document: CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application is a continuation of provisional patent application Ser. No. 60/219,534, filed on Jul. 20, 2000, the complete disclosure of which is incorporated herein by reference. 
       
      
       
         TECHNICAL FIELD  
           [0002]    The present invention relates to movable partitions and panels, and, more particularly, to partitions and bulkheads which can be used to separate or insulate cargo during transportation or storage. The invention also relates to segregation of cargo into a plurality of areas that are maintained at different temperatures, commonly known as multi-temperature transport.  
           BACKGROUND  
           [0003]    Perishable items such as produce and meat are often transported in refrigerated trailers, railcars, or ocean-going containers that can be transported on ships, trains or trucks. Such cargo transport devices are typically equipped with a refrigeration unit which conditions the air inside the cargo space, thereby maintaining desired temperatures and humidities during transportation or storage. Refrigerated trailers, railcars and containers are typically configured so as to enclose a single, large cargo space. Their refrigeration units will accordingly maintain the entire cargo space at the same temperature and humidity unless the cargo area is somehow divided. However, when the perishable cargo does not fill the entire trailer, cooling the entire cargo area is unnecessary and costly. It causes unnecessary strain and wear on the refrigeration unit, increases fuel consumption, raises transportation costs, and lengthens the time necessary to cool the perishable cargo after any temperature aberration.  
             [0004]    Movable partitions and bulkheads having a specialized construction which permits the cargo space of trailers, rail cars, and containers to be readily divided into sections of varying sizes are known. Such bulkheads and partitions have been widely used to separate cargo areas for multi-temperature transport. The structure and configuration of partition and bulkhead systems differ somewhat depending on whether they are being deployed in a trailer, railcar, or container. Partitions currently used in refrigerated truck trailers typically extend from floor to ceiling and are generally comprised of modular wall sections. The modular sections are often mounted in channels or grooves on the trailer floor, held in place by friction, or otherwise mechanically fastened in place so as to compartmentalize trailers and truck bodies for multi-temperature food distribution. The panels are used to divide the trailer or body both longitudinally, along the long axis of the trailer, and laterally, across the width of the trailer. Some partition systems include panels that can be readily removed and placed along the sidewall of the trailer when not in use.  
             [0005]    Insulated bulkheads are panels that extend across the width of a trailer to form separate fore and aft cargo areas. Like partitions, insulated bulkheads allow a refrigerated hauler to carry two or more loads at different temperatures within the same trailer or cargo container. For instance, bulkheads may be used to separate fresh food products from frozen or dry goods. Bulkheads are optionally equipped with walk-through doors similar to those used in partitions to permit ingress to and egress from each conditioned cargo area. Due to the functional similarities between bulkheads and panels, the latter are sometimes referred to as bulkheads.  
           SUMMARY  
           [0006]    The present invention includes an improved partition system in which at least two panels are independently attached to one or more mounting assemblies such that each panel can be moved independently. In a preferred embodiment, two bulkheads or panels are slidably attached to separate pairs of ceiling-mounted rails in a refrigerated trailer such that each bulkhead or panel can be independently slid toward the front of a trailer or toward the rear of a trailer to define, in cooperation with a removable center partition wall, a plurality of different cargo areas to be maintained at different temperatures. In another preferred embodiment, two panels in the form of half-width bulkheads are releasably secured to one another and independently, slidably attached to ceiling of the trailer such that each half-width bulkhead can be independently raised and lowered with a minimum of fore and aft clearance. 
         
      
      
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0007]    [0007]FIG. 1 is a perspective view of a trailer containing center partition panels extending along the long axis of the trailer, two horizontal panels, and a rail and trolley system for moving the horizontal panel in the axial direction;  
           [0008]    [0008]FIG. 2 is a plan view of rail system shown in FIG. 1;  
           [0009]    [0009]FIG. 3 is a perspective view of a rail system, trolley assembly slideably attached to the rail system, and a panel hingedly attached to the rail system;  
           [0010]    [0010]FIG. 4 is a perspective view of the rail systems, trolley assembly, and panel after the panel has been raised into a stowed position by a lift mechanism; and  
           [0011]    [0011]FIG. 5 is a perspective view of a lift mechanism.  
           [0012]    Like reference numbers and designations in the various drawings indicate like elements. 
       
      
       DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
         [0013]    Referring to FIG. 1, the trailer  10  encloses a cargo space. The cargo space is separated into a plurality of zones or areas  12 ,  14  that can optionally be maintained at different temperatures. Center partition panels  16  extend along the long axis of the trailer and separate the trailer into a left zone  12  and a right zone  14 . The partition panels  16  can have various interfitting modular constructions, as is known in the art. Lateral panels  18 ,  20  extend laterally from the center partitions  16  to the left and right trailer walls. The right panel  20  is mounted forward of the left panel  18 , thereby decreasing the volume of the right zone  14  relative to the left zone  12 . Accordingly, the volume of air in the right zone  14  that must be temperature controlled is minimized, which in turn maximizes efficiency and reduces strain on the temperature control system.  
           [0014]    The panels  18 ,  20  are slidably attached to the rails  22  with a trolley assembly  24 . The panels are hingedly attached to trolley assembly  24 , and the trolley assemblies are slidably attached to the rails  22 ,  23 . The trolley assemblies permit the panels  18 ,  20  to be moved in the fore and aft direction and to be “raised” like garage doors and secured to the ceiling when not in use, as shown in FIG. 4 and described in more detail below.  
           [0015]    Those skilled in the art will appreciate that the panel, trolley assembly, and rail system can be implemented in a wide variety of configurations. For instance, the rails may be advantageously installed on the side walls of the trailer, thereby enabling the panels  18 ,  20  to open like a standard household door. The mounting assembly is preferably a trolley assembly, but may optionally be replaced with any mechanism that permits rotational, slideable, or hinged movement between the rails and the bulkhead. It is not necessary that the trolley or other mounting assembly permit continuous slidable movement of the bulkhead relative to the rails. Similarly, the rails may be replaced with other receiving members that cooperate with the selected mounting means. It is not necessary that the receiving means be unitary, continuous, or disposed along the long axis of the trailer. For instance, the receiving means can be a series of individual receptacles disposed along the ceiling of the trailer.  
           [0016]    [0016]FIG. 2 is a plan view of the rail assembly shown in FIG. 1. In the depicted embodiment, the receiving members comprise longitudinal rails  22 ,  23  having an internal channel adapted to receive a slidable member, preferably a roller. End rails  26  provide a mount for the ends of the longitudinal rails  22 ,  23  and also function as a trolley stop. Fixed to the end rails  26  are lift mechanisms  28  and safety chains  30 , the functionality of which is described below. Mounting flanges  31  permit the rails to be fastened to the trailer walls or ceiling with standard fasteners.  
           [0017]    Here again, various modifications can be readily made without departing from the invention. For instance, end rails  26  can be replaced with end caps or can be omitted entirely. The end rails  26  can also be advantageously replaced with half-width movable rails that span and slidably engage the two longitudinal rails on the left  22  and the two longitudinal rails on the right  23 , respectively. Each moveable rail can be fitted with lift mechanisms  28  and safety chains  30  such that each moveable rail can be slid into position relative to each panel before each is lifted into an inoperative or stowed position. Additional longitudinal rails  22 ,  23  can be added to accommodate additional panels or panels of different widths.  
           [0018]    [0018]FIG. 3 is a perspective view of the panels  18 ,  20 , the trolley assembly  24 , and the rails  22 ,  23 . The trolley assembly consists of hinge plates  36  that are fixedly secured to the panels  18 ,  20 , a hinge rod  32 , and trolleys  34 . The trolleys  34  serve to suspend the panel from the rails  22 . Trolleys  34  include rollers  35  which permit the bulkhead to be slid into a desired longitudinal position, as shown in FIG. 1. The hinge mechanism  32 ,  36  permits the panel to rotate about the hinge rod  32 , as shown in FIG. 4.  
           [0019]    The panel is moved from the position shown in FIG. 3 to the position shown in FIG. 4 by lifting the bottom of the panel  18  up and to the rear of the trailer. The panel  18  is moved fore or aft, as needed, to position the base of the panel  18  proximate to the strap  38  having a hook  40 . The hook  40  is secured to the base  42  of panel  18 , preferably by attachment to a cooperating receptacle. The strap  38  is pulled downward to raise the base  42  of the panel to the ceiling of the trailer. The chains  30  can be attached to the base  18  of the panel to safeguard against unintended release of the panel  18  from the stowed position.  
           [0020]    Referring to FIGS. 3 and 4, the assemblies may be advantageously modified to provide additional or different functionalities. The trolley assembly  32 ,  34 ,  36  can optionally be replaced with any known mounting mechanism that cooperates with the rails. The mounting means may comprise a post or flange integrally molded into the panel  18  and adapted to be received into the rails  22 . As further examples, the mounting means may include i) a flat slidable member that engages an interior surface of the rail member and is hingedly attached to the bulkhead, ii) an integral, one piece, arcuate tab attached to the top of the bulkhead that can be inserted into one of a plurality of longitudinally arranged receiving means at a predetermined angle such that the tab locks the bulkhead into place as the bulkhead is lowered into a vertical position, iii) a hinge member that releasably locks into one of a plurality of longitudinally disposed receiving means, or iv) any other known mounting mechanism suitable for such mechanical attachment. Likewise, rails  22 ,  23  can be replaced with other mechanisms that cooperate with the selected mounting mechanism. For example, the rails  22 ,  23  may be replaced with a continuous rail having a plurality of axially disposed apertures for receiving cooperatively configured mounting means or a series of independently mounted receiving members for receiving cooperatively configured mounting means. As noted above, the rail members can optionally be mounted on a vertical surface, such as a trailer wall. Mounting members can thus be selected to enable the bulkheads to swing open like a door, slide in the axial direction in which the rail members are mounted, or be readily removed and reinstalled in another set of receiving members. The foregoing modifications are illustrative only and are not intended to comprise a comprehensive list of all modifications that can be made to the instant apparatus without departing from the invention.  
           [0021]    [0021]FIG. 5 is a detailed view of the strap  38  and cooperating locking mechanism shown in FIG. 4. The strap  38  is positioned over guide pins  44 ,  46 . Flange  48  is rigidly attached to cam  50 . In use, the left portion  52  of the strap  38  is attached to the base  42  of the panel  18  either directly or through a suitable cooperating attachment means such as a hook and a mateable receptacle. The right portion  54  of the strap  38  is pulled downward until the panel  18  is in the desired stowage position. Then the flange  48  is forced upward by action of a spring (not shown), thereby forcing cam  50  against strap  38  and locking the strap in place. To lower the bulkhead  18 , the right portion  54  of the strap  38  is pulled downward, which in turn forces flange  48  downward to the depicted, open position. The strap is then free to travel over guide pins  44 ,  46  as long as the right portion of the strap is maintained in the depicted, vertical position in substantial tension, which holds flange  48  in the open position. When the end of the strap portion  54  is raised upwards and to the rear of the trailer, spring force causes the flange and cam assembly to rotate counterclockwise, causing the cam  50  to lock the strap  50  in place. Accordingly, the base  42  of the bulkhead  18  is lowered toward the floor of the trailer by holding the strap portion  54  in a vertical position as the strap is pulled over pins  44 ,  46  by the weight of the bulkhead.  
           [0022]    The panels  18  and  20  may be advantageously used without center partition panels  16 . For instance, the two panels may be placed side by side and fastened together to make a full-width horizontal bulkhead. A user can advantageously separate the panels, or half-width bulkheads, from one another prior to raising the panels in the manner described above. Further, because each panel is independently and slideably mounted, the amount of rearward clearance needed to raise the panel is reduced significantly. The top of the panel can be slid forward as the bottom is raised rearwardly, which permits the panel to be lifted and stowed even when pallets and cargo are stacked close to the panel.  
           [0023]    The panels of the instant invention may be secured relative to one another with a variety of known means. For instance, the panels can be equipped with cooperating straps and buckles. The panels can alternately be equipped with cooperating channels, grooves, flanges, polymeric seals, or locking pins.  
           [0024]    A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various additional modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.
summary: An improved bulkhead and partition system in which at least two panels are independently attached to mounting members such that each panel can be moved independently. In a preferred embodiment, two bulkheads or panels are slidably attached to separate pairs of ceiling-mounted rails in a refrigerated trailer such that each bulkhead or panel can be independently slid toward the front of a trailer or toward the rear of a trailer to define, in cooperation with a removable center partition wall, a plurality of different cargo areas to be maintained at different temperatures.