Abstract:
A lightweight roll-up door comprises multiple lightweight panels that can be transversely installed/removed with a simple hinge assembly. The panels are hinged about one edge and have outer complementary arcuate portions that fill the gap at the edges of the door as the panels rotate about the hinge. The panels are extruded from a lightweight material. Additionally, the panels are structurally capable of supporting the necessary door hardware without deformation or breakage. A latch assembly is mounted to an extruded bottom panel forming a latch recess for receiving the latch assembly and with multiple mounting supports disposed within the hollow interior and extending between the latch recess and the interior wall.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/319,891, filed Jan. 21, 2003. 
    
    
     BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The invention relates to a roll-up door assembly of the type commonly used in a trailer for a semi-tractor or a truck. In one of its aspects, the invention relates to a lightweight roll-up door comprising multiple, longitudinally-oriented extruded panels having a longitudinal hinge axis that can be assembled transversely relative to the hinge axis. In another of its aspects, the invention relates to an extruded panel for a roll-up door, which includes an integrated mounting and guide system for positioning and attaching door hardware to the panel. 
     2. Description of the Related Art 
     Trailers for semi-tractors and delivery trucks have long used roll-up doors to control access through a rear opening of the trailer. Roll-up doors are often preferred over the vertically-hinged, outwardly swinging doors because the roll-up doors operate within the physical space of the trailer and do not require space beyond the trailer. The roll-up door is moveable between an opened and a closed position while being maintained entirely within the trailer whereas the swinging doors require room along the sides of the trailer to swing from the closed to the opened position. If the trailers are to be parked side-by-side, the swinging doors must be opened prior to parking the trailer or the trailers must be parked far enough apart to permit the doors to swing from the closed to the opened position, both of which are an inconvenience to the operator. 
     Roll-up doors typically comprise multiple panels, stacked one atop the other. The adjacent edges are hingedly connected together to form the entire door. The hinges are normally located on or near the adjacent longitudinal edges of the panels. There are generally two main types of hinged structures that can be categorized by the direction in which the panels must be assembled relative to the longitudinal axis of the panels. One hinge structure requires that the panels be slid laterally (in the same direction as the longitudinal axis) to hingedly couple/uncouple the panels. Another structure requires that the panels be moved to transversely or perpendicular to the longitudinal edge to hingedly couple/uncouple the panels. 
     Each panel usually includes a roller assembly comprising an axle that rotatably supports a roller or wheel. The axle is mounted to the panel, directly or through the hinge assembly. The wheel is received within a track mounted within the interior of the trailer. As the door is raised from the lowered or closed position to the raised or opened position, the panels move within the tracks and rotate relative to each other as needed about their respective hinges. The panels are constrained in their movement by the receipt of the rollers within the track. Thus, the maximum angle of rotation between any two panels can be controlled by the arc of the track. 
     Roll-up doors have several known problems or disadvantages. Many roll-up doors have panels that are made entirely of solid material, such as wood. The resulting door is exceptionally heavy and requires counter-balancing springs to lift and close the door. The counter-balancing springs reduce the usable volume of the trailer, which is highly undesirable given the great value placed upon usable volume for a truck or trailer. 
     Attempts to address this problem have focused on using lighter weight materials, especially extruded plastics. The resulting extruded panels are relative light in weight, but they often require special or complex hinge systems and special structural stiffening to accommodate the mounting of the roll-up door hardware such as handles and latch assemblies. 
     Many roll-up doors are often time-consuming to repair. When a roll-up door is damaged, usually the repair is affected by merely replacing one of the multiple panels. Unfortunately, most roll-up doors have a panel and hinge configuration that requires the removal of multiple or all of the panels to replace the damaged panel. Panels that have hinges that require the lateral sliding of the panels for assembly further exacerbate the replacement of a single panel in that all of the panels preceding the damaged panel must be removed from the tracks before the damaged panel can be laterally slid and uncoupled from the adjacent panels. 
     Solutions to this problem have tended to focus on hinge structures that permit the transverse addition/removal of the panels. Most of the current solutions rely on a relatively complex hinge construction to permit the transverse removal of the hinge as part of the transverse removal of the panel. 
     SUMMARY OF INVENTION 
     According to the invention, a light weight roll-up door for use in closing a rear opening of a truck or trailer comprises multiple elongated panels and a hinge assembly that is snap fit to the panels at the upper and lower edges thereof. Each panel has a generally rectangular periphery and is formed by extrusion of a light weight material to form inner and outer opposing surfaces spaced from each other and at least one elongated groove integrally formed in the inner surfaces at the edge portions thereof. The snap hinge assemblies have integral snap fit fasteners that are releasably received in the elongated grooves of the panels. Outer complementary arcuate portions on the panel upper and lower edges fill a gap at the facing edges of the panels as the panels rotate about the hinge. 
     In one embodiment of the invention, the snap fit fasteners comprise compressible fasteners. The compressible fastener comprises two spaced resilient fingers defining a gap therebetween and the fastener is compressed by deflecting at least one of the fingers into the gap at the facing edges of the panels. Typically, the outer cross-sectional periphery of the fastener generally conforms to the cross-sectional shape of the groove. 
     The hinge assembly preferably comprises multiple hinge elements, with each hinge element having its own first and second hinge plates and hinge. Further, one of the hinge elements includes an axle seat. The axle seat is a generally circular tubular portion the interior of which forms a socket. A wheel assembly comprising an axle and a wheel rotatably mounted to the axle, which is received within the axle seat. 
     The roll-up door according to the invention is used in combination with a trailer with an opening for selectively closing the opening in the trailer that is defined in part by a bottom wall of the trailer. The roll-up door has multiple elongated panels which are connected together at upper and lower sides in vertically oriented relationship. The hinge assembly rotatably couples adjacent panels. One of the panels is a bottom panel whose lower side is adjacent the trailer bottom wall when the roll-up door is mounted to the trailer and in a closed position. A latch assembly is mounted to the bottom panel and is adapted to be selectively coupled to the trailer to lock the roll-up door in the closed position. According to one embodiment of the invention, the bottom panel is an extrusion having a predominately hollow interior between and exterior and interior walls and comprises a latch recess in the exterior wall and multiple mounting supports disposed within the hollow interior and extending between the latch recess and the interior wall. The latch assembly is received in the latch recess. 
     The latch recess is preferably located on the exterior wall such that placement of the latch assembly therein positions the latch assembly in proper vertical position to selectively couple with the trailer. In one embodiment the latch assembly comprises a mounting plate and the latch recess has a height substantially equal to the height of the mounting plate to thereby fix the vertical position of the latch assembly when it is positioned within the latch recess. In a preferred embodiment of the invention, an alignment indicia is positioned on the front wall of the panel for use in laterally aligning the latch assembly relative to the bottom panel. Typically, the mounting supports comprise extruded walls extending between the latch recess and the interior wall and are arranged in spaced pairs and defining a channel therebetween in which a fastener can be received. Preferably, the spacing of the walls is such that a head of a mechanical fastener used to fasten the latch assembly to the bottom panel will overly at least a portion of at least one of the walls of a pair. Typically, the spacing of the walls is such that it is less than the outer diameter of a threaded fastener. 
     In a further embodiment of the invention, a backing plate recess is formed on the interior of the panel and at least part of the backing plate recess is opposite a portion of the latch recess. Further, the mounting supports extend between the latch recess and the backing plate recess. 
     In yet another embodiment of the invention, a reflector recess is formed in the exterior wall, located above the latch recess and of a size to receive therein a conspicuity reflector. 
     In accordance with another embodiment of the invention, a roll-up door for selectively closing an opening in a trailer is defined in part by a bottom wall of the trailer and the roll-up door comprises multiple elongated panels having opposing interior and exterior walls and an upper and lower sides connecting an upper portion of the walls and a lower portion of the walls, respectively. The panels are stacked in an upper side to lower side orientation, a hinge rotatably couples adjacent panels, and one of the panels is a bottom panel whose lower side is adjacent the trailer bottom wall when the roll-up door is mounted to the trailer and in a closed position. A latch assembly is mounted to the bottom panel and is adapted to be selectively coupled to the trailer to lock the roll-up door in the closed position. The bottom panel is extruded and has a predominately hollow interior between exterior and interior walls. A reflector recess is formed in the exterior wall, located near a bottom portion of the panel and of a size to receive therein a conspicuity reflector. 
     The bottom panel further has a latch recess in the exterior thereof at the bottom portion thereof and the latch assembly is mounted in the latch recess. The reflector recess is formed above the latch recess. 
     In one embodiment of the invention, a roller is adapted to mount into a rail at the side of the truck or trailer opening and a wear resistant axle is received in a socket in the panels. A socket made of a wear resistant material is attached to each of the lateral sides of the panels and receives an axle of the wheel assembly therein. In one embodiment of the invention, the sockets are formed of a wear-resistant metal. In another embodiment of the invention, the sockets are formed of a tough, wear-resistant plastic, such as nylon or polypropylene. 
     In a preferred embodiment of the invention, the sockets further include a mounting plate through which the sockets are mounted to the panels and the sockets are integrally formed with the mounting plates. Typically, the axles are made of metal. 
     The panels are extruded and have open ends. The panels are preferably formed of a rigid plastic material or a lightweight metal. Typically, end caps close the open ends of the panels and include mounting tabs that fit within open ends of the panels. The end caps are made of an injected molded plastic. 
     The mounting plates are fastened to the panels with mechanical fasteners that extend through the exterior and interior walls, through the mounting tabs of the end plates and through the socket mounting plate. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a rear perspective view of a trailer incorporating a roll-up door according to the invention, with the roll-up door comprising multiple, hingedly-coupled panels moveably mounted within a track. 
         FIG. 2  is a perspective view of a first embodiment roll-up door according to the invention and comprising a bottom panel, intermediate panels, and a top panel, which are hingedly coupled by hinge assemblies. 
         FIG. 3  is an exploded partial perspective assembly view showing a hingedly coupled lower panel and upper panel and the assembly of the seal assembly, axle bracket assembly, and end caps to the panels. 
         FIG. 4  is an assembled partial perspective view of the door elements of  FIG. 3  assembled. 
         FIG. 5  is an end view of the bottom panel of  FIG. 3  and illustrating an upper side structure forming a portion of the hinge. 
         FIG. 6  is an end view of an intermediate panel of  FIG. 3  and illustrating a lower side structure including first and second channels for connecting a hinge coupler. 
         FIG. 7  is a detail drawing of the cross section for the first channel used in connecting the hinge coupler to the intermediate panel. 
         FIG. 8  is a detail drawing of the cross section for the second channel used in connecting the hinge coupler to the intermediate panel. 
         FIG. 9  is a end view of the top panel for the first embodiment incorporating the same lower end structure as the intermediate panel. 
         FIG. 10  is a side view of the top cap mounted to a top panel. 
         FIG. 11  is a side view of a top cap for the top panel. 
         FIG. 12  is a end view of the hinge coupler for the first embodiment and which has first and second connectors that are received in the second and first channels, respectively, to mount the hinge coupler to a panel and a hook forming part of the hinge between adjacent panels. 
         FIG. 13  is a detail of the first connector of the hinge coupler for coupling the hinge coupler to the second channel. 
         FIG. 14  is a detail of the second connector of the hinge coupler for coupling the hinge coupler to the first channel. 
         FIG. 15  is a detail of the hook of the hinge coupler for forming a portion of a hinge between adjacent panels. 
         FIG. 16  is a side view of two intermediate panels hingedly connected by the hinge coupler. 
         FIG. 17  is a side view similar to  FIG. 16  with the intermediate panels partially disassembled. 
         FIG. 18  is an exploded side assembly view of the bottom panel of the first embodiment and the corresponding door hardware comprising a latch assembly, a seal assembly, and an axle mounting bracket. 
         FIG. 19  is a side assembly similar to  FIG. 18  showing the assembled bottom panel, latch assembly and axle mounting bracket. 
         FIG. 20  is an exploded side view of the bottom panel, latch assembly, and a seal assembly of the roll-up door shown in  FIG. 1  for sealing a lower side of the bottom panel relative to the truck or trailer. 
         FIG. 21  is a side view of a bottom panel for a second embodiment of the invention and illustrating an upper side structure forming a portion of the hinge. 
         FIG. 22  is a side view of a top panel for the second embodiment of the invention and incorporating the same upper side structure as the bottom panel and having a new lower side structure. 
         FIG. 23  is an enlarged view of a lower side structure of the bottom panel for connecting a hinge element to complete the hinge for the second embodiment. 
         FIG. 24  is a side view of an intermediate panel for the second embodiment incorporating the same upper end structure as the bottom panel and the same lower end structure as the top panel and additionally shows a hinge coupler attached to the lower end structure. 
         FIG. 25  is an enlarged side view of the hinge coupler of  FIG. 24 . 
         FIG. 26  is a side view of multiple intermediate panels of the second embodiment coupled together and arranged in a coplanar or closed orientation. 
         FIG. 27  is a side view similar to  FIG. 26  except that at least one of the panels is rotated relative to the adjacent panel to illustrate the panels in an opened position. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a truck or semi-trailer  10  incorporates a roll-up door  12  according to the invention. The trailer  10  is of a well-known design and comprises opposing sidewalls  14 ,  16 , which are connected at their upper ends by a top wall  18  and at their lower ends by a bottom wall  20 . The top wall  18 , bottom wall  20 , and sidewalls  14 ,  16  collectively define a rear opening  22  that is bounded by a peripheral frame  24 . The roll-up door  12  is mounted to the trailer  10  such that the roll-up door  12  closes the rear opening  22  when the roll-up door is in the lowered position as illustrated in  FIG. 1 . A latch assembly  26  is provided for locking the roll-up door  12  in the closed position. 
     Referring to  FIG. 2 , the roll-up door  12  is shown with the trailer  10 , with the top wall  18 , bottom wall  20 , and sidewalls  14 ,  16  removed for clarity. The roll-up door  12  comprises multiple panels  530  that are hingedly connected by hinge assemblies  532 . Roller assemblies  534  are carried by the hinge assemblies  532  on each side of the panels  530  and movably couple the panels  530  to a pair of tracks  36 . 
     The tracks  36  are of a traditional design and have a stretched C-shaped cross-section that defines a channel in which the roller assemblies  34  are received. The tracks  36  are typically mounted to the sidewalls  14 ,  16 , respectively. Each of the tracks  36  can be conceptually divided into a vertical portion  40  and a horizontal portion  42 , which are connected by a curved or turn portion  44 . The vertical portion  40  is normally located adjacent to the peripheral frame  24  of the trailer  10  and the horizontal portion  42  is normally located adjacent the top wall  18  of the trailer. In this manner, the multiple, hingedly-connected panels  530  can be moved from the closed or lowered position as seen in  FIG. 1 , where almost all of the panels are located in the vertical portion  40  of the tracks  36 , to an opened or raised position, where almost all of the panels are received in the horizontal portion  42  of the tracks  36 . The curved portion  44  aids in transitioning the multiple, hingedly-connected panels  530  from the vertical portion to the horizontal portion. 
     Referring to  FIGS. 2 and 3 , in the preferred embodiment, there are three different types of panels  530  used to form a complete roll-up door  12  and include a bottom panel  580 , intermediate panel  582 , and top panel  584 . A complete roll-up door  12  will include a single bottom panel  580  and a single top panel  584  between which are disposed multiple intermediate panels  582 . The bottom panel  580  is the lower-most panel of the roll-up door  12  and the top panel is the uppermost panel of the roll-up door  12  as their names connote. 
     The bottom panel  580 , intermediate panel  582 , and top panel  584  all have the same general structure but do vary in specific structure, mostly at upper and lower sides because of different functional requirements associated with their physical position within the roll-up door  12 . For example, the bottom panel  580  provides for mounting the latch assembly  26  along with aiding and sealing the roll-up door  12  to the trailer  10 . 
     Each of the panels is hingedly connected by the hinge assembly  32 , which comprises a hook  600  and a hinge coupler  660 . The hook  600  is integrally formed on an upper edge of the bottom panel  580  and intermediate panels  582 . The hinge coupler is mounted to the lower edge of the intermediate panels  582  and the top panel  584 . The hinge coupler  660  pivotally mates with the hook  600  to hingedly couple the adjacent panels. 
     A wheel assembly  534  comprising a mounting plate  663  with a shaft sleeve  665  and a wheel  78  rotatably mounted on a shaft  76  connects each panel to the rails. The shaft  76  is slidably received within the shaft sleeve to mount the wheel to the panel through the mounting plate  663 . Fasteners  775  secure the mounting plate to the corresponding panel. 
     End caps  700 ,  702 , and  704  are mounted to the ends of each panel to close off the exterior as is best seen in  FIG. 4 . The end caps  700 ,  702 , and  704  are preferably shaped such that they are slidably mounted within their corresponding panel  80 ,  82 , and  84 , respectively. The end caps  700 ,  702  and  704  are preferably made of an injected molded plastic such as polypropylene. 
     A seal assembly  532  is mounted to the lower edge of the lower panel  80 . The seal assembly  532  aids in sealing the bottom of the door with the trailer frame. 
     Looking at the details of the roll-up door,  FIG. 5  illustrates the details of the bottom panel  580 , which comprises an upper side  562  and lower side  564 , which connect outer wall  556  and inner wall  558  to form the basic panel structure. Strengthening ribs  592  extend between the outer and inner walls  556 ,  558 . The ribs  592  are arranged in pairs to form fastener supports  594 . 
     A latch assembly channel  585  and a reflector channel  587  are formed in the outer wall  556 . A backing plate recess  586  is formed in the inner wall  558 . The channels  585 ,  587  and recess  586  perform the same functions as the first two embodiments. Optional projections  589  that partially overlie the reflector channel  587  are provided on the outer wall  556 . The optional projections permit the snap-in mounting of a reflector in the channel. 
     The projection  600  comprises a back  602  and a generally flat face  604  overlying a curl or recess portion  605 . The back  602  terminates inwardly of the outer wall  656  to form a stop  606 . The transition between the face  604  and the curl  605  forms a depending flange  608 . The curl  605  comprises an angled portion  610  that transitions into a vertically oriented portion  612 . The projection  600  functionally forms a hinge plate. The depending flange  608  forms part of the hinge. 
     Referring to  FIG. 6 , the intermediate panel  582  also comprises an upper side  552 ′ and lower side  554 ′, which connect outer wall  556 ′ and inner wall  558 ′ to form the basic panel structure. Strengthening ribs  592 ′ extend between the outer and inner walls  556 ′,  558 ′. 
     The intermediate panel further comprises the same projection  600 ′ on the upper side  552 ′ as the projection  600 . Therefore the projection  600 ′ will not be described further. Parts of the projection  600 ′ corresponding to the projection  600  are identified with the same numeral followed by the prime ′ suffix. 
     Referring to  FIGS. 6–8 , the lower end  554 ′ of the intermediate panel  582  comprises a first channel  620  opening onto the inner wall  558 , with a lip  622  extending into the channel  620 . A catch  624  extends into the channel  620  on a side opposite the lip  622 . The space between the lip  622  and the catch  624  defines an opening or throat for the channel. 
     A second channel  640  is formed in the outer wall  556 ′ and comprises an arcuate side  641 , an angled bottom  642 , and a short arcuate side  643  opposing the arcuate side  641 . The gap between the outer wall edges of the arcuate side  641  and short arcuate side  643  define an opening or throat to the second channel  640 . The portion of the inner wall  558 ′ transitioning between the first channel  620  and the second channel  640  comprises a step  650  and a riser  652 . 
     Referring to  FIG. 9 , the top panel  584  is illustrated in detail. The top panel  584  is similar to the bottom and intermediate panels  580 ,  582  in that it has top, bottom, outer and inner sides  552 ″,  554 ″,  556 ″, and  558 ″, with strengthening ribs  592 ″ extending between the inner and outer sides  558 ″ and  556 ″. The top panel does not include a projection  600  as do the bottom panel  580  and the intermediate panel  582 . Instead, the upper end  552  of the top panel  584  terminates in a flat surface. 
     The bottom side  554 ″ of the top panel  584  does include first and second channels  620 ′ and  640 ′ that are identical to channels  620  and  640 . Therefore, the structure of the channels  620 ′ and  640 ′ will not be described in further detail. 
       FIGS. 10 and 11  illustrate a top cap assembly  730  for use with the top panel  584  when it is necessary to remove an upper portion of the top panel  584  to adjust the overall door height to correspond to a particular door opening height. The need to alter the top panel  584  height arises because the panels  580 ,  582 , and  584  are preferably extruded with a predetermined height. It is anticipated that the height of the vehicle opening and the available interior vehicle space for receiving the door in the raised position will not permit a door comprised of all full-height panels. In such a situation, one of the panels may need to be shortened in height by cutting away a portion of the panel. It is preferred to cut away the top portion of the top panel since it is not connected to any other panel or forms a seal with respect to the opening. 
     The top cap assembly  730  comprises a top cap  732  from which extends a seal  734 . The top cap  732  comprises opposing sidewalls  736  whose upper ends are connected by a top wall  738 . A guide  740  is located between the sidewalls  736  and extends away from the top wall  738  to form opposing channels  742 . The channels  742  are preferably of a width greater than the thickness of the inner wall  558  and the outer wall  556 , respectively, of the top panel to permit the top cap to be slidably mounted onto the cut top of the top panel  584  such that the guide  740  is received within the hollow interior between the inner wall  558  and the outer wall  556  while the sidewalls  736  are received on the exterior of the inner wall  558  and outer wall  556 , respectively. Fasteners in the form of the previously described bolts  775  and corresponding nuts  777  secure the top cap  732  to the top panel  584  as shown in  FIG. 43 . 
     The seal  734  preferably extends laterally away from the top cap  732  and comprises an increased thickness portion  744  from which extends a tapering portion  746 . It is preferred that the seal  734  be flexible to enhance the contact between the seal  734  and the door frame. 
     The top cap assembly  730  is preferably co-extruded such that the top cap  732  is made from one type of material and the seal  734  is made from another type of material. The top cap  732  is preferably made from the same material as the top panel  584 . The seal  734  is made from a lower durometer material to increase its flexibility. 
     Referring to  FIG. 12  a hinge coupler  660  is shown and comprises first and second connectors  662  and  664  for connecting the hinge coupler  660  to the lower side of a panel. A hinge channel  668  is integrally formed with the hinge coupler  660 . The hinge channel  668  cooperates with one of the projections  600 ,  600 ′ to hingedly connect the upper side of one panel to the lower side  454  of another panel. 
     Referring to  FIGS. 12 and 13 , the first connector  662  comprises a head  670  connected by a neck  672  to the main portion of the hinge coupler  660 . The head has an irregular shape defined by an arcuate surface  673 , planar surface  674 , and a short arcuate surface  675 , which correspond respectively to the arcuate side, angled bottom, and short side of the second channel. The head  670  is sized such that the first connector  662  is received within the second channel  640  by inserting the head through the throat of the channel  640  when the head  670  is oriented relative to the throat at an angle between 20 and 45 degrees. Once the head  670  is inserted, the hinge coupler  660  can be rotated such that the arcuate surface  673 , planar surface  674 , and short surface  675  are adjacent the corresponding arcuate side, angled bottom, and short side of the second channel. The end of the short side of the second channel can also abut the neck  672  to limit the relative rotation of the hinge coupler and the panel to which it is mounted. 
     Referring to  FIGS. 12 and 14 , the second connector  664  also comprises a neck  678  that transitions into a head  680  having an asymmetrical cross-section. One side of the head  680  comprises an angled surface  682  that transitions into a laterally extending shoulder  684 . A locking finger  688  extends from the other side of the head  680  and comprises reduced thickness area at the junction with the head to form a living hinge  686  about which the locking finger can rotate. The locking finger  688  preferable forms an acute interior angle with the head  680 . 
     The second connector  664  in combination with the first connector  662  mounts the hinge coupler  660  to the lower side of a panel. Where the first connector  662  mounts to the outer wall of the panel, the second connector  664  mounts to the inner wall of the panel. The second connector  664  mounts to the inner wall by inserting the head  680  into the first channel  620 . When the head  680  is inserted, the shoulder  684  of the bead  680  seats behind the lip of the first channel and the end of the finger  688  seats against the catch of the first channel. It is preferred that the finger  688  will be made of an inherently resilient material such that the finger  688  will naturally move into a seated position behind the catch. However, it is within the scope of the invention for the finger  688  to be manually moved into the seated position by the person assembling the door. 
     The resilient finger  688  functions as a lock and holds the second connector  664  within the first channel  620 . The resilient finger  688  must be deflected into the channel  620  to provide sufficient clearance for the second connector  664  to be removed through the open end of the first channel  620 . Once a portion of the second connector  664  has been removed from the first channel  620 , the remainder of the second connector  664  can be “unzipped” by pulling outwardly on the first connector  662  which will continue to deflect the resilient finger  688  as the second connector  664  is removed. 
     Referring to  FIGS. 12 and 15 , the hinge channel  368  comprises an arcuate surface  690  that transitions through a radius  692  into a relatively straight portion  694 . The straight portion  694  terminates in a hook  696 . The hinge channel  668  has a mouth extending between the arcuate surface  690  and the hook  696 . 
       FIG. 16  illustrates the hinge coupler  660  connecting the lower side  554 ′ of an intermediate panel  582  to the upper side  552 ′ of an adjacent intermediate panel  582 . When coupled, the head  670  of the first connector  662  is received within the second channel  640  such that the arcuate surface  673  and short surface  675  of the head  670  abut the arcuate side  641  and the short side  643  of the second channel  640 , respectively. The shoulder  682  of the second connector  664  as seated behind the lip  622  of the first channel  620  and the end of the finger  688  is seated against the catch  624 . 
       FIG. 17  illustrates a partial disassembly of the intermediate panels  582  of  FIG. 14 . To disassemble the intermediate panels  582 , the second connector  664  is removed from the first channel  620  by peeling the second connector  664  from the first channel. To initiate the peeling of the second connector, it is preferred that the person disassembling the panels rotate the finger  688  about the hinge  686  toward the head in a counter-clockwise direction as seen in  FIG. 1 . The rotation of the finger is continued until the head  680  of the second connector can be pulled from the first channel  620 . The continued pulling on the head  680  or neck  678  of the second connector  664  will remove both the head  680  and the finger  688  from the first channel  620 . 
     Depending on the type of material used to form the finger  688  and the head  680  and/or the tolerances between the head  680 , finger  688  and the first channel  620 , it may be necessary to continuously, actively unseat the finger  688  as the head  680  is pulled from the first channel  620 . 
       FIGS. 18 and 19  illustrate the mounting of door hardware to the lower panel. The hardware includes latch assembly  26  and a seal assembly  460 , with  FIG. 18  showing latch and seal assemblies  26  and  460  in an exploded and then assembled. 
     Referring to  FIG. 3  generally and  FIGS. 18 and 19  specifically, the seal assembly  460  comprises a seal  630 , backing plate  632 , and axle mounting bracket  534 . The seal  530  comprises a main body  536  in which are formed opposing slots  538  and from which extend the multiple longitudinal fingers or seals  540 . The outermost finger  540  extends further from the body  536  and the other fingers  540 . 
     The backing plate  532  comprises a vertical leg or face  542  from which laterally extends a seal mount  544 . The seal mount  544  comprises an upper wall  545  from which extend opposing L-shaped legs  547 , which in combination with the upper wall  545  define a T-shaped longitudinal opening  549 . The T-shaped opening  549  is sized to longitudinally slidably receive the body  536  of the seal assembly  530  such that the legs  547  of the seal mount  544  are received within the opposing slots  538  of the body  536 . 
     An advantage of the seal assembly  530  is that the body  536  is sized and attached to the seal mount such that forces acting on the seal assembly associated with the closing of the door are predominately carried by the central portion of body  536  and not the seals  540 . The central portion of the body  536  is the cross-sectional portion located interiorially of the slots  538  and fingers  540  and extending the height of the seal assembly  530 . 
     Referring to  FIGS. 18 and 19  specifically and  FIGS. 2 and 4  generally, the axle mounting bracket  534  comprises a metal mounting plate  663  and a tubular, metal mounting seat  665  whose interior defines a socket  667  for receiving the shaft of the wheel assembly. The mounting plate  663  can be made of metal or of a tough wear resistant plastic. Thus, the socket  667  is significantly more wear resistant that the extruded panels  580 ,  582  and  584 . 
     Fasteners in the form of bolts  775  and nuts  777  secure the mounting plate  663  to the inner wall  558  of the intermediate panel  582 . The bolt  775  pass through aligned openings  546 ,  552  and the lower panel to secure the backing plate  542  and the axle mounting bracket  534  to the panel. Similar fasteners are also used to secure the latch assembly  26  to the lower panel. 
     The bolts  775  preferably include a knurled portion near their head to prevent the rotation of the bolt as the nut is threaded onto the bolt. Other suitable bolt structures or features can also be used in place of the knurled portion to prevent the bolt from rotating when the nut is tightened. For example, the bolt can have a square cross section and the openings in either or both the panel and mounting plate can have a corresponding square cross section. 
     The axle seat  665  extends away from a plane defined by the mounting plate  663 . An axle seat recess  669  and a backing plate opening  671 , both sized to laterally receive the axle seat  665 , are formed in the exterior of the inner wall  558  and in the backing plate  542 . The backing plate opening  671  and the axle seat recess  669  permits the flush mounting of the axle seat assembly  661  to the inner wall  558  of the intermediate panel  582  while locating the centerline for the axle seat, which coincides with the axle rotational axis, closer to the center of the door. 
     The axle mounting bracket  534  mounts the wheel assembly to each of the intermediate and top panels. The metal axle seat of the axle mounting bracket provides greater wear. Also, the axle mounting brackets improve the ease of laterally assembling and disassembling the panels since the wheel assembles can be removed independently of the hinge coupler. 
       FIGS. 3 and 4  illustrate the mounting of the axle mounting bracket  534  to an intermediate panel  582  and a bottom panel  580 , with both panels being connected by the hinge coupler  660 . As with the bottom panel  580 , the intermediate panel  582  also requires an axle seat recess  669 ′ sized to receive the axle seat  665 . Unlike the bottom panel  580 , the axle seat recess  669 ′ is formed in the exterior of the hinge coupler  660  at any side edge thereof, instead of in the lower edge of the intermediate panel  582 . The axle seat recess  669 ′ permits the flush mounting of the axle seat assembly  661  to the inner wall  558  of the intermediate panel  582 . Additionally, the axle seat recess  669  permits the centerline of the axle seat  665 , what ultimately formed the centerline for the axle of the wheel assembly, to be closer to the hinge axis of the adjacent panels, which is located at the junction of the depending flange  608 ′ of the hook  600 ′ and the hook  696  of the hinge coupler  660 . 
     The bolts  775  and nuts  777  are used to mount the axle mounting bracket  534  to the intermediate panel  582  in the same manner as to the lower panel  580 . The only difference is that the bolts must also pass through the hinge coupler  660 . 
     Since it is preferred that the panels and the hinge coupler are extruded, it is anticipated that the axle seat recesses  669  or  669 ′ will be formed in the corresponding panel or hinge coupler after the panel or hinge coupler  660  is extruded. To aid in the creation of the axle seat recess  669 , the bottom panel  580  and hinge coupler  660  are extruded with a longitudinal recess  771  and  771 ′ ( FIGS. 5 and 10 ). Thus, a lesser amount of material needs to be removed from either the panel or the hinge coupler to form the axle seat recess  669  or  669 ′. The addition of the longitudinal recess  671  or  671 ′ has the further benefit of reducing the amount of material needed to extrude the bottom panel  580  or hinge coupler  660 . 
     Referring to  FIGS. 2 and 3  it is preferred that an end caps  700 , 702 , and  703  are used for closing the end of the bottom panel  580 , intermediate panel  582 , and top panel  584 , respectively. The end caps  700 , 702 ,  703  comprise an end plate  704 , 706 ,  707  from which laterally extend a series of mounting tabs  708 ,  710 , and  711 . 
     The end plates  704 , 706 , and  707  are complementary in shape to the side cross section of the bottom panel  580  and intermediate panel  582 , respectively, such that when the mounting tabs  708 , 710 ,  711  are received within the interior of the corresponding panel  580 ,  582 , the end plates  704 , 706 ,  707  close off and/or seal the opening and of the corresponding panel. 
     Each of the end plates includes a notch  712 , 714 ,  715  that aligns with the corresponding recess  671 ,  671 ′,  671 ″ to permit the passage of the axle for the wheel assembly. The end plate  706  also includes a stop portion  718  located between the notch  714 . The stop portion  718  is sized to overlie the mated hook  600  and hinge coupler  660  to prevent the relative lateral movement of the bottom panel  580  and the intermediate panel  582 . 
     The mounting tabs  708 ,  710 ,  711  can be of any number and shape. Preferably, the number and shape of the mounting tabs  708 , 710 ,  711  correspond to the interstitial spaces defined by the outer wall  556 , inner wall  558 , and the corresponding structural supports  592  and  592 ′,  592 ″. 
     The end caps  700 , 702 ,  703  perform several functions. Since the end caps seal the otherwise opened and of the panels, the end caps prevent moisture and dirt from collecting inside the panels. The end caps also prevent the door from racking since the individual panels are prevented from moving laterally relative to each other by the stop portion. 
     The extruded panel roll-up door according to the invention is advantageous over current wood panel roll-up doors because of the substantially reduced weight of the extruded panels. The reduced panel weight also permits weight reduction in other areas of the roll-up door. For example, a smaller and lighter counterbalancing spring is needed. For a semi-trailer with a width of 15 inches and height between 75 and 114 inches door opening, the overall weight difference between a roll-up door with extruded panels and one with wooden panels is approximately 40 lbs, permitting an equal weight of increased cargo to be carried by the trailer on each delivery. Over the life of the trailer, the additional load carrying capacity of a trailer with an extruded panel door translates into substantial increased profitability. The extruded panels are also much less susceptible to impact damage than wood panels, which reduces the need for panel replacement, resulting is a reduced operating cost for the extruded panels. 
       FIGS. 20–27  illustrate a second embodiment panel design for the roll-up door  12 . The second embodiment panel design includes a bottom panel  280  ( FIGS. 20 and 21 ), multiple intermediate panels  282  ( FIG. 29 ), and a top panel  284  configuration ( FIG. 22 ) similar to that of the first embodiment. 
     The main distinction between the second embodiment panel design and the first embodiment lies in how and where the hinge coupler connects to the intermediate and upper panels and an alternative seal assembly is shown. All other aspects of the two embodiments are substantially identical. Therefore, only the major differences between the first and second embodiments will be described, with it being understood that the description of the features for the first embodiment applies to similar features of the second embodiment. 
     Referring to  FIGS. 20 and 21 , the second embodiment bottom panel  280  comprises a projection  300  having a back  302  and a generally flat face  304  overlying a curl or recess portion  305 . The back  302  terminates inwardly of the outer wall  456  to form a stop  306 . The transition between the face  304  and the curl  305  forms a depending flange  308 . The curl  305  comprises an angled portion  310  that transitions into a vertically oriented portion  312 . The projection  300  functionally forms a hinge plate. The depending flange  308  forms part of the hinge. 
     A hardware recess  485  and reflector recess  487  are formed in the outer wall  456  and a seal recess  486  is formed in the inner wall  458 . The hardware recess receives the latch assembly  26  and the seal recess  486  receives the seal assembly  160 . 
     Referring to  FIGS. 22 and 23 , the second embodiment top panel  284  does not include a projection  300  formed at the upper end thereof. Instead, the upper end  452  of the top panel  284  terminates in a flat surface as does the top panel of the first embodiment. The upper end of the second embodiment can be cut in the same manner as described for the first embodiment. 
     The lower end  454  of the top panel  284  comprises a first channel  320  opening onto the inner side  458 . A lip  322  extends into the channel  320 . A resilient locking finger  324  extends into the channel  320  on a side opposite the lip  322 . The resilient locking finger  324  includes a stem  326  that terminates in a head  328 . 
     A second channel  340  is formed near the outer side  456 , but still opens toward the inner side  458 . The channel  340  comprises a neck  342  that transitions into a head  346 , which has a larger cross-sectional width than the neck  342 . The portion of the inner side  458  transitioning between the first channel  320  and the second channel  340  comprises a step  350  and a riser  352 . The transition from the second channel  340  to the outer side  456  also comprises the steps  352  and a riser  350 . 
     Referring to  FIGS. 24 , the second embodiment intermediate panel comprises the same projection  300 ′ on the upper side  452  as the projection  300  of the bottom panel and the same structure on the lower side  454  as the top panel  284 . Therefore they will not be described in detail. 
     Referring to  FIGS. 24  a hinge coupler  360  is shown mounted to the lower side  454  of the intermediate panel and cooperates with the projection  300  of another panel to hingedly couple together the panels.  FIGS. 24 and 25  further illustrate the features of the hinge coupler  360 , which includes first and second connectors  362  and  364  for connecting the hinge coupler  360  to the lower side  454  of the panel. An axle seat  365  is integrally formed with the connectors  362 ,  364  and defines a shaft opening  367  for receiving the axle shaft of the roller assembly. A hinge channel  368  is integrally formed with the hinge coupler  360 . The hinge channel  368  cooperates with the projection  300  to hingedly connect the upper side  452  of one panel to the lower side  454  of another panel. 
     The first connector  362  comprises opposing spring fingers  370 ,  372 , separated by a gap or channel  374  and forming an outer periphery that transitions from a neck to a head. The first connector  362  is received within the second channel  340  by inserting the head into the neck  342  of the channel  340 , which deflects the spring fingers  370 ,  372  inwardly, until the head extends beyond the neck  342  of the channel  340  where the spring fingers  370 ,  372  can then return to their original position with the head of the first connector  362  received within the head of the channel  340 . 
     The second connectors  364  also comprises a neck  378  that transitions into a head  380  having an asymmetrical cross-section. One side of the head  380  comprises an angled surface  382  that transitions into a laterally extending shoulder  384 . The other side of the head  380  comprises an angled surface  386  that transitions into a radius  388  that is complementary to the shape of the head  328  for the locking finger  324 . When the second connector  364  is received within the first channel  320 , the shoulder  384  bears against the inner end of the lip  322  and the head  328  of the resilient finger  324  rests within and abuts against the radius  388 . 
     The resilient finger  324  functions as a lock and holds the second connector  364  within the first channel  320 . The resilient finger  324  must be deflected into the channel  320  to provide sufficient clearance for the second connector  364  to be removed through the open end of the first channel  320 . As with the first embodiment, once a portion of the second connector  364  has been removed from the first channel  320 , the remainder of the second connector  364  can be “unzipped” by pulling outwardly on the first connector  362  which will continue to deflect the resilient finger  324  as the second connector  364  is removed. 
     The hinge channel  368  comprises an arcuate surface  390  that transitions through a radius  392  into a relatively straight portion  394 . The straight portion  394  terminates in a hook  396 . The curvature of the hook  396  preferably, but does not need to, corresponds to the curvature of the depending flange  308  for the projection  300 . The hinge channel  368  has a mouth extending between the arcuate surface  390  and the hook  396 . 
     Referring to  FIGS. 26 and 27 , the panels of the second embodiment are shown in the coplanar and rotated positions, respectively. The panels are assembled when they are in a rotated position. To couple the projection  300  to the hinge coupler  360 , the projection  300  is oriented relative to the hinge channel  368  such that the projection  300  can be slidably inserted into the hinge channel  368 . The maximum effective width of the projection  300  is selected such that it can only pass through the mouth of the hinge channel  368  within a predetermined range of angles. The angular range for inserting the projection  300  into the hinge channel  368  is generally selected such that it does not include an angle that the panels will form during normal operation to prevent the inadvertent uncoupling of the panels. 
     Once the projection  300  of one panel is received within the hinge channel  368  of another panel, the depending flange  308  is brought into abutting contact with the inner surface of the hook  396 . The point of abutment between the depending flange  308  and the hook  396  forms the axis of rotation for the connected panels. 
     As with the first embodiment, the arcuate surface  390  of the hinge channel  368  overlies and is in substantially abutting contact with the back  302  of the projection  300  throughout the entire operational rotational range of the panels to thereby prevent the formation of any gap that could pinch the finger of the user. 
     Referring once again to  FIGS. 20 and 21 , the seal assembly  160  comprises an elongated seal  230  that is positioned relative to the bottom panel  280  by backing plate  232 . Multiple wheel assembly mounting brackets  234  secure the backing plate  232  and, thus, the seal  230  to the bottom panel  280 . 
     The seal  230  comprises a main body  236  in which is formed a slot  238 . A pair of depending seals  240  extend away from the main body  236 . A positioning rib  241  extends upwardly away from the main body  236  and is shaped to be received within the seal seat  512  of the bottom panel  280 . 
     The backing plate  232  comprises a vertical leg or face  242  from which extends a mounting flange  244 , which is sized to be received within the slot  238  of the seal  230 . The face  242  has a height such that face  242  is received within the backing plate recess  486  and the positioning rib  241  is held in contact within the seal seat  512 . The face  242  comprises multiple openings  246  through which fasteners  75  can be inserted to secure the backing plate  232  to the bottom panel  280 . Preferably, the openings  246  are located on the face  242  such they align with and correspond to the fastener supports  494 . 
     Wheel assembly brackets  234  are mounted on opposing ends of the lower panel  280 . The wheel assembly brackets  234  included an axle mount  248  that defines an axle socket  250  sized to receive the axle of the wheel assembly. The wheel assembly brackets  234  include openings  252  that correspond with similar openings  246  on the backing plate  232  such that the same fastener  75  can mount the wheel assembly brackets  234  and the backing plate  232  to the bottom panel  280 . The wheel assembly brackets  234  are well-known and have been used a long time in the art. Therefore, they will not be described in greater detail. 
     Another advantage of the design of the bottom panel  280  is that the backing plate recess  486  aids in aligning the backing plate  232  and, thus, the seal  230  with respect to the bottom panel  280  in addition to the alignment of the latch assembly  26  through the latch recess  485 . 
     Further, both the seal assembly  160  and the latch assembly  26  are secured to the bottom panel  280  thorough fasteners  75  that pass-through corresponding openings in the latch assembly  26  in the backing plate  242  and into the channel  486 . The fastener supports  494  provide a force distribution surface to accommodate the compression force associated with the fasteners  75 . If the fasteners  75  are threaded, the ribs  92  of the fastener supports  94  can provide a retaining support into which the threads can be received. Since the fastener supports  94  extend across the entire width of the panel  80 , they provide great flexibility in the location where the fasteners  75  can be used. 
     Reasonable modification and variation are possible within the scope of the forgoing disclosure without departing from scope and spirit of the invention which is defined in the appended claims.