document: This is a continuation of application Ser. No. 08/182,910 filed on Jan. 14, 1994, now abandoned. 
      
      
       BACKGROUND OF THE INVENTION 
       1. Field of the Invention 
       The invention is directed to the field of installing wiring devices to ganged boxes mounted in building walls and more particularly to the provision of cover plate devices which can be used to cover such wiring devices to prevent unwanted access to such wiring devices and at the same time provide a finished look without exposed fasteners. 
       2. Description of the Prior Art 
       At present when it is desired to install a wiring device such as a switch, a receptacle, a duplex receptacle, a combination receptacle and switch, etc., in a wall of a building, whether public, commercial or residential, it is necessary to cut a hole into such wall and install a ganged box adjacent the hole by attaching such box to a stud or the like. The ganged box is hollow to receive such wiring devices and provides pairs of mounting ears for mounting the wiring devices within and to the box. The size of the box is selected to accept all the wiring devices required at that location and the number of pairs, of mounting ears will be equal to the number of possible wiring devices which the box can receive. Once the wiring device is connected to the various conductors it will service, the wiring device is screwed to at least one pair of ears to mount the wiring device in and to the box. When all wiring devices are in place a cover plate having suitable apertures through it will be installed over the exposed wiring devices and the ganged box. The method of fastening the cover plate to the wiring devices is to use screws which pass through the cover plate and are received in threaded apertures in such wiring devices. The usual arrangement of mounting screws is one between each duplex receptacle and two, one to each side, for a switch. Thus, when a prior art wiring system containing two duplex receptacles and a switch was complete, one could see four exposed mounting screws. This made the completed job unsightly and could expose the user to a shock hazard if the correct insulation were not used during assembly. 
       One prior art approach to hide these unsightly and potentially hazardous fasteners is shown in U.S. Pat. No. 4,873,396 issued Oct. 10, 1988 to Guity-Mehr. The cover plate was fashioned with an M-shaped groove near the bottom of the plate&#39;s back surface which could be positioned under the head of the lower fastening screw used to anchor the wiring device to the ganged box mounting ear. This mounting screw would have to be mounted so that the proper length of its body remained outside of the wiring device to be gripped by the M-shaped groove. If the screw was not sufficiently installed the cover plate would be free to rattle and if the screw was installed too deeply the M-shape groove could not be positioned under the screw head. 
       Once the cover plate was positioned with the M-groove under the mounting screw, the cover plate is positioned so that the second mounting screw can be installed in a recessed groove in the front of the cover plate and screwed into the wiring device. Then a screw groove cover is fitted over the screw groove to hide the screw head and the screw groove. 
       SUMMARY OF THE INVENTION 
       The present invention overcomes difficulties noted above with respect to the devices of the prior art. 
       The present invention provides a cover plate device that is quickly and easily installed using simple tools and available fasteners and which can be quickly and easily removed and can be fit upon walls that are not flat and even. 
       This is accomplished by a two part device, the first an attachment member which is installed over a wiring device and mounted to such wiring device. The attachment member is symmetrical about its longitudinal and transverse axis so that there is no concern for its orientation. At its opposed, transverse ends, latching pawls are placed to each side of a central tab used to separate the cover plate member from the attachment member. 
       The second part is a cover plate member which has no fastener holes extending through it and only has apertures to receive the wiring device projections as needed. A ridge extends about the periphery of the rear face of the cover plate member, and along the inside of its top transverse end it contains two saw-tooth shaped racks to receive in locking engagement the associated latching pawls of the attachment member. In the bottom transverse end, the two saw-tooth shaped racks flank a slot through which a small tool of appropriate shape can be inserted to contact the tab of the attachment member and employ it as a fulcrum to pry off the cover plate member latched to the attachment member. The use of multi-step racks allows each pawl to mate with its associated rack independently and thus accommodate variations in the flatness or evenness of the wall. This flatness or evenness is a greater problem as the cover plate member is increased in size to cover many wiring devices installed in ganged boxes. It is an object of this invention to provide an improved cover plate device for wall mounted electrical wiring devices. 
       It is another object of this invention to provide an improved cover plate device for wall mounted electrical wiring devices having no visible fasteners when installed. 
       It is yet another object of this invention to provide an improved cover plate device for wall mounted electrical wiring devices which is quickly and easily installed or removed. 
       It is still another object of this invention to provide a two part device, one of which is installed using available fasteners and the second is installed to the first without visible fasteners. 
       It is a further object of the invention to provide a cover plate device which can be properly positioned over wiring devices installed in a wall which is not flat or even. 
      
      
       Other objects and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings which disclose, by way of example, the principles of the invention and the best modes which are presently contemplated for carrying them out. 
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings in which similar elements are given similar reference characters. 
       FIG. 1 is a front prospective view of the cover plate device installed over a wall mounted rocker switch in accordance with the instant invention. 
       FIG. 2 is an exploded view of the device of FIG. 1. 
       FIG. 3 is a front prospective, exploded view of the device of FIG. 1, showing the assembly of a first portion of the cover plate device over a wall mounted wiring device with the cover plate member separated to permit viewing of the assembly of the first portion with the wiring device. 
       FIG. 4 is a side elevational view, in section, of the cover plate member of FIG. 3 taken along the lines 4--4. 
       FIG. 5 is a side elevation, partially in section, of the cover plate member as shown in FIG. 4 installed upon the attachment member of the invention. 
       FIG. 5a is a fragmentary, enlarged side elevation of the latching pawl of the attachment plate engaging the saw-tooth rack of the cover plate, both of which are shown in FIG. 5. 
       FIG. 5b is a fragmentary, enlarged side elevation in section of the cover and tab of the attachment plate to indicate how the two components can be separated following latching. 
       FIG. 6 is an exploded view of a cover plate device according to the invention to be used with two wiring devices. 
       FIG. 7 is an exploded view of a cover plate device according to the invention to be used with three wiring devices. 
       FIG. 8 is an exploded view of a cover plate device according to the invention to be used with four wiring devices. 
      
      
       DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       Turning now to FIGS. 1 to 5, there is shown a cover plate device 10 constructed in accordance with the concepts of the invention. A suitable aperture 14 is cut into wall 12 to gain access to a ganged box mounted to a stud 15 or to permit installation of a suitable box to an adjacent stud or directly to the material of the wall (such as plasterboard). The ganged box 13 will be large enough to accept as many wiring devices as are needed. The ganged box 13 is made of metal or plastic and has one or more openings to permit the introduction of cable into the interior of the box 13, it has mounting means 19 to permit it to be anchored to an adjacent stud and pairs of mounting ears 21, each of which contains a threaded aperture 23 to which can be fastened the mounting screws of the wiring device such as, for example, rocker switch 18. In the normal order of things the wiring device is fastened to the box mounting ears 21 and the cover plate is then attached by screws to the wiring device, leaving at least one exposed mounting screw. The mounting screws have a small square of insulation about them to insulate the wiring device from the mounting ears 21 of ganged box 13. Absent such insulation the wiring device and the cover plate could become electrically hot if the ganged box comes into contact with a bare, hot conductor. 
       The device of FIG. 1 clearly shows that when completely installed cover plate device 10 has no exposed mounting screws or other visible metal hardware. The only visible parts are the cover plate 16 and the rocker switch 18. 
       As shown in FIG. 2, the rocker switch 18 has a body 20 which extends into the ganged box 13 and two lugs 22, one at each end of body 20, with threaded mounting holes 24 in each of such lugs 22. A mounting screw similar to screw 26 is passed through the unnumbered elongate mounting slots to mount switch 18 to the mounting ears 21 of the ganged box 13 as best seen in FIG. 3. With the instant invention an attachment plate 30 is attached to the switch 18 or other wiring device by the use of mounting screws 26. These pass through apertures 32 in the attachment plate 30 and engage the threaded apertures 24 in the lugs 22 of switch 18. Attachment plate 30 also contains a main aperture 34 of a shape complementary with the profile of the wiring device which extends through it. (See FIG. 3) The aperture 34 in FIG. 2 is rectangular to accept rocker switch 18. 
       At each end 36 and 38, respectively, of attachment plate 30 are placed two latching pawls 40 and two latching pawls 42, respectively. As best seen in FIG. 5a, the pawl 42 has a vertical leg 44 which is an extension of attachment plate 30 but is much thinner and terminates in an angled leg 46 which extends at about a 45° angle with respect to the horizontal top edge of end 38 of attachment plate 30. 
       Between each of the two latching pawls 40 and 42 is a tab 48 which will act as a tool pivot point for prying off the cover plate 16 when assembled to the attachment plate 30. As will be described below, a slot in the cover plate 16 lower edge provides access for the insertion of a small flat tool. 
       The cover plate 16 is proportioned to fit over the entire attachment plate 30 as well as the ganged box into which a single wiring device, such as rocker switch 18, is placed and to which it is fastened. Thus, the cover plate 16 is slightly longer than the wiring device along the longitudinal axis but is between 30 and 40 percent wider along the transverse axis. The width varies depending upon how many boxes are ganged. 
       The cover plate 16 has a front face 60 which is unbroken except for the central aperture 62 configured to the profile of the wiring device that extends through it and as shown in FIG. 2 is rectangular and a back face 64. Side walls 66 and 68 smoothly join the faces 60 and 64 to give a rounded upper edge to plate 16. The walls 66 and 68 flare out as they extend from plate 16 so that the bottom edge of walls 66 and 68 are further apart than where they join cover plate 16. End walls 70 and 72 also smoothly join faces 60 and 64 and further side walls 66 and 68 so that there are no sharp edges between the walls or between the walls and faces 60 and 64. 
       Placed in the bottom end wall or ridge 72 is a slot 74 which provides access to the tab 48 as is best seen in FIG. 5b. A small, flat tool blade, such as screw driver blade 76, is moved through slot 74 in end wall 72 to contact both the outer surface of tab 48 and the back wall of slot 74. By moving the blade 76 in a counterclockwise direction using the back wall of slot 74 as a fulcrum the force applied to tab 48 will separate cover plate 16 from attachment plate 30. 
       To attach cover plate 16 to attachment plate 30 the pawls 40, 42 on attachment plate 30 are made to engage the saw-tooth shaped racks 80 on the inner surfaces of end walls or ridges 70 and 72 of cover plate 16. There are two racks 80 on end wall or ridge 70 and two racks 80 on end wall or ridge 72. Each rack 80 contains a number of saw-tooth shaped teeth 82 each having an inclined front face 84 and a vertical back face 86. As best seen in FIG. 5a, as angled leg 46 engages the inclined front face 84 the pawl 42 is made to deflect in a counterclockwise direction sufficiently so that pawl 42 can get by the tip of the first tooth 82. Once leg 46 is past the tip of tooth 82, it can return to its initial position and take a position between the vertical back face 86 of the first tooth 82 and the inclined front face 84 of a second tooth 82. This operation can be repeated as many times as needed to get the bottom edges of the cover plate 16 as close to the mounting wall as possible. Since each of the racks 80 and pawls 40, 42 are independently operated it is possible to get the cover plate 16 to closely follow the mounting wall contour even if the wall is not flat, even, plane etc. This ability to follow the wall contour is even more appreciated where the cover plate 16 is large, such as with a cover plate to cover four ganged boxes. 
       Once the angled leg 46 of the pawl 42 returns to its original position, any attempt to dislodge the cover plate 16 from the attachment plate 30 is opposed by the engagement of the vertical free edge of angled leg 46 with the vertical back face 86 of the tooth 82. However, since tool 76 can apply a great deal of force to tab 48 it is possible to separate plates 16 and 30. 
       FIG. 6 shows a cover plate device for two wiring devices. The two wiring devices can be placed in a double ganged box 31 made up of two single ganged boxes 13 and joined by fasteners 25 extending through the threaded apertures 29 of two joining ears 27. The double ganged box 31 provides four mounting ears 21 each with a threaded aperture 23 to receive the mounting screws of the wiring devices (not shown). Additional ganged boxes 13 can be added to increase the overall ganged box arrangement as required. Attachment plate 130 has two apertures 134 which are of the same configuration. However, any combination of wiring devices could be employed so that one of the apertures could be a cut-out for a duplex receptacle, and another for a toggle switch, etc. There will be three racks 80 on the interior of each of the end walls 172 and 170 (not shown) and three pawls 140, on end wall 136 and three pawls 142 on end wall 138 of attachment plate 130. Also there will be two tabs 148 which will be accessible via slots 174 in end wall 172 of cover plate 116. The attachment plate 130 is attached the same way as attachment plate 30 and the installation is completed by installing cover plate 116. Because of the independent operation of the pawls 140, 142 with their respective racks 80, the cover plate 116 will be able to compensate somewhat for irregularities in the wall in which the wiring devices are installed. 
       It appears that for any cover plate device which is to fit over an even number of ganged boxes or an even number of wiring devices there will be an odd number of racks 80 and an odd number of pawls 40,42,140, 142 and an even number of slots 74, 174 and an even number of tabs 48, 148. 
       FIG. 8 shows an arrangement to cover the installation of four ganged boxes and the four wiring devices they could mount. According to the observations made above, for an even number of wiring devices to be installed with the proper attachment plate 330 and cover plate 316, there will be four cut-outs or apertures 334 in attachment plate 330 and four cut-outs or apertures 362 in cover plate 316; five pawls 340 on end wall 336 and five pawls 342 on end wall 338 which each cooperate with an associated one of the ten racks 80 of cover plate 316, some of which are shown on the inside surface of the end walls such as 372. There will also be four tabs 340 which each can be reached through one of the slots 374 adjacent the associated tab 340. 
       In FIG. 7 there is shown an arrangement to cover three wiring devices mounted in three ganged boxes (not shown) with an attachment plate 230 and cover plate 216 each of which have three apertures 234 and 262, respectively. There are four pawls 240 on end wall 236 and four pawls 242 on end wall 238. The pawls 240 and 242 will engage an associated rack 80 some of which are shown on the inside surface of the end wall 272 and the opposite end wall 270 (not shown). The three tabs 248 which are placed adjacent the slots 274 in wall 272 can be reached through those slots. 
       The order of installation of the device of FIG. 7 is substantially the same as already set forth. Attachment plate 230 is attached to the ears of the ganged boxes (not shown) using screws 226 after which the cover plate 216 is aligned and placed over the attachment plate 230 and locked thereto by the engagement of the pawls 240 and 242 with associated racks 80. 
       It should be evident now that where there is an odd number of cut-outs or apertures in the attachment plate and cover plate there will be an even number of pawls 40, 42, 240, 242, an even number of racks 80, and an odd number of tabs 48, 248 and slots 74, 274. 
       While there have been shown and described and pointed out the fundamental novel features of the invention as applied to the preferred embodiments, it will be understood that various omissions and substitutions and changes of the form and details of the devices illustrated and in their operation may be made by those skilled in the art without departing from the spirit of the invention.
summary: A cover plate device for covering a wall mounted wiring device having no visible fasteners when installed. An attachment plate is attached over and to a wiring device which has been mounted in and to a ganged box mounted adjacent an aperture in a wall. Latch pawls are arranged at the opposite longitudinal ends of the attachment plate. A cover plate member overlies the wiring device and ganged box and provides a series of recesses to receive the associated pawls in locking arrangement. Because of the number of recesses available at each pawl location, the cover plate can still be installed even if the wall is not flat or even. The attachment plate and cover plate member can be provided with various types and numbers of apertures, and the number of pawls and groups of recesses employed depend on the size of the attachment and cover plate members.