermined locations along the extent of the fascia cover and base plates. The spring clip is formed in a relaxed S-shape with an elongated lower end extending and pushing into the formed pocket in the space remaining in the pocket depth beyond the reinforcing overfold of the end edge. The elongated lower end of the spring clip has a series of partial punched outward extensions such that as the end is inserted into the pocket of the base plate the spring clip is retained in position within the pocket so that it will extend forward, upward and outward to provide support for the interior of the bend in the cover plate. The spring clip, at its first bend, leaves the pocket and extends downward to the top of the base plate contacting the base plate approximately midway along the shorter portion. A second bend extends the spring clip upward toward the interior of the cover plate, but short of the inner side of the cover a reinforcing bend extends the spring clip outward toward the corner of the cover plate. A fourth bend in the spring clip contacts the interior of the cover plate at approximately an equidistant point on either side of the 90° bend to the distal end of the spring clip on the other side of the 90° bend. The spread of the two contact points add strength by providing a greater space between contact points and the contact point of the spring clip against the top side of the base plate provides a more stable support for the cover fascia corner while remaining unmovingly anchored in the pocket. The cover plate is mounted over the base plate and spring clip by engaging its lower portion bent edge over the lower portion outward angled edge of the base plate and then pushing the spring clip rearward into the pocket of the base plate the second bent edge of the cover plate is engaged with the upward angled edge of the base plate by slipping the edges over one another compressing the spring clip, and then permitting the spring clip to expand and force the cover plate outward away from the base plate retaining both edges in engagement. The foregoing and other features of the invention are hereinafter fully described and particularly pointed out in the claims, the following description and drawings setting forth by way of illustration and example the preferred embodiments of this invention. BRIEF DESCRIPTION OF THE DRAWINGS For the purpose of illustrating the invention, there is shown in the drawings forms which are presently preferred; it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. FIG. 1 is a perspective partial cutaway view of the fascia assembly of the present invention showing the S-shaped spring clip for maintaining an outward extension force against the fascia cover plate. FIG. 2 is a cross-sectional view of the fascia assembly of the present invention showing the functional interrelationship of the bottom plate, cover plate and spring clip. FIG. 3 is an isometric view of a plurality of spring clips for use with the present invention arrayed in a side-by-side alignment. FIG. 4 is a front view of the fascia assembly of the present invention at the roofline showing the approximate spacings of the plurality of spring clips for use along a length of overlapping fascia cover plates. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description is of the best presently contemplated mode of carrying out the invention. The description is not intended in a limiting sense, and is made solely for the purpose of illustrating the general principles of the invention. The various features and advantages of the present invention may be more readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings. With reference now to the drawing figures in which like-reference numerals designate like parts throughout the disclosure, the fascia assembly system of the present invention is illustrated generally at 10 in FIG. 1 having an S-shaped spring clip 12 for maintaining an outward extension force against a cover plate 14 . The system 10 is secured to a building having a number of sidewalls and a roof. The system 10 is designed to be secured to the building at the intersection or joining of the wall 11 and the roof, including roofing membrane 13 , in order to provide a superior fascia system for securing the periphery of the membrane 13 to the edge of a roof, along the upper expanse of the wall 11 , so that the membrane 13 is securely fastened to and against the surface of the roof and will not pull up as a result of wind forces on the membrane 13 . Referring to FIG. 2 , the fascia assembly 10 creates a functional interrelationship between and among a base plate 16 , the cover plate 14 and spring clip 12 . The base plate 16 is bent at right angles such that there results a shorter portion 19 a for lying atop the roof edge and a longer portion 19 b at right angles to the shorter portion 19 a for overlying the upper portion of the sidewall 11 . The longer portion 19 b of the base plate 16 is attached to the upper portion of the wall 11 by the use of threaded fasteners 17 through a series of holes perforating the longer portion 19 b and extending into the top portion of the wall 11 . As shown in FIG. 2 , the top portion of the wall 11 consists of a cover plate 15 made of lumber such that the fasteners 17 extend through the base plate 16 and into the wooden cover plate 15 at the top of wall 11 . Other materials can be used to cap the vertical wall 11 , and the type of fasteners used would be selected to mount the base plate 16 to the material used at the top of the sidewall 11 . The shorter portion 19 a of the base plate 16 has, at its distal end, an upwardly extending flange 20 with a horizontally oriented pocket 21 at its uppermost extent. In the example shown, the pocket 21 is positioned entirely inward away from the wall 11 , but the pocket 21 may be made to be closer to the wall 11 so long as there remains an inward facing bend 23 over which the cover plate 14 can be placed. The pocket 21 is formed by bending the upward extending flange 20 such that a lower first section extends away from the junction of the shorter and longer portions 19 a , 19 b , respectively, of the base plate at the 90° bend 19 c . The flange is then folded back over itself to form equal length portions with the inward edge of the overfolded section forming an edge within the pocket 21 . The overfolded edge extends partway back into the fold as both a reinforcement against the expansion of the pocket 21 and to serve as a block against the easy removal of the spring clip 12 once inserted into the pocket 21 . The pocket 21 is finally formed by folding the reinforced edge downward over the lower section with the pocket opening facing toward the base plate junction 19 c . In this manner the pocket 21 is formed by folding the inward facing edge of the base plate 16 and creating an upward spacing by means of flange 20 away from the shorter portion 19 a of the base plate and the membrane 13 of the roofing system to create a separation for the spring clip 12 of the present edge fascia system and to accommodate a location for the attachment of cover plate 14 . The pocket 21 is dimensioned to receive the spring clip 12 that is specially bent or folded at desired spacings, to be described more fully below, so as to fit within the pocket and extend outward and upward to contact the inner side of the fascia cover plate 14 at the approximate 90° fold point at the juncture of the horizontal and vertical legs of the cover plate 14 supporting it in general parallelity to the base plate 16 in both horizontal and vertical dimensional directions. In this way the properly positioned and located spring clip 12 , with one end mounted within the pocket 21 , retains the cover plate 14 in position away from the base plate 16 as described more fully below. At the distal end of the longer portion 19 b of the base plate 16 an outwardly angled edge 23 is formed for attaching the lower end 24 of the cover plate 14 . The cover plate 14 is dimensioned slightly larger than the base plate 16 with a 90° bend between its shorter and longer portions approximating the same lengths from the bend in the base plate 16 for each of the portions of the cover plate 14 . The cover plate is held in position by bent edges 24 , 26 that overlie the lower outwardly angled edge 23 of the base plate 16 and the rearward facing bend 25 of the pocket 21 at the distal edge of the shorter portion 19 a of the base plate 16 , respectively. The bent edge 26 of the cover plate 14 has sufficient length to extend completely over the bend 25 and extend farther downward toward the roof membrane 13 within the space afforded outside the flange 20 . Within the open space that is created the cover plate 14 and the base plate 16 , and in order to maintain tension between the cover and base plates 14 , 16 when mounted by exerting a force upward and outward from the 90° bend in the base plate 19 c to retain the cover plate 14 in an extended support relationship, a plurality of spring clips 12 are placed at predetermined locations along the extent of the fascia cover and base plates 14 , 16 . The spring clip 12 is formed in a relaxed S-shape with an elongated first end 30 extending and pushing into the formed pocket 21 in the space remaining in the pocket depth beyond the reinforcing overfold of the end edge. The elongated first end 30 of the spring clip 12 has a series of partial punched outward extensions 28 such that as the end of the spring clip 12 is inserted into the pocket 21 located at the distal end of the shorter portion 19 a of the base plate 16 the spring clip 12 is retained in position within the pocket 21 by the punched extensions 28 engaging the overfolded edge 29 of the pocket 21 . The engaging of the punched extensions 28 with the overfolded edge 29 locks the spring clip 12 in position so that it will extend forward, upward and outward to provide support for the interior of the corner bend of the cover plate 14 . With reference to FIG. 3 , the spring clip 12 , at its first bend 31 , leaves the pocket 21 and extends downward toward the base plate 16 , contacting the base plate 16 approximately midway along the shorter portion 19 a . A second bend 33 , acting as a fulcrum point, extends the spring clip 12 upward toward the interior of the cover plate 14 , but short of the inner side of the cover plate 14 a third or reinforcing bend 35 extends the spring clip 12 outward toward the interior of the corner bend of the cover plate 14 . A fourth bend 37 in the spring clip 12 contacts the interior of the cover plate 14 at approximately a point equidistant from the 90° corner bend of the cover plate 14 as the distal end 39 of the spring clip 12 on the other side of the 90° corner bend. The spread of the two contact points 37 , 39 of the spring clip 12 adds strength to the system by providing a greater space between the contact points of both the cover plate 14 and of the spring clip 12 . The fulcrum point bend 33 of the spring clip 12 contacting and pushing against the upward facing side of the base plate 16 provides a more stable support for the spring clip 12 providing the force required for retaining the cover plate 14 and fascia corner 14 c in a fully extended position while remaining unmovingly anchored in the pocket 21 . Referring again to FIGS. 1 and 2 , at the distal end of the longer portion 19 b of the base plate 16 is an outwardly angled edge 23 is located for attaching an inwardly angled end 24 of the cover plate 14 , which end of the cover plate 14 is angled similarly to, so as to mate with the outward angle of the distal edge 23 of the base plate 16 . The other end 26 of the cover plate 14 is also angled inwardly to overlie the inward extending exterior surface 25 of the pocket 21 at the upper end of the flange 20 along the distal edge of the shorter portion 19 a of the base plate 16 . The cover plate 14 is mounted over the base plate 16 and spring clip 12 by engaging the lower portion bent edge 24 of the cover plate 14 over the outwardly angled edge 23 of the lower portion 19 b of the base plate 16 and then compressing the spring clip 12 rearward toward the pocket 21 of the base plate 16 so that the second angled edge 26 of the cover plate 14 fits over and catches the rearward edge 25 of the exterior of the pocket 21 at the height of the flange 20 at the distal end of the shorter portion 19 a of the base plate 16 . The cover plate 14 is dimensioned slightly larger than the base plate 16 with a 90° bend between its shorter and longer portions 19 a , 19 b approximating the same lengths from the bend in the base plate 16 for each of the portions of the cover plate 14 . Within the space 18 created between the cover plate 14 and the base plate 16 the spring clip 12 extends as described above from the pocket 21 toward the fascia corner 14 c of the cover plate 14 exerting a force upward and outward from its fulcrum point 33 along the base plate 16 to retain the cover plate 14 in an extended tensioned spatial relationship. FIGS. 3 and 4 show a plurality of spring clips 12 , arrayed in side-by-side relationship, for use with the present invention. The rearward portions 30 of the spring clips 12 have a series of partially punched outwardly extending protrusions 28 such that as the end 30 of the spring clip 12 is inserted into the pocket 21 of the base plate 16 , the spring clip 12 is retained in position by the protrusions 28 extending upward beyond the edge 29 of the reinforcing fold of the pocket 21 so that the spring clips 12 cannot be easily withdrawn from the pocket 21 . Retained in this manner, the spring clip 12 will extend forward, upward and outward to provide support for the interior of the 90° bend at the outer corner 14 c of the cover plate 14 . Referring now to FIG. 4 there is shown the fascia assembly 10 at the roofline showing the approximate spacings of the plurality of spring clips 12 (in dashed lines) arrayed along a series of overlapping fascia cover plates 14 . The spring clips are positioned at the joints and at internal spacing to support the cover plates 14 at points where the outer integrity of the cover plates 14 in rejecting the penetration of moisture is critical, or to provide uniform support across the entire length of the cover plate 14 . In this manner both joints between fascia cover plates and the midpoints of the cover plates 14 are fully supported with the outward force of the spring clips 12 creating the outward tension force to retain the cover plates 14 in proper alignment for the edge fascia roofing system 10 to function as intended. The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, the described embodiments are to be considered in all respects as being illustrative and not restrictive, with the scope of the invention being indicated by the appended claims, rather than the foregoing detailed description, as indicating the scope of the invention as well as all modifications which may fall within a range of equivalency which are also intended to be embraced therein.	A combination fascia cover system is provided including a base plate having a shorter portion for lying atop the roof edge and a longer portion at right angles to the first portion for overlying the upper sidewall and being attached thereto by threaded fasteners through a series of holes perforating the longer portion. The shorter portion of the base plate having, at its distal end, an upwardly extending flange for creating an upward spacing away from the roofing system and at end of the flange a partially reinforced pocket is formed by overlying folds to form the pocket. The cover plate is mounted over the base plate with a spring clip having uniquely spaced bends configured to match the dimensions of the base and cover plates, which spring clip engages the pocket, the base plate and the cover plate to retain the base and cover plates in tensioned spaced relationship while engaged together with one another.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/908,933, filed Mar. 29, 2007. TECHNICAL FIELD The present invention relates to leaching chambers for receiving and dispersing water and wastewater when buried in the soil, and more particularly, to such pre-molded leaching chambers as are corrugated and arch-shaped in cross-section with contiguously molded end walls, and lateral interior chambers having fluid communication openings at the chamber base. BACKGROUND ART The use of above-ground watering systems, particularly in dry climates such as the southwestern regions of the United States and in the Mediterranean regions of Europe, the Middle East, and Africa, brings with it a list of known problems. In addition to water loss through evaporation during the watering process, if watering is provided too lightly, shallow plant rooting results. Additionally, repeated surface applications of water tend to produce the buildup of mineral salts, which are detrimental to healthy plant growth. As increasing population pressures result in greater demands upon fresh water supplies, the benefits of underground irrigation have become increasingly attractive. Such systems place water almost directly into the plant root zone and eliminate evaporative water losses. Their protected location also minimizes the risk of damage from surface activities. The subsurface fluid distribution system described in my previous patent, Sipaila, U.S. Pat. No. 5,921,711, provides such a subterranean system with reserve fluid storage capacity to maintain soil dampness as well as replace water taken up by plants. As used in a passive subsurface irrigation system, capillary physics and gravity are relied upon to deliver water and nutrients to plants through an interconnected series of chambers and pans. Such systems are capable of reducing the amount of irrigation water required by 50-80% over the more traditional above-ground systems. As is typical for such systems, the leaching chamber has sloped sidewalls that extend to a curved, arched top. When installed, such extended-arch chambers must resist both top and side loadings. The slots in the sidewalls permit the transport of water from within, but act to weaken the sidewall structure. While thickening the sidewall would provide additional strength, it also results in an increase in the amount of material required—which is a polyolefin, and is thus tied to the rising cost of petrochemicals. In addition, the added weight of the resulting product adds to the cost of transporting the chambers to the installation site. Also, while it is vital that such chambers are able to efficiently stack for transport, the stacking of such bulked-up chamber walls must not result in forcing the sidewalls out, resulting in the overall flattening and weakening of the arch-shaped chamber. It thus is desirable to provide additional solutions that increase the structural integrity of the arched chamber in a manner that enhances the operational efficiency and is not negated by increased transportation costs or product damage during shipment. DISCLOSURE OF THE INVENTION These and other objects are achieved by providing a pre-molded leaching chamber of arch-shaped cross-section, having a pair of contiguously molded, opposing end walls, alternating peak and valley corrugations along its length, and interior chambers formed at the base of the chamber at each peak corrugation providing fluid communication between the exterior and interior of the leaching chamber. The interior chambers are formed by an inner wall attached to an interior surface of the leaching chamber and extending substantially within the peak corrugation, spaced from the outer wall, to the base of the chamber. Vertically off-set apertures are formed in the inner wall and in the opposing outer wall, enabling fluid flow within the inner chamber. A leaching chamber comprising: a corrugated outer shell extending along a longitudinal axis in a manner defining alternating peak corrugations and valley corrugations, said corrugated outer shell having an arch-shaped cross-section with a pair of opposed lateral end walls formed therein and no floor; and a plurality of inner walls attached to an interior wall of said corrugated outer shell, each at a location within a separate interior valley formed in said interior wall, with each of said interior valleys corresponding to a peak corrugation formed in said outer shell, said plurality of inner walls extending from a location of attachment to said interior wall to a terminus of a respective one of said interior valleys, each of said plurality of inner walls extending in a manner inwardly spaced from said corrugated outer shell to define a plurality of interior chambers, wherein each of the plurality of interior chambers has an inner wall aperture formed in said respective inner wall and an outer shell aperture formed in the corrugated outer shell. A leaching chamber having an arch-shaped cross-section and alternating peak corrugations and valley corrugations along its length comprising: a pair of opposed end walls attached to said leaching chamber at opposite ends thereof, each of said pair of opposed end walls having a connecting pipe aperture formed therein; and a plurality of inner walls attached to an inner surface of said leaching chamber and extending towards a base of said leaching chamber, each of said plurality of inner walls extending in a spaced-apart manner from a separate one of such adjacent lateral wall segment of said leaching chamber as defines one of said alternating peak corrugations, each of said plurality of inner walls and each of said respective adjacent lateral wall segments define an individual interior chamber formed therebetween, each of said inner walls and said adjacent lateral wall segments have an aperture formed therein, whereby fluid communication between an interior of said leaching chamber and an outer environment of said leaching chamber may occur through each of said plurality of interior chambers. These and various other advantages and features of the present invention are pointed out with particularity in the claims. Reference should also be had to the drawings which form a further part hereof, as well as to the accompanying descriptive matter in which are illustrated and described in various examples of with the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial top perspective view of a leaching chamber in accordance with the present invention. FIG. 2 is a partial bottom perspective view of the leach chamber of FIG. 1 . FIG. 3 is a cross-sectional view, with portions shown in phantom, taken along line 3 - 3 of FIG. 1 . FIG. 4 is a partial cross-sectional view taken along line 4 - 4 of FIG. 1 . FIG. 5 is a partial cross-sectional view taken along line 5 - 5 of FIG. 1 . FIG. 6 is a partially exploded cross-sectional view of a plurality of stacked leaching chambers, the cross-sectional views of each of the chambers taken along line 3 - 3 of FIG. 1 . FIG. 7 is a partial cross-sectional view showing a connecting pipe enabling fluid communication between an adjacent pair of leaching chambers. FIG. 8 is a cross-sectional view, similar to FIG. 3 , with portions shown in phantom, taken along line 3 - 3 of FIG. 1 showing an alternative embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference is now made to the drawings wherein like numerals refer to like parts throughout. In FIG. 1 , a leaching chamber 10 includes a corrugated outer shell 14 and an end wall 18 . A connecting pipe aperture 22 is centrally located in the end wall 18 , and is appropriately sized to receive a connector pipe that extends between and is used to connect adjacent leaching chambers (not shown in the Figures). The end wall 18 also includes a pair of outer fluting extrusions 26 that are centrally located and extend between the connecting pipe aperture 22 and a base 24 of the end wall 18 . Functioning as stiffeners, the outer fluting extrusions 26 , together with a single inner fluting extrusion 28 (see FIG. 3 ), provide three-dimensional structural support to the end wall 18 without compromising the extrusion process of fabricating the leaching chamber 10 . Additional structural support is provided by a footing flange 32 that is attached to and extends from the base 24 of the end wall 18 . A plurality of triangular braces 34 are arranged in a spaced-apart manner along the footing flange 32 to provide lateral rigidity to the flat end wall 18 . Each of these end wall reinforcement features may be fabricated as part of the extrusion process used to form the end wall and corrugated outer shell of the leaching chamber 10 . A support footing 42 extends along each lateral terminus of the corrugated outer shell 14 , providing a stable support base when the leaching chamber 10 is positioned for use in an irrigation system or drainage system as well as when it is stacked for transport. In regard to the latter function, a stacking nub 46 is formed on and projects at a lateral location on the corrugated outer shell 14 . The stacking nubs 46 are positioned in a manner that provides support to the support footing 42 when a plurality of leaching chambers 10 are vertically stacked (see FIGS. 3 and 6 ). The corrugated outer shell 14 exhibits a repeating outer pattern of peak corrugations and valley corrugations (ridges and grooves), with these outer peaks and valleys inversely corresponding to peaks and valleys from a perspective within the leaching chamber 10 (see FIG. 2 ). An inner wall 52 is formed within each of the interior valleys, and extends from the support footing 42 to a fused attachment seam 54 formed in the corrugated outer shell 14 . The inner wall is inwardly spaced from the corrugated outer shell 14 at its location of attachment to the support footing 42 , forming an interior chamber 58 (see FIG. 4 ). A plurality of such interior chambers 58 are formed in, and laterally extend along, in a spaced-apart manner, both longitudinal sides of the leaching chamber 10 . Each of the interior chambers 58 is provided an inner wall aperture 62 formed in the inner wall 52 and an outer shell aperture 64 that is formed in the corrugated outer shell 14 . In a presently preferred embodiment, the inner wall aperture 62 and the outer shell aperture 64 are vertically off-set, with the outer shell aperture 64 at a vertical location that is lower than the inner wall aperture 62 when the leaching chamber 10 is in operation. As is best shown in FIG. 4 , this vertical off-set inhibits the reverse flow of particulate matter from the outer environment through the interior chamber 58 , which would otherwise result in the fouling of the primary chamber of the leaching chamber 10 . As discussed previously, most applications require a series of leaching chambers 10 that are connected together using discrete connecting pipes, with each pipe extending between opposing connecting pipe apertures to connect together adjoining leaching chambers 10 . It is essential that each leaching chamber 10 remain in fluid communication with any adjoining leaching chamber 10 with which it shares a connecting pipe 70 (see FIG. 7 ). As is depicted in both FIGS. 5 and 7 , a stop nub 68 is formed in an interior wall of the corrugated outer shell 14 and extends downwardly to provide a surface against which an end of the connecting pipe 70 can rest. The stop nub 68 resists any further inward migration of the connecting pipe 70 after installation. Such longitudinal movement—in either direction, could result in the dislodgement of the connecting pipe 70 from an adjoining leaching chamber 10 , which in turn would abruptly end or severely impair the fluid communication therebetween. The distance between the adjacent, connected leaching chambers 10 can be as short as a few inches or as long as ten feet, depending upon the particular application. Separation in typical athletic fields is about one foot between the end walls 18 . In an alternative embodiment of the present invention shown in FIG. 8 , the connecting pipe aperture 22 has been repositioned close to the base 24 of the end wall 18 . Under this embodiment drainage occurs at the bottom of the leaching chamber 10 , and no or only a very slight amount of water remains within the leaching chamber 10 —unlike the reservoir of water created within the leaching chamber 10 when the connecting pipe aperture 22 is positioned at a higher location on the end wall 18 (see FIG. 3 ). The embodiment of FIG. 8 is also provided a lower profile, having a preferred height A of 4 inches instead of 6.3 inches, and a width B of 8.25 inches instead of the previous 13.25 inches. These dimensions provide a reduced profile having less cost in material, the ability to be placed at a shallower depth and with less fill—both lowering installation costs. The remaining dimensions are preferably much the same as in the previously discussed embodiment, the connecting pipe aperture 22 having a diameter C of 2.375 inches, the inner wall aperture 62 having a height D of 0.875 inches, and the outer shell aperture 64 having a height E of 1 inch (preferably reduced by one-half inch as compared to the previously-discussed embodiment). The embodiment shown in FIG. 8 is best suited for applications in which drainage is the primary and/or only intended function. However, in flat arrays of the system, water backup can be obtained by utilizing an up-turned elbow as a terminating connecting pipe (not shown in the Figures). Such a terminus would create a pressure head, resulting in the flooding of the connector pipe and all intermediate leaching chambers—making irrigation a possible, but not preferred function of the alternative embodiment shown in FIG. 8 . In a presently preferred embodiment, and recognizing that other dimensions are possible—and considered within the scope of the present invention, the leaching chamber 10 is fabricated by extruding a plastic such as high density polyethylene, polypropylene or other suitable polymers. By positioning all of the offset and connecting apertures in an injection mold cavity, all of the improvements can be monolithically molded to produce a one-piece leaching chamber without any other machining. The inner wall apertures and the outer shell apertures are spaced approximately one-and-a-half inches apart, on center, and are vertically offset approximately 1 to 1½ inches. The ½ inch stacking nub 46 and ¼ diameter and ½ inch-long stop nub 68 ; the ¼ inch by 3 inch-long fluting extrusions, the 2 inch height of the inner wall 52 ; the 1 inch width of the footing flange 32 , the ½ inch triangular braces 34 , and the 1 inch wide support footing 42 can all be incorporated in the same injection mold process to produce a single piece integrated chamber. The installation of the leaching chambers in accordance with the present invention is initiated by the excavation of a series of trenches, fourteen to eighteen inches deep and eighteen to forty-eight inches wide. The length and width of the trenches will vary, depending upon the design requirements for the particular leaching bed, irrigation field or drainage tile. At a minimum, an excavated section of length four feet is leveled, and if downward leaching of water is not desired, water impermeable liners or enclosing boxes are installed in the leveled trench. Thereafter a series of leaching chambers are placed within the trench, and laid end-to-end so that the lateral leaching chamber water discharge apertures are substantially aligned. The leaching chambers are then connected to one another utilizing the end panel connector pipes. A layer of sand or suitable fine gravel for drainage applications is then back-filled over the leaching chambers. Since the upward capillary draw of most sands exceeds a ten-inch vertical above the waterline, a preferred depth of the fill sand over the leaching chambers is approximately twelve inches from the trench bed. The present invention can make use of sands of varying coarseness, with a sand coarseness of 0.3 mm to 0.6 mm grain size being viewed as particularly appropriate. Finally, the sand layer may be optionally covered with top soil to a depth of between approximately zero to four inches. Because of the arched cross-section of the outer shell 24 , the leaching chambers 10 are sufficiently strong to withstand the weight of vehicles on top of the replaced soil. Additionally, the individual settling of the leaching chambers within the trenches will not cause a break in the sand seal of the system, since the connector pipes 70 are self-adjusting with the apertures 22 in the end wall 18 . Depending upon the slope of the particular terrain, several different arrangements of the leaching chamber arrays are possible. Since the leaching chamber units act independently throughout their (preferred) four foot length, on sloping terrain the trenches are preferably excavated level along the slope contours. The “adjacent” leaching chambers can then be connected perpendicularly across the slope contours, with such adjacent leaching chambers located on different vertical levels, utilizing longer connector pipes where required. My invention has been disclosed in terms of a preferred embodiment thereof, which provides an improved half-pipe leaching chambers for subterranean fluid distribution that is of great novelty and utility. Various changes, modifications, and alterations in the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. It is intended that the present invention encompass such changes and modifications.	A leaching chamber having an arch-shaped cross-section, a pair of contiguously molded, opposing end walls, and alternating peak and valley corrugations along its length, is provided interior chambers and fluid communication openings along the base on each extending side of the chamber. Formed within the chamber at locations corresponding to each peak corrugation, an inner wall is attached to an interior surface and extends substantially within the peak corrugation to the base of the chamber. An aperture is formed in both the inner wall and in the opposing outer wall of the chamber, enabling fluid communication through the interior chamber—and thus into and out from the interior of the leaching chamber itself.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION In mounting gates on steel fences, particularly industrial fences, where the gates are long and heavy, it is necessary to adjust the hinge members so that the gate will fully open with a 180° swing. With the hinges presently in use, their construction prevents opening of the gate, in one direction, to much more than 90°, and where a long heavy gate is employed, it is very difficult to maintain the gate properly hung in horizontal alignment. It is an object of this invention to provide a gate hinge consisting of a male and female member that can be quickly and easily installed, adjusted and maintained in alignment. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of the hinges, showing the respective posts in dotted lines, and FIG. 2 is an exploded view of the parts of the respective hinges. DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, the numeral 1 designates a fence post, such as the tubular steel member employed in construction of steel fences, on which a male member 2 is mounted adjacent the top of the post, and another adjacent the bottom of the post, the male member 2 having elongated slots 3, 3 which receive the externally threaded ends of the U-bolt 4, and which are adapted to receive the nuts 14, 14, and a post gripping member 5 has a pair of integral arcuate jaws 6, 6 and a flat base 7 and bolts holes as 8 to receive the respective ends of the U-bolt 4. The male member 2 is bent at a right angle adjacent one end, and a post 17, extending vertically beyond the side of the body of the male member is integral with the end face of said bent end. The female member 9 has the slots 10, 10 and a post gripping member 11, constructed as above described for the member 5, through which the U-bolt 12 extends, the ends of the U-bolt 12 having external threads to receive the nuts 13, 13, the parts 12, 11 and 9 functioning in the same way as the parts 4, 5 and 2. The member 9 is bent at a right angle adjacent one end and has the tubular member 15 mounted on said end. When mounted on the gate post and the hinge post, before final tightening of the nuts 13, 14, the members are rotated on the respective posts until the pin 17 and socket 15 are in axial alignment, and in alignment with the center line of the respective posts, when the nuts 13, 14 are tightened to anchor the members to the posts. In hanging a gate, the male members 2, 2 are mounted on the fence post bordering the gate opening, and with the post 17 aligned with the center of the post 1, and the fence (not shown). The gripping member 5 is mounted on the U-bolt 4, with the arcuate jaws 6, 6 bearing against the post 1, and the threaded ends of the U-bolt extending through the elongated slots 3, 3, and the nuts 14, 14 mounted on said threaded ends and when the member 2 is laterally adjusted, the nuts are tightened to maintain the member 2 in position. The female member 9 is similarly mounted on the gate post 16 with the socket of the uppermost member receiving the lower end of the post 17 on the uppermost hinge member 2 and the socket of the lowermost member 9 receiving the upper end of the post 17 on the lowermost male hinge member. As may be seen, any lateral adjustment necessary to the gate may be readily made by loosening the nuts of either member, and sliding the member laterally within the slots 3 or 10. If desired, the respective male and female members may be constructed without the right angle bend, where an opening in one direction only is desired. This application is an improvement over the invention made the subject matter of a previous application for patent which has matured into U.S. Pat. No. 3,811,149.	A gate hinge for fences, particularly steel mesh fences, having means for mounting the gate post members and the fence post members in alignment with each other and which may be readily adjusted laterally without disconnecting the respective hinge members.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION 1. Field of The Invention The apparatus of the present invention relates to excavating buckets. More particularly the present invention relates to a detachable finishing blade which can be easily positioned on different size excavation buckets and allow for the finishing of broad areas excavated, and allow movement of a greater capacity of material into the bucket. 2. General Background In excavation of land utilizing a backhoe or the like apparatus, the backhoe is equipped with an excavation bucket, which in general comprises a bucket-shaped scoop mounted at the end of the arm of the backhoe, the bucket having a plurality of excavating teeth protruding from its bottom wall, so that it can excavate the land area, or the like, and move fill into the bucket for disposal, etc. Excavating buckets are also utilized to help complete an excavation project, following the filling of a ditch or pit, by smoothing out the dirt, packing it in, or scraping off the excess fill to flatten the area. One of the shortcomings of the state of the art excavation bucket is the inability of the bucket to be easily utilized on the finishing work following excavation. Usually, the bucket, or the teeth on the front of the bucket have to be replaced by a blade so that the blade can be utilized to form a smooth finished surface as the blade is moved along the ground in the finishing method. However, in the art, there is no system of excavation buckets which allows the easy adaptation of a typical excavation bucket by the attachment of a blade onto the front of the bucket, so that the bucket can be used to finish excavation and yet allow materials to continue to be loaded into the bucket following adaptation of the blade unit. The prior art which was found as a result of a patentability search is being submitted herewith as part of the Art Statement and is incorporated herein by reference thereto. Other objects of the invention will be obvious t those skilled in the art from the following description of the invention. SUMMARY OF THE PRESENT INVENTION The apparatus of the present invention solves the problems in the art in a simple and straight forward manner. What is provided is an improved excavating bucket, having a pair of sidewalls, a rear wall, a floor portion and an open front portion for receiving material thereinto; plurality of teeth members secured to the floor portion for digging into the material to be excavated; a finishing blade movably mounted to the bucket, the blade extending across a width greater than the width of the bucket opening, and having a forward edge for scraping; a raised channel formed on the upper face of the blade for engaging a plurality of the teeth members; sidewall members extending from the outer edges of the blade for engaging the wall of the bucket, for defining an uninterrupted travelling space for material into the bucket; and adjustable support sleeves positioned between the blade and the bucket sidewalls to stabilize the blade on the bucket. Therefore, it is a principal object of the present invention to provide an excavation bucket adapted with a finishing blade so that the bucket can be easily used to finish a job, and continue to function as an excavation bucket; It is a further object of the present invention to provide a finishing blade for an excavation bucket which can be secured to the teeth of the bucket, and held in place by adjustable sleeves to allow the bucket to function as a finishing tool; It is a further object of the present invention to provide a finishing blade system attachable to a standard excavation bucket, so that the blade can be removed easily, yet while in place held secure to undertake finishing jobs, and adjust to various size buckets; and It is a further object of the present invention to provide a system for mounting a finishing blade on an excavation bucket which provides for a swivel mounting feature so that the blade can be mounted on different size buckets. BRIEF DESCRIPTION OF THE DRAWINGS For a further understanding of the nature and objects of the present invention, reference should be had to the following detailed description taken in conjunction with the accompanying drawings, in which like parts are given like reference numerals, and wherein: FIG. 1 illustrates an overall view of the preferred embodiment of the present invention; FIG. 2 illustrates an overall top view of the preferred embodiment of the present invention; FIG. 3 illustrates an overall view of the preferred embodiment of the present invention during a finishing procedure; FIG. 4 illustrates an overall cutaway view of the mounting sleeve utilized in the preferred embodiment of the present invention; FIG. 5 illustrates an overall view of the mounting sleeve utilized in the preferred embodiment of the present invention; FIGS. 6A and 6B illustrate partial views of the mounting sleeves utilized in the preferred embodiment of the present invention; FIG. 7 illustrates a partial side view of the blade mounted onto an excavation bucket tooth member in the preferred embodiment of the present invention; FIG. 8 illustrates a partial view of the mounting rod showing further the swiveling of the rod mounted in place; FIG. 9 illustrates a partial view of the plate utilized for engaging the tooth members in the mounting of the blade; and FIG. 10 is a top view of the blade to be utilized in the preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 through 10 illustrated the preferred embodiment of the present invention by the numeral 10. As illustrated in overall view in FIG. 1, apparatus 10 comprises an excavating bucket 12, of the type having a pair of upright side walls, 14, 16, a curved base portion 18, which extends from a rear upright portion 20, to the floor 22 of the bucket. There is further provided an upper portion 24, for connectedly engaging the bucket 12 to the arms 26 of a backhoe (not illustrated) or the like implement to excavate earth or the like material. Further, the excavating bucket 12 includes a plurality of excavating teeth members 30, along the front edge 32 of the floor 22, with each of the teeth members extending therefrom, and spaced apart to form the plurality of digging means. Each tooth includes a body portion 34 secured through welding or the like to the front edge 32 of floor 22, and terminate in a beveled edge 36 to form a point 38 that excavates the earth. The bucket as illustrated in FIG. 1 also defines a space 40, formed by the floor portion, and side walls, wherein materials excavated are moved into for clearing out the area. As further illustrated in FIG. 1 in overall view is the means for transforming the excavating bucket 12 to a finishing implement, of the type to spread the upper level of dirt into a smooth layer, and to finish the edges of the area. This means includes a blade 42, extending from a distance greater across than the width of the bucket 12 itself, for defining a finishing blade there across. Further blade 42 includes a beveled front edge 44 to form the means to finish the surface very smoothly. Blade 42 would also include an under surface 46, which would be flat, and would allow for the packing of the smooth, finished area. The blade 42 is mounted to the excavation bucket 12 through a unique mounting system 50 which allows for the secure mounting so the blade can be secure when in use, and provides for easy mounting and removal from the bucket 12. Further the manner in which the blade is mounted allows full access to the space 40 within the bucket 12 so that materials may still be moved into space 40 even with blade 42 mounted onto the bucket 12. The mounting system 50 would further comprise an upper mounting plate 52, secured to upper surface 43 of blade 42, comprising a pair of end mounting members 54, welded or the like along the blade 42, and providing that plate 52 is raised from the upper surface 43 of plate 42, for defining a receiving space 56 therein. Preferably, as seen in FIG. 9, the end of plate 52 would have a lip 5 received into an opening 53 in mounting members 54, to hold it securely in place. Receiving space 56 would receive the beveled edge 36 of a plurality of the teeth 30 from bucket 12, so that the blade, when secured as seen in the figures, is centrally positioned along the front of bucket 12. Preferably, as seen in FIG. 1, the central most teeth 30 would be secured within the space 56, with the outer most teeth set free. There would be further provided additional front support gussets 55 spaced apart along the top of plate 52, and extending forward of plate 52 welded to the upper surface 43 of plate 42, so that the materials moving over plate 52 slide along the upper surface 57 of the members 55, and do not contact plate 52. The mounting system would further comprise a pair of side walls 60 extending between the upper surface 43 of plate 42 and the front edges 17 of each side wall 14, 16 of bucket 12, so as to define a means to assure that the materials scraped by plate 42 during the operation, are channeled from the surface of the plate inwardly to the reduced opening in the space 40 of bucket 12. As illustrated in the figures, it is preferable that the position of side walls 60 be slightly tilted to the rear, so that the materials do not encounter a upright plate barrier, but are eased into the bucket space 40 by the rear-tilted side walls 60. In addition, each side wall 60 would provide a side cutter 61 mounted on the front edge of the wall, as seen in FIG. 1, which would, like the edge 44 of blade 42 act as a cutting surface. The edge 61 would be welded to the front edge of the side wall 60, and would be of hardened steel or the like material. FIGS. 2 through 6 illustrate in detail the mounting system which has been heretofore described, and the additional mounting system which is unique to the apparatus. As illustrated, for example in FIG. 5, the side walls 60, are mounted to the blade 42 via a mounting plate 67 which would in turn bolting engage to blade 42. As illustrated, this is accomplished by a first elongated mounting slot 93 which would engage a first transverse mounting slot 95 on blade 42. There would be further provided a pair of mounting slots 97, 99 on plate 67 to accommodate a pair of bolts 101 through a second transverse slot 103 of blade 42. Blade 42 may have additional transverse slots as illustrated in FIG. 10. In this manner the bolting between the mounting plate 67 and the blade 42, through the sloted openings allows the blade to be accomodated onto a variety of widths of excavating buckets. That is, once the blade is positioned via the teeth 30 of the bucket fitted into receiving space 56, the side walls would be fitted against the edge of the bucket, and once the alignment is complete, the bolts 101 are tightened, and the side walls are in place. Further, it should be noted that the side walls are further supported by a pair of gusset plates 64 and 65 mounted to plate 67, so as to help support the side walls 60. This means is clearly shown in the figures, particularly FIGS. 4 through 7. As seen in FIG. 5, there is illustrated an additional connection means which comprises a generally elongated mounting rod 70, extending from each gusset plate 64, positioned on each side of the blade 42, and each side wall 14, 16 of bucket 12. In operation, the mounting rods 70 provide stability, yet provide a means to allow the blades to be positioned upon various sizes of buckets 12, and provide for some movement between the connections. Overall, as seen in FIG. 4, the mounting rod 70 in reality comprises a series of inter-working parts. There is provided a first upper section or outer housing 72 and a second lower section 74, with the body 75 of section 74 moving into the space 77 defined by housing 72. Further there is provided a mounting means, or padeeye 80, having a ball joint 82, at each end to define the entire mounting system 70. One padeye 80 would be secured to the lower housing 74 through welding of the like and would include a ball joint 82 in padeeye 80 so that a gusset pin 84 secured to the gusset plate 64, as seen in FIG. 6A, could be inserted through the port 83 in ball joint 82 and securely mounted to padeye 80. The upper housing 72 would likewise have padeye 80 mounted on its end, housing a ball joint 82 for inserting a mounting bolt 84A through port 83 in ball joint 82 and securely mounting the upper end of the rod to the walls 14, 16 of bucket 12. As seen in FIG. 8, the walls 14, 16 of bucket 12 would be reinforced with plates 19, with the head 84B of bolt 84A recessed within plate 19 to avoid contact with material in bucket 12. However, in this case, padeye 80 would be able to rotate free of body section 72. The means for accomplishing this would be a post 85 welded or threaded onto padeye 80, and extending through the upper wall 81 of body 72. The second end of post 85 would be attached to a base member 87 would be positioned within the space 77 of housing 72, and would rotate freely within space 77, with post 85 serving as the axis of rotation. To reduce the wear between the upper wall 81 of body 72 and base member 87 there would be provided a wear bushing 89, of nylon or the like material, to provide more wear and easier rotation. Of course, the upper housing 72 must be engaged to lower housing 74. The means for accomplishing this is provided by a central bolt member 76 extending down the length of upper body 72, with the end of the bolt secured within body 72 by a mounting bushing 91 mounted onto the wall of the body 72 via welding or the like. The bolt 76 would thread into a nut 93 welded into the housing space within lower housing 74, so that rotation of housing 72 would thread bolt 76 into nut 93, to reduce or increase the length of the mounting sleeve as required, yet allow the two padeyes 80 mounted on each end to remain securely attached to the gusset plate 64 and to the wall 16 of bucket 12. Following the mounting procedure, once each end is secured in place, the free rotation of the housing 72 would impart rotation to bolt 76 within threaded port 78, and depending on the rotation of housing 72, would provide for the extension of the retraction of the overall length of rod 70. This is necessary, since the blade 42 may be mounted to various size buckets, and would require that the rod 70 have the capability to retract and extend as required. It should be noted, also, that the configuration of the housing 72 around the threaded bolt 76 provides for protection of the bolt from outside knocks of the like. Further, since each padeye 80 includes a ball joint 82, this allows for some swiveling movement of the mounting rod 70 of the between the blade 42 and the bucket 12, as seen in phantom view in FIG. 8, rather than having a rigid attachment, which allows for accomodating varied bucket widths. As seen further in the figures, once the rod 70 has been properly adjusted, there is provided a set screw 90 in the wall of housing 72, so that when secured, prevents further rotation of housing 72, until desired. Further is provided a grease fitting 92 on the wall of housing 42 so that grease may be injected in to the housing to prevent rusting or corrosion of the internal connections between the body portions of rod 70. In most cases, when the blade 42 is secured to the bucket 12, the walls 14, 16 of bucket 12 will be accommodated with holes so that the rod 70 may be secured therethrough. However, in certain instances, a hole may have to be drilled into a bucket wall to accommodate the mounting bolt, and when this is done, the hole is prepared to accommodate the mounting bolt for proper installation. Glossary of terms apparatus 10 bucket 12 sidewalls 14, 16 front edges 17 reinforcing plates 19 base portion is upright portion 20 floor 22 upper portion 24 arms 26 teeth members 30 front edge 32 body portion 34 beveled edge 36 point 38 space 40 blade 42 upper surface 43 front edge 44 under surface 46 mounting system 50 lip 51 upper mounting plate 52 opening 53 mounting members 54 support gussets 55 receiving space 56 side walls 60 side cutter 6 gusset plates 64, 65 mounting plate 67 mounting rod 70 outer housing 72 lower section 74 body 75 space 77 threaded bolt 76 threaded port 78 padeye 80 ball joint 82 retaining piston 82A port 83 gusset pin 84 bolt 84A head 84B nut 84C post 85 base member 87 wear bushing 89 set screw 90 mounting bushing 91 grease fitting 92 nut 93 first transverse mounting slot 95 mounting slots 97, 99 bolts 101 second transverse mounting slot 103 Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.	An improved excavating bucket, having a pair of sidewalls, a rear wall, a floor portion and an open front portion for receiving material thereinto; a plurality of teeth members secured to the floor portion for digging into the material to be excavated; a finishing blade mounted to the bucket, the blade extending across a width greater than the width of the bucket opening, and having a forward edge for scraping; a raised channel formed on the upper face of the blade for engaging a plurality of the teeth members; sidewall members extending from the outer edges of the blade for engaging the wall of the bucket, for defining an uninterrupted travelling space for material into the bucket; and adjustable support rods able to be swivelly positioned between the blade and the bucket sidewalls to stabilize the blade mounted on the bucket.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATIONS [0001] This patent application relates and claims priority to provisional patent application 61/077,007, filed Jun. 30, 2008, which is herein incorporated by references for all purposes. TECHNICAL FIELD [0002] This disclosure relates generally to roofing products, and more particularly to the use of a fastening system and method for a thermoplastic olefin (TPO) roofing membrane. BACKGROUND [0003] A single ply building membrane is a membrane typically applied in the field using a one layer membrane material (either homogeneous or composite), rather than multiple layers built-up. These membranes have been widely used on low slope roofing and other applications. The membrane can comprise one or more layers, have a top and bottom surface, and may include a reinforcing scrim or stabilizing material. The scrim is typically of a woven, nonwoven, or knitted fabric composed of continuous strands of material used for reinforcing or strengthening membranes. Such single ply membranes typically comprise base (bottom) and cap (top) polyolefin-based sheets (layers) with a fiber reinforcement scrim (middle) sandwiched between the other two layers. The scrim is generally the strongest layer in the composite. Other materials from which the membranes may be formed include, but are not limited to, polyvinyl chloride (PVC), chlorosulfonated polyethylene (CSPE or CSM), chlorinated polyethylene (CPE), and ethylene propylene diene terpolymer (EPDM). [0004] A typical method of preparing membranes having scrims comprises unwinding a support sheet, scrim, or stabilizing material, and coating the support material by extrusion of a molten compounded polymers, including one or more fillers, UV and thermal stabilizers, and various pigments and fire retardant agents. Then the process provides for cooling and solidifying the membrane, and winding the membrane into a roll. A novel scrim for use with such single-ply roofing membranes is disclosed in co-pending patent application U.S. 2006/0292945, which is commonly assigned with the present disclosure and incorporated herein by reference in its entirety. [0005] Single ply heat welded membranes are the fastest growing segment of the low slope roofing materials market. The two main membranes are produced from either thermoplastic olefin (TPO) or polyvinyl chloride (PVC) polymer. In both cases, the membranes consist of two layers of the polymer with a reinforcement scrim laminated in-between, as mentioned above. Such membranes are supplied as wide sheets, typically about 4 to 10 feet wide, in rolls up to 200 feet length. A particular advantage of these membranes is that they can be overlapped and then heat welded together. This results in a monolithic membrane with significantly reduced risk of leakage. [0006] Roofing systems get tested in a wide variety of ways. In one particular test, the intent is to measure how well a system would stay intact when exposed to high wind loads. Typically, high wind loads result in upward forces that can result in part or all of the roofing system lifting off. To test for this so called “wind uplift” resistance, a deck is built to replicate a roof construction. Typically, these are 10 ft×20 ft or larger assemblies that include a welded seam where the end of one piece of the roofing membrane is connected to the beginning of another membrane sheet. The decks are sealed underneath in such a way that the underside of the roofing system can be pressurized. The pressure is then raised in increments until failure of the roofing system, namely, when the roofing system begins to lift off of the structure. The pressure prior to failure is then the rating of that particular roofing system. [0007] Single ply membranes in low slope applications are typically installed above a layer of insulation such as polyisocyanurate (polyiso) slab stock foam. Polyiso foam is produced with a facer on either side, typically a cellulosic felt or paper. [0008] Closely spaced mechanical fasteners used for mechanical attachment of the overlap section of the two membranes to the underlying roofing structure in the conventional method of installation. Such mechanical fasteners typically consist of metal plates and screws that penetrate down through the insulation (polyiso boards) and into the supporting steel or other type of deck material. [0009] However, such conventional roofing assemblies provide for fastening only along the weld seam via fasteners driven down into the steel deck for the mechanical attachment of just the overlap portion of the membranes. Unfortunately, this means that for wide sheets there can be up to a 10 feet span between attachment points in one direction. System designs attempt to compensate for such a large span between attachment points by increasing the density of fasteners in the other direction, sometimes by moving them as close as 6 inch on center. However, this has a cost impact and has limited benefit. [0010] An alternative method of securing single ply roofs has been commercialized by O.M.G. Inc located in Massachusetts. O.M.G. sells round metal plates that have been coated with a thermoplastic polymer (or PVC) that acts as a hot melt adhesive. These are currently being sold under the name RhinoBond®. Such plates are distributed evenly using around 6 per 4×8 foot polyiso foam board, and are attached to the roof structure using conventional roofing screws. Such screws hold the plates in place and penetrate through the insulation boards and down into the steel deck, thereby better anchoring the roofing system. Once the membrane is in place over the foam boards having the coated round plates, an induction heater is used to heat each plate in turn, melting the adhesive coating and gluing the plates to the membrane along the locations where the plates have been located. However, even with this approach, installation time is even longer since each coated plate must first be mechanically attached through the insulation board and into the underlying roof structure. [0011] Accordingly, there is a need for an improved technique for securing single ply roofing membranes to the roofs of structures that does not suffer from the deficiencies found in conventional approaches. For example, simpler installation steps resulting in faster installation times would be especially desirable. The principles disclosed herein provide such a technique. SUMMARY [0012] This invention relates to an improved fastening technique for heat-weldable single ply roofing membranes comprised of thermoplastic polymer material. In one embodiment, the technique involves strips of rigid material such as metal coated on exterior surfaces with thermoplastic polymer material, incorporated into the upper surface of polyisocyanurate insulating foam boards. In an alternative embodiment, such rigid strips are simply laid out across the entire roof surface. In either approach, once the membrane is laid out over the coated strips, which are laid out over the insulation boards or directly on the roofing deck if boards are not used, the coated strips are heated, for example, with an induction heater, such that the thermoplastic polymer coating on the strips becomes fused on the exterior side to either the insulation boards or the roofing deck and on the interior surface to the thermoplastic polymer-based membrane. In yet another embodiment of the disclosed technique, the coated strips may be incorporated into the surface of an underlayment, such as GAF-Elk's Versashield®, which functions as an underlying layer for the single ply membrane. In this embodiment, the underlayment having the incorporated coated strips is installed over the roofing deck using mechanical attachments, and then a heating device is used after the membrane is laid over the underlayment to fuse the thermoplastic polymer material on the interior surface of the rigid strips to the membrane. In all embodiments, the overlap portion between adjoining membrane sheets may also be heat welded and/or secured with a mechanical fastener, as found in conventional approaches. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 illustrates a top down view of the installation of a conventional polyiso single ply system; [0014] FIG. 2 illustrates a partial side cross-sectional view of the installation of a conventional polyiso single ply system; [0015] FIG. 3 illustrates a top down view of the installation of a polyiso single ply system in accordance with the present disclosure; and [0016] FIG. 4 illustrates a partial side cross-sectional view of the installation of a polyiso single ply system in accordance with the present disclosure. [0017] FIG. 5 illustrates a partial side cross-sectional view of the installation of a polyiso single ply system in accordance with the present disclosure. [0018] FIG. 6 illustrates a partial side cross-sectional view of the installation of a polyiso single ply system in accordance with the present disclosure. [0019] FIG. 7 illustrates a partial side cross-sectional view of the installation of a polyiso single ply system in accordance with the present disclosure. DETAILED DESCRIPTION [0020] FIG. 1 illustrates a top down view of the conventional installation of a single ply membrane. The membrane sheets are laid down with a section of overlap 103 . Closely spaced mechanical fasteners 105 are used for mechanical attachment of the bottom layer at the overlap section 103 of the two single ply membranes 102 to the roof structure. Such mechanical fasteners 105 typically consist of metal plates and screws that penetrate down through the insulating boards 101 . The overlapping section 103 is then heated creating a heat weld 104 . [0021] FIG. 2 illustrates the partial cross-sectional view of the installation of a single ply membrane 102 shown in FIG. 1 . The insulating board 101 is shown layered on top of the steel or other type of deck material 201 . Two sheets of single ply membrane 102 are shown on top of the insulating board 101 aligned so that there is a section of overlap 103 between them. The mechanical fastener 105 is shown penetrating through the bottom one of the single ply membranes 102 and through the insulating board 101 into the decking material 201 . The overlapping section 103 is then heat welded as mentioned above. The mechanical fastener 105 and the heat weld 104 are located within the overlap region 103 of the two single ply membranes 102 . [0022] FIG. 3 illustrates a plan view of one embodiment of a roof installation technique in accordance with the disclosed principles. This figure also shows the single ply membrane 102 with a section of overlap 103 layered on top of the insulating board 101 . The overlap 103 is heated to form a heat weld 104 that holds the two sheets of single ply membrane 102 together. [0023] The technique in accordance with the present disclosure avoids the use of individual plate fasteners 105 used in the conventional process described above. Instead, in one embodiment, rigid strips 301 having heat-weldable thermoplastic polymer material on exterior and interior surfaces are used to provide for a more continuous adhesion of the membrane 102 down onto the insulating boards 101 . As used herein, the term “rigid” when referencing the strips 301 means that the strips are resistant to bending or flexing and are sufficiently stiff to maintain their linear shape. However, it does not mean that the strips are not flexible at all, such as with a metal tape measure that is extremely rigid from side-to-side, but somewhat flexible up and down. Moreover, the rigid strips 301 may be formed in lengths from about 3 ft to about 10 ft, and may be about one-half inch to several inches wide and from 1/16 inch to ¼ inch thick. Of course, other sizes may also be employed for the rigid strips 301 . [0024] The insulating boards 101 are first laid across the roofing deck and secured to the roofing deck. Securing of the insulating boards 101 may be done using mechanical fasteners driven through the boards 101 and down into the roofing deck. Alternatively, an adhesive, such as a urethane adhesive, may be used to adhere the insulating boards 101 onto the roofing deck. Once the insulating boards 101 are secured to the roofing deck, the rigid strips 301 are periodically dispersed on the exterior surface of the insulating boards 101 . Exemplary spacing between each rigid strip 301 may be 36 inches, however, other amounts of spacing may also be selected. The single ply membrane 102 is then laid on top of the rigid strips 301 , and the overlap sections 103 between separate membrane sheets 102 may be heat-welded together. For example, a heated mandrel may be moved along the overlap section 103 between the overlapping membranes pieces 102 . As the mandrel moves along the overlap section 103 , the mating surfaces of the overlapping membrane pieces 102 are heated and then pressed together to complete the heat weld seal between the two. Of course, other techniques for heat-welding or otherwise bonding the overlap section 103 may also be employed. [0025] After the membrane has been laid out across the roofing deck, the membrane 102 is heated directly above the locations of the strips 301 . Once heated, the thermoplastic material on the exterior or upper surface of the rigid strips 301 fuses directly with the single ply membrane 102 . In this embodiment, the heating also causes the thermoplastic polymer material on the interior or lower surface of the rigid strips 301 to adhere the strips 301 to the polyiso insulating boards 101 , or directly to the roofing deck 201 if no insulating boards 101 are employed. One advantageous technique that may be employed to perform the heating of the thermoplastic material on the rigid strips 301 in the above-described manner is via induction heating. For example, a heated roller may be rolled across the membrane 102 directly over the rigid strips 301 , where the heat from this roller device is transferred through the membrane 102 to the thermoplastic polymer on the rigid strips 301 sufficient to melt the thermoplastic material and adhere the components together as described above. Other techniques to heat the thermoplastic polymer material on the rigid strips 301 sufficiently to adhere to the membrane 102 and to the insulating boards 101 (if employed) may also be employed. For example, hot air may be directed at the areas of the membrane 102 where the rigid strips 301 are located to cause the desired adhesion. Also, a heated iron or similar flat device may be slid across the membrane 102 in the appropriate locations to cause the desired melting and adhering of the components. Of course, other heating techniques may also be employed, however, some heating techniques may not be sufficient as they may melt the membrane 102 before transferring enough heat down to the rigid strips 301 to melt their coating. Accordingly, heating by heat induction is the preferred embodiment. [0026] An advantage of this novel technique is that adhesion of the membrane 102 to the insulating board 101 or other surface can be improved since any number of rigid strips 301 may be employed at any location across the membrane 102 . As a result, wind uplift performance (related to the system's ability to withstand severe weather conditions) is improved. In addition, wider sheets of single ply membrane 102 can be installed without compromising roofing performance since the mechanical attachment of the membrane sheets 102 is not only at the overlap between adjoining sheets 102 , as is the case in the conventional installation method described in FIGS. 1 and 2 , but also along the length of each rigid strip 301 . An additional advantage is that installation of the roofing system would be easier than conventional approaches where the insulating boards 101 are adhered to the roofing deck since the installer does not need to handle washers or mechanically fasten coated plates down to the roofing structure. Accordingly, faster installation times and less installation materials results in overall costs being lowered. [0027] FIG. 4 illustrates a partial side cross-sectional view of the installation technique described in this disclosure. Again, the figure illustrates the use of the insulating boards 101 layered on top of the roof decking 201 . As discussed above, the insulating boards 101 may be mechanically fastened to the roofing deck 201 or they may be adhered. Rigid strips 301 with thermoplastic polymer material on both exterior and interior (i.e., upper and lower, when mounted) surfaces are located between the polyiso foam insulation board 101 or roofing deck 201 and the single ply membrane sheets 102 . The membrane sheets 102 can be heated to form a heat weld 104 at the location of their overlap 103 , as described above. Also as described above, the thermoplastic material on the exterior and interior surfaces of the rigid strip 301 can also be heated using induction heating, or other appropriate heating technique, to fuse the rigid strip 301 directly to the single ply membrane 102 and either the roofing deck 201 or the polyiso foam boards 101 , depending on what the strips 301 are directly contacting in each particular installation. [0028] FIG. 5 illustrates an embodiment of the disclosed principles in which insulation foam boards 101 are manufactured with rigid strips 301 , for example, made of metal or other rigid material, incorporated into the exterior surface of the insulating boards 102 . These rigid strips 301 are coated on their exterior surface with a thermoplastic polymer material, such as TPO, and are built into the facer on the top/exterior surface of the foam boards 101 . Once the insulation boards 102 having these strips 301 are installed on the roof structure, the membrane 102 is laid over the boards 101 . A heating device is then used to fuse the coating of thermoplastic polymer material 501 on the strips 301 to the membrane 102 as described above. Since the strips 301 are built into the boards 101 , and the boards 101 have been secured to the roof structure 201 (e.g., mechanically or adhesively), the membrane 102 is secured to the roof structure 201 where the strips 301 have been laid out. In addition, the strips 301 may have holes at periodic positions along their lengths to provide for mechanical attachments that penetrate down to the roofing deck 201 . Moreover, mechanical fasteners used to secure the rigid strips 301 may simultaneously be the means by which the insulating boards 101 are secured to the roofing deck 201 . [0029] FIG. 6 illustrates another embodiment of the disclosed principles in which the rigid strips 301 may be incorporated into the surface of an underlayment 601 , such as GAF-Elk's Versashield®. Such an underlayment 601 functions as an underlying sealing layer for single ply membranes. In this embodiment, the underlayment 601 having the incorporated rigid strips 301 is installed on the insulation boards 101 using conventional techniques. The membrane 102 is then laid over the underlayment 601 , and a heating device is used to fuse the coating 501 on the strips 501 to both the membrane 102 and the underlayment 601 . Again, such strips 301 could have holes arranged longitudinally for mechanical attachment down into the roofing deck 201 . Also, insulation boards 101 may or may not be used with this approach. Since the strips 301 are integrated into the underlayment 601 , and the underlayment 601 has been secured to the roof structure 201 or to insulation boards 101 secured to the roof structure 201 , the membrane 102 is now secured to the roof structure 201 where the strips 301 have been laid out by the selected heating and fusing process. [0030] FIG. 7 illustrates another embodiment in which polyiso foam insulation boards 101 are manufactured with a foil facer 702 . The foil facer 702 would be coated with lines of hot melt adhesive 701 . Again the insulation boards 101 are installed on the roof structure 201 , and the membrane sheets 102 laid over them. A heat device is then used to melt and adhere the adhesive strips 701 to the foil 702 (or other sturdy material) of the insulation boards 101 . Also, the heating of the thermoplastic material 501 on the exterior surface of the rigid strips 301 bonds the strips 301 to the membrane 102 , as in previous embodiments. Since the insulating boards 101 have been secured to the roof structure 201 , and the rigid strips 301 adhered to the boards 101 with the hot-melt adhesive 701 and bonded to the membrane 102 , the membrane 102 is now secured to the roof structure 201 where the rigid strips 301 have been located. [0031] Yet another approach is the laying out of continuous strips of precoated metal 301 across the entire roof surface. These coated strips 301 would be laid over the insulation boards 101 that have been secured to the roof structure 201 . The coated strips 301 may have holes at periodic positions along their length to provide for standard mechanical attachments that would simply hold the rigid strips 301 from moving around while the membrane 102 is laid on top of the strips 301 . The membrane 102 is then laid over the rigid strips 301 , and a heating device is used to fuse the thermoplastic polymer material on the strips 301 to both the membrane 102 and the underlying roof structure 201 or insulation boards 101 . Thus, the coating is what structurally bonds the strip 301 to the roofing deck 201 , and the strip 301 to the membrane 102 , rather that a large number of roofing screws used to structurally secure the strips to the deck. Not only does this cut the installation time significantly, but it also allows securing the membrane 102 to the roofing deck 201 without making a large number of holes through the deck. [0032] While various embodiments in accordance with the disclosed principles have been described above, it should be understood that they have been presented by way of example only, and are not limiting. Thus, the breadth and scope of the invention(s) should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the claims and their equivalents issuing from this disclosure. Furthermore, the above advantages and features are provided in described embodiments, but shall not limit the application of such issued claims to processes and structures accomplishing any or all of the above advantages. [0033] Additionally, the section headings herein are provided for consistency with the suggestions under 37 C.F.R. 1.77 or otherwise to provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Specifically and by way of example, although the headings refer to a “Technical Field,” such claims should not be limited by the language chosen under this heading to describe the so-called technical field. Further, a description of a technology in the “Background” is not to be construed as an admission that technology is prior art to any invention(s) in this disclosure. Neither is the “Summary” to be considered as a characterization of the invention(s) set forth in issued claims. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims issuing from this disclosure, and such claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of such claims shall be considered on their own merits in light of this disclosure, but should not be constrained by the headings herein.	This invention relates to an improved fastening technique for single ply roofing membranes comprised of thermoplastic polymer material. In one embodiment, a method of installing a roof on a structure may comprise providing a single-ply roofing membrane comprising thermoplastic polymer material, and periodically securing rigid strips over a roofing deck. In such embodiment, the rigid strips have thermoplastic polymer material on corresponding exterior surfaces thereof. The method may further include laying the roofing membrane over the roofing deck, where the rigid strips are located between the roofing deck and the roofing membrane. Then the method may include heating the roofing membrane and the rigid strips simultaneously, perhaps using a heat induction technique, such that thermoplastic polymer material on the exterior surfaces of the rigid strips fuses directly with the thermoplastic polymer material of the roofing membrane.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION Oil shale represents a vast untapped resource of liquid hydrocarbon fuel; potentially, it could be a source for a synthetic fuel substitute to replace the ever-diminishing supply of domestic petroleum. There are over 2 trillion barrels of synthetic fuels locked up in oil shale deposits in the United States. Oil shale occurs in zones up to several hundred feet thick but typically the richest zone is from 50-100 feet thick. The oil shale is found in the rock in the form of kerogen, a high molecular weight hydrocarbonaceaous material. Heating oil shale in a device termed a reort results in the decomposition of the kerogen and formation of the liquid known as shale oil. Oil shale retorting can be carried out in situ, that is in place in the ground, or it can be carried out in a process facility on the surface. In order to carry out retorting on the surface, it is necessary to mine the ore. The most commonly proposed technique to carry out the mining of oil shale has been the room and pillar method as illustrated in FIG. 1. The room and pillar method is discussed in Chapter 5 of "An Assessment of Oil Shale Technologies", by the Office of Technology Assessment (June 1980) and in "Oil Shale Mining--Present and Future" by R. B. Crookston and D. A. Weiss taken from "Symposium Papers, Synthetic Fuels from Oil Shale II", Nashville Tenn. Oct. 26-29, 1981, Institute of Gas Technology, p. 417. In the room and pillar design, the deposit is blocked into mining panels having a panel entry area 10 which may range from 900 to 1500 feet wide. Rooms 14 which are approximately 60 feet wide, the depth of a panel and the height of the mining zone are mined between the rooms leaving a pattern of square pillars 18 from 65 feet to 90 feet on a side to support the roof. Barrier pillars 19 are 65 feet in width but 400 feet in length to separate the panels to assure any pillar failure within a panel will not progress beyond the limits of the panel. Given dimensions vary with the quality of the rock and the depth of the overburden. The panels are mined in three separate and distinct operations: heading extraction, bench extraction and crosscut extraction. Within the panel the upper extraction, termed the heading, about one-third to one-half of the height of the mining zone is driven within the boundaries of rooms and just below the roof (the top of the mining zone). When the headings are sufficiently advanced, the floor of the heading, i.e., the lower portion of the mining zone is mined. This operations called benching, ranges in depth but averages from one-half to two-thirds of the mining horizon. Benching is advanced in the same direction as the heading. While some crosscuts are taken during the heading advance, most are executed after the benching operation is completed. The mining consists of several tasks; namely, drilling the blastholes, charging blastholes with explosives, blasting, water application to suppress dust, scaling down the loose rock, loading out the broken rock into trucks and hauling it to the crusher, and supporting the roof with steel rock bolts. The broken rock in the dump trucks is hauled to a stationary crusher (not shown) located near a slope conveyor in panel entry 10. The shale is crushed and conveyed to the surface via the slope conveyor. Haulage by means of trucks presents a number of safety and logistical problems. The trucks exiting from the panel must traverse a ramp 12 from the heading or bench entries to panel entry 10. Because of the steep grade on ramp 12, the trucks will be subjected to substantial wear. In addition, the steep and narrow ramps 12 will tend to cause frequent accidents. Further, a significant logistical problem can occur at the crusher if the trucks do not arrive on schedule. Trucks off schedule could cause queuing of the rocks at the crushers, resulting in loss of efficiency and productivity. The heading and benching operations produce oil shale of substantially different grade. In order to maintain constant grade of ore to the retort, the ore must be delivered to the crusher on a preset schedule. For example, in the case of the room and pillar mine discussed above, for every truck from the heading area one or two trucks should come from the bench mining area. In view of the numerous possibilities for delay in arrival of the truck e.g., mechanical breakdown, accidents, unavailability of ore, etc., the use of trucks for haulage of oil can result in frequent failure to maintain a constant grade of oil shale to the retorts. In addition, if the mine is deemed gassy, special requirements relating to mining equipment apply. At present, the large scale trucks required for oil shale haulage are not commercially available for use in gassy mines and would have to be specially fabricated to operate in a gassy mine. An additional difficulty with a room and pillar mine layout is in the ventilatio requirements. Ventilation may be accomplished by drawing air in one side of the room and pillar design and exhausting out the other. Because of the numerous crosscuts present, proper ventilation becomes virtually impossible. As a result, it is necessary to use numerous curtains or brattices (not shown) to direct the air into rooms where the mining is taking place and close off those areas not undergoing mining. Because the proper seal of the opening is difficult to achieve, these brattices have a tendency to leak. Therefore, while proper ventiltion can thereby be achieved, a substantial amount of power still must be used. The presence of numerous crosscuts results in the need to utilize substantial quantities of power to maintain proper airflow. Support of the roof of underground mines is an important and expensive procedure. To prevent collapse of portions of the roof, the room and pillar must be designed to withstand the pressure of the rock above and the suspended weight of the roof over the room opening. At an intersection 20 of a room 14 and a crosscut 16, this problem becomes more substantial due to the locally large spans produced by the intersections of crosscut and room tends to be weaker and requires additional maintenance. Minimizing crosscuts would reduce these maintenance costs and decrease the safety risks. SUMMARY OF THE INVENTION The present invention solves the foregoing problems of mining such as ventilation requirements, ramp access, extensive overhead support restrictions and safety hazards by providing a multilayered mining system and a modified layout of pillars and rooms. Parallel entries, and bench or lower entry and heading or upper entry, are mined perpendicularly to a main entry. Lanes, or rooms, driven perpendicularly to the heading entry are completed to a predetermined distance from the bench entry. A stub is driven from the bench entry toward the heading entries. The two levels are connected by driving a vertical slot raise to create a bench face. Oil shale is mined from the bench face and from the heading level. Portable crushers are located in an adjacent entry to receive oil shale from load-haul-dumps for placement on entry conveyors. The entry conveyors transport crushed oil shale to a primary conveyor in the main entry for transportation to the surface for further processing. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a room and pillar mining operation. FIG. 2 is a plan view of a lane and pillar mining operation. FIGS. 3A and 3D are side view of FIG. 2. FIG. 4 is a partially cutaway isometric view of the operation of FIG. 2. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 2, a land and pillar design 30 of the present invention is illustrated as having lane 32 and crosscuts 34 defining pillars 36. One end of lane 32 is terminated by bench entry 38 and the other end is terminated by heading entry 40. Bench entry area 38 and heading entry area 40 are formed perpendicular to main entry area 42 with wide support pillars 44, a barrier pillar 46 isolates main entry area 42 from the mining area defined by lanes 32 and crosscuts 34 supported by pillars 36. Main entry area 42 is mined or excavated followed by mining heading entry 40 and bench entry 38. A lane 32 is mined from heading entry 40 to a location prior to bench entry 38 at a level equal to that of heading entry 40. Lane 32 is completed from bench entry 38. FIG. 3A illustrates a completion of heading entry 40 and the commencement of mining a lane. A conveyor belt 48 is located in one of heading entry 40 tunnels. In the preferred embodiment heading entry 40 comprises three tunnels with conveyor 48 located in the center tunnel to provide access from either side. However, any number of tunnels may be used and conveyor 48 has access to a conveyor belt 50 (See FIG. 4) in main entry area 42. As lane 32 is mined, a load-haul-dump vehicle 51 transports mined material to portable crusher then to conveyor 48 for transportation to conveyor belt 50 in main entry area 42. FIG. 3B illustrates the completion of lane 32 along with the start of bench entry 38. Heading entry 40 and bench entry 38 are each approximately twenty-five feet high with a vertical separation approximately twenty-five feet between the roof 52 of bench entry 38 and the floor 54 of heading entry 40. Bench entry 38 comprises three tunnels having a conveyor 56 located in the center tunnel in the preferred embodiment. However, as stated in conjunction with heading entry 40, bench entry may be of any number of tunnels and conveyor 56 may be located in any tunnel as long as one end of conveyor has provision to load mined materials on conveyor belt 50 in main entry 42. A drilling vehicle 58 is illustrated as drilling through the floor of lane 32 to the ceiling level of bench stub 70 off bench entry 38. A ledge extends out from the end of surface of lane 32 nearest bench entry 38. The holes between bench stub 70 and the upper portion of lane 32 are blasted to provide a slot raise 74 as illustrated in FIG. 3C. Similar to removal of mined material from the upper portion of lane 32, load-haul-dump vehicle 76 transports mined material from a bench face 78 to a portable crusher which loads onto conveyor 56. Referring now to FIG. 3D, advancement of bench mining operations is illustrated. Bench face 78 is continually moved from bench entry 38 toward heading entry 40, removing mined material by vehicle 76 to portable crusher (not shown) to conveyor 56. In an alternate embodiment, conveyor belts (not shown) may be located in adjacent lanes 32 and may be used in conjunction with a portable crusher (not shown). Vehicle 76 may load mined material in one lane 32, haul it through crosscut 34 and dump it into a portable crusher located in an adjacent lane 32 or several lanes away. In operating in this manner, productivity of vehicles 58 and 76 is increased. In FIG. 4 a perspective view of the mining operation of the present invention is illustrated. In lane 32A, the heading level is illustrated as having progressed past crosscut 34A and roof bolting is occuring at 80. Mining of lanes 32 may be done by any mining practice in use in the art. However, the preferring embodiment uses a method wherein the mine face is drilled, blasted and the mined material removed. The walls and roof of lanes 32 are scaled to provide a generally even surface with a minimum of loose rocks. In lane 32B, mining has progressed past crosscuts 34A, 34B and 34C nad mucking or material removal is illustrated at 82. In lane 32C, scaling of the lane walls before and during mucking is illustrated at 84. In lane 32D, powdering is ilustrated at 86 in preparation for blasting the lengthen lane 32D towards bench entry area 38. Lane 32E is illustrated as having slot raise 78 completed (see FIG. 3C) and mining from bench entry 38 level may commence. In lanes 32E, 32F and 32G, ledge 72 is illustrated as extending out from the bench level 38 to end below their respective heading entry area 32 levels. The mining process begins with providing main entry area 42. A main conveyor belt 90 is placed in main entry area 42 when a transfer raise 92 for rock has been provided to connect main entry area 42 with heading entry area 40. The unloading from bench belt 93 and headings belt 94 includes cascading material through transfer raise 92 onto main entry conveyor belt 90 in the case of headings belt 94 and unloading bench belt 90 in the case of headings belt 94 and unloading belt 93 directly onto main entry conveyor belt 90 in the case of bench belt 93. The flow of the material is directed and controlled onto main entry conveyor belt 90 by means of chutes or regulated feeders (not shown) in both instances. Bench area 38 and heading entry area 40 are provided simultaneously in the preferred embodiment, although their exact sequence may be as desired. Lanes 32 are mined at the heading entry area 40 level. Access ramp 102 is driven from mains area 42 to facilitate initial development of heading entry area 40. Mined material is loaded on vehicle 76 and transported to transfer raise 92. The crushed material is dumped through transfer raise 92. The crushed material is dumped through transfer raise 92 and loaded onto main entry conveyor belt 90, where it is transported to the surface for further processing. Lanes 32 are generally perpendicular to heading entry 40 and extend toward bench entry 38. Lanes 32 are mined at a level equal to the level of heading entry 40. Prior to extending bench entry area 38, the heading entry 40 level of lane 32 is connected to the start of a bench entry 38 level of lane 32 by drilling from heading entry 40 level to bench entry 38 level. The drilled holes are blasted (see FIGS. 3B and 3C) to provide a slot raise. In the preferred embodiment, the distance from the top of lane 32 to floor 54 of heading entry 40 level is approximately one third of the distance from the top of lane 32 to the bottom or floor level of bench entry 38. However, any ratio of bench entry 38 mined area to heading entry 40 mined area may be used, the basic principle being a mining system, with mining being done from both bench entry 38 and heading entry 40. This alleviates logistical problems associated with a single access to a multiple operation area by providing separate access to both portions of the mining extraction process. Heading entry 40 and heading level lanes 32 are done first to permit mining to connect to bench entry 38. Furthermore, the connection through the slot raise 78 allows fresh or intake air to be easily circulated to the area surrounding mining face 78 without the requirement of large air blowers or circulating pumps. Referring to FIG. 4, the air ventilation system is illustrated as having solid lines with arrows indicating intake air and broken lines with arrows indicating exhaust air. Intake air enters through bench entry area 38 and enters the mining area through lanes 32E, 32F and 32G. Air entering in lane 32G is permitted to travel towards heading entry 40 across bench face 78G and out through exhaust area 100. Similarly, air entering lane 32F is permitted to travel across face 78F through heading entry area 40 and out through exhaust area 100. Air entering slot raise 72 into lane 32E by brattices 104A, 104B and 104C blocking crosscuts 34D and 34E and lane entry area 106E respectively. Since no mining is being done in lane 32E, no air flow is required to remove mining dust, gases or diesel fumes from vehicles 76. At bench entry 38 end of lane 32D powdering is being conducted and air flow is necessary for the work area at 86. Blower 108 is used to force intake air towards powdering work area at 86. The exhaust air then travels down lane 32D toward heading entry area 40 and out through exhaust area 150. Intake air also travels through crosscut 34F to scaling area at 84. The exhaust air travels partially down lane 32C to crosscut 34B since brattice 104D prevents air flow through entry area 106C to heading entry area 40 through lane 32C. A portion of the intake air flows to mucking area at 82 through crosscut 34C and is exhausted down lane 32B. A final portion of the intake air travels through crosscut 34A to roof bolting area at 80 by blower 110 and is exhausted down lane 32A. Blowers 108 and 110 are used since their respective work areas are a significant distance from the source of intake air at the crosscuts. Blowers are not used in lanes 32B and 32C since their respective work areas are relatively close to intake air at crosscuts 34C and 34F respectively. However, on occasions blowers may be required. Blowers are also used in lanes with a large cross section to prevent stratification of gases in the mine atmosphere. The mining method of the present invention is performed by excavating main entry area 42 and providing it with a main conveyor belt 90. Heading entry 40 is mined, the material being removed on conveyor 48 and loaded on conveyor 90 through transfer raise 92. Bench entry areas 38 is completed, the material mined being removed on conveyor 56 and loaded on conveyor belt 90. Before removal by either conveyor, mined material goes through portable crushers for reduction to a size that can be easily handled by the conveyors. The upper level of lanes 32A through 32C are mined from heading entry 40 towards bench entry 38. Slot raise 74 is driven to connect the bench entry 38 level of the mine to the completed upper level of lanes 32A through 32G to create mining face 78. Mined material from face 78 is transported by load-haul-dump (LHD) vehicles 76 to conveyor belt 56, which in turn loads onto conveyor belt 90 for further processing. Conveyor belts may be placed in lanes adjacent to the one being mined to reduce the transporting distance required by vehicles 76. Brattices, such as brattices 104A through 104D, may be put in position to direct the flow of intake air flowing from bench entry 38 to heading entry 40. Additional blowers 108 and 110 may be used to direct intake air where necessary. While the present invention has been described by way of a preferred embodiment illustrating a small mining system, it is to be understood that it should not be limited thereto but only by the scope of the following claims:	This system develops an ore body in two lifts, driven from opposite ends (at different times) and utilizes the concept of lane pillars rather than square block pillars. These conditions generate a new ventilation system that is flexible and well suited for the varying air requirements in oil shale mining. The ore handling system is load-haul-dump (LHD) to portable crushers to belts to surface. The layout of this method introduces unique functions for this system by creating two directional ore flow from the workings, which optimize logistics and material handling methods.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND 1. Field of the Invention Gutter covering systems are known to prevent debris from entering into the open top end of a rain gutter. When debris accumulates within the body of a rain gutter in an amount great enough to cover the opening of a downspout-draining hole the draining of water from the rain gutter is impeded or completely stopped. This occurrence will cause the water to rise within the rain gutter and spill over it's uppermost front and rear portions. The purpose of a rain gutter: to divert water away from the structure and foundation of a home is thereby circumvented. 2. Prior Art The invention relates to the field of Gutter Anti-clogging Devices and particularly relates to screens with affixed fine filter membranes, and to devices that employ recessed wells or channels in which filter material may be inserted, affixed to gutters to prevent debris from impeding the desired drainage of water. Various gutter anti-clogging devices are known in the art and some are described in issued patents. U.S. Pat. No. 5,557,891 to Albracht teaches a gutter protection system for preventing entrance of debris into a rain gutter. Albracht teaches a gutter protection system to include a single continuous two sided well with angled sides and perforated bottom shelf 9 into which rainwater will flow and empty into the rain gutter below. The well is of a depth, which is capable of receiving a filter mesh material. However, attempts to insert or cover such open channels of “reverse-curve” devices with filter meshes or cloths is known to prevent rainwater from entering the water receiving channels. This occurrence exists because of the tendency of such membranes, (unsupported by a proper skeletal structure), to channel water, by means of water adhesion along the interconnected paths existing in the filter membranes (and in the enclosures they may be contained by or in), past the intended water-receiving channel and to the ground. This occurrence also exists because of the tendency of filter mediums of any present known design or structure to quickly waterproof or clog when inserted into such channels creating even greater channeling of rainwater forward into a spill past an underlying rain gutter. Filtering of such open, recessed, channels existing in Albracht's invention as well as in U.S. Pat. No. 5,010,696, to Knittel, U.S. Pat. No. 2,672,832 to Goetz, U.S. Pat. Nos. 5,459,350, & 5,181,350 to Meckstroth, U.S. Pat. No. 5,491,998 to Hansen, U.S. Pat. No. 4,757,649 to Vahldieck and in similar “reverse-curved” inventions that rely on “reverse-curved” surfaces channeling water into an open channel have been known to disallow entrance of rainwater into the water-receiving channels. Albracht's as well as previous and succeeding similar inventions have therefore notably avoided the utilization of filter insertions. What may appear as a logical anticipation by such inventions at first glance, (inserting of a filter mesh or material into the channel), has been shown to be undesirable and ineffective across a broad spectrum of filtering materials: Employing insertable filters into such inventions has not been found to be a simple matter of anticipation, or design choice of filter medium by those skilled in the arts. Rather, it has proved to be an ineffective option, with any known filter medium, when attempted in the field. Such attempts, in the field, have demonstrated that the filter mediums will eventually require manual cleaning. German Patent 5,905,961 teaches a gutter protection system for preventing the entrance of debris into a rain gutter. The German patent teaches a gutter protection system to include a single continuous two sided well 7 with angled sides and perforated bottom shelf which rainwater will flow and empty into the rain gutter below. The well is recessed beneath and between two solid lateral same plane shelves close to the front of the system for water passage near and nearly level with the front top lip of the gutter. The well is of a depth, which is capable of receiving a filter mesh material. However, for the reasons described in the preceding paragraphs, an ability to attach a medium to an invention, not specifically designed to utilize such a medium, may not result in an effective anticipation by an invention. Rather, the result may be a diminishing of the invention and its improvements as is the case in Albracht's U.S. Pat. No. 5,557,891, the German Patent, and similar inventions employing recessed wells or channels between adjoining planes or curvatures. U.S. Pat. No. 5,595,027 to Vail teaches a continuous opening 24A between the two top shelves. Vail teaches a gutter protection system having a single continuous well 25, the well having a depth allowing insertion and retention of filter mesh material 26 (a top portion of the filler mesh material capable of being fully exposed at the holes). Vail does teach a gutter protection system designed to incorporate an insertable filter material into a recessed well. However, Vail notably names and intends the filter medium to be a tangled mesh fiberglass five times the thickness of the invention body. This type of filtration medium, also claimed in U.S. Pat. No. 4,841,686 to Rees, and in prior art currently marketed as FLOW-FREE. TM. is known to trap and hold debris within itself which, by design, most filter mediums are intended to do, i.e.: trap and hold debris. Vail's invention does initially prevent some debris from entering an underlying rain gutter but gradually becomes ineffective at channeling water into a rain gutter due to the propensity of their claimed filter mediums to clog with debris. Though Vail's invention embodies an insertable filter, such filter is not readily accessible for cleaning when such cleaning is necessitated. The gutter cover must be removed and uplifted for cleaning and, the filter medium is not easily and readily inserted replaced into its longitudinal containing channel extending three or more feet. It is often noted, in the field, that these and similar inventions hold fast pine needles in great numbers which presents an unsightly appearance as well as create debris dams behind the upwardly extended and trapped pine needles. Such filter meshes and non-woven lofty fiber mesh materials, even when composed of finer micro-porous materials, additionally tend to clog and fill with oak tassels and other smaller organic debris because they are not resting, by design, on a skeletal structure that encourages greater water flow through its overlying filter membrane than exists when such filter meshes or membranes contact planar continuously-connected surfaces. Known filter mediums of larger openings tend to trap and hold debris. Known filter mediums smaller openings clog or “heal over” with pollen and dirt that becomes embedded and remains in the finer micro-porous filter mediums. At present, there has not been found, as a matter of common knowledge or anticipation, an effective water-permeable, non-clogging “medium-of-choice” that can be chosen, in lieu of claimed or illustrated filter mediums in prior art, that is able to overcome the inherent tendencies of any known filter mediums to clog when applied to or inserted within the types of water receiving wells and channels noted in prior art. Vail also discloses that filter mesh material 26 is recessed beneath a planar surface that utilizes perforations in the plane to direct water to the filter medium beneath. Such perforated planar surfaces as utilized by Vail, by Sweers U.S. Pat. No. 5,555,680, by Morin U.S. Pat. No. 5,842,311 and by similar prior art are known to only be partially effective at channeling water downward through the open apertures rather than forward across the body of the invention and to the ground. This occurs because of the principal of water adhesion: rainwater tends to flow around perforations as much as downward through them, and miss the rain gutter entirely. Also, in observing perforated planes such as utilized by Vail and similar inventions (where rainwater experiences its first contact with a perforated plane) it is apparent that they present much surface area impervious to downward water flow disallowing such inventions from receiving much of the rainwater contacting them. A simple design choice or anticipation of multiplying the perforations can result in a weakened body subject to deformity when exposed to the weight of snow and/or debris or when, in the case of polymer bodies, exposed to summer temperatures and sunlight. U.S. Pat. No. 4,841,686 to Rees teaches an improvement for rain gutters comprising a filter attachment, which is constructed to fit over the open end of a gutter. The filter attachment comprised an elongated screen to the underside of which is clamped a fibrous material such as fiberglass. Rees teaches in the Background of The Invention that many devices, such as slotted or perforated metal sheets, or screens of wire or other material, or plastic foam, have been used in prior art to cover the open tops of gutters to filter out foreign material. He states that success with such devices has been limited because small debris and pine needles still may enter through them into a rain gutter and clog its downspout opening and or lodge in and clog the devices themselves. Rees teaches that his use of a finer opening tangled fiberglass filter sandwiched between two lateral screens will eliminate such clogging of the device by smaller debris. However, in practice it is known that such devices as is disclosed by Rees are only partially effective at shedding debris while channeling rainwater into an underlying gutter. Shingle oil leaching off of certain roof coverings, pollen, dust, dirt, and other fine debris are known to “heal over” such devices clogging and/or effectively “water-proofing” them and necessitate the manual cleaning they seek to eliminate. (If not because of the larger debris, because of the fine debris and pollutants). Additionally, again as with other prior art that seeks to employ filter medium screening of debris; the filter medium utilized by Rees rests on an inter-connected planar surface which provides non-broken continuous paths over and under which water will flow, by means of water adhesion, to the front of a gutter and spill to the ground rather than drop downward into an underlying rain gutter. Whether filter medium is “sandwiched” between perforated planes or screens as in Rees' invention, or such filter medium exists below perforated planes or screens and is contained in a well or channel, water will tend to flow forward along continuous paths through cur as well as downward into an underlying rain gutter achieving less than desirable water-channeling into a rain gutter. U.S. Pat. No. 5,956,904 to Gentry teaches a first fine screen having mesh openings affixed to an underlying screen of larger openings. Both screens are elastically deformable to permit a user to compress the invention for insertion into a rain gutter. Gentry, as Rees, recognizes the inability of prior art to prevent entrance of finer debris into a rain gutter, and Gentry, as Rees, relies on a much finer screen mesh than is employed by prior art to achieve prevention of finer debris entrance into a rain gutter. In both the Gentry and Rees prior art, and their improvements over less effective filter mediums of previous prior art, it becomes apparent that anticipation of improved filter medium or configurations is not viewed as a matter of simple anticipation of prior art which has, or could, employ filter medium. It becomes apparent that improved filtering methods may be viewed as patenable unique inventions in and of themselves and not necessarily an anticipation or matter of design choice of a better filter medium or method being applied to or substituted within prior art that does or could employ filter medium. However, though Rees and Gentry did achieve finer filtration over filter medium utilized in prior art, their inventions also exhibit a tendency to channel water past an underlying gutter and/or to heal over with finer dirt, pollen, and other pollutants and clog thereby requiring manual cleaning. Additionally, when filter medium is applied to or rested upon planar perforated or screen meshed surfaces, there is a notable tendency for the underlying perforated plane or screen to channel water past the gutter where it will then spill to the ground. It has also been noted that prior art listed herein exhibits a tendency to allow filter cloth mediums to sag into the opening of their underlying supporting structures. To compensate for forward channeling of water, prior art embodies open aperatures spaced too distantly, or allows the aperatures themselvs to encompass too large an area, thereby allowing the sagging of overlying filter membranes and cloths. Such sagging creates pockets wherein debris tends to settle and enmesh. U.S. Pat. No. 3,855,132 to Dugan teaches a porous solid material which is installed in the gutter to form an upper barrier surface (against debris entrance into a rain gutter). Though Dugan anticipates that any debris gathered on the upper barrier surface will dry and blow away, that is not always the case with this or similar devices. In practice, such devices are known to “heal over” with pollen, oil, and other pollutants and effectively waterproof or clog the device rendering it ineffective in that they prevent both debris and water from entering a rain gutter. Pollen may actually cement debris to the top surface of such devices and fail to allow wash-off even after repeated rains. U.S. Pat. No. 4,949,514 to Weller sought to present more water receiving top surface of a similar solid porous device by undulating the top surface but, in fact, effectively created debris “traps” with the peak and valley undulation. As with other prior art, such devices may work effectively for a period of time but tend to eventually channel water past a rain gutter, due to eventual clogging of the device itself. There are several commercial filtering products designed to prevent foreign matter buildup in gutters. For example the FLOW-FREE .TM gutter protection system sold by DCI of Clifton Heights, Pa. Comprises a 0.75-inch thick nylon mesh material designed to fit within 5-inch K type gutters to seal the gutters and downspout systems from debris and snow buildup. The FLOW-FREE. TM device fits over the hanging brackets of the gutters and one side extends to the bottom of the gutter to prevent the collapse into the gutter. However, as in other filtering attempts, shingle material and pine needles can become trapped in the coarse nylon mesh and must be periodically cleaned. U.S. Pat. No. 6,134,843 to Tregear teaches a gutter device that has an elongated matting having a plurality of open cones arranged in transverse and longitudinal rows, the base of the cones defining a lower first plane and the apexes of the cones defining an upper second plane. Although the Tregear device overcomes the eventual trapping of larger debris within a filtering mesh composed of fabric sufficiently smooth to prevent the trapping of debris he notes in prior art, the Tregear device tends to eventually allow pollen, oil which may leach from asphalt shingles, oak tassels, and finer seeds and debris to coat and heal over a top-most matting screen it employs to disallow larger debris from becoming entangled in the larger aperatured filtering medium it covers. Tregear indicates that filtered configurations such as a commercially available attic ventilation system known as Roll Vent.RTM. manufactured by Benjamin Obdyke, Inc. Warminster, Pa. Is suitable, with modifications that accomadate its fitting into a raingutter. However, such a device has been noted, even in its original intended application, to require cleaning (as do most attic screens and filters) to remove dust, dirt, and pollen that combine with moisture to form adhesive coatings that can scum or heal over such attic filters. Filtering mediums (exhibiting tightly woven, knitted, or tangled mesh threads to achieve density or “smoothness”) employed by Tregear and other prior art have been unable to achieve imperviousness to waterproofing and clogging effects caused by a healing or pasting over of such surfaces by pollen, fine dirt, scum, oils, and air and water pollutants. Additionally, referring again to Tregear's device, a lower first plane tends to channel water toward the front lip of a rain gutter, rather than allowing it's free passage downward, and allow the feeding and spilling of water up and over the front lip of a rain gutter by means of water-adhesion channels created in the lower first plane. Prior art has employed filter cloths over underlying mesh, screens, cones, longitudinal rods, however such prior art has eventually been realized as unable to prevent an eventual clogging of their finer filtering membranes by pollen, dirt, oak tassels, and finer debris. Such prior art has been noted to succumb to eventual clogging by the healing over of debris which adheres itself to surfaces when intermingled with organic oils, oily pollen, and shingle oil that act as an adhesive. The hoped for cleaning of leaves, pine needles, seed pods and other debris by water flow or wind, envisioned by Tregear and other prior art, is often not realized due to their adherence to surfaces by pollen, oils, pollutants, and silica dusts and water mists. The cleaning of adhesive oils, fine dirt, and particularly of the scum and paste formed by pollen and silica dust (common in many soil types) by flowing water or wind is almost never realized in prior art. Prior art that has relied on reverse curved surfaces channeling water inside a rain gutter due to surface tension, of varied configurations and pluralities, arranged longitudinally, have been noted to lose their surface tension feature as pollen, oil, scum, Eventually adhere to them. Additionally, multi-channeled embodiments of longitudinal reverse curve prior art have been noted to allow their water receiving channels to become packed with pine needles, oak tassels, other debris, and eventually clog disallowing the free passage of water into a rain gutter. Examples of such prior art are seen in the commercial product GUTTER HELMET.RTM. manufactured by American metal products and sold by Mr. Fix It of Richmond, Va. In this and similar Commercial products, dirt and mildew build up on the bull-nose of the curve preventing water from entering the gutter. Also ENGLERT'S LEAFGUARD. RTM. Manufactured and distributed by Englert Inc. of Perthamboy N.J. and K-GUARD. RTM. Manufactured and distributed by KNUDSON INC. of Colorado are similarly noted to lose their water-channeling properties due to dirt buildup. These commercial products state such, in literature to homeowners that advises them on the proper method of cleaning and maintaining their products. None of theses above-described systems keep all debris out of a gutter system allowing water alone to enter, for an extended length of time. Some allow lodging and embedding of pine needles and other debris is able to occur within their open water receiving areas causing them to channel water past a rain gutter. Others allow such debris to enter and clog a rain gutter's downspout opening. Still others, particularly those employing filter membranes, succumb to a paste and or scum-like healing over and clogging of their filtration membranes over time rendering them unable to channel water into a rain gutter. Pollen and silica dirt, particularly, are noted to cement even larger debris to the filter, screen, mesh, perforated opening, and/or reverse curved surfaces of prior art, adhering debris to prior art in a manner that was not envisioned. Accordingly, it is an object of the present invention to provide a gutter shield that permits drainage of water runoff into the gutter trench without debris becoming entrenched or embedded within the surface of the device itself and that employs a filtration membrane configuration that possesses sufficient self-cleaning properties that prevent the buildup of scum, oil, dirt, pollen, and pollutants that necessitate eventual manual cleaning as is almost always the case with prior art. Another object of the present invention is to provide a gutter shield that employs a filtration membrane that is readily accessible and easily replaceable if such membrane is damaged by nature or accident. Another object of the present invention is to provide a gutter shield that better enhances the cosmetic appearance and blending of and with a building's rain gutter system than is offered by prior art. Another object of the present invention is to provide a gutter shield that will accept more water run-off into a five inch K-style rain gutter than such a gutter's downspout opening is able to drain before allowing the rain gutter to overflow (in instances where a single three-inch by five-inch downspout is installed to service 600 square feet of roofing surface). Other objects will appear hereinafter. SUMMARY It has now been discovered that the above and other objects of the present inventioin may be accomplished in the following manner. Specifically, the present invention provides a gutter shield for use with gutters having an elongated opening. Normally the gutters are attached to or suspended from a building. The gutter shield device comprises an extruded polymer uni-body of an angled first plane that rests on the front lip of a rain gutter and that adjoins a second downwardly angled perforated plane by means of a u-shaped channel that exists on the underside of the rear edge of said first plane. A second plane then joins to an upward vertical support leg that joins to a third perforated plane that angles downward (referenced to the rear wall of an underlying rain gutter) and inward toward the vertical leg. Second and third perforated planes thereby exibit an extended v-shaped configuration that directs water to the inward center of a rain gutter where it is then dammed by a vertical support leg that forces the water to pool upward and drop through perforations rather than channel past them. A fourth upwardly angled plane positioned above an behind the v-shaped configuration of planes two and three, joins to plane three by means of a u-shaped channel and vertical leg, joined to and beneath the forward edge of the u-shaped channel, that exists underside the forward (referenced to the front lip of a rain gutter) edge of plane four. The fourth plane has embedded in the center of its upper surface, a recessed channel to facilitate scoring and braking of the fourth plane. The fourth plane then joins to a rear vertical leg by means of a rear u-shaped channel. A filtration configuration is inserted in the extruded body of the gutter sheild device. The upper membrane of the filter configuration is comprised of smaller threads intersecting or adjoing larger ones at centermost points on the sides of the larger threads. The upper membrane thereby avoids presenting overlapping or underlapping thread joints that tend to trap and hold debris, while presenting a very water permeable surface that more readily lends itself to self-cleaning by way of flowing water. The upper membrane is sewn to the edges of an underlying skeletal structure that exhibits a strong siphoning action. The lower supporting skeletal structure beneath the upper membrane is comprised of ellipses spaced approximately 0.19 inch from end to end that have underlying vertical legs that join, at their lowest point, to a horizontal perforated surface that has underlying vertical extending legs. This combination of multiple elliptical surfaces so spaced, and of vertical planes above and beneath a perforated horizontal plane, exhibits strong tendencies to break forward water channeling, that often causes water to spill past a rain gutter, and redirect water downward and inward into an underlying rain gutter. The gutter sheild body may be inserted into and secured in a rain gutter by common methods now recognized as public domain. The filtration configuration is pinched on each lateral edge and then the edges are realeased into u-shaped edge receiving channels. The filtration configuration is supported in its center by an upward extending vertical leg that adjoins perforated planes two and three at their lowest edges. OBJECTS AND ADVANTAGES An object of the present invention is to provide a gutter shield device that employs a fine filtration combination that is not subject to gumming or healing over by pollen, silica dust, oils, and other very fine debris. Another object of the present invention is to provide a gutter shield body that can quickly and easily, in the field at the time of installation, be retrofitted with the current gutter coil employed in extruding the raingutters the present invention would be installed in. Another object of the present invention is to provide a filtration membrane that is not affixed to an underlying surface by adhesive means that tend to gum and trap debris in hot weather. Another object of the present invention is to provide a filtration configuration that does not allow its filter cloth or membrane to sag and develop debris catching pockets. Another object of the present invention is to provide a gutter shield device that disallows the entrance of debris into a raingutter in the event its removable filter requires replacement due to storm damage. Another object of the present invention is to provide a filtration configuration and encompassing body that eliminates any forward channeling of rain water. Another object of the present invention is to provide a filtration configuration that may more readily be inseted into or removed, if required, than has been realized in prior art. THE DRAWING FIG. 1 . is a partial or fragmentary sectional edge view of the present invention displaying the profile of the main body of the gutter cover as it would appear extruding from a die. FIG. 2 . is a partial or fragmentary top perspective view of the main body of the present invention. FIG. 3 . is a partial or fragmentary sectional edge view of a component of the present invention displaying the profile of a supporting skeletal filtration structure that is an insertable component employed by the present invention. FIG. 4 . is a partial or fragmentary top perspective view of the supporting skeletal filtration component employed by the present invention. FIG. 5 . is an enlarged isolated view of a filter medium which affixes to the supporting filtration skeleton component employed by the present invention. FIG. 6 . is a partial or fragmentary top perspective view of the completed filtering component of the present invention as it appears prior to insertion into a receiving channel of the main body of the present invention. FIG. 7 . is a partial or fragmentary sectional edge view of the present invention displaying the profiles of it's main body with filtration skeleton inserted. FIG. 8 . is a partial or fragmentary top perspective view of the preferred embodiment of the present invention displaying the main body of the gutter cover with inserted filtration skeleton and affixed (to the skeleton) filter medium. FIG. 9 . is a partial or fragmentary sectional view displaying the profiles of a roofline portion of a building structure, and shows an end view of a sectioned K-style gutter and a side or end view of an overlying and attached gutter cover section. FIG. 9 a . is a partial or fragmentary sectional view displaying the profiles of a roofline portion of a building structure, K-style gutter, attached gutter cover, and optional rear insertable filter medium. FIG. 10 . is a partial or fragmentary sectional view displaying the profiles of a roofline portion of a building structure, K-style gutter, attached gutter cover, and optional securing ledge. FIG. 11 . is a partial or fragmentary sectional view displaying the profiles of a roofline portion of a building structure, K-style gutter, attached gutter cover, and optional rear extension component. FIG. 11 a . is a partial or fragmentary top perspective view of an optional rear extension component of the present invention. FIG. 12 . is a partial or fragmentary top perspective view of the main body of the present invention and of an optional covering sleeve component. FIG. 12 a . is a partial or fragmentary top perspective view of the main body of the present invention and of an optional covering sleeve component slid onto the top shelf of the main body of the present invention. FIG. 13 . displays top perspective views of the main body of the present invention illustrating an optional width-adjustable element or feature of the gutter cover. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now specifically to the drawings, a gutter cover (protector) body 1 with an insertable “multi-level filter” 32 according to the present invention is illustrated in FIG. 8 . The gutter protector material is to be a polymer that is reduced to liquid form through screw compression of plastic “tags” or reduced to liquid form through other means. This liquid plastic mixture will then be extruded through a single block die embodying a profile of the body of the invention. The extruded material is rigid or semi-flexible PVC or Polypropylene or other heat, chemical, and UV resistant polymer. The preferred thickness of the extruded polymer material forming the gutter protector cover will range from 0.05 to 0.07 inches. The extruded material is suitably thick to maintain its shape and not deform or dip under load bearing weight of snow and ice or deform when exposed to high ambient temperatures which have caused prior art of lesser polymer thickness to deform vertically upwards and downwards allowing open-air gaps to form from one piece of prior art to the next when they rest abutted side by side. These gaps may allow debris entrance into a rain gutter. The PVC, Polypropylene, or other polymer will contain sufficient titanium oxide, carbon black, or other UV inhibitors to resist breakdown of structural integrity for a period of at least 10 years when exposed to normal cycles of “Florida Sun” (sunlight equivalent to that experienced over a 10 year period of outdoor exposure to weathering conditions in the state of Florida). The gutter protector body may be extruded in any length but it is preferred that the extruded body be cut into 4 to five foot lengths, at the point of manufacture, while exiting a plastics extrusion cooling tray. Such lengths may be installed by one individual while allowing for as few joints or seams as possible to exist when the present invention is installed over the length of a gutter. The extruded body is 5.4 inches wide. Referring to FIG. 10 it is illustrated that the extruded body will rest inside the topmost opening of a conventional K-style 5 or 6 inch rain gutter 33 supported by spikes or “hidden hangars” 28 upon which the rear horizontal leg of the body 20 rests and supported by the front lip of the K-style rain gutter upon which the front “lip” 9 of the extruded body rests, such front lip 9 having an approximate length of 0.757 in. FIG. 10 further illustrates the body may also be supported in the rear by affixing a flexible semi-concaved metal or plastic extrusion 27 (0.07 inches thickness or less) into the fascia board of a building structure and allowing it to extend outward away from the fascia board sufficient length to enable semi-concaved extrusion 27 to insert into the rear Channel 22 of the body to support the body at the rear. This may be desirable to ensure high winds may not uplift the extruded gutter cover out of the rain gutter as does occur with prior art. This may also ensure a level plane is created from one five length of the extruded body to the next at the rear in instances where reliance on gutter spikes for support of the rear portion of the extruded body may be inadvisable in instances where the gutter spikes may be driven at uneven heights through the rear of a rain gutter into a fascia board disallowing the extruded gutter cover 1 from maintaining a level horizontal plane between adjoining (abutted) pieces. A level plane from one gutter cover 1 to the next when installed inside a rain gutter is important to disallow vertical gaps from occurring between pieces as they may in prior art which may provide an entrance for debris into a rain gutter. The profile of the body of the gutter protector illustrated in FIG. 1 shows the extruded body includes a rear horizontal leg 20 approximately 0.4 inches in length which may serve to rest on a gutter spike or hidden gutter hangar for a length of at least 0.4 inches at point of contact which serves to distribute any weight upon the gutter cover body over a greater surface area of a supporting spike or hanger than a simple extension of rear leg 19 , whose approximate length is 0.6 in., would provide in the absence of rear horizontal leg 20 . FIG. 2 reference numeral 20 illustrates that a rear horizontal leg of the extruded body 1 is integral to the body and extends the entire length of the body and is perforated to allow rear drainage surface area in the event wind blown rain or melting ice flows rearward rather than forward into filtration membrane 32 . FIG. 9 illustrates that rear horizontal leg 20 also may serve as a locking mechanism due to its positioning beneath hex-head or other screw fasteners 30 used to secure a hidden hangar and rear of a rain gutter to a fascia board in such instances when hidden hangars are the chosen method of fastening. It can be seen in FIG. 9 a that rear horizontal leg 20 may also serve as a platform on which a mesh or other type filter 31 approximately ¾ inch to 1½ inch wide and one inch tall may rest to provide a rear barrier to debris that may possible be wind blown to the rear of the gutter protector body. Referring, again, to FIG. 1 it can be seen that the extruded gutter cover body includes a rear support leg 19 that serves to provide rear vertical support for the gutter cover body and which includes “score lines” 21 which an installer may score with a utility knife or other scoring device if necessary. Such scoring will prevent running cracks up the rear support leg 19 from occurring if the rear support leg should ever need to be notched out to fit over a gutter spike that may be positioned too high through or above the rear of a rain gutter. In practice, in the field, improper positioning of the gutter spike occurs infrequently and may cause the gutter cover body to rest unevenly at varying heights inside the rain gutter necessitating that the rear support leg 19 and rear horizontal leg 20 be notched out to allow the rear of the gutter cover body to rest in a lower position inside the rain gutter to maintain an attractive low profile and smooth even-plane transition from section to section of the body of the present invention. Referring again to FIG. 1, rear support leg 19 of the extruded body extends vertically upwards at an approximate 85-degree angle and an approximate 0.6-inch length. Support leg 19 then bends forward at approximately a 75 degree to 95-degree angle to form a shelf 23 approximately 0.2 inches in length. Shelf 23 extends upward approximately 90 degrees forming vertical leg 18 with an approximate length of 0.21 inches. Vertical leg 18 then angles forward approximately 90 degrees into a higher shelf 17 whose approximate length is 0.3 inches. Referring now to FIG. 10 it is seen that bottom shelf 23 , vertical leg 18 , and higher shelf 17 of the extruded body form a recessed “receiving” channel 22 approximately 0.2 inches in depth and 0.07 inches wide which may serve to receive plastic or metal inserts or fasteners 27 that may be used to create a rear to forward tension mount of the extruded body. Referring now to FIGS. 12 and 12 a , it is illustrated that channel 22 may additionally may serve to act as a the first of two receiving channels of the extruded body, the second receiving channel being channel 23 that may receive and hold fast and permanently an aluminum, zinc, or copper metal cover 35 that may be clipped onto the extruded body. This clipped on cover 35 may serve to join two extruded body pieces together by spanning and covering the joint formed at their side-by-side abutment when such pieces are installed in a rain gutter. This clipped on cover 35 may further serve to provide fungicidal properties when made of zinc that would discourage moss mold or mildew growth on the invention, which is an improvement, not found in prior art. The clipped on cover 35 may further serve to allow color and material matching of the plastic extruded body to aluminum, copper, and other metal rain gutters which is an advantage and property not found or suggested in prior art. The co-use of two such materials, polymer and metal, in a leaf guard on copper or other expensive metal rain gutters would provide a great economical alternative to the use of solid copper leaf guards which naturally employ thicker and thereby more expensive copper in their design. The dimensions of such an extruded 0.019 or thinner metal cover would be such that it's underside 36 would be approximately 5 percent to 15 percent greater than the exterior portion of the extruded plastic body of the invention it covers. Such extruded metal cover may also serve to act as an extension for the plastic extruded body it covers to allow for a fit rain gutters larger than standard 5″ K style gutters by widening the clip on metal shelf 35 to accommodate 6 inch or wider rain gutters. Referring again to FIG. 1, shelf 17 extends horizontally 0.3 in. and then upward into a curve 2 a such curve having an exterior radius of approximately 0.137 and an interior radius of approximately 0.073 inch. The reverse of curve 2 a of the extruded body extends forward in a somewhat horizontal plane 2 angled downward approximately 5 degrees for a distance of approximately 1.5 to 1.75 inches. Horizontal plane 2 embodies a small recessed channel 59 across its entire length of sufficient depth to allow for scoring and breaking of the horizontal plane. FIG. 13 illustrates such scoring and breaking of recessed channel 59 may be optionally employed by the installer in instances where a horizontally compressed rain gutter does not allow for easy installation of the invention: the severed rear portion of the extruded body 36 may then be placed over the front severed portion of the extruded body 37 as illustrated in FIG. 13 and affixed by polymer cement or fasteners such as plastic bolt 38 and plastic nut 39 creating such overlap distance of the rear severed portion of the extruded body over the front severed extrusion of the severed body as the installer deems necessary to create an ideal adjusted extruded body width for placement in a horizontally compressed portion of a rain gutter. Referring again to FIG. 1, Horizontal plane 2 , after extending a distance of approximately 1.5 inches, will then “fork” into two extensions: one extension; 3 , continues to extend outward angled downward from the 1.5 inch point an additional 5 to 10 degrees to form a top shelf approximately 0.28 inch in length. The other extension 4 of Horizontal plane 2 extends downward at an approximate 85 degree angle for a distance of 0.125 inches and then angles forward 90 degrees into a plane 16 approximately 0.28 inches in length. Extension 3 extension 4 and plane 16 form a recessed “receiving” channel 24 with a depth of approximately 0.28 inch and a width 55 of approximately 0.125 inch which serves to secure the edge of the multi level filter portion of the invention and to receive, if opted for, the curved edge of a metal cover which may be clipped onto Curve 2 a , Horizontal plane 2 , and extension 3 as illustrated in FIG. 12 a. Referring again to FIG. 1; Plane 16 of the extruded body continues and then angles sharply downward at an approximate 80 to 85 degree angle for a distance of approximately 0.4 inches to form plane 5 . Plane 5 extends downward and then angles forward at an approximate 22-degree angle-forming plane 15 . Plane 15 has an approximate length of 0.94 inch and is perforated as illustrated in FIG. 2 with perforations 0 approximately 0.065 inch wide, 0.125 long. Perforations 0 are aligned end-to-end and spaced approximately ¼ inch apart in rows, which extend the length of the extruded body, such rows being spaced approximately 0.145 inch apart. Referring again to FIG. 1, Plane 15 forks into an extension and a continuance: the extension of plane 15 is plane 6 which extends upwards as an extension of plane 15 at an approximate 90 degree angle. Plane 6 will act as a support for the insertable filter portion of the invention and presents an improvement not found in prior art in that it will act as a dam that forces water to back up and drip through the rear most rows of perforations of plane 15 rather than continue forward with enough speed and depth of water flow to spill over the front lip of the rain gutter. Such occurrence of water spill is common in prior art, which relies solely on water adhesion principals. Planes 5 , 15 , and 6 of the extruded body form a water receiving well with a perforated bottom shelf 15 that will direct water into a rain gutter when acting in conjunction with the water dam formed by plane 6 as described in the preceding sentence. Referring again to FIG. 1, Plane 15 , in addition to forking upwards into plane 6 also continues on at an approximate 22 degree upward angle beginning at the base of Plane 6 and extends into a perforated plane 13 approximately 0.95 inch long. This angling upward of plane 13 toward the front lip of the gutter presents an improvement not found in prior art in that water which contacts plane 13 will not continue on a forward flow toward the top front lip of a rain gutter due to water adhesion principals where it may then spill outside the rain gutter. Instead, the water that contacts plane 13 will follow the downward angling plane 13 and be more surely and intentionally directed into a rain gutter. The perforations of plane 13 are identical to those of plane 15 : 0.065 inch wide, 0.125 long, each perforation spaced end to end approximately 0.25 inches aligned in rows the length of the extruded body such rows being spaced approximately 0.145 inch apart. Plane 13 extends forward approximate 0.95 in and then angles downward approximately 16 degrees into plane 12 . Plane 12 extends forward approximately 0.33 inch at which point it forks into an extension and a continuance: the extension, plane 7 forks upward at an approximate 80 degree angle for a distance of approximately 0.14 inch at which point plane 7 terminates in a “T” configuration. The “T” configuration has a rearward (toward the rear of the extruded body) horizontally extending section, plane 8 , having a length of approximately 0.25 inch. Receiving channel 24 a is formed by planes 12 , 7 , and 8 and such channel has an approximate width 56 of 0.125 inch. This channel acts to receive and secure the forward edge 54 of supporting skeletal filter component 57 as illustrated in FIG. 8 . The forward extension of the “T” is an extending plane, 9 , that angles approximately 7 degrees downward for a distance of approximately 0.757 inch where it then angles downward 45 degrees into plane 10 , which measures approximately 0.45 inch in length. The continuance of plane 12 is for a distance of approximately 0.24 inches after its vertical fork; plane 7 giving plane 12 a total length of 0.57 inch. Referring again to FIG. 1 it may be seen that planes 6 , 13 , 12 , 7 , and 8 form a receiving well of the extruded body which will direct rain water through its perforations into a rain gutter. FIG. 1, planes 12 , 7 , and 8 further illustrate a recessed receiving channel 24 that may receive and secure both an inserted edge of the multi filter employed by the invention as is illustrated in FIG. 7 and FIG. 8 . FIG. 12 a illustrates that a “clip on” metal cover 40 may be inserted over planes 8 , 9 , and 10 to achieve an optional aesthetic matching of colored aluminum or copper between the present invention and the underlying gutter it protects and/or to achieve the improvements previously described in the last sentence of page 4 and the fist sentence of page 5 of this disclosure. FIG. 11 illustrates Channel 22 may serve as a receiving channel for polymer, metal, or other semi-flexible formed or extruded inserts with profiles similar to extension 41 which may be placed or affixed with adhesives into Channel 22 and may then serve as an extension of the extruded body 1 which extends rearward and compresses against the rear wall of a rain gutter, hidden hangar, or fascia board to create a rear to forward tension mount of the extruded body into the rain gutter at the discretion of the installer. The amount of mounting tension created may be varied by the length of the top shelf 42 of the extruded or formed extension 41 . Referring now to FIG. 3 there is illustrated the profile of a perforated filter skeleton 43 . The width of filter skeleton 43 is approximately 2.5 inches and is an extruded polymer of approximately 0.04 to 0.06 inches. Plane 44 is approximately 0.58 inch and contains perforations 0 , such perforations being of elliptical shape approximately 0.45 inches long and 0.22 inch wide. The perforations 0 are positioned as close to vertical leg 45 as possible and have a wider top opening than bottom creating a taper which more readily captures and directs rain water than a simple straight through punch. Horizontal plane 44 t-junctions into vertical leg 45 whose approximate length is 0.35 inch. Leg 45 has a curved bottom 46 , such curved surface facilitating the dropping of water off of leg 45 downward into the rain gutter. Leg 45 is capped by ellipse 47 . Ellipse 47 has dimensions of approximately 0.13 inch width and 0.08 inch height. The elliptical curved surfaces 47 resting on vertical legs 45 , create water-channeling paths that exhibit siphoning effects stronger than has been realized in prior art. These “t” configurations, as well as their approximate spacing of 0.19 inch from subsequent ellipses and legs, create act as an ideal support for warp-knitted filter membrane 50 (shown in FIG. 5 in an exploded view): Such “t” configurations, and their spacing, enhance the self-cleaning properties inherent in filter membrane 50 . Additionally, they present a breaking of any water channeling paths to the front of a rain gutter lip noted in prior art. FIG. 6 illustrates that filter membrane 50 will be affixed to filter skeleton 43 . The downward curves and spacing of the ellipses 47 offer an improvement over prior art in creating multiple curved surface water channels that direct toward a vertical leg resting on a horizontal perforated plane that employs downward extending legs to continue the flow of water downward rather than forward. This configuration creates stronger siphoning action than is created in prior art relying on elliptical ocean-wave shapes to channel water or downward extrusions positioned beneath perforations or screens. The channeling of water almost fully around an ellipse that is broken by a vertical downward extending leg better captures water and directs it downward preventing back-flow of received water against incoming water noted in prior art. Vertical legs 45 downward extensions beneath planes 44 and 48 ensure the water adhesion of flowing rain water is broken at the most opportune moment to ensure the directed flow of water into a rain gutter. Perforated planes 48 are approximately 0.25 inches in width. Viewing from right to left, the extruded filter skeleton continues from the first vertical leg 45 whose length is approximately 0.35 inch into an upward extension where it terminates into an ellipse 47 . Vertical leg 45 is intersected approximately 0.2 inch down by forward extending perforated horizontal plane 48 . Planes 48 are approximately 0.25 inches in length. Perforated plane 48 continues forward until it intersects the second vertical leg 45 approximately 0.2 inch below ellipse 47 . Vertical leg 45 extends approximately 0.22 inch downward from perforated plane 48 in order to break any surface tension of water adhering to perforated plane 48 and redirect it downward into a rain gutter. A second perforated plane 48 extends forward horizontally from a second vertical leg 45 until it intersects a third vertical leg 45 . Third vertical leg 45 is capped by an ellipse 47 as are all vertical legs of filter skeleton 43 . A third perforated plane 48 extends forward horizontally from third vertical leg 45 until it intersects a vertical leg 51 whose length from ellipse 47 to it's lower most surface 46 is approximately 0.45 inch. A fourth perforated plane 48 extends forward horizontally from vertical leg 51 for a distance of approximately 0.25 inch where it then right angles upward into a vertical leg 54 whose approximate length is 0.2 inch. Vertical leg 54 extends upward into an ellipse 47 . Directly beneath the ellipse which caps vertical leg 54 , a horizontal perforated plane 55 extends forward for a distance of approximately 0.45 inch. Planes 44 and 52 each have the endmost section of their length non-perforated to allow space for a sewing seam. filter membrane 50 will be sewn onto filter skeleton 43 at these endmost sections of planes 44 and 52 . Referring to FIG. 3 and viewing supporting skeletal component 57 left to right: each combination left to right of ellipse 47 , vertical leg 54 , perforated plane 48 , vertical leg 51 , ellipse 47 and of ellipse 47 , vertical leg 51 , perforated plane 48 , vertical leg 45 , ellipse 47 and of ellipse 47 , vertical leg 45 , perforated plane 48 , vertical leg 45 , ellipse 47 creates water receiving wells whose components (by means of their structural configuration and spacing) act to slow the flow of rainwater as well as capture and direct rain water downward into a rain gutter in an improved manner over prior art. It can be seen in FIGS. 3 and 4, that planes 44 and 52 are positioned on higher planes than planes 48 . This is done to allow the top of the elliptical planes 47 to remain on a level or slightly recessed plane with planes 3 and 8 of the extruded body as illustrated in FIG. 11 . This will disallow a damming effect that could lead to debris build up behind the insertable filter and encourage debris to fall or be wind blown off of the invention. It can also be seen in FIG. 11 that, viewing from right to left, the third vertical leg 45 abuts the upward extending leg 6 of the extruded body. This feature discourages the product from shifting. Referring again to FIG. 3 it can be seen that, viewing from right to left, the forth leg 51 is of greater length than the preceding downward extending legs 45 . The length of leg 51 is approximately 0.48 inch. This illustrates that the length of legs may vary to prevent forward flow of water to the front of the gutter by decreasing water tension paths along the bottom of the filter membrane. The ellipses, too, may exist at different planes which would further facilitate the capturing of rainwater and the direction of it downward into the rain gutter. Referring again to FIG. 3 it is seen that vertical leg 54 does not extend beneath perforated plane 48 . The reason for this is illustrated in FIG. 7 where it is seen that extending vertical leg 54 beneath the plane 48 would cause the filter skeleton to rise above a level or slightly recessed plane than exists between 3 and 8 of the extruded body. An extension of vertical leg 54 beneath perforated plane 48 would cause it to contact plane 13 and push the filter skeleton upwards. The vertical height of vertical leg 54 is approximately 0.17 inches from its bottom most surface up to the point it contacts ellipse 47 . FIG. 5 is an exploded view of filter membrane 50 , the type of filtration fabric illustrated affixed to filter skeleton 43 as illustrated in FIG. 6 . It can be seen in FIG. 5 that small cylindrical threads of polymer extrusion 55 are made to pass through larger threads 56 . This unique method of fabric formation offers an improvement over prior art in that this configuration of smaller curved surfaces passing through, rather than woven or knitted above and beneath larger threads, increases the fabric's ability to capture and direct water. This method of fabric formation offers another improvement over prior art in that it encourages dirt and debris to be less likely to be retained by the fabric and therefore less likely to clog the filtration cloth than other filters employed in prior art: woven, weaved, knitted, non-woven lofty, are able to accomplish. The largest distance between any two larger threads is to be less than {fraction (8/100)} of an inch, which prevents the smallest of debris from lodging within an open (space between threads. The preferred embodiment of this invention is illustrated in FIG. 9 and FIG. 12 a .: An extruded polymer body with extruded multi level filter that employs water receiving channels framed by curved ellipses resting on vertical supporting, lower extending legs covered by a filtration cloth as illustrated in FIG. 5 and FIG. 6 with a slide on or clip on metal covers as illustrated in FIG. 12 a. Operation of the Main Embodiment Referring to FIG. 9, there is illustrated the present invention: a gutter protection system that consists of a main body 1 and an insertable filter skeleton 43 covered with a filter membrane 50 . Filter Membrane 50 is composed of intersecting threads. (An exploded view of the interconnecting structure of the threads is illustrated in FIG. 5 ). Referring to FIG. 10 The present invention is illustrated as inserted into the top water receiving opening of a k-style rain gutter 33 and resting on a gutter hangar 28 . It is illustrated that the present invention rests wholly beneath the sub roof 60 and roofing membrane 61 of a building structure. Referring to FIG. 12, it is illustrated that the present invention will be affixed to an existing rain gutter in two stages. First, a main body 1 will be placed inside the open top of a rain gutter and then may be secured in place by several means: Rear horizontal leg 20 will rest upon a hidden hangar 28 and prevent body 1 from displacing by locking beneath the head of fastening screw 30 . The front of the present invention is snapped into place and secured to the front lip of the k-style gutter by planes 9 , 7 , & 11 of the body. Sub-heading 1 Covering of Joints, Aligning of Adjoining Sections, and Color Matching Once this is accomplished, main body 1 offers improvement over prior art in offering a method of aligning adjoining sections of the invention in a manner that allows joints between adjoining body members to be covered. This covering of joints and joining of abutted sections of the invention is accomplished by means of a roll-formed or “braked” sleeve (see FIG. 12 and 12 a , sleeve 35 ). The resulting absence of debris-allowing joints is not realized in prior art intended to retrofit existing rain gutters. Referring FIG. 1, there is illustrated a recessed channel 22 . Recessed channel 22 acts as the first of two receiving wells 22 & 24 for a roll-formed or job-site “braked” metallic cover 35 which may be clipped onto the top shelf 2 of the present invention (see FIGS. 12 & 12 a ). This feature offers improvement over prior art in that no prior art offers the ability to specifically color match to it's underlying rain gutter at the time of installation. The present invention allows the installer to quickly break matching gutter coil to clip into and cover top shelf 2 and top shelf 9 as is illustrated in FIG. 12 a . Metallic sleeves 35 & 40 may also serve to further align each sectioned body of the present invention and maintain consistent edges and heights between adjoining bodies. This is an optimal method of ensuring consistency of height and edge alignment between adjacent sections not known in prior art. Sub-heading 2 Vertical Height and Horizontal Width Adjustments Another improvement achieved by the present invention, not known in prior art, is its ability to provide a means of extending body width to accommodate standard sized commercial sized gutters with 4, 5, 6, and 7 inch widths. Widening may be accomplished by breaking or rollforming the metal cover 35 (FIG. 12 a ) to a width wide enough to effectively extend the present invention's body rearward. Sub-heading 2a Vertical Adjustments In the event body 1 is installed in a rain gutter affixed to a fascia board by gutter spikes, the present invention offers an improvement not found in prior art by offering a quick, at-the-point-of-installation, method of adjusting the height of the body to ensure it remains consistent. The body 1 of the present invention offers improvement over prior art by allowing for adjustment of it's rear vertical leg 19 by scoring and breaking of the rear leg at points 21 . It is known gutter spikes, often employed to secure a rain gutter to a fascia board, are driven in and remain at uneven heights at the rear of the rain gutter. Prior art, which requires a supporting of a rear leg or rearward part of invention body, has not foreseen or allowed for simple height adjustments to be made, which would accommodate prior art bodies to supporting, gutter spikes. Such adjustments may be necessary to maintain a consistent level height of gutter protection units for cosmetic as well as functional reasons. The improvement accomplished by the present invention is that such height adjustment may be accomplished quickly at the point of installation with a simple blade (to score point 21 ) and pair of scissor snips to clip the rear leg structure from rear horizontal leg 20 up through rear vertical leg 19 to the scored recess 21 . The scored mark ensures that the portion of rear vertical leg 19 so scored and cut will break off easily. Prior art does not allow for such simple controlled height adjustment at the point of installation (possibly while the installer is on an extension ladder). Sub-heading 2b Width Adjustments The body 1 of the present invention offers another improvement over prior art designed to be inserted into the top of a rain gutter, rather than rest upon the top surface of a subroof or roofing membrane, such as U.S. Pat. No. 6,134,843 to Tregear, U.S. Pat. No. 5,619,825 to Leroney, etc,. by allowing for adjustment of the main body by means of a pre-scored recessed channel 59 (FIGS. 2 & 13 ). Scoring of channel 59 allows the clean breaking and refastening of the body 1 to achieve a means of adjusting the present invention to accommodate both 4 inch and 5 inch gutters. FIG. 13 illustrates that the body 1 of the present invention may broken, then rejoined in a fashion that creates shorter body widths to accommodate the varying widths of a single run of gutter length. It is known that lengths of installed gutter seldom maintain a consistent width due to irregularities in fascia boards they are attached to. Prior art such as is illustrated in U.S. Pat. No. 5,495,694 to Kuhns, U.S. Pat. No. 5,459,965 to Meckstroth, etc., that require a resting of their body on top of or directly beneath shingles or other roofing materials do not have an intrinsic ability to accommodate varying gutter widths. This leads to such prior art presenting an uneven appearance along their rear edges which varies with the uneven width of a gutter they are attached to. This unevenness of edges at the rear of such products, as well as the dipping of subroof structures that often occur beneath the shingles such prior art may rest upon or be affixed to, allows open air spaces to exist at the rear of such products or from side-edge to side-edge of adjoining pieces. Debris may then enter through into a rain gutter or become trapped in the open air spaces. Because this problem is known, installers of prior art are known to screw the rear of such products into their underlying supporting roof structure, which can present the potential for roof leaks and the voiding of roofing manufacture warranties. Prior art has offered limited adjustment of width, usually by relying on body tension to extend width, as illustrated in such prior art as U.S. Pat. No. 5,619,825 to Leroney, but such extension of body width found in prior art is meant only accommodate one gutter width i.e.: 5 inch or 6 inch and does not allow for utilization of prior art over a span of varying standard gutter widths. Added width of span accomplished by tension weakens the strength of such invention's affixture to the raingutter since the pressure of tension is weakened. Prior art does not allow for the shrinking or widening of body width offered by the present invention in such fashion as to allow installations on narrower gutter widths than 5 inch or as to allow consistently secure installations on wider gutter widths than 5 inch. Prior art that does allow for installation on varying standard gutter widths such as is found in U.S. Pat. No. 5,660,001 to Albracht and U.S. Pat. No. 5,640,8090 etc, is undesirable because of the required securing of such prior to or beneath roofing membranes, which has been found to cause failures of roofing membrane integrity. Sub-heading 3 Water Receiving Wells Referring again to FIG. 2 it is illustrated that the body 1 incorporates two recessed perforated planes 13 & 15 , separated by a vertical leg 6 . Both planes angle downward and inward into the body of an underlying raingutter. This allows the present invention to offer improvement over prior art as follows: Referring to FIG. 1 : there is illustrated two recessed water-receiving perforated wells 15 and 13 , which direct water, flow downward to a vertical leg 6 . The downward angle of perforated well 13 , away from the front lip 9 and front lip of a rain gutter offers improvement over prior art U.S. Pat. No. 5,595,027 to Vail, U.S. Pat. No. 5,956,904 to Gentry, U.S. Pat. No. 5,619,825 to Leroney, U.S. Pat. No. 4,841,686 to Rees, U.S. Pat. No. 6,134,843 to Tregear, and other prior art in that it forces water to cease any forward flow to the front of a rain gutter where it may spill past the raingutter as has been noted in prior art. Prior art has not effectively dealt with this noted problem. Reverse curved and hooded gutter protection methods such as U.S. Pat. No. 5,491,998 to Hansen do redirect water flow rearward into the raingutter but have not recognized the noted tendency of debris to follow the water around the curved surfaces they employ into the rain gutter as well. Additionally, such prior art is known to lose most of it's water adhesive properties over time as pollen, oil leaching from asphalt shingles, and other pollutants, coat and remain on the curved surfaces such prior art employs. Downward sloping plane 15 , also, prevents forward flow and resulting spilling of water to the ground, by acting in conjunction with vertical leg 6 . Vertical leg 6 , serves the dual purpose of acting as a center and downward water channeling support for the filtration membrane 50 and Skeleton 43 (See FIG. 9 ), and as serving as a dam that slows forward rushing water in recessed well 5 , 15 , 6 to slow and drain through the perforated plane 15 . Sub-heading 4 Filter Membrane and Skeleton Once installation and, if necessary, adjustment of the body and/or covering of the body 1 of the present invention is achieved, a filter membrane and skeleton will then be inserted into the recessed channel of the present invention. (See FIG. 2, then FIG. 8 and FIG. 9 ). Several improvements over prior art are offered by the filter membrane and skeleton employed by the present invention: Sub-heading 4a Filter Skeleton Referring now to FIG. 3 there is illustrated a filter member: a multi-level supporting structure upon which a wire or cloth membrane composed of intersecting threads shall rest. Prior art employing filtration cloth or membrane, which rests over open apertures e.g.: U.S. Pat. No. 5,595,027 to Vail, U.S. Pat. No. 5,956,904 to Gentry, U.S. Pat. No. 5,619,825 to Leroney, U.S. Pat. No. 4,841,686 to Rees, U.S. Pat. No. 6,134,843 to Tregear, etc. exhibits a property of preventing rainwater from entering the open apertures beneath the filtration cloth. In practice, in the field, it is often observed that volumes of water will travel around the underlying perforations, beneath the filter cloth or membrane covering them, due to water adhesion principals. The water will then feed toward the front of prior art, rather down beneath it and into a rain gutter, and will flow past the top front lip of a rain gutter. This common occurrence in prior art occurs for several reasons. Perforated surfaces existing in a single plane, such as is employed in U.S. Pat. No 5,595,027 to Vail, or as exists in the Commercial Product SHEERFLOW. RTM. Manufactured by L. B. Plastics of N.C., and similar prior art tend to channel water inventions sought to correct this undesirable property by either tapering the rim of the open perforation and/or creating downward extensions of the perforation (creating a water channeling path down through open air space) as exhibited in prior art U.S. Pat. No. 6,151,837 to Ealer, or by creating dams on the plane the perforations exist on, as exhibited in prior art U.S. Pat. No. 4,727,689 to Bosler. Such prior art has been unable to ensure all water would channel into the underlying rain gutter because the water, that did, indeed, travel through the open apertures on the top side of these types of perforated planes or screens, would also travel along the underside of the screen wires or perforated planes, as it had on top of these surfaces, and still continue it's undesirable flow to the front of the invention and front lip of the underlying rain gutter, due to water adhesion. Additionally, this “underflow” of water on the underside of the perforated planes and screens illustrated in prior art exhibits a tendency to “back flow” or attempt to flow upwards through the perforations inhibiting downward flow of water. This phenomenon has been noted in practice, in the field when it has been observed that open air apertures appear filled with water while accomplishing no downward flow of water into the underlying rain gutter. Other inventors sought to eliminate this undesirable property by employing linear rods with complete open air space existing between each rod, This method of channeling more of the water into the rain gutter exhibits more success on the top surface of such inventions, but it fails to eliminate the “under channeling” of rainwater toward the front of the invention due to the propensity of water to follow the unbroken interconnected supporting rods or structure beneath the top layer of rods. Referring again to FIG. 3, the structure of the present invention improves the flow of water into the rain gutter over prior art, significantly, as has been observed in practice, in the field. This improvement is accomplished by allowing cylindrical rods 47 , with unbroken air space existing between them, to rest upon vertical leg supporting structures, which disallow any connecting path for forward water channeling due to water adhesion. Supporting structures 45 , 46 , 51 , & 54 are, indeed, each connected to the other by perforated planes 48 . However, this connection is broken by several factors, which disallow a forward flow of water. Water, instead, is forced downward into the rain gutter with no water adhesive path toward the front of the invention existing. This is accomplished by resting the rods 47 on slim vertical supports 45 , 46 , 51 ,& 54 . Doing so creates a “t” configuration unlike the simple rod structures of prior art. The present invention is an improvement in two instances: First, water that channels around simple rods, rather than “t” structures exhibits less siphoning action due to the water colliding on the underside of the rod after traveling down the opposing curved sides of the rod. This collision of water slows downward water flow by creating a back flow or upward flow of water against the rainwater attempting to channel downward along the curved surfaces of the rod. The “T” configuration of the present invention prevents such reverse flow or back flow of water against the incoming water flow by creating a continuing path of water flow away from water traveling down the opposite side of the “t”. This allows the filter skeleton 43 to create a stronger channeling or siphoning action on the incoming rainwater than prior art is able to exhibit. The “t” configuration also offers improvement over prior art because it creates an absolute break in the water adhesion flow on the bottoms of vertical legs 45 , 46 , 51 , & 54 . Water which will travel down rods 47 , then though the open air apertures 0 which exist in planes 48 , will next adhere to and travel down the lower (beneath planes 48 ) portions of the vertical legs of the “t”. Water traveling down the vertical legs, at this point, is an improvement over prior art such as U.S. Pat. No. 5,595,027 to Vail, U.S. Pat. No. 5,956,904 to Gentry, U.S. Pat. No. 5,619,825 to Leroney, U.S. Pat. No. 4,841,686 to Rees, U.S. Pat. No. 6,134,843 to Tregear, because it has discontinued it's forward flowing path on the underside of the perforated plane, as is common in the prior art, and is now being channeled, again, downward toward the inside of the rain gutter. Prior art, U.S. Pat. No. 4,745,710 also temporarily accomplishes this downward flow utilizing it's rod-supporting structure, but not nearly as effectively due to the interconnection of the underlying support structure, which provides a forward flowing water path by means of water adhesion along an unbroken surface. The improvement of the “t” configuration over prior art is again accomplished by a third, completely disconnected path of water flow, achieved at the lower termination of the vertical legs 45 , 46 , 51 , & 54 . Water, at these points, may only flow downward into the rain gutter. This is due to the length of the downward extensions of the vertical legs, which, by design, disallow backflow of water on the underside of the perforated planes 48 , or forward flow of water along a water adhesion path to the front lip of the rain-gutter. Filter Skeletal structure 43 of the present invention creates a siphoning action and ensures a downward, rather than forward flow of water not exhibited by prior art. Referring to FIG. 5 there is illustrated a cloth or wire filter membrane 50 , which employs intersecting threads. This membrane exhibits an improvement over other filtering and screening methods illustrated, representatively, in prior art U.S. Pat. No. 5,595,027 to Vail, U.S. Pat. No. 5,956,904 to Gentry, U.S. Pat. No. 5,619,825 to Leroney, U.S. Pat. No. 4,841,686 to Rees, U.S. Pat. No. 6,134,843 to Tregear, etching that it exhibits no tendency to trap and hold debris. The above mentioned prior art, even when employing micro-aperatured cloth, (due to adhesive actions of pollen, oil, pollutants, and silica dust which tend to heal over such products and remain impervious to cleaning by wind or water) has been observed, in the field, to clog due to tendencies to trap and hold debris, thereby channeling water past, rather than into the under lying rain gutter. Sub Heading 4b Filter Membrane Prior art, though naming filtering medium as cloth or screen or tangled mesh, has not recognized or utilized the improvements offered by a filtering membrane accomplished by the intersection of material of equal or larger and smaller wire, or cloth, or plastic thread configurations as is illustrated in FIG. 5 . Filtering and screening methods illustrated in prior art attempted to improve the propensity of reverse-curved or hooded gutter protection systems illustrated in prior art U.S. Pat. No. 5,557,891 to Albracht, and similar inventions, to trap and hold debris within their open channels. When this has occurred, water has flowed past the clogged open channels and to the ground due to waters tendency to bridge over debris trapped in a concave aperture. When debris rests on planar surfaces, water will travel beneath, rather than bridge over them, and attempt to travel through any open-air openings or apertures that exist beneath the debris. Filter and screening methods of gutter protection, however, illustrated in prior art have employed woven or knitted or mesh fibers or wires which intrinsically contain numerous joints, which tend to trap and hold debris. Filtering cloths, screens, and meshes are known to trap and hold debris to protect a medium on the other side of the filter. Screens, too, are known to trap and hold debris. When any of these methods of gutter protection have been employed in prior art, such inventions have been known to trap and hold debris reducing the amount of water that is able to enter an underlying rain gutter regardless of the porosity and/or density of the filter medium. The present invention exhibits no tendency to trap and hold debris, or dirt, or pollen and thereby offers a significant improvement over prior art. The present invention offers an improvement over prior art in that it's filtering membrane 50 , offers far fewer under and over knitted or woven or meshed joints for debris to become lodged within. The present invention also offers improvement over prior art in the existence of a strong water channeling action taking place beneath filtering membrane 50 throughout the structure of filter skeleton 43 . The water adhesive effects, strong siphoning action, and ultimate breaking of the water adhesion and resulting continued downward flow of water into an underlying rain gutter accomplished by the filter configuration illustrated in FIG. 6 offers improvements not found in prior art. Referring again to FIGS. 5 & 6, the present invention also exhibits an ability to clean or wash smaller particles out of the 100 micron openings existing between the interconnected threads or wires it employs. This ability has not been noted in prior art but, rather, prior art is known to clog with debris or cake over with pollen, leached shingle oil, dirt, and other pollutants and has not exhibited an ability to self-clean, found in the present invention. The present invention is an improvement over prior art that employs insertable, or under-affixed, or recessed filters such as is employed and illustrated in U.S. Pat. No. 5,595,027 to Vail, U.S. Pat. No. 5,956,904 to Gentry, U.S. Pat. No. 5,619,825 to Leroney, U.S. Pat. No. 4,841,686 to Rees, U.S. Pat. No. 6,134,843 to Tregear and similar prior art because these previous filtration attempts are known to either clog, heal over and become water-proof, and/or channel water forward. Recessed filters beneath a perforated plane such as employed in U.S. Pat. No. 5,595,027 to Vail receive far less water than the present invention due to water adhesion principals that direct water around, rather than through simple perforations. Filtration cloths or membranes resting on top of or sandwiched between screens, perforated planes, or denser filter mediums such as is illustrated in prior art U.S. Pat. No. 4,841,686 to Rees, U.S. Pat. No. 5,595,027 to Vail, U.S. Pat. No. 6,134,843 to Tregear and similar devices are also known to allow water channeling to the front lip of a rain gutter due to the unbroken inter-connected supporting or securing structures beneath or surrounding the filtering membrane and also due to the linear, rather than downward, channeling of water such filtering membranes themselves are known to exhibit in the field. REFERENCE NUMERALS IN DRAWINGS 0 perforations 1 extruded body 2 “scorable” top shelf 3 - 4 - 16 top, side, and bottom planes of 2 nd u-channel 5 vertical leg 13 - 16 v-shaped perforated well 6 vertical leg/“water dam” 12 - 7 - 8 bottom-side and top planes of 1 st u-channel 9 - 10 front “lip” of body 17 - 18 - 26 top, side, and bottom planes of 3 rd u-channel 20 reverse curved plane 22 open channel 19 - 20 rear supporting leg 21 pre-scored indentations 23 pre-scored indentation 24 open channel 25 open channel 28 rain gutter 29 rear u-shaped wall of gutter hangar 27 tensioning/securing flange 30 fastening screw 31 filter material 32 filtration membrane 35 “braked” or formed clip on cover 43 filtration skeletal structure 44 rear ledge of skeletal structure 45 “water drops” of equal length 46 termination of “water drops” 47 ellipses 48 width of perforated plane section 50 filter membrane 51 “water drop” of greater length 52 front ledge of skeletal structure 54 vertical leg 57 forward ledge of skeletal structure	An elongated strip of extruded plastics material includes a vertical rear plane adapted to seat on the rear portion of a gutter-hanging bracket. The rear vertical plane integrally connects to a second forward extending plane that joins, by means of an underlying u-shaped channel, a v-shaped perforated third plane that forces water to pool and drop through the perforations. The third plane joins, by means of an underlying u-shaped channel, a flange that projects outwardly for retaining the strip to a gutter. A filter configuration comprised of a debris repelling membrane, overlying a skeletal structure of ellipsoid rods spaced and resting on vertical planes, serves to break the forward flow of water and to channel water onto and through its integral perforated horizontal plane. The filter configuration is readily inserted into the u-shaped channels existing on the forward and rear edges of the v-shaped perforated third plane.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Application Ser. No. 61/079,636, filed Jul. 10, 2008, the full disclosure of which is hereby incorporated by reference herein. FIELD OF THE INVENTION This invention relates in general to production of oil and gas wells, and in particular to a wellhead assembly having a selectively removable wear bushing. DESCRIPTION OF RELATED ART Systems for producing oil and gas from subsea wellbores typically include a subsea wellhead assembly that includes a wellhead housing attached at a wellbore opening, where the wellbore extends through one or more hydrocarbon producing formations. Casing and tubing hangers are landed within the housing for supporting casing and production tubing inserted into the wellbore. The casing lines the wellbore, thereby isolating the wellbore from the surrounding formation. Tubing typically lies concentric within the casing and provides a conduit for producing the hydrocarbons entrained within the formation. Wellhead assemblies also typically include a production tree connecting to the upper end of the wellhead housing. The production tree controls and distributes the fluids produced from the wellbore. Valve assemblies are typically provided within wellhead production trees for controlling the flow of oil or gas from a wellhead and/or for controlling circulating fluid flow in and out of a wellhead. Gate valves and other sliding stem-type valves have a valve member or disc and operate by selectively moving the stem to insert/remove the valve member into/from the flow of fluid to stop/allow the flow when desired. In some techniques, the operator runs drill pipe through portions of a production tree and drills the well deeper before the well is completed. The production tree has internal sealing surfaces that could be damaged by the rotating drill pipe. To avoid damage, the operator will install a drilling protector, also called “wear bushing”, which is a sleeve that fits within the inner diameter of the production tree. After reaching total depth, the operator retrieves the wear bushing, typically by using the string of drill pipe. The operator may then run a string of tubing and land the tubing hanger in the production tree or a wellhead housing that supports the production tree. Retrievable wear bushings are also employed when drilling through other subsea wellhead members, such, as a wellhead housing. Normally, a riser will connect to the wellhead member, such as the tree or wellhead housing, and the operator runs and retrieves the drill pipe and wear bushing through the riser. SUMMARY OF INVENTION A method and system for retrieving a wear bushing from within a subsea wellhead assembly. The method includes providing a retrieval tool having a selectively extendable jack member and a selectively activatable bushing latch, with the bushing latch, coupling the retrieval tool with the bushing, and extending the jack member from the tool and pushing it against the wellhead assembly, so that the retrieval tool and the bushing are urged away from the wellhead assembly together. In one example, engaging the bushing latch is accomplished with the bushing. The bushing can include a recess on its inner surface and the bushing latch can be on a portion of the retrieval tool insertable into the bushing and configured to selectively extend radially outward from the retrieval tool and register with the recess, thereby coupling the retrieval tool and bushing. In one example, the jack member can be substantially parallel with the bushing axis so it contacts the wellhead assembly lateral to the bushing outer periphery. The jack member can be disposed on a portion of the retrieval tool having an outer periphery that is greater than the bushing outer periphery. After latching the retrieval tool to the bushing, the method can further include raising the retrieval tool and bushing from subsea. A remotely operated vehicle (ROV) can optionally be deployed subsea and operatively coupled to the retrieval tool and used to operate the retrieval tool. The bushing can be a wear bushing and the bore can be a main bore of the wellhead assembly. In one example of use, the bushing can be temporarily retained within the bore by a ring set in grooves respectively formed on the bushing outer surface and bore inner surface and wherein the grooves are at least partially registered with one another. Also disclosed herein is a method of completing a well subsea. In this example the method includes providing on the seafloor a wellhead member having a main bore and a wear bushing coupled within the main bore, landing a retrieval tool onto the wellhead member having a portion on the wellhead member and outside of the main bore periphery and latching the retrieval tool to the wear bushing, decoupling the wear bushing from the main bore by applying a separating force on both the wellhead member and retrieval tool, removing the wear bushing from within the main bore, landing tubulars within the main bore, and landing a production tree onto the wellhead member. A drill string can be inserted through the main bore and wear bushing and used for drilling a well into the seafloor. In one example, the retrieval tool can have an upper portion whose outer periphery contacts an upper surface of the wellhead member that circumscribes the main bore; the tool may include an attached lower portion insertable within the wear bushing. A groove may be included in the wear bushing that circumscribes its inner surface. A latch can be included on the tool lower portion that selectively projects radially outward; thus in one example the latching the retrieval tool to the wear bushing is accomplished by projecting the latch into registration with the groove. A jack member can be provided on the retrieval tool that is selectively extendable from its upper portion. Separating the bushing from the main bore may involve extending the jack member from the upper member to push it against the wellhead member apply the separating force. A remotely operated vehicle (ROV) can be coupled with the retrieval tool for operating the retrieval tool. Further described herein is a retrieval tool useful for retrieving a wear bushing from within a subsea wellhead member. The tool can include an upper portion for engagement by a lift line for landing on an upper end of the wellhead member, a lower portion depending from the upper portion and having an smaller outer periphery than the upper portion for insertion into the wellhead member, an elongated jack member selectively projectable from the upper portion and into an orientation substantially parallel with the lower portion axis, and a latch selectively extendable from the lower portion, so that when the retrieval tool is in a retrieval configuration with the lower portion inserted within the wear bushing, the latch engaged with the wear bushing, and the jack member is selectively projected from the upper portion, the jack member pushes against the wellhead member to move the retrieval tool away from the wellhead member and slide the wear bushing from within the wellhead member. The tool can include on it a remotely operated vehicle connection in communication with the latch and jack member. In one example of use, the latch is configured to engage a groove formed on the wear bushing inner surface. BRIEF DESCRIPTION OF THE DRAWINGS Some of the features and benefits of the present disclosure having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: FIG. 1 is schematic sectional view of a subsea wellhead assembly constructed in accordance with the present disclosure. FIG. 2 is a schematic sectional view of a tubing hanger being installed in the subsea wellhead housing of FIG. 1 . FIG. 3 is a schematic sectional view of a spool and tree cap being installed on the wellhead housing of FIG. 1 . FIG. 4 is a schematic sectional view of the tubing hanger being lowered through the previously installed spool. FIG. 5 is a schematic sectional view of a subsea well having a wear bushing. FIG. 6 is a view of the subsea well of FIG. 5 with a recovery tool engaging the wear bushing. FIGS. 6A and 6B provide in an enlarged view embodiments of the latch member of FIG. 6 . FIG. 7 illustrates a schematic view of the recovery tool of FIG. 6 pulling the wear bushing from the subsea well. FIG. 8 is a schematic sectional view of the recovery tool engaged with the wear bushing. While the subject device and method will be described in connection with the preferred embodiments but not limited thereto. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the present disclosure as defined by the appended claims. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows in a side sectional view a wellhead housing 13 with a conductor casing 15 depending to a predetermined depth within a subsea well 11 . A casing hanger 17 is landed within wellhead housing 13 with a string of casing 19 extending therefrom to another predetermined depth within subsea well 11 . Also landed within wellhead housing 13 is a tubing hanger 21 ; a tubing string 23 is shown within the casing string 19 and supported on its upper end by the tubing hanger 21 . In one example, the tubing string 23 extends to a production depth for receiving well fluid from within subsea well 11 . Tubing hanger 21 has an axially extending production flow passage 22 . A tubing annulus 25 is defined between the interior surface of string of casing 19 and the exterior surface of string of tubing 23 . Tubing hanger 21 optionally may have a tubing annulus passage 24 extending axially through it offset from and parallel to production flow passage 22 . In addition, a tubing annulus valve 26 may be located within tubing annulus passage 24 for opening and closing passage 24 . In one embodiment, tubing annulus valve 26 is biased by a spring to a closed position. Tubing hanger 21 is rotated or oriented to a desired orientation relative to wellhead housing 13 . Orientation may be accomplished in a variety of known ways. A production tree or spool 27 lands on and connects to an upper end portion of wellhead housing 13 . A schematically illustrated external connector 28 connects the spool 27 and wellhead housing 13 . Spool 27 and wellhead housing have a bore 29 extending axially therethrough that has a diameter at least equal to the outer diameter of tubing hanger 21 . This allows the tubing hanger 21 to be retrieved through spool 27 . Optionally, bore 29 may be as at least as large as the portion of the bore of wellhead housing 13 above casing hanger 17 to allow casing hanger 17 to be installed through spool 27 . An outlet port 31 is shown extending through a side wall of spool 27 The outlet port 31 can be used for the flow of production fluids from tubing 23 . At least one outlet valve 30 is mounted to the exterior of spool 27 to control the flow of well fluids exiting spool 27 through outlet port 31 . Well fluids flowing through outlet valve 30 may be delivered by methods known to those skilled in the art to a subsea collection manifold or to a platform located at the surface. A tree cap 33 is illustrated having a lower cylindrical portion that is closely received within bore 29 of spool 27 . Tree cap 33 may either connect to spool 27 internally or externally as shown. In this embodiment, tree cap 33 has an external flange 32 that lands on the rim or upper end of spool 27 . An external connector 34 connects tree cap 33 to a profile formed on the upper portion of spool 27 . Tree cap 33 has an axially extending production passage 36 . An isolation tube 35 is secured to the lower end of tree cap 33 . Isolation tube 35 extends downward and stabs into sealing engagement with production passage 22 in tubing hanger 21 . An outlet opening 37 extends laterally from production passage 36 through a sidewall of tree cap 33 to allow fluid flow to spool outlet port 31 . Upper and lower seals 38 A, 38 B extend around tree cap 33 and sealingly engage spool bore 29 above and below outlet port 31 . In this embodiment, upper seal 38 A is the uppermost pressure barrier that seals to bore 29 . A tubing annulus access port 39 extends through a sidewall of spool 27 below lower seal 38 B for registering with and monitoring annulus 25 . Tubing annulus access port 39 is in communication with spool bore 29 below lower seal 38 B. A valve 41 is mounted to the exterior of tubing annulus access port 39 for opening and closing port 39 . Tree cap 33 has a valve 43 above lateral flow outlet 37 for opening and closing access to its production passage 36 . If desired, a wire line plug profile could be formed in production passage 36 above flow outlet 37 for installing a wire line (or ROV tool installable) plug as a second pressure barrier within production passage 37 . Tree cap 33 optionally has a cylindrical mandrel portion above its flange 32 that has a grooved profile 45 for coupling to pressure control equipment, such as a riser or blowout preventer, during wire line or similar workover operations. Tree cap 33 may have an actuator 47 extending downward from its lower end for engaging and opening tubing annulus valve 26 . Actuator 47 could be a fixed probe that compresses the spring within tubing annulus valve 26 to cause it to open. Alternately, actuator 47 could be hydraulically extended and retracted. In this embodiment, tubing hanger 21 has a number of auxiliary passages 49 (only one shown) extending from its lower end to its upper end. Auxiliary passages 49 are used to control downhole safety valves (not shown), to communicate with downhole sensors, and for other functions, such as supplying power to a downhole electrical submersible pump. Auxiliary passage 49 is shown schematically connected to a downhole auxiliary line 50 that extends alongside tubing 23 for supplying hydraulic fluid pressure or electrical or optical signals. Each auxiliary passage 49 has a coupling receptacle on the upper end of tubing hanger 21 . In one embodiment, the tree cap 33 includes mating auxiliary passages 51 . A coupling 52 associated with each auxiliary passage 51 depends downward from tree cap 33 and stabs into sealing engagement with one of the auxiliary passages 49 in tubing hanger 21 . In this embodiment, the upper ends of at least some of the tree cap auxiliary passages 51 extend to a side of tree cap 33 above spool 27 . A controls module 53 having electrical and hydraulic control circuitry mounts to tree cap 33 for supplying hydraulic fluid pressure and electrical power to downhole safety valves and sensors. Controls module 53 may optionally be retrievable from tree cap 33 as well as retrievable along with tree cap 33 . Controls module 53 may also control tree cap valve 43 , if one is utilized. A separate controls module 55 may be mounted to a side of spool 27 for controlling valves 30 . If so, preferably controls module 55 is retrievable from spool 27 . In an example of operation, subsea wellhead housing 13 and conductor casing 15 are landed within subsea well 11 . As shown in FIG. 2 , a blowout preventer assembly (“BOP”) 57 is attached to an upper end portion of wellhead housing 13 . BOP 57 is a lower part of a string of drilling riser 59 that extends to a drilling vessel. Drilling operations are conventionally conducted through BOP 57 and wellhead housing 13 . When at total depth, casing hanger 17 and string of casing 19 are lowered through drilling riser 59 and BOP 57 , landed within wellhead housing 13 and cemented into place within the well in a manner known in the art. More than one string of casing may be installed. Tubing hanger 21 and a string of tubing 23 are then lowered on a running tool 61 and drill string through drilling riser 59 and BOP 57 . Tubing hanger 21 is oriented, landed, sealed, and latched conventionally in the bore of wellhead housing 13 . For example, the orientation may be with a pin and slot arrangement associated with BOP 57 , or a separate orientation spool might be employed. When tubing hanger 21 lands, tubing 23 will extend into the subsea well to a production depth. Normally, the operator will circulate the drilling mud from casing 19 by pumping down tubing annulus 25 and returning fluid up tubing 23 , or vice-versa. Running tool 61 can be used to open tubing annulus valve 26 and a downhole safety valve (not shown) to allow circulation to occur. The operator may also perforate and test the well in a conventional manner at this point. After perforating and testing the well, the operator lowers a temporary plug 63 ( FIG. 3 ) on a wire line through the drill string and running tool 61 and latches it within production passage 22 of tubing hanger 21 to seal subsea well 11 . The drilling riser and blowout preventer assembly 57 , 59 are then removed from connection with wellhead housing 13 . The drilling vessel may also leave the vicinity to drill another well. At this point, the operator can install additional equipment, such as piping on flow lines to a subsea manifold or the surface without BOP 57 and drilling riser 59 being in the way. At the surface, the operator assembles tree cap 33 to spool 27 with the desired orientation. The operator subsequently lowers the pre-unitized assembly of tree cap 33 and spool 27 , as illustrated in FIG. 3 , preferably on a lift line. It is not necessary for the vessel used to lower the assembly to have a derrick or the capability of running drill pipe. The operator orients and lands flow spool 27 complete and pre-unitized with tree cap 33 on an upper end portion of wellhead housing 13 . The orientation of spool 27 to wellhead housing 13 may be handled conventionally, such as with the assistance of an ROV (remote operated vehicle) and video cameras. Upon landing, isolation spool 35 stabs into engagement with production passage 22 of tubing hanger 21 , thereby defining an axial passage extending from a production depth of subsea well 11 to outlet opening 37 of tree cap 33 . Outlet opening 37 aligns with outlet port 31 so that well fluids can flow directly from outlet opening 37 through outlet port 31 . Also, upon landing of spool 27 , auxiliary couplings 52 connect auxiliary lines 50 to control module 53 via line 51 . In addition, tubing annulus valve actuator 47 stabs into tubing annulus valve 26 and opens it, which places annulus access port 39 in fluid communication with tubing annulus 25 . The operator plugs control modules 53 , 55 into a subsea umbilical that delivers electrical and hydraulic power and control signals. The operator can then remove plug 63 to initiate well fluid production from subsea well assembly 11 . This may be handled with a subsea plug removal tool (such as shown in U.S. Pat. No. 6,719,059) that is lowered on a lift line and attached to tree cap profile 45 with the assistance of an ROV. Upon removing plug 63 , the operator opens valve 30 to communicate well fluids from string of tubing 23 to a subsea manifold or to a collection facility located on a surface. For workover operations through tubing 23 , the operator may attach a riser to tree cap 33 and perform operations through tubing 23 , such as wire line operations. For a workover operation requiring the retrieval of tubing 23 , the operator can install wire line plug 63 back in tubing hanger 21 using a subsea plug retrieval tool, then retrieve tree cap 33 on a lift line. The operator would then attach a workover or drilling riser to spool 27 and pull tubing hanger 21 and tubing 23 in a conventional manner through the workover riser. Prior to pulling tubing hanger 21 , the operator would typically render the well safe by “killing” in a routine manner. Well circulation would be in the same manner as during completion, which is via running tool 61 , tubing annulus passage 24 in tubing hanger 21 and tubing 23 . If desired, the workover operation may include further drilling, such as drilling a sidetracked portion of the well to a more productive zone. In one method, the operator pulls tubing hanger 21 and production tubing 23 through spool 27 and the workover or drilling riser. The operator would then lower a drill string through the riser and spool 27 and drill a sidetracked portion of the well. The operator would run casing or a liner through the riser and spool 27 into the sidetracked portion and install a string of tubing in the sidetracked portion. The operator would complete the sidetracked portion of the well in the same manner as described above. FIG. 4 illustrates an alternative embodiment, which involves drilling the well through spool 27 . Wellhead housing 13 and conductor casing 15 are installed in a conventional manner as in the first method. After installing wellhead housing 13 and outer casing 15 , the operator then orients, lands and connects spool 27 to an upper end portion of wellhead housing 13 . Typically spool 27 is installed via a lift line, but it could also be run on a drill string. The operator then lowers the drilling riser 59 and connects BOP 57 with the profile on an upper end portion of spool 27 . The operator then continues drilling through BOP 57 and spool 27 . Such an operation is also known as “drill through” operations. Upon drilling subsea well 11 to a desired depth, operator then lowers casing hanger 17 with string of casing 19 attached thereto through drilling riser 59 and BOP 57 and lands, sets and seals casing hanger 17 within wellhead housing 13 . The operator then lowers tubing 23 to the production depth of subsea well 11 and lands tubing hanger 21 in wellhead housing 13 . The operator completes and tests the well in a conventional manner through the drilling riser and BOP 57 . Using a wire line, the operator then lowers plug 63 ( FIG. 2 ) through BOP 57 to sealingly close subsea well 11 . The operator then removes drilling riser 59 and BOP 57 . The operator then lowers tree cap 33 ( FIG. 1 ) via a lift line to land within spool 27 . As before, isolation tube 35 is attached to tree cap 33 and stabs into sealing engagement with production passage 22 in tubing hanger 21 . Tree cap auxiliary passages 51 mate with auxiliary passages 49 in tubing hanger 21 . Upon landing tree cap 33 within spool 27 , the operator can remove plug 63 from tubing hanger 21 to allow well fluids to flow from a lower end portion of string of tubing 23 to outlet opening 37 . The operator then opens valve 30 to allow flow of well fluids from subsea well 11 to a subsea manifold collection manifold or to the surface. Significant advantages are presented herein. In addition to serving as a pressure barrier, the tree cap 33 provides a communication flow path for the production fluid from the tubing hanger 21 to the production flow outlet in the spool. Completing the well before running the spool, as in another embodiment, allows the drilling rig to moved, if desired, before installing the spool. The spool and tree cap can be assembled as a unit and lowered on a lift line on a vessel that may lack a derrick. In the second embodiment, the well may be drilled to total depth and casing installed through the spool. In both embodiments, for workover operations requiring retrieval of tubing, the tree cap can be pulled without disturbing the spool. Auxiliary lines, such as for downhole sensors and safety valves, may be lead through the tree cap to the exterior of the tree cap above the spool. The control module associated with these functions may be mounted to the tree cap and retrievable along with the tree cap. The controls for the valves of the spool may be in a separate module, if desired, and attached to the spool. Landing the tree cap on the rim of the spool avoids the need for a landing shoulder within the bore of the spool. Alternate methods of subsea operations are illustrated in FIGS. 5 through 8 . A wellhead assembly 10 is shown in a side sectional view in FIG. 5 having spool 27 mounted on top of wellhead housing 13 . External connector 28 schematically couples the spool 27 and wellhead housing 13 . The wellhead assembly 10 of FIG. 5 includes a drilling protector or wear bushing 70 . The wear bushing 70 as shown is an annular member or sleeve coaxially inserted within the bore 29 . The wear bushing 70 includes a lower end 71 shown positioned adjacent a radially inwardly directed profile 14 circumscribing the well head housing 13 inner diameter. The profile 14 defines a bore 29 diameter transition and lies in a plane generally orthogonal to the bore 29 axis. The lower end 71 of wear bushing 70 is correspondingly shaped to match the profile 14 . As shown, the respective inner diameters of the wear bushing 70 and bore 29 below the profile 14 are substantially the same to minimize an edge from protruding radially inward along the profile 14 . Without an edge at the profile 14 , a seamless path is provided for tool insertion through the wellhead assembly 10 . Moreover, the wear bushing 70 protects the spool 27 and well head housing 13 inner diameter along the bore 29 from potential damage from tools, such as a drill bit and string 75 , inserted through the bore 29 . A split ring 18 is shown residing in corresponding channels 12 , 72 respectively formed along the inner and outer diameters of the well head housing 13 and wear bushing 70 . The split ring 18 axially secures the wear bushing 70 in the bore 29 . Optionally, coupling the wear bushing 70 within the bore 29 may be accomplished using an interference 20 comprising corresponding protrusions and indentations. As will be discussed in more detail below, a retrieval channel 73 for removing the wear bushing 70 is shown formed radially along the wear bushing 70 inner diameter near the upper end of wear bushing 70 . Other means for coupling the wear bushing 70 within the bore 29 and retrieving the bushing 70 are available and the scope of the present application is not limited to the embodiments illustrated in the figures. Included with the embodiment of FIG. 5 is a drilling riser 40 , where its lower end is attached to the spool 27 upper terminal end. Drilling riser 40 would normally include a blow out preventer (BOP). The wear bushing 70 may be preinstalled within the bore 29 on the spool 27 . If a drill system is used, the wear bushing 70 may be optionally recovered through the drilling riser 40 in a conventional manner, such as with a retrieval fitting attached to a drill string. The wear bushing 70 is recoverable with an ROV after riser 40 is disconnected; the recovery can take place in parallel with retrieving the BOP stack and riser 40 . FIGS. 6 through 8 depict a method of retrieval of wear bushing 70 from the subsea well 11 after riser 40 has been disconnected. Referring to FIG. 6 , a side schematic view is illustrated of a retrieval tool 42 engaging the wear bushing 70 . A lift line 48 shown attached to the retrieval tool 42 can be used for raising and lowering the tool 42 . The retrieval tool 42 includes an ROV panel or port 80 coupled to a schematically depicted ROV 78 through a line 79 . The ROV 78 can be used to assist with deploying the retrieval tool 42 . A cylindrical extension 54 downwardly depends from the retrieval tool 42 lower end where it is coaxially inserted within the wear bushing 70 annulus. A latch member 44 is included with the retrieval tool 42 that is selectively extendable radially outward from the extension 54 shown registering with the retrieval channel 73 . Latch member 44 extension may be initiated by a hydraulic pressure signal sent from the ROV 78 through the line 79 . FIG. 6A , which is an enlarged view of a portion of FIG. 6 , schematically depicts an embodiment of latch member 44 operation having a hydraulic circuit 82 communicating between the ROV panel 80 and the latch member 44 . Inserting the latch member 44 into the retrieval channel 73 , couples together the retrieval tool 42 and wear bushing 70 . Latch member 44 extension may be initiated by a hydraulic pressure signal sent from the ROV 78 through the line 79 . Optionally, as shown in FIG. 6B , the latch member 44 A may be a cam ring. An example of a cam ring is provided in Radi, et al., U.S. Pat. No. 6,070,669, issued Jun. 6, 2000 to the assignee of the present application, the contents of which is incorporated by reference herein. A tapered sleeve 84 is pushed downward in response to applied pressurized hydraulic fluid that in turn urges the latch member 44 A into the groove 73 for coupling the retrieval tool 42 and wear bushing 70 . As depicted in FIG. 7 , a push off jack 56 is urged downward from the tool 42 against the spool 27 upper surface, thereby separating the tool 42 and wear bushing 70 from within the spool 27 . Although a single push off jack 56 is shown, two or more push jacks 56 may be included. The force applied by the push off jack 56 against the spool 27 exceeds the retaining force provided from the split ring 18 in the channels 12 , 72 as well as that of the interference 20 . The push off jack 56 can be hydraulically activated via the ROV 78 and ROV panel 80 , such as by directing pressurized hydraulic fluid to the panel 80 from the ROV 78 through the line 79 . Optionally, the panel 80 may include a supply or source of pressurized fluid for extending the push off jack 56 , and the line 79 carries a signal from the ROV 78 to deploy the push off jack 56 . Alternatively, an expander (not shown) can be employed to expand the split ring 18 into the channel 12 formed in the well head housing 13 thereby removing it from the bushing channel 72 and releasing the wear bushing 70 from the wellhead assembly 10 . In another alternative, if the interference 20 couples the wear bushing 70 to the bore 29 , an overpull from the lift line 48 can unseat the wear bushing 70 from the interference 20 for retrieval. FIG. 8 is a side schematic sectional view of the wear bushing 70 attached to the retrieval tool 42 , where the retrieval tool 42 is suspended on the lift line 48 . In this embodiment, the retrieval tool 42 and wear bushing 70 can be in the process of being retrieved from a subsea well, or deployed to a subsea well. The ROV 78 is illustrated proximate the wellhead assembly 11 , but could instead be accompanying the retrieval tool 42 . In one embodiment, the wear bushing lower end 74 could be made from or coated with a material softer than the material of most or all components of the wellhead assembly 11 . Thus inadvertent impacts between the wear bushing 70 and wellhead assembly 11 would likely first deform the softer material, thereby preventing damage to the wellhead assembly 11 and its components. Wellhead components susceptible to damage include gaskets that may be struck by the bushing lower end 74 during retrieval. Examples of softer materials include elastomers, soft metals, and other pliable or otherwise malleable materials. It should be apparent to those skilled in the art that the present disclosure is not limited to the embodiments described, but is susceptible to various changes without departing from its scope.	A method and system for retrieving a wear bushing from within a subsea wellhead assembly. The system includes a retrieval tool deployable on a wireline that inserts within the bushing. Latches on the tool radially project outwards and mate with a groove on the bushing inner surface. A hydraulically actuated jack is included with the tool and projects downward to the wellhead assembly to pull the bushing from its temporary coupling in the wellhead assembly. A remotely operated vehicle can be used to assist deploying the tool and for supplying hydraulics and/or control for operating the latch and the jack.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION [0001] The present invention relates to improvements in or relating to downhole tools, and is more particularly, although not exclusively, concerned with reamer tools. BACKGROUND TO THE INVENTION [0002] Earth formation drilling utilises a long string of drilling pipes and tools coupled together. All elements of the drilling string are rotated together in order to rotate a cutting bit at the end of the drilling sting. The cutting bit creates a hole in a formation through which the rest of the drilling string moves in a drilling direction. An under-reamer, coupled between two other elements of the drilling string, is used to widen the walls of the hole created by the drill bit. The under-reamer, also known as a reamer, normally has an overall diameter in its retracted position which is the same as or less than the diameter of the hole being drilled. When in its deployed position, cutting elements are moved away from the body of the under-reamer to define a diameter which is larger than the diameter of the hole being drilled. As the under-reamer moves downhole rotating with the drilling string, it widens the hole in the formation behind the drill bit. In addition, an under-reamer may be used to open a collapsed formation on its way back up to the surface. [0003] WO-A-2005/124094 describes one such under-reamer or reamer tool. The reamer tool comprises a tubular body having an axial cavity and housings arranged around its periphery to define external openings. In each of these openings, a cutter element is housed which comprises two cutter arms that can be moved between a retracted position where each cutter element is fully retained within its associated housing, and an expanded position where each cutting element extends outside its opening so that more material can be cut away the walls of the hole in a formation thereby enlarging its diameter. A drive mechanism is provided within the tubular body to move the cutter elements between their retracted and expanded positions. [0004] In the reamer tool described in WO-A-2005/124094, one cutter arm is pivotally connected to the tubular body at one end and to the other cutter arm at the other end, the other cutter arm being connected to the drive mechanism so that both cutter arms can be retracted and expanded. The arrangement formed by the two cutter arms when deployed is a ‘V’-shape where the vertex of the V is outside the opening. [0005] Typically, such reamer tools are operated by the pressure of fluid passing through the drill string, and in particular, through the tool section itself. The pressure of fluid is controlled by the operation of a pump associated with the drill string. In US-A-2010/0006339, the pressure of fluid passing through the tool is used to operate the reamer so that it is expanded or retracted in accordance therewith. Here, the reamer assembly comprises cutter elements and stabiliser pads mounted for sliding movement on grooves. In the retracted position, the reamer assembly is housed within a recess, the reamer assembly being moved to the expanded position by movement along the grooves so that it is outside the recess. Fluid pressure is sensed to activate the expansion and retraction of the reamer. [0006] US-A-2010/0096191 discloses an under-reaming and stabilisation tool in which a blade element is moved from a retracted position to an expanded position by wedge elements coupled to a drive tube, the wedge elements interact with an inclined face of the blade element to effect the raising (expansion) and lowering (retraction) of the blade element relative to a guide channel. As the drive tube moves along the length of the tool body, the wedge elements are drawn along therewith and they slide under the inclined face of the blade element causing radial movement of the blade element to raise out (expand) out of its guide channel. Movement of the drive tube in the opposite direction along the length of the tool body withdraws the wedge elements from under the inclined face of the blade element allowing radial movement of the blade element to lower (retract) into its guide channel. The expansion of the blade element is limited by the actuation mechanism, that is, the drive tube and wedge elements coupled thereto. SUMMARY OF THE INVENTION [0007] It is therefore an object of the present invention to provide an improved reamer tool in which the cutter arms or blades are maintained parallel to the axis of the reamer tool in both its retracted and deployed positions as well as during expansion and retraction whilst providing a higher opening range. [0008] It is a further object of the present invention to provide a reamer tool in which the opening can be adjusted at the surface in accordance with a value within the opening range whilst providing a more efficient reamer tool. [0009] In accordance with a first aspect of the present invention, there is provided a reamer tool comprising: [0010] a substantially hollow body having a longitudinal axis and including an external wall having a first outer diameter; [0011] at least one arm bay formed in a portion of the external wall around the periphery of the body; [0012] at least one expandable arm located in an associated arm bay and mounted for expansion between a retracted position within the body and an expanded position in which each expandable arm describes a second outer diameter which is greater than the first outer diameter; and [0013] at least one expansion mechanism for expanding an associated expandable arm between the retracted and expanded positions; [0014] characterised in that each expansion mechanism comprises two elongate links pivotally connected to the associated expandable arm at one end position and to its associated arm bay at another end position, each expandable arm being pivotally mounted at the two end positions with respect to its associated arm bay so that each expandable arm is maintained substantially parallel to the longitudinal axis of the body in both the retracted and expanded positions and during its expansion and retraction between the retracted and expanded positions. [0015] By having links connecting each expandable arm to its associated arm bay, the expandable arm can be maintained substantially parallel to the longitudinal axis of the reamer tool thereby providing an opening range which is greater than that possible with expansion mechanisms comprising wedge elements or the like. [0016] In the case where the downhole tool comprises a reamer tool, the advantage of maintaining the expandable arm parallel to the longitudinal axis of the body is that the attack point for each cutting blade is reliable, the attack point being the point at which a leading cutting element engages with the material or formation to be cut. [0017] Naturally, an actuation mechanism is also provided for activating the expansion mechanism, each expandable arm being pivotally connected at another end position to the actuation mechanism. [0018] Advantageously, the expansion mechanism further comprises a third elongate link pivotally connected to each expandable arm and to the actuation mechanism. [0019] In this way, the actuation mechanism directly moves the expandable arm and the other elongate links serve to maintain the substantial parallelism with the longitudinal axis. In a preferred embodiment, the actuation mechanism comprises a piston. [0020] The downhole tool may further comprise at least one return member for deactivating each deployment mechanism. In one embodiment, each return member comprises a spring biased against the action of the actuation mechanism. [0021] A shoulder block may be provided which is locatable in each arm bay to limit the expansion of the expandable arm. By selecting a suitably sized shoulder block, the expansion of the expandable arm can be determined to provide a desired outer diameter for engagement with a formation. [0022] In a preferred embodiment, the second outer diameter may be up to 1.3 times the first outer diameter. For example, if the outer diameter of the downhole tool is 100 cm, the expandable arms may be expanded to describe an outer diameter of up to 130 cm. [0023] Preferably, the downhole tool comprises a reamer tool and each expandable arm comprises a cutter arm. [0024] In accordance with another aspect of the present invention, there is provided an expandable cutter arm for a downhole tool, the expandable cutter arm comprising at least a front cutting blade and a back cutting blade, each cutting blade comprising a plurality of cutting elements, one cutting element on each of the front cutting blade and the back cutting blade providing an attack point for the associated cutting blade. [0025] Such an expandable cutter arm may further comprise a first side and a second side located either side of a plane, each side being spaced at respective predetermined distances from a plane so that the attack point for the front blade and the attack point for the back blade are equi-spaced from the plane. [0026] By having the attack point for each cutter arm equi-spaced from the plane, efficiency of the reamer tool is improved. In addition, a more flexible reamer tool is provided in which a range of opening sizes can be accommodated. [0027] The predetermined distance for the first side may be different to the predetermined distance for the second side. [0028] In one embodiment, the cutting elements may comprise polycrystalline diamond cutting elements. [0029] In accordance with a further aspect of the present invention, there is provided a reamer tool having at least one expandable cutter arm as described above. [0030] In accordance with another aspect of the present invention, there is provided a reamer tool having a longitudinal axis, the reamer tool comprising at least one expandable cutter arm having a plurality of cutting elements arranged to form at least a front cutting blade and a back cutting blade, one of the cutting elements on the front cutting blade and one of the cutting elements on the back cutting blade providing respective attack points for their associated cutting blades, characterised in that the attack point for the front cutting blade and the attack point for the back cutting blade are equi-spaced from a plane extending through the longitudinal axis. [0031] The reamer tool preferably further comprises at least one expansion mechanism for expanding an associated expandable cutter arm between a retracted position and an expanded position, and an actuation mechanism for activating each expansion mechanism. [0032] In a preferred embodiment, each expansion mechanism comprises at least two elongate links pivotally connected to the associated expandable cutter arm at one end position and to its associated arm bay at another end position, each expandable cutter arm being pivotally mounted at the two end positions with respect to its associated arm bas so that each expandable cutter arm is maintained substantially parallel to the longitudinal axis in both the retracted and expanded positions, and, during expansion and retraction between the retracted and expanded positions. [0033] The expansion mechanism advantageously further comprises a third elongate link pivotally connected to each expandable cutter arm and to the actuation mechanism, each expandable cutter arm being pivotally connected at another end position to the actuation mechanism. [0034] The actuation mechanism preferably comprises a piston. The reamer tool may further comprise at least one return member for deactivating each expansion mechanism. [0035] A shoulder block may be provided which is locatable in each arm bay to limit the expansion of the expandable cutter arm. The cutter arm may have an opening range up to 1.3 times the outer diameter of the reamer tool, the shoulder block limiting the opening in accordance with it size. [0036] In accordance with another aspect of the present invention, there is provided a control module for a downhole tool, the downhole tool including a substantially hollow body having a longitudinal axis, at least one arm bay formed around the periphery of the substantially hollow body, at least one expandable arm located in an associated arm bay and mounted for expansion between a retracted position within the substantially hollow body and an expanded position in which the expandable arm describes a second outer diameter which is greater than the first outer diameter, at least one expansion mechanism for expanding an associated expandable arm between the retracted and expanded positions, and a piston for operating each expandable arm, the control module comprising: [0037] an element mounted within the body which is moveable between a first position and second position; [0038] a motor controlling the movement of the element; and [0039] a gearing mechanism associated with the motor for transferring drive from the motor to the element; [0040] characterised in that the control module further comprises a chamber and a port, the chamber being associated with the piston and the port having an open position and a closed position, the open and closed position being determined by the second and first positions respectively of the element; [0041] and in that the port, in its open position, allows fluid to flow into the chamber and to increase the pressure therein for operation of the piston to expand each expandable arm. [0042] In a preferred embodiment, the motor and gearing mechanism are mounted between the element and the external wall of the body. A power source is preferably located within the body of the reamer tool. This has the advantage of protecting the control module, that is, the motor, gearing mechanism and power source from the environment in which the reamer tool operates. [0043] In one embodiment, the power source comprises a battery. In another embodiment, the power source comprises a turbine arranged to generate power for the motor. [0044] The control module may further comprise at least one positional sensor for sensing the position of the element within the body. In addition, at least one pressure sensor may also be provided for sensing the pressure within the chamber. [0045] In addition, at least one sensor may be provided for sensing at least a change in pressure in fluid flowing through the downhole tool, each sensor providing a control signal for the motor. Moreover, at least one sensor may be provided for sensing a change in rotational speed of the downhole tool, each sensor providing a control signal for the motor. [0046] Additionally, a communications system may be provided through which control signals are provided for the motor. In one embodiment, the communications system includes a wired link over which control signals are transmitted. BRIEF DESCRIPTION OF THE DRAWINGS [0047] For a better understanding of the present invention, reference will now be made, by way of example only, to the accompanying drawings in which: [0048] FIG. 1 illustrates a schematic sectioned view of a reamer tool in accordance with the present invention, the reamer tool being shown in a retracted position; [0049] FIG. 2 is similar to FIG. 1 but illustrates the reamer tool in an expanded position; [0050] FIG. 3 illustrates cutters mounted on an arm of the reamer tool shown in FIGS. 1 and 2 ; [0051] FIG. 4 illustrates a sectioned view of a control system for the reamer tool shown FIGS. 1 and 2 with the reamer tool in the stowed position; [0052] FIG. 5 is similar to FIG. 4 but illustrates the control system with the reamer tool in the expanded position. DESCRIPTION OF THE INVENTION [0053] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. [0054] It will be understood that the terms “vertical” and “horizontal” are used herein refer to particular orientations of the Figures and these terms are not limitations to the specific embodiments described herein. In addition, the terms “top” and “bottom” are used to refer to parts of a drill string that face towards the surface, or top of the drill string, and away from the surface, or bottom of the drill string, respectively. [0055] The present invention relates to an improved reamer tool and a control system for operating such a reamer tool or other downhole tool. The reamer tool is described below with reference to FIGS. 1 to 3 and the control system is described with reference to FIGS. 4 and 5 . [0056] Although the present invention is described below with respect to a reamer tool having cutter arms, it is equally applicable to a downhole tool that may also be used for stabilisation. In this case, the cutter arms are replaced by stabilising pad arms which, when expanded, contact the walls of a formation to stabilise the drill string of which the tool forms a part. In addition, although the control system is described with reference to use with a reamer tool, it is not limited to use with a reamer tool and can be used with any other downhole tool. [0057] Reamer tools, as well as other downhole tools, are operated, that is, expanded and retracted by changes in the pressure of fluid flowing through the associated drill string. The fluid flow is controlled by a pump associated with the drill string. Changes in fluid pressure are detected by sensors located at appropriate positions in the drill string. [0058] Referring initially to FIGS. 1 and 2 , a longitudinal sectioned view of reamer tool 100 is shown. The reamer tool 100 comprises a reamer body 105 having three cutter arms 110 mounted within respective housings or arm bays 115 formed in the reamer body 105 . The three cutter arms 110 are equi-spaced around the periphery of the reamer body 105 but only one such cutter arm is shown in FIGS. 1 and 2 . [0059] Each cutter arm 110 comprises a cutting element or cutting blade 120 which is pivotally mounted on each of three elongate links 125 , 130 , 135 at respective pivot points 140 , 145 , 150 as shown. Two of the elongate links 125 , 130 are also pivotally attached to the housing or arm bay 115 at respective pivot points 155 , 160 . The third elongate link 135 is also pivotally mounted, by means of a pivot point 165 , on a piston 170 . [0060] The piston 170 comprises an actuation mechanism and is operated to move from a first position as shown in FIG. 1 to a second position as shown in FIG. 2 to expand the cutter arms 110 , and more particularly, the cutting elements or cutting blades 120 , from a retracted position to an expanded position where the cutting elements or cutting blades 120 extend outside the reamer body 105 and define an outer diameter which is up to 1.3 times that of the normal outer diameter of the reamer body 105 . [0061] It will be appreciated that, in other embodiments of the reamer tool 100 in accordance with the present invention, the outer diameter defined by the three cutter arms 110 and their cutting elements or cutting blades 120 may have other ratios compared to the outer diameter of the reamer body 105 as required, and, is therefore not limited to up to 1.3 times the outer diameter of the reamer body 105 . The outer diameter is limited by a shoulder block 175 and the size of the shoulder block 175 is chosen at the surface before introduction of the drill string of which the reamer tool 100 forms a part into a wellbore in a formation in accordance with the outer diameter of the reamer tool 100 required to from the wellbore in the formation. [0062] It will be appreciated that shoulder blocks of different sizes can be provided with the reamer tool 100 and an appropriately sized shoulder block is chosen to limit the expansion of the cutter arms 110 to control the outer diameter defined by the expanded cutter arms 110 and cutting elements or cutting blades 120 within an opening range from the same outer diameter of the reamer body 105 to 1.3 times that outer diameter. [0063] In the deployment of the cutter arms 110 from inside their respective housings or arm bays 115 formed in the reamer body 105 , the cutting structure (not shown) of each cutter arm 110 always remains parallel to a longitudinal axis 180 of the reamer body 105 . The pivot points 140 , 145 , 150 , 155 , 160 , 165 formed on respective ones of the links 125 , 130 , 135 , as described above, effectively provide pivoting axes about which rotation can occur to expand and retract the cutter arms 110 and cutting elements or cutting blades 120 out of and into their respective housings or arm bays 115 . However, pivot points 140 , 145 provided on respective links 125 , 130 ensure that the cutter arms 110 remain parallel to the reamer body 105 as they are expanded, used for cutting and retracted into their respective housings or arm bays 115 . Pivot point 150 provided on elongate link 135 is used to expand and retract the associated cutter arm 110 in accordance with the movement of the piston 170 or other actuation mechanism as will be described in more detail below. [0064] By using an expansion mechanism which utilises elongate links pivotally connected to both the cutter arm 110 and the housing or arm bay 115 as well as to the piston 170 or other actuation mechanism, the effective outer diameter of the cutter arm 110 and cutting element or cutting blade 120 can extend up to 1.3 times the outer diameter of the reamer body 105 . In addition, the amount of expansion can easily be limited by a suitable shoulder block 175 . [0065] The force for expanding the cutter arms 110 is provided by pressure applied to the piston 170 , and, the force for retracting the cutter arms is provided by a spring 185 (described below with reference to FIGS. 4 and 5 ). The applied pressure is provided by fluid flow through the reamer body 105 as will be described in more detail below. [0066] As shown in FIGS. 1 and 2 , the reamer body 105 is substantially tubular with a hollow central portion 190 which defines a fluid flow path. The piston 170 is mounted within the reamer body 105 and is operated by fluid flowing therethrough as will described in more detail with reference to FIGS. 4 and 5 below. [0067] In the embodiment of the reamer tool 100 described above, it is essential to ensure that the cutting elements, for example, polycrystalline diamond cutters known as PDC cutters, function adequately during the expansion stages to make contact with the formation in which the reamer tool is to be used. This is described in more detail with respect to FIG. 3 . [0068] In FIG. 3 , a portion 200 of a cutter arm 110 of the reamer tool 100 shown in FIGS. 1 and 2 is shown in more detail. The positioning of the cutting elements with respect to the cutter arm 110 is shown. The portion 200 shows a single cutter arm 110 ( FIG. 1 ) having two cutting blades 205 , 210 , a front cutting blade 205 and a back cutting blade 210 . [The terms “front” and “back” refer to the order in which the cutting blades make contact with the walls of a wellbore formed in a formation and is determined by the direction of rotation of the drill string (not shown) of which the reamer tool 100 ( FIG. 1 ) forms a part.] [0069] In the embodiment shown in FIG. 3 , five cutting elements 215 , 220 , 225 , 230 , 235 are visible on front cutting blade 205 , and six cutting elements 240 , 245 , 250 , 255 , 260 , 265 are visible on back cutting blade 210 . Cutting element 215 on front cutting blade 205 and cutting element 240 on back cutting blade 210 have respective attack points 270 , 275 which are equi-spaced from a plane 280 that is coincident with the longitudinal axis 180 of the reamer body 105 ( FIG. 1 ). This means that the distance from side 285 of front cutting blade 205 to the plane 280 is shorter than the distance from side 290 of back cutting blade 210 to plane 280 . [0070] In the embodiment shown in FIG. 3 , the cutting elements 215 , 220 , 225 , 230 , 235 , 240 , 245 , 250 , 255 , 260 , 265 comprise PDC elements as shown. Although eleven PDC elements are visible, the number of PDC elements present on each blade 205 , 210 is determined in accordance with the dimensions of the PDC element and the dimension of the reamer tool itself. However, it will be appreciated that other types of cutting elements may also be used, for example, impregnated cutting elements. [0071] By having the attack points 270 , 275 equi-spaced from the plane 280 , attack points 270 , 275 will contact the formation for any opening size in the opening range. If the attack points 270 , 275 are not equi-distant from the plane 280 , the cutter arms will only have one possible opening size to ensure that both the front and back cutting blades make contact with the formation. [0072] The front and back blades 205 , 210 as described above have different numbers of cutting elements 215 , 220 , 225 , 230 , 235 , 240 , 245 , 250 , 255 , 260 , 265 which are not aligned with one another so that the attack points 270 , 275 of cutting elements 215 , 240 are at different heights with respect to the reamer body 105 . [0073] The effective outer diameter of the reamer tool 100 , that is, the opening size is determined by the positions of attack points 270 , 275 . [0074] Referring now to FIGS. 4 and 5 , a schematic longitudinal sectioned view of the reamer tool 100 is shown. Components that have previously been described with reference to FIGS. 1 and 2 have the same reference numerals. [0075] The reamer tool 100 comprises the reamer body 105 having cutter arms 110 mounted within respective housings or arm bays 115 formed in the reamer body 105 as described above. The links and the pivot points that operate the cutter arms 110 as described above are not shown for clarity. The spring 185 that is used to return the expanded cutter arms to their retracted position is shown schematically as a block. [0076] As described above, the force for expanding the cutter arms 110 is provided by pressure applied to the piston 170 due to fluid flow through the reamer tool 100 , and, the force for retracting the cutter arms is provided by the spring 185 . During expansion of the cutter arms, the pressure exerted on the piston 170 creates a force which is greater than the force provided by the spring 185 . Once the pressure exerted on the piston 170 falls sufficiently so that the force exerted becomes less than the force provided by the spring 185 , the spring 185 causes the cutter arms 110 to be retracted into their respective housings or arm bays 115 . This is described in more detail below. [0077] A control system 300 for deploying the cutter arms 110 is provided within the reamer body 105 and comprises an electric motor 310 , a gearing system 315 and a moveable sleeve 320 , the electric motor 310 and gearing system 315 being housed between the sleeve 320 and an external wall 325 of the reamer body 105 . The electric motor 310 rotates at a first predetermined speed and the gearing system 315 reduces that first predetermined speed to a second lower predetermined speed which is used for operating the moveable sleeve 320 . In one embodiment, a ball screw (not shown) may be used to transfer the rotational output from the gearing system 315 to a linear movement which is used to move the sleeve 320 to open and close port 385 as will be described in more detail below. However, it will be appreciated that other arrangements may be used for transferring rotary motion from the gearing system 315 to linear motion of the moveable sleeve 320 , for example, a pinion or worm gear forming part of the gearing system 315 may engage with a rack element provided on the moveable sleeve 320 . [0078] The electric motor 310 may be powered by a battery (not shown) or from a turbine provided in the drill string (also not shown), the turbine generating a current from the fluid flow therethrough. Although a gearing system 315 is described, it will be appreciated that drive from the motor may be converted into linear movement by any suitable means for converting the output of the motor into linear movement. [0079] The housing or arm bay 115 for each cutter arm 110 is defined by a wall 330 of the hollow central portion 190 and a portion 335 of the external wall 325 of the reamer body 105 . The piston 170 is defined by a chamber 340 adjacent the cutter arm 110 , the chamber 340 being defined by the wall 330 of the central portion 190 , external wall 325 of the reamer body 105 , sleeve 320 , first cylindrical portion 345 , second cylindrical portion 350 and end wall 355 as shown. End wall 355 also forms barrier between the electric motor 310 and gearing system 315 of the control system 300 . [0080] Annular seals 360 , 365 are provided between the first cylindrical portion 345 and respective ones of wall 330 and sleeve 320 . Additional annular seals 370 , 375 are provided between sleeve 320 and second cylindrical portion 350 and with wall 380 of hollow central portion 190 . Seal 360 can be mounted on either the first cylindrical portion 345 or the wall 330 as the first cylindrical portion 345 does not move relative to the wall 330 . [0081] The first and second cylindrical portions 345 , 350 define the port 385 which is sealed by the moveable sleeve 320 when in a first position, as shown in FIG. 4 , so that fluid flows through the hollow central portion 190 as indicated by arrow 390 . When the sleeve 320 is in a second position, as shown in FIG. 5 , the port 385 is open and fluid can flow into chamber 340 as shown by arrow 395 . [0082] An additional seal 400 is also provided between the piston 170 and the external wall 325 of the reamer body 105 as shown to prevent ingress of drilling fluid as the piston 170 moves from the position shown in FIG. 4 to the position shown in FIG. 5 . [0083] Operation of the electric motor 310 effectively moves the sleeve 320 in the same direction as arrow 390 to open the port 385 and in the opposite direction to close the port 385 , drive from the electric motor 310 being transmitted to the sleeve 320 via the gearing system 315 . A control signal for the electric motor 310 is provided by way of an increased fluid flow rate through the hollow central portion 190 and/or speed of rotation of the drill string (not shown). At least one suitable sensor (not shown) is provided to sense the change in pressure and/or rotational speed and to provide a control signal for the electric motor 310 , for example, a pressure sensor for sensing changes in pressure and an accelerometer for sensing the change in rotational speed. However, other sensors may also be used for sensing the change in rotational speed. [0084] It will be appreciated that the electric motor 310 may be a bi-directional motor that operates in two directions to effect opening and closing of the port 385 . As an alternative to the electric motor 310 , a solenoid may be used to effect opening and closing of the port 385 . [0085] Naturally, the electric motor 310 and gearing system 315 are sealed within a region 410 defined by the sleeve 320 and an external wall 325 so that it is protected from the drilling environment, that is, the mud, rock etc., that finds its way into the hollow central region 190 . In a preferred embodiment, the region 410 is filled with oil to prevent the ingress debris from the drilling environment. [0086] Before the cutter arms 110 are expanded, they are housed in their respective housings or arm bays 115 as described above. Fluid flow is through the hollow central portion 190 as indicated by arrow 390 ( FIG. 4 ). When a control signal is sent to the electric motor 310 , by way of a change in pressure of the fluid flowing through the hollow central portion 190 and/or a change in the rotational speed of the drill string as described above, the electric motor 310 operates the moveable sleeve 320 to move it in the same direction as the fluid flow as indicated by arrow 390 to open port 385 ( FIG. 5 ). [0087] When the port 385 is opened, fluid flows into the chamber 340 and pressure builds up therein. When the pressure in the chamber 340 reaches a value where the force exerted by the piston 170 is greater than the force exerted by the spring 185 , the piston 170 is pushed from the position shown in FIG. 4 towards the arm bays 115 to expand the cutter arms 110 as shown in FIG. 5 . Movement of the piston 170 towards the arm bays 115 causes each cutter arm 110 to pivot about pivot point 150 on link 135 , as well as pivot points 140 , 145 on links 125 , 130 , so that it is expanded from the within its associated arm bay 115 as shown in FIGS. 1 and 4 , to the position as shown in FIGS. 2 and 5 . Fluid built up in the chamber 340 flows out of nozzles 415 associated with the cutter arms 110 maintaining the position of the piston 170 as shown in FIGS. 2 and 5 , and hence the expansion of the cutter arms 110 , until the port 385 is closed by the sleeve 320 by the operation of the motor 310 and gearing mechanism 315 . [0088] On receipt of a further control signal, that is, another change in pressure of the fluid flow and/or a change in rotational speed of the drill string, the motor 310 is activated once again to move the moveable sleeve 320 from the position shown in FIG. 5 back to the position shown in FIG. 4 , thereby closing the port 385 so that no more fluid flows into the chamber 340 as indicated by arrow 395 . Fluid flows out of nozzles 415 until the pressure in the chamber 340 is reduced so that the force of the spring 185 causes the cutter arms 110 to be returned to their associated housing or arm bay 115 to be returned to the position shown in FIGS. 1 and 4 . In addition, the piston 170 is pushed back but the force exerted by the spring 185 to its initial position as shown in FIGS. 1 and 4 . [0089] Alternatively, instead of operating the motor 310 , the cutter arms 110 may be retracted by turning the pump off that is associated with the drill string so that fluid flow is switched off through the drill string, and the pressure in the chamber 340 falls as no further fluid flows through the port 385 and into the chamber 340 . Once the pressure in the chamber 340 falls to a value where the force exerted by the spring 185 exceeds that of provided by the pressure in the chamber 340 , the piston 170 is moved back to the position shown in FIGS. 1 and 4 and the cutting arms 110 retracted whilst still parallel to the longitudinal axis 180 due to their pivoting about points 140 , 145 , 150 ; pivoting of the links 125 , 130 about points 155 , 160 in the respective housing or arm bay 115 ; and pivoting about pivot point 165 due to movement of the piston 170 as it moves from the position shown in FIG. 5 back to the position shown in FIG. 4 . [0090] As mentioned above, the control system 300 includes a power supply (not shown), but it may also include other electronic equipment, for example, pressure sensors for sensing the pressure in the chamber 340 , accelerometers for measuring the speed of movement of the sleeve 320 and piston 170 and the rotational speed of the drill string, as well as the speed of the cutter arm 110 during its expansion and retraction phases. In addition, a communication device (not shown) may be provided through which control signals can be provided for the electric motor in the case where the control signals are not supplied by changes in pressure of the fluid flow or rotational speed of the drill string as described above. [0091] The power supply may be provided by one or more batteries or via a wired link from the surface. Additionally, the wired link may form part of the communication device through which the control signals may be transmitted to the electric motor. [0092] It will be appreciated that the cutter arm expansion mechanism can be used with other tools, for example, downhole stabilisers, and the cutter arms can be expanded using other expansion mechanisms. [0093] Although a specific embodiment of the present invention is described, it will be appreciated that this embodiment is not limiting and other embodiments may fall within the scope of the invention as defined by the appended claims.	Described herein is a reamer tool ( 100 ) having a body ( 105 ) with bays ( 115 ) in which cutter arms ( 110 ) are mounted for deployment between a stowed position and a deployed position. A deployment mechanism is provided for deploying the cutter arms from their stowed position to their deployed position that maintains each cutter arm in a position that is substantially parallel to a longitudinal axis of the body ( 105 ) whilst in its stowed position and in its deployed position as well as during its deployment from its stowed position to its deployed position. A control module ( 300 ) is also described for controlling the deployment of the cutter arms ( 110 ). The control module ( 300 ) comprises a motor ( 310 ), a gearing mechanism ( 315 ) and a moveable element ( 320 ) that closes a port ( 385 ) in a first position and opens the port ( 385 ) in a second position. Fluid flow enters a chamber ( 340 ) behind a piston ( 170 ) through the port ( 385 ) to allow pressure to build up before actuating the piston ( 170 ) and thereby the deployment mechanism for the cutter arms ( 170 ).
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION The present invention concerns a rigid track bed of concrete, especially made of precast concrete modules, with a slab and continuous fastenings or a multiplicity of fastenings for rails mounted thereon for track guided vehicles. DE 198 50 617 A1 discloses cross ties for a rigid run of track. Individual ties are aligned in rows, thus forming a base substrate for rails which are subsequently laid thereon. The individual ties are separated from each other at a predetermined distance and are predominately not rigidly tied together. In order to enable the best possible disturbance-free travel of a rolling wheel of a track guided vehicle, the proposal is to place bearing elements upon the rails, which can be integrated into tie and concrete structure below. The concrete understructure is further molded with retaining grooves, wherein a derailed wheel can run. The concrete ties possess, in turn, a specified spacing from one another, so that a rail-borne wheel rolls from one tie to another. The ties and the track fastenings, as well as the bearing elements, are all subject to damage thereby. DE 199 31 048 A1 teaches the placement of a rail for track guided vehicles on a rail bearing slab. On the slab are provided absorbent pads, which are affixed to the rail bearing slab by bolts. If derailment protection is required, then the absorption pads serve immediately to the affixing of the surface protection elements, on which the derailed wheel can roll. The absorbent pads serve, in such a case, as a noise control and as a fastening element for derailment safety equipment. The positional arrangement of the derailment protection rails along the track has been made known by DE 44 38 397 A1, or by DE 199 41 060 A1. In a similar manner to DE 199 31 048 A1, a derailment protection rail made of iron is mounted along the track, in order, that in case of a derailment of a vehicle, the derailed wheel can be safely captured. SUMMARY OF THE INVENTION A principal purpose of the present invention is to create a derailment protection, which safely guides a derailed wheel and thereby, to the greatest possible extent, the purpose includes avoidance of damage to the concrete slab of a rigid track bed. Additional advantages of the invention will be set forth in part in the following description, or may be obvious from the description; or may be learned through practice of the invention. This purpose is achieved by a rigid track bed of concrete, in particular, of precast concrete components, with a slab and a continuous or a multiplicity of fastenings for rails to accommodate track guided vehicles. On the slab parallel to at least one side of at least one rail, a curb is placed as a precast concrete component for the protection of vehicle and for guidance during a derailment of the vehicle. A rigid track bed is made of concrete, especially of precast concrete components, and possesses a slab with fastenings mounted thereon to mount rails for track guided vehicles. Normally the slabs are about 6 meters long, whereby rail fastening units must be placed, separated from one another at distances of about 60 cm. On each slab, then, a multiplicity of rail fastenings are provided. In accord with the invention, to be found on the slab, and parallel to the rail, is an upward directed, precast, curb. This curb serves for the protection of the slab, the rail and, in case of derailment, also the vehicle. The prefabricated concrete part so acts, that in the intervening space between the rail and itself, a derailed wheel of a track guided vehicle is captured and the vehicle or vehicles can be brought to a stillstand in a gradual manner. The curb, which simultaneously runs along beside the rail, exhibits no particularly large opening between its sections, in which the vehicle, i.e. the derailed wheel can be abruptly prevented from rolling to its stop. By means of the evenly guided run of the wheel, in this way damage of the rigid track bed slab and the curb is substantially avoided. Beyond this, the track guided vehicle is thereby prevented from leaving the rigid track bed, whereupon, under certain circumstances, an entire vehicle can overturn. Thereby, since the curb is designed of precast concrete, the curb is granted sufficient structural strength to retain the vehicle. The force load for such capture can reach some 10 metric tons per meter, which is resisted by a precast concrete part made in accord with modern technology. Advantageously, the rail fastenings are placed at support points, especially on upward projections of the underlying slab of the rigid track bed. In this regard, there are specified fastening locations created for the rails, so that the rails can be laid in a very exact alignment. The bottom of the space between the rail and the longitudinal curb, in this invented design, can be raised somewhat higher, so that along this path, an even running height for the derailed wheel is created. By this elevation, an abrupt drop of a wheel from one supporting tie and a lifting to a next tie is avoided. In addition to this advantage, an appropriate design of rail fastenings position avoids damage to the fastenings under a rolling derailed wheel. Since the curb is of precast design, the casting can be easily made to include this protective feature. Particularly advantageous, since the manufacturing costs thereof are low, is to integrate the raised curb into the slab. In this manner, with only one manufacturing step, both the slab and the curb can be made for protection during derailment. No further field mounting labor is necessary, and besides this, the structural strength of the curb is increased by this action, since a firm connection to the massive slab has been created. Derailment protection need not be made in the form of a separate, exchangeable component, since damage to curb and the rigid track bed, when made in the invented design for derailment protection, is only to be feared in very few cases. The integrated manufacture of the curb and the slab is thus advantageous. It is particularly advantageous, if the curb is placed on that side of the rail proximal to the centerline of the track. The derailed wheel, which is diverted toward the center of the track, is then controlled. Additionally, it is obvious, that an additional curb could be provided on the outside of the rail, so that derailed wheels on both sides of the vehicle could travel securely in a guided path between the rails and the curbs. Particularly advantageous and of an inventive nature is a situation wherein the continuity of the curb is intermittently provided with slots running transverse to the longitudinal axis of the slab. These slots can serve for the runoff of rain or melt water which collects on the slab. It is a possibility, that the slot can extend itself through the curb to a point within the slab, then, by this means, stress points of fissures are engendered within the slab. Inevitable cracks can branch out from such slots. However, giving consideration to condition of the slab, such cracking can be controlled. Accordingly, both the fissuring of the curb and of the slab can be specifically regulated. The slotted recesses are so formed, that the over-rolling of the derailed wheel is not particularly disturbed and thus the curb is not damaged. It is of particular advantage, if the slab itself exhibits additional fissure blocking slots, particularly when the slots of the curb find themselves proximal to the fissure protection areas. In this way, a positive control on the general fissure growth is created. An uncontrolled continuance of branching fissures is reliably avoided by the presence of these slots. It has proven itself as particularly advantageous, when the shape of the curb is such, that the upper edge of the curb is above the top surface of the rail, by perhaps about 20 mm. In this way, a derailed wheel, which, because of the effective forces of the derailment hops along off the rail, is very reliably arrested by the curb. The derailed wheel is thus forced to roll between the rail and the curb until it is safely brought to a stillstand. In order to maintain a sufficient spacing between the rail and the sidewall of the curb for the derailed wheel of the track guided vehicle, it is advantageous if the space has a breadth of about 180 mm. Using this dimension, a customary running wheel of a track guided vehicle can be reliably confined, with no fear that the curb or the rail would be damaged, or that the wheel jumps out of the separating space. Obviously, the effective separation can be otherwise dimensioned, if the track guided vehicle possesses wheels, which obviously are wider or narrower than customary. In any case, it is important, that the intervening distance is dimensioned to be sufficiently wide to accommodate the dimensions of a derailed wheel. It is of particular advantage if the curb is made of high strength concrete. With such strength available, the forces to be expected by a derailment, which work against the derailment safety structures, are containable by the concrete curb, without the expectation that the curb itself will be destroyed and that the vehicle, under certain circumstances, can divert itself from the rigid track bed. With high strength concrete, the curb will exhibit such a structural strength, that the generated derailment forces are contained. Where an integrated curb is in use, it is advantageous if the curb is further consolidated with the slab by continuous, steel reinforcement rodding. In derailment incident, this supplementary strengthening will prevent the curb from being torn away from the rigid track bed. Another method of holding to a high structural strength for the concrete curb, is the use of fiber reinforced concrete to enhance the derailment protection of the curb. If an especially high strength concrete is necessary for derailment protection, then it is also possible, that metal structural members can be worked into the curb. Particularly, with an angle bar embedded in the concrete, the edges of the curb are protected. With this supplementary measure, an especially better derailment protection is brought about, even though, for normal usage, a concrete curb is entirely sufficient. If curbs with metal structural members are employed, then it is advantageous, if the continuity of the metal structural member is interrupted in proximity to the described slots. In such a case, assurance is given, that the inherent fissuring of the slab of the rigid track bed cannot bridge over and is thus made inactive. Alternatively, provisions can be made, for metal structural members, particularly rods, to be installed so that they can “prestress” the concrete body, whether slab or curb. If this is done, it becomes possible, that the slab of the rigid track bed can endure load fissuring, without the possibility that bifurcating cracking would extend itself to other than foreseen locations. Advantageously, the curbs are so designed, that the fastenings for the rail are protected from damage. In this matter, it is advantageous, if the bottom of the intervening space between the curb and the rail, is of such a height, that the wheel rolls therein without contacting the rail fastenings. Such a solution is very easy to realize with premixed concrete curbs. Further advantages of the present invention are described in the following embodiments in greater detail. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a cross-section through a slab according to the invention; FIG. 2 shows a profile view of a slab; FIG. 3 shows an alternative embodiment in cross-sections, and FIG. 4 shows a profile view of the slab of FIG. 3 . DETAILED DESCRIPTION Reference will now be made in detail to the presently preferred embodiments of the invention, one or more examples of which are shown in the figures. Each example is provided to explain the invention, and not as a limitation of the invention. In fact, features illustrated or described as part of the embodiment can be used with another embodiment to yield still a further embodiment. It is intended that the present invention cover such modifications and variations. In FIG. 1 is shown a cross-section through a slab 1 of a rigid track bed in the area of a rail 3 . The slab 1 consists of a concrete precast section and carries on its surface a multiplicity of the elevated support points 2 , upon which the rail 3 and its rail fastenings 4 are affixed. This arrangement is entirely suitable for the use of conventional rail fastenings 4 . The fastening may comprise clamps or bolts, which fasten the foot of the rail to the substrate. On the slab 1 is placed a curb 5 . The curb 5 is best integrated with the slab 1 , and thus presents, along with the slab 1 , a single precast concrete component. The curb 5 is made of high strength concrete or may be of fiber reinforced concrete, in order that the applied load in the case of derailment of a track guided vehicle may be contained without additional measures and the derailed wheel may continue a controlled rolling in an intervening space between rail 3 and curb 5 . The curb 5 in the depicted embodiment is placed toward the centerline of the tracks. The second (not shown) rail of the track can likewise be guarded by a second curb 5 , again proximal to the track centerline. By this means, the motion of a derailment of the vehicle is reliably limited in both directions. Such structuring, however, is not required in every case. The curb 5 possesses an upper edge 6 . which is higher than an upper edge 7 of a rail 3 . This difference in elevation provides assurance, that during a derailment, under certain circumstances a hopping, derailed wheel remains safely confined in the intervening space between the rail 3 and the curb 5 . As a difference in the elevations, a dimension of some 20 mm has shown itself to be sufficient. The width of the intervening space between the head of the rail 3 and the inner wall of the curb 5 , at least for common wheels of track guided vehicles, is measured at 180 mm, which is considered sufficient. In this case, the wheel is securely caught therein with directionally controlled roll, and remains so until it is brought to a stillstand. FIG. 2 shows a longitudinal side view of the slab 1 , with a profile of the curb 5 . Illustrated here, the curb 5 is divided by slots 10 in regular succession, approximately 650 mm apart. The slots 10 extend into the slab 1 below and transform themselves into safety slots blocking the random growth of fissures. Inevitable cracks can develop proximal to the safety slots, when the precast slab 1 is laid in place or during its curing period. Therefore, the slot 10 is placed proximal to a fissure-blocking position 11 of the slab 1 . Furthermore, a sinking of the substrate soil can lead to associated fissures, which extend themselves to the safety slots and are there brought under control. Moreover, the safety slots serve for the runoff of rain or melt water which would collect on the slab. The rain or melt water, which collects on the slab, or between the slots can drain from the outer side openings of the slab. FIG. 3 provides an alternative embodiment of a curb 5 . The curb 5 here possesses a raised bottom 12 , which runs from one set of rail fastenings 4 to the next set of rail fastenings 4 in the longitudinal direction of the rails 3 . A wheel 13 , which normally rolls on the rail 3 , in an uncontrolled derailment, would be captured in the intervening space between the rail 3 and the curb 5 . Accordingly, the derailed wheel 13 ′ rolls on the bottom 12 of the curb 5 . In order to avoid damage to the rail fastenings 4 , the bottom 12 is so elevated in relation to the rail fastenings 4 , that the rail fastenings 4 can be rolled over by the derailed wheel 13 ′ without damage. The curb 5 possesses in this exemplary embodiment, a metal structural member 15 on the upper edge 6 , proximal to the rail 3 . This metal structural member 15 serves as a protector of the edge 6 , in order to avoid a breaking off of the upper edge 6 of the curb 5 in a case of an abrupt impact of the wheel 13 thereagainst during a derailment. The curb 5 itself is the actual safety element against derailment damage. FIG. 4 shows a longitudinal side view of the subject of FIG. 3 . From this illustration may be inferred, that the bottom 12 of the curb 5 is placed at such an elevation, that the derailed wheel 13 ′ rolls directly over the rail fastenings 4 , without touching these. Any damage to the rail fastening 4 , and thereby also damage to the rail 3 is thus reliably avoided. The rail fastenings 4 are respectively located in a depression in the bottom 12 and thus do not come into contact with a derailed wheel 13 ′. This is because the wheel 13 ′ rolls from the first partial level of the bottom 12 onto the second partial level of the bottom 12 without dropping so low, that it comes into contact with the fastening apparatus 4 . The present invention is not limited to the described embodiment examples. Other formulations of the curb 5 and the rail fastenings 4 as well as the rail support points can be made at any time. For instance, the curb 5 can be designed exactly in the manner of a second curb (not shown) running parallel at the other side of the slab 1 . This even allows a platform, which could be used for salvage and rescue crews. Beyond this, an additional parallel running curb can be laid on outside of each rail 3 . In this way, an additional derailment safety measure is created. The cross-sectional shape of the curb 5 obviously, can be altered in molding from the shape here illustrated. Moreover, the curb 5 can be bolted to the slab 1 , whereby this would involve a somewhat less stable design than the above described integrated precast construction of the same. In regard to the fastening of the rails, it is possible that one continuous fastening arrangement of the rail can be made on the slab, instead of the fastening the rail at a multitude of positions thereon. A fastening structural member clamps the rail to a provided holding means on the slab. It will be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. It is intended that the present invention include such modifications and variations as come within the scope of the appended claims and their equivalents.	A rigid track consisting of concrete, in particular pre-cast components, comprising a slab with traversing fixing elements, or a plurality of fixing elements arranged thereon, of rails for track-borne vehicles. The inventive rigid track is characterized by a pre-cast concrete component constituting a protuberance that is positioned on the slab, parallel to at least one rail and located on at least one side of the rail. The protuberance acts as a guard and a guide for the vehicle during derailment.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION Adjustable thresholds are known in the prior art and have for their purpose to compensate for unevenness and lack of squareness in doors and door frames, as well as to provide an improved doorway seal. Some examples of the patented prior art are shown by U.S. Pat. Nos. 3,374,579; 3,690,037 and 3,762,100. The general objective of this invention is to improve on the prior art adjustable thresholds by rendering them less complicated and therefore less costly and by increasing their efficiency of operation and ease of installation. Generally, the devices of the prior art have not been widely accepted because of undue complexity and cost and because they are difficult to install and properly adjust and lack the sturdiness of construction required for long service with practically no maintenance. The present invention seeks to overcome these and other deficiencies of the prior art, and various features and advantages of the invention will become apparent during the course of the following description. BRIEF DESCRIPTION OF DRAWING FIGURES FIG. 1 is a fragmentary perspective view in cross section of an adjustable threshold embodying the present invention. FIG. 2 is an enlarged fragmentary vertical cross section taken through the threshold and showing the adjustable threshold member in a full down position for shipment. FIG. 3 is a similar sectional view showing the adjustable threshold member in a raised use position. FIG. 4 is a plan view of the invention, partly in section. FIG. 5 is a vertical cross section taken longitudinally through the adjustable threshold member and showing the captured adjusting or leveling screws thereof with the threshold member in a down position as in FIG. 2 and taken on line 5--5 of FIG. 4. FIG. 6 is a view similar to FIG. 5 showing the threshold member in an adjusted and level position relative to a door. DETAILED DESCRIPTION Referring to the drawings in detail wherein like numerals designate like parts, the adjustable threshold according to the invention comprises a vertically adjustable threshold member or bar 10 preferably formed of hard wood, such as oak. The bar or member 10 has a shallow longitudinal recess 11 in its bottom face for a purpose to be described and is generally rectangular in cross section, as illustrated. However, the outer longitudinal side wall 12 of the adjustable threshold member is inclined slightly from the true vertical to provide a wedging or squeezing action on the longitudinal skirt 13 of an adjacent compressible rubber-like seal 14 as the threshold member 10 is adjusted upwardly. The top face of the member 10 is recessed as at 15 to receive the flat heads 16 of adjusting or leveling screws 17, whose threaded shanks are received by T-nuts 18 anchored within openings of a sill filler or base member 19. The screw heads 16 are flush with or slightly below the top face of the adjustable threshold member 10, as shown in FIGS. 2 and 3. The lower ends of the T-nuts 18 are flared at 20 to prevent their retraction from the filler member 19 during the adjustment of the threshold member 10. The adjusting or leveling screws 17 have intermediate rigid flat plates or washers 21 affixed thereto by welding or the like and these elements are received within the bottom recess 11 of the adjustable member 10 and maintain the screws 17 captive on the member 10 although freely rotatable thereon to allow adjusting with a screwdriver. A wooden water stop member 22 abuts the interior longitudinal edge of threshold member 10 and also has a horizontal shoulder 23 underlying the member 10, FIGS. 2 and 3. The shoulder 23 is flush with the top face of sill filler 19, FIGS. 2 and 3, and the heads 24 of T-nuts 18 are similarly flush with the top face of member 19. It may be seen that the adjustable threshold member 10 is trapped at all times between the water stop 22, which is a fixed member, and the compressible seal 14. The adjustable threshold further comprises a preferably extruded aluminum sill 25 having dependent tines 26 which are embedded in the filler member 19 when the threshold is installed. An exterior dependent flange 27 of sill 25 rests on the top edge of a wooden finishing board or strip 28, as shown in FIG. 1. A moisture-proof barrier sheet 29 is preferably intervened between the finishing strip 28 and adjacent base member 30, and a top extension 31 of the barrier sheet is clamped as at 32 between the sill 25 and filler member 19. The soft compressible seal 14 has a rounded top portion which bridges the space between sill member 25 and adjustable threshold member 10 and also forms a good seal therewith. A dependent body 33 of the compressible seal 14 is held captive in a compartment of the extruded sill 25 near the interior thereof, as shown. The dependent skirt 13 of the seal adjacent to the adjustable member 10 is squeezed between the slightly angled face 12 of the adjustable threshold member and the adjacent fixed vertical web 34 of sill 25. A horizontally swinging door 35 is shown in FIG. 1 above the adjustable threshold member 10, and equipped with a lower edge seal or weather strip 36 which wipes the member 10 when the door is closed. When the assembly, consisting of elements 19, 22, 10, 14, 25, 17 and 18, is shipped, the member 10 is preferably in the full down position shown in FIG. 2 for compactness and so that there will be no loose components. During installation, however, the leveling screws 17 are utilized as required to raise and level the member 10 so as to compensate for irregularities in the door and doorway. FIG. 6 illustrates the manner in which one of the adjusting screws 17, namely the right hand screw in FIG. 6, may be utilized to raise one end of the member 10 a greater distance above the fixed filler member 19 than the opposite end thereof. In some instances, the reverse may prevail and in still other instances both ends of the member 10 may require adjusting upwardly substantially the same amounts. In this respect, the invention is very versatile and at the same time very simple. The construction is sturdy and there is no possibility for the component parts to be lost during shipment or otherwise separated. Once properly installed and adjusted, the parts will remain properly positioned for years with minimum attention or no attention. The advantages of the invention should now be apparent to those skilled in the art without the necessity for further description herein. It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.	A vertically adjustable threshold member or bar is shipped in a down position and is adjusted upwardly at installation by attached shouldered leveling screws engaging within flared T-nuts of base or sub-structue. A compressible seal is interposed between the outer longitudinal edge of the adjustable threshold member and an extruded metal sill. The outer longitudinal edge of the threshold member is beveled slightly for increasing pressure on seal as threshold member is raised.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of U.S. patent application Ser. No. 15/059,935 filed Mar. 3, 2016 the contents of which are herein incorporated by reference. This application also claims the benefit of priority of U.S. provisional application No. 62/127,615, filed Mar. 3, 2015 the contents of which are herein incorporated by reference. BACKGROUND OF THE INVENTION [0002] The present invention relates to architectural molding, and more particularly, to architectural moldings placed between adjoining sections of drywall. [0003] Typical drywall installations generate significant amounts of dust and debris when sealing the joints between adjoining sections of drywall. A gypsum joint compound, or “mud”, is typically applied to the gaps between adjoining drywall sections. Many times, a tape is applied to help span the gap and provide a surface for the mud compound. [0004] Once the joint compound has dried, is then sanded to provide a seamless wall surface. However, the process of finishing drywall seams represents a substantial portion of the labor and materials associated with typical drywall installation and repairs. Moreover, the released gypsum particulates from the sanding present a health hazard to the workers. [0005] Some architectural molding systems are available in the art, however, they still contemplate the use of joint compound or sealers. Once installed, none provide accessibility to the area beneath the molding without the subsequent removal of the joint compounds and sealers. Moreover, the limited systems available do not eliminate the need to tape and finish at least a portion of the drywall. [0006] As can be seen, there is a need for a system of components that relies on a mechanical friction fit assembly for easy installation and removal of architectural moldings in the event of future renovation projects or to provide access to the cased areas for other repairs. SUMMARY OF THE INVENTION [0007] In one aspect of the present invention, an architectural molding assembly is provided for a mud free joint between adjacent wall boards applied to a wall surface of a room. The architectural molding assembly includes an elongate bracket having a flattened V-shape interior surface defined along a longitudinal length of the bracket. The angle of the V-shape is dimensioned to conform the interior surface to a tapered edge surface extending along a longitudinal length of the adjacent wall boards. An apex of the elongate bracket is configured to be positioned along adjacent edges of the adjacent wall boards. The bracket includes an upturned latching end defined along first and second lateral sides of the interior surface. The upturned latching ends are configured for a snap-fit engagement with a corresponding latch finger defined in a molding to enclose the elongate bracket. [0008] In other aspects of the invention the architectural molding assembly includes a molding having a room facing surface, a wall facing surface, and lateral side surfaces. An inwardly turned latch finger extends from an intermediate portion of the wall facing surface between the lateral side surfaces and a centerline of the molding. The molding may also include a ridge extending along a longitudinal centerline of the wall facing surface of the molding. The ridge is configured to contact the vertex of the interior surface with the molding attached to the bracket. An engagement channel may be defined between the inwardly turned latch fingers and the wall facing surface. A hook may be defined at a tip of the upturned latching end, such that the hook is configured for the snap-fit engagement in the engagement channel. [0009] In other aspects of the invention, an inwardly turned edge of the side facing surfaces is dimensioned so that it is positioned in abutment with a flat wall board surface adjacent to the tapered edge section of the wall board. In some embodiments, a channel is defined in an interior surface of the side surfaces. [0010] The architectural molding assembly may also include a molding having a room facing surface, a wall facing surface, lateral side surfaces; and an inwardly turned latch finger extending from the lateral side surfaces of the molding that is configured for the snap-fit engagement with the upturned latching end of the bracket. The molding may also have an inwardly turned edge defined along the lateral side surfaces that is dimensioned so that it is positioned in abutment with a flat wall board surface adjacent to the tapered edge section of the wall board. [0011] A plurality of holes may be disposed in a spaced apart relation along the longitudinal length of the interior surface of the bracket. The holes may receive a fastener to secure the bracket to a support member of the wall. [0012] Yet other aspects of the invention include a method of removably applying an architectural molding for a mud free joint between adjacent wall boards in a wall surface of a room. The method includes applying an elongate bracket having a V-shape interior surface defined along a longitudinal length of the bracket, an upturned latching end defined along first and second lateral sides of the interior surface, wherein the angle of the V-shape is dimensioned to correspond to a tapered edge surface extending along a longitudinal length of the adjacent wall boards. An apex of the elongate bracket may be positioned along the adjacent edges of the wall boards. A fastener may be installed through the bracket to secure the bracket to the wall. [0013] The method includes providing a molding having a room facing surface, a wall facing surface, and lateral side surfaces; and an inwardly turned latch finger extending from an intermediate portion of the wall facing surface between the lateral side surfaces and a centerline of the molding. The molding may then be attached to the bracket wherein the upturned latching end of the wall bracket is secured in a snap-fit engagement with the latch finger defined in the molding to enclose the elongate bracket and conceal the tapered edge surface of the adjacent wall boards. [0014] These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 illustrates architectural moldings of the present invention applied to finish a room. [0016] FIG. 2 is an enlarged detail of an inside corner capital and crown molding. [0017] FIG. 3 is an enlarged detail of an inside corner floor base pedestal and corner. [0018] FIG. 4 is an enlarged detail of a floor base and wall molding. [0019] FIG. 5 is cross sectional view of a floor base and bracket. [0020] FIG. 6 is a view of a floor base and bracket. [0021] FIG. 7 is a cross sectional view of a wall molding and bracket. [0022] FIG. 8 is a perspective view of a wall molding and bracket. [0023] FIG. 9 is a view of an inside corner floor base pedestal. [0024] FIG. 10 is a perspective view of an inside corner floor base pedestal. [0025] FIG. 11 is a cross sectional view of an inside corner capital. [0026] FIG. 12 is a perspective view of an inside corner capital. [0027] FIG. 13 is a cross sectional view of a ceiling beam and bracket. [0028] FIG. 14 is a perspective view of a ceiling beam and bracket. [0029] FIG. 15 is a cross sectional view of an inside vertical corner molding. [0030] FIG. 16 is a perspective view of an inside vertical corner molding. [0031] FIG. 17 is a cross sectional view of a crown molding and bracket. [0032] FIG. 18 is a perspective view of a crown molding and bracket. DETAILED DESCRIPTION OF THE INVENTION [0033] The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. [0034] Broadly, an embodiment of the present invention provides a system for finishing the walls of a room without the need for drywall joint compound. The components of the system generally include a bracket and a molding cover. The bracket is applied along a seam between one or more adjacent wall, ceiling, and floor members. The molding cover is configured for a snap fit connection to the bracket member to provide a desired architectural finish to the seams within the room. The moldings and brackets are preferably formed by an extrusion of any suitable material. [0035] As best seen in reference to FIG. 1 , a system and method finishing a room with an architectural molding is illustrated. The system of architectural moldings of the present invention permit the finishing of drywall panels without the need for applying or sanding a joint compound. The architectural moldings may include a floor base molding assembly 30 that is applied along a seam between a wall and a floor of a room or structure, as seen in the detail view of FIG. 4 . A wall molding assembly 40 that may be applied along a seam between adjacent wall panels, such as drywall panels is also shown in reference to FIG. 4 . As seen in reference to FIG. 3 , an inside corner flor base pedestal 50 is intended to be applied to an inside corner in a space between the ends of adjacent floor base moldings 30 . As seen in reference to FIG. 2 , an inside corner capital 60 is intended to be applied to an inside corner between the ends of adjacent crown molding assemblies 90 applied along the seam between the wall panel and a ceiling panel of the room. When needed, a ceiling beam assembly 70 is provided for covering the seams between adjoining ceiling panel members. An inside vertical corner molding assembly 80 may be applied to an inside corner seam between adjoining walls. [0036] In reference to FIGS. 5 and 6 , the floor base assembly includes an interlocking pair of elongate members including a floor base bracket member 31 and a floor base molding 30 . The floor base bracket member 31 is defined with a plurality of channels to provide added strength along the length of the bracket member 31 , and provide for mounting the components of the floor base assembly 30 to the bracket 31 . An upper edge surface of the floor base bracket 31 is spaced away from a wall mounting surface of the bracket. A lower edge surface of the bracket 31 is formed with and upturned wall facing lip 36 extending along the longitudinal length of the bracket 31 . [0037] The floor base bracket member 31 has a plurality of holes 37 disposed in a spaced apart relation in a wall facing channel face formed along a longitudinal length of the floor bracket member 31 . The holes 37 receive a fastener, such as a screw, nail, or the like, to secure the bracket assembly to the structural members along the base of the wall. [0038] A floor base spacer 32 may be secured to the floor base bracket member 31 by a plurality of tabs, or pins 34 extending from a wall facing surface of the spacer 32 . The tabs 34 are received through a plurality of holes (not shown) that are defined in a spaced apart relation along a room facing channel face of the bracket 31 . The tabs 34 secure the floor base spacer 32 to the floor base bracket member 31 . The floor base spacer 32 may include a plurality of grooves defined in a room facing surface of the spacer. The grooves form a plurality of extensions that are adapted for shock absorption for items that may strike the base molding assembly 30 . [0039] The floor base molding 30 may be formed so as to cover and substantially enclose the bracket 31 . The top edge of the floor base molding 30 is provided with a finger 38 extending from a wall facing surface of the molding 30 . The finger 38 extends so as to be positioned adjacent or in abutment with the wall surface. An arm 33 runs along the longitudinal of the base molding 30 subjacent to the finger 38 . The arm 33 defines a channel along an interior surface of the base molding 30 and is adapted to receive the upper edge surface of the floor base bracket 31 so as to retain the upper portion of the base molding with the bracket 31 . [0040] A lower edge surface of the base molding 30 is defined with a latch 35 with a room facing protrusion extending from the latch 35 . The protrusion is adapted to engage with the wall facing lip 36 of the bracket 31 to engage the base molding 30 in a snap-fit manner. A toe molding arm extends from a room facing surface of the molding 30 to define a toe molding along the longitudinal length of the base molding 30 . The toe molding arm is shaped to conceal the wall facing lip 36 with and end thereof positioned adjacent to the floor. [0041] The base molding 30 may also have a ledge formed at an upper portion of thereof that extends from the wall facing surface of the molding 30 . The ledge is adapted to rest upon a top room facing edge of the spacer 32 and the face of the spacer may be positioned against the wall facing surface on the interior of the molding 30 . [0042] As seen in reference to FIGS. 1, 4, 7 and 8 , a wall molding 40 and bracket 43 are provided for covering the gaps between adjacent wall boards mounted in parallel, such as along the span of a wall. The wall molding bracket 43 has a slightly tapered V-shaped wall facing surface that is dimensioned to conform to the tapered edge portions extending along the longitudinal length of a conventional gypsum wall board. An apex 47 of the V-shaped surface may be positioned to center the wall molding bracket 43 in the adjoining edges or gap between adjacent gypsum wall boards that are mounted in the wall surface. The wall molding bracket 43 has upturned ends 46 formed along the lateral sides thereof for a snap-fit engagement with a corresponding latch finger 44 defined in the wall molding 40 . [0043] The molding 40 has a substantially flat room facing surface with outwardly turned side facing surfaces 41 . An inwardly turned edge of the side facing surfaces 41 are dimensioned so that they are in abutment with a flat surface of the wall board adjacent to the tapered edge section of the wall boards. A channel 48 may be defined in an interior surface of the side surfaces 41 to provide structural strength and a fulcrum for securing the molding 40 to the bracket 43 . [0044] A ridge 42 is formed and extends along a midline of the wall facing surface of the molding 40 . The pair of opposed inwardly facing latch fingers 44 are formed along an intermediate line of the wall facing surface of the wall molding 40 . The latch fingers 44 define an engagement channel 45 oriented towards the centerline of the molding 40 . The upturned ends 46 of the bracket are adapted to be received by the engagement channel 45 of and the latch fingers 44 in a snap-fit arrangement to secure the wall molding 40 to the bracket 41 . [0045] The ridge 42 is dimensioned to contact the bracket 43 at the apex 47 with the molding 40 operatively attached to the bracket 43 . The ridge 42 may be configured to impart a slight flexing moment to the molding 40 so that the latch fingers 44 maintain the molding 40 in a snug fitting arrangement with the bracket 41 . A plurality of holes 49 , seen in reference to FIGS. 1 and 4 are disposed in a spaced apart relation along the length of the wall bracket 43 to receive a fastener, such as a screw or nail there through to secure the bracket 43 to a structural member in the wall. [0046] As seen in reference to FIGS. 9 and 10 , the inside corner base pedestal molding 50 is depicted with an inside corner base support 55 . The inside corner base pedestal 50 is formed to provide continuity of the floor base moldings 30 . The corner base support 55 is installed in a corner of wall structure adjacent to the floor. The corner base support has a plurality of ribs 54 to provide structural support. A plurality of apertures 53 may be defined along a face of the support 55 for engagement with cooperating fingers defined on an interior, wall facing surface of the molding 51 . [0047] As seen in reference to FIGS. 11 and 12 , an inside corner capital molding 60 is provided for a corner of a room between adjoining, perpendicular wall surfaces. The inside corner capital molding is adapted for snap fitting with an inside corner bracket 83 that is also utilized with an inside vertical corner molding. An interior wall facing surface of the corner capital molding 60 has a pair of attachment fingers 67 adapted for snap fitting engagement with a pair of inwardly facing hooked ends 65 of the bracket 83 . [0048] As seen in reference to FIGS. 13 and 14 , a ceiling beam molding 70 and ceiling beam bracket 73 is provided as an option to utilizing the wall molding 40 of FIGS. 7 and 8 . The beam molding 70 has a greater depth than the wall molding 40 . The beam molding 70 may have a channel 71 defined in a room facing surface of the molding 70 . On an interior surface of the molding a pair of latch fingers 74 are formed along the longitudinal length of the molding 70 . [0049] Like the wall molding bracket 43 , the ceiling beam bracket 73 has a pair of upturned arms 77 with a slightly hooked portion 75 defined along the longitudinal length of the bracket 73 . The latch fingers 74 have protrusions adapted to engage with the hooked portion 75 of the upturned arms 77 to secure the beam molding to the bracket 73 . The bracket 73 is provided with a plurality of spaced apart holes 76 to receive a fastener, such as a screw or a nail to secure the bracket 73 to a ceiling structural member. The beam molding 70 may define a cavity 72 . [0050] As seen in reference to FIGS. 15 and 16 an inside corner vertical molding assembly includes an inside corner molding 80 and an inside corner molding bracket 83 . The molding 80 has lateral side flanges 81 and 82 defined at the ends of an arcuate mid portion to give the appearance of a conventional corner molding. The arcuate mid portion may be either concave or convex. A pair of latching fingers 85 having protrusions on an outer lateral surface of the latching fingers 85 are defined along a longitudinal length of the molding 80 . The bracket 83 is formed with substantially perpendicular sidewalls 83 extending from a corner engaging midsection. The corner bracket 83 has bent arm portions 84 and opposed hook portions 86 defined along the longitudinal length of the bracket. The opposed hook portions 86 are adapted to engage with the protrusions of the latching fingers 85 so that the molding may be snap fit to the bracket 83 . When attached to the bracket 83 the molding 80 and bracket define an interior cavity 87 . [0051] As seen in reference to FIGS. 17 and 18 a crown molding assembly is provided having a crown molding 90 and a crown molding bracket 93 . The crown molding 90 has lateral side flanges 91 and 92 defined at the ends of an arcuate mid portion to give the appearance of a conventional crown molding. The arcuate mid portion may be either concave or convex. A pair of latching fingers 96 having protrusions on an outer lateral surface of the latching fingers 96 are defined along a longitudinal length of the crown molding 90 . The bracket 93 is formed with substantially perpendicular sidewalls extending from a corner engaging midsection. The crown molding bracket 93 has bent arm portions 95 and opposed hook portions 94 defined along the longitudinal length of the bracket 93 . The opposed hook portions 94 are adapted to engage with the protrusions of the latching fingers 96 so that the crown molding may be snap fit to the crown molding bracket 93 . When attached to the bracket 93 the crown molding 90 and bracket define an interior cavity 97 within the assembly. [0052] As indicated, the architectural molding system of the present invention provides for a complete fitting to a room that may be applied to finish the seams between adjoining drywall panels without the use of a joint compound and the associated particulate hazards. According to the system of the present invention, the wall surfaces may also be treated, such as with paint, wall paper, or other treatments before architectural members of the present invention are installed. This will protect the moldings from being marred with paint or paste drippings. [0053] To install the system, the room may first be fitted with the attachment brackets designed to the particular part of the room. The length of the brackets are cut to accommodate the respective corner components, whether a floor base pedestal or a corner capital and their associated supports. The brackets are secured to the structural members of the room with a fastener, such as a screw or a nail. Once the respective brackets have been installed, the associated moldings may be cut to length and snap fit to their corresponding brackets. [0054] In the event that the room needs to be redecorated, the moldings may be removed from the brackets. The walls may then be retreated while again protecting the moldings from being damaged or marred by spillage or drippings. Once the wall treatment has been applied the moldings may be returned to the brackets. Similarly, if the interior of the walls need to be accessed for plumbing, ventilation, or wiring, the moldings and brackets may be removed and reutilized. The wall panels may be removed without significant destruction or demolition. In like manner, should a molding become damaged, particularly for the floor base moldings, it may be readily replaced without the need for carpentry and painting. [0055] It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.	A fully integrated system of accessible architectural molding which eliminates the need to tape and finish drywall. The system of components relies on a mechanical friction fit assembly that allow for easy installation and removal for future renovations or access to the chase areas of a wall. A molding assembly includes a V-shaped bracket dimensioned to be received in the tapered edge surfaces of adjacent wall boards and a molding secured to the bracket in a snap-fit engagement to conceal the tapered edge surfaces.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION [0001] The present invention relates to a method and apparatus for varying the transmission of light through said apparatus, where the transmission is a controllable function of the angle of light incidence. BACKGROUND OF THE INVENTION [0002] LCD or liquid crystal displays have found widespread use in modern television and computer screens, wristwatches, calculators and the like. A large proportion of modern LCD displays are based on the twisted nematic liquid crystal due to Helfirch and Schadt (Swiss patent CH532261). The orientation of light entering the device is twisted by liquid crystals which are oriented in a spiral or corkscrew fashion. Due to polarizers at the entrance and exit of the device, only light that is thus twisted will exit the device. Upon application of an electric field normal to the liquid crystal plane ('up' or ‘down’ the stairs), the ability of the liquid crystal to twist light orientation is impaired, blocking light from passing through the device and causing the device to appear darker shades of grey for increasing fields, eventually reaching black for a high enough field. Many such individual devices can be fabricated in close proximity to form an LCD screen. Due to the directional nature of the twisted nematic liquid crystals, light incoming from directions off-normal will be less well modulated by the liquid crystal effect mentioned above. Therefore the viewing angle e.g. of laptop screens is reduced. Great effort has been expended to increase the viewing angle of such devices. However this effect can actually be used to advantage, by effectively blocking the light incident from certain angles and allowing the rest to pass. This use of the directional nature of light absorption by liquid crystals is novel and as will be shown below is of great utility in several applications. In brief, since the disclosed apparatus can block incoming light from a particular direction (such as that of the sun) while passing light from other directions, it is capable of reducing glare and increasing the dynamic range of a scene viewed by a camera, a driver, a pilot, a house occupant, etc. Since the system is electronically controlled, an open- or closed-loop feedback system can modify the direction of greatest light attenuation adaptively to track bright objects and keep them blocked. [0003] U S patent application 20060209250 discloses a beam steering device using a liquid crystal with an array of back electrodes. Voltages are applied to the array to cause a desired phase distribution across the array, the distribution being selected to steer a beam incident upon the array into a desired direction. Reflective elements are disposed to reflect light incident in the spaces between the electrodes to reduce losses and to smooth the transitions in phase between adjacent electrodes. However the system is not adapted for the selective transmission or absorption of light based on angle of incidence, but rather to steer a beam incident from a known direction in a controlled fashion. [0004] European patent EP0151703 discloses a directional filter for ambient light constructed from a thin base strip of indeterminate length and having an opaque surface. The strip is wound into a roll having a plurality of convolutions and sections are cut from the face of the roll. A pair of sections are disposed so that their convolutions are in an orthogonal configuration, and are sandwiched between a pair of glass plates having non-reflective outside surfaces. Channels are thereby provided, which impart directional characteristics to the ambient light. However the system is not adapted for the selective transmission or absorption of light based on angle of incidence, but rather to passively impart directional characteristics to the incoming light. [0005] Similarly European patent EP0658780 discloses a directional filter, characterized by a plurality of lamellae which form mutually parallel beam wells, the interspaces being filled by transparent support bodies whose refractive index causes the incident light to be refracted towards the normal on the plane of incidence. Again the system is not adapted for the selective transmission or absorption of light based on angle of incidence, but rather to passively impart directional characteristics to the incoming light. Patents EP0122830 and U.S. Pat. No. 4,621,898 follow similar lines to EP0658780. [0006] Hence, a system for a directional filter is still a long felt need. BRIEF DESCRIPTION OF THE DRAWINGS [0007] In order to understand the invention and to see how it may be implemented in practice, a plurality of embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which [0008] FIG. 1 schematically presents a standard twisted nematic liquid crystal display (LCD); [0009] FIGS. 2 a - 2 b schematically illustrate the operation of a standard LCD; [0010] FIG. 3 schematically illustrates one embodiment of the present invention, with multiple front and back electrodes; [0011] FIGS. 4 a - c schematically illustrate a sequence of applied voltages and the spatial pattern required to produce a LC orientation parallel to the faces of the LC layer; [0012] FIG. 4 d . schematically illustrates the applied electric field of FIGS. 4 a - c; [0013] FIGS. 5 a - 5 c illustrate an example for further manipulations of electric field; [0014] FIG. 6 illustrates a two dimensional control of the LC directions by using a two-dimensional array of electrodes; [0015] FIG. 7 illustrates fields with components in the direction parallel to the face of the LC layer are obtained by using resistive, current-carrying electrodes; [0016] FIG. 8 illustrates another embodiment of the present invention in which directional filter using a PDLC is used; [0017] FIG. 9 illustrates the transmission of light that is polarized at the xy plane as function of incidence angle in some of the PDLC based embodiments. [0018] FIG. 10 illustrates an example of a privacy-maintaining window. SUMMARY OF THE INVENTION [0019] It is one object of the present invention to provide a multi layer directional filter comprising: a. a front polarizer; b. a front glass plate provided with a plurality of transparent, individually addressable upper electrodes and addressing lines, said front glass plate being disposed behind said front polarizer; c. a front transparent insulating layer, said front transparent insulating layer being disposed behind said front glass plate; d. a middle liquid crystal layer containing liquid crystal molecules, said liquid crystal molecules having an electric dipole moment, said middle liquid crystal layer being disposed behind said front transparent insulating layer; e. a hind transparent insulating layer, said hind transparent insulating layer being disposed behind said middle liquid crystal layer; f. a hind glass plate provided with a plurality of transparent, individually addressable lower electrodes and addressing lines, said hind glass plate being disposed behind said transparent insulating layer; g. a hind polarizer, said hind polarizer being disposed behind said hind glass plate; and, h. control circuitry adapted to provide sequences of voltage patterns to said electrodes of said front glass plate and said hind glass plate, said control circuitry being adapted to create electric fields at controllable (i) positions, (ii) directions in space; and, (iii) magnitude; wherein said control circuitry is adapted to control the directions of stable equilibrium of said liquid crystals, hence controlling the directions of incidence of maximal light absorption for each pixel individually such that the light coming from said direction of incidence is substantially absorbed whilst light coming from all other directions is substantially transmitted. [0029] It is another object of the present invention to provide the directional filter as defined above, wherein said front and back insulating layers are additionally provided with a series of grooves in the directions of said front and back polarizers, respectively. [0030] It is another object of the present invention to provide the directional filter as defined above, wherein said electrodes are composed of indium tin oxide. [0031] It is another object of the present invention to provide the directional filter as defined above, wherein said transparent insulating layers are comprised of polyimide material. [0032] It is another object of the present invention to provide the directional filter as defined above, wherein said individually addressable upper and lower electrodes each assume two-dimensional configurations of rows and columns, and wherein said control circuit addresses electrodes belonging to a given row together and applies a single common voltage to all said electrodes of said row in a given phase, and in other temporal phases electrodes belonging to the same column are addressed together and supplied with a common voltage, allowing for two-dimensional control over said direction of incidence of maximal light absorption. [0033] It is another object of the present invention to provide the directional filter as defined above, wherein the voltages applied to a subset of said individually addressable upper and lower electrodes is of a magnitude less than that required for complete alignment of liquid crystal molecules' orientations parallel to the applied field, thereby further modifying said direction of incidence of maximal light absorption. [0034] It is another object of the present invention to provide the directional filter as defined above, wherein said electric field, magnitude and direction is independently controlled by said control circuitry. [0035] It is another object of the present invention to provide the directional filter as defined above, wherein said electric field magnitude and direction is shared by groups of electrodes (pixels). [0036] It is another object of the present invention to provide the directional filter as defined above, wherein said groups of electrodes are adjacent. [0037] It is another object of the present invention to provide the directional filter as defined above, said groups of electrodes occupy arbitrary locations. [0038] It is another object of the present invention to provide the directional filter as defined above, wherein the entire set of said upper electrodes are addressed together, and/or wherein the entire set of said lower electrodes are addressed together. [0039] It is another object of the present invention to provide the directional filter as defined above, wherein said voltage pattern comprises a set of N distinct voltages applied to subsets of said individually addressable upper and lower electrodes, where N is an integer greater than zero. [0040] It is another object of the present invention to provide the directional filter as defined above, wherein said voltage pattern additionally comprises a set of M distinct patterns applied over time, where M is an integer greater than zero. [0041] It is another object of the present invention to provide the directional filter as defined above, wherein said front polarizer is oriented with a polarization direction perpendicular to that of said hind polarizer. [0042] It is another object of the present invention to provide the directional filter as defined above, wherein said front polarizer is oriented with a polarization direction parallel to that of said hind polarizer. [0043] It is another object of the present invention to provide the directional filter as defined above, wherein said front polarizer is oriented with a polarization direction aligned in an arbitrary direction with respect to said hind polarizer. [0044] It is another object of the present invention to provide the directional filter as defined above, wherein said addressing lines on said upper electrodes are oriented perpendicular to the said addressing lines of said lower electrodes. [0045] It is another object of the present invention to provide the directional filter as defined above, wherein said directional filter is additionally provided with a power source selected from a group consisting of: photovoltaic cells, primary voltaic cells, secondary voltaic cells, and one or more adapters facilitating connection to external power sources. [0046] It is another object of the present invention to provide the directional filter as defined above, wherein said directional filter is additionally provided with a direction-sensitive light detector in communication with said control circuitry, said control circuitry being adapted to utilize the direction and intensity information obtained from said direction-sensitive light detector to change said direction of incidence of maximal light absorption. [0047] It is another object of the present invention to provide the directional filter as defined above, wherein said control circuitry is adapted for minimizing flare effect. [0048] It is another object of the present invention to provide the directional filter as defined above, wherein said control circuitry controls said direction of incidence of maximal light absorption by means of a closed loop algorithm adapted for minimizing error in said direction of incidence of maximal light absorption. [0049] It is another object of the present invention to provide the directional filter as defined above, wherein the pixels are addressed by a pixel addressing mechanism selected from a group consisting of: passive, active, TFT, or combinations thereof. [0050] It is another object of the present invention to provide the directional filter as defined above, wherein a first spatial axis of the electric field pattern and subsequent liquid crystal alignment is controlled by applying directional fields using a spatial pattern of voltages in the plane of said first axis, while a second spatial axis the electric field pattern and subsequent liquid crystal alignment is controlled by applying directional fields using a spatial pattern of voltages in the plane of said second axis. [0051] It is another object of the present invention to provide the directional filter as defined above, wherein one spatial axis of the electric field pattern is controlled by applying a directional field using a spatial pattern of voltages, while the other (orthogonal) spatial axis is controlled by varying the magnitude of applied voltage, thereby achieving two-dimensional control without requiring individual addressing of each pixel in both dimensions. [0052] It is another object of the present invention to provide the directional filter as defined above, wherein the sequence of voltages applied to said top and bottom electrodes occurs in several temporal phases and in repetitive patterns that induce at the liquid crystal layer electric fields that in a given temporal phase are oriented nearly in the same absolute direction, and wherein the polarity of said electric fields may be reversed without affecting the said absolute direction. [0053] It is another object of the present invention to provide the directional filter as defined above, wherein two or more of said voltage patterns applied to said top and bottom electrodes induce at the liquid crystal layer electric fields that have nearly the same said absolute direction and induce temporal averages of the local absolute magnitudes of the electric fields along the liquid crystal layer that are relatively uniform. [0054] It is another object of the present invention to provide the directional filter as defined above, wherein the sequences of voltages applied to the top and bottom electrodes is alternating in several temporal phases so as to induce at the liquid crystal molecules alternating rotational torques in a rate fast enough relative to the rotational response time of the liquid crystal molecules so that the said molecules will assume a desired spatial orientation of their long axes. [0055] It is another object of the present invention to provide the directional filter as defined above, wherein said voltage patterns applied to the top and bottom electrodes alternate between several phases so as to induce at the liquid crystal molecules alternating rotational torques in a rate fast enough relative to the rotational response time of the liquid crystal molecules so that the spatial orientations of the long axes of said molecules will be stable in time. [0056] It is another object of the present invention to provide the directional filter as defined above, wherein said voltage patterns applied to said top and bottom electrodes alternate in several temporal phases so as to induce on said liquid crystal molecules alternating rotational torques that orient the long axes of said molecules in a uniform desired spatial direction throughout the volume of the said liquid crystal layer. [0057] It is another object of the present invention to provide the directional filter as defined above, wherein said directional filter has a shape selected from a group consisting of: planar, simple curve, compound curve. [0058] It is another object of the present invention to provide the directional filter as defined above, wherein said upper and lower electrodes take the form of parallel, conductive stripes. [0059] It is another object of the present invention to provide the directional filter as defined above, wherein said sequences of voltage patterns are applied in time periods less than the mechanical rotational time constant of said liquid crystal molecules. [0060] It is another object of the present invention to provide a multi layer directional filter comprising: a. a front glass plate provided with a plurality of transparent, individually addressable upper electrodes and addressing lines; b. a front transparent insulating layer, said front transparent insulating layer being disposed behind said front glass plate; c. a middle liquid crystal layer containing droplets of liquid crystal molecules dispersed in a polymer matrix, said middle polymer-dispersed liquid crystal layer being disposed behind said front transparent insulating layer; d. a hind transparent insulating layer, said hind transparent insulating layer being disposed behind said middle polymer-dispersed liquid crystal layer; e. a hind glass plate provided with a plurality of transparent, individually addressable lower electrodes and addressing lines, said hind glass plate being disposed behind said transparent insulating layer; f. control circuitry adapted to provide sequences of voltage patterns to said electrodes of said front glass plate and said hind glass plate, said control circuitry being adapted to create electric fields of controllable (i) positions, (ii) directions in space; and, (iii) magnitudes; wherein said control circuitry is adapted to control the direction of incidence of maximal light scattering for each pixel individually such that the light coming, from said direction of incidence is substantially scattered whilst light coming from all other directions is substantially transmitted. [0067] It is another object of the present invention to provide the directional filter as defined above, wherein said upper and lower electrodes take the form of parallel, conductive stripes. [0068] It is another object of the present invention to provide the directional filter as defined above, wherein said sequences of voltage patterns are applied in time periods less than the mechanical rotational time constant of the liquid crystal molecules. [0069] It is another object of the present invention to provide the directional filter as defined above, wherein said polymer-dispersed liquid crystals' molecules are rotated in time by means of said voltage patterns applied by said control circuitry. [0070] It is another object of the present invention to provide the directional filter as defined above, wherein said polymer-dispersed liquid crystals molecules' orientations are switched in time by means of said voltage patterns applied by said control circuitry. [0071] It is another object of the present invention to provide the directional filter as defined above, wherein said polymer-dispersed liquid crystals are stationary and directionally controlled by means of said voltage patterns applied by said control circuitry. [0072] It is another object of the present invention to provide the directional filter as defined above, additionally supplied with side electrodes in communication with said control circuitry, wherein said side electrodes can create electric fields parallel to the plane of the layers of the device. [0073] It is another object of the present invention to provide the directional filter as defined above, wherein said transparent upper and lower electrodes are comprised of resistive material, thereby allowing currents to flow through said resistive material over which a voltage drop will occur, creating electric fields with a controllable degree of tilt. [0074] It is another object of the present invention to provide the directional filter as defined above, wherein said directional filter is additionally provided: a. zero or more additional glass layers, each said additional glass layer being provided with a plurality of transparent, individually addressable electrodes; b. zero or more additional transparent insulating layers, each said transparent insulating layer being disposed adjacent to said glass layer; c. zero or more additional liquid-crystal containing layers disposed between each of said additional transparent insulating layers; and d. zero or more additional polarizing layers, said additional polarizing layers being disposed in front of or behind said additional glass layers, wherein said additional glass, transparent insulating, liquid crystal, and polarizing layers serve to increase and/or decrease the range of direction of incidence for which light intensity is attenuated, and can further serve to block more than one direction of incidence simultaneously, or can further serve to nullify redundant attenuated directions. [0079] It is another object of the present invention to provide the directional filter as defined above, wherein the ratio between the size of said electrodes in their largest dimension to the distance between said upper and lower electrodes is adapted to control the nonlinearities of the electric fields produced by said electrodes. [0080] It is another object of the present invention to provide the directional filter as defined above, wherein said direction-sensitive light detector is selected from a group consisting of: a four-quadrant light sensor, a light detector array of S sensors where S is an integer greater than 0; a low resolution imaging device; a CMOS imaging device; a CCD imaging device; a set of light sensors; an array of photovoltaic cells; and any device with directional and amplitude sensitivity to incident light. [0081] It is another object of the present invention to provide the directional filter as defined above, wherein said control circuitry is adapted to track the light sources of greatest intensity and attenuate the light incident from said light sources by means of orienting the liquid crystals of said middle liquid crystal layer in such a direction as to maximally attenuate the light coming from said sources of greatest intensity, if the intensity of said light sources is above a given intensity threshold. [0082] It is another object of the present invention to provide the directional filter as defined above, adapted to selectively block the light incident upon an optical instrument selected from a group consisting of: camera lens, sunglasses, car windshield visor, motorcycle helmet visor, welding helmet and smart window. [0083] It is another object of the present invention to provide the directional filter as defined above, adapted to selectively block the light incident upon an optical instrument selected from a group consisting of: camera lens, still camera, video camera, sunglasses, vehicle windshield visor, vehicle visor, motorcyclist helmet visor, welding helmet, window, and smart window. [0084] It is another object of the present invention to provide an apparatus for increasing optical dynamic range comprising: a. a front polarizer; b. a front glass plate provided with a plurality of transparent, individually addressable upper electrodes and addressing lines, said front glass plate being disposed behind said front polarizer; c. a front transparent insulating layer, said front transparent insulating layer being disposed behind said front glass plate; d. a middle liquid crystal layer containing liquid crystal molecules, said middle liquid crystal layer being disposed behind said front transparent insulating layer; e. a hind transparent insulating layer, said hind transparent insulating layer being disposed behind said middle liquid crystal layer; f. a hind glass plate provided with a plurality of transparent, individually addressable lower electrodes and addressing lines, hind glass plate being disposed behind said transparent insulating layer; g. a hind polarizer, said hind polarizer being disposed behind said hind glass plate; and, h. control circuitry adapted to provide sequences of voltage patterns to said electrodes of said front glass plate and said hind glass plate, said control circuitry being, adapted to create electric fields at controllable (i) positions, (ii) directions in space; and, (iii) magnitude; wherein said control circuitry is adapted to substantially reduce the transmitted light amplitude coming from the direction of greatest incident radiation, thereby increasing the optical dynamic range of transmitted light. [0094] It is another object of the present invention to provide the directional filter as defined above, wherein said front and back insulating layers are additionally provided with a series of grooves in the directions of said front and back polarizers, respectively. [0095] It is another object of the present invention to provide the directional filter as defined above, wherein the refractive index of the PDLC matrix n p is similar to the ordinary refractive index of the liquid crystal material n o , and wherein both said n p and said n o differ from the extraordinary index of the liquid crystal material n e . [0096] It is another object of the present invention to provide the directional filter as defined above, wherein said voltage sequences are supplied to said upper and lower electrodes so chosen to provide a sequence of electric fields such that the directions of stable equilibrium orientations of said liquid crystal molecules are maintained orthogonal to the direction of required maximal scattering. [0097] It is another object of the present invention to provide the directional filter as defined above, wherein the orientation of said liquid crystal molecules is rotated in time while maintaining orthogonal orientation relative to the direction of required maximal scattering. [0098] It is another object of the present invention to provide a privacy-maintaining window for buildings or other applications comprising: a. a light source disposed outside a window of said building; b. a series of transparent and/or partially mirrored, reflecting surfaces, disposed outside said window of said building; wherein said series of reflecting surfaces act to reflect the light from said light source towards the outside of said building, while allowing light from outside said building to enter said window, thus allowing occupant(s) of said building to see out of said building while preventing those outside from seeing inside said building. [0101] It is another object of the present invention to provide a method for directional filtering of light. The method comprising steps selected inter alia from a. obtaining a front polarizer; b. obtaining a front glass plate having a plurality of transparent, individually addressable upper electrodes and addressing lines; c. disposing said front glass plate behind said front polarizer; d. obtaining a front transparent insulating layer; e. disposing said front transparent insulating layer behind said front glass plate; f. obtaining a middle liquid crystal layer having liquid crystal molecules; g. disposing said middle liquid crystal layer behind said front transparent insulating layer; h. obtaining a hind transparent insulating layer; i. disposing said hind transparent insulating layer behind said middle liquid crystal layer; j. obtaining a hind glass plate provided with a plurality of transparent, individually addressable lower electrodes and addressing lines; k. disposing said hind glass plate behind said transparent insulating layer; l. obtaining a hind polarizer; m. disposing said hind polarizer behind said hind glass plate; and, n. obtaining control circuitry; o. providing sequences of voltage patterns by said control circuitry to said electrodes of said front glass plate and said hind glass plate; thereby creating electric, fields at controllable (i) positions, (ii) directions in space; and, (iii) magnitude; wherein said control circuitry controls the direction of incidence of maximal light absorption for each pixel individually such that the light coming from said direction of incidence is substantially absorbed whilst light coming from other directions is substantially transmitted. [0118] It is another object of the present invention to provide the method as defined above, wherein said front and back insulating layers are, additionally provided with a series of grooves in the directions of said front and back polarizers, respectively. [0119] It is another object of the present invention to provide the method as defined above, wherein said electrodes are composed of indium tin oxide. [0120] It is another object of the present invention to provide the method as defined above, wherein said transparent insulating layers are comprised of polyimide material. [0121] It is another object of the present invention to provide the method as defined above, wherein said individually addressable upper and lower electrodes assume a two-dimensional configuration, allowing for two-dimensional control over said direction of incidence of maximal light absorption. [0122] It is another object of the present invention to provide the method as defined above, wherein said individually addressable upper and lower electrodes are addressed in rows and columns, and wherein electrodes belonging to the same row or column are applied a common voltage, allowing for two-dimensional control over said direction of incidence of maximal light absorption. [0123] It is another object of the present invention to provide the method as defined above, wherein the voltages applied to a subset of said individually addressable upper and lower electrodes is of a magnitude less than that required for complete alignment of liquid crystal molecules' orientations parallel to the applied field, thereby further modifying said direction of incidence of maximal light absorption. [0124] It is another object of the present invention to provide the method as defined above, wherein said electric field magnitude and direction is independently controlled by said control circuitry. [0125] It is another object of the present invention to provide the method as defined above, wherein said electric field magnitude and direction is shared by groups of pixels. [0126] It is another object of the present invention to provide the method as defined above, wherein said groups of pixels are adjacent. [0127] It is another object of the present invention to provide the method as defined above, wherein said groups of pixels occupy arbitrary locations. [0128] It is another object of the present invention to provide the method as defined above, wherein the entire set of said upper electrodes are addressed together, and/or wherein the entire set of said lower electrodes are addressed together. [0129] It is another object of the present invention to provide the method as defined above, wherein said voltage pattern comprises a set of N distinct voltages applied to subsets of said individually addressable upper and lower electrodes, where N is an integer greater than zero. [0130] It is another object of the present invention to provide the method as defined above, wherein said voltage pattern additionally comprises a set of M distinct patterns applied over time, where M is an integer greater than zero. [0131] It is another object of the present invention to provide the method as defined above, wherein said front polarizer is oriented with a polarization direction perpendicular to that of said hind polarizer. [0132] It is another object of the present invention to provide the method as defined above, wherein said front polarizer is oriented with a polarization direction parallel to that of said hind polarizer. [0133] It is another object of the present invention to provide the method as defined above, wherein said front polarizer is oriented with a polarization direction aligned in an arbitrary direction with respect to said hind polarizer. [0134] It is another object of the present invention to provide the method as defined above, wherein said addressing lines on said upper electrodes are oriented perpendicular to the said addressing lines of said lower electrodes. [0135] It is another object of the present invention to provide the method as defined above, wherein said directional filter is additionally provided with a power source selected from a group consisting of: photovoltaic cells, primary voltaic cells, secondary voltaic cells, and one or more adapters facilitating connection to external power sources. [0136] It is another object of the present invention to provide the method as defined above, wherein said directional filter is additionally provided with a direction-sensitive light detector in communication with said control circuitry, said control circuitry being adapted to utilize the direction and intensity information obtained from said direction-sensitive light detector to change said direction of incidence of maximal light absorption. [0137] It is another object of the present invention to provide the method as defined above, wherein the pixels are addressed by a pixel addressing mechanism selected from a group consisting of: passive, active, TFT, or combinations thereof. [0138] It is another object of the present invention to provide the method as defined above, wherein one axis of the electric field pattern is controlled by applying a directional field using a spatial pattern of voltages, while the other axis is controlled by varying the magnitude of applied voltage, thereby achieving two-dimensional control without requiring individual addressing of each pixel in both dimensions. [0139] It is another object of the present invention to provide a method for directional filtering of incoming light. The method comprising step selected inter alia from: a. obtaining a front glass plate provided with a plurality of transparent, individually addressable upper electrodes and addressing lines; b. obtaining a front transparent insulating layer, c. disposing said front transparent insulating layer behind said front glass plate; d. obtaining a middle liquid crystal layer containing droplets of liquid crystal molecules dispersed in a polymer matrix, e. disposing said middle polymer-dispersed liquid crystal layer behind said front transparent insulating layer; f. obtaining a hind transparent insulating layer, g. disposing said hind transparent insulating layer behind said middle liquid crystal layer; h. obtaining a hind glass plate provided with a plurality of transparent, individually addressable lower electrodes and addressing lines, i. disposing said hind glass plate being behind said transparent insulating layer; j. obtaining control circuitry adapted to provide sequences of voltage patterns to said electrodes of said front glass plate and said hind glass plate, said control circuitry being adapted to create electric fields at controllable (i) positions, (ii) directions in space; and, (iii) magnitude; wherein said control circuitry controls the direction of incidence of maximal light scattering for each pixel individually such that the light coming from said direction of incidence is substantially scattered whilst light coming from all other directions is substantially transmitted. It is another object of the present invention to provide the method as defined above, wherein said upper and lower electrodes take the form of parallel, conductive stripes. [0152] It is another object of the present invention to provide the method as defined above, wherein said individually addressable upper and lower electrodes in some of the temporal phases of addressing the electrodes, electrodes belonging to the same row are fed with the same voltage, and in other temporal phases of addressing the electrodes, electrodes belonging to the same column are fed with the same voltage, allowing for two-dimensional control over said direction of incidence of maximal light absorption. [0153] It is another object of the present invention to provide the method as defined above, wherein said sequences of voltage patterns are applied in time periods less than the mechanical time constant of the liquid crystal molecules. [0154] It is another object of the present invention to provide the method as defined above, wherein said polymer-dispersed liquid crystals are rotated in time by means of said voltage patterns applied by said control circuitry. [0155] It is another object of the present invention to provide the method as defined above, wherein said polymer-dispersed liquid crystals are switched in time by means, of said voltage patterns applied by said control circuitry. [0156] It is another object of the present invention to provide the method as defined above, wherein said polymer-dispersed liquid crystals are stationary and directionally controlled by means of said voltage patterns applied by said control circuitry. [0157] It is another object of the present invention to provide the method as defined above, additionally supplied with side electrodes in communication with said control circuitry, wherein said side electrodes can create electric fields parallel to the plane of the layers of the device. [0158] It is another object of the present invention to provide the method as defined above, wherein said transparent upper and lower electrodes are comprised of resistive material, thereby allowing currents to flow through said resistive material over which a voltage drop will occur, creating electric fields with a controllable degree of tilt. [0159] It is another object of the present invention to provide the method as defined above, wherein said method comprising of additional steps of providing with zero or more additional glass layers, each said additional glass layer being provided with a plurality of transparent, individually addressable electrodes; zero or more additional transparent insulating layers, each said transparent insulating layer being disposed adjacent to said glass layer; zero or more additional liquid-crystal containing layers disposed between each of said additional transparent insulating layers; and zero or more additional polarizing layers, said additional polarizing layers being disposed in front of or behind said additional glass layers, wherein said additional glass, transparent insulating, liquid crystal, and polarizing layers serve to increase and/or decrease the range of direction of incidence for which light intensity is attenuated, and can further serve to block more than one direction of incidence simultaneously, or serve to nullify redundant attenuated directions. [0160] It is another object of the present invention to provide the method as defined above, wherein said direction-sensitive light detector is selected from a group consisting of: a four-quadrant light sensor, a light detector array of S sensors where S is an integer greater than 0; a low resolution imaging device; a CMOS imaging device; a CCD imaging device; a set of light sensors; an array of photovoltaic cells; and any device with directional and amplitude sensitivity to incident light. [0161] It is another object of the present invention to provide the method as defined above, wherein said control circuitry is adapted to track the light sources of greatest intensity and attenuate the light incident from said light sources by means of orienting the liquid crystals of said middle liquid crystal layer in such a direction as to maximally attenuate the light coming from said sources of greatest intensity, if the intensity of said light sources is above a given intensity threshold. [0162] It is another object of the present invention to provide the method as defined above, adapted to selectively block the light incident upon an optical instrument selected from a group consisting of: camera lens, sunglasses, car windshield visor, motorcycle helmet visor, welding helmet and smart window. [0163] It is another object of the present invention to provide the method as defined above, adapted to selectively block the light incident upon an optical instrument selected from a group consisting of: camera lens, still camera, video camera, sunglasses, vehicle windshield visor, vehicle visor, motorcyclist helmet visor, welding helmet, window and smart window. [0164] It is another object of the present invention to provide a method for maintain privacy in buildings comprising: a. a light source disposed outside a window of said building; b. a series of reflecting surfaces, transparent and/or partially mirrored, disposed outside said window of said building; wherein said series of reflecting surfaces act to reflect the light from said light source towards the outside of said building, while allowing light from outside said building to enter said window, thus allowing occupant(s) of said building to see out of said building while preventing those outside from seeing inside said building. [0167] It is another object of the present invention to provide a method for increasing optical dynamic range. The method comprising steps selected inter alia from: a. providing a front polarizer; b. providing a front glass plate provided with a plurality of transparent, individually addressable upper electrodes and addressing lines, said front glass plate being disposed behind said front polarizer; c. providing a front transparent insulating layer, said front transparent insulating layer being disposed behind said front glass plate; d. providing a middle liquid crystal layer containing liquid crystal molecules, said middle liquid crystal layer being disposed behind said front transparent insulating layer; e. providing a hind transparent insulating layer, said hind transparent insulating layer being disposed behind said middle liquid crystal layer; f. providing a hind glass plate provided with a plurality of transparent, individually addressable lower, electrodes and addressing lines, said hind glass plate being disposed behind said transparent insulating layer; g. providing a hind polarizer, said hind polarizer being disposed behind said hind glass plate; and, h. providing control circuitry adapted to provide sequences of voltage patterns to said electrodes of said front glass plate and said hind glass plate, said control circuitry being adapted to create electric fields at controllable (i) positions, (ii) directions in space; and, (iii) magnitude; wherein said control circuitry substantially reduces the transmitted light amplitude coming from the direction of greatest incident radiation, thereby increasing the optical dynamic range of transmitted light. [0176] It is another object of the present invention to provide the method as defined above, wherein said light absorbing pigment(s) are dispersed within the volume of said polymer matrix, and/or are dispersed within any material of said directional filter, and/or are dispersed at any boundary between materials of said directional filter. [0177] It is still an object of the present invention to provide the method as defined above, wherein a polarizing polymer (or other polarizing material) is included within said polymer matrix, said polarizing polymer being so oriented to absorb light that has an electric field component normal to the plane defined by said polymer dispersed liquid crystal layer. [0178] It is lastly an object of the present invention to provide the method as defined above, wherein said polymer matrix is made from a polarizing polymer material or other light-polarizing material, and wherein said polarizing material is so oriented as to absorb light that has an electric field component normal to the plane defined by the said polymer dispersed liquid crystal layer. [0179] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0180] The following description is provided, alongside all chapters of the present invention, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, will remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide a directional filter. [0181] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. However, those skilled in, the art will understand that such embodiments may be practiced without these specific details. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment or invention. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Lastly, the terms “comprising”, “including”, “having”, and the like, as used in the present application, are intended to be synonymous. [0182] The term ‘LC’ refers hereinafter to liquid crystal, including birefringent liquid crystals and twisted nematic liquid crystals. [0183] The term ‘smart window’ refers hereinafter to a window or panel that highly absorbs or highly scatters light incident from a selected spatial direction. [0184] The term ‘privacy maintaining window’ refers to a window that allows occupants inside a building to see out but prevents people on the outside from seeing in. [0185] The term ‘LCD’ refers hereinafter to liquid crystal display or to any electro-optic panel based on liquid crystal material. [0186] The term ‘plurality’ refers hereinafter to any integer number equal or higher 1, e.g, 2-10, especially 2-4. [0187] The notation ‘n o ’—refers hereinafter to the ordinary refractive index of the liquid crystal. [0188] The notation ‘n e ’ refers hereinafter to the extraordinary refractive index of the liquid crystal. [0189] The notation ‘n o ’ refers hereinafter to the refractive index of the polymer that functions as the matrix. For this discussion n p is taken to be equal or similar to n o (n p ≈n o ). [0190] The term ‘PDLC’ refers hereinafter to Polymer Dispersed Liquid Crystal. [0191] The term ‘flare effect’ refers hereinafter to non-image forming light that enters an imaging system. Motivation—Applications [0192] The present invention discloses a set of apparatii and associated methods to control the direction from which incident light is maximally absorbed by an electrooptic device. We call this device a directional filter. Before going into the technical details of the invention, we first motivate the discussion by describing a series of uses for such a system of control over the direction of maximum absorption. In a camera, for instance, it is often the case that one particular object in the frame (such as the sun) has a much greater brightness than the surroundings. The brightness of this object will ‘steal’ dynamic range from the surroundings causing them to lose contrast they would have in the absence of the bright object. Thus if the bright object could be darkened without darkening the rest of the field of view, full dynamic range would be restored. It will be noticed that a directional filter as described above can achieve just such an effect. If a directional filter as described above is placed over the lens of an ordinary camera, the direction of maximal incident light absorption can be controlled to attenuate the light transmitted from the direction of the sun. Obviously for this implementation it would be advantageous to have a light sensor included in the device, for determining the direction(s) of maximum brightness. Then the direction of maximum attenuation can be dynamically controlled to follow the brightest object(s) in the field of view as it moves. [0193] Similar applications will be obvious to those skilled in the art. Sunglasses that block the sun but keep the rest of the field of view bright are possible with the directional filter. Vehicle visors that attenuate the sun or the top half of the field of view but keep the rest of the field of view bright are likewise possible. Helmet visors as used in arc-welding are possible which will greatly darken the brightest region where a brilliant arc is present, but leave the rest of the field of view bright and clearly visible (unlike today's helmets, which either blacken most of the scene into obscurity, or else leave a blindingly brilliant region which must be avoided lest one suffer retinal damage). Helmet visors for aircraft or motorcycles can be similarly constructed. Smart windows that attenuate the sun but allow otherwise clear viewing may be constructed for use on houses, or in airplane cabins, or the like. Anti-flare or contrast-enhancing filters can be produced as well. (The ‘flare effect’ in cameras and other imaging system can be avoided. This effect, often appearing as a characteristic polygonal shape with sides dependent on the diaphragm shape, occurs usually near bright objects, when non-image forming light enters the imaging system and is recorded by the image sensor or film. This effect generally lowers overall contrast.) [0194] All of the above devices may be planar or, curved, or may assume any other shape. Method of Operation [0195] Referring to the prior art of FIG. 1 , a twisted nematic LCD comprises six layers. The front polarizer 101 restricts the accepted light to be vertically polarized. Glass layer 102 is provided with transparent electrodes. The polyimide layer 103 underneath it has a ‘brushed’ surface that tends to align the adjacent nematic liquid crystal molecules (which are generally long and thin) of the liquid crystal layer 104 in a particular direction. This direction is chosen to be vertical for the front polyimide layer 103 and horizontal for the back polyimide layer 105 . The crystals in between will try to align themselves to their neighbors resulting in a corkscrew or spiral staircase orientation. The polarization direction of linearly polarized light traveling through such a twisted LC cell follows the rotation of the crystals. Thus in the absence of any further factors (such as an electric field), incoming light will be polarized vertically, travel through the LC cell and thereby become rotated to horizontal polarization, and exit the back polarizer 107 . Schadt and Helfrich discovered an electro-optical effect of a twisted LC layer consisting of positive dielectric nematic molecules under the application of electric fields. They found that the capability of the twisted liquid crystal configuration to rotate the polarization direction of light can be abolished by application of an electric field. Thus the two electrodes 102 , 106 create electric fields in the direction perpendicular to the flat surfaces of the device. These electric fields permeate the nematic liquid crystals in layer 104 . A back polarizer 107 restricts the light passing through this layer to those that are horizontally polarized. The back face 108 may be transparent to allow the light to continue through (in the case of a filter or backlit display) or may be reflective to send the incoming light back to the viewer. Thus in the ‘normal’ state light will pass through the device of FIG. 1 . When an electric field is applied between electrodes 102 , 106 however, light will be blocked causing those, areas under the electrodes of layer 102 to appear dark. [0196] For a pixel that is under a certain magnitude of electric field there exists an angle of incident light which experiences maximal absorption, such that for light rays entering the device at said angle, the outgoing light rays due to these incoming rays have minimal intensity. This effect is modified by the magnitude of applied voltage. Thus for an LCD device, especially if it is supplied with less than the nominal voltage the pixel has maximal absorption and appears darkest for a certain angle of the incoming light. The applied voltage to the pixel can be utilized to assist in controlling this direction of maximal light attenuation. [0197] The preferred embodiment of the present invention consists of controlling the direction of maximum absorption by controlling electric field (direction and magnitude) within the liquid crystal material, preferably in two directions (2 degrees of freedom in direction and one in magnitude). The light absorption will be highest at a direction which is a function of the field's direction, of the field's magnitude, and of parameters of the LCD device. This is in contrast to the operation of today's LC-based devices, which rely on fields perpendicular to the device faces, and which cannot selectively control the directions of light absorption and transmission. [0198] In one embodiment of the invention control over the electric field amplitude and direction is provided independently for each pixel separately. In a second embodiment, control over electric field amplitude and direction is shared by groups of adjacent pixels. In a third embodiment of the invention, control over electric field amplitude and direction is shared by arbitrary groups of pixels. In a fourth embodiment of the invention, control over the electric field amplitude and direction is common to the entire liquid crystal sheet. For all of the above embodiments various spatial locations of the (transparent) electrodes are utilized, and various voltages are applied in a time sequence to said electrodes. [0199] Referring to the prior art of FIG. 2 a a common implementation of LC control is illustrated. The front polarizer 201 is polarized in the upwards vertical direction as indicated by the arrow 212 . The back polarizer 207 is polarized in the direction coming out of the page, as indicated by arrowhead 213 . Liquid crystals are embedded within the liquid crystal chamber 202 , which is provided with front electrodes 203 , 204 for each pixel, and a back plane electrode 6 , common to all pixels. In the normal ‘off’ state of a twisted nematic LC, no voltage is applied between the electrodes 204 , 206 , and therefore no electric field is present in the LC chamber 202 . If no field was desired, the electrodes could both for instance be grounded as indicated by ground symbols 216 , 208 . In this case the LC molecules take the form of a ‘spiral staircase’, whose form is seen in cross section by the ellipses 214 . The ellipses represent the elongated LC molecules, which are oriented in the vertical direction on the side closest to the front vertical polarizer 212 and are oriented in the direction coming out of the page on the side closest to the back ‘out of page’ polarizer 213 . This alignment of the LC molecules is ensured by a series of grooves at the edges of the LC containing layer 202 . The incoming light beam 208 is rotated by the ‘staircase’ orientations of the LC molecules 214 . Therefore incoming light can exit the back polarizer 207 as a ray 209 that has been reduced by only 50% (due to the front polarizer 201 ). [0200] When a ‘high enough’ voltage V 0 is applied to one of the front electrodes 203 by means of voltage V 0 217 an electric field results in the horizontal direction, pointing from the front to back electrode. This is the ‘regular’ direction of the electric field used in LCDs and other LC-based devices. As indicated by the ellipses 215 , the LC molecules (which are somewhat elongated structures) are rotated to align in the direction of the field due to torque arising from an internal dipole moment of the LC molecule being twisted by the external electric field. Because of this alignment, the incoming ray 210 is no longer rotated into the ‘out-of-page’ orientation that would enable it to pass through the back polarizer 207 . Instead, the ray is largely absorbed, and the transmitted beam 211 is relatively weak. Thus far, the operation of this apparatus is of the standard type used in most LCDs. [0201] Next we illustrate the result of using a weakened electric field. A weaker electric field E 1 results from a decreased voltage V 1 that is less than the ‘nominal’ voltage V 0 . The situation is depicted in FIG. 2 b . In this case the LC molecules do not completely rotate into the direction of the field, but rather remain in intermediate orientations as shown by the LC molecules 214 , 215 . The voltages in both top and bottom front electrodes 203 , 204 are kept at V 1 216 , 217 . Now the dependence of transmission amplitude on incidence angle can be shown. For a steep angle of incidence θ 1 in the case of the top ray 208 , the transmission is greatly suppressed, as is shown by outgoing ray 209 . For an incoming ray 210 closer to normal, at angle θ 2 , the transmission is greater as indicated by ray 211 . [0202] Although in general the front and back polarizers are at right angles, they can in principle be used in a parallel configuration. In that case for zero applied voltage the device will block light, while for a high enough applied voltage the device will largely pass light. For purposes of the present invention, in some embodiments the polarization directions of both polarizers may be parallel, perpendicular, or may have other relative angles. [0203] Two of the key modifications of the current invention lie in the use of non-facing electrodes and voltage sequences to create fields at arbitrary angles, not just perpendicular to the device faces. As shown in FIG. 3 , in the main embodiment of the device, the single counter electrode of normal LC devices is replaced by a plurality of back electrodes 305 , 306 . A voltage V 0 316 may now (for example) be applied between top front electrode 304 and bottom back electrode 305 , while bottom front electrode 303 and top back electrodes 306 may be left floating 317 , 318 . If the field strength is large enough the LC molecules 314 will again tend to align in the direction of the applied field which now points from top front electrode 304 to bottom back electrode 305 . An incoming ray 308 at an angle θ 1 depending on that of the LC molecules 314 will be maximally attenuated, with small transmission magnitude 309 . An incoming ray at a different angle of incidence θ 2 however will be less attenuated, as seen by transmission magnitude 311 . [0204] It will now be clear to one skilled in the art that a range of angles may be given to the LC molecules. Referring to FIG. 3 , it will be shown that the LC molecules 314 may be tilted into any angle even though the electrodes 303 - 306 of the example are at fixed positions and hence the angle defined by the lines connecting their midpoints are fixed. One way this may be achieved is by applying a voltage that varies in time. For example, if half the time voltage is applied from bottom front electrode 303 to bottom back electrode 305 (as in FIG. 2 a ), while the other half of the time a voltage is applied between top front electrode 304 and bottom back electrode 305 (as in FIG. 3 ), the direction of the LC molecules will reach an intermediate angle between the horizontal orientation 215 of FIG. 2 a and the large angle of the LC molecules 314 of FIG. 3 . The frequency with which the voltage is alternated may be advantageously chosen to be greater than the relaxation frequency of the LC molecules, such that said molecules do not have time to rotate into the direction of the applied field but are rather trapped in a specific intermediate direction. [0205] To ensure that the entire LC layer 302 attains the same orientation, two-voltage or multi-voltage temporal sequences may be applied to each of the electrodes that results in a specific spatial pattern. Referring to FIG. 4 a - c , we see the sequence of applied voltages and the spatial pattern required to produce a LC orientation parallel to the faces of the LC layer. A series of individual electrodes is used on both top ( 401 - 405 ) and bottom ( 406 - 410 ) of the LC layer. A voltage pattern is applied that repeats after several electrodes. In the example given, there are transparent electrodes centered every 40 μm, specifically an electrode at θ 1 μm (labeled 401 ), an electrode centered at 40 μm (labeled 402 ), an electrode centered at 80 μm (labeled 403 ), an electrode centered at 120 μm (labeled 404 ), an electrode centered at 160 μm (labeled 405 ), etc. The LC layer 411 (the volume occupied by LC molecules) is in some of the embodiments spaced away from the electrodes by a polyimide layer (labeled 412 ) or by other material. All the specific locations, distances, voltages, electric fields, time interval and/or frequencies are given as examples and do not restrict the generality of the disclosed methods. [0206] Referring to FIG. 4 a we see the first voltage pattern applied to the electrodes, called ‘phase A’. In phase A the voltage given to the electrode 401 is 0V, the voltage given to electrode 402 is −40V, the voltage given to electrode 403 is 0V, the voltage given to electrode 404 is +40V, and the pattern repeats with the voltage given to electrode 405 of 0V. The same voltages are applied to the bottom electrodes 406 - 410 . [0207] Referring to FIG. 4 b we see the second voltage pattern applied to the electrodes, called ‘phase B’ which is shifted relative to phase A. In phase B the voltage given to electrode 401 is 40V, the voltage given to electrode 402 is 0V, the voltage given to electrode 403 is −40V, the voltage given to electrode 404 is 0V, and the pattern repeats with the voltage given to electrode 405 of 40V. The same voltages are applied to the bottom electrodes 406 - 410 . [0208] FIGS. 4 a , 4 b show the electric field vectors 413 (small arrows) and equipotential contours 414 (curved lines) resulting from these voltage patterns. Positive equipotential contours are drawn as solid contours, and negative equipotential contours are drawn as dashed contours. It is evident from these electric field patterns that each LC molecule will experience either a field pointing horizontally (parallel to the plane of the panel), or no field. Furthermore any particular molecule will experience only one direction of field; for instance those centered at 0 μm (between electrodes 401 , 406 ) will experience a right-pointing field in phase A ( FIG. 4 a ) and no field in phase B ( FIG. 4 b ), returning to a right-pointing field in the next phase A. Those molecules centered at 40 μm (between electrodes 402 , 407 ) will experience no field in phase A ( FIG. 4 a ) and a right-pointing field (parallel to the plane of the panel) in phase B ( FIG. 4 b ), returning to no field in the next phase A. Similarly those molecules centered at 80 μm (between electrodes 403 , 407 ) will experience a left-pointing field (also parallel to the plane of the panel) in phase A ( FIG. 4 a ) and no field in phase B ( FIG. 4 b ), returning to a left-pointing field in the next phase A. Those molecules centered at 40 μm (between electrodes 402 , 407 ) will experience no field in phase A ( FIG. 4 a ) and a left-pointing field in phase B ( FIG. 4 b ), returning to no field in the next phase A. [0209] Also, for most locations within the LC volume, the stronger the electric field in phase A, the weaker it is in phase B, resulting in relatively uniform time-averaged electric fields magnitudes and directions. [0210] Since applied electric fields exert torques upon the LC molecules unless the molecules are oriented with their long axes parallel to the fields, and since the cycle times for the phase alternations are chosen to be short relative to the LC response time, the LC molecules will reach stable equilibrium orientations that are, for each location, the weighted time-averages of the local applied electric fields. [0211] It should be noted that due to the symmetry of the LC molecule, reversing the electric field will have no effect on the equilibrium orientation of the molecule. Therefore the two phases A,B referred to above can be followed by further phases C,D of opposite polarity from phases A,B. The average value of the electric field at any point is now zero. A zero net field is known to be advantageous for LC applications since there may be ionic components to the LC suspension or the LC molecules themselves which would tend to drift from their original locations in a nonzero DC field. [0212] In FIG. 4 c the stable equilibrium orientations of the LC molecules are illustrated by arrows 415 . The arrows' directions are parallel to the stable equilibrium orientations of the long axes, and the arrows' lengths are proportional to the stability of these orientations (the magnitudes of the returning forces). As one can see in the figure, the stable orientations always lie parallel to the panel's plane (in the horizontal plane). [0213] This sequence of electric field directions is illustrated schematically in FIG. 4 d . In this figure the vertical axis (y-axis) represents the time axis and the x-axis represents the x-direction (horizontal direction) of FIGS. 4 a - c . At 10 ms phase A is applied to the electrodes, causing the LC centered at 0 μm to experience a right-pointing field, those at 40 μm to experience a zero field, those at 80 μm to experience a left-pointing field, etc. At time t=20 ms phase B is applied, with the results pictured. There will be a net average field experienced, and a net average torque tending to align the LC molecules in the direction shown in FIG. 4 c . The opposite voltages are applied in phase C (30 ms) and D (40 ms) with the resulting opposite fields, achieving a zero average field. All references to specific time instances are given as examples and do not restrict the generality of the method. [0214] Further manipulations are now possible due to the independent control over front and back electrodes. An example is given in FIGS. 5 a - 5 c . Here in phase A ( FIG. 5 a ) one applies voltages −40V, 0V, 40V, 0V, −40V etc to top electrodes 501 - 505 . Bottom electrode voltages however are now shifted with respect to the top electrodes, with voltages 0V, −40V, 0V, 40V, 0V etc applied to bottom electrodes 506 - 510 . Phase B is described in FIG. 5 b . As seen in FIGS. 5 a , 5 b the absolute values of the applied electric fields in the LC volume now have a diagonal direction and their average values over the two temporal phases have a relatively uniform magnitude and direction. The weighted time averages of the applied electric fields result in equilibrium orientations of the LC molecules where zero average torques are exerted on them by the applied fields. These equilibrium orientations are plotted in FIG. 5 c where one sees that the resulting orientations have a 45 degree diagonal direction. [0215] Intermediate directions can be obtained by use of more than two phases and/or by varying the amounts of time spent in a given phase relative to the other phases and/or by superposition of several sets of voltage sequences each of which results one predetermined equilibrium direction, and/or by pre-defining sets of voltage sequences each of which results a different LC equilibrium direction, and/or by using any method of interpolation or spanning a vector space using a given basis. [0216] Obviously the ‘standard’ LC direction (normal to the face of the LC layer) can be obtained by applying the same voltage V 1 to all of the top electrodes while, applying a different voltage V 2 to all of the bottom electrodes. [0217] Two dimensional control of the LC directions can be attained (amongst other methods) by using a two-dimensional array of electrodes. Such an array is illustrated in FIG. 6 , which is a top view of a layer of transparent electrodes for use in a LC control system. In analogy to FIGS. 4 and 5 wherein a linear array of electrodes is used, a planar array of electrodes is used in FIG. 6 . The dark (or grey) features outline the conductive features, and the white areas outline the rest of the panel (non-conductive areas). The relatively large rectangles (or pads of any form) make up the pixels, and the narrow paths make up the electric connections between the pixels. This figure shows only a fraction of the layout. The panel (usually) contains many more pixels, so the actual layout extends beyond this fraction of an area (but continues with the same pattern). The conductive pads and features at the edge (or edges) of the panel for making the external connections are not shown since this is known in the art. By varying the spatial pattern of voltages applied in a timed sequence, at a given temporal phase all pads arranged in a the same row can be held to the same voltage while at another temporal phase all pads arranged in a given column can be held to a given voltage. Therefore, the direction of the LC molecules can now be varied in two dimensions, with full control over the azimuthal and horizon angles of the LC molecules (the long axes of the LC molecules can be oriented toward any desired spatial direction). The traces 601 can be continued through the length of the pattern as it repeats multiple times to cover a large area. By means of the 16 independent traces, full two-dimensional control can be attained, as one-dimensional control was attained in FIGS. 4 and 5 with four independent electrodes. A similar pattern to that shown in FIG. 6 would be printed upon both top and bottom glass or polymer surfaces in order to implement the transparent electrodes. As an example, voltages that may be applied to the pads (electrodes) are written on the corners of each pad. The voltages at temporal phase 1 that define effective row-striped electrodes and thus tilts the LC molecules in the y direction are indicated at the upper-left corner of each pad (Ph 1 ,y). A second phase is required for this tilt and the voltages are indicated at the upper-right corner of each pad (Ph 2 ,y). The two phases that define effective column-striped electrodes and thus tilts the LC molecules in the x direction are indicated at the lower-left and lower-right corners of each pad (Ph 1 ,x and Ph 2 ,x). This example should not decrease the generality of our methods as other voltages, other number of phases, other sequences or other values of any parameter may be used. [0218] It is within provision of the invention that the transparent electrode layer (such as the layout that is illustrated in FIG. 6 or other layouts that are herein described) may be separated from the liquid crystal layer by a transparent layer, such as a Polyimide layer or any other polymer layer, or any other transparent layer. [0219] In the example of FIG. 6 the sets of interconnected pixels (pads) located are within a row, or within a column. In this illustration of an example of the layouts of the conductive features, each fourth pixel within a column is interconnected to each other. Therefore, only four edge external connecting pads are required for each column, even if the panel contains hundreds or thousands of pixels in a column. All the pixel's pads that are marked by the same designation (and are located on the same column) are interconnected: all 1A pixels (on the same column) are interconnected, all 2A pixels (on the same column) are interconnected, and so on. [0220] Obviously a different number of traces could be used to provide finer or coarser control of the electric field direction, or alternatively to control smaller or larger sets of pixels at once, or alternatively to control entire areas of the LCD separately. Also, the interconnecting traces that cross from one side of a column of pixels to the other side of the same column of pixels (see FIG. 6 between row # 4 that contains pads 4 A, 4 B, 4 C etc, and the row above it that contains pads 1 A, 1 B, 1 C etc), may be implemented for each column between different rows, instead of all implemented between the same rows of pixels as appear in FIG. 6 . [0221] In some embodiments of the invention, all of the pixel's pads that are marked by the same designation (no matter on which column they are located) are interconnected. In other embodiments of the invention, each column has independent four external (edge) connection pads. In some other implementations of this type, each group of more than one adjacent columns has all the pixel's pads that are marked by the same designation (and that are located within one of the columns in that group) are interconnected (and therefore join the same external edge connection pad). In some other implementations of this type, all the pixels that have the same designations from the entire panel are interconnected, but only for a subset of the designation types that are present on the panel. The interconnected pixels join the same external edge connection pad. [0222] It is emphasized that interconnecting each fourth pixel in a column is only an example. Using the same method, every second pixel in a column or in a row can be interconnected, or every third pixel in a column or in a row can be interconnected, or every fourth pixel in a column, or in a row can be interconnected, or every fifth pixel in a column or in a row can be interconnected, or every sixth pixel in a column or in a row can be interconnected, or every N pixels in a column or in a row can be interconnected, or every other combination of non adjacent pixels in a column, or every other combination of non adjacent pixels in a row, can be interconnected, or every other combination of non adjacent pixels can be interconnected. [0223] It will be clear to one skilled in the art that many different layouts that are topologically (or conceptually) similar to this layout are possible and these are thus claimed within provision of the invention. Generally speaking, the concept of the present invention consists of an array (or tilted array, or alternating array) of pixels (pads) wherein subsets of such pixels, that are not adjacent to each other, are connected within the panel so that a single (or few) external connecting pad can supply this set of pixels with a required voltage. [0224] It is emphasized that the interconnections between the columns that are described here are only examples. Every other mean of interconnection between the columns that is based on layouts that are known in the art is also possible, whether it is based on a single layer of conductive material, on two layers of conductive material, or on any number of layers of conductive material. [0225] Interconnecting similarly-designated columns, using two layers of conductive material (isolated from each other), is also possible. [0226] The rear glass panel may be constructed similar to the first panel, using similar addressing mode of the pixels, or similar features of conductive material. [0227] To attain full control over the LC directions, the addressing of the pixels at the bottom panel must be independent from the addressing of the pixels to the top panel, this being required for the generation of tilted electric fields with controllable direction. [0228] For many of the implementations of panels that are passively addressed (such as the panel described in FIG. 6 , but also for other panels), the features at the opposite panel are placed in 90 degrees rotation relative to the features of the first panel. This will decrease the effect of the ‘dead space’ between electrodes, which will have fields that are generated between the interconnecting paths within the panels. [0229] For minimizing the volume of the liquid crystal that experiences electric fields that emanate from the narrow conducting traces or paths, the traces on each panel should not lay parallel to the traces on the opposite panel. The features of both panels may, in some of the implementations, be rotated by 90 degrees relative to each other. Thereby much of the influence on the liquid crystal by the narrow conducting traces is eliminated. [0230] It is within the core of the present invention that any pixel addressing mechanism known in the art, including passive, active, TFT, or any other pixel addressing method be used independently for front and back electrodes of an LC-containing layer. By this independent control of electric potentials for each individual pixel (or local individual pixel) on both sides of the LC layer, the directions and magnitudes of the applied fields for the individual pixels can be controlled, thus the direction of the LC molecules at each individual pixel and/or the whole panel can be controlled, which has the result that the directions and amplitudes of maximum attenuation or attenuations can be controlled individually for each pixel and/or for the entire panel. Another variation of implementing a pixel related 2D directional field control electrodes: [0231] TFT transistors may be utilized with a sequence of at least 2 temporal phases in a cycle. For the two-phase cycle, in one phase all the pixels that share the same row will be interconnected by the TFT transistors. In the other phase all the pixels that share the same column will be interconnected by the TFT transistors. Thus the electrodes will function like striped-shaped electrodes, but will shift between striped-electrodes in rows and striped-electrodes in columns. In each set of temporal phases electric fields can be generated that can tilt the LC molecules in another plane (there are 2 orthogonal planes that are normal to the LC panel). Therefore the equilibrium orientations of the LC molecules can be controlled as required in all directions. [0232] In another embodiment of the invention, pixels are grouped into sets, and each set of pixels is controlled independently of the other sets. For instance, relatively distant pixels may be connected. This system results in a reduction of the number of required edge connections to the LC layer from external control circuitry. [0233] In a preferred embodiment of the invention, both the magnitude of applied voltage and direction thereof are controlled, thereby combining the effects depicted in FIG. 2 b and FIG. 3 . The magnitude of applied voltage changes the direction of maximum absorption. This effect is taken into account and combined with directional control of FIG. 3 , FIG. 4 and FIG. 5 to control both the direction and magnitude of maximal absorption, blocking angle width and/or absorption level at that angle. The control circuit providing the voltages 316 - 319 can thus control not only the darkness of a given pixel but also the direction from which that pixel appears darkest and range of directions affected. [0234] In another embodiment of the invention, two different methods are used for each axis of a 2-axis control system for the LCD crystals (in e.g. the azimuthal and horizon directions). One axis of control is provided by changing the applied voltage as shown in FIG. 2 b , while the other angle is controlled by the directional field shown in FIG. 3 . [0235] For additional efficiency, electric fields can be simultaneously established at micro-locations of the liquid crystal that are far enough from each other so as not to distort each other's local electric fields. Since the fields generated by each pad affects only LC molecules that are near this and neighboring pads, the voltage that is applied to a given pad can be applied to other, distant pads without generating electric-field interference. This allows pad addressing embodiments such as described in FIG. 6 , which uses a very small number of addressing lines. [0236] The applied electric field that is generated by the electrodes is one of the factors that determine the spatial orientation of the LC molecules. The other factors are the directions of the micro-scratches that are implemented on the (Polyimide) transparent boundaries of the LC layer, inter-molecular forces, stray external electric fields, and other secondary effects. The electric field that is generated by the electrodes at each phase polarizes the Liquid Crystal molecules and effects a rotational moment on the molecules that is a function of the local field orientation, local field strength and the orientation of each Liquid Crystal molecule. In each phase (of the period), the voltages that are applied in that phase generate their own electric fields and rotational moments on the Liquid Crystal (LC) molecules. Since the response time of the LC molecules in terms of changing their orientation can be relatively long (and even longer than the time-period of the applied voltages on the electrodes), each LC molecule can integrate or average all the rotational moments that are executed on it during a period (or a cycle). [0237] A given set of electric fields (one for each phase) that rapidly alternate during each (temporal) period, results in a stable equilibrium orientation for each LC molecule. This means that if the applied voltages on the electrodes were the only factors that generate forces on the LC molecules, and if the temporal period (or cycle) of the alternating phases of these applied voltages were short enough, then each LC molecule averages the rotational moments that affect it in the various phases, and for each LC molecule there is a mechanical equilibrium of its spatial orientation (relative to the electrodes). [0238] The actual equilibrium spatial orientations of the LC molecules may differ from the equilibrium spatial orientations that are calculated only from the applied voltages on the electrodes, because of the other forces on the LC molecules, but nevertheless the actual equilibrium spatial orientations of the LC molecules are a function of the equilibrium spatial orientations that result only from the effect of the applied voltages on the electrodes. [0239] If we designate the direction that is normal to the LC layer as the “normal direction” or the “y direction”, and the direction that is parallel to the LC layer as the “lateral direction” or the “x direction”, then in order to generate a homogeneous LC molecules orientation in the normal direction there is no need of two (or multiple) phases, or all the phases can be identical. [0240] To generate a homogeneous LC molecules orientation in the lateral direction that is maintained in the lateral direction for long distances relative to the electrode widths using relatively low voltages, two or multiple phases of electrode voltage sets are implemented. Each phase creates zones in the LC volume of strong fields and of weak fields, but the phases complement each other so that the resulting equilibrium spatial orientations of the LC molecules due to the effect of the applied voltages on the electrodes is (relatively) homogeneous throughout the LC volume. [0241] In order to implement any required spatial orientation of the LC molecules (within reasonable limits) at least two methods can be implemented: a) For any required spatial orientation of the LC molecules, a unique set of voltages is applied to each electrode in each phase of the period (even the number of phases within a period can depend on the said required spatial orientation). b) A discrete set of predefined spatial orientations may be chosen (for example 0°, 45°, 90°, 135° relative to the lateral direction), for which the voltages on all the electrodes in all the phases of the period that are required to produce each orientation in the LC molecules are known (each set of voltages can be applied also after multiplying all the voltages by a factor). [0244] For any required (arbitrary) spatial orientation of the LC molecules, the two adjoining predefined spatial orientations will be activated alternatively (or simultaneously), with the proper relative weights (by activating each adjoining predefined set for the proper percentage of the time, or by activating each adjoining predefined set with the proper factor to multiply its predefined voltages). For example, if an LC molecules orientation angle of 80° is required, and if the predefined orientations are {0°, 45°, 90°, 135°}, then the two adjoining orientations are 45° and 90°, and either the voltage sets of the 90° are activated for the majority of the time relative to the activation time of the sets of the 45°, or the voltage multiplier of the 90° is larger than the voltage multiplier of the 45°. [0245] In most of the implementations, a 180° rotational symmetry exists in the LC molecules. Therefore equilibrium spatial orientations that differ by 180° are equivalent (for example 0° and 180° are equivalent; 45° and −135° are equivalent; −45° and 135° are equivalent; 90° and −90° are equivalent; etcetera . . . ). Resistive Current-Carrying Electrodes [0246] In another embodiment of the invention, fields with components in the direction parallel to the face of the LC layer are obtained by using resistive, current-carrying electrodes. Since the voltage in such an electrode will drop along its length, the electric fields generated between two such electrodes carefully arranged will have a component in said parallel direction. An example of this embodiment is shown in FIG. 7 . By applying different voltages to the to two ends of a top-side electrode V 1 ,V 2 , and by applying different voltages to the to two ends of a bottom-side electrode V 3 ,V 4 , the electric potentials at each location of each electrode can be controlled, as for each electrode the potential is a linear function or other function determined by the electrode's shape and resistance. The electric field between these electrodes will then take the form indicated by the arrows 703 or other forms that may be tilted relative to the normal to the panel. By varying the voltages involved one may achieve a variety of LC equilibrium angles and hence control the direction of greatest incident light absorption. [0247] By implementing a pair of electrode layers having parallel stripe-shaped configurations on both sides of the LC layer, and by supplying different voltages to the striped-electrodes, in one or two, or several phases in a period, a controlled tilted electric field is produced within the volume of the LC layer. This field will occur in a plane that is normal to the stripes' direction. By connecting each (or a part of) of the striped-electrode to electrical power sources at each of the ends of the stripe, the current that runs through each striped-electrode can be controlled. Because of the finite electrical resistivity of each striped-electrode (that can also be made relatively high), the current through the stripe creates a gradient of electric potential throughout the stripe, and this produces a gradient of electric potentials also in the (nearby located) volume of the LC layer. Therefore, these currents produce an electric field in the volume of the LC beneath the striped-electrode that is directed parallel to the direction of the stripes, in a two-dimensional analog of the situation shown in FIG. 7 . [0248] Another embodiment is as follows. Two electrode layers that contain stripe-shaped electrodes at both sides of the LC are used. All the electrodes (in both layers) are parallel to each other. By applying voltages to the electrodes, electric fields can be generated that can have a controllable direction within a plane that is normal to the direction of the stripes. By mechanically rotating the entire LC panel, including all its layers such as the electrode layers, the plane in which the direction of the electric field can span, can be turned, allowing the system to control the direction of the electric field with two degrees of freedom. [0249] By controlling both the voltages that are supplied to each of the striped-electrodes and the electrical currents that are running through each of the striped-electrodes, electrical fields can be produced in the volume of the LC layer that produce controlled equilibrium directions. [0250] According to a preferred embodiment of the invention, arrays of transparent electrodes are printed or otherwise deposited on glass panels by methods known in the art. In one embodiment of the invention these electrodes are composed of indium-tin-oxide (ITO). A transparent polyimide layer may be placed or printed between the glass/ITO layer and the LC layer. This polyimide layer is then grooved in a given direction to cause the LC molecules to align in the direction of the grooves. These grooves are often created by rubbing the polyimide layer in the desired groove direction. In some of the embodiments of the invention the grooves at the opposite sides may have a relative angle of 90 degrees; in other embodiments the grooves at the opposite sides may have a relative angle of zero degrees or any other number of degrees. In some of the embodiments of the invention there may be no grooves at a given side or at any side. [0251] Practical aspects of the implementation of the invention are now discussed. For a finer control over the electric field direction in the LC layer, two methods may be used: 1. Use of smaller electrodes (where ‘small’ is as compared to e.g. the distance between top and bottom electrodes). 2. Use of a large distance from electrodes to LC layer (where ‘large’ is as compared to e.g. the distance between top and bottom electrodes). 3. Use of electrodes on the side of the glass layer opposite the LC layer. [0255] This large distance may be achieved by use of further glass separation layers or thicker polyimide layers, as will be obvious to one skilled in the art. By way of non-limiting example, consider an LC layer having a thickness of 10 μm (10 micrometer), and transparent electrodes with a width of 30 μm. A reasonable spacing of 30 μm between the electrodes layer and the nearest Polyimide—LC boundary layer (or the nearest LC boundary) is required for achieving reasonable directional control of the electric fields in the LC volume (for the given widths of the electrodes). Such 30 μm spacing may be achieved using a 30 μm thick layer of Polyimide (on each side of the Liquid-Crystal layer). All reference to specific dimensions is only given as an example, and other dimensions may be implemented. [0256] In one embodiment of the invention the ratio between the size of said electrodes in their largest dimension to the distance between said upper and lower electrodes is between about 10 and 0.01. [0257] It is within the scope of the invention that any transparent spacer layer material can be used instead of or in addition to a Polyimide layer. [0258] To block several directions at once, several directional filters as described above may be placed in series, each blocking a particular direction while passing the rest. Alternatively, a single directional filter may be used that simultaneously blocks several directions by dedicating e.g. half of its pixels to blocking a first direction, and using the other half of its pixels to block a second direction. Obviously this method has the drawback that the maximum blocking that can be provided is decreased since the 2 nd direction will be allowed by the 1st pixels and vice versa. Light Detector [0259] Most of the aforementioned devices are preferentially equipped with a direction-sensing light detector to allow automatic open- or closed-loop control over the direction of maximum incident light absorption. This may be accomplished by one of many means known in the art such as an array of light sensors, a four-quadrant light detector, a light detector array that has other number of adjacent sensors, a low resolution imaging device (CMOS imaging device or CCD), an imaging device (CMOS imaging device or CCD), a set of light sensors, an array of 2×2 photovoltaic cells, an array of any number of photovoltaic cells, or any other combination of devices that respond to light and that respond differently for light that is coming from different directions. For antiglare applications that protect cameras, surveillance cameras, still cameras, video cameras or similar devices, the imaging device can be the very imaging device of the camera, and/or a separate imaging device. The devices are further preferentially equipped with controlling circuitry of a suitable type that will be obvious to one skilled in the art (such as a microcontroller, an ASIC controller, FPLD, analog circuit, or any other type of controlling circuitry). The devices are preferentially further equipped with a power source (such as photovoltaic cells that may or may not function also as the light detector array, or primary cell(s), or secondary cell(s), or any other type of electric power), or provided with adaptors to facilitate connection to external power sources. [0260] The direction-sensing light detector determines if a high-intensity light source that radiates light with high enough intensity and with a direction that penetrate the LC panel (and that may reach the protected zone such as the lens or the eyes), is present. The intensity and direction of such glaring light is determined in real-time. Such light may be the sun, or a projector, or headlights, or a welding-arc, or a LASER beam, or any other directional light source. [0261] Control circuitry with input from the light sensor(s) and output to the directional filter determines the intensity and direction of the required electric field to apply to the liquid crystal material within the panels of the glasses, which will result in light absorption that is maximal in the direction of the high-intensity light source. The amount of said absorption is furthermore controlled such that the rays that arrive from the high-intensity light source and penetrate the directional filter are attenuated enough to prevent glare in the transmitted light (which eventually is used by e.g. a camera or a user). In many of the implementations, the operator, the system or the user has control over the magnitude of the maximal attenuation (in several of the implementations the operator, the system or the user may also have control over the direction of maximum absorption). [0262] The preferred location and orientation of the light detector array should be such that it will face approximately in the direction of expected incoming light. For example this would be toward the same direction as the lens faces for camera protection applications, toward the front of the sunglasses (normal to the lenses) for sunglasses applications, or in general oriented such that the center of the filter's light sensing field of view will be similar to the center of the light sensing field of view of the protected camera, system or user. The light detector array can be located at any location that has field of view to the front of the camera, system or sunglasses, or can be the camera's own light detector array. There may be more than one light detector array. The determination of the direction and intensity of the high-intensity light source can be performed in several ways: 1) Imaging device with lens (or lenses, or a mirror, or mirrors, or with a pinhole). The imaging device can be implemented using CCD, CMOS imaging technology, photovoltaic array, or any other imaging technology known in the art. From the location of the focused image of the light source on the surface of the imaging device or the light detector array, the direction of the direct glaring light rays can be inferred. 2) Four-quadrant light detector (or a detector with any other number of light sensing regions), or an imaging device, or photovoltaic array, with a focusing device such as a lens (or lenses, or mirror, or mirrors) that is placed such that light that arrives from sufficiently large field of view at the front of the sunglasses will be converged but not necessarily focused at the light detector's plane. 3) Four-quadrant light detector (or any other number of light sensing regions), or an imaging device, or photovoltaic array, with a hole (or transparent opening) in front of the light detector array. Directional Filter Utilizing Polymer Dispersed Liquid Crystal [0266] Another embodiment of the directional filter involves panels where micro droplets of liquid crystal material(s) are dispersed within a polymer matrix also known as a Polymer Dispersed Liquid Crystal. Our novel approach involves using multiple electrodes at each face of the PDLC sheet (at each side of the plane that is defined by the PDLC), so that by supplying each electrode with voltages that change in time, electric fields are produced in the volume of the PDLC sheet, possibly in several temporal phases. The spatial orientations and magnitudes of the electric fields in each temporal phase are controlled by said applied voltages (which are used to control the orientation of the long axes of the LC molecules, by methods similar to those explained in the previous embodiments not using PDLC). [0267] In each temporal phase the produced electric fields exert forces on the liquid crystal molecules that are in effect mechanical moments that tend to reorient the LC (liquid crystal) molecules along the local lines of electric field. By switching at a fast enough rate between several applied electric fields (with each field exerting a different set of moments on the LC molecules), each LC molecule will assume a spatial orientation in which the mean mechanical moment on itself will nullify. Each LC molecule will be in an equilibrium orientation (that can be described by two orthogonal angles). [0268] All the concepts, methods and implementations that are discussed in this document regarding the generation of electric fields with controlled orientations (and magnitudes) within the volume of a regular liquid crystal sheet, apply also to the generation of electric fields with controlled orientations (and magnitudes) within the volume of a PDLC (Polymer Dispersed Liquid Crystal) sheet, and apply also to the generation of electric fields with controlled orientations (and magnitudes) within the volume of a PSLC (Polymer Stabilized Liquid Crystal) sheet. [0269] The device has a set of transparent electrodes at each side of the PDLC panel that are addressed by various voltages that switch in time, all as described in this document so as to generate controllable electric fields within the volume of the PDLC panel (or sheet) that exert electrical forces on the liquid crystal molecules within the panel that let the orientation of the liquid crystal molecules be stable at a controllable direction (a direction that is defined by two independent spatial angles). [0270] A directional filter using this embodiment, preferentially uses a refractive index of the (usually polymer) matrix n p similar to the ordinary refractive index of the LC material n o , both being different from the LC's extraordinary refractive index n e . When the long axes of the bulk or of all of its LC molecules are oriented toward a specific spatial direction (the “LC direction”), the difference between the refraction indices n p and n e , combined with the highly curved shapes of the LC droplets, will scatter light rays whose direction of incidence is approximately normal to the LC orientation and are polarized parallel to the LC direction. The result is a panel that is relatively transparent in most directions but has relatively hazy, or blurred stripe in the directions normal to the LC direction. We shall define the spatial direction from which direct glaring rays appear, or the spatial direction at which the view needs to be blocked, as the “particular direction”. [0271] In one embodiment of the invention, a PDLC sheet as described in this document and/or as known in the art is provided with sets of transparent electrodes that function as described above. Said electrodes enable the production of electrical fields within the volume of the PDLC sheet with arbitrary controlled spatial orientations and further enable production of the required equilibrium orientations of the liquid crystal molecules within the liquid crystal droplets. [0272] The applied voltages orient the liquid crystal molecules within the liquid crystal droplets; the orientation of the long axes of the LC molecules (the “LC direction”) always maintains 90 degrees angle relative to the “particular direction”. In several implementations the applied electric fields within the volume of the PDLC film are rotated in time so that the LC molecules' orientation also rotates. Each molecule rotates around an axis that passes through the molecule and is oriented parallel to said “particular direction”. [0273] In FIG. 8 an embodiment of the directional filter using a PDLC is illustrated. Transparent electrodes 801 , 802 are used to induce electric fields in the LC layer as in the aforementioned LC embodiments. [0274] See FIG. 9 for an illustration of an example of the normalized light transmission graph, showing transmission 904 as a function of the spatial direction of the incoming light. The graph illustrates the transmission for light rays which are polarized with electrical components that are in planes that contain lines that are parallel to the “LC direction”. In other words, the graph illustrates the transmission for light rays which are not polarized normal to the orientation of the long axes of the LC molecules 903 . The orientation of the long axes of the LC molecules 903 , the “LC direction”, is always maintained normal to the “particular direction” 905 , while said “LC direction” is also rotated in time around an axis parallel to the “particular direction”. Therefore, the panel will appear to a viewer that observes or to a camera that images a scene through the panel as hazy for a rotating stripe that rotates 902 around an axis 905 that connects the viewer with the object at the far side of the “particular direction”, and as progressively more transparent for view angles that are further from the hazy stripe. [0275] Since the said hazy stripe rotates quickly in time (in comparison to the speed of the human visual system), only the “particular direction” will always be obstructed by haziness, but the other directions will be obstructed for only part of the time of the cycle of rotation, and therefore the view to the observer will be clearer and more transparent as the viewing angle is further away from the “particular direction”. [0276] Generally one will employ two mutually orthogonal rotating (or not rotating, or switching) “hazy stripes”. [0277] By implementing two cascading layers (one on top of the other) of PDLC with independent sets of controlling electrodes, so that the incoming light will have to pass both layers in order to pass the whole panel, and by feeding controlling voltages that generate the said hazy stripe in both PDLC layers where the two hazy stripes are mutually orthogonal (and both still rotating in time), all light arriving from the “particular direction” will be scattered (and virtually no light arriving from the “particular direction” will pass the device directly). The view to the observer will be clearer and more transparent as the viewing angle is further away from the “particular direction”. [0278] In this set of implementations, the orientations of both “LC directions” (which are the orientations of the long axes of the LC molecules at the PDLC layer that is far from the viewer and the PDLC layers that is near the viewer), are orthogonal to the “particular direction”. Also, the orientation of the “LC direction” at the PDLC layer that is far from the viewer is orthogonal to the “LC direction” of the PDLC layer that is near the viewer. [0279] In some embodiments of the invention the orientation of the LC molecules is rotated in time. In some implementations the orientation of the LC molecules is not rotated in time. In some implementations of the invention the orientation of the LC molecules is switched in time. [0280] By generating electric fields at the side of the PDLC panel further from the viewer that establish equilibrium orientations of the LC molecules at the further side from the viewer that are orthogonal (normal) to the “particular direction” 905 , and at the same time generating electric fields at the side of the PDLC panel near to viewer that establish equilibrium orientations of the LC molecules at the near side relative to the viewer that are orthogonal (normal) to the “particular direction” but that are also orthogonal (normal) to the orientation of the LC molecules at the further side from the viewer, the view seen by the viewer will be of two orthogonal hazy stripes that cross each other at the “particular direction”. Virtually no light that arrives from the “particular direction”, of any polarity, will pass directly towards the viewer (nor pass in the opposite direction). [0281] The generation of the required fields only at a particular side of the panel is performed using only (or using primarily) the electrodes at the same side. At the same time, the electrodes at the opposite side are used to generate orthogonal fields. [0282] In some embodiments of the invention, the orientations of the LC molecules are also a function of the depth within the PDLC panel. [0283] In some embodiments the invention a light absorbing pigment is dispersed within the volume of the PDLC panel, preferably within the volume of the polymer matrix. This pigment may also be dispersed within any material of the device or at any boundary between materials within the PDLC panel. [0284] In some of the embodiments of this device a polarizer polymer (or other polarizer material) is included within the PDLC panel so that the polarizer absorbs, within the volume of the PDLC panel, light that has an electric field component that is oriented normal to the plane that is defined by the PDLC panel. Only light that travels in a direction tangent (or parallel) to the plane that is defined by the PDLC panel may have this electric field component, although light that travels in a direction tangent to the plane of the PDLC panel may also have an electric field that is oriented tangent to the plane of the PDLC panel. Therefore including such polarizer material within the volume of the PDLC panel will result the absorption one of the two components of the light that travels parallel to the PDLC plane (within the volume of the PDLC panel) but will not affect light that travels normal to the PDLC plane. [0285] Any discussion, description, or drawing in this document regarding controlling the orientations of liquid crystal molecules using electric fields may also find application in implementations that incorporate liquid crystal droplets embedded within a transparent polymer matrix. [0286] Any discussion, description, or drawing in this document regarding a single panel utilizing liquid crystal material(s), with or without it's controlling electrodes, with or without a single or dual polarizers at its faces, with a continuous (regular) or polymer dispersed LC construction, should be regarded also as dual or multi panel construction, in which light rays pass both or all of the panels in series. The LC panels for the dual or multi-panel constructions may be parallel or tilted relative to each other. Privacy Maintaining Windows [0287] Reference is now made to FIG. 10 which illustrates another embodiment of the present invention. In this embodiment of the invention a window is illustrated that allows an occupant of a room to observe the outside scene while blocking the inside scene from the outside world. This is in principle a form of one-way window. The operation is based upon reflection of incoming light from the transparent or partially mirrored surfaces shown in the figure. [0288] The principle is to use reflection of light from transparent or slightly mirrored glass or plastic sheet or sheets 1004 , 1005 . The light source(s) 1001 , 1002 is placed outside the window in places that interfere little with the view through the window. [0289] After being reflected and/or diffused by the fixture 1006 , and/or diffused by sheet 1003 , the light then reaches a clear or partially mirrored sheet or sheets of transparent glass or plastic 1004 , 1005 that are located outside the window (the “reflective sheets”). These are advantageously supplied with couplings 1008 for attachment to the wall 1007 . Some of the light is reflected from the surface (or surfaces) of these sheets in directions away from the house (and away from the window's frame). [0290] The brightness of the reflected light from the “reflective” sheets is much higher than the brightness level of the view of the room from outside the house. This is achieved by using a high enough level of illumination of the external light source and by having enough mirror coating at the reflective sheets. [0291] The reflective sheets produce glare that interferes with the view through the window 1009 , when observing the inside of the room from the outside. However an occupant of the room will be able to see outside easily. This is due to the fact that the light rays that originate from the external light source and that are reflected by the “reflective” sheets, advance only (or mostly) away from the house. The person(s) inside the house can watch the view through the window without being subjected to this glare. [0292] The aforementioned lamp (the “external lamp”) contains some light diffusing element (diffused reflectors, and/or translucent—matt glass or plastic panel, and/or diffused primary light source such as an array of fluorescent tubes). The said external light therefore reaches the “reflective sheets” from many directions and thus reflects towards many external directions.	The present invention provides a multi layer directional filter comprising (a) a front polarizer, (b) a front glass plate provided with a plurality of transparent, individually addressable upper electrodes and addressing lines, said front glass plate being disposed behind said front polarizer, (c) a front transparent insulating layer, said front transparent insulating layer being disposed behind said front glass plate, (d) a middle liquid crystal layer containing liquid crystal molecules, (e) a hind transparent insulating layer, said hind transparent insulating layer being disposed behind said middle liquid crystal layer, (f) a hind glass plate provided with a plurality of transparent, individually addressable lower electrodes and addressing lines, (g) a hind polarizer, said hind polarizer being disposed behind said hind glass plate, and, (h) control circuitry adapted to provide sequences of voltage patterns to said electrodes of said front glass plate and said hind glass plate.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATION This application claims priority of German Application No. 198 52 977.5 filed Nov. 17, 1998, the disclosure of which is incorporated fully herein by reference. FIELD OF THE INVENTION The invention relates to a device for providing relative motion between two components of a cable window lifter that lie in the force transfer cord and are positioned prestressed to one another. The device functions as a dampener and/or for ensuring the provision of sensor signals for clamping protection, in particular when severe clamping leads to a sudden and complete standstill of the window pane. BACKGROUND OF THE INVENTION DE 196 18 853 C1 disclosed a motor-driven window lifter with electronic clamping protection, whereby in the flux of force between the drive unit and the window pane there is a prestressed spring with a degressive course. When the prestress force is exceeded, this leads to relative motion of the components that are tensioned to one another, whereby the total stress of the spring is reduced and the clamping force is correspondingly reduced. It is provided that the spring is positioned within an essentially rigid case. The case, which for the purpose of supporting the great prestress force is formed in a comparatively stable way, has a high space requirement that is often not available. In addition, the assembly of the device described requires relatively high resources. The contents of DE 198 52 977.5 are incorporated fully herein by reference. SUMMARY OF THE INVENTION It is an object of the present invention to develop a type of device that is characterised by a reduced space requirement, simple assembly, and a small number of components. In addition, with the use of as little material as possible, high stability and operating reliability should nonetheless be ensured. When clippable connecting components are provided for connecting the two tensioned and displaceable components a conflict is solved whereby on the one hand the clippable connecting components should be formed as flexibly as possible for a simple connection process and on the other hand, the clippable connecting components should be formed as rigidly as possible for ensuring high stability of the connection. According to an embodiment of the present invention, after complete installation of the device, the connection between the friction locking components is ensured against unintended loosening. This occurs preferably through a functional component of this device, thus through one of the components that can be displaced relative to the other, or through the prestressed spring itself, which brings about the pressing apart of the friction locking components. According to an embodiment of the present invention, after assembly of the device, the friction locking components are at least partly surrounded and supported by the spring in such a way as to prevent a bending open of an elastically deforming or radially displaceable friction locking component. The corresponding friction locking component must therefore simply take up the pulling forces arising through the prestress. Radially oriented forces, such as bending forces, are taken up by the spring. Ideally, the clippable friction locking components of the two axially displaceable components lie completely between the end-side supports of the spring in such a way that the spring encompasses the friction locking components completely. In adapting to the construction and assembly concept of the window lifter, the device according to an embodiment of the present invention can be formed either as a pre-manufactured unit that can be assembled separately, or as an integral component of the drive unit. For a pre-manufactured unit it would be necessary to provide a bearing opening in a casing component of the drive unit, so that one of the displaceable components of the device can be inserted and supported against a stop. Alternatively, the friction locking components are a constituent part of a casing component and extend along the cable axis. The friction locking components of the other component are preferably a constituent part of a generally used guiding shell, which through the interposition of a cable length compensation spring supports the end of a Bowden tube. They can, however, also be a constituent part of an adapter that is positioned between the other component carrying friction locking components and the guiding shell. This enables the device according to the invention to be easily inserted into series which are already running by merely shortening the length of a Bowden tube. All other components can be taken over without any changes. Through the securing of the engaging friction locking components of the components that can be displaced relative to one another and are tensioned with one another, the conditions are created whereby clippable connections can be used as friction locking components. This is a basis for solving the conflict that arises because in order to produce a simple connection between two components, elastically deforming friction locking components should be sought, but the tensioning of these components through a comparatively high spring force requires a solid formation of the connection points. According to the invention, the conflicting demands are met because, at least one component of the device that functions to ensure relative motion after assembly additionally assumes a securing function for the permanent engaging of the friction locking components. The invention can be brought into effect in embodiments which vary greatly in their construction. Depending upon these different embodiments, for example, either one or both of the clippable areas participating in the connection of the displaceable components should be elastically formed. When both of the clippable areas are elastically formed, the relative degree of deformation of the clippable areas can be kept comparatively lower. In certain circumstances, however, securing measures for both clippable areas are necessary, which guarantee permanent friction locking. The clippable area that springs inwards can be secured via an axial channel, into which the securing component is inserted, e.g. in the form of a guiding shell supporting the Bowden. When only one clippable area is elastically formed, the clippable area of one component is formed essentially rigidly, whereas the other clippable area must have the entire flexibility necessary for the production of friction locking. The invention is also intended to include a device with a separate securing component, that can be used in association with the generally used guiding shells for cable length compensation of a Bowden tube window lifter. Special stops formed contrary to the assembly direction are intended to guarantee security against the loss of the separate securing component during transport of the device up until its assembly. According to an additional embodiment of the invention, shell-like components or other components that can be placed radially are used, whereby these components form one of the two displaceable components and support the prestressed spring on one side. The securing of the functional position of these components takes place through friction locking with the end of the spring. BRIEF DESCRIPTION OF THE DRAWINGS The invention is described below by reference to embodiments of the invention and the figures illustrated, wherein: FIG. 1 a is a side view of a device with outer clippable areas and a prestressed spring as the securing component. FIG. 1 b is a transverse section of FIG. 1 a. FIG. 1 c is a perspective diagram of FIG. 1 a. FIG. 1 d is the same as FIG. 1 c, but without springs. FIG. 1 e is a perspective diagram of the relatively displaceable component on the casing side. FIG. 2 is a transverse section of a device with a securing component completely encompassing the elastic clippable area. FIG. 3 is a transverse section of a device with guiding channels in both displaceable components. FIG. 4 a is a side view of a device with outer and inner clippable fields as well as outer and inner securing components. FIG. 4 b is a transverse section of FIG. 4 a. FIG. 4 c is a perspective diagram of FIG. 4 a. FIG. 4 d is the same as FIG. 4 c, but without a spring. FIG. 5 a is a side view of a device with relatively displaceable components which are not tensioned. FIG. 5 b is a transverse section of FIG. 5 a, rotated by 90°. FIG. 5 c is a transverse section of FIG. 5 a (Section B—B). FIG. 5 d is a perspective diagram of FIG. 5 a. FIG. 5 e is a perspective “exploded” diagram of the two displaceable components. FIG. 5 f is a cross-section through the device of FIG. 5 a (Section C—C). FIG. 5 g is a plan view of the device. FIG. 5 h is a perspective “exploded” diagram of the device of FIG. 5 a. FIG. 6 a is a partially sectional side view of a device with a flexible, clippable area that is in pipe form. FIG. 6 b is a transverse section of FIG. 6 a. FIG. 6 c is a transverse section of FIG. 6 a, rotated by 90° with the spring removed. FIG. 6 d is a perspective diagram of FIG. 6 a. FIG. 6 e is a perspective exploded diagram of the relatively displaceable components. FIG. 7 a is a side view of a device wherein one of the two relatively displaceable components is radially positionable. FIG. 7 b is a transverse section of FIG. 7 a, rotated by 90°. FIG. 7 c is a perspective diagram of FIG. 7 a. FIG. 7 d is the same as FIG. 7 c, but without a spring. FIG. 8 a is a side view of a device one of the two relatively displaceable components is double-shell-formed and radially erectable. FIG. 8 b is a transverse section of FIG. 8 a, rotated by 90°. FIG. 8 c is a perspective diagram of FIG. 8 a. FIG. 8 d is the same as FIG. 8 c, but without a spring. FIG. 9 is a dual cable Bowden tube window lifter with an electric drive and a device according to an embodiment of the present invention which is inserted into a cable exit of the drive case. DETAILED DESCRIPTION FIGS. 1 a to 1 e show a device according to an embodiment of the present invention from different perspectives, whereby rigid inner friction locking components of one component 2 a in the form of a ring-form projection 24 a engage with flexible, clippable friction locking components 11 a of the other component 1 a. The hook-like friction locking components 11 a of the component 1 a form the free end of the area 10 a, which is divided into elastic segments through axially running slits 100 a (only shown in FIG. 1 e ). At the other end, the component 1 a merges into a pipe-formed guiding area 14 a with a reduced diameter, whereby on the inner side this guiding area 14 a takes up the guiding tube 25 a of the component 2 a, and whereby on the outside it carries a spring 4 supported on the casing side to compensate for the cable length. The upper end of the component 2 a is formed as a supporting area 20 a for a Bowden tube which is inserted into a tube-like opening 22 a and supports itself with its end on the stop 23 a. For the purpose of supporting the spring 3 , the outer contour of the supporting area 20 a is formed as a ring-form projection 21 a. The other side of the spring 3 is supported on the ring-form projection 12 a of the component 1 a, whereby the spring 3 overlaps the area of the friction locking components 11 a, 24 a, and thus ensures a secure positioning of the elastic fields 10 a, even when there is very great axial tension. The prestress force of the spring 3 is generally selected to correspond at least to the sum of the mass force of the window pane and all the forces that are effective up to the device. Therefore, via the lift of the window pane until arrival at the sealing area on the end position side, there is no compressing of the spring 3 . As soon as the supporting force exerted by the Bowden tube on the component 2 a exceeds the prestress force of the spring 3 , the latter is compressed and the component 2 a is displaced in the component 1 a. This displacement is limited by a stop 13 a, which forms the passage between the areas 10 a and 14 a. In any case, however, the possible relative motion between the components 1 a and 2 a is dimensioned to be sufficiently large to ensure that, in the event of a blocking of the displacement movement of the window pane, the drive can still generate the signals necessary for the recognition of the blocking. In the case of a severe, i.e. sudden, blocking, an additional sensor signal must as a rule be fed to the evaluation electronics. The conditions are fulfilled when the relative motion between the two components 1 a, 2 a is sufficient for the generation of a signal period. It is thereby ensured that after the beginning of the clamping at least one further signal is generated. In comparison with the above-described embodiment, the device according to an alternative embodiment shown in FIG. 2 differs essentially through an axially displaced positioning of the rigid friction locking component 24 b of the component 2 b and of the ring-form projection 12 b of the component 1 b. Through the positioning of the ring-form projection 12 b in the area of the stop 13 b, the spring 3 overlaps the entire elastically deforming area 10 b and thus ensures friction locking between the friction locking components 11 b and 24 b. Note that in FIG. 2 and all other figures, items denoted by a number immediately followed by a subscript letter correspond generally to similarly numbered items with different subscript letters that are appearing in separately numbered figures showing alternate embodiments of the invention. FIG. 3 shows an additional embodiment that is very similar to the device shown in FIG. 1 . The device shown in FIG. 3 differs in that the guiding tube 25 c which is connected to the Bowden supporting area 20 c does not extend through the component 1 c, but instead ends in the guiding area 14 c. Instead, a further guiding tube 15 c connects to the guiding area 14 c, so that the cable is fed through two separate channels that are positioned axially behind one another. The embodiment shown in FIGS. 4 a to 4 d has displaceable components 1 d, 2 d, whereby there are friction locking components 11 d, 23 d which are worked onto the spring elastic fields 10 d, 22 d. To prevent the friction locking components 11 d of the component 1 d on the casing side from moving away inwards, a guiding shell 55 d is inserted into a corresponding central channel. The guiding shell is also shown with a bottom 53 d and a ledge 54 d between the supporting area and the channel. The position of the friction locking component 23 d of the component 2 d on the Bowden side is, as in all the previously described examples, ensured by the encompassing of the spring 3 . In order to ensure cable length compensation, a spring 4 is provided, that supports itself on the one hand on the ring-form projection 51 d of the supporting area 50 d and on the other hand on an inwardly oriented projection 20 d of the component 2 d, which also serves as a stop for limiting the relative motion between the components 1 d, 2 d. An advantage of this embodiment is the possibility of further use of guiding shells 5 d commonly in use and the simple rearrangement of devices that are already positioned in series without a tensioned spring 3 . FIGS. 5 a to 5 h show a device whereby the prestressed spring 3 supports itself between a ring-form projection 12 e and a hook-like friction locking component 11 e of the component 1 e on the casing side that is positioned on the free end of the elastic area 10 e. The Bowden side component 2 e can be inserted between the spring sides (areas 10 e ) and into the axial channel 16 e attached thereto, whereby this Bowden side component 2 e works against an inward evasion of the friction locking components 11 e. The spring side 10 e has in the vicinity of the friction locking component 11 e a ledge forming a stop 15 e, which—in association with the ledge of the inserted component 2 e forming a stop 25 e —forms security against loss. The component 2 e also has an axial channel 27 e, in which the guiding tube 55 e of the guiding shell 5 e is fed. The supporting field 50 e, which takes the Bowden tube end, has on its outer contour a spring 4 for cable length compensation, whereby this spring 4 supports itself on the one hand on the ring-form projection 51 e and on the other hand on the axial stop 24 e of the upper end of the displaceable component 2 e. In the event of cable lengthening, the spring 4 would push the guiding shell 5 e out of the channel 27 e of the component 2 by the corresponding length. As can be clearly seen from the FIGS. 5 b and 5 c as well as the FIGS. 5 e and 5 h, the displaceable components 1 e and 2 e are not formed rotation-symmetrically. Instead they have opposite-lying, differing sectors with differing functions. Thus, the sector 20 e of the component 2 e is not only equipped with a stop 24 e for the cable length compensating spring 4 , but is also equipped with a projection 21 e, which transfers the supporting force of the Bowden tube on to the allocated end of the prestressed spring 3 , and upon the prestress force being exceeded compresses the spring 3 , whereby this goes hand in hand with relative motion between the two components 1 e, 2 e and a lifting of this spring end from the stops 11 e. The component 1 e also has a base 10 ′ e. On the other side of the projection 21 e the sector 20 e has a continuation, which functions in a stop 23 e in association with the stop 13 e of the component 1 e for the purpose of limiting the relative motion. The stopper 22 e attaching thereto serves for the guiding of the component 2 e in the channel 16 e of the component 1 e. The area 26 ′ e extending over the stopper 22 e into the vicinity of the projection 21 e serves for guiding the spring sides 10 e and continues via a ledge 25 e in the surface 26 e. As already mentioned, the combination of the ledges 25 e with the ledges 15 e on the inner sides of the spring sides 10 e gives rise to a security against loss, whereby this is intended to prevent the Bowden side component 2 e slipping unintentionally out of the component 1 e on the casing side. FIGS. 6 a to 6 e show an additional embodiment of the invention. This embodiment uses a component 1 f on the casing side, which on the one hand can be connected via the coupling area 14 f to a case (not illustrated), and which on the other hand has an elastically deforming area 10 f with an essentially cylinder-casing-like contour. The area 10 f is provided with recesses 11 ′ f which are limited by the projection 12 f provided for supporting the spring 3 and by a closed ring 11 f, whereby the inner surface of the ring 11 f limiting the recess 11 ′ f functions as a friction locking component for engaging the friction locking component 23 f of the component 2 f on the Bowden side. The friction locking component 23 f is formed as a hook-like projection on the stopper 22 f. Before the connection of the two components 1 f and 2 f, the spring 3 must be pushed away from the areas of the friction locking components 11 f, 23 f, in order to allow the elastic deformations necessary for the connection. Upon insertion of the component 2 f into the component 1 f, first the ring 11 f is elastically deformed through the friction locking components 23 f until the friction locking components 23 f engage in the recess. The spring 3 can subsequently be released, whereby the spring 3 now supports itself between the projections 12 f and 21 f and encloses the area of the friction locking components 11 f and 23 f in such a narrow way that the degree of deformation of the friction locking components 11 f, 23 f necessary for the uncoupling is excluded through the spring 3 . A limitation of the spring excursion between the components 1 f and 2 f is given by the axial length of the recess 11 ′ f in that the edge of the recess 11 ′ f serves as a stop for the friction locking component 23 f. All of the above-described devices have displaceable components 1 , 2 that are positioned to one another through an axial assembly movement. This does not apply to the embodiments of the invention of FIGS. 7 and 8, which are explained below. In the embodiments shown in FIGS. 7 and 8, the assembly movement of the component 1 g, 1 h on the casing side takes place radially to the longitudinal axis of the component 2 g, 2 h on the Bowden side. FIGS. 7 a to 7 d show a component 1 g on the casing side with a cut-away portion 18 g, which is intended to facilitate a radial positioning on the other component 2 g. The component 1 g has a radially inward area, whereby this area, upon completion of the assembly, engages a cut-away portion 28 g of the component 2 g and can engage with a projection of the component 2 g functioning as a stop 24 g. Between the projections 12 g and 21 g, the prestressed spring is supported. A permanent and secure positioning of the two components 1 g and 2 g in relation to one another can be ensured by an axially directed arching 11 g over the projection 12 g on the side lying opposite the cut-away portion, and by an expansion of the supporting area 20 g of the component 2 g corresponding approximately to the inner diameter of the spring 3 . If the prestress force of the spring 3 is exceeded by the supporting force of the Bowden tube inserted into the opening 22 g, the component 2 g is depressed, whereby the stop 11 g displaces itself within the cut-away portion 28 g. The maximum possible relative motion is again determined through the internal width of the cut-away portion after the assembly of the component 1 g. The embodiment shown in FIG. 8 corresponds essentially to that of FIG. 1, but with the difference that the component 1 h consists of two half shells divided by slits 16 h, whereby these half shells are connected to each other by means of a film joint 15 h. FIG. 9 shows a dual cable Bowden tube window lifter with two guiding passages 8 a, 8 b on which grippers 9 a, 9 b are positioned in a sliding way for the purpose of connection of the window pane. The driving force is transferred from a drive unit 7 consisting of a motor 71 and drive 70 via the cable loop to the grippers 9 a, 9 b. The cable is thereby guided trough Bowden tubes 6 and over upper and lower cable deflections 80 , 81 . A device according to the embodiment shown in FIG. 5 is connected to one of the cable exits of the drive 70 .	The invention relates to a device for providing relative motion between two components of a cable window lifter which lie in the force transfer cord and are prestressed to one another, and functions as a dampener and for ensuring the provision of sensor signals for clamping protection, particularly if severe clamping leads to a sudden and complete standstill of the window pane. The device consists of a component on the casing side and a component positioned directly or indirectly thereto, on which the Bowden of a cable window lifter supports itself, whereby the two displaceable components that are connected to one another through friction locking components are pressed against reciprocally allocated stops by means of a prestressed spring. After completion of the assembly—the connection of the friction locking components is ensured against unintentional loosening through the prestressed spring or one of the components that can be displaced relative to another.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION The present invention relates generally to a gate, particularly to a safety gate for the inside of a residence, and specifically to such a safety gate that requires two steps to open. BACKGROUND OF THE INVENTION Children have boundless curiosity. Children can figure out how things work without books. For example, given time, a child can figure out how a gate works so that he or she can get to the other side or so that the dog can be let in. However, a child, especially a toddler, lacks physical strength. Adults and teenagers are too busy and have little time. While a dog may move out of the master's path, a gate does not. A gate must be dealt with. If a gate is difficult to manage, then the gate will be removed or left open. If a gate is made easy to open and easy to close, then the chances are maximized that the adult or teenager will keep the gate closed to keep the children safe from falling down the stairs or to keep the dog in or out. SUMMARY OF THE INVENTION A feature of the present invention is a two-action gate that requires two steps to open. One step is a sliding of a latch with the thumb and the second step is a lifting of the gate with the remainder of the hand to free up a double stop while the latch is retained in an open position with the thumb. Thus, only one hand is required to manage the gate to make the gate easy to open and easy to close. Another feature of the present invention is the weight of the gate. The gate is preferably relatively heavy from the standpoint of a toddler. A toddler may be able to manage the sliding of the latch. However, a toddler may not be able to manage to lift the gate so as to free up the double stop. The chances are fewer yet that the toddler can keep the latch open with one hand and lift the gate with the other hand. The material of the gate is preferably metal such as stainless steel. Another feature of the present invention is that one control mechanism, the latch, for keeping the gate closed is positioned at an upper portion of the gate, and that another feature of the invention, the double stop, for keeping the gate closed is positioned at a lower portion of the gate such that the gate includes a two point connection when closed. When closed and pushed against, the gate remains square in its frame without any swaying or twisting. An advantage of the present invention is that chances are maximized that a toddler cannot open the gate. The two-action or the two steps in combination provide difficulty for the child. Another advantage of the present invention is that chances are maximized that older people in the household, such as adults and teenagers, will keep the gate closed. The two-action or two steps in combination are easily managed with one hand by a teenager or adult. Another advantage of the present invention is that the gate is simple and inexpensive to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the present two-action gate in a closed position. FIG. 2 is a side, detail view of the two-action gate of FIG. 1 and demonstrates how the latch is managed by the thumb and how the remainder of the hand may grasp the gate to lift the gate. FIG. 3 is a side, detail, partial section view of the latch of FIG. 2 and shows the latch in a closed position. FIG. 4 is a side, detail, partial section view of the latch of FIG. 2 , shows the latch in an open position, and further shows how the gate is lifted while the latch is in the open position. FIG. 5 is a side, detail view of the gate of FIG. 1 and shows the lower pivot connection of the gate. FIG. 6 is a side, detail view of the gate of FIG. 1 and shows the double stop engaged to the frame. FIG. 7 is a section view of the double stop of FIG. 6 at lines 7 - 7 of FIG. 6 and shows the double stop engaged to the frame in solid lines and clear of the frame in phantom lines. FIG. 8 is a side, detail view of the gate of FIG. 1 and shows the upper pivot connection of the gate. DESCRIPTION As shown in FIG. 1 , the present gate apparatus is indicated in general by the reference number 10 . Gate apparatus 10 includes a frame or outer frame 12 , a gate 14 , a latch mechanism 16 , and a double stop 18 . Outer frame 12 generally includes a first side portion 20 , a second side portion 22 and a lower portion 24 . More specifically, each of the side portions 20 , 22 of the outer frame 12 includes an upper structural member 26 that extends generally horizontally, a lower structural member or member portion 28 that extends generally horizontally, an outer or first structural member 30 that extends generally vertically and is engaged, such as by welding, to and between the members 26 and 28 , and an inner or second structural member 32 that extends generally vertically and is engaged, such as by welding, to and between the members 26 and 28 . Outer frame 12 further includes, as part of the side section 22 , an inner structural member 33 that extends generally vertically to and between the upper member 26 of side section 22 and lower member 28 . Inner member 33 is referred to as the axis of the gate 14 . Gate 14 is journaled upon inner member 33 . Inner member 33 is fixed to lower member 28 via a pin and extends into upper member 26 via an opening in which inner member 33 frictionally fits. Outer frame 12 is a compression frame. Outer frame 12 and gate 14 are disposed generally in a plane. Each of the side portions 20 and 22 includes an upper portion that includes the horizontally extending member 26 . The upper portions, including members 26 , are relatively drawable to and away from each other in such plane and such upper portions are biased away from each other such that, when the upper portions are drawn together, the outer frame 12 is compressed. This compression is maintained when male members 34 are engaged in female members in an exterior frame or apparatus, where such exterior frame or apparatus is part of a partition or barrier or where such exterior frame or apparatus extends from opposing walls or opposing portions of a door frame. Upper male members 34 extend from and are integral and one-piece with upper member 26 . Lower male members 34 extend from and are one-piece with lower member 28 . To provide such a compression, one or more of the side portions 20 , 22 may be manufactured so as to be slightly oblique relative to the lower portion 24 of the outer frame 12 . It should be noted that the four male members or four points of connection 34 may alternatively be female members, or the four points of connection may include a combination of male and female members. Members 26 and 28 run generally parallel to each other when the outer frame 12 is compressed. Side portions 20 and 22 run generally parallel to each other when the outer frame 12 is compressed. Members 20 and 32 run generally parallel to each other when the frame is compressed or in an uncompressed state. Upper horizontally extending member 26 is a cylindrical tube. Lower horizontally extending member 28 is tubular and in vertical section takes the form of a rectangle. Outer or first vertical member 30 can be a tube or a rod. Inner or second vertical member 32 is a tube. Inner member or axis 33 can be a tube or rod. Outer frame 12 , including members 26 , 28 , 30 , 32 and 33 , is preferably formed of a metal. Of the metals, stainless steel is preferred. If desired, aluminum may be used. Gate 14 includes its own frame 36 . Gate frame 36 includes an upper structural member 38 extending generally horizontally, a lower structural member 40 extending generally horizontally, a first end vertical structural member 42 extending generally vertically and engaged between the upper and lower members 38 and 40 , and a second end vertical structural member 44 extending generally vertically and engaged between the upper and lower members 38 and 40 . Member 44 is journaled upon axis member 33 such that gate 14 can swing about the axis member 33 . Member 44 is also axially slidable in the vertical direction along axis member 33 such that the gate 14 can be lifted up and set down in a vertical fashion. Gate frame 36 further includes a pair of inner vertical structural members 46 extending generally vertically and engaged between the upper and lower members 38 and 40 . Between the inner vertical structural members 46 is engaged a relatively short member 48 extending generally horizontally. Between the short member 48 and the upper member 36 is engaged two relatively short inner members 50 extending generally vertically. Pivotally engaged within short member 48 , lower member 40 and side members 46 is a relatively small gate 52 having four vertically extending structural members and two horizontally extending structural members. Small gate 52 includes a spring biased latch 54 that cooperates with one side member 46 and is biased to the closed position. Small gate 52 is pivotally engaged via pin connectors to members 40 , 48 at the end of the gate 52 that is opposite latch 54 . Small gate 52 can swing out to either side of gate 14 . Gate frame 36 , including structural members 38 , 40 , 42 , 44 , 46 , 48 , and 50 and further including small gate 52 and the structural members of the small gate 52 , is preferably tubular. If desired, one or more of such structural members may be rods. Gate frame 36 , including such structural members, is preferably formed of a metal. One preferred metal is stainless steel. If desired, aluminum may be used. Gate frame 36 is preferably relatively heavy for a toddler to lift vertically and relatively light for the teenager or adult to lift vertically. FIGS. 5 and 8 show a swinging and lifting arrangement between the gate 14 and the outer frame 12 . As shown in FIG. 5 , member 33 is engaged to member 44 via a lower slippery collar 56 that permits both of a smooth swinging and lifting of gate 14 relative to member 33 . Collar 56 is inset into a lower open end of member 44 . As shown in FIG. 8 , an upper slippery collar 58 is inset in an upper open end of member 44 to journal member 33 within member 44 . Like with lower collar 56 , such permits both of a smooth swinging and lifting of gate 14 relative to member 33 . As further shown in FIG. 8 , member 44 is engaged to upper member 38 of gate 14 via an angle bracket 60 . Such a construction defines the upper limit to a vertical travel of the gate 14 relative to the frame 12 . In other words, when the gate 14 is lifted, upper collar 58 , preferably formed of a plastic material, abuts the undersurface of member 26 such that the upper collar 58 and undersurface act as stops relative to each other. A lower limit to the vertical travel of the gate 14 relative to the frame 12 is provided by a portion of the latch mechanism 16 . The latch mechanism 16 is shown in FIGS. 2 , 3 and 4 . Latch mechanism 16 includes a generally U-shaped slide 62 slideably mounted on member 38 of gate 14 . Slide 62 includes a thumb tab 64 extending from a rear end of the slide 62 . Thumb tab 64 may be slid back by the thumb when the remaining portion of the hand, namely the fingers and/or palm of the hand, grab upper member 38 to lift the gate 14 . Slide 62 is fixedly engaged with a pin connector 66 to a latch piece 67 that slides in member 38 . Axially extending slots formed in both sides of member 38 receive the pin connector 66 and define how far the slide 62 and latch piece 67 can slide rearwardly, i.e., in the direction of axis member 33 . An end 68 of a structural member extension 70 defines how far the slide 62 and latch piece 67 can slide forwardly, i.e., away from axis member 33 . Structural member extension 70 is cylindrical and formed in the shape of a half-pipe such that extension 70 has an upper portion and a pair of side sections. Extension 70 is fixedly engaged to an upper half portion of member 38 and extends in the axial direction to bridge a gap over to member 26 , the upper half-exterior of which forms a cylindrical seat 71 for seating extension 70 . Extension 70 and seat 71 define the lower limit for the vertical travel of gate 14 when gate 14 is set down so as to engage the double stop 18 upon member 28 and, again, as shown in FIG. 8 , collar 58 and the undersurface of member 26 of section 22 define the upper limit for the vertical travel of gate 14 relative to frame 12 . When seated on seat 71 , extension 70 maintains lower member 40 in a spaced apart and generally parallel relationship to member 28 . When gate 14 is set down to one side of the frame 12 or to the other side of frame 12 such that the double stop 18 is not engaged, then the plastic lower collar 56 rides upon the upper surface of member 28 such the gate 14 swings easily on either of the sides of the frame 12 and such that the upper surface of member 28 defines the lower limit of vertical travel of gate 14 when the gate 14 is set down out of the plane of the frame 12 . Latch piece 67 is a tube. A rear portion of the latch piece 67 is engaged to one end of a coil spring 72 in member 38 . The other end of the coil spring 72 is engaged within member 38 , such as to a protruding end of member 46 . A front portion 74 of latch piece 74 slides into and out of an inner open end or receiver 76 of member 26 of first side portion 20 . When latch piece 67 is in open end or receiver 76 , the gate 14 cannot be lifted relative to the frame 12 . Nor can the gate 14 be swung relative to the frame 12 because of the nature of an inner tube (latch piece 67 ) engaged within an outer tube (member 26 of first side portion 20 ). The coil spring 72 biases the latch piece 67 to the closed position. This closed relationship is shown in FIG. 3 . When latch piece 67 has been slid out of the open end 76 , the front end 74 of latch piece 67 clears the open end 76 and the gate 14 is liftable relative to the frame 12 . This open relationship is shown in FIG. 4 , and this open relationship is relative to the latch, not necessarily relative to the gate 14 , because the double stop 18 provides the next hurdle. The double stop 18 is shown in FIGS. 1 , 6 and 7 . The double stop 18 is formed generally in the shape of an inverted U. The double stop 18 is mounted on lower member 40 and in a confronting relationship to upright end member 42 . Stop 18 includes a pair of rigid sides 78 depending downwardly, with each of the sides 78 having a lower end 80 . When extension 70 is seated on seat 71 of member 26 , each of the sides 78 of double stop 18 confronts a side of member 28 . After latch piece 67 has been disengaged from open end 76 and after gate 14 has been sufficiently lifted, each of the ends 80 of double stop 18 can clear the upper surface of member 28 , thereby allowing a swinging of the gate 14 to either of the sides of the frame 12 . In operation, to open the gate 14 , the hand grabs upper member 38 with the thumb positioned on tab 64 of slide 62 , as shown in FIG. 2 . Then the thumb slides the slide 62 rearwardly to draw latch piece 67 out of the open end 74 of upper member 26 . Then the gate 14 is lifted until the double stop 18 clears the lower member 24 of the frame 12 , whereupon the gate 14 is swingable to either side of the frame 12 . Once on either side of the frame 12 , the gate 14 may be lowered, and, in such a state, the gate 14 is swingable on only one side of the frame 12 , as the double stop 18 , by virtue of hitting member 28 , prevents a swing through of the gate 14 to the other side of the frame 12 . To close the gate 14 , the gate 14 is lifted so that the double stop 18 clears member 28 and so that the double stop 18 is positioned over and aligned with member 28 . Then the slide 62 is drawn rearwardly with the thumb such that the front end 74 of the latch piece 67 can clear the open end 76 of member 26 as the gate 14 is lowered, whereupon the gate 14 is lowered until the extension 70 is seated upon seat 71 , whereupon the thumb releases the slide 62 , and whereupon the front end 74 of the latch piece 67 automatically returns into the open end 76 of member 26 such that the gate 14 is closed. It should be noted that latch mechanism 16 and double stop 18 are generally aligned vertically. Such provides a two-point connection and minimizes any swaying or tilting of the gate 14 relative to the outer frame 12 such as when a toddler pushes upon the gate 14 when closed. It should further be noted that, while the double stop 18 holds the gate 14 against a force applied perpendicular to the plane of the gate 14 , latch mechanism 16 also holds the gate 14 true against a force applied perpendicular to the plane of the gate. Latch mechanism 16 does this in two ways. First, extension 70 , formed in the shape of a half-pipe, includes side sections that confront member 26 of first side portion 20 about side sections of member 26 . This provides resistance against such a perpendicular force. Second, latch piece 67 is an inner tube that is received within an outer tube, i.e., member 26 . This also provides resistance against such a perpendicular force, as well as providing resistance against a lifting force. In other words, the extension 70 maintains member 40 in a spaced apart and parallel relationship with member 28 to provide a lower limit to vertical travel of gate 14 and further prevents a swinging of the gate 14 when the extension 70 is seated on seat 71 , as side sections of the cylindrical extension 70 are seated about side sections of tubular seat 71 . Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalents of the claims are intended to be embraced therein.	To open a two-action gate, a sliding of a latch and a lifting of the gate to disengage a double stop is required. Performing one step without the other fails to open the gate. The gate is engaged in a frame which may in turn be engaged in a partition or doorway. Via a thumb tab, a portion of the latch can be slid out of the frame. Then the gate is lifted to lift the double stop up and clear of a lower portion of the frame such the gate is swingable. The gate is journaled to a vertically running frame member which serves as the swinging and sliding axis for the gate.
You are an expert at summarizing long articles. Proceed to summarize the following text: [0001] This application is a divisional of U.S. patent application Ser. No. 11/595,465, filed on Nov. 9, 2006. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The invention relates generally to methods and packer devices that can be set within a wellbore with little or no reduction in useable cross-sectional bore area. [0004] 2. Description of the Related Art [0005] Wellbore packers are used for securing production tubing inside of casing or a liner within a wellbore. Packers are also used to create separate zones within a wellbore. Unfortunately, conventional packers and techniques for setting packers results in a reduction of usable diameter within the well. This is because the packer is carried by a conveyance tubular (such as a production tubing string) that is of smaller diameter than the tubing or casing against which it is set. The packer is then set within the annular space between the conveyance tubular and the outer tubing or casing. Once set, the useable diameter of the well (i.e., the diameter through which production fluid can flow or tools can be passed) becomes the inner diameter of the conveyance tubular. However, the components of the packer device (including slips, elastomeric seals, setting sleeves and so forth) inherently occupy space between the inner and outer tubulars. For example, a wellbore having standard 21.40 lb. casing with an outer diameter of 5 inches, would have an inner diameter of 4.126 inches. It would be desirable to run into the casing a string of tubing having an outer diameter of approximately 4 inches, which would allow for a tubing string with a large cross-section area for fluid flow and tool passage. However, the presence of presence of packer components on the outside of the tubing string will dictate that a smaller size tubing string (such as 2⅞″) be run. Over an inch of diameter in usable area is lost due to the presence of both the inner production tubing string and the packer device that is set within the space between the production tubing string and the casing. [0006] The present invention addresses the problems of the prior art. SUMMARY OF THE INVENTION [0007] The invention provides devices and methods for setting a packer inside a wellbore with little appreciable reduction of the useable area of the wellbore. In described embodiments, the outer casing or liner of the wellbore contains one or more integrated casing coupler joints having an increased diameter chamber portion. A large bore packing element is carried within the increased diameter chamber portion. The packing element may be selectively actuated to form a seal against an interior tubular member. Because the packing element is located within the chamber portion of the casing coupler, the packer may be set while saving useable cross-sectional area within the casing. In the instance of the 5 inch casing situation described above, an interior tubing string having a four inch diameter could be run into the exterior casing or liner. [0008] Rather than being conveyed into the wellbore on the tubing string, the packer device is already disposed within the well prior to running of the tubing string. They are then activated using activation components that are run into the wellbore on the tubing string. [0009] In one embodiment, the packer device comprises an axially compressible sealing element that may be formed of a ductile metal. The ductile metal may be integrated with elastomeric or non-elastomeric sealing elements, if desired. The sealing element is axially compressed by camming action by a setting sleeve member that is also located within the increased diameter portion of the casing coupler. The setting sleeve preferably includes an engagement profile that can be engaged by a complimentary engagement member, which may be integrated into the tubing string. [0010] In a second described embodiment, the compressible element of the packer device is set by a coarsely threaded setting sleeve that is helically moveably engaged with an interior surface of the casing coupler. The threaded setting sleeve includes a rotational engagement key that can be engaged by a complimentary engagement member, which may be carried on the tubing string that is inserted into the casing string. To set the packer device, the setting sleeve is rotated with respect to the casing coupler. [0011] In a third described embodiment, the element is set by moveable conical surface that urges the sealing element radially inwardly and against the tubing string. In further exemplary embodiments, the packer device is set by an energizing setting power source that is retained within the wellbore casing and preferably within the casing coupler itself. The power source can comprise a fluid chamber or a compressed spring. The tubing string is adapted to release or energize the stowed energy source. The release or energization may be accomplished a number of ways, including the use of a latch member to engage a portion of the energy source and release it or by use of a tag device, such as an RFID (radio frequency identification) tag that will release or energize the power source upon electronic recognition. If desired, a delay could be incorporated into the setting mechanism. [0012] In a further described embodiment, the packer device is actuated hydraulically via fluid that is pumped down the production tubing string and into the enlarged diameter chamber. In still another described embodiment, a ductile tube is attached to the tubing string and, by hydraulic or mechanical methods, the ductile tube is inflated radially outwardly and forms a metal-to-metal or metal-to-non-metal seal with the sealing device contained within the casing coupler. BRIEF DESCRIPTION OF THE DRAWINGS [0013] For a thorough understanding of the present invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings in which like reference characters designate like or similar elements throughout the several figures of the drawing. [0014] FIG. 1 is a side, cross sectional view of an exemplary packer device constructed in accordance with the present invention. [0015] FIG. 2 is a side, cross sectional view of the packer device shown in FIG. 1 , now having been set. [0016] FIG. 3 is a side, cross-sectional view of an alternative packer device constructed in accordance with the present invention. [0017] FIG. 4 is a side, cross-sectional view of the packer device shown in FIG. 3 , now with having been set. [0018] FIG. 5 is a side, cross-sectional view of a further alternative packer device constructed in accordance with the present invention. [0019] FIG. 6 is a side, cross-sectional view of the packer device shown in FIG. 5 , now having been set. [0020] FIG. 7 is a side, cross-sectional view of an alternative packer device constructed in accordance with the present invention and utilizing a hydraulic setting arrangement for setting the packer device. [0021] FIG. 8 is a side, cross-sectional view of the packer device shown in FIG. 7 , now having been actuated to a set position. [0022] FIG. 9 is a side, cross-sectional view of an alternative packer device also utilizing a hydraulic setting arrangement. [0023] FIG. 10 is a side, cross-sectional view of the packer device shown in FIG. 9 , now having been actuated to a set position. [0024] FIG. 11 is a side, cross-sectional view of a further exemplary packer device which incorporates a ductile, radially expandable tube. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0025] FIGS. 1 and 2 illustrate an exemplary wellbore 10 that has been drilled through the earth 12 . The wellbore 10 is lined with a string of casing, of which two casing sections 14 , 16 are depicted. A casing coupler 18 interconnects the casing sections 14 , 16 to form a casing string 17 that defines a central bore 19 along its length. Cement 20 surrounds the casing sections 14 , 16 and casing coupler 18 . It is noted that the casing coupler 18 has a greater diameter than the casing sections 14 , 16 and is secured to each of the casing sections 14 , 16 via threaded connections 22 , 24 , respectively. [0026] The casing coupler 18 includes an axial bore 26 for passage of tools and fluid through the casing coupler 18 . The bore 26 has an enlarged diameter chamber portion 28 . A packer device 30 is disposed within the enlarged diameter chamber portion 28 . The packer device 30 includes a cylindrical elastomeric packer sealing element 32 and a cylindrical setting sleeve 34 . The setting sleeve 34 is a compression member that is axially moveable within the enlarged diameter portion 28 of the bore 26 . The setting sleeve 34 features an axial bore 36 with an engagement profile 38 within. A ratchet-style body lock ring assembly 37 , of a type known in the art, is associated with the outer radial diameter surface of the setting sleeve 34 . The body lock ring assembly 37 provides for limited one-way movement of the setting sleeve 34 with respect to the surrounding casing coupler 18 . [0027] FIGS. 1 and 2 depict actuation of the packer device 30 to create a seal between the casing string 17 and a string of production tubing 40 , the lower end of which is visible in FIG. 2 . The lower end of the production tubing string 40 includes a setting tool 42 for actuation of the packer device 30 . In FIG. 1 , the packer device 30 is in an initial, unset position. In one embodiment, the setting tool 42 includes a cylindrical tool body 44 having a plurality of collets 46 extending axially therefrom. Each of the collets 46 carries a radially enlarged portion 48 that presents a stop shoulder 50 and a tapered camming surface 52 . The enlarged portion 48 is shaped and sized to fit within the engagement profile 38 of the setting sleeve 34 . [0028] To activate the packer device 30 , the production tubing string 40 and setting tool 42 are inserted into the casing string 17 . The tapered camming surface 52 of each collet 46 will contact the upper ends of the sealing element 32 and the setting sleeve 34 and deflect the collet 46 radially inwardly. When the radially enlarged portion 48 of each collet 46 becomes aligned with the engagement profile 38 of the setting sleeve 34 , each collet 46 will snap radially outwardly so that the radially enlarged portion 48 becomes disposed within the engagement profile 38 , as shown in FIG. 2 . Once the setting tool 42 is attached to the setting sleeve 34 in this manner, the tubing string 40 is then pulled upwardly to cause the setting sleeve 34 to be moved axially upwardly within the enlarged diameter portion 28 of the bore 26 . The collets 46 are not disengaged from the engagement profile 38 due to abutting contact between the stop shoulder 50 and the upper end 54 of the profile 38 . The 38 . The sealing element 32 is thereby axially compressed by the setting sleeve 34 and, when axially compressed, will be extruded radially inwardly against the tool body 44 of the production tubing string 40 . The body lock ring assembly 37 will prevent the setting sleeve 34 from moving back downwardly with respect to the surrounding casing coupler 18 , thereby preventing the packer device 30 from becoming unset. [0029] Because the components of the packer device 30 are retained within an enlarged diameter portion 28 of the casing coupler 18 , the gap between the exterior of the tubing string 40 and the interior of the casing string 17 can be quite small. For example, in a casing string made up of 35.3 lb. Casing sections with an external diameter of 5 inches, an interior diameter of 4.126 inches would be available. With the large bore, external packer arrangement described above, it would be possible to insert a tubing string 17 having a diameter approximating 4 inches, rather than a smaller diameter tubing string (i.e., 2⅞″). In fact, the use of a larger diameter tubing string is desirable for two reasons. First, the resulting available cross-sectional flow and work bore area of the tubing string 17 will be larger. Second, the sealing element 32 of the packer device 30 can more easily and securely seal against the larger diameter tubing string 17 . [0030] FIGS. 3 and 4 illustrate an alternative embodiment of the invention wherein a packer device 30 ′ has a sealing element 32 and a setting sleeve assembly 60 . The setting sleeve assembly 60 includes an inner setting sleeve member 62 having an external helical thread 64 and an internal helical thread 66 that is formed on the interior of the enlarged diameter portion 28 . It is noted that the external and internal threads 64 , 66 are interengaged with one another in a well-known manner such that rotation of the sleeve member 62 within the casing coupler 18 will move the sleeve member 62 axially within the coupler 18 . One or more key slots 68 are located on the radial interior of the sleeve member 62 . [0031] In FIG. 3 , the packer device 30 ′ is in an unset, initial position. In FIG. 4 , a production tubing string 40 has been inserted into the casing string 17 . A setting component 70 is secured to the lower end of the production tubing string 40 and presents radially extending keys 72 that are shaped and sized to fit within the key slots 68 . It is noted that the keys 72 are preferably spring-biased radially outwardly from the body of the setting component 70 so that they may be compressed radially inwardly as needed for disposal down through the casing string 17 and to pop radially outwardly upon encountering the key slots 68 . When the keys 72 are located within the key slots 68 , the inner sleeve member 62 is secured rotationally with respect to the setting component 70 such that rotating the tubing string 40 and setting component 70 will rotate the sleeve member 62 . In order to set the packer device 30 ′, the tubing string 40 is rotated at the surface to cause the sleeve member 62 to move axially upwardly with respect to the casing coupler 18 , thereby radially compressing the sealing element 32 and causing it to seal against the tubing string 40 . In this embodiment, no body lock ring is required to maintain the packer device 30 ′ in the set position. The inward compressive force exerted by the sealing element 32 upon the outer radial surface of the tubing string 40 should be sufficient to prevent counter-rotation of the tubing string 40 within the casing string 17 that might cause the packer device 30 ′ to become unset. [0032] FIGS. 5 and 6 depict a further alternative embodiment for a packer device 30 ″ constructed in accordance with the present invention. The packer device 30 ″ includes a sealing element 72 having a ductile metallic body 74 and elastomeric sealing portions 76 . A A suitable sealing element of this type is the “ZX” packing element that is available commercially from Baker Oil Tools of Houston, Tex. It is noted that the exterior radial surface 77 of the sealing element 72 is substantially conical in shape such that the lower axial end 78 of the sealing element 72 presents a smaller diameter than the upper axial end 80 . [0033] Also included in the packer device 30 ″ is a setting sleeve member 82 having a generally cylindrical sleeve body 84 that defines a central axial bore 86 with an interior engagement profile 88 . A body lock ring assembly 37 is associated with the outer radial surface of the sleeve body 84 and provides for limited one-way movement of the setting sleeve member 82 with respect to the surrounding casing coupler 18 . A tapered bore portion 90 is located proximate the upper end 92 of the body 84 thereby providing a ramped surface that is in abutting contact with the outer radial surface 77 of the sealing element 72 . [0034] FIG. 5 depicts that packer device 30 ″ in an unset condition. In FIG. 6 , a production tubing string 40 has been disposed into the casing string 17 . A setting tool component 94 is secured to the lower end of the tubing string 40 and presents axially extending collets 96 with radially outwardly projecting portions 98 that are shaped and sized to reside within the engagement profile 88 of the setting sleeve member 82 . As the tubing string 40 is lowered through the casing string 17 , the collets 96 are deflected radially inwardly until the outwardly projecting portions 98 encounter the engagement profile 88 and snap radially outwardly to reside within the engagement profile 88 to secure the tubing string 40 to the setting sleeve member 82 . Then, the tubing string 40 is raised to cause the setting sleeve member 82 and urge the ramped surface of tapered bore portion 90 axially against the outer radial surface 77 of the sealing element 72 . This axial movement causes the body the body 74 of the sealing element 72 to be cammed radially inwardly and deformed radially inwardly against the production tubing string 40 . Operation of the body lock ring assembly 37 will maintain the packer assembly 30 ″ in the set position. [0035] Variations on the packer device 30 ″ are possible wherein the sealing element 72 is formed entirely of metal and without the elastomeric sealing portions 76 . When the packer device 30 ″ is set, a metal-to-metal seal is formed. Such a variation may be advantageous in many instances wherein, for example, there is a minimum amount of movement of the components needed to form an effective seal. Where a fully metallic sealing element is employed, the sealing element may be a bellow-type seal or a hydroformed seal or ring element. Additionally, a metal-to-metal seal may incorporate toothed slips, of a type known in the art, or other mechanisms for creating a biting engagement between the tubing string 40 and the surrounding casing string 17 . [0036] Currently, each of the packer devices 30 , 30 ′ and 30 ″ are permanently set packer devices. They may be removed from the wellbore, if desired, by use of a suitable milling tool, as is known in the art. [0037] FIGS. 7 and 8 illustrate a further exemplary packer device 100 that employs an energy source that is contained within the casing string 17 prior to disposing the tubing string 40 into the casing string 17 . The enlarged diameter chamber 28 of the casing coupler 18 contains an outer collar 102 and an inner collar 104 . The inner collar 104 is disposed radially within the outer collar 102 , and a chamber 106 is defined radially between the two collars 102 , 104 . Flanged end portions 108 and seals 110 are provided for each of the collars 102 , 104 . The outer collar 102 presents an upper axial end portion 112 that lies in contact with the sealing element 32 . A recess 114 is inscribed within the interior radial surface 116 of the outer collar 102 . An annular seal member 118 is fixedly secured to the inner collar 104 and is, in turn, secured to a split ring, or C-ring member 120 . In the unset position, depicted in FIG. 7 , the split ring 120 resides within the recess 114 of the outer collar 102 . As noted, the chamber 106 is defined radially between the inner and outer collars 102 , 104 , at its upper end by seal 110 , and at its lower end by seal member 118 . A split ring actuator 122 (visible in FIG. 7 ) is operably interconnected with the split ring 120 . The split ring actuator 122 preferably comprises a programmable electronic transceiver that is designed to receive a triggering signal from a transmitter. Signal transmitter 124 is incorporated within the tubing string 40 . In one currently preferred embodiment, the signal transmitter 124 may comprise an RFID (radio frequency identification) tag or chip which is designed to emit a triggering signal upon passing within a certain proximate distance of the actuator 122 . The actuator 122 is operably associated with the split ring 120 to retract the split ring 120 radially inwardly and out of the recess 114 upon receipt of the signal from the transmitter 124 . Radial retraction of the split ring 120 may be done by the actuator mechanically, magnetically, or using other suitable known techniques. [0038] The chamber 106 may be an atmospheric chamber or a more highly pressurized chamber, which will create a pressure differential across the seal member 118 which will urge the end portion 112 of the outer collar 102 toward the sealing element 32 and a set position. In variations on this embodiment, the chamber 106 could be replaced with a mechanical spring to serve as an energy source to bias the outer collar 102 toward the sealing element 32 . Additionally, the transmitter 124 and actuator 122 could be replaced by a mechanical trigger arrangement wherein the spring is mechanically released from a compressed state by engaging a release latch for the spring with an engagement member within the tubing string 40 . [0039] In operation, the packer device 100 is in the initially unset position shown in FIG. 7 . The tubing string 40 is lowered into the casing string 17 until the transmitter 124 is located proximate the actuator 122 . The triggering signal is received by the actuator 122 , which then releases the split ring 120 from the recess 114 . If desired, a delay could be incorporated into the programming of the actuator 122 such that a predetermined period of time elapses between the time the triggering signal is received by the actuator 122 and the split ring 120 is released from the recess 114 . When the split ring 120 is released from the recess 114 , fluid pressure within the chamber 106 will urge the outer collar 102 axially upwardly so that the upper end 112 will compress the sealing element 32 . The sealing element 32 will be deformed radially inwardly to seal against the tubing string 40 , as depicted in FIG. 8 to create a seal. [0040] Referring now to FIGS. 9 and 10 , a further exemplary packer device 130 is depicted which utilizes hydraulic setting via the tubing string 40 . The sealing element 32 is retained within the chamber 28 along with a setting piston 132 . The setting piston 132 features an enlarged compression head portion 134 that abuts the sealing element 32 and a reduced diameter stem portion 136 that extends downwardly from the head portion 134 . A ratchet mechanism 138 is located at its lower end of the stem portion 136 and operates in the manner of a body lock ring to ensure one-way sequential movement of the setting piston 132 with respect to the surrounding casing coupler 18 . [0041] A fluid chamber 140 is defined between the setting piston 132 and the casing string 17 within the enlarged chamber 28 . Fluid flow ports 142 are disposed through the setting piston 132 to permit fluid communication between the fluid chamber 140 and the interior flowbore 144 of the setting piston 132 . Fluid seals 146 are provided between the setting piston 132 and the casing coupler 18 to ensure fluid tightness of the fluid chamber 140 . [0042] The lower end of the tubing string 40 is closed off by a plug 148 . The plug 148 is preferably a temporary or removable plug which can be removed to allow flow through the tubing string 40 at a later point during production operations. Ports 150 are disposed through the side of the tubing string 40 . [0043] In operation, the packer device 130 is initially in the unset position depicted in FIG. 9 . The tubing string 40 is then disposed into the casing string 17 until the ports 150 of the tubing string 40 are generally aligned with the fluid flow ports 142 in the setting piston 132 . The interior flowbore 152 of the tubing string 40 is then pressurized so that fluid is flowed through the aligned ports 150 and 142 and into the fluid chamber 140 . The setting piston 132 is urged upwardly by the fluid pressure so that the enlarged head portion 134 compresses the sealing element 32 . Axial compression of the sealing element 32 causes the sealing element 32 to deform radially inwardly and seal against the tubing string 40 , as depicted in FIG. 10 . The ratchet mechanism 138 ensures that the packer device 130 remains in the set position. [0044] FIG. 11 depicts a further exemplary embodiment of the invention wherein a sealing element 200 is contained within the chamber 28 of the casing coupler 18 and an inflatable, or radially expandable, ductile tube 201 is made up into the production tubing string 40 . The ductile tube 201 is formed of a material that permits the tube 201 , or portions thereof, to be deformed radially outwardly. One such material is a nickel alloy. To create a create a seal, the ductile tube 201 is inflated or expanded radially outwardly until its radially outer surface is brought into sealing contact with the sealing element 200 . The ductile tube 201 can be inflated or expanded radially outwardly using a number of techniques for radially expanding ductile tubular members. One technique for inflating the ductile tube 201 is to seat a dart, ball, or other pug member 202 upon a seat 204 to seal off the flowbore 152 of the tubing string 40 below the ductile tube 201 . Fluid pressure is then increased within the flowbore 152 above the plug member 202 to cause the ductile tube 201 to expand radially outwardly, as illustrated in FIG. 11 . In this embodiment, as well, the plug member 202 may be a temporary or removable plug member. Alternatively, a mechanical means, such as a suitable swaging instrument, can be used to radially expand the ductile tube 201 radially outwardly. [0045] The sealing element 200 may be a metallic sealing element or a non-metallic sealing element. In one embodiment, the sealing element 200 is an elastomeric sealing element. In another embodiment, the sealing element 200 is a mechanical sealing element and contains toothed portions to form a biting engagement with the ductile tube 201 . The design of the sealing element 200 will preferably provide fluid sealing and mechanical retention between the inflatable tubing 201 and the casing coupler 18 . The sealing contact between the ductile tube 201 and the sealing element 200 forms a retention device between the tubing string 40 and the surrounding casing string that is capable of withstanding high axial tubing loads. [0046] Those of skill in the art will appreciate that the present invention provides a novel wellbore packer arrangement as well as a wellbore production system that includes an outer tubular string having an enlarged diameter chamber portion; an inner tubular string; and a and a packer device disposed at least partially within the enlarged chamber to form a seal against the inner tubular string. [0047] The present invention also provides methods of establishing a seal between inner and outer tubular string members within a wellbore wherein a packer device is disposed within an enlarged diameter chamber portion of an outer tubular string. The outer tubular string, such as a string of casing or liner, is run into a wellbore and cemented in place. At this point the packer device is in an unset position. Next, the inner tubular string is run into the outer tubular string to a predetermined depth or position within the outer string. The predetermined depth or position will typically correspond to the proper location of a tool, such as a production nipple, inside the outer tubular string. The packer device is then actuated from an unset to a set position to form a seal against a member of the inner tubular string. [0048] Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.	Devices and methods for setting a packer inside a wellbore with little appreciable reduction of the useable area of the wellbore. The outer casing or liner of the wellbore contains one or more integrated casing coupler joints having an increased diameter chamber portion. A large bore packing element is carried within the increased diameter chamber portion. The packing element may be selectively actuated to form a seal against an interior tubular member. Because the packing element is located within the chamber portion of the casing coupler, the packer may be set while saving useable cross-sectional area within the casing.
You are an expert at summarizing long articles. Proceed to summarize the following text: RELATED APPLICATION [0001] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 61/616,002, filed Mar. 27, 2012, which is incorporated by reference herein in its entirety. FIELD OF THE INVENTION [0002] The present invention relates to a movable panel assembly with a power sliding drive mechanism. More particularly, the present invention relates to a movable panel assembly with a power sliding drive mechanism for a flush-flush closing vehicle sliding panel. BACKGROUND OF THE INVENTION [0003] Pickup trucks and other related vehicles have a rear window, or backlite, that is mounted in a vehicle body aperture, immediately behind the seats in the vehicle passenger compartment. Many of the backlites are built with one or two slider panels that ride in slider tracks, while opening or closing across a portion of a window aperture. [0004] The slider panels may be moved manually or automatically across the window aperture. When automatically driven, the slider panels may be moved by a window regulator, for example, like that disclosed in U.S. Pat. No. 6,119,401 to Lin (hereinafter Lin). [0005] For the Lin device, there is a cable having a powered regulator attached to one cable end and a carrier block that is physically attached at another cable end, wherein the carrier block has a female carrier socket. In conjunction with the carrier block, an attachment block is rigidly mounted to a slidable window pane, wherein the attachment block has a male engagement stud that is loosely disposed within the female carrier socket. Consequently, when the Lin window regulator is powered for movement of the cable, the carrier socket and the engagement stud come into mating engagement that results in sliding movement of the slidable window pane. Such an arrangement is noisy, where the powered window regulator loosely drives the slidable window pane. Because of the many parts involved, the Lin window regulator has high material and labor costs. [0006] Some slider assemblies are further designated as being flush where a sliding panel is in the plane of the fixed panel(s), when the sliding panel completely closes the backlite opening, or the complete window assembly may be in the plane of a vehicle body panel. Various ways to achieve flush orientation to fixed panels are, for example, by utilizing guide pins, ramps, and cams to move the sliding panel into the backlite opening. [0007] An example of a horizontal sliding assembly that moves its sliding panel into the plane of a fixed panel, when the sliding panel completely closes the backlite opening, is U.S. Pat. No. 4,561,224 to Jelens (hereinafter, Jelens), which teaches a sliding window assembly having opposed longitudinally spaced first and second guide pins on the top and bottom of a slidable window that are adapted for sliding motion within corresponding first and second tracks respectively, as shown, for example, in Jelens' FIGS. 2-5 and 7 . [0008] Even further, some sliding assemblies are designated as being flush-flush, wherein the sliding panel is not only flush within the sliding assembly itself (i.e., the sliding panel being in the same plane as fixed panels) but the sliding assembly would also be in the same plane as an outer vehicle body panel. U.S. Pat. No. 7,641,265 to Seiple (hereinafter Seiple) is an example of a flush-flush sliding assembly, which is incorporated herein by reference in its entirety. [0009] What is sought is a powered sliding assembly that directly, smoothly, and with less resistance drives a sliding panel with little noise. While achieving these benefits, it is desired for such a powered sliding assembly to be simple in design, thereby having few parts in order to reduce material and labor costs. Such a sliding assembly should also be capable of being flush-flush in design. SUMMARY OF THE INVENTION [0010] A powered sliding drive assembly is provided having a fixed panel that defines a window opening, a sliding panel that is movable between a closed position covering the window opening and an open position. The sliding panel has a frame member secured around at least a portion of the periphery of the sliding panel, wherein the sliding panel defines a plane. The powered sliding drive assembly also has at least one guide pin extending substantially vertically downwardly from a portion of the frame member, which is disposed on a bottom portion of the sliding panel. There is also at least one cable connected at a first end to the guide pin, to the frame member, or to both, and a second end connected to a sliding panel drive unit. As a result, at least the first end of the cable is in the plane of the sliding panel. [0011] The powered sliding drive assembly may further be provided with at least one track, wherein the sliding panel has at least one pin positioned in the track and the sliding panel is located in a flush-flush position with a fixed panel and a vehicle body panel. The pin may also have a washer disposed on it, thereby providing smooth and quiet movement of the sliding panel. [0012] Further objects and advantages of the present invention will be apparent from the following description and appended claims, reference being made to the accompanying drawings forming a part of a specification, wherein like reference characters designate corresponding parts of several views. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 is an elevation view of a bottom corner of a sliding panel with a frame, pin, and cable that is disposed within the frame in accordance with the present invention; [0014] FIG. 2 is an elevation view of a bottom corner of a sliding panel with a frame, washer, pin, and cable that is disposed within the frame in accordance with the present invention; [0015] FIG. 3 is an elevation view of a bottom corner of a sliding panel with a frame, pin, and cable that is disposed within the pin in accordance with the present invention; [0016] FIG. 4 is an elevation view of a bottom corner of a sliding panel with a frame, washer, pin, and cable that is disposed within the pin in accordance with the present invention; [0017] FIG. 5 is an elevation view of a bottom corner of a sliding panel with a frame, pin, and two cables where one cable is disposed within the frame and the other cable is disposed within the pin in accordance with the present invention; [0018] FIG. 6 is an elevation view of a bottom corner of a sliding panel with a frame, pin, washer, and two cables where one cable is disposed within the frame and the other cable is disposed within the pin in accordance with the present invention; [0019] FIG. 7 is an elevation view of a bottom corner of a slider panel with a frame, pin, and cable that is disposed onto the frame in accordance with the present invention; [0020] FIG. 8 is an elevation view of a bottom corner of a sliding panel with a frame, washer, pin, and cable that is disposed onto the washer in accordance with the present invention; [0021] FIG. 9 is an elevation view of a bottom corner of a sliding panel with a frame, pin, collar, and cable that is disposed onto the collar in accordance with the present invention; [0022] FIG. 10 is an elevation view of a bottom corner of a sliding panel with a frame, pin, washer, collar, and cable that is disposed onto the collar in accordance with the present invention; [0023] FIG. 11 is an elevation view of a bottom corner of a sliding panel with a frame, pin, collar, and two cables where one cable is disposed onto the frame and the other cable is disposed onto the collar in accordance with the present invention; [0024] FIG. 12 is an elevation view of a bottom corner of a sliding panel with a frame, pin, washer, collar, and two cables where one cable is disposed onto the frame and the other cable is disposed onto the collar in accordance with the present invention; [0025] FIG. 13 is a perspective side view of the bottom corner of the sliding panel of FIG. 7 with a power drive, external body panel, and seal; [0026] FIG. 14 is a perspective view of a sliding panel with upper and lower tracks in accordance with the present invention; [0027] FIG. 15 is a perspective view of a prior art sliding window assembly having two fixed panels and a track; and [0028] FIG. 16 is an elevation view of a single fixed panel assembly in accordance with the present invention. DESCRIPTION OF THE INVENTION [0029] It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless the claims expressly state otherwise. [0030] FIG. 1 illustrates a bottom corner of a sliding panel assembly 10 having a frame 12 , pin 16 , and cable 18 , where the cable 18 is disposed in the frame 12 , as viewed from within a vehicle compartment 21 (see FIG. 15 ). The cable 18 has a bead 20 intimately connected on an end thereof, the bead 20 being disposed within a cavity 24 of the frame 12 . The sliding panel assembly 10 also comprises a sliding panel 25 , which together with the frame 12 defines a plane. All fixed panels or sliding panels of the present invention may comprise glass or plastic, but preferably glass. These fixed panels or sliding panels may at least be transparent or translucent. As indicated by the right pointing arrow, the bead 20 cooperates with the cavity 24 to allow for smooth and quiet pulling of the sliding panel assembly 10 to the right by the cable 18 , which is attached to a drive unit 290 (see FIG. 13 ). [0031] Although the cable 18 and bead 20 are shown in a pre-formed cavity in the frame 12 in FIG. 1 , these items 18 , 20 could be molded into the frame 12 and yet the invention would function the same as described above. This applies to all cables with beads for the present invention. The cable 18 is in the plane of the sliding panel 25 and frame 12 . [0032] FIG. 2 illustrates a bottom corner of a sliding panel assembly 30 having a frame 32 , shoulder or washer 34 , pin 36 , and cable 38 that is disposed in the frame 32 . The cable 38 has a bead 40 intimately disposed on an end thereof, the bead 40 being disposed within a cavity 44 that is defined within the frame 32 . The sliding panel assembly 30 also comprises a sliding panel 45 , which together with the frame 32 defines a plane. [0033] Functionally, with the washer 34 disposed about a top of the pin 36 , the bead 40 cooperates with the cavity 44 and the washer 34 , which is disposed onto the frame 32 at the top of the pin 36 , to smoothly and quietly allow for pulling the sliding panel assembly 30 to the right (as indicated by the right pointing arrow) by the cable 38 , which is attached to the drive unit 290 . The cable 38 is in the plane of the sliding panel 45 and frame 32 . [0034] FIG. 3 illustrates a bottom corner of a sliding panel assembly 50 having a frame 52 , pin 56 , and cable 58 that is disposed in the pin 56 . The cable 58 has a bead 60 intimately disposed on an end thereof, the bead 60 being disposed within a cavity 64 that is defined within the pin 56 . The sliding panel assembly 50 also comprises a sliding panel 65 , which together with the frame 52 defines a plane. The bead 60 cooperates with the cavity 64 to smoothly allow for pulling the sliding panel assembly 50 to the right (as indicated by the right pointing arrow in the figures) by the cable 58 , which is attached to the drive unit 290 . [0035] In FIG. 3 , a dimension H1 represents a clearance necessary between the bottom of the frame 52 and the cable, so that the cable 58 does not interfere with a track (see, for example, tracks 282 , 284 of FIG. 14 ) during the cable's operation of pulling the sliding panel assembly 50 . Similarly, the clearance H1 is present in the embodiment of FIG. 5 . The cable 58 is in the plane of the sliding panel 65 and frame 52 . [0036] FIG. 4 illustrates a bottom corner of a sliding panel assembly 70 having a frame 72 , shoulder or washer 74 , pin 76 , and cable 78 that is disposed in the pin 76 . The cable 78 has a bead 80 intimately disposed on an end thereof, the bead 80 being disposed within a cavity 84 that is defined within the pin 76 . The sliding panel assembly 70 also comprises a sliding panel 85 , which together with the frame 72 defines a plane. The bead 80 cooperates with the cavity 84 and the washer 74 , which is disposed about the top of the pin 76 , to smoothly allow for pulling the sliding panel assembly 70 to the right (as indicated by the right pointing arrow) by the cable 78 , which is attached to the drive unit 290 . [0037] In FIG. 4 , a dimension H2 represents the clearance necessary between the bottom of the washer 74 and the cable 78 , so that the cable 78 does not interfere with a track (see, for example, tracks 282 , 284 of FIG. 14 ) during the cable's operation of pulling the sliding panel assembly 70 . Similarly, the clearance H2 is present in the embodiment of FIG. 6 . The cable 78 is in the plane of the sliding panel 85 and frame 72 . [0038] FIG. 5 illustrates a bottom corner of a sliding panel assembly 90 having a frame 92 , pin 96 , and cables 98 , 102 that are respectively disposed in the frame 92 and pin 96 . The sliding panel assembly 90 also comprises a sliding panel 105 , which together with the frame 92 defines a plane. The cables 98 , 102 respectively have beads 100 , 106 intimately disposed on an end thereof, the beads 100 , 106 being respectively disposed within cavities 104 , 108 that are respectively defined within the frame 92 and pin 96 . The cables 98 , 102 are in the plane of the sliding panel 105 and frame 92 . [0039] It should be noted that although the cable 98 is shown in a low vertical position on the frame, the present invention is not limited to a cable (e.g., 98 , 118 , 222 , 242 ) at this vertical position along the edge of the frame 92 . In fact, the cable 98 could be located at the upper edge of the frame 92 . Selectively locating the frame cables of the instant invention anywhere along the vertical edge of a frame or, for that matter, the top pins (e.g., 276 a,b of FIG. 14 ) applies to all embodiments of the present invention, where the cables 18 , 38 , 98 , 118 , 138 , 222 , 242 , 278 c,d , are attached directly to their corresponding frames 12 , 32 , 92 , 112 , 132 , 212 , 232 , 272 . [0040] The beads 100 , 106 respectively cooperate with the cavities 104 , 108 to more smoothly allow for pulling the sliding panel assembly 90 to the right (as indicated by the right pointing arrows), by the cables 98 , 102 which are attached to the drive unit 290 , via pulleys 292 , 294 . It has herein been found that by utilizing both cables 98 , 102 in such a manner provides a more uniform and balanced pull force on the sliding panel assembly 90 . [0041] FIG. 6 illustrates a bottom corner of a sliding panel assembly 110 having a frame 112 , shoulder or washer 114 , pin 116 , and cables 118 , 122 that are respectively disposed in the frame 112 and pin 116 . The washer 114 disposed onto the frame 112 at the top of the pin 116 . The sliding panel assembly 110 also comprises a sliding panel 125 , which together with the frame 112 defines a plane. The cables 118 , 122 respectively have beads 120 , 126 intimately disposed on an end thereof, the beads 120 , 126 being respectively disposed within cavities 124 , 128 that are respectively defined within the frame 112 and pin 116 . The cables 118 , 122 are in the plane of the sliding panel 125 and the frame 112 . [0042] The beads 120 , 126 respectively cooperate with the cavities 124 , 128 to more smoothly allow for pulling the sliding panel assembly 110 to the right (as indicated by the right pointing arrows) by the cables 118 , 122 which are attached to the drive unit 290 and pulleys 292 , 294 , because it has been found that conjunctively utilizing both cables 118 , 122 in this manner provides a more uniform and balanced pull force on the sliding panel assembly 110 . [0043] FIG. 7 illustrates a bottom corner of a sliding panel assembly 130 having a frame 132 , pin 136 , and cable 138 that is disposed directly into the frame 132 . The cable 138 may be disposed by connecting means such as screw attachment, adhesive bonding, welding, and molding (not shown but common in the art). The cable 138 is in intimate contact with the frame 132 . The sliding panel assembly 130 also comprises a sliding panel 145 (comprised, for example, of glass or plastic), which together with the frame 132 defines a plane. The frame 132 cooperates with the cable 138 to allow for smooth pulling of the sliding panel assembly 130 to the right by the cable 138 , which is attached to the drive unit 290 and pulleys 292 , 294 . The cable 138 is in the plane of the sliding panel 145 and the frame 132 . [0044] FIG. 8 illustrates a bottom corner of a sliding panel assembly 150 having a frame 152 , shoulder or washer 154 , pin 156 , and cable 158 that is disposed into the washer 154 . The cable 158 is in intimate contact with the washer 154 . The sliding panel assembly 150 also comprises a sliding panel 165 , which together with the frame 152 defines a plane. The washer 154 , which is disposed on the frame 152 at the top of the pin 156 , cooperates with the cable 158 to smoothly allow for pulling the sliding panel assembly 150 to the right by the cable 158 , which is attached to the drive unit 290 and pulleys 292 , 294 . The cable 158 is in the plane of the sliding panel 165 and the frame 152 . [0045] FIG. 9 illustrates a bottom corner of a sliding panel assembly 170 having a frame 172 , pin 176 , collar 180 , and cable 178 , which cable 178 may be disposed onto the collar 180 , by connecting means such as screw attachment, adhesive bonding, welding, and molding (not shown but common in the art). The cable 178 is in intimate contact with the collar 180 . The sliding panel assembly 170 also comprises a sliding panel 185 (comprised, for example, of glass or plastic), which defines a plane. The collar 180 cooperates with the cable 178 to allow for smooth pulling of the sliding panel assembly 170 to the right by the cable 178 , which is attached to the drive unit 290 and pulleys 292 , 294 . [0046] In FIG. 9 , a dimension H3 represents the clearance necessary below the frame 172 so that the cable 178 and collar 180 do not interfere with a track (see example tracks 282 , 284 of FIG. 14 ) during the cable's operation of pulling the sliding panel assembly 170 . Similarly, clearance H3 is also present in the embodiment of FIG. 11 . The cable 178 is in the plane of the sliding panel 185 and the frame 172 . [0047] FIG. 10 illustrates a bottom corner of a sliding panel assembly 190 having a frame 192 , shoulder or washer 194 , pin 196 , collar 200 , and cable 198 that is disposed onto the collar 200 . The cable 198 is in intimate contact with the collar 200 . The sliding panel assembly 190 also comprises a sliding panel 205 , which together with the frame 192 defines a plane. The collar 200 cooperates with the cable 198 to allow for smooth pulling of the sliding panel assembly 190 to the right by the cable 198 , which is attached to the drive unit 290 and pulleys 292 , 294 . [0048] In FIG. 10 , a dimension H4 represents the clearance necessary between the washer 194 , which is disposed on the frame 192 at the top of the pin 196 , and the collar 200 so that the cable 198 and collar 200 do not interfere with a track (see, for example, tracks 282 , 284 of FIG. 14 ) during the cable's operation of pulling the sliding panel assembly 190 . Similarly, clearance H4 is also present in the embodiment of FIG. 12 . The cable 198 is in the plane of the sliding panel 205 and the frame 192 . [0049] FIG. 11 illustrates a bottom corner of a sliding panel assembly 210 having a frame 212 , pin 216 , collar 220 with a cable 218 disposed thereon, and cable 222 that is disposed onto the frame 212 . The cables 218 , 222 may be disposed by connecting means such as screw attachment, adhesive bonding, welding, and molding. The cables 218 , 222 are respectively in intimate contact with the collar 220 or frame 212 . The sliding panel assembly 210 also comprises a sliding panel 225 , which together with the frame 212 defines a plane. [0050] The collar 220 cooperates with the cable 218 and the frame 212 cooperates with the cable 222 to allow for more smoothly pulling of the sliding panel assembly 210 to the right by the cables 218 , 222 which are attached to the drive unit 290 and pulleys 292 , 294 . It has herein been found that by utilizing both cables 218 , 222 in such a manner provides a more uniform and balanced pull force on the sliding panel assembly 210 . The cables 218 , 222 are in the plane of the sliding panel 225 and the frame 212 . [0051] FIG. 12 illustrates a bottom corner of a sliding panel assembly 230 having a frame 232 , shoulder or washer 234 , pin 236 , collar 240 with a cable 238 that is disposed thereon, and cable 242 that is disposed onto the frame 232 at the top of the pin 236 . The cables 238 , 242 may be disposed by connecting means such as screw attachment, adhesive bonding, welding, and molding. The cables 238 , 242 are respectively in intimate contact with the collar 240 or frame 232 . The sliding panel assembly 230 also comprises a sliding panel 245 , which together with the frame 232 defines a plane. [0052] The collar 240 cooperates with the cable 238 and the frame 232 cooperates with the cable 242 to allow for more smoothly pulling of sliding panel assembly 230 to the right by the cables 238 , 242 which are attached to the drive unit 290 and pulleys 292 , 294 . It has herein been found that by utilizing both cables 238 , 242 in such a manner provides a more uniform and balanced pull force on the sliding panel assembly 230 . The cables 238 , 242 are in the plane of the sliding panel 245 and the frame 232 . [0053] FIG. 13 illustrates a side perspective view of a possible embodiment of the sliding panel assembly 130 of FIG. 7 . In this embodiment of FIG. 13 , the frame 132 , pin 136 , cable 138 , and sliding panel 145 , cooperate with a vehicle body panel 144 and external seal 146 to seal a fixed panel opening 313 (see FIG. 15 ) from an intrusion of moisture from the exterior of a vehicle (see vehicle 25 in FIG. 7 of Seiple). FIG. 13 illustrates the cable 138 attached to the frame 132 , which would look similar in a side view for cables 18 , 38 , 58 , 78 , 98 , 118 , 122 , 138 , 158 , 178 , 198 , 218 , 222 , 238 , and 242 to their respective frames, washers, and collars. The cable 138 is shown attached to the power drive unit 290 , by way of pulleys 292 , 294 , which is capable of providing reciprocating movement of the sliding panel back and forth across a window opening (see, for example, fixed panel opening 313 , as seen FIG. 15 ). Examples of the power drive unit 290 with pulleys 292 , 294 are units produced by Grand Rapids Controls of Grand Rapids, Mich. [0054] Although the above descriptions of FIGS. 1-13 involve a single lower right corner of the sliding assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , the same descriptions apply to a lower left corner of the sliding assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , which assemblies would reciprocally be pulled from left to right, and then be pulled from right to the left by the drive unit 290 , for opening and closing a fixed panel opening. [0055] To summarize, the powered slider panel assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 of the present invention have a sliding panel 25 , 45 , 65 , 85 , 105 , 125 , 145 , 165 , 185 , 205 , 225 , 245 , 285 that defines a window opening (like opening 313 ) and a sliding panel 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 that is movable between a closed position covering the window opening 313 and an open position, where the sliding panel has a frame member 12 , 32 , 52 , 72 , 92 , 112 , 132 , 152 , 172 , 192 , 212 , 232 , 272 , 314 secured around at least a portion of the periphery of the sliding panel, and the sliding panel along with a frame defines a plane. There is at least one guide pin 16 , 36 , 56 , 76 , 96 , 136 , 156 , 176 , 196 , 216 , 276 a - d extending substantially vertically downwardly from a portion of the frame member which is disposed on a bottom portion of the sliding panel and there is at least one cable 18 , 38 , 58 , 78 , 98 , 102 , 118 , 122 , 138 , 158 178 , 198 , 222 , 218 , 242 , 238 , 278 a - d connected at a first end to the guide pin, to the frame member, or to both, and a second end of the cable is connected to the sliding panel drive unit 290 , wherein at least the first end of the cable is in the plane of sliding panel 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , which includes the corresponding frame member. [0056] The above described sliding assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 may be operated as a vehicle window assembly that could be categorized as non-flush, flush, or flush-flush. With regard to a flush-flush vehicle window assembly, FIG. 14 shows a sliding assembly 270 with all four corners being capable of being operated as a flush-flush sliding panel assembly 270 having a frame 272 , four pins 276 a - d , two cables 278 c,d (for bidirectional control by the drive unit 290 ), and a sliding panel 285 . In addition, there are two tracks 282 , 284 that have respective paths 286 , 288 disposed within. The cables 278 c,d may be connected to the frame 272 or any of the pins 276 a - d . For the sliding panel assembly 270 , the pins 276 are required to be longer than those in the Seiple device, in order to extend through the corresponding tracks 282 , 284 . [0057] It is noteworthy that the paths 286 , 288 are different than those of Seiple, which are illustrated in Seiple's FIG. 15 as paths 328 , 329 , wherein the present invention paths 286 , 288 are connected together, while the paths 328 , 329 (with corresponding upper paths that are not shown but similar to paths 28 a , 29 a of Seiple) are separate from one another. Both sets of paths 286 , 288 and 328 , 329 , however, are capable of positioning the sliding panel assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , 270 into a flush-flush orientation. [0058] The pins 16 , 36 , 56 , 76 , 96 , 136 , 156 , 176 , 196 , 216 , with or without washers 34 , 74 , 114 , 154 , 194 , 234 , slide similarly as the various pins of Seiple. If the pins 276 a - d are longer than a thickness H′ (see FIG. 14 ) of the tracks 282 , 284 , while in the order of the dimensions H1-H4 that are illustrated in FIGS. 3-6 , 11 and 12 , then the pins 276 a,b,c,d may accommodate the washers 74 , 114 , 194 , 234 and collars 178 , 200 , 220 , 240 , thereby allowing the cables 58 , 78 , 102 , 122 , 178 , 198 , 218 , 238 to function as intended. [0059] Hence, the present invention provides powered sliding assemblies that directly and smoothly drive sliding panel assemblies having little noise. While achieving these benefits, such powered sliding assemblies are simple in design, thereby having few parts which reduce material and labor costs. The few parts being realized in the present invention is a result of directly attaching the sliding panel assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , 270 to the drive unit 290 , via the pulleys 292 , 294 . In the case of the prior art powered sliding assemblies, the cables are directly attached to a separate device like Lin's carrier block, which in turn indirectly attaches to an attachment block that is connected to a sliding panel assembly. [0060] In addition, the sliding panel assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , 270 of the present invention can be incorporated into the flush-flush track and path design of the Seiple patent. FIG. 15 of the present invention is essentially prior art FIG. 1 of Seiple, where a horizontal vehicle sliding window assembly 310 comprises two fixed panels 311 , 312 with the window opening 313 therebetween. [0061] An opening frame 314 defines the window opening 313 and upper and lower tracks 315 , 316 are disposed respectively above and below the window opening 313 . Shown in the lower track 316 are separate paths 328 , 329 that can locate the sliding panel assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , 270 of the present invention into a flush-flush position with respect to the fixed panels 311 , 312 and the vehicle body panel 144 (see FIG. 13 ). Although hidden from view, there are equivalent paths in the upper track 315 as FIG. 2 of Seiple illustrates. Consequently, the sliding panel assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , 270 of the present invention can take advantage of the prior art structure of the flush-flush horizontal vehicle sliding window assembly 310 . [0062] With the washers 34 , 74 , 114 , 154 , 194 , 234 installed on the pins 36 , 76 , 116 , 156 , 196 , 236 , as illustrated in FIGS. 2 , 4 , 6 , 8 , 10 , 12 , the sliding panel assemblies 30 , 70 , 110 , 150 , 190 , 230 can slide across the surface 289 of the track 282 and a surface 318 of the track 316 smoothly, with less resistance, and reduced noise being generated. [0063] Also, the sliding panel assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , 270 of the present invention can be incorporated into a single fixed panel assembly 400 , as shown in FIG. 16 . The single fixed panel assembly 400 has a single fixed panel 402 with a window opening 404 , where anyone of the sliding panel assemblies 10 , 30 , 50 , 70 , 90 , 110 , 130 , 150 , 170 , 190 , 210 , 230 , 270 is movable on tracks, for example, tracks 282 , 284 , 315 , 316 , between a closed position covering the window opening 404 and an open position. The single fixed panel assembly 400 cooperates with a frame member, for example, frames 12 , 32 , 52 , 72 , 92 , 112 , 132 , 212 , 232 , 272 , secured around at least a portion of the periphery of a sliding panel, for example, sliding panels 25 , 45 , 65 , 85 , 105 , 125 , 145 , 165 , 185 , 205 , 225 , 245 , 285 . [0064] In accordance with the provisions of the patent statutes, the principles and modes of operation of this invention have been described and illustrated in its preferred embodiments. However, it must be understood that the invention may be practiced otherwise than specifically explained and illustrated without departing from its spirit or scope.	A powered sliding drive assembly is provided with a sliding panel having a frame member on its periphery and guide pins that are on the bottom of the sliding panel. The pins may have a washer and/or a collar disposed on them. The washers provide quiet movement of the sliding pane. The sliding panel defines a plane. The assembly further has two or more cables, each of which is separately attached on one end to opposite sides of the frame member, pins, washers, and/or collars, where each of these ends of the cables is in the plane of the sliding panel. Each cable is attached on another end to opposite sides of a drive unit. The pins of the sliding panel are positioned in tracks, whereby the sliding panel can be located in a flush-flush position with a fixed panel and a vehicle body panel.
You are an expert at summarizing long articles. Proceed to summarize the following text: This is a divisional of the prior application Ser. No. 07/880,140, filed on May 6, 1993, U.S. Pat. No. 5,248,021 issued Sep. 28, 1993, the benefit of the filing date of which is hereby claimed under 35 U.S.C. § 120. FIELD OF THE INVENTION The present invention relates to a special bracket attachable to the understructure of a roof so as to serve as an anchor for a worker's lifeline. BACKGROUND OF THE INVENTION Government regulations often require fall prevention systems for roofers or others working on a roof. The requirements can vary depending on the pitch of the roof and the maximum slack in a lifeline that tethers the worker to an anchor member. Fall "restraint" systems may specify a prescribed minimum ratio, such as 4:1, of anchor strength to worker's weight for a prescribed amount of maximum slack in the lifeline. More stringent fall "arrest" regulations may apply for roofs of higher pitches or safety systems allowing greater freedom of movement of the worker, i.e., greater slack in the lifeline. Regulations written specifically for roofers may be equally applicable to other workers supported on the roof after the finish roofing has been installed. Glynn et al. U.S. Pat. No. 4,249,713, issued Feb. 10, 1981, discloses a specialized anchor formed of flat metal strap with long opposite end portions angled relative to each other to fit over the ridge of a roof understructure. Such angled end portion are intended to be positioned over inclined rafters at opposite sides of the ridge and have holes for nailing such opposite end portions to the rafters. The central portion of the anchor is return bent and has registered holes for a snap hook to which a lifeline can be attached. At the end of the roofing procedure, Glynn et al. proposed that the central portion of the anchor be bent over and covered by the ridge cap. Jackson U.S. Pat. No. 3,237,717, issued Mar. 1, 1966, discloses a complicated safety rigging for roofers in which opposite ends of guidelines are anchored to the ground at opposite sides of a building structure. Berry U.S. Pat. No. 742,565, issued Oct. 27, 1903, discloses a scaffold supported on an inclined roof by a "z-shaped hook" which includes one leg hooked over the ridge of the roof. Similarly, Elkins U.S. Pat. No. 677,645, issued Jul. 2, 1901, discloses a shingler's carriage suspended from special hinged hooks which are affixed to a roof at the ridge. SUMMARY OF THE INVENTION The principal object of the present invention is to provide an anchor for a safety lifeline which allows a roofer to be tethered to the anchor safely, which meets some of the more stringent government regulations, which can be installed conveniently and quickly in standard roof construction without requiting special tools or application procedures, which does not require special procedures for extraction but which preferably remains functional as a lifeline anchor after roofing has been completed, and which is sufficiently inexpensive so as to be cost effective for a variety of roofing jobs. In the preferred embodiment of the present invention, the foregoing object is accomplished by providing an anchor in the form of a bracket having parallel legs for embracing a rafter and an apertured upwardly projecting central portion for connection of a standard snap hook or carabiner to which a lifeline can be attached. The legs of the bracket preferably have preformed nail holes for convenient securing of the legs to the rafter. Larger registered holes can be provided for a bolt extending transversely through the rafter and the legs. The bottom end portions of the legs can be bent inward underneath the bottom of the rafter providing greater strength and resistance to twisting or swinging movement of the bracket relative to the rafter. Alternatively, the legs can extend downward substantially below the bottom of the rafter and have registered holes in the projecting portions of the legs for a bolt fitted close beneath the bottom of the rafter. Alternative bolt holes can be provided for rafters of different sizes and for different methods of installation of the bracket. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top perspective of a fall arrest lifeline roof anchor in accordance with the present invention; FIG. 2 is a top perspective of the anchor of FIG. 1 fitted over a roof rafter; FIG. 3 is a top perspective of the anchor of FIGS. 1 and 2 installed on a roof rafter with sheathing applied over the anchor and rafter; FIG. 4 is a vertical section along line 4--4 of FIG. 3; FIG. 5 is a top perspective of the anchor of FIGS. 1 and 2 installed on a roof rafter, showing an alternative installation of roof sheathing over the anchor and rafter; FIG. 6 is a section along line 6--6 of FIG. 5; FIG. 7 is a top perspective of the roof anchor of FIGS. 1 and 2 installed through roof sheathing and onto a rafter; FIG. 8 is a top perspective of an alternative form of fall arrest lifeline roof anchor in accordance with the present invention; FIG. 9 is a top perspective of the anchor of FIG. 8 installed on a roof rafter; FIG. 10 is an end elevation of another modified form of fall arrest lifeline roof anchor in accordance with the present invention installed on a rafter below roof sheathing, with the rafter shown in section; FIG. 11 is a top perspective of the anchor of FIG. 10 installed on a rafter subsequent to installation of the roof sheathing; FIG. 12 is a section along line 12--12 of FIG. 10 but with the anchor fitted only partway onto the rafter; FIG. 13 is a top perspective of still another modified form of fall arrest lifeline roof anchor in accordance with the present invention installed on a rafter before installation of roof sheathing over the rafter; FIG. 14 is an end elevation of the anchor of FIG. 13 illustrating installation of such anchor over roof sheathing supported on a rafter, the rafter being shown in section; and FIG. 15 is a fragmentary side elevation of yet another modified form of fall arrest lifeline roof anchor in accordance with the present invention installed on a roof rafter after installation of roof sheathing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, a fall arrest lifeline roof anchor 1 in accordance with the present invention preferably is in the form of a bracket formed of a continuous strap of strong sheet metal material such as cold rolled or heat-treated steel. The bracket strap has a return bend 2 at its center such that facing surfaces of the central portions 3 of the bracket strap are in contiguous engagement. Such central portions have registered apertures 4. The opposite end portions of the strap are bent perpendicularly outward forming shoulders 5. From such shoulders the strap ends are bent perpendicularly downward so as to form transversely spaced parallel legs 6. Preferably each leg has several small through holes 7. The anchor of FIG. 1 can be applied to a roof rafter R as shown in FIG. 2. Legs 6 are simply fitted downward over the rafter until the rafter engages against the undersides of the aligned shoulders 5. The anchor can be secured in position by nails N driven through the holes of the legs 6. A snap hook or carabiner C can be fitted in the registered apertures 4 for connection of a worker's lifeline which can extend to a suitable rope grab device worn by the worker. Preferably the upper corners of the anchor have bevels 8 so as not to interfere with swinging movement of the snap hook or carabiner relative to the central portion of the strap. With reference to FIGS. 3 and 4, after installation of the anchor 1 in the manner described above, roof sheathing can be applied over it such as by cutting a slot 10 in a sheathing sheet S and fitting the sheet downward over the anchor so as to rest on top of the anchor shoulders 5 and rafter R. Alternatively, as illustrated in FIGS. 5 and 6, the anchor can be positioned at a location of a joint between sheathing sheets S which can abut at approximately the center of the rafter R so that cutting of a slot in a sheathing sheet is not required. With reference to FIG. 7, another option is to install the anchor 1 after the sheathing has been applied. In that case, slots 11 are cut through the appropriate sheathing sheets which were previously installed on the rafter R. Legs 6 of the anchor 1 can be inserted downward through such slots 11 until the shoulders 5 of the anchor engage against the upper surface of sheet S. Nails N then can be driven through the holes in the legs and into the rafter to secure the anchor in position. Regardless of the procedure used for installing the anchor, it withstands application of greater force at the location of the registered apertures 4 than the fall restraint anchor shown in my co-pending application, Ser. No. 761,201, and therefore meets more stringent government regulations. Preferably, appropriate flashing and finish roofing F (FIG. 4) is applied around the anchor so that it becomes a permanent fixture and is usable by workers on the roof after the roofing project has been completed, in addition to being usable during application of the roofing. While the form of the invention shown in FIG. 1 installed in any of the manners described above withstands greater pull-out force than other known anchors, nevertheless, when a large force is applied in a direction parallel to the length of the rafter, a strong shearing action is transmitted to the nails through the anchor member legs as the anchor tends to swing relative to the rafter. In addition, transverse force may tend to spread the legs apart, making the anchor more susceptible to pullout. In the modified form of anchor in accordance with the present invention, shown in FIG. 8, a larger aperture 12 is provided at about the center of each leg 6. The anchor is fitted over a rafter R as illustrated in FIG. 9, and a bore is drilled through the rafter in alignment with the larger apertures. A cross member or bolt B has its shank received in such bore and the registered larger central apertures. The bolt interconnects the legs, prevents the legs from spreading apart and rigidities the installation so as to increase the pull-out force that the installed anchor will withstand. In other respects, the embodiment of FIGS. 8 and 9 is identical to the first described embodiment; and the embodiment of FIGS. 8 and 9 can be installed above roof sheathing as well as below it. In the embodiment illustrated in FIG. 10, the legs 6' of the anchor are longer and are bent perpendicularly inward at the bottom so as to be positioned close beneath the underside of the rafter R. The inward-extending portions 13 of the legs can have one or more holes for nails N driven vertically upward to secure such portions in position. Because of the engagement of such portions against the underside of the rafter, there is less tendency of transmitting sheafing force to the horizontal nails through the legs 6', and there also is less tendency of the legs to spread apart because of the vertical nails driven upward through the inward-extending portions 13. As also illustrated in FIG. 10, legs 6' can have central apertures 12 for a bolt B extending through such apertures and an aligned bore in the rafter for even greater strength. In order to install the modified anchor 1 shown in FIG. 10 before installation of the roof sheathing, it is only necessary to spread the legs 6' apart sufficiently that the legs can be fitted downward over the rafter. The natural resilience of the metal strap material causes the legs to spring back together when the inward-extending portions 13 pass beneath the underside of the rafter. The modified anchor shown in FIG. 10 also can be installed after installation of the roof sheathing, as illustrated in FIGS. 11 and 12. In that case a rectangular opening 14 must be cut in the sheet S at an area overlying the rafter (or aligned side notches in adjacent sheets in the case of a joint falling on the rafter) such that the anchor legs 6' will fit through the opening 14 as illustrated in FIG. 12. In the form of anchor in accordance with the present invention shown in FIG. 13, the legs 6" are of a length sufficient to extend downward below the bottom of the rafter R but are not bent inward. Rather, registered apertures are provided for a cross member or bolt B to extend close beneath the rafter so as to act similarly to the inturned end portions of the embodiment shown in FIG. 10. One or two bolts can be used so as to reduce the tendency of the anchor to tilt and apply shearing force on the nails N as force is applied in a direction generally parallel to the length of the rafter. The lower hole 15 in FIG. 13 is at the proper location for registered holes for an installation of the type illustrated in FIG. 14 where the anchor is installed over the roof sheathing S. In that manner of installation, there is a greater distance from the aligned anchor shoulders 5 to the underside of the rafter R than if the anchor is installed directly to the rafter before application of the sheathing. FIG. 15 illustrates another modified form of anchor in accordance with the present invention. Each leg 6"' has three pairs of bolt apertures for rafters of different depths. The upper pair is positioned to be used with 2×4 rafters stood on end, the upper hole 16 being appropriate for a bolt to extend close beneath the rafter if the anchor is applied directly over the rafter and the lower hole 17 being appropriate for a bolt to extend close beneath the rafter if the anchor is applied over the roof sheathing. The middle pair of holes is positioned so as to be appropriate for a 2×6 rafter stood on end, the upper hole 18 being appropriate if the anchor is applied directly over the rafter and the bottom hole receiving bolt B being appropriate if the anchor member is applied over the roof sheathing as illustrated in FIG. 15. Similarly, the bottom pair of holes 19 and 20 is designed for 2×8 rafters stood on end. For each installation, a bolt extends close beneath the rafter and interconnects the spaced-apart legs to increase resistance to pullout.	A bracket has downwardly-projecting parallel legs for embracing and being secured to opposite sides of a rafter and an upwardly-projecting central portion having an aperture for connection of a standard snaphook or carabiner to which a lifeline can be attached. The legs of the bracket can be interconnected by a bolt extending through or below the rafter. In addition or alternatively, the bottom end portions of the legs can be bent inward underneath the bottom of the rafter. The bracket is used in a fall prevention safety system in which the lifeline tethers a roofer or other worker to the anchor.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION [0001] The field of the invention relates to a curtain that forms a seal with the frame of an opening such as a window or door as the curtain is urged across that opening. The curtain is durable so that it is able to withstand substantial external pressure without breakage. BACKGROUND OF THE INVENTION [0002] The use of sealed curtains is known in the prior art. Generally, a sealed curtain apparatus comprises a curtain and tracks along the frame of an opening such as a door or window. The edges of the curtain are engaged by the tracks. As the curtain is moved towards a position covering the opening, the edges of the curtain travel along the tracks. The benefit of this design is that the sealed curtain prevents matter such as insects and debris from passing through the space between the curtain and the frame. However, because the curtain is sealed, the apparatus becomes less durable because it cannot yield to external forces. With unsealed curtains, an external force applied to the curtain will merely briefly displace the curtain from the door or window frame. With sealed curtains, the engagement of the curtain edges with the tracks on the frame prevents the curtain from becoming displaced. Consequently, an external force applied to the sealed curtain may cause stress on the curtain leading to breakage. [0003] In this respect, the durable sealing curtain according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus which provides a seal between the edges of a curtain and the frame of an opening such as a door or window that is better able to withstand the application of substantial external forces without suffering failure of the apparatus. [0004] Furthermore, in the prior art, the more tautly a sealed curtain is pulled across an opening, the more difficult it generally is to slide the curtain along the tracks. In this respect, the durable sealing curtain according to the present invention allows the curtain to be loosened while urged open or shut and then returned to a taut position when the curtain is in place. SUMMARY OF THE INVENTION [0005] In view of the foregoing disadvantages inherent in the known types of sealed curtains present in the prior art, the present invention provides an improved apparatus wherein the same is able to withstand the application of substantial external forces without suffering failure of the apparatus and provides a more easily slidable curtain that is still taut when the curtain is in place. [0006] To attain this, the preferred embodiment of the present invention is a sealed curtain which preferably comprises a pair of tracks slidably attached to opposite sides of an opening such as a door or window, a curtain having edges engaged by the tracks, and spring systems attached to each track, whereby the spring systems urge the tracks outwardly to maintain the curtain taut yet allow the tracks to slide inwardly towards the center of the opening so that the curtain does not endure excessive pressure upon application of an external force. At least one track preferably also includes a cam mechanism that is operative to urge the track inwardly to decrease tension on the curtain and thereby allow the curtain to be more easily raised or lowered, after which, the cam mechanism can be disengaged to allow the track to return to its outwardly biased position, thus returning the curtain to a taut condition. BRIEF DESCRIPTION OF THE DRAWINGS [0007] The invention will be better understood when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: [0008] FIG. 1 is a perspective view of the preferred embodiment of the present invention. [0009] FIG. 2 is a sectional view of the preferred embodiment taken along line 2 - 2 of FIG. 1 . [0010] FIG. 3 is the sectional view of FIG. 2 with the curtain displaced away from the plane of the opening by an external force in the direction of the arrows. [0011] FIG. 4 is a sectional view of an alternate embodiment of the present invention comprising tracks on each side of the opening designed for holding two curtains. [0012] FIG. 5 is a detailed view of an alternate embodiment of the present invention showing a cam mechanism disengaged from the track to keep the curtain taut. [0013] FIG. 6 is a detailed view of the embodiment of FIG. 5 showing the cam mechanism engaging the track to release tension from the curtain. [0014] FIG. 7 is an exploded perspective view of the embodiment of FIG. 5 . [0015] FIG. 8 is a perspective view of an alternate track comprising a diagonally-shaped slot. [0016] FIG. 9 is a perspective view of an alternate embodiment of the present invention comprising a rod attached to each track for engaging the edge of the curtain. [0017] FIG. 10A is a sectional view of the embodiment of FIG. 9 taken along line 10 - 10 of FIG. 9 . [0018] FIG. 10B is a sectional view of an alternate embodiment of the invention of FIG. 10A showing each hem of a multi-layered curtain located on the side of the rod opposite the opening. [0019] FIG. 11 is a perspective view of an alternate embodiment of the present invention designed for horizontal movement of the curtain across a door frame. [0020] FIG. 12 is a sectional view of the embodiment of FIG. 11 taken along line 12 - 12 of FIG. 11 . [0021] FIG. 13 is a sectional view of an alternate embodiment of the invention of FIG. 1I comprising sloped floor tracks above the floor plane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0022] The curtain apparatus is indicated generally by the numeral 10 . The curtain apparatus 10 is designed to be attached to the frame of an opening 4 such as a door or window. However, the invention does not require the use of a pre-existing frame and could be practiced whereby the invention is incorporated into a prefabricated frame. The curtain apparatus 10 has a first track 1 and a second track 2 . The first track 1 is slidably attached to a first frame member 5 of the opening 4 . The second track 2 is slidably attached to a second frame member 6 of the opening 4 . The curtain apparatus 10 has a curtain 7 . The lateral edges 11 of the curtain 7 and the lateral edges 12 of the tracks 1 , 2 are each shaped to allow the curtain edges to be engaged by the lateral edges of the tracks. This engagement is preferably accomplished with U-shaped or V-shaped curtain edges 11 and track edges 12 . Where the curtain edges 11 are V-shaped, the apex of the curtain edges 11 are preferably heat sealed or hemmed. However, what is important is that the curtain edges 11 and track edges 12 are sufficiently engaged to prevent the curtain 7 from detaching from either track 1 , 2 . The curtain edges 11 are of sufficient rigidity so that they remain engaged by the track edges 12 . The engagement of the curtain edges 11 by the track edges 12 allow the curtain 7 to be slidably engaged by the tracks 1 , 2 so that the curtain 7 may be positioned at any location along the opening 4 . The U-shaped or V-shaped fold in the curtain edges 11 remains present when the curtain 7 is rolled. [0023] At any given position, the portion of the curtain 7 not covering the opening 4 is wound around a rotatable shaft 51 . As the curtain 7 is urged to cover the opening 4 , the shaft 51 rotates to unwind the curtain 7 . As the curtain 7 is urged to uncover the opening 4 , the shaft 51 rotates in an opposite direction to wind the curtain 7 around the shaft 51 . Rotation of the shaft 51 is preferably controlled by a driving mechanism 53 , which is preferably motorized. However, the driving mechanism 53 may be manually operated and also may include a counter spring. A bracket 54 is attached to each frame member 5 , 6 to support the shaft 51 . The curtain 7 has a leading edge 55 that preferably has a weighted member 56 hemmed therein. [0024] In an alternate embodiment shown in FIGS. 9 and 10 A, the tracks 1 , 2 each have a rod 40 attached thereto. In this embodiment, each track 1 , 2 preferably has an extension 43 at one end and a guide 44 at the opposite end. The lower end of the rod 40 is preferably fixedly attached to the rod extension 43 . The rod guide 44 has an opening therethrough for receiving the upper end of the rod 40 . Each lateral edge of the curtain 7 has a hem 41 forming an elongated channel 42 for slidably receiving a rod 40 . In an alternate embodiment, the curtain may be multi-layered with a single channel along each lateral edge. The use of a multi-layered curtain allows air to become trapped between the layers so that the apparatus 10 may provide greater insulation. As best shown in FIG. 10B , this multi-layered curtain design may also be practiced whereby each hem 41 is located on the side of a rod 40 opposite the opening 4 . Similarly, this design may also be practiced without hems 41 whereby the multi-layered curtain is comprised of a continuous material surrounding both rods 40 . [0025] Each track 1 , 2 preferably has two spring mechanisms 8 that bias the track away from the opening 4 , thereby keeping the curtain 7 taut. The spring mechanisms 8 allow the tracks 1 , 2 to move inwardly towards the opening 4 in the event an external force is applied to the curtain 7 , thus reducing the possibility of damage to the curtain 7 . The spring mechanisms are preferably placed near the opposite ends of each track 1 , 2 . Each spring mechanism 8 preferably comprises a first post 13 and a second post 14 , each fixedly attached to a track 1 , 2 . The first and second posts 13 , 14 are preferably screws. The first post 13 and second post 14 are preferably positioned in such a manner whereby a line intersecting both posts 13 , 14 would be substantially parallel to the line dividing the frame members 5 , 6 and the opening 4 . Approximately equidistant from the first post 13 and the second post 14 is a connecting member 15 that connects the tracks 1 , 2 to the frame members 5 , 6 . The connecting member 15 is preferably on the opposite side of the line intersecting the first post 13 and the second post 14 from the opening 4 . A horizontal slot 16 is cut into each track through which the connecting member 15 passes. The slot 16 allows the tracks 1 , 2 to move relative to the connecting member 15 and thus relative to the frame members 5 , 6 . Consequently, when an external force is applied to the curtain 7 , the slot 16 allows the tracks 1 , 2 and curtain edges 11 to move inwardly so that the external force is not as likely to damage the curtain 7 or the seal of the edges 11 . A spring 17 is preferably attached at its first end to the first post 13 and at its second end to the second post 14 , therebetween engaging the connecting member 15 to bias the tracks 1 , 2 away from the opening 4 . The spring 17 can be a coil or any flexible, resilient member. [0026] With no external forces applied to the apparatus, the first track 1 abuts the first frame member 5 and the second track 2 abuts the second frame member 6 . As best shown in FIGS. 2-3 , both tracks 1 , 2 are on the same side of their respective frames 5 , 6 , referred to as the track side 30 of the apparatus 10 . The opposite side of the apparatus 10 is the non-track side 31 . As best shown in FIG. 3 , if an external force is applied originating from the non-track side 31 , then the edges of the track 12 are not only able to slide inwardly towards the opening 4 , but are also able to separate from the frame and move in the direction of the force. This movement allows even less stress to be borne by the curtain 7 and thus less chance that the curtain 7 will fail. Preferably, the tracks 1 , 2 are on the inside of the building whose door or windows are sought to be covered by the curtain 7 of the present invention, thus lessening the opportunity for the apparatus 10 to be vandalized or disabled by individuals outside of the building. In this design, external forces such as wind would always originate from the non-track side 31 . While the apparatus is still able to withstand forces originating from the track side 30 , the ability of the track edges 12 to separate from the frame members 5 , 6 allows the apparatus to withstand even greater forces originating from the non-track side 31 . So that the track edges 12 may separate from the frame members 5 , 6 , the connecting member 15 is preferably a bolt where the head of the bolt prevents the tracks 1 , 2 from completely detaching from the frame members 5 , 6 , but is not completely tightened to maintain the tracks 1 , 2 flush with the frame members 5 , 6 , thereby allowing the tracks 1 , 2 to move in the plane perpendicular to the plane of the opening 4 . While such positioning of the connecting member 15 allows the track edges 12 to separate from the frame members 5 , 6 upon the application of an external force, it is preferable that, in the absence of such a force, the track edges 12 abut the frame members 5 , 6 . Thus, as best shown in FIGS. 2-3 , a compression spring 101 and a washer 102 are preferably located between the head of each connecting member 15 and its corresponding tracks 1 , 2 . The tension of the compression springs 101 are preferably weak enough to permit the track edges 12 to separate from the frame members 5 , 6 upon the application to the apparatus 10 of an external force, yet strong enough to urge the track edges 12 to return to their original positions abutting the frame members 5 , 6 upon the termination of such external force. [0027] In an alternate embodiment shown in FIG. 4 , the present invention has a track on both the first frame 5 and the second frame 6 , wherein each track has at least two slightly offset substantially U-shaped track edges 12 for receiving the edges of a plurality of curtains 7 . Consequently, this embodiment allows for at least two curtains 7 to be pulled across the same opening 4 . Most preferably, the curtains 7 in this embodiment would be made of different materials, such as where one curtain 7 is made of mesh to allow some visibility and the other curtain 7 is opaque. Since the curtains 7 are on different track edges 12 , this embodiment allows the user to close either curtain 7 , for example the mesh or opaque curtain 7 as he or she desires. [0028] In the embodiment of the invention shown in FIGS. 5-7 , the apparatus 10 has a cam plate 20 . While the apparatus 10 could have a cam plate 20 on each track 1 , 2 of the apparatus 10 , the cam plate 20 is preferably on only one track of the apparatus 10 , the description herein showing the cam plate mounted adjacent track 2 . The cam plate 20 abuts at least one fixed member, in this case connecting member 15 performs the function of the fixed member, and at least one mobile member, in this case fixed post 14 performs the function of the mobile member. The fixed member 15 is attached to the frame member 6 and the mobile member 14 is attached to the track 2 . The cam plate 20 has a diagonal cam surface 23 in abutment with fixed member 15 . [0029] When the cam plate 20 is activated by being urged along the track 2 , the cam surface 23 engages the fixed member 15 , thereby urging the cam plate 20 towards the opening 4 . Since the cam plate 20 abuts mobile member 14 , the urging of the cam plate 20 towards the opening 4 also causes the mobile member 14 to be urged towards the opening 4 . Since the mobile member 14 is attached to the track 2 , the result of the activation of the cam plate 20 is that the track 2 is urged toward the opening 4 . The urging of the track 2 towards the opening 4 decreases tension on the curtain 7 . Consequently, the curtain 7 is less taut and is easier to slide open or closed when the cam plate 20 has been engaged. While the cam plate 20 may be engaged through the manual manipulation of a lever 26 , this embodiment may also be practiced by using an automated device where, for example, the cam plate 20 is activated while the curtain 7 is being opened or closed. Once the curtain 7 reaches a predetermined setting, a sensor detects this positioning and the cam plate 20 is disengaged and the curtain 7 is pulled taut. The cam plate 20 preferably has a securing notch 50 adjacent to the cam surface 23 . When the cam plate 20 is activated by being urged along the track 2 , cam surface 23 slides along fixed member 15 until fixed member 15 is positioned within the securing notch 50 , best shown in FIG. 5 , thereby securing the cam plate 20 as shown in FIG. 6 . [0030] While the preferred embodiment accomplishes the aforementioned camming action through a track 2 having an abutting cam plate 20 , another embodiment shown in FIG. 8 achieves a similar action without the use of a cam plate 20 . In this embodiment, the slot 21 is angled upwardly and inwardly towards the opening 4 . While such features may be present, this embodiment does not require a spring assembly 8 . This embodiment requires at least one fixed member 22 located within the slot 21 . The diagonally-shaped slot 21 described above creates the cam surface 23 described in other embodiments of this invention. A lower shelf 26 is formed on the bottom of the track 2 and is preferably substantially perpendicular to the track 2 . Using this construct, the track 2 may be urged upwardly and inwardly towards the opening 4 , causing the curtain 7 to be loosened while it is urged in either direction along the track. When the curtain 7 is lowered, the leading edge 55 will engage shelf 26 and force shelf 26 in a downward direction. Since the shelf 26 is connected to the track 2 , the track 2 is thus urged downwardly and outwardly from the opening 4 , thus tensioning the curtain 7 . [0031] While the most common embodiment of the invention is where the curtain 7 is urged upwardly and downwardly over an opening 4 such as a door or window, FIGS. 11-13 show alternate embodiments where the curtain 7 is urged sideways over an opening 4 such as a patio door. In these embodiments, the features are substantially the same, but rotated ninety degrees. For example, the first 1 and second tracks 2 are upper and lower tracks rather than left and right tracks as in the most common embodiment. However, the lower track will be referred to as the floor track 25 and the lower frame member as the floor frame member 24 . The first embodiment of this design, as shown in FIG. 12 , has a floor track 25 below the plane separating the floor frame member 24 from the opening 4 . The second embodiment of this design, as shown in FIG. 13 , has a floor track 25 mounted on top of the floor frame 24 . In this embodiment, the floor track 25 has a ramped front end 27 and back end 28 . The upper surface of the floor track 25 is substantially horizontal. The angle of the ramped front end 27 and back end 28 is preferably less than or equal to 45°, more preferably less than or equal to 35°, and even more preferably less than or equal to 25°. This allows the opening 4 to be traversed with reduced risk of serious injury from tripping over the floor track 25 due to the gentle sloping nature of the floor track 25 . [0032] It is to be understood that the forms of the invention shown and described are preferred embodiments thereof and that various changes and modifications may be made therein without departing from the spirit of the invention or scope as defined in the following claims.	A durable sealing curtain assembly preferably comprising a pair of tracks slidably attached to opposite sides of an opening such as a door or window, a curtain having its lateral edges engaged by the tracks, and spring systems attached to each track, whereby the spring systems urge the tracks outwardly to maintain the curtain taut yet allow the tracks to slide inwardly towards the center of the opening so that the curtain does not endure excessive pressure upon application of an external force. At least one track preferably also comprises a cam mechanism that is operative to urge the track inwardly to release tension from the curtain and thereby allow the curtain to be more easily raised or lowered, after which, the cam mechanism can be disengaged to allow the track to return to its outwardly biased position, thus returning the curtain to a taut condition.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION The present invention relates to improvements in a method for constructing a tunnel. The inventor of this invention proposed, in Japanese Patent Publication No. 54-33656, a method for constructing a tunnel consisting of the steps of assembling an inner form within a tunnel bore that has been successively dug by means of a shield tunnelling machine, placing concrete in a space delimited by the form, a shield tail and a front surface of an already placed concrete lining, and thereafter shoving the shield tunnelling machine by means of a concrete lining jack and a shield jack equipped on the shield tunnelling machine with shoving reaction forces received by the placed concrete and the inner form. In soft ground to which a shield tunnelling method is applied for constructing a tunnel, it is necessary to employ a reinforced concrete structure to assure safety of the tunnel body structure. Accordingly, upon practicing the above-mentioned constructing method in the prior art, it is necessary to set a reinforcing steel cage within the shield tail of the shield tunnelling machine and to dispose it at a predetermined position. However, in the shield tail section, working space is very narrow, so the work for assembling the reinforcing steel cage becomes complex, and moreover it is difficult to dispose the set reinforcing steel cage at a predetermined position. Furthermore, upon compressing the placed concrete, there is a fear that the reinforcing steel cage may be moved or deformed. Therefore, it becomes impossible to realize the function of a desired reinforced concrete structure. SUMMARY OF THE INVENTION It is therefore one object of the present invention to provide an improved method for constructing a tunnel in which a main tunnel body can be constructed easily and correctly as a reinforced concrete structure through a shield tunnelling method of a field-placed concrete lining type. According to one feature of the present invention, there is provided a method for constructing a tunnel, in which a reinforcing steel cage is mounted to a combined spreader and end form of a concrete lining jack via metal mounts, placed concrete for lining is compressed while the reinforcing steel cage is moved, and thereby the reinforcing steel cage is disposed at a predetermined position within the concrete for lining. Upon practicing the present invention as featured above, a spreader of a concrete lining jack equipped to a shield tunnelling machine is commonly used as an end form of concrete lining, a preliminarily assembled reinforcing steel cage is mounted to the combined spreader and end form via mount metals, and by extending the concrete lining jack the reinforcing steel cage is moved to the side of concrete for lining which has been placed in the spaced delimited by an inner form assembled within a tunnel bore that has been successively dug by means of a shield tunnelling machine, a shield tail and an already placed concrete lining, the same concrete is compressed by the combined spreader and end form, and the reinforcing steel cage is disposed at a predetermined position within the concrete for lining by adjusting the stroke of the concrete lining jack, whereby a main tunnel body can be constructed as a reinforced concrete structure through a shield tunnelling method of field-placed concrete lining type. The above-mentioned and other objects, features and advantages of the present invention will become more apparent by reference to the following description of preferred embodiments of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: FIGS. 1 through 5 are longitudinal cross-section side views showing successive steps in a method for constructing a tunnel according to one preferred embodiment of the present invention; FIGS. 6 through 12 are detailed partial views showing the same respective steps; FIGS. 13 to 16 are partial perspective views showing the steps of mounting and moving a reinforcing steel cage; FIGS. 17 and 18 are perspective views respectively showing a mount portion of a reinforcing steel cage to a concrete lining jack; FIG. 19 is a transverse cross-section front view showing a state of arrangement of isolated reinforcing steels; and FIGS. 20 through 25 are longitudinal cross-section side views showing successive steps in a method for constructing a tunnel according to another preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Now description will be made of the illustrated embodiments of the present invention. In FIG. 1, reference numeral (1) designates a shield shell in a shield tunnelling machine, numeral (2) designates a cutter, numeral (3) designates a motor for driving the cutter (2), numeral (4) designates a bulkhead, numeral (5) designates a cutter chamber formed between the bulkhead (4) and the cutter (2), numeral (6) designates a ring girder, numerals (7) and (8) respectively designate a shield jack and a concrete lining jack mounted to the ring girder (6), numeral (9) designates a shield tail section, and numeral (10) designates a concrete lining that was placed between a form assembled within a tunnel bore successively dug by the shield tunnelling machine (1) and the ground. FIG. 1 shows the state where shoving of the shield tunnelling machine has been completed by means of the shield jack (7) and the concrete lining jack (8) with the shoving reaction forces received by an inner form (11) and the concrete lining (10). FIGS. 2 to 4 show the states where the respective jacks (7) and (8) are retracted, and in this state, hook bolts (12) disposed as penetrating through a combined spreader and end form (8a) of the concrete lining jack (8) are left on the side of the concrete lining (10). Subsequently, as shown in FIG. 3, a reinforcing steel cage (13) is mounted to the combined spreader and end form (8a) via the hook bolts (12), then the reinforcing steel cage (13) is moved up to a predetermined position by extending the concrete lining jack (8), and the inner form (11) is assembled inside of the reinforcing steel cage (13) FIGS. 4 and 5 show the states where the concrete is placed in the tail section (10), and the shield tunnelling machine is shoved by jacks (7) and (8) respectively. FIGS. 6 to 10 show the steps of mounting and moving the above-mentioned reinforcing steel cage (13), in which hook bolts (12) are inserted into through-holes (14) in the combined spreader and end form (8a) (See FIG. 7), the nuts (15) are threadedly engaged with the hook bolts (12) and fastened fixedly to secure the hook bolts (12) to the combined spreader and end form (8a), and the reinforcing steel cage (13) is engaged with hook portions at the tip ends of the hook bolts (12) (See FIG. 8). Subsequently the reinforcing steel cage (13) is moved by extending the above-described concrete lining jack (8), then the tip end of the moved reinforcing steel cage (13) is engaged with hook bolts (12) projecting from a reinforcing steel cage (13) disposed in the already placed concrete lining (See FIG. 9), and thereafter an inner form (11) is assembled (See FIG. 10). Next, as shown in FIGS. 4 and 11, a concrete lining (10) is placed around the outer circumference of the newly assembled inner form (11). Subsequently, as shown in FIGS. 5 and 12, the shield jack (7) and the concrete lining jack (8) are extended with the reaction forces received respectively by the inner form (11) and the placed concrete lining (10), and thereby the shield tunnelling machine is shoved until the state shown in FIG. 1 is again established. At this time, a cavity portion (16) formed by the advance of the shield shell (1) is filled with concrete for lining (10), and the reinforcing steel cage moves rightwards as shown at (13') in FIG. 12 simultaneously with extension of the concrete lining jack (8). During this movement, the reinforcing steel cage (13') would not be displaced in the lateral position because it moves as guided by the hook bolts (12). In addition, as the reinforcing steel cage (13') is fixedly secured to the combined spreader and end form (8a) via the hook bolts (12), it would not be subjected to a thrust of the concrete lining jack (8), and hence stress or deformation would not be generated in the reinforcing steel cage (13'). When the shoving of the shield tunnelling machine has been completed in the above-described manner, the nuts (15) are removed and the combined spreader and end form (8a) is retracted, the hook bolts (12) would remain on the side of the concrete lining (10) and the state shown in FIG. 6 is realized. Thereafter, similar steps to the above-described ones are repeated and the reinforcing steel cage is buried in the concrete lining. FIGS. 13 to 16 show details of the steps of mounting a reinforcing steel cage (13) to the above-described combined spreader and end form (8a) and shoving the same. In the combined spreader and end form (8a) formed in an arcuated shape and having a large number of through-holes (14) as shown in FIG. 13, hook bolts (12) are inserted into the respective through-holes (14) (See FIG. 14), then a reinforcing steel cage (13) is engaged with the hook bolts (12) as shown in FIG. 15, and as shown in FIG. 16 the reinforcing steel cage (13) is supported by hook bolts (12) projecting from a concrete lining (10) by extending the concrete lining jack (8). FIG. 17 shows details of the mount portion of the reinforcing steel cage (13) to the hook bolts (12), a combined spacer and packing (17) is fitted around each hook bolt (12), and thereby leakage of cement paste can be prevented. FIG. 18 shows another example of the mount portion in which a packing (18) is fitted around the hook bolt (12) and a spacer (19) is interposed between the combined spreader and end form (8a) and the reinforcing steel cage (13). FIG. 19 shows the state of arrangement of reinforcing steel cages (13) each consisting of a single reinforcing bar as arranged so as to conform to the state of stresses in a transverse cross-section. More particularly, in the top and bottom portions of a main tunnel body tensile stresses would occur in an inside portion of a transverse cross-section of the concrete lining (10), whereas in the left and right portions of the main tunnel body tensile stresses would occur in an outside portion of the transverse cross-section, and therefore, the reinforcing bars are arranged so as to effectively reinforce the concrete lining against the respective stresses. FIGS. 20 to 25 illustrate another preferred embodiment of the present invention, in which a shield shell 1 includes a front shield drum (1A) and a rear shield drum (1B), and component parts equivalent to those of the above-described first preferred embodiment are given like reference numerals. FIG. 20 shows the state where shoving of the shield tunnelling machine has been completed, and starting from this state a shield jack (7) is extended with a reaction force received by an inner form (11) to make the front shield drum (1A) advance resulting in the state shown in FIG. 21. During this period, a concrete lining jack (8) extend in synchronism with the shield jack (7) and thereby holds a predetermined compressing force to a concrete lining (10). Subsequently, the respective jacks (7) and (8) are retracted, and the hook bolts (12) take the state of projecting from the reinforcing steel cage (13) within the concrete lining (10) into the space in front of the concrete surface of the concrete lining (10) (See FIG. 22). Then, a reinforcing steel cage (13) is mounted to a combined spreader and end form (8a) of the concrete lining jack (8) via hook bolts (12) and an additional inner form (11) is assembled (See FIG. 23), and further, as shown in FIG. 24, concrete for lining (10) is placed. Thereafter, as shown in FIG. 25, while the concrete for lining (10) is being compressed by the concrete lining jack (8), the rear shield drum (1B) is shoved by the reaction force of the concrete lining jack (8), and thus shoving of the tunnelling machine is completed, resulting in the state shown in FIG. 20. Subsequently, by repeating the same steps as those described above, the reinforcing steel cage is buried in the concrete lining. According to the present invention, in a shield tunnelling method of field placed concrete lining type, a main tunnel body can be constructed as a reinforced concrete structure that is structurally reliable as described above, and in this method since it is only necessary to mount a preliminarily assembled reinforcing steel cage to a combined spreader and end form of a concrete lining jack via mount metals, the work of disposing a reinforcing steel cage can be achieved easily even in a narrow space within a shield tail, and if the working space is yet insufficient, it is only necessary to retract the concrete lining jack by a desired length. Furthermore, upon disposing the reinforcing steel cage within the concrete for lining, the reinforcing steel cage can be disposed at a predetermined position in the axial direction of the tunnel by adjusting the stroke of the concrete lining jack. Still further, since the reinforcing steel cage can be assembled independently of the inner form as guided by the combined spreader and end form of the concrete lining jack within the shield tail, the form of the reinforcing steel cage is restricted by the method of assembling the inner form. While a principle of the present invention has been described above in connection to preferred embodiments of the invention, it is a matter of course that many apparently widely different embodiments thereof can be made without departing from the spirit of the present invention.	The known method for constructing a tunnel of the type in which a shield tunnelling machine is shoved by means of a concrete lining jack and a shield jack equipped on the shield tunnelling machine with reaction forces received by concrete for lining placed in a space delimited by an inner form assembled within a tunnel bore successively dug by the shield tunnelling machine, a shield tail and an already placed concrete lining, as well as by the inner form, is improved in order to construct a main tunnel body as a reinforced concrete structure. The improvements include in that a reinforcing steel cage is mounted to a combined spreader and end form of the concrete lining jack via metal mounts, the placed concrete for lining is compressed while the reinforcing steel cage is moved, and thereby the reinforcing steel cage is disposed at a predetermined position within the concrete for lining by adjusting the stroke of the concrete lining jack.
You are an expert at summarizing long articles. Proceed to summarize the following text: This is a continuation-in-part of my U.S. application Ser. No. 08/770,111 filed Dec. 20, 1996, which is a continuation-in-part of U.S. application Ser. No. 07/915,315, filed on Jul. 20, 1992, now abandoned. BACKGROUND OF THE INVENTION This invention deals generally with stock material, and more specifically with filled hollow structures such as light poles, fence posts and pilings constructed of plastic or fiberglass. The benefits of plastic and fiberglass for articles which are used where they are subject to corrosion are generally well recognized. Structures using such materials are light weight, strong and attractive. They can be made with color integrated into the material so that they do not need frequent painting during. their use, and possibly their greatest asset is the inherent chemical resistance of the material. A fiberglass or plastic structure such as a fence post can be expected to last as long as anyone wants it to, even in the most severe environment, with no sign of deterioration, and it will not require any maintenance. Unfortunately, the major limitation on the availability of such pole type fiberglass or plastic structures has been the cost and difficulty involved in their manufacture. One typical method of fiberglass construction is the forming of the fiberglass into a specific shape by wrapping multiple layers of fiberglass fabric on the outside of a core and impregnating the fabric with resin or epoxy, however such manufacturing methods are very expensive because they involve a great deal of hand labor. Another approach, particularly to the construction of cylindrical structures, is to use preformed fiberglass or plastic pipe. However, such pole structures are not strong enough for most applications unless the pipe is very thick or the structure includes wood or metal reinforcing, and both of these approaches raise the cost of fiberglass and plastic poles so that they are not competitive with conventional metal poles. One approach to reinforcing fiberglass or plastic pipe so it can be used as a structural member has been the use of fillers which are poured into the inside of the pipe, and then harden into a core. Fillers have been suggested which include wood with an adhesive binder (U.S. Pat. No. 4,602,765 by Loper) and rigid foam or concrete (U.S. Pat. No. 3,957,250 by Murphy), but these approaches do not furnish strength comparable to metal poles. Accordingly, there is a need to provide a fiber reinforced pole filled with a cementitious material to provide a piling having strengths similar to that of a steel piling and having surface features which create skin friction as the piling is driven into the ground, to increase bearing load capability of the pole. SUMMARY OF THE INVENTION An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this object is attained by providing a filled structure characterized by the combination of high compressive and tensile strength to allow a high bending load. The filled structure includes a fiber reinforced resinous hollow structure having a tensile strength of at least 30,000 psi. The hollow structure has first and second ends, an inside surface forming a boundary which encloses a space, and an outside surface. At least a portion of the outside surface of one of the ends has a roughened portion sufficient to provide increased frictional resistance with the ground when the one end is driven into the ground. A hard core is disposed within the space enclosed by the hollow structure. The hard core has a density of at least 35 pounds per cubic foot and a compressive strength of at least 1500 psi. The hard core is formed from a mixture of particulate cementitious material and liquid. Other objects, features and characteristics of the present invention, as well as the methods of operation and functional of the related elements of the structure, the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of the specification. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an end view across the axis of an embodiment of the invention. FIG. 2 is an end view across the axis of another embodiment of the invention. FIG. 3 is an end view across the axis of yet another embodiment of the invention. FIG. 4a is a partial end view of concave ridges formed in a pole of the invention. FIG. 4b is a partial end view of convex ridges formed in a pole of the invention. FIG. 5a is a front view of a lower portion of another embodiment of the invention showing an abrasive adhesive coating thereon. FIG. 5b is a front view of a lower portion of another embodiment of the invention, showing fiber rovings wrapped so as to extend from an outer surface thereof. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows an end view across the axis of pole 10 of an embodiment of the invention. Pole 10 is preferably formed of four distinct materials, one of which, core 12, takes on a particular significance because of the manner in which it is formed. Core 12 is encased within pipe 14 which is covered by veil 16, on top of which is placed protective surface coating 18. Each of the four parts of composite pole structure 10 adds a particular characteristic to the pole structure, and together they furnish a pole of superior strength and durability which can be produced economically. In the broadest aspect of the invention, the veil 16 and coating 18 need not be provided. The construction of pole 10 is essentially based upon the filling of pipe 14 with core 12, but core 12 has unique properties which produce a non-metallic pole with strength equivalent to that of steel poles. Core 12 is a Portland cement based product with admixtures which enables the mixture to expand as it hardens, or at least limit shrinkage of the mixture as it hardens. In one embodiment of the invention, it is important that the core material normally expand in order that it have a permanent positive stress and produce a force fit with exterior pipe 14. It is also vital that the hardened core have significant strength, which is best indicated by a compressive strength rating of at least 1500 psi, so that it adds significant strength to the structure and does not act to merely fill the interior space of the pipe. The load/force developed as the core 12 hardens must, however, be less than the structural strength of pipe 14 in order to prevent the forces produced by the attempted expansion during hardening of core 12 from distorting and/or substantially weakening pipe 14 as it restrains the expansion of core 12. In a preferred embodiment, cylindrical pipe 14 has a two inch outer diameter with 0.030 inch wall thickness up to a ninety-six inch diameter with at least 0.500 inch wall thickness. The pipe 14 is constructed with a standard polyester, epoxy or vinyl ester resin base, reinforced with fibrous roving, chop, or woven mat throughout its entire thickness. Such a material has a tensile strength of at least 30,000 psi. Added bending strength can be attained if the significant portion of the fibrous roving are oriented to be at an angle of at least 45 degrees to the axis of the pole or oriented generally along the axis of the pole. The fibrous rovings in the illustrated embodiment is fiberglass. It can be appreciated that other fibrous rovings such as carbon, etc. may be used. As with all fiberglass and resin structures, color pigments may be added during manufacture of pipe 14 to produce consistent color throughout the entire pipe. It is also advantageous to produce veil 16 on the exterior surface of pipe 14 when it is being manufactured. Veil 16 is a layer of polyester or other material cloth impregnated with resin. The production of such a veil is well understood by those skilled in the art of fiberglass construction. Veil 16 protects the fiberglass against ultraviolet radiation, provides a moisture barrier, protects against blooming of the surface fibers of the fiberglass and also adds strength to pole 10. The core 12 is composed primarily of a mixture of stone, sand, water, and Portland-type cement. In one embodiment of the invention, the specific material used is Type I Portland-type cement as manufactured by the Lehigh Cement Co. The stone component could be solid limestone, as commonly found at may local quarries, or lightweight type aggregate as produced, for example, by Solite Corp. The sand component is clean washed and specifically graded round silica material as is available from many local sand quarries. Normal potable water is used and other cementitious products may be employed to promote expansion or at least limit shrinkage of the core upon hardening. For example, expansion additives such as INTRAPLAST N manufactured by Sika (plastic state expansion), or CONEX, as manufactured by IM Cement Co. (early hardened state expansion) may be used in the core. Alternatively, a standard expansion agent such as alumina hydrate may be employed in the core, or the core may comprise Type K cement. When hardened this formula yields a compressive strength of 1500-15,000 psi. Moreover, one particular formula normally expands about 0.1-10 percent upon hardening, except that it is restrained by the hollow tube 14 and therefore provides an exceptionally strong force fit with hollow tube or pipe 14. The density of such a core is at least 35 pounds per cubic foot. Instead of expanding, the mixture may be formulated such that shrinkage is limited or made to be generally negligible, unlike shrinkage which may occur Protective coating 18 may also be added to pole 10, for the purpose of enhancing ultraviolet protection and corrosion resistance and to produce a smooth surface. The coating 18 is applied during the manufacture of the pipe and is at least 0.001 inch thick. Protective coating 18 is clear, can be made with or without pigments, and includes specific ultraviolet absorbers and/or shields. An example of such a coating could be "Amerishield" as manufactured by Ameron Corp. or "Tufcote" as manufactured by DuPont. The composite pole of the present invention can furnish bending strength equal to or greater than Schedule 40 steel pipe (ASTM F-1083) of the same diameter, and its inherent corrosion resistance is far superior to that of steel. Moreover, the present invention actually furnishes a pole which will flex more than twice as far as steel and return to its original shape without failure. FIG. 2 shows another embodiment of a composite pole structure 100 of the invention. As shown, the inner surface 110 of the pipe 140 is roughened to form a regular or irregular pattern therein. In the illustrated embodiment, the inner surface 100 includes an irregular pattern defining a plurality of recesses 112 which increases the surface area contact between the core 120 and the pipe 140 when the core 120 hardens within in the pipe 140. Thus, a portion of the core 120 is disposed in the recesses 112 defining a mechanical lock between the core 120 and the pipe 140. The core 120, pipe 140, veil 160 and coating 180 are otherwise identical to the embodiment of FIG. 1. Alternatively, as shown in FIGS. 4a and 4b, instead of the recesses, ridges 112' or 112 can be molded or otherwise formed into the inner surface 110 of the pipe 140'. The ridges may be concave 112' (FIG. 4a) or convex 112' FIG. 4b) and may be in a regular or an irregular pattern. It can be appreciated, however, that the core 120 need not be of the type which expands its volume when it hardens to provide a force fit with the pipe 140, since the mechanical lock provides the desired locking of the core 120 to the pipe 140. Thus, a conventional type cement material may be employed as the core material in this embodiment of the invention. It can also be appreciated that the core material may be of the type discussed above, in which shrinkage is limited during hardening thereof FIG. 3 shows yet another embodiment of a composite pole structure 200 of the invention. As shown, an adhesive 250 is coated on the inner surface 212 of the tube 240 such that when the core 220 hardens it is chemically locked with respect to the pipe via the adhesive 250. The adhesive 250 is preferably SIKADUR 32 ® manufacture by Sika. However, any type of adhesive suitable for securing the resin pipe 240 to the hardened core may be employed. The core 220, pipe 240, veil 260 and coating 180 are identical to the embodiment of FIG. 1. It can be appreciated, however, that the core 220 need not be of the type which expands its volume when it hardens to provide a force fit with the pipe 240, since the chemical lock provides the desired locking of the core 220 to the pipe 240. Thus, a conventional type of cement material may be used as the core material in this embodiment of the invention. It can also be appreciated that the core may be of the type discussed above, in which shrinkage is limited during hardening thereof Tests were performed to determine the push-out strength or frictional resistance of the core material to the inner wall of the composite pole structure. The total load in pounds required to dislodge the core from the hollow tube was measured and divided over the unit area and represented in units of psi. The average frictional resistance of the core made in accordance with the embodiment of FIG. 1, (no mechanical or chemical locking of the core) was measured to be on average 25 psi over the entire inner wall surface of the pipe. With the addition of an adhesive 250 bonding the core 220 to the pipe 240 (FIG. 3) the average frictional resistance of the core was determined to be approximately 90 psi. Thus, there is a corresponding minimum increase in bending strength of approximately 30% as a result of a better bond between the core and the pipe which provides for a better transfer of shear between the structural component parts. With both expansion of the core 220 and the use of the adhesive 250 (FIG. 3), failure of the composite structure is often in the cohesive strength of the core 220 itself. Namely, the cohesive strength of the bond between the core and pipe can be stronger than the cohesive strength of the core 220. Additives 20 may be included in the core of the invention to improve the composite pole structure. For example, silica fume, an extremely fine aggregate that fills tiny voids in the core may be added to the core to improve the compressive thus, making he composite pole structure even stronger. Steel, glass or polymer fibers additives mixed into the core could also be employed. The fibers deter cracking which cause premature failures, provide higher stiffness, provide higher compressive strength and provide higher bending strength, all of which enhance the performance of the composite pole structure. FIGS. 5a and 5b show other embodiments of the invention, each having a roughened portion on at least a portion of an outside surface of at least one of the ends of the filled structure. It can be appreciated that the poles or filled structures of FIGS. 5a and 5b may be configured as disclosed in any of the embodiments of FIGS. 1-4b, but also include a roughened portion on an outside surface thereof, as explained below. As shown in FIG. 5a, the fiber reinforced pipe 140 of pole 300 has an outer surface 310. In the illustrated embodiment, the outside surface 310 includes an abrasive adhesive 320 coated on at least one end of the pole 300. The abrasive adhesive 320 includes an abrasive such as a grit material, e.g., sand, in an epoxy, and defines a roughened portion on the outside surface 310. When the pole 300 is driven into the ground, the roughened portion creates skin friction with the ground which increases the bearing load capabilities of the pole 300 as compared to that of a smooth pole. Thus, the pole 300 may be relatively shorter than traditional material pole (smooth steel and/or concrete poles) since it does not have to be driven as deep as the traditional poles to achieve the same load bearing. The abrasive adhesive defining the roughened surface works well in mounting the pole 300 in sandy ground, particularly when the size of the grits of the abrasive closely match the size of the grits of sand in the ground. FIG. 5b shows a pole 400 having a plurality of fiber rovings 412 wrapped about a lower portion of the fiber reinforced pipe 140 so as to extend from outside surface 410 thereof. Each of the fiber rovings 412 may be a singular fiber roving strand or may comprise a group of smaller roving strands. Thus, during manufacture of the fiber reinforced pipe 140, the fiber rovings 412 may be wrapped to extend from the outside surface 410 and cured to be integral with the pipe 140. In the illustrated embodiment, the fiber rovings 412 are disposed in spaced relation thereby defining a roughened portion on the outside surface 310. The fiber rovings 412 may be evenly or unevenly spaced. Further, the fiber rovings 412 are arranged so as to be generally perpendicular to the longitudinal axis 420 of the pole 400 so as to create more driving friction than would be created if the rovings 412 were more vertically oriented with respect to the longitudinal axis 420. The fiber rovings 412 create increased skin friction when driven into the ground, resulting in the advantages noted above, with reference to the embodiment of FIG. 5a. The fiber rovings 412 have been found to provide a pole having good load bearing capabilities in muddy soil or clay. In the illustrated embodiments, only a portion of poles 300 and 400 near an end thereof is roughened since one end portion is typically driven into the ground when the pole is used as a piling. In piling applications under water, the portion of the pole exposed to water is preferably smooth to prevent biological attack from mollusks, barnacles and the like, which have a more difficult time attaching to a smooth surface. Although two examples of surface roughening have been described above, it can be appreciated that the pole of the invention may be roughened any amount to produce increased skin friction with the ground. It is to be understood that the form of this invention as shown is merely a preferred embodiment. Various changes may be made in the function and arrangement of parts; equivalent means may be substituted for those illustrated and described; and certain features may be used independently from others without departing from the spirit and scope of the invention as defined in the following claims. For instance, structures may be produced without either veil 14 or protective coating 16 when the application does not require ultraviolet protection. Moreover, the diameter and cross sectional configuration of the external member may, of course vary, and the particular formula of the core could be changed as long as the requirements of the claims are retained. Further, although a generally round cross-sectioned pipe is disclosed, the composite structure may be in any shape or closed section, such as, for example a square, rectangular, oval etc, cross-section.	A filled structure characterized by the combination of high compressive and tensile strength to allow a high bending load includes a fiber reinforced resinous hollow structure having a tensile strength of at least 30,000 psi. The hollow structure has first and second ends, an inside surface forming a boundary which encloses a space, and an outside surface. At least a portion of the outside surface of one of the ends has a roughened portion sufficient to provide frictional resistance with the ground when the one end is driven into the ground. A hard core is disposed within the space enclosed by the hollow structure. The hard core has a density of at least 35 pounds per cubic foot and a compressive strength of at least 1500 psi. The hard core is formed from a mixture of particulate cementitious material and liquid.
You are an expert at summarizing long articles. Proceed to summarize the following text: This invention relates to a detection label for an anti-shoplifting system, comprising a housing accommodating an electrical circuit which by means of an electromagnetic interrogation field can be detected, a needle by means of which the detection label can be secured to an article to be safeguarded, and locking means for locking the needle. Such detection labels, sometimes referred to as wafers or responders or transponders, are known in practice in various embodiments. One example of a known wafer is described in British patent specification 1 570 508 (Nedap). In the prior wafers, the housing is provided with a lock in which the shank of the needle or spike can be locked. The head of the needle or spike is secured in the free end of a flexible arm, the other end of which is secured to the housing. The needle or spike is to be inserted into the lock through an aperture in the article to be safeguarded, or in the case of textiles, through the fabric of the article. The lock can in most cases be unlocked magnetically. The electrical circuit of the prior wafers for anti-shoplifting systems comprises a tuned circuit which comes into the resonant state in an interrogation field. The signal generated by the tuned resonant circuit can be detected with a receiver. Often, however, the energy absorbed by the circuit of the wafer is detected at the end of the transmitter which generates the interrogation field. The wafer according to the invention is suitable for both types of systems. In practice, inserting the needle and fixing it turns out to be a cumbersome operation, because the positioning of the needle in the opening provided in the wafer for the purpose requires some degree of accuracy, for which coordinated manipulation by both hands is needed. Another drawback of the prior wafers is that an alarm signal is only generated when the wafer is introduced into the interrogation field of the transmitter/receiver. Fraudulent attempts at removing the wafer from clothing without the appropriate uncoupling equipment, however, cannot be detected. British patent application 2 180 680 describes an anti-shoplifting system which comprises a plurality of safety clips each having a needle which can be stuck through a piece of clothing to be safeguarded and can be locked. These known safety clips, however, are connected through a fixed central device by means of a cord and do not comprise an electrical circuit which can be detected through an electromagnetic interrogation field by wireless means. Also, the known safety clips are not provided with needle guiding means. European patent application 0 266 294 describes a U-shaped safety clip for shop articles, comprising a needle which can be stuck through a piece of clothing and fixed in that position by means of a lock operable by a key. That safety clip is not provided with means for wireless detection either, but, like the clip described in the above British patent application 2 180 680, can only be used in one particular place, because the clip is provided with a cable inserted through a fixed eye in the shop. BRIEF SUMMARY OF THE INVENTION It is an object of the present invention to provide a wafer which does not have the drawbacks outlined above, and to which various security functions can be added in modular form. For that purpose a wafer is provided which has a fixed clip and an integrated needle, whereby the attachment of the wafer to an article is considerably simplified. The movement of the needle it guided through the construction, so that the wafer can be simply attached with one single hand movement. In the attached condition, the article to be protected, for example, a piece of clothing, is secured between the fixed clip and the wafer housing by means of the needle. In order that a alarm signal may be generated when the wafer is subjected to fraudulent manipulations a source of power is needed. If this power source is a battery, it must be possible for it to be removed and replaced when it is exhausted. However, the removal of the power source by unauthorized persons must be impossible, because in this way the wafer might become deactivated, at least as far as the fraud alarm is concerned. Because, in accordance with the present invention, the needle is designed to be within the housing of the label, this creates a simple possibility for one or more batteries to be mounted in a hollow push button which also serves to operate the needle. By adding to the basic structure of the wafer according to the invention a power source and a suitable electronic circuit, it is possible to generate an active alarm signal when the wafer is being tampered with. Signalling that the wafer is being tampered with can be considerably simplified when, in the locked position, the needle is biased into contact with the clip by spring means. In that case when the needle is cut or the clip broken, the needle is pushed further outwardly, which can be utilized to close an electrical contact. In this way an alarm signal can be obtained which in the non-active condition is currentless and so does not consume energy, so that an optimum service life of the batteries is ensured. It is also possible for a wafer according to the invention to be equipped, for example, with a piezoelectric buzzer or bleeper, which sounds a prolonged signal, which has a preventive effect. As it is not possible for a wafer to be secured to all types of goods to be safeguarded in the above-described manner, it is possible, according to the present invention, to use an accessory in the form of a cord or cable or the like. The cord or the cable etc. is inserted through an opening of the article to be safeguarded, and the ends of the cord are connected together and locked by means of the wafer according to the invention. In the wafer in the basic embodiment, the cord or the cable etc. may consist of steel wire which is difficult to cut through, with an eye at each end, through which the needle of the wafer can be inserted. In the embodiment in which a "tamper alarm" can be generated, this alarm function can also be operated, in accordance with this invention, through a specially constructed cord. BRIEF DESCRIPTION OF THE DRAWINGS Some embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings wherein: FIG. 1 is a diagrammatic vertical cross-sectional view taken on the line I--I of FIG. 2, and showing one embodiment of a detection label according to this invention; FIG. 2 is a cross-sectional view taken on the line II--II of FIG. 1; FIG. 3 is a cross-sectional view showing an example of an accessory with a cord for use with a detection label according to the invention; FIG. 4 is a side-elevational view, of a different embodiment of the detection label according to the invention in the inoperative position; FIG. 5 is a view similar to FIG. 4 which shows the detection label of FIG. 4 in the operative position; FIG. 6 is a vertical cross-sectional view, showing a further embodiment of the detection label of FIGS. 1 and 2; FIG. 7 is a cross-sectional view taken on the line VII--VII of FIG. 6; FIG. 8 is a cross-sectional view taken on the line VIII--VIII of FIGS. 6 and 7; FIG. 9 is a view similar to FIG. 6 showing the detection label in the operative condition; and FIG. 10 shows the detection label in cooperation with an accessory provided with a cord. DETAILED DESCRIPTION FIG. 1 shows diagrammatically a cross-sectional view of a wafer or detection label according to the present invention, in which a needle or spike 1 of the wafer is fully within and between a wafer housing 2 and a clip 3, in both the open and the closed position. In the open position, the needle is entirely within the wafer housing 2. Fabric of a piece of clothing can be slipped between the clip 3 and the housing 2. At the bottom of the housing, as viewed in the drawing, there is provided a push button 4 which in the open position projects from the housing. Needle 1 is at the top of push button 4, and is surrounded by a helical spring 5. The shank of the needle or spike points to a cavity 7 in clip 3. In the open position of the wafer, the needle or spike is within a guide bore 20 in the wafer housing, through which it extends in the open position of the wafer. In the embodiment shown, the guide bore is provided in a device 6 which can move towards and away from clip 3, and has a fabric clamping function. The wafer is thus prevented from being suspended exclusively by the needle, which could damage the fabric. In the closed position of the wafer, spring 5 exerts a force on fabric clamping device 6. When push button 4 is pushed into housing 2, the tip of needle 1 is stuck through an article to be safeguarded, such as a piece of clothing, into the cavity 7 of clip 3. In the closed condition, push button 4 is fully sunk within wafer housing 2. Spring 5 is compressed through this operation, so that the fabric of the piece of clothing or other article is clamped between clip 3 and fabric clamp 6. FIG. 2 is a cross-section perpendicular to the section of FIG. 1, and shows the wafer in the closed position. At the end of push button 4 facing the clip, one or more projections 8 are provided. When push button 4 is depressed, catches 9 catch behind projections 8. In this situation, push button 4 cannot fall back into the open position, and the wafer is locked. In the example shown, catches 9 take the form of leaf spring catches. The wafer is removed by means of an uncoupling apparatus specially constructed for the purpose. Through one or more magnets, the leaf spring catches 9 are drawn into a position in which projections 8 are released, so that push button 4 and hence the needle can be moved to the outside or open position and the wafer removed from the object being safeguarded. The uncoupling apparatus may, for example, comprise an annular magnet, shown diagrammatically at 27 in FIG. 2, which is capable of attracting the curved sections 9a of catches 9, to cause the catches to pivot outwardly relatively to intermediate pieces 28 connected to them, and also connected to print 21, to release push button 4. In this example the intermediate pieces 28 also serve as contact strips. The above-described basic construction of the wafer can be extended with an active alarm function. In that case, as shown in the cross-section of FIGS. 1 and 2, additional components are added. In push button 4, one or more batteries 12 are provided, together with two resilient contact lips 10 and 11 (FIG. 2). The leaf spring catches 9 in FIG. 2 are mounted either directly or through intermediate pieces 28, on a print 21, i.e., a wafer carrying an electronic printed circuit capable of generating an active alarm in the form of a bleep and/or a radio-frequency alarm signal, which is transmitted to a coil not shown and can be received, for example, by receivers mounted in the ceiling. Advantageously, the coil may be the coil of the conventional wafer circuit, which is present anyway. As shown in FIG. 2, the push button 4 is constructed so that, in the closed position of the wafer, battery 12 is pushed downwardly through needle 1 against the spring action of contact lip 11, so that the electrical connection between lip 10 and the battery is broken. In this situation no voltage is passed through the contact lips and the leaf spring catches to the print. When the needle 1 can move further outwardly, for example, because it is cut, or the clip 3 is broken, then, under the influence of the spring pressure of lip 11, the battery will be pushed against contact lip 10, as a result of which supply voltage is passed to the electronic circuit on the print, and an alarm is generated. The electronic circuit may, for example, be an oscillator circuit. The wafer may also comprise a buzzer or the like to be energized by the batteries. FIG. 3 shows a cord, to which the alarm function can be transmitted, if it has been added to the wafer. For this purpose, the contact lip 10, as shown in FIG. 2, is arranged to make electrical contact with spring 5. Furthermore, at the top of fabric clamping device 6, a metal strip 13 is provided, which is also in electrical contact with spring 5. The cord shown by way of example in FIG. 3 comprises a flexible tubular guide element, e.g. a closely-wound coiled metal spring 14, possibly provided with a plastic sheath, with a metal wire or cable 15 as a core. Metal wire 15 is fixed at one end of the cord to the metal spring 14, for example, through a weld or by being attached to an end member 26. The other end of the cord is provided with a hollow disk-shaped accessory 22 of insulating material, with the wire or cable 15 extending into the cavity 23 of accessory 22 through a radial bore 24. The end of wire or cable 15 in cavity 23 is provided with a cone or bead 19, and a helical compression spring 16, which tends to pull the bead, and hence wire 15, from the tube 14. Accessory 22 comprises a contact lip 17 and a slot 18 forming a kind of fork in which a corresponding end piece 25 at the free end of the cord can be placed. If now the cord is inserted through an opening of the object to be safeguarded, and closed through slot 18, the wafer or label can be provided around the plastic part of the cord by shifting the clip of the label around it and inserting the needle of the label through the accessory, which is provided with a bore 26 for the purpose, and locking it. In this situation, lip 17 makes contact with metal strip 13 in the fabric clamping device. When the cord is now cut or broken, the bead 19 will be pushed into contact with needle 1 of the wafer under the influence of spring 16. In this way, voltage is passed through the print, whereby an alarm is generated, because the head 1a of the needle is in contact with one pole of the battery or batteries. It is noted that, instead of the resilient contact lip 11, or in combination therewith, a compressive spring may be used between battery or batteries 12 and the end wall of push button 4. Also, it is not necessary for wire 15 to be made of metal or for tube 14 to be made of metal. FIGS. 4 and 5 show diagrammatically, and in side-elevational view, an embodiment of a detection label according to the invention with a frustoconical housing 30. At the truncated top of the housing, a push button 31 is provided, which is shown in FIG. 4 in the inoperative position, in which it projects from the housing. The push button serves to operate the needle, not visible in FIGS. 4 and 5, in the manner described hereinbefore, in order to move it to the free end of the fixed clip 32 located opposite the base of the conical housing. In the situation shown in FIG. 5, the push button has been depressed and the needle extends into the cavity in the clip. The needle is not visible, however, because the fabric clamping device 33 has also been moved towards the clip in the manner described hereinbefore. Push button 31 and housing 30 are designed so that the housing can be gripped by one hand and the push button operated with the same hand to push the needle through an opening in an article to be safeguarded or through the fabric of an article to be safeguarded. In the depressed position, the push button is preferably inaccessible from the outside, as shown in FIG. 5. Attempts at detaching or de-activating the detection label in an unauthorized manner are thus made more difficult. Batteries placed in the push button can only be removed in the inoperative position, i.e., the non-depressed condition of the push button. Clip 32 is connected to the rest of the housing through a connecting piece 34. In the embodiment shown, the connecting piece is provided with slots 35, which augment the audibility of an alarm buzzer or the like, if provided in the label. FIGS. 6 to 10 show various sections of an additional embodiment of a detection label according to the invention. Corresponding parts are designated by the same reference numerals as used in FIGS. 1 and 2. As in FIGS. 1 and 2, push button 4 is hollow, so that one or more batteries can be placed in it. For this purpose, for example, the push button may be provided with a cap which is detachable when the push button is in the inoperative position (FIG. 6). The batteries are pushed towards the head of needle 1 by a first contact spring 40 (FIG. 8). At the end of the needle head, there is further provided a second contact spring 41 (FIG. 8). In this example, the contact springs are continuously in contact with both the battery or batteries and the circuit on print 21, in contrast to the embodiment illustrated in FIGS. 1 and 2. The detection label of FIGS. 6-10 is accordingly arranged to detect the breaking of a connection and to generate an alarm signal in response thereto. FIGS. 6-8 show at 42 the coil of the passive circuit of the wafer. This coil may advantageously form part of the active alarm circuit of the wafer serving to generate an alarm signal when the wafer is being tampered with. Furthermore, a buzzer is shown at 43, which can be energized by the active alarm circuit. Other means capable of providing an acoustic alarm signal, such as a piezoelectric bleeper, for example, are also applicable. FIG. 6 shows the detection label in the inoperative condition. In that condition needle 1 is fully within fabric clamping device 6 surrounding the push button. Fabric clamp 6 has a slot 56 through which a lip 44 of a locking pawl 45 extends into the space within the fabric clamp. Pawl 45 is biased by a compression spring 46, and is capable to pivot against the action of spring 46, as shown by broken lines in FIG. 9. FIGS. 9 and 10 show the wafer in the operative condition. Push button 4 has been depressed, and lip 44 of pawl 45 is behind the shoulder 8 of the push button and thus prevents the push button from moving outwards again. Pawl 45 can be unlocked magnetically in known manner when the wafer is placed in an unlocking device provided for the purpose. FIG. 9 shows the detection label in the condition in which thick material is clamped between clip 3 and fabric clamping device 6. The broken lines indicate the position of the fabric clamp if no material, or very thin material has been placed between the fabric clamp and the clip. As shown in FIG. 9, a contact spring 47 is provided in clip 3 which in the operative condition of the wafer makes contact with needle 1 and, through the needle, with one pawl of the battery (batteries) 12. Contact spring 47 is accommodated in cavity 7 of the clip, but in this example, for reasons to be described hereinafter, also extends below an aperture 48 in clip 3 opening towards the fabric clamp. Through a wire 49 (FIG. 7), contact spring 41 is further connected to the electrical circuit of the wafer. If it is tried to pry loose the detection label, or to cut the needle or the like, the circuit of the battery through the needle, the contact spring and wire 49 to the electrical circuit is at least temporarily broken. The electrical circuit is arranged to generate an alarm signal in that case, for example, by energizing an acoustic device 43 and/or transmitting a radio-frequency signal. In this embodiment, too, an accessory with a cord can be used to safeguard articles which cannot be secured with a needle. Such an accessory is shown at 50 in FIG. 10. The accessory shown again has an opening for receiving the tip of needle 1. Located behind the opening is a contact lip 51 connected to conductor 52 of an electrical cord 53, which is at one end fixedly connected to the accessory. The contact lip 51 is clear of the contact spring. The other end of the electrical cord is provided with a second contact lip 54, which is also connected to conductor 52, and can be hooked into a cavity 48 of the accessory. The second contact lip 54 is shaped so that, if the accessory is placed in the wafer, lip 54 makes contact with contact spring 47 through the opening 48 in the clip. In this way, a closed circuit is again formed through the needle, the first contact lip 51, the cord, the second contact lip 54, the contact spring 47 in the clip and wire 49, which circuit is interrupted when the cord is severed or pulled loose. Such an interruption leads again to an alarm signal being generated. A detection label or wafer according to the invention can advantageously be designed so that the use of the passive form, i.e., that without a battery or batteries, and the active form in one and the same anti-shoplifting system is possible. Passive wafers, which may be of the known type, but also of the type according to the present invention with a fixed clip, are then for example used for normal articles, and the active wafers for more expensive articles. It is noted that, after reading the above, various modifications will readily occur to those skilled in the art. Thus, for example, it is possible to have both the passive and the active wafers generate a coded signal when activated by an interrogation field and/or by fraudulent operations. The code may be related, for example, to the nature of the article being safeguarded. One example of an electrical circuit suitable for this purpose is described in Netherlands patent 176 404. These and similar modifications are considered to fall within the scope of the present invention.	A detection label for an anti-shoplifting system, comprises a housing (2) accommodating an electrical circuit (21) detectable by an electromagnetic interrogation field, a needle (1) for securing the detection label to an article to be safeguarded, and a locking device (4, 8, 9) for locking the needle. The housing includes a fixed clip (3) which together with the rest of the housing encloses a slot-like free space, a cavity (7) for receiving the tip of the needle (1) which is placed within the housing, an operating push button device (4, 6) for moving the needle towards the clip, and a guide bore (20) in a fabric clamp (6) for guiding the needle during its movement toward the clip.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION [0001] The invention relates to tools for forming bores in the earth, especially rock, and particularly to rotary drill bits for use in oil and gas exploration and mining. [0002] Drag bits for drilling through rock are typically outfitted with hard, durable cutters. To improve wear, the cutters often possess contact surfaces made from diamond, typically in the form of polycrystalline diamond compact (PDC). PDC is an extremely hard and wear resistant material. [0003] Although PDC cutters are known to have one of the lowest rates of wear when operated at cooler temperatures, thermal damage to the diamond layer of the cutter begins at temperatures of approximately 700 degrees Celsius. Thermal damage lowers wear resistance and the PDC cutters become more susceptible to abrasive wear and breakage from impact. [0004] Greater tangential cutter velocity causes more friction, thus generating more heat. Cutters moving at higher tangential velocities will thus tend to operate at higher temperatures. At some velocity, frictional heat reaches a level sufficient to cause cutter wear rates to accelerate, reducing the life of the cutters. In conventional PDC drag bits, the tangential velocity of a cutter, when measured relative to the material being cut, depends on the distance of the cutter from the center of rotation of the drill bit. For a given angular velocity, the tangential velocity of cutter increases with the distance of the cutter from the bit's axis of rotation. Thus, a PDC cutter's intolerance of high temperatures limits, in practice, the diameter of the bit. [0005] Increased application of force also generates more heat. Cutters require more force to penetrate harder rock. Cutters dragging through harder rock have higher wear rates due to the increased application of force. Therefore, the critical point at which the wear rate begins to accelerate is also a function of hardness of rock in addition to the rotational velocity of the drill bit to which the cutter is attached. In softer rocks, accelerated wear rates do not occur until higher rotational speeds are used; in harder rocks, acceleration of the wear rate occurs at much lower rotational speeds. [0006] A number of additional factors also shorten the life of PDC cutters. [0007] First, a cutter's abrupt contact with rock formations also increases the rate of wear of PDC cutters. Drilling with conventional PDC drag bits require application of weight and torque to a drill string to turn the drilling tool face and drive the face into the formation. Torque rotates the bit, dragging its PDC cutters through the formation being cut by the cutters. Dragging generates chips, which are removed by drilling fluids, thereby forming a bore or drilled hole. The drilling action causes a reverse, corresponding torque in the drill string. Because of the length of the drill string, the torque winds the drill string like a torsion spring. If a bit releases from consistent contact with the formation being drilled, the drill string will unwind and rotate backward. Changing the tension in the drill string causes the drill bit to come into irregular, abrupt contact either with the sides of the bore or the exposed formation surface being cut. These irregular contacts can cause impact damage to the cutters. [0008] Second, drill strings will also vibrate, sometimes severely. Under typical drilling conditions, a drill string rotates at 90 to 150 rpm. These vibrations can also damage a drill bit, including the cutters, as well as the drill pipe, MWD equipment, and other components in the drilling system. [0009] Third, “bit whirl” further contributes to impact loads on PDC cutters. This complex motion of the drill bit is thought to occur due to a combination of causes, including lateral forces on the drill bit due to vibration of the drill string vibration, heterogeneous rock formations, bit design, and other factors in combination with the radial cutting ability of PDC bits. Whirl of a drill bit in a bore subjects PDC cutters on the bit to large impact loads as the bit bounces against rock or other material in the bore. Cutters on these drill bits will lose large chips of PDC from impact, rather than from gradual abrasion of the cutter, thereby shortening the effective life of the cutters and the drill bit. [0010] Drilling tools disclosed in U.S. Pat. No. 6,488,103 of Dennis et al., and in U.S. application Ser. No. 10/988,722, filed Nov. 15, 2004, both of which are incorporated herein by reference, address these problems by reducing the thermal and impact stresses on the cutters. The tools employ a plurality of satellite mills surrounding a central pilot bit. The satellite mills reduce the tangential velocity of the cutters along the periphery of the bore hole. SUMMARY OF THE INVENTION [0011] The invention pertains to an earth boring tool, or aspects thereof, having PDC cutters that overcomes one or more of these problems by combining on the same rotational axis a central bit and a relatively larger diameter reamer that extends beyond the central bit. In effect, the central bit bores the center of the hole and the reamer enlarges it. By turning the reamer at a relatively low angular velocity relative to the earth, the tangential velocity of the cutters on the reamer are kept low enough to reduce wear and other adverse affects associated with higher tangential velocities of the cutters. The central bit is allowed to rotate relatively faster, thereby permitting larger diameter holes to be bored without adversely affecting cutter performance or drilling rate. Cutting speed can be optimized, allowing the maximum efficiency without excess wear of the cutters. [0012] Several additional benefits are possible with such a tool. It will tend to create less vibration and chatter. Less force on the drilling tool is required for cutting. This in turn lowers the torque on the drill string, lessening the chance of the drill string of wrapping up. Lighter force applied to the tool also permits use of a lighter tubing having thinner walls to be used. [0013] Details of an example of such an earth boring tool are described below. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is a highly simplified, schematic representation of the drive system for turning a pilot bit and reamer for the drilling tool shown in FIGS. 2 and 3 . [0015] FIG. 2 is a side, elevation view of a first example of a drilling tool, sectioned its entire length along its axis. [0016] FIG. 3 is a side, elevation view of a second example of a drilling tool, sectioned its entire length along its axis. DETAILED DESCRIPTION [0017] In the following description, like numbers throughout the figures refer to like elements. [0018] Briefly, in the following example of an earth boring tool, the pilot bit and reamer are each driven by a separate motor, thereby avoiding the complexities of gears and problems occasioned by them. Examples of such problems include structural complexities necessary to have seals, with the attendant potential for failure. If seals are not used, there is a substantial risk of gear failure or jamming that is not easily addressed by merely hardening the gears. [0019] FIG. 1 schematically illustrates the functional and spatial relationships between two motors 10 and 12 , a drill string 14 , reamer 16 and a central bit 18 within an earth boring tool 20 . The reamer and central bit each possess a plurality of cutters 21 along exterior cutting surfaces. The central bit drills a pilot hole; the sleeve-shaped or donut-shaped reamer, since it has an wider diameter, widens the hole. These cutters are wear-resistant, and may be made from carbide, polycrystalline diamond or other super hard materials. Motor 10 , the casing (not shown) of tool 20 and drill string 14 to which the tool is attached are in a fixed relationship and do not rotate with respect to each other. Motor 10 has a rotating output 22 , with which motor 12 is in a fixed relationship. Thus, motor 10 effectively turns motor 12 . Reamer 16 has a fixed relationship with the rotating output 22 as well as motor 12 . Whether the reamer is connected with motor 12 or output 22 , it is in effect turned by motor 10 . Rotating output 24 of motor 12 turns central bit 18 . Depending on the direction of rotation of the outputs of the motors, their rotations can be additive, meaning that angular velocity of the bit 18 , relative to the tool and the earth through which the tool is boring, is the sum of the angular velocity of the rotating output of each motor. Thus the central bit will naturally turn at a relatively higher rate of rotation than the reamer. The relative angular velocity of the pilot bit to the reamer will depend on the rate of rotation of the output 24 of motor 12 . [0020] Counter-rotating the reamer and drill bit will reduce torque on the string and stress on the cutting tool. With this configuration, the angular velocity of motor 12 must overcome the opposite rotation of the output 22 of motor 10 . Preferably, the central, high-speed bit rotates right, to tighten threaded connections, and the low-speed reamer turns left. [0021] Using conventional positive displacement motors (PDMs)—also called “mud motors”—for motors 10 and 12 permits the motors to be powered by drilling fluid pumped down a drilling string. With their axes aligned with each other and the tool, drilling fluid will flow from one into the next, and then out the end of the tool in a manner to cool the cutters and clear cutting debris. A central stator of the first mud motor, motor 10 in the preceding schematic, remains stationary with respect to the casing of the tool and the drill string. An outer, sleeve-shaped rotor functions as output 22 . This outer rotator is then coupled with an outer, sleeve-shaped stator of the second mud motor, which corresponds with motor 12 . The construction of the second motor is the inverse of the first mud motor: the stator, or stationary part, is disposed on the outside of the mud motor, with the rotor formed on an internal, rotating shaft. This inverse construction or arrangement allows the two motors to be coupled for drilling fluid to flow straight from one into the other. It also permits the reamer to be easily coupled to the rotor of the first motor or the stator of the second motor. [0022] FIGS. 2 and 3 illustrate details of two examples of such an earth boring tool. These examples share certain characteristics and elements, which will be discussed first. Unless otherwise noted or apparent from the context, each element is symmetrical about the tool's central axis 28 . Each has a top connection subassembly 30 having a threaded rod box 32 for connection to a drill string. Connected to the top connection subassembly by support pin 34 , is a flex joint 36 . The flex joint has fixed relationship with (i.e., does not substantially rotate with respect to) the drilling string and tool, and extends down into a main body of each of the tools. The main body is defined in part by an outer tool casing 39 . [0023] Mounted within the main body of each of the tools include an upper positive displacement motor (PDM) 40 and a lower PDM 42 . One purpose of PDM 40 is to provide a relatively low-speed rotational output for turning a reamer. One purpose of PDM 42 is to provide a relatively high-speed rotational output for turning a pilot bit. However, PDM 42 is rotated by PDM 40 and, therefore, the true angular velocity of the “high speed” PDM 42 may not necessarily be higher than the angular velocity of the output of the upper, “low speed” PDM 40 . [0024] The upper, low speed PDM is coupled to a lower end of the flex joint 36 in a substantially non-rotating or fixed relationship by attaching stator 44 to flex joint 36 . Rotor 46 of upper PDM 40 , which is an elastomer, rotates an outer body 48 of the upper PDM 40 . Fluid under pressure flows from the drilling string (not shown) into passage 50 , which in turn carries it to the upper PDM 40 , causing the rotor 48 and, thus also, body 52 of the upper PDM to turn. Small arrows throughout the figures indicate the direction of fluid flow during operation. [0025] Body 54 of the lower PDM 42 connects to body 52 of the upper PDM. This connection is, in the example, threaded, though other types of connections may be used. The connection causes the body of the lower PDM to rotate with the body of the upper PDM. Stator 56 of the lower PDM 42 is thus coupled to, and turns with, the rotor 48 of the upper PDM 40 . Rotor 58 of the lower PDM is connected to a flex shaft 59 , which in turn is connected to lower shaft 60 . The flex shaft provides, in essence, a flexible coupling between the output of the lower PDM and the lower shaft that accommodates the eccentric movement of the rotor 58 with respect to the center line of the tool. A drill bit 62 , on which a plurality of cutters (not shown) are mounted, is attached to the free end of shaft 60 . The shaft includes a passageway 64 through its center. A portion of the drilling fluid exiting the lower PDM is diverted through the passageway to the drill bit. [0026] Reamer 66 couples to body 54 of the lower PDM 42 through inner bearing housing 68 . In the illustrated embodiments, reamer 66 is attached to inner bearing housing 68 by a threaded connection, and the bearing housing 68 is connected to the body 54 of the lower PDM by a threaded connection. [0027] Several sets of radial bearings support rotating components within the body of the tool, namely radial bearing assemblies 70 and 78 support the relative rotation of the upper and lower PDMs in each of the tools, and radial bearing assemblies 71 and 73 support rotation of the lower shaft. Radial bearing assembly 70 includes a radial bearing 72 and a bearing wear surface layer 76 disposed between the tool casing 39 and upper bearing housing 74 . The upper bearing housing is connected to body 52 of the upper PDM, and thus rotates with the body of the upper PDM. Bearing assembly 78 includes a radial bearing 80 disposed between lower bearing housing 68 and outer bearing housing 82 . The outer bearing housing is connected to casing 39 of the tool, preferably by a threaded connection. Bearing assemblies 71 and 73 are located at opposite ends of the lower shaft 60 . They include radial bearings 75 and 79 , respectively, each with a wear surface 79 . [0028] A set of thrust bearings limit movement of rotating components along the axis of the tool. Upper thrust bearing assembly 84 include a pair a fixed bearings 86 and 88 , and a pair of moving bearings 90 and 92 , each having a wear surface 113 . Spacer 94 acting against radial bearing 72 prevents upward movement of the fixed bearing 86 , and thus also of thrust bearing assembly 84 . Locking nut 96 stops upward movement of the radial bearing. Ledge 98 , which is integrally formed in casing 39 , prevents downward movement of fixed bearing 88 and thus also of the thrust bearing assembly. Moving bearings 90 and 92 are trapped by the fixed bearings. Ledge 100 transfers the load on the rotating components to the thrust bearing assembly. Some amount of lateral movement of elements of the thrust bearing assembly is desirable, as it permits drilling fluid to migrate into and down through outer passageway 102 , through the upper radial bearing assembly and then through the upper thrust bearing assembly. Spacer 103 prevents downward movement of bearing wear surface layer 76 . [0029] Lower thrust bearing assembly 105 has a construction similar to that of the upper thrust bearing, with fixed bearings 106 and 108 and moving bearings 110 and 112 , each with a wear surface 113 . The thrust bearing is trapped by the set of radial bearings 71 and 73 , with shoulder or ledge 114 stopping upward lateral movement of the bearings. Spacers are used to space apart the bearings and facillitate flow of drilling fluids through the bearings. Spacer 116 keeps fixed bearings 106 and 108 spaced apart at the correct distance. Lock nut 118 screws onto a threaded interior surface of inner bearing housing 68 to prevent downward movement of the radial bearing assemblies 71 and 73 and thrust bearing assembly 105 . Like the other radial and thrust bearings, this thrust bearing assembly is also lubricated and cooled by drilling fluid. However, it is cooled by fluid exiting lower PDM 42 . [0030] It is preferred that at least the thrust bearings, due to expected high loading, be made of a wear resistant material, such as a polycrystalline diamond compact or similar material. [0031] The bearing assemblies are, in the example tools described above and shown in FIGS. 2 and 3 , not sealed. Drilling fluid pumped through the tool lubricates and cools the bearings. As indicated by arrows, a portion of the drilling fluid flowing into the tool is diverted into for lubricating the radial bearing assemblies 70 and 87 and thrust bearing assembly 84 . The fluid travels through passageway 102 to bearing assembly 78 before it exits through opening 104 between the bottom end of outer bearing housing 82 and a shoulder of the inner bearing housing 68 . Similarly, a portion of drilling fluid exiting lower PDM 42 flows, as indicted by the arrows, through radial bearing assemblies 71 and 73 , and thrust bearing assembly 105 , before exiting the bottom of the tool. [0032] Referring now just to FIG. 2 , central, high speed bit 62 , which turns at a high speed relative to the tool, extends beyond the end of tool, in front of the reamer. It forms a pilot hole having a relatively smaller diameter, and the reamer enlarges it. In the embodiment of FIG. 3 , reamer 66 leads the central bit, the reamer first cutting an annular bore and then the central bit subsequently crushing the core.	An earth boring tool includes two coaxially-aligned, positive displacement motors. One motor turns a pilot bit and the other turns a reamer concentric with the pilot bit. The central bit bores the center of the hole and the reamer enlarges it. The central bit is rotated relatively faster, while rotation of the larger diameter reamer is relatively slow. The tool can thus be used to bore larger diameter holes without slowing drilling rates or adversely affecting performance of the cutter elements due to higher tangential velocities.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND [0001] Tools in the downhole drilling and completions industry are often located in a borehole by the use of no-go profiles (or landing nipples, radially inner restrictions, etc.). While these no-go profiles are relied upon for providing positive indication that a tool is properly set, too much load on the tool can deform or swage the tool and/or the no-go profile. If a tool becomes swaged into a no-go profile, retrieval of the tool can become difficult and the tool and profile can become damaged. As a result, advances to the setting and subsequent retrieval of tools, particularly those overcoming the above problems, are well received by the industry. BRIEF DESCRIPTION [0002] A system for setting and retrieving a tool including a tubular having a first profile and a tool having a second profile, the first and second profiles complementarily formed and engagable together for enabling the tool to be located in a borehole with respect to the tubular, the first profile or the second profile at least partially formed from a degradable material, the degradable material degradable upon exposure to a downhole fluid. [0003] A system for setting and retrieving a tool including an engagement including a first profile of a first component and a second profile of a second component, the engagement operatively arranged for locating the first component in a borehole with respect to the second component, the first profile at least partially degradable by exposure to a downhole fluid. [0004] A component of a no-go engagement including a first profile operatively arranged to engage with a second profile of the no-go engagement for locating a tool downhole, the first profile at least partially degradable upon exposure to a downhole fluid. [0005] A method of setting and retrieving a tool downhole including landing a first profile of a tool at a second profile of a tubular, exposing the first profile or the second profile to a downhole fluid for degrading the first profile or the second profile at least partially. BRIEF DESCRIPTION OF THE DRAWINGS [0006] The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: [0007] FIG. 1 is a quarter-sectional view of a system having a no-go engagement between a tubular and a tool; [0008] FIG. 2 is an enlarged view of the area generally encircled in FIG. 1 ; [0009] FIG. 3 is a quarter-sectional view of the system of FIG. 1 having dogs of the tool set into recesses of the tubular; [0010] FIG. 4A is a cross-sectional view of the system taken generally along line 4 A- 4 A in FIG. 1 ; [0011] FIG. 4B is a cross-sectional view of the system taken generally along line 4 B- 4 B in FIG. 1 ; [0012] FIG. 5 is a quarter-sectional view of the system of FIG. 1 after application of an additional load on the tool; [0013] FIG. 6 is an enlarged view of area generally encircled in FIG. 5 ; and [0014] FIG. 7 is a quarter-sectional view of the system of FIG. 1 after a ring of the no-go engagement has been removed by degradation. DETAILED DESCRIPTION [0015] A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. [0016] Referring now to FIG. 1 , a system 10 is shown having a tool 12 being run in a tubular 14 . As shown in more detail in FIG. 2 , the system 10 includes a no-go engagement 16 comprising a landing profile 18 on the tubular 14 and a no-go ring 20 on the tool 12 having a corresponding profile 22 . Once received at the landing profile 18 , positive interference or radial overlap with the profile 22 of the ring 20 prevents the tool 12 from traveling further downhole. The tool 12 is illustrated throughout the Figures in the form of a lock mandrel, but it will be appreciated that other tools or downhole components (the term “tool” used collectively herein) could utilize the no-go engagement of the current invention. That is, for example, tools benefiting from the current invention include those that carry a load in excess of the setting load such as plugs, tubing hangers, check valves, etc. [0017] Accordingly, after landing at the profile 18 , a setting load is applied to the tool 12 , specifically on a sub 24 for the tool 12 . The sub 24 includes a mandrel 26 for engaging with one or more dogs 28 and expanding the dogs 28 radially outwardly into complementarily formed recesses 30 in the tubular 14 , as shown in FIG. 3 . This creates positive interference or a radial overlap between the dogs 28 and the tubular 14 , which can be appreciated by comparing FIGS. 4A and 4B . [0018] Under high pressure or an additional force or load after being set (e.g., the tool including or being formed as a plug housing, check valve retainer, tubing hanger, etc., as noted above), the tool 12 is shifted downhole such that the dogs 28 result in an engagement at a surface 32 of the recesses 30 , as shown in FIG. 4 . Once the dogs 28 are fully engaged against the walls of the recesses 30 , the tubular 14 , via the dogs 28 , picks up the weight of the tool 12 and any components hanging therefrom or pressures applied thereto. [0019] Shifting the dogs 28 downhole to engage at the surface 32 , however, causes the ring 20 of the tool 12 to also shift downhole, becoming swaged into the landing profile 18 of the tubular 14 . As shown in more detail in FIG. 5 , the ring 20 is deformed a distance D into the landing profile 18 of the tubular 12 . This swaging makes retrieval of the tool 12 difficult as it significantly increases the force required to pull the ring 20 , and therefore the tool 12 , free of the tubular 14 . [0020] In order to facilitate the retrieval of the tool 12 in the system 10 , the no-go engagement 16 is at least partially degradable. “Degradable” is intended to mean that the ring is disintegratable, dissolvable, corrodible, consumable, or otherwise removable. It is to be understood that use herein of the term “degrade”, or any of its forms, incorporates the stated meaning. The ring 20 is formed as any known degradable material, such as a metal, polymer, composite, etc. that is removed or weakened by exposure to a downhole fluid, for example, water, oil, acid, brine, etc. In FIG. 6 the ring 20 has been removed by exposure to one of the downhole fluids, for example, by spotting acid to the ring 20 . In another example, the material of the ring 20 could be selected such that is degrades more slowly over time, and is sufficiently weakened or removed by the time any additional load is applied to the tool 12 . Once the ring 20 is removed, there is no longer a swaged engagement of the tool 12 with the tubular 14 , thereby facilitating removal of the tool 12 . It is also to be appreciated that degrading of the ring 20 could occur before application of the additional pressure or force on the tool 12 , such that swaging never occurs, in which case the dogs 28 would engage with the surface 32 before the application of any additional pressures, loads, or forces (e.g., for or with operation of a plug, check valve, tubing hanger, etc.). [0021] Although the system 10 is shown with the tool 12 disposed radially inwardly of the tubular 14 , in another embodiment a tool could be located radially outwardly of a tubular, with a degradable ring disposed radially inwardly of the tool. In another embodiment, the degradable ring could be formed as part of the tubular with the tool including a non-degradable landing profile. The ring 20 could be a c-ring, a full ring held by a retainer, a full ring that is press fit onto or into the tool or tubular, etc. Furthermore, although the term “ring” is used consistently herein, it is to be appreciated that other members or portions of a non-go engagement could be used for decreasing the amount of undesirable swaging between two components in order to facilitate retrieval of one or both of the components. [0022] While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.	A system for setting and retrieving a tool including a tubular having a first profile and a tool haing a second profile, the first and second profiles complementarily formed and engagable together for enabling the tool to be located in a borehole with respect to the tubular, the first profile or the second profile at least partially formed from a degradable material, the degradable material degradable upon exposure to a downhole fluid.
You are an expert at summarizing long articles. Proceed to summarize the following text: This application is a continuation, of application Ser. No. 673,377, filed 11-20-84 now aband. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a building block system. 2. Description of the Prior Art Various shapes of building blocks have been proposed over many years for use in building vertical and horizontal walls. A relatively common proposal is of substantially T-shaped blocks, i.e. a block consisting solely of a stem limb and a cross limb, the stem limb extending substantially perpendicularly from the middle of the cross limb, examples being disclosed in British Patent Specification No. 590,291, French Patent Specifications Nos. 1067762 and 2299468 and U.S. Pat. No. Re. 14,904. In all of these cases, the block is laid such that the cross limb extends in the general plane of the wall, whilst the stem limb extends perpendicularly to that plane. Swedish Patent Specification No. 150829 discloses a building block which, although it appears to be substantially T-shaped when seen in front elevation and rear elevation. The block actually consists of six limbs, of which four provide the front and rear T-shapes and of which each of the other two, links one end of the cross-limb of the front T-shape with the nearer end of the cross-limb of the rear T-shape. This building block has this special shape because it is used to form ventilation or like channels in the wall. Although substantially T-shaped blocks, when interfitted with the free end of each stem limb face-to-face with the cross limbs of two adjacent blocks, utilize the interfitting to support each other at two opposite sides of the six sides of the block, they provide no similar support at any of the other four sides. U.S. Pat. Ser. No. 829,480 discloses a paving and building block system wherein each block consists of two block-form parts whereof a larger part protrudes from the smaller part on four sides. These blocks can interfit such that the larger parts of four outer blocks overlap the larger part of an inner block at its respective four sides. Although forces applied to the major external face of the larger part of the inner block are borne by the larger parts of the four outer blocks, forces applied to the major external face of the smaller part of the inner block are not borne by any adjacent blocks. In the above-mentioned U.S. Pat. No. Re. 14,904, each block has the end faces of its cross limb diverging towards its stem limb, and has the lateral faces of its stem limb substantially parallel to the respective nearer end faces of its cross limb and thus diverging away from the cross limb. Moreover, those two intermediate faces of the cross limb between these respective end faces, on the one hand, and these respective lateral faces, on the other hand, converge towards the longitudinal axis of the cross limb progressing inwardly. There is thus formed a keying arrangement of substantially Z-form which, in a wall constructed from the blocks, resists forces on those faces of any one of the blocks at the major faces of the wall. However, only one shape of block with such keying arrangement is provided, so that the system is of very limited use. Although the Specification discloses use of the blocks in a vertical wall, the blocks are arranged with their cross limbs vertical and their stem limbs horizontal. Thus, a bottom layer of special blocks has to be provided if the wall is to be laid on a planar foundation. Federal German Patent Specification No. 1926239 discloses paving slabs each of which has at each of two opposite edge sides thereof a profile including a substantially Z-form key, the profiles on most of the slabs being identical to each other. The substantially Z-form keys of each slab are arranged to extend parallel to each other in the plane of the horizontal wall formed by the slabs. However, they are offset relative to each other along the respective opposite edge sides of the slab and are thus unsuitable for use in building a vertical wall with the substantially Z-form keys extending horizontally. French Patent Specification No. 1352121 discloses a building system employing three shapes of interfittable elements, these shapes being substantially Z, substantially T and substantially L-shaped. However, forces against the free end face of the stem limb of such T-shaped element or against the free end face of the longer limb of such L-shaped element are not borne by the adjacent elements except by way of conventional fastening means, for example riveting, used to fix the elements together. SUMMARY OF THE INVENTION This invention seeks to provide a building system in which blocks are employed that are of compound shape, that is to say, are not basically rectangular parallelepipeds. The block employed in a system in accordance with the invention may be substantially T-shaped, substantially Z-shaped or may be dove-tailed and may co-operate with other compound-shaped blocks to produce buildings or other structures in which the various blocks strengthen and support one another with, or without, interlocking cooperation. It is possible for the buildings or other structures to be completed, in some cases, without mortar or other binding material between the blocks or, in other cases, to employ a relatively small amount of mortar or other binding material between the blocks as compared with buildings and other structures produced from conventional blocks, particularly bricks. The present system advantageously employs blocks which are pre-fabricated to a high degree of precision and with which the required fitting together, especially interlocking, of the blocks will not be achieved, during the erection of a building or other structure, unless the individual blocks are correctly disposed relative to one another and register accurately. Thus, if a mistake is made in positioning a block relative to others that have already been laid, the error is almost immediately very obvious and can quickly and easily be corrected. No cutting or breaking of any block is necessary since the system advantageously includes the use of complementary blocks such as end blocks, corner blocks, or junction blocks. In the case of a building or other structure having upright walls, a minimum of checking is necessary upon the erection of those walls once the dimensions of the base of the building has been calculated and said base has been accurately marked out. An important feature of the system is the fact that the same block can by employed in the construction of floors and roofs as are used to erect vertical walls thus producing a fully integrated building system in which, once an initial choice of the various possible block shapes has been made, the number of different shapes of pre-fabricated block that are actually employed in a single building or other structure can be quite small. According to one aspect of the present invention, there is provided a wall comprising a plurality of unitary building blocks each consisting of only two limbs which are a stem limb and a cross limb, the stem limb extending substantially perpendicularly from the middle of the cross limb, and the longitudinal axis of the cross limb extending in the general plane of the wall, wherein the improvement comprises the longitudinal axis of the stem limb also lying in said general plane. Use of T-blocks in this manner in a wall, which may be a vertical wall, or a horizontal wall, for example a floor or a roof, gives a greater degree of flexibility in building construction, in particular with walls intended to bear no load or low loads, since these walls can be of lesser thickness than when the stem limbs of the blocks are perpendicular to the general plane. According to another aspect of the present invention, there is provided a unitary building block comprising only two block-form parts whereof one part protrudes from the other part at first and second adjacent sides of said block to provide first and second keys thereat, wherein the improvement comprises said other part protruding from said one part at third and fourth adjacent sides of said block to provide third and fourth keys thereat. This building block has the advantage that, when interfitted with identical building blocks in a wall, the blocks support each other not only against forces applied to two opposite sides of the block but also against forces applied to another two sides of the block. According to a third aspect of the present invention, there is provided a range of building elements of various shapes, wherein the improvement is comprised in that the elements of various shapes are provided with substantially Z-form keys which are of substantially identical linear and angular dimensions to each other and each of which has its intermediate limb at an acute angle to its other two limbs. This provision of substantially Z-keys on a range of variously shaped elements gives a greater degree of flexibility and strength in building construction. According to a fourth aspect of the present invention, there is provided a substantially vertical wall comprising a plurality of unitary building blocks each formed at first and second opposite sides thereof with substantially Z-form keys. The keys of said blocks are substantially identical to each other and interfitting, and each block having at third and fourth opposite sides thereof alternating with said first and second opposite sides thereof respective substantially parallel faces. The improvement comprises said faces and the substantially Z-forms of the keys of the blocks extending in substantially horizontal planes. A vertical wall constructed in this manner with blocks provided with Z-keys has the advantage that a lowermost course of the blocks can be laid directly on a horizontal foundation surface without requiring interposition of differently shaped blocks. According to a fifth aspect of the present invention, there is provided a building block including at first and second opposite sides thereof respective first and second substantially Z-form keys whereof the substantially Z-forms extend in a substantially parallel manner to each other. The improvement comprises the first and second keys being situated directly opposite each other along said sides. This block has the advantage that a plurality of them can be laid with their keys interfitting without requiring inversion of alternate blocks and without alternate blocks protruding significantly. According to a sixth aspect of the present invention, there is provided a wall comprising a plurality of unitary building blocks each consisting of only two limbs which are a stem limb and a cross limb. The stem limb extends substantially perpendicularly from the middle of the cross limb, and the longitudinal axis of the cross limb extends in the general plane of the wall. The improvement comprises the longitudinal axes of the stem limbs of some of the blocks extending in said general plane and the longitudinal axes of the stem limbs of others of the blocks extending perpendicularly to said stem limbs of some of the blocks. This arrangement of substantially T-shaped blocks is particularly useful in providing a relatively strong wall. BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be clearly understood and readily carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: FIG. 1 shows a perspective view from above of a corner of two vertical walls of identical substantially T-shaped blocks of a building block system, FIG. 2 shows a view similar to FIG. 1 of a modified arrangement of the substantially T-shaped blocks in the walls, FIGS. 3A and 3B are a fragmentary elevation and a fragmentary plan view of a course of blocks in a wall of FIG. 1 or 2, FIGS. 4A and 4B are a perspective view and a vertical sectional perspective view of one of the blocks of that course, FIGS. 5A and 5B are views similar to FIGS. 3A and 3B of the course with a modified version of the block, FIGS. 6A, 6B and 6C are a perspective view, a plan view and another perspective view of a second modified version of the substantially T-shaped block, FIGS. 7A and 7B are a plan view and a perspective view of a corner substantially T-shaped block usable with the block of FIG. 6A, FIGS. 8A and 8B are a perspective view and a plan view of two of those corner blocks interfitted, FIG. 9 shows a perspective view from above of three walls built of the block of FIGS. 1 and 2, FIGS. 10A and 10B shows a plan view and a perspective view of a modified version of the block of FIGS. 1 and 2 for use in the walls of FIG. 9, FIG. 11 shows a view similar to FIG. 10B of a modified version of the block therein, FIG. 12 shows a view similar to FIG. 10B of another modified version of the block therein, FIG. 13 is a view similar to FIG. 10B of a further modified version of the block therein, FIG. 14 is a view similar to FIG. 9 showing the walls built of a further modified version of the substantially T-shaped block, FIG. 15 is a view similar to FIG. 9 showing the walls built of a variation of the block therein, FIGS. 16A, 16B and 16C are a perspective view, a plan view and a side elevation of a substantially Z-shaped block of the system, FIGS. 17A, 17B and 17C are end elevations of respective versions of a substantially Z-form key applicable to various of the blocks of the system, FIG. 18 shows a perspective view of part of two interkeying courses of the block of FIG. 16A, FIG. 19 shows an end elevation of the two courses of FIG. 18, but with a variation of the block of FIG. 16A, FIG. 20 shows a modified version of the block of FIG. 16A, FIG. 21 shows a fragmentary plan view of walls comprising the block of FIG. 16A, FIG. 22A shows a perspective view of part of a course of another modified version of the block of FIG. 16A, FIG. 22B shows a detail of FIG. 21, but modified, FIGS. 23A and 23B show a perspective view and a plan view of a substantially dovetailed-T-shaped block of the system, FIG. 24 shows a view similar to FIG. 21 of the walls comprising the block of FIG. 23A, FIG. 25 shows a fragmentary perspective view of a horizontal wall, in this case a floor, comprised of the blocks of FIGS. 6A and 23A, and FIG. 26 shows a fragmentary perspective view of a wall comprised of the block of FIGS. 1 and 2. DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference is made firstly to FIGS. 1 to 15 of the drawings which show the use of building blocks 1 that are substantially T-shaped. FIGS. 1 and 2 of the drawings show two upright walls 2 and 3 of a building or other structure formed from such T-shaped blocks. It will be seen that, in each horizontal course of blocks, neighboring blocks are alternately upright and inverted and that, in the structure of FIG. 1, each block is inverted relative to blocks which are vertically thereabove or therebeneath. In the structure shown in FIG. 2, each block in each course has the same disposition as does each block which is vertically thereabove or therebeneath. It will particularly be noted that, in both cases, the T-shaped blocks co-operate to form a 90° junction between the two upright walls without the need to employ blocks of any other shape. It will immediately be apparent that, measured in the general plane of its wall, the horizontal or cross limb 4 of each block is three units long, the vertical or stem limb 5 thereof is one unit long, and each limb 4 and 5 is one unit wide. In fact, the basic T-shaped block of FIGS. 1 and 2 is preferably given tapered projections 6 to 8 and depressions 9 to 11 as shown in FIGS. 3 and 4 for a hollow block 12 and each one unit square in effective area, or projections 6' to 11' and depressions 6" to 11" each with an effective area of one unit by one-half unit, as shown in FIGS. 5. These projections and depressions provide significant keys between the blocks 12, enabling them to be fitted satisfactorily together without the use of mortar or other binding material when a wholly or principally dry construction is required. Moreover, the projections and depressions co-operate with each other to form satisfactory seals at the joints between the blocks which is a considerable advantage if the hollow blocks are to be filled with an initially foamed or liquid insulation material or with foamed or other concrete. FIGS. 6, 7 and 8 of the drawings illustrate the form and use of blocks which may conveniently be described as Z-key, T-blocks. In FIGS. 6, the end faces of the cross limb 14 of the substantially T-shaped block 15 and the lateral faces of the stem limb 16 thereof are of a shape to give substantially Z-form keys 17. The keys 17 are identical to each other, especially in their linear and angular cross-sectional dimensions, with the intermediate limb 18 of each key being at an acute angle to its other two limbs 19. FIGS. 7 shows a corner substantially T-shaped block 20 which differs from the block 15 chiefly in that the key 17' of one branch of the cross limb 14 is arranged at a rear face of that cross limb. FIGS. 8 show two blocks 20 interfitted correspondingly to the blocks A and B in FIG. 1. The substantially T-shaped blocks of FIGS. 6 to 8 are, in any construction employing them, keyed to their neighbors on two sides and this produces equilibrium among the forces acting on each block. It is noted that Z-keyed blocks are usable in slab form as floors and also in slab form as roofs which latter can be employed either with, or without, additional supports. There are four basic versions of the embodiment of the system which principally uses substantially T-shaped building blocks. These four versions have been found to be the most satisfactory as regards ease of construction, handling, simplicity, ease of production of the blocks, versatility in use of the blocks and the need to produce a minimum number of accessory blocks for use at, for example, wall ends and wall junctions. The first of these four versions is illustrated in FIGS. 1 and 2, the second in FIGS. 9 to 13, the third in FIG. 26 and the fourth in Figure 15. It will be apparent that the versions shown in FIGS. 9 to 15 inclusive employ the substantially T-shaped blocks lying perpendicularly to the wall (i.e. with their cross limbs in the general plane of the wall and their stem limbs perpendicular to that plane. Referring to FIG. 9, the vertical walls 30, 31 and 32 extending perpendicularly to each other consist of substantially T-shaped identical blocks 33 with cross limbs 34. The cross limbs 34 are three units long and one unit wide and stem limbs 35 one unit square. The substantially L-shaped identical blocks 36 have stem limbs 37 two units long and one unit wide and cross limbs 38 one unit square, and identical square-section blocks 39 one unit square. FIGS. 10 shows one of the blocks 33 with the end faces of its cross limb 34 and the lateral faces of its stem limb 35 consisting of substantially Z-form identical keys 17 which differ from the keys 17 of FIGS. 6 only in that their faces are perpendicular to the plane of the block. FIG. 11 shows a block 33 differing from that of FIGS. 10 only in that it has substantially Z-form keys 40 whereof the limbs of the substantially Z-shape are at right angles to each other. The block 33 of FIG. 12 is usable in walls according to both FIGS. 1 and 9 and has its keys 41 of substantially V-shape with the limbs of the substantially V-shape lying in a plane perpendicular to the axis of the stem limb 35. The block 33 of FIG. 13 differs from that of FIG. 12 only in that its keys 42 are of a cylindrical concave or cylindrical convex form. FIG. 14 shows the walls 30 to 32 constructed of substantially T-shaped blocks 50, substantially L-shaped blocks 51 and substantially square-section blocks 52. FIG. 14 differs from the blocks of FIG. 9 chiefly in that the substantially T-shaped blocks each have one or both of those two faces 53 thereof intermediate the end faces of its cross limb, on the one hand, and the lateral faces of its stem limb, on the other hand, converging towards that face 54 of the cross limb opposite the stem limb. In the version of FIG. 15, each substantially T-shaped block 50' is of elongate formation. Each of the four versions of the embodiment of the system which principally employs substantially T-shaped blocks may be solid, or wholly or partly hollow, and may have plain and/or patterned or other textured faces. It will be apparent that many different combinations of precise shape, size, materials, surface texturing and so on are possible that are too numerous to discuss individually. The particular type which is chosen will depend upon individual preference, climatic conditions, geographic situation and local traditions of building. It is noted that, whilst prefabricated concrete will generally be employed and most blocks will be hollow in construction, other materials can equally well be used, if preferred, such as pre-stressed concrete to form blocks usable for vertical walls, floors, roofs and so on, but a construction employing concrete is not essential and the blocks can be made from, for example, glass-reinforced plastics, natural wood and/or plywood. The use of the building system which has so far been described enables strong buildings or other structures to be made either in dry form or semi-dry form using considerably less mortar or other binding material than is employed in the formation of traditional brick/block buildings and the like. The described system has numerous advantages as compared with traditional building systems. These advantages include stability both during and after erection of a building or other structure, ease of erection, simplicity in aligning the blocks without long experience of such work being necessary, and the use of an absolute minimum of auxiliary tools, measuring instruments and other gadgets. The blocks can be such as to interkey, giving increased strength to the vertical wall, floor, roof or the like which is being produced simultaneously. The blocks will eliminate errors such as discrepancies in level and the formation of crooked, zig-zag, curved or other incorrectly disposed courses of blocks. The system is versatile since it can employ different forms of keying and can employ any chosen one, or any chosen suitable combination, of the different blocks that have already been described and those that will be described below. As well as being very suitable for the construction of dwelling houses and other buildings, the system can be used for many other purposes such as, for example, the paving of roads, pathways, pavements and the like and for the cladding of new or existing buildings. Although the blocks will usually be formed from conventional concrete, they can, as has already been mentioned above, be formed from other materials which include, in addition to the examples already mentioned, light-weight concrete, clay, gypsum and synthetic plastics whether or not reinforced with glass fibre or the like. Where appropriate, buildings or other structures can be produced without mortar or other binding material between the blocks but grouted cavities can be included, where required, for strength or insulation. If required, a building or other structure can be formed in such a way as to be capable of being readily dismantlable by including therein removable keying blocks or removable locking bolts. The blocks may be given surface textures designed to simulate the use of a traditional method of construction when viewing the exposed surfaces of a building or other structure formed from such blocks. It has been found that, using principally the substantially T-shaped blocks to form a building or other structure, those blocks, when accurately produced, fit together in the manner shown in FIGS. 1 and 2 of the drawings in such a way as automatically to prevent inaccuracies in horizontal or vertical disposition, provided only that the foundation or footing is itself correctly disposed. The interengagement of the blocks automatically prevents vertical and horizontal inaccuracies from occurring. The fact that the blocks fit tightly together produces a strength which is comparable with that achieved by using traditional bricks or blocks that are connected to one another by mortar or other binding material. Considerable time is, of course, saved by wholly or principally omitting mortar or other binding materials since the builders do not have to wait for the mortar or the like to set before the blocks can be relied upon for supporting purposes. Although the blocks are pre-fabricated, a building or other structure which is to be formed principally therefrom is actually constructed in a very similar manner to the use of traditional bricks and blocks except that, generally speaking, mortar is used very sparingly, if at all. The final building or other structure will not have the appearance of a monolithic concrete mass but rather the appearance of a somewhat differently patterned, but otherwise traditional, block or brick construction, thus avoiding an unusual external appearance which tends to discourage builders and the customers for their products. Builders that work substantially only in the traditional way will find no difficulty nor strangeness in using this system since the system comprises placing a large number of relatively small blocks in pre-determined positions relative to one another as is, of course, done when using traditional bricks and building blocks. As well as being employed in the construction of actual buildings, paths, roads and the like and the cladding of new or existing buildings, this system can be employed in producing either permanent or temporary shuttering, substantially T-shaped blocks which are formed from glass fibre reinforced plastics or wood being particularly suitable for shuttering purposes. If exceptional strength is required in the blocks, they may be formed from glass fibre reinforced concrete. However, the particular choice of material will naturally depend upon the nature of the building or other structure that is to be formed and the purpose for which it is required. The hollow interiors of the blocks can, for extra strength, be filled with concrete or cement grout and it is possible to insert reinforcing bars into those interiors, before pouring the concrete or grouting. It has already been mentioned that the hollow blocks can be filled with insulation material, such as urea-formaldehyde foam, by either pouring or injection. The system is particularly convenient for forming temporary buildings or other structures since the blocks and other necessary items can be supplied in a partially assembled condition with post units bolted to beam units merely requiring the interlocking blocks to be correctly positioned. Under such circumstances it is, of course, necessary that provision should be made for disassembling the temporary building or other structure in one of the ways briefly discussed above. It will be realized that the blocks that have been described can be provided in any required sizes although it is desirable that the size and weight should not exceed that which can readily be handled by a single workman. The blocks that have briefly been described with reference to FIG. 15 can, on the other hand, be of such a size that mechanical assistance is required to move them. It is possible to provide blocks other than those shown in FIG. 15 to form a range of modular units that are basically of T-shaped cross-section together with accessory units as may be required at wall ends, wall junctions, the margins of access openings and the like. The second and third versions of the substantially T-shaped blocks may, if required, be of brick-sized dimensions and may be made from baked clay and other materials from which conventional bricks are formed. In a building or other structure using such bricks, it is desirable to grout the junctions between them at regular intervals, as may be necessary having regard to the particular building or other structure that is being produced. In the case of hollow blocks of this form, the block may be filled with mortar to produce columns or pillars and to strengthen the construction at the junctions between walls. When erecting a building or other structure using the first version of the blocks that has been described with reference to FIGS. 1 and 2 of the drawings, it will be remembered that these blocks do not possess any interkeying features and it is therefore desirable, although not absolutely essential in all cases, to use mortar, grouting or other binding material in each pair or tier of blocks, using further mortar, grouting or other binding material between superposed pairs or tiers of blocks. The blocks that are required at the corners and ends of walls are basically similar to the substantially T-shaped blocks themselves, except the form of keying matches that employed in the substantially T-shaped blocks. In employing the third version shown in FIG. 26 to form a building or other structure, much the same technique is used as with the first version but the relative disposition of the blocks is different. The substantially T-shaped blocks 60 with cross limbs 61 and stem limbs 62 in the general plane of the wall interfitting with substantially T-shaped blocks 63 with cross limbs 64 and stem limbs 65 perpendicular to the limbs 61 and 62, respectively. The thicknesses of the substantially T-shaped blocks employed can be varied, and in particular reduced, to allow different external patterns to be produced together with different relative dispositions of the blocks. This third version can, if desired, be combined with the second version, using the two versions alternately in successive tiers of the blocks. A second basic embodiment of this building system employs blocks that are not T-shaped but that co-operate with one another by way of keys that are still substantially Z-shaped. Such blocks are particularly, but not exclusively, useful in forming prefabricated panels, partitions and the like. A minimum of mortar or other binding material is required at the junctions between the blocks. The substantially Z-shape of the key can be varied but it has been found convenient to employ four basic forms of the key any of which will join the blocks quickly and effectively together without essentially employing any mortar or other binding material. It is possible to build a wall or other structure employing substantially Z-keyed blocks in a semi-dry form, overlaying every tier of the blocks with mortar or other binding material to secure the superposed tiers together in a conventional way. If a fully dry construction is preferred, it is desirable to incorporate end keying systems of substantially V-form, substantially arcuate, or substantially Z-form into the blocks to ensure that a building or other structure can be erected quickly and accurately whilst automatically maintaining stability and both vertical and horizontal alignment. FIG. 16 shows a substantially Z-shaped block 70 consisting of two block-form parts 71 of which one part protrudes beyond the other on two of the six sides thereof and of which the other part protrudes beyond the one part on another two of the six sides. As a result of such protrusion, substantially four Z-shaped keys 72 to 75 are formed at the four sides, the substantially Z-shapes of the two opposite keys 72 and 74 being parallel and identical and of an acute-angled form, whilst the substantially Z-shapes of the two opposite keys 73 and 75 are of a right-angled form although parallel and identical to each other. As can be seen from the grids in FIGS. 16A and 16C, each block 70 is four units high, and each part 71 being two units high. The top and bottom faces of the block are each four units square; the intermediate limbs of the substantially Z-shape of the keys 72 and 74 are each two units long; the mid-point of the substantially Z-shape of each of the keys 72 and 74 is in a straight line with the free ends of that shape; and the intermediate limb of the substantially Z-shape of each of the keys 73 and 75 is one-third unit long. FIGS. 17A, 17B and 17C show three different forms of acute-angled, substantially Z-shaped key. The key of FIG. 17A is that of FIGS. 6, 7, 8, 10 and 16. Figure 17B shows a key whereof the intermediate limb 80 is one unit long and the other two limbs 81 each extend, as measured in a direction parallel to the limb 80, one unit. In FIG. 17C, the key is similar in proportions to the key of FIG. 17A, but extends over only two units of the four-unit height of the block. FIG. 18 shows two courses of the blocks 70, illustrating that not only do the blocks interkey in each course by means of the keys 72 and 74 but the blocks interkey between courses by means of the keys 73 and 75. FIG. 19 shows that the keys 73 and 75 may also be of an acute-angled, substantially Z-shape. FIG. 20 illustrates a substantially Z-shaped block 90 with acute-angled substantially Z-shaped, parallel, identical keys 91 and 92, the intermediate limb 93 of each substantially Z-shape extending obliquely inwards. FIG. 21 is a plan view showing vertical walls 100 to 102 of a building that are formed by employing hollow blocks exhibiting the key of FIG. 17A, but FIG. 21 also shows the shapes of blocks that are required at a right-angled junction between two walls, two forms of T-junction between walls, and a cruciform junction between four walls, FIG. 22A illustrates hollow, substantially Z-form keyed, substantially Z-shaped blocks 110 which are used as permanent formwork for the construction of beams together with details of one way of fitting those blocks 110 together. FIG. 22B shows the shape of auxiliary hollow blocks 120, 120' that may be used surroundingly to support upright reinforcing rods or the like that are interconnected by strengthening wires. The substantially Z-shaped blocks that have been described herein can be employed in much the same situations as the substantially T-shaped blocks discussed above and, to a large extent, have the same advantages, as compared with the blocks that are employed in conventional building systems, as do those above-discussed blocks. There now follows with reference to FIG. 23 a description of a third basic embodiment of blocks employable in a building system which blocks 130 are of dove-tailed substantially T-shape and will hereinafter be called, for the sake of brevity, "dove" blocks. Such blocks are again particularly, but by no means exclusively, useful in constructing pre-fabricated panels, partitions and the like, very little, if any, mortar or other binding material being required at the junctions between the blocks. The dove blocks again employ substantially Z-form keys for interengagement and, once again, these keys may be of various shapes but conveniently are provided in four different versions as has already been described above with reference to FIGS. 17 to 20. Again, as already briefly described with reference to FIGS. 16 to 22, the dove blocks can advantageously be used in buildings or other structures of semi-dry form, each tier of dove blocks being overlaid with mortar or other binding material to secure it to the superposed tier in a substantially conventional manner. Again, if a substantially fully dry construction is required, it is preferable for the dove blocks to incorporate end keys of one of the same forms, and for the same purposes, as have already been mentioned with reference to FIGS. 16 to 19. Each dove block is actually shaped to comprise two substantially Z-shaped keys 131 each extending over the whole of one side of the block. This form of block has the particular advantage that, in use, the forces acting on the opposite ends thereof will almost always substantially counterbalance one another so that a particularly structurally stable building will result. The dove blocks 130 have substantially the same versatility of usage, and advantages as compared with the bricks or blocks that are employed in conventional building systems, that have already been discussed above in regard to the version of the system which principally employs substantially T-shaped blocks. FIG. 24 is a plan view, somewhat similar to FIG. 21, showing a plurality of the hollow dove blocks 130 employed in vertical walls 100 to 102 which also include matchingly shaped cruciform connecting blocks 132, "half" wall end blocks 133, T-junction blocks 134 and right-angled corner blocks 135. A description will now be given of ways in which the various forms of block that have so far been described can be employed in forming buildings and other structures. When substantially T-shaped or other blocks of the kind that have been described, having substantially Z-form keys, are used in co-operation with one another, the keys will effectively lock adjoining blocks together by directing the forces which act upon the junctions between the blocks and otherwise upon the blocks themselves in such a way as to enhance or reinforce the stability of the structure that is composed of said blocks. In particular, the keys transform the tensile forces to which the described blocks are subject into compressive forces which latter forces will not normally crush building materials of the kind used to produce blocks, unless these forces are excessively strong. FIG. 25 illustrates one form of floor that may be constructed of substantially T-shaped blocks arranged with their stem limbs horizontal in a pre-cast concrete or steel beam or timber joist framework 140 that is of matching cross-sectional shape and that provides beams or joists at pre-determined substantially regular intervals. It will be noted that the substantially T-shaped blocks exhibit substantially Z-form keys of the kind shown in FIG. 20 and that similarly keyed dove blocks are also employed to fill the gaps which would be left if the substantially T-shaped blocks alone were used. It is important, when using the blocks in the way that is illustrated in FIG. 25 that the blocks should be forced tightly against one another in a horizontal direction that is perpendicular to the lengths of the beams or joists of the co-operating framework. Under such circumstances, the blocks will co-operate effectively with one another to form a stable floor in which no underneath support, between the beams or joists, is necessary. A tie beam may often advantageously be employed to maintain the blocks firmly pressed against one another as just described, such tie beam being either pre-cast or cast in situ. The use of a tie beam for this purpose is particularly advantageous when the blocks are in the form of roof slabs. Obviously, there is a limit to the span of blocks which will remain reliably interconnected, without support, merely by the co-operation of their own interkeying portions, this limit being dependent upon the sizes of the blocks that are employed, the strength of the material from which they are made and the load that, in use, they will be called upon to bear. It is again possible to employ pre-cast or pre-stressed beams in supporting co-operation with the blocks, the blocks of a floor or the like that is formed in this way needing no mortar, grouting or other binding material. If necessary, further strengthening can be produced by forming substantially Z-shaped keys on those surfaces of the floor blocks that are substantially perpendicular to the surfaces carrying the keys that have already been mentioned. It can sometimes be an advantage to secure pre-cast or pre-stressed beams together to form a block in the form of a frame. This has the advantage that the beams will be lighter in weight than is conventional, thus avoiding the need for heavy lifting machinery and other mechanical handling equipment to move various parts of the building or other structure that is being erected into their appointed positions. Once again, if the beams are provided with substantially Z-form keying as described above, the advantage that the blocks automatically position themselves relative to one another in both vertical and horizontal directions is immediately attained. Also, since no mortar or other binding material is really necessary between the automatically interlocking blocks, a roof can be placed on a building or other structure erected using this system without having to wait for mortar or other binding material to set and attain a required degree of strength.	A building system for the construction of walls, floors, roofs, paths and roads employs prefabricated blocks having compound shapes which are such that at least a majority thereof each exhibit projections or recesses arranged to co-operate interkeyingly with the projections or rcesses of other blocks of the system, whereby the blocks can be assembled without the essential use of mortar or other intervening binding material. The blocks may be substantially T- or Z-shaped, having a hollow formation and being flat-laid, or disposed upright, in horizontal courses in vertical walls. The hollow interiors of the blocks may be filled with strengthening material or heat-and sound-insulating material or reinforcing bars may extend through aligned hollow interiors in the superposed courses. Compound-shaped corner and junction blocks are employed, where required.
You are an expert at summarizing long articles. Proceed to summarize the following text: [0001] This application is a continuation-in-part of pending U.S. application Ser. No. 13/987,952, filed Sep. 17, 2013. BACKGROUND OF THE INVENTION [0002] This invention relates generally to apparatus enabling reliable in and out use of a door, with enhanced security and safety. [0003] There is continuing need for safety and security at doorways, and for compact door latching installations contributing to security. There is also need for apparatus having unusual advantage in construction, in operation, and providing improved results, as embodied in the present invention, as will be seen. SUMMARY OF THE INVENTION [0004] It is a major object of the invention to provide improvements in door opening and closing controls, enhancing in and out security at doorways; and to provide improvements in sealing of door edges with doorway frames, and at the meeting edges of pairs of doors. [0005] Basically, door locking and unlocking apparatus embodying the invention includes: [0006] a) a lock actuator assembly sized to fit within a door, and operatively connected to a latch at a door upper edge, with the option of adding a locking bolt at the door lower edge, [0007] b) a push bar carried by the door at the door inside and operatively connected to the lock actuator assembly to control unlatching of the latch, [0008] c) a handle carried by the door at the door outer side, and operatively connected to the lock actuator assembly, to control unlatching of the door only after positioning of a key to effect unblocking of the actuator assembly, with the option of having the lever or handle always active. [0009] A further object is provision of the actuator assembly to include a first part bodily movable in response to push bar displacement to transmit actuation to a vertically movable latch actuator. As will be seen, the actuator assembly typically includes a rotor operatively connected to the handle and to said first part. The rotor is rotatable to transmit actuation to the latch actuator(s), in response to displacement of said handle, there being means blocking rotor rotation until key turning to unblock the blocking means. [0010] An added object is to provide a clutch, internal to the actuator assembly operatively connected with the rotor to initially resist rotor rotation by the handle and subsequently to allow handle rotation after predetermined torque application as from the door handle at the outer side of the door, thereby allowing handle rotation, once the predetermined torque has been exceeded, not allowing the lock mechanism to open, and protecting the lock mechanism from damage. In this regard an assembly is provided wherein said assembly includes a lock bar movable between door locking and unlocking positions, and first and second push bars respectively to operate from door inside and outside handle positioning to control said lock bar movement. The lock bar typically has two pivoted sections respectively operable by said first and second push bars. Further, a slidable coupler is received in an opening formed by said lock bar sections, one opening in one section sized to block coupler movement relative to said one lock bar section whereby the door remains latched, and a second of said openings in the other lock bar section sized to allow coupler movement relative to said second lock bar section, whereby the door becomes unlatched. One lock bar section is movable in response to door handle movement at the outer side of the door and with associated movement of a first push bar, when the door is key unlocked, and the other lock bar section is movable in response to door handle movement at the inner side of the door, and with associated movement of a second push bar, when the door is or is not key locked. [0011] Yet another object is to provide a door having an interior space opening only toward a vertical edge of the door, the actuator assembly received in and concealed in that space, the door being free of latching at said door vertical i.e. side edge. [0012] Further objects concern provision of movable door edge structure, which is adjustable to seal off against the door frame in closed position of the door, as at vertically spaced locations along the door vertical edge. [0013] These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which: DRAWING DESCRIPTION [0014] FIG. 1 is a front elevation showing a lockable door system, and frame; [0015] FIGS. 1 a and 1 b show door latching control units, in a door; [0016] FIG. 2 is a section taken on lines 2 - 2 of FIG. 1 ; [0017] FIG. 3 is an enlarged elevation showing construction of a latching control unit, in closed door latching position; [0018] FIG. 4 is a view like FIG. 3 , showing the FIG. 3 unit in door unlatched position; [0019] FIG. 5 is a horizontal section taken through a closed door and showing sealing elements; [0020] FIG. 6 is an enlarged view taken on lines 6 - 6 of FIG. 5 ; and FIG. 6 a shows two opposed edges of two movable doors; [0021] FIG. 7 is an enlarged view taken on lines 7 - 7 of FIG. 5 ; [0022] FIGS. 8 and 9 are sections showing door structure, and in relation to hinging and frame structure; [0023] FIG. 10 is a view showing roller assisted latching at the upper edge of the door; [0024] FIG. 11 is a view like FIGS. 3 and 4 , but showing elements in greater details; [0025] FIG. 12 is a fragmentary elevation as in FIG. 11 , showing operation; [0026] FIG. 13 is a view like FIG. 12 , showing further operation; [0027] FIGS. 14 and 15 are views like FIG. 13 , showing yet further operation; [0028] FIGS. 16-18 are side elevations showing push bar operation, in relation to key locking and unlocking; [0029] FIG. 19 show a push bar operating link; [0030] FIG. 20 shows sections of a push bar; and [0031] FIG. 21 is a perspective view of slider, as also seen in FIGS. 14 and 15 . DETAILED DESCRIPTION [0032] In FIG. 1 , a door 10 is shown in closed position relative to a door frame 11 having upright edges at 11 a and 11 b , and upper and lower horizontal edges 11 c and 11 d . The door has corresponding edges at 10 a - - - 10 d. A locking control apparatus 13 is located inside the door adjacent door edge 10 a, and between door panels 10 e and 10 f. [0033] Latching structures 15 and 15 a are located at the top and optionally at the bottom of the door, there being no latching at the door vertical edge 10 a, for security. Latching control rods 16 and 17 extend vertically inside the door, from apparatus 13 to the latching structures, whereby latch 20 on rod 16 is movable into and out of latching relation with receptacle 20 a on the doorway upper frame, and latch 21 on rod 17 is simultaneously movable into and out of latching relation with receptacle 22 in the doorway lower frame. [0034] The latch rods are simultaneously movable toward the control unit 13 to unlatch the door, in response to manual pushing of a push bar 23 carried by the door at the inner side of the door; and also in response to turning of a handle 24 carried by the door at the outer side of the door, when handle rotation is unblocked by blocking mechanism within the control apparatus 13 , such handle blocking and unblocking being controlled by a key 26 inserted into the door at 26 a , and rotated, from the outer side of the door. Accordingly, intrusion through the doorway, from the exterior, is key controlled or configured to have an always active lever; whereas escape through the doorway, from the interior, is always available, as by pushing of the push bar. [0035] FIGS. 5 and 6 show adjustable door vertical edge 10 a, with sealing material 100 carried by the door in a recess 31 at the edge. A threaded adjuster 32 engages a carrier 33 having a flanges 33 a received between door panels 10 e and 10 f. The adjuster head 32 a controllably engages the movable door vertical edge to adjust its position, toward or away from the frame (or opposing door) edge 11 a, to adjust door sealing upon door closure. Typically, the seal wall is adjusted to contact the frame, in door closed position. Multiple adjustment locations spaced apart vertically, are indicated at 250 , in FIG. 1 , to seal the gap which may vary in width along door vertical edge. FIG. 6 a schematically shows similar FIG. 6 structure, employed at opposed edges 140 and 141 of two movable doors, in face to face relation. See also the same or similar structure at FIG. 7 , with seal 34 carried by the door proximate the frame edge 10 b. A stop 35 carried at the frame has a head 35 a engaging a wall 36 of the door edge to limit and control positioning of the seal 34 . Door pivot at 38 controls pivoting of door edge panel 39 relative to doorway frame panel 40 . [0036] In the above, latch rods 16 and 17 and latches are held in latching position by cam positioning in the actuator train, until release, and when latch rods are in latch release position, gravitational force exertion on the mechanism holds the rods retracted against movement into distended latching position. This obviates need for springs to hold rods in position, and simplifies overall structure and operation. [0037] Referring now to FIG. 3 it shows the door latching apparatus 13 in door locked or latched position, and to FIG. 4 showing 13 in door unlatched position. It includes a receptacle 14 fitting in door recess 14 a, and containing control elements operatively connected to the latch rods 16 and 17 . [0038] Actuator plate 45 , connected at 40 to latch actuator rod 16 , is displaced downwardly in response to rightward movement of link 46 caused by pushing of the push bar 23 , as can be seen in FIG. 4 . This occurs in response to clockwise pivoting movement of link 47 about axis 98 . In this regard, link 46 is coupled at 49 to rotor 50 rotate it clockwise, to displace 47 to FIG. 4 position, causing 45 to be displaced downwardly, and plate 45 a to be displaced upwardly. [0000] If external rotor 24 is rotated manually, it likewise causes rotor 50 to rotate clockwise; however, the handle cannot rotate if the actuator coupled to 50 , is blocked, as at location 52 in FIG. 4 , by lever 53 . Turning of the key 26 in slot 26 a serves to unblock rotation of 51 , by limited rightward rotation of lever 53 . [0039] If rotation of handle 24 is blocked and excess torque is applied, provision is made for disengagement of a coupler in the handle torque transmission path. This is shown, schematically, by coupler 66 , in FIG. 4 , coupled to handle 24 at 67 , and to rotor 50 . [0040] In FIG. 8 , a modified door 160 has front and rear vertical panels 161 and 162 , and door interior 163 . Channel shaped receptacles 164 and 165 , U-shaped in section, fit between the panels, and open oppositely endwise to receive sealing structure as shown in FIG. 6 . FIG. 9 also shows the receptacles as well as adjustable door edge sealing elements 32 and 32 a, and sealing walls 164 a and 165 a. The receptacles are box shaped as shown and move toward or away from frame edges as threaded adjusters 32 and 32 a are rotatably adjusted. A hinge 166 has plate connection at 167 to receptacle 164 and at 168 to door frame 169 . When the door is closed and receptacle 164 is closed into frame space 170 , the hinge is concealed from eye view 171 . [0041] In FIG. 10 , rollers or guides 150 are carried by latch plate 151 moved up and down by latch rod 16 , in guide slot 152 in plate 152 attached to the door. [0042] Spring 153 holds arm 154 in pivoted position, with protrusion 155 engaging frame 156 , blocking release of downward travel of rod 16 , until that rod is pulled downward. [0043] FIG. 11 is a view like FIGS. 3 and 4 , but showing elements in greater detail. See also FIGS. 16-21 . That assembly includes a lock bar 200 movable between door locking and unlocking positions, and first and second push bars 201 and 202 respectively to operate from door inside and outside handle positioning to control such lock bar movement. The lock bar 200 typically has two side-by-side sections 200 a and 200 b (see FIG. 20 ) pivoted at 250 , and respectively pivotally movable by the push bars 201 and 202 . See FIGS. 16-18 . [0044] One lock bar section 200 a is pivotally movable in response to outside door handle 203 movement at the outer side of the door, and with associated movement (to the right, in FIG. 18 ) of a first push bar 201 , as when the door is key unlocked and openable. If the door remains locked by the key 210 , push bar 202 remains in FIG. 16 position, and the party, at the outer side of the door is unable to open the door without a key. With a key, that person can effect rightward movement of the push bar 202 , to displace lock bar section 200 b to FIG. 17 position, enabling rotation of the rotor 50 , and unlatching of the door. [0045] The other lock bar section is movable to FIG. 17 rightward position in response to door handle movement at the inner side of the door, and with associated rightward movement of the second push bar 202 . See FIG. 17 . Lock bar section 200 b is thereby carried to the right by a slider 215 having a leg 216 engaging wall 217 of lock bar section 200 a. The lock bar sections shown in FIG. 17 do not then block rotation of rotor 50 , enabling door unlatching. Slider 215 is slidable in the opening 217 in bar section 200 a, as between positions shown in FIGS. 17 and 18 . Slider 215 is also referred to as a coupler, herein. Accordingly, the invention extends to provision of a slidable coupler received in an opening formed by said lock bar sections, one opening in one section sized to block coupler movement relative to said one lock bar section whereby the door remains latched, and a second of said openings in the other lock bar section sized to allow coupler movement relative to said second lock bar section whereby the door becomes unlatched. [0046] Push bar structure also appears in FIGS. 12-15 . Push bar operating links are shown at 220 and 221 .	In a lockable door system, the combination comprising a door locking first assembly installable in a door for control of operable use to lock or unlock the door, an upper assembly including a locking plunger, and to guide plunger travel upwardly at door top level into locking and unlocking position, an actuator assembly including a rotor rotatable by handle or push bar to control door locking and unlocking, and connecting the rotor with the plunger, and door edge sealing structure.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION [0001] The present invention generally relates to excavating apparatus and, in a preferred embodiment thereof, more particularly provides an excavating adapter/tooth point assembly in which the tooth point is retained on a nose portion of the adapter for limited rocking motion relative thereto while a curved rear end surface area of the tooth point slidingly bears against a complementarily curved front surface area of a base portion of the adapter. [0002] Large excavating buckets, dippers and the like are typically provided with a series of earth-cutting teeth which are each formed from two primary parts—a relatively large adapter, and a relatively small replaceable tooth point. The adapter has a base portion which is connectable to the forward lower lip of the bucket, and a tapered nose portion onto which the tooth point is removably secured, with the tapered adapter nose being received in an interior pocket portion of the point, by a suitable connecting pin or other connecting structure. Compared to that of the adapter, the useful life of the point is rather short—the adapter typically lasting through five or more point replacements until the tremendous earth forces and abrasion to which the adapter is subjected necessitates its replacement. [0003] As conventionally designed, adapter/tooth point assemblies of this type are configured in a manner such that the adapter nose has a tapered configuration and is snugly and complementarily received in a tapered interior pocket portion of the tooth point in a manner limiting vertical rocking movement of the point relative to the adapter during excavating operations. While this snug tapered interfit between the adapter nose and a replacement tooth point captively retained thereon has been a long-accepted design feature in conventional adapter/tooth point assemblies, it has at least one well known disadvantage arising from this purposely snug fit between the tooth point and the adapter nose. [0004] Specifically, after the assembly has been used in excavation tasks, the tremendous front-to-rear loads imposed on the tooth point tends to rearwardly drive it along the tapered adapter nose to an extent elastically deforming the tooth point side walls in lateral directions which, in turn, tends to firmly clamp the tooth point onto the adapter nose to an extent which often renders the subsequent task of removing the worn point from the adapter nose an inordinately difficult one. [0005] In view of this it can be seen that a need exists for an adapter/tooth point assembly in which this problem is eliminated or at least substantially reduced. It is to this need that the present invention is primarily directed. SUMMARY OF THE INVENTION [0006] In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, specially designed excavating apparatus is provided that comprises an adapter illustratively securable to a front edge portion of an excavating lip structure, a wear member representatively in the form of a replaceable tooth point, and a connection structure which is representatively in the form of a connector pin. [0007] The adapter has a base with a curved front surface, and a nose projecting forwardly from the curved front surface. The wear member has a curved rear surface through which a pocket area forwardly extends, the pocket area being configured to removably receive and laterally envelop the adapter nose, and the curvature of the rear wear member surface being complementary to that of the front surface of the adapter base. Preferably, the curved front surface of the adapter base has a forwardly convex curvature, the curved rear surface of the wear member has a forwardly concave curvature, and the curved front adapter base surface slidingly engages substantially all of the complementarily curved rear wear member surface. When the adapter nose is placed in the wear member pocket area, the connector structure is inserted through aligned openings in the adapter nose and wear member to releasably retain the wear member on the adapter. [0008] According to a key feature of the present invention, when the wear member is operatively mounted on the adapter, and the curved rear wear member surface is slidingly and complementarily engaged with the curved front surface of the adapter base, the wear member is permitted to pivot relative to the adapter through a limited arc (generally centered about an axis rearwardly offset from the connector structure) in a manner causing the curved wear member rear surface to slide along the curved adapter base front surface. In this manner, reactive loads created by rearwardly directed operating forces on the wear member are desirably shifted to the curved adapter base surface as opposed to being positioned more forwardly on the adapter nose. [0009] Representatively, the adapter nose has a stabilizing tip portion with a front end surface that engages an inner end surface of the wear member pocket area, and a lateral clearance area is defined within the pocket area around the adapter nose therein. This clearance area causes a portion of the stabilizing tip portion to act as an abutment surface that limits the pivotal movement of the wear member relative to the adapter. The clearance area also prevents the wear member from being tightly wedged on the adapter nose, thereby facilitating removal of the wear member from the adapter nose. [0010] According to another feature of the invention, the wear member has a pair of opposite outer side walls which extend rearwardly past the curved rear surface of the wear member and define abrasion shield structures that protectively overlie opposite side surface portions of the adapter base. [0011] Illustratively, the wear member has a pair of opposite first and second outer side walls through which an aligned pair of first and second connection openings extend into the pocket area, the adapter nose has a third connection opening extending therethrough in alignment with the first and second connection openings, and the connection structure extends through the first, second and third connection openings. Representatively, the connection structure extends along an axis parallel to and spaced forwardly apart from the axis about which the wear member is pivotable relative to the adapter, the first and second connection openings have non-circular shapes and have curvatures generally parallel to the curvature of curved front adapter base surface, and the third connection opening has a circular cross-section. BRIEF DESCRIPTION OF THE DRAWINGS [0012] [0012]FIG. 1 is a partially cut away, somewhat simplified perspective view of a specially designed excavating adapter/tooth point assembly incorporating therein principles of the present invention; and [0013] [0013]FIG. 2 is an enlarged scale, partially cut away, simplified cross-sectional view through the assembly taken generally along line 2 - 2 of FIG. 1 and illustrating the assembly connected to a representative excavating bucket lip. DETAILED DESCRIPTION [0014] As illustrated in FIGS. 1 and 2, the present invention provides a specially designed adapter/tooth point assembly 10 which may be suitably secured to a front edge section 12 a of a lip portion 12 of a bucket structure used in excavation operations. Assembly 10 is elongated in a left-to-right or front-to-rear direction and longitudinally extends along a horizontal axis A 1 . The assembly 10 includes an adapter member 14 , a wear member representatively in the form of a removable tooth point 16 , and a suitable elongated connector structure 18 which is representatively a connector pin having a circular cross-section along its length, but which may be of an alternate construction if desired. Connector pin 18 longitudinally extends along a horizontal axis A 2 Which is transverse to axis A 1 . [0015] The adapter 14 includes a generally U-shaped base portion 20 having a closed left or front end section 22 from which vertically spaced apart top and bottom side legs 24 , 26 rearwardly extend, legs 24 , 26 defining a cavity 28 therebetween. Front end section 22 has a forwardly facing, convexly curved outer end surface 30 from which a reduced cross-section tapered nose portion 32 forwardly projects, the rear end of the nose 32 being circumscribed by the convexly curved end surface 30 of the adapter base 20 . Outer or front end surface 30 curves rearwardly about a horizontal axis A 3 which is parallel to and spaced rearwardly apart from the axis A 2 . Adapter nose 32 has, at its front end, a stabilizing tip portion 34 with generally horizontal top and bottom sides 36 , 38 and a front end surface 40 . Diverging top and bottom side surfaces 42 , 44 of the adapter nose 32 respectively slope upwardly and downwardly from the tip portion 34 to the convexly curved outer end surface 30 . A circular connection opening 46 , positioned rightwardly or rearwardly from the tip portion 34 , extends horizontally through the adapter nose 32 between its opposite left and right sides as viewed from the front end of the adapter nose 32 . [0016] Tooth point 16 has a pointed leading or front edge portion 48 , opposite left and right vertical side walls 50 and 52 , and rearwardly and vertically diverging top and bottom side walls 54 and 56 disposed at the is rear of the tooth point 16 . The right or rear end surface 58 of the tooth point 16 has a forwardly concave curvature substantially identical to the forwardly convex curvature of the outer end surface 30 of the adapter base portion 20 . A forwardly and inwardly tapered pocket 60 extends forwardly into the tooth point 16 through its concavely curved rear end surface 58 and is laterally enveloped by the outer side wall section of the tooth point 16 . Pocket 60 has a shape generally complementary to that of the adapter nose 32 , and forwardly terminates within the tooth point 16 at a vertical front end surface 61 . Aligned connection openings 62 (only one of which is visible in the drawings) are formed through the opposite vertical side walls 50 , 52 and are spaced apart along the axis A 2 . Openings 62 have non-circular configurations, are slightly elongated in the vertical direction, and are curved generally parallel to the curvature of rear tooth point surface 58 . For purposes later described herein, the sloping top and bottom side walls 54 , 56 have rear portions 54 a , 56 a that rearwardly extend past the top and bottom edges of the concavely curved rear end surface 58 of the tooth point 16 . [0017] The adapter 14 is operatively mounted on the front edge section 12 a of the bucket lip 12 by placing the lip section 12 a in the adapter cavity 28 and then securing the top and bottom adapter legs 24 , 26 to the lip section 12 a in a suitable known manner not pertinent to the present invention. Tooth point 16 is mounted on the adapter 14 by inserting the adapter nose 32 into the point pocket 60 , so that the entire lateral periphery of the inserted nose 32 is enveloped by the tooth point 16 , and then inserting the connector pin 18 through the aligned tooth point openings 62 and the adapter nose opening 46 . As illustrated, the diameter of the connector pin 18 is somewhat less than the horizontal widths of the tooth point openings 62 . In this manner, the pin 18 is protected against the imposition of rearwardly directed tooth point loads as the point/adapter interface areas begin to wear away prior to tooth point replacement. [0018] With the tooth point 16 mounted on the adapter 14 in this manner, the front end surface 40 of the adapter nose tip portion 34 abuts the forward end surface 61 of the point pocket 60 , and the concavely curved rear end surface 58 of the tooth point 16 slidingly and complementarily abuts the identically curved convex front end surface 30 of the adapter base 20 along essentially the entire extent of the curved tooth point surface 58 . The rearwardly projecting portions 54 a , 56 a of the top and bottom walls 54 , 56 of the tooth point 16 respectively overlap and shield from abrasion front top and bottom exterior surface portions of the adapter base 20 . For a purpose later described herein, the rearwardly projecting wall portions 54 a , 56 a (which function as abrasion shield structures) are spaced outwardly apart from their underlying surface portions of the adapter base 20 and form gaps 64 therewith. [0019] Although the adapter nose 32 and the point pocket 60 have generally complementary configurations, the point pocket 60 is slightly laterally oversized relative to the adapter nose 32 in a manner such that a small interior pocket surface lateral clearance 66 extends around the inserted adapter nose tip portion 34 , and a somewhat larger interior pocket surface lateral clearance 68 extends around the balance of the inserted adapter nose 32 . Representatively, but not by way of any limitation, the width of the lateral clearance 66 is approximately 0.030″, and the width of the lateral clearance 68 is approximately 0.060″. As will be readily appreciated by those of ordinary skill in this particular art, this designed-in lateral clearance between the adapter nose 32 and the interior surface of the tooth point pocket 60 is in sharp contrast to the snug lateral abutment conventionally provided between a tooth point pocket and an adapter nose operatively inserted therein. [0020] This unique lateral clearance between the adapter nose 32 and the interior side surface of the point pocket 60 , coupled with the sliding engagement between the complementarily curved and slidingly abutting adapter base and tooth point surfaces 30 and 58 , permits the tooth point 16 to pivot upwardly and downwardly through a limited vertical arc, as indicated by the arrows 70 , relative to the adapter nose 32 about the horizontal axis A 3 during excavation operations. During this limited pivotal movement of the tooth point 16 , the tooth point surface 58 slides along the corresponding adapter base surface 30 , and the tooth point openings 62 are circumferentially shifted relative to opposite end portions of the pin 18 . [0021] The degree of clockwise and counterclockwise pivoting of the tooth point 16 relative to the adapter nose 32 is respectively limited by the abutment of a top point pocket interior surface area with the top side 36 of the adapter nose tip portion 34 , and by the abutment of a bottom point pocket interior surface area with the bottom side 38 of the adapter nose tip portion 34 . The gaps 64 between the rearward abrasion shielding extensions 54 a , 56 a on the tooth point 16 and their underlying adapter base surfaces prevents the extensions 54 a , 56 a from undesirably being brought into forcible contact with the adapter base 20 during this designed-in limited pivotal movement of the tooth point 16 and the adapter nose 32 . [0022] During excavation operations, rearward digging forces imposed on the tooth point 16 are transmitted from the front pocket surface 61 to the front end surface 40 of the stabilizing tip 34 , with the reactive force being borne by convexly curved adapter base surface 30 which is pivotally and slidingly engaged by the correspondingly curved tooth point surface 58 . This positioning of the reactive force directly on the adapter base 20 gives the assembly 10 a desirable strength advantage compared- to conventional tooth point/adapter assemblies in which such reactive force is borne by the less massive adapter nose portion of the assembly. [0023] The unique lateral clearance 66 , 68 extending around the adapter nose 32 advantageously prevents the adapter nose 32 , in response to rearwardly directed digging forces imposed on the tooth point 16 , from wedging into and elastically deforming the tooth point 16 in a manner causing the tooth point 16 to be frictionally locked onto the adapter nose 32 such that removal of the tooth point 16 from the adapter nose 32 becomes an inordinately difficult task. [0024] As will readily be appreciated, the relatively small tooth point 16 functions as a replaceable wear member for the adapter nose portion 32 of the much larger adapter portion 14 of the overall assembly 10 . However, the principles of the present invention are not limited to a tooth point/adapter assembly, and may be advantageously employed in a variety of other types of excavation assemblies in which a wear member is mounted on another excavation structure for limited pivotal movement relative thereto. [0025] Also, while the tooth point 16 has been representatively illustrated and described herein as being pivotable relative to the adapter nose 32 about the horizontal axis A 3 , the tooth point 16 (or another wear structure such as an intermediate adapter connected to the adapter 32 ) could also be pivotable about a differently oriented axis. Furthermore, the illustrated stabilizing adapter nose tip 34 could be shortened or eliminated, if desired, the result being that the pivotal stop surface area on the adapter nose 32 , which functions to limit the pivotal movement of the tooth point 16 relative to the adapter 14 would be shifted rearwardly along the adapter nose 32 . [0026] Moreover, while the front surface 30 of the adapter base 20 has been representatively illustrated and described herein as having a forwardly convex curvature, and the rear surface 58 of the tooth point 16 has been representatively illustrated and described herein as having a forwardly concave curvature complementary to the curvature of the adapter base surface 30 , it will be appreciated that these curvatures could be reversed, if desired, such that the front surface 30 and the rear surface 58 were respectively provided with complementary concave and convex curvatures. [0027] The foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims.	An excavating adapter/tooth point assembly has an interfit configuration in which the front end surface of the adapter base has a curved front surface portion that slidingly and complementarily engages a facing curved rear end surface portion of the tooth point. The adapter nose received in the tooth point pocket is somewhat smaller in cross-section that the pocket to permit a limited vertical rocking movement of the point relative to the adapter nose, about a connector structure captively retaining the point on the adapter nose, while transferring rearwardly directed excavating loads on the point to the curved sliding adapter/point interface area. Top and bottom sides of a rear end portion of the point have curved ear projections which extend rearwardly and outwardly along the adapter base and function as built-in wear guards that protect underlying surface portions of the adapter base.
You are an expert at summarizing long articles. Proceed to summarize the following text: RELATED APPLICATION [0001] This application is a continuation-in-part of U.S. application Ser. No. PCT/US09/54630 filed on Aug. 21, 2009. This application also claims priority to U.S. Provisional Application No. 61/430,331 filed on Jan. 6, 2011. FIELD OF THE INVENTION [0002] The invention relates to the field of ladders and scaffolding, particularly ladders with platform steps and accessories that attach thereto. The invention also relates to creepers and hand carts. BACKGROUND OF THE INVENTION [0003] The ladder of the present invention is a platform step ladder designed to allow the ladder to be positioned at various inclinations, while allowing the platform steps to remain generally parallel to the ground. In another configuration, the platform steps of the ladder can align to form a generally or substantially continuous planar surface to allow the ladder to be used as a platform or as a ramp. In alternate embodiments, the ladder of the present invention can include mechanisms to allow the ladder to be locked or secured at a particular inclination. Additionally, the ladder can include a wheeled base to allow the ladder to be moved from place to place. In further embodiments of the invention, the ladder is constructed to accept accessory bars to permit the attachment of accessories such as wheels, to allow the ladder, when in the platform configuration, to be used as a creeper. Other accessory bars include wheels and a handle to allow the platform to be used as a cart. Other accessory bars include hooks or pads to be used on the top end of the ladder when the ladder is deployed. SUMMARY OF THE INVENTION [0004] The ladder base consists of a rectangular frame with four forward attachment brackets and four rear brackets extending upwards from the base. The ladder frame includes a plurality of ladder frame rails and a plurality of steps located between the rails. Pairs of ladder frame rails are connected by support or pivot rods, similar in form to the rungs of a conventional ladder, to form a front frame and a rear frame. In the preferred embodiment, the support rods are welded to the frame rails. In alternate embodiments, the support rods fit through apertures in the rails and are secured to the rails by welds, mechanical fasteners such as threads and nuts, or cotter pins. While the support rods may be free to rotate with respect to the ladder rails, it is not necessary. The platform or steps of each ladder link the front frame and the rear frame. The ladder frame rails attach to the brackets of the base with pivot rods welded to the ladder frame rails. In other embodiments, other means of attachment, such as rivets, nuts and bolts, pins, or other fasteners can be used to pivotably attach the rails to the base. [0005] The steps or platforms of the ladder are free to rotate about or hinge around the support rods connecting the ladder rails. The pivot arrangement may be improved by means of fitted bushings. The steps are made of a center brace, two end brackets and three support brackets with a tread plate on the top side of the bracket weldment. The steps are secured to the frame with support or pivot rods inserted through the steps and welded to the frame rails. At the ends of the ladder frame are four locking brackets that engage the lock pins to secure the assembly in the ramp or scaffold function. [0006] When assembled, the ladder is adjustable so that it may be inclined at different angles with respect to the ground while allowing the platform steps to remain generally parallel to the base of the assembly, which is intended to be placed on the ground. As the ladder frame rails rotate with respect to the base, the steps and base act to keep the four rails parallel at any pitch angle. When the ladder is collapsed, the steps line up to form the surface of a scaffold or ramp. [0007] At or near the top end of the ladder frame, various attachments can be added for certain applications, allowing the ladder to attach to or interface with another object, such as a rail on the side of a farm implement or a receiver mounted on a flatbed trailer. Of course, the ladder can be deployed free-standing against a wall or other structure, or attachments such as hooks, a roller and track configuration or a bracket assembly for securing to a flatbed type semi trailer. Pneumatics or hydraulics could also be implemented to actuate one pair of the rails to quickly flatten the ladder to make a ramp or slide. In other embodiments, supports or jacks between the ladder rails and the ground or other reference surface can be used to secure the ladder at a particular inclination. [0008] The ladder is also constructed to receive accessory bars that allow features to be selectively attached and removed from the ladder. Specifically, the accessory bars equipped with a headrest and swivelable wheels, disclosed herein allow the ladder, when in the stowed or platform configuration, to be used as a creeper for accessing height restricted areas such as the underside of a trailer, car, or truck. Other accessory bars can include non swivelable wheels such as those mounted on an axel extending across the accessory bar or also included an upright handle that is selectively locked in an upright or first position, but allowed to pivot between the upright and horizontal position when unlocked. Providing the wheels and handle allow the ladder, when in the stowed or platform configuration, to be used a hand cart or trailer. [0009] The ladder of the present invention can be described as having three main components: [0010] 1) Ladder frames [0011] 2) Ladder base and steps [0012] 3) application/attachment assembly 1) Ladder Frame: [0013] Components of ladder frames include a plurality of rails, and a plurality of support rods. In the preferred embodiment, four rails are used. The support rods connect pairs of rails, in a fashion similar to ladder rungs, to form what are akin to two normal ladders. The spacing of the support rods can vary depending upon the application of the ladder. The spacing of the support rods on each frame will be similar, so that the steps linking the two ladder frames will maintain the same angle with respect to each other. The two ladder frames are linked by the base and steps, the support rods pivotably or hingedly supporting the platform steps. Components of ladder frame can be assembled in a manner that when in an unfolded working position at a 45 degree pitch, ladder will give the appearance of a flight of stairs. [0014] In addition, when the ladder frame is in a folded position or storage position, it can be used as a ramp or scaffolding, as the steps of the ladder fold to lie in a generally planar arrangement between the rails. 2) Ladder Base and Steps: [0015] The bottom of the ladder frame pivotably attaches to brackets on the ladder base. The base includes brackets that are offset in height. The offset allows one set of frame rails to overlie another set of frame rails, allowing the ladder to fold and form a platform or scaffold surface. Once the frame is attached to base and steps are attached to the support rods, the ladder may be set at different angles, and the steps will remain parallel to the base. While the brackets may be placed at the corners of the base, it is advantageous to have the based extend some distance in front of the front set of brackets. The extension of the base provides leverage to resist the torque that may be generated by loads on the steps of the ladder when the ladder is in use. The base may also include handles on its periphery to allow ease of carrying. The handles can also provide the user a convenient handhold when deploying or stowing the ladder when the ladder is used in a track mounted configuration. [0016] The ladder base will also provide secure footing for the ladder assembly in addition to having a locking device to be used when ladder is in a folded down position for use as a ramp or for storage. The ladder base is optional, and a ladder consistent with the invention described herein can be constructed without a base. In such an embodiment, the locking mechanism to lock the two ladder frames together is located on the steps, or on the rails. [0017] In a ladder that does not have a base, the steps link the two ladder frames. In such an embodiment, the ends of the rails may include height adjustment devices to assist in leveling the ladder frames on uneven ground. [0018] The linkage provided by the base and steps allows the ladder of the present invention to be used at an infinite number of pitches between 0-90 degrees, since the angle formed by the rails with respect to the ground may change, although the platform steps remain parallel to the ground and to each other. When viewed from the side, the frame rails and the steps form a parallelogram. [0019] The ability to keep the steps parallel is of benefit if the top of the ladder is fixed to a piece of machinery, such as a farm implement or flatbed trailer. The ladder can be deployed to varying levels, such as the ground or a pickup truck bed, while the steps remain parallel to the ground in either instance. [0020] Additionally, the ladder, when in folded so that the ladder rails lie against one another, or so the base and the rails are parallel, the steps form a generally planar surface, so that the ladder can be uses as a platform or a ramp. 3) Application/Attachment Assembly: [0021] In some applications, the top end of ladder simply rests freely against the work area. However, the ladder of the present invention can accommodate optional attachments at the top end of ladder, allowing the ladder to be more securely fixed to an object or work area. Such attachments described herein allow mounting the ladder to all types of machinery, vehicles, and buildings etc. Application/attachment assemblies may consist of one or a combination of the following. 1) Hooks attached to top of ladder may be used to secure ladder to a rod on any given fixed point. 2) Square, rectangular, round tubing or post material or any combination may be pivotably attached to the ladder, allowing the post to be placed in a suitable receiver on the work area. An example of such a receiver would be a vertical hole, receiver, or stake pocket in the frame of a flatbed trailer; 3) Any other form of receiver that will firmly secure ladder to any fixed point; 4) pads to protect any surface that the ladder rests against; 5) wheels. [0022] The above assemblies may also be used on both of ladder ends so as when ladder is in a closed or folded position, it can be used as a form of scaffolding or ramp between two fixed points. In particular, the attachment of wheels and a headrest to the ladder in the folded configuration will allow the structure to be used as a creeper or dolly. The attachment of a handle would allow the structure to be used as a cart. [0023] The additional assemblies or accessories may be placed on accessory bars that are selectively attached and detached from receivers on the ends of the ladder. [0024] The ladder assembly may be made of one or more of the following materials; aluminum, steel, fiberglass, wood, composites, or any other material of suitable strength and durability. [0025] The length of ladder assembly can be as long as desired, but also remaining within an acceptable standard of safety. Lengths will be determined according to application. [0026] The width of ladder can also vary according to application and desire while remaining within a standard of safety. [0027] Step construction: standard placement of step assembly within ladder frame is preferred to be 12″ center to center as it is on conventional ladders from rung to rung. This can also deviate from standard if desired. Step assembly depth or length shall also be as desired. If ladder is to be used as a ramp it is preferred that the depth/length of the steps shall be great enough to allow steps to meet or nearly meet end to end while in folded position so as to form a generally planar, nearly continuous surface. Step assembly depth/length can be decreased if desired to allow more spacing between the steps or individual platforms when the ladder is folded. BRIEF DESCRIPTION OF THE DRAWINGS [0028] FIG. 1 is a perspective view of the ladder in a deployed configuration. [0029] FIG. 2 is a perspective view of the ladder in a stowed or scaffold. configuration. [0030] FIG. 2 a is a close-up partial perspective view of a portion of FIG. 2 . [0031] FIG. 3 is an underside partial perspective view of a representative step assembled on the ladder. [0032] FIG. 4 is a top perspective view of a step. [0033] FIG. 5 is a top partial perspective view of the base and bottom step assembled on the ladder, the foot support surface of the step removed. [0034] FIG. 6 is a top perspective view of a base. [0035] FIG. 7 is a top partial perspective view of the top step assembled on the ladder. [0036] FIG. 8 is a top partial perspective view of the top of the ladder with a staker. [0037] FIG. 9 is a top partial perspective view of the top of the ladder attached to rollers and track. [0038] FIG. 10 is a top perspective view of a base having stability extensions and handles. [0039] FIG. 11 is a perspective view of a ladder with supports to adjust the inclination of the ladder. [0040] FIG. 12 is a perspective view of a ladder with supports to adjust the inclination of the ladder and a handrail. [0041] FIG. 13 is perspective view of a ladder with supports to adjust the inclination of the ladder, a handrail, and a wheeled base. [0042] FIG. 14 is a partial perspective view of a linkage for adjusting the inclination of the ladder. [0043] FIG. 15 is a top plan view of an infinitely adjustable linkage mounted on the ladder. [0044] FIG. 16 is a side elevational view of an infinitely adjustable linkage mounted on the ladder. [0045] FIG. 17 is a partial perspective view of a ladder fixed to an object and having adjustable actuators to adjust the level of the steps. [0046] FIG. 18 is a side view of a ladder rail having a height adjuster. [0047] FIG. 19 is a perspective view of a shortened ladder in the deployed position with the base side members having receivers for receiving accessory bars. [0048] FIG. 20 is a perspective view of a ladder in the stowed position with a first unmounted accessory bar including a headrest and swivelable wheels and a second unmounted accessory bar having swivelable wheels. [0049] FIG. 21 is a perspective view of a ladder in the stowed position with mounted accessory bars. [0050] FIG. 22 is a perspective view of a ladder in the stowed position with a first mounted accessory bar having a lockable and pivotable handle positioned in an upright position and wheels, and a second mounted accessory bar having wheels. [0051] FIG. 23 is a perspective view of a ladder in the stowed position with a first mounted accessory bar having a lockable and pivotable handle and wheels, and a second mounted accessory bar having wheels. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0052] The ladder 10 includes four ladder rails 15 a - d , each having a top end 16 a - d and a bottom end 17 a - d . Each rail 15 a - d is pivotably connected at their bottom ends 17 a - d to a base 18 . In the preferred embodiment, the rails 15 a - d are square metal tube stock, although other materials, such as solid stock, I beams, angle iron, channel stock, fiberglass, composites, and lumber, could be utilized to form the rails. It is not necessary that the rails be of tube stock. While the rails are square in the preferred embodiment, they may also be of any convenient shape. The length of the rails can vary, although for flatbed trailer applications, it is preferred that the rails be at least 60 in length. It is preferred that at least two of the ladder rails extend 48 inches above the top most step, here step 20 a, to provide for a hand grip when a person is on the top most step 20 a. [0053] Each rail 15 a - d is pivotally attached to a plurality of steps 20 a - g positioned at generally equal intervals between the rail top ends 16 a - d and the rail bottom ends 17 a - d . The intervals closely match the length of the steps 20 , so that the steps form a nearly continuous surface when the ladder 10 is in the folded or ramp configuration shown in FIG. 2 . In the preferred embodiment, the steps 20 are seven in number and are approximately 12 inches square. [0054] The steps 20 a - g are pivotally attached to the rails 15 a - d by support rods 25 a - n that extend between pairs of rails, much like the rungs of a traditional ladder. So constructed, the ladder has a first frame 11 and a second frame 12 linked together by the plurality of steps 20 a - g . In the embodiments shown in the figures, support rods 25 h - n connect rails 15 c and 15 d to form the first frame 11 . The support rods 25 a - g connect rails 15 a and 15 b to form the second frame 12 . The support rods 25 a - n fit through apertures in the rails 15 a - d and are secured at their terminal ends by welding the support rod ends to the outside surface of the rail. It is also possible to weld the rods at any area in which the rod and the rail contact each other. In other embodiments, the support rods need not go through apertures in the rails, but may be attached to brackets attached to the exterior surface of the rails, or attached to the surface of the rails themselves without the need for brackets. One skilled in the art will recognize that there are may ways to attach the rods to the rails so that the rods will support the steps 20 a - g and allow the steps to move relative to the rails as the angle of the rails with respect to the ground is changed. [0055] In other embodiments, the steps 20 a - g are fastened to the rails 15 a - d by fasteners, such as nuts and bolts, rivets, pins, or other fasteners known in the industry. In such embodiments, the steps 20 a - g in conjunction with the fasteners act to connect the rails to each other. [0056] The steps 20 a - g are shown in detail with reference to a single step in FIGS. 3-5 . The steps 20 are generally 12 inches square, but one skilled in the art will recognize that the dimension of the steps may be change to suit the application. Each step includes a frame 21 formed by a pair of side members 22 a and 22 b spaced apart by cross members 23 a - c . The members are preferably joined by welding. A tread plate or other foot support surface 28 overlies the frame 21 . [0057] The side members 22 a and 22 b include apertures to accept a support rod 25 . The side members 22 a and 22 b can be “L” shaped to allow pairs of apertures 26 a - b and 27 a - b to be offset vertically. The vertical offset is generally the same as the height of a rail, the offset allowing the rails to lie against or in close proximity to one another when the ladder 10 is in the folded, collapsed, storage, or ramp configuration shown in FIG. 2 . In other embodiments, be side members can be straight, and include downwardly extending brackets to produce the offset. A bushing 121 a - d may be placed in the apertures to allow the step 20 to rotate about the rod 25 in an improved fashion. The steps may be spaced apart form the rails by spacers that fit over the rods, the spacers having a diameter larger that the diameter of apertures in the brackets attaching the steps to the rods so as to keep distance between the rails and the steps. [0058] In alternate embodiments, the brackets are planar metal members with an aperture to accept the rods 25 , or other fastener, and thereby allow the step 20 to rotate with respect to the rod 25 or other fastener. In alternate embodiments, the bracket 30 may be fixed to the fastener, rod 25 , or other member, and the fastener allowed to rotate with respect to the rail 15 . The apertures in the brackets are offset vertically by a distance equal to the overall height of one rail. The bracket will also allow a surface for welding the support rod in a metal construction. [0059] The offset of the apertures 27 a - b and 27 a - b in the side members 22 a and 22 b is approximately the width of a side rail 15 from front to back. In the preferred embodiment, the offset is approximately 1.25 inches. This offset allows the ladder to form a platform when in the stowed configuration by allowing the rails 15 b and 15 c to lie in close proximity or against each other, as shown in FIG. 2 . Thus, the offset is controlled somewhat by the width of the rails and the placement of the apertures in the rails. [0060] In other embodiments, a step 20 may be constructed out of a single piece of material. Such material may include metal, wood, plastic, composites, or any other material known to one skilled in the art. For instance, the step 20 may be made as a blow-molded piece of plastic. Such a step may include reinforcing ribs made of plastic or some other material such as metal, but may not necessarily need such reinforcement. The single piece step may include a first set of apertures and a second set of apertures vertically off-set from the first set of apertures. [0061] The base 18 of the preferred embodiment includes a frame composed of four side members 45 a - d connected to form a rigid structure. The base 18 is preferably a welded fabrication consisting of two end tubes 45 b and 45 d and two side tubes 45 a and 45 c of the same stock size as the rails 15 a - d . One skilled in the art will recognize that other sizes and materials may be used to construct the base 18 . The end tubes 45 b and 45 d and the two side tubes 45 a and 45 c form a frame that is generally rectangular with dimensions allowing that the rails of the first frame 11 will be separated by at least the overall width of one step assembly, and is the foundation for the hinge brackets. [0062] The hinge brackets 50 a - d connect the four rails 15 a - d with a minimal amount of free-play, but to allow for free rotation. The hinge brackets holding the first frame 11 are preferably spaced apart on the base 18 from the brackets holding the second frame 12 at the same distance that horizontally separates the apertures on the side member 22 . The hinge brackets 50 a - d are generally upstanding planar members that include apertures 56 to accept the connecting rods 25 . The apertures are vertically offset by approximately the same distance as the apertures 26 a and 27 a of the steps 20 in order to allow the ladder 10 to fold into a generally flat configuration. In such a folded configuration, the steps 20 a - g form a support surface. When in a folded configuration the first frame 11 lies over the second frame 12 . In the folded configuration, the first frame 11 is displaced from the second frame 12 in the horizontal direction by the horizontal distance between the apertures 26 and 27 of the step 20 side member 22 . [0063] It is preferred that there is structure to secure the ladder 10 in the folded or platform position shown in FIG. 2 . In the preferred embodiment, the locking structure secures the first frame 11 to the second frame 12 . On skilled in the art will recognize that other components can be secured together to maintain the ladder 10 in the platform or folded configuration. [0064] As shown in FIG. 2 a , the locking structure includes a lock plate 60 with a slot 61 to engage a locking pin 62 and a hole to attach to one end of one support rod 25 . Such structure can be placed at or near the ends of the rails on both sides of the ladder 10 , as shown in FIGS. 1 and 2 . The lock plate 60 is a generally planar member. The slot 61 is offset from the hole a distance equal to the overall height of one rail 15 , and is shaped so that the slot 61 is a small section of a circular arc of a radius that is equal to the overall height of one rail 61 . This will allow the lock plate 60 to engage the lock pin 62 smoothly over an angle of approximately 16 degrees. In this arrangement, the support rod 25 g is not fastened to the bracket 50 a or rail 15 , but directly to the lock plate 60 itself allowing for free rotation of the entire length of the support rod 25 g. [0065] The top end 16 a and 16 b of the rails 15 a and 15 b may include accessories to allow the ladder 10 to attach or interact with work surfaces or other objects. The top ends 16 a and 16 b need not be the extreme terminus of the rails 15 , but are generally beyond the midpoint of the rails. The top ends 16 a and 16 b may include hooks 70 a and 70 b . The hooks 70 a and 70 b may be formed as an integral part of the rails 15 a and 15 b, or be separate components attached to the rails by welding, fasteners, or other means or structures known in the art to attach components together. [0066] The top end may also include brackets 72 a and 72 b to accept a generally “T” shaped stake or post 75 . The post 75 is a structure that allows the ladder to be fixed to another structure such as a flatbed trailer. The post 75 includes a portion that is affixed to the other structure and a second portion that is allowed to rotate with respect to the rails 15 of the ladder 10 . In the preferred embodiment the post 75 includes a horizontal portion that is free to rotate in the brackets 72 , thus allowing the post 75 to rotate with respect to the rails about an axis that is parallel to the plane of any one of the steps 20 a - g . The post 75 has a downwardly extending appendage 76 that can be accepted by a receiver 90 , such as a hole in the frame of a flatbed trailer. One skilled in the art will recognize that other receivers can be used to accept the post 75 and that other configurations can be used for the r post such that the post can be fixed to an object and allow the ladder to rotate about the post 75 . [0067] The top ends 16 a and 16 b may include wheels 80 or other rolling members. The wheels 80 can interact with track 78 mounted to a work surface such as a piece of heavy equipment or flatbed trailer. The track is preferably mounted in a horizontal position, with an end 79 presented or exposed to a user. The track has a length that is preferably equal to the length from the place on the rail that the wheel is mounted to the base of the ladder. This arrangement allows the ladder to be placed in its flat or stowed configuration and then slid along the tracks 78 to be stowed. In such a stowed configuration, the ladder 10 can also be used as a work platform, as the tread plates 28 of the steps 20 a;g will form a generally planar surface. [0068] In an alternate embodiment shown in FIG. 10 , the base 118 can include an extension 120 that extends in front of brackets 150 c and 150 d. Described another way, the brackets are not placed at the corners of the base 18 , but are instead displaced from the corners. The extension 120 may include handles 160 a and 160 b. Handles 160 a and 160 b may be placed on the sides of the base 118 . In other respects, the base 118 is similar to base 18 . [0069] In alternate embodiments as shown in FIGS. 11-13 , the ladder 210 can be supported by supports 290 a and 290 b. The supports have one end pivotably attached to the ladder frame rails 215 a and 215 b, preferably at the rail top ends to improve leverage. However, they may be positioned anywhere along the length of the rails, or may be pivotably attached to any other members of the ladder frame. [0070] The supports 290 a and 290 b can be adjusted to vary the inclination of the ladder 210 . The supports 290 a and 290 b can be adjusted by allowing first support members 291 a and 291 b to slide within the second support members 292 a and 292 b. The sliding members may be fixed in place by a pin placed in apertures, locking collars, or other means known to secure sliding members. In other embodiments, the supports may be pneumatically or hydraulically operated. [0071] The alternate ladder may include a handrail assembly 280 shown in FIGS. 12 and 13 . The handrail assembly 280 includes a first upright or stanchion 281 fixably mounted to the uppermost step, and a second upright or stanchion 282 fixably mounted to the base 210 . The stanchions are pivotably connected to a handrail 285 that extends there between. [0072] in other embodiments, the ladder, such as the ladder 210 , can be mounted on a wheeled frame 300 , to allow the ladder to easily be moved from place to place. The wheeled frame 300 includes wheels 310 mounted near the corners. The frame includes brackets 395 to pivotably mount the supports 290 a and 290 b. [0073] In any of the ladder embodiments, the ladder may be locked in a particular inclination using a linkage 370 between the ladder side rails such as between 15 a and 15 d or 15 b and 15 c. Such linkage links the first frame 11 to the second frame 12 . As shown in FIG. 13 , the linkage 370 is pivotably attached to side rail 15 c, and extends to side rail 15 b, where one of a plurality of slots 375 engages a pin 380 to selectively lock the ladder inclination. One skilled in the art will recognize that other mechanisms or structures can be used to lock or otherwise secure the inclination of the ladder. [0074] An alternative linkage that allows infinite adjustment is shown in FIG. 15 . The alternate linkage includes a first slotted linking member 471 and a second slotted linking member 472 , each liking member having a slot to sunning the length of the linking member. The linking members 471 and 472 are arranged on either side of rails 15 a and 15 d so that the rails are between the linking members 471 and 472 and the slots of the linking members are aligned with each other. The linking members 471 and 472 are secured to the rails 15 a and 15 d by fasteners such as nuts 410 and bolts 420 . Other fasteners can be used so long as the linking members are allowed to pivot with respect to the rails 15 a and 15 d. In the preferred embodiment, the connection between the linking members 471 and 472 and rail 15 a allows pivoting, but does not allow the fastener to move along the slot. Thus the ladder rail 15 a is translationally fixed with respect to the linking members 471 and 472 . Rail 15 d is not translationally fixed with respect to the liking members 471 and 472 , and the fastener is allowed to slide in the slots of the linking members 471 and 472 . In order to restrain or limit the translational movement, a stop 480 is placed in the slot. The stop 480 can be a nut and bolt. In the preferred embodiment, the stop 480 is a cam action lever clamp that allows the user to selectively secure and unsecure the stop at a position in the slot. The cam action lever clamp includes a stud or post 481 that is inserted in the slot and a cam action lever 482 that attaches to the post 481 . A spacer 484 is paced about the post 481 to allow the clamp to grasp the linking member 472 between the lever 482 and the spacer 484 , and linking member 471 between the post 481 and the spacer 484 . To improve friction, the inside surfaces of the linking members 471 or 472 or the spacer 484 may include surface features such as ridges, grooves 485 , or other structures to increase friction. [0075] In another embodiment, shown in FIG. 17 , the second frame 12 is fixed or attached to another object so that the first frame is allowed to pivot about the attachment. In the embodiment shown in FIG. 17 , the support rod 25 g is fixed in place so that the second frame 12 can pivot with respect to it, but is fixed in other degrees of freedom of movement. The first frame is pivotably connected to adjustable actuators 700 a and 700 b . The adjustable actuators 700 a and 700 b are fixed to an object such as the object fixed to the second frame 12 , or to yet another object such as the ground. The adjustable actuators are then used to adjust the angle of the steps 10 by moving the first frame 11 with respect to the fixed second frame 12 . [0076] The ladder 10 may be constructed without the base 18 . In such an embodiment, it may be useful to have the bottom ends 17 c and 17 b of the rails 15 c and 15 d of the first frame 11 be slightly longer than the bottom ends 17 a and 17 b of the rails 15 a and 15 b of the second frame. The extra length will depend upon the vertical offset used on the steps 20 . The additional length allows for the steps to be level when the ladder 10 without the base 18 is placed on level ground. The vertical off set is typically the height of one rail 15 , as previously discussed. [0077] The bottom ends 17 a - d of the rails 15 a - d may also include height adjusters. A representative height adjuster 750 is shown in FIG. 17 . While only one adjuster is shown, it may be applied to any of the rails 15 a - d . The adjuster 750 operates by allowing an adjuster support member 751 to slide within the rail 15 . The support member is sized 751 to fit within the rail 15 . The support member 751 and the rail are fixed in place by a pin placed in an aperture 752 in the rail 15 , and in one of a plurality of apertures 755 . In other embodiments, locking collars, or other means known to secure sliding members may be used. In other embodiments, the supports may be pneumatically or hydraulically operated. When the ladder 10 is used without the base 18 , the adjuster support member 751 will contact the ground or other surface. When used with a base 18 , the adjuster support member 751 may include an additional aperture 760 for attachment to the base 18 in the place of the bottom ends 17 a - d of the rails 15 a - d. [0078] With reference to FIGS. 19 through. 24 , another embodiment of the ladder 10 is shown. In this embodiment, the ladder 10 includes structure to allow the ladder 10 to be converted into a creeper or a cart when in the platform configuration by the attachment of accessory bars 600 to the rails 15 and base 18 of the ladder 10 . With the use of accessory bars 600 placed in suitable receivers on the ladder 10 , wheels, pads, hooks, or other structures that may be used with the ladder in the ladder 10 or in the platform configuration can be selectively attached or removed from the ladder 10 . In other embodiments, the accessories, such as wheels, pads, hooks, or other structures may be placed on posts that connect to only one receiver. [0079] As shown in FIG. 20 , the accessory bars 600 attach to the ends 16 a and 16 b of the ladder rails 15 a and 15 b or to the base 18 . When the ladder rails 15 a and 15 b and base 18 are made of tube stock, the ends of the ladder rails 16 a and 16 b are open to receive the accessory bars 600 . Being open, they form receivers to receive the accessory bars 600 . [0080] When the ladder rails 15 a and 15 b are used to receive the accessory bar 600 , they may only do so when the ladder 10 is in the platform configuration, thus exposing the first ends 16 a and 16 b. When the ladder is deployed, the base 18 prevents the first ends 16 a and 16 b from receiving the accessory bar 600 . [0081] When other materials are used for construction of the ladder 10 such that the ends are not open to form receivers the ends 16 a and 16 b and base 18 are equipped with receivers, such as lengths of open square tube stock attached to the ladder rail ends 16 or the base 18 . The accessory bars 600 are sized to fit into the open ends of the tube stock. The accessory bars 600 are preferably held in place on the ladder by removable locking pins 630 that fit into holes in the ends of the ladder rails 16 a and 16 b and base 18 . The accessory bars 600 have corresponding holes that align with the holes in the ladder rails 16 a and 16 b and base 18 when thee accessory bars 600 are in place, allowing the accessory bars 600 to be selectively secured. One skilled in the art will recognize that other structures can be used to selectively attach and remove the accessory bars 600 . [0082] FIGS. 19-24 show a ladder 10 of the present invention, but one that is shorter than the one shown in FIGS. 1-17 . In this embodiment, which is merely an example, the ladder 10 has for steps 20 a - 20 d. The base 18 of the ladder is also modified, but the ladder 10 is otherwise similar in construction and components. The base 18 of the ladder 10 of the embodiment shown in FIGS. 19-24 also has the tube members 45 forming the base 18 , the end tubes 45 b and 45 d placed so that the open ends 640 of the end tubes 45 b and 45 d _face towards the front of the ladder 10 rather than the sides. In such a position, the open ends 640 form receivers for the receipt of the ends or posts 620 of the accessory bars 630 . Such a base 18 configuration could also be used on the Ladder 10 shown in FIGS. 1-17 as well. [0083] The accessory bars 600 in the basic form include a cross member 610 and two posts 620 . In the preferred embodiment, the cross member 610 and posts 620 span the width of the ladder 10 from ladder rail to ladder rail, or across the width of the base 18 for an accessory bar 600 that is attached to the base 18 . In the preferred embodiment, the ladder rails 15 are positioned at the same width as the base 18 , so an accessory bar 600 that fits the base 18 will also fit the ladder rails 15 . [0084] The posts 620 are positioned on the cross member 610 so that the posts 620 will fit into the ends of the ladder rails 16 a and 16 b, or into receivers on the ladder rails 15 . The posts 620 extend from the cross member 610 approximately 5 to 8 inches and are preferably positioned at right angles to the cross member 610 . One skilled in the art will recognize that the posts 620 can be of different lengths and need not be of the same length. The length of the post 620 also need not be 5 to 8 inches, and the length may be longer or shorter, although it is preferred that the posts 620 fit into the rails 15 , base 18 , or receiver for at least three inches so to provide stable and secure attachment. [0085] As shown in FIGS. 20 and 21 , the accessory bars 600 include pivoting wheels or casters 645 to allow the ladder 10 to be used as a creeper. The wheels 645 preferably are low profile and are positioned near the corners of the accessory bar 600 to allow for a more stable platform. One of the accessory bars 600 includes a headrest 650 . The headrest 650 is preferably attached by a bracket 647 to the accessory bar 600 that attaches to the base 18 . In the preferred embodiment, the bracket 647 elevates the headrest 650 from the accessory bar 600 so that the headrest 650 is positioned above the step 20 d when the accessory bar 600 is attached to the ladder 10 . In the preferred embodiment, the headrest 650 is thus displaced both vertically and horizontally from the position of the accessory bar cross member 610 . In such a case the headrest bracket 647 is “U” shaped. In other embodiments, the headrest bracket 674 is removable from the accessory bar 600 . In such a case, the accessory bar 600 is equipped with a receiver to receive the headrest bracket 647 . In other embodiments, the headrest bracket 647 is height adjustable to allow the height of the headrest 650 above the step 20 d to be adjusted. This may be accomplished by providing the headrest bracket 647 with a plurality of spaced apart apertures, and providing the headrest bracket receiver with a corresponding aligning aperture for the insertion and removal of a locking pin, similar to the arrangement use for the height adjustment of the ladder 10 and shown in FIG. 18 . [0086] While the headrest equipped accessory bar 600 has been shown as attached to the base 18 , the headrest equipped accessory bar 600 may also be attached to the ladder rails 15 a and 15 b at the opposite end of the ladder 10 . In such an instance, the non-headrest equipped accessory bar is attached to the base 18 . [0087] With reference to FIGS. 22-24 , the accessory bars 600 may be equipped with an axel 652 and larger non swiveling wheels 653 to convert the ladder 10 into a cart. Such an example is shown with accessory bar 602 . In the preferred embodiment, the axel 652 extends away from the sides of the accessory bar 602 . In other embodiments, one or all of the accessory bars 600 includes swivelable wheels 645 to allow easy maneuverability of the cart. For instance a first accessory bar 602 will include non swiveling wheels 653 on an axel 652 , and the other accessory bar 601 will include swivelable wheels 654 such as casters. In any of the cart embodiments, one of the accessory bars 600 will include a handle 660 . In the figures shown, the handle 660 is attached to the accessory bar 601 that includes swivelable wheels 654 . The handle 660 is pivotably attached to be placed in a secured upright position, and also be allowed to pivot downward when the locking mechanism is released. It is preferred that the handle 660 freely be allowed to pivot in the unlocked position to allow the handle 660 to be placed a varying heights when connected to a hitch 662 , as shown in FIG. 24 , for use of the ladder 10 as a cart that is towable by a tractor or other conveyance having a hitch 662 or other attachment point. [0088] The embodiments described herein are merely examples and are not meant to limit the scope of the invention.	A ladder having platform steps, the ladder being convertible between a deployed position for supporting a person or other load, to a storage, scaffold, or ramp position in which the steps lie in a generally planar arrangement. When deployed, the ladder steps remain parallel to each other and form a series of parallelograms with the rails of the ladder. The ladder is also capable of being locked or secured at various angles of deployment. The ladder further includes receivers to selectively receive accessories such as wheels, hooks, handles, or pads. The addition of accessories such as wheels allows the ladder in the storage position to be used as a creeper, dolly, or cart.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Patent Application 61/050,244 filed by the inventors herein on May 4, 2008, the disclosure of which is incorporated herein by reference. BACKGROUND [0002] The present invention relates to road vehicles used to repair and patch roadway surfaces, such as the filling of potholes or similar defects or concavities in asphalt-type pavements, and, more particularly, to roadway patching vehicles having a moveable boom mounted to their chassis for placement over the area to be patched and having a nozzle for dispensing various materials for implementing the patching function. [0003] Various types of wheeled vehicles have been developed to patch roadway surfaces, particularly for the filling of potholes of various shapes and sizes. Some of these vehicles carry a load of hot patching-material in a vehicle-mounted hopper with a rear-mounted chute through which the patching material is dispensed into the pothole; typically, one more workman are required remove dust and loose material from the potholes and thereafter guide the patch material(s) into the pothole and tamp the surface of the patch material to conform to the surface of the roadway. More recent vehicles use a forward-mounted boom that is controlled by hydraulic actuators to position a nozzle over the pothole. The operator of the vehicle controls a flow of pressurized air directed into the pothole to removed excess water, dust, and loose debris with a further controlled flow of emulsified asphalt and/or a mix of emulsified asphalt/rock aggregate for delivery into and for filling of the pothole. SUMMARY [0004] A road patching vehicle for patching potholes of various sizes and shapes includes a boom assembly pivotally mounted at or on the front of the vehicle with a nozzle mounted at or toward the forward end of the boom. Various hoses connect the nozzle to at least a source of pressurized air, a source of patching emulsion (such as an asphalt emulsion), and a source of a rock aggregate with the vehicle operator controlling the flows individually or in various combinations thereof to prepare and then fill the pothole or other road defect to effect a patch. The nozzle is mounted on a pivot or journal to allow controlled pivoting or tilting of the nozzle under control of the operator in at least one degree of freedom. In a variant of the preferred form, the nozzle is mounted for control pivoting or tilting under the control of the operator in at least two degrees of freedom. BRIEF DESCRIPTION OF THE DRAWING [0005] FIGS. 1 and 2 are respective opposite side views of a patching vehicle showing an adjustable boom at the forward end; [0006] FIG. 3 is a perspective view of the vehicle shown in FIGS. 1 and 2 ; [0007] FIG. 4 is a simplified schematic view of the patching materials flow system; [0008] FIG. 5 is a first side view of the boom assembly including a rock aggregate transfer hose; [0009] FIG. 6 is a second side view of the patching boom assembly, from the side opposite that shown in FIG. 5 , in which the rock aggregate transfer hose and various components associated therewith have been removed for reasons of clarity; [0010] FIG. 7 is a top view side view of the boom assembly of FIG. 6 ; [0011] FIG. 7 a is a close-up view of the nozzle end of the boom of FIG. 7 ; [0012] FIG. 8 is perspective of the nozzle assembly shown in FIG. 7 a; [0013] FIG. 9 is a side elevational view of the nozzle assembly of FIG. 7 a with selected components omitted for reasons of clarity; and [0014] FIG. 10 is a cross-sectional view of FIG. 9 showing the interior of the nozzle; [0015] FIG. 11 a is a variant of the boom assembly in which the nozzle assembly is rotated ninety degrees from that shown in FIGS. 7-7 a; [0016] FIG. 11 b is another variant of the boom assembly shown in FIGS. 7-7 a; [0017] FIG. 12 is a another version of the nozzle mount having two degrees of freedom; and [0018] FIG. 13 illustrates the manner in which the nozzle mount of FIG. 12 is controlled. DESCRIPTION [0019] An exemplary road patcher vehicle with a nozzle system in accordance with one embodiment is shown in left-side and right-side views in FIGS. 1 and 2 and in an isometric perspective in FIG. 3 and is generally designated by the reference character 20 ; the overall road patcher configuration shown is representative of vehicles manufactured by Schwarze Industries, Inc. of Huntsville Ala. 35811 under the model RP-005 designation. [0020] As shown in FIGS. 1-3 , the truck-based road patcher 20 includes a boom assembly 22 at its forward end, an aggregate hopper 24 located rearwardly of the vehicle cab, and an asphalt emulsion holding tank 26 (dotted-line representation) at the rear of the vehicle. The boom assembly 22 , which is preferably mounted toward or at the forward end of the truck chassis, is designed to pivot from a ‘stowed’ position in which the boom assembly 22 is parallel or near parallel to the front of the vehicle (and retained in a cradle 28 ) to and from a selected deployed position under control of a hydraulic cylinder 30 . Another hydraulic cylinder 32 controls the angular relationship of distal end of the boom assembly 22 with the surface of the roadway and thus controls the distance between the distal end of the boom assembly 22 and the roadway (dotted-line representation). Thus, the remote end of the boom assembly can be moved through a path over the roadway under the control of the hydraulic cylinder 30 and the elevation at the end thereof above the roadway controlled by the hydraulic cylinder 32 . The road patcher 20 includes a hydraulic pump/reservoir system (not specifically shown) for providing pressurized hydraulic fluid through various hoses and valves to various hydraulic cylinders, motors, actuators, etc. under the control of the vehicle operator, an electrical system for powering various actuators and related devices, and, additionally, an air compressor for supplying compressed air for various purposes. [0021] The road patcher 20 includes a discharge nozzle 36 , described more fully below, at the remote or forward end of the boom assembly 22 for discharging a flow of pressurized air, a flowable asphalt emulsion, and/or a mixture of the asphalt emulation and rock aggregate into or onto the roadway to effect patching. Various hoses, connectors, valves and the like connect to the nozzle 36 to the pressurized air source, the emulsified asphalt holding tank 26 , and the aggregate hopper 24 of which only the aggregate transport hose 38 is shown in FIG. 1 . [0022] As shown in simplified schematic form in FIG. 4 , the aggregate hopper 24 includes, in the preferred embodiment, a conveyor 40 for transporting aggregate to an aggregate feeder 42 into the rock transport hose 38 . A forced-air blower 44 , or similar device, provides a sufficiently high volume/velocity flow of pressurized air through an air supply hose or conduit 46 to move, entrain, and/or propel the aggregate along the interior of the rock transfer hose 38 to the nozzle 36 for discharge therefrom. The aggregate feeder 42 is preferably hydraulically driven and is designed to feed a measured or controlled amount of the rock aggregate into the rock aggregate transfer hose 38 to assure proper delivery of rock aggregate through the nozzle 36 to the pothole to be patched. For most applications, the rock aggregate is in the 0.25 to 0.375 inch range. The emulsion holding tank 26 contains a suitable emulsified asphalt and includes (not shown) an immersion-type heating element for maintaining the temperature of the emulsion. An air compressor 48 provides a flow of pressurized or compressed air through a compressed air line 50 to the emulsion tank 26 for pressurizing the emulsion tank 26 sufficiently to move the emulsion through a valve 52 into an insulated hose 54 to delivery to the nozzle 36 and discharge therefrom. The valve 52 is controllable to direct the flow of emulsion into the hose 54 or to cut-off the flow of emulsion and allow compressed air to flow directly into the hose 54 and to the nozzle 36 . If desired, another separately controllable air line can be provided from the compressor 48 to the nozzle 36 . [0023] The system of FIG. 4 allows for the controlled discharge of pressurized air only from the nozzle 36 , the discharge of the asphalt emulation from the tank 26 through the nozzle 36 , and the discharge of the rock aggregate from the hopper 24 , and the discharge of a mixture of the asphalt emulsion and the rock aggregate in a desired ratio from the nozzle 36 . The mixing of the rock aggregate with the asphalt emulsion takes place within the nozzle 36 with the emulsion entering into the mixing space within the nozzle 36 through holes 36 a in the interior wall of the nozzle 36 (as shown in FIG. 10 ). In addition, a solvent-type cleaning system (not shown) can be used to purge and clear those components that are in contact the asphalt emulation, diesel fuel being a preferred solvent. [0024] The boom assembly 22 is shown in side views in FIGS. 5 and 6 and in plan view in FIG. 7 and includes a mounting structure 56 , typically formed as a weldment, that is attached to the forward end the vehicle. A boom 58 is attached at one end to the mounting structure 56 by a pivot 60 that allows the boom assembly 22 to move to and from a stowed position (in which the boom 58 is carried in the cradle 28 ) under the control of the hydraulic cylinder 30 and a selected deployed position ( FIG. 1 ). Additionally, the boom 58 is connected through a second pivot 62 that allows the boom to tilt either in an upward direction or a downward direction relative to the ground surface under the control of the hydraulic cylinder 32 to control the distance between the outlet opening of the nozzle 36 and the pavement. The nozzle 36 is located at or adjacent the distal or remote end of the boom 58 with the rock aggregate transfer hose 38 ( FIG. 5 ) coupled to the nozzle 36 and with the hose 38 attached to the boom 58 by a hose tower 64 and various restraining clips 66 . [0025] In the various figures, the boom assembly 22 is shown with its pivotable end mounted on the left or driver side of the vehicle; as can be appreciated, the organization of the boom assembly can be reversed, i.e., the pivotable end can be on the right or passenger side of the vehicle, or, if desired, the pivotable end of the boom assembly 22 can be mounted at some mid-position between the left and right sides of the vehicle. In the embodiment shown, only a single boom 58 is used; however, the use of at least one other boom pivotally connected to the end of the boom 58 (with an appropriate hydraulic control cylinder) to provide a two-boom assembly is not excluded. [0026] The remote or distal end of the boom assembly 22 is shown in FIGS. 7 , 7 a , and 8 and includes the nozzle 36 pivotally mounted on an axle 68 for limited tilting or pivoting motion about an axis 80 under the control of a bidirectional electrical actuator 70 . As best shown in FIG. 7 a , the axis 80 is approximately parallel to the long axis of the boom 58 . The actuator 70 is of the type having a ball-screw driven ram 72 that extends or retracts under the control of a drive motor 74 . In the preferred embodiment, the actuator 70 is a 12 VDC linear actuator available from Warner Linear of Belvidere Ill. 61008 under the A-Track or the B-Track model designations. The remote end of the ram 72 is connected via a connecting rod 76 to a moment arm 78 and rotates the nozzle 36 about the axis 80 in response to the position of the ram 72 . The rock aggregate transfer hose 38 (not shown in FIG. 7 a ) connects to the inlet 82 of the nozzle 36 . As shown in the detail of FIG. 7 a , various hose fittings (represented at 84 ) and electrically controlled proportioning valves 86 connect to the nozzle 36 for receiving the emulsion and compressed air lines (not shown in FIG. 7 a ) and regulating the flows thereof into the nozzle 36 . The emulsion is introduced into the main nozzle passageway via interior openings 36 a as shown in FIG. 10 as discussed below. [0027] FIGS. 9 and 10 illustrate the range of angular motion of the nozzle 36 under the control of the ram 70 and a representative joystick-type controller 88 in which movement of the joystick J causes corresponding pivoting of the nozzle 36 . As shown in FIG. 9 , the nozzle 36 is pivoted counterclockwise when the ram 72 is retracted and, conversely, pivoted clockwise when the ram 72 is extended. A suitable joy-stick controller is available from SureGrip Controls, Inc., Kamloops, B.C., Canada under the JL-series designation. [0028] The pivotally or tiltable nozzle mount provides enhance functionality to the road patcher vehicle. More specifically and after the vehicle operator deploys the boom 58 to position the distal end over the pothole or area to be patched, the operator directs a flow of pressurized air (from the rock aggregate blower 44 , FIG. 4 ) to eject dust, dirt, debris, standing water, etc. from the pothole or area to be patched. Depending upon the nature of the area to be patched, the operator can pivot or tilt the nozzle 36 through some or all of its range of motion to provide a more thorough air “blast” cleaning. Thereafter, a controlled amount of the liquid asphalt emulsion is directed onto or into the area to be patched to function as a “tack” layer. The operator can pivot or tilt the nozzle 36 through some or all of its range of motion to assure complete coverage, and, if desired, also move the boom 58 under the control of the hydraulic cylinder 30 ( FIG. 7 ), to assure a seamless patch particularly along the edges of the patch. Thereafter, a mix of the rock aggregate and the liquid emulsion is blown into the patch area with the high velocity air flow functioning to ‘compact’ the mix from the bottom upward to the surface of the roadway. Lastly, a thin layer of a dry rock aggregate (i.e., without the liquid asphalt emulation) is deposited onto the patch. As in the case of the first two steps, the operator can pivot or tilt the nozzle 36 through some or all of its range of motion during the second two steps to assure proper placement of the patching materials and, if desired, also move the boom 58 as desired. [0029] In the embodiment described above, the axis 80 about which the nozzle 36 is pivoted or tilted is substantially parallel to the long axis of the boom 58 but displaced therefrom (as shown in FIG. 7 a ). Thus, in those cases were the boom 58 is fully extended so that its axis is parallel to the long axis of the vehicle, the nozzle 36 can sweep a path back and forth along the lateral or side-to-side direction. Thus, as the vehicle moves along the roadway, the nozzle 36 can be moved side-to-side as needed to provide the filling of the pothole or the repair of the damaged area. In some cases and as shown in FIG. 11 a , the nozzle 38 can be mounted so that the pivoting or tilting axis 80 is approximately perpendicular to the long axis of the boom 58 . [0030] A variation of the embodiment shown in FIG. 11 a is shown in FIG. 11 b in which two degrees of freedom are provided. As shown, the boom 58 is modified to provide a bearing mounted rotatable connection between the boom 58 and the nozzle assembly with a gearmotor 82 providing controlled rotation of the nozzle assembly about axis 84 . The gearmotor 82 include a reversible electric drive motor with a gear reduction head (or other suitable transmission) and a shaft 86 connected to the nozzle assembly to effect limited rotation about the axis 84 . As in the case of the embodiment described above, a dual-axis joystick can be used to provide control inputs. [0031] FIGS. 12 and 13 illustrate an omni-directional mount for the nozzle 36 such that two degrees of pivoting or tilting are possible. As shown in the cross-sectional view of FIG. 12 , the nozzle 36 is mounted in a spheroid mount that includes a rotor member 90 having a surface of revolution 92 that is a partial sphere. The rotor member 90 is carried in a stator 94 having a mating surface with sufficient clearance that the rotor member 90 and the nozzle 36 an pivot or tilt from the vertical. As shown in FIG. 13 , a connecting plate 96 is mounted to the nozzle 36 at its upper end and includes and appropriate number of connecting rod ends 98 that connects to an appropriate pull and/or push actuator, such as the linear electric actuator 70 described above or a fluidic (hydraulic or pneumatic) actuator (not shown). Conventional joystick controllers 100 are used to individually control the two actuators shown; in the alternative, a single joystick type controller with a 360° range that provides appropriately resolved signals to the actuators can be used. The rod ends 98 are of the type (i.e., ball ends) that allow of angular movement so that to accommodate the tilting of the nozzle 36 . [0032] As will be apparent to those skilled in the art, various changes and modifications may be made to the illustrated embodiment of the present invention without departing from the spirit and scope of the invention as determined in the appended claims and their legal equivalent.	A road patching vehicle for patching damaged areas or potholes of various sizes and shapes on a roadway includes a boom assembly pivotally mounted at or on the forward end of the vehicle with a nozzle mounted at or toward the forward end of the boom. Various hoses connect the nozzle to a source of pressurized air, a source of patching emulsion (such as an asphalt emulsion), and a source of a rock aggregate with the vehicle operator controlling the flows individually or in various combinations thereof to prepare and then fill the pothole or other road defect to effect a patch. The nozzle is mounted on a pivot or journal to allow controlled pivoting or tilting of the nozzle under control of the operator in at least one degree of freedom. In a variant of the preferred form, the nozzle is mounted for control pivoting or tilting under the control of the operator in at least two degrees of freedom.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of the filing date of U.S. Provisional Application Serial No. 60/622,418, filed Oct. 27, 2004, which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] Suspended ceilings of various shapes and sizes are being increasingly used in order to add interest to various public spaces, such as retail outlets, contemporary office lobbies and halls, entertainment establishments, and the like. This has lead to the creation of suspended ceiling systems for defining spaces in which the ceiling panels lie in more than one plane, such as in vaults, transitions between different ceiling heights, islands, and waves. [0003] One problem with such non-conventional ceiling systems is the difficulty of installing the suspending grid so that the runners for supporting the associated ceiling panels are maintained in accurate alignment. In particular, this difficulty has lead to increased time and cost for the assembly of such suspended ceiling systems. [0004] Accordingly, by way of the invention described herein, a suspended ceiling system is provided that is particularly suited for providing a grid system that is curved in vertical plane, provides for accurate spacing and alignment of the grid elements, and facilitates quick assembly and installation of the assembled grid system. BRIEF DESCRIPTION OF THE DRAWINGS [0005] FIG. 1 is a perspective view of a grid system for a curved suspended ceiling in accordance with the present invention. [0006] FIG. 2 is a perspective view of a portion of a primary carrier in accordance with the present invention. [0007] FIG. 3 is a perspective view of a splice for connecting primary carriers in accordance with the present invention. [0008] FIG. 4 is a perspective view showing the splice of FIG. 3 joining two primary carriers in accordance with present invention. [0009] FIG. 5 is a perspective view of a portion of the grid system according to the present invention showing a clip for securing a primary carrier to a main runner. [0010] FIG. 6 is an enlarged perspective view of the clip for securing the primary carrier to the main runner. [0011] FIG. 7 is a perspective view of a portion of the grid assembly showing a connection of a primary carrier to a perimeter trim piece. [0012] FIG. 8 is an enlarged perspective view of a clip for securing the primary carrier to the perimeter trim piece. [0013] FIG. 9 is a perspective view of a portion of the grid system of the present invention showing the connection of a main runner to a trim piece. [0014] FIG. 10 is an enlarged perspective view of a clip for securing a main runner to a trim piece. [0015] FIG. 11 is a perspective view of a portion of the grid system showing two pieces of trim connected to each other by means of a splice clip. [0016] FIG. 12 is an enlarged exploded perspective view of the splice clip for connecting two trim pieces together. [0017] FIG. 13 is a perspective view of a hanger clip for securing the hanger wire to the primary carrier. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0018] The present invention comprises an assembly particularly suited for a curved suspended ceiling grid. With reference to FIG. 1 , the system, generally designated 10 , includes main runners or tees 12 which are curved in a vertical plane to support either flexible panels 13 or preformed, lay-in panels (not shown), the latter requiring cross-tees between adjacent main tees. The curve may be either concave or convex with respect to the exposed side of the ceiling system. Edge or perimeter trim pieces 14 (which may be either curved or straight, as required to correspond to the shape of the main runners 12 ), having opposed interior slots define the perimeter of the suspended ceiling. Corner clips are used to secure the perimeter trim pieces to each other. However, the perimeter trim may be omitted, if desired, without departing from the invention. Each of the main runners, trim pieces and corner clips have previously been available from Chicago Metallic Corporation, assignee of the present application, under the “CurvGrid” and “CurvTrim” trademarks. [0019] In keeping with one aspect of the present invention, one or more primary or tube carriers, generally designated 20 , is utilized to interconnect the main runners 10 and provide a unitized, rigid grid system. Each primary carrier 20 preferably extends substantially the full width of the suspended ceiling and is preferably spaced no more than about 48 inches from the adjacent primary carrier. The primary carrier 20 may be of any length that is practical given both manufacturing and shipping constraints, and typically may be as long as 16 feet in length. [0020] The primary carrier 20 preferably has a circular cross-section, with an outside diameter of approximately 1.25 inches, although other cross-sectional shapes and sizes may be utilized without departing from the invention. The primary carrier has a notch or slot 22 for each of the main runners supported by the tube carrier 20 , the notch 22 being sized in width and depth to receive the bulb of the main runner. In a preferred embodiment, the tube carrier 20 is roll-formed from 0.028 inch thick steel with a lock seam 20 a. The notches 22 aid in the installation of the ceiling by maintaining on-center spacing of the main runners 10 without the use of cross tees. [0021] If the width of the curved ceiling is greater than the length of a single primary carrier 20 , adjacent primary carriers can be staggered so that together they extend substantially the full width of the ceiling. More preferably, one or more primary carriers may be joined together end-to-end to obtain the desired length by using a splice connector 21 , as shown in FIG. 3 . With reference to FIGS. 3 and 4 , approximately half the length of the splice connector 21 is received in the interior of each of the two primary carriers joined thereby. The primary carriers and splice connector may be positively secured to one another by fasteners, such as screws 21 a. The primary carriers 20 may also include an inwardly-projecting embossment spaced from their ends that serve as a stop to prevent over insertion of the splice clip 21 into the primary carriers 20 . [0022] The splice connector 21 may be made from electrical metallic tube (commonly referred to as “EMT”) having an outside diameter and cross-sectional shape that is complementary to the inside diameter and cross-sectional shape of the primary carrier 20 . The splice connector 21 has a slot 21 b along its length to allow it to mate with a lock seam 20 a in the tube carrier 20 , thus preventing rotation of the splice clip 21 and maintaining the angular alignment of the splice clip relative to the primary carriers 20 . [0023] With reference to FIGS. 5 and 6 , clips 24 with cut-outs 26 are provided that fit over the top of the primary carrier 20 to secure the main runners 10 to the primary carrier 20 . The cut-outs 26 are generally complementary in shape to the primary carrier and thus, in the illustrated embodiment, are generally an inverted U-shape. The clip 24 is provided with opposed faces 28 , the bottom edges 30 of which terminate in inwardly-pointing lips that are adapted to support the bottom surface of the bulb of the main runner. Alternatively, the clip 24 may be formed with inwardly-pointing tabs (not shown) for the same purpose. The clip 24 has aligned holes 34 in its opposed faces 28 for receiving screws 36 that draw together the lips or tabs on the clips so that they securely support the bulb of the main runner 10 . The clip 24 preferably includes stand offs 37 that are received on the shanks of the screws 36 and are sized in length to prevent over-tightening for the screws. [0024] One advantage accruing to the present invention is that the primary carrier provides a cantilevered attachment point for the perimeter trim, allowing the hanger wire for suspending the grid to stand off from the end of the carrier tube, thus shielding the hanger wire from view. To this end, a perimeter clip 38 for securing the primary carrier 20 to a trim piece 14 is shown, best seen in FIGS. 7 and 8 . The primary carrier perimeter clip 38 comprises three L-shaped segments 40 , 42 , 44 , joined together on one leg of the L, that are bendable into a generally U-shaped member. When bent, the corner 46 of one leg of each of the outer L-shaped segments is partially received in the upper of two opposed slots on the trim pieces, while the edge 48 of the corresponding leg of the middle L-shaped segment is received in the lower of the two opposed slots. The other leg of each L-shaped segment extends generally perpendicularly from the trim piece 14 to support the primary carrier 20 . Each of the two outer arms that support the primary carrier 20 includes an aperture 50 adapted to receive a screw or other fastener for positively securing the clip 38 to the primary carrier 20 . [0025] With reference to FIGS. 9 and 10 , a second perimeter clip 52 is shown for securing the main runners 10 to a perimeter trim piece. (Such clips may also be used to secure cross tees, if used, to a perimeter trim piece.) The main runner perimeter clip 52 is also generally L-shaped, with one leg of the L having opposed edges that are received in the opposed slots of the straight trim piece 14 . This leg preferably includes a tapped hole 54 for receiving a set screw 56 that may be tightened against the web of the trim piece 14 to lock the perimeter clip 52 thereto. Preferably, this leg has a curved edge 58 that permits the clip 52 to be positioned on the trim piece and then simply twisted to cause its edges to locate in the opposed slots in the trim piece. The other leg is adapted to lie along the web of the main runner 10 , and includes an ear 60 which can be folded through a slot in the main runner 12 to lock the main runner thereto. [0026] Turning to FIGS. 11 and 12 , a splice clip 62 is provided for joining lengths of perimeter trim 14 to each other. The splice clip 62 has two parts 64 , 66 . The first part 64 has opposed edges 68 which are received in the opposed slots on the trim piece. The second piece 66 overlies the first piece 64 to clamp the lips that define the slots in the trim piece between the two pieces of the splice clip 62 . The second piece 66 has four corners 70 that are bent downwardly to engage the lips of the channels that receive the first piece 64 . The two pieces 64 , 66 of the splice clip 62 are attached together by a pair of screws 72 . [0027] The grid system of the present invention is suspended by hanger wires secured to the primary carriers, rather than to the main runners. This minimizes the number of hanger wires required to support the system. For smaller-sized ceilings, the curved grid system as described can be easily and accurately assembled on the floor of the space in which it is to be installed, and then raised as a unit in order to secure the hanger wires to the tube carriers. Otherwise, the primary carriers 20 are first hung, and the remaining components of the grid system then secured thereto. With reference to FIGS. 1, 4 and 13 , a plurality of hanger clips 74 is provided that secure the hanger wire to the primary carriers 20 . The hanger clips 74 have a strap portion 76 that is partially covered with a resilient, rubber-like sleeve 78 that conforms to the shape of the surface of the tube carrier 20 contacted by it. The hanger clips 74 have a slightly oversized opening with respect to the diameter of the primary carrier in order to permit a minor amount of relative rotation between the hanger clip and the primary carrier. This ability to rotate with respect to each other allows a certain amount of “self centering” of the tube carrier with respect to the hanger wire, so that the hanger wire extends generally perpendicularly from the primary carrier. This subjects the hanger wire to less stress at the point at which it is secured to the hanger clip. [0028] Thus, a suspended ceiling system particularly suited for a curved grid has been provided that facilitates accurate and quick assembly with enhanced structural rigidity. While the invention has been described in terms of a preferred embodiment, it is not intended to be limited to the same. Indeed, variations are contemplated that are within the ordinary skill in the art. For example, while the system has been described in connection with curved main runners, the primary carriers could also be used with a more conventional planar grid system. In addition, while cross tees are not required for structural reasons, they may still be utilized with the present invention for aesthetic reasons if, e.g., the lay-in panels have an edge reveal. Also, the primary carrier may have a cross-section other than generally circular without departing from the invention.	A grid system is provided that is particularly suited for the suspended ceiling system that varies in the vertical plane. An elongated carrier tube is provided the spans substantially the width of the grid system that has a slot therein adapted to receive the strengthening bulb of a main runner. A clip is provided that seats on the carrier tube that has opposed faces for capturing the bulb of the runner, so as to secure the runner to the tube carrier.
You are an expert at summarizing long articles. Proceed to summarize the following text: RELATED APPLICATIONS [0001] This application is related to U.S. patent application Ser. No. 10/446,006, filed May 22, 2003 and U.S. patent application Ser. No. 10/871,557, filed Jun. 18, 2004. FIELD OF THE INVENTION [0002] This invention relates to the protection of property against high winds and, in particular, to a flexible protective barrier device for securing property against the force of winds, rain and from impact of foreign objects carried by localized atmospheric over-pressure. BACKGROUND OF THE INVENTION [0003] As is known by one skilled in the art of protecting buildings and the like from damage caused by missile-like objects that are occasioned by the heavy winds of hurricanes, tornadoes, or explosive over-pressures, there are commercially available variations of hurricane protective devices, often called shutters, that fasten immediately over the frangible area to be protected. These devices are typically expensive to purchase cumbersome, made from stiff, heavy material such as steel and aircraft quality aluminum alloy or occasionally reinforced plastic. Many need to be manually connected and then removed and stored at each threat of inclement weather. Many require unsightly and difficult-to-mount reinforcing bars at multiple locations. Further, these known shutters are usually opaque, preventing light from entering a shuttered area and preventing an inhabitant from seeing out. Likewise, it is desirable that police be able to see into buildings to check for inhabitants and to prevent looting which can be a problem in such circumstances. [0004] Missiles, even small not potentially damaging missiles, striking these heretofore known shutters create a loud, often frightening bang that is disturbing to inhabitants being protected. Standardized testing requiring these protective devices to meet certain standards of strength and integrity has been introduced for various utilizations and locales. In order to qualify for use where testing requirements apply, the strength and integrity characteristics of these protective devices must be predictable and must be sufficient to meet mandated standards. [0005] Additionally, it is beneficial to qualify for these standards even in situations in which standards do not apply. As a result of these standards, many undesirable aspects of the previously known shutters have been acerbated. They have become more cumbersome, more bulky, heavier, more expensive, more difficult to store, and remain generally opaque and noisy when impacted. [0006] To incorporate sufficient strength to meet said requirements, weight and bulk become a problem over six feet in span. The useable span (usually height) of the heretofore known shutters that meet said standards may be limited to eight feet or less. This makes protecting large windows, for example, or groupings of windows, with the heretofore known devices cumbersome, expensive and impractical. Devices that are intended to be deployed in a roll down manner either manually, automatically, or simply by motor drive, have been difficult to strengthen sufficiently to pass the test requirements and require unsightly reinforcing bars every few feet. [0007] Prior to the introduction of said standards, an ordinary consumer had very little useful knowledge of the strength and integrity of said shutters. It is believed shutters of the pre-standard era were very weak such that all would fail the present standardized testing. As the hurricane conditions can be very violent and destructive, the standards are not intended to require strength and integrity sufficient to protect in all circumstances. The standards simply provide a benchmark as to strength and integrity. The strength and integrity of the shutters can now be measured by standardized tests. [0008] There are many patents that teach the utilization of knitted or woven fabric such as netting, tarpaulins, drop cloths, blankets, sheets wrapping and the like for anchoring down recreational vehicles, nurseries, loose soil and the like. But none of these are intended for, nor are capable of withstanding the forces of the missile-like objects that are carried by the wind in hurricanes or explosive over-pressures. [0009] Some protection devices have internal stiffness and rigidity that resists deflection, or bending. In rigid protection devices, it is stiffness that stops the missile short of the frangible surface being protected. [0010] Other protection devices use fabric or netting material to cover a unit to be protected. Typically, the device completely covers the unit, and edges of the fabric are fastened to the ground. Examples of fabric employing devices are shown in the following patents: U.S. Pat. No. 3,862,876 issued to Graves, U.S. Pat. No. 4,283,888 and U.S. Pat. No. 4,397,122 issued to Cros, U.S. Pat. No. 4,858,395 issued to McQuirk, U.S. Pat. No. 3,949,527 issued to Double et al., U.S. Pat. No. 3,805,816 issued to Nolte, U.S. Pat. No. 5,522,184 issued to Oviedo-Reyes, U.S. Pat. No. 4,590,714 issued to Walker and U.S. Pat. No. 5,522,184 issued to Pineda. U.S. Pat. No. 5,522,184, for example, provides a netting that fits flush over the roof of a building and uses a complicated anchoring system to tie down the netting. [0011] Typical of known flexible, fabric-employing protection devices is the characteristic of substantial rain and wind-permeability. For example, U.S. Pat. No. 5,579,794, issued to Sporta, discloses a wind-permeable perforate sheet that extends downwardly and outwardly from the top of the object to be protected at an acute angle so as to surround a substantial portion of each of the sides with an inclined wind-permeable planar surface. [0012] U.S. Pat. No. 6,325,085 to Gower illustrates a barrier similar to the instant invention to be deployed inside a building or over individual windows. U.S. Pat. No. 6,176,050 to Gower teaches the use of the barrier material of this invention deployed over multi-story buildings. Both patents are incorporated herein by reference. [0013] Thus, what is lacking in the art is an improved flexible protective barrier constructed from a mesh material with substantial rain and impact resistance that can be easily stored and deployed in combination with a flexible, inflatable, reinforcing cushion for protecting the frangible portion of a structure not only from objects carried by the wind but also from the force of the wind itself. SUMMARY OF THE INVENTION [0014] Therefore, it is an objective of this invention to teach the use of a flexible barrier synthetic textile that is able to satisfy stringent testing requirements. When used with a building, for example, the top edge of the fabric may be anchored to the eave of the roof and the bottom of the fabric may be attached to anchors imbedded in the foundation, ground or cement, so as to present a curtain adequately displaced from and in front of the structure of the building to be protected. [0015] Knitted, woven or extruded material can be used if the material itself meets the criteria described later herein. The device provides a barrier that is substantially impermeable to rain and wind. Although air travels through the barrier, the barrier is approximately 95% closed, and the velocity of wind passing through the device is greatly reduced. For example, the velocity of a 100 mph wind is reduced by approximately 97% by passing through the wind abatement system of the present invention. The wind abatement system of the present invention substantially reduces the force of wind passing through the device and also provides a barrier against wind-borne missiles having diameters of approximately 3/16 inch in diameter or larger. Also, rain drops striking the barrier are reduced in velocity and dispersed into a mist which reduces the water damage to the structure. [0016] Alternatively the material can be termed to be solid wherein the fabric is coated or the interstices of the fabric are filled by either close weaving, or use of a coating. [0017] The inflatable cushion(s) between the fabric and the building provide displacement and pneumatic dissipation of the force of impact of debris on the fabric. This pneumatic plenum allows the flexible barrier system to be in direct contact with the structure being protected. [0018] Another objective of this invention is to teach the use of very large areas with spans covering greater than 25 feet. Thus most window groupings, from a single window up to several stories of a building, could be readily protected. This invention is light in weight, easy to use, does not require reinforcing bars, can be constructed in varying degrees of transparency, can be weather tight, is economical, and is capable is dissipating far greater forces without damage than conventional stiff devices. Missiles striking this barrier make very little sound. Additionally, this invention is suitable to be configured with the necessary motor and mounting devices for automatic deployment. [0019] Another objective of the invention is to permit the adaptation of the invention to meet a particular enclosure or object. For instance, the inflatable cushion(s) may be placed over a window, preferably a wind rated window, to provide the necessary spacing. Alternatively the inflatable cushion(s) may be placed over the mullions of a window thereby transferring wind loading directly to the inflatable cushion and thus to the structure of the mullion. Further, the inflatable cushion(s) may be placed along the edge of the window or on the structure abutting window. Similarly, the inflatable cushion(s) may be placed adjacent an object, such as a tiled wall, painting, statue, sculpture, or the like, to prevent wind, rain, and debris from impacting the object. [0020] It is a further objective of this invention to teach a wind barrier that does not rely on rigidity but rather is very flexible, which gives several positive features including allowing for ease of storage as by deflating and rolling or folding. The fabric material in this barrier system is displaced from the structure being protected and this displacement is a function of the depth of the inflatable cushion. An impacting missile stretches the barrier until it decelerates to a stop or is deflected. The fabric material has a predetermined tensile strength and stretch that makes it suitable for this application. The known strength and stretch, together with the speed, weight and size of the impacting missile, all of which are given in test requirements, permit design calculation to ascertain barrier deflection at impact. The cushion is capable of a deflection, due to compression, commensurate with the stretch of the fabric to prevent rupture. [0021] Thus greater energy from a missile can be safely dissipated than is possible with the prior art structures, and the energy which can be safely dissipated is calculable. In simple terms, the missile is slowed to a stop by elasticity as the barrier stretches and compression as the cushion deforms. The greater the impact, the greater the stretch and compression. Thus the building is not subjected to an abrupt harsh blow as the energy transfer is much gentler and less destructive that with the rigid devices. [0022] It is yet another objective of this invention to teach the use of a screen-like fabric with interstices that permit the light to pass through and that is reasonably transparent, if desired. If transparency is not desirable, the fabric can be made sufficiently dense to minimize or eliminate the interstices. To assure a long life the material of the fabric preferably would be resistant to the ultra violet radiation, and to biological and chemical degradation such as are ordinarily found outdoors. This invention contemplates either coating the material or utilizing material with inherent resistance to withstand these elements. A synthetic material such as polypropylene has been found to be acceptable. Another example is a coated material of vinyl coated polyester. The coating may fill interstices to make a solid material. The fabrics may use natural or synthetic fibers and blends of fibers or blends of yarns, e.g., an open weave with steel reinforcing strands there through or Kevlar or other ballistic yarns. Materials intended to be used outdoors in trampolines, for example, are more likely candidates for use in this invention. Black colored polypropylene is most resistant to degradation from ultra violet radiation. Other colors and vinyl coated polyester are sufficiently resistant, particularity if the barrier is not intended to be stored in direct sunlight when not in use. [0023] These same materials may be used to form the walls of the inflatable plenums or cushions. The cushions may be coated or laminated on the outside or inside surfaces to form air tight cells. The cushions may be made of extruded polymeric films. The desired amount of deformation, in the cushion, is a function of the elasticity of the material and the inflation pressure. The plenums may also be thin walled structures inserted into a sleeve of the barrier material which provides the requisite strength. [0024] The preferred embodiment of the fabric allows air passage through it, albeit at substantially reduced rate. In one embodiment, upwind pressure of 1″ of mercury, which roughly translates into a 100 mph wind, forces air through at 250 cfm or approximately 3 mph. The amount of air passage depends on the interstice size and percentage of openness. If a weather tight and transparent barrier is desired, the polypropylene material may be laminated with a flexible clear plastic skin. [0025] It is of importance that the material affords sufficient impact protection to meet the regulatory agencies' requirements in order for this to be a viable alternative to other hurricane protective mechanisms. While stiff structures, such as panels of metal, are easily tested for impact requirement and have certain defined standards, fabrics on the other hand, are flexible and react differently from stiff structures. Hence the testing thereof is not easily quantified as the stiffer materials. [0026] However, certain imperial relationships exist so that correlation can be made to compare the two mediums. Typically, the current impact test of certain locales requires a wood 2×4 stud be shot at the barrier exerting a total force of approximately 351 foot pounds, or 61.3 psi, over its frontal (impacting) surface. This impact and resultant force relate to the Mullen Burst test commonly used by manufacturers to measure the bursting strength of their fabrics. Thus the impact test heretofore used on rigid devices will work equally well on this flexible device. [0027] The preferred embodiment of this invention would use a textile of the type typically used in trampolines which would burst at least 675 psi or a total of 2,531.25 pounds over the same 3.75 square inch frontal surface of the nominal 2×4 test missile wherein stretch characteristics of the material are known. The strength and stretch characteristics of the material are also known. The strength of this fabric is more than eleven (11) times the 351 foot pounds of strength required to withstand the above-described 2×4 missile test as presently required by said regulatory agencies. Stronger fabrics are available. Others are available in various strengths, colors and patterns. [0028] The use of flexible fabric distanced out from the frangible area as a protective barrier allows extended deceleration. When the strength and stretch properties of the fabric are known and allowed for, as well as, these same properties in the inflated cushion, the extended deceleration becomes controlled. By mounting the protective barrier material some distance from the frangible surface, i.e., the thickness of the inflated cushion, a distance that is calculable, the missile can be decelerated to a stop prior to contacting the frangible surface. And the pounds per square inch of impact force are spread throughout the inner surface of the cushion. In other words, in any situation where the missile must stop prior to impacting the frangible surface being protected, it is desirable to decelerate the missile through an extended, controlled deceleration. This invention does precisely that. Since the use of a flexible material as a protective barrier affords an extended deceleration, very strong impacts can be withstood. [0029] A further objective of this invention is to teach a barrier made from fabric to protect the frangible portions of a building and the like from the force of wind, or over pressure, and impact from water or other liquids and wind-borne debris by displacing the barrier out from and in front of the frangible area with inflatable cushions. The barrier is mounted on the building by attaching two opposing edges to anchors located so as to position the barrier as described. For example, one edge of the fabric can be anchored to the overhang of the roof or other high structure and the opposite edge of the span to the ground or low structure. The lower anchors can be attached to the foundation of the building or the ground by embedding in cement or other ground attachment such as tie downs or stakes and the like and providing grommets, rings or other attachments in the fabric to accept a clamp, cable, rope, and the like. [0030] Another objective of this invention is to teach an inflatable structure placed between any opening in a structure and may be spaced from the structure a greater distance than the thickness of the cushion to allow for some deceleration before the cushion is compressed. [0031] Still another objective of this invention is to teach the use of a retainer for deploying and securing the two opposing edges of a wind barrier material to retainer channels located so as to form a structure envelope about the openings with the barrier spanning the opening. [0032] The curtain-like barrier of this invention is characterized as a barrier with strength and simplicity that is unattainable with the heretofore known barriers. Impact by a missile does not cause a large bang, and is not disturbing. It is easy to install, requires low maintenance and has low acquisition cost. There is much flexibility with storage. It can either be left in place or rolled much as a shade, or slid out of the way much as a curtain, so as not to interfere with the aesthetics of the building. It can also be fully removed and stored out of the way, or swung up to form a canopy when not in use as a protective barrier. It is preferable but not essential, that the material selected to be used in the netting fabric of this invention be inherently resistant to elements encountered in the outdoors or can be coated with coatings that afford resistance to these elements. The inflatable cushions can be separate from the netting or attached by interweaving, fasteners or pockets in the netting. The cushions may be stored with the netting or removed for storage elsewhere. [0033] Another objective of this invention is to teach the use of valves in the inflatable cushions whereby they can be deflated for storage and inflated once the barrier is in place on the building. [0034] Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by the way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. BRIEF DESCRIPTION OF THE DRAWINGS [0035] FIG. 1 is a partial view in perspective and schematic illustrating this invention partially deployed and attached to a building; [0036] FIG. 2 is a partial cross section and side view illustrating the protective barrier and inflated cushion in place; [0037] FIG. 3 is a perspective of the barrier showing holders for the cushions; [0038] FIG. 4 is a detailed showing of a mechanism for attaching the retainers to the barrier; [0039] FIG. 5 is a detailed view of another mechanism for attaching the retainers to the barrier; [0040] FIG. 6 is a diagrammatic and schematic view illustrating the channel; [0041] FIG. 7 is a perspective of a protective barrier for individual openings or small groups of openings; and [0042] FIG. 8 is a perspective of a single window with an inflatable barrier in place. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0043] This barrier 10 is made up of a flexible material 11 that has known qualities of strength, stretch and deformation and is sufficiently strong to withstand applicable impact testing and one or more inflatable plenums or cushions 12 . The barrier 10 does not derive its strength from stiffness or rigidity but rather from its bursting strength and stretch, with the latter acting like a spring to gradually decelerate any impacting missile. Wind speed may become a significant factor in larger spans. [0044] There are many desirable characteristics of this barrier 10 , such a resistance to weathering, light weight, ease of installation, deployment and storage, economy. Additionally, there are several methods of deploying and storing this barrier. While this invention is shown in its preferred embodiment as being utilized to protect the windows and overhang roof, shown in FIG. 2 , of a structure, it is to be understood that this item has utility for other items requiring protection and is applicable to other types of structures, as shown in FIG. 8 . Where appropriate, the barrier and inflatable plenums can be deployed horizontally, as well as, the vertical as shown in FIGS. 1-2 . [0045] Reference is now made to FIGS. 1-6 which partially show a building structure 100 including windows 110 intended to be protected from the onslaught of winds and debris typically occasioned during a hurricane. According to this invention the top of a curtain panel or material 11 , made from a textile woven of a suitable fiber, (other weaves or knits may be used) is attached to roof 16 and the bottom thereof is attached to the foundation 200 . A suitable material is polypropylene formed in a monofilament and woven into geotextile (style 20458) manufactured by Synthetic Industries of Gainesville, Ga. The fabric is woven in a basket (plain) weave as in the preferred embodiment in interstices are substantially equal to 0.6 millimeters which approximates the interstices of commercially available residential window screening. [0046] The selection of interstices size and configuration is dependent on the amount of transparency and air passage desired and the limitation that the maximum size must be sufficiently small to prevent objects that are potentially damaging on impact from passing there through. The above-mentioned regulations, set in place by Miami-Dade County, Florida, have determined that the smallest diameter missile (wind blown debris) with which they are concerned is 3/16 inch in diameter. Therefore to satisfy the Dade County Regulations the interstices must be small enough to prevent 3/16 inch diameter missiles from passing there through. Other regulations may set other minimum missile diameter sizes, and the interstice size would vary accordingly if new standards were to be met. The parameters of the test and the fabric are fully discussed in U.S. Pat. No. 6,176,050. [0047] The cushions 12 have conventional inflation-deflation valves 116 , such as those used in tires or sports equipment. The valves may include a safety valve which will open when a pre-selected internal pressure is exceeded. This will prevent rupture of the cushion. The inflation pressure of the cushions 12 can be adjusted to compensate for the impact pressure of the debris or test missile. A higher inflation pressure would decrease the amount of deflection of the material. In this manner, the improved barrier 10 would not require the spacing necessary with the material, per se. For example, a cushion having a depth of 2 feet may be used in spans from 8 feet to 40 feet and beyond. This permits attachment of the bottom of the barrier to the protected structure, as shown in FIG. 8 , rather than being displaced away from the building. [0048] The top of the barrier 10 is secured to the roof 101 , facia 102 , or under the eave 103 . The bottom of the barrier would be secured to the foundation 200 of the building by fasteners 119 . The longitudinal sides 13 , 14 of the barrier are mounted in retainers 104 , 105 . The retainers 104 , 105 , as shown in FIG. 6 , are elongated box-shaped metal sections permanently attached to the building. The retainers may be installed in sections or as a seamless whole. The top of the retainers 104 , 105 have a flared opening 106 , 107 to facilitate the feeding of the barrier 10 into the retainers as the barrier 10 is unrolled into position. [0049] The base 108 of the retainers is bolted or otherwise fixed to the structure 100 . The top wall 114 is parallel to the base. The outer wall 109 has a height that provides the spacing of the material 11 from the building 100 to permit the inflatable cushions to be deployed. The outer wall 109 of the opposite retainers 104 , 105 enclose the longitudinal edges of the barrier to prevent wind entry between the barrier and the building. The inner wall 110 has a longitudinal groove 111 through which the longitudinal selvage edge of the material 11 slides. The groove 111 terminates in an enlarged channel 112 of a size and shape to permit the pins 113 to move. [0050] The pins 113 , shown in FIGS. 4 and 5 , are tapered from the central position toward each end. The pins may be attached to the longitudinal selvage by tabs 120 or hemmed into the selvage. As the barrier is deployed each pin enters the flared end of the retainers and slides down the channel. Since the slot is narrower than the diameter of the pins, the pins are captured in the channels. Other arrangements can include a cable attached to the longitudinal edges of the material. [0051] Once the minimum space between the barrier and the structure being protected is established, the fabric must be anchored in a suitable manner so as to absorb the loads without being torn from its support. While various hardware devices may be used to anchor the fabric in place, general criteria include stainless steel bolts with 0.5 inch diameter and 1,000 lbs. max. bolt loading; 0.375 inch diameter and 625 lbs. max. bolt loading; with minimum pull-out force for steel 20× bolt loading; concrete 3,000 psi, spaced to achieve 1,100 lbs./linear foot; wood 2,400 lbs/linear inch of engaged thread; ground 8 inch helix ground anchor with 9,900 lbs. holding force in class 5 soil. These criteria are merely exemplary and not limiting. Other anchoring hardware may be used to install protective barrier of this invention. [0052] As shown in FIGS. 1 and 2 the protective barrier 10 may be unrolled from a spindle 15 that is attached to the roof 101 or the eaves 103 of the roof by suitable threaded bolts or screws. The spindle attaching method allows for ease of installation as the installer can wrap the material around the spindle as necessary to adjust the material to the span and then attach the spindle to the building. Additionally, the use of a spindle 15 allows the edge if the barrier to be securely fastened overhead in a simple and economical method. Other methods are available in appropriate situations. The lower edge is fastened by anchors 118 set in recesses formed into the foundation to bury or partially bury eyebolts. [0053] The material 11 may also be fabricated with a top and bottom selvage or hem or can utilize a reinforcing tape such as “Polytape” that is made from a polypropylene material. The selvage or tape may include commercially available grommets or rings to accept the tie-down hardware. The side margins may also have a selvage or other reinforcement with either grommets or ties for fastening to anchors placed in the wall of the structure. [0054] The material, as shown in FIG. 3 , may have one or more belts 117 for containing the cushions in alignment with the material 11 . The belts may be of the same material or an elastic fabric. The belts 117 may be formed as loops with intermediate portions attached to the barrier by interweaving, adhesives or other fasteners. The loops would accommodate the width of the cushions. Alternatively or in addition, pockets may be fashioned in the top and bottom to enclose the ends of the cushions. The cushions or plenums may be completely surrounded by the fabric, as shown in FIG. 7 . [0055] The multiple story installation may be deployed simply by attaching the upper edge of the barrier to the bolts on the building and feeding the barrier into the top of the retainers then allowing the barrier to fall toward the ground. Once the lower edge becomes free, it can then be attached to a set of lower fasteners located at the corresponding vertical height on the building or the ground. The barrier can be winced down by a hand crank or motorized winch (not shown) attached by a line to the bottom selvage of the barrier. Thin metal, polymeric or wooden battens 115 may be placed across the width of the barrier at spaced intervals to control deployment evenly. Once the barrier is in place, the cushions 12 are inflated to the desired pressure. To store the barrier, the cushions are deflated and either removed or rolled up with the material 11 . [0056] The inflatable wind barrier may be deployed for individual openings such as windows and doors rather than covering major surfaces of a building, as shown in FIG. 8 . FIG. 7 illustrates a plenum 12 encompassed by the material 11 . The material 11 has flaps 131 , 132 extending outwardly from the sleeve 130 . Each flap terminates in a selvage 135 , as shown. Grommets 133 are attached through the selvage 135 providing apertures 134 to connect to anchors along the periphery of the opening. Top and bottom flaps may also be provided. Other attachment devices, such as hooks, may be used in place of the grommets. [0057] The cushions or plenums 12 may be inflated by pumps supplying high volume low pressure inflation, HVLP, for example home vacuum cleaners through a valve. The valve may include a means for sealing of the opening similar to a tire valve, inflatable dinghy valve, or conventional air cushion valve. [0058] FIG. 8 illustrates a single frangible opening, such as a window 201 , in a larger structure. The structure has a set of fasteners 202 mounted about the periphery of the window. Connected to these fasteners are the edges of the barrier material 11 . The edges may have selvages and grommets 203 as mentioned above. Plenums 204 are located between the barrier and the window and are held in place by the fabric of the barrier. The plenums provide the spacing necessary for the fabric to decelerate debris, such as solids and liquids, before striking the frangible portion of the window. However, even if the frangible portion is broken, the barrier remains intact providing protection to the interior of the structure. [0059] The inflatable cushion(s) permit adaptation of the barrier to meet the design of a particular enclosure or object. For instance, the inflatable cushion(s) may be placed directly over a window, preferably a wind rated window, to provide the necessary spacing of the fabric from the glass. Alternatively the inflatable cushion(s) may be placed over the mullions of a window thereby transferring wind loading directly to the inflatable cushion and thus to the structure of the mullion. Further, the inflatable cushion(s) may be placed along the edge of the window which is stronger than the center, or on the structure abutting window such as the frame or actual structure abutting the window. Similarly, the inflatable cushion(s) may be placed adjacent an object, such as a tiled wall, painting, statue, sculpture, or the like, to prevent wind, rain, and debris from impacting the object. [0060] Although this invention has been shown and described with respect to detailed embodiments thereof, it will be appreciated and understood by those skilled in the art that various changes in form and detail thereof may be made without departing from the spirit and scope of the claimed invention.	A flexible hurricane shutter or barrier to protect buildings from over pressure has inflatable cushions held in place by a fabric material capable of withstanding winds in excess of 100 mph. The barrier can be stored on site in a rolled fashion. Retainers are mounted on a building to guide and secure the longitudinal edges of the fabric to permit ease of deployment. The retainers may be spaced apart over one side of a building and the barrier may be deployed over an entire surface of a multi-story building by raising and lowering the fabric. Inflatable cushions are held between the fabric and the building. The inflated cushions reinforce the material and distribute the force of impact throughout the surface of the cushions and act as spacers to both hold the fabric off the structure and focus the forces onto stranger portions of the structure.
You are an expert at summarizing long articles. Proceed to summarize the following text: The subject patent application claims priority to and all the benefits of Chinese Patent Application No. 2007-10023276.1, which was filed on 14 Jun. 2007 with the State Intellectual Property Office of the People's Republic of China. FIELD OF THE INVENTION The present invention relates to a portable blower-vacuum device. BACKGROUND A portable blower-vacuum device can be converted between a blowing mode or vacuum mode. Convertible blower-vacuum devices are widely used by homeowners and grounds keepers to keep outdoor areas clear of leaves, grass clippings and debris. A conventional blower-vacuum device disclosed in U.S. Pat. No. 6,141,823 comprises a vacuum nozzle and a blower nozzle extending in parallel to each other and connected to a main body housing a fan and a motor. The main body is provided with a dust bag. In the vacuum mode, air is directly sucked from the vacuum nozzle and introduced into the dust bag by the rotation of the fan. In the blower mode, the air is similarly sucked from the vacuum nozzle and is directed towards the blower nozzle. The blower nozzle is tapered such that its diameter is gradually reduced towards the blower port in order to increase air velocity blowing through the blower nozzle. The vacuum nozzle has a constant diameter along its length. Another blower-vacuum device is disclosed in U.S. Pat. No. 6,735,813. The blower-vacuum device includes a fan, a main body and a single nozzle. The main body is formed with a vacuum pathway upstream from the fan and a blower pathway downstream from the fan with respect to the flow of air. The main body is formed with an attachment hole in fluid communication with both the vacuum pathway and the blower pathway. The attachment hole supports the nozzle rotationally between a vacuum mode orientation and a blower mode orientation. U.S. Pat. No. 4,476,607 discloses a lightweight portable vacuum cleaner and attachment nozzle which may be readily carried by an operator to vacuum both normally accessible and normally inaccessible areas. The vacuum cleaner comprises an elbow-shaped plastic housing which encloses a filter bag and blower motor. The vacuum is carried under the arm of the operator supported from a strap that goes over the operator's shoulder. The aforementioned blower-vacuum devices are all provided with a straight vacuum nozzle having a length consistent with safety standards. This means that the vacuum nozzle or the blower/vacuum nozzle generally have a lengthy configuration. However the elongate nozzle leads to blower-vacuum device with a discordant design which makes it difficult to hold with only one handle when the operator converts it between the vacuum mode and the blower mode. SUMMARY OF THE INVENTION In order to overcomes certain disadvantages of the prior art, it is an object of the present invention to provide an improved blower-vacuum design which minimizes the length of the vacuum nozzle, whilst making the vacuum more effective and its operating more comfortable. Thus viewed from the present invention provides a blower-vacuum device comprising: a main body; a motor operated by a switch which is housed in the main body; a motor-driven fan capable of generating an air flow; a vacuum nozzle associated with the main body upstream of the motor-driven fan and a blower nozzle associated with the main body downstream of the motor-driven fan, wherein the vacuum nozzle comprises an elongate main portion extending substantially coaxially with an axis Z 1 of the main body and a terminal portion extending along an axis Z 2 angularly with respect to the axis Z 1 of the main body. The vacuum nozzle may have a non-linear configuration. The configuration may be flat, tapered, round, trapezoidal or curved. The axis Z 2 may be offset from the axis of the fan. The blower nozzle may have any non-linear configuration. The configuration may be flat, tapered, round, trapezoidal or curved. Typically the angle β between the axis Z 1 and the axis Z 2 is obtuse. Preferably the angle is in the range 90 to 180°, particularly preferably 120 to 150°. Preferably the terminal portion extends along an axis Z 2 angularly away from the blower nozzle (eg upwardly away from the ground). The vacuum nozzle may be positioned superior to (eg over) the blower nozzle. The blower nozzle may be positioned superior to (eg over) the vacuum nozzle. Typically the terminal portion, the elongate main portion and the blower nozzle are substantially coplanar. Preferably the length of the terminal portion is in the range 5 mm to 1 m. Preferably the vacuum nozzle is positioned superior to (eg over) the blower nozzle. Particularly preferably the vacuum nozzle is positioned superior to the blower nozzle and the vacuum nozzle has a deflection point, wherein the blower nozzle has a blower port at its distal end substantially adjacent to the deflection point. Preferably the blower port is tapered substantially equiangularly to the angle β between the axis Z 1 and the axis Z 2 Preferably the vacuum nozzle and the blower nozzle are detachably associated with the main body and the vacuum nozzle is fixed to the blower nozzle. Preferably the main body comprises: a motor housing the motor and a volute housing the fan, wherein the motor housing is formed integrally with the volute housing. Preferably the blower-vacuum device further comprises: a handle assembly, wherein the handle assembly comprises: a first grip section disposed on the main body and a second grip section disposed on the vacuum nozzle. Preferably the blower-vacuum device further comprises: a safety interlock, wherein the safety interlock is disposed between the first grip section and the second grip section such that only when the vacuum nozzle is attached to the main body is the motor activatable and only when the motor is inactive is the vacuum nozzle detachable. Preferably the blower-vacuum device further comprises: a variable airflow adjustment including an aperture in the blower nozzle and a rotatable collar mounted rotationally about the blower nozzle over the aperture. Preferably the blower-vacuum device further comprises: an airflow guide mechanism disposed between the vacuum nozzle and blower nozzle for guiding the airflow blowout from the aperture. Viewed from a further aspect the present invention provides a blower-vacuum device comprising: a main body; a motor operated by a switch which is housed in the main body; a motor-driven fan capable of generating an air flow; and a vacuum nozzle associated with the main body upstream of the motor-driven fan and a blower nozzle associated with the main body downstream of the motor-driven fan, wherein the vacuum nozzle is curved and attached superiorly adjacent to the blower nozzle. Viewed from a yet further aspect the present invention provides a blower-vacuum device convertible between a blower mode and a vacuum mode comprising: a main body; a motor operated by a switch which is housed in the main body; a motor-driven fan capable of generating an air flow; a nozzle attachment associated with the main body wherein the nozzle attachment comprises a vacuum nozzle which is curved. The motor may comprise an electric motor, internal combustion engine or other type of power supply The fan may include a debris engaging structure or serrations for facilitating a finer mulch of air-entrained debris. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described in a non-limitative sense with reference to the accompanying Figures in which common reference numerals represent corresponding parts throughout: FIG. 1 illustrates an embodiment of the blower-vacuum device of the present invention; FIG. 2 is a cross-sectional view according to FIG. 1 , wherein the nozzle attachment is disengaged from the main body; FIG. 3 is a cross-sectional view according to FIG. 1 ; FIG. 4A is an enlarged view taken along line A-A in FIG. 1 , wherein the aperture of the blower nozzle is closed by the collar of airflow adjustment; FIG. 4B is an enlarged view taken along line A-A in FIG. 1 , wherein the aperture communicates with the external atmosphere; FIG. 5 is a partial enlarged view according to mark B in FIG. 3 , wherein the interlock mechanism is shown; FIG. 5A is a schematic view according to FIG. 5 , wherein the nozzle attachment is disengaged from the main body; FIG. 5B is a schematic view according to FIG. 5 , wherein the nozzle attachment is engaged with the main body; FIG. 5C is a schematic view according to FIG. 5 , wherein the nozzle attachment is engaged with the main body and the actuator is switched on; FIG. 6A is a schematic view according to the present invention, wherein the user holds the blower-vacuum with one hand in the vacuum mode; and FIG. 6B is a schematic view according to the present invention, wherein the user holds the blower-vacuum with one hand in the blower mode; DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a portable blower-vacuum device 1 according to the invention is illustrated in FIGS. 1 to 3 . The portable blower-vacuum device 1 comprises a main body 2 to which is connected stably and detachably an elongate nozzle attachment 10 and a collecting container (not shown). For the sake of illustration, arrow F indicates the front direction and arrow R indicates the rear direction of the blower-vacuum device 1 . The main body 2 comprises a motor housing 2 a which houses a motor 3 and a volute housing 2 b formed integrally with the motor housing 2 a which houses a fan 4 . The motor 3 imparts a rotational force to the fan 4 via an output shaft 3 a which defines an axis Y. The fan 4 includes a plurality of vanes for generating an air-flow as the fan 4 is driven by the motor 3 . The volute housing 2 b includes an inlet port 30 and an outlet port 31 . The elongate nozzle attachment 10 includes a vacuum nozzle 11 having a vacuum port 11 a at its front end and a blower nozzle 12 having a blower port 12 a at its front end. The vacuum nozzle 11 is connected superiorly adjacent to the blower nozzle 12 and forms a one-piece elongate nozzle attachment 10 . The vacuum nozzle 11 is substantially cylindrical and has a substantially constant diameter along its length. A dust nozzle 15 is connected to and positioned beneath the volute housing 2 b. A rear end of the vacuum nozzle 11 is mounted on the inlet port 30 and a rear end of the blower nozzle 12 is mounted on the outlet port 31 . A safety interlock 20 is disposed between the main body 2 and elongate nozzle attachment 10 to ensure the safety of the operator. An electric cord 6 is attached to the rear end of the motor housing 2 a for supplying power to the motor 3 . A handle assembly 5 comprises an elongate first grip section 5 a defining a first elongate central axis X 1 and a second grip section 5 b defining a second central axis X 2 which are disposed respectively on the main body 2 and the vacuum nozzle 11 . When the elongate nozzle attachment 10 is attached to the main body 2 , the first grip section 5 a is connected to the second grip section 5 b forming an integrated operating handle 5 . The first axis X 1 and the second central axis X 2 form an integrated central axis of the handle assembly 5 . A change-over switch 17 comprises a knob 17 a disposed exteriorly to the main body 2 and a flap 17 b disposed interiorly to the main body 2 for switching the device 1 between the blower mode and the vacuum mode. The operator can select the different operating modes only by rotating the knob 17 a according to the orientations marked on the main body 2 . When the knob 17 a is rotated in a counterclockwise direction from a first position to a second position (which is indicated with a broken line in FIG. 1 ), the flap 17 b engages the upper wall of the blower nozzle 12 so as to shut off the outlet port 31 (as indicated by a broken line in FIG. 3 ). The volute housing 2 b is in communication with the dust nozzle 15 and out of communication with the blower nozzle 12 . This arrangement constitutes the vacuum mode. By rotation of the knob 17 a in a clockwise direction, the flap 17 b engages a wall of the dust nozzle 15 . Thus the outlet port 31 is opened and the volute housing 2 b is in communication with the blower nozzle 12 . This arrangement constitutes the blower mode in which the fan 4 rotates (as in the vacuum mode) so that air is sucked through the vacuum port 11 a of the vacuum nozzle 11 and is introduced into the volute housing 2 b . The sucked air passes through the fan 4 and the outlet port 31 and is introduced into the blower nozzle 12 from where it is discharged through the blower port 12 a . The blower nozzle 12 has a tapered cylindrical configuration in which its diameter decreases gradually towards the blower port 12 a such that air velocity blowing from the blower nozzle 12 is higher than air velocity sucked into the vacuum nozzle 11 . Accordingly, larger dust (and other) particles will not be sucked in through the vacuum port 11 a in the blower mode. The vacuum nozzle 11 has a main elongate portion 14 a which extends along a longitudinal axis Z 1 and a deflected end portion 14 b which extends along an axis Z 2 . In this embodiment, an angle β of approximately 145 degrees exists between Z 1 and Z 2 . The length of the blower nozzle 12 is shorter than the vacuum nozzle 11 and the blower port 12 a of the blower nozzle 12 is approximately aligned with the point of deflection of the vacuum nozzle 11 . A variable airflow adjustment 16 is made possible by an aperture 8 in the wall of the blower nozzle 12 . Mounted for rotation about the wall directly over the aperture 8 is a rotatable collar 13 . Referring to FIG. 4A and FIG. 4B , the rotatable collar 13 has a partial apertured portion 13 a . By rotating collar 13 , the whole or a portion of aperture 8 in the tubular wall is exposed via the apertured portion 13 a thereby enabling a preselected amount of airflow to be diverted out of the side of the wall to alter the airflow which is discharged from the blower port 12 a . An airflow guide mechanism 9 is disposed between the vacuum nozzle 11 and blower nozzle 12 . The airflow guide mechanism 9 comprises a pair of side plates 9 b which is disposed beneath the vacuum nozzle 11 and on top of the aperture 8 of the blower nozzle 12 . The distance between the two side plates 9 b is slight larger than the aperture 8 . A top plate 9 a formed by the wall of the vacuum nozzle 11 and a back plate 9 c located behind the airflow adjustment 16 are shown in FIG. 3 . Under the normal operating conditions of the blower mode, the airflow discharged from the blower port 12 a is directed at debris such as grass or leaves which are mostly propelled forwardly. Some light debris is blown upwardly or backwards towards the user when the airflow guide mechanism 9 is closed. When the airflow adjustment 16 is opened, communication of the airflow between the aperture 8 and the apertured portion 13 a of the collar 13 causes at least partial air overflow from the blower nozzle 12 through the aperture 8 . The partial airflow will be guided by the airflow guide mechanism 9 and help to blow forwardly from the rear of the blower nozzle 12 a to avoid blowing the user. Thus the user can face and blow the debris to a distant location for removal. Referring to FIG. 5 , a switch 7 is located in the main body 2 . The safety interlock 20 comprises an actuating member 21 slidably mounted on the front end of the first grip section 5 a . The actuating member 21 is movable between a forward “on” position and a rearward “off” position. A locking member 24 is movably disposed in the main body 2 . A sliding unit 22 is disposed between the locking member 24 and the actuating member 21 for selectively engaging the actuating member 21 . The actuating member 21 comprises a key point 21 a for actuating the switch 7 , a stop portion 21 b and a stop portion 21 c . In order to activate the motor 3 , the switch 7 is depressed by the key point 21 a of the actuating member 21 by moving the actuating member 21 forward along the direction indicated as the arrow. The locking member 24 comprises a press portion 24 a which extends over the surface of the grip section 5 a . A hook 24 b engaged with a recess 19 is disposed at a rear end of the second grip section 5 b . The locking member 24 is biased by a spring 25 which is located in the main body 2 for supporting the locking member 24 to move upwardly and downwardly. The sliding unit 22 has a protruding shoulder 22 a disposed in the intermediate portion and a stop portion 22 b disposed at its upper end. The sliding unit 22 is biased by a spring 23 which is disposed under the sliding unit 22 . In addition, an extending block 18 is disposed on the second grip section 5 b of the nozzle attachment 10 (shown in FIG. 2 ) for selectively engaging the protruding shoulder 22 a of the sliding unit 22 . Referring to FIG. 5A , when the elongate nozzle attachment 10 disengages the main body 2 , the sliding unit 22 biased by the spring 23 is located at its first position. The stop portion 22 b of the sliding unit 22 engages the stop portion 21 b of the actuating member 21 for preventing the movement of the actuating member 21 . The locking member 24 is located at its first position biased by the spring 25 . Referring to FIG. 5B , when the elongate nozzle attachment 10 is attached to the main body 2 , it drives the sliding unit 22 to slide downwards to its second position against the action of the spring 23 by engaging the extending block 18 with the protruding shoulder 22 a of the sliding unit 22 . Thus the stop portion 22 b of the sliding unit 22 disengages the stop portion 21 b of the actuating member 21 and the actuating member 21 can move forward along the direction indicated by the arrow to actuate the switch 7 . Referring to FIG. 5C , the actuating member 21 has moved forward to its “on” position and activated the switch 7 through the key point 21 a of the actuating member 21 . At the same time, the end portion 21 b and stop portion 21 c are located between the sliding unit 22 and the locking member 24 . The end portion 21 b is engaged with the stop portion 22 b . The end portion 21 b prevents the press portion 24 a moving downwardly by depressing the press portion 24 a . Thus the elongate nozzle attachment 10 is held securely to the main body 2 by the hook 24 b and the recess 19 of the second grip section 5 b. Only when the actuating member 21 is moved backwards to its “off” position can the press portion 24 a be depressed to release the elongate nozzle attachment 10 from the main body 2 . The user holds the first grip section 5 a with one hand and the second grip section 5 b with the other hand to depress the press portion 24 a with his thumb. The hook 24 b disengages the recess 19 of the second grip section 5 b . When the elongate nozzle attachment 10 is detached from the main body 2 , the sliding unit 22 is urged into its first position ( FIG. 5A ) by the spring 23 to prevent the actuating member 21 from movement. Thus the motor 3 cannot be actuated by the switch 7 and the safety of the operator is ensured. Only when the elongate nozzle attachment 10 is attached to the main body 2 can the motor 3 be actuated by the switch 7 through movement of the actuating member 21 . The volute housing 2 b and the fan 4 can be maintained only through removing the elongate nozzle attachment 10 from the main body 2 . The detachable connection between the nozzle attachment 10 and main body 2 makes the packaging convenient. Referring to FIG. 6A , the blower-vacuum device 1 is in vacuum mode. The vacuum port 11 a and blower port 12 a are close to the ground and terminate substantially in the same plane parallel to the ground. The height H of the blower nozzle 12 and vacuum nozzle 11 along the perpendicular direction is substantially equivalent. The construction of the elongate nozzle attachment 10 makes the centre of gravity of the blower-vacuum device 1 lower. Because of the elongate configuration of the first grip section 5 a , the user can adjust to different positions according to requirements. The user can operate the blower-vacuum device 1 with one hand only and a comfortable operating position can be obtained easily. Referring to FIG. 6B , the blower-vacuum device 1 is in blower mode. The user holds the first grip section 5 a with one hand but the holding position has changed with respect to the vacuum mode. The blower-vacuum device 1 is elevated to make the operating position more comfortable.	The present invention relates to a portable blower-vacuum device which comprises a motor ( 3 ) operated by a switch ( 7 ) and located in a main body ( 2 ) and a fan ( 4 ) drivable by the motor. A vacuum nozzle ( 11 ) and a blower nozzle ( 12 ) are associated with the main body and the vacuum nozzle comprises a main portion ( 14 a ) extending in a direction of an axis (Z 1 ) of the main portion and a terminal portion ( 14 b ) with an axis (Z 2 ) angularly disposed with respect to the axis (Z 1 ) of the main portion.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of co-pending U.S. patent application Ser. No. 10/738,950, which is a continuation of U.S. patent application Ser. No. 10/354,226, filed on Jan. 29, 2003, which is a continuation of issued U.S. Pat. No. 6,527,047, issued Mar. 4, 2003, which claims priority to PCT/GB99/02704, filed on Aug. 16, 1999, which claims benefit of GB 9818366.8 filed Aug. 24, 1998, in Great Britain. Each of the aforementioned related patent applications is herein incorporated by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to a method and apparatus for facilitating the connection of tubulars using a top drive and is, more particularly but not exclusively, for facilitating the connection of a section or stand of casing to a string or casing. [0004] 2. Description of the Related Art [0005] In the construction of wells such as oil or gas wells, it is usually necessary to line predrilied holes with a string of tubulars known as casing. Because of the size of the casing required, sections or stands of say two sections of casing are connected to each other as they are lowered into the well from a platform. The first section or stand of casing is lowered into the well and is usually restrained from falling into the well by a spider located in the platform's floor. Subsequent sections or stands of casing are moved from a rack to the well centre above the spider. The threaded pin of the section or stand of casing to be connected is located over the threaded box of the casing in the well to form a string of casing. The connection is made-up by rotation therebetween. [0006] It is common practice to use a power tong to torque the connection up to a predetermined torque in order to perfect the connection. The power tong is located on the platform, either on rails, or hung from a derrick on a chain. However, it has recently been proposed to use a top drive for making such connection. [0007] Prior to the present invention, pipe handling devices moved pipes to be connected to a tubular string from a rack to the well centre using articulated arms or, more commonly, a pipe elevator suspended from the drilling tower. [0008] The present invention provides an alternative to these devices. SUMMARY OF THE INVENTION [0009] Accordingly, a first aspect of the present invention provides an apparatus for facilitating the connection of tubulars, said apparatus comprising a winch, at least one wire line and a device for gripping a tubular the arrangement being such that, in use, the winch can be used to winch said at least one wire and said device to position a tubular below said top drive. [0010] Further features are set out in claims 2 to 6 . [0011] According to a second aspect of the present invention there is provided a method of facilitating the connection of tubulars using a top drive and comprising the steps of attaching at least one wire to a tubular, the wire depending from the top drive or from a component attached thereto, and winching the wire and the tubular upwards to a position beneath the top drive. [0012] According to a third aspect of the present invention there is provided an apparatus for facilitating the connection of tubulars using a top drive, said apparatus comprising an elevator and a pair of bails, characterized in that said elevator is, in use, movable in relation to said pair of bails. [0013] According to a fourth aspect of the present invention there is provided: an apparatus for facilitating the connection of tubulars using a top drive, said apparatus comprising an elevator and a pair of bails, characterized in that said elevator is, in use, movable relative to said pair of bails. BRIEF DESCRIPTION OF THE DRAWINGS [0014] For a better understanding of the present invention and in order to show how the same may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which: [0015] FIGS. 1 a to 1 e are perspective views of an apparatus in accordance with a first embodiment of the present invention at various stages of operation; and [0016] FIGS. 2 a to 2 d are perspective views of an apparatus in accordance with a second embodiment of the invention at various stages of operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0017] Referring to FIGS. 1 a to 1 e there is shown an apparatus which is generally identified by reference numeral 1 . [0018] The apparatus 1 comprises a clamp 2 for retaining a tubular 3 . The clamp 2 is suspended on wires 4 , 5 which are connected thereto on opposing sides thereof. The wire 5 passes through an eye 6 in lug 7 which is attached to a spherical bearing in arm 8 of a suspension unit 9 at the point at which the arm 8 is connected to a hydraulic motor. The wire is connected to the hydraulic motor 10 in a corresponding manner. The suspension unit 9 is of a type which enables displacement of the tubular 3 when connected to a tool 17 (see below), relative to a top drive 13 , along a number of different axes. The wires 4 , 5 pass across the suspension unit 9 and over pulley wheels 11 which are rotatably arranged on a plate 12 . The plate 12 is fixed in relation to a top drive generally identified by reference numeral 13 . The wires 4 , 5 then pass over drums 14 to which the wires 4 , 5 are also connected. The drums 14 are rotatable via a hydraulic winch motor 15 . [0019] In use, the clamp 2 is placed around a tubular below a box 16 thereof. The hydraulic winch motor 15 is then activated, which lifts the tubular 3 (conveniently from a rack) and towards a tool 17 for gripping the tubular 3 ( FIG. 1 b ). The tubular 3 encompasses the tool 17 at which point the hydraulic winch motor 15 is deactivated ( FIG. 1 c ). During this operation the elevator 18 is held away from the tool 17 by piston and cylinders 19 , 20 acting on bails 21 and 22 . The suspension unit 9 allows the hydraulic motor 10 and the arrangement depending therebelow to move in vertical and horizontal planes relative to the top drive 13 . The eyes 6 in lugs 7 maintain the wires 4 and 5 in line with the tubular 3 during any such movement. The tool 17 may now be used to connect the tubular to the tubular string. More particularly, the tool may be of a type which is inserted into the upper end of the tubular, with gripping elements of the tool being radially displaceable for engagement with the inner wall of the tubular so as to secure the tubular to the tool. Once the tool is secured to the tubular, the hydraulic motor 10 is activated which rotates the tool 17 and hence the tubular 3 for engagement with a tubular string held in a spider. [0020] The clamp 2 is now released from the tubular 3 , and the top drive 13 and hence apparatus 1 is now lifted clear of the tubular 3 . The elevator 18 is now swung in line with the apparatus 1 by actuation of the piston and cylinders 19 and 20 ( FIG. 1 d ). [0021] The top drive 13 is then lowered, lowering the elevator 18 over the box 16 of the tubular 3 . The slips in the elevator 18 are then set to take the weight of the entire tubular string. The top drive is then raised slightly to enable the slips in the spider to be released and the top drive is then lowered to introduce the tubular string into the borehole. [0022] Referring to FIGS. 2 a to 2 d there is shown an apparatus which is generally identified by reference numeral 101 . [0023] The apparatus 101 comprises an elevator 102 arranged at one end of bails 103 , 104 . The bails 103 , 104 are movably attached to a top drive 105 via axles 106 which are located in eyes 107 in the other end of the bails 103 , 104 . Piston and cylinders 108 , 109 are arranged between the top drive 105 and the bails. One end of the piston and cylinders 108 , 109 are movably arranged on axles 110 on the top drive. The other end of the piston and cylinders 108 , 109 are movably arranged on axles 111 , 112 which are located in lugs 113 , 114 located approximately one-third along the length of the bails 103 , 109 . [0024] The elevator 102 is provided with pins 115 on either side thereof and projecting therefrom. The pins 115 are located in slots 116 and 116 g . A piston 117 , 118 and cylinder 119 , 120 are arranged in each of the bails 103 , 104 . The cylinders are arranged in slot 121 , 122 . The piston 117 , 118 are connected at their ends to the pins 115 . The cylinders 119 , 120 are prevented from moving along the bails 103 , 104 by cross members 123 and 124 . A hole is provided in each of the cross members to allow the pistons to move therethrough. [0025] In use, a tubular 125 is angled from a rack near to the well centre. The tubular may however remain upright in the rack. The clamp 102 is placed around the tubular below a box 126 ( FIG. 2 a ). The top drive is raised on a track on a derrick. The tubular is lifted from the rack and the tubular swings to hang vertically ( FIG. 2 b ). The piston and cylinders 108 , 109 are actuated, extending the pistons allowing the bails 103 , 104 to move to a vertical position. The tubular 125 is now directly beneath a tool 127 for internally gripping and rotating the tubular 125 ( FIG. 2 c ). The pistons 117 , 118 and cylinders 119 , 120 are now actuated. The pins 115 follow slot 116 and the clamp 102 moves upwardly, lifting the tubular 125 over the tool 127 ( FIG. 2 d ). The tool 127 can now be actuated to grip the tubular 125 . [0026] At this stage the elevator 102 is released and the top drive 105 lowered to enable the tubular 125 to be connected to the string of tubulars in the slips and torqued appropriately by the top drive 105 . [0027] The pistons 117 , 118 and cylinders 119 , 120 are meantime extended so that after the tubular 125 has been connected the top drive 105 can be raised until the elevator 102 is immediately below the box. The elevator 102 is then actuated to grip the tubular 125 firmly. The top drive 105 is then raised to lift the tubular string sufficiently to enable the wedges in the slips to be withdrawn. The top drive 105 is then lower to the drilling platform, the slips applied, the elevator 102 raised for the tubular 125 and the process repeated. [0028] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.	An apparatus for facilitating the connection of tubulars, said apparatus comprising a winch, at least one wire line, and a device for gripping the tubular, the arrangement being such that, in use, the winch can be used to winch said at least one wire and said device to position a tubular below said top drive.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATION This patent application claims priority to U.S. Provisional Patent Application No. 60/618,019 filed on Oct. 12, 2004, entitled Electromechanical Door Solenoid Current Surge Booster Circuit, which is incorporated herein by reference. FIELD OF THE INVENTION This invention relates to electromechanical door opening devices and more particularly to a method and apparatus for a supplying power to an electromechanical door latch actuator. BACKGROUND OF THE INVENTION Electromechanical security door lock mechanisms actuated by solenoids are ubiquitous. A typical lock mechanism allows a user on one side of a door to mechanically actuate the locking mechanism to release the lock while requiring a user on the other side of the door to actuate it electromechanically with a security device such as a key, a card reader, or a keypad requiring that a password, number or word be entered. Panic exit devices, for example, employ a mechanical latch release mechanism that allows a user on the egress side of a door to mechanically actuate the mechanism as a fail-safe release for the door latch to allow exit from a room. The Von Duprin company of Indianapolis, Ind. makes several such devices and related components such as their 33A/35A and 98/99 Series Exit Devices. A panic exit device may also be equipped to be actuated electromechanically with a solenoid to allow a person on the opposite ingress side of the door to operate the latching mechanism electrically. A user attempting to operate the latching mechanism from the ingress side might be required to use an electronic security device to gain access such as a card reader or keypad to electromechanically release the latch mechanism. The Sargent Manufacturing Company of New Haven, Conn. makes various electromechanical latching devices using a solenoid actuator, their Series 80 product line is similar to that of the Von Duprin 33A/35A and 98/99 Series products. In some applications the egress latching mechanism may be operated by employing an electromechanical latching mechanism as well, using a solenoid to operate the latching mechanism. These electromechanical latching devices use a solenoid to actuate the latching mechanism in the door, to move it from a first closed or locked position to a second open or unlocked position. Solenoids are widely used operate a variety of electromechanical door latch configurations. The above panic exit devices for example may be configured to be used with a latching mechanism that includes vertical rods, roller (horizontal) rods, or with rim or mortised types of latching mechanisms. Exemplary prior art designs for latching devices and components of analogous construction are shown in Zawadski U.S. Pat. No. 3,767,238 entitled Push Plate Panic Exit Device and Godec et al, U.S. Pat. No. 4,167,280 entitled Panic Exit Mechanism. These electromechanical door latching mechanisms require a separate power supply to supply current to operate the solenoid. A typical power supply for a solenoid of the prior art is located at a distance from the latching mechanism on the door itself. A typical power supply is a transformer used to convert 120 or 220 VAC input current to a safe 24 VDC output current to operate the solenoid at its required current load. The solenoids used with these devices require a substantial momentary current load for an interval of time to move the latching mechanism. A solenoid used in door latches typically include primary and secondary coils that move an armature or plunger and hold the armature of the solenoid in the moved position. The armature is connected to a latching mechanism and the primary solenoid coil causes the armature to move the latching mechanism from a first locked or closed position to a second unlocked or open position. The secondary coil thereafter retains the armature and latching mechanism in the unlocked configuration. Latching mechanisms are typically biased with a spring to return the latching mechanism to the closed or locked position after power to the secondary coil is removed. The primary coil of a solenoid for a door actuator is typically operated for a load interval of about 10-200 msec at 20-30 VDC, depending on the solenoid being used. The secondary coil requires only perhaps half an ampere at to retain the latching mechanism in an unlocked configuration thereafter. These devices have proved very useful and successful over the years. Panic exit and security entry devices are a critical part of any fire and safety system and providing restricted access and safe and reliable egress from a building in the event of a fire or power failure. Such devices are frequently required by local fire safety and building codes. A longstanding problem with the prior art is that the power supply for the latching mechanism must be able to supply power at an acceptably safe lower voltage and with sufficient current to meet the inrush surge current load drawn during actuation of the primary coil of the solenoid. Because the current must be maintained at a safer lower typically 24 VDC voltage to prevent electrocution, the effects of resistance and voltage drop are increased in the transmission of power from the power supply to the solenoid over a transmission wire. Because the output voltage of the power supply must be kept low the effects of resistance and particularly voltage drop in the wire connecting the power supply to the solenoid must be minimized. Voltage drop is also increased as the power supply is located at greater distances from the solenoid, this requires that the power supply be situated relatively close to the solenoid. Typically the transmission wire connecting the power supply to the door latch solenoid cannot exceed more than twenty-five feet in length and therefore presents an inherent design limitation. Voltage drop and resistance are also proportional to wire size and the voltage drop in connecting transmission wire has been minimized in the prior art by using a larger gauge wire to connect the power supply to the solenoid. Standard 18-gauge electrical wiring used in buildings is usually unsuitable for carrying the needed momentary current surge load between the power supply and the solenoid of a door latch mechanism so heavier gauge wiring, 12-gauge wire for example, is typically used instead. This heavier wire must be specially installed in the walls between the power supply and the solenoid of the door. The need to install heavier gauge wiring to carry current between the power supply and the door solenoid is costly and laborious. What is needed then is a way to reduce voltage drop in the transmission wire without the necessity of using heavier gauge wire and without the necessity the need for the power supply be in such close proximity to the solenoid. This would allow for a wider choice of locations for the power supply and be more economical as well because a lighter gauge wire may be used. Further objects and advantages of the invention will become apparent to one skilled in the art by reading and understanding the following summary, detailed description and the drawings to which it refers. SUMMARY OF THE INVENTION A solution to the above has been devised. The power supply is located on one end of the transmission wire and a capacitor connected to the solenoid is located on the other end of the transmission wire, adjacent to the door latching mechanism. The capacitor provides a current reserve that may be drawn on when the primary coil is activated, greatly reducing the current capacity needed to be carried over the transmission wire. This current boost by the capacitor allows sufficient additional current to be delivered to the solenoid to momentarily operate the primary coil to move the latching mechanism from a locked to an unlocked position. In the preferred embodiment the booster circuit of the present invention includes the capacitor and circuitry to monitor voltage in the system and to time and switch the primary coil on and off. The booster circuit is located on the door, close to or directly adjacent the solenoid. The problem of voltage drop due to the distance between the power supply and solenoid is thus reduced. The use and placement of a booster circuit in this manner decreases the need for heavier gauge wiring and to have the power supply located so close to the door. Because the power supply may be located at a greater distance from the latching mechanism a wider variety of design choices is allowed for placing the power supply. Voltage drop is much less of a problem because the transmission line current load is less. The capacitor and secondary coil are charged with a relatively steady current from the power supply and the secondary coil only draws about half an ampere. The power supply and transmission wire then need only be suitable for carrying current sufficient to charge the capacitor and power the secondary coil. In the preferred embodiment the circuitry used to control the capacitor includes a micro controller that monitors the voltage charge of the capacitor and times a primary coil ignition delay cycle beginning from when the power supply is activated. The power supply may be switched on when a user presses on the panic bar or when a security device such as a keypad is used to switch on the power supply. For a given solenoid and latching mechanism a capacitor must reach an optimum voltage charge to ensure there is sufficient reserve current for proper solenoid operation. The capacitor must achieve at least a minimum voltage to operate the solenoid at all and the optimum voltage is generally higher than the minimum voltage. When the power supply is turned it both charges the capacitor and the secondary coil of the solenoid. The micro controller measures the increasing voltage of the charge on the capacitor over time and, when the capacitor either reaches the predetermined optimum voltage, or, when a preset ignition delay time period has elapsed together with the capacitor having at least reached the predetermined minimum voltage, the micro controller switches on the primary coil for a set period of time, the load interval. Current from the capacitor supplements the current supplied by the power supply to provide the boost needed to meet the increased current load drawn by the primary coil, to move the door latching mechanism to the open or unlocked position. The circuit does not switch on the primary coil of the solenoid at all unless the threshold minimum voltage has been reached. After the primary coil has been supplied with current for a preset brief load interval period of time the micro controller switches off the primary coil and the capacitor recharges. When the power supply current is removed the micro controller causes the capacitor to fully discharge, by briefly activating the primary coil for example. This final discharge of the capacitor is performed to prevent the reserve current in the capacitor from continuing to supply power to the secondary coil after the power supply has been removed, and thereby hold the latching mechanism in an open or unlocked position after the power supply has been removed. The capacitor would continue to supply power to the solenoid as its charge dissipates. After the power supply current has been removed and the capacitor has been sufficiently discharged the latching mechanism returns to a closed or locked position. This construction allows for door latching operation without the need for a higher capacity power supply that must be in such close proximity to the latching mechanism and without the need for the use of a larger gauge transmission wire. The use of the present invention allows the power supply to be placed at much greater distances from the latching mechanism, perhaps 250 feet, allowing a wider choice of power supply locations. The elimination of the need for heavier gauge wiring is particularly useful for retrofitting electromechanical door latching devices in existing buildings because existing smaller transmission wire may be used. Use of a micro controller in the booster circuit also allows the device of the present invention to be programmed to be used with a multitude of existing door actuating devices and panic exit devices made by different manufacturers. The minimum and optimum voltage charge levels, as well as the ignition delay before switching on the primary coil, may be adjusted for properly supplying power to a given solenoid. In this respect, before explaining at least one embodiment of the invention in detail it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B are front perspective views of latching mechanisms of the prior art that may be used in conjunction with the present invention. FIG. 1C is a schematic view of an electromechanical door latching device of the prior art that is used with the devices of FIGS. 1A and 1B . FIG. 2A is a perspective view of an embodiment of an electromechanical door latching device of the present invention. FIG. 2B is a schematic view of an embodiment of an electromechanical door latching device of the present invention. FIG. 3 is a flow chart of methods of the present invention. FIG. 4 is a circuit diagram of an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The following detailed description, and the figures to which it refers, are provided for the purpose of describing example(s) and specific embodiment(s) of the invention only and are not intended to exhaustively describe all possible examples and embodiments of the invention. Referring now to FIGS. 1A , 1 B and 1 C front and schematic views are shown of the general attributes of typical latching devices of the prior art with which the present invention may be used. FIG. 1A is a view of a mortise type latching mechanism actuated by a touch plate that is mounted on a portion of a door; FIG. 1B is a view of a vertical rod type of latching mechanism. FIG. 1C is a side schematic view of a rim type latching mechanism. These different types of door latching mechanisms are presented by way of example to display the variety of latching mechanisms used and not so as to limit the scope of the invention. The present invention may be used with other electromechanical door latching configurations incorporating a solenoid, such as horizontal roller door latching mechanisms. Panic exit door latching device 9 has a housing 11 mounted on a door 10 and having a touch plate 13 supported for movement outwardly and inwardly that is coupled to a switch (not shown) to activate a latch bolt actuator assembly 21 . The touch plate 13 , when pressed, actuates a two-stage solenoid 17 , having primary and secondary coils (not shown) that move an armature 19 linked to the latch bolt actuator mechanism 21 . In the first stage the primary coil the of solenoid 17 retracts the solenoid armature 19 . The armature 19 is coupled to the latch bolt actuator assembly 21 providing an operative connection between the armature of the solenoid and a locking bolt 22 . This first stage of operation of moving the armature of the solenoid requires a substantial electrical current draw from a power supply 23 . Power from the power supply 23 is switched on with high current relay switch 33 . A typical power supply 23 is rated to momentarily supply several amperes at 24 VDC or twice that amount at 12 VDC to actuate the solenoid. Thereafter in a second hold stage the secondary coil of the solenoid holds the latch in a retracted state until such time as it has been programmed or timed to release. A security device such as a keypad or a card reader may be used in conjunction with operation of the circuit if the door latching device 9 to allow selective access through the door. Electrical current is supplied to the solenoid 17 with transmission wiring 16 that is threaded through the device and the interior of the door itself to a separate power supply 23 . The wiring to a typical separate power supply 23 requires the use of 16 heavier gauge transmission wire than is ordinarily used for standard electrical circuits in a building. 12-gauge wire is typically used owing to the substantial electrical current draw needed by the solenoid for the first stage of the latch opening process. In the second stage of the latch opening process the solenoid armature is retained in the open position by a secondary coil requiring much less current. FIG. 2A is a perspective view of an embodiment of an electromechanical door latching device using a booster circuit of the present invention. A rim type of panic exit door latching device 9 of including the present in invention is shown. The capacitor 29 is mounted within the housing 11 and is in electrical communication with the solenoid 17 . FIG. 2B is a schematic view of an embodiment of the invention as used with the panic exit door latching device of FIG. 2A . No special high capacity power supply is needed and instead a smaller power supply 31 may be used. In most applications a power supply of at least about 1-2 amperes capacity is sufficient. In a typical application the supply voltage is about 20-30 VDC. In the preferred embodiment the circuit monitoring the charge of the capacitor includes a 68HC908QT2 micro controller made by the Motorola corporation of Santa Clara, Calif. This micro controller includes 1.5K bytes of in-application reprogram able flash ROM and 128K bytes of RAM. Standard assembly code is used to program a timed cycle with the micro controller to monitor the voltage of the capacitor as it is charged and discharged and to fully discharge the capacitor to fully deactivate the solenoid at the end of the cycle. The method of the present invention is shown in FIG. 3 . The micro controller of the booster circuit is programmed to switch on the primary coil of the solenoid after one of two conditions exists. The micro controller will switch on the primary coil either when the capacitor voltage reaches the threshold of a preset optimum voltage charge, 22 VDC in this embodiment, or if a minimum capacitor voltage, 20 volts in this embodiment, has been reached and also a maximum ignition delay period of time has elapsed after the power supply is activated, after half a second in this embodiment. The micro controller then switches the primary coil off after a preset period of time, the load interval, in this embodiment about 100 msecs. If the minimum voltage has not been reached the primary coil will not be switched on. The micro controller is further programmed to fully discharge the capacitor after current from the power supply is removed, in this embodiment by switching the primary coil on again, to prevent the secondary coil from remaining on from current remaining in the capacitor. Voltage drop loss in the wiring between the power supply 31 and the latching device 9 is no longer a significant problem with the method and design of the present invention. A smaller gauge wire may be used for the wiring between the power supply 16 as well, eliminating the need for special retrofitting of the electrical system of a building. FIG. 4 is a circuit diagram of a preferred embodiment of the circuit of the invention, to be used with generally available latching devices. FIG. 4 is a preferred embodiment of the circuit of the present invention and designed to work with Von Duprin types of electric latch retractors, such models EL 33 and EL 99. A 24 VDC power supply 31 supplies current to a high current relay switch 33 . The switch 33 may be mechanical or an electronic equivalent, such as an electronic switch implemented with a Metal-oxide semiconductor field-effect transistor (MOSFET). The capacitor 29 is sized to be used with a particular model, in this example a 22,000 microfarad capacitor with 35 volts maximum is used. Because the circuit includes a programmable micro controller 35 , the circuit can be programmed to accommodate the specific characteristics of a specific latching mechanism having a capacitor of a given size. In this embodiment the micro controller monitors the charge on the capacitor, shown here at voltage divider checkpoints 37 A and 37 B corresponding to inputs A 0 and A 2 of the micro controller 35 in the circuit of FIG. 4 , by measuring the rate of increase in capacitor charge voltage over time. The micro controller 35 switches on the primary coil of the solenoid with driver 39 either when the capacitor reaches a preset optimum capacitor voltage, or when a half second ignition delay has elapsed and the capacitor has reached at least a preset minimum voltage, supplying the solenoid 32 with a boost or reservoir of current for the primary coil draw on to retract the latching mechanism from a default locked configuration to an open configuration. In the open configuration the latching mechanism is typically tensioned by spring 30 (shown in FIG. 2B ) or other retraction mechanism to return it to the default closed position. During the load interval the micro controller times the discharge of the capacitor supplying the solenoid and switches off the primary coil after a set period of time, 100 msecs in this embodiment. When power from the power supply is removed, the micro controller again switches on the primary coil in order to fully discharge the capacitor. It will be appreciated that the invention has been described hereabove with reference to certain examples or preferred embodiments as shown in the drawings. Various additions, deletions, changes and alterations may be made to the above-described embodiments and examples without departing from the intended spirit and scope of this invention. Accordingly, it is intended that all such additions, deletions, changes and alterations be included within the scope of claims to this invention.	An apparatus, circuit and method for operating a solenoid-actuated electromechanical door latching mechanism that includes a capacitor to meet the power surge requirements needed to move a door latching mechanism. A power supply at one end of a transmission line is coupled with a capacitor adjacent the solenoid at the other end of the transmission line to reduce the need for a larger capacity power, heavy gauge transmission lines and increases the distance at which a power supply may be located from a door latching device.
You are an expert at summarizing long articles. Proceed to summarize the following text: This is a continuation of application Ser. No. 638,437, filed Dec. 8, 1975, now abandoned. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention pertains to a pre-torqued jarring tool utilized to prevent sticking of a drill string in a drilling operation or to remove a stuck pipe or "fish" downstream of the jarring tool. 2. Description of the Prior Art Many jarring tools have been devised for releasing a stuck drill string or for use in retrieving "fish" such as drill pipe or tools which are stuck in a well bore. Such jarring devices are designed to produce an upward or downward jarring action to the stuck drill bit or to the fish or lost part in order to release the stuck element and continue drilling operations. These jarring tools generally utilize a hammer and anvil arrangement of telescoping sections to impart the jarring force. Jarring tools may range from a simple construction such as that shown in McCullough U.S. Pat. No. 2,029,579 to sophisticated hydraulic mechanisms such as those taught by Berryman U.S. Pat. Nos. 3,735,827 and 3,797,591. Prior art jarring tools have been developed with adjustable triggering mechanisms so that the jarring action takes place at different compressional or tensile forces placed on the drill or fishing string. Illustrations of such adjustable triggering mechanisms are shown, for example, in the McCullough U.S. Pat. No. 2,008,765, Raymond U.S. Pat. No 2,144,810 and Nutter U.S. Pat. No. 3,685,598. In these prior art devices, it is possible to adjust the triggering mechanism and consequently the force of the jarring action while the jarring tool is positioned within the well bore. The adjustable triggering mechanisms associated with prior art jarring tools comprise various adjustable spring mechanisms and clutches or, in some cases, hydraulic valve systems. These prior art devices are complex, prone to mechanical failure and are expensive to manufacture and operate. Perhaps the simplest jarring tool devised is the McCullough tool as shown and described in U.S. Pat. No. 2,029,579. The jarring tool described therein is particularly advantageous due to its simplicity of construction and reliability of operation. A prime disadvantage, however, in utilizing such a tool is the inability to pre-torque the tool and to vary the amount of torque as a function of the medium being drilled. Thus, while it is advantageous to utilize the simple mechanism as taught by McCullough, the practical difficulties encountered in stopping the drilling process to apply torque to the drill string prevents the economical and efficient operation of the McCullough device in many drilling operations. For example, the McCullough tool is particularly prone to hydrostatic sticking, which may occur along the entire drill string, if the drilling process is at all interrupted before the jarring action takes place. Thus, the necessity for torquing the drill string at the surface upon any momentary stoppage of the drilling process renders this simple McCullough jarring tool ineffective particularly in high viscosity mediums which are present, for example, in the highly productive Mideast oil fields. SUMMARY OF THE INVENTION It is therefore an object of the invention to eliminate the disadvantages of the prior art jarring tools by providing an immediate jarring action utilizing a pre-torqued jarring instrument. A further object of the invention is to provide an adjustable pre-torqued jarring instrument which may be preloaded in the field in order to achieve greater or lesser jarring forces dependent upon the medium viscosity in the well bore. A further object of the invention is to provide a simple torque assembly for preloading the jarring tool of the type described in McCullough U.S. Pat. No. 2,029,579. A further object of the invention is to provide a jarring tool which may be inserted anywhere in a drill or fishing string. Yet another object of the invention is to provide a simple hammer and anvil jarring tool which does not utilize complicated coiled springs or hydraulic mechanisms to achieve an adjustable preloading of the jarring mechanism. Yet another object of the invention is to provide a jarring tool which eliminates hydrostatic sticking by providing an immediate jarring action upon compressional or tensile forces exceeding adjustable threshold limits. A further object of the invention is to provide an adjustable threshold triggering mechanism for compressional and tensile forces along the drill string. The invention comprises hammer and anvil sections which are movable in telescoping fashion relative to one another and are provided with a pre-torquing means which itself may be adjusted to provide various triggering levels. The telescoping sections are latched together by means of teeth having inclined engaged surfaces which disengage upon the application of a predetermined tensile or compressional force. Disengagement of the teeth renders the hammer section movable longitudinally with respect to the anvil section and thereby supplies the jarring action to the drill or fishing string. The teeth of the respective hammer and anvil sections are biased together utilizing the torquing means so as to maintain a continual force between the teeth thereby continually preloading the jarring tool for instantaneous action if the compressional or tensile forces exceed the threshold limits. The threshold limits are adjustable by applying different amounts of torque to a torque tube connected to one member of the hammer and anvil pair. The torque is adjustable in the field and does not require dismantling of the jarring tool. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of the invention will become more apparent in view of the following description taken in conjunction with the drawings wherein: FIG. 1 is an elevational view of the jarring tool as positioned in a drill string; FIG. 2 is an enlarged detail sectional view of the jarring tool illustrating the torquing tube and hammer and anvil sections; FIG. 3 is a side elevational view of the jar means of the instant invention with the outer housing portion shown in section taken along line 3--3 of FIG. 2; FIG. 4 is a cross-sectional view of a portion of the jarring tool taken along line 4--4 of FIG. 2; FIG. 5 is a side elevational view of a portion of the torque assembly of the instant invention with the pipe housing shown in cross section; FIG. 6 shows a side view of the jarring tool with the preloading tongs in position; and FIG. 7 is a top view of the preloading tongs as shown in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As illustrated in FIG. 1, the jarring tool 1 of the instant invention comprises a torque assembly 2 and a jar means 4 connected together in a drill string. The jarring tool may be positioned anywhere within the drill string and as illustrated in FIG. 1, one generally would have additional pipe sections 6 and 7 positioned respectively above and below the jarring tool. In some instances, the pipe section 7 may be a "fish" such as a drill pipe or subsurface tool stuck in the well bore. Additionally, the pipe section 6 may be a top sub (rotary drilling substitute). As illustrated in FIG. 2, the torque assembly 2 comprises a pipe housing 5 which has at its upper end a threaded portion 8 connected to a mating threaded portion 10 of the pipe section 6. The pipe housing 5 has a passageway 12 in which is positioned an elongated torque means in the form of a torque tube 14. The torque tube 14 is torsionally secured to the pipe housing 5 proximate the upper end of housing 5 by clamping means which may comprise a plurality of lugs or cap screws 16 which are threaded into the pipe housing 5 and extend radially into longitudinal recesses or slots 18 milled in the torque tube 14. O-ring seals 19 are provided adjacent the cap screws 16 to prevent leakage of circulation fluids. The torque tube 14 has a central longitudinal fluid passageway 20 which serves as a wash pipe, and torque tube 14 is further positioned centrally of the passageway 12 within the pipe housing 5 by means of a floating bushing or packing 22. As illustrated in the right-hand portion of FIG. 2 with additional reference to FIG. 3, the jar means 4 comprises an outer housing 24 and two telescoping sections A and B. Tubular section A serves as a hammer and stem section B serves as an anvil. It is noted, however, that the jarring tool may be operated in an inverted position from that shown in FIG. 2, and in such cases, the "hammer" function is served by section B whereas the section A becomes the anvil. For ease of description, sections A and B are termed hammer and anvil respectively although this terminology is not meant to be limiting. The upper end of hammer section A contains a threaded portion 30 which is coupled with a mating threaded portion 32 in the lower section of housing 5. Section A contains a slot 34 and an identical but diametrically oppositely disposed slot 35 therethrough. As best illustrated in FIG. 3, slot 34 has an upper end 36 and a lower end 38. Further, slot 34 has a side extension having an upper rounded portion 44 and a lower rounded portion 46 with a plurality of teeth means 48 therebetween. Slots 34 and 35 are designed to contain respective identical, diametrically opposed projecting portions or lugs 50 and 51 which themselves are integrally connected to the anvil section B of the jar means 4; however, to simplify the present description, the details of construction will be set forth primarily with references to the slot 34 and lug 50. Lug 50 has mating teeth means 52 which fit in between the gaps defined by teeth means 48 of section A. Further, lug 50 has an upper end portion 56 and a lower end portion 58 which portions are designed to abut the upper end 36 and lower end 38 respectively of section A during upward and downward jarring action. A lower end 60 of section A also comes in contact with a portion 62 of section B during a downward jarring stroke. The upper and lower ends 36 and 38 respectively of the hammer section A thus define the limit of travel of the hammer section A relative to anvil section B. A portion of anvil section B extends into the tubular section A, and during an upward jarring stroke a lesser portion of section B extends into section A whereas during a downward jarring stroke a greater portion of section B extends into section A. The housing 24 is filled with a lubricating fluid such as oil, and an oil plug 68 is provided in housing 24 for introducing such lubricating fluid. Also provided in outer housing 24 is an air vent 70 utilized to vent air upon filling the housing 24 with lubricating fluid. The anvil section B of the jar means 4 has an upper threaded portion 74 which connects with a lower mating threaded portion 76 of a coupling tube 78. Coupling tube 78 is an extension of torque tube 14. Anvil section B has a lower threaded portion 80 which connects with a mating threaded portion 82 in the downstream pipe section 7. The coupling tube 78 is connected to the torque tube 14 by means of a threaded portion 84 on coupling tube 78 and mating threaded portion 86 on torque tube 14. Floating bushings 88 similar to bushing 22 are provided between an inner wall of the hammer section A and the outer wall of the coupling tube 78. A plurality of oil seals 90 are provided on the lower portion of the anvil section B to seal oil within the housing 24. FIG. 4 is a cross-sectional view of the torque assembly 2 taken along line 4--4 of FIG. 2. The cap screws 16 are shown threaded into pipe housing 5 and extending into the recesses or slots 18 in the outer wall of torque tube 14. A side partial elevational view of the torque assembly 2 is shown in FIG. 5 with the outer housing shown in cross section and with pipe section 6 removed. The cap screws 16 are threaded into the housing 5 until a section thereof extends into the slots 18. Slots 18 have a longitudinal extent somewhat greater than the extent of the downstroke and upstroke of the hammer A relative to the anvil B as defined by the longitudinal extent of movement of lugs 50 and 51 in their respective slots 34 and 35. Thus, the cap screws 16 serve to prevent relative rotation of the torque tube 14 with respect to the pipe housing 5 but nevertheless permit longitudinal motion which takes place during an upward or downward jarring stroke. FIGS. 6 and 7 illustrate the method of preloading or pre-torquing the torque tube utilizing wrenches or tongs. The pipe section 6 is removed and a first tong 92 is anchored against rotation and is secured to the outer housing 5 of the torque assembly 2. A second tong 94 is clamped to the top portion of the torque tube 14 and is rotated via motor means 96 in a counterclockwise direction as shown in FIG. 7. Prior to each increment of rotation, the cap screws 16 are loosened sufficiently so that no portion thereof extends into the slots 18 and the torque tube is therefore not in contact with cap screws 16. A torsional stress is put on torque tube 14 by rotating it in a counterclockwise direction relative to the housing 5. The torque tube 14 may be rotated any multiple of 90° relative to the housing 5 when the torque assembly 2 is provided with four cap screws 16 and corresponding slots 18. However, additional slots may be provided in the torque tube 14 and/or additional cap screws may be utilized so that a finer adjustability of torsional stress may be achieved. Rotation of the torque tube 14 by means of the tongs 92 and 94 biases the teeth means 52 of anvil section B against the teeth means 48 of hammer section A. The amount of rotation of torque tube 14 relative to housing 5 determines the amount of compressional force exerted between the teeth means 52 and 48 and consequently sets the threshold for compressional and tensile forces along the pipe which are required to trigger the jarring operation. OPERATION In operation, the amount of preloading is set in the field utilizing the pre-torquing apparatus as shown in FIGS. 6 and 7. Typically, one might utilize a 90° rotation of the torque tube 14 relative to the housing 5 which may typically set a 45 ton compressional trigger level. However, the amount of rotation will vary depending upon the diameter of the torque tube 14 and housing 5 as well as the particular viscosity of the medium being drilled. Rotation of the torque tube 14 in a counterclockwise direction relative to the housing 5 serves to bias the teeth means 52 of anvil section B against the teeth means of hammer section A in the jar means 4. In a downward jarring situation, the anvil section B becomes temporarily stuck in the medium being drilled and compressional forces are built up along the drill string and are transmitted between sections A and B via teeth means 48 and 52. Teeth means 48 and 52 have inclined edges and are pitched such that the teeth will snap out of engagement after a predetermined threshold longitudinal compressional stress is applied. The amount of compressional stress would of course be a function of the amount of torsional stress established by the preloading rotation of the torque tube 14 in the housing 5. Just prior to release of the teeth means 48 and 52, the hammer section A is forced to rotate a small amount in a right-hand or clockwise direction relative to the anvil section B by the camming action of the engaged inclined surfaces of the teeth means 48 and 52. Upon disengagement of the teeth means, however, the compressional forces exerted on the hammer section A cause it to move forcibly downward until the upper end 36 of slot 34 strikes the upper end portion 56 of lug 50. Additionally, the lower hammer end 60 will strike the lower portion 62 of the anvil section B. The jarring action of the hammer section A against the anvil section B tends to loosen the anvil and free it for subsequent drilling. In order to reset or relatch the jar means 4, the drill string is pulled upward releasing the compressional forces and causing the hammer section A to slide upward relative to the anvil section B until the teeth 48 and 52 are again meshed together as shown in FIG. 3. In the upward jarring action, the tensile forces between the hammer section A and the anvil section B are again transmitted through teeth means 48 and 52. Once the threshold tensile force is reached, the hammer section A will again be cammed by the teeth means 48 and 52 to rotate a small amount in a right-hand sense thereby disengaging teeth means 48 from the teeth means 52 and allowing the hammer section A to travel upward relative to the anvil section B. Hammer A will travel upward until the lower end 38 of slot 34 hits lower end portion 58 of lug 50. The jarring action thus provided will tend to lift the anvil section B upward thereby tending to loosen it. In order to relatch the jar means 4, the drill string is released thereby placing compressional forces on the hammer section A and causing it to move downwardly relative to anvil section B until teeth means 48 and 52 are again meshed as shown in FIG. 3. The jarring tool may thus be utilized to provide repeated upward and/or downward jarring actions to the anvil section B and thus to subsequent pipe sections 7 as well as additional downstream pipe sections. The utilization of the torque tube 14 to maintain a preloading of the jar means 4 enables an immediate triggering of the jar means inasmuch as the jar means does not have to be torqued from the surface as in conventional jarring tools. Additionally, the utilization of the torque tube 14 eliminates any slippage between the teeth means of sections A and B respectively thereby permitting the jarring tool to be positioned deep in a drill string without excessive frictional wear between the teeth means which has been a common problem in conventional jarring tools. The preloading of the jar means 4 by the torque tube 14 is particularly advantageous in preventing hydrostatic sticking along the length of the pipe string as is prevalent in high viscosity drilling mediums. The jarring means 4 is particularly versatile in that it may be positioned as shown in FIG. 2 or it may be positioned in an inverted position so that section A becomes the anvil whereas section B becomes the hammer. The preloaded aspects of the invention are not affected by such inversion. It is also noted that the particular clamping means such as the cap screws 16 and slots 18 utilized to provide torsional stress along the torque tube 14 may be replaced by other mechanical devices such as a splined connection to achieve the same results. The jar means incorporated in the torque tube assembly 2 is particularly simple to manufacture and operate and is not prone to numerous mechanical failures which are prevalent in more complicated jarring tools. The jarring tool may not only be adjustably preloaded in the field, but may be positioned anywhere in the drill string, and operates simply and effectively without complex threaded connections, coiled springs, or hydraulic valves. Although the invention has been described with reference to a preferred embodiment, other modifications and improvements may be made by those of skill in the art and it is intended that the invention cover all such modifications and improvements as defined by the appended claims.	A jarring tool for use in a drill string to prevent sticking of the drill string during drilling operations. The jarring tool has a torque assembly for continually torquing the jar and thus the drilling operation need not be discontinued upon encountering an interfering object. The jarring tool is particularly suited for high viscosity drilling operations and eliminates hydrostatic sticking of the drill string by providing an immediate jarring action utilizing a simple hammer and anvil construction. The jarring tool is also suitable for use in a "fishing" string.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION [0001] The present invention relates in general to subsea wellheads for oil and gas wells, and in particular to a nested stack-down casing hanger configuration which allows the pressure in the intermediate casing annuli to be monitored without penetrating the outer pressure containing housing or casing walls which separate the annuli from the external environment. Although the present invention has particular utility with respect to subsea wells, the invention is also applicable to land and offshore surface drilled wells. [0002] In order to conform to various regulations and to protect life, property, and the environment, it is common practice on surface drilled wells to monitor the pressure in the various casing annuli for sustained casing head pressure (SCP). Pressure containing side outlets are provided in the casing and tubing heads, through which the annulus pressure can be measured. However, because such side outlets themselves create potential leak points, and because of the difficulty in detecting leaks, side penetrations in subsea wellhead housings are usually avoided. Exceptions are made in the regulations for high pressure subsea wells, such that it is required only to monitor pressure in the production annulus. In fact, such body penetrations are actually prohibited by some regulations. In any event, body penetrations in subsea wellheads could create potential hazards greater than those originally addressed by annulus monitoring. [0003] Despite the difficulties inherent in monitoring annulus pressure in subsea wells, regulations have been proposed which would require that the pressure be monitored in every annulus in the well. Thus there is a need for a method of monitoring annulus pressure which does not require penetration of the pressure containing casings or housings. Even in the absence of such regulations, such a method would be most useful and desirable. Several prior art methods for monitoring annulus pressure in subsea wells are described in U.S. Pat. Nos. 5,544,707 and 4,887,672. A more complete discussion of the various regulations and the state of the prior art with respect to annulus pressure monitoring is presented in copending U.S. patent application Ser. No. 09/776,065, which is commonly owned herewith and the entirety of which is hereby incorporated by reference for all purposes. [0004] Typical prior art wellhead systems have utilized a “stack-up” casing hanger configuration. In this type of system, the hanger for each successively smaller diameter casing string is landed on top of the hanger for the next larger casing string. Each hanger is locked and sealed to the wellhead housing bore above the next lower hanger. Thus, as each hanger is installed in the wellhead housing, the next lower hanger (and the associated annulus) becomes inaccessible. [0005] For the purposes of illustration, a typical stack-up subsea wellhead system is shown in FIG. 1. The wellhead system comprises a conductor housing 12 attached atop conductor pipe 18 and locked into permanent guide base 10 . The wellhead housing 14 is landed in the conductor housing 12 and includes wellhead bore 16 . Second intermediate casing hanger 32 is landed in the wellhead housing 14 and supports second intermediate casing string 42 . Hanger 32 is provided with annulus access port 36 , which allows for fluid communication between the wellhead bore 16 and the “C” annulus 50 after installation of hanger 32 . After the hanger 32 is landed in the wellhead housing 14 , pack-off 34 is installed between hanger 32 and the wellhead housing 14 , preventing further communication with access port 36 . [0006] First intermediate casing hanger 26 is then landed atop second intermediate casing hanger 32 and supports first intermediate casing string 40 . Hanger 26 is provided with annulus access port 30 , which allows for fluid communication between the wellhead bore 16 and the “B” annulus 48 after installation of hanger 26 . After the hanger 26 is landed on hanger 32 , pack-off 28 is installed between hanger 26 and the wellhead housing 14 , preventing further communication with access port 30 . [0007] Production casing hanger 20 is then landed atop first intermediate casing hanger 26 and supports production casing string 38 . Hanger 20 is provided with annulus access port 24 , which allows for fluid communication between the wellhead bore 16 and the production or “A” annulus 46 after installation of hanger 20 . The “A” annulus is located between the production casing string 38 and the production tubing, shown in phantom at 44 . After the hanger 20 is landed on hanger 26 , pack-off 22 is installed between hanger 20 and the wellhead housing 14 , preventing further communication with access port 24 . As is apparent from the figure, once all the casing hangers have been installed in the wellhead housing 14 , access to the “B” and “C” annuli is prevented. SUMMARY OF THE INVENTION [0008] In accordance with the present invention, these and other disadvantages in the prior art are overcome by providing a wellhead system which comprises a wellhead housing and a plurality of concentric casing strings, each of which is suspended from a corresponding casing hanger. The casing hanger for the radially outermost casing string is supported in said wellhead housing and the casing hanger for each successively smaller casing string is supported in the casing hanger for the next radially larger casing string. Each casing string defines a corresponding annulus which surrounds said casing string and is located below the casing hanger for said casing string. Furthermore, at least one casing hanger comprises a bypass port or similar means for providing fluid communication between the annulus below said casing hanger and an area above said casing hanger. [0009] Thus, the wellhead system of the present invention comprises a “stack-down” casing hanger configuration. In this type of system, the hanger for each successively smaller diameter casing string is landed or “nested” within the hanger for the next larger casing string. This approach allows the pack-off for each casing hanger to be retrieved independently, thus allowing fluid communication to be established with any of the casing annuli after all of the casing strings and hangers have been installed. Thus the pressure in each annulus may be monitored while the well is in production mode. [0010] These and other objects and advantages of the present invention will be made apparent from the following detailed description, with reference to the accompanying drawings. In the drawings, the same reference numbers are used to denote similar components in the various embodiments. BRIEF DESCRIPTION OF THE DRAWINGS [0011] [0011]FIG. 1 is a cross-sectional view of a prior art wellhead system having a stack-up casing hanger configuration. [0012] [0012]FIG. 2 is a cross-sectional view of the preferred embodiment subsea wellhead housing landed and locked in the stack-down wellhead, with the low-pressure drilling riser connected to the housing. [0013] [0013]FIG. 3 is a cross-sectional view of the preferred embodiment subsea wellhead system with the intermediate casing hanger landed and locked in the wellhead housing. [0014] [0014]FIG. 4 is a close-up cross-sectional view of the expandable load shoulder mechanism for the intermediate casing hanger. [0015] [0015]FIG. 5 is a cross-sectional view of the preferred embodiment subsea wellhead system with the production casing hanger landed and locked in the intermediate casing hanger. [0016] [0016]FIG. 6 is a close-up cross-sectional view of the expandable load shoulder mechanism for the production casing hanger. [0017] [0017]FIG. 7 is a cross-sectional view of the preferred embodiment subsea wellhead system with the casing hanger pack-offs retrieved. [0018] [0018]FIG. 8 is a cross-sectional view of the preferred embodiment subsea wellhead system with a horizontal Christmas tree connected to the top of the wellhead housing. [0019] [0019]FIG. 9 is a close-up cross-sectional view of the lower portion of the Christmas tree shown in FIG. 8. [0020] [0020]FIG. 10 is a cross-sectional view of an alternative embodiment surface drilled wellhead housing landed and locked in the stack-down wellhead, with the low-pressure drilling riser connected to the housing. [0021] [0021]FIG. 11 is a cross-sectional view of the alternative embodiment surface drilled wellhead system with the intermediate casing hanger landed and locked in the wellhead housing, and the high pressure drilling riser engaging the intermediate casing hanger. [0022] [0022]FIG. 12 is a cross-sectional view of the alternative embodiment surface drilled wellhead system with the production casing hanger landed and locked in the intermediate casing hanger. [0023] [0023]FIG. 13 is a cross-sectional view of the alternative embodiment surface drilled wellhead system with the production casing hanger pack-off retrieved. [0024] [0024]FIG. 14 is a cross-sectional view of the alternative embodiment surface drilled wellhead system with both casing hanger pack-offs retrieved. [0025] [0025]FIG. 15 is a cross-sectional view of the alternative embodiment surface drilled wellhead system with the external production tieback connector engaging the intermediate casing hanger. [0026] [0026]FIG. 16 is a cross-sectional view of the alternative embodiment surface drilled wellhead system with the internal production tieback connector engaging the production casing hanger. [0027] [0027]FIG. 17 is a close-up cross-sectional view of the internal production tieback connector engaging the production casing hanger. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0028] Referring to FIG. 2, the wellhead system of the present invention comprises a wellhead housing 54 which is landed in a stack-down wellhead 52 . The lower end of wellhead housing 54 is welded or otherwise rigidly attached to an outer casing 55 . Wellhead housing 54 is sealed and locked to stack-down wellhead 52 by a seal and lock assembly 60 . Wellhead housing 54 further comprises a wellhead bore 56 . A low pressure drilling riser connector 58 is locked and sealed to the upper end of wellhead housing 54 . [0029] Referring to FIG. 3, an intermediate casing hanger 62 is supported and locked within wellhead housing 54 by an expandable load shoulder 64 . Suspended from hanger 62 , via an adapter 70 , is an intermediate casing string 72 which cooperates with outer casing 55 to define a “C” annulus 74 . An annular space 67 is defined between hanger 62 and wellhead housing 54 . A pack-off 66 isolates space 67 from wellhead bore 56 . Intermediate casing hanger 62 further comprises a second expandable load shoulder 68 , the purpose of which is described below. [0030] Referring to FIG. 4, expandable load shoulder 64 comprises an internally toothed ring 80 , which resides in an internal groove 82 formed in wellhead housing 54 . Load shoulder 64 further comprises a drive ring 84 , an externally toothed ring 90 , and a stepped insert 92 , all of which are carried on intermediate casing hanger 62 . Before hanger 62 is landed in wellhead housing 54 , drive ring 84 and toothed ring 90 rest upon a support ring 86 . As hanger 62 is landed, an external shoulder 88 on drive ring 84 impinges on a lower shoulder 94 of groove 82 . As hanger 62 descends, drive ring 84 drives toothed ring 90 upward against stepped insert 92 . Toothed ring 90 is thus cammed outward into locking engagement with internally toothed ring 80 , and the weight of intermediate casing hanger 62 and intermediate casing string 72 are thus supported. Hanger 62 further comprises an annulus access port 76 which communicates with a groove 78 . Port 76 and groove 78 provide for fluid communication between annular space 67 and “C” annulus 74 , and thereby provide a fluid bypass around expandable load shoulder 64 . [0031] Referring to FIG. 5, a production casing hanger 96 is supported and locked within intermediate casing hanger 62 by expandable load shoulder 68 . Suspended from hanger 96 is a production casing string 102 , which cooperates with intermediate casing string 72 to define a “B” annulus 104 . An annular space 100 is defined between production casing hanger 96 and intermediate casing hanger 62 . A pack-off 98 isolates space 100 from wellhead bore 56 . [0032] Referring to FIG. 6, expandable load shoulder 68 comprises a retainer ring 108 , which is carried by intermediate casing hanger 62 and includes an internal lower lip 110 . Load shoulder 68 further comprises a lock ring 120 and an energizing mandrel 112 , which includes an external upper lip 114 . A locking mandrel 122 is threadedly connected to hanger 62 . Before production casing hanger 96 is landed in intermediate casing hanger 62 , energizing mandrel 112 is suspended from retainer ring 108 via engagement of lips 114 and 110 . Lock ring 120 , which is outwardly biased, is disposed below mandrel 112 . As production casing hanger 96 descends, an external shoulder 118 on hanger 96 impinges upon an internal shoulder 116 on energizing mandrel 112 . Lips 114 and 110 disengage, and mandrel 112 drives lock ring 120 downward. As lock ring 120 contacts locking mandrel 122 , lock ring 120 is cammed inward into a groove 126 in hanger 96 , and the weight of hanger 96 and production casing string 102 are thus supported. Adjacent to expandable load shoulder 68 , intermediate casing hanger 62 is provided with an internal slot 106 . Slot 106 provides for fluid communication between annular space 100 and the “B” annulus 104 , and thereby provides a fluid bypass around expandable load shoulder 68 . [0033] [0033]FIG. 7 shows the wellhead system of the present invention with both of the pack-offs retrieved in preparation for the production mode. Referring to FIG. 8, a subsea Christmas tree 128 is connected to the upper end of wellhead housing 54 via a connector 130 . A stab 136 extends from tree 128 into the wellhead housing 54 and engages intermediate casing hanger 62 . Christmas tree 128 further comprises a tree bore 138 and an annulus port 132 . When the production tubing and tubing hanger (not shown) are installed in the tree 128 , the annulus port 132 provides access to the production or “A” annulus between the production tubing and the production casing 102 . Thus the pressure in the production annulus may be monitored during production. [0034] Referring to FIG. 9, the pressure in the “B” annulus 104 may be monitored via a fluid path 166 . Path 166 comprises legs 146 and 148 in the tree 128 . Leg 146 exits the OD of tree 128 and may be connected to an external gage or other means for monitoring pressure. A leg 150 passes from the tree 128 into the stab 136 . A leg 152 continues longitudinally through stab 136 and intersects a leg 154 , which then passes into a lower section 140 of stab 136 . Leg 154 intersects a leg 156 , which continues longitudinally through lower section 140 and exits into a space 158 . Space 158 is defined below a seal assembly 142 , which seals between hanger 62 and lower portion 140 . Space 158 is in fluid communication with annular space 100 , which has already been shown to communicate with the “B” annulus 104 . Thus path 166 is in fluid communication with the “B” annulus 104 and can be used to monitor the pressure therein. [0035] Pressure in the “C” annulus 74 may be measured via a fluid path 168 . Path 168 comprises legs 160 and 162 in tree 128 . Leg 162 is in fluid communication with a space 164 which is defined between stab 136 and wellhead housing 54 . Space 164 , in turn, is in fluid communication with space 67 , which has already been shown to communicate with the “C” annulus 74 . Thus path 168 is in fluid communication with the “C” annulus 74 and can be used to monitor the pressure therein. [0036] Alternative Embodiments [0037] The present invention may also be utilized in a surface drilled well. Referring to FIG. 10, prior to completion the surface drilled system is essentially identical the subsea case (compare with FIG. 2). Referring to FIG. 11, an intermediate casing hanger 182 is landed in the wellhead housing 54 and locked therein via expandable load shoulder 64 , in a manner similar to the subsea case. A low pressure drilling riser 59 is attached to wellhead housing 54 via low pressure drilling riser tieback 58 . A high pressure drilling riser 172 is connected to hanger 182 via a high pressure drilling riser tieback 170 . An annular space 178 is defined between tieback 170 and wellhead housing 54 . An annular space 180 is defined between hanger 182 and wellhead housing 54 . A riser annulus 176 is defined between high pressure drilling riser 172 and low pressure drilling riser 59 . It should be understood that in the configuration shown in FIG. 11, annulus 176 is in fluid communication with both the tree at the surface and the “C” annulus 74 via space 180 . Thus the pressure in the “C” annulus 74 may be monitored from the surface. [0038] Referring to FIG. 12, a production casing hanger 184 is landed within intermediate casing hanger 182 and is locked therein via expandable load shoulder 68 . Pack-off 98 seals between hanger 182 and hanger 184 . FIG. 13 shows the wellhead system with pack-off 98 retrieved. FIG. 14 shows the wellhead system with both pack-offs retrieved and the low pressure drilling riser tieback disengaged. [0039] Referring to FIG. 15, an external production riser 188 is connected to wellhead housing 54 via an external production tieback connector 185 . An external production tieback 186 is attached to intermediate casing hanger 182 via a lock down nose 190 and is sealed thereto via a seal 196 . An annular space 192 is defined between wellhead housing 54 and tieback 186 . An annulus monitoring port 194 provides fluid communication between annular space 192 and the exterior of tieback 186 and may be connected to a gauge or other pressure monitoring means. [0040] Referring to FIG. 16, an internal production riser 198 is connected to external production tieback 186 via an internal production tieback connector 196 and a ratch-latch mechanism 202 . Connector 196 is sealed to production casing hanger 184 via a seal 204 . An annular space 200 is defined between internal production riser 198 and external production tieback 186 . It should be understood that in the configuration shown in a FIG. 16, annulus 200 is in fluid communication both with the tree at the surface and the “B” annulus 104 . [0041] Referring to FIG. 17, the communication path between annulus 200 and annulus 104 can be seen to bypass ratch-latch 202 and lock down nose 190 and continue on to the “B” annulus 104 in a manner similar to the subsea case. A communication path can also be traced between annulus 192 and the “C” annulus 74 via an annulus access port 206 in hanger 182 . Since annulus 192 communicates with monitor port 194 , the pressure in the “C” annulus 74 may be monitored during production. [0042] The embodiments here presented are at present considered to be the best modes for carrying out the invention. However, it should be understood that variations in the shape, number, and arrangement of the various elements may be made without parting from the true spirit and scope of the invention. Therefore, it is the applicant's intent to claim all such variations as fall within the scope of the invention.	A wellhead system for petroleum producing wells comprises a “stack-down” casing hanger configuration. In this stack-down system, the hanger for each successively smaller diameter casing string is landed or “nested” within the hanger for the next larger casing string. This approach allows the pack-off for each casing hanger to be retrieved independently, thus allowing fluid communication to be established with any of the casing annuli after all of the casing strings and hangers have been installed. Thus the pressure in each annulus may be monitored while the well is in production mode.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION The present invention relates to a new and unique variation of, and improvement over, conventional inverted roof structures. As a result of the practice of this invention, an inverted roof structure can be constructed which possesses superior fire-retardant, protective, and insulative properties, while concurrently significantly reducing the overall weight of the composite roof structure. It is an important feature of this invention that such improved structure can be constructed independent of the pitch angle the roof structure forms with the horizontal. The method and structure of inverted roof systems is well known and practiced by members of the building profession. For example, U.S. Pat. No. 3,411,256, held by the Dow Chemical Company, (hereinafter "Dow"), discloses an inverted roof structure, and method thereof, which comprises a roof deck, water impermeable membrane, closed cell water impermeable thermal insulating member, and a water permeable protective layer. This structure reduces exposure of the water impermeable membrane to adverse environmental conditions, thereby protecting the membrane and extending the useful life of the roof structure. While the structure taught by Dow is now used throughout the building industry, the structure possesses several significant limitations which renders it generally unsuitable for use under many naturally existing conditions. For example, inasmuch as the protective layer is water permeable, moisture passing therethrough ultimately contacts the underlying water impermeable membrane and can cause cracking of said membrane due to cyclical freezing and thawing conditions. Further Dow recognizes that the thermal insulation member is subject to decomposition, particularly when exposed to sunlight; however it fails to disclose a method by which the insulating member may be permanently protected from such elements. Still further, a roof structure constructed in accordance with the Dow disclosure utilizing styrene for the thermal insulation member requires approximately 1200 pounds of gravel per 100 square feet of roof surface area in order to receive an Underwriter's Laboratories Class R rating for fire retardancy. Finally, Dow fails to disclose a method by which the protective layer can be applied regardless of pitch angle, and, by necessity, structures constructed in accordance with the method of the invention are limited to low pitch angles. Therefore, it is an object of the present invention to provide a roof structure which substantially inhibits the absorption of water which may adversely effect the water impermeable membrane. Yet another object is to provide a protective layer which effectively inhibits deterioration of the underlying thermal insulation layer due to foot traffic and adverse environmental conditions. A still further object is to provide a roof structure which may be constructed without roof pitch angle limitations. And yet another object is to provide a roof structure characterized by superior insulative and fire retardant qualities while simultaneously achieving an overall reduction in the weight of the structure. SUMMARY OF THE INVENTION The present invention relates to a roof structure characterized by a thermal insulation layer secured to the exposed surface of a water impermeable roofing membrane. Adhesive material is thereafter applied to the exposed insulation layer surface and inorganic particles attached thereto in sufficient quantity to ensure that each particle contacts all other contiguous particles. The combination of adhesive and particulate forms what is known as a toothing surface, said surface serving as a means by which a final overlayment of inorganic mortar based compound may be secured to the roof structure. The final overlayment forms a protective skin which serves to retard water absorption through the roof structure, protect the substrate from injury due to foot traffic, ultra-violet light and adverse weather conditions, and increase the insulative "R" factor of the composite structure. It is a unique feature of the present invention that the incorporation of the toothing surface therein permits the application of the final overlayment at any roof pitch angle from horizontal. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the preferred embodiment illustrating the multiplicity of layers and materials which comprise my inverted roof system. DESCRIPTION OF THE PREFERRED EMBODIMENT For a more complete understanding of my invention, reference may be made to FIG. 1 which illustrates an inverted roof system 10 constructed in accordance with the practice of the present disclosure. The inverted roof system 10 comprises a roof deck 11 secured upon a multiplicity of rafters or other suitable roof support structure (not shown), said roof deck 11 having an exposed outer surface 12. A water impermeable membrane, comprising a plurality of alternating layers of adhesive 13, roofing felt 14, and a final overlayment of adhesive-sealant coat 13A is thereafter secured to the roof deck 11 such that the exposed outer surface 12 of roof deck 11 is completely covered by the water impermeable membrane. Secured upon adhesive-sealant coat 13A, the outermost layer of the membrane, is a thermal insulation layer 15 having an upper surface 16. A toothing surface is formed upon the thermal insulation layer 15 by coating the upper surface 16 of layer 15 with an adhesive 17, and thereafter partially imbedding a singular layer of inorganic particles 18 into adhesive 17. The particles 18 are applied in sufficient quantity so as to ensure that the entire exposed surface of adhesive 17 is uniformly covered with the particles 18, each particle in continuous contact with contiguous particles. Finally, a mortar based insulative-protective layer 19 is applied onto the toothing surface, thereby completing the composite structure. If aesthetically desired, additional particles 18 may be partially imbedded into layer 19 prior to its solidification. The roof support structure, the roof deck, water impermeable membrane, and thermal insulation layer may be constructed from a wide variety of materials well known to practitioners in the building industry. For example, the water impermeable membrane may be fashioned by overlapping alternating layers of asphaltic base adhesive and roofing felt in sufficient quantity to ensure water impermeable integrity, two or three layers of each usually considered as being satisfactory. Selection of the proper sealant-adhesive coat to be overlayed upon the water impermeable membrane depends upon the practitioner's choice of material used to form the thermal insulation layer. Beneficially, such insulation layer would be comprised of closed cell plastic foam material such as polyurethane foams, styrene polymer foams, and others well known to the art. Inasmuch as polyurethane foams and the like are characterized by a high degree of resistance to degredation and distortion when contacted with high temperature adhesive materials such as hot asphalt, either hot process or cold process adhesives may be utilized to seal the membrane and secure the thermal insulation layer thereon. Styrene, however, is particularly susceptible to distortion and degredation when contacted with high temperature adhesive materials; therefore, the use of a cold process, water based acrylic resin or asphaltic emulsion for the sealant-adhesive coat is desirable in order to secure the styrene material upon the underlying substrate. Adhesives such as those manufactured by Thermo Materials, Incorporated of San Diego, Calif. under the names Thermo Concentrate #101A (thermo plastic acrylic polymer) and Thermo Series 200 E (asphaltic emulsion) have proven suitable for use in bonding the styrene to the membrane. These aforementioned limitations similarly apply to the selection of the adhesive incorporated into the toothing surface. If styrene, or other similar thermo plastic synthetic resinous material is used to form the thermal insulation layer, the adhesive must be ameanable to cold process application. Alternatively, hot asphalt may be utilized as an adhesive if interposed between the styrene and the adhesive is a protective layer of saturated asphaltic felts or the like which serve to inhibit styrene degredation. While the adhesive utilized in the toothing surface is in a plastified state, +1/4 inch, -3/8 inch gravel, applied at the rate of approximately 150 pounds gravel per 100 square feet of adhesive surface area, is partially imbedded therein in sufficient quantity to ensure contiguous particle contact over the entire adhesive surface. Where the possibility of water ponding and continuous cyclical freeze/thaw conditions are likely to occur, gravel size must be increased to +1/4 inch, -3/8 inch. When the roof structure has been thus far completed, the final construction step consists of the preparation and application of the insulative-protective layer. Basically, the layer is comprised of an inorganic mortar based compound made up of the following ingredients in substantially the proportions stated: ______________________________________White cement 51%Magnesium silica or calcium carbonate flour 38.5%Perlite fines; +200, -300 mesh 1.5%Clay; +200, -300 mesh 3.0%Lime; +200, -300 mesh 5.5%Thickener 0.2%______________________________________ The above mixture of dry powder is thereafter added in a continuous stream at the rate of 50 pounds powder to six gallons of water and agitated to ensure homogenity. Finally, an additional one-half gallon of vinyl acrylic polymer or acrylic emulsion vehicle is added and uniformly dispersed throughout the mixture prior to ceasing agitation. The latter ingredient serves the purpose of increasing the compressive strength of the protective-insulative layer, and retards water absorption through the layer. The ingredients disclosed in the above example will yield a white color composition. It should be understood, however, that color variation may be obtained by the addition of pigments or the like. Still further, the above example contemplates application of the mixture under moderate temperature conditions. If application is to be made at temperatures below freezing, five pounds of barium chloride per 50 pounds of dry powder may be added to accelerate prolonged setting associated with low temperature conditions. The composition thus formed is thereafter uniformly applied with a pressure hose upon the entire toothing surface at a minimum rate of 50 pounds per 100 square feet of surface area. During application, the composition remaining to be used must undergo continuous agitation and any of the mixture not utilized within three hours of mixing must be discarded. It is thus seen that upon solidification of the insulative-protective layer, a structure is formed possessing superior insulative, protective, and fire-retardant qualities over present state of the art structures. Further, by incorporating a toothing surface into the composite structure, a surface is formed whereby the insulative-protective layer may be secured to the roof structure without restriction due to the roof pitch angle. It is understood that the above description of my invention is done to fully comply with the requirements of 35 USC 112 and not intended to limit my invention in any way. It can be seen that variant forms of my invention could easily be developed by practitioners skilled in the art. For example, the toothing surface could be eliminated from the composite structure whenever the roof pitch angle is substantially 0°. Inasmuch as this and many other variant forms of my invention are possible, such variant forms are considered to be within the scope and essence of my invention.	A roof structure wherein a water impermeable membrane is fabricated upon a roof deck and a thermal insulation layer affixed upon the membrane. The insulation layer is thereafter coated with a suitable adhesive material and particles of inorganic particulate attached thereto, whereby a toothing surface is formed upon which is applied a mortar based insulative-protective layer.
You are an expert at summarizing long articles. Proceed to summarize the following text: SPECIFICATION Field of the Invention This is a continuation application of United Kingdom application 9913567.5 filed in the U.K., Jun. 11, 1999, now pending. Priority is claimed to PCT application No. GB 99/04097 filed Dec. 10, 1999. This invention relates generally to handling of waste materials especially particulate solids. A method of transferring such materials from one location to another, and an apparatus suitable for performing the method, is described hereinafter. The invention finds particular utility in the oil and gas industry for disposal of well or drill cuttings (“hereinafter cuttings”) discharged from the solids control system on a well drilling site. BACKGROUND OF THE INVENTION Cuttings are typically pieces of rock, which have been chipped, ground or scraped out of a formation by a drill bit. Various types of drill cutting tools_are in use for this purpose and the invention hereinafter described is not limited to use of any particular type. The drilling operation is conducted several hundred meters below the operation control point, which means that performance of the drill bit is critical to the operation. The effectiveness of the drill bit during a drilling operation relies upon the continual removal of cuttings; otherwise the drill would rapidly foul up due to accumulation of cuttings. Therefore, the cuttings are normally removed by delivery of a drilling fluid (often referred to as “drilling mud”) down to and around the drill bit in a recirculated manner by use of the drill string and annulus casing well established in the industry. Accordingly the cuttings are commonly separated from the drilling fluid by devices such as a shale shaker, which captures cuttings and large solids from the drilling fluid during the circulation thereof. Basically, such a device has a sloping, close mesh, screen over which fluid returning from the hole being drilled passes. The screen may be typically of from 200×200 down to 30×30 mesh and is vibrated to facilitate separation of the majority of fluids from the solids. The solids captured on the screen travel down the sloping surface to be collected in the shaker ditch or cuttings trough. It is also desirable to recover as much of the expensive drilling fluids as possible. Therefore, other devices, which play a role in the separation of solids from drilling fluids, include cyclone separators, and centrifuges. The cuttings discharged from the shakers, cyclone's and centrifuges that are collected in the shaker ditch or cuttings trough are still highly contaminated with the drilling fluids and therefore form a slurry or heavy sludge. The slurry or sludge is very difficult to move or otherwise transfer in any conventional manner. In some cases the cuttings slurry may be discharged directly into a cuttings box where space permits or vacuum collected, which under current practice means that the cuttings are sucked from the cuttings ditch or trough, by an applied vacuum, directly into a cuttings box for transport to an approved disposal site for re-claimation suggested in GB-A-2 286 615. However, in some cases in order to facilitate removal of the cuttings, a collection hopper may be used which allows a particular ground clearance typically of about 4 meters whereby the cuttings are discharged from the hopper by free-fall into open cuttings containers. It is also proposed there to include another trough for intermediate collection of cuttings. A screw conveyor for lateral displacement of cuttings from beneath the intermediate trough is described. The screw conveyor pushes the cuttings, which fall into it from the trough towards a discharge trap door that opens under the weight of the cuttings to periodically allow the cuttings to fall into the holding tank. The intermediate trough described remains under the influence of the suction pump to continue delivery of recovered fluid to a recycle system, whilst the screw conveyor below the trough shifts cuttings towards the trap door. In a more recent operational system a vacuum cuttings hopper is provided including, a helical screw therein on a vertically arranged shaft driven by an overhead motor assists the delivery of the solids to the free-fall outlet for collection below the hopper, The cuttings are further subjected to compression by the helical screw prior to discharge thus extracting and recovering a substantial amount of the remaining fluids in the slurry. The extracted fluid is then withdrawn through a perforated casing around the screw under the action of a pump. The problems associated with cuttings handling for disposal are familiar to all workers on a drilling installation and include the need for the presence of several storage containers to handle the volumes of cuttings produced and the time demands upon the installation's crane devoted to the shifting of a filled container to substitute an empty container close to the shaker station. This container “shuttling” routine is not only absorbing useful operational time for the crane but also presents additional physical hazards to workers involved in other tasks in close proximity to the cuttings containers. Furthermore, the cuttings recovery equipment and the containers themselves are usually accessed by workers scaling ladders, or scaffolding or the like staging up to heights often approaching 5 or 6 meters or thereabouts in order to open container lids or service the cuttings handling equipment. Of necessity the containers themselves must be sited close to the cuttings shaker station and be accessible by the crane. These factors have an impact on use of deck space, personnel mobility, and other task completion operations around the deck. Further the filling and relocation of cuttings containers is dictated by the volume of cuttings being produced by the drilling operation in any given period of time. Therefore, it is essential that the cuttings handling apparatus and its methods of operation be capable of handling the volumes required to maintain production. An object of the present invention is to provide improvements in cuttings handling for disposal and recovery of reusable drilling fluids and muds from the drill cuttings slurry thereby reducing cost of disposal and recycling. A object fulfilled by aspects of the invention to be described hereinafter is to provide a drill cuttings recovery system of more compact or efficient design. A still further object is to provide a more flexible disposal method allowing the operator greater degree of freedom in the options for handling the cuttings prior to disposal. Generally the invention seeks to provide a system and method for handling of cuttings, which offers an improved alternative to current handling systems. The invention, according to a first aspect, provides a method for handling cuttings that includes providing a system utilizing a screw pump to remove the cuttings from the cuttings trough and disperse them through a piping system to various disposal points. The invention according to another aspect, provides a method for handling of cuttings, which method comprises providing a vessel adapted to sustain a reduced internal pressure with respect to external ambient atmospheric pressure, and external pumping means, said vessel and pumping means being operationally connected by means including a conduit, collecting cuttings from a drilling fluid/cuttings separation device in said vessel, removing cuttings from said vessel by means of said pumping means through said conduit whilst maintaining a reduced pressure, and selectively delivering removed cuttings by means of pumping to at least one of a variety of disposal points including a cuttings re-injection apparatus, removable transportable cuttings containers including a barge or the like for shipping to a remote disposal site. According to another aspect of the invention there is provided an apparatus for handling of cuttings, comprising a vessel adapted to sustain a reduced internal pressure with respect to external ambient atmospheric pressure, and further provide a means for extracting fluids, the apparatus also having operationally connected thereto, external pumping means capable of maintaining the reduced internal pressure and removing the separated fluids while discharging the cuttings to a variety of storage containers or to a cuttings re-injection apparatus. In accordance with still another aspect of the invention a centrifugal dryer is provided for drying the drill cuttings prior to distribution, by way of a blowers and or vacuum systems, to various holding containers located on or near the rig. This drying process removes the fluids and thereby allows all of the cuttings being produced by the drilling operation to be contained on the rig for longer periods of time prior to removal or re-injection. Significantly, according to the invention, the proposed use of the pumping means for not only initially collecting the cuttings under vacuum, but also removing cuttings under reduced pressure or “vacuum” conditions, and utilizing the pumping means to selectively convey the cuttings onwards via dedicated conduits to a cuttings storage container, or directly into a cuttings re-injection facility, offers several significant advantages. Firstly, the demands on the crane are reduced because the cuttings containers do not need to be continually cycled around for filling and emptying operations. The containers can be stowed or sited in convenient locations without taking account of the shaker station position other than to ensure that suitable vacuum conduit lines are available or provided to feed the cuttings directly into the containers. The crane then becomes essentially free to fulfill other essential tasks such as handling drill pipe etc. The freedom to locate containers anywhere that a cuttings vacuum transport line can be installed and accessed immediately also provides greater freedom on the deck for operator movement, and greater flexibility in utilization of deck space around the shaker station and elsewhere. Secondly it offers the possibility of directly off-loading cuttings to a barge or bulk transport ship standing on station close to the drilling facility. Thirdly, health and safety aspects are enhanced due to reduced contact between workers and the cuttings, who need longer clamber over the cuttings containers to access them thereby reducing contamination hazards and risks of personal injury by falls. The conduit network may be a fixed installation or arranged so as to permit re-deployment of a selected or each conduit at will. The conduits are designed sufficiently to permit transfer of the particulate solids constituting the cuttings and avoid blockages, and pump overloading but are also sized to avoid loss of vacuum transfer velocity. It will be understood that the pumping means referred to herein in relation to the various aspects of the invention may consist of one or more pumps having the necessary functions of generating a pressure differential to move cuttings in the desired way and combinations of pumps can be adopted. Preferably, the pumping means comprises, at least, (i) gas pumping means e.g. a vacuum generating unit capable of creating the desired pressure reduction in the vessel and (ii) a solids displacement means, which may be one of several types suitable to the purpose, including positive displacement pumps, e.g. a piston pump, or paddle devices e.g. using rubber paddles, or a progressive cavity pump capable of continuous displacement of solids, preferably at about 25 tons per hour or more. Advantageously, location of the pumping means external to the vessel is such that solids displacement is so primarily lateral rather than vertical as required for the known solids free-fall under gravity system, which reduces height requirements The vessel can then be installed at ground (deck) level with no height elevation requirements which improves safety for operatives. In this way equipment provided in accordance with the invention can exhibit a relatively low profile compared with prior art systems and is more easily installed and maintained by operatives with less risk of injury due to falls. Furthermore in contrast with the prior art operational system described above where the vertically arranged helical screw is within the cuttings hopper itself, the pressure vessel arrangement described herein is less complicated in structure and provides for easier care and maintenance operations. Overall, the system proposed herein results in more efficient use of space in the installation, and reduces hazards associated with earlier systems. The vessel and pumping means described herein are operationally connected so as to maintain a reduced pressure or vacuum within the system, which may be achievable by fastening arrangements satisfying usual industry pressure vessel standards, including flanged connections and dedicated hard conduits of adequate strength. The reduced pressure can be maintained by a suitable type pump known in the industry or custom built for this system. It will be understood that primarily the invention addresses solids handling, and the precise nature of the vacuum unit or gas pump is not critical. The arrangement of the invention is such that the pumped cuttings can either be directed from the reduced pressure vessel into appropriate storage facilities such as containers or directly into a cuttings re-injection device enabling the cuttings to be returned to the drilled formation. Furthermore the cuttings can be “piped” off the installation into a barge or similar bulk cargo transporter. Cuttings re-injection under high pressure back into an earth formation is described in principle in the following U.S. Pat. Nos. 4,942,929, 5,129,409, and 5,109,933, and treatment of drill cuttings is discussed in the following U.S. Pat. Nos. 4,595,422, 5,129,468, 5,361,998 and 5,303,786. However, these early proposals have not been easy to implement in the field for those lacking the appropriate skill and understanding, and this has resulted in cuttings re-injection not gaining wide acceptance amongst operators, especially in offshore drilling installations in the North Sea. The present invention arises from developments following on from proven re-injection techniques successfully employed by APOLLO Inc. in offshore drilling operations. DESCRIPTION OF THE DRAWINGS The invention will now be further described with reference to the accompanying drawings in which: FIG. 1 is a plumbing illustration arrangement for the preferred embodiment of the materials handling system; FIG. 2 is a plumbing illustration arrangement for an alternate embodiment of the preferred system; FIG. 3 is a plumbing illustration arrangement for an alternate vacuum system; FIG. 4 is a plumbing arrangement and an optional discharge receptacle for the system shown in FIG. 3 system; FIG. 5 is a plumbing arrangement and an optional discharge receptacle for the system shown in FIG. 3 system; FIG. 6 is a cutaway side elevation of a low profile reduced pressure vessel and associated pumping means in accordance with the invention; FIG. 7 is side elevation of a low profile reduced pressure vessel and associated pumping means in accordance with the invention: FIG. 8 is a plumbing arrangement for the system shown in FIG. 2 adding an optional surge tank. FIG. 9 is a plumbing arrangement for the system shown in FIG. 1 with addition of an optional surge tank and pump combination; FIG. 10 is a plumbing arrangement for the system shown in FIG. 5 with separator discharging into a surge tank. FIG. 11 is a top view of the surge tank; FIG. 12 is a cross section view of the surge tank; FIG. 13 is a plumbing arrangement for the system first shown in shown in FIG. 8 substituting a centrifugal dryer for the surge tank; FIG. 14 is a second embodiment of the plumbing arrangement for the system shown in FIG. 13; FIG. 15 is a third embodiment of the plumbing arrangement for the system shown in FIG. 13; and FIG. 16 is a fourth embodiment of the plumbing arrangement for the system shown in FIG. 13 . DETAILED DESCRIPTION As shown in FIG. 1, the preferred embodiment of the invention is a system by which cuttings leaving the shaker 10 may be collected from the cuttings trough 12 by gravity feed into a progressive cavity or fixed displacement piston type solids pump 14 and then pumped through a system, of conduits selectively to one or more of the possible discharge ports or disposal points located around the drilling site or platform. Such disposal points or discharge ports may be selected by opening valves 16 as needed to dispense the cuttings to a cuttings/fluid separator 18 , a barge 20 a cuttings box 22 or other transport means such as a truck 24 for further disposition. Defluidized cuttings discharged from the separator 18 may be collected in various containers such as a cuttings box 22 seen in FIG. 3, a truck 24 as seen in FIG. 5 or into a slurry processing unit 26 for injection into the earth formation around the well as also seen in FIG. 1 . By adding a vacuum pump unit 28 and vacuum chamber 30 as seen in FIG. 2 to the solids pump 14 and its associated system shown in FIG. 1 the system is then capable of extracting the cuttings from the cuttings trough by vacuuming them directly into the chamber 30 which serves as a hopper for feeding the cuttings to the solids pump 14 . As discussed herein this arrangement is useful when space under the cutting trough is insufficient to accommodate the solids pump 14 . Since the cuttings are still in slurry they can be pumped to the various discharge points. However, once the fluids have been extracted by the separator 18 it is much more difficult to move the materials without adding more fluid. Therefore, the defluidized cuttings are discharged from the separator 18 directly to the containers 22 , 24 or to the injection processing unit 26 as disclosed in FIGS. 3-5. Turning now to FIG. 3 we see that the previously known fluid separator 18 may also be used as the vacuum chamber for extracting the cuttings directly from the cuttings trough 12 . However, the separator has the distinct advantage of being capable of efficiently removing and reclaiming most of the remaining fluids from the cuttings thereby reducing the weight and volume of the cuttings to be transported. As shown in FIG. 6, the previously known operational fluid separator system 18 collects cuttings 15 from the cuttings trough 12 that collects solids falling via gravity from inlet suction line 32 as a result of the separator having a reduced internal pressure created by the gas suction pump system 28 seen in FIG. 2 attached to the separator by line 34 . The separator 18 is generally diametrical in shape having cylindrical side walls 35 and a top 40 with a sloping mid portion 110 and a smaller cylindrical lower portion 52 culminating at an open discharge port 85 . The interior is divided into an upper chamber 38 bound by side wall 35 , top 40 and inclined partition 45 , a mid chamber 105 bound by the inclined partition 45 sloping side wall 110 and partition 56 and a lower chamber 58 within the smaller cylindrical lower portion 52 serving as the housing for an adjustable valve assembly 75 . The upper chamber communicates with the mid and lower chambers 105 , 58 with screen assembly 50 . Positioned substantially central along the vertical axis of the screen member 55 is a shaft 60 , which supports a screw conveyor driven by a motor drive 90 . The screw flight portion 65 extending from the upper chamber through the screen assembly 50 and culminating at the screen discharge end portion 70 which is substantially blocked by valve assembly 75 . Cutting being conveyed from the upper chamber 38 to the discharge port 70 must force the valve open to allow the cuttings to 15 to communicates with lower chamber 58 and be discharged through the discharge chute 80 . Chute 80 empties into opening 85 which disposes cuttings into a container as seen in FIGS. 3-5. The side walls 35 , inclined walls 45 , and screen assembly 50 communicate and form a seal with the screw flighting 65 and the mid chamber 105 so that when a vacuum is applied using suction line 34 , cuttings can be suctioned from trough 12 to the upper chamber 38 of the separator and then conveyed through the screen assembly 50 to wards the closed valve assembly 75 thereby compressing the cuttings 15 and forcing fluids and solids less than 20 micron through the screen 55 and apertures in screen sleeve member 100 . Fluids accumulated in the mid chamber 105 are then drawn off by pump 115 to be a fluids recovery container 120 via discharge line 95 . The remaining solids are disposed of via discharge valve assembly 75 and travel down the discharge chute 80 under gravity and are emptied into containers via the opening 85 where they await disposal or re-injection. The reduced pressure vessel 30 first illustrated in FIG. 2 and further detailed in FIG. 7, illustrating this aspect of the invention, there is shown a relatively low profile reduced pressure vessel 205 and associated pumping means 210 in accordance with the present invention. The apparatus 200 for handling of cuttings comprises a vessel 205 adapted to sustain a reduced internal pressure with respect to external ambient atmospheric pressure, and operationally connected thereto, external pumping means 210 capable of both operations of maintaining the reduced internal pressure and removing cuttings from the vessel 205 , and means including a conduit 215 for selectively delivering cuttings to either a storage facility or to a cuttings re-injection apparatus. (not shown) The illustrated vessel 205 has four generally rectangular sides 225 , which communicate with an opening 230 via inclined walls 255 and a delivery chute 240 . The vessel 205 also has a rectangular top cover 245 . The vessel 205 is supported by a framework 250 to which it is attached, e.g. by welds. However, it will be appreciated that other shapes of sealed pressure vessel can be adapted in the invention. The system described here is designed to fully satisfy current industry pressure vessel standards. The pumping means 210 illustrated comprises a progressive cavity pump 220 capable of continuous displacement of solids, here at about 25 tons per hour or more. Other positive displacement pumps may also be used, Location of the pumping means 210 external to the vessel 205 is such that solids displacement is primarily lateral rather than vertical as required for the known solids free-fall under gravity system which provides for low height requirements. The vessel 205 is installed at ground level with no height elevation requirements. In this way the equipment has a low profile and is more easily installed and maintained with less risk to maintenance technicians or other operatives of falling. Furthermore in contrast with the prior art operational system described above where the vertically arranged helical screw is within the vessel itself, the arrangement described herein is less complicated in structure and provides for easier care and maintenance operations. The vessel 205 and pumping means 210 described herein are operationally connected so as to maintain a reduced pressure be low atmosphere or vacuum within the system, which may be achievable by fastening arrangements satisfying usual pressure vessel standards, including flanged connections 240 and dedicated hard conduits of adequate strength. The reduced pressure can be maintained by a vacuum pump of any suitable type, and although illustrated here as having both gas and solids pumping means together, the gas (vacuum) pump could be remote from the solids pump. The arrangement of the invention is such that the pumped cuttings can either be directed from the reduced pressure vessel 205 into appropriate storage containers or directly back into a cuttings re-injection device as a matter of operator's choice, as is apparent from the flow illustration seen in FIGS. 1 and 2. As seen in FIG. 8 the cuttings handling system may also be configured to include a surge or holding tank 300 whereby the cuttings slurry being discharged from the pump 14 is received and held for selective redistribution and pumping to the various containers and systems around the drill site. This surge tank 300 may be necessary to insure that the system does not become constipated and back up as result an inability to discharge the cuttings freely to a container. As seen in FIG. 9 the surge tank 300 which includes an integral progressive cavity pump 310 may also be used as the prime pump system whereby the cuttings are received directly from the shaker screens 10 or from the shaker trough 12 by gravity feed. The cuttings are then agitated and maintained in solution until pumped down stream to the site containers or other systems. As seen in FIG. 10 it is also possible to locate the surge tank 300 in position to receive cuttings directly from the cuttings fluid separator 18 . In this case the cuttings have been striped of their valuable drilling fluids and recovered. Therefore, the cutting may be discharged into the surge tank where water or other environmentally adaptable fluids are added through conduit 312 , which help prepare the cuttings for earth reclamation prior to discharge to the cuttings container and systems. As seen in FIGS. 11 and 12 the surge tank 300 includes a rectangular vessel having a bottom 314 and side and end walls 318 , 316 . A progressive cavity or other such large volume positive displacement type pump is integrated into one end wall as best seen in FIG. 12. A partition 320 having a central gate portion 322 with removable portions 324 to allow for control of fluid/sediment levels within the vessel. An agitation system 326 is also provided which is trackable on wheels along rails attached to the upper sides of the tank walls 318 . The agitator includes a bridge 328 supported by wheel assemblies. A drive 332 is also provided for moving the bridge 328 from one end of the tank to the other. A pair of telescopic cylinders 334 is provided for extending and retracting a centralizing screw conveyor auger 336 . The auger serves to move the cuttings toward the center of the tank and help maintain them in solution so that they will flow over the partition gate 322 . In off-shore drilling, it is essential that digestion and disposal of the drill cuttings flowing from the well at inconsistent flow rates be processed and disposed of in a manner that prevents constipation of the drilling operation. Therefore, the more alternatives available for cuttings disposal and fluid recovery on a drilling rig the better. In keeping with this principle alternatively, a centrifugal dryer 400 may be adapted to the systems as previously illustrated in FIGS. 1 and 2 in the manner illustrated in FIGS. 13 and 14. As seen in FIG. 13 cuttings are transferred to the vacumn receiving tank and pump assembly 30 through suction line 32 from the cuttings trough 12 in the same manne as in FIG. 12 . The cuttings are then transferred from the vacuum chamber 30 with the pump 14 and deposited into the inlet 402 of the centrifugal dryer 400 where the cuttings are spun at high speed forcing the fluids from the slurry out though the fluid ejection tube 404 . The relatively dry cuttings, typically below 3% fluid by weight, are then deposited into a receiving bin 403 capable of storing large quantities of the dried cuttings before being discharged by way of the transfer conveyor 406 . The transfer conveyer may also contain a metering feeder 408 with internal seals to prevent back flow of the dried cuttings, prior to feeding the cuttings into the transfer line 500 . The transfer line 500 may be charged with an additional blower 28 a such as that used in assembly 28 previously disclosed herein. A venturi located within jet pump 502 may be used to help draw the dry cuttings into the charged discharge line 500 . Dry cuttings are then directed to any of several optional outlets leading to receiving units 20 - 26 by opening and closing valves 16 . Cyclone separators 504 are located at each of the receiving units for separating and exhausting the pressurized air prior to discharge into the receiving units. Exhausted air may be discharged to atmosphere through exhaust/filter units to remove fine cuttings particles. As seen in FIG. 13 dried cuttings may be transferred directly from the transfer conveyor 406 to transfer lines leading to the optional outlets 20 - 26 . In this case a second vacuum pump 28 is collectively connected to the discharge of each cyclone separator 504 located at each of the optional distribution outlets 20 - 26 thereby drawing the cuttings through the distribution lines. In this case any airborne fines are collect in the filter receiver 510 located inline ahead of the vacuum pump 512 . As seen in FIG. 14 a primary and secondary means of fluid separation and recover may be used whereby the fluid separator unit 18 is utilized as the vacuum chamber for vacuuming the cuttings from the cuttings trough regardless of whether or not the cuttings compression feature of the separator is utilized or not. However, if the cuttings compression and fluidseperation feature is utilized the cuttings will enter the inlet of the centrifical dryer unit 400 with less moisture content, thereby insuring a more through recover of drilling fluids and muds and dryer cuttings being fed to the cuttings transfer system. It is also anticipated that cuttings may be collected from any number of cuttings troughs 12 and conveyed by a screw conveyer 405 to the inlet of the centrifugal dryer unit 400 as seen in FIG. 16 . In either case the systems shown in FIGS. 15 and 16 reduce cuttings bulk and transport weight and further recover expensive drilling fluids. The cuttings handling systems proposed herein offers remarkably higher levels of safety due to the reduced number of handling operations such as interventions by operatives to hook up containers to the crane, transfers of containers around the shaker station, etc. Furthermore, the sealed vacuum pressure vessel and associated network of vacuum conduits provides for delivery of cuttings to a container, re-injection equipment or transport for shipping to a remote disposal site, thereby preventing the possibility of constipation due to high production of drill cuttings at any given time. The full significance of the capabilities of the system proposed here, and variants thereof will be apparent to those appropriately skilled in this art and who will recognize that the scope of the invention is not limited to the illustrative embodiment specifically described above.	An apparatus and method for removing and recovering up to 98 percent of the residual drilling mud and fluids from drill cuttings for reuse and storing the drill cuttings in a relatively dry state thereby reducing cuttings volume requirements for storage and transport thereby reducing constipation of the drilling process due to disposal congestion. The present invention further provides methods for collecting and transferring drill cuttings in either dry or wet states to various locations on or adjacent the rig for processing, containerization, transport and disposal, thereby reducing handling and contamination thus simplifying recycling while reducing cost.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION Field of the Invention This invention relates to panic exit devices having one or more vertically operating bolts at the top and/or bottom of the door. An example of such a device wherein the bolts may be retracted solely by means of a key operated lock which also services to lock the bolts in the retracted position or by depressing a panic bar, is described in the U.S. Patent to T. Bejarano, U.S. Pat. No. 3,334,500. Other examples of such a device are disclosed in the U.S. Patent to Schmidt, U.S. Pat. No. 3,993,335 and Hubbard et al, U.S. Pat. No. 4,225,163. There are numerous types and styles of mechanisms used for operating the popular commercial and industrial door latch where the bolts reciprocate vertically and extend from the top and bottom of the door. Most of these mechanisms include or are adapted to include a panic bar release arrangement on the inside of the door for rapid and foolproof actuating of the bolts by merely depressing the panic bar to open the door. Many such mechanisms include an often desirable feature of permitting manipulation of a device to latch the bolts in a retracted position during business hours or the like, whereby the door is free to swing open without operating the panic bar or hitting any other release mechanism. This is known in the industry as a "dogging" feature and is usually accomplished by flipping a lever or threading a screw into a position to block the operating mechanism in the depressed position of the panic bar or other release mechanism. Often, it is particularly desirable that this dogged condition of the door not be inadvertantly or maliciously released and therefore, a special tool or unique knowledge might be required to set and release the dogging mechanism. For example, a recessed screw has been used as the actuating means for the dogging mechanism whereby a screwdriver and considerable effort are needed for actuation, but this has the inherent objectionable feature of requiring a substantial amount of the authorized operator's time to actuate the dogging mechanism. Another now-conventional arrangement as shown in the aforementioned U.S. Pat. No. 3,334,500 provides a pivotable stud having a relieved shank portion adapted to engage a portion of the bolt retraction mechanism so as to reach a dogged condition with a 1/2 turn rotation of the stud. Although this dogging arrangement is an improvement over other methods, it results in the tension being removed from the panic bar handle, leaving it in a flopable condition. In U.S. Pat. No. 3,993,335 a dogging arrangement is disclosed wherein a recessed pin is elevated and rotated to move the actuator bar into an actuated position while simultaneously restraining the panic bar from returning to the inactive position. Another feature that is often required with this type of bolt mechanism is the provision of a keyed exterior lock to permit opening of the door from the outside. Conventionally, these mechanisms are provided with an exterior lever or knob which is released by the operation of the keyed lock and then may be manipulated to retract the bolts for opening the door. Alternatively, the keyed lock may operate a separate bolt which must be released before the door may be opened by the operation of the knob or lever. U.S. Pat. No. 3,334,500 provides a vertical bolt operating mechanism capable of actuation by an exterior keyed lock, wherein the bolts may be latched in their retracted position by appropriate manipulation of the keyed lock in conjunction with manipulation of an interiorly facing operating means, and that arrangement is particularly suitable for and compatible with the present invention. Still another desirable feature in many installations of this type of bolt mechanism is to minimize the size of both the door stile containing the bolts and the mechanism for operating the bolts. This is particularly desirable with glass doors which derive their esthetic quality from their uncluttered look. The particular locking mechanism disclosed by Bejarano allows such a narrow door stile. Additionally, it is desirable to provide an exit device which may be easily and economically mounted on the door stile, regardless of whether the bolt mechanism is on the left hand or right hand stile. To provide smooth operation of installations of this type, some form of bolt latching mechanism is usually provided which retains the bolts in the retracted position when the interior or exterior actuating device is operated during the time the door is open. This prevents the need to continue pressure on the panic bar or key in order to prevent the bolt from contacting the ground while the door is swinging open and closed. The bolt latching mechanism is usually designed to trip and release the bolt when the door reaches the closed position. U.S. Pat. No. 3,334,500 shows such a latching mechanism. However, latching mechanisms of this type have proved unsatisfactory, since the bolt which is screwed on the connecting shaft must be rotated a full 360° in order to vary the portion of the bolt which extends above and below the door. This often results in situations where one turn more is too much, but the present length is not enough. U.S. Pat. No. 3,993,335 discloses an arrangement for providing the bolt latching means and hexagonal locking bolts within a conventional retraction mechanism so that the distance the bolts protrude above or below the door stile may be adjusted with precision. SUMMARY OF THE INVENTION The invention provides for the mounting of a novel actuator device on the internal side of the door causing the vertical movement of the projecting actuating pin of a particular type of conventional retraction mechanism for vertically operating bolts which retracts the bolts. The actuator device comprises an active unit assembly mounted in a semi-hollow enclosure which is integral with the door, and engages the actuating pin in the active stile. The actuator device is mounted with screws hidden by the glass pane securing mouldings. The bolt retraction mechanism is mounted in a fixed position in the interior of the active stile with screws hidden by the glass pane and glass pane securing mouldings. Another object is to provide a novel linkage arrangement between the manually depressible panic bar and the actuating pin engaging arm to translate horizontal movement of the bar into vertical movement of the pin. An object of the invention is to provide a panic exit device which has a flush mounted type of appearance and is esthetically desirable for an uncluttered look. Another object of this invention is to provide a novel form of dogging means for the actuator device wherein a spring biased dogging pin is concealed behind a small opening/aperture and yet is readily operable by authorized personnel by appropriately turning the dogging pin, depressing the panic bar, and releasing the dogging pin. A still further object is to provide such an arrangement in which, in the dogged position, the panic bar of the device is securely held in the depressed position by the dogging pin. Yet another object of the invention is to provide a novel actuator lever shaped to engage only the underside of the actuating pin of a conventional retraction mechanism to thereby allow the panic exit device to return to its normal, undepressed position even though the actuating pin remains in the upper, bolt retraction position. DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspective exploded view of an embodiment of the invention showing the mounting relationship of the actuator device the inactive and active stiles and mounting box. FIG. 2 is a sectional side elevation of an active door stile of the invention with the locking mechanism mounted therein and the actuator device mounted on the stile in the inactive position. FIG. 3 is a fragmentary sectional elevation of the active door stile taken from the interior side of the stile with the locking mechanism in the inactive position. FIG. 4 is a sectional side elevation of an active door stile of the invention showing the locking mechanism therein and actuator device mounted on the active stile in the active position. FIG. 5 is a fragmentary sectional elevation of the active door stile taken, from the interior side of the stile with the locking in the active position. FIGS. 6 and 7 are plan views of the latching mechanism taken along the line 6--6 and 7--7 shown in FIG. 3 and FIG. 5 respectively, with FIG. 6 illustrating the tripped configuration of the mechanism, such as when the door is closed, and FIG. 7 illustrating the configuration for swinging of the door. FIG. 8a is a fragmentary front view partially in section of a left side of an actuator device of the invention shown in the inactive position. FIG. 8b is a fragmentary front view partially in section of a right side of the actuator device of the invention shown in the inactive position. FIG. 9a is a fragmentary top view partially in section of the left side of the actuator device of the invention shown in the inactive position. FIG. 9b is a fragmentary top view partially in section of the right side of the actuator device of the invention shown in the inactive position. FIG. 10 is a fragmentary left end elevation partially in section of the actuator device of the invention shown in the inactive position. FIG. 11 is a fragmentary right end elevation partially in section of the actuator device of the invention shown in the inactive position. FIGS. 12a and 12b are fragmentary sectional elevations similar to FIGS. 9a and 9b of the actuator device of the invention shown active position. FIG. 13 is a fragmentary end elevation similar to FIG. 10 of the actuator device of the invention shown in the active position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment, depicted in FIG. 1, a panic exit device 20 of the invention is mounted in a door 21 having active stile 22 and inactive stile 23, it being understood that the term "active stile" merely refers to the edge of the door which opens and closes and "inactive stile" refers generally to the hinged side of the door. Although active stile 22 and inactive stile 23 as depicted are of a design suitable for framing a glass door, it is within the scope of the invention to mount the panic exit device in any type of door having an active stile as hereinafter described. Mounted internally in the active stile is a locking bolt retraction mechanism, generally designated 24 and more clearly depicted in FIGS. 2-5. The locking bolt retraction mechanism 24 is described in detail in U.S. Pat. No. 3,993,355 and includes connector rods 25 and 26 and springs 27 and 28 which urge the connector rods upwardly and downwardly respectively. Locking bolts 29 and 30 are threadably mounted on the end of connector rods 25 and 26 respectively so that in the normal locked, extended position they engage openings 31 and 32 in the doorway to lock the door in the closed position. The retraction mechanism 24 may be actuated to cause reciprocating vertical retraction movement of locking bolts 29 and 30 by inserting and turning a key in key mechanism 33, thereby rotating lever arm 34. Alternatively, the actuating mechanism may be actuated by the vertical movement of actuating pin 35. The retraction mechanism is essentially mounted in retraction mechanism case 36 which is securely fastened to active stile 22 by screws 37 and 38. Actuating pin 35 protrudes through slot 39 in case 36. Mounted through a front opening 40 of a housing 41 forming a rail 42 of the door, extending between the door stiles 22, 23 there is provided an actuator device embodying the principles of the present invention generally designated as 50 and more clearly depicted in FIGS. 8-13. The actuator device 50 is comprised of a mounting base 52 with control arms 54 and 56 pivotally mounted at first ends 58, 60 on vertical shafts 62 and 64 which are captured axially in openings 66, 68 in the base 52. Shafts 62 and 64 are secured by means of mounting brackets 70, 72, 74, 76. Each mounting bracket has a vertical hole 78 therethrough to accept one end of one of said shafts. The mounting brackets are attached to base 52 by appropriate fastening means such as screws 80. A panic bar 90 is attached to control arms 54 and 56 by means of rollers 92, 94, 96, 98 which are captured in channels 100, 102 formed integral in a top wall 104 and a bottom wall 106 of the panic bar 90. Rollers 92, 94, 96, 98 each have a hole 108 therein to accept shafts 110 and 112 which are mounted through holes 114 in second ends 116, 118 of control arms 54 and 56. The second ends 116, 118 of control arms 54 and 56 are connected together with upper and lower connecting links 120 and 122 which have holes 124, 126 therethrough to receive shafts 110 and 112. An outwardly biasing means for panic bar 90 is provided in the form of springs 128 and 130 which are contained by the encircling of end portions of said springs on shafts 62 and 64 in cut-outs 132, 134 at the first or pivotal ends 58, 60 of control arms 54 and 56. A central portion 136, 138 of said springs 128, 130 engages against a front face 140 of the base 52 and ends 142, 144 of the springs are held against an edge 146, 148 of the cutouts 132, 134 so that the control arms 54, 56 are constantly biased in a clockwise direction around an axis of shafts 62, 64 as seen in the view of FIGS. 9a and 9b. A maximum outward biased position of panic bar 90 is controlled by a stop mechanism 150, consisting of a washer 152 and fabric washer 154 positioned on a screw 156 which is placed into a slot 158 of control arm 56 and is accepted by a threaded insert 160 which is attached to a formed tab 162 of mounting base 52. When the panic bar 90 is depressed, the control arm 56 moves away from the washers 152, 154 and the slot 158 provides clearance for the screw 156. As the panic bar 90 returns to the outward position, the control arm 56 comes into engagement with the fabric washer 154 which cushions and silences the stopping impact. End covers 164 and 166 are attached to a rear edge 167 of panic bar 90 with screws 168, 170, 172, 174 and supported at a front edge 176 by tongues 178, 180 on end cover brackets 182 and 184, which fit into grooves 186, 188 on the inside of a front wall 190 of panic bar 90. The brackets 182, 184 are attached to end covers 164, 166 by screws 192. Further, end cover bracket 184 is supported by bosses 194, 196 on end cover 166 which provides a space or channel 198 for a controlling means 200 to prevent excessive lateral movement of the panic bar 90. The controlling means 200 comprises a roller 202 carried on a pin 204 which is attached to an end-play bracket 206, which in turn is secured to mounting base 52 by screws 208. The roller 202 rides in the space 198 between the end cover bracket 184 and the end cover 166 providing relatively linear movement of the panic bar in a direction normal to the front wall 190 of the panic bar 90. An actuating mechanism 210 consists of an L-shaped primary lever 212 having a long leg 214 with a distal end 216 and a short leg 218 with a distal end 220, the legs joining at junction 222. Rollers 224 and 226 are attached between side arms 228, 230 of the L-shaped lever 212 at the distal end 216 of the long leg 214 by pins 232, 233 placed in holes 234, 236 of the lever with the rollers contacting an underside face 238 of control arm 54. A roller 240 is attached in similar fashion at the junction 222 and contacts an actuator lever 242. Primary lever 212 is attached with a vertically oriented pin 244 through holes 246 in the lever near the distal end 220 of the short leg 218 and holes 248 in a primary lever bracket 250 thus allowing for pivotal motion of primary lever 212. Primary lever bracket 250 rests on a mounting plate 252 and is attached to the mounting base 52 through holes in the mounting plate. Another function of primary lever bracket 250 is to support and provide a pivotal bearing means for an end of a dogging pin 254. This bearing means is provided by a tab 256 with hole 258 for the dogging pin 254. The tab 256 also has a projecting member 260 for hooking one end 262 of a dogging pin spring 264. The actuator lever 242 is a right angle "L" shaped part with two arms 266, 268 extending, one of which (268) has a convex shape at a distal end 270 for engaging roller 240. The other arm 266 at a distal end 272 has a hole 274 for accepting a pin 276 which engages an actuator slide 278 through an aperture 280 in a slide cover 282. The actuator lever 242 has a hole 284 at a junction 286 where the arms 266, 268 of the lever converge and allows for pivotal movement around a horizontally oriented screw 288 which attaches the lever 242 to the mounting plate 252 through the hole 284. The actuator slide 278 engaged by the pin 276 is constrained to move only in a vertical linear manner. A slide cover 290 overlies the actuator slide 278 and forms a vertical channel 292 within which the slide 278 moves. The slide cover 290 rests on the mounting plate 252 and is attached to the mounting base 52 through holes in the mounting plate. Another function of the slide cover 290 is to support and provide a pivotal bearing means for an end 294 of dogging pin 254 which is accomplished by an outwardly protruding boss 296 and a hole 298 for pivotally receiving the end of the pin 254. Another function provided by the slide cover 290 is a limiting of the rotational movement of dogging pin 254. This is accomplished by outwardly directed tabs 300, 302 which are engageable by a roll pin 304 carried on the dogging pin 254. A slide lever 306 is attached to the rear side of actuator slide 290 by screws 308 engaging into holes provided in said actuator slide 290. Slide lever 306 has an arm 310 which is positioned under the actuating pin 35. The arm provides the vertical movement means for actuating pin 35. The dogging device consists of the dogging pin 254 which has the roll pin 304 mounted in a lateral hole 312 therein, projecting laterally therefrom. The dogging pin restraining means is best depicted in FIGS. 9 and 12. In this embodiment the dogging pin 254 is provided with relieved ends 314, 315 which are smaller in diameter than the body and are mounted in holes, the bottom hole 298 which is provided by the slide cover 290 and the top hole 258 which is provided by the tab 256 on the primary lever bracket 250. The dogging pin spring 264 with hooked ends 318, 262 is mounted on dogging pin 254, one end 318 of which is hooked around laterally mounted roll pin 304. The other end 262 of the spring 264 is hooked around the formed tab 260 on primary lever bracket 250, thus applying tension to roll pin 304. This forces one end 319 of the roll pin 304 against the formed outwardly projecting tab 300 on slide cover 290. In this position a second end 320 of the roll pin 304 is prevented from engaging a ledge 321 on end cover bracket 182 as depicted in FIG. 8. The panic bar 90 is provided with an aperture 322 near the active stile to allow passage of a dogging key 324 through to the dogging device. Dogging is accomplished by inserting the dogging key 324 through the aperture 322 to engage in a complementarily shaped recess 326 formed in the end 315 of the dogging pin. For example, the dogging key may have a hexagonal shape and the recess 326 would also be hexagonally shaped. The dogging key 324 is rotated clockwise 90° to move the one end 319 of the roll pin 304 away from the tab 300 and into engagement with the tab 302. In this orientation the roll pin 304 will be positioned vertically and laterally spaced from the ledge 321. The panic bar 90 can then be fully depressed, and when held in the fully depressed position, the dogging pin 254 is permitted to rotate counter-clockwise causing the second end 320 of the roll pin 304 to overlie the ledge 321 and lock the panic bar 90 in the active position. The panic bar can be undogged by rotating the dogging pin 254 clockwise with the dogging key 324 to disengage the second end 320 of the pin 304 from the ledge 321. The active position occurs when the panic bar 90 is depressed causing the rollers 92, 94, 96, 98 to roll in the channels 100, 102 of the panic bar 90 due to swinging arc motion of the control arms 54 and 56. The ledge 321 has a slot 327 to prevent engagement between the ledge 321 and the second end 320 of the roll pin 304 as the panic bar 90 is depressed. The underside face 238 of the control arm 54 pressing against the rollers 224 and 226 causes pivotal movement of the primary lever 212 and right to left motion of the roller 240. The roller 240 presses against the actuator lever 242 causing clockwise pivotal motion and upward movement of the pin 276, while the pin 276 engaged in the actuator slide 278, causes upward vertical movement of the actuator slide. The slide lever 306, being attached to the actuator slide 278, also moves vertically carrying with it the actuating pin 35 to move the bolts 29, 30 into the active position. When force on the panic bar is released, the springs 128 and 130 cause the panic bar 90 to move away from the mounting base 52. Since the actuator slide arm 310 engages only an underside of the actuating pin 35, it is free to move away from the pin, under the influences of gravity, even though the actuating pin 35 may remain in an elevated position. As discussed in U.S. Pat. No. 3,993,335 it is desireable to restrain the locking bolts 29, 30 in the retracted position while the door 21 is open. The latching means is best depicted in FIGS. 4, 6 and 7. In this embodiment locking bolt 29 is hexagonal in cross section and is provided with head portion 340 smaller in diameter than the body of locking bolt 29 and thus creating ledge 342 around the head portion. The latching means comprising slidable member 344, provided with aperture 346, is slidably mounted in mounting member 348 and biased in the latching position depicted in FIG. 7 by spring 350. When the door is in the closed position, protrusion 352 on slidable member 344 engages protrusion 354 connected to the doorway to force member 344 to the position depicted in FIG. 6 thereby disengaging bolt 29 and allowing it to freely pass through aperture 346. It can be seen that when retraction mechanism 24 is actuated to retract bolts 21 and 30, and active stile 22 is swung away from protrusion 354, slidable member 344 will assume the position shown in FIG. 7, and will restrain bolts 29 and 30 from returning to the locking position even after the key has been withdrawn from locking mechanism 33 or the upward force is removed from actuator pin 35. Locking bolts 29 and 30 have a hexagonal cross section, and support member 348 is provided with aperture 356 which has opposite sides spaced apart to slidably engage bolt, but to prevent it from rotating within support member 348. A similar apertured support member 358 is provided near the bottom of stile 22 having aperture 360 with opposite sides spaced apart to slidably engage bolt 30, but to prevent it from rotating therein. The configuration of support members 348 and 358 taken with the hexagonal cross section of bolts 29 and 30 and the fact that the bolts are threadably mounted on connector rods 25 and 26 allow fine adjustment of the distance bolts 29 and 30 protrude above the top and bottom of the door stile 22 respectively. This feature is important since it is desirable to have a high degree of flexability in adjusting the distance the bolts extend beyond the door stile. This distance is most often not known when the door is ordered and the adjustments must be made on the job. In installing a panic exit device of the invention, it is most usual to install the device on the door and then adjust the distance bolts 29 and 30 extend beyond the door in the locking position by rotating them on threaded shafts 25 and 26. Support members 348 and 358 are then installed to retain the bolts in the desired position. Should any changes in conditions occur, it is a simple matter to remove the support members and finely adjust the position of bolts 29 and 30. The hexagonal cross section of the bolt allows adjustments to be made in 1/6 increments of the thread flight length. Of course, other cross sectional shapes such as a square or octagon could be employed to allow different degrees of adjustment. As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceeding specification and description. It should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.	The invention disclosed herein provides a panic exit device for doors having in their active side vertically operating bolts extending from the top and bottom of the door and a mechanism for retracting the bolts. Usually, the retracting mechanism may be activated by using a key in an exterior door lock or by depressing a panic bar on the interior of the door. The improved panic exit device of this invention provide a device for actuating the bolt retraction mechanism which is mounted inside a semi-hollow enclosure which is integral with the door. The mounting is accomplished with screws hidden from view by the glass pane securing mouldings. The panic exit device of the invention also provides an improved dogging mechanism to lock the actuator device in the actuated position, while simultaneously preventing excessive play in the panic bar.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION The invention process is concerned with the enhanced recovery of oil from underground formations. More particularly, the invention relates to a method for recovering hydrocarbons with modified inverted 5 spot, modified inverted 9 spot and modified inverted 13 spot well patterns employing pairs of horizontal wells at the pattern corners instead of single vertical wells. Horizontal wells have been investigated and tested for oil recovery for quite some time. Although horizontal wells may in the future be proven economically successful to recover petroleum from many types of formations, at present, the use of horizontal wells is usually limited to formations containing highly viscous crude. It seems likely that horizontal wells will soon become a chief method of producing tar sand formations and other highly viscous oils which cannot be efficiently produced by conventional methods because of their high viscosity. Various proposals have been set forth for petroleum recovery with horizontal well schemes. Most have involved steam injection or in situ combustion with horizontal wells serving as both injection wells and producing wells. Steam and combustion processes have been employed to heat viscous formations to lower the viscosity of the petroleum as well as to provide the driving force to push the hydrocarbons toward a well. U.S. Pat. No. 4,283,088 illustrates the use of a system of radial horizontal wells, optionally in conjunction with an inverted 9 spot having an unsually large number of injection wells. U.S. Pat. No. 4,390,067 illustrates a scheme of using horizontal and vertical wells together to form a pentagonal shaped pattern which is labeled a "5 spot" in the patent, although the art recognizes a different pattern as constituting a 5 spot. SUMMARY OF THE INVENTION The invention is a pattern for recovering hydrocarbons from an underground formation by employing modified inverted 5 spot, modified inverted 9 spot and modified inverted 13 spot well patterns which contain several wells in which at least a portion of the wells extend through the formation in a substantially horizontal direction. Pairs of horizontal wells are substituted for the vertical wells drilled at the four corners of inverted 5 spot, inverted 9 spot and inverted 13 spot well patterns. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the invention well pattern for a modified inverted 5 spot pattern. FIG. 2 illustrates the invention well pattern for a modified involved 9 spot pattern. FIG. 3 illustrates the invention well pattern for a modified inverted 13 spot pattern. DETAILED DESCRIPTION Although they are more costly and difficult to drill, horizontal wells offer several advantages over vertical wells. One advantage is the increase in direct contact between the wellbore and the pay zone. The perforated interval per vertical well is limited to the pay zone thickness. But for a horizontal well, the perforated interval could be more than ten times that of a vertical wellbore. For example, a 400 foot horizontal well could be run in a 30 foot thick pay zone. A second advantage of horizontal wells is the ability to complete several horizontal wells from a single location and cover a large drainage area. This is an important advantage when drilling in offshore, Arctic or environmentally sensitive areas where drill site preparation is a major expense. Thirdly, vertical drilling can be uneconomical in very thin pay zone areas. Properly placed horizontal wells can solve this problem. For certain thin formations with a bottom water table, horizontal wells could defer and reduce water coning by providing a low pressure area over a long distance rather than a single low pressure point as with vertical wells. A fourth advantage is the ability to inject or produce fluids orthogonal to those from a vertical well. This provides potential of improving sweep efficiency of a flood and therefore increasing recovery efficiency. However, horizontal wells are significantly more expensive to drill than vertical wells. In addition, all existing hydrocarbon reservoirs have vertical wells which have already been drilled in the reservoirs. Thus, ways must be found to coordinate the use of horizontal wells with existing vertical well patterns. The invention provides a way of achieving horizontal well advantages by using substantially horizontal wells in conjunction with substantially vertical wells for improving oil recovery efficiency. The invention requires that a pair of substantially horizontal wells be drilled at each corner of inverted 5 spot, inverted 9 spot and inverted 13 spot patterns. Each pair of horizontal production wells are drilled to form an X-shaped areal pattern. Preferably, angles are formed between the horizontal wells in each pair of about 40 degrees to about 140 degrees, most preferably, about 80 degrees to about 100 degrees. Generally, oil recovery efficiency will decrease as the angles between the horizontal wells move further away from 90 degrees. But certain formation characteristics may make it desirable to locate the horizontal wells to form angles other than 90 degrees. The horizontal wells should be drilled in the bottom third, most preferably, the bottom fifth of the hydrocarbon formation to take full advantage of horizontal well production properties. Preferably, the horizontal wells in each pair are completed at different vertical depths without a communication path between the horizontal wells. However, this is not essential. FIGS. 1, 2 and 3 diagram the invention drilling and production patterns. In all three figures, wells 12, 13, 14, 15, 16, 17, 18 and 19 are horizontal production wells drilled at the corners of the modified inverted 5 spot, modified inverted 9 spot and modified inverted 13 spot patterns of FIGS. 1, 2 and 3, respectively. Well 11 is the substantially vertical central injection well. For some patterns, particularly patterns covering a large area, it may be desirable to substitute several vertical injection wells for the single injection well 11 and locate the plural central injectors near the center of the pattern. Wells 21, 22, 23 and 24 are injection side wells. Under some operations, these side wells may also be production wells or a mixture of injection and production wells. Wells 31, 32, 33 and 34 of FIG. 3 are infill wells. The infill wells 31-34 are normally used as production wells, but under some operational procedures, may be converted to injection wells as is well known in the art. Simulation results indicate that the use of horizontal wells in conjunction with vertical wells according to the invention are highly effective in recovering oil, particularly oil from blind spot areas in mature steam floods. The horizontal wells speed oil recovery and thus, shorten project lives. Although the invention method may be practiced in most hydrocarbon reservoirs, production economics will probably limit its use to thermal recovery in heavy oil reservoirs for the next few years. Horizontal wells must extend from the surface and run a substantially horizontal distance within the hydrocarbon formation. The diameter and length of the horizontal wells in their perforation intervals are not critical, except that such factors will affect the well spacing and the economics of the process. Perforation size will be a function of factors such as flow rate, temperatures and pressures employed in a given operation. Such decisions should be determined by conventional drilling criteria, the characteristics of the specific formation, the economics of a given situation, and the well known art of drilling horizontal wells. The following examples will illustrate the invention. They are given by way of illustration and not as limitations on the scope of the invention. Thus, it should be understood that a process can be varied from the description and the examples and still remain within the scope of the invention. EXAMPLES A commercially available 3-dimensional numerical simulator developed for thermal recovery operations was employed for the examples. The model used was "Combustion and Steamflood Model-THERM" by Scientific Software-Intercomp. The model accounts for three phase flow described by Darcy's flow equation and includes gravity, viscous and capillary forces. Heat transfer is modeled by conduction and convection. Relative permeability curves are temperature dependent. The model is capable of simulating well completions in any direction (vertical, horizontal, inclined or branched). Reservoir properties used in the study are typical of a California heavy oil reservoir with unconsolidated sand. A dead oil with an API gravity of 13 degrees was used in the simulation. The assumed reservoir properties are listed in Table 1. EXAMPLE 1 An 18.5 acre (7.5 ha) inverted 9 spot pattern was used as a basis for this simulation study. The 125-foot (38-m) thick formation is divided into five equal layers. All wells were completed in the lower 60% of the oil sand. Steam at 65% quality was injected into the central well at a constant rate of 2400 BPD (381 m 3 /d) cold water equivalent. The project was terminated when the fuel required to generate steam was equivalent to the oil produced from the pattern or instantaneous steam-oil ratio (SOR) of 15. A maximum lifting capacity of 1000 BPD (159 m 3 /d) was assumed for each producing well. The resulting oil recovery at the end of the project life (15 years) was 64.7% of the original oil in place. The predicted oil saturation profile indicates a good steam sweep throughout the upper three layers to an oil saturation less than 0.2 (the upper 60% of the oil zone), but steam bypassed most of the lower two layers except near the injection well. EXAMPLE 2 Infill wells were added to the simulation grid midway between center and corner wells to form an inverted 13 spot pattern. The wells were completed in the lower one-third of the zone only and infill production began after three years of steam injection and continued to the end of the project. Ultimate recovery was 63.2% of the original oil in place after 11 years. Note that the advantage of infill wells is to recover oil sooner. For the inverted 9 spot pattern of Ex. 1, the oil recovery at 11 years would have been only 57% at this time. Because of the presence of infill wells, oil production which would otherwise arrive at corner and side wells will be reduced. As a result, the inverted 13 spot pattern would reach economic limit much sooner than an inverted 9 spot pattern unless other operational changes are made. The oil saturation profile for Example 2 is about the same as for Ex. 1, but is reached four years sooner than in Ex. 1. There is still a high oil saturation region in the area between the corner and side wells. EXAMPLE 3 The modified inverted 9 spot of FIG. 2 was simulated and compared with the base cases of Examples 1 and 2. This configuration has three vertical injection wells and two horizontal producers per pattern. The run was carried out with an 18.5 acre (7.5-ha) pattern and an injection rate of 3900 BPD (620 m 3 /d) or 1.7 BPD per acre foot. Vertical wells were completed in the lower three layers of the simulation grid only and all horizontal wells were completed in the bottom (fifth layer) of the simulation grid. The horizontal wells had a length of 635 feet and a diameter of six inches. They extended towards the central injection well for a distance of about 318 feet from the corner position of the pattern, which was about half the distance from the corner wells to the central well. 90 degree angles were formed between the crossed horizontal wells. Ultimate recovery was 72.2% of the original oil in place at the end of a seven year project life and 1.4 pore volumes of steam injection. After only seven years, the average oil saturation was 15% in the upper 60% of the oil zone and 26% of the lower 40%. The areal and vertical conformance were good and only minimum steam override had occurred. EXAMPLE 4 A conversion to hot water injection after seven years of central well injection for Example 3 was made and the results indicated the ultimate oil recovery could reach 74.7% at 10 years. An average oil saturation in the lower 40% of the oil zone could be reduced to 21%, compared to the 26% of Example 3. Many variations of the method of this invention will be apparent to those skilled in the art from the foregoing discussion and examples. Variations can be made without departing from the scope and spirit of the following claims. t,0120	The disclosed invention is a pattern for recovering hydrocarbons by employing modified inverted 5 spot, modified inverted 9 spot and modified inverted 13 spot well patterns which contain pairs of horizontal wells substituted for the vertical wells drilled at the four corners of the well patterns.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION (a) Field of the Invention The present invention relates to a braking device for the ladder lifter of a fire-fighting or high-altitude working extensible ladder truck. (B) Description of the Prior Art The conventional braking device comprises a hook lever pivotally mounted on a crosspiece of a ladder. Normally said lever is locked in its retracted position on the lifter side, but when the lifting wire rope is broken, the lever is automatically released and swung into engagement with the associated crosspiece, thereby preventing the lowering of the lifter. According to this arrangement, although it is possible to stop the lifter in this manner by making use of the constant spacing between adjacent crosspieces of the ladder when the rope breaks, it sometimes occurs that the lifter falls through a distance up to said crosspiece spacing from the position assumed by the lifter when the rope breaks, giving the rider a great shock or a feeling of uneasiness. SUMMARY OF THE INVENTION The present invention provides a braking device for a ladder lifter, characterized in that it comprises a brake cam rotatably mounted on a lifter frame on a ladder rail and opposed to the rail, a spring installed between said lifter frame and said cam and urging the cam to be rotated and pressed against the rail, and a lifter lifting wire rope fastened to a cam lever in such a manner as to cause the cam to be retracted against the force of the spring when said wire rope is tensioned, the arrangement being such that normally the lifter is allowed to be lifted and lowered and stopped as desired, but upon breakage of the wire rope, the brake cam is actuated to brake the lifter so that the latter is securely stopped without falling, at whatever position the lifter assumes on the rail at the time of breakage of the wire rope. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings illustrating a preferred embodiment of the present invention: FIG. 1 is a perspective view of a ladder lifter equipped with a braking device according to the invention; FIG. 2 is a front view, in longitudinal section, of a cam attaching section; and FIG. 3 is a side view of said section. DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, a 6-stage extensible ladder designated at 1 comprises channel-shaped unit ladders 1a, 1b, 1c, 1d, 1e and 1f of the same length but successively reduced in width so that they are extensibly mounted in each other through rollers (not shown). Each unit ladder is formed at its top on both sides with rails 2 outwardly projecting and extending parallel to each other and in the same plane. Designated at A is a lifter adapted to be lifted and lowered along the rails, and 3 designates a frame therefor. The lifter frame consists of cross members 3a, 3b and side members 3c, 3d, said cross members being positioned astride the rails 2. Axles 4, 5 are supported between suspension arms 3e, 3f at opposite ends of the cross members 3a, 3b. Wheels 6, as shown in FIGS. 2 and 3, are mounted on the axles so that they may roll on the respective rails while carrying the lifter A. It is so arranged that as the lifter A is lifted and lowered with the ladder 1 extended, the lifter is transferred from one unit ladder to another while assuring smooth switching to the rotation of the corresponding wheels associated with said another unit rail. The lifting and lowering of the lifter A is effected by a lifting wire rope 7. The rope extends from a winch drum fixed on a support table for the ladder base, passing in zigzags around pulleys at the bases and front ends of the unit ladders and extending from around the pulley at the front end of the uppermost unit ladder 1f to the lifter, to which it is then fastened. During extension and contraction of the ladder, the lifter is maintained stationary on the rear portion of the sixth stage ladder 1a. With the ladder 1 held in its erected and extended position, said drum is rotated for winding the rope to lift the lifter. At the time of lowering the lifter, said drum is rotated for unwinding the rope to allow the lifter to descend by its own weight and the weight of the rider. Therefore, if the wire rope 7 breaks when the ladder has been erected, the lifter will slide down the rails. To prevent this, the following braking device is provided. A pair of cam shafts 8 are provided rearwardly of the right and left rows of wheels 6 associated with the cross member 3a and extend parallel to the axles 4. Each cam shaft is rotatably supported by arms 3e transversely and parallelly spaced on and extending downwardly from the lower surface of the cross mamber 3a. Brake cams 9 are fixedly mounted on each cam shaft 8 so as to be opposed to the upper surfaces of the rails 2. As shown in FIG. 3, each cam 9 is formed rearwardly with a raised portion so that when it is rotated in a clockwise direction the raised portion is pressed against the opposed rail 2, thereby preventing the rightward movement as viewed in the Figure, or the lowering, of the lifter A. The cam surface 9a has irregularities such as, for example as shown, a serrated surface fit for prevention of slippage between the cam and the rail. A band plate 10 having a irregular surface 10a, such as, for example as shown, a serrated surface adapted to mesh with said irregularites is fixed to the rail 2 throughout the length thereof to further ensure the brake action. The inner end of each cam shaft 8 has a lever 11 fixed thereto and extending therefrom and a coiled spring 13 is installed under tension between the front end of said lever 11 and a bracket 12 fixed to the frame 3, so that a clockwise torque acts on the cam shaft 8 at all times. Disposed rearwardly of the lever 11 is an L-shaped lever 15 pivotally mounted on a bracket 17 extending from the frame 3 by means of a pivot pin 16. A wire rope or link 18 is connected between the upwardly extending portion 15a of the lever 15 and the front end of the lever 11 while the lifter lifting wire rope 7 is tied to the horizontal portion 15b of the lever 15. As shown in FIG. 2, the arms 3e, except the outermost one, are suspended from the cross member 3a outside the respective associated rails by making use of the spacing between adjacent parallel rails. The lower portion 3f of each arm 3e is bent in an L-shape to extend under the associated rail with a suitable spacing therebetween. To ensure brakage the surface of the projecting lower portion 3f opposed to the rail is provided with a friction plate 19. Designated at 20 is a recess for reception of the same. FIG. 3 illustrates a condition in which the ladder 1 is erected and the lifting wire rope 7 is under tension. In this condition, the lowering, or rightward movement of the lifter A under loads as viewed in the Figure is restrained by the rope 7 payed out from the ladder front end at the left, through the lever 15, pin 16 and bracket 17. The horizontal arm 15b of the lever 15 is shown turned to a position where it is parallel to the ladder rail 2. The erected arm 15a is shown turned clockwise to turn the lever 11 to the right against the force of the spring 13 through the rope or link 18. As a result, the cams 9 have been shifted away a suitable distance from the respective associated rails 2. In this condition, if the rope 7 is wound, unwound or stopped by the winch, the lifter A will be lifted, lowered or stopped without hindrance. If the rope 7 should break to lose its tension during such operation, the lever 11 would be instantly swung in a clockwise direction by the tension in the spring 13. Thus, no matter what position on the ladder rails the lifter may assume, the cams on that rail are turned and pressed against the rail. Concurrently therewith, the lifter A is slightly floated up above the upper surface of the rail so that the projecting lower portion 3f of the arm below the rail is lifted and pressed against the lower surface of the rail. In other words, the rail 2 is clamped between the cams 9 and the projecting lower portions 3f of the arms and the cams 9 are locked against the rail, so that the lifter is braked and stopped. In this case, since the row of brake cams 9 and the row of clamp arms 3e forming pairs therewith are installed in the front cross member 3a, the lifter is floated up with the rail-engaging wheels in the rear cross member 3b serving as a fulcrum. The rear cross member 3b is provided with a step 21 as shown in FIG. 1 and since the operator stands on this step, the distribution of the load on the lifter is such that coupled with the ladder inclination, the rear portion of the lifter is more heavily loaded than the front portion thereof, enabling said floating-up to be effected more smoothly. As a result, the clamping of the rails by the cams and arms is ensured. Further, since the rows of brake cams and arms are disposed on both sides corresponding to the right and left rails, the lifter can be floated up uniformly and symmetrically with respect to the right and left sides, so that the stability is high. Further, since the right and left cam shafts are separate from each other, they can be securely and individually operated without being interfered with by each other. Further, the cams and the upper surfaces of the rails are prevented from slipping relative to each other by the meshing between their irregularities, and the lower surfaces of the rails and the arms are pressed against each other through the friction plates 19, so that there is no danger of slip occurring when the lifter is braked and stopped. In addition, thereafter, the broken wire rope 7 will be pieced together or replaced by a new one. When the ladder lies flat on the ladder truck, there is no tension acting on the wire rope 7, so that brakage acts on the lifter during running of the truck. While the above embodiment refers to an extensible ladder, the invention may also be applied to a single-ladder lifter. Further, the cam shafts may not be separate from each other but they may be combined into a single shaft. Further, the L-shaped lever may be directly fixed to the cam shaft and the lifter lifting wire rope may then be fastened to the horizontal arm with a spring connected to the suspension arm.	There is provided a cam type braking device for a ladder lifter arranged so that as soon as the lifting wire rope for the ladder lifter is broken, a brake cam is pressed against the associated ladder rail, whereby the lifter is braked and it is securely stopped at the position on the rail which it assumed at the time of breakage of the wire rope, without causing any large fall of the lifter.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATIONS [0001] U.S. Provisional Application No. 61/442,149 for this invention was filed on Feb. 11, 2011 for which application this inventor claims domestic priority. BACKGROUND OF THE INVENTION [0002] This invention generally relates to vacuum excavation methods, and more particularly to devices which may be utilized for clearing rocks and other objects from the generally vertical excavation formed in the vacuum excavation process. [0003] Air vacuum excavation, which is also known as potholing, is an excavation methodology which is utilized to expose utilities to ascertain the exact depth and location of the utilities, typically in preparation for more extensive excavation done in the process of construction activities. Because it is intended to cause a relatively small amount of disruption, air vacuum excavation generally utilizes a small diameter excavation to accomplish this purpose. The larger pieces of equipment utilized for the excavation, such as the vacuum truck, air compressor, etc., may be generally located to the side of the excavation, thereby allowing the survey to take place without major disruptions in surface operations occurring at the site, which is most commonly vehicle traffic along a roadway. Precisely locating underground utilities help the designers to plan construction projects to eliminate potential damage to the utilities and avoiding unnecessary relocations. Air vacuum excavation uses a combination of high-pressure air and a powerful vacuum to safely remove the soil above and around the utility eliminating the risk of damaging the utility which might otherwise occur utilizing traditional methods of mechanical excavation. After the pothole is completed and the utility data is collected then the excavation is backfilled. [0004] So long as the material removed from the excavation during the potholing process is soil, the vacuum excavation process works very well. Because the material being removed is usually backfill, it would be expected that the material being removed would be compacted soil. However, it is not unknown for excavations to be filled with other materials, such as rocks, asphalt and concrete chunks, and other objects and materials. [0005] If larger objects are encountered during the potholing process, major problems can arise. For example, if a large rock is encountered during the excavation, it is necessary to either remove the rock, or to change the location of the pothole. Under the known methods, the rock is typically eliminated by enlarging the excavation with a backhoe or other mechanical excavation machinery and either breaking up the rock with a jack hammer or chisel, or removing the rock. However, utilizing these methods eliminates the primary advantages of potholing, including that it is generally non-destructive and relatively inexpensive. [0006] It is to be appreciated that the present invention may have utility in excavations created by methods other than vacuum excavation and used for purposes other than ascertaining the location of utilities. For example, drilled shafts (also called caissons, drilled piers or pile borings) may be used for bridges and structures where large loads and lateral resistance are major factors. There are a variety of tools utilized by construction contractors when constructing these types of excavations. However, regardless of the type of equipment used, hard rock and individual rock bodies and fragments are often encountered and often the excavation tool cannot advance until the rock is removed. Removal of the rock bodies and fragments can be a laborious and time consuming task to accomplish, particularly if specialized and/or expensive equipment is required to be brought on site for removal. In addition, the utilization of this equipment may require shutting down normal activities for mobilization and operation of the equipment, such as limiting or closing down traffic on a roadway. Accordingly, a need exists for a device which is capable of removing objects from a generally vertical excavation where the device is readily available, relatively compact, and relatively inexpensive. SUMMARY OF THE INVENTION [0007] The present invention, a grasping device for retrieving objects from generally vertical excavations, satisfies the need described above by providing a device that is convenient and easy to use, manually deployable, durable yet lightweight in design, versatile in its applications and allows anyone drilling or digging a hole to move rocks and rock fragments from a vertical excavation or potholing operation. [0008] One embodiment of the device has a handle member comprising a length of tubing having a grasping surface which is manually grasped by the user as the grasping apparatus is lowered into the excavation. Depending from the handle member is a frame member. Attached to the lower end of the frame member is a pivot plate. A pair of opposite facing jaw members depend from the pivot plate. Each of the jaw members is pivotably attached to the pivot plate. A ram member, which may be pneumatically actuated, is operationally linked between at least one of the jaw members and the frame member. Operation of the ram by, for example, providing an air supply to cause the ram piston to retract into the cylinder, causes the opposite facing jaw members to open for receiving the rock or other object disposed within the vertical excavation. The ram may also be operated by releasing the air pressure such that air exhausts from the ram, which allows the jaw members to close around the object, allowing for its retrieval from the vertical excavation. Biasing means, such as helical torsion springs, may be utilized to maintain the jaw members in a closed position until opened by operation of the ram. BRIEF DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 is side perspective view of an embodiment of the disclosed apparatus with the opposite facing jaws in a closed position. [0010] FIG. 2 is a second perspective view of an embodiment of the disclosed apparatus. [0011] FIG. 3 shows a front view of an embodiment of the disclosed apparatus with the opposite facing jaws in an open position. [0012] FIG. 4 is side perspective view of an embodiment of the disclosed apparatus. [0013] FIG. 5 is a front view of an embodiment of the disclosed apparatus. [0014] FIG. 6 is a perspective view of an embodiment of the opposite facing jaws of the disclosed apparatus. [0015] FIG. 7 is an exploded view of an embodiment of the opposite facing jaws of the disclosed apparatus. [0016] FIG. 8 shows an embodiment of the apparatus being manually lowered to retrieve an object in a generally vertical excavation DETAILED DESCRIPTION OF THE INVENTION [0017] Referring now to the figures, embodiments of the present invention will now be described more fully hereinafter. The invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. [0018] The present invention is a grasping apparatus which is utilized for retrieving objects from generally vertical excavations such as potholes, boreholes, drilled shafts, etc. Rather than requiring attachment to machinery, such as the articulating arm of a backhoe, the present invention is manually lowered into the excavation by the user. Manual deployment is often effective for potholes because the objects routinely encountered in excavations made in backfilled utility installations are relatively small in size, allowing a single person to manually lift an object out of the excavation. The manual deployment of the invention is one of the most attractive features of the invention, because it simplifies mobilization and utilization of the apparatus, and minimizes disruption of other activities at the worksite. [0019] An embodiment of the grasping apparatus is depicted in FIGS. 1 through 8 . As shown in the figures, an embodiment of the apparatus 10 has a first jaw member 12 and a second jaw member 14 , each depending from and pivotably attached to a pivot plate 16 . The first jaw member 12 and the second jaw member 14 are placed in opposite facing relation. A frame member 18 and pivot plate 16 are connected together. In the embodiment of the apparatus 10 depicted in the figures, the frame member 18 generally has a tee configuration, where a pair of pivot plates 16 are attached to the cross-member of the tee. [0020] The figures show the first jaw member 12 and second jaw member 14 as each made up from parallel blade members 20 , 22 , with each blade member having a plurality of teeth members 24 . The teeth members of the jaw members 12 , 14 are in general facing relationship with the teeth members of the opposite facing jaw member. The teeth members 24 may either be integral components of the blade members 20 , 22 , or the teeth members may be separately attached to the blade members with fastening means known in the art. The blade members 20 , 22 are attached together with cross-members 26 . However, it is to be appreciated that the first jaw member 12 and second jaw member 14 may also be fabricated as solid units as opposed to the blade/cross-member construction utilized in the embodiments shown in the figures. [0021] The top of the frame member 18 comprises a connector 28 for attaching a handle member 30 to the tool body, which comprises the jaw members 12 , 14 , frame member 18 , and other functional components. The handle member 30 is generally one or more lengths of tubing which are manually grasped by a user as the apparatus 10 is lowered into and raised out of a vertical excavation 100 . The handle member 30 comprises a grasping surface 32 along its length which passes through the user's hands. This grasping surface 32 may be knurled, textured, or have other means for improving the user's ability to maintain a grip on the handle member 30 . The handle member 30 may have a length which may be adjusted by either connecting extensions to the handle member with conventional couplings, or utilizing a telescoping handle member 30 . Thus the operational depth of the apparatus is not limited by the handle length. [0022] The apparatus 10 will typically use one or more rams 34 for manipulating the jaw members 12 , 14 . The rams 34 comprise a piston 36 and a cylinder 38 . The rams 34 are operationally linked between at least one of the jaw members 12 , 14 and the frame member 18 . One end of the ram may be attached to either one or both of the jaw members 12 , 14 , by connecting to an appropriate structure, such as attaching the piston 36 to cross-member 26 as shown, for example, in FIG. 2 . The opposite end of the ram 34 is attached to the frame member 18 or to structures appurtenant to the frame member, such as extension members 48 as shown in the figures. It is to be appreciated that utilization of linkage systems not depicted in the figures may accomplish the same result of manipulating the jaw members 12 , 14 to open and closed positions by utilizing two rams 34 as depicted in the figures, a single ram, or more than two rams. [0023] The inventor herein has found that pneumatic rams function particularly well as rams 34 for the apparatus 10 . The pneumatic rams 34 receive air (or other suitable operational gas, all collectively referred to herein as “air”) when an air valve 40 is opened by the user. Air is exhausted from the rams 34 when the air valve 40 is closed. The air is exhausted from the rams 34 through integral exhaust ports and air is exhausted from the frame member 18 and handle member 30 through exhaust port 42 . The handle member 30 may comprise an air conduit for operation of the rams 34 . The air conduit may be an independent line running in parallel with the handle member 30 or, as shown in FIG. 8 , be integral to the handle member, where the handle itself is the conduit. As further shown in FIG. 8 , an air supply means, such as compressor 44 is connected to the air conduit, in this case handle member 30 , where the air valve 40 is disposed between the air supply means and the air conduit. Air from the handle member 30 may be delivered to each of the rams 34 through lines 50 . The rams 34 may be configured such that pressurization of the rams 34 by opening air valve 40 causes retraction of the piston 36 into cylinder 38 , which manipulates jaw members 12 , 14 into an open position as depicted in FIG. 3 . Release of pressure by closing air valve 40 causes piston 36 to extend from cylinder 38 , allowing jaw members 12 , 14 to move into a closed position. It is to be appreciated that, alternatively, the rams 34 may be configured to manipulate the jaw members 12 , 14 into the closed position by pressurization of the rams, and into the open position by release of the pressure. In this configuration, the rams 34 would be of the type where the piston 36 would extend from the cylinder 38 upon pressurization of the ram. [0024] FIG. 3 depicts the apparatus 10 in an open position, while the other figures depict the apparatus in a closed position. In one embodiment, the apparatus 10 is biased in the closed position by biasing means, such as helical torsion springs 46 , with the springs retained by spring pins 52 , where the spring pins prevent the springs from rotating thus allowing the springs to be placed in torsion by the opening of the jaw members 12 , 14 . Alternatively, the springs may be placed in torsion by the closing of the jaw members 12 , 14 . In an embodiment of the device which is sized for application in commonly sized vacuum excavations, the jaw members 12 , 14 may open as widely apart at 22 inches and close to within approximately 7½ inches apart. [0025] Use of the apparatus 10 is depicted in FIG. 8 . The apparatus 10 is manually lowered into a generally vertical excavation 100 . Once the apparatus is adjacent to the object to be retrieved, in this case a rock 102 , the apparatus is placed into the open position (as depicted in FIG. 3 ) by pressurizing the rams 34 with a fluid, such as air in the case of pneumatic rams. Pressuring the rams 34 , causes the opposite facing jaw members 12 , 14 to move into the open position, allowing the apparatus 10 to be placed over and receive the rock 102 . Once the rock 102 has been received by the opposite facing jaw members 12 , 14 , pressure is released from the rams 34 by closing the air valve 40 , usually by releasing an activation lever, and allowing the air to vent through the ram exhausts and through exhaust port 42 . When the pressure is released from the rams 34 , the object is captured between the opposite facing jaw members 12 , 14 . The closing of the jaw members 12 , 14 may be facilitated by the use of a biasing means, such as helical torsion springs 46 . Once the rock 102 has been captured inside the jaw members, the apparatus 10 may be raised through the vertical excavation and the rock removed by moving the opposite facing jaw members 12 , 14 into the open position. [0026] The jaw members 12 , 14 may be configured in such a shape and tooth configuration such that the weight of the object being retrieved acts to reinforce the closed position of the jaw members. That is, the gravitational force of the object, such as rock 102 , has a resultant force which acts to force the jaw members 12 , 14 together rather than apart. [0027] While the above is a description of various embodiments of the present invention, further modifications may be employed without departing from the spirit and scope of the present invention. Thus the scope of the invention should not be limited according to these factors, but according to the following appended claims.	A manually deployed grasping apparatus may be utilized for retrieving objects, such as rocks, concrete chunks and other debris, from vertical excavations such as potholes, boreholes, drilled shafts, etc. Unlike backhoes and other articulated arm machinery, the disclosed grasping apparatus is manually lowered into the excavation by the user. Once the apparatus is adjacent to the object to be retrieved, the opposite facing jaw members of the apparatus are placed into an open position to receive the object. Once the object has been received by the opposite facing jaw members, the jaw members are closed to capture the object. The jaw members are then manually withdrawn from the vertical excavation to retrieve the object.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of provisional application U.S. Ser. No. 60/232,898, filed on Sep. 15, 2000 TECHNICAL FIELD This invention relates in general to a threaded connection between two tubular elements, each having a pin member on one end and a box member on the other end. In particular, this invention relates to a threaded connection for use with offshore riser pipe. BACKGROUND OF THE INVENTION In offshore production applications, a plurality of tubular riser elements are joined together in an end-to-end configuration and extend from a subsea well assembly to a surface platform. Advances in drilling technology have made it possible to drill at greater water depths, subjecting the production risers to extremely high pressures and bending loads. Metal-to-metal seals can provide an effective seal under these harsh conditions; however, contamination, pitting, or damage to the seal surfaces causes these seals to deteriorate rapidly. Thermoplastic seal elements can be used as secondary sealing elements; however, these components typically resist radial compression and therefore create internal forces which act to urge the box and pin elements apart. Bending loads due to currents and wave motion can cause the metal seals to cycle, creating fatigue. This in turn reduces the effectiveness of the metal-to-metal seals, contributing to the failure of the connection. Attempts have been made to overcome these problems. For example, U.S. Pat. No. 4,707,001 discloses a connection featuring multi-start threads with a reverse angle load flank in conjunction with a torque shoulder seal to lock the pin and box against radial separation. While this design may be workable, the torque shoulder could create plastic deformation in the box or pin member if too much torque is applied to the connection. This design is also susceptible to stress fractures because the torque shoulder seal applies repetitive bending loads to the box and pin. SUMMARY OF THE INVENTION The connection of this invention features a box member with an internal thread an a pin member with a cooperative external thread. A first metal-to-metal seal located adjacent to the box shoulder forms the primary internal seal of the connection. A second metal-to-metal seal located near the box end forms the primary external seal of the connection. Guide surfaces located on the pin end and box end protect the metal sealing surfaces from damage during makeup. A dual angle torque shoulder in combination with a large blend radius is located on the pin member for engaging a corresponding dual angle box end, locking the box end securely into place against the pin. This configuration is self-centering. The dual angle torque shoulder has inner and outer inclined surfaces that join each other with a large blend radius. The dual angle torque shoulder in combination with the large blend radius self-centers, prevents radial distention of the box end, and maintains bearing pressure between the external sealing surfaces. Because the torque shoulder has a dual angle configuration, the pin and box will not undergo plastic deformation as a result of excessive torque. The torque shoulder on the box end is generally torroidal, being convex in cross-section. The connection also has stress relief grooves located on the box member and on the pin member. These stress relief grooves reduce the incidence of stress fractures, thereby improving the fatigue life of the connection. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a tubular connection according to the invention, showing the dual angle torque shoulder and the double stress relief grooves. FIG. 2 is an enlarged cross-sectional view of the end of the box member of the connection of FIG. 1, showing the detail of the dual angle torque shoulder. FIG. 3 is an enlarged cross-sectional view of the nose of the pin member and the base of the box member of the connection of FIG. 1 . FIG. 4 is a cross-sectional view of the pin member of FIG. 1, shown stabbing into the box member of FIG. 1, and illustrating common misalignment that occurs during stabbing. FIG. 5 is an enlarged cross-sectional view of an upper portion of the pin and box members shown in the position of FIG. 4 . FIG. 6 is an enlarged cross-sectional view of a lower portion of the pin and box members shown in the position of FIG. 4 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the tubular connection or pipe joint 10 of a pin member 12 and box member 14 is shown. Pin 12 has an external thread 16 and extends from a pin end 18 to a dual angle torque shoulder 20 . In a similar manner, box 14 has a cooperative internal thread 22 and extends from a box end 24 to a box shoulder 26 . Threads 16 and 22 preferably have rounded roots. Referring to FIG. 2, dual angle torque shoulder 20 on pin member 12 is generally concave and comprises two conical surfaces: an outer surface 20 a having a negative draft angle with respect to the outer surface of the tubular element, and an inner surface 20 b extending inward from outer surface 20 a and having a positive draft angle with respect to the outer surface of the tubular element. Outer surface 20 a extends downward and outward from the intersection with inner surface 20 b . Inner surface 20 b extends downward and inward from its intersection with outer surface 20 a . The angle of outer surface 20 a relative to a plane perpendicular to the longitudinal axis of the connection 10 is approximately 30 degrees negative in the preferred embodiment. The angle of inner surface 20 b relative to the same plane is approximately 5 degrees positive. These angles may differ, however. Outer surface 20 a and inner surface 20 b are formed so that the angle between surfaces 20 a and 20 b must be less than 180°, and in the preferred embodiment is approximately 150°. The width of outer surface 20 a may be larger than inner surface 20 b or vice-versa. A large blend radius of approximately 0.15 inch blends the junction of the two surfaces 20 a and 20 b . The outer and inner surfaces generally define an annular channel with a concave configuration. Box end 24 comprises mating outer and inner conical surfaces, generally defining a convex configuration or a toroid, so that the box end 24 fits securely within the dual angle torque shoulder 20 . This configuration locks the box end 24 securely into place against the pin 12 , preventing radial distention of the box end 24 . The primary internal seal of the connection 10 is formed adjacent to the box shoulder 26 between an outwardly facing internal sealing surface 28 on pin 12 and an inwardly facing internal sealing surface 30 on box 14 . This primary internal seal is an interference seal formed by the metal-to-metal contact between surfaces 28 and 30 , as is well known in the art. Sealing surfaces 28 and 30 can be tapered. As shown in FIG. 3, metal seal surface 28 on the nose of pin 12 is recessed from a guide surface 29 located directly above. That is, the outer diameter of seal surface 28 is less than the outer diameter of guide surface 29 . The primary internal seal of the connection 10 is formed adjacent to the box shoulder 26 between an outwardly facing internal sealing surface 28 on pin 12 and an inwardly facing internal sealing surface 30 on box 14 . This primary internal seal is an interference seal formed by the metal-to-metal contact between surfaces 28 and 30 , as is well known in the art. Sealing surfaces 28 and 30 can be tapered. As shown in FIG. 3, metal seal surface 28 on the nose of pin 12 is recessed from a guide surface 29 located directly above. That is, the outer diameter of seal surface 28 is less than the outer diameter of guide surface 29 . Guide surface 29 is conical and, relative to the longitudinal axis of box 14 , is formed at an angle larger than the taper angle of internal thread 22 , as indicated by the numeral 31 in FIG. 3 . Also, a tangent line extending from guide surface 29 is located radially outward from pin nose sealing surface 28 , as indicated by the numeral 33 in FIG. 3 . If pin 12 is misaligned while stabbing into box 14 , guide surface 29 will contact internal thread 22 , protecting nose sealing surface 28 . The primary external seal of the connection 10 is formed near the box end 24 between an outwardly facing external sealing surface 32 on pin 12 and an inwardly facing external sealing surface 34 on box 14 . This primary external seal is another interference seal, formed by the metal-to-metal contact between surfaces 32 and 34 . Sealing surfaces 32 and 34 are located on a generally cylindrical portion of pin 12 and box 10 , but can also be tapered. As shown in FIG. 2, a lead-in or guide portion 35 joining box sealing surface 34 is tapered. A seal ring groove 36 is formed on pin 12 between the external thread 16 and the outwardly facing external sealing surface 32 . A thermoplastic seal ring 38 is located within seal ring groove 36 . Seal ring 38 acts as a back-up seal to the metal-to-metal external seal. Seal ring 38 seals against a bore surface 39 in box 14 that is lower than and separated from metal sealing surface 34 by a shoulder or step 37 . Alternately, seal ring 28 could be located above metal sealing surface 34 . The inner diameter of box 14 is greater at metal sealing surface 34 than at bore surface 39 . Sealing surface 34 on box 10 is protected from damaging contact during stabbing, as indicated by the misaligned stabbing occurring in FIGS. 4-6. A portion of pin threads 16 may contact the tapered guide surface 35 , but will not contact sealing surface 34 As shown in FIG. 5, the larger inner diameter of guide surface 35 as well as step 37 and smaller diameter bore portion 39 prevent contact. Similarly, pin nose sealing surface 28 is protected from damaging contact during stabbing, even if misaligned. As shown in FIG. 6, box threads 22 may contact guide surface 29 , but not sealing surface 28 because of its smaller outer diameter. Two stress relief grooves are formed on box 14 . The lower box stress relief groove 40 is located adjacent to the inwardly facing internal sealing surface 30 . The upper box stress relief groove 42 is located at the base of the threads 22 , spaced axially a short distance from groove 40 . These box stress relief grooves reduce the incidence of stress fractures of the box 14 , thereby improving the fatigue life of the connection 10 . Two stress relief grooves are formed on box 14 . The lower box stress relief groove 40 is located adjacent to the inwardly facing internal sealing surface 30 . The upper box stress relief groove 42 is located at the base of the threads 22 , spaced axially a short distance from groove 40 . These box stress relief grooves reduce the incidence of stress fractures of the box 14 , thereby improving the fatigue life of the connection 10 . Stress relief grooves 44 , 46 are separated by a conical band 41 . Upper stress relief groove 42 has a lesser axial extent than lower stress relief groove 44 , as well as a lesser radial depth. Sealing band 41 has a lesser axial width than lower stress relief groove 40 . Two stress relief grooves are also formed on pin 12 . The lower pin stress relief groove 44 is located at the base of threads 16 . The upper pin stress relief groove 46 is located adjacent to the dual angle torque shoulder 20 . As is shown in FIG. 1, thermoplastic seal ring 38 is located generally between the pin stress relief grooves 44 and 46 . The two pin stress relief grooves 44 and 46 reduce the incidence of stress fractures of the pin 12 , thereby improving the fatigue life of the connection 10 . The invention has significant advantages. The metal seals are protected from damage due to misalignment while stabbing the pin into the box. The make-up of the connection is self-aligning up to a certain degree of misalignment, such as three degrees. The dual angle torques shoulders preload the connection to stabilize the metal seals from cyclic loading. The long torque nose reduces torque needed for preload. While the invention has been shown or described in only one of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.	An offshore riser includes a plurality of tubular elements, each having a pin member on one end and a box member on the other end for connection with adjacent tubular elements. The pin member has an external thread which engages an internal thread on the box member of the adjacent tubular element. A dual angle torque shoulder locks the box end securely into place against the pin, preventing radial distention of the box end and maintaining bearing pressure between the external sealing surfaces. Also, stress relief grooves are located on the box member and on the pin member, to reduce the incidence of stress fractures, thereby improving the fatigue life of the connection.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION This invention is directed to a receptacle for the disposal of animal waste, and more particularly to a sanitary collapsible receptacle for disposing of animal wastes which includes an integrated scoop stick for directing excrement into the receptacle and an integrated carrying handle having an interlocking closure panel for ensuring the sanitary disposal of the excrement. The removal and disposal of animal wastes on streets and sidewalks has been a public and environmental problem for many years. Although this problem mainly exists in cities or other crowded areas, it is becoming an increasing concern in suburban and even rural areas. Many cities and towns now require pet owners to remove any waste produced by their pets or face the risk of receiving a fine or ticket. As a result, various devices have been designed for the pet owner for cleaning up the waste. One of the recurring problems with various devices for disposing of animal wastes is that these devices, if frequently used, become soiled and present a sanitary problem wherever they are stored. Therefore, it would be desirable to provide a device or product which is inexpensive to purchase, and which may be disposed of after use. SUMMARY OF THE INVENTION Generally speaking, in accordance with the invention, a receptacle for the disposal of animal wastes is provided. The receptacle includes a collapsible container having a selectively sealable opening for enabling access to the interior of the container and an integrated handle for carrying the container. The handle has a detachable scoop stick for gathering up animal waste and placing the waste in the container through the opening. Once the waste is in the container, a closure panel is positioned over the container's opening so that the animal waste is maintained in the receptacle. The animal waste disposal receptacle of the invention is made from a cardboard blank which is appropriately folded and manipulated in order to construct the receptacle. The blank includes a series of panels foldably connected to each other along common fold lines. The panels define the walls of the receptacle container When the blank is assembled. One end panel is connected to a handle panel which is formed with a detachable portion suitable for use as a scoop stick. The remaining portion of the handle panel may be used as a handle for carrying the receptacle during use. The other end panel of the receptacle includes a partially detachable door or closure element which enables selective access to the inside of the receptacle container. In use, the container closure element is opened so that waste or excrement may be placed inside the container. The container is then sealed by closing the closure element in order to maintain sanitary conditions. Since the receptacle of the invention is made of cardboard, the receptacle is simply disposed of after use. The receptacle of the invention is normally sold in a collapsed folded condition. The user first applies hand pressure on opposing ends of the collapsed receptacle in order to open the receptacle to its operating condition. In this configuration, the end panels thereof lock into place, forming a box shaped configuration. Then, the scoop stick is punched out from the handle panel. Thereafter, the closure element formed in one of the end panels is pulled out and folded down under the container so that it does not interfere with the operation thereof. Using the scoop stick, the user places the animal waste or excrement into the container. After finishing with the scoop stick, the scoop stick is then inserted into the container. Then, the closure element is placed over the opening into the container and locked into place. The receptacle is then carried to the nearest receptacle for disposal. Accordingly, it is an object of the invention to provide a receptacle for the disposal of animal wastes. It is another object of the invention to provide an animal waste receptacle having an integrated carrying handle, scoop stick and closure element. Yet a further object of the invention is to provide an animal waste receptacle which may be sold in a collapsed condition, but which is operable in an expanded condition. Still another object of the invention is to provide an animal waste receptacle which ensures the sanitary disposal of animal excrement. A further object of the invention is to provide a cardboard blank for constructing an animal waste receptacle. Yet another object of the invention is to provide an animal waste disposal receptacle which is both easy to use and disposable. Still other objects and advantages of the invention will in part be obvious and Will in part be apparent from the following description. The invention accordingly comprises the several steps and the relation of one or more such steps with respect to each of the others, and the article of manufacture possessing the features, properties and relation of elements which will be exemplified in the article hereinafter described, and the scope of the invention will be indicated in the claims. BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is made to the following description taken in connection with the accompanying drawings, in which: FIG. 1 is a top plan view of a blank from which an animal waste disposal receptacle in accordance with the invention may be constructed; FIG. 2 is a side elevational view of the animal waste disposal receptacle of the invention in a collapsed or packaged condition; FIG. 3 is a perspective view of the animal waste disposal receptacle of the invention shown in an open or expanded condition and illustrating the removal of the scoop stick from the handle panel; FIG. 4 is a partial perspective view of the end of the animal waste disposal receptacle shown in FIG. 3; FIG. 5 is a partial perspective view of the animal waste disposal receptacle of the invention showing the closure element in a closed condition; and FIG. 6 is a partial perspective view similar to that in FIG. 5, but showing the closure element in a closed condition, with the locking tab thereof in a locked position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, a cardboard unit blank 10 from which the animal waste disposal receptacle of the invention is constructed is shown. Cardboard blank 10 is made from a foldable flexible paper board material preferably having a high acid content for rapid biodegradability. Blank 10 includes a series of panels 12, 14, 16 and 18 foldably connected to each other along fold lines 22. Panel 12 has a flap attached thereto along fold line 23. In addition, panels 12, 14, 16 and 18 each include a first side flap 24a, 26a, 28a and 30a, respectively, and a second side flap 24b, 26b, 28b and 30b, respectively. Flaps 24a and 24b include sections 34a and 34b, while flaps 28a and 28b also include sections 35a and 35b. All of these flaps and sections are used for constructing the waste disposal receptacle of the invention from cardboard blank 10, as described below. Panel 18 is foldably connected or attached to a handle panel 42, as shown in FIG. 1. Handle panel 42 includes a scoop stick cut-out 44 defined by perforated line 45. Panel 12 also includes an end flap 20 and both are formed with a closure element cut-out 46, as best shown in FIGS. 1 and 2. Cut-out 46 is defined by perforated lines or edges 49a, 49b and 51, and is formed with a locking tab 48. Closure element cut-out 46 is pivotally swingable along fold line 22 for selectively opening and closing the opening formed by cut-out 46. In order to construct the waste disposal receptacle of the invention from blank 10, sections 34a and 34b of closure flap 24a and 24b are placed below and attached to the undersides of closure flaps 26a and 26b. Similarly, sections 35a and 35b of closure flaps 28a and 28b are disposed below and attached to the undersides of closure flaps 30a and 30b. Attachment may be by gluing, stapling or another conventional mechanism. As a result, panels 12 and 18 are now folded inwardly and upwardly. Then, the underside of end flap 20 is attached to the top side of flap 18 adjacent to fold line 22 between panel 18 and panel 42 in order to form a collapsed folded receptacle 11, as best shown in FIG. 2. Receptacle 11 in FIG. 2 is in a collapsed condition, as previously described, and is suitable for packaging, display and sale purposes. Receptacle 11 may be folded in half along fold line 22 for carrying in a shirt or pants pocket prior to use. Receptacle 11 may include printed matter thereon, including applicable trademarks and directions for use. Preferably, the printed matter is created by soybean based inks, which have a minimal effect on the ecosystem. In order to erect receptacle 11 so that it is operable for the user, pressure is exerted by the user against the diagonally opposite corners thereof so that closure flaps 24a, 26a, 28a and 30a, and closure flaps 24b, 26b, 28b and 30b lock into position (see FIG. 3). As a result, receptacle 11 now has a generally rectangular box configuration, with handle panel 4 extending upwardly therefrom. In operation of receptacle 11, the user must remove scoop stick cut-out 44 from handle panel 42. This is achieved by applying pressure on the scoop stick cut-out 44 to release cut-out 44 from panel 42, as shown in FIG. 3. Scoop stick 44 is now ready for pushing and/or scooping animal feces and excrement. Handle panel 42 now includes a handle opening and may be grabbed by the user for carrying receptacle 11. To operate animal waste disposal receptacle 11, it is also necessary to form an opening therein. This is achieved by first pushing in, and then pulling out closure element 46 so that a window is formed in receptacle 11 (see FIG. 3). Closure element 46 is fully extended below receptacle 11, yet is maintained attached thereto along fold line 22. After closure element 46 has been fully extended, receptacle 11 is now ready for use. Using scoop stick 44, the user may pick up the animal excrement and place it into receptacle 11 through the Window formed therein. Alternatively, receptacle 11 is placed on the ground and scoop stick 44 is used to push the animal excrement into receptacle 11. Once the inside of receptacle 11 has been filled with the animal excrement, scoop stick 44 is inserted therein. Then closure element 46 is pivoted back over the window of receptacle 11 and locking tab 48 is pulled through slot 52 (see FIGS. 5 and 6) in order to securely lock receptacle 11 for subsequent disposal. As a result, the sanitary disposal of animal feces and excrement is maintained. It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above method and in the articles set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in this description is shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.	A receptacle for the disposal of animal wastes is provided. The receptacle includes a collapsible container having a selectively sealable opening for enabling access to the interior of the container and an integrated handle for carrying the container. The handle has a detachable scoop stick for gathering up animal waste and placing the wastes in the container through the opening. Once wastes are in the container, a closure panel is positioned over the opening so that the animal waste is maintained in the receptacle.
You are an expert at summarizing long articles. Proceed to summarize the following text: RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60/946,614, entitled DECK RAILING COUNTERTOP SYSTEM, filed Jun. 27, 2007, hereby fully incorporated by reference herein. FIELD OF THE INVENTION [0002] The invention relates generally to outdoor deck accessories, and more particularly, to a deck railing countertop system. BACKGROUND OF THE INVENTION [0003] Many residential structures such as single-family homes, townhouses, apartment buildings, and other such residences, include an attached outdoor deck. A basic deck built to typical local standards minimally includes a deck platform and a railing system. Most deck platforms include a series of adjacent treads, or decking, with an understructure to support the platform. A typical railing system includes a series of support posts attached to the deck platform, a hand rail, and supporting intermediate posts. The railing system safely keeps occupants and belongings from falling off the deck platform. [0004] For many homeowners, the outdoor space provided by a deck becomes an integral part of their home, and they often place items such as tables, chairs, grills, decorative items, and so on, onto the deck platform for their use and enjoyment. All too often, though, the usable area of a deck platform may not comfortably accommodate multiple pieces of furniture, let alone leave room for social gatherings. The result may be that a homeowner compromises by limiting the number of items placed onto the deck platform. This may mean that space-consuming tables may be sacrificed in order to make room for higher priority items such as chairs or grills. [0005] If a homeowner desires table-like surfaces, options include building a larger deck, bringing a table onto, and off of the deck platform as needed, and so on. For many, the option of a larger deck may be expensive, impractical, or impossible. Regarding the use of a temporary table, lack of storage space and general inconvenience make this a non-ideal solution. Furthermore, tables placed upon a deck platform may be blown about during storms, causing damage to the table itself, the deck, or other items nearby. Therefore, a need exists for a system or apparatus that provides table-like surfaces for a deck, without sacrificing deck platform space. SUMMARY OF THE INVENTION [0006] In one embodiment, the present invention provides a deck rail countertop system that attaches to a deck railing system. The countertop system includes a mounting bracket, countertop, and fasteners. In one embodiment, the mounting bracket is a T-shaped bracket that attaches to the front side of a deck support post. In another embodiments, the T-shaped bracket attaches to the back side of a deck support post. The countertop provides a table-like surface and includes a recess and matching slot for receiving the top portion of the mounting bracket. [0007] In another embodiment, the present invention provides a deck rail countertop system that attaches to a deck railing system, and includes a mounting bracket that fits over the top of a support post. In this embodiment, a countertop rests on a support portion of the mounting bracket and is secured to the bracket via fasteners. The mounting bracket is secured to the support post using fasteners. In a related embodiment, the mounting bracket is an E-shaped bracket that fits over a hand rail, rather than a post, and supports a countertop via a support portion on the bracket. [0008] In yet another embodiment, the present invention provides a deck rail countertop system that attaches to a deck railing system via a snap-lock mounting bracket. The snap-lock mounting bracket includes a top bracket with snap-lock tabs that fit into recesses located in the sides of the bottom bracket. The bottom bracket is attached directly to a support post or multiple intermediate posts. In one embodiment, the top bracket includes a boss that fits into a recess in the countertop. The top bracket may be pressed into the countertop to create a press fit, or friction fit, securely holding the assembly together. [0009] Other embodiments include a variety of countertop mounting brackets, such as a T-shaped mounting bracket, an E-shaped hand rail mounting bracket, and a snap-lock mounting bracket. [0010] In an embodiment, the present invention may also include a method for connecting a countertop to a deck railing system that includes attaching a mounting bracket to a support post, sliding a countertop onto a bracket top portion, and securing the countertop to the bracket. [0011] Accordingly, a deck rail countertop system adapted to attach to a railing of a deck or balcony may generally include a plurality of mounting brackets, each mounting bracket comprising a deck railing interface portion and a countertop interface portion, the deck railing interface portion defining structure for receiving and coupling to a component of the railing, and an elongate countertop. The countertop presents a top surface, a bottom surface and a length dimension. The countertop and countertop interface portion of each mounting bracket have cooperating structure for coupling the mounting brackets to the bottom surface of the countertop at a plurality of spaced apart locations along the length dimension of the countertop. [0012] In an embodiment, the deck railing interface portion of each mounting bracket includes an over-post portion defining a cavity, the cavity dimensioned so as to receive an end of a post of the railing therein. [0013] In an embodiment, the deck railing interface portion includes a pair of horizontally oriented members, the members vertically spaced apart so as to define a slot therebetween adapted to receive a horizontal member of the railing. [0014] In an embodiment, the deck railing interface portion includes a first body portion and the countertop interface portion includes a second body portion separate from the first body portion, the first body portion and second body portion each having cooperating structure for removably operably coupling the first body portion and the second body portion. [0015] In an embodiment, the cooperating structure for removably coupling the first body portion and the second body portion includes at least one selectively deflectable tab on one of the first body portion or the second body portion, and structure for receiving the selectively deflectable tab on the other of the first body portion or the second body portion. The structure for receiving the selectively deflectable tab may be an aperture. [0016] In an embodiment, the cooperating structure for coupling the mounting brackets to the bottom surface of the countertop includes an elongate slot defined in the bottom surface of the countertop, the elongate slot oriented along the length dimension of the countertop, and a t-shaped portion of the countertop interface portion adapted to be slidably received in the elongate slot. [0017] In an embodiment, the cooperating structure for coupling the mounting brackets to the bottom surface of the countertop includes a plurality of recess arrays, each recess array comprising a plurality of recesses, the recess arrays defined at spaced apart locations in the bottom surface of the countertop, and each countertop interface portion includes a plurality of apertures corresponding to the recesses of the recess array, the apertures of the mounting bracket disposed to be registerable with the recesses of each of the plurality of recess arrays to receive fasteners for fastening the mounting bracket to the countertop. [0018] In further embodiments, a deck system according to the invention includes a deck, a railing operably coupled with the deck, the railing comprising a plurality of upright posts and a horizontal rail operably coupling the upright posts, and a deck rail countertop system. The deck rail countertop system includes a plurality of mounting brackets, each mounting bracket comprising a deck railing interface portion and a countertop interface portion, the deck railing interface portion operably coupled to the railing, and an elongate countertop presenting a top surface, a bottom surface and a length dimension, the countertop and countertop interface portion of each mounting bracket having cooperating structure for coupling the mounting brackets to the bottom surface of the countertop at a plurality of spaced apart locations along the length dimension of the countertop. [0019] In other embodiments, a method of providing a deck rail countertop system adapted to attach to a railing of a deck or balcony includes providing a plurality of mounting brackets, each mounting bracket including a deck railing interface portion and a countertop interface portion, the deck railing interface portion defining structure for receiving and coupling to a component of the railing, providing an elongate countertop presenting a top surface, a bottom surface and a length dimension, the countertop and countertop interface portion of each mounting bracket having cooperating structure for coupling the mounting brackets to the bottom surface of the countertop at a plurality of spaced apart locations along the length dimension of the countertop, and providing instructions for attaching the mounting brackets to the railing and for attaching the countertop to the mounting brackets. [0020] In an embodiment, the method may further include packaging the plurality of mounting brackets and the countertop together in a kit. [0021] In an embodiment, the method may further include packaging the instructions with the kit. [0022] In an embodiment, the method may further include recording the instructions in a tangible medium. BRIEF DESCRIPTION OF THE DRAWINGS [0023] The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the following drawings, in which: [0024] FIG. 1 is a side view of one embodiment of a front-mount deck rail countertop system attached to a deck railing system; [0025] FIG. 2 is a perspective view of one embodiment of a front-post mounting bracket; [0026] FIG. 3 is an exploded perspective view of one embodiment of a front-mount deck rail countertop system; [0027] FIG. 4 is a perspective view of one embodiment of a front-mount deck rail countertop system attached to a deck railing system; [0028] FIG. 5 is a side view of one embodiment of a rear-mount deck rail countertop system attached to a deck railing system; [0029] FIG. 6 is a front perspective view of one embodiment of an over-post mounting bracket and deck railing system; [0030] FIG. 7 is a rear perspective view of one embodiment of a hand-rail mounting bracket as attached to a deck railing system hand rail; [0031] FIG. 8 is an exploded perspective view of one embodiment of a snap-lock mounting bracket; [0032] FIG. 9 is a perspective view of one embodiment of a top bracket of a snap-lock mounting bracket; [0033] FIG. 10 is a perspective view of one embodiment of an assembled snap-lock mounting bracket; [0034] FIG. 11 is a perspective view of one embodiment of a deck railing countertop system attached to a deck railing system by mounting to a support post and a pair of intermediate posts; and [0035] FIG. 12 is another perspective view of one embodiment of a deck railing countertop system attached to a deck railing system by mounting to a support post and a pair of intermediate posts. [0036] While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION [0037] Referring to FIG. 1 , a front-mount embodiment of the deck-railing countertop system 20 is connected to a deck railing system 22 of deck 24 . In this embodiment, deck-railing countertop system 20 generally includes front-post mounting bracket 26 , countertop 28 , and fasteners 30 (depicted in FIG. 4 ). Deck railing system 22 includes posts 32 , hand rail 34 , and intermediate posts 36 . [0038] Referring now to FIG. 2 , in one embodiment, front-post mounting bracket 26 is a generally “T” shaped bracket, and includes a body portion 38 and head portion 40 . Front-post mounting bracket 26 and countertop 28 may be made of any of a variety of materials including wood, plastic, aluminum, steel, fiberglass, composite materials, and other materials suitable for outdoor use. [0039] Head portion 40 generally includes front extension 42 with front end 44 , rear extension 46 with rear end 48 , top surface 50 , front bottom surface 52 , rear bottom surface 54 , and a plurality of optional holes 56 . The lengths of front extension 42 and rear extension 46 may be varied to accommodate the dimensions of countertop 28 , and to adjust the position of countertop 28 in relation to deck 24 and hand rail 34 . For example, in the embodiment depicted in FIG. 1 , front extension 42 is slightly longer than rear extension 46 such that rear end 48 is substantially in the same plane as the outside of post 32 . As depicted in FIG. 2 , rear extension 46 may be slightly longer than front extension 42 . [0040] Still referring to FIG. 2 , front end 44 includes a front surface 58 , while rear end 48 includes a rear surface 60 . In one embodiment, horizontal portion 40 is generally rectangular in shape and connected to, or integral with, body portion 38 . Front surface 58 and rear surface 60 may be curved as depicted, but in other embodiments, may be flat, depending on countertop 28 characteristics. In one embodiment, holes 56 extend through head portion 40 and are located at both front end 44 and rear end 48 . [0041] Body portion 38 includes a top end 62 , bottom end 64 , bottom side 66 , rear side 68 , a left side 70 , right side 72 , left-front edge 74 , right-front edge 76 , recess 78 , and width W. In one embodiment, rear side 68 and bottom side 66 are generally flat, while left-front edge 74 and right-front edge 76 are curved. Although not depicted, in one embodiment, rear side 68 includes mounting holes 80 . Recess 78 is substantially defined by bottom side 66 , rear side 68 , left side 70 , right side 72 , and head portion 40 . [0042] Referring now to FIG. 3 , countertop 28 generally includes a top side 80 , bottom side 82 , rear side 84 , front side 86 , recess 88 , slot 90 , and inner surface 92 . Countertop 28 may also include an optional lip 94 located at the corner of top side 80 and rear side 84 . In one embodiment, countertop 28 is a substantially rectangular shape, though countertop 28 may be square, curved, or otherwise shaped. In one embodiment, front end 86 forms an obtuse angle with top side 80 and has rounded edges. The shape of recess 88 generally matches the shape of head portion 40 as viewed from the side, such that head portion 40 may be inserted into recess 88 . As such, the width of slot 90 is slightly larger than width W. In one embodiment, slot 90 extends longitudinally along the entire length L of countertop 28 , in other embodiments, slot 90 extends longitudinally only along a portion of length L. [0043] Still referring to FIG. 3 , in one embodiment, mounting bracket 26 is adapted to fit into recess 88 such that top surface 50 , front bottom surface 52 , rear bottom surface 54 , front surface 58 and rear surface 60 , contact countertop 28 inside surface 92 . In some embodiments, not all top portion 40 defined surfaces will contact inside surface 92 . [0044] Referring now to FIG. 4 , deck countertop system 20 may be mounted to a front side of deck railing system 22 . In the depicted embodiment, a pair of front-post mounting brackets 26 are inserted into countertop 28 . Each front-post mounting bracket 26 is connected to a post 32 using fasteners 30 . In one embodiment, fasteners 30 are screws, and a screwdriver or other tool is inserted into recess 78 and used to screw fasteners 30 through holes or slots (not shown) in brackets 26 , thereby securing mounting brackets 26 into posts 32 . In the embodiment depicted in FIG. 4 , rear sides 68 of front-post mounting brackets 26 contact font sides of posts 32 , and mounting brackets 26 are flush with each end of countertop 28 . In other embodiments, a length of countertop 28 may be longer than the distance between posts 32 , and may also utilize more than two mounting brackets 26 . [0045] In one embodiment, rear side 84 of countertop 28 extends rearwardly over posts 32 and hand rail 34 . Front side 86 is located above the treads of deck 24 . Because countertop 28 is supported by mounting brackets 26 attached to posts 32 , and not supported by a separate support structure resting on deck 24 , the entire area of deck 24 remains open for use. [0046] Fasteners 30 may also be similarly used to secure countertop 28 to mounting brackets 26 via holes 56 . In other embodiments, fasteners 30 are not used so that countertop 28 may be more easily removed from brackets 26 . In some embodiments, countertop 28 may include lip 94 that prevents items placed on countertop 28 from easily falling off the rear side of the countertop. [0047] Referring now to FIG. 5 , deck railing countertop system 20 may be of a rear-post mount type. In the rear-mount system as depicted in FIG. 5 , rear-post mounting bracket 94 is substantially similar to previously described front-post mounting bracket 26 , and countertop 96 is substantially similar to countertop 28 . In this embodiment, front extension 42 is longer than rear extension 46 , and slot 90 is located closer to countertop 94 rear side 84 . This causes countertop 96 to extend further over deck 24 , as opposed to off the rear of deck 24 . [0048] As depicted, in this rear-mount embodiment, a front side 98 of mounting bracket 94 abuts post 32 , and is secured to the post with fasteners 30 similar to the manner previously described. Furthermore, rear-post mounting bracket 94 is positioned on post 32 such that an air gap is created between countertop 96 and post 32 . This enables easy placement of countertop 96 onto mounting bracket 94 . [0049] Referring now to FIG. 6 , in another embodiment, deck railing countertop system 100 generally includes an over-post mounting bracket 102 , countertop 104 , and fasteners 30 . In this embodiment, mounting bracket 102 is an L-shaped bracket and includes an over-post portion 106 , support extension 108 with top surface 110 , post holes 112 , and extension holes 114 . Over-post portion 106 is generally hollow, or recessed, such that it fits over post 32 . In one embodiment, the over-post recess is dimensioned to fit over a standard nominal 4 ″× 4 ″ post 32 . In other embodiments, over-post portion 106 is adapted to fit over posts 32 of other dimensions and shapes. After being placed over post 32 , mounting bracket 102 may be secured to post 32 by inserting fasteners 30 through holes 112 and into post 32 . In some embodiments, mounting bracket 102 may include more than one support extension 108 , and may be rotatable about post 32 . [0050] Support portion 108 extends outwardly and away from over-post portion 106 , and in one embodiment forms a 90 degree angle with over-post portion 106 . Top surface 110 of support portion 108 is substantially flat such that countertop 104 may be placed onto, and supported by, top surface 110 . Fasteners 30 may be inserted through holes 114 and into countertop 104 in order to secure the countertop to support bracket 102 . Predrilled arrays of recesses (not depicted) may be provided in the bottom surface 118 of countertop 104 . In each array, the recesses are arranged in the same pattern and spacing as extension holes 114 . The arrays can be spaced apart at selected locations along the length of countertop 104 corresponding, for example, to various standard spacings of posts 32 . Upon installation of the system, the support brackets 102 can be secured to the posts 32 , and the countertop 104 placed over the support brackets with extension holes 114 of each support bracket 102 registered with the recesses of one of the recess arrays. Fasteners can then be driven through extension holes 114 and into the recesses to secure the countertop to the support bracket. Advantageously, these pre-defined recess arrays eliminate the need to drill countertop 104 in order to accommodate fasteners. [0051] In this embodiment, countertop 104 has a substantially flat, planar bottom surface 118 and top surface 116 . As described previously with respect to countertop 28 , countertop 104 similarly may be made of wood, plastic, fiberglass, aluminum, stainless steel, stone, or other similar materials suitable for outdoor use. As depicted in FIG. 6 , countertop 104 may be substantially rectangular, but in other embodiments, may take other shapes in accordance with the particular functional and aesthetic features of deck 24 . [0052] Referring now to FIG. 7 , in another embodiment of deck railing countertop system 100 , the mounting bracket is an E-shaped mounting bracket 120 that connects to hand rail 34 . In this embodiment, mounting bracket 120 includes support extension 108 , vertical portion 122 , top hand rail extension 124 , bottom hand rail extension 126 , recess 128 , recess face 130 , and holes 132 . [0053] In one embodiment, support extension 108 , top hand rail extension 124 and bottom hand rail extension 126 are connected, or integral with, vertical portion 122 . These extensions may be positioned at a substantially ninety-degree angle with vertical portion 122 , depending on the particular hand rail 34 and desired pitch of countertop 104 . As depicted in FIG. 7 , in one embodiment, support extension 108 is longer than, or extends outwardly further than, either top hand rail extension 124 or bottom hand rail extension 126 in order to adequately support countertop 104 . Top hand rail extension 124 is located atop hand rail 34 , while bottom hand rail extension 126 is located beneath hand rail 34 . In this embodiment, the distance between extensions 124 and 126 are such that only a minimal air gap between bottom hand rail extension 126 and hand rail 34 exists when extension 124 rests on hand rail 34 . [0054] Recess 128 and recess face 130 are located opposite extensions 108 , 124 , and 126 , on the rear side of mounting bracket 120 . Recess face 130 may include one or more holes 132 located adjacent hand rail 34 . [0055] When assembled, mounting bracket 120 rests on, and is attached to hand rail 34 . Top hand rail extension 124 rests on the top side of hand rail 34 , and may be attached to hand rail 34 by inserting fasteners 30 (not shown in FIG. 7 ) through holes 134 and 132 and into hand rail 34 . At the same time, the two extensions 124 and 126 , along with vertical portion 122 , essentially form a clamp over hand rail 34 , substantially preventing bracket 120 from rotating about an axis along the length of hand rail 34 . Countertop 104 is attached to support extension 108 , resting on surface 110 , by way of fasteners 30 and holes 114 . [0056] Referring now to FIGS. 8 and 9 , in another embodiment, deck railing countertop system 100 utilizes a snap-lock mounting bracket 140 that includes a top bracket 142 and a bottom bracket 144 . Top bracket 142 generally includes a top boss 146 , top surface 148 , left side 150 , right side 152 , outer side 154 , inner side 156 , bottom side 157 , one or more snap-lock tabs 158 , channel 160 , holes 162 and holes 164 . [0057] Top boss 146 projects above top surface 148 and includes a boss surface 147 , and may also include multiple recesses 166 . In one embodiment, a countertop 104 includes a recess or receptacle adapted to receive top boss 146 , and top bracket 142 may be pressed into the recess of countertop 104 . In another embodiment, countertop 104 does not include a recess, and is located on top of top boss 146 , resting on boss surface 147 . Fasteners may be inserted through holes 164 and into countertop 104 to secure the countertop to top bracket 142 . Holes 162 in bottom side 157 allow a screwdriver to be inserted into top bracket 142 to facilitate the fastening process. [0058] Left side 150 and right side 154 may include a snap-lock tab 158 . The bottom of each snap-lock tab 158 is connected to its respective side, and normally projects upwards and slightly away from top bracket 142 at its top side. Each snap-lock tab 158 is adapted to flex inward towards top bracket 142 when pressure applied to an outside surface of the tab. [0059] As depicted in the embodiment of FIG. 9 , channel 160 is formed from a U-shaped center structure 168 projecting upwards from bottom side 157 of bottom bracket 142 , providing structural support. [0060] Referring again to FIG. 8 , bottom bracket 144 includes left side 170 , right side 172 , inner side 174 , and holes 184 . Left side 170 and right sided 172 include left-side opening 176 and right-side opening 178 . In one embodiment, inner side 174 is substantially square and includes holes 180 . As depicted, left side 170 and right side 172 each form a right angle with inner side 174 . In one embodiment, openings 176 and 178 are rectangularly shaped and adapted to receive snap-lock tabs 158 of top bracket 142 . Bottom bracket 144 may be attached to any side of a post 32 using fasteners inserted through holes 180 . [0061] Referring now to FIG. 10 , top bracket 142 fits into bottom bracket 144 to form snap-lock mounting bracket 140 . Sliding top bracket 142 downwards into bottom bracket 144 initially causes snap-lock tabs 158 to flex inwards. When snap-lock tabs 158 fully align with openings 176 and 178 , the forces against tabs 158 are removed, and tabs 158 spring back to their at-rest position, thereby locking top bracket 142 into bottom bracket 144 . [0062] Referring now to FIGS. 11 and 12 , snap lock mounting brackets 140 may support a countertop 104 and be attached to either a support post 32 or intermediate posts 36 . As depicted in FIG. 12 , one snap-lock mounting bracket 140 is secured directly to a rear side of a support post 32 . Also depicted is a second snap-lock mounting bracket 140 attached to a pair of intermediate posts 36 . In this embodiment, an intermediate post bracket 182 is secured to the intermediate posts 36 , and the second snap-lock mounting bracket 140 is secured to the intermediate post bracket 182 . In other embodiments, all snap-lock mounting brackets may be attached directly to support posts 32 , or may all be attached to intermediate posts 36 . [0063] In further embodiments, the invention may include component kits generally including one or more brackets and a countertop supplied with instructions for installing the brackets and 6 countertop on a new or existing deck. The components may be pre-packaged or may be separately displayed so as to enable a user to select the desired type and number of components needed. The instructions may detail steps of installing the brackets and countertop to form a deck railing countertop as described above in exemplary embodiments. The instructions may be embodied in paper form or in other media such as computer readable media (CD, DVD, or internet delivered e-file), video, or audio. [0064] In further embodiments, the invention may include methods of delivering components and installation instructions. For example, components may be provided in pre-packaged form, and instructions as described above may be provided along with the package of components. In another example, the instructions may be made available separately from the components and the user may be instructed as to how to obtain the instructions from a separate source such as from an internet website. [0065] The embodiments above are intended to be illustrative and not limiting. Additional embodiments are encompassed within the scope of the claims. Although the present invention has been described with reference to particular embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. For purposes of interpreting the claims for the present invention, it is expressly intended that the provisions of Section 112, sixth paragraph of 35 U.S.C. are not to be invoked unless the specific terms “means for” or “step for” are recited in a claim.	A deck rail countertop system adapted to attach to a railing of a deck or balcony. The system includes a plurality of mounting brackets and a countertop. Each mounting bracket includes a deck railing interface portion and a countertop interface portion. The deck railing interface portion defines structure for receiving and coupling to a component of the railing. The countertop and countertop interface portion of each mounting bracket have cooperating structure for coupling the mounting brackets to the bottom surface of the countertop at a plurality of spaced apart locations along the length of the countertop.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to ground anchors, and more specifically to driven pivoting ground anchors. 2. General Background Ground anchors, or earth anchors, of the driven and pivoting or tilting type are well known and generally include a main body portion having a leading edge adapted to be driven into the ground, a trailing edge including an outturned lip and a cable or rod or guide wire attachment point intermediate the leading and trailing edges generally positioned from about the midpoint of the overall length of the anchor or towards the trailing edge so that upon exertion of the force on the cable or attached rod or guide wire, after insertion of the anchor into the ground, the trailing edge's outturned lip will bite into the earth, causing the anchor to rotate or pivot to a locked position generally at a right angle to the withdrawal force. Widely currently used driven pivoting anchors of the type described are available from the assignee of this application under its Duckbill trademark and generally employ a somewhat cylindrical main body portion having an attachment point intermediate its ends and having at its forward end a plurality of forwardly extending guiding plane surfaces which terminate in chiseled edges. The cylindrical body shaped member, at its trailing end, has a bore extending into the body of the cylindrical member for receipt of a drive rod for driving the anchor into the earth and is provided with an outturned lip on a side of the cylindrical body portion opposite the side having the cable or guide wire attachment point. Such anchors are shown, for example, in U.S. Pat. Nos. 4,044,513 and 4,096,673, both of which are assigned to the assignee of this application. Improvements of such anchors are well known and include, for example, applicant's pending Design application No. 29/270,187, now Pat. No. D572546 issued Jul. 8, 2008 and U.S. Utility application Ser. No. 11/803,138 filed May 14, 2007, now U.S. Pat. No. 7,534,073 issued May 19, 2009. Other variants of such anchors are sold, for example, by Foresight Products, LLC under trademarks Manta Ray and Stingray and employ extensive side projecting wings that extend backwardly and outwardly from the leading edges to a greater or lesser degree and provide greater resistance to withdrawal of the anchor after the anchor has been driven into the ground and rotated to the point where the wings lie substantially normal to the tension direction of the cable. While such anchors, both of the wingless, small-winged and large wing design, have found successful utility in many applications, including use in connection with revetment and soil retaining mats. However, the chiseled or sharpened leading edges which facilitate penetration into the ground can, in certain instances, cause damage to certain types of soil retaining mats which are commonly used in turf reinforcement and ground stabilization. Such mats, often known as High Performance Turf Reinforcement Mat (HPTRM) of the type available under the mark Pyramat from Propex, Inc. or of the type shown, for example, in U.S. Pat. No. 5,616,399 entitled “Geotextile Fabric Woven or a Honeycomb Weave Pattern and having a Cuspated Profile after Heating,” may consist of individual strands essentially woven together and formed or fused to provide the mat. The strands are generally manufactured of plastics material. Other fabric-like woven mats utilizing similar or different materials are also known, as are non-woven mats. Where it is desired to anchor such mats to the underlying soil, the use of the previously known driven pivoting anchors can cause damage to the mat, particularly since the chiseled or sharpened leading edges will have a tendency to cut through the material of the mat, thereby weakening the mat. It would therefore be an advance in the anchoring field to provide an anchor suitable for use with such turf reinforcement mats which could be driven through the mat with a reduced likelihood of damage to the mat. SUMMARY OF THE INVENTION The above advances are provided by the current invention by utilizing a driven pivotal anchor where the leading end is provided with a curved or rounded non-sharp leading end and flattened guiding plane edges. In an embodiment of the invention a plurality of ribs or guiding plane leading edges extend forwardly of the generally cylindrical main body portion of the anchor with each edge being either blunt or rounded and with each edge converging to a common leading end which is generally rounded. In an embodiment of the invention the leading edges projecting forward of the generally radial cylindrical main body portion are circumferentially spaced from one another and formed as the outside surface of ribs or guiding planes with the edges formed blunted or rounded and which converge to a common leading front end, the leading front end being rounded. In an embodiment of the invention the generally cylindrical body member has four leading edges formed as orthogonal ribs or planes extending forwardly of the generally cylindrical body portion and tapering to a common leading end which is rounded generally in a partial spherical configuration. It is therefore an object of the invention to provide a ground anchor having improved utility for use with mat structures having leading edge surfaces having a reduced tendency to damage the mat during driving of the anchor through the mat structure. It is a further and more specific object of this invention to provide a driven pivoting anchor having a rounded or ball-like leading end. These and other objects will be apparent to those of ordinary skill in the art from a description of the illustrated preferred embodiment, being understood that this is only one such embodiment of this invention and that many variations of shape and dimension are within the scope of this invention. Specifically the generally overall shape of the anchor, the shape of the main central body portion, the shape and extent of the side wings and the number of leading edges or ribs are all modifiable as is generally known to those of ordinary skill in the art and practice in differing commercially available embodiments of driven pivoting anchors. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the anchor of this invention. FIG. 2 is a cross sectional view of the anchor of this invention taken along the lines 2 - 2 of FIG. 1 . FIG. 3 is a cross sectional view of the anchor taken along the lines 3 - 3 of FIG. 1 . FIG. 4 is a side schematic view of the driving of the anchor of this invention through a HPTRM mat and into the ground. FIG. 5 is an enlarged perspective view of the undersurface of the mat illustrating how the nose of the anchor passes through the stranding of the mat. FIG. 6 illustrates the locked position of the anchor after rotation from the driving position to the locked position. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates a ground or earth anchor 10 of the type often referred to as a driven and rotating or pivoting anchor in that the anchor is driven into the ground by force and after having being driven to the desired depth, a cable or rod attachment member attached to the anchor is pulled in a direction to withdrawal the anchor from the ground. Because of the design of the anchor and the position of the attachment of the cable or pulling rod to the anchor, the pulling of the anchor by the attachment member causes the anchor to undergo a pivoting or rotation in the ground towards a final position in which the longitudinal axis of the anchor is positioned more towards a position normal to the pulling cable or rod as shown in FIG. 6 . Such anchors often include a main body section 11 , which may be generally cylindrically formed (other shapes are known in the art, including rectangular and oval), a leading edge 12 , a trailing edge 13 , a raised section 14 having means 2 for attachment of a cable, shackle, pivot bolt or the like, which may comprise or be attached to the withdrawing force member which causes the anchor to rotate or pivot from its driven position to its' final locked position. As shown in FIG. 1 , oftentimes the attachment means 2 is merely an opening through a raised rib 16 on one side of the main body portion 11 . The opening may receive a looped crimped cable end 40 or a shackle bracket or the like. Alternative structures are well known such as where the rib-like structure includes attachment means for receipt of the end of a T-shaped rod or other type of swiveling device. An open bore 17 in the trailing edge extends into the main body portion 11 terminating in a blind end 28 which may, as shown in FIGS. 2 and 3 , be flat or which may be rounded or otherwise configured. A driving rod 41 extends into the bore 17 and is used to drive the anchor into the earth. The driving rod may simply be impacted by a hammer for smaller anchors or may be driven by a pneumatic or hydraulic reciprocating power driver for larger anchors. In the embodiment illustrated the main body portion is generally cylindrical and terminates at a leading end 11 a of the main body portion in a frustoconical section 11 b and four equally-distanced spaced ribs of which three, 15 , 17 , and 19 can be seen in FIG. 1 , the fourth being on the bottom opposite the rib 19 . Each of the ribs has an outer edge surface 18 and the rib surfaces 18 converge towards the leading end 12 . The outer edges 18 may be flat or blunt as shown in FIG. 1 or may be outwardly curved but preferably are not provided with a sharp edge. The ribs 15 , 16 , 17 may have different shapes. The ribs 15 and 17 extending back behind the frustoconical portion 11 b and converge into side wings 20 and 21 , which also preferably have rounded or non-sharp outer edges 22 . The rib 19 has its edge 18 extending back to the leading end of the generally conical section 11 a and blending into the top edge surface 14 of the raised rib 16 . The four ribs, in this embodiment, converge together to a rounded nose 25 at the end 12 . Although different shapes can be provided for the nose, a part spherical or partial ball shape is preferred, although a parabolic shape or some other curvature is acceptable, it being important that the leading end 12 not be provided with a sharp edge. By providing a rounded leading edge 12 , the anchor is able to be driven through the mat 60 with minimal damage to the stranding of the mat and, in fact, for smaller anchors without severing any of the strands of the mat as the ball-like nose 25 pushes its way between the strands and non-sharp, rounded or blunt edges 18 force the strands apart as the main body portion of the anchor begins to pierce through the mat. The side 31 of the anchor opposite the raised rib 16 is provided at its trailing edge 32 with an outturned lip 33 to facilitate pivoting during drawback, as is well known in the art. In use the mat schematically shown at 60 is placed in position on the surface to be retained or secured and the ball-like nose of the anchor is placed against the mat surface and is then begun to be driven through the mat. As the ball-like nose, or rounded nose, enters the structure of the mat it will cause the strands of the mat to be pushed aside (see FIG. 5 ). As the anchor is driven further into the mat, the degree by which the strands are pushed aside will increase to allow the anchor to pass through the mat. In many instances utilizing normally stranded mats and standard smaller sized anchors equipped with the rounded or ball-like nose leading edge, the entire anchor can be pushed through the mat without breaking the strands of the mat. In other instances when slightly larger anchors are used one or more of the strands may be stretched beyond its limit and separate, but damage to the mat is minimal compared to the use of sharper or chiseled or leading edges or sharper edges extending backwardly from a leading point. While the use of blunted, rounded non-sharpened nose portions and leading side edges on the ribs and along the body may increase the resistance to driving of the anchor into the ground, when such anchors are used for soil erosion or soil stabilization, they are most often used in connection with looser or less resistant soil conditions such that the disadvantage, which may rise from an increase in resistance to driving in comparison to chiseled edged or sharpened edged anchors is minimized. After the anchor is driven into the ground it is rotated to its locked position by pulling upwardly on the attachment member. Thereafter the mat is secured to the attachment member by any suitable securing structure 63 . It will therefore be understood from the above that this invention improve upon the prior art driven pivoting anchors by providing an intentionally rounded non-sharp leading nose or leading end which can be pushed through a woven or non-woven retaining mat with minimal damage to the mat. Persons of ordinary skill in the art will understand that this invention may be practiced in embodiments other than that illustrated. It is not intended that this invention be limited to the particular anchor shape shown.	An earth anchor of the pivoting type having an essentially cylindrical body, a blind bore extending thereinto from a trailing axial end of the cylindrical body and a leading edge projecting from a leading end of the body, the leading edge being formed as a rounded surface adapted for penetration through reinforcement paths while minimizing severing of the strands of the mat.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to oil and gas wells. More particularly, the present invention relates to an improved method and apparatus for predicting the state properties of a multi-phase fluid at any point within the fluid conduit of an oil and gas well. 2. Description of the Related Art Oil and gas have been extracted from the subsurface of the earth for many decades. Well holes are drilled into the earth until a reservoir of fluid is reached. The underground fluid is then extracted and refined for various purposes. As with most oil and gas wells, the extracted fluid is a multi-phase mixture of oil, water, and gas. The gas itself is in two forms, free gas and gas that is in solution either with the oil or with the water. The monitoring of the production of fluid from oil and gas wells continues to be an important activity. Not only is monitoring necessary for obvious economic reasons, but also as an indicator of serious problems, such as leaks in the piping making up the well. Currently, oilfield service companies physically insert a measuring tool into the flow conduit of a well to measure fluid characteristics such as temperature, pressure, and total flow rate. The process of physically measuring and recording the flow in a well hole is called production logging. At best, a production log may provide an accurate snapshot of production information at the particular time that the measurements are made. However, this information can change relatively quickly, especially in a well with multi-zone production where the production from one zone can affect the production in another. There are several other problems involved with prior art production logging methods. First, the measuring device that is used has a finite size, so it disturbs the flow that it is trying to measure and introduces error into the measurement and subsequent calculations. Second, the measuring device must be calibrated in the well. Unfortunately, the well cannot be producing while the measuring device is being calibrated so the calibration period results in a loss of revenue for the oil well owner. Consequently, current production logging methods are not entirely satisfactory. There has been, therefore, a need, for a variety of methods and/or of devices for production logging that can measure accurately the production capacity of an oil and gas well without disturbing the fluid flow during measurement and more specifically, there exists a need for using two sets of stabilized surface production tests to more accurately predict the results of a well analysis. There is also a need in the art for a method that does not require the well to be shut down during calibration of the measuring instruments for this stabilized data. It is an object of the present invention to solve the problems inherent in the prior art methods and to give an accurate surface production test information. It is a further object of the present invention to utilize existing equipment on the wellhead to enable remote monitoring of well production. SUMMARY OF THE INVENTION The present invention solves the problems inherent in the prior art. The evaluation program of the present invention is capable of performing a series of functions necessary to calculate the characteristics of the multi-phase fluid flow along the predefined geometry of the well hole and eliminating or reducing the existence of erroneous surface production test data by providing an accurate data combination by taking data at different points in time in order to determine the existence of accurate stabilized production data for use in well analysis. Using this improvement an evaluation program divides the geometric profile into a series of discrete segments of a predefined thickness, starting at the wellhead and ending at the last reservoir. Starting at the wellhead, the evaluation program trains, segment by segment, wellhead data until the end point is reached. At the starting point, the wellhead temperature and pressure, the wellhead geometric profile, the wellhead gas production rate, and the oil, condensate and water production rates are provided. To determine the conditions at the segment just below the wellhead, the evaluation program extrapolates the temperature profile to estimate the temperature at that particular segment location. Similarly, the geometric profile is extrapolated to determine the geometric configuration of the segment at that particular location in the fluid conduit. Using the total flow rate at the previous step (in this case, at the wellhead), an estimated pressure is calculated for that particular segment. The estimated pressure, estimated temperature, estimated geometry are used to calculate an estimated total flow rate of the fluid in the well hole at that particular location. These estimated values are used to correlate the phase segregation of the fluid at any one segment, and then to act as the initial values for the next segment farther down the well hole. These steps are repeated until the end point of the well hole is reached. The improvement imposes using a pair of stabilized surface production tests to determine if a minimum point exists for the change in pressure with the change in total gas production rate for a given change in total liquid production rate between the two tests. If the minimum point exists then the pair of stabilized surface production test is accurate, if not then the pair of tests is not possible and another pair of tests should be investigated until an accurate pair of tests is found. This method is also useful for estimating the phase segregation of the fluid in the well. Once the phase segregation can be determined at each step within the well geometry, the constituent flow rates of the gas, water, and oil can also be calculated. These velocity rates are useful in determining if apparent flow rate losses are due to liquid drop-out (retrograde condensation) of the gas. Furthermore, apparent fluid flow losses or gains at particular steps can be attributed accurately to thief zones or production zones, respectively. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a computer system of the present invention; FIG. 2 shows a conventional well hole; FIG. 3 shows a flowchart of the method of the present invention; FIG. 4 shows a conventional well hole that is divided into segments; FIG. 5 shows a segment of a fluid conduit; and FIG. 6 shows a typical oil or gas well using the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention is an improvement over a method using stabilized surface test data to determine fluid properties at the points of influx or efflux in the flow conduit (well hole). The fluid in question can be from any well through which gas and at least one other liquid phase is being commingled and produced. Such a fluid is called a multi-phase fluid. The method of the present invention applies to any well producing either of the following combinations of fluids: a) gas, oil, and water; b) gas and oil, c) gas and water, d) gas, condensate, and water, or e) gas and condensate. This method does not apply to either dry gas well or dead oil wells. In addition, the method of the present invention does not apply to wells on rod pumps where the fluids are separated and the wellhead pressure is near atmospheric pressure. The method of the present invention determines the flow properties and information such as the depth of production zones (influx) and the depth of thief zones (efflux). The present invention also determines the productivity indexes (PI) or infectivity index (II) of the zones. Points of influx are normally attributed to the following: productive zone, points of liquid channeling into the flow conduit, liquid “drop out” in a gas well, gas injection in a continuous flow gas lifted well, and lift points for a well with an electric submersible pump or hydraulic pump. Points of efflux are normally attributed to the following: thief zones and leaks in the flow conduit. Another embodiment of the present invention constitutes an improvement which can be applied to an oil or gas well as long as the well produces either of the following fluid types at the wellhead: a). Gas, oil, and water; b). Gas and oil; or c). Gas and water. To perform the method of the original invention, three categories of data were needed: 1) stabilized surface production test data, 2) fluid property data, and 3) the flow conduits geometric profile data. This improvement requires the following data for each applicable well type: 1). Two stabilized surface production tests. Each test must include the following information: a). Total gas production rate; b). Total oil production rate; c). Total water production rate. The stabilized surface test data required by the original invention was taken regularly on a producing well, typically at the wellhead. The stabilized surface test data needed was: a) the wellhead pressure, b) the gas production rate, and c) the oil, condensate, and water production rates. The use of stabilized surface test data (wellhead data) was preferred because the data was less expensive to obtain than inserting probes into the fluid conduit. Furthermore, unlike the prior art probe insertion method, no well down-time is required for the method of the present invention. The required fluid property data for the method of the original invention comprised: a) the API gravity of oil or condensate, b) the specific gravity of water (if any), c) the specific gravity of the gas produced, d) the wellhead temperature, and e) the bottomhole temperature. The method of the original invention divided the flow conduit into a series of segments. Geometric profile data was needed at each segment. The data needed for each segment included: a) the true vertical depth, b) the measured depth, and c) the internal diameter (used to calculate the cross-sectional area). Generally, these data are provided at specific points along the fluid conduit. Data for points in between are interpolated using common algorithms. The information for the stabilized surface production test needed for this improvement must be different for the two tests except when either the total oil production rate or the total water production is zero for both tests. The improvement requires data known as well fluid PVT data. This data must include the following: a). API gravity of the oil; b). Specific gravity of the gas; c). Specific gravity of the water; d). Average wellhead temperature; and e). Average bottomhole temperature. Further for the improvement to work, the measured depth of the wellhead where the wellhead pressure measurements are made must be known. Note that the reference point for this measurement should be the same as for all other measured depth measurements provided in items 4 and 5 to follow; Also, the measured depth of the end of each segment of tubing of a constant internal diameter and the internal diameter of the segment of tubing must be ascertained. This information should be provided from the wellhead to the bottom of the well; and Additionally, the measured depth and true vertical depth of the end of each segment of tubing of a constant inclination angle (Deviation Survey) is needed to perform the necessary computer calculations. This information should be provided from the wellhead to the bottom of the well. This well data is what is needed to perform multiphase flow modeling from the wellhead to the bottom of the well of the existing improvement. The method of the original invention was best accomplished with the use of a digital computer. A software program that embodied the steps proscribed therein was executed on the digital computer to achieve the desired results. As shown in FIG. 1, the improvement uses a computer system comprising a personal computer 30 . The average personal computer produced today is sufficient for these purposes. Connected to the computer 30 is a display monitor 32 that is capable of displaying the results from the software program. A keyboard 34 and/or mouse 38 are used to input the data about the well. Optionally, a printer 36 is also connected to the computer 30 so that hard copies of the results from the software program can be produced. In the preferred embodiment of the present invention, a sufficient amount of storage capacity is included with the computer 30 to store all of the fluid information at each segment along the well. The stored information about each segment, along with the input data, can then be presented on display 32 or printed on printer 36 . FIG. 2 shows a typical oil and gas well. The well 10 is composed of a reservoir 28 that contains the desired fluid (usually oil and/or natural gas). Pipe 26 is drilled into the ground until it reaches reservoir 28 . Once drilled, pipe 26 acts as a conduit to remove the fluid from the reservoir 28 . There may be multiple reservoirs along the well 10 . As shown in FIGS. 2 and 4, the extracted fluid flows from the reservoir 28 to the wellhead 20 . An out-take pipe 24 takes the fluid from the wellhead 20 to the separator 22 where the multi-phase fluid is separated into its constituent elements, namely oil, water, and gas. The geometric profile of a typical segment is shown in FIG. 5 . Referring to FIG. 5, the geometric profile for each segment comprises the internal diameter 43 , the measured depth 42 , and the true vertical depth 40 . As shown in FIG. 4, the wellhead is defined by the cross sectional area of the well along the hole running from the starting point 21 (typically at the wellhead 20 ) and the ending point 23 (typically at the last reservoir 28 ). This cross-sectional area at any given point along the well is designated by the symbol “A.” The set of areas along the well hole is designated by the symbol “G.” The cross-sectional area usually known at several points along the well. The geometric profile is considered to be predefined for purposes of the present invention and constitutes one set of the input data values. An estimated value of A at any point along the well can be estimated by using standard straight-line or curve interpolation algorithms with G as input to the interpolation algorithm. As with the geometric profile, the temperature profile of the well from the starting point 21 to the ending point 23 is usually well known. For purposes of this disclosure, the temperature at any given point along the well is designated by the symbol “T.” The set of temperature data along the well hole is designated by the symbol “H.” The temperature profile H is considered to be predefined for purposes of the present invention and constitutes one set of the input data values. An estimated value of T at any point along the well can be estimated by using standard straight-line or curve interpolation algorithms with H as input to the interpolation algorithm. Two other parameters, in addition to the temperature T and area A, define the characteristics of the fluid at any given point in the well. Those two parameters are the pressure (designated by the symbol “P”) and the total fluid flow rate (designated by the symbol “W t ”). The total fluid flow rate W t is defined by the following formula: W t =W o +W w +W gf +W gs where W o is the flow rate of oil, W w is the flow rate of water, W gf is the flow rate of free gas, and W gs is the flow rate of the gas that is in solution. Typically, the pressure and total flow rate are known only at the wellhead. The total flow rate, W ti , may itself have been calculated knowing the specific gravity of the fluid at the wellhead. The wellhead pressure and the wellhead total flow rate constitute the final two input data values for the present invention. As shown in FIG. 3, the program is started (step 100 ) and the input data values are read in step 102 . The input values consist of the temperature profile H, the geometric profile G, the wellhead pressure P i , and the wellhead total flow rate W ti . The input data is calibrated in step 104 . In the preferred embodiment of the present invention, a user-friendly software program, called a front-end, performs steps 102 and 104 of FIG. 3 and is used to format the input data for the evaluation program. The technique for the multi-phase flow correlation is defined by Beggs and Brill. See Beggs, H. D. and Brill, J. P., “A Study of Two-Phase Flow in Inclined Pipes,” Journal of Petroleum Technology (Many 1973), pp. 607-619, included herein by reference for all purposes. While there are many multi-phase flow correlations in use today, the Beggs and Brill technique was the simplest to program on a digital computer. It will be understood by those of ordinary skill in the art to use other techniques for multi-phase flow correlation without departing from the scope of this invention. In order to avoid unnecessary calculation of bad data the calibrated data is checked in step 106 . If the input data is bad, the program is terminated immediately in step 130 . However, if the data is valid, step 108 is executed. In step 108 , the length of the well hole is divided into equal-length sections. Each section is called a segment and each segment is separated, in the preferred embodiment, by 0.01 feet. Shorter segment lengths increase the accuracy of the results. However, segment lengths less than 0.01 feet do not significantly increase the accuracy. Segment lengths much greater than 0.01 feet generally yield inaccurate results. Longer wells require more segments. Consequently, the computer must have sufficient memory to retain data at each segment if such data are requested by the user. According to step 108 of FIG. 3, each segment is assigned a number. As shown in FIG. 4, the first segment (i) is at the wellhead and the last segment (j) is at the last reservoir. The segments are in sequential order, i.e., i, i+1, i+2, . . . , j−2, j−1, j. Segments at any given point along the well hole are designated by the letter “k,” e.g., T k or P k . Correspondingly, the next segment down-hole after segment k would be segment k+1. As mentioned previously, the only place where the fluid characteristics are well known is at the wellhead. Thus, T i , A i , P i , and W ti are used as the initial values and are loaded into the k registers of the evaluation program, T k , A k , P k , and W tk , respectively (i.e., setting k=i), as shown in step 110 of FIG. 3 . The value of k indicates the current segment number. Given the two surface production tests and other well data PPPM initially calibrates the data to fit the actual well data to the multiphase flow correlation used, which is in the PPPM program the Beggs and Brill correlation, and the various black oil models used. The black oil models used are the more popular ones used and are chosen because of its programming ease. Once calibration is completed the pressure profiles are computed for the surface production tests in the flow conduit. The profiles are computed beginning at the wellhead and moving in an increasing measured depth sequence. This is illustrated in step 112 and 114 in FIG. 3 . The changes in the profiles give indications of points of influx or efflux. Once the last section of flow conduit is reached then PPPM calculations are completed. Once step 118 is complete, or if W t(k+1) and W tk were found to be equivalent in step 116 , then step 120 is performed. In step 120 , the phase segregation is determined by the multi-phase flow correlation techniques mentioned above. Once the phase segregation is determined, differences between the phases as segment k+1 can be compared to the phase segregation in segment k. These phase segregation differences are used to calculate flow velocities of the various phases, i.e., oil velocity V o(k+1) , gas velocity V g(k+1) , water velocity V w(k+1) and, finally, the total (average) velocity of the fluid V t(k+1) . In step 122 , a check is made to see whether or not all of the segments have been addressed. If so, the results are output in step 126 either to display 32 and or to the printer 36 and the program is terminated. Otherwise, k is incremented in step 124 and the program is continued at step 112 . Execution continues until all segments have been addressed (e.g., k=j). For standard oil and gas wells, the method of the present invention determines the mid-depth of production or injection for each productive or thief zone. This mid-depth of production or injection should correspond to the mid-depth. If it does not, then formation damage and/or plugging of the fluid conduit perforation is indicated. The method of the present invention also determines the depths of liquid “drop-out” of either condensate or water for a gas well producing water and/or condensate. The latter information is necessary for determining the depth at which artificial lift equipment should be set to prevent liquid loading problems in a gas well that is producing water and/or condensate. It should be noted that the method of the present invention can also distinguish between the “drop-out”of condensate or water, and a productive or thief zone. While the absolute value of the PI or II for each zone is itself meaningless, comparison from zone to zone in the same well, or for the same zone in the same well from time to time, can provide accurate results. For a well on continuous flow gas lift, the method of the present invention determines the gas injection depth. In addition, the as with the well described previously, the method of the present invention can also distinguish between the “drop-out” of condensate or water and productive or thief zone. This index at each depth of gas injection provides a measure of valve performance as the valve sits in the wellbore. For a well using an electric submersible pump (ESP) or hydraulic jet pump or hydraulic piston pump, this index at pump depth provides a measure of pump performance as the pump sits in the wellbore. Finally, this index for the well at each of its productive zones provides a measure of well productivity which, in the prior art, could be obtained only by pulling the pump to test the productive zones. For the well shown in FIG. 6 in a typical stabilized surface production test the wellhead pressure is measured at Point 1 and the total gas production rate, total oil production rate and total water production rate are all measured at the separator 131 over a test period of approximately 4-24 hours. Excluding the application of the 3PM technology this surface production test data is used to make engineering and economic decisions on the well. This stabilized surface production test data is normally either totally averaged over the test period or the wellhead pressure portion is taken instantaneously at the end of the test period and the total fluid production rates portion averaged over the test period. Stabilization is assumed to occur over the test period. For either method of taking stabilized surface production test data the following operational problems occur stemming from the fact that although the wellhead pressure is measured instantaneously at the wellhead (Point 1 in FIG. 6) all total fluid production rates are not measured instantaneously but measured over time at the separator some distance from the wellhead (FIG. 6 ): 1). The total gas production rate at the wellhead is less than the total gas production rate at the separator. The total oil production rate and total water production rate at stock tank conditions are the same as at the wellhead and separator. The reason for the total gas production rate at the separator being larger than the total gas production rate at the wellhead is due to gas increasingly coming out of the solution of the oil as pressure decreases when the oil moves from the higher pressure wellhead to the lower pressure separator; and 2). Fluctuations in flow conditions at the wellhead initiated by the reservoir 135 are felt at the separator after a finite amount of time. The flowline 132 connecting the wellhead to the separator can be quite long increasing this amount of time. As can be seen these operational problems can cause erroneous stabilized surface production test data regardless of the averaging procedure. This technology utilizes two stabilized surface production tests with each test taken over a different test period. In applying this technology two test periods of tests are needed utilizing data from different parts of each test period to determine the existence of an accurate data combination of two stabilized tests for which to use in the 3PM technology as well as other technologies to for well engineering and well economics purposes. This technology utilizes The Beggs and Brill 1 correlation to perform multiphase flow modeling. In performing multiphase flow modeling Black Oil fluid property correlations are used. Note that the theory behind this technology applies regardless of the type of multiphase flow correlation used as well as the type of Black Oil fluid property correlation used. In the case of a well having more than one completion this technology can be applied to each completion as long as the above conditions are met. Also this technology can be applied to a well on artificial lift as long as the above conditions are met.	An improved apparatus and improved method for determining the characteristics of a multi-phase fluid along a well hole having a predefined geometric profile are presented. Various state properties of the fluid, including the temperature, pressure and specific gravity are taken at the wellhead and used as starting values for calculating estimated state properties at various segments along the well hole. Once the state properties are calculated, an estimated mass flow and velocity rate for the fluid and its constituents can be calculated at specific points along the well hole by implementing computer-based programs and algorithms to extrapolate and/or iterate the known parameters and measurements in a progressively incremented manner from the locations of such given starting points at an initial segment up to other further points corresponding to a set of further sequential segments used in the geometric profile mathematical model.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 61/752,295, filed Jan. 14, 2013, and the contents of which are hereby incorporated by reference in its entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not applicable. REFERENCE TO APPENDIX [0003] Not applicable. BACKGROUND OF THE INVENTION [0004] The present invention relates to oil well pumps and more particularly to an improved hydraulic oil well pump that is electronically controlled using limit or proximity switches to control a valving arrangement that eliminates shock or excess load from the pumping string or sucker rod during pumping, and especially when changing direction of the sucker rod at the bottom of a stroke. In one embodiment, a time delay halts the movement of the sucker rod or pumping string to allow accumulation of oil in a slow following well. In another embodiment, the pumping string rapidly falls to the bottom of the stroke in order to shake or jar debris from the string. BRIEF SUMMARY OF THE INVENTION [0005] The present invention provides a hydraulic oil well pumping apparatus. The system of the present invention utilizes a hydraulic cylinder having a piston or rod that is movable between upper and lower piston positions. A pumping string or sucker rod extends downwardly from the piston, the pumping string or sucker rod being configured to extend into an oil well for pumping oil from the well. [0006] A prime mover such as an engine is connected to a compensating type hydraulic pump. [0007] A directional control valve moves between open flow and closed flow positions. A hydraulic flow line connects the pump and the hydraulic cylinder. [0008] Electronic controls are provided that control movement of the piston as it moves between the upper and lower positions. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0009] For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein: [0010] FIG. 1 is an exploded, elevation view of the preferred embodiment of the apparatus of the present invention; [0011] FIG. 2 is an elevation view of the preferred embodiment of the apparatus of the present invention; [0012] FIG. 2A is a partial elevation view of the preferred embodiment of the apparatus of the present invention; [0013] FIG. 3 is a sectional view of the preferred embodiment of the apparatus of the present invention, taken along lines 3 - 3 of FIG. 2 ; [0014] FIGS. 4A , 4 B and 4 C are fragmentary, elevation views of the preferred embodiment of the apparatus of the present invention illustrating operation of the apparatus; [0015] FIG. 5 is a partial perspective view of the preferred embodiment of the apparatus of the present invention; and [0016] FIGS. 6-7 are schematic diagrams of the preferred embodiment of the apparatus of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0017] The Figures described above and the written description of specific structures and functions below are not presented to limit the scope of what Applicants have invented or the scope of the appended claims. Rather, the Figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation-specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation, location and from time to time. While a developer's efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of skill in this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Lastly, the use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like are used in the written description for clarity in specific reference to the Figures and are not intended to limit the scope of the invention or the appended claims. [0018] FIGS. 1-7 show generally the preferred embodiment of the apparatus of the present invention designated generally by the numeral 10 . [0019] Oil well pump 10 provides a reservoir 11 for containing hydraulic fluid. A prime mover 12 such as an engine is provided for driving a compensating pump 13 . The pump 13 is used to transmit hydraulic pressure, pressurized hydraulic fluid received from reservoir 11 via flow line 33 to a hydraulic cylinder or petroleum lift cylinder 14 . Lift cylinder 14 can be a Parker (www.parker.com) model GG699076A0. The hydraulic lift cylinder 14 includes a cylinder body 15 having a hollow interior 16 . [0020] A cylinder rod 17 is mounted in sliding or telescoping fashion to the cylinder body 15 extending into the interior 16 of cylinder body 15 . The cylinder rod 17 has an upper end portion 18 and a lower end portion 19 . During use, the lower end portion 19 extends below cylinder body 15 as shown in FIGS. 1-4C and 6 - 7 . [0021] In FIG. 1 , the lower end portion 19 of cylinder rod 17 is attached with coupling 20 to a pumping string or sucker rod 21 . The pumping string or sucker rod 21 is comprised of a number of joints, connected end to end. A pumping part of the sucker rod 21 is generally positioned next to a perforated zone of the well. Such a pumping string 21 or sucker rod 21 is known in the art and is used to pump oil from an oil well as the sucker rod 21 moves up and down. [0022] The lift cylinder 14 is mounted upon Christmas tree 22 . The Christmas tree 22 is mounted at the well head of an oil well at the upper end portion of well pipe 23 . A suitable structural frame 38 can be used for supporting hydraulic cylinder 14 and its cylinder rod 17 above Christmas tree 22 as shown in FIGS. 1-4C and 6 - 7 . [0023] A plurality of proximity or limit switches 24 , 25 , 26 are provided. Switches 24 , 25 , 26 can be for example those manufactured by Turck Company, model number N120-CP40AP6X2/510. As shown in FIGS. 2-2A , these proximity or limit switches 24 , 25 , 26 can be mounted to frame 38 . During use, these proximity or limit switches 24 , 25 , 26 can be used to sense the position of the lower end portion 19 of cylinder rod 17 and then send an electronic signal to the controller 39 (commercially available), then the controller 39 sends a signal to the manifold 35 that includes directional valve 28 , proportioning valve 31 , and ventable relief valve 37 (e.g. Parker Sterling model no. AO4H3HZN). [0024] Hydraulic fluid flow lines are provided for transmitting hydraulic fluid under pressure to hydraulic lift cylinder 14 via flow lines 27 , 29 . Directional valve 28 receives flow from flow line 29 . Flow line 27 extends between directional valve 28 and cylinder 14 . To initiate operation, pump 13 transmits fluid flow through the manually vented relief valve 37 thus removing pressure from the system prior to start up. When the engine or prime mover 12 is started, it activates the hydraulic pump 13 , flow still initially traveling through the relief valve 37 and flow line 34 to reservoir 11 . [0025] The cycle of operation begins by vent closure of valve 37 so that oil flowing in flow line 29 now travels to directional valve 28 . At about the same time, the directional valve 28 is energized so that oil under pressure is directed via flow line 27 to hydraulic lift cylinder 14 body 15 and its hollow interior 16 . The cylinder rod 17 will then elevate, lifting the pumping string 21 or sucker rod 21 with it (see FIG. 2 ). In one embodiment, a delay cycle is provided wherein the cylinder rod 17 and pumping string 21 remain in this elevated position for a selected time interval. This time delay in the elevated position is used when the well is slow flowing. A well can be slow flowing when the oil is more viscous or if the well is an older well with a lesser volume of available oil to pump. The delay cycle must first be turned on via the HMI (human machine interface). Once this is done the operator can adjust the amount of time that the cylinder pauses (delays) at the top of the stroke. The amount of time of the delay may be 0 seconds to 65000 seconds (18 hours). This can be changed if needed. The delay cycle offers several benefits. The delay cycle allows gas separation at the down hole pump intake—resulting in greater pump efficiency. The delay cycle minimizes rod reversal effect, which allows the rod time to relax before starting its downward stroke. The delays also allows the tubing fluid load above the travel valve time to equalize with the standing valve—resulting in reduced fluid pound effect at the down hole rod pump. [0026] Frame 38 carries the plurality of proximity or limit switches 24 , 25 , 26 . When the cylinder rod 17 reaches the top of its stroke, the proximity switch 24 (which is an uppermost proximity switch) senses the position of coupling 20 and energizes the directional valve 28 so that it closes the flow line 29 and flows through proportional valve 31 . Valve 31 is a manual proportional valve with flow check for restricted flow on return of hydraulic oil to the reservoir, thus allowing a restricted flow to control the rate of descent of cylinder rod 17 . Because the pump 13 is a compensating pump, it continues to run but does not continue to pump fluid. It can be set to halt fluid flow at a certain pressure value (e.g. 3000 psi, or 210.92 kgf/cm2) which can be set by design depending upon the weight of sucker rod 21 . In other words, pump 13 is volume compensating and pressure responsive. Such a compensating pump is manufactured by Parker such as their model no. P1100PSO1SRM5AC00E1000000. [0027] When the directional valve 28 is used to close flow line 29 , the compensating pump 13 continues to rotate with the engine 12 but no longer pumps fluid in flow line 29 . The directional valve 28 opens drain line 30 at about the same time that line 29 is closed. Fluid in hydraulic cylinder 14 now drains via flow lines 27 and 30 through proportioning valve 31 and cylinder rod 17 descends relative to cylinder body 15 . The hydraulic fluid draining from cylinder body 15 interior 16 continues to flow via flow lines 27 and 30 through proportioning valve 31 and cooler 36 and then into flow line 32 which is a drain line to reservoir 11 . The flow line 32 can be provided with oil cooler 36 (e.g. Thermal Transfer model BOL-8-1-9) and an oil filter (e.g. Parker model no. RF2210QUP35Y9991) if desired. [0028] Since pressure no longer forces cylinder rod 17 upwardly, it begins to drop (see FIGS. 4A and 7 ). As it drops relative to lift cylinder body 15 , coupling 20 will meet a second proximity or limit switch 25 which is below limit switch 24 (see FIGS. 2 , 4 A, 4 B, 4 C). The limit switch 25 is closer to the lower end portion (for example, 1 foot, or 0.30 meters) of cylinder body 15 than to upper end portion of body 15 . When the coupling 20 reaches proximity or limit switch 25 , in one embodiment ( FIG. 2A ) it signals the directional valve 28 that it should switch to allow the flow of fluid to travel through the proportioning valve 31 via flow lines 27 , 30 . [0029] The proportioning valve 31 is a manual proportioning valve with flow check for restricted flow on return of hydraulic oil to the reservoir. When the coupling 20 reaches the proximity or limit switch 25 , the directional valve switches to direct the flow to lift the cylinder 14 . The choking action that takes place in the proportioning valve 31 has the effect of gradually slowing the speed of the cylinder rod 17 and its connected sucker rod 21 . The use of Parker No. FMDDDSM Manapac manual sandwich valve located between directional valve and the solenoid controls dampens the transition of the directional valve from the upstroke or downstroke to allow bumpless transfer of fluid to the cylinder 14 and balances pressures. This choking of flow by the proportioning valve 31 also slows action of cylinder rod 17 , preventing undue stress from being transmitted to the sucker rod 21 as the bottom of the downstroke of cylinder rod 17 is approached, then reached. [0030] Directional valve 28 can be a Parker® valve model number D61VW001B4NKCG. Proportioning valve 31 can be a Parker® valve model number DFZ01C600012. [0031] In one embodiment, the cylinder rod 17 and pumping string 21 are allowed to fall without any slowing. This free fall of rod 17 and string 21 from the elevated position to the rod 17 lowest position. Such free fall creates a jar or shock that dislodges any trash or unwanted debris from the string 21 . The operator turns the clean cycle on via the HMI. After the clean cycle is turned on, the next stroke down will perform the clean function event. The event starts by pumping the cylinder to the top of the stroke. For the current embodiment, it goes to the top switch. After reaching the top switch the down stroke for the clean out cycle begins. The bypass valve opens and the direction valve closes (resulting in the pump de-stroking to bypass pressure). The proportional valve ramps open to 75%, and the cylinder is drained resulting in the down stroke. The middle switch is ignored (this is unique for this function). When the bottom switch is detected the proportional valve is shut closed (not ramped; also unique). This has the benefit of creating a gentler “abrupt” stop by closing the proportional valve very quickly (not ramping it closed). This triggers the end of the clean out cycle. The function is turned off and the normal cycle resumes. Alternatively, the step requiring an operator to turn the cleaning cycle on may be eliminated, and this cleaning or cleanout cycle may be scheduled to automatically occur at a selected interval. [0032] In one embodiment, an improved direct mount smart cylinder that does not use proximity switches may be used with an oil well pump, including sucker rod pumping. As a result, this embodiment does not require the use of a pedestal, though one may still be used if warranted. A linear displacement transducer may be installed inside the direct mount smart cylinder in order to measure the linear displacement of the rod of the oil well pump. The direct mount smart cylinder is able to determine the position of the rod without the use of proximity switches. A hall effects linear displacement transducer may be used. [0033] The direct mount smart cylinder embodiment offers several benefits. It minimizes the possible points of oil leaks because a stuffing box is no longer needed. The height of the oil well pump may be reduced by half when a direct mount smart cylinder is implemented. The connection to the well is improved because no guy wires are used with the direct mount smart cylinder. The direct mount smart cylinder provides the position through the stroke instead of only at the location of the proximity switches. Because only one cable runs to the linear displacement sensor instead of multiple proximity sensors, the assembly of the oil well pump is easier and is safer because there are fewer loose electronics. The stroke length may be changed through the control system human machine interface without having to move proximity sensors. There are fewer or no moving parts in sight on the wellhead. The linear displacement transducer is a no wear item. The direct mount smart cylinder embodiment also increases the ability to change the speed on the fly. [0034] Other and further embodiments utilizing one or more aspects of the inventions described above can be devised without departing from the spirit of Applicant's invention. Discussion of singular elements can include plural elements and vice-versa. [0035] The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions. [0036] The inventions have been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by the Applicants, but rather, in conformity with the patent laws, Applicants intend to fully protect all such modifications and improvements that come within the scope or range of equivalent of the following claims.	A hydraulic oil well pumping arrangement employs a compensating type hydraulic pump, a directional valving arrangement and a proportioning valving arrangement. When the directional valve is energized, oil is directed to the rod end of the hydraulic cylinder. In one embodiment, a time delay halts the movement of the sucker rod or pumping string to allow accumulation of oil in a slow following well. In another embodiment, the pumping string rapidly falls to the bottom of the stroke in order to shake or jar debris from the string.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND As exploration in the oil and gas industry has expanded, increased safety and environmental concerns have caused oil and gas exploration and drilling contractors to require an intermediate protection casing to be used between the surface casing and the conventional intermediate casing. Casing hangers of this type must provide sufficient weight carrying capacity with their support mechanisms while maintaining a pressure capacity comparable to that of the casing being suspended. Typically, hangers have failed in one way or another to meet these criteria. Often their use requires that the bore of the previous casing hanger be unduly restricted if a mandrel shoulder type hanger is used while the use of an expanding type hanger often requires undue restrictions in the annulus between the protection and surface casings, causing problems during cementing and circulating operations. This invention is for an improved wellhead casing hanger particularly suited for use in situations where the annular spacing between successive casing strings is inordinately small. The present invention provides a unique wellhead hanger system which provides improved weight capacity, increased flow return area and full bore access to the protection casing below the hanger. Prior casing hangers used in situations where the annular spacing between successive casing strings is inordinately small include two types of devices. The first type of these is disclosed by U.S. Pat. No. 3,421,580 which shows an expanding type hanger to suspend the protection casing. The expanding type hanger lands in a specially profiled circumferential groove in the surface casing hanger with flow return passages formed in the wall of the surface casing hanger. A similar structure is found in U.S. Pat. No. 3,847,215 wherein the expanding type hanger is used to suspend multiple tubing strings with flow return passages formed in the surface casing hanger in which it is landed. The second type of casing hanger is shown in U.S. Pat. No. 3,592,489 wherein a shouldered or mandrel type hanger lands on a circumferential seat or shoulder protruding from the surface casing hanger's bore. Flow return passages are formed in the surface hanger's wall with the protruding shoulder split into a plurality of arcuate segments which are radially movable by piston means. A similar type of hanger is manufactured by FMC Corporation and is shown in the Composite Catalogue published by World Oil Publishing, '88-'89 Edition, Volume 2, p. 1497. The FMC structure differs from the structure of U.S. Pat. No. 3,592,489 by having the protruding shoulder an integral part of the wellhead housing. SUMMARY The present invention provides an improved wellhead casing hanger for suspension of concentric casing strings with small annular spacings. The improved wellhead casing hanger has an outer adapter sleeve installed in the surface casing string, an expanding type hanger for suspending the protection casing and a means for sealing the annulus therebetween. The adapter sleeve is composed of a pair of concentric cylindrical members with the inner member providing the mating shoulder or seat on which to land the expanding type hanger and the outer member providing pressure integrity and increased flow return area. The inner and outer cylindrical members are sealingly connected to one another and installed in the surface casing string at the appropriate point. There is an annular gap between the lower extremity of the inner and outer members allowing flow returns into the annulus therebetween. Flow return passages formed in the inner member adjacent the engagement point with the outer member complete the flow return path around the protection casing hanger. The expanding type hanger is landed on the shoulder provided in the inside wall of the adapter sleeve. A combination casing and packoff installation too is then used to install the annulus seal means. An object of the present invention is to provide an improved wellhead casing hanger which provides increased flow return area, pressure capacity and weight supporting capacity. Another object is to provide an improved wellhead casing hanger which allows the protection casing to be suspended at any convenient point in the surface casing string. A further object is to provide an improved wellhead casing hanger for protection casing which will pass through a wellhead without requiring the removal of the nominal bore protector. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the present invention are set forth below and further made clear by reference to the drawings wherein: FIG. 1 is an elevation view, partly in section, of a wellhead and guide base with the adapter sleeve of the present invention installed at the lower end of the well-head. FIG. 2 is a sectional view showing the improved protection string casing hanger of the present invention being lowered into the adapter sleeve. FIG. 3 is a sectional view showing the improved protection string casing hanger landed in the adapter sleeve. FIG. 4 is a sectional view showing the improved protection string casing hanger with the annulus seal means and its installation tool therein. FIG. 5 is a sectional view showing an alternate embodiment of the improved protection string casing hanger with the annulus seal means and its installation tool therein. DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, guidance means 2 is located on the sea floor and includes permanent guide base 4 with guide posts 6 attached thereto and latching means 8 circumferentially spaced about central bore 10. Guidance means 2 in the form of wire cables 12 are attached to each guide post 6 and extend to the ocean surface for attachment to conventional tensioning means, not shown. Within central bore 10 is located landing shoulder 14 for receiving a mating shoulder 16 on conductor housing -8. When conductor housing 18 is landed on shoulder 16, pin 20 of latching means 8 engages upwardly facing shoulder 22 and thereby locks housing 18 from vertical movement with respect to guide base 4. Conductor pipe 24, typically 30" in diameter, attaches to conductor housing 18 by suitable means, such as welding (not shown). Conductor housing 18 has inside upper shoulder 26, tapering inwardly and downwardly, upon which mating tapered shoulder 28 of wellhead 30 rests. Attached to wellhead 30 by suitable means, such as butt weld 32 is adapter sleeve 34 of the present invention which will be more fully described below. Connected to adapter sleeve 34 by suitable means, such as butt weld 36, is surface casing 38, typically 20" in diameter. Referring now to FIG. 2, the lowermost portion of wellhead 30 is shown with adapter sleeve 34 connected thereto. Adapter sleeve 34 includes generally cylindrical inner member 40 and outer member 42. Members 40 and 42 are sealingly and structurally connected by casing threads 44. Enlarged portion 46 of inner member 40 abuts wellhead 30 and is connected thereto by weld 32. Outer surface 47 tapers inwardly and downwardly to central section 48 which extends substantially axially and terminates with external tapered casing thread 44 formed thereon. Radius 50 connects thread 44 with reduced outer portion 52 which extends axially to lower end 54 of inner member 40. Inside surface 56 extends substantially axially and is connected to surface 58 by conical surface 57, which tapers inwardly and downwardly. The lower end of inside surface 58 is connected to bore 60 by beveled surface 59 which tapers downwardly and inwardly. Bore 60 terminates at tapered surface 62 which tapers downwardly and outwardly to intersect surface 64 which extends downwardly. Flow return passages 66 extend through sleeve 34 and obliquely intersect reduced outer portion 52 and surface 64, thereby allowing fluid returns to pass from annulus 68 to annulus 70. Surface 64 is connected to guidance surface 72 by conical surface 71, which tapers downwardly and inwardly. Guidance surface 72 is connected to clearance surface 76 by conical surface 74, which tapers downwardly and outwardly. Clearance surface 76 extends axially downward to load surface or shoulder 78, which tapers upwardly and inwardly to restricted bore 80. Bore 80 extends slightly downward and is connected to lower guidance portion 82 of inner member 40 by downwardly and outwardly tapering conical surface 84. Outer member 42 is connected to inner member 40 by casing thread 44 and central portion 85 depends therefrom to lower portion 86 of reduced diameter. Surface 52 of outer member 42 and the interior of central portion 85 define annulus 68 therebetween. Fluid returns in the annulus between the surface and protection casing strings flow upwardly into annulus 68, and through flow return passages 66 to annulus 70. The reduced diameter of lower portion 86 allows attachment of surface casing 38 by conventional means, such as welding 36 or threading. Referring now to FIG. 3, protection string casing hanger 88 and packoff 90 have been lowered into position by combination tool 92 into adapter sleeve 34. Protection string casing hanger 88 is a generally tubular member with upper portion 94 having external latch threads 95 to receive packoff 90. Substantially thicker central portion 96 has internal grooves 98 and external groove 100 disposed axially below grooves 98. Lower portion 102 is threaded internally to receive the protection casing 104. External groove 100 is further defined by cylindrical surface 106 with upper and lower end surfaces 108 and 110, respectively. Sitting within groove 100 is load ring 112, restrained from axial movement with respect to hanger 88 by end surfaces 108 and 110. Load ring 112 is a generally split ring with outer surface 114 having a keyed profile to allow engagement with inner member 40 of adapter sleeve 34. The keyed profile consists of outer surface 114 interrupted by proximal bearing surface 116, tapering inwardly and upwardly to profile surface 118, which closely fits adjacent restricted bore 80. Profile surface 118 extends axially downward to conical surface 120, which tapers outwardly and downwardly to outer surface 121. Load ring 112 has a circumferential section removed thus allowing load ring 112 to contract radially to pass diametrical restrictions and then expand to its relaxed i.e. load bearing diameter. Combination tool 92 is best seen in FIG. 3 with protection string casing hanger 88 in its landed position and packoff 90 held in a retracted position. Combination tool 92 includes inner body 122 in close fitting and threaded engagement with outer body 124. Outer body 124 is a generally tubular member with upper portion 126 having bore 128 with internal threads 130 which structurally connect inner body 122 and outer body 124. Top plate 132 is attached to upper end of upper portion 126 by suitable means such as cap screws 134 and is in sealing engagement with inner body 122 by seal means 136. Substantially thicker lower portion 138 of outer body 124 has reduced bore 140 which slidingly receives medial portion 142 of inner body 122 and is sealed thereto by sealing means 144. Intermediately located on outer body 124 is external groove 146 with radially inwardly biased split ring 148 carried therein. Radial movement of split ring 148 is accomplished by a plurality of pins 150 moving in radial bores 152 in a manner more fully explained below. Located at the lower end of outer body 124 is a second groove 154 carrying a radially inwardly biased split ring 156. Split ring 156 has an external profile which allows engagement with grooves 98 when moved radially outwardly by a plurality of pins 158 moving in radial bores 160 as explained hereinafter. Also intermediately located on the outside of outer body 124 are seal means 162, for use during pressure testing. Inner body 122 of combination tool 92 is a generally tubular member axially movable within outer body 124 by threads 130. Below threads 130 is reduced portion 164 of inner body 122 which allows pins 150 to retract radially inward by the action of inwardly biased split ring 148. Reduced portion 164 is connected to enlarged portion 168 by conical camming surface 166. Enlarged portion 168 is connected to medial portion 142 by conical surface 170 tapering inwardly and downwardly. Medial portion 142 extends axially to conical camming surface 172, which tapers outwardly and downwardly to support portion 174. Support portion 174 is connected to lower portion 178 by conical surface 176. Lower portion 178 terminates with drill pipe thread 180. The upper end of inner body 122 contains drill pipe thread 182 for connection of the drill pipe running string 183. Packoff 90 is a generally annular member consisting of body 190 with internal groove 192 located proximate the upper end thereof. Split latching ring 194 sits in groove 192 and is biased radially inwardly and threaded internally to mate with external threads 95 of protection string casing hanger 88. Packoff 90 is retained on combination tool 92 in its retracted (running) position by a plurality of frangible members, such as shear pins 196 which are retained in a plurality of radially directed blind holes 198 in outer body 124. The lower end of body 190 has external and internal seal means, 201 and 202, respectively, which function as hereinafter described. A typical sequence of operations utilizing the improved protection string casing hanger 88 and adapter sleeve 34 begins with the structure in FIG. 1. Adapter sleeve 34 has been attached to wellhead 30 by suitable means, such as weld 32, with surface casing 38 similarly attached to the lower end of sleeve 34 by weld 36. This assembly is lowered into the position shown in FIG. 1, with shoulder 28 landed on shoulder 26. After the hole for the protection casing string has been drilled, casing hanger 88, packoff 90, combination tool 92 and protection string 104 are assembled in the following manner. Packoff 90 is positioned on tool 92 and pinned in place with shear pins 196. Inner body 122 is rotated until enlarged portion 168 forces pins 150 radially outward, camming split ring 148 to its maximum diameter so that as combination tool 92 is lowered into casing hanger 88 split ring 148 will contact end surface 91 of hanger 88. Inner body 122 is rotated downward while outer body 124 is held stationary by chain tongs, allowing support portion 174 to force pins 158 radially outward, camming split ring 156 into engagement with grooves 98 of protection string hanger 88. Simultaneously, enlarged portion 168 is moved below pins 150, allowing inwardly biased split ring 148 to contract to a diameter sufficiently small to fit inside bore 89 of hanger 88. At this point, the combination tool 92 is structurally connected to the hanger 88 and packoff 90 and the protection casing string 104 can be lowered, along with hanger 88 and packoff 90 into adapter sleeve 34. As the tool 92 and hanger 88 each the position shown in FIG. 2, outer surface 114 of load ring 112 contacts beveled surface 59 to cam load ring 112 inwardly to its fully contracted position. Further lowering of the protection casing string 104 allows profile surface 118 to come into registry with restricted bore 80, thereby allowing load ring 112 to expand to its maximum diameter. At this point, bearing surface 116 will contact load surface 78, and the weight of the protection casing string 104 will be transferred to the adapter sleeve 34, as best seen in FIG. 3. Circulating and cementing operations are next performed through bore 200 of tool 92 with flow returns passing into annulus 68, through flow return passages 66 into annulus 70 and hence to the surface. The packoff 90, as best seen in FIG. 4 is lowered into position by further rotation of inner body 122 of tool 92. This downward movement of inner body 122 moves support portion 174 from behind pins 158, allowing inwardly biased split ring 156 to retract from grooves 98, thus allowing tool 92 to move to the position shown in FIG. 4. In this position, inwardly biased split latching ring 194 engages threads 95 by first expanding and then contracting around threads 95 responsive to the downward movement, thereby locking packoff 90 to hanger 88 and sealing means 201 seals against bore 60 and sealing means 202 seals against surface 206 of hanger 88. The packoff 90 is then tested by applying suitable test pressure. If the test is unsuccessful and it is desired to retrieve packoff 90, rotation of tool 92 will cause split latching ring 194 to release from hanger thread 95, allowing retrieval of packoff 90 and combination tool 92. If the pressure test is successful, combination tool 92 is pulled upwardly, causing shear pins 196 to shear, allowing tool 92 to be removed from hanger 88 and retrieved to the surface. An alternate embodiment of the improved wellhead is depicted in FIG. 5. This alternate embodiment differs from the first embodiment only in the modification of adapter sleeve 234. Adapter sleeve 234 is composed of generally cylindrical modified inner member 240 and outer member 42. Members 240 and 42 are sealingly and structurally connected by casing threads 44 as described above. Inner member 240 is identical to inner member 40 of the preferred embodiment except for the lower guidance portion 242. Lower guidance portion 242 extends axially downward with outer surface 248 connected to end surface 254 by conical surface 250, which tapers downwardly and inwardly. Central portion 85 of outer member 42 terminates with inwardly and downwardly tapering conical section 243 which connects to lower portion 86 of reduced diameter. Conical section 243 has inside conical surface 244 against which conical surface 250 engages when outer member 42 and inner member 240 are connected by casing thread 44. A plurality of flow return slots 249 are circumferentially equally spaced in lower guidance potion 242 and extend from end surface 254 axially upward to upper slot surface 246. Outer surface 252 of inner member 240 and the interior of central portion 85 define annulus 68 therebetween. Fluid returns in the annulus between the surface and protection casing strings flow upwardly into annulus 68 through flow return slots 249 and thence through flow return passages 66 to annulus 70. In all other respects the alternate embodiment of FIG. 5 functions the same as the preferred embodiment of FIGS. 2-4. The same protection string casing hanger 88 is utilized with the modified adapter sleeve 234 as described before. Combination tool 92 is used in the same manner described above to run the casing hanger 88 and set the packoff 90.	An improved wellhead casing hanger for suspension of successive casing strings with particularly small annular spacings having an adapter sleeve of double wall construction which is utilized with a load bearing shoulder on the inside of the inner member for receiving a conventional expanding type hanger, with the annulus between the inner and outer walls providing an improved fluid return path without restricting the bore of the sleeve, packoff for sealing the annulus at the appropriate time and an installation tool.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of and claims priority from co-pending U.S. Application having Ser. No. 11/728,461, filed Mar. 26, 2007, the full disclosure of which is hereby incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The disclosure herein relates generally to the field of severing a tubular member. More specifically, the present disclosure relates to an apparatus for cutting downhole tubulars. Yet more specifically, described herein is a method and apparatus for optimizing cutting tubulars wherein lubrication is maintained between the cutting member and the tubular. [0004] 2. Description of Related Art [0005] Tubular members, such as production tubing, coiled tubing, drill pipe, casing for wellbores, pipelines, structural supports, fluids handling apparatus, and other items having a hollow space can be severed from the inside by inserting a cutting device within the hollow space. As is well known, hydrocarbon producing wellbores are lined with tubular members, such as casing, that are cemented into place within the wellbore. Additional members such as packers and other similarly shaped well completion devices are also used in a wellbore environment and thus secured within a wellbore. From time to time, portions of such tubular devices may become unusable and require replacement. On the other hand, some tubular segments have a pre-determined lifetime and their removal may be anticipated during completion of the wellbore. Thus when it is determined that a tubular needs to be severed, either for repair, replacement, demolishment, or some other reason, a cutting tool can be inserted within the tubular, positioned for cutting at the desired location, and activated to make the cut. These cutters are typically outfitted with a blade or other cutting member for severing the tubular. In the case of a wellbore, where at least a portion of the casing is in a vertical orientation, the cutting tool is lowered into the casing to accomplish the cutting procedure. BRIEF SUMMARY OF THE INVENTION [0006] Disclosed herein is a cutting tool and method wherein lubrication is delivered during cutting. The system employs a rotating blade and a lubrication system for dispensing lubrication between the blade's cutting surface and the tubular to be cut. Optionally an isolation material may be included for retaining the lubrication in the cutting region. An example of a cutting tool includes a housing, a cutting member having a stowed position within the housing and a cutting position in cutting contact with the tubular, lubricant stored in a reservoir in the housing, a lubricant dispensing system having an inlet in fluid communication with the reservoir, an exit on the lubricant dispensing system that is sealed when the cutting member is in the stowed position, and open when the cutting member is in the cutting position, so that when the cutting member is in the cutting position lubricant can flow from the reservoir, through the lubricant dispensing system, and from the exit into the space between the cutting member and the downhole tubular. The cutting tool may optionally have a pressure source in pressure communication with the lubricant in the reservoir, so that when the exit on the lubricant dispensing system is open the lubricant is urged from the reservoir and out the exit. The cutting tool can also further include isolation material in a reservoir in the housing, a selectively openable passage between the reservoir and annulus between the cutting tool and the tubular, so that when the passage is opened the isolation material flows from the reservoir into the annulus to form a barrier hindering the lubricant from flowing away from the area where the cutting member contacts the tubular. A conduit may be in the cutting tool between the inlet and exit; also included can be a fastener coaxially coupled with the cutting member, wherein the exit mates with the fastener when the cutting member is in the stowed position to form a seal at the exit, and when the cutting member is in the cutting position the fastener is moved away from the exit thereby removing the seal from the exit allowing lubricant to flow through the conduit and out of the exit. A sealing plug may be slidingly disposed within the conduit that forms a seal in the conduit along its length and is pushed from the conduit by the lubricant when the seal is removed. The lubricant dispensing system can be a frangible conduit having an inlet in fluid communication with the reservoir, wherein the conduit is positioned so that when the cutting member moves from its stowed position to its cutting position it cutting contacts the frangible conduit to form an opening for lubricant to exit. Alternatively, the lubricant dispensing system includes a conduit depending from the exit, a sealing surface in the conduit, a seal element in the conduit in selective sealing engagement with the sealing surface, a portion of the seal element protruding past the exit and in the cutting member path as it moves from its stowed to cutting position, so that when the cutting member moves into its cutting position it contacts the seal element to push it away from the sealing surface to provide a fluid communication path between the reservoir and the exit. The cutting tool can be suspended from the surface on a conveyance member attached to the housing; a motor may be included in the housing coupled to the cutting member, and an anchor can be coupled with the housing having a deployed position in anchoring contact with the tubular. An electrical power supply can be provided at the surface connected to the conveyance member and a conducting member included between the conveyance member and the motor, so that power from the electrical power supply powers the motor. [0007] Also disclosed herein is a method of cutting a downhole tubular that includes providing a tubular cutting device that includes a body, a cutting member moveable along a path from a stowed position within the body to a cutting position outside of the body, a supply of lubricant in the body, a lubricant dispensing system in fluid communication with the lubricant having a selectively openable exit, deploying the cutting device within the tubular; contacting the portion of the dispensing system with the cutting member by moving the cutting member from the stowed position to the cutting position, selectively opening the dispensing system exit with the cutting member so that lubricant flows from the exit and in the space adjacent the portion of the tubular to be cut, rotating the cutting member, and contacting the tubular with the rotating cutting member with the lubricant between the cutting member and the tubular. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING [0008] FIG. 1 . is a side view of an embodiment of a cutting tool in a tubular. [0009] FIG. 2 is a side view of an alternative embodiment of a cutting tool in a tubular. [0010] FIG. 3 is a side view of an alternative embodiment of a cutting tool in a tubular. [0011] FIG. 4 a is a side view of a cutting tool having a lubrication system. [0012] FIG. 4 b is a magnified side view of a cutting tool with a lubrication system. [0013] FIG. 5 is an overhead view of a cutting blade having lubrication delivery ducts. [0014] FIG. 6 is a partial cut away view of a cutting tool disposed in a cased wellbore. [0015] FIG. 7 depicts in a perspective view a cutting tool with a lubricant sub. [0016] FIGS. 8A , 8 B, 9 A, and 9 B depict in side schematic view a cutting member extending towards a cutting position and opening a discharge port for a lubricant. [0017] FIG. 10 illustrates a side schematic view of an example of a cutting member moving into contact with a frangible conduit. [0018] FIGS. 11 and 11A provide side schematic depictions of a cutting member moving into activating contact with a lubricant dispensing system. [0019] FIGS. 12A and 12B depict in side sectional views an example of a lubricant dispensing system for use with a cutting tool. [0020] FIG. 13 provides a perspective view of an example of a cutting tool with a cover. [0021] FIGS. 14A-14C and 15 A- 15 B depict in perspective and sectional views an example of a lubricant dispensing system for use with a cutting tool. DETAILED DESCRIPTION OF THE INVENTION [0022] The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be through and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. [0023] It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. Accordingly, the improvements herein described are therefore to be limited only by the scope of the appended claims. [0024] Described herein is a method and apparatus for cutting and severing a tubular. While the apparatus and method described herein may be used to cut any type and length of tubular, one example of use involves severing tubing disposed within a wellbore, drill pipe, wellbore tubular devices, as well as wellbore casing. One embodiment of a cutting tool 10 as described herein is shown in side partial cut away view in FIG. 1 . In this embodiment, the cutting tool 10 comprises a body 11 disposed within a tubular 5 . As noted, the tubular 5 may be disposed within a hydrocarbon producing wellbore, thus in the cutting tool 10 may be vertically disposed within the wellbore tubular. Means for conveying the cutting tool 10 in and out of the wellbore include wireline, coiled tubing, slick line, among others. Other means may be used for disposing the cutting tool 10 within a particular tubular. Examples of these include drill pipe, line pigs, and tractor devices for locating the cutting tool 10 within the tubular 5 . [0025] Included within the body 11 of the cutting tool 10 is a cutting member 12 shown pivotingly extending out from within the body 11 . A lubricant 18 is shown (in cross hatch symbology) disposed in the cutting zone 22 formed between the outer surface of the tool 10 and the inner surface 6 of the tubular 5 . For the purposes of discussion herein, the cutting zone 22 is designed as the region on the inner circumference of the tubular, as well as the annular space between the tool and the tubular proximate to the portion of the tubular that is being cut by the cutting tool. Examples of lubricants include hydrogenated polyolefins, esters, silicone, fluorocarbons, grease, graphite, molybdenum disulfide, molybdenum sulfide, polytetrafluoroethylene, animal oils, vegetable oils, mineral oils, and petroleum based oils. [0026] Lubricant 18 inserted between the cutting member 12 and the inner surface 6 enhances tubular machining and cutting. The lubricant 18 may be injected through ports or nozzles 20 into the annular space between the tool 10 and the tubular 5 . These ports 20 are shown circumferentially arranged on the outer surface of the tool housing 11 . The size and spacing of these nozzles 20 need not be arranged as shown, but instead can be fashioned into other designs depending upon the conditions within the tubular as well as the type of lubricant used. As discussed in more detail below, a lubricant delivery system may be included with this device for storing and delivering the lubricant into the area between the cutting member and the tubular inner surface 6 . In many situations when disposing a cutting tool within a tubular, especially a vertically oriented tubular, lubricants may be quickly drawn away from where they are deposited by gravitational forces. Accordingly, proper lubrication during a cutting sequence is optimized when lubrication is maintained within the confines of the cutting zone 22 . [0027] Additional ports 16 are shown disposed on the outer surface of the housing 11 for dispensing an isolation material 14 into the space between the tubular 5 and the tool 10 . The lubricant port 20 location with respect to the isolation port 16 location enables isolation material 14 to be injected on opposing sides of the lubricant 18 . Isolation material 14 being proximate to and/or surrounding the lubricant 18 retains it within or proximate to the cutting zone 22 . Referring again to FIG. 1 , isolation material 14 is disposed in the annular space between the tool 10 and the tubular 5 and on opposing ends of the lubricant 18 . Thus the isolation material should possess sufficient shear strength and viscosity to retain its shape between the tool 10 and the tubular and provide a retention support for the lubricant 18 . [0028] Examples of isolation materials include a gel, a colloidal suspension, a polysaccharide gum, xanthan gum, and guar gum. One characteristic of suitable isolation material may include materials that are thixotropic, i.e. they may change their properties when external stresses are supplied to them. As such, the isolation material should have a certain amount of inherent shear strength, high viscosity, and surface tension in order retain its form within the annular space and provide a retaining force to maintain the lubricant in a selected area. Thus, as shown in FIG. 1 , the presence of the isolating material on opposite sides of the lubricant helps retain the lubricant within the cutting zone. [0029] An alternative embodiment of a cutting tool 10 A within a tubular 5 is provided in side partial cross sectional area in FIG. 2 . In this embodiment, nozzles 16 are shown circumscribing the body 11 A outer surface along a single axial location on the tool 10 A. Optionally, in this situation, the nozzles 16 could be disposed on a side of the lubrication nozzles 20 opposite the cutting member 12 . [0030] Shown in a side partial sectional view in FIG. 3 is another embodiment of a cutting tool 10 B coaxially deployed within a tubular 5 . In this embodiment the cutting member 12 B is a straight blade affixed to a portion of the body 11 B. Although in this embodiment a single set of nozzles 16 is shown for disposing isolation material 14 into the annular space between the cutting tool 10 B and the inner surface 6 of the tubular 5 , multiple sets of nozzles can be included with this embodiment along the length of the cutting tool 10 B. As shown, the lubricant 18 has been injected into the tubular 5 between the tool 10 B and the tubular inner surface 6 . Thus, the cutting zone 22 includes lubrication for enhancing any machining or cutting by the tool 10 B. Isolation material 14 is also injected into the annular space between the tool 10 B and the tubular thereby providing a retaining support for the lubricant 18 . [0031] Another embodiment for delivering lubrication to a cutting surface is provided in FIGS. 4A and 4B . Here an example is provided of delivering a lubricant 18 to the cutting surface of a cutting blade by installing conduits within the blade itself. Shown in side partial sectional view in FIG. 4A is a cutting tool 10 C within a tubular 5 having a blade like cutting member 12 C radially extending from the body 11 C. Rotating the cutting tool 10 C while urging the cutting member 12 C into contact with the inner surface 6 cuts into the tubular 5 , and eventually severs the tubular 5 . Lubricant 18 is provided within a lubricant reservoir (not shown) disposed in the body 11 C. The reservoir is in fluid communication with the cutting member 12 C via supply line 24 shown extending into the cutting member 12 C. Lubricant 18 flows from the reservoir through the supply line 24 and exits the cutting member 12 C through a nozzle exit 26 formed at the supply line 24 terminal end. When discharged from the supply line 24 , the lubricant 18 enters the annular space between the cutting member 12 C and the inner surface 6 . This places the lubricant 18 on the cutting surface 27 of the cutting member 12 C reducing cutting friction thereby enhancing cutting operations. Lubricant 18 may be constantly supplied out into the nozzle exit 26 during a tubular 5 cutting procedure. [0032] FIG. 5 provides an overhead view of one example of a cutting member 12 C that includes a blade 29 having conduits formed within its surface for delivering lubricant 18 to a cutting surface. In this embodiment, the cutting member 12 C includes inlays 28 on the blade 29 . Rotating the blade 29 about its axis A X and contacting a tubular with the moving inlays 28 can cut and sever a tubular. Lubricant supply lines 30 , shown in dashed outline, extend linearly along the blade 29 in opposite directions from the blade axis A X . The supply lines 30 terminate at exit nozzles 31 proximate each inlay 28 . Optimization of machining or cutting a tubular can occur by injecting lubricant from the exit nozzles 31 so lubricant is on the cutting surface during cutting. Optionally a nozzle could be formed on an inlay 28 so that lubricant 18 is added during the entire cutting sequence and is present between the cutting blade 29 and the cutting surface. For the purposes of discussion herein, cutting surface can be a surface in cutting contact, this includes the tubular inner surface 6 where it is being contacted by a cutting member as well as any portion of a cutting member or blade contacting a tubular during cutting. [0033] FIG. 6 provides a partial side cut away view of an embodiment of a cutting system used in cutting a tubular 7 . In this embodiment a cutting tool 10 D is shown deployed from a conveyance member 8 into a cased wellbore 4 that intersects a subterranean formation 2 . The tubular 7 is coaxially disposed within the wellbore casing. Optionally, the cutting tool 10 D may be employed for cutting the wellbore casing and used in the same fashion it is used for cutting the tubular 7 . Examples of means used in deploying the tool 10 D in and out of the wellbore 4 by the conveyance member 8 include wireline, slick line, coil tubing, and any other known manner for disposing a tool within a wellbore. Shown included with the cutting tool 10 D is a controller 38 , a lubricant delivery system 40 , an isolation material delivery system 46 , and a cutting member 12 . The controller 38 , which may include an information handling system, is shown integral with the cutting tool 10 D and may be used for its control. The controller 38 may be configured to have preset commands stored therein, or can receive commands offsite or from another location via the conveyance member 8 . An optional anchoring system 32 is shown having anchor legs extending outward from the cutting tool 10 D into anchoring contact with the tubular 7 inner surface. [0034] The lubricant delivery system 40 can be employed to deliver lubricant 18 within the space between the cutting member 12 and tubular 7 . The delivery system 40 shown includes a lubricant pressure system 42 in communication with a lubricant reservoir 44 . The pressure system 42 is adapted for conveying lubricant 18 from within the reservoir 44 through the tool 10 D and into the annular space between the cutting tool 10 D and the tubular 7 and adjacent the cutting member 12 . The pressure system 42 may be spring loaded, a motor driven pump, or include pressurized gas. [0035] Further depicted with the cutting tool 10 D of FIG. 6 is an isolation material pressure supply 48 and an isolation material reservoir 50 that are included with the isolation material delivery system 46 . The isolation material pressure supply 48 , which can have a pump, spring loaded device, or compressed gas, may be used in urging isolation material 14 from within the isolation material reservoir 50 and out into the annular space between the tool 10 D and the tubular 7 . It should be pointed out that the isolation material 14 and lubricant 18 can be simultaneously ejected from the cutting tool 10 D. Optionally either the isolation material 14 or lubricant 18 may be delivered into the annular space before the other in sequential or time step fashion. As far as the amount of lubricant 18 or isolation material 14 delivered, it depends on the cutting tool 10 D and/or tubular 7 dimensions; it is believed it is well within the capabilities of those skilled in the art to design a system for delivering a proper amount of lubricant 18 as well as isolation material 14 . [0036] As shown with the embodiment of FIG. 6 , the cutting member is in a cutting sequence for cutting the tubular 7 and isolation material 14 is shown retaining a quantity of lubricant 18 adjacent the cutting member 12 thereby maintaining the lubricant 18 in the space between the cutting member and the tubular 7 . A controller 34 disposed at surface may be employed for relaying commands to or otherwise controlling the cutting tool 10 D. The controller 34 may be a surface truck (not shown) disposed at the surface as well as any other currently known or later developed manner of controlling a wellbore tool from the surface. Included optionally is an information handling system 36 that may be coupled with the controller 34 either in the same location or via some communication either wireless or hardwire. Also illustrated schematically is a power supply 35 shown disposed on the surface above the wellbore 4 and in communication with the conveyance member 8 . The power supply 35 can selectively provide power to the cutting tool 10 D via the conveyance member 8 that can be used for controls and/or motors within the tool 10 D. [0037] It should be pointed out that the exit nozzles can have the same cross sectional area as the supply lines leading up to these nozzles, similarly other types of nozzles can be employed, such as a spray nozzle having multiple orifices, as well as an orifice type arrangement where the cross sectional area at the exit is substantially reduced to either create a high velocity stream or to atomize the lubricant for more dispersed application of a lubricant. [0038] Referring now to FIG. 7 , provided therein is a side perspective and partial sectional view of an embodiment of a cutting tool 52 . The cutting tool 52 shown is a generally elongated member having a cylindrical outer body or housing 54 . Within the housing 54 is a motor 56 coupled to a circular cutting member 58 on its lower end. A fastener 60 couples on the cutting member 58 lower surface coaxial with the cutting tool 52 . The fastener 60 may be a nut that is screwed onto a shaft (not shown) extending from the motor 56 . Optionally, a gearing system (not shown) may mechanically connect the motor 56 and cutting member 58 . [0039] Below the cutting member 56 the housing 54 tapers into a frusto-conical section to define a nose portion 62 . A bore 64 is shown axially formed through the nose portion 62 and in alignment with the fastener 60 . A cylindrically shaped nozzle 66 is disposed in the bore 64 having an upper end in contact with the fastener 60 lower surface. The nozzle 66 lower most end juts into a cylindrically shaped lubricant sub 70 that is attached along the conically contoured nose portion 62 outer surface. The lubricant sub 70 is shown in sectional view as a generally hollow member having on its upper end a cylindrically shaped plug 72 that abuts the nose portion 62 lower end. A ferrule 74 shown coaxially within the plug 72 registers with a passage 68 coaxially formed through the nozzle 66 . A reservoir 76 is defined within an open space in the sub 70 that is below the plug 72 . Lubricant may be stored in the reservoir 76 for injection between the cutting member 58 and a tubular inner surface. As noted above, injection of the lubricant onto a cutting surface enhances the cutting deficiency of a cutting tool. [0040] In the embodiment of FIG. 7 a pressure source is provided within the lubricant sub 70 depicted as a combination of a piston 78 and spring 80 . The piston 78 illustrated is a cylindrical element defining the reservoir 76 lower periphery. The spring 80 , which coils helically along the inner circumference of the sub 70 , has a lower end in contact with the lower most surface of a sub 70 in an upper end in contact with the piston 78 . Thus as lubricant is expelled from the reservoir 76 the spring 80 expands to urge the piston 76 upwards in the direction of the plug 72 . Other pressure means may be employed, such as compressed gas, an expandable bladder, and selectively openable ports adapted to receive wellbore fluid therein. [0041] FIGS. 8A and 8B provide an enlarged view of a portion of the cutting tool 52 where it couples with the lubricant sub 70 . In these views shown is the passage 68 coaxially formed within the nozzle 66 and how it registers with a dispensing line 75 coaxially formed through the ferrule 74 . The combination of the dispensing lines 75 and passage 68 form a conduit adapted for flowing lubricant within the reservoir 76 out into the cutting space between the cutting member 58 in the tubular. More specifically, in FIG. 8A the nozzle 66 upper end is depicted in sealing contact with the fastener 60 bottom blocking the passage 68 exit. [0042] Shown in FIG. 8B the cutting member 58 is moving into a cutting position by pivoting radially outward breaching sealing contact between the fastener 60 and nozzle 66 exit. Therefore lubricant within the reservoir 76 now has a clear path from the nozzle 66 exit and can flow from the reservoir, through the conduit, and out of the nozzle 66 exit. Once past the nozzle 66 exit the lubricant can make its way to between the cutting member 58 and tubular. A resilient member 69 is shown in the space between the nozzle 66 and ferrule 74 that provides an outwardly urging force maintaining the sealing contact between the nozzle 66 exit and fastener 60 . In an example the resilient member may be a spring. [0043] FIGS. 9A and 9B respectively represent side schematic depictions of a cutting member 58 in a stowed position within the housing 54 and in a cutting position in cutting contact with a tubular. The cutting tool 52 embodiments shown in FIGS. 9A and 9B includes a dispensing line 75 representing a conduit for communicating fluid between the reservoir 76 and lubricant exit. The dispensing line 75 exit is shown in sealing contact with the fastener 60 lower surface. Further provided in the embodiments of FIGS. 9A and 9B is a sealing plug 77 slidingly disposed within the dispensing line 75 . The presence of the sealing plug 77 enhances the pressure seal between the lubricant within the reservoir 76 and ambient the dispensing line 75 . Referring now to FIG. 9B , the cutting member 58 and fastener 60 have moved radially outward from the tool 52 axis A X thereby removing contact between the exit from the dispensing line 75 and fastener 60 . This opens the dispensing line exit 75 allowing the flow of lubricant from the reservoir 76 , represented by arrows, through the dispensing line 75 and into the ambient space, where it can make its way or be directed into the space between the cutting element and tubular. [0044] A schematic of an alternate cutting tool 52 A is provided in a side sectional view in FIG. 10 . In this embodiment, a lubricant reservoir 76 within the housing 54 is shown containing lubricant L providing a lubricant supply. A dispensing line 75 A provides fluid communication between the lubricant reservoir 76 and a frangible tube 82 shown disposed in the path between the cutting member 58 stowed position and its cutting position. The frangible tube 82 is formed from a material that can be ruptured or otherwise severed by cutting contact with the cutting member 58 . Moreover, the frangible tube 82 has a sealed terminal end. In the embodiment of FIG. 10 , the end is attached to a solid portion of the body 54 . Optionally, the frangible tube 82 can stand freely in the cutting member 58 path and have a closed end rather than attached to the body 54 . In the embodiment of FIG. 10 , the cutting member 58 which is in cutting rotation, cuts the frangible tube 82 to form an opening. The opening cut into the frangible tube 82 provides an exit for lubricant L within the reservoir 76 to be dispensed into the space outside of the housing 54 and onto the surface of the tubular to be cut by the cutting member 58 . [0045] Shown in a side schematic partial sectional view in FIG. 11 is an alternate example of a cutting tool 52 B in accordance with the present disclosure. In the embodiment of FIG. 11 a dispensing unit 86 is shown in fluid communication with a dispensing line 75 B connected on an upstream end to the lubricant reservoir 76 . Contact between the cutting member 58 and a protruding portion of the dispensing unit 86 opens a fluid path between the lubricant reservoir 76 and the area outside the housing 54 . FIG. 11A shows in a side sectional view, an enlarged view of the dispensing unit 86 and its interaction with the cutting member 58 . The dispensing unit 86 includes a cylindrical hollow outer housing 88 , a spherical seal plug member 90 within the housing 88 , an annular lip 91 on the exit portion of the housing 88 , and a spring 92 in urging contact against the seal plug member 90 on the side opposite the annular lip 91 . [0046] Referring back to FIG. 11 , a portion of the seal plug member 90 protrudes past the remaining elements in the dispensing unit 86 . In this configuration, the seal plug member 90 contacts the inner radius of the annular lip 91 urged upward by the spring 92 to create a sealing surface between the seal plug member and annular lip 91 . The dispensing unit 86 shown is configured so that a portion of the seal plug member 90 protrudes into the cutting member 58 path. Thus, as the cutting member 58 moves into its cutting position from its stowed position, it contacts the seal plug member 90 pushing it further inside the housing 88 and depressing the spring 92 . This unseats the seal plug member 90 from the annular lip 91 allowing lubricant from within the reservoir 76 to exit from within the housing 54 . [0047] Shown in a side sectional view in FIGS. 12A and 12B is another embodiment of a lubricant to cutting surface delivery system. With reference to FIG. 12A , a bore 64 C extends through the nose portion 62 between the reservoir 76 and cavity 63 within the cutting tool 52 C. A threaded plug 65 is fastened within an end of the bore 64 C adjacent the reservoir 76 . An elongated piston like sealing plug 77 C is slidingly provided within the bore 64 C having a portion shown extending outside the bore 64 C and into the cavity 63 . The sealing plug 77 C outer surface is scored on its outer circumference to form a notch 79 and its upper end terminates at the fastener 60 lower surface. An extension 61 is shown depending downward from the fastener 60 lower surface to below the sealing plug 77 C upper end. [0048] Both the bore 64 C and sealing plug 77 C diameters transition from a larger to a smaller diameter. In the configuration of FIG. 12A , the respective diameter transitions are at different locations to form an annular space 73 around a portion of the smaller diameter section of the sealing plug 77 C. Also in the bore 64 C is a spring 67 shown between the threaded plug 65 and sealing plug 77 C that forces the sealing plug 77 C upper end against the fastener 60 . Also included in this embodiment is a passage 71 bored through the nose portion 64 C with an end in fluid communication with the reservoir 76 and an opposite end connecting to the dispensing line 75 C. The dispensing line 75 C has an exit proximate the cutting member 58 . The passage 71 intersects the bore 64 C along a portion in which the plug 77 C is disposed. In the embodiment of FIG. 12A , a seal is formed along the area where the sealing plug 77 C contacts the passage 71 that blocks fluid communication between the reservoir 76 and dispensing line 75 C. [0049] As the blade 58 is rotated and pivoted radially outward from the cavity 63 , the attached extension 61 collides with the sealing plug 77 C and applies a sufficient moment arm to fracture the sealing plug 77 C along the notch 79 . Referring now to FIG. 12B , removing the portion of the sealing plug 77 C above the notch 79 , allows the spring 67 to expand and upwardly urge the remaining section of sealing plug 77 C. This unseats the seal between the sealing plug 77 C and passage 71 thereby allowing lubricating fluid within the reservoir 76 to be communicated through the passage 71 , to the dispensing line 75 C, and then delivered to a cutting surface. The sealing plug 77 C is prevented from being ejected from the bore 64 C by contact between the diameter transitions on the bore 64 and sealing plug 77 C, thus eliminating the annular space 73 . [0050] The present disclosure further includes using a cutting tool with a lubricant to cut tubulars with increased chrome amounts, as well as alloying elements such as nickel, vanadium, molybdenum, titanium, silicium. This method is also applicable to cutting in environments with water, salt water, and drilling fluids. [0051] A cover 55 may be provided with an embodiment of the cutting tool 52 D for retaining grease within the tool 52 D. Shown in perspective view in FIG. 13 , the cover 55 envelops a portion of the cavity 63 where the blade 58 is deployed. The cavity 63 can be packed with grease prior to being deployed and the cover 55 put in place thereby retaining the grease in the cavity 63 and on the blade 58 while the tool 52 D is being lowered downhole. The cover 55 is shown hinged on an end to the housing 54 D so that it can swing open and not impede the blade 58 as it is pivoted radially outward. Selectively opening the cover 55 during cutting enables grease to also migrate to the cutting surface. The cover 55 may be biased, such as with a spring or like member, so that it follows the blade 58 and closes over the cavity 63 as the blade 58 is re-stowed within the housing 54 D). [0052] In an optional embodiment shown in FIGS. 14A-15B , grease and/or lubricant from a reservoir on one side of the cutting blade 58 can be dispensed to an opposite side of the blade 58 . Shown in a partial sectional perspective in FIG. 14A , a section of the nose portion 62 E of the cutting tool 52 E projects past the cutting blade 58 having an end terminating at a blade mount 93 . The blade mount 93 shown houses a portion of a shaft 94 for rotating the cutting blade 58 and gears for driving the shaft 94 . A pivot shaft 95 couples within the blade mount 93 , that when rotated pivots the blade mount 93 and blade 58 . In the cutting tool 52 E example of FIGS. 14A-14C , when the tool 52 E is being deployed and the cutting blade 58 is stowed, the sealing plug 77 E end opposite the spring 73 is urged against the fastener 60 by the spring 73 . Grease and/or lubricant may be introduced into the reservoir 76 E via an inlet port 83 disposed in a lateral bore 85 formed radially inward into the nose portion 62 E. An axial bore 87 intersects the lateral bore 85 to communicate grease and/or lubricant injected into the port 83 to the reservoir 76 E. The lateral bore 85 as shown intersects the passage 71 E. [0053] A channel 81 is provided on the blade mount 93 on a side of the cutting blade 58 opposite the reservoir 76 E ( FIG. 14B ). The channel 81 registers with the passage 71 E discharge side and extends along the blade mount 93 . The other end of the channel 81 terminates between the blade 58 outer periphery and mid section in communication with the side of the blade 58 opposite the reservoir 76 E. Thus lubricant and/or grease can be dispensed onto the cutting blade 58 by flowing it from reservoir 76 E, into the passage 71 E, and through the channel 81 . FIG. 14C provides a sectional view of the cutting tool 52 E taken along its axis on the reservoir 76 C side of the cutting blade 58 . The section of the nose portion 62 E extending past the blade 58 has a width that tapers along its circumference thereby forming a crescent shape. The wider section of the nose portion 62 E is disposed proximate and perpendicular to the pivot shaft 95 . The wider section also includes the passage 71 E discharge; thus as shown, the passage 71 E discharge is proximate to the pivot shaft 95 . [0054] FIGS. 15A and 15B provide side and axial sectional views of the cutting tool 52 E in a cutting position. The section of the nose portion 62 E extending past the blade 58 encircles less than half the blade 58 ; this leaves an open space allowing the blade 58 to pivot radially outward into cutting contact with a tubular. Because the passage 71 E discharge is aligned with the pivot shaft 95 , the passage 71 E remains registered with the channel 81 while the blade mount 93 and blade 58 are being pivoted into cutting contact. Thus as the blade 58 spins during a cutting procedure, grease and/or lubricant can be deposited on its side and delivered to the cutting surfaces such as by the centrifugal force of the blade 58 . [0055] The improvements described herein, therefore, are well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While presently preferred embodiments have been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present disclosure and the scope of the appended claims.	The tubular cutting tool for severing downhole tubulars, the tool having a drive system, a pivoting system, a cutting head, a cutting member, and a lubricant delivery system. Cutting may be accomplished by rotatingly actuating the cutting head with an associated motor and extending the cutting member away from the cutting head. The lubricant delivery system lubricates the respective contacting surfaces of the cutting member and the tubular and is actuated when the cutting member extends from the cutting head.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATION This is a continuation of U.S. patent application Ser. No. 11/817,292, filed Aug. 28, 2007, now U.S. Pat. No. 7,617,889 which is the U.S. National Phase Application of International Application No. PCT/US2006/042740, filed Oct. 31, 2006, which was published in English under PCT Article 21(2) and which claims the benefit of U.S. Provisional Application No. 60/733,860, filed Nov. 3, 2005. Each of the referenced applications is incorporated herein in its entirety. FIELD This application relates to drilling equipment, and in particular to an improved construction of a fluid-operated drilling tool. BACKGROUND Known types of fluid-operated drilling tools, particularly “down-the-hole” rock drilling tools, generally have one end connected to a source of pressurized fluid (referred to here as the proximal end) and an opposite distal or working end with a reciprocating bit that is controlled to strike material to be drilled or removed with high force. In a conventional rock drilling tool, the source of pressurized fluid, which is typically compressed air or other gas, is connected to a backhead or top sub at the proximal end of the tool by a pressure fitting. A hollow wear sleeve is attached by a threaded connection to the backhead and extends distally to form the exterior surface or shank of the tool. Within the wear sleeve, there is a distributor with a check valve that selectively supplies pressurized fluid to move the piston. Typically, the distributor is secured in place by its attachment to an interior surface of the wear sleeve. According to one known approach, the distributor is received within the bore of an inner cylinder, and the inner cylinder has a surrounding retaining ring that is received in a circumferential groove formed in the interior surface of the wear sleeve. Over time, it becomes necessary to remove the distributor, e.g., to repair or replace it, to replace the wear sleeve to which it is attached and/or to access other components within the wear sleeve, e.g., the piston. In conventional drilling tools, uncoupling the distributor from the wear sleeve is difficult. For example, it can be difficult to access the retaining ring and disengage it from the wear sleeve and/or the distributor. In conventional drilling tools, some of the passageways for the pressurized fluid have reduced areas and/or other types of restrictions that decrease flow velocity and efficiency. Some of the passageways extend between coaxially positioned components, and some are formed at least in part by channels, grooves, openings, etc., formed in walls of the components. In the operation of some drilling tools, such as a down-the-hole rock drilling tool, the tool is designed such that when the bit encounters a very low resistance during operation, such as when the bit encounters a void in the material being drilled, the bit is extended to a “drop open” position and further movement of the bits is stopped. In the way, the possibility for damage to the tool or to the operation is minimized. It would be advantageous to decrease the transition time for changing from a normal operating position to the drop open position. In addition, the speed at which the tool transitions between other phases of operation is affected by the piston area. It would be advantageous to reduce the transition times between other phases of operation to improve overall efficiency. SUMMARY Described herein are embodiments of a backhead and drill assembly with a backhead that address some of the problems associated with current drilling tools. According to one implementation, a portion of a drill assembly operated by a supply of compressed fluid comprises a backhead with an integrated piston, a hollow elongate wear sleeve and a piston. The backhead has a proximal end connectible to the supply, an axial bore and an open distal end having the integrated cylinder portion defined therein. The backhead has passages extending between the axial bore and outer surface of the backhead. The hollow elongate wear sleeve has a proximal end to which the backhead is coupled and into which the distal end of the backhead is received. The piston is housed by the wear sleeve and has a proximal end shaped to fit within the integrated cylinder portion of the backhead. The piston is slidably movable along the wear sleeve and the integrated cylinder portion in response to compressed fluid conveyed through the backhead. An intake flow path for an intake flow of compressed fluid in the drilling tool extends in a distal direction from the axial bore, through the passages in the backhead, through a space between the backhead and the wear sleeve and into an area between the piston and wear sleeve and into contact with the piston. Advantageously, the intake flow path is free from sharp bends. The intake flow path may be configured so as not to extend through any apertures forcing the intake flow in a radially inward direction. The intake flow path may be configured so as not to require the intake flow to pass inwardly through any openings defined in a sidewall of the backhead. The drill assembly may comprise a distributor positioned at least partially within the axial bore between the proximal end and the distal end, the distributor being removably secured to the backhead by a securing member accessible from an exterior surface of the backhead and including a check valve that is opened to allow the intake flow from the supply. The distributor can comprise a check valve having a sealing member, a biasing member that biases the sealing member to a closed position and a distally extending guide portion. The drill assembly may comprise a chuck coupled to a distal end of the wear sleeve and capable of receiving a drill bit and being movable in response to contact from the piston. According to other embodiments, a portion of a drill assembly operated by a supply of compressed fluid comprises a backhead having a proximal end connectible to the supply, an axial bore and an open distal end having defined therein an integrated cylinder portion shaped to receive a piston member, and a distributor positioned at least partially within the axial bore between the proximal end and the distal end, the distributor being removably secured to the backhead by a securing member accessible from an exterior surface of the backhead. The securing member can comprise a laterally extending pin inserted through at least one opening in the backhead. The securing member can comprise at least two laterally extending pins, each of the pins being inserted through one of a corresponding number of spaced-apart openings in the backhead. The backhead can include an externally threaded portion to which a wear sleeve can be attached, and the securing member can comprise a laterally extending pin inserted through at least one opening in the backhead in the area of the threaded portion. According to other embodiments, a portion of a drill assembly operated by a supply of compressed fluid comprises a backhead having a proximal end connectible to the supply, an axial bore and an open distal end having defined therein an integrated cylinder portion, the backhead having passages extending between the axial bore and outer surface of the backhead, a hollow elongate wear sleeve having a proximal end to which the backhead is coupled and into which the distal end of the backhead is received, and a piston housed by the wear sleeve and having a proximal end shaped to fit within the integrated cylinder portion of the backhead, the piston being slidably movable along the wear sleeve and the integrated cylinder portion in response to compressed fluid conveyed through the backhead. When the drill assembly is in a drop open position, a proximal end of the piston is spaced apart from the integrated cylinder portion in the distal direction and an open annular space is defined between a proximal end of the piston and the wear sleeve. The piston can have an available piston area subject to pressure tending to move the piston in a distal direction that is about 5% to about 25% greater than the available piston area of a conventional drill assembly of the same outer diameter. In other embodiments, the piston can have an available piston area that is about 8% to about 10% greater than the available piston area of a conventional drill assembly of the same outer diameter. In still other embodiments, the piston can have an available piston area that is at least about 9% greater than the available piston area of a conventional drill assembly of the same outer diameter. According to other embodiments, a portion of a drill assembly operated by a supply of compressed fluid comprises a backhead having a proximal end connectible to the supply, an axial bore and an open distal end having defined therein an integrated cylinder portion, the backhead having passages extending between the axial bore and outer surface of the backhead, a cylinder portion aligned with and in selective fluid communication with the backhead, a hollow elongate wear sleeve surrounding the cylinder portion and connected to the backhead, a piston housed by the wear sleeve and having a proximal end shaped to fit within the cylinder portion, the piston being slidably movable along the wear sleeve and the cylinder portion in response to compressed fluid conveyed through the backhead. When the drill assembly is in a drop open position, a proximal end of the piston is spaced apart from the cylinder portion and the wear sleeve. According to other embodiments, a portion of a drill assembly operated by a supply of compressed fluid comprises a backhead having a proximal end connectible to the supply, an axial bore and an open distal end having defined therein an integrated cylinder portion, the backhead having passages extending between the axial bore and outer surface of the backhead, a hollow elongate wear sleeve having a proximal end to which the backhead is coupled and into which the distal end of the backhead is received, and a piston housed by the wear sleeve and having a proximal end shaped to fit within the integrated cylinder portion of the backhead, the piston being slidably movable along the wear sleeve and the integrated cylinder portion in response to compressed fluid conveyed through the backhead. An intake flow path for an intake flow of compressed fluid in the drilling tool extends in a distal direction from the axial bore, through the passages in the backhead, through a space between the backhead and the wear sleeve and into an area between the piston and wear sleeve and into contact with the piston, and a filling flow path extends in the proximal direction from the area between the piston and the wear sleeve, along the piston and between the piston and the backhead into a space proximal of the proximal end of the piston. Advantageously, a separation is maintained between the intake flow path and the filling flow path in the area between the piston and the wear sleeve. The distal end of the backhead can have a circumferential wall configured to guide the filling flow flowing in the proximal direction along an inner surface of the wall and configured to guide the intake flow flowing in the distal direction along an outer surface of the wall, the intake flow and the filling flow being separated from each other by the wall. The foregoing and other features and advantages will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a fluid-operated drilling tool showing a new backhead, a distributor, a piston, a wear sleeve, a chuck, and a bit and bit retaining rings. FIG. 2 is an enlarged exploded perspective view of the backhead and distributor assembly of FIG. 1 . FIG. 3 is a sectioned view, in elevation, of the backhead and distributor assembly attached to the wear sleeve and showing a portion of the piston within an inner end of the backhead. FIG. 4 is a perspective view of the backhead and distributor assembly of FIG. 1 . FIGS. 5A and 5B are sectioned views, in elevation, of a conventional fluid-operated drilling tool and a similar tool with the new backhead of FIG. 1 , respectively. FIG. 6 is a perspective view of the backhead and distributor assembly similar to FIG. 2 , except showing a securing member in the form of two pins. FIG. 7 is a sectioned view of the backhead and distributor assembly of FIG. 6 as assembled showing the positions of the two pins. FIG. 8A and FIG. 8B are sectioned views, in elevation, of a conventional fluid-operated drilling tool and a new drilling tool according to this application, respectively, showing the pistons in an impact position. FIG. 9A and FIG. 9B are sectioned views similar to FIG. 8A and FIG. 8B , respectively, except showing the tools in a drop open position. FIGS. 10A and 10B are sectioned views similar to FIG. 8A and FIG. 8B , respectively except showing the tools with the pistons in a top position. FIG. 11A and FIG. 11B are enlarged views of portions of FIG. 8A and FIG. 8B , respectively. FIG. 12A and FIG. 12B are enlarged views of portions of FIGS. 9A and 9B , respectively. FIG. 13A and FIG. 13B are enlarged views of portions of FIG. 10A and FIG. 10B , respectively. DETAILED DESCRIPTION FIG. 1 is an exploded perspective view showing an embodiment of a fluid-operated drilling tool 10 . The major components of the drilling tool 10 are a backhead and distributor assembly 12 at a proximal end of the tool, a wear sleeve 14 , an axially movable piston 16 , and at the distal or working end of the tool, a chuck 18 , a bit 20 and bit retaining rings 22 . In operation, pressurized fluid supplied to the backhead and distributor assembly 12 is used to selectively drive the piston 16 to reciprocatingly translate and to strike the bit 20 , thus causing the bit to exert an impact force on any adjacent material to be drilled. The backhead assembly 12 includes a backhead 24 and a distributor or check valve assembly 26 . The backhead 24 is an elongate member having an exposed proximal end 28 with a connection 30 for attachment to a source of pressurized fluid. The backhead 24 also has a tool receiving portion 32 shaped to receive a tool, e.g., a wrench, to assist in installing and removing the backhead. Adjacent the tool receiving portion 32 is a threaded portion 34 . In the illustrated embodiment, an outer diameter of the backhead is stepped down at a shoulder 33 immediately adjacent the threaded portion 34 . The backhead 24 has an open distal end 36 defining one end of an axial bore 38 . The distributor 26 is fit within the bore 38 and is coupled to the backhead 24 , e.g., by a securing member accessible from an exterior of the backhead, such as a pin 40 , as described below in more detail. The distributor has an elongated guide 42 that extends distally. The piston 16 has a proximal end 44 slidably received in the bore 38 and a distal end 46 slidably received within the wear sleeve 14 . The wear sleeve 14 is removably connected at its proximal end to the backhead and distributor assembly 12 , such as by the threaded portion 34 . The wear sleeve 14 extends distally in the drilling direction, and the chuck 18 is attached at its distal end. The chuck 18 receives the bit 20 , which can be held in place by the bit retaining rings 22 . Referring to FIG. 2 , the distributor 26 has a check valve 48 with a cap-shaped sealing member 50 , a biasing member 52 and stationary member 54 from which the elongated guide 42 extends. The stationary member 54 has a transverse bore 56 sized to receive the pin 40 and a circumferential groove 58 for a seal. Referring to FIG. 3 , the axial bore 38 has an inlet bore segment 60 extending from the proximal end 28 of the backhead 24 that widens into a chamber 62 . At its distal end, the chamber 62 narrows slightly into a necked-down portion defining a check valve receiving area 64 that receives the stationary member 54 of the distributor 26 as shown. At the distal end of the check valve receiving area 64 , the bore 38 is widest and the inner surface thereof defines a cylinder portion 65 within which the proximal end of the piston 16 is slidably received. The stationary member 54 and a seal in the groove 58 seal off the chamber 62 from the bore 38 when the valve is in normal operation. Thus, the check valve receiving area 64 separates the cylinder portion 65 from an inlet area 67 extending proximally of the check valve receiving area 64 . The backhead 24 has at least one through passage 68 which connects the chamber 60 with an axially extending annular space 70 in the wear tube 14 . In a representative embodiment as shown in FIGS. 3 and 4 , there are multiple circumferentially-spaced fluid through passages 68 . Adjacent the distal end 36 , the backhead 24 has circumferentially spaced external grooves 72 that also serve as flow passages between the backhead and the surrounding wear sleeve 14 . As best shown in FIG. 3 , the backhead 24 and wear sleeve 14 can be shaped such that the backhead has a close fit with the wear sleeve adjacent the distal end 36 , and is spaced from the wear sleeve along at least a segment of its length in the area of the annular space 70 . In one embodiment, as best shown in FIG. 4 , the securing member is the pin 40 and the backhead 24 has a transverse opening 66 sized to receive the pin 40 . In the FIG. 4 embodiment, unthreading the backhead 24 exposes the pin 40 and thus allows the distributor 26 to be removed from the backhead 24 . Of course, it is also possible to use a securing member of a type other than a pin. In another embodiment, as best shown in FIG. 6 , the securing member is a pair of pins 41 a and 41 b, each of which can be inserted into a respective one of the openings 67 a , 67 b in the backhead and distributor to removably secure the distributor in place relative to the backhead. The openings 67 a , 67 b are parallel and spaced from each other, extending in a direction transverse to the backhead. As best shown in FIG. 7 , the pins 41 a , 41 b engage opposite sides of a groove 69 formed in the backhead. Of course, it would be possible to use additional pins or elements, and/or to use elements extending only partially through the backhead. FIG. 5A shows a conventional fluid-operated drilling tool 110 having a backhead 124 , an inner cylinder component 113 separate from the backhead 124 and a distributor (or check valve assembly) 126 coupled to the wear sleeve 114 . The backhead 124 is connected to the wear sleeve 114 by a threaded connection. Because the inner cylinder component 113 is also a separate component, it must also be coupled to the wear sleeve 114 . As shown in FIG. 5A , the inner cylinder component 113 is coupled to the wear sleeve 114 by retaining members 115 that expand to fit within a circumferential groove 117 formed in the wear sleeve at a position spaced from its proximal end. With the conventional tool 110 , removing the distributor 126 can be very difficult. The distributor 126 might need to be removed in order to repair or service it, to use it in a new wear sleeve 114 , to replace or service the piston 116 , etc. To remove the distributor 126 , the backhead 124 is unscrewed from the wear sleeve 114 . A tool is then inserted into the wear sleeve 114 in an effort to contact the retaining members 115 and disengage them from the groove 117 . This operation is often very difficult to execute, especially in conditions encountered in the field. With small versions of the tool 110 , a user can sometimes succeed in disengaging the distributor 126 by inverting the wear sleeve 114 and hitting its proximal end against a hard surface. With larger versions of the tool 110 , it is not possible to maneuver the wear sleeve in this way. By comparison, the tool 10 with the new backhead and integrated cylinder as shown in FIG. 5B allows comparatively easy disassembly. The backhead assembly 12 is unscrewed from the wear sleeve 14 , and the distributor 26 can be removed from the backhead 24 by removing the securing member, e.g., removing the pin 40 . With the backhead assembly 12 unscrewed from the wear sleeve 14 , the piston 16 is easily accessible and can be slid out of the wear sleeve 14 . The wear sleeve 14 does not require any complicated machining to form a groove or other undercut retaining feature similar to the groove 117 , and thus is simpler and cheaper to produce. Without these features, the walls of the wear sleeve can be made thinner. Stated differently, for a given external diameter, such as for the 4-inch tools 10 and 110 , the wear sleeve 14 can accommodate a piston 16 having an area at least about 5% greater than the piston 116 , as is described below in greater detail. The new backhead assembly 12 with the integrated distributor 26 conserves operating length in the axial direction. Thus, the tool 10 can have a shorter length than the conventional tool 110 with the same or comparable operating capabilities. As a result, the tool 10 can save costs and is easier to handle. In the following description, a comparison of the flow passageways and piston areas between the conventional drilling tool 110 and the drilling tool 10 is described. FIG. 8A and FIG. 8B are section views in elevation showing the conventional drilling tool and a drilling tool according to an embodiment of this application, respectively, in the impact position, i.e., when the piston has contacted the bit, which in turn exerts an impact on any material with which the bit is in contact. FIGS. 9A and 9B are similar to FIGS. 8A and 8B , but shown the respective drilling tools in a drop open position, when the tools have been brought to rest, such as, e.g., if a void is encountered while drilling. FIGS. 10A and 10B are similar to FIGS. 8A and 8B , but show the respective drilling tools in a position when the piston is at the top of its stroke, i.e., withdrawn in the distal direction. FIG. 11A is an enlarged section view of a portion of the conventional drilling tool 110 shown in FIG. 8A (i.e., in the impact position). As seen in FIG. 11A , the intake of compressed operating fluid, which occurs at one or more times during a complete operating cycle, forces the fluid to follow a flow path 180 through two substantial changes in direction. As a result, the flow's velocity is decreased and thus the time required to complete the intake is lengthened. Specifically, the intake flow path 180 has an upper segment 182 beginning in the passageway 192 between the wear sleeve 114 and the inner cylinder component 113 . Where the flow leaves the passageway 192 , the flow path 180 turns abruptly inward at a first sharp bend 186 and continues through the aperture 194 formed in a wall of the inner cylinder 113 along an intermediate segment 184 . After traveling through the aperture 194 , the flow encounters the solid wall of the piston 116 , so it makes another abrupt turn at a second sharp bend 188 . The flow path 180 then continues in a downward direction along a lower segment 190 in the direction of the arrow, which travels through an inner passageway 196 formed between an inner side of the inner cylinder 113 and the outer wall of the piston 116 , before leading into a region 198 between the piston 116 and the wear sleeve 114 . As shown in the drawing, the intake flow must travel through two substantial bends, each of which is approximately 90 degrees along the mean flow path. As a result, velocity decreases substantially and momentum and energy are lost. Although only a single intake flow path 180 is represented for the portion of the conventional drilling tool 110 shown in FIG. 11A , it should be noted that the conventional drilling tool has four equally spaced apertures 194 , and thus there are four corresponding intake flows following corresponding intake flow paths 180 . FIG. 11B is an enlarged view of a portion of the drilling tool 10 according to this application, taken from FIG. 8B . As seen in FIG. 11B , a comparable intake flow path 80 begins in the area of one of the grooves 72 formed in the backhead 24 and extends in a generally straight direction downward into a region 96 between the piston 16 and the wear sleeve 14 . The flow path 80 as shown in FIG. 11B , which corresponds to one of the grooves 72 appears as a single path. In fact, the flow path 80 comprises the area of all of the grooves 72 positioned around the entire circumference of the backhead 24 . Thus, the many grooves 72 of the drilling tool 10 comprise a greater flow area than the four apertures 194 in the conventional drilling tool 10 . Because the flow path 80 is substantially free of sharp bends, loss of energy due to friction and decreases in velocity are reduced. Stated differently, the flow path 80 is much more energy efficient than the flow path 180 in the conventional drilling tool 110 . In addition, the flow path 80 does not force the intake flow through any apertures or other bounded openings at sharp angles to the flow's primary direction. Also, the intake flow passes along walls (e.g., the outer periphery of the backhead 24 ) rather than through them (compare the conventional drilling tool 110 , where the intake flow must pass through the inner cylinder 113 ). FIG. 12A is an enlarged section view of a portion of the conventional drilling tool 110 shown in FIG. 9A (drop open position). Similarly, FIG. 12B is an enlarged view of a portion of the drilling tool 10 according to this application, taken from FIG. 9B . FIG. 12A shows the piston area, A C , against which the pressurized operating fluid can act to move the piston 116 in the conventional drilling tool 110 . As shown in FIG. 12B , the piston area A N in the drilling tool 10 is greater than the piston area A C . The available piston area includes the area of the upper surface of the piston and other areas exposed to the pressure, which equate to the annular area bounded on the outside by the piston's outer diameter and on the inside by the piston's axial bore. In some embodiments, the area A N exceeds the area A C by about 5% to even about 25%. As an example, a 4-inch diameter drilling tool may have a piston area A C of about 8.36 in 2 , whereas a 4-inch diameter drilling tool according to an embodiment of this application has a piston area A N of about 9.13 in 2 , which is about 9.3% greater. The greater available piston area in the drilling tool 10 allows the pressure acting on the piston 16 to move the piston more quickly, thus increasing the power of the piston. In the drilling tool 10 , when bit is positioned in the drop open position, as best seen in FIG. 9B , the upper end of the piston is spaced away any surrounding surfaces. Because the entire circumferential area around the piston 16 is open, this area fills with pressurized fluid quickly and thus pushes the piston 16 downward to the full drop open position shown in FIG. 9B faster. By way of contrast, in the drilling tool 110 , the piston 116 remains in contact with the surrounding inner cylinder 113 . Thus, pressurized air tending to push the piston 116 downward into the full drop open position shown in FIG. 9A must be forced through the smaller area of the four apertures 194 . In addition, as best seen by comparing FIG. 9A and FIG. 9B , because the drilling tool 10 is designed to function without the upper end of the piston 16 being in contact with any surrounding structure in the drop open position, the piston 16 can be made shorter in length than the piston 116 of the conventional drilling tool 110 of a comparable overall outer diameter. FIG. 13A is an enlarged section view of a portion of the conventional drilling tool 110 shown in FIG. 10A , where the piston 116 is in its uppermost position and just prior to commencing a downward stroke. As shown in FIG. 13A , the intake flow follows the same flow path 180 that includes the two sharp bends 186 , 188 as shown and as described above in connection with FIG. 11A . In addition, as the intake flow travels through the aperture 194 and then flows in a downward direction along the lower segment 190 within the inner passageway 196 , it encounters a volume of pressurized air in an area 121 ( FIG. 10A ) surrounding the piston 116 . At the position shown in FIG. 13A , the piston 116 has just moved upward (i.e., from the position shown in FIG. 11A ) such that its upper end is no longer sealed against the inner cylinder 113 , thereby creating an upper opening 119 (i.e., the space between the outer surface of the piston and the inner relieved surface of the inner cylinder 113 , which has a larger diameter) in the passageway 196 . The opening 119 thus connects the lower portion of the passageway 196 with the space above the upper surface of the piston 116 , which is at a lower pressure. Once the opening 119 is established, the higher pressure fluid in the area 121 seeks to expand, thus exerting an upward pressure in the direction of the opening 119 . At the same time, however, a portion of the intake flow from the aperture 194 is seeking to flow downwardly through the passageway 196 (a portion of the intake flow also flows upwardly as shown). Thus, the intake flow, particularly along the lower segment 190 , must overcome the oppositely directed pressure 210 from the area 121 . As shown by the arrows, this confrontation takes place in a highly constricted area. Because of this confrontation, the intake flow along the intake flow path 180 experiences greater energy losses and its resulting velocity is lower. FIG. 13B is an enlarged section view of a portion of the drilling tool 10 according to this application, taken from FIG. 10A . In contrast to the conventional drilling tool 110 , the intake flow path 92 and the filling flow path 200 are arranged for increased efficiency. First, the number of sharp bends in the intake flow path is reduced (in the case of the flow path 92 , there are no sharp bends). Second, the intake flow path 92 and the filling flow path 200 are configured so that they are spaced apart from each other rather than directed along nearly the same axis. Third, the area where the intake flow and the filling flow first encounter each other (i.e., where they are first no longer separated from each other by a wall), has a much larger cross section to promote separation between the flows. Comparing FIG. 13B to FIG. 13A , it can be seen that the cross-sectional area of the inner passage way 96 in the area where the flows 92 and 200 pass each other is much greater than the area of the inner passageway 196 adjacent the aperture 194 . In addition, as described above, there only four such flow path areas as shown in FIG. 13A , whereas there are a much greater number of the flow paths shown in FIG. 13B . Therefore, compared to the conventional drilling tool, the flow 92 in the drilling tool 10 flows with much less energy loss due to conflict with the flow 200 , and vice versa. In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting in scope. Rather, the scope is defined by the following claims.	A portion of a drill assembly operated by a supply of compressed fluid comprises a backhead, a cylinder portion, a hollow elongate wear sleeve and a piston. The backhead has a proximal end connectable to the supply, an axial bore and an open distal end having an integrated cylinder portion defined therein. The backhead has passages extending between the axial bore and the outer surface of the backhead. The cylinder portion is aligned with and in selective fluid communication with the backhead. The hollow elongate wear sleeve surrounds the cylinder portion and is connected to the backhead. The piston is housed by the wear sleeve and has a proximal end shaped to fit within the cylinder portion. The piston is slideably movable along the wear sleeve and the cylinder portion in response to compressed fluid conveyed through the backhead. When the drill assembly is in a drop open position, the proximal end of the piston is radially spaced apart from a nearest surrounding surface.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATIONS Applicant claims priority under 35 U.S.C. §119 of Spanish Application No. P 2003 01681 filed Jul. 11, 2003. Applicants also claims priority under 35 U.S.C. §365 of PCT/ES2004/000306 filed Jun. 30, 2004. The international application under PCT article 21(2) was not published in English. OBJECT OF THE INVENTION The present invention relates to a barbed-type mesh BACKGROUND OF THE INVENTION In areas of forest pasture, livestock and game frequently eat the leaves and shoots of young trees up to a height of around two meters, often preventing the regeneration of the trees. To prevent this, the landowners often erect cages around the young trees that usually comprise a covering structure, using all types of materials; works meshes, electrowelded mesh, grills, wooden stakes and boards, normal metallic material, semirigid metallic livestock material, chicken wire, etc., with the structure formed from corrugated iron bars, PNL stakes or wooden stakes. Once the cage has been constructed, it has to be covered with barbed wire to prevent the livestock or game from scratching at the cage eventually pushing it over. This makes the operation more expensive, as it requires more material and more manpower to set it up, making it almost impossible to reuse this cage with another tree as it is difficult and costly to disassemble it. Therefore, although in practice, several types of protector are used, all are homemade and there is currently no specific product for this end. This problem could be minimized if there a rigid or semirigid material existed that was barbed and that could serve to cover a structure of stakes and crossbars. A wide range of metallic or meshes plastic meshes and bars and metallic nets are available on the market, obtained from electrolytic processes or other processes, of the “flat” type that can be used for the ends described, but none of them are of the barbed types (sclerophyllic), all of them being smooth, and so they do not perform the function for which the sclerophyllic mesh is designed. The only barbed mesh that exists is military, made from braided barbed wire, but it is not flat, occupies a large volume and is not indicated for the ends of sclerophyllic mesh. There are also models of forest protectors for smaller game and/or roe deer, although these are ineffective against livestock or larger game, as they are not barbed. DESCRIPTION OF THE INVENTION The use of “sclerophyllic mesh” has the advantages of normal metallic material, of the rigid and semirigid type, which having a certain hole size prevents the livestock from putting their head through and eating the tree, and those of barbed wire, that, on being barbed, prevent the livestock from rubbing against them and knocking over the cage or breaking it. In accordance with the invention, the sclerophyllic mesh is an electrowelded mesh, consisting of wire or metal bars, which can be of any thickness or diameter, with any type of cross-section, whether circular, square, rectangular, pentagonal or any other. The mesh can be formed by materials of different thicknesses and these can be distributed in any form in the sheets in which the mesh is made. This mesh can present polygons of any form, and the holes can be of any size, and can be formed a polygons of one or several shapes and sizes. The distribution of the squares in the mesh can be of any type. This mesh will have some sharp points or points on its surface, or surfaces, such that it is sclerophyllic, where the sharp points can be of the same material as the mesh or of any other, and can be joined to the mesh by electrowelding, braiding, or any other system, and can be placed in any way, either at the vertices of the mesh, or at any other point, and they can be arranged in several forms, having any density and distribution, homogeneous or not. The arrangement of the sharp points will be facing one side or both, and the sharp points can have any type of section or any length. The orientation of the sharp points with respect to the mesh can be perpendicular, oblique, or any other. The sharp points can be straight or curved, individual or multiple, single or braided, or of any other type. The manufacturing process of the mesh will be by electrowelding, such that a flat, rigid or semirigid mesh is obtained that is barbed. The mesh will be produced in sheets of any size. The sheets can have any distribution of squares of the mesh with respect to its edges, which can have any type of finish. The sclerophyllic mesh allows any type of prism. In this fashion, the sclerophyllic mesh offers the advantages of normal metallic material of the rigid or semirigid type, which because it has a certain hole size prevents the livestock from sticking their heads through and eating the tree, and the barbed wire, which because it is barbed, prevents the livestock from rubbing against it and knocking over the cage or breaking it. Although the main use foreseen for the mesh is the one presented above, other possible uses are not discarded, such as pastoral farming, industrial or urban uses. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a view of an example of an embodiment of the esclerofila mesh of the invention. DESCRIPTION OF A PRACTICAL EMBODIMENT OF THE INVENTION The sclerophyllic mesh 1 of the invention is comprised of a flat mesh 2 formed from polygons 3 of any shape or size, made by electrowelding from metallic material 4 . At the nodes of the mesh, in this example of an embodiment, sharp points 5 are attached by any means that can be of any length and any type of material, which can present any distribution, density, and arrangement with respect to the plane of the mesh. With the nature of the invention sufficiently described, as well as a practical embodiment thereof, it should be stated that the details of the arrangements indicated previously and represented in the attached drawings can be modified without altering the basic principle.	A barbed-type mesh is primarily intended to be used to protect young trees from livestock or other animals. The mesh is made from wires or electrowelded bars having sharp points on the surface thereof. The sharp points are electrowelded at intersections of the mesh.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION The present invention relates to loader boom assemblies for self-propelled loaders which are controlled to maintain the forward ends of the boom assembly in a generally vertically linear path throughout a substantial portion of the upward travel of the boom assembly. Loader boom assemblies which provide a generally vertical movement of a bucket used for lifting material have been used. For example U.S. Pat. No. 4,355,946 illustrates a lift arm control linkage structure for a loader which uses a long lift arm support link at the rear portions of the loader boom assembly, to provide an altered upward path of a front bucket, and at the same time provides bucket leveling. U.S. Pat. No. 3,215,292 issued to Halls on Nov. 2, 1965 illustrates guide links which operate to cause lift arms of a loader to extend out at the same time they are raised. However, in this unit the bucket continually moves outward from the supporting machine as the bucket raises, rather than moving on a generally vertical path in the upper portions of the range of movement. SUMMARY OF THE INVENTION The present invention relates to a boom assembly for a loader which comprises a pair of lift arms, each including a pair of articulated links which are controlled in movement as the lift arms are raised to cause the outer ends of the lift arms to move generally vertically and substantially linearly when the lift arms are raised beyond a horizontal position. The articulated links of each lift arm include a main forwardly extending lift arm link or section and a rear, substantially shorter lift arm link or section which has one end pivoted to the main lift arm link or section and the other end pivoted to the self propelled loader frame. The path of movement of the main lift arm sections is partially controlled by a control link that is connected to the self propelled loader frame at a forward end of the frame and to the lift arm main section of the respective lift arm. The lift arms are raised by operating hydraulic cylinders or actuators which react forces between the main lift arm sections and the loader main frame. As the boom assembly is raised the rear lift arm link first is controlled to pivot about its pivot at the main loader frame so as to move the other or first end of the rear link which is pivoted to the main lift arm link rearwardly under control of the control link. After the bucket at the forward end of the boom assembly is about level with the pivot of the rear lift arm link to the loader main frame the one end of the rear lift arm section or link starts to move forwardly as the boom assembly is raised further, and the main lift arm sections also move forwardly so that the rear and main lift arm links or sections unfold as the boom assembly is raised, to keep the forward ends of the lift arms and bucket moving in a generally vertical path throughout the range of higher movements of the lift arms forming the boom assembly. This positions the bucket support at the front ends of the lift arms for easier dumping of material into a truck, for example, and has the advantage of not having the forward ends of the lift arms move rearwardly in an arc during the upper portions of lift movement of the lift arms. Both sections of each loader lift arm, the hydraulic actuator and the control link for the respective lift arm, are made to be in a common plane so that the lateral dimensions of the operators compartment do not have to be changed from existing dimensions of skid steer loaders with conventional booms. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side elevational view of a skid steer loader having a loader boom assembly made according to the present invention installed thereon with parts broken away; FIG. 2 is a side elevational view of the loader of FIG. 1, taken from the opposite side; FIG. 3 is a part-schematic side elevational view, showing a bucket and boom assembly in a plurality of raised positions to illustrate the path of movement of the outer ends of the boom assembly and a supported bucket; and FIG. 4 is a schematic perspective view of the loader boom assembly shown in FIG. 1 with the skid steer loader plain frame also shown, but with other parts removed for sake of clarity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A loader assembly indicated generally at 10, made according to the present invention, is mounted onto a skid steer machine or prime mover 12 that hasa main frame 14 that extends longitudinally in fore and aft direction, and is supported suitably on front and rear wheels 16. Wheels 16 are driven ina suitable manner through a drive train supported on the main frame 14, from an engine (not shown) in an engine compartment 15 mounted directly behind an operator's compartment indicated schematically at 18. Frame uprights 20 at the rear portion of the main frame are used for supporting the loader 10. Each of the uprights 20 comprises a part of spaced apart plates. It is known that when conventional loader booms, mounted at a single pivot axis to the loader frame are raised and lowered, the outer forward ends travel in an arc, and when the boom starts to raise, there is some forwardmovement of a supported bucket and, after the pivoting boom goes over center, there is a substantial amount of rearward movement of the bucket, as well as upward movement, which tends to shorten the forward "reach" of a bucket with the boom assembly in a raised position. The main frame 14, frame uprights 20, the drive wheel configuration, fenders 22, and wide operator's compartment 18 are all features of the standard skid steer loaders. The operator's compartment extends laterally across the entire main frame. The operator's compartment extends substantially the full width between the inner plates of frame uprights 20and fenders 22 (see FIG. 4). The present articulated boom is designed to fit onto the basic construction of the main frame, uprights and wide cab while permitting the usual access to service the machine in the same manner. An engine compartment 15 is immediately behind the compartment 18 and the engine access door or panel 15A can be opened in the same manner as on existing machines because of the lack of interference from the rear links 32 and clearance of cross member 36 due to use of high pivots 40. The high rear pivot of existing machines is maintained, in order to accomplish the purposes of using the basic loader design of conventional radius arc booms. Skid steer loaders of the general type shown herein are well known and are manufactured by the Melroe Company, a business unit of Clark Equipment Company of Fargo, N.D., and are marketed under the registered trademark BOBCAT. The loader 10 includes a lift boom assembly 24, which is, in the preferred embodiment, a two section boom. The two section boom includes a main lift arm assembly 26 and a rear lift arm link assembly 28, which are pivotally mounted together. The main lift arm assembly 26 includes a pair of laterally spaced main lift arm, links or sections 30, and a pair of rear or second lift arm links or sections 32. The main lift arm links 30 are onopposite sides of the main frame connected with suitable cross members at the forward ends thereof, for example with a cross member shown at 34, andthe spaced rear lift arm links 32 on opposite sides of the main frame are connected together with a suitable cross member 36. The main lift arm assembly 26 has forward and rear ends, and at its rear end the main lift arm sections are each pivotally connected with suitable pivot pins 38, forming a pivot axis, to first ends of the rear lift arm links 32. The connection is made so the main lift arm sections 30 and the rear lift arm links 32 lie on a common plane along the side of the operators compartment. In addition, each of the rear lift arm links 32 is pivotally connected on suitable pins 40 forming a pivot axis to the respective frame uprights 20,adjacent the rear portions of the main frame 14, and at the upper portions of the upright and between the plates forming the respective frame uprights 20. The axis of the pins 40, which define the pivoting axis of the rear lift arm link assembly is raised a substantial distance above a supporting surface indicated generally at 42. The main lift arm sections 30 include downwardly extending forward arms 44 thereon, which extend downwardly and forwardly, just ahead of the forward wheels 16, with the lift boom assembly 24 in a lowered position. At the forward ends of the main lift arm sections 30 there is an attachment pin 46 which defines a pivot axis for supporting a working implement. As shown, the working implement is a bucket 48 that is supported on a subframe 50. The subframe in turn is pivotally mounted on the pins 46, and is controlled by a tilt cylinder or actuator illustrated schematically at 52, in a conventional manner. The tilt cylinder 52 is connected at its based end to a support 53which is mounted on cross member 44. The subframe 50 is an attachment framethat is sold by Melroe Company, a business unit of Clark Equipment Company,located at Fargo, N.D., under the trademark BOB-TACH. Of course, any desired mounting for the implement or bucket 48 can be utilized, and in most instances there is a defined point such as the axis of pin 46 or the front lip of the bucket 48 that can be used for determining the path of movement of the forward ends of the main lift arms 30 during raising and lowering motion. In this form of the invention, the main lift arm sections or links 30, havecontrol arms 54 fixed thereto, at a location spaced forwardly from the pivot pin 38. The control arms 54 are made of two spaced plates and extenddownwardly along the sides of the operator's compartment 18, as can be seen, to a location just above the fenders 22. Hydraulic actuator or cylinder attachment plate sections 56 are secured to the main lift arm section 30 on each side of the boom assembly in a suitable manner, or can be part of the plates forming control arms 54. A separate double acting hydraulic actuator or cylinder assembly 58 is mounted on each of the sides of the main frame, and has a rod that is extendable and retractable. The rod has a rod end that is connected with asuitable pin 60 between the respective spaced plates 56. The base end of each actuator or cylinder 58 is connected with a suitable pin 62 to the main frame 14 and, as shown, is located between the plates forming uprights 20. It should be noted that the base end pin 62 for the double acting hydraulic actuator or cylinder 58 is substantially lower than the pivot pins 40. The actuator extends upwardly and forwardly from the pivot pin 62 to pin 60. A control link, which in the form of the invention is a fixed length or rigid link, is indicated generally at 66. There is a rigid control link oneach side of the main frame 14, and thus there is a separate control link 66 for each of the lift arm of the boom assembly. Each of the links 66 hasa forward end pivotally mounted with a suitable pin 68 to a bracket fixed on the respective fender 22 and thus to main frame 14 of machine 12. The opposite end of the rigid link 66 is connected with a suitable pin 70 to an end of the respective control arm 54 on each of the main lift arm sections 30 and is positioned between the plates forming the respective control arm 54. Each link 66 is substantially horizontal with the boom assembly 24 in its lowered position. When working with a bucket and the like, there is a rearward force on the boom assembly during the loading of the bucket. The horizontal links 66 are substantially parallel to the direction of rearward force and will tend to hold each of the individual main lift arm sections 30 and rear lift arm links 32 from rearward movement. Part of this rearward load of course will also be transferred through the pins 38 to the rear lift arm links 32 and thus to the pivot 40 on the frame uprights, but with the articulated lift arms, that is, two lift arm sections pivoted together, there would be a tendency to cause folding of the main lift arm sections and rear lift arm links from horizontal load vectors acting rearwardly against the pin 46. The links 66, actuator 58, the main lift arm section 30, and the rear lift arm section or link on each side of the boom assembly lie in a common plane to save lateral spaceand to fit existing skid steer machines without reducing the width of the operator's compartment or increase the overall width of the machine. The actuators or cylinder assemblies 58 can be operated using a valve and asource of hydraulic pressure (not shown) to raise the boom assembly 24 to araised, dumping position. As the boom assembly raises, the path of travel of the axis of the pin 46, or front edge of the bucket will define a substantially vertical path throughout the upper part of the working rangeused for dumping of buckets. Referring to FIG. 1, the boom assembly 24 is shown at its lowered position. In FIG. 3, the path of movement of the pin 46 is illustrated, and after the pin 46 reaches a height above the supportsurface 42 substantially equal to the level of the pin 40 (as shown by a horizontal dashed line in FIG. 3), instead of moving on an arc rearwardly at the same time that the lift arms are raised further, the axis of the pin 46 moves substantially vertically to the full raised position of the lift arms. The tilt cylinder 52 can be operated as desired for tilting thesubframe 50 and the bucket 48 about the axis of pins 46, in the usual manner. It also follows that in any particular tilted position of the bucket 48, each point of the bucket, such as the leading edge, will move along a path corresponding to the path of the axis of the pin 46. In the lowered position of the boom assembly 24, the main lift arm section or link 30 and the rear lift arm section or link 32 on each side of the loader form an included acute angle between the center line of the rear link 32, between the axes of pivot pins 38 and 40, and the line between the axes of pivot pin 38 and pin 46. This included angle is represented bythe double arrow 74. As the lift cylinder or actuator 58 is operated to start to raise the boom assembly 24 and, therefore, the bucket 48, the included angle represented at 74 will first decrease as the rear lift arm links 32 will be forced to move rearwardly by the rigid link 66, which pivots about pin 68 in an upward arc. The control arm 54 positions the pivot pin 70 for the rear end of link 66 in a location such that rearward movement of the lift arm link 32 occurs as the arms swing. Pin 46 then moves upwardly along a path 47 that is shown in FIG. 3, and when the cylinder or actuator 58 has been extended toa point where the boom assembly 24 is about one-third of its total upward travel the included angle indicated by arrow 74 stops decreasing, and thenstarts increasing again as the two lift arm sections, comprising the main lift arm section or link 30 and the rear lift arm section or link 32 startto unfold as the end of link 66 moves forward on an arc. The effective length of the boom assembly 24 from pivot pin 40 to the front end increases during the upper two-thirds of its upward travel to cause the vertical path of movement of the pin 46 and associated parts of the bucket. The rigid control link 66 thus controls the path of pivotal movement of the pivot pin 38 as lift arm link 32 pivots about the pin 40. By proper selection of the link geometry, including the length of the link66 to be of a substantial length, and approximately twice the length of therear lift arm link 32, and keeping rear lift arm link 32 much shorter than lift arm link or section 30, the desired path of travel of the pin 46 and bucket 48 can be achieved. The same path of travel is followed when the lift arms are lowered, becausethe control link 66 is fixed in length. The present boom assembly achieves the objective of having a longer reach in the upper portions of the path of movement of the boom assembly so that it is easier to dump a bucket into a truck, and also that it is easier to make a pile that is higher, while maintaining the advantages of having a high pivot boom point 40 thatis present in existing skid steer loaders, improved lifting capacity, and still having a compact loader which is as maneuverable as the prior skid steer loaders. The plane defined by the axes of pins 68 and 70 is above the axes of the pin 62 for the lift cylinders or actuators 58, and the pin 70 is rearwardly of the pin 68 so that from the generally horizontal position oflink 66 with the boom lowered, the pin 70 will move upwardly and forwardly which will cause the rear link 32 to first move rearwardly. The axis of pin 70 crosses a plane defined by the axis of pins 68 and 38 and goes "overcenter" as it raises. At a selected raised position of the main lift arm sections, the rigid link 66 will cause the rear or second lift arm links to start to move forwardly as the main lift arm sections are furtherraised, again causing the included angle indicated by arrow 74 to start to increase. The effective length of the boom assembly comprising the main lift arm sections or links 30 and the rear lift arm links 32 increases as raising continues. It should be noted that the link 66 could be made adjustable in length to suit individual conditions that are desired for the path of movement, and provide for different control paths of the pin 46. However, the mechanicallinkage illustrated herein provides the desirable vertical path of movementof the pin 46 when the bucket has been raised to a desired level. In other words, the bucket raised along a substantially vertical path after it has reached a desired level near the level of the pivot axis of pin 40. The loader assembly with the short rear lift arm links, that are mounted ona high pivot improves the rigidity of the lift boom assembly 24 so the liftarms travel in a definite path with clearance maintained along the sides ofthe operator's compartment. The rear lift arm links 32, mounted on the highpivot 40 to the frame uprights 20, provides a boom assembly having the benefits of an articulated boom without extending into the space needed for the rear engine compartment opening, so that there is good service access for the engine compartment. It does not extend rearwardly beyond the rear access door 15A of the engine compartment 15. The articulated boom loader of the present invention has a large degree of commonality of basic frame and drive structure with conventional skid steer loaders. The path of movement of the bucket 48, and the forward ends of the lift arms, as stated, is such that the rear lift arm links 32 move rearwardly upon initial lifting, as guided by the rigid links 66. This tends to move the bucket in a more vertical path initially, so that the bucket 48 and its load stay close to the front tires and front of the main frame 14 as the bucket is first lifted, rather than moving out on a radius. Thus, the rearward movement of the rear lift arm links has important features in defining the initial lifting path of the bucket. CONCLUSION The present invention provides a vertical lift path in the range of movement of a loader boom where the reach of the boom normally is reduced.This permits the operation of the loader in filling trucks and piling material to proceed more easily. The control linkage provides a positive and reliable control for obtaining the vertical path of movement. The present invention provides a vertical lift path in the range of movement of a radial arc boom machine where the reach of the boom normallyincreases or moves forwardly. This mechanical linkage system of providing both inward movement initially and increased reach near full lift height can be packaged on a conventional skid steer machine design. This maintains the existing features of machine design, production processes, and field service procedures in the areas of operator compartment, controls, engine, transmission, hydraulics and hydrostatics, cooling system, electrical system, service access features and means of connecting attachment tools to the skid steer machine. Although the present invention has been described with reference to the preferred embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.	A loader boom assembly has articulated lift arms that have first and second lift arm sections pivotally mounted together. The rear lift arm section is pivotally mounted to rear portions of a prime mover frame. The main lift arm section is substantially longer than the first lift arm section and pivots on the outer end of the rear lift arm link. The lift arm sections are in a folded position when the lift arms are lowered, and a control link is provided to cause the lift arms to unfold as the lift arms are raised to keep the forward portion of the main lift arm section moving along a generally vertical path after a selected lift height to provide a better forward reach of the boom assembly at the higher range of lift. The proportional lengths of the lift arm sections and the control link and the placement of the pivot points and actuators on the main frame also provide structural integrity and efficient power utilization.
You are an expert at summarizing long articles. Proceed to summarize the following text: RELATED APPLICATION [0001] This application relates to and claims the benefit of priority of prior copending U.S. Provisional Application No. 60/420,807, filed Oct. 23, 2002, said Provisional Application being hereby incorporated by reference into the present specification. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to a concrete forming panel which includes a forming face which has a reinforcement on the rear side of the forming face adapted for gripping elements removably attached thereto. The reinforcement is configured to resist expansion of openings through the forming face. More particularly, it is concerned with a concrete form and method of its use in connection with the pouring of low concrete walls or pads where the form may be held in place by stakes driven into the ground. [0004] 2. Description of the Prior Art [0005] The formation of concrete walls and pads is well known and often involves the use of wooden or metal forms. Metal forms are more expensive, but also more durable and may be repeatedly used. When concrete pads are to be poured in residential construction, there is a need for concrete forms which can be quickly and economically set up and dismantled for use at the next site. Examples of known forming panels include those shown in U.S. Pat. Nos. 4,708,315, 4,958,800, 5,058,855, 5,184,439 and 5,965,053, the disclosures of which are incorporated by reference herein. [0006] One problem especially presented by the use of metal forms for pouring foundations such as concrete pads involves their use on rough ground. The metal forms have a permanent shape, and there is a desire to avoid permanently altering or damaging the forms by drilling openings to receive tie rods, bars or tensioning cables therethrough, or driving nails through the frame or face plate of the form to indicate level lines so that the concrete can be poured to a desired depth with a level, horizontal surface. Also, rocks, stumps or other solid objects maybe buried just below grade, and stakes conventionally used for anchoring the forms may encounter such objects. are particularly presented in using concrete forms for form. [0007] In addition, it is known to post-tension concrete slabs by the use of such tensioning cables. Post-tensioning concrete slabs uses tensioning cables surrounded by sheaths which are positioned in the pouring area and after the poured concrete is hardened, stretching the cable by applying tensioning at the ends through the use of a stressing jack and then anchoring the cable ends in the concrete. Such a practice improves the response of the resulting concrete slab to loading, and reduces deflections and cracking. Further, the use of post-tensioning in concrete slabs may result in slabs which are generally thinner, relatively longer, and reducing the weight of the resulting poured structure. However, in order to initially position the live end anchor which is typically received within a cone to create a pocket for access after concrete hardening and the dead end anchor which is encased within the hardened concrete, it has been heretofore largely necessary as a practical matter to employ wooden forms which must be discarded after use. [0008] There is thus a need for an improved concrete forming panel and method of use which overcomes these problems. SUMMARY OF THE INVENTION [0009] These and other needs are largely met by the concrete forming panel of the present invention. That is to say, the concrete forming panel hereof is particularly useful in forming foundations such as concrete pads where it is desirable to anchor the forming panel to the ground by stakes, and wherein the forming panel may need to be penetrated through the front side of the face plate. To this end, the concrete forming panel hereof includes at least one and preferably a plurality of sets of reinforcing ribs on the back side of the face plate which are configured and position for gripping a variety of elements passing through the face plate, either themselves or with the use of wedges depending on the orientation of the element relative to the front side of the face plate. [0010] Broadly speaking, the concrete forming panel of the present invention includes a face plate having a frame, a front side and a rear side, and at least one set of reinforcing ribs received on the back side, the ribs being positioned closely adjacent one another and parallel for gripping objects placed therebetween. The face plate may be formed with a face panel having the front side and rear side which is separate from the frame, or a portion of the frame may be cast by extruding or the like or forged so that the face panel is integral with some of the rails and the reinforcing ribs. The elongated reinforcing ribs preferably extend longitudinally along the back side of the face plate, but alternatively or in addition may extend along the frame. The face plate and the ribs are preferably provided of aluminum, which as used herein includes both elemental aluminum and alloys wherein the primary constituent is aluminum. Because aluminum is relatively soft and subject to wear, the ribs may include longitudinally extending slots which receive therein reinforcing elements of a harder material, such as steel. Most preferably, the reinforcing elements are shiftably received in the slots, thereby permitting the reinforcing elements to be moved along the slots to vary the locations where wear occurs and also permitting the reinforcing elements to be located to engage an element to be gripped. [0011] The face plate is preferably provided with opposing top and bottom rails, and at least one set of holes in the frame on each of the top and bottom rails. A stake may be placed through one of the holes of each set, so that the stake penetrates the ground and holds the forming panel in place. The stake may be positioned perpendicular or skew to the rails to avoid rocks or other impediments to penetration into the soil. The ribs may themselves engage the stake, or more preferably a wedge may be placed between the ribs and engage the stake to secure it and therefore the form in the desired placement. The wedge may be driven into engagement with the stake by a hammer or the like, whereby the face plate is firmly held in place. Two or more stakes may be used to resist movement of the forming panel. [0012] It may also be desirable to provide openings in through the face side of the face plate for the passage of tie rods, anchoring cables or the like. After their use, the openings would permit leakage of concrete therethrough. However, the forming panel of the present invention permits these holes to be plugged through the use of elements such as plugs or the like which may be gripped by the ribs. This not only permits the forming panel to be reused, but permits removal of the elements as desired when it is again necessary to use the opening. [0013] Further, it may be desirable to penetrate the face plate during its use. Because the face plate is preferably provided of aluminum, a nail or other fastener may be driven through the face plate so that it passes between the ribs. The nail may be used to connect the forming panel to lumber on a face of the forming panel or to wood forming panels, reinforcements or stakes. This may be especially advantageous where tensioning cables are used to hold spaced-apart and opposed panels in position during the pouring and curing of the concrete, and there is a need to attach the cable to the panel. [0014] These and other advantages will be readily apparent to those skilled in the art with reference to the drawings and the description of the preferred embodiment which follows. BRIEF DESCRIPTION OF THE DRAWINGS [0015] [0015]FIG. 1 is a rear perspective view of a concrete forming panel in accordance with the present invention, showing the reinforcing ribs along the back side of the face plate, the concrete forming panel being anchored to the ground by stakes and connected to and opposing other forming panels by live end and dead end anchors and tensioning cables passing through a pouring area between the forming panels for receiving flowable concrete for curing and hardening; [0016] [0016]FIG. 2 is a rear elevational view thereof, showing one of the stakes perpendicular to the upper rail and another stake skew thereto, and showing in dashed lines the position of a stake when held by a hanger on the forming panel; [0017] [0017]FIG. 3 is an enlarged, fragmentary horizontal cross-sectional view taken along line 3 - 3 of FIG. 2, showing the receipt of a plug element in an opening extending through the face panel of the face plate, a reinforcing rod received in a slot in the reinforcing ribs, and a wedge gripped between the ribs; [0018] [0018]FIG. 4 is an enlarged, fragmentary vertical cross-sectional view taken along line 4 - 4 of FIG. 3, showing a nail fastener penetrating through the front side of the face plate and gripped between one of the pairs of reinforcing ribs for attachment of wood blocks or the like to the panel; and [0019] [0019]FIG. 5 is an enlarged, fragmentary vertical cross-sectional view taken along line 5 - 5 of FIG. 2, showing the plug element gripped by a pair of ribs and a hanger for retaining the stake prior to use, the hanger including an elastomeric grommet. DESCRIPTION OF THE PREFERRED EMBODIMENT [0020] Referring now to the drawings, a forming panel 10 for use in forming structures from flowable cementatious material such as concrete broadly includes a face plate 12 and at least one, and preferably a plurality of pairs of, reinforcing ribs 14 . A hanger 16 may be provided for holding a steel stake 18 used with the forming panel 10 . A fastening element 20 may be used with the forming panel 10 , and one or a plurality of plug elements 22 may be used to close openings in the face plate 12 . As shown in FIG. 2, the forming panel 10 is particularly useful for forming foundations such as concrete pads which rest directly on the ground 24 . [0021] In greater detail, the face plate 12 is preferably fabricated of an aluminum alloy such as ASTM 6061 T-6, and includes a frame 26 and a face panel 28 having a front side 30 and a back side 32 . The frame 26 preferably includes a top rail 34 and a bottom rail 36 , and first and second side rails 38 and 40 which together with the back side 32 of the face panel 28 define a rear area 41 inwardly of the margins of the rails. The face panel 28 may be formed separately and welded to the frame 26 , or alternatively as shown in the drawings, the face panel 28 and top and bottom rails may be integrally formed by casting, such as extrusion, and the side rails 38 and 40 then welded to the extrusion. The frame 26 including the rails is fabricated of a greater thickness of material along at least some parts thereof than the face panel 28 . [0022] The top rail 34 and the bottom rail each include at least one, and preferably a plurality of sets 42 of holes 44 therethrough. As used herein, a set 42 of holes 44 is meant to mean a plurality of holes 44 more closely spaced together than the distance between holes 44 of different sets 42 . As shown in FIG. 1, the top rail 34 thus includes four sets 42 A, 42 B, 42 C and 42 D of three holes 44 each, and the bottom rail 36 includes four sets 42 E, 42 F, 42 G and 42 H of three holes 44 each, the set 42 A being positioned in registry above and opposite the set 42 E, and the same respective relationship existing between set 42 B and 42 F, set 42 C and 42 D, and set 42 D and 42 G. [0023] In addition, the side rails 38 and 40 are each provided with a plurality of holes 44 for receiving therethrough couplers, such as pins 46 and their associated wedges for coupling the forming panel 10 to similar or compatible adjacent forming panels as shown in FIGS. 1 and 2. Furthermore, the side rails 38 and 40 may include recesses 48 on their outer surface which, in some applications, may facilitate the receipt of tie bars or the like which may be secured by pins 46 for connecting the forming panel 10 to an opposite forming panel 10 A or to an adjacent forming panel. A pouring area 50 into which flowable concrete maybe poured is located between opposed forming panels 10 and 10 A for forming the structure between front sides of the opposing face panels. The face panel 28 may be smooth or textured on its front side 30 , texturing being provided to form a pattern to be imparted to the concrete hardening thereagainst, such as a brick pattern. [0024] The pairs of reinforcing ribs 14 preferably extend longitudinally across the back side 32 and may either extend the width of the form between the side rails 38 and 40 as shown with respect to the pair of reinforcing ribs 14 C, or may be interrupted by openings 52 in the face panel 28 as shown by pairs of reinforcing ribs 14 A and 14 B as described below. Each pair of ribs 14 includes an elongated first rib 54 and an elongated second rib 56 which are preferably mirror images and cantilevered from the back side 32 of the face panel 28 . The ribs 54 and 56 may be cast by extrusion or the like as a part of the face plate 12 as shown in FIGS. 4 and 5, or may formed separately and secured by welding, brazing or the like to the face panel 28 . [0025] Each of the ribs 54 and 56 preferably includes a longitudinally extending slot 58 which faces the opposite rib and the gap 60 therebetween, so that the slot 58 communicates with the gap 60 . The gap 60 is preferably less than about 25 centimeters across between the ribs in order that the ribs 54 and 56 of each pair 14 may grip elements received therebetween. One or a plurality of reinforcing elements 62 are preferably of a shorter length than the ribs and thus slidably received in the slot 58 which permits the reinforcing elements 62 to be shifted longitudinally along the slot. [0026] The reinforcing elements 62 are preferably steel rods 64 . Aluminum has a much lower hardness than steel (about 30 on the Brinnell hardness scale (Bhn) for cold rolled ASTM 6061 aluminum versus a Bhn number of about 111 for hot rolled SAE 1020 steel and a Bhn of 179 for hardened, tempered SAE 1020 steel). Thus, the use of the steel reinforcing element 62 greatly reduces wear on the ribs. The use of steel for the reinforcing element 62 also provides increased strength to the rib 54 or 56 to which it is attached. For example, ASTM 6061 aluminum has a tensile strength of about 20,000 to 40,000 psi and a yield strength of about 8,000 psi, whereas hot rolled SAE 1020 steel has a tensile strength of about 55,000 psi and a yield strength of about 30,000 psi and hardened, tempered SAE 1020 steel has a tensile strength of about 90,000 psi and a yield strength of about 60,000 psi. A particularly preferred steel for use as the wear element is an ASTM-228-93 steel wire having a tensile strength of about 254,000 psi to about 259,000 psi and a Bhn of about 518 to 529. [0027] The hanger 16 is provided for retaining the stake 18 in place on the form when form 10 is not in use. The hanger 16 is typically provided of two aluminum brackets 64 and 66 longitudinally spaced along the back side 32 and secured thereto by welding, brazing, rivets or the like, each having a passage 68 of sufficient size to receive the stake 18 therethrough as shown in FIGS. 1 and 2. At least one of the brackets 64 , 66 includes an elastomeric grommet 70 of synthetic resin or rubber to grip and hold the stake. [0028] As shown in FIGS. 3, 4 and 5 , the pairs of reinforcing ribs 14 are configured to grip elements received in the rear area 41 . Openings 52 may be provided in the forming panel 10 , preferably along the longitudinal length of the pairs of reinforcing ribs 14 , to permit the use of tie rods or cables which must pass through the face plate 12 . When it is desired to block or close an opening 52 in the face plate 12 which extends from the front side 30 through to the rear side 32 , a plug element 22 may be held by the opposing ribs 54 and 56 . The plug 22 preferably is provided of aluminum or other durable material, but may also be provided of synthetic resin or rubber and includes a central, substantially cylindrical body 72 and wings 74 extending diametrically opposite therefrom. The body 72 may be placed in the opening 52 with the ribs 54 and 56 holding the wings 74 as shown in FIGS. 1, 2, 3 and 5 . [0029] The pairs of reinforcing ribs 14 are also useful to grip a fastening element 20 , such as a nail 76 driven through the face plate 12 . The nail 76 penetrates the face plate 12 which is typically of aluminum, and then may be gripped between the rods 64 as shown in FIG. 4 to provide steel-to-steel contact and thus avoid wear to the face plate 12 , the cantilevered arrangement of the ribs 54 and 56 permitting them to yield and thus grip the nail. Nails 76 or other fastening elements 20 are useful if a piece of wood 77 needs to be attached to the forming panel 10 , or when an anchor 78 is used when a tensioning cable 79 received in a surrounding sleeve (not shown) is passed through the pouring area and connected to the anchors 78 for anchoring an end of the cable 79 . The head of the nail 76 may be exposed to facilitate removal of a piece of wood or the anchor. The provision of several pairs of reinforcing ribs 14 A, 14 B and 14 C is especially useful for receiving and gripping nails 76 at different heights for different depths of concrete. [0030] In addition, the pairs of reinforcing ribs 14 are particularly useful in connection with fixing the reinforcing panel 10 relative to the stakes 18 . The position of the holes 44 in each set 42 causes the stakes to pass through the rear area 41 . Retaining elements such as wedges 80 of mild steel or other suitably hard material may be provided for receipt in the gap and gripping by the ribs 54 and 56 . The wedges 80 are shown in detail in FIG. 3 and are preferably flat and of a thickness complemental to the gap 60 . [0031] The wedges have a front margin 82 and a back margin 84 which is at an acute angle relative to the front margin. Fingers 86 and 88 are located along the sides of the wedge 80 and extend toward the back margin 84 to aid in placement of the wedge in the gap and permit driving of the wedge 80 longitudinally along the pair of reinforcing ribs 14 which receives it. The depth between the front margin 82 and back margin 84 thus varies as shown in FIG. 3, whereby a stake received in the holes 42 may initially pass by the narrowest part of the wedge 80 , and the wedge then driven longitudinally along the pair of reinforcing ribs 14 receiving it until the back margin 84 engages the stake 18 as shown in FIG. 3. Because the holes 42 have a greater diameter than the diameter of the stakes 18 , the stake may be angled to avoid rocks 90 in the ground as shown in FIG. 2, but the forming panel 10 may nonetheless remain fixed to the stake 18 whether the stake is substantially perpendicular to the top rail or at an acute angle thereto, each of which is shown in FIG. 2. [0032] [0032]FIGS. 6, 7 and 8 illustrate an alternative forming panel 10 B in accordance with the present invention, with like numbers used to indicate features common to forming panels 10 and 10 A, wherein the face plate 12 B includes a frame 26 B having first and second side rails 38 B and 40 B, top rail 34 B and a bottom rail (not shown), and wherein the pairs of reinforcing ribs 14 B are integrally formed with hats 94 . The hats 94 may extend either parallel to the top and bottom rails 34 B and 36 B or extend perpendicular or at other angles relative to the top and bottom rails as shown in FIG. 6. [0033] The frame 26 B may also include reinforcing plates 96 of steel or aluminum alloy which are interior to the rails and serve to reinforce the rails in the vicinity of the holes 44 through the rails. The hats 94 serve to reinforce the face panel 28 B against deflecting loads imparted by the cementations material received thereagainst, and preferably include sloping sidewalls 98 and 100 connected by stretch 102 . The pairs of reinforcing ribs 14 B are preferably integrally formed by extrusion as a part of the hat 94 , and as shown in FIGS. 7 and 8, are positioned adjacent each of the sloping sidewalls 98 and 100 . [0034] The ribs 54 B and 56 B are similar in configuration to ribs 54 and 56 , but include a web 104 connecting the ribs 54 B and 56 B. The web 104 lies against the back side 34 B of the face panel 28 B. The web 104 may be provided with elongated slots 106 at longitudinally spaced intervals therealong to facilitate the passage of fastening elements 20 through the web and the face panel, so that openings 108 created by drilling or driving a nail through the face panel are in registry with the slots 106 . Reinforcing elements 62 B such as rods 64 B are received in slots 58 B in each of the ribs 54 B and 56 B so that the rods 64 B oppose one another to grip elements inserted therebetween as described with regard to the forming panel 10 . [0035] In use, the forming panels 10 , 10 A or 10 B hereof are assembled into forming walls 92 by the use of couplers, and depending on the distance between opposing forming walls, tie bars, tie rods, cables or other connecting structures may be used to hold the forming walls in the desired shape. When cables or tie rods are used which must pass through the forming panel 10 , they pass through the openings 52 in the face plate 12 . Otherwise, plugs 22 are used to close the openings, the plugs being held in place by the clamping action of the ribs 54 and 56 of a pair 14 . [0036] The wedges 80 are placed at desired locations along the length of the pairs of reinforcing ribs 14 proximate to the desired alignment for the corresponding holes 42 of a particular set 40 where the stake 18 is to pass through. The stake 18 is removed from the hanger 16 and driven into the ground, and then the wedge 18 is driven longitudinally along one of the pairs of reinforcing ribs 14 until it engages with the stake 18 . If desired, nails may be driven through the face plate 12 to attach pieces of wood for use as a part of the forming wall or as otherwise needed. Concrete is then poured into the pouring area 50 between the forming walls and against the front side 30 . After curing and hardening of the concrete into the pad or other concrete structure, the stakes are pulled and the forming walls 92 are disassembled for reuse. [0037] As shown in FIG. 1, the forming panel 10 is useful in connection with a post tensioning system, where anchors 78 include both dead end anchor 110 and live end anchor 112 , and a cone 114 is provided between the live end anchor 112 and the forming panel to create a pocket for access. The cable 79 , having a first end 116 connected and fixed to the dead end anchor 110 and a second end 118 which initially passes through the live end anchor 112 , extends through the pouring area between the forming panels 10 and through an opening 52 in the face plate. The anchors 78 maybe held in place by nails driven into the form and gripped by the ribs 14 prior to pouring of the concrete. After the concrete is hardened, the forming panels 10 may be removed, the dead end anchor 110 holding the first end of the cable being encased in the concrete. The cable, permited to shift because it is encased within its sheath, then has its second end 118 connected to a stressing jack to apply a tensioning load on the cable 79 . This tensioning force is transmitted to both of the anchors when the tensioned cable is fixed to the live end anchor 112 . As a result, the tension is then imparted to hardened concrete because the anchors 78 are embedded in the hardened concrete. The cone 114 creating a pocket in the concrete may then be filled and grouted. [0038] Although preferred forms of the invention have been described above, it is to be recognized that such disclosure is by way of illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention. [0039] The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of their invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set out in the following claims.	A concrete forming panel and its method of use is provided wherein the forming panel has a face plate including a frame, a front side and a back side, and one or a plurality of pairs of ribs which extend longitudinally along the back side. The pairs of ribs are provided sufficiently closely together to grip an element passing through the face plate or to grip a wedge which in turn engages the element. The element may be a nail, stake, or other fastener used to hold the forming panel in the ground, to connect the forming panel to other forming panels, or to indicate a desired level for concrete poured against the front side to be cured and hardened into a finished structure, such as a foundation for a building. The ribs may be provided with slots for receiving a reinforcing element of a relatively harder material, and the reinforcing element may be shiftably received in the slot so that its position may be changed as the reinforcing element wears during use.
You are an expert at summarizing long articles. Proceed to summarize the following text: FIELD OF THE INVENTION The invention relates to a five-arm concrete-distribution rig arranged on a vehicle comprising a rig arm 1 hinged to a horizontal pivot joint A on a pivot-bearing block which is arranged on the front axle side of the vehicle and rotatable about a vertical axis. The concrete-distribution rig further comprises rig arms 2, 3, 4 and 5 lying in a travelling position under the rig arm 1 and foldable in pairs at the hinged joints B, C, D and E against the respective preceding rig arm in an alignment essentially parallel to one another. The distribution rig also comprises pipe sections of a feed pipe, wherein the feed pipe can be loaded with concrete and leads to an end hose hinged to the free end of the rig arm 5, and wherein the pipe sections extend along the individual rig arms and are connected with one another at pipe rotating joints, which are axially parallel with respect to the hinged joints. The rig arms 1, 2 and 3 can be folded at their hinged joints B and C in opposite rotational directions so as to be against one another like a Z. The hinged joints B and C have a swivelling range of motion of approximately 180°. BACKGROUND OF THE INVENTION A concrete-distribution rig of this type is known (DE-PS 34 46 290), wherein all rig arms 1, 2, 3, 4 and 5 can be folded against one another at their hinged joints B, C, D and E like a multi-Z-folding. This concrete-distribution rig reaches very far and can be advantageously utilized both in the low-rise building construction and also in the high-rise building construction. The multi-Z-folding further guarantees a quick operational readiness after only a short lifting and partial unfolding of the arm package. The rig also provides a high flexibility, in particular, during the pouring of concrete or the concreting of difficult to access areas whereby dead spaces are essentially avoided during upward feed near the vehicle and also during the pouring of concrete in low spaces. In order to also achieve a mass distribution favorable for the load and moment to be absorbed by the chassis when in the folded travelling position, the hinged joints C and E near the front axle have a swivelling range of 270° between the arms 2 and 3 or 4 and 5, whereas the remaining hinged joints B and D have an angle of traverse of 180°. The pouring of concrete parallel to or along the working plane is possible with the multi-Z-folding. However, to guide the end hose all the way to the cab requires a relatively high unfolding height. Furthermore, in a concrete-distribution rig with four rig arms, it is actually known to fold the rig arms 1, 2 and 3 against one another at their hinged joints B and C in opposite rotational directions like a Z and to fold the rig arm 4 at the joint D in the same rotational direction with the rig arms 2 and 3 against one another. This type of folding has been specially designed for pouring concrete in low spaces because the end hose can be moved over the entire work area from the cab to the maximum extension with a small unfolding height along a predetermined horizontal operating line. However, this four-arm distribution rig cannot be used to provide parallel hose guiding when concrete is supposed to be poured beyond obstacles or from the ground into higher stories. SUMMARY OF THE INVENTION The basic purpose of the invention is therefore to develop a concrete-distribution rig of the above-mentioned type, which can be used both in ground-level low spaces to overcome obstacles and also in higher stories for pouring concrete while guiding a hose parallel with the lowest possible unfolding height. To attain this purpose it is suggested according to the invention that the rig arms 3, 4 and 5 and the associated pipe sections be roll folded, i.e. be folded against one another at their hinged joints D and E each in the same rotational direction with the rig arms 4 and 5 folded between the rig arms 2 and 3 in the area of the hinged joint C. With these measures, the rig arm 2 serves both a guiding function during the ground-level concreting and a projecting function to overcome obstacles at the ground level and over several stories while permitting the successive rig arms 3, 4 and 5 to be used independent of the arm 2 to guide the hose parallel from their extended position directly to the obstacle being overcome with only a small unfolding height required. Further uses are made possible by the hinged joint D and/or the hinged joint E which each have an angle of traverse of approximately 270°. In order to reduce the projection of the rig laterally and to thus improve its entry characteristics during introduction into narrow openings, a further advantageous development of the invention is suggested wherein all pipe sections and the associated pipe rotating joints each are arranged on the same side of the rig arm. With this arrangement, expensive rotary transmissions of the pipe rotating joints through the hinged joints are not needed. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be discussed hereinafter in greater detail in connection with the drawings, in which: FIG. 1 is a side view of a mobile concrete pump illustrated with a five-arm concrete-distribution rig in the folded travelling position; FIGS. 2a and 2b illustrate the mobile concrete pump according to FIG. 1 during travel into a hall of a factory and during ground-level concreting in this hall; FIG. 3 illustrates the mobile concrete pump according to FIG. 1 during concreting in buildings, which are several stories high, and during concreting after overcoming an obstacle; FIGS. 4a to 4c illustrate a side view and front view of the concrete pump according to FIG. 1 with an end-hose manipulator mounted on the concrete-distribution rig for filling tunnel forms, and illustrate an enlarged side view of the end-hose manipulator. DETAILED DESCRIPTION The mobile concrete pump illustrated in the drawings has a chassis 10, a pivot-bearing block 16 arranged near the front axle 12 and the cab 14 of the chassis 10, a distribution rig 20 rotatable at 360° about a vertical axis 18 on the pivot-bearing block 16, a hydraulically driven concrete pump 24, which can be loaded with concrete through a material-feeding container 22, and a feed pipe 28 connected to the concrete pump 24 through a pipe switch 26. The distribution rig 20 has five rig arms 1, 2, 3, 4 and 5, wherein a rig arm 1 is connected at the pivot joint A to the pivot-bearing block 16 and rig arms 1, 2, 3, 4 and 5 are connected with one another at the respective hinged joints B, C, D and E. The folding in and out of the rig arms 1 to 5 about the joints A to E is accomplished hydraulically by means of double-acting hydraulic cylinders 30, which are hinged at their cylinder ends and rod ends to booms or folding bars of either the rig arms 1 to 5 or the pivot-bearing block 16. The pivot joint A has a swivelling range of motion of 90° to 100° the hinged joints B and C of approximately 180° and the hinged joints D and E of approximately 270°. The rig arms 1 to 5 may be stored in the travelling position shown in FIG. 1 wherein the rig arms 1 to 5 are folded against one another so as to be aligned essentially parallel to one another, so that the rig arms 2, 3, 4 and 5 rest under the main arm 1. The rig arms 1, 2 and 3 are folded at their hinged joints B and C in opposite rotational directions so as to be folded against one another like a Z. The rig arms 3, 4 and 5, however, are folded against one another at their hinged joints D and E each in the same rotational direction such that the rig arms 4 and 5 are folded relative to the rig arms 2 and 3 in a manner similar to rolling, i.e. roll folding. FIGS. 2a and 2b show the operation of the mobile concrete pump in performing a ground-level concreting of the floor located within a low-ceiling space, in particular within a hall 32 of a factory. The rig arms 2 to 5 are for this purpose first pivoted in front of the cab 14 in a downwardly folded position by lifting the main arm 1 slightly and rotating the pivot-bearing block 16. The rig arms 2 to 5 are then lowered far enough into an inclined position such that travel through the low entry gate 34 of the hall 32 of the factory is possible (left side of FIG. 2a). The rig arms 2 to 5 can be erected within the hall 32 of the factory and can be loaded by filling the feed pipe 28 with concrete (right side of FIG. 2a). After the concrete-distribution rig 20 has been unfolded, as seen in FIG. 2b, the concreting of the floor starts at the point farthest away from the vehicle, namely through the flexible end hose 36, which hangs down at the free end of the rig arm 5 and which is directed toward the areas to be concreted by the operator. It is possible by suitably moving the rig arms 1 to 5 about their respective joints A to E to move the end hose 36 along an operating line L parallel with the floor until the end hose 36 is directly in front of the cab 14. Due to the special arrangement and the swivelling ranges of motion of the hinged joints B to E, the height H required to unfold the distribution rig 20 is only a little higher than the operating line L, through which the free end of the end arm 5 is manipulated. Only a few simple sequences of movement are then needed when the end hose 36 is in the end position near the cab shown in FIG. 2b, in order to move the rig arms 2 to 5 into their folded position shown on the right side in FIG. 2a. The special characteristics of the above-described five-arm concrete-distribution rig 20 can be seen most of all in the movement analysis illustrated in FIG. 3. Thus it is possible during the ground-level concreting to use the arm 2 together with the arm 1 to overcome obstacles 38, for example, partition walls, hall structures and the like, whereby the arms 3 to 5 independent of the arm 2 can be manipulated between their extended position and a position proximate the obstacle 38 for guiding of the end hose 36. A similar situation exists when concreting higher floors, where the arm 2 together with the arm 1 is used to bridge distances in a vertical direction. These concreting tasks, which are often encountered in practice, cannot be solved with the conventional concrete-distribution rigs. As is shown in FIGS. 4a to 4c, the described mobile concrete pump also can be utilized for concreting tunnels, when the end rig arm 5 also is equipped with a hydraulically operable and/or motor operable end-hose manipulator 40. The end-hose manipulator 40 can be connected to the last pipe section 46 of the end arm 5 of the concrete-distribution rig 20 by a rigid pipe piece 42 and a pipe rotating joint 44. The pipe piece 42 has a support structure 58 at its front end to which a hydraulic cylinder 48 is pivotally supported and aligned essentially parallel with respect to an axis of the pipe piece 42. The flexible end hose 36 is connected at the front end of the pipe piece 42 and includes a sleeve 50 designed as a clamping bar in its end-side third section. The sleeve 50 has lateral pivot bearings 52, to which the fork-shaped weight arm 54 of a two-arm rocking lever 56 is hinged. The rocking lever 56 is pivotally supported about an axis 60, which is parallel to a common axis between the pivot bearings 52, at the end of a support construction 58 extending essentially axially beyond the pipe piece 42. The rocking lever 56 is connected to the piston rod 64 of the hydraulic cylinder 48 at its power arm 62, which is angled with respect to the weight arm 54. By operating the hydraulic cylinder 48, the rocking lever 56 can be pivoted at an angle of approximately 60°. This pivoting movement is transferred into a bending of the end hose 36 whereby the connecting piece of the end hose 36 projecting over the sleeve 50 moves through an effective angle of traverse of 90°. A housing 66 for receiving a hydraulic motor 68 furthermore is arranged on the pipe section 46 wherein the drive shaft 70 of the hydraulic motor 68 can be coupled with the pipe piece 42 through a chain drive 72. The pipe piece 42 can thus be rotated relative to the pipe section 46 by the motor 68 into any desired rotary position. The rotating and tilting movement of the end hose 46 is done through hydraulic control of the hydraulic motor 68 and of the hydraulic cylinder 48 through the control valves 74 arranged in the housing 66 where the control is provided with the help of a remote control, which is not illustrated. Thus it is possible to connect the end hose 36 to the successive concreting nozzles or windows 76 of a tunnel form 78 by suitably operating the distribution rig 20 and the end-hose manipulator 40. In conclusion the following must be stated: The invention relates to a five-arm concrete-distribution rig 20 mounted on a vehicle, the rig arms 1, 2 and 3 of which can be folded together in opposite rotational directions at their hinged joints B and C, which have a pivoting range of motion of approximately 180°, to form a Z shape. In order to make it possible to supply concrete through the parallel end hose over obstacles and into upper floors, the rig arms 3, 4 and 5 of the invention can be roll folded together at their joints D and E, which have a pivoting range of motion of approximately 270°, wherein each rig arm rotates in the same rotational direction relative to the rig arms 2 and 3 within the area of their hinged joint C. Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.	The invention concerns a five-arm concrete-distribution rig (20) mounted on a vehicle. Arms (1, 2 and 3) can be folded together by pivoting in opposite directions about hinged joints (B and C), which are capable of pivoting through approximately 180°, to form a "Z". In order to make it possible to supply concrete through several hoses in parallel, to upper stories and over obstacles, the invention proposes that arms (3, 4 and 5) can be folded together by pivoting in the same direction about joints (D and E), which are capable of pivoting through approximately 270°, to bring them up against arms (2 and 3) in the vicinity of hinged joint (C).
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS REFERENCE TO RELATED APPLICATIONS [0001] This is a continuation-in-part of currently pending U.S. patent application Ser. No. 14/244,091, entitled “DOOR COLLAR LOCK”, filed Apr. 3, 2014, which is a continuation-in-part of abandoned U.S. patent application Ser. No. 14/099,912, entitled “DOOR COLLAR LOCK”, filed Dec. 7, 2013. FIELD OF THE INVENTION [0002] The present invention generally relates to a door collar lock. More specifically, the invention relates to a system and method for securing a door in a closed position using a door collar locking device. BACKGROUND OF THE INVENTION [0003] The use of door closing mechanisms having a rod and associated piston operating within a cylinder is well known. For instance, in residential applications, it is well known to connect such a mechanism between the door and its frame to act as a shock absorber or dampener against the action of a closing force such as a spring or a partial vacuum within the cylinder. [0004] It has been known to provide different types of stops in conjunction with such closing mechanisms, which allow the door to be closed only partially, thereby temporarily maintaining the door in the desired position against the closing force. One of the more common types of prior art devices consists of a stop washer mounted on the piston rod. The washer is wedged between the rod and the cylinder to prevent the rod from being drawn in to the cylinder. [0005] While different ways of temporarily keeping a door having a pneumatic piston and rod mechanism open have been contemplated and made available, few systems have focused on keeping a door with a pneumatic piston and rod closed for emergency purposes. [0006] Recent tragic events such as those at Sandy Hook Elementary School in Connecticut, Columbine High School, and other locations, have prompted discussions on ways to improve security in schools and in other venues. In some instances, due to fire code regulations, and the like, the use of door locks may be disallowed. Still, even door locks may be vulnerable to forced entry because typical door locks are easily kicked-in or pushed open by blunt and sudden force. [0007] Therefore, there is still a need for a system and method that overcomes the shortcomings of the above-mentioned prior art. The system and method described herein provides such a system and method by preventing opening of a door with a pneumatic piston and rod mechanism. SUMMARY OF THE INVENTION [0008] According to a preferred embodiment, an apparatus for holding a door closed, comprising: a top panel; a left wall; a right wall; a flap attached to the left wall opposite the top panel and folded under the apparatus; a flap attached to the right wall opposite the top panel and folded under the apparatus; a front end; a back end; and an opening at the front end that has a larger cross section than a cross section of the back end thereby providing for a tapered shape of the apparatus overall, such that the apparatus is configured to fit over two hinged arms of a door closing system, preventing the arms from articulating open to prevent the door from opening. [0009] According to another preferred embodiment, a door collar lock, comprising: a top panel; a left wall; a right wall; a front end; a back end; a flap attached to the left wall opposite the top panel and folded under the apparatus; a flap attached to the right wall opposite the top panel and folded under the apparatus; and an opening at the front end that has a larger cross section than a cross section of the back end thereby providing for a tapered shape of the door collar lock overall, such that the door collar lock is configured to fit over two hinged arms of a door closing system, preventing the arms from articulating open to prevent the door from opening. [0010] According to another preferred embodiment, a method for creating a customized apparatus for holding a door closed, comprising comparing a physical door hydraulic piston to two or more diagrammatic configurations to determine which of two or more computer aided design templates to use in fabrication; measuring a straight arm of the physical door hydraulic piston to produce a measurement M 1 ; measuring from the outside edge of the straight arm to an outside edge of an angled arm of the hydraulic piston to produce a measurement M 2 ; measuring a width of a pivot point of the hydraulic piston to produce a measurement M 3 ; measuring the collective height of the straight arm and the angled arm to produce a measurement M 4 ; selecting one of the templates from the two or more templates based on the comparing step; entering measurements M 1 , M 2 , M 3 and M 4 into the selected template to produce fabrication specifications; based on the fabrication specifications, fabricating a customized apparatus for holding a door closed, comprising: top panel; a left wall; a right wall; a flap attached to the left wall opposite the top panel and folded under the apparatus; a flap attached to the right wall opposite the top panel and folded under the apparatus; a front end; a back end; and an opening at the front end that has a larger cross section than a cross section of the back end thereby providing for a tapered shape of the apparatus overall, such that the apparatus is configured to fit over two hinged arms of a door closing system, preventing the arms from articulating open to prevent the door from opening. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 is a right front perspective view of a door collar lock according to one exemplary embodiment of the present invention; [0012] FIG. 2 is a top elevational view of the embodiment of FIG. 1 ; [0013] FIG. 3 is a left perspective view of a door with the door collar lock according to the embodiment of FIG. 1 . [0014] FIG. 4 is a bottom right perspective view of a door with the door collar lock according to the embodiment of FIG. 1 . [0015] FIG. 5 illustrates a door collar lock according to an alternative embodiment of the present invention. [0016] FIG. 6 illustrates a door collar lock according to another alternative embodiment of the present invention. [0017] FIG. 7 illustrates according to another alternative embodiment of the present invention. [0018] FIG. 8 illustrates according to another alternative embodiment of the present invention. [0019] FIG. 9 illustrates a door collar lock according to another alternative embodiment of the present invention. [0020] FIG. 10 illustrates a door collar lock according to other alternative embodiment of the present invention. [0021] FIG. 11 illustrates a door collar lock according to another alternative embodiment of the present invention. [0022] FIG. 12 is a bottom, front perspective view of a door collar lock according to another alternative embodiment of the present invention. [0023] FIG. 13 is a bottom left perspective view of the embodiment of FIG. 12 ; and [0024] FIG. 14 is a left perspective view of a door having a door collar lock according to the embodiment of FIGS. 12 and 13 . [0025] FIG. 15 is a full-front elevational view of typical door with a door collar lock according to the present invention. [0026] FIG. 16 is a flow diagram that illustrates steps performed in a process to make a customized door collar lock according to the present invention. [0027] FIG. 17 is a diagram illustrating two possible left mount hydraulic configurations. [0028] FIG. 18 is a top elevational view of the hydraulic arm configuration shown in FIG. 17 . [0029] FIG. 19 is another top elevational view of the hydraulic mount configuration in FIG. 17 . [0030] FIG. 20 is another top elevational view of the hydraulic mount configuration in FIG. 17 . [0031] FIG. 21 is a side view of the mount configuration of FIG. 17 . DETAILED DESCRIPTION OF THE INVENTION [0032] The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. [0033] Various inventive features are described below that can each be used independently of one another or in combination with other features. [0034] Broadly, embodiments of the present invention generally provide a door collar lock that can be easily installed over the rods of a pneumatic door mechanism to prevent entry. With reference to FIG. 1 , a right front perspective view of a door collar lock 10 is shown according to one embodiment. In one embodiment, the door collar lock 10 may comprise a front end 8 , a back end 9 , a left wall 4 (having an inner wall 2 ), and a right wall 3 (having an inner wall 1 ). The front end 8 may comprise an opening 5 , which may have a planar area that may be smaller than the cross section of the front end 9 , providing for a tapered shape of the door collar lock 10 overall. [0035] The relative triangular shapes of a top panel 6 of the door collar lock 10 , and a bottom panel 7 illustrate the tapering from back to front of the door collar lock 10 , as also illustrated in the partial view of the inner wall 11 of the bottom panel 7 . [0036] With reference to FIG. 2 , a top elevational view of the door collar lock 10 of FIG. 1 is shown. The tapered shape of the door collar lock 10 is illustrated in FIG. 2 , more specifically as illustrated by the shape of the top panel 6 . [0037] With reference to FIG. 3 , a left perspective view of a door 30 with a pneumatic or spring actuated arm and rod configuration is shown, with the door collar lock 10 installed to prevent the door 30 from opening according to the embodiment of FIG. 1 . The rod or elbow 22 a and 22 b may consist of two articulating elongated members 22 a and 22 b over which the door collar 10 may be fitted by insertion over the elongated members 22 a and 22 b. Normally, the two elongated members 22 a and 22 b are free to articulate as allowed or caused by the pneumatic, hydraulic, or spring piston 20 . While the piston 20 may bias the elongated members 22 a and 22 b to push the door 30 into the closed position with respect to the door frame 32 , such a bias toward closing does not function as a lock. A person of average or low strength may still push the door open with little or no effort, as designed. However, in an emergency situation, it may be desirable to push the door collar lock 10 over the arms 22 a and 22 b. [0038] With reference to FIG. 4 , a bottom right perspective view of the door collar lock 10 installed to prevent the rods 22 a and 22 b from scissoring outwardly to a more oblique angle α so as to prevent opening of the door 30 is shown. The rods 22 a and 22 b are shown in phantom for the portion covered by the door collar lock 10 , and the hinge 26 between the rods 22 a and 22 b is further illustrated in phantom. The door collar lock 10 functions to keep the rods 22 a and 22 b at a relatively more acute angle β rather than when the door 30 is in the open position with respect to the frame 32 . In one embodiment, the angle β comprises an angle by which the door 30 is substantially in a closed position with respect to the door frame 32 , so as to prevent entry by a potential wrong doer in an emergency. In one embodiment, the angle α comprises a wider angle than angle β, so as to prevent or deter a wrong doer from entry in an emergency. [0039] As shown in FIG. 4 , the elongated design of the sides 3 and 4 of the door collar lock 10 functions to provide a distributed pressure along some or most of the length of the rods 22 a and 22 b when there is attempt to force the door 30 open. Having this elongated length and pressure along the rods 22 a and 22 b, as opposed to just one small portion of the rods 22 a and 22 b, makes for a more rigid stoppage of the door 30 from opening. The larger area of distribution of the pressure along the sides 3 and 4 , and the planar surface areas of the top ( 6 in FIGS. 1 and 2 ) and bottom 7 of the door collar lock 10 further provides more rigidity. [0040] Put another way, the left wall 3 and the wall 4 are configured at an angle with respect to each other so as to contact a relative substantial part of side surface areas of the arms 22 a and 22 b for increased distribution of force placed by the arms on the apparatus 10 as opening force is placed on the door 30 . In this respect, the top 6 and bottom 7 comprise solid substantially triangular plates so as to further distribute the force placed on the apparatus 10 by the arms 22 a and 22 b as opening force is placed on the door 30 . [0041] FIGS. 5-9 illustrate various embodiments that provide for various storage solutions for the door collar lock 10 . Storage at or in the general area of the door collar lock 10 may prevent, for example, a teacher in a classroom, or manager in an office, from having to search for the door collar lock 10 in an extreme panic during an emergency. For example, with specific reference to FIG. 5 , an alternative embodiment of the door collar lock 10 includes wheels 50 on small carriages configured to roll along a mount on the door frame 32 , on the side of one of the rods 22 a and 22 b, or on one of the rods 22 a itself. The door collar lock 10 can then be stored to the side of the rods 22 a and 22 b when not in use, but then rolled into position when the door 30 is closed, over both of the rods 22 a and 22 b, during an emergency when in use, as shown in position in FIG. 5 . [0042] With reference to FIG. 6 , yet another alternative embodiment of the door collar lock 10 is shown with one or more magnets 60 attached to the top 6 as a mounting mechanism. In this embodiment, the door collar lock 10 may be magnetically attached to a steal structure, such as the door 30 or door frame 32 when not in use, but remain easily accessible during an emergency. [0043] With reference to FIG. 7 , yet another alternative embodiment of the door collar lock 10 is shown with one or more wall mounting holes 70 located in the top 6 as a mounting mechanism. As with the magnets 60 in FIG. 6 , the wall mounting holes 70 allow the door collar lock 10 to be position mounted in proximity to the door 30 by means of one or more nails or mounting brackets in the door 30 or wall near the door. [0044] With reference to FIG. 8 , yet another alternative embodiment of the door collar lock 10 is shown with a mounting hook 64 located in the top 6 as a mounting mechanism. The wall-mounting hook 64 allows the door collar lock 10 to be position mounted in proximity to the door 30 by means of a nail or mounting bracket in the door 30 or wall near the door. [0045] With reference to FIG. 9 , yet another alternative embodiment of the door collar lock 10 is shown with a knob 66 to allow for more clearance for the hinge 26 within the device 10 when mounted on the elbows or arms 22 a and 22 b. [0046] With reference to FIG. 10 , yet another alternative embodiment of the door collar lock 10 is shown with a bevel 70 that may allow the device 10 to be more easily tightened around smaller sized arms 22 a and 22 b. [0047] With reference to FIG. 11 , yet another alternative embodiment of the door collar lock 10 is shown with an extension or insert 16 having a ridge configured to slide into the opening 5 of the device 10 to extend the length of the device 10 for adjustment for shorter or longer arms 22 a and 22 b. After the extension 16 is inserted into the opening 5 , the arms 22 a and 22 b are fit through the extension's opening 15 . [0048] With reference to FIG. 12 , a bottom, front perspective view of an alternative embodiment of the door collar lock 10 is shown. The embodiment of FIG. 12 may comprise an embodiment that eliminates any need for welding of the door collar lock 10 . Instead of a having a solid bottom panel 7 as in the embodiments of FIGS. 1-11 , the embodiment of FIG. 12 has a portion of the bottom panel cut out, with instead, two flaps 50 that extend from the sides 3 and 4 of the lock 10 , bent into the bottom of the lock 10 . [0049] With reference to FIG. 13 , a bottom left perspective view of the embodiment of FIG. 12 is shown. The top 9 of the door collar lock 10 may comprise an end cap 52 that is extended from the bottom panel 7 , and which may not be directly connected to the sides 3 and 4 of the lock 10 for ease of manufacturing, which may result in slits 60 down the sides of the end cap 54 between the sides 3 and 4 and the end cap 54 . Optionally, the end cap 54 may be attached, welded, or glued to the sides 3 and 4 after shaping of the lock 10 during manufacturing. [0050] The embodiment of FIGS. 12 and 13 may allow the door collar lock 10 to be made by brake-pressing it. The whole pattern can be laid flat (from one geometric shape) and cut by a laser. Next, a brake machine may make five brakes to fold the finished brake press lock 10 . There may be, for example, one brake for the end cap 54 , and another brake for each side 3 and 4 , and another two breaks to fold the flaps 52 that form the open channel on the bottom. This embodiment may cut down significantly on costs of manufacturing, without compromising strength. In this respect, in one embodiment, it may be advantageous to use a gauge of steel of sufficient thickness for the rigidity to cause toe creases or brakes in the lock 10 to remain substantially permanent during use to hold when the lock 10 is put under duress. [0051] With reference to FIG. 14 , a left perspective view of a door with a pneumatic or spring actuated arm and rod configuration, with the embodiment of FIGS. 12 and 13 installed to prevent the door from opening is shown. As shown in FIG. 14 , even in the absence of a solid bottom 7 as with the embodiment of FIG. 3 , the flaps 52 still provide enough force over the arms 22 a and 22 b to prevent a person from pushing the door open when the embodiment of FIG. 14 is installed over the arms 22 a and 22 b, functioning in the same way as the embodiment of FIG. 3 . [0052] Method and System For Customization [0053] With reference to FIG. 15 , a full-front elevational view of typical door with a hydraulic, or spring piston 20 to bias the elongated members (e.g. 22 b ). In a system and method for customization, a first step may be to locate the position of the hydraulic piston 20 where the door collar lock 10 may be installed, as indicated by the circle 95 . [0054] In this regard, this first step may also be thought of as the first step to customizing a door collar lock 10 . With reference to FIG. 16 , a flow diagram illustrates steps performed in a process to make a customized door collar 10 according to one embodiment. In step 402 , a potential user (customer) of the door collar 10 may determine location or position of the hydraulic piston 20 (as illustrated in FIG. 15 by the circle 95 ). [0055] In step 406 , the customer may compare their door and hydraulic piston configuration to a diagram of left and right pictorial configurations. With reference to FIG. 17 , two possible left mount hydraulic configurations are shown. For example, there may be an A configuration 200 of the left mount hydraulic arm, and a B configuration 202 , by which the user can view his or her hydraulic arm 20 and selected from the A configuration 200 and B configuration 202 . [0056] Referencing back to FIG. 16 , in step 406 , the customer may then take a measurement of the straight arm 22 a that is substantially parallel to the door 30 (when the door is in the closed position). With reference to FIG. 18 , a top elevational view of the model A type hydraulic arm 20 is shown, with indications M 1 of where the customer should measure the straight arm 22 a that is substantially parallel to the door 30 . In step 406 , the measurement M 1 is the length of the straight arm 22 a, starting at the outside edge of the pivot point or hinge 26 to a half inch to one inch before the first obstruction (bend or closer box). [0057] In step 408 , the customer may perform an open sleeve measurement. With reference to FIG. 19 , another top elevational view for the hydraulic arm of FIG. 18 showing where the customer should measure a length of the open sleeve M 2 . The measurement M 2 is for the opening of the door collar 10 . The customer may measure from the outside edge of the straight arm 22 a to the outside edge of the angled arm 22 b. In one embodiment, for the most accurate measurement, the customer may make the tape measure or ruler completely perpendicular to the door 30 to provide a snug fit for the door collar 10 . [0058] With reference back to FIG. 16 , in step 410 , the user may measure the width of the pivot point or hinge 26 . With reference to FIG. 20 , another top elevational view for the hydraulic arm 20 of FIG. 18 showing where the customer should measure a length of the pivot or hinge 26 is shown. The customer may measure the length as shown by M 3 of FIG. 20 . [0059] With reference back to FIG. 16 , in step 412 , the user may take the measurement of the thickness or collective height of the two closer arms 22 a and 22 b at a thickest point (usually at the hinge). With reference to FIG. 21 , front elevational view for the hydraulic arm 20 of FIG. 18 showing where the customer should measure the two closer arms 22 a and 22 b is shown. This measurement M 4 may be from the highest and lowest points of the closer arms 22 a and 22 b. If a nut or knob 180 adds thickness to the arms 22 a and 22 b, then the measurement M 4 may include this thickness. [0060] In step 414 , the customer may transmit the measurements to the manufacturer. Transmission may be through electronic means, or by filling out an HTML form on the internet. [0061] In step 416 , the manufacturer may take the received measurements, M 1 , M 2 , M 3 , and M 4 , and plug them into a CAD template. CAD templates are widely available as known by those of skill in the art. They allow manufacturers to create a template of a device, and devise different sizes by defining measurements of certain parts of the template in the CAD system. The CAD system can then proportionally and automatically re-size the CAD object, and produce fabrication specifications for the fabrication machine or fabricator, which may using, by way of example, and not by way of limitation, lazar cutting of metal to produce the object. Such CAD systems that allow this type of templating are available from many sources, including PTC Creo by PTC, Inc. of Needham, Mass. 02494, USA. [0062] With reference to FIG. 20 , a CAD template 300 that may be used for customization of the door collar lock 20 is shown. A template table 350 may provide an entry interface for entering the received measurements M 1 , M 2 , M 3 , and M 4 . The template may then adjust the proportional sizes of the object in the template to produce a manufacturing fabrication file, for example, in the form of a drawing interchange format or drawing exchange format (DXF) that can be used by the fabrication machinery to produce the door collar lock 20 . [0063] It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.	A method for creating a customized apparatus for holding a door closed comprises comparing a physical door hydraulic piston to two or more diagrammatic configurations to determine which of two or more computer aided design templates to use in fabrication. A straight arm of the physical door hydraulic piston is measured to produce a measurement M 1. A user measures from the outside edge of the straight arm to an outside edge of an angled arm of the hydraulic piston to produce a measurement M 2. A user measures a width of a pivot point of the hydraulic piston to produce a measurement M 3. A user measures the collective height of the straight arm and the angled arm to produce a measurement M 4. A user selects one of the templates from the two or more templates based on the comparing step. A CAD operator enters measurements M 1, M 2, M 3 and M 4 into the selected template to produce fabrication specifications. Based on the fabrication specifications, a customized apparatus is fabricated for holding a door closed.
You are an expert at summarizing long articles. Proceed to summarize the following text: This application is based upon and claims priority from U.S. Provisional application Ser. No. 62/008,879, which is incorporated herein by reference. BACKGROUND OF THE INVENTION Field of the Invention Applicants' invention relates to a device for magnetic anti-tampering system. More particularly, it relates to magnetically paired keys and locks that use lever tumblers. Background Information There are many keys for many different types of locks. One type of lock and key commonly used in prisons and correctional facilities is the paracentric. Paracentric literally means to deviate from circularity, or changing the distance from a center. A paracentric key is distinguishable by the heavily contoured shape of its blade, which protrudes past the center vertical line of the keyway in the cylinder. Locks with paracentric keyways offer a higher level of protection against picking since they prevent direct access to the pins by traditional picking tools. A paracentric lock has a keyway with one or more wards on each side projecting beyond the vertical center line of the keyway. Instead of the wards on the outer face of the lock simply protruding into the shape of the key along the spine, the wards protrude into the shape of the key along the entire width of the key, including along the length of the teeth. The shape and wards of the paracentric lock and key are designed to hinder picking. This is the reason that person could locks and keys are often used in jails. However, even the paracentric lock and keys are not completely immune to picking by motivated individuals such as inmates. A pin tumbler lock is a lock mechanism that uses pins of varying lengths to prevent the lock from opening without the correct key. Pin tumblers are most commonly employed in cylinder locks, but may also be found in other types of locks as well. Pin tumbler locks are made up of a Bible which sits around a cylindrical plug. Unimpeded, the plug will rotate inside the Bible. The Bible of the lock contains the springs and the driver pins. The driver pins sit between the Bible and the plug of the lock. The plug is the portion of the lock that contains the keyway and will turn when the correct key is inserted. Below the driver pins are the key pins. The key pins will actually touch the key when it is inserted. The driver pins and the key pins are in contact and a thought one another but are not connected. All of the pins slide within a cylinder with the springs urging the pins down. The driver pins and springs are all the same length. In contrast, each of the key pins has a unique length that corresponds to the unique cuts (teeth) in the key. When no key is in the keyway, the springs urge the driver pins past the junction of the Bible and plug, thus the driver pins block rotation of the plug. If an incorrect key is inserted into the lock, then the lock teeth will either be too short or too tall. If a key tooth is too big, then the driver pin/lock pin combination is moved against the spring such that the lock pin extends beyond the junction of the Bible and plug and the lock pin blocks rotation of the plug. If a key tooth is too small, then like when there is no key at all, the spring urges the lock pin past the junction of the Bible and plug again blocking rotation of the plug. Of the Bible and plug is called the sheer line. When the correct key is inserted into the lock, the key pins are raised by the teeth such that the top of the key pins and the bottom of the driver pins sit at the sheer line. This allows the plug to rotate and disengage the lock. In contrast to the pin tumblers, a lever tumbler lock is a type of lock that uses a set of levers (instead of pins) to prevent the bolt from moving in the lock. In the simplest of these, lifting the tumbler above a certain height will allow the bolt to slide past. In a double acting lever lock a slot is cut in the lever so that the lever must be lifted to a certain height but not too far in order for the bolt to be allowed to move within the lock. The number of levers may vary, and may be increased in order to provide correspondingly increased levels of security. In the past, magnetic keys have been used with pin tumbler type locks. A magnetic-coded lock uses pins in combination with magnets to prevent unlocking with non-matching keys by teething and magnetic polarity. Magnetic locks/keys use paired magnets with opposing poles inside the key and plug. When a correctly matched key is inserted into the lock, not only are all the mechanical pins pushed into the correct positions, the magnetic pins are also driven to the appropriate level by the magnetic force inside the key. Magnetic-coded locks offer heightened security because in order to unlock a lock not only must the key teething fit with the pins, the magnetic pin locations and poles of the lock and key must correspond. The correct fitting position can be found by feeling the effect of the magnetic force, or by aligning with the markings. When the magnetic key is placed on a magnetic lock, the lock magnets online the magnetic catches arranged in a freely rotatable manner in relation to the key magnets such that the opposite poles oppose each other. Further, the lock magnets are pulled by the key magnets into locked positions. This occurs because the attractive force acting between the lock magnets and the key magnets is slightly greater in the online edition and the attractive force acting between the lock. If there is no magnetic key or respectively corresponding external magnetic force, the magnetic attraction of the key magnets combined so that the magnetic catches independently pull themselves into the locked position. This is in addition to the spring mechanisms of the pin tumbler locks. SUMMARY OF THE INVENTION The present invention incorporates magnets into lever tumbler and paracentric locks. The present invention provides a novel apparatus that will increase the difficulty in picking a lever tumbler, paracentric lock. The magnetic anti-tampering system of the present invention provides a mechanical and magnetic security system. It utilizes a modified paracentric key and a locking assembly affixed to a component inside of a paracentric lock. The present invention increases the security of a pair centric lock by defeating the unauthorized operation of pair centric locks by unauthorized users, such as inmates, who have fabricated copies of the authentic, paracentric keys. Paracentric locks and keys are the most common type of locks used in jails, state prisons, and detention facilities. Thus, the present invention is particularly adapted for prison and correctional facility door locks. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective, exploded view of lever tumbler lock. FIG. 2 is a perspective, exploded view of the locking assembly. FIG. 3 a is a perspective view of the locking assembly attached to the lock bolt. FIG. 3 b is a perspective, cutaway view of the carriage assembly illustrating the locked position. FIG. 4 is a perspective, cutaway view of the carriage assembly illustrating the unlocked position. FIG. 5 is a perspective view of a paracentric key with embedded magnets. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the figures, FIG. 1 illustrates the parts of a lever tumbler, magnetic paracentric lock 10 . The magnetic paracentric lock 10 has a lock case 20 that has a generally hollow interior. The lock case 20 has a back 22 and sides 24 that enclose most of the sides of the lever tumbler lock 10 . The lock case 20 has attachment apertures 34 in the back 22 that allow the lever tumbler lock 10 to be attached to a wall or door using fasteners 36 , such as screws, bolts, welds, or other attachment means as are well-known in the industry. The lock case 20 has a bolt aperture 26 that is sized to allow a lock bolt 28 to slide through. The lock bolt 28 has an engagement end 30 and a locking end 32 . The engagement end 30 is generally thicker than the locking end 32 . The engagement end 30 is sized to slide through the bolt aperture 26 . Ideally, the tolerance between the engagement end 30 and the bolt aperture 26 is kept to a minimum. The locking end 32 has a horizontal rail 38 attached that extends generally perpendicularly to the lock bolt 28 . A tumbler set 40 is also rotatably attached in the interior of the lock case 20 . The tumbler set 40 is comprised of a multiplicity of levers 42 . Each lever 42 is generally rectangularly shaped with a first end 42 a that is rotatably attached to the interior of the lock case 20 . The first end 42 a is also attached to a spring mechanism 44 that when engaged with the interior of a lock case 20 side 24 , tends to urge the second end 42 b of the lever 42 toward a locked position. The second end 42 b has and activation cutout 46 that has a channel 50 through the front of the second end 42 b that is sized to allow the horizontal rail 38 to move horizontally through the activation cutout 46 and channel 50 , consequently allowing the lock bolt 28 to slide through the bolt aperture 26 so as to lock or unlock the subject door. Interior to the activation cutout 46 is a stop cutout 48 that is sized to allow the horizontal rail 38 to move vertically to a position away from the channel 50 . Thus, if a lever 42 is raised too high, or lowered too low, then the channel 50 will not line up with the horizontal rail 38 and the stop cutout 48 holds the lock bolt 28 from sliding through the bolt aperture 26 . If all of these levers 42 are set to the correct position (presumably by the teeth of a key 100 ) then the horizontal rail 38 will line up with the channel 50 allowing the lock bolt 28 to slide through the bolt aperture 26 . Mechanically engaged with the tumbler set 40 is a key cylinder 60 . The key cylinder 60 works similarly to the pin tumbler lock with the Bible and plug as described above except that instead of moving the pins, a key 100 turns and its teeth act to position the levers 42 . The lock bolt 28 , tumbler set 40 , and key cylinder 60 are enclosed in the interior of the lock case 20 by a lock cover 70 which is attached by fasteners 36 to the lock case 20 . The lock cover 70 has a key aperture 72 that allows access with a key 100 to the key cylinder 60 . The key aperture 72 may be shaped and sized in order to admit a paracentric key 100 . FIG. 2 shows an exploded view of the magnetic locking assembly 80 . The magnetic locking assembly 80 also fits in the interior of the lock case 20 . The magnetic locking assembly 80 is comprised of magnets 82 . These magnets 82 are anticipated to be neodymium type magnets, but are not required to be. “Neodymium” refers to magnets that are a type of rare-earth magnet. They are considered a permanent magnet made for the alloy of neodymium, iron, and boron. Permanent magnets are those made from materials that are magnetized and create their own persistent magnetic fields. The neodymium magnets 82 are embedded in a locking dog 84 . The locking dog 84 is attached to a locking carriage 86 by means of a pin or second fastener 90 . A connecting bracket 88 is connected to the locking carriage 86 opposite from the locking dog 84 . A third fastener 92 connects the connecting bracket 88 and locking carriage 86 to the lock bolt 28 in the interior of the lock case 20 . The locking assembly 80 holds the neodymium magnets 82 in magnetic communication with a magnetic key 100 inserted into the key cylinder 60 . The pin or second fastener 90 may be a hardened steel pin. The pin or second fastener 90 allows the locking dog 84 to rotate or rock while connected to the locking carriage 86 . A compression spring 94 is secured to the locking carriage 86 by the third fastener 92 . FIG. 3 a shows the positioning of the locking assembly 80 attached to the lock bolt 28 . FIG. 3 b illustrates how the connecting bracket 88 allows the locking assembly 80 to move in a linear motion with the lock bolt 28 as the key cylinder 60 rotates. The compression spring 94 is positioned such that it maintains constant positive pressure on the locking dog 84 and keeping the key cylinder 60 in the locked position until unlocked with the correct magnified key 100 . FIG. 4 illustrates how when the locking dog 84 is moved to the unlocked position by use of a magnetized paracentric key 100 , the key cylinder 60 is allowed to rotate and unlock the lock. FIG. 5 illustrates a portion of a magnetic paracentric key 100 . The basic parts of a key include a head or bow which provide a portion of the key for the user to hold, a shank or blade across which are the millings, grooves, bits, teeth and the like that are specific for a lock, a at the junction of the bow and blade controls how much of the blade will enter a lock, and the tip at the opposite end of the shank from the bow. In FIG. 5 , a portion of the shank 102 is illustrated with bits 104 and groove 108 that can be made specific for an individual paracentric key cylinder 60 . In order to make the magnetic paracentric key 100 specific to a magnetic paracentric lock 10 , key magnets 110 are embedded in the shank 102 of the magnetic paracentric key 100 . As with the magnets 82 embedded in the locking dog 84 , the key magnets 110 are anticipated, but not required, to be neodymium type, permanent magnets. The key magnets 110 are embedded in predetermined locations along the shank 102 in the area between the key stop (not shown) to the tip 106 . The key magnets 110 are inserted in order that one of their two ( 2 ) magnetic poles is exposed at the surface of the shank 102 . The number of magnets 82 and key magnets 110 may vary, but generally is anticipated that there will be at least three (3) magnet 82 /key magnet 110 pairs. The magnet 82 /key magnet 110 pairs are generally paired and positioned such that the adjoining poles of the pairs are the same polarity—repelling each other. While fewer pairs could be used if the magnets were of sufficient strength, it is desirable to use a multiplicity of pairs to increase the interaction between the magnet pairs as well as making a legitimate copy of the magnetic paracentric key 100 more difficult. It is anticipated that there may be more key magnets 110 embedded in the magnetic paracentric key 100 and there are magnets 82 embedded in the locking dog 84 . The paired magnets—those that are involved in repelling the locking dog 84 to the unlocked position—are referred to as “active magnets” and those that are not are referred to as “passive magnets.” Once the active magnets of a magnetic paracentric key 100 are fully inserted into a paired magnetic paracentric lock 10 , the active key magnets 110 align with the magnets 82 embedded in the locking dog 84 , thus paired the locking dog 84 will be repelled against the urging of the spring 94 and moved to the unlocked position. When the locking dog 84 is in the unlocked position the key 100 and key cylinder 60 are allowed to rotate and unlock the lock 10 . When the correct, active key magnets 110 are not inserted with the key 100 in the key cylinder 60 , the spring 94 urges the locking dog 84 against the key cylinder 60 keeping it from rotating and unlocking the lock 10 . Thus, even if a key with its teeth, bits and grooves is otherwise shaped correctly, it will not turn the key cylinder 60 if the magnets 82 and active key magnets 110 are not positioned and paired correctly. The order of the magnetic poles expose along the shank 102 of the key 100 is referred to as the magnetic sequence combination. This design feature allows for multiple magnetic sequence combinations for keys with the same keyway (lateral grooves) and combination (key cuts). In a prison setting where the present invention is anticipated to be employed the magnetic pairs and sequence can frustrate an inmate who otherwise might be able to illegally duplicate the physical shape of the key 100 . Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the inventions will become apparent to persons skilled in the art upon the reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention.	The magnetic anti-tampering system of the magnetically enhanced key and lock system provides a mechanical and magnetic security system. It utilizes a modified paracentric key and a locking assembly affixed to a component inside of a paracentric lock. The magnetically enhanced key and lock system increases the security of a pair centric lock by defeating the unauthorized operation of pair centric locks by unauthorized users, such as inmates, who have fabricated copies of the authentic, paracentric keys. Paracentric locks and keys are the most common type of locks used in jails, state prisons, and detention facilities. The locking system requires that both the teeth of the key and the magnetic pairs of the key and locking dog combine to open the lock.
You are an expert at summarizing long articles. Proceed to summarize the following text: [0001] This application claims priority from European Patent Application No. 09179271.3 filed Dec. 15, 2009. The entire disclosure of the above patent application is hereby incorporated by reference. FIELD OF THE INVENTION [0002] The present invention pertains to a conveyor belt filter device for mechanically cleaning a fluid that is polluted with solids and flows in a channel or the like, with [0003] an endless filter belt of flat, interconnected filter elements that can be respectively pivoted relative to one another about a horizontal link axis and [0004] flexible driving means that are respectively provided to both sides of the filter belt and consist, for example, of a chain drive with deflection elements and two endless drive chains, on which the filter elements are laterally mounted, as well as [0005] a framework that carries the deflection elements and the filter belt, wherein each filter element is rigidly mounted on a chain link and front surfaces of the filter element respectively feature an abutment edge that extends parallel to the link axes of the chain links, namely such that the opposite abutment edges define a filter gap formed between two filter elements. BACKGROUND OF THE INVENTION [0006] Conveyor belt filter devices of the initially cited type are also referred to as so-called “paternoster filter rakes” and primarily serve for mechanically cleaning waste water flowing in channels designed for this purpose. The waste water flows through the filter elements that remove the filtered matter unable to pass through the filter screens from the channel. Due to the design of the filter belt in the form of interconnected filter elements that are connected by means of flexible driving means mounted on both sides of the filter elements, the required relative movements between the filter elements in the deflection regions, in particular, make it necessary to provide a gap between the individual filter elements in order to realize these relative movements. [0007] Successful developments known from the state of the art already make it possible to realize such a filter gap constant regardless of the actual relative positioning of the filter elements such that the filter gap can be maintained constant in the region of the straight transport sections of a revolving filter belt, as well as in the deflection segments that are provided with a curvature radius. A conveyor belt filter device of this type is known, for example, from EP 0 676 227 A1. [0008] Although this already makes it possible to maintain a filter gap formed between two filter elements constant over the entire transport distance, it is possible, for example, that filter gaps between different filter elements are formed differently due to manufacturing tolerances of the chain and the filter bodies. Due to the inevitable elongation of the drive chain over the service life thereof, the filter gaps furthermore are regularly enlarged in a more or less continuous fashion such that the filter effect or the effectiveness of the conveyor belt filter device can deteriorate accordingly due to the increasing gap width, particularly toward the end of the service life of the driving means. [0009] In addition, the advantageous development known from aforementioned EP 0 676 227 A1 already makes it possible to maintain an adjusted filter gap constant over the distance of the conveyor belt. As explained above, the realization of a filter gap is required for constructive reasons such that the filter gap in any case represents a discontinuity in the filter surface that otherwise has the uniform hole pattern arranged in the filter elements and an exact definition of the active filter surface is only possible to a limited degree. SUMMARY OF THE INVENTION [0010] The present invention therefore is based on the objective of additionally developing a conveyor belt filter device in such a way that the above-described disadvantages resulting from the realization of a filter gap in a conveyor belt filter device are eliminated. [0011] This objective is attained according to the invention with the characteristics of a conveyor belt filter device, characterized in that the conveyor belt filter device for mechanically cleaning a fluid ( 16 ) that is polluted with solids and flows in a channel ( 14 ) or the like, with an endless filter belt ( 11 ) of flat, interconnected filter elements ( 31 ) that can be respectively pivoted relative to one another about a horizontal link axis ( 52 ) and flexible driving means that are respectively provided to both sides of the filter belt and consist, for example, of a chain drive ( 12 ) with deflection elements and two endless drive chains ( 28 ), on which the filter elements are laterally mounted, as well as a framework ( 10 ) that carries the deflection elements and the filter belt, wherein each filter element is rigidly mounted on a chain link ( 30 ) and front surfaces ( 34 , 35 ) of the filter element respectively feature an abutment edge ( 36 ) that extends parallel to the link axes of the chain links, namely such that the opposite abutment edges define a filter gap ( 41 ) formed between two filter elements, characterized in that the filter gap is provided with a gap seal ( 43 , 60 ) that on one side of the filter belt features a sealing strip ( 43 ) that covers the filter gap and is supported on the filter elements with the sealing force and on the other side of the filter belt features a prestressing device ( 55 , 65 ) that is connected to the sealing strip and serves for generating the sealing force. Additional, particular beneficial, embodiments of the invention are provided in accordance with the following subsidiary conveyor belt filter devices. [0012] In accordance with a second conveyor belt filter device embodiment of the invention, the first embodiment is modified so that the sealing strip ( 43 ) is arranged on the inflow side of the filter belt ( 11 ) and the prestressing device ( 55 , 65 ) is arranged on the outflow side of the filter belt. In accordance with a third conveyor belt filter device embodiment of the invention, the first embodiment and the second embodiment are further modified so that the front surfaces ( 34 , 35 ) of the filter elements ( 31 ) form on the inflow side of the filter belt ( 11 ) a wedge-shaped filter gap ( 41 ) with gap flanks that are arranged relative to one another in an essentially V-shaped fashion and formed by the front surfaces, and in that the sealing strip adjoins the front surfaces in a sealing fashion with its longitudinal edges. In accordance with a fourth conveyor belt filter device embodiment of the invention, the first embodiment, the second embodiment and the third embodiment are further modified so that the longitudinal edges of the sealing strip ( 43 ) are formed by a convexly designed peripheral contour of the sealing strip. In accordance with a fifth conveyor belt filter device embodiment of the invention, the first embodiment, the second embodiment, the third embodiment and fourth embodiment are modified so that the sealing strip ( 43 ) has a circular cross section. [0013] In accordance with a sixth conveyor belt filter device embodiment of the invention, the first embodiment, the second embodiment, the third embodiment, fourth embodiment and the fifth embodiment are modified so that the sealing strip has a hollow cross section. In accordance with a seventh conveyor belt filter device embodiment of the invention, the first embodiment, the second embodiment, the third embodiment, fourth embodiment, the fifth embodiment and the sixth embodiment are modified so that the sealing strip is provided with flow-through openings for the passage of the flowing fluid. In accordance with an eighth conveyor belt filter device embodiment of the invention, the seventh embodiment is modified so that the sealing strip is provided with a hole pattern such that the sealing strip acts as a filter element. In accordance with a ninth conveyor belt filter device embodiment of the invention, the first embodiment, the second embodiment, the third embodiment, fourth embodiment, the fifth embodiment, the sixth embodiment and the seventh embodiment are modified so that the sealing strip is composed of individual sealing elements that are arranged in a row. [0014] In accordance with a tenth conveyor belt filter device embodiment of the invention, the first embodiment, the second embodiment, the third embodiment, fourth embodiment, the fifth embodiment, the sixth embodiment and the seventh embodiment, the eighth embodiment and the ninth embodiment are modified so that the prestressing device ( 55 , 65 ) features a tension element ( 45 , 61 ) that is connected to the sealing strip ( 43 ) with one end and extends through the filter gap ( 41 ) in the flow direction, wherein the other end of said tension element is connected to a pressure spring element ( 46 ) that is supported on a base that bridges the filter gap on the side of the filter belt that faces away from the sealing strip. In accordance with a eleventh conveyor belt filter device embodiment of the invention, the tenth embodiment is modified so that the pressure spring consists of a dimensionally elastic plastic element. In accordance with a twelfth conveyor belt filter device embodiment of the invention, the eleventh embodiment is modified so that the plastic element is realized in a tubular or sleeve-shaped fashion. In accordance with a thirteenth conveyor belt filter device embodiment of the invention, the first embodiment, the second embodiment, the third embodiment, fourth embodiment, the fifth embodiment, the sixth embodiment and the seventh embodiment, the eighth embodiment, the ninth embodiment, the tenth embodiment, the eleventh embodiment and the twelfth embodiment are modified so that the prestressing device ( 55 , 65 ) is arranged centrally referred to the width of the filter gap ( 41 ). [0015] According to the invention, generally, a filter gap is respectively realized in the conveyor belt filter device between two adjacent filter elements, wherein said filter gap is provided with a gap seal featuring a sealing strip that covers the filter gap and is supported on the filter elements with the sealing force on one side of the filter belt. A prestressing device connected to the sealing strip is provided on the other side of the filter belt in order to generate the sealing force. [0016] Due to the inventive design of the conveyor belt filter device with a gap seal, the filter gap is effectively sealed without impairing the function of the conveyor belt filter device that requires an unobstructed movement of the filter elements over the transport distance. Since the sealing strip is prestressed against the filter element in a sealing fashion, relative movements are not only possible between the individual filter elements, but also between the sealing strip and the adjacent filter elements. In this case, the prestressing device neither impairs these relative movements nor the sealing effect of the sealing strip because it is situated on the opposite side of the filter belt referred to the sealing strip. [0017] The sealing strip arranged in accordance with the invention therefore makes it possible to seal a filter gap regardless of its actual width, as well as regardless of the fact whether this filter gap changes during a revolution of the conveyor belt or over the service life of the conveyor belt filter device and its driving means, respectively. A filter gap consequently can be regularly inhibited or sealed such that the effective filter surface actually is defined by the hole pattern of the individual filter elements only. [0018] In one preferred embodiment, the sealing strip is arranged on the inflow side of the filter belt and the prestressing device is arranged on the outflow side of the filter belt in order to ensure that the fluid flowing against the sealing strip contributes to an increase in the sealing force. [0019] It is particularly advantageous if the front surfaces of the filter elements form a wedge-shaped filter gap on the inflow side of the filter belt, wherein the gap flanks formed by the front surfaces are essentially arranged relative to one another in a V-shaped fashion, and wherein the sealing strip adjoins the front surfaces in a sealing fashion with its longitudinal edges. Due to the V-shaped arrangement of the gap flanks, it is ensured that the normal force component that acts upon the gap flanks and is decisive for the generation of a sealing force is not only realized in the deflection regions of the conveyor belt, but also in the straight transport sections. [0020] An additional increase of the sealing effect regardless of the position of the sealing strip relative to the front surfaces can be achieved, particularly with gap flanks that are formed by the front surfaces, if the longitudinal edges of the sealing strip are formed by a convexly designed peripheral contour of the sealing strip. If the sealing strip consists of a flat bar, this can already be realized by simply rounding off the longitudinal edges of the flat bar. [0021] In this context, it is particularly advantageous if the sealing strip has a circular cross section. It would naturally also be possible to consider different cross-sectional shapes or such as, for example, a triangular cross section. [0022] If the sealing strip has a hollow cross section, it is possible to limit the mass of the sealing strip to a required degree because only the type and design of the peripheral contour of the sealing strip are important for the sealing effect. [0023] In order to prevent the filter gap from being completely sealed, if so required, the sealing strip may be provided with flow-through openings for the passage of the flowing fluid, wherein the sealing strip itself may also act as a supplementary filter element, particularly if the sealing strip is provided with a hole pattern. For example, the hole pattern can be realized in accordance with the hole pattern of the filter elements such that an undesirable filter gap is inhibited by the sealing strip on one side and the sealing strip contributes to an increase of an exactly defined filter surface on the other side. [0024] In one preferred embodiment, the prestressing device features a tension element that is connected to the sealing strip with one end and extends through the filter gap in the flow direction, wherein the other end of said tension element is connected to a pressure spring element that is supported on a base that bridges the filter gap on the side of the filter belt that faces away from the sealing strip. In this way, a particularly advantageous prestressing device is realized that does not even impair gap changes occurring over the distance of the conveyor belt such that the risk of the prestressing device impairing the required relative movements between the filter elements can be largely precluded, namely even if the filter gaps change. [0025] It is also particularly advantageous if the pressure spring element consists of a dimensionally elastic plastic element such that no components that are sensitive to corrosion need to be used for realizing the pressure spring. [0026] If the plastic element is furthermore realized in a tubular or sleeve-shaped fashion, the desired effects with respect to the dimensional elasticity can be realized with particularly simple means. [0027] It is also particularly advantageous if the prestressing device is arranged centrally referred to the width of the filter gap because a reliable function of the gap seal can be achieved in this fashion with only one prestressing device and the prestressing device furthermore does not impair the flow, particularly if the gap seal or the sealing strip is realized in the form of a supplementary filter element. BRIEF DESCRIPTION OF THE DRAWINGS [0028] Preferred embodiments of the invention are described in greater detail below with reference to the drawings. [0029] In these drawings: [0030] FIG. 1 shows a side view of a conveyor belt filter device during its operation; [0031] FIG. 2 shows two filter elements that are connected to one another on both sides by means of a drive chain, as well as their relative arrangement on a longitudinal transport section and a first embodiment of a gap seal; [0032] FIG. 3 shows the filter elements illustrated in FIG. 2 viewed in the transport direction; [0033] FIG. 4 shows a sectional representation of the filter elements illustrated in FIG. 3 along the line of section IV-IV; [0034] FIG. 5 shows an enlarged detail of a filter gap formed between the filter elements illustrated in FIG. 4 ; [0035] FIG. 6 shows the filter elements illustrated in FIG. 2 in a deflection region of the transport section; [0036] FIG. 7 shows the filter elements illustrated in FIG. 6 viewed in the transport direction; [0037] FIG. 8 shows a sectional representation of the filter elements illustrated in FIG. 7 along the line of section VIII-VIII; [0038] FIG. 9 shows an enlarged detail of the filter gap formed between the filter elements in the deflection region; [0039] FIG. 10 shows two filter elements that are connected to one another on both sides by means of a drive chain, as well as their relative arrangement on a longitudinal transport section and a second embodiment of a gap seal; [0040] FIG. 11 shows the filter elements illustrated in FIG. 10 in a deflection region of the transport section, and [0041] FIG. 12 shows a sectional representation of the gap seal illustrated in FIG. 10 . DETAILED DESCRIPTION OF THE INVENTION [0042] The conveyor belt filter device illustrated in FIG. 1 features a framework 10 , a filter belt 11 that is guided on the framework 10 , a chain drive 12 that is connected to the framework 10 and the filter belt 11 and an arrangement 13 for transporting away filtered matter that is designed for cleaning a channel 14 extending below ground level 15 . [0043] A fluid 16 polluted with solids flows through the channel 14 in a flow direction 17 that is indicated by a directional arrow, wherein the channel 14 may extend perpendicular to the plane of projection with a significant width. The conveyor belt filter device extends up to a channel bottom 18 such that the entire flow cross section of the channel 14 is blocked transverse to the flow direction 17 and the fluid 16 needs to pass through the part of the conveyor belt filter device situated in the channel 14 . [0044] Due to its arrangement in the channel 14 such that the filter belt 11 is directed transverse to the flow direction 17 , the conveyor belt filter device illustrated in FIG. 1 is also referred to as a “flow-through filter belt rake.” However, the invention that is described below and defined in claim 1 may also be used in conveyor belt filter devices, in which the filter belt is directed parallel to the flow direction, wherein experts also refer to these conveyor belt filter devices as “central-flow” or “dual-flow” filter band rakes, in which the fluid flows through the filter belt transverse to the flow direction in the channel. [0045] In the present embodiment, the framework 10 consists of a lower frame part 19 that forms the part to be passed by the fluid 16 and an upper frame part 20 that is situated outside the channel 14 and serves for mounting an electromotive drive that drives a shaft 21 . A connecting frame 22 is provided between the frame parts 19 and 20 and makes it possible to stationarily lock the framework 10 to both sides of the channel 14 , for example by means of screw-type anchors 24 embedded in the concrete sidewalls 23 of the channel 14 . [0046] The frame parts 19 , 20 are connected to the connecting frame 22 in such a way that the framework 10 is inclined relative to the vertical line by an acute transport angle 25 when the ground level 15 extends about horizontally. In the exemplary embodiment shown, the transport angle amounts to approximately 15°, but may, in particular, also be larger. In contrast to the embodiment shown, the transport angle 25 does not have to be a fixed angle, but may also be variable, in which case the framework 10 is connected to the connecting frame 24 in a pivoted fashion. [0047] The shaft 21 drives chain wheels 26 that are arranged to both sides of the filter belt 11 and respectively serve for driving a drive chain 28 . The drive chains 28 are composed of chain links 30 , wherein a synopsis of the illustrations in FIGS. 2 and 3 elucidates, in particular, that two respective chain links 30 of the drive chains 28 accommodate a filter element 31 between one another, namely such that the drive chains 28 form the filter belt 11 together with the filter elements 31 . [0048] The filter elements respectively feature a filter basket 40 that consists of a perforated sheet metal material in the present embodiment and features an inflow bottom 33 that is designed convexly toward the flow direction 17 and features front surfaces 34 , 35 that are angled toward its edges in the transport direction and form an abutment edge 36 . The filter baskets 40 feature sidewalls 37 , 38 with a disk-shaped design in order to form a lateral boundary of the inflow bottom 33 and to connect the chain links 30 . [0049] FIGS. 2 and 3 furthermore show that a filter gap 41 is formed between the abutment edges 36 of two adjacent filter elements 31 , wherein a gap seal 42 is arranged in said filter gap. The adjacent abutment edges 36 are arranged parallel and to both sides of the link axis 52 , on which the chain links 30 and therefore the filter elements 31 are pivotally connected to one another by means of chain bolts. [0050] According to FIG. 4 and, in particular, the enlarged illustration of the gap seal 42 in FIG. 5 , the gap seal features a sealing strip 43 that is manufactured of a round material in the exemplary embodiment shown and non-positively connected to a prestressing device 55 . The prestressing device 55 features a tension element 45 that is realized in the form of a tie rod in this case and connected to the sealing strip by means of a connecting end 44 . A pressure spring element 46 that is realized in the form of a dimensionally elastic plastic sleeve in this case is arranged on the tension element 45 and penetrated by the tension element 45 in such a way that the pressure spring element 46 is accommodated between a spring stop 47 that is formed by a nut screwed onto the free end of the tension element 45 in the present embodiment and a supporting stop that is arranged on the tension element 45 in a longitudinally displaceable fashion. The supporting stop 48 is realized in the form of a supporting sheet metal in the present embodiment and supported on supporting edges 54 formed by free ends of the respective front surfaces 35 and 34 . [0051] Due to the tensile force exerted upon the sealing strip 48 by the pressure spring element 46 , the sealing strip 43 is pressed against the front surfaces 34 , 35 of the adjacent filter elements 31 with its peripheral contour 49 , wherein the front surfaces 34 , 35 form a wedge-shaped receptacle for the sealing strip 43 due to their V-shaped arrangement relative to one another and define the narrowest point of the filter gap 41 in the flow direction 17 . [0052] In contrast to FIGS. 2 to 5 that shows two adjacent filter elements 31 in a relative arrangement during the movement along a longitudinal transport section 50 (see FIG. 1 ) of the conveyor belt filter device, FIGS. 6 to 9 show the relative arrangement of two filter elements 31 in the deflection region 51 (see FIG. 1 ) of the conveyor belt filter device. In other respects, FIGS. 6 to 9 show the same elements and components of the conveyor belt filter device, wherein these elements and components in FIGS. 6 to 9 are identified by the same reference symbols as in FIGS. 2 to 5 . [0053] A comparison of FIGS. 4 and 5 that show the relative arrangement of the gap seal 42 in the filter gap 41 during a movement of the filter elements 31 along the longitudinal transport section 50 with FIGS. 8 and 9 that show the relative arrangement of the gap seal 42 in the filter gap 41 in the deflection region 51 elucidates, in particular, that the relative pivoting movement of the filter elements 31 about the link axis 52 (see FIG. 6 ) causes a shift in the position of the sealing strip 43 on the front surfaces 34 , 35 of the adjacent filter elements 31 . However, this comparison also elucidates that the contact of the peripheral contour 49 of the sealing strip 43 with the front surfaces 34 , 35 is still ensured despite the changed relative positioning. The changed arrangement of the front surfaces 34 , 35 relative to one another caused by the deflection merely leads to an increase in the tensile stress acting upon the sealing strip, namely as the result of a compression of the pressure spring element 46 that takes place between the spring stop 47 of the tension element 45 and the supporting stop 48 . [0054] In order to ensure that the tension element 45 is not clamped in the filter gap 41 in the relative arrangement of the front surfaces 34 , 35 illustrated in FIG. 9 , the front surfaces 34 , 35 may be provided with corresponding recesses in the region of the abutment edges 36 . [0055] FIGS. 10 to 12 show another optional embodiment of a gap seal 60 that serves for sealing a filter gap 41 formed between the front surfaces 34 , 35 of adjacent filter elements 31 . In the present embodiment, the gap seal 60 features a sealing strip 43 that corresponds to the sealing strip 43 of the gap seal 42 . In contrast to the gap seal 42 , the gap seal 60 features a prestressing device 65 with a tension element 61 that, according to a synopsis of FIGS. 10 and 12 , consists of a sheet metal strip with a rectangularly designed recess 62 for accommodating the sleeve-shaped pressure spring element 46 . In order to non-positively position the pressure spring element 46 in the recess 62 of the tension element 61 , a supporting stop 63 is provided that consists of a sheet metal strip in the present embodiment and features a correspondingly designed through-slot 64 , through which the tension element 61 extends. [0056] According to FIGS. 10 and 11 that show the relative positioning of the sealing strip 42 of the gap seal 60 between the front surfaces 34 and 35 of the adjacent filter elements 31 during the movement along a longitudinal transport section 50 ( FIG. 10 ) and the aforementioned relative positioning during a movement in the deflection region 51 ( FIG. 11 ), the pressure spring element 46 is supported during a compression on a supporting edge 65 of the recess 62 arranged in the tension element 61 , as well as on the supporting stop 63 that can be longitudinally displaced relative to tension element 61 . [0057] The preceding explanation of the design of the gap seal 60 makes it clear that an installation of the gap seal 60 in a filter gap 41 formed between adjacent filter elements 31 can be realized in a particularly simple fashion because no tool is required and the gap seal 60 can be securely positioned in the filter gap 41 by locking the supporting stop 63 relative to the tension element 61 under prestress by means of a pressure spring element 46 . [0058] In contrast to the exemplary embodiments shown, it is naturally also possible, if so required, to assign several prestressing devices to the sealing strips of the gap seals rather than only one prestressing device.	The invention pertains to a conveyor belt filter device comprising: (a) an endless filter belt of flat, interconnected filter elements that can be respectively pivoted relative to one another about a horizontal link axis; (b) flexible driving means that are respectively provided to both sides of the filter belt and consist of a chain drive with deflection elements and two endless drive chains, on which the filter elements are laterally mounted; and (c) a framework that carries the deflection elements and the filter belt, wherein each filter element is rigidly mounted on a chain link and front surfaces of the filter element respectively feature an abutment edge that extends parallel to the link axes of the chain links, such that the opposite abutment edges define a filter gap formed between two filter elements, and wherein the filter gap is provided with a gap seal.
You are an expert at summarizing long articles. Proceed to summarize the following text: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a hinge damper of an opening/closing device that enables smooth and safe opening/closing of an opening/closing member of a document pressing plate of a copier or an opening/closing member of a toilet seat. [0003] 2. Related Art [0004] Conventionally, in an opening/closing device of a document pressing plate that includes an attachment member that is attached to an apparatus body such as a copier, a support member that can freely rotate and support the document pressing plate while being pivotally attached to the attachment member, and a compressed coil spring that is inserted between the attachment member and the support member while biasing the document pressing plate to the opening direction thereof, there is a technique that prevents the document pressing plate from suddenly falling because the weight of the document pressing plate overcomes the bias of the pressed coil spring and resultingly prevents a hand of the user from being caught between the plate and the apparatus body or the position of the document being moved (for example, refer to Patent Document 1). [0005] However, the above-mentioned conventional technique to prevent the document pressing plate from sudden falling uses an oil damper and therefore has the following problems: 1. As the damper absorbs energy in the loading direction, rigidity is required for the case that receives a piston; 2. Since it is made of metal such as die-cast, the damper is heavy. In addition, since it becomes long in its axial direction, the damper requires space for installation; 3. To put it in a coil spring in a hinge, the spring itself is large-sized; 4. Since the oil viscosity resistance is converted into heat energy, it comes to possess high temperature when used continuously. Moreover, since the oil viscosity resistance depends on the outside temperature, it is unstable. Therefore, there may be cases where the damper does not function well when the opening/closing device is opened and closed in succession; 5. If the document pressing device is closed forcibly, overload is applied to the damper to raise the oil pressure inside thereof, which may lead to a damage; 6. Since the piston rod of the damper is prone to eccentric loading, it must be operated with high accuracy and may easily cause oil leakage and/or breakage of the device; 7. Oil or water around the damper may adhere on the piston rod, causing damage to a packing or malfunctioning; 8. When disposed, it requires an environmental measure due to oil or the like, and; 9. Since the oil depends on the outside temperature, when used in a location that is not kept in room temperature, performance of the damper differs significantly. Patent Reference 1: Japanese Utility Model Publication No. 2589714 [0015] The purpose of the present invention is to provide a hinge damper of an opening/closing device that can solve the above mentioned problems and is light weight, small, stable even when used for a long period of time, and easy to perform maintenance. SUMMARY OF THE INVENTION [0016] A hinge damper of the present invention includes an attachment member to be attached to an apparatus body such as a copier, a support member that can freely rotate and support a open/close member such as a document pressing plate while being pivotally attached to the attachment member, a compressed coil spring that is inserted between the attachment member and the support member while biasing the open/close member toward its opening direction, and an elastic body such as urethane elastomer foam, wherein a rotation axis that is rotated according to the rotation of a rotation member and is pivotally attached to a case to be able to rotate, a gearing that is attached to the rotation axis while having internal teeth, means for transferring the rotation of the open/close member to the gearing, a gear planet that is engaged with the internal teeth of the gearing, rotation control means that regulates the rotation of the gear planet so that its center performs circular locus movement around the rotation center of the gearing, and means that absorb the rotation energy of the gearing are included. In addition, the means that transfers the rotation of the open/close member to the gearing is a sector gear. Moreover, the means that regulates the rotation of the gear planet has an actuation pin that is implanted in the gear planet and a bush that has a hole to which the actuation pin is inserted so that the action of the pin is regulated. Furthermore, the means to absorb the rotation energy of the gearing has a friction tooth formed on the gearing and a plate planet having wave-shape periphery surface on which the friction tooth slides. Still furthermore, the hinge damper is incorporated into the attachment member of the open/close member. [0017] The hinge damper of the present invention has following advantages; it has a large capacity to absorb energy thanks to the structure of a small damper function, is light weight and small, stable when used for a long period of time, and is easy to perform maintenance. Moreover, there is another advantage that as it does not use oil like conventional oil dampers, problems mentioned above can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS [0018] FIG. 1A is a side-view of an opening/closing device of a document pressing plate having a hinge damper of the present invention and 1 B is a view showing its function. [0019] FIG. 2 is an external view of the hinge damper. [0020] FIG. 3 is a perspective view of a hinge damper that is disassembled in a support axis direction. [0021] FIG. 4 is a cross sectional view of the hinge damper. [0022] FIG. 5 is a cross sectional view taken along a line A-A of FIG. 4 . [0023] FIG. 6 is a cross sectional view taken along a line B-B of FIG. 4 . DESCRIPTION OF THE PREFERRED EMBODIMENTS [0024] Hereinafter, an embodiment of a hinge damper of an opening/closing device of the present invention will be described referring to figures. [0025] In FIG. 1 , P is a document pressing plate which is attached to M, a main body of a copier or the like, via an H, which is an opening/closing device. P can open/close freely. The opening/closing device H mainly includes an attachment member 1 which is attached to the main body M, a support arm 3 which is pivotally attached to the attachment member 1 via a hinge axis 2 so as to allow the support arm 3 to freely move in a rotational manner, and a lift arm 5 which is pivotally attached to a tip of the support arm 3 via a support axis 4 so as to allow the lift arm 5 to freely move in a rotational manner. [0026] In the support arm 3 , a first slider 6 and a second slider 7 are installed while enabling them to freely slide in a longitudinal direction. Between the first and second sliders 6 and 7 , a compressed coil spring 8 is inserted. Instead of the compressed coil spring 8 , an urethane elastomer foam may be used. A cam follower 6 a of the first slider 6 is attached to a cam part 9 placed on the attachment member 1 , while a cam follower 7 a of the second slider 7 is attached to a front side plate 5 a of the lift arm 5 . Note that the opening/closing device H of the present invention is not limited to the structure described above and any conventional structure, for example, one in which the support axis 4 and the lift arm 5 are not included and the document pressing plate P is attached and fixed to the support arm 3 , may be used. [0027] In the attachment member 1 which is in the vicinity of the hinge axis 2 , a case 10 of the hinge damper is provided. [0028] FIG. 2 shows external appearance of the case 10 of the hinge damper and the case 10 includes a case body 10 a and a lid 10 b . 11 is an attachment frame for attaching the case 10 to the opening/closing device H. In the case 10 , as shown in FIG. 3 which is an exploded diagram, a hinge damper is installed. [0029] In FIG. 3, 12 is a sector gear, 13 is a small gear, 14 is a support axis, 15 is a first internal tooth gear, 16 is a first gear planet, 17 a is a first eccentric shaft, 17 b is a second eccentric shaft, 18 is a second internal tooth gear, 19 is a second gear planet, 20 is a third internal tooth gear, 21 is a third gear planet, 22 a is a third eccentric shaft, 22 b is a fourth eccentric shaft, 23 is a fourth internal tooth gear, and 24 is a fourth gear planet. [0030] As apparent from FIG. 5 , the sector gear 12 is attached and fixed to the hinge axis 2 of the opening/closing device H and rotates along with the rotation of the hinge axis 2 . On the sector gear 12 , along the rotation angle thereof that is almost equal to the rotation angle of the opening/closing device H, teeth 12 a are formed. [0031] The small gear 13 is attached to freely rotate around the support axis 14 and is engaged with the sector gear 12 . A flange portion 13 a is provided to the small gear 13 in an integrated manner. The flange portion 13 a has a plain part 13 a ′. On the tip of the support axis 14 , a square-headed bolt 14 a is provided and is fitted into a square hole 11 a of the attachment frame 11 to prevent it from rotating. [0032] As apparent from FIG. 5 , the flange portion 13 a of the small gear 13 is fitted into a hole 15 a formed on the first internal tooth gear 15 and a plain part 15 a ′ thereof is attached to the plain part 13 a ′ of the flange portion 13 so that they are rotated in an integrated manner. [0033] As shown in FIG. 6 , teeth 16 a of the first gear planet 16 is engaged with teeth 15 a of the first internal tooth gear 15 and can roll. The first gear planet 16 is attached to the first eccentric shaft 17 a and can freely rotate. The first eccentric shaft 17 a is attached to the support axis 14 and cannot rotate. Therefore, the first gear planet 16 rotates in a condition where it is decentered to the central axis of the support axis 14 . [0034] As apparent from FIG. 4 , the second internal tooth gear 18 is connected to the first gear planet 16 so that they rotate in an integrated manner. The second internal tooth gear 18 is engaged with the second gear planet 19 so that they rotate in an integrated manner. The second gear planet 19 is attached so that it rotates in a condition where it is decentered to the second eccentric shaft 17 b . The first eccentric shaft 17 a and the second eccentric shaft 17 b are located to be symmetric to the central axis of the support axis 14 . [0035] The third internal tooth gear 20 is connected to the second gear planet 19 so that they can rotate in an integrated manner. The third gear planet 21 is engaged with the third internal tooth gear 20 so that they can rotate in an integrated manner. The third gear planet 21 is attached so that it rotates in a condition where it is decentered to the third eccentric shaft 22 a. [0036] The fourth internal tooth gear 23 is connected to the third gear planet 26 so that they can rotate in an integrated manner. The fourth internal tooth gear 23 is engaged with the fourth gear planet 24 so that they can rotate in an integrated manner. The fourth gear planet 24 is attached so that it rotates in a condition where it is decentered to the fourth eccentric shaft 22 b . The third eccentric shaft 22 a and the fourth eccentric shaft 22 b are located to be symmetric to the central axis of the support axis 14 . [0037] Because the hinge damper of the present embodiment is structured as above, when the document pressing plate P is closed as in FIG. 1 (B) to the arrow direction, the sector gear 12 integrated with the hinge axis 2 is rotated counterclockwise, as indicated by an arrow in FIG. 2 , and turns the small gear 13 clockwise. [0038] When the small gear 13 rotates, together with this movement, the first internal tooth gear 15 rotates and the first gear planet 16 that is engaged with the internal tooth gear 15 rotates in the same direction. The number of teeth N of the first internal tooth gear 15 is more than the number of teeth of the first gear planet 16 n (N>n). Therefore, when the first internal tooth gear 15 is rotated 360°, speed of the first gear planet 16 is increased for the N/n times of rotation. [0039] The rotation of the first gear planet 16 also increases the speed of the second gear planet 19 via the second internal tooth gear 18 . Thus, the speed of the third gear planet 21 and the fourth gear planer 24 are increased sequentially. [0040] Due to the engagement friction (resistance) of each internal gear and gear planet, the rotation energy is absorbed. [0041] Means to transfer the rotation of the opening/closing device H is not limited to the above mentioned sector gear or other kind of gear and a power transmission mechanism such as a belt or a link may be used. [0042] The opening/closing device of the hinge damper of the present invention is not limited to the above mentioned document pressing plate of a copier, but is applicable to hinge that opens/closes an open/close member of a scanner, a fax, or a lid of a toilet seat.	A hinge damper is comprised of a rotation axis that is rotated according to the rotation of a rotation member and is pivotally attached to a case to be able to rotate freely, a gearing that is attached to the rotation axis to be able to freely rotate while having an internal tooth, means for transferring the rotation of the open/close member to the gearing, a gear planet that is engaged with the internal tooth of the gearing, rotation control means that regulates the rotation of the gear planet so that its center performs circular locus movement around the rotation center of the gearing, and means that absorbs the rotation energy of the gearing.
You are an expert at summarizing long articles. Proceed to summarize the following text: REFERENCE TO RELATED APPLICATIONS The present application is a continuation application of U.S. patent application Ser. No. 11/732,388, filed Apr. 3, 2007, now U.S. Pat. No. 7,651,294 B2, entitled SOIL STABILIZATION METHOD, and claims the benefit of U.S. Provisional Patent Application No. 60/789,640, filed Apr. 6, 2006, each hereby incorporated in its entirety by this reference. FIELD OF THE INVENTION The present invention relates to reconstructing and paving roads. More specifically, the present invention is method of using a soluble sodium silicate composition to stabilize soil for a road base or sub-base applicable to the construction of new roads and the reconstruction or reinforcement of existing roads. BACKGROUND OF THE INVENTION Construction and maintenance of roads, especially secondary roads, requires a solid, stabilized base and sub-base on which to place the road surface. Preparation for road paving generally includes compaction of the base or sub-base, which may comprise clay, gravel, crushed stone, and the like, either taken from the native materials or transported to the site. Frequently, the base material includes crushed concrete and asphalt from the old road base or surface. Whether the material is primarily reclaimed from an old road surface material, taken from a new or old base on site, or is made from materials transported to the site, maximizing the stability of the material increases the longevity of the road surface and decreases the frequency and cost of repairs. Soils too weak to bear the anticipated load can be stabilized by the addition of materials which impart mechanical strength, such as aggregate, and by the addition of chemical stabilizers, which decrease water absorption and increase the cohesion of the soil matrix by forming a cement-like compound to hold the matrix together. The appropriate type of stabilization and results to be expected depend upon the soil types encountered and methods of application of the stabilizer and construction of the road. A range of soil compositions can serve as good road base material, but high strength, resistance to shear, and resistance to erosion or swelling by water are required. Most native soils require some extent of stabilization to achieve the goals and provide a proper material for road construction. Failure to provide an adequately stabilized base results in frequent and expensive repairs. Various techniques and compounds are known for stabilizing the soil or fill beneath pavement or other construction to provide a stable, high integrity base on which to place the pavement or other construction. Materials commonly used for this purpose include lime and fly-ash mixtures, calcium chloride, sodium silicates, mixtures of molasses and fuel oil, calcium acrylate, lignin sulfonate, and other materials. Chlorides are the most commonly used product for soil stabilization. Calcium chloride assists in the compactive process, making it possible to obtain greater densities and greater strengths with normal compactive efforts. A major limitation of calcium chloride is its narrow application range. If the calcium chloride solution is applied at a less than specific dilution ratio the effectiveness of the compound is diminished, while application at a higher than necessitated dilution ratio causes beading on the application surface and thus prevents treatment of the target soil. Further, the widespread use of large quantities of chlorides has been shown to be environmentally harmful. Finally, chlorides are extremely corrosive on road construction and maintenance equipment. Resins available under various commercial names are used as soil stabilizers and typically comprise lignin sulfonate, which is a by-product of the pulp milling industry. Lignin sulfonate is also referred to as “tree sap” by those skilled in the art of road construction. They provide cohesion to bind soil particles together, but are primarily used when they can be incorporated into the surface gravel. Additives used for roadbed stabilization are disclosed by U.S. Pat. No. 4,106,296 (epoxy resins), U.S. Pat. No. 4,373,958 (lime kiln dust), U.S. Pat. No. 5,577,338 (fly ash), U.S. Pat. No. 5,820,302 (silicate and cement), and U.S. Pat. No. 6,689,204 (potassium formate and cationic polymer), all of which are incorporated herein by reference. U.S. Pat. No. 7,070,709, incorporated herein by reference, discloses various prior art compositions used for soil stabilization. Those products, however, have numerous disadvantages such as poor longevity, high cost, and environmental toxicity. The trade-offs are either accepting the environmental issues that come with products of longer useful life; dealing with a shorter lifespan for an environmentally friendly product; or paying significantly more for environmentally safe products with a favorable useful life. A more acceptable method of roadbed stabilization is needed. It is an object of this invention to provide an improved composition and method of using the improved composition for soil stabilization that is both economical and environmentally sound. SUMMARY OF THE INVENTION The present invention is directed to a method of using a composition to provide solid, stabilized, and extremely hard bases and sub-bases for road construction. The composition is generally comprised of a soluble sodium silicate which, applied at the disclosed application rate, improves the load bearing capacity for a given roadway at a fraction of the cost of existing materials. The method of the invention addresses the application of the disclosed composition to maximize stabilization of roadbeds. The present invention addresses drawbacks experienced with the prior art because it provides an effective road stabilizer that is both economical and environmentally friendly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention. The descriptions eliminate, for purposes of clarity, elements found in typical soil stabilizers and detailed explanations of procedures used in road construction. Those of ordinary skill in the art will recognize that other elements of both the composition and method may be desirable or necessary to implement the present invention. Because such elements are well known in the art and do not facilitate a clearer understanding of present invention, a description of such elements may not be provided herein. The stabilizer of the present invention comprises a non-toxic, water soluble chemical composition used as a material stabilizer for road bases. The disclosed stabilizer generally comprises a soluble sodium silicate in a water base, otherwise known as “waterglass.” The preferred embodiment of the stabilizer contemplates an aqueous solution consisting of 28-30 percent silicon dioxide by weight and 8.5-9.5 percent sodium oxide by weight with an overall specific gravity ranging from 1.37 to 1.42 and an average viscosity of 150 at 20° C. The average weight ratio of silicon dioxide to sodium oxide for the stabilizer should be between 3.1 and 3.4. A commercial version of the stabilizer is available from INEOS Silicas Americas located in Joliet, Ill. under the trade name Crystal® 78. Application of the stabilizer of the present invention is accomplished by the use of conventional spray equipment known in the art of road construction and maintenance. It may be gravity fed or pumped through hoses, spray nozzles, or fixed sprayers to uniformly apply the compound to the material to be treated. Motor-graders, asphalt grinders, mixers, pug mills, compactors, rollers, and other conventional road construction equipment may be utilized to blend, set grade, and compact the stabilized base. A preferred embodiment of the present invention includes the application of the stabilizer at three steps of the road bed construction at specific application rates. In the preferred embodiment, it is recommended that the road bed be laid in sections of ¼ to ½ mile in length. Once the road bed has been leveled and the bed construction material has been windrowed along the road, the road bed is prepared by applying stabilizer to the road bed at a rate of 20-25 gallons per mile of 24′-30′ width road surface. The amount of water in which the stabilizer is diluted will depend upon the type of applicator used, size of the water truck, and the weather conditions (temperature, humidity, wind). The typical recommended dilution is about 55 gallons of stabilizer per 5,000 gallons of clean water. After the initial application of the stabilizer, the road bed should be compacted by any of the various methods known in the art of road construction. The second step of the preferred embodiment involves applying material from the windrow to the road bed in one- to two-inch lifts. As the grader is laying material from the windrow across the road, the stabilizer is applied to the lift and then mixed into the material placed upon the road bed. The amount of stabilizer applied per lift will depend upon the number of lifts to be used in the road bed construction. A total of 220 gallons of stabilizer should be used for each mile of 24′-30′ width of road surface assuming a total bed thickness of three to four inches. The amount of water used for the application of the 220 gallons of stabilizer per mile will depend upon the type of applicator used, size of the water truck, and the weather conditions. Each lift of mixed material and stabilizer should be well mixed and compacted by any of the methods known in the art prior to application of the next lift. This process is repeated until all lifts have been applied (windrow has been completely used) and well compacted. The finish grade and slope of the bed should then be prepared. The third step of the preferred embodiment is finishing off the road bed surface with additional stabilizer. The stabilizer is applied to the finished bed at a rate of 25-30 gallons per mile of 24′-30′ width road surface. Compaction of the road surface should continue until the surface is dry. As with the previous steps, the amount of water used to dilute the 25-30 gallons of stabilizer will depend upon the type of applicator used, the size of the water truck, and the weather conditions. The preferred embodiment also contemplates keeping the working surfaces wet while compacting. The appropriate amount of moisture for working road compaction is well known by those in the art of road construction. It is recommended that compactors constantly work the road to maximize the hardening provided by the stabilizer. Roadways may be further enhanced by the application of a sealant to protect the new road bed from the elements. The preferred embodiment contemplates using a seal coating process such as the application of a bituminous chip seal. As road widths vary, the present invention contemplates using the following total stabilizer amounts for all three steps per mile of road at the ratios described herein: Road Bed Surface Width (Feet) Amount of Stabilizer (Gallons) 24-30 275 31-37 330 38-44 385 45-51 440 While the present invention may be used for a wide variety of aggregate mixtures comprising clay material, caliche soils, and sandy loam with low sand content, it is recommended that the soil used in constructing the road bed consist of a good binding material with aggregate large enough to provide a driving surface. Examples of aggregate gradation that provide exceptional results are provided below: Example A Example B Sieve Size % Passing Sieve Size % Passing 1″ 100 1″ 100 ¾″ 100 ¾″ 100 ⅜″ 65-95 ⅜″ 50-85 #4 40-85 #4 35-80 #10 20-70 #10 20-70 #40 10-45 #40 10-40 #200 10-15 #200 10-15 Example C Example D Sieve Size % Passing Sieve Size % Passing 1″ 100 ¾″ 100 ¾″ 95-100 #4 38-75 ⅜″ 65-95 #8 22-62 #4 40-75 #30 12-37 #10 25-70 #200 8-15 #40 10-45 #200 10-15 The material passing through the #200 sieve should be binding-type material such as clay and not silt. The present invention may be embodied in other specific forms without departing from the spirit of any of the essential attributes thereof; therefore, the illustrated embodiment should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.	A composition and method of use of said composition for soil stabilization is disclosed. The composition comprises a solution of soluble sodium silicate applied at the disclosed application rate to improve the load bearing capacity for a roadway. The method of the invention addresses the application of the disclosed composition to maximize stabilization of road beds.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATIONS This application is a non-provisional application which claims benefit under 35 USC §119(e) to U.S. Provisional Application Ser. No. 61/156,266 filed Feb. 27, 2009, entitled “Recovery of Hydrocarbons From Oil Shale Deposits,” which is incorporated herein in its entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT None FIELD OF THE INVENTION This invention relates to the recovery of hydrocarbons from in ground oil shale reserves. BACKGROUND OF THE INVENTION The United States has an almost unimaginable volume of hydrocarbons locked up in huge reserves of oil shale. However, the current technology for recovering oil from oil shale has been a substantially expensive process that is only economically viable when crude oil prices are high. Shale does not have the energy density of coal with more than about 85% being rock. While mining the shale is discouraged by the cost, another technique for liberating the hydrocarbons has been to create an underground retort or reaction vessel and heating shale to a temperature that cracks the hydrocarbon and releases a shale oil. The process of creating the retort begins by defining the area that one wants to work with. Keep in mind that the shale deposits can extend horizontally for hundreds of miles. So, for instance, an in-situ retort may be defined as perhaps 200 feet by 400 feet and by the thickness of the oil shale deposit which can vary between 200 feet and up to 2,000 feet thick. Within the retort area, about twenty percent of the shale deposit is removed or mined out and the remaining portion has boreholes drilled in a pattern for an explosive to convert the solid shale formation into rubble. This rubbilizing process opens up the shale so that it can be heated by the circulation of hot gases and a drain is installed at the base of the retort to collect the shale oil. The heat of the process also creates gases including hydrocarbons which are collected through a separate recovery device. Into the top of the retort, air is injected and a combustion process is ignited. The retort includes an overburden so the top of the retort is not open to the atmosphere. The air injection provides enough oxygen for combustion, but does not burn all of the hydrocarbons. Indeed, the remaining gases in the retort are oxygen depleted so the hydrocarbons are thermally cracked and vaporized. Some of this product condenses into hydrocarbon liquids when cooled in lower regions of the retort. It then drains by gravity to recovery equipment at the bottom of the retort. This process may burn for many months, but the temperature control is quite poor and the retort can easily reach very high temperatures up to and including 1,700° F. This process was developed before concerns were substantially raised about the liberation of carbon dioxide and other greenhouse gases. The rock which holds the kerogen is substantially comprised of metal carbonates such as calcium carbonate, aluminum carbonate. If these rock materials are heated in excess of 1,100 F, they decompose into metal oxides and carbon dioxide. Many tons of carbon dioxide could easily be released by processing of one retort of the size described and the carbon would not be from the small amount of hydrocarbon present. Clearly, technology for economically recovering oil shale would be very helpful to the United States in terms of American energy independence, but recovery of the oil shale must be accomplished in an environmentally safe and sensitive manner for the technology to be practically applied. SUMMARY OF THE INVENTION The present invention more particularly comprises a process for recovering hydrocarbons from oil shale where the process comprises a first step of identifying a quantity of oil shale in the ground. A portion of the oil shale is removed to create void space in the oil shale formation in the ground and the remaining oil shale is rubblized to enable gases to flow through the identified quantity of oil shale. A gas delivery line is installed near an upper portion of the identified quantity of oil shale and gas and liquid recovery lines are installed near the lower portion of the identified quantity of oil shale. A substantially oxygen-free gas is injected through the gas delivery line that is heated to a temperature that will increase the temperature of the identified quantity of oil shale and cause thermal cracking of kerogen in the identified quantity of oil shale where gas and liquid hydrocarbons are recovered from the identified quantity of oil shale via the gas and liquid recovery lines. The present invention may also be characterized as a process for recovering hydrocarbons from oil shale where the process comprises a first step of identifying a quantity of oil shale in the ground. A portion of the oil shale is removed to create void space the upper portion of the quantity of oil shale in the ground where the remaining oil shale in the ground is rubblized by detonating explosives to enable gases to flow through the identified quantity of oil shale. A gas delivery line is installed to provide gas into the remaining void space at the upper portion of the identified quantity of oil shale in the ground and gas and liquid recovery lines are installed near the lower portion of the identified quantity of oil shale. A substantially oxygen-free gas is injected through the gas delivery line that is heated to a temperature that will increase the temperature of the identified quantity of oil shale and cause thermal cracking of kerogen in the identified quantity of oil shale. Gas and liquid hydrocarbons are recovered from the identified quantity of oil shale via the gas and liquid recovery lines altering the oil shale to form spent shale. After the hydrocarbons are essentially recovered from the spent shale, burning char in the spent shale by injecting a combination of air and oxygen depleted gases into the spent shale to control the burn rate of the char. The temperature of the identified volume of oil shale and the temperature of the gases returning from the identified volume of oil shale through the gas line are monitored and the amount of air being added to the recycled gases is adjusted to maintain the temperature of the spent shale to be within a predetermined temperature range. BRIEF DESCRIPTION OF THE DRAWINGS The invention, together with further advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which: FIG. 1 is a fragmentary cross sectional view of an oil shale retort with diagrammatic components at the surface used for the production of hydrocarbons from oil shale in-situ in an earthen formation; FIG. 2 is a flow diagram of a system for recovering shale oil from an oil shale retort of the present invention; and FIG. 3 is a flow diagram of another embodiment of the system for recovering shale oil from an oil shale retort of the present invention. DETAILED DESCRIPTION OF THE INVENTION Turning now to the preferred arrangement for the present invention, reference is made to the drawings to enable a more clear understanding of the invention. However, it is to be understood that the inventive features and concept may be manifested in other arrangements and that the scope of the invention is not limited to the embodiments described or illustrated. The scope of the invention is intended only to be limited by the scope of the claims that follow. Turning to FIG. 1 , an oil shale retort is generally indicated by the arrow 10 . The retort 10 has been formed by removing a portion of the oil shale and then rubbilizing oil shale in a formation within a defined volume. The defined volume forms an underground retort or an in-situ retort and the rubbilizing is accomplished by drilling a pattern of holes into the formation and subjecting the formation to explosions which break up the formation. Preferably about 20% of the shale has been removed at various elevations within the retort to provide void space for the rubblized oil shale to expand into and to provide some remaining void space 11 below the overburden of earth extending to the surface. A gas delivery line 15 carries gases that are substantially free of oxygen from the surface to the void space 11 . A blower 20 and process heater 25 work in conjunction to provide hot gases into gas delivery line 15 to begin heating the oil shale at the top of the retort 10 . A gas recovery line 30 is similarly arranged to recover gases from the bottom of the retort 10 and carry the gases back to the blower 20 . Within or adjacent to the gas recovery line 30 is a liquids recovery line 35 to carry liquids that have separated from the gases at the base of gas recovery line 30 . A pump that is not shown or other suitable technology is used for lifting the liquids to a storage tank 40 at the surface. At locations distributed within the retort both horizontally and vertically are temperature sensors 45 which are installed to provide retort temperature readings to a control center 50 at the surface. Hot gases, preferably gases without sufficient oxygen content to support downhole combustion, are directed into the retort 10 to thermally crack the kerogen in the oil shale. The cracked kerogen forms various hydrocarbon liquids and gases that are driven deeper into the retort by the combination of gravity and the flow of the gases toward the gas recovery line 30 . However, it takes a considerable volume of hot gases to heat the oil shale in the vicinity of the void space 11 sufficiently to crack the kerogen. The temperature at which kerogen cracks is between 700° F. and 950° F. The blower 20 directs a substantially oxygen free gas to a process heater 25 which may burn natural gas or propane or the like to provide heat for the gases used in circulation in the retort 10 . Later, when kerogen begins cracking and hydrocarbons are recovered in gas recovery line 30 , the process heater 25 may be arranged to burn hydrocarbon containing gases that are derived from the oil shale. As should be recognized, the process for recovering the hydrocarbons from the oil shale begins with a lot of preparation of the retort where an amount of oil shale is removed from the formation to form the void space, the gas inlet and recovery lines are installed along with the liquid recovery line and the temperature sensors. With all this pre-work completed, the recovery of hydrocarbons may begin. Turning now to FIG. 2 , the installation at the surface may be more easily understood where blower 20 directs the gases to three potential locations. The first is through the process heater 25 and on through gas delivery line 15 and into the retort 10 as has already been described. Once the upper portion of the retort 10 is heated to sufficiently crack the kerogen and sufficient heat has accumulated in the retort, some or all of the gases from the blower 20 are bypassed around process heater 25 via line 26 . After raw product gases begin to emerge from the retort some of the gases will be carried via line 27 for further processing. One option for the product gases is for use in process heater 25 to heat the retort 10 . While retort 10 is in the hydrocarbon recovery mode, a second retort 10 A may be prepared for a similar hydrocarbon recovery process. Start up of the gas circulation is accomplished initially by natural gas or other suitable gas being delivered via inlet 21 so that oxygen-free or substantially oxygen-free gas enters the retort and all the gas recirculating through the retort will be substantially oxygen-free prior to heating of the retort 10 . When heating of the retort begins, the lower portions of the retort will cool the gases such that liquids will condense and separate. A separator 55 is shown in FIG. 2 which will be configured or situated near the bottom of the retort 10 with pump 60 situated to push liquids up through liquid recovery line 35 . As the upper portion of the retort 10 heats up, cool gases will be recovered for an extended period of time, including after kerogen is being cracked at upper portions and the hydrocarbons are being recovered at the lower portions of the retort 10 . Eventually, heated gases will be recovered in gas recovery line 30 . At the time hot gases will begin being recovered, a substantial amount of the gas being provided to the retort from blower 20 will bypass process heater 25 as additional heat will not be necessary to continue to accomplish kerogen cracking. The hot gases then may be used to begin heating second retort 10 A. Accordingly, valve 31 , which has been closed until this time is opened and allow hot gases from the bottom of retort 10 to enter second retort 10 A through second gas delivery line 15 A. Second retort 10 A will be similar to retort 10 having second gas inlet 15 A and gas and liquid recovery lines 30 A and 35 A, respectively. Eventually, a third, fourth and further retorts will be subjected to the heating and heat recovery process described here. Hydrocarbon liquids will almost certainly require further treatment and may be transported to a refinery. As noted above, the recovered hydrocarbon gases may be used as fuel at the site for heating a retort, and also for processing of recovered materials. Gased produced at the retort and from subsequent processing of shale oil will include ammonia due to the high nitrogen content of the oil shale. Ammonia has commercial value and may be separated and collected for transport to market. As the retort heats up and the kerogen cracks and flows to the bottom of the retort, the oil shale retains char that comprises mostly carbon that is solid and adhering to the non-hydrocarbon bearing rock. It is not desirable to recover the char, but rather to use the char as a fuel for producing steam. The oil shale at this point may be described as “spent shale”, but there is still energy that may be recovered and used for continued steam generation as required for other plant energy needs. Turning now to FIG. 3 , retort 10 is set up for char burning where blower 70 is arranged to blow gases down through gas delivery line 15 . Blower 70 may be the original blower 20 used for hydrocarbon recovery and may be a different blower which is subject to operator selection. It should be understood that char burning is a considerably different step from hydrocarbon recovery. Separating these functions maximizes hydrocarbon recovery and avoids losing hydrocarbons to combustion during char burning. If retort 10 has cooled substantially since the hydrocarbon recovery process was concluded, the gases being directed into the retort are heated by process heater 80 and a controlled amount of air is added to the inlet gases from air blower 75 . With oxygen in the air, the char is heated to its auto-ignition temperature until the char lights off. Process heater 80 is shut down and again the temperature of the retort is closely monitored to maintain the temperature below the temperature that the metal carbonates will decompose. Control system 50 , shown in FIG. 1 , regulates the amount of air in the inlet gases where excess gases are vented via line 76 . Hot gases from the retort 10 are carried back to the surface via gas recovery line 30 and are directed to a waste heat boiler 85 where boiler feed water is heated to produce steam that may be used to make electricity with a steam turbine or other known technology. Electricity is certainly needed by the hydrocarbon recovery system for powering the blowers and other equipment. Steam may also be used as a heat source for various processing systems for recovering hydrocarbons or other valuable products. In a manner similar to the sequential hydrocarbon recovery operations on the retorts, the heat from a char burning retort may be used to light off a next retort rather than having to rely on process heater 80 . The amount of gases vented via line 76 is equalized with the air entering via the air blower 75 so that the total volume of the circulated gases is maintained. Based on the temperature of the retort as measured by the temperature sensors and the temperature of the gases coming out of the retort and the amount of carbon dioxide in the gases being recovered through the recovery line, the air content is adjusted to maintain the retort temperature below temperatures that would cause decomposition of carbonate materials into carbon dioxide. Once the char is ignited, its burn rate is controlled to provide enough heat to continue to burn the char and produce steam in the boiler that may drive steam turbines for electric generation and provide process heat for other processes undertaken at the surface location or nearby areas. While it might take months for the retort to begin producing useful heat at the retort outlet after the char is ignited, it is expected that successive retorts may provide heat and electricity for many, many years. Moreover, the process heat from the first retort will be used to heat or preheat a second and successive retorts. Since the reserves in oil shale amount to thousands of square miles, it is quite conceivable to be able to produce hydrocarbons and heat and electric energy for a century or two centuries and realistically much further into the future than that. Finally, the scope of protection for this invention is not limited by the description set out above, but is only limited by the claims which follow. That scope of the invention is intended to include all equivalents of the subject matter of the claims. Each and every claim is incorporated into the specification as an embodiment of the present invention. Thus, the claims are part of the description and are a further description and are in addition to the preferred embodiments of the present invention. The discussion of any reference is not an admission that it is prior art to the present invention, especially any reference that may have a publication date after the priority date of this application.	This invention relates to recovering hydrocarbons from oil shale preferably in-situ where the temperature of the oil shale deposit is controlled to maximize recovery of hydrocarbons and minimize decomposition of carbonate minerals into carbon dioxide that might be released into the atmosphere. The process includes generating heat from hydrocarbon gases recovered from the oil shale and then later performing a controlled burn of the char that is left in the spent shale after the kerogens have been thermally cracked and the most of the recoverable hydrocarbons have been recovered. The burning of the char is also controlled based on the temperature of the oil shale in-situ, the temperature of the gases returning to the surface from the oil shale and the carbon dioxide in the gases returning to the surface.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATIONS This application is related to the following applications, all of which have been filed contemporaneously herewith. (1) U.S. application Ser. No. 927,389 entitled "Method and Apparatus for Sealing the Juncture Between a Vertical Well and One or More Horizontal Wells using Deformable Sealing Means" invented by Douglas J. Murray and F. T. Tilton; (2) U.S. application Ser. No. 926,893 entitled "Method and Apparatus for Sealing the Juncture Between a Vertical Well and One or More Horizontal Wells Using Mandrel Means" invented by R. Curington, L. Cameron White and Daniel S. Bangert; (3) U.S. application Ser. No. 927,567 entitled "Method and Apparatus for Locating and Re-Entering One or More Horizontal Wells Using Whipstocks With Sealable Bores" invented by Mark W. Brockman, L. Cameron White, Jeffrey D. Cockrell and Douglas J. Murray; (4) U.S. application Ser. No. 926,452 entitled "Method and Apparatus for Locating and Re-Entering One or More Horizontal Wells Using Mandrel Means" invented by Daniel S. Bangert, Alfred R. Curington and L. Cameron White; (5) U.S. application Ser. No. 926,451 entitled "Method and Apparatus for Isolating One Horizontal Production Zone from Another Horizontal Production Zone in a Multilateral Well" invented by Robert J. McNair, Mark W. Brockman, L. Cameron White, Jeffrey D. Cockrell, Alfred R. Curington and Daniel S. Bangert. BACKGROUND OF THE INVENTION This invention relates generally to the completion of lateral wellbores. More particularly, this invention relates to new and improved methods and devices for completion of a branch wellbore extending laterally from a primary well which may be vertical, substantially vertical, inclined or even horizontal. This invention finds particular utility in the completion of multilateral wells, that is, downhole well environments where a plurality of discrete, spaced lateral wells extend from a common vertical wellbore. Horizontal well drilling and production have been increasingly important to the oil industry in recent years. While horizontal wells have been known for many years, only relatively recently have such wells been determined to be a cost effective alternative (or at least companion) to conventional vertical well drilling. Although drilling a horizontal well costs substantially more than its vertical counterpart, a horizontal well frequently improves production by a factor of five, ten, or even twenty in naturally fractured reservoirs. Generally, projected productivity from a horizontal well must triple that of a vertical hole for horizontal drilling to be economical. This increased production minimizes the number of platforms, cutting investment and operational costs. Horizontal drilling makes reservoirs in urban areas, permafrost zones and deep offshore waters more accessible. Other applications for horizontal wells include periphery wells, thin reservoirs that would require too many vertical wells, and reservoirs with coning problems in which a horizontal well could be optimally distanced from the fluid contact. Horizontal wells are typically classified into four categories depending on the turning radius: 1. An ultra short turning radius is 1-2 feet; build angle is 45-60 degrees per foot. 2. A short turning radius is 20-100 feet; build angle is 2-5 degrees per foot. 3. A medium turning radius is 300-1,000 feet; build angle is 6-20 degrees per 100 feet. 4. A long turning radius is 1,000-3,000 feet; build angle is 2-6 degrees per 100 feet. Also, some horizontal wells contain additional wells extending laterally from the primary vertical wells. These additional lateral wells are sometimes referred to as drainholes and vertical wells containing more than one lateral well are referred to as multilateral wells. Multilateral wells are becoming increasingly important, both from the standpoint of new drilling operations and from the increasingly important standpoint of reworking existing wellbores including remedial and stimulation work. As a result of the foregoing increased dependence on and importance of horizontal wells, horizontal well completion, and particularly multilateral well completion have been important concerns and have provided (and continue to provide) a host of difficult problems to overcome. Lateral completion, particularly at the juncture between the vertical and lateral wellbore is extremely important in order to avoid collapse of the well in unconsolidated or weakly consolidated formations. Thus, open hole completions are limited to competent rock formations; and even then open hole completion are inadequate since there is no control or ability to re-access (or re-enter the lateral) or to isolate production zones within the well. Coupled with this need to complete lateral wells is the growing desire to maintain the size of the wellbore in the lateral well as close as possible to the size of the primary vertical wellbore for ease of drilling and completion. Conventionally, horizontal wells have been completed using either slotted liner completion, external casing packers (ECP's) or cementing techniques. The primary purpose of inserting a slotted liner in a horizontal well is to guard against hole collapse. Additionally, a liner provides a convenient path to insert various tools such as coiled tubing in a horizontal well. Three types of liners have been used namely (1) perforated liners, where holes are drilled in the liner, (2) slotted liners, where slots of various width and depth are milled along the line length, and (3) prepacked liners. Slotted liners provide limited sand control through selection of hole sizes and slot width sizes. However, these liners are susceptible to plugging. In unconsolidated formations, wire wrapped slotted liners have been used to control sand production. Gravel packing may also be used for sand control in a horizontal well. The main disadvantage of a slotted liner is that effective well stimulation can be difficult because of the open annular space between the liner and the well. Similarly, selective production (e.g., zone isolation) is difficult. Another option is a liner with partial isolations. External casing packers (ECPs) have been installed outside the slotted liner to divide a long horizontal well bore into several small sections (FIG. 1). This method provides limited zone isolation, which can be used for stimulation or production control along the well length. However, ECP's are also associated with certain drawbacks and deficiencies. For example, normal horizontal wells are not truly horizontal over their entire length, rather they have many bends and curves. In a hole with several bends it may be difficult to insert a liner with several external casing packers. Finally, it is possible to cement and perforate medium and long radius wells as shown, for example, in U.S. Pat. No. 4,436,165. While sealing the juncture between a vertical and lateral well is of importance in both horizontal and multilateral wells, re-entry and zone isolation is of particular importance and pose particularly difficult problems in multilateral wells completions. Re-entering lateral wells is necessary to perform completion work, additional drilling and/or remedial and stimulation work. Isolating a lateral well from other lateral branches is necessary to prevent migration of fluids and to comply with completion practices and regulations regarding the separate production of different production zones. Zonal isolation may also be needed if the borehole drifts in and out of the target reservoir because of insufficient geological knowledge or poor directional control; and because of pressure differentials in vertically displaced strata as will be discussed below. When horizontal boreholes are drilled in naturally fractured reservoirs, zonal isolation is being seen as desirable. Initial pressure in naturally fractured formations may vary from one fracture to the next, as may the hydrocarbon gravity and likelihood of coning. Allowing them to produce together permits crossflow between fractures and a single fracture with early water breakthrough, which jeopardizes the entire well's production. As mentioned above, initially horizontal wells were completed with uncemented slotted liner unless the formation was strong enough for an open hole completion. Both methods make it difficult to determine producing zones and, if problems develop, practically impossible to selectively treat the right zone. Today, zonal isolation is achieved using either external casing packers on slotted or perforated liners or by conventional cementing and perforating. The problem of lateral wellbore (and particularly multilateral wellbore) completion has been recognized for many years as reflected in the patent literature. For example, U.S. Pat. No. 4,807,704 discloses a system for completing multiple lateral wellbores using a dual packer and a deflective guide member. U.S. Pat. No. 2,797,893 discloses a method for completing lateral wells using a flexible liner and deflecting tool. U.S. Pat. No. 2,397,070 similarly describes lateral wellbore completion using flexible casing together with a closure shield for closing off the lateral. In U.S. Pat. No. 2,858,107, a removable whipstock assembly provides a means for locating (e.g., re-entry) a lateral subsequent to completion thereof. U.S. Pat. No. 3,330,349 discloses a mandrel for guiding and completing multiple horizontal wells. U.S. Pat. Nos. 4,396,075; 4,415,205; 4,444,276 and 4,573,541 all relate generally to methods and devices for multilateral completions using a template or tube guide head. Other patents of general interest in the field of horizontal well completion include U.S. Pat. Nos. 2,452,920 and 4,402,551. Notwithstanding the above-described attempts at obtaining cost effective and workable lateral well completions, there continues to be a need for new and improved methods and devices for providing such completions, particularly sealing between the juncture of vertical and lateral wells, the ability to re-enter lateral wells (particularly in multilateral systems) and achieving zone isolation between respective lateral wells in a multilateral well system. SUMMARY OF THE INVENTION The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the several methods and devices of the present invention for completion of lateral wells and more particularly the completion of multilateral wells. In accordance with the present invention, a plurality of methods and devices are provided for solving important and serious problems posed by lateral (and especially multilateral) completion including: 1. Methods and devices for sealing the junction between a vertical and lateral well. 2. Methods and devices for re-entering selected lateral wells to perform completions work, additional drilling, or remedial and stimulation work. 3. Methods and devices for isolating a lateral well from other lateral branches in a multilateral well so as to prevent migration of fluids and to comply with good completion practices and regulations regarding the separate production of different production zones. In accordance with the several methods of the present invention relating to juncture sealing, a first set of embodiments are disclosed wherein deformable means are utilized to selectively seal the juncture between the vertical and lateral wells. Such deformable means may comprise (1) an inflatable mold which utilizes a hardenable liquid (e.g., epoxy or cementious slurry) to form the seal; (2) expandable memory metal devices; and (3) swaging devices for plastically deforming a sealing material. In a second set of embodiments relating to juncture sealing in single or multilateral wells, several methods are disclosed for improved juncture sealing including novel techniques for establishing pressure tight seals between a liner in the lateral wellbore and a liner in the vertical wellbore. These methods generally relate to the installation of a liner to a location between the vertical and lateral wellbores such that the vertical wellbore is blocked. Thereafter, at least a portion of the liner is removed to reopen the blocked vertical wellbore. In a third set of embodiments for juncture sealing, several methods are disclosed which utilize a novel guide or mandrel which includes side pockets for directing liners into a lateral wellbore. Other methods include the use of extendable tubing and deflector devices which aid in the sealing process. In a fourth set of embodiments, various methods and devices are provided for assisting in the location and re-entry of lateral wells. Such re-entry devices include permanent or retrievable deflector (e.g., whipstock) devices having removable sealing means disposed in a bore provided in the deflector devices. Another method includes the use of inflatable packers. In a fifth set of embodiments, additional methods and devices are described for assisting in the location and re-entry of lateral wells using a guide or mandrel structure. Preferably, the re-entry methods of this invention permit the bore size of the lateral wells to be maximized. In a sixth set of embodiments, various methods and devices are provided for fluid isolation of a lateral well from other lateral wells and for separate production from a lateral well without commingling the production fluids. These methods include the aforementioned use of a side pocket mandrel, whipstocks with sealable bores and valving techniques wherein valves are located at the surface or downhole at the junction of a particular lateral. It will be appreciated that many of the methods and devices described herein provide single lateral and multilateral completion techniques which simultaneously solve a plurality of important problems now facing the field of oil well completion and production. For example, the side pocket mandrel device simultaneously provides pressure tight sealing of the junction between a vertical and lateral well, provides a technique for easy re-entry of selected lateral wells and permits zone isolation between multilateral wellbores. The above-discussed and other features and advantages of the present invention will be appreciated to those skilled in the art from the following detailed description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings, wherein like elements are numbered alike in the several FIGURES: FIGS. 1A-1B are sequential cross-sectional elevation views depicting a method for sealing a juncture between a vertical and lateral wellbore using deformable sealing means comprising an inflatable mold; FIG. 2A is a cross-sectional elevation view of a deformable dual bore assembly for sealing a juncture between vertical and lateral wellbores; FIG. 2B is a cross-sectional elevation view along the lines 2B--2B; FIG. 2C is a cross-sectional elevation view, similar to FIG. 2B, but subsequent to deformation of the dual bore assembly; FIG. 2D is a cross-sectional elevation view of the dual bore assembly of FIG. 2A after installation at the juncture of a lateral wellbore; FIGS. 3A-C are sequential cross-sectional elevation views depicting a method for sealing a juncture between vertical and lateral wellbores using deformable flanged conduits; FIGS. 4A-D are sequential cross-sectional views depicting a method for multilateral completion using a ported whipstock device which allows for sealing the juncture between vertical and lateral wells, re-entering of multilaterals and zone isolation; FIGS. 5A-I are sequential cross-sectional elevation views depicting a method for multilateral completion using a whipstock/packer assembly for cementing in a liner and then selectively milling to create the sealing of the juncture between vertical and lateral wells and re-entering of multilaterals; FIGS. 6A-C are sequential cross-sectional elevation views depicting a method for multilateral completion using a novel side pocket mandrel for providing sealing of the juncture between vertical and lateral wells, re-entering of multilaterals and zone isolation for new well completion; FIGS. 7A-D are sequential cross-sectional elevation views depicting a method similar to that of FIGS. 6A-C for completion of existing wells; FIG. 8A is a cross-sectional elevation view of a multilateral completion method using a mandrel of the type shown in FIGS. 6A-D for providing sealing junctions, ease of re-entry and zone isolation; FIG. 8B is an enlarged cross-sectional view of a portion of FIG. 8A; FIG. 9A-C are sequential cross-sectional elevation views of a multilateral completion method utilizing a mandrel fitted with extendable tubing for providing sealed junctions, ease of re-entry and zone isolation; FIGS. 10A-B are sequential cross-sectional elevation views of a multilateral completion method similar to the method of FIGS. 9A-C, but utilizing a dual packer for improved zone isolation; FIG. 11A-D are sequential cross-sectional elevation views of a multilateral completion head packer assembly for providing sealed junctions, ease of re-entry and zone isolation; FIG. 11E is a perspective view of the dual completion head used in the method of FIGS. 11A-D; FIG. 12 is a cross-sectional elevation view of a multilateral completion method utilizing an inflatable bridge plug with whipstock anchor for re-entry into a selective lateral wellbore; FIG. 13A-B are cross-sectional elevation views of a production whipstock with retrievable sealing bore with the sealing bore inserted in FIG. 13A and retrieved in FIG. 13B; FIG. 13C is a cross-sectional elevation view of a completion method utilizing the production whipstock of FIGS. 13A-B; FIGS. 14A-K are cross-sectional elevation views of a multilateral completion method utilizing the production whipstock of FIGS. 13A-B providing selective re-entry in multilateral wellbores and zone isolation; FIGS. 15A-D are elevation views partly in cross-section depicting an orientation device for the production whipstock of FIGS. 13A-B; FIGS. 16A-D are sequential cross-sectional views showing in detail the diverter mandrel used in the method of FIGS. 14A-K; and FIG. 16D is a cross-sectional elevation view along the line 16D--16D of FIG. 16B. DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance with the present invention, various embodiments of methods and devices for completing lateral, branch or horizontal wells which extend from a single primary wellbore, and more particularly for completing multiple wells extending from a single generally vertical wellbore (multilaterals) are described. It will be appreciated that although the terms primary, vertical, deviated, horizontal, branch and lateral are used herein for convenience, those skilled in the art will recognize that the devices and methods with various embodiments of the present invention may be employed with respect to wells which extend in directions other than generally vertical or horizontal. For example, the primary wellbore may be vertical, inclined or even horizontal. Therefore, in general, the substantially vertical well will sometimes be referred to as the primary well and the wellbores which extend laterally or generally laterally from the primary wellbore may be referred to as the branch wellbores. Referring now to FIGS. 1A and B, a method and apparatus is presented for sealing the juncture between a vertical well and one or more lateral wells using a deformable device which preferably comprises an inflatable mold. In accordance with this method, a primary or vertical well 10 is initially drilled. Next, in a conventional manner, a well casing 12 is cemented in place using cement 14. Thereafter, the lower most lateral well 16 is drilled and is completed in a known manner using a liner 18 which attaches to casing 12 by a suitable packer or liner hanger 20. Still referring to FIG. 1A, in the next step, a window 22 is milled in casing 12 at the cite for drilling an upper lateral wellbore. A short lateral (for example 30 feet) is then drilled and opened using an expandable drill to accept a suitably sized casing (for example, 95/8"). Referring now to FIG. 1B, an inflatable mold 24 is then run in primary wellbore 10 to window 22. Inflatable mold 24 includes an inner bladder 26 and an outer bladder 28 which define therebetween an expandable space 30 for receiving a suitable pressurized fluid (e.g., circulating mud). This pressurized fluid may be supplied to the gap 30 in inflatable mold 24 via a suitable conduit 32 from the surface. Applying pressure to mold 24 will cause the mold to take on a nodal shape which comprises a substantially vertical conduit extending through casing 12 and a laterally depending branch 34 extending from the vertical branch 33 and into the lateral 23. The now inflated mold 24 provides a space or gap 35 between mold 24 and window 22 as well as lateral 23. Next, a slurry of a suitable hardenable or settable liquid is pumped into space 35 from the surface. This hardenable liquid then sets to form a hard, structural, impermeable bond. A conventional lateral can now be drilled and completed in a conventional fashion such as, with a 7" liner and using a hanger sealing in branch 34. It will be appreciated that many hardenable liquids are well suited for use in conjunction with inflatable mold 24 including suitable epoxies and other polymers as well as inorganic hardenable slurries such as cement. After the hardenable filler has fully set, the inflatable mold 24 may be removed by deflating so as to define a pressure tight and fluid tight juncture between vertical wellbore 10 and lateral wellbore 23. Inflatable mold 24 may then be reused (or a new mold utilized) for additional laterals within wellbore 10. Thus, inflatable mold 24 is useful both in dual lateral completions as well as in multilaterals having three or more horizontal wells. In addition, it will be appreciated that the use of inflatable mold 24 is also applicable to existing wells where re-working is required and the junction between the vertical and one or more lateral wells needs to be completed. Referring now to FIGS. 2A-D, a second embodiment of a device for sealing the juncture between one or more lateral wellbores in a vertical well is depicted. As in the FIG. 1 embodiment, the FIG. 2 embodiment uses a deformable device for accomplishing juncture sealing. This device is shown in FIGS. 2A and 2B as comprising a dual bore assembly 36 which, includes a primary conduit section 38 and a laterally an angularly extending branch 40. In accordance with an important feature of this embodiment of the present invention, lateral branch 40 is made of a suitable shape memory alloy such as NiTi-type and Cu-based alloys which have the ability to exist in two distinct shapes or configurations above and below a critical transformation temperature. Such memory shape alloys are well known and are available from Raychem Corporation, Metals Division, sold under the tradename TINEL®; or are described in U.S. Pat. No. 4,515,213 and in "Shape Memory Alloys", L. McDonald Schetky, Scientific American, Vol. 241, No. 5, pp. 2-11 (Nov. 1979), both of which are incorporated herein by reference. This shape memory alloy is selected such that as dual bore assembly 36 is passed through a conventional casing as shown at 41 in FIG. 2D, lateral branch 40 will deform as it passes through the existing casing. The deformed dual bore assembly 36 is identified in FIG. 2C wherein main branch 40 has deformed and lateral branch 38 has been received into the moon shaped receptacle of deformed branch 40. In this way, deformed bore assembly 36 has an outer diameter equal to or less than the diameter of casing 42 and may be easily passed through the existing casing. A pocket or window 42 is underreamed at the position where a lateral is desired and deformed bore assembly 36 is positioned within window 43 between upper and lower sections of original casing 43. Next, heat is applied to deformed bore assembly 36 which causes the dual bore assembly 36 to regain its original shape as shown in FIG. 2D. Heat may be applied by a variety of methods including, for example, circulating a hot fluid (such as steam) downhole, electrical resistance heating or by mixing chemicals downhole which will cause an exothermic reaction. If the lateral well is to be a new wellbore, at that point, the lateral is drilled using conventional means such as positioning a retrievable whipstock below branch 40 and directing a drilling tool into branch 40 to drill the lateral. Alternatively, the lateral may already exist as indicated by the dotted lines 44 whereby the pre-existing lateral will be provided with a fluid tight juncture through the insertion of conventional liner and cementing techniques off of branch 40. Referring now to FIGS. 3A-C, a method will be described for forming a pressure tight juncture between a lateral and a vertical wellbore is depicted which, like the methods in FIGS. 1 and 2, utilizes a deformation technique to form the fluid tight juncture seal. As in many of the embodiments of the present invention, the method of FIGS. 3A-C may also be used either in conjunction with a new well or with an existing well (which is to be reworked or otherwise re-entered). Turning to FIG. 3A, a vertical wellbore 10 is drilled in a conventional manner and is provided with a casing 12 cemented via cement 14 to vertical bore 10. Next, a lateral 16 is drilled at a selected location from casing 12 in a known manner. For example, a retrievable whipstock (not shown) may be positioned at the location of the lateral to be drilled with a window 46 being milled through casing 12 and cement 14 using a suitable milling tool. Thereafter, the lateral 16 is drilled off the whipstock using a suitable drilling tool. In accordance with an important feature of this embodiment, a liner 48 is then run through vertical casing 12 and into lateral 16. Liner 48 includes a flanged element 30 surrounding the periphery thereof which contacts the peripheral edges of window 46 in liner 12. Cement may be added to the space between liner 48 and lateral 16 in a known fashion. Next, a swage or other suitable tool is pulled through the wellbore contacting flanged element 50 and swaging flange 50 against the metal window of casing 12 to form a pressure tight metal-to-metal seal. Preferably, flange 50 is provided with an epoxy or other material so as to improve the sealability between the flange and the vertical well casing 12. Swage 52 preferably comprises an expandable cone swage which has an initial diameter which allows it to be run below the level of the juncture between lateral casing 48 and vertical casing 12 and then is expanded to provide the swaging action necessary to create the metal-to-metal seal between flange 50 and window 46. Referring now to FIGS. 4A through D, a method of multilateral completion in accordance with the present invention is shown which provides for the sealing of the juncture between a vertical well and multiple horizontal wells, provides ease of re-entry into a selected multiple lateral well and also provides for isolating one horizontal production zone from another horizontal production zone. Turning first to FIG. 4A, a vertical wellbore is shown at 66 having a lower lateral wellbore 68 and a vertically displaced upper lateral wellbore 70. Lower lateral wellbore 68 has been fully completed in accordance with the method of FIGS. 4A-D as will be explained hereinafter. Upper lateral wellbore 70 has not yet been completed. In a first completion step, a ported whipstock packer assembly 72 is lowered by drillpipe 73 into a selected position adjacent lateral borehole 70. Ported whipstock packer assembly 72 includes a whipstock 74 having an opening 76 axially therethrough. A packer 78 supports ported whipstock 74 in position on casing 66. Within axial bore 76 is positioned a sealing plug 80. Plug 80 is capable of being drilled or jetted out and therefore is formed of a suitable drillable material such as aluminum. Plug 80 is retained within bore 76 by any suitable retaining mechanism such as internal threading 82 on axial bore 76 which interlocks with protrusions 84 on plug 80. Protrusions 84 are threaded or anchor latched so as to mate with threads 82 on the interior of whipstock 74. It will be appreciated that lateral 70 is initially formed by use of a retrievable whipstock which is then removed for positioning of the retrievable ported anchor whipstock assembly 72. It will also be appreciated that whipstock assembly 72 may either be lowered as a single assembly or may be lowered as a dual assembly. As for the latter, the whipstock 74 and retrievable or permanent packer 78 are initially lowered into position followed by a lowering of plug 80 and the latching of plug 80 within the axial bore 76 of whipstock 74. Insertion drillpipe 74 is provided with a shear release mechanism 86 for releasably connecting to plug 80 after plug 80 has been inserted into whipstock 74. Turning now to FIG. 4B, a conventional liner or slotted liner 88 is run into lateral 70 after being deflected by whipstock assembly 72. Liner 88 is supported within vertical wellbore 66 using a suitable packer or liner hanger 92 provided with a directional stabilization assembly 94 such that a first portion of liner 88 remains within vertical wellbore 66 and a second portion of liner 88 extends from wellbore 66 and into the lateral wellbore 70. Preferably, an external casing packer (ECP) such as Baker Service Tools ECP Model RTS is positioned at the terminal end of liner 88 within lateral opening 70 for further stabilizing liner 88 and providing zone isolation for receiving cement which is delivered between liner 88 and wellbore 66, 70. After cement 94 has hardened, a suitable drilling motor such as an Eastman drilling motor 96 with a mill or bit (which preferably includes stabilization fins 98) is lowered through vertical wellbore 66 and axially aligned with the whipstock debris plug 80 where, as shown in FIG. 4C, drilling motor 96 drills through liner 88, cement 94 and debris plug 80 providing a full bore equal to the internal diameter of the whipstock assembly and retrievable packer 78. It will be appreciated that debris plug 80 is important in that it prevents any of the cement and other debris which has accumulated from the drilling of lateral opening 70 and the cementing of liner 88 from falling below into the bottom of wellbore 66 and/or into other lateral wellbores such as lateral wellbore 68. Referring now to FIG. 4D, it will be appreciated that the multilateral completion method of this embodiment provides a pressure tight junction between the multilateral wellbore 70 and the vertical wellbore 66. In addition, selective tripping mechanisms may be used to enter a selected multilateral wellbore 70 or 68 so as to ease re-entry into a particular lateral. For example, in FIG. 4D, a selective coiled tubing directional head is provided with a suitably sized and dimensioned head such that it will not enter the smaller diameter whipstock opening 76 but instead will be diverted in now completed (larger diameter) multilateral 70. Head 100 may also be a suitably inflated directional head mechanism. An inflated head is particularly preferred in that depending on the degree of inflation, head 100 could be directed either into lateral wellbore 70 or could be directed further down through axial bore 76 into lower lateral 68 (or some other lateral not shown in the FIGURES). A second coil tubing conduit 102 is dimensioned to run straight through whipstock bore 76 and down towards lower lateral 68 or to a lower depth. It will be appreciated that while the coil tubing 100, 102, may have varied sized heads to regulate re-entry into particular lateral wellbores, the whipstock axial bore 76 and 104 may also have varied inner diameters for selective re-entering of laterals. In any event, the multilateral completion scheme of FIGS. 4A-D provides an efficient method for sealing the juncture between multilateral wellbores and a common vertical well; and also provides for ease of re-entry using coiled tubing or other selective re-entry means. Additionally, as is clear from a review of the several conduits 106 and 108 extending downwardly from the surface and selectively extending to different laterals, this multilateral completion scheme also provides effective zone isolation so that separate multilaterals may be individually isolated from one another for isolating production from one lateral zone to another lateral zone via the discrete conduits 106, 108. It will further be appreciated that the embodiment of FIGS. 4A-D may be used both in conjunction with a newly drilled well or in a pre-existing well wherein the laterals are being reworked, undergo additional drilling or are used for remedial and stimulation work. Turning now to FIGS. 5A-H, still another embodiment of the present invention is shown which provides a pressure tight junction between a vertical casing and a lateral liner and also provides a novel method for re-entering multiple horizontal wells. In FIG. 5A, a vertical wellbore 110 has been drilled and a casing 112 has been inserted therein in a known manner using cement 114 to define a cemented well casing. Next in FIG. 5B, a whipstock packer such as is available from Baker Oil Tools and sold under the trademark "DW-1" is positioned within casing 112 at a location where a lateral is desired. Turning now to FIG. 5C, a whipstock 118 is positioned on whipstock packer 116 and a mill 120 is positioned on whipstock 118 so as to mill a window through casing 112 (as shown in FIG. 5D). Preferably, a protective material 124 is delivered to the area surrounding whipstock 118. Protective material 124 is provided to avoid cuttings (from cutting through window 122) from building up on whipstock assembly 118. Protective material 124 may comprise any suitable heavily jelled fluid, thixotropic grease, sand or acid soluble cement. The protective materials are placed around the whipstock and packer assembly prior to beginning window cutting operations. This material will prevent debris from lodging around the whipstock and possibly hindering its retrieval. The protective material is removed prior to recovering the whipstock. After window 122 is milled using mill 120, a suitable drill (not shown) is then deflected by whipstock 118 into window 22 whereupon lateral borewell 126 is formed as shown in FIG. 5D. Next, referring to FIG. 5E, a liner 128 is run down casing 112 and into lateral borewell 126. Liner 128 terminates at a guide shoe 130 and may optionally include an ECP and stage collar 132, a central stabilizing ring 134 and an internal circulating string 136. Next, as shown in FIG. 5F, cement is run into lateral 126 thereby cementing liner 128 in position within window 122. As in the embodiment of FIG. 4, it is important that liner 128 be positioned such that a portion of the liner is within vertical casing 112 and a portion of the liner extends from vertical casing 112 into lateral borewell 126. The cement 138 fills the gap between the junction of lateral 126 and vertical casing 112 as shown in FIG. 5F. Note that a suitable liner hanger packer may support the upper end of liner 128 in vertical casing 112. However, in accordance with an advantageous feature of this invention, liner 128 may not even require a liner hanger. This is because the length of liner 128 required to go from vertical (or near vertical) to horizontal is relatively short. The bulk of the liner is resting on the lower side of the wellbore. The weight of the upper portion of liner 128 which is in the build section is thus transferred to the lower section. Use of an ECP or cementing of the liner further reduces the need for traditional liner hangers. After the cement has hardened, the liner running tool is removed FIG. 5G) and as shown in FIG. 5H, a thin walled mill 142 mills through that portion of liner 128 and cement 138 which is positioned within the diameter of vertical casing 112. Mill 142 includes a central axial opening which is sized so as to receive retrievable whipstock 118 without damaging whipstock 118 as shown in FIG. 5H. As an alternative, a conventional mill 142 may be used which would not only mill through a portion of liner 128 and cement 138, but also mill through whipstock 118 and whipstock packer 116. After mill 142 is removed, a pressure tight junction between vertical casing 112 and lateral casing 128 has been provided with an internal diameter equivalent to the existing vertical casing 112 as shown in FIG. 5I. Preferably, the thin walled mill 142 having the axial bore 144 for receiving whipstock 118 is utilized in this embodiment. This allows for the whipstock packer assembly remain undamaged, and be removed and reinserted downhole at another selected lateral junction for easy re-entry of tools for reworking and other remedial applications. Referring now to FIGS. 6A-C and 7A-C, still another embodiment of the present invention is depicted wherein a novel side pocket mandrel apparatus (sometimes referred to as a guide means) is used in connection with either a new well or existing well for providing sealing between the junction of a vertical well and one or more lateral wells, provides re-entering of multiple lateral wellbores and also provides zone isolation between respective multilaterals. FIGS. 6A-C depict this method and apparatus for a new well while FIGS. 7A-C depict the same method and apparatus for use in an existing well. Referring to FIG. 6A, the wellbore 146 is shown after conventional drilling. Next, referring to FIG. 6B, a novel side pocket or sidetrack mandrel 148 is lowered from the surface into borehole 146 and includes vertically displaced housings (Y sections) 150. One branch of each Y section 150 continues to extend downwardly to the next Y section or to a lower portion of the borehole. The other branch 154 terminates at a protective sleeve 156 and a removable plug 158. Attached to the exterior of mandrel 148 and disposed directly beneath branch 154 is a built-in whipstock or deflector member 160. It will be appreciated that each branch 154 and its companion whipstock 160 are preselectively positioned on mandrel 148 so as to be positioned in a location wherein a lateral borehole is desired. Turning now to FIG. 6C, cement 161 is then pumped downhole between mandrel 148 and borehole 146 so as to cement the entire mandrel within the borehole. Next, a known bit diverter tool 162 is positioned in Y branch 152 which acts to divert a suitable mill (not shown) into Y branch 154. Plug 158 is removed and this mill contacts whipstock 160 where it is diverted into and mills through cement 161. Next, in a conventional manner, a lateral 164, 164' is drilled. Thereafter, a lateral liner 166 is positioned within lateral wellbore 164 and retained within the junction between lateral 164 and branch 154 using an inflatable packer such as Baker Service Tools Production Injection Packer Product No. 300-01. The upper portion of liner 166 is provided with a seal assembly 170. This series of steps are then repeated for each lateral wellbore. It will be appreciated that the multilateral completion scheme of FIGS. 6A-C provides an extremely strong seal between the junction of a multilateral borewell and a vertical borewell. In addition, using a bit diverter tool 152, tools and other devices may be easily and selectively re-entered into a particular borehole. In addition, zone isolation between respective laterals are easily accomplished by setting conventional plugs in a particular location. Turning now to FIGS. 7A-D, an existing well is shown at 170 having an original production casing 172 cemented in place via cement 174. In accordance with the method of this embodiment, selected portions of the original production casing and cement are milled and underreamed at vertically displaced locations as identified at 176 and 178 in FIG. 7B. Next, a mandrel 148' of the type identified at 148 in FIGS. 6A-C is run into casing 172 and supported in place using a liner hanger 177. An azimuth survey is taken and the results are used to directionally orient the mandrel 148' so that branches 154' will be employed in the right position and vertical depth. Next, cement 179 is loaded between mandrel 148' and casing 172. It will be appreciated that the underreamed sections will provide support for mandrel 148' and will also allow for the drilling of laterals as will be shown in FIG. 7D. Next, as discussed in detail with regard to FIG. 6C, diverter tool 152' is used in conjunction with built-in whipstock 160' to drill one or more laterals and thereafter provide a lateral casing using the same method steps as described with regard to FIG. 6C. The final completed multilateral for an existing well using a side pocket mandrel 148' is shown in FIG. 7D wherein the juncture between the several laterals and the vertical wellbore are tightly sealed, each lateral is easily re-entered for remedial and simulation work, and the several multilaterals may be isolated for separating production zones. Turning now to FIGS. 8A and 8B, an alternative mandrel configuration similar to the mandrel of FIGS. 6 and 7 is shown. In FIGS. 8A and 8B, a mandrel is identified at 180 and is supported within the casing 182 of a vertical wellbore by a packer hanger 184 such as Baker Oil Tools Model "D". Mandrel 180 terminates at a whipstock anchor packer 186 (Baker Oil Tools "DW-1" and is received by an orientation lug or key 188. Orientation lug 188 hangs from packer 186. Preferably, a blanking plug 192 is inserted within nipple profile 190 for isolating lower lateral 194. Orientation lug 188 is used to orient mandrel 180 such that a lateral diverter portion 196 is oriented towards a second lateral 198. Before mandrel 180 is run, lateral 198 is drilled by using a retrievable whipstock (not shown) which is latched into packer 186. Orientation lug 188 provides torsional support for the retrievable whipstock as well as azimuth orientation for the whipstock face. After lateral 198 is drilled, a liner 204 may be run and hung within lateral 198 by a suitable means such as an ECP 199. A polished bore receptacle 201 may be run on the top of liner 198 to tie liner 198 into main wellbore 182 at a later stage. The retrievable whipstock is then removed from the well and mandrel 180 is then run as described above. A short piece of tubing 203 with seals on both ends may then be run through mandrel 180. The tubing 203 is sealed internally in the diverter portion 196 and in the PBR 210 thus providing pressure integrity and isolation capability for lateral 198. It will be appreciated that lateral 198 may be isolated by use of coil tubing or a suitable plug inserted therein. In addition, lateral 198 may be easily re-entered as was discussed with regard to the FIGS. 6-8 embodiments. Referring now to FIGS. 9A-C, still another embodiment of a multilateral completion method using a guide means or side track mandrel will be described. FIG. 9A shows a vertical wellbore 206 having been conventionally completed using casing 208 and cement 210. Lateral wellbore 218 may either be a new lateral or pre-existing lateral. If lateral 218 is new, it is formed in a conventional manner using a whipstock packer assembly 212 to divert a mill for milling a window 213 through casing 208 and cement 210 followed by a drill for drilling lateral 218. A liner 214 is run into lateral 218 where it is supported therein by ECP 216. Liner 214 terminates at a polished bore receptacle (PBR) 219. Turning now to FIG. 9B, a sidetrack mandrel 220 is lowered into casing 208. Mandrel 220 includes a housing 226 which terminates at an extendable key and gauge ring 228 wherein the entire sidetrack mandrel may rotate (about swivel 222) into alignment with the lateral when picked up from the surface with the extendable key 228 engaging window 213. Once mandrel 220 is located properly with respect to lateral 218, packer 224 is set either hydraulically or by other suitable means. Housing 226 includes a laterally extended section which retains tubing 230. Tubing 230 is normally stored within the sidetrack mandrel housing 226 for extension (hyraulically or mechanically) into lateral 218 as will be discussed hereinafter. A seal 232 is provided in housing 226 to prevent fluid inflow from within casing 208. Tube 230 terminates at its upper end at a flanged section 234 which is received by a complementary surface 236 at the base of housing 226. Tube 230 terminates at a lower end at a round nose ported guide 238 which is adjacent a set of seals 240. Port guide 238 may include a removable material 239 (such as zinc) in the ports to permit access into lateral liner 214. After mandrel 220 is precisely in position adjacent lateral 218, tubing 230 is hydraulically or mechanically extended downwardly through housing 226 whereupon head 238 will contact a whipstock diverter 244 which deflects head 238 into PBR 219. Seals 240 will form a fluid tight seal with PBR 218 as shown in FIG. 9C. Diverter 242 may then be run to divert tools into lateral 218. Alternatively, a known kick-over tool may be used to divert tools into lateral 218. Extendable tubing 230 is an important feature of this invention as it provides a larger diameter opening than is possible if the tubular connection between the lateral and side track mandrel is run-in from the surface through the internal diameter of a workstring. As shown in FIG. 9C, the completion method described herein provides a sealed juncture between a lateral 218 and a vertical casing 208 via tubing 230 and also allows for re-entry into a selected lateral using a diverter 242 or kick-over tool for selective re-entry into tubing 230 and hence into lateral liner 214. In addition, zone isolation may be obtained by appropriate plugging of tube 230 or by use of a blanking plug below the packer. The embodiment of FIGS. 10A-B is similar to the embodiments of FIGS. 9A-C with the difference primarily residing in improved zone isolation with respect to the FIG. 10 embodiment. That is, the FIG. 10 embodiment utilizes a dual packer assembly 246 together with a separated running string 248 (as opposed to the shorter (but typically larger diameter) extendable tube 230 FIG. 9C). Running string 248 includes a pair of shoulders 250 which acts as a stop between a non-sealed position shown in FIG. 10A and a sealed position shown in FIG. 10B. The dual packer assembly 246 is positioned as part of a housing 250 which defines a modified side pocket mandrel 252. Mandrel 252 may be rotationally orientated within the vertical casing using any suitable means such as an orientation slot 254 which hangs from a whipstock packer 256. It will be appreciated that the embodiment of FIGS. 10A-B provides improved zone isolation through the use of discrete conduits 248, 248' each of which can extend from distinct multilateral borewells. Tuning now to FIGS. 11A-E, still another embodiment of the present invention is shown wherein multilateral completion is provided using a dual completion head. Turning first to FIG. 11A, a vertical wellbore is shown after being cased with casing 278 and cement 294. In accordance with conventional methods, a horizontal wellbore is drilled at 280 and a liner 282 is positioned in the uncased lateral opening 280. Liner 282 is supported in position using a suitable external casing packer such as Baker Service Tools Model RTS Product No. 30107. An upper seal bore 284 such as a polished bore receptacle is positioned at the upper end of liner 282. In FIG. 11B, a whipstock anchor packer 286 such as Baker Oil Tools "DW-1" is positioned at the base of casing 278 and provided with a lower tubular extension 288 which terminates at seals 290 received in PBR 284. In FIG. 11C, a retrievable drilling whipstock 292 is lowered into casing 278 and supported by whipstock anchor packer 286. Next, a second lateral wellbore 293 is drilled in a conventional manner (initially using a mill) to mill through casing 278 and cement 294 followed by a drill for drilling lateral 293. Lateral 293 is then provided with a liner 296, ECP 298 and PBR 300 as was done in the first lateral 280. Thereafter, retrievable whipstock 292 is retrieved from the vertical wellbore and removed to the surface. In accordance with an important feature of this embodiment, a dual completion head shown generally at 302 in FIG. 11E is lowered into the vertical wellbore and into whipstock anchor packer as shown in FIG. 11D. Dual completion head 302 has an upper deflecting surface 304 and includes a longitudinal bore 306 which is offset to one end thereof. In addition, deflecting surface 304 includes a scooped surface 308 which is configured to be a complimentary section of tubing such as the tubing identified at 310 in FIG. 11D. Thus, a first tubing 312 is stung from the surface through bore 306 of dual completion head 302, through packer 286 and into tubing 288. Similarly, a second tubing 310 is stung from the surface and deflected along scoop 308 of dual completion head 302 where it is received and sealed in PBR 300 via seals 314. It will be appreciated that the method of FIGS. 11A-D provides sealing of the juncture between one or more laterals in a vertical wellbore and also allows for ease of re-entry into a selected lateral wellbore while permitting zone isolation for isolating one production zone from another with regard to a multilateral wellbore system. Turning now to FIG. 12, still another multilateral completion method in accordance with the present invention will now be described which is particularly well-suited for selective re-entry into lateral wells for completions, additional drilling or remedial and stimulation work. In FIG. 12, a vertical well is conventionally drilled and a casing 316 is cemented via cement 318 to the vertical wellbore 320. Next, vertical wellbores 322, 324 and 326 are drilled in a conventional manner wherein retrievable whipstock packer assemblies (not shown) are lowered to selected areas in casing 31. A window in casing 316 is then milled followed by drilling of the respective laterals. Each of laterals 322, 324 and 326 may then be completed in accordance with any of the methods described above to provide a sealed joint between vertical casing 316 and each respective lateral. In accordance with the method of the present invention, a process will now be described which allows quick and efficient re-entry into a selected lateral so that the selected lateral may be reworked or otherwise utilized. In accordance with this method, a packer 328 is positioned above a lateral with a tail pipe 330 extending downwardly therefrom. To re-enter any lateral, an inflatable packer with whipstock anchor profile 332 is stabbed downhole and inflated using suitable coil tubing or other means. Whipstock anchor profile 332 is commercially available, for example, Baker Service Tools Thru-Tubing Bridge Plug. Utilizing standard logging techniques in conjunction with the drilling records, whipstock anchor profile 332 may be oriented into alignment with the lateral (for example, lateral 326 as shown in FIG. 12). Thereafter, the inflatable packer/whipstock 332 may be deflated using coil tubing and moved to a second lateral such as shown in 324 for re-entry into that second lateral. Referring to FIG. 13C, still another embodiment of the present invention is shown wherein multilateral completion is accomplished by using a production whipstock 370 having a retrievable sealing plug 372 received in an axial opening 374 through the whipstock. This production whipstock is shown in more detail in FIGS. 13A and B with FIG. 13A depicting the retrievable plug 372 inserted in the whipstock 370 and FIG. 13B depicting the retrievable plug 372 having been withdrawn. Whipstock 370 includes a suitable mechanism for removably retaining retrievable plug 372. One example of such a mechanism is the use of threading 376 (see FIG. 13B) provided in axial bore 374 for latching sealing plug 372 through the interaction of latch and shear release anchors 378. In addition, a suitable locating and orientation mechanism is provided in production whipstock 370 so as to properly orient and locate retrievable plug within axial bore 374. A preferred locating mechanism comprises a locating slot 380 within axial bore 374 and displaced below threading 376. The locating slot is sized and configured so as receive a locating key 382 which is positioned on retrievable sealing plug 372 at a location below latch anchors 378. Sealing plug 372 includes an axial hole 384 which defines a retrieving hole for receipt of a retrieving stinger 386. Retrieving stinger 386 includes one or more J slots (or other suitably configured engaging slots) or fishing tool profile 387 to engage one or more retrieving lugs 388 which extend inwardly towards one another within retrieving hole 384. Retrievable stinger 386 includes a flow-through 390 for washing. Retrievable plug 372 also has an upper sloped surface 392 which will be planar to a similarly sloped annular ring 393 defining the outer upper surface of whipstock 370. In addition, sealable plug 372 includes optional lower seals 396 for forming a fluid tight seal with an axial bore 374 of whipstock 370. As will be discussed hereinafter, whipstock 370 includes an orientation device 398 having a locator key 399. The lowermost section of whipstock 370 includes a latch and shear release anchor 400 for latching into the axial opening of a whipstock packer such as a Baker Oil Tools "DW-1". Below latch and shear release anchor 400 are a pair of optional seals 402. Turning now to FIG. 13C, a method for multilateral completion using the novel production whipstock of FIGS. 13A-B will now be described. In a first step of this method, a vertical wellbore 404 is drilled. Next, a conventional bottom lateral wellbore 406 is then drilled in a conventional manner. Of course, vertical borehole 404 may be cased in a conventional manner and a liner may be provided to lateral wellbore 406. Next, production whipstock 370 with a retrievable plug 372 inserted in the central bore 374 is run down hole and installed at the location where a second lateral wellbore is desired. It will be appreciated that whipstock 370 is supported within vertical wellbore 404 by use of a suitable whipstock packer such as Baker Oil Tools "DW-1". Next, a second lateral is drilled in the conventional manner, for example, by use of a starting mill shown at 412 in FIG. 13A being attached to whipstock 370 by shear bolt 414. Starting mill 412 mills through the casing and cement in a known manner whereupon the mill 412 is withdrawn and a drill drills the final lateral borehole 410. Preferably, lateral 410 is provided with a liner 412 positioned in place by an ECP or packer 414 which terminates at a PBR 416. In the next step, sealable plug 372 is retrieved using retrieving stinger 386 such that whipstock 370 now has an axial opening therethrough to permit exit and entry of a production string from the surface. It will be appreciated that the sealing bore thus acts as a conduit for producing fluids and as a receptacle to accommodate the pressure integrity seal during completion of laterals above the whipstock 370 which in effect protects debris from travelling downwardly through the whipstock into the lower laterals 406. Preferably, a wye block assembly is then provided onto production string 418. Wye block 410 is essentially similar to housing 150 in the FIG. 6 embodiment or housing 196 in the FIG. 8 embodiment or housing 226 in the FIG. 9 embodiment. In any case, wye block 420 permits selective exit and entry of a conduit or other tool into lateral 410 and into communication with PBR 416. In addition, wye block 420 may be valved to allow shut off of wellbore 410 on a selective basis to permit zone isolation. For purposes of re-entry, a short section of tubing may be run through the eccentric port of the wye block to seal off the wellbore packer in lateral wellbore 410 followed by sealing of the wye block. This would be appropriate if the production operator did not wish to expose any open hole to production fluids. Also, a separation sleeve may be run through the wye block isolating lateral borewell 410. It will be appreciated that additional production whipstocks 370 may be used uphole from lateral 410 to provide additional laterals in a multilateral system, all of which may be selectively re-entered and or isolated as discussed. An example of additional a lateral wellbore is shown at 422. Finally, it will be appreciated that while the method of FIG. 13C was described in conjunction with a new wellbore, the multilateral completion method of FIG. 13C may also be utilized in conjunction with reworking and completing an existing well wherein the previously drilled laterals (drainholes) are to be re-entered for reworking purposes. Turning now to FIGS. 14A-K, 15A-D and 16A-C, still another embodiment of this invention for multilateral wellbore completion will be described. As in the method of FIG. 13C, the method depicted sequentially in FIGS. 14A-K utilize the whipstock assembly with retrievable sealing plug 370 of FIGS. 13A-B. It will be appreciated that while this method will be described in conjunction with a new well, it is equally applicable to multilateral completions of existing wells. In FIG. 14A, a vertical well is conventionally drilled and completed with casing 424. Next, a bottom horizontal borehole 426 is drilled, again in a conventional manner (see FIG. 14B). In FIG. 14C, a running string 428 runs in an assembly comprising a whipstock anchor/orientation device 430, a whipstock anchor packer (preferably hydraulic) 432, a nipple profile 434 and liner 436. Pressure is applied to running string 428 to set packer 432. A read-out of the orientation is accomplished via a survey tool 438 (see FIG. 14D) and transmitted to the surface by wireline 440. The running tool is thereafter released (by appropriate pulling of, for example, 30,000 lbs.) and retrieved to the surface. FIGS. 15A-D depict in detail the orientation whipstock/packer device 430. Device 430 comprises a running tool 442 attached sequentially to an orientation device 444 and a packer 446. At an upper end, running tool 442 includes an orientation key 448 for mating with survey tool 438 (see FIG. 14D). The lower end of tool 442 has a locator key 450 which extends outwardly therefrom. Running tool 442 terminates at a latch-in shear release mechanism 456 (such as is available from Baker Oil Tools, Permanent Packer Systems, Model "E", "K" or "N" Latch-In Shear Release Anchor Tubing Seal Assembly) followed by a pair of seals 458. Orientation device 444 includes an upper sloped annular surface 460. Surface 460 is interrupted by a locator slot 462 which is located and configured to be received by locator key 450. An inner bore 464 of orientation device 444 has a threaded section 466 (preferably left handed square threads). The bottom portion of device 444 is received in packer 446 which preferably is a Baker Oil Tools packer, "DW-1". Referring now to FIG. 14E, a description of the completion method will now continue. In FIG. 14E, running tool 442 has been removed so as to leave orientation device in position supported by packer 446. Next, the production whipstock assembly 370 of FIG. 12A-B is run into casing 424. As discussed above, assembly 370 includes keyed orienting device 398 (which corresponds to the lower orienting portion of running tool 442) so that assembly 370 will self-orient (with respect to mating orientation device 444) through interaction of locator slot 462 and locator key 399 and thereby latch (by mating latch mechanism 400 to threaded section 376) onto orientation device 444. FIG. 14F depicts the milling of a window 448 in casing 424 using a starting mill 412. This is accomplished by applying weight to shear bolt 414. Alternatively, if no starting mill is present on whipstock 370, a running string runs a suitable mill into the borehole in a conventional manner. After a lateral 450 has been drilled, the lateral 450 is completed in a conventional manner using a liner 452 supported by an ECP 454 and terminating at a seal bore 456 (see FIG. 14G). Thereafter, as shown in FIG. 14H, sealable whipstock plug 372 is retrieved using retrieving stinger 386 as was described with regard to the FIG. 13C embodiment. As a result, production whipstock 370 remains with an open axial bore 374. The resultant assembly in FIG. 14H provides several alternatives for re-entry, junction sealing and zone isolation. For example, in FIG. 14I, coiled tubing or threaded tubing 458 is run downhole and either stabbed into bore 374 of whipstock 370 or diverted into engagement with liner 452. Such selective re-entry is possible using suitable size selective devices (e.g., expandable nose diverter 460) as described above with regard to FIG. 13C. Thus, both wellbores may be produced (or injected into). Alternatively, as shown in FIG. 14J, the entire whipstock assembly may be removed from well casing 424 by latching in retrieving tool 462 and pulling production whipstock 370. Thereafter, with reference to FIG. 14K, a diverter mandrel 464 is run into casing 424 and mated together with orientation device 444 and packer 446. A whipstock anchor packer or standard packer 447 may be used to support diverter mandrel 464 in well casing 424. As shown in more detail in FIGS. 16A-D, diverter mandrel 464 acts as a guide means in a manner similar to the embodiments shown in FIG. 6B. In FIG. 16A, diverter mandrel 464 comprises a housing 466 having a generally inverted "Y" shape including Y branches 468, 470 and vertical branch 472. Branch 468 is adapted to be oriented towards lateral 450 and branch 470 is oriented toward the lower section of wellbore 424. Preferably, the internal diameter of branch 468 includes a nipple and seal profile 472. Branch 470 includes an orientation slot 474 for a diverter guide as well as a nipple and seal profile 476. Positioned directly below the exit of branch 468 is a diverter member 478. Finally, the lower most portion of mandrel 466 comprises an orientation device 480 and associated locator key 481 analogous to orientation device 398 on whipstock 370. Mandrel 466 allows for selective re-entry, zone isolation and juncture sealing. In FIGS. 16B and D, a diverter guide 482 is run into slot 474 and locked into nipple profile 476. Diverter guide 482 is substantially similar to removable plug 372 (FIG. 13B) and, as best shown in FIG. 16D, is properly oriented by locating a pin 484 from guide 482 in a slot 484 in mandrel 466. In this way, tools are easily diverted into wellbore 40. Alternatively, known kick-over tools may be used (rather than diverter 482) to place tools 485 into lateral 450 for re-entry. It will be appreciated that diverter guide not only allows for re-entry, but also acts to isolate production zones. In FIG. 16C, a short section of tubing 488 is shown having latches 490 and first sealing means 492 on one end and second sealing means 494 on the other end. Tubing 488 may be run downhole and diverted into sealing engagement with sealing bore 456 so as to provide a sealed junction and thereby collapse of the formation from obstruction production or re-entry. While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.	In accordance with the present invention, a plurality of methods are provided for solving important and serious problems posed by lateral (and especially multilateral) completion in a wellbore including methods for sealing the junction between a vertical and lateral well. Methods are disclosed for improved juncture sealing including novel techniques for establishing pressure tight seals between a liner in the lateral wellbore and a liner in the vertical wellbore. These methods generally relate to the installation of a liner to a location between the vertical and lateral wellbore such that the verticle wellbore is blocked. Thereafter, at least a portion of the liner is removed to reopen the blocked verticle wellbore.
You are an expert at summarizing long articles. Proceed to summarize the following text: CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims benefit of U.S. provisional patent application Ser. No. 62/218,562 filed Sep. 14, 2015, entitled “Flow Meter System,” which is hereby incorporated herein by reference in its entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not applicable. BACKGROUND [0003] Flow meters are used in various industries to measure flow rates of moving fluids. For example, flow meters are used in the hydrocarbon exploration and production industry to measure various fluids moving in pipelines or other conduits during the process of drilling and producing an oil and gas well. A well is drilled to below the surface of the earth such that oil, natural gas, and water can be extracted via the well. Some wells are used to inject materials below the surface of the earth. For example, materials or fluids can be injected below the surface of the earth to sequester carbon dioxide, store natural gas for later use, or to inject steam or other substances near an oil well to enhance recovery. In some cases, a well can be maintained or enhanced using a chemical injection management system. A chemical injection management system may inject corrosion-inhibiting materials, foam-inhibiting materials, wax-inhibiting materials, antifreeze, and/or other similar chemicals to extend the life of a well or increase the rate at which resources are extracted from a well. Such materials may be injected into the well in a controlled manner over a period of time. The chemical injection management system may include a flow meter to measure and help regulate the injected material flow rate. SUMMARY [0004] In some embodiments, a flow meter system includes a first flow sensor and first and second fluid flow conduits extending from the first flow sensor. The second fluid flow conduit may be disposed inside the first fluid flow conduit thereby forming a fluid annulus between the first and second fluid flow conduits. The first fluid flow conduit may be metal to resist a fluid pressure differential and the second fluid flow conduit may be non-metal to balance a fluid pressure across the second fluid flow conduit and attenuate noise therein. The second fluid flow conduit is attenuative to absorb ultrasound along non-fluid paths. The fluid annulus may be configured to receive a fluid to balance the fluid pressure across the second fluid flow conduit. The second fluid flow conduit may include an internal bore to receive a process fluid that is also the received fluid of the fluid annulus. The flow meter system may further include a second flow sensor, wherein the first and second fluid flow conduits extend between the first and second flow sensors. [0005] In some embodiments, the flow meter system may further include a housing surrounding the first flow sensor and an axial distance between an end face of the first and second fluid flow conduits and the first flow sensor in the first flow sensor housing. The axial distance forms a fluid chamber, and in some embodiments, the fluid chamber disposed between the fluid flow conduits and the sensor is operable to reduce fluid cavitation. The axial distance may be a pre-determined focal length for the first flow sensor. The first flow sensor may include a pre-determined window thickness. [0006] In some embodiments, the flow meter system further includes a housing surrounding the first flow sensor and a fluid inlet in the first flow sensor housing having an angled junction. In some embodiments, the angled junction serves to reduce fluid cavitation. The angled inlet may serve as a flow passage directing fluid into a fluid chamber of the sensor housing. [0007] In some embodiments, the noise attenuation of the second fluid flow conduit allows the first flow sensor to measure a laminar flow rate at high pressure. In some embodiments, the first flow sensor is configured to measure a fluid viscosity. In some embodiments, an internal bore of the second fluid flow conduit is adjustable. In further embodiments, the internal bore is configured to flow a fluid in a viscosity range of 0.1 cP to 500 cP. In some embodiments, a seal is disposed between the first and second fluid flow conduits to stagnate the received fluid in the fluid annulus. [0008] In some embodiments, a flow meter system includes metal seals axially offset from an ultrasonic piezoelectric crystal. The flow meter system may include a housing surrounding the first flow sensor and having a first metal seal between the housing and the first flow sensor, and a second metal seal between the housing and the first fluid flow conduit, wherein the first and second metal seals are axially offset relative to a crystal of the first flow sensor. In some embodiments, the flow meter system includes a first housing surrounding the first flow sensor and having a first metal seal between the first housing and the first flow sensor, a second metal seal between the first housing and the first fluid flow conduit, wherein the first and second metal seals are axially offset relative to a crystal of the first flow sensor, a second housing surrounding the second flow sensor and having a third metal seal between the second housing and the second flow sensor, a fourth metal seal between the second housing and the second fluid flow conduit, wherein the third and fourth metal seals are axially offset relative to a crystal of the second flow sensor. In some embodiments, the flow meter system is coupled to a chemical injection management system BRIEF DESCRIPTION OF THE DRAWINGS [0009] For a detailed description of exemplary embodiments, reference will now be made to the accompanying drawings in which: [0010] FIG. 1 is a schematic view of an embodiment of a well system; [0011] FIG. 2 is a schematic view of an embodiment of wellhead and chemical injection management system of the well system of FIG. 1 ; [0012] FIG. 3 is a perspective, partial phantom view of a flow meter and valve or regulator assembly of FIG. 2 ; [0013] FIG. 4 is a schematic of the architecture of the flow meter and valve or regulator assembly of FIG. 3 ; [0014] FIG. 5 is a side and end views of an embodiment of a flow meter system in accordance with principles disclosed herein; [0015] FIG. 6 is an enlarged, cross-section view of an inlet sensor body of the flow meter system of FIG. 5 ; [0016] FIG. 7 is an enlarged, cross-section view of an outlet sensor body of the flow meter system of FIG. 5 ; [0017] FIG. 8 is a cross-section view of an alternative embodiment of an inlet sensor body; [0018] FIG. 9 is a cross-section view of another alternative embodiment of an inlet sensor body and an outlet sensor body of a flow meter system; [0019] FIG. 10 is a cross-section view of a further alternative embodiment of an inlet sensor body and an outlet sensor body of a flow meter system; and [0020] FIG. 11 is a perspective view of an alternative embodiment of a flow meter and valve assembly including a plurality of flow meter assemblies or cores. DETAILED DESCRIPTION [0021] In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the disclosed embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present disclosure includes embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. [0022] Unless otherwise specified, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. Any use of any form of the terms “connect”, “engage”, “couple”, “attach”, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings. [0023] FIG. 1 is a schematic diagram showing an embodiment of a well system 100 . The well system 100 can be configured to extract various minerals and natural resources, including hydrocarbons (e.g., oil and/or natural gas), or configured to inject substances into an earthen surface 110 and an earthen formation 112 via a well or wellbore 114 . In some embodiments, the well system 100 is land-based, such that the surface 110 is land surface, or subsea, such that the surface 110 is the sea floor. The system 100 includes a wellhead 115 disposed over the wellbore 114 . The system 100 may be used to extract oil, natural gas, and other related resources from the wellbore 114 and the wellhead 115 , through a conduit 106 , and to an extraction point 104 at a surface location 102 . The extraction point 104 may be an on-shore processing facility, an off-shore rig, or any other extraction point. The system 100 may also be used to inject fluids, such as the materials noted above, into the wellbore 114 . The injected fluids may be supplied to the subsea equipment using the conduit 106 , which may include flexible jumper or umbilical lines. The conduit may comprise reinforced polymer and small diameter steel supply lines, which are interstitially spaced into a larger reinforced polymer liner. As the working pressure of the subsea equipment increases, the supply pressures and injection pressures also increase. [0024] Referring now to FIG. 2 , the wellhead 115 includes a Christmas tree or tree 108 . The tree 108 includes a valve receptacle 116 and a chemical injection management system (CIMS) 118 . When assembled, the tree 108 may couple to the well 114 and include a variety of valves, fittings, and controls for operating the well 114 . The chemical injection management system 118 is coupled to the tree 108 via the valve receptacle 116 . The tree 108 provides fluid communication between the chemical injection management system 118 and the well 114 . The chemical injection management system 118 further includes a flow valve or flow regulator assembly 120 , and as explained below, the chemical injection management system 118 may be configured to regulate the flow of a fluid through the tree 108 and into the well 114 using the flow valve assembly 120 . [0025] Referring now to FIG. 3 , a perspective and partial phantom view of the flow meter and valve assembly 120 is shown. The flow valve assembly 120 includes a housing 112 with a handle 124 , a first coupling interface 126 , and a second coupling interface 128 . In some embodiments, the coupling interfaces 126 , 128 are used to couple to the chemical injection management system 118 , the tree 108 , an ROV (remotely operated vehicle), or other portions of the wellhead 115 equipment. The housing 122 contains a flow meter 130 , a valve actuator assembly 132 , and a conduit or flowline 134 fluidly coupling an inlet 150 of the valve actuator assembly 132 to an outlet 138 of the flow meter 130 . The housing 122 may also contain other mechanical, electrical, and hydraulic components of the flow meter and valve assembly 120 . For example, and referring to FIG. 4 , the flow meter and valve assembly 120 includes an inlet or hydraulic coupler 136 fluidly coupled to the flow meter 130 . A control module 146 and a first pressure sensor 142 are electrically coupled to the flow meter 130 . In some embodiments, the flow meter 130 is an ultrasonic flow meter, and thus the control module 146 is an ultrasonic control module. An electronic control module 148 and a second pressure sensor 144 are also electrically coupled to the flow meter 130 . Fluid directed through the flow meter 130 exits the flow meter 130 at the outlet 138 , travels through the flowline 134 , and enters the valve actuator assembly 132 at the inlet 150 . In some embodiments, the valve actuator assembly 132 is a motor actuated control valve with position feedback. The valve actuator assembly 132 is fluidly coupled to an outlet or hydraulic coupler 152 of the flow valve assembly 120 . The ultrasonic control module 146 , the electronic control module 148 , and the pressure sensors 142 , 144 are used to operate the flow valve assembly 120 , and are electrically coupled to an electrical connector 140 for signal and power communication to and from the flow valve assembly 120 . [0026] Referring next to FIG. 5 , a side and end views of an embodiment of a flow meter system 200 is shown in accordance with principles of the present disclosure. In some embodiments, the flow meter system 200 is an ultrasonic flow meter system. In some embodiments, the flow meter system 200 can be used to replace the flow meter 130 of the above-described flow valve assembly 120 . The flow meter system 200 includes a first sensor or transducer end 202 and a second sensor or transducer end 204 . Coupled between the sensor ends 202 , 204 is a fluid pipe or conduit 210 . The first sensor end 202 , which may also be referred to as an inlet or upstream sensor body, includes an inlet interface 206 having a fluid inlet 220 . The second sensor end 204 , which may also be referred to as an outlet or downstream sensor body, includes an outlet interface 208 having a fluid outlet 218 and other interface mechanisms 217 , 219 . A control module canister 212 is mounted on the flow meter system 200 using clamps 214 and retainers 216 . In some embodiments, the canister 212 includes an ultrasonic control module. In some embodiments, the canister 212 is retained on the pipe 210 . [0027] Referring now to FIG. 6 , an enlarged, cross-section view of the inlet sensor body 202 is shown. The inlet sensor body 202 includes a housing 222 , a retainer plate 224 , a retainer or screw 226 , and a retainer ring 236 , which help to couple the pipe 210 to the housing 222 . The pipe 210 may be sealed against the housing 222 by a first seal ring 264 , a seal ring 265 , and a backup ring 267 . The pipe 210 includes an outer pipe or tube 228 and an inner pipe or tube 230 . Disposed between the outer pipe 228 and the inner pipe 230 is an annular gap or flow passage 232 . The inner pipe 230 includes an inner bore or flow passage 234 having an axis 235 . In some embodiments, the outer pipe 228 comprises metal. In some embodiments, the metal is steel. In certain embodiments, the metal is stainless steel. In some embodiments, the inner pipe 230 comprises a non-metal material. In some embodiments, the non-metal material is an attenuative material. In some embodiments, the non-metal material is a polymer. In certain embodiments, the non-metal material is a thermoplastic polymer. In certain embodiments, the inner pipe 230 is made from polyether ether ketone (PEEK), or glass filled PEEK. [0028] The housing 222 includes an internal bore 238 , and a sensor or transducer assembly 250 is mounted in the bore 238 . The sensor assembly 250 includes a sensor housing 252 , a piezoelectric crystal 254 , an inner support member 256 , and a biasing or retention member 258 which can be, for example, a Bellville spring. The sensor housing 252 may be sealed against the housing 222 by a second seal ring 266 , a seal ring 269 , and a backup ring 271 . In some embodiments, a threaded connection couples the sensor housing 252 to the housing 222 . The sensor housing 252 , the pipe 210 , and the housing bore 238 form a fluid chamber or cavity 240 in the sensor body housing 222 . A first dimension of the fluid chamber 240 is an axial distance D 1 between an end face 260 of the sensor housing 252 and an end face 262 of the pipe 210 . A second dimension of the fluid chamber 240 is an axial distance D 2 between the first seal ring 264 and the piezoelectric crystal 254 . In some embodiments, the first seal ring 264 is disposed adjacent the pipe end face 262 . A third dimension of the fluid chamber 240 is an axial distance D 3 between the second seal ring 266 and the piezoelectric crystal 254 . In some embodiments, the second seal ring 266 is disposed adjacent an intermediate portion of the sensor housing 252 and axially offset from the housing end face 262 and the piezoelectric crystal 254 . In some embodiments, the second seal ring 266 is axially offset upstream of or backed away from the piezoelectric crystal 254 . In some embodiments, the seal rings 264 , 266 are made from metal. The fluid chamber 240 and the sensor assembly 250 are sealed inside the sensor body housing 222 by a wired connector 270 sealed against a radial bore 272 . The wired connector 270 provides power and communications to and from the sensor assembly 250 . In some embodiments, the wired connector 270 also seals the sensor assembly 250 from the external environment. [0029] The fluid inlet 220 and the fluid chamber 240 are in fluid communication via the flow bore or passage 274 and the flow bore or passage 276 that come together at an angled junction 278 . In some embodiments, the fluid inlet 220 includes an enlarged diameter as compared to the reduced diameters of the flow passages 274 , 276 . [0030] Referring next to FIG. 7 , the second or outlet sensor end 204 is shown enlarged and in cross-section. The outlet sensor end 204 shares many of the same components as the inlet sensor end 202 , with some differences. In the interest of clarity, similar components will not be described in detail while others will be focused on. For example, the outlet sensor end 204 , like the inlet sensor end 202 , includes a housing 322 , a retainer plate 324 , a retainer or screw 326 , and a retainer ring 336 , which help to couple the pipe 210 to the housing 322 . The pipe 210 connection may further comprise an additional connection member 337 . The pipe 210 may be sealed against the housing 322 by a first seal ring 364 , a seal ring 365 , and a backup ring 367 . Furthermore, a seal ring 373 may be disposed in the fluid annulus 232 to provide a seal between the outer pipe 228 and the inner pipe 230 . [0031] The housing 322 includes an internal bore 338 , and a sensor or transducer assembly 350 is mounted in the bore 338 . The sensor assembly 350 includes a sensor housing 352 , a piezoelectric crystal 354 , an inner support member 356 , and a biasing or retention member 358 which can be, for example, a Bellville spring. The sensor housing 352 may be sealed against the housing 322 by a second seal ring 366 , a seal ring 369 , and a backup ring 371 . In some embodiments, a threaded connection couples the sensor housing 352 to the housing 322 . The sensor housing 352 , the pipe 210 , and the housing bore 338 form a fluid chamber or cavity 340 in the sensor body housing 322 . A first dimension of the fluid chamber 340 is an axial distance D 4 between an end face 360 of the sensor housing 352 and an end face 362 of the pipe 210 . A second dimension of the fluid chamber 340 is an axial distance D 5 between the first seal ring 364 and the piezoelectric crystal 354 . In some embodiments, the first seal ring 364 is disposed adjacent the pipe end face 362 . A third dimension of the fluid chamber 340 is an axial distance D 6 between the second seal ring 366 and the piezoelectric crystal 354 . In some embodiments, the second seal ring 366 is disposed adjacent an intermediate portion of the sensor housing 352 and axially offset from the housing end face 362 and the piezoelectric crystal 354 . In some embodiments, the second seal ring 366 is axially offset downstream of or backed away from the piezoelectric crystal 354 . In some embodiments, the seal rings 364 , 366 are made from metal. The fluid chamber 340 and the sensor assembly 350 are sealed inside the sensor body housing 322 by a wired connector 370 sealed against a radial bore 372 . The wired connector 370 provides power and communications to and from the sensor assembly 350 . In some embodiments, the wired connector 370 also seals the sensor assembly 350 from the external environment [0032] The fluid chamber 340 is in fluid communication with a fluid outlet 320 of the sensor body housing 322 . [0033] In operation, a fluid, such as a chemical injection or other process fluid, is directed to the fluid inlet 220 of the inlet sensor end 202 . The fluid then flows through the passage 274 , through the angled junction 278 , through the passage 276 , and into the fluid chamber 240 . In some embodiments, the angled junction 278 is designed to reduce cavitation in the fluid flowing therethrough and that is entering the fluid chamber 240 . In some embodiments, one or more of the fluid passages 274 , 276 are adjustable in diameter. For example, the diameters are adjustable between 5 mm, 6 mm, 7 mm, 8 mm, and other desirable diameters. In some embodiments, the fluid chamber 240 provides a volume in which the flowing fluid is allowed to slow down. In some embodiments, the reduction in velocity of the flowing fluid reduces cavitation in the fluid. In some embodiments, the velocity reduction causes the fluid to reach a steady state just prior to entering the tube flow bore 234 . Consequently, in some embodiments, the fluid chamber 240 is an anti-cavitation, pro-steady state fluid chamber providing a more stable fluid flow to the internal bore 234 of the pipe 210 . The angled flow passage just prior to the fluid chamber 240 can aid in the anti-cavitation effects in the fluid. The volume of the fluid chamber is determined by the diameter of the internal bore 238 and the axial distance D 1 . In some embodiments, the axial distance D 1 is 0.5 in., but can also be other distances. [0034] Fluid then flows from the fluid chamber 240 and into the pipe flow bore 234 as well as the fluid annulus 232 between the outer pipe 228 and the inner pipe 230 . In some embodiments, the process fluid directed into the annulus 232 is allowed to stagnate therein because of the sealing of the seal ring 373 at the outlet sensor end 204 . In some embodiments, the seal 373 prevents an unmetered flow of fluid through the annulus 232 . Thus, the process fluid in the annulus 232 is at the same or substantially the same pressure as the process fluid flowing in the bore 234 . Consequently, there is little or no pressure differential across the inner pipe 230 , i.e., the inner pipe 230 is pressure-balanced. Because the inner pipe 230 is preferably made from an attenuative material, it absorbs ultrasound waves such that non-fluid paths of sound are absorbed while the inner pipe 230 is not subjected to high stress. Instead, because the annulus 232 fluid is at the process fluid pressure, the outer metal pipe 228 withstands the high stresses generated by the process fluid pressure differential. Thus, in one aspect, the outer pipe 228 is a pressure backup pipe to the inner attenuative pipe 230 . In some embodiments, the process fluid pressures are 30,000 psi or above. In some embodiments, the internal flow bore 234 is adjustable in diameter. For example, the diameter is adjustable between 5 mm, 6 mm, 7 mm, 8 mm, and other desirable diameters. [0035] As shown by the distances axial D 2 , D 3 , D 5 , and D 6 , the metal seals are axially offset from the piezoelectric crystals. Distancing the metal seals form the piezoelectric crystals helps to increase acoustic isolation of the piezoelectric crystals. [0036] The flow meter system embodiments described above can be used to measure laminar fluid flow in high pressure systems with ultrasound. In some embodiments, the process fluid being measured ranges in viscosity from 0.1 cP to 500 cP, and such viscosities can be measured by the flow meter systems described herein. At laminar, and super laminar, flow rates the fluid velocity is low. Consequently, the time difference between pulses of ultrasound travelling upstream and downstream can be small (for example, nanoseconds) which makes repeatable measurement of the time difference (and thus velocity) challenging due to the noise that transmits between the two ultrasonic transducers via non-fluid paths. Such noise can affect processing of the ultrasonic signals. Further, high fluid pressure (such as 30,000 psi) will affect the materials of the pipes and transducers, which must be able to withstand high stresses generated by such high pressures. As described above, the inner pipe is made of an attenuative material that will absorb the non-fluid path noise, such as the sounds transmitted by solid components. The attenuative, non-metal inner pipe is surrounded by process fluid such that it is pressure-balanced, and the high pressure of the process fluid is transferred to the more robust outer metal pipe. The pressure-balancing annulus is disposed between the inner and outer pipes, thus it extends along the pipe 210 . In some embodiments, the pressure-balancing is along the pipe 210 only, meaning the pressure-balancing is limited to the metering run only. [0037] In the embodiments described above, the distances D 1 and D 2 can be pre-determined or chosen for optimum focal lengths between the transducer face and the pipe face. In some embodiments, the pre-determined optimum focal length is 0.5 in., though other focal lengths are chosen for desired results in other embodiments. In some embodiments, one or more of the transducers may include a pre-determined window thickness, for example, of 0.375 in. In some embodiments, a window thickness is the portion of the sensor housing 252 having an axial length of D 2 minus D 1 in FIG. 6 . In some embodiments, a window thickness is the portion of the sensor housing 352 having an axial length of D 5 minus D 4 in FIG. 7 . [0038] Referring to FIG. 8 , an alternative embodiment of an inlet sensor body 400 is shown in cross-section. In certain embodiments, features of the sensor assembly are adjusted as compared to embodiments described above. For example, the size and shape of a sensor housing 452 of a sensor assembly 450 can vary at such locations as an end face 460 and a threaded connection 455 . Other features are similar or vary only slightly from other embodiments described herein. For example, a fluid chamber 440 separates the sensor assembly 450 from an end face 462 of the pipe 210 . The pipe 210 includes the fluid annulus 232 which can receive and stagnate process fluid for pressure balancing. An angled fluid inlet 478 carries fluid to the fluid chamber 440 . [0039] Referring to FIG. 9 , a cross-section view of another alternative embodiment of an inlet sensor body 502 and an outlet sensor body 504 of a flow meter system 500 is shown. Certain features are adjusted as compared to embodiments described above. For example, the physical configurations of the sensor assemblies and adjacent structure are adjusted. A sensor assembly 550 next to an angled fluid inlet 578 includes an end face 560 that is in close proximity to an end face 562 of a flow conduit or metering pipe 510 . In the outlet sensor body 504 , a sensor assembly 552 includes an end face 554 that is in close proximity to an end face 556 of the metering pipe 510 . Further, the piezoelectric crystals of the sensor assemblies 550 , 552 are in-line and are not loaded or are uncompressed. Additionally, the angled fluid inlet 578 is directly coupled into the metering pipe 510 at a fluid connection 515 . [0040] Referring next to FIG. 10 , a cross-section view of a further alternative embodiment of an inlet sensor body 602 and an outlet sensor body 604 of a flow meter system 600 is shown. Certain features are adjusted as compared to embodiments described above. For example, the physical configurations of the sensor assemblies and adjacent structure are adjusted. A sensor assembly 650 next to an angled fluid inlet 678 includes an end face 660 that is in close proximity to an end face 662 of a flow conduit or metering pipe 610 . In the outlet sensor body 604 , a sensor assembly 652 includes an end face 654 that is in close proximity to an end face 656 of the metering pipe 610 . Further, the piezoelectric crystals of the sensor assemblies 650 , 652 are not in-line but at right angles, and are loaded or are compressed. Additionally, the angled fluid inlet 678 is directly coupled into the metering pipe 610 at a fluid connection 615 . [0041] Referring to FIG. 11 , a perspective view of an alternative flow meter system 700 is shown, having a plurality of flow meter assemblies or cores 702 , 704 in a single assembly. [0042] According to various embodiments disclosed herein, a flow meter system is presented which can accurately measure low or very low flow rate or velocity of the process fluid using ultrasonic transducers. Further, various embodiments of the flow meter system can accurately measure viscous fluids with ultrasonic transducers. The flow meter system embodiments are configurable to variously measure fluid velocity, fluid flow rate, fluid viscosity, fluid pressure, and other fluid characteristics, or a combination thereof. [0043] The above discussion is meant to be illustrative of the principles and various embodiments of the present disclosure. While certain embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the disclosure. The embodiments described herein are exemplary only, and are not limiting. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.	A flow meter system is disclosed that includes a first flow sensor and first and second fluid flow conduits extending from the first flow sensor. The second fluid flow conduit may be disposed inside the first fluid flow conduit thereby forming a fluid annulus between the first and second fluid flow conduits. The first fluid flow conduit may be metal to resist a fluid pressure differential and the second fluid flow conduit may be non-metal to balance a fluid pressure across the second fluid flow conduit and attenuate noise therein. The fluid annulus may be configured to receive a fluid to balance the fluid pressure across the second fluid flow conduit.

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