Abstract:
A tonneau cover is arranged to mount on the truck box of a conventional pick up truck for enclosing the box. The cover comprises a pair of panels which are pivotally mounted on respective sides of the box. The panels extend laterally inward such that free ends of the panels engage each other in a closed position. The panels may be pivoted upward and secured in an upward orientation by a pair of rails connected between the free ends of the respective panels in an extended position of the panels. The panels form a pair of side walls in the extended position for supporting large cargo in the box. The rails form a rack in the extended position for supporting additional cargo thereon. A locking device secures the panels in the closed position while a plurality of struts provides additional support to the panels when pivoting the panels between the closed and extended positions.

Description:
This application claims the benefit of priority under 35 U.S.C. 110 from Provisional Application No: 60/780,067 filed Mar. 8 2006. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a tonneau cover for use with conventional pick up trucks having a truck box. 
     BACKGROUND OF THE INVENTION 
     Conventional pick up trucks generally have a truck box on a rearward end for carrying cargo. The use of a tonneau cover which is secured to the truck box is common for enclosing the truck box and for preventing theft of the cargo while the vehicle is unattended. 
     In U.S. Pat. No. 5,110,021 (Dawson) issued May 5, 1992 is disclosed a tonneau cover which includes two separate panels each of which is hinged to a respective side wall of the truck box. Each panel can pivot from a raised position in which it stands generally upwardly from the side wall to a closed position in which it lies generally horizontally across the truck box so that the two panels in the middle and close the open top of the truck box. A pair of rails are provided each mounted on a respective one of the panels and each extending from that panel to the other panel. The rails are spaced so that one is toward the front and one is toward the rear to hold the panels in the raised position and to act as a support for a load over the truck box. This arrangement has achieved no commercial success and the construction shown in the patent is of a simple and schematic nature with little attention to the important details of the mounting of the construction on the truck. box. 
     U.S. Pat. No. 6,224,140 (Hoplock) issued May 1, 2001 discloses a further device of the same general type which gives further details concerning constructions of the device and how it is attached to the side walls of the truck box. Again however this device has achieved no commercial success requiring a significant redesign of the construction. 
     In U.S. Pat. No. 6,340,915 (Hall) issued Jan. 22, 2002 is disclosed an arrangement of this general type and in particular shows a locking arrangement for locking the edge of one panel to the next adjacent panel to hold the panels in closed position. 
     In U.S. Pat. No. 6,254,169 (Arthur) issued Jul. 3, 2001 is disclosed a hinging arrangement for attachment of the panels to the top wall of the truck box. 
     In U.S. Pat. No. 6,598,930 (Tilton) issued Jul. 29, 2003 is disclosed a further arrangement of this type which includes a locking arrangement for locking the edge of one panel relative to the other. 
     In U.S. Pat. No. 6,799,784 (Rios) issued Oct. 5, 2004 is disclosed an arrangement of this type which is particularly concerned with the mounting of the transverse rails to the underside of the panels. 
     None of the above devices has achieved commercial success and it is believed that this is primarily due to failure of the products to apply sufficient attention to the construction and details of the mounting arrangement and the formation of the panels by which the panels can be properly mounted and provide a proper stable structural arrangement which can be carried on the truck box and held in position without deformation or twisting. 
     SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide an improved tonneau cover. 
     According to a first aspect of the present invention there is provided a tonneau cover for a pick up truck having a truck box with a bed, a front and wall and two vertical side walls standing upwardly from the bed, and a rear tail gate pivotal from a raised position extending across the side walls to a horizontal lowered position, the cover for the truck box comprising: 
     a pair of mounting rails each arranged to be mounted on a top surface of a respective side wall of the truck box; 
     a pair of panels each pivotally mounted on a respective one of the mounting rails for pivotal movement between a closed position and a raised open position; 
     each panel in the closed position extending inward from the corresponding mounting rail to a free end such that the free ends of the panels engage each other in the closed position of the panels; 
     each panel in the raised open position extending generally upward from the corresponding mounting rail such that the free ends are spaced apart; 
     two frame elements each mounted between the panels in the raised open position such that the panels are supported in an upright orientation for containing cargo in the truck box, the frame elements being mounted adjacent respective forward and rearward ends of the panels; 
     each mounting rail including a horizontal portion lying on the top surface of the respective side wall, 
     each mounting rail having a row of fasteners adjacent an inner edge for engagement into a corresponding row of first holes in the side wall; 
     each mounting rail having a second row of fasteners, spaced outwardly of the first row, for engagement into a corresponding row of second holes in the side wall. 
     Preferably the fasteners of the first row are fastened from inside the box. 
     Preferably the fasteners of the first row include bolts which have a head captured underneath a top surface of the mounting rail so as to be hidden. 
     Preferably the fasteners of the second row are fastened from on top of the mounting rail. 
     Preferably the fasteners of the second row include butterfly clips on the underside of the side wall. 
     According to a second aspect of the present invention there is provided a tonneau cover for a pick up truck having a truck box with a bed, a front and wall and two vertical side walls standing upwardly from the bed, and a rear tail gate pivotal from a raised position extending across the side walls to a horizontal lowered position, the cover for the truck box comprising: 
     a pair of mounting rails each arranged to be mounted on a top surface of a respective side wall of the truck box; 
     a pair of panels each pivotally mounted on a respective one of the mounting rails for pivotal movement between a closed position and a raised open position; 
     each panel in the closed position extending inward from the corresponding mounting rail to a free end such that the free ends of the panels engage each other in the closed position of the panels; 
     each panel in the raised open position extending generally upward from the corresponding mounting rail such that the free ends are spaced apart; 
     two frame elements each mounted between the panels in the raised open position such that the panels are supported in an upright orientation for containing cargo in the truck box, the frame elements being mounted adjacent respective forward and rearward ends of the panels; 
     each mounting rail including a horizontal portion lying on the top surface of the respective side wall and an inner portion for depending along an inner surface of the respective side wall; 
     each panel having an outer down-turned lip arranged adjacent the inner portion of the respective mounting rail; 
     each mounting rail including a hinge arranged between the outer edge of a respective panel and the inner portion of the respective mounting rail, the hinge comprising two longitudinal connecting members each fastened along a respective one of the outer edge and the inner portion and a continuous flex coupling therebetween such that the hinge acts as a seal between the outer edge and the inner portion. 
     Preferably the hinge extends continuously along the respective panel. 
     Preferably each connecting member includes a top lip and a depending wall with the continuous flex coupling forming a flexible portion connected across the connecting members at the top lip. 
     Preferably each connecting member has a guide flange portion extending therefrom toward the other connecting member. 
     According to a third aspect of the present invention there is provided a tonneau cover for a pick up truck having a truck box with a bed, a front and wall and two vertical side walls standing upwardly from the bed, and a rear tail gate pivotal from a raised position extending across the side walls to a horizontal lowered position, the cover for the truck box comprising: 
     a pair of mounting rails each arranged to be mounted on a top surface of a respective side wall of the truck box; 
     a pair of panels each pivotally mounted on a respective one of the mounting rails for pivotal movement between a closed position and a raised open position; 
     each panel in the closed position extending inward from the corresponding mounting rail to a free end such that the free ends of the panels engage each other in the closed position of the panels; 
     each panel in the raised open position extending generally upward from the corresponding mounting rail such that the free ends are spaced apart; 
     two frame elements each mounted between the panels in the raised open position such that the panels are supported in an upright orientation for containing cargo in the truck box, the frame elements being mounted adjacent respective forward and rearward ends of the panels; 
     each mounting rail including a horizontal portion lying on the top surface of the respective side wall, 
     wherein each panel is molded from an inner layer and an outer layer each formed from a plastics material with the outer layer having a panel portion and a surrounding depending lip and with the inner layer being bonded inside the outer layer; 
     the inner layer being shaped to define a plurality of ribs which extend in a direction transverse to the truck box. 
     Preferably the ribs are recessed to receive the frame element when stored in a retracted position extending longitudinally along the respective panel. 
     Preferably there are provided three recesses in the ribs at positions spaced longitudinally of the panel, where a first recess is arranged to receive an end of the frame element attached to the panel, a second recess is arranged to receive an opposed end of the frame element and a third recess is arranged to receive and end of the frame element of the opposite panel. 
     Preferably inner layer forms a shelf around the outer edge of the panel with a shelf lip of the inner layer at the outer lip of the outer layer to support the shelf for engaging onto a top surface of the truck box. 
     Preferably the shelf at the front and rear ends of the panel is shaped such that a spacing of the shelf from the outer layer increases toward a center of the truck box such that the resting of the shelf on the edge of the truck box acts to hold the panels raised at the center of the truck box and lowered at the side walls of the truck box. 
     Preferably each frame element includes a base plate for mounting the frame element on the respective panel wherein the base plate is trapped between the inner and outer layers. 
     Preferably the layers are formed from ABS. 
     According to a fourth aspect of the present invention there is provided a tonneau cover for a pick up truck having a truck box with a bed, a front and wall and two vertical side walls standing upwardly from the bed, and a rear tail gate pivotal from a raised position extending across the side walls to a horizontal lowered position, the cover for the truck box comprising: 
     a pair of mounting rails each arranged to be mounted on a top surface of a respective side wall of the truck box; 
     a pair of panels each pivotally mounted on a respective one of the mounting rails for pivotal movement between a closed position and a raised open position; 
     each panel in the closed position extending inward from the corresponding mounting rail to a free end such that the free ends of the panels engage each other in the closed position of the panels; 
     each panel in the raised open position extending generally upward from the corresponding mounting rail such that the free ends are spaced apart; 
     two frame elements each mounted between the panels in the raised open position such that the panels are supported in an upright orientation for containing cargo in the truck box, the frame elements being mounted adjacent respective forward and rearward ends of the panels; 
     each mounting rail including a horizontal portion lying on the top surface of the respective side wall; 
     one of the panels having a raised rib along the inner edge for engaging into a recess along the inner edge of the other panel; 
     one of the panels having a plurality of locking toggle members mounted thereon for pivotal movement to engage underneath a bottom edge of the other panel; 
     the toggle members being pivotal by a longitudinal bar extending along the panel. 
     Preferably the locking toggle members are mounted on one of the panels which includes a down-turned lip along its edge at the other panel and wherein the other panel includes a channel along its outer edge with the locking toggle members being arranged to engage underneath a bottom wall of the channel. 
     According to a fifth aspect of the present invention there is provided a tonneau cover for a pick up truck having a truck box with a bed, a front and wall and two vertical side walls standing upwardly from the bed, and a rear tail gate pivotal from a raised position extending across the side walls to a horizontal lowered position, the cover for the truck box comprising: 
     a pair of mounting rails each arranged to be mounted on a top surface of a respective side wall of the truck box; 
     a pair of panels each pivotally mounted on a respective one of the mounting rails for pivotal movement between a closed position and a raised open position; 
     each panel in the closed position extending inward from the corresponding mounting rail to a free end such that the free ends of the panels engage each other in the closed position of the panels; 
     each panel in the raised open position extending generally upward from the corresponding mounting rail such that the free ends are spaced apart; 
     two frame elements each mounted between the panels in the raised open position such that the panels are supported in an upright orientation for containing cargo in the truck box, the frame elements being mounted adjacent respective forward and rearward ends of the panels; 
     each mounting rail including a horizontal portion lying on the top surface of the respective side wall; 
     each panel having a spring member for assisting in supporting the weight of the panel as it is raised; 
     and a bracket for mounting on the truck box at a front wall of the truck box, the front wall of the truck box having an upstanding inner wall, a horizontal top surface and an outer depending flange; 
     wherein the bracket comprises: 
     a first member having a slot for engaging upwardly onto the depending flange; 
     and a second plate member; 
     the second plate member having a top plate arranged to extend over the top surface of the front wall of the truck box for the top plate to be bolted onto the first member 
     the second plate member having a second depending plate attached to the first plate and depending therefrom along the inner wall of the truck box, the depending plate having attached thereto a connector for receiving an end of the spring member. 
     Preferably the first member has a wall extending from the depending flange to the inner wall of the truck box and a bolt receptacle at the top surface for receiving a bolt extending downwardly from the top plate of the second plate member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings, which illustrate an exemplary embodiment of the present invention: 
         FIG. 1  is a bottom plan view of the two panels and the side rails for mounting the panels on the truck box according to a first embodiment of the present invention. 
         FIG. 2  is a bottom plan view similar to that of  FIG. 1  showing the panel on the driver&#39;s side that is the left hand side of the truck box on an enlarged scale. 
         FIG. 3  is a bottom plan view similar to that of  FIG. 1  showing only the panel on the passenger side which is the right hand side of the truck box. 
         FIG. 4  is a cross sectional view along the lines  4 - 4  of  FIG. 2 . 
         FIG. 5  is a cross sectional view along the lines  5 - 5  of  FIG. 2  showing the rail in the extended position. 
         FIG. 6  is a cross sectional view along the lines  6 - 6  of  FIG. 2 . 
         FIG. 7  is a cross sectional view along the lines  7 - 7  of  FIG. 2 . 
         FIG. 8  is a cross sectional view along the lines  8 - 8  of  FIG. 2 . 
         FIG. 9  is a cross sectional view along the lines  9 - 9  of  FIG. 2 . 
         FIG. 10  is a cross sectional view along the lines  10 - 10  of  FIG. 2 . 
         FIG. 11  is a cross sectional view along the lines  11 - 11  of  FIG. 2 . 
         FIG. 12  is a cross sectional view along the lines  12 - 12  of  FIG. 2 . 
         FIG. 13  is a cross sectional view along the lines  13 - 13  of  FIG. 2 . 
         FIG. 14  is a cross sectional view of a first arrangement for locking the end of the rail to the panel when in the retracted position. 
         FIG. 15  is a cross sectional view at the same location as that of  FIG. 14  showing an alternative arrangement for locking the end of the rail. 
         FIG. 16  is a cross sectional view through the front end wall of the truck box showing a bracket for attachment of the lower end of the gas spring for assisting lifting of the panel relative to the truck box. 
         FIG. 17  is a front elevational view of the bracket of  FIG. 16 . 
         FIG. 18  is a cross sectional view similar to that of  FIG. 4  showing an alternative arrangement of the mounting side rail  13 . 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1  is shown a tonneau cover generally indicated at  10  which includes a first panel  11  and a second panel  12  which can be placed over a truck box so that the panel  12  is on the drivers side and forms the left hand panel when viewed from the rear and the panel  11  is on the passenger side and forms the right hand panel when viewed from the rear. The view as shown in  FIG. 1  has the panels inverted to show the underside. 
     The truck box is of course not shown since this is well known to any person skilled in this art so that the truck box includes a front wall and two side walls together with a rear tail gate which is hinged at the bottom so that it can be folded downwardly to allow access into the truck box. The side walls of the truck box have a horizontal top surface which separates an inner wall of the truck box from the outer wall of the vehicle. Similarly the truck box has a front wall with a top surface with a front depending flange so that the top surface connects to the inside wall of the truck box at the front. 
     The panels are of a general arrangement which is known from the above prior art and each panel includes a side rail  13  which attaches to the top surface of the side wall of the truck box. The side rail is connected to the respective panel by a hinge  14 . Each panel has a rail  15  which is pivotally mounted at one end  16  to the respective panel. Thus the rail  15  of the drivers side panel  11  is attached at its end  16  adjacent the rear of the panel. Thus the rail  15  of the passenger side panel  12  is attached at its end  16  adjacent the forward end of the panel. Each rail has its opposite end, in a retracted position of the rail, latched as indicated at  17  to the underside of the panel. Each panel can be moved from a closed position lying across the top of the truck box where the inner side edges  18  of the panels are slightly overlapping. In the raised position of the panels obtained by pivoting the panels about the hinge  14 , the panels stand generally upwardly from the respective side wall of the truck box and the rails  15  are moved to an extended position pivotal about the end  16  so that the end  17  is moved into engagement with the opposite panel at a receptacle  19 . Thus in the raised position of the panels each rail extends across between the panels with the rail of the passenger side panel  12  at the front and the rail of the driver side panel  11  at the rear. Each of the panels includes a bracket  20  for receiving one end of an air cylinder (not shown) which extends from the bracket  20  to a corresponding bracket attached to the front wall of the truck box as described hereinafter. 
     The panel  11  also includes a locking system generally indicated at  21  in the form of a handle  22  which operates a rod  23  for actuating locking elements  24  at spaced positions along the panel. Locking elements engage with cooperating members on the opposite panel. 
     Turning now to  FIG. 4 , there is shown in more detail the arrangement of the outside portion of the panel  12  including the rail  13  and the hinge  14 . The panels  11  and  12  as shown in the cross section of  FIG. 4  are formed from a top or outer sheet  25  and an inner or bottom sheet  26 . Each of these sheets is moulded or vacuum formed from an ABS plastics material. The sheets are shaped to a required arrangement and then adhesively fastened together to provide the necessary structural strength. At the outer edge of the panel at the hinge  14 , the inner sheet  26  is bent downwardly to form a depending channel portion  27  with a bottom wall  28  and an upstanding outermost wall or lip  29 . In order to cooperate with this, the outer sheet  25  has a depending lip  30 . An outer surface of the lip  29  is adhesively attached to an inner surface of the lip  30  at a junction line  31 . The height of the two lips is such that the lip  29  is contained underneath the bottom surface of the outer sheet  25 . The bottom edge  32  of the lip  30  terminates at a position coterminous with the bottom wall  28 . The lip  30  thus forms a wall surface with an outer surface  33  which is generally at right angles to the horizontal top surface  34  of the outer sheet  25 . 
     The rail  13  is also formed from an outer sheet  35  and an inner sheet  36 . The outer sheet  35  is shaped to form an outer depending wall  37  which extends downwardly and outwardly to form a flange covering an outer flange  38  of the truck box indicated at  39 . At an inner edge, the rail  13  includes a depending wall  40 . The spacing between the walls  37  and  40  is such that the top portion  41  of the rail covers a top surface  42  of the side wall of the truck box with the depending inside wall  40  along the inside surface  42  of the side wall and the flange  38  being covered by the outside wall portion  37 . 
     At spaced positions along the length of the rail, the outer sheet is shaped to form a circular depression  44  to receive a bolt head  45  of a fastening bolt  46 . As shown in  FIG. 1  there is a limited number of such depressions  44  and in the embodiment shown there are four such depressions at spaced positions along the length of the rail  13 . 
     The inner sheet  36  is shaped so that a center portion  36 A contacts the underside of the sheet  35  and two side portions  36 B and  36 C depend downwardly to form channels with a bottom surface arranged to sit on the top surface  43  of the truck box side wall. These two channels of the inner sheet  36  thus support the center portion  41  of the outer sheet at a position spaced upwardly from the surface  43  of the side wall. 
     Within the channel  36 C is provided a series of holes  36 D at spaced positions along the length thereof each having a captive bolt  36 E contained therein for engaging through a hole in the top surface  43 . 
     Thus there is provided a row of the bolts  36 E which are arranged adjacent the inside surface  42  of the side wall of the truck box. Thus there is a second row of bolts  46  adjacent the outer flange  38 . The arrangement of the bolts  46  and the captive bolts  36 E is such that they match the design of the truck box of a particular manufacturer. The bolt fasteners  46  are arranged to co-operate with four stake holes of the truck box. The bolts  36 E are arranged in a row at spacing to co-operate with a row of attachment holes for the truck box side walls. 
     These fastening arrangements are designed for example with a truck such as a Ford F150 to match the fastening holes already in place in the truck box side wall where those fastening holes are conventionally used to fasten a top rail over the truck box side wall supplied by the manufacturer Ford. When it is intended therefore to apply the tonneau cover of the present arrangement, therefore, the side rail which is already in place is removed exposing the holes in the top rail of the side wall which are then used without additional drilling or any other modification to fasten the rail  13  to the side wall. 
     The fastening is effected by utilizing the bolt fasteners  46  which are of the butterfly-type and include spreading wings  46 A which pass through the hole in the side wall and then are spread by further tightening of the bolt  46  by actuation on the head  45  so as to pull the wings  46 A back up underneath the opening in the side wall to pull the head  45  down onto the side walls to clamp the rail in place. The head  45  includes a washer  45 A and an enclosing cap  45 B which engages around the head and includes a cover  45 C. It will be appreciated that the head  45  is accessible from the exterior of the truck box so that the first fastening can be effected by actuation of the bolt  46  to hold the bolts in place. The bolts  36 E simply pass through holes in the truck box side wall so that the end of the bolt is accessible from the inside of the truck box. The heads  36 F of the bolts  36 E are contained between the outer sheet  35  and the inner sheet  36  so as to be inaccessible from the exterior of the truck box. The installer can then apply a nut  36 G onto the bolt  36 E from the inside of the truck box. 
     When installed, therefore, it will be appreciated that the bolts  36 E are inaccessible from the exterior of the truck box so they cannot be removed from the exterior. When the cover is therefore closed and locked, the bolts are completely inaccessible thus preventing an unauthorized person from unbolting the cover and removing it from the truck box. 
     The two rows of fasteners provide a stable attachment of the rail to the truck box side wall since one wall is adjacent the inside and the other row is adjacent the outside thus preventing tilting of the rail on the side wall when forces are applied from the pivotal movement of the panel at the hinge  14 . 
     The butterfly fasteners can be replaced by clips which are attached to the panel and simply pop into the hole in the side wall without the necessity for screw fastening, bearing in mind that the main fastening is effected by the bolts  36 E. This allows the installation to be simplified by pop fastening the rail onto the side wall so that it is held in place by the pop or snap fasteners and then can be fastened more vigorously by the bolts  36 E. The use of the pop fasteners also overcomes the difficulty that the area where these fasteners are located is inaccessible from the exterior or interior of the truck box. 
     The hinge  14  comprises an inner piece  14 A which is attached to the surface  33  of the lip  30  and an outer piece  14 B which is attached to the depending wall  40  of the rail  13 . The hinge  14  is generally symmetrical and includes the inner piece  14 A and the outer piece outer piece  14 B together with a flexible interconnecting bridging member  14 C. The inner piece, the outer piece and the bridging piece are all continuous along the full length of the hinge and the hinge is continuous along the full length of the rail and the panel. The inner and outer piece each include a top lip portion  14 D and a depending flange portion  14 E which are adhesively attached to the respective end lip. 
     The bridging piece  14 C is molded from a different plastics material so that it provides flexibility whereas the inner and outer pieces are formed of a material which is more rigid to provide effective attachment of those inner and outer pieces to the respective lip. The bridging piece  14 C is sufficiently flexible so that it can bend through 90° allowing the panel to move from the horizontal position shown in  FIG. 4  to a raised vertical position (not shown) standing vertically upwardly at right angles to the position as shown. 
     The hinge thus provides a continuous closure between the panel and the rail so that there is no possibility for the penetration of the moisture therebetween. There is continuous attachment of each of the inner and outer pieces of the hinge to the respective portion of the rail and the panel and the bridging piece  14 C is continuous. 
     The facing surfaces of the inner piece  14 A and the outer piece  14 B include co-operating flange members  14 F. Thus the outer surface of the inner piece  14 A has a pair of flanges projecting outwardly and the inner surface of the outer piece  14 B includes a pair of flanges projecting inwardly. The flanges on the piece  14 A are spaced slightly further apart than the flanges on the piece  14 B so that when the panel is in the closed position as shown in  FIG. 4  the flanges prevent upward and downward flexing movement of the hinge which would allow the outer edge of the panel to move upwardly and downwardly relative the rail. Thus if the panel moves upwardly, the flanges at the bottom abut and if the panel moves downwardly the panels at the top abut. 
     Turning now to  FIG. 5 , there is shown more detail of the end  16  of the rail  15 . Thus a portion of the panel is indicated at  12  and includes the outer sheet  25  and the inner sheet  26 . The rail  15  carries a sleeve  15 A at the end  16  which attaches to a bracket  15 B by a bearing  15 C. The bracket  15 B includes a pair of legs  15 D and  15 E which are welded to a best plate  15 F. The base plate  15 F is mounted between the two sheets  25  and  26  so that it is received in a slightly recessed portion  26 A of the sheet  26  leaving the outside surface of the outer sheet  25  smooth. This provides therefore an effective technique for rigidly mounting the bracket  15 B and the bearing  15 C to the panel on the underside of the panel. The rail  15  is shown in  FIG. 5  in the extended position projecting outwardly from the pane  12 . It will be noted however that the rail  15  is not at right angles to the panel  12  but instead the panel  12  is inclined upwardly and slightly inwardly when the rail  15  is horizontal as shown. In this way it will be appreciated that the panels in their erected position when the rails are erected are inclined upwardly and inwardly from the hinge  14  to the top edge which is spaced therefore slightly inwardly from the side wall of the truck box. 
     Turning now to  FIG. 7 , there is shown the receptacle  19  on the opposite panel  11  for attachment to the opposite end  17  of the rail  15  of  FIG. 5 . At the end  17  is mounted a pin  17 A and this is arranged for co-operation with a gate latch  19 A on the opposite panel  11 . The opposite panel  11  is also formed from the outer sheet  25  and the inner sheet  26 . These are shaped similarly to the corresponding sheets of the panel  12  but it will be appreciated that there are slight differences in view of the position and location of the rail and the latch  19 A. 
     In  FIG. 7  it will be noted that sheet  25  is also smooth and extends continuous out to the edge  18  of the panel. At the edge  18  of the panel  11  is provided a lip  18 A which extends generally at right angles to the main body of the panel as defined by the outer surface  25 . The inner sheet  26  includes portions  26 B which are attached directly to the inside surface of the outer sheet  25  and recessed portions  26 C which form ribs  26 D which are spaced from the inside surface of the outer sheet  25  and thus provide structural ribs providing increased strength. Between the two ribs  26 D is provided the receptacle  19  for the latch  19 A. Embedded between the sheets  25  and  26  is provided a base -plate  19 B which is fastened to the inside surface of the outer sheet  25  and provides a support for the gate latch  19 A. It will be noted again that with the gate latch  19 A arranged at right angles to the length of the rail  15  for engagement onto the pin  17 A, there is an angle between the gate latch  19 A and the panel which is symmetrical to the angle between the end  16  of the rail and the panel  12  so that symmetrically the panels  11  and  12  are inclined upwardly and inwardly with the rail  15  horizontal. 
     Turning now to  FIGS. 6 and 8 , the structure of each of the panels is shown in more detail. Thus each of the panels includes the outer layer  25  and the inner sheet  26 . As shown in  FIG. 8  the outer sheet  25  has a smooth outer surface  50  and the inner sheet  26  is bonded to an inner surface  51  of the outer sheet at portions  52 . In between those two bonded sections recessed portions  53  which define a series of ribs  54  across the width of the panel. As shown in  FIG. 1  the ribs  54  extend from a position closely adjacent the hinge  14  at the outer edge inwardly through to the inner edge  18 . There is in addition a transverse rib  56  at a position spaced just outwardly of the rails  15 . Also at the rails the ribs  54  are recessed as indicated at  57  to define a recessed surface  58  against which the rails  15  rest in their retracted or stored position. In this position the rails are retracted below the rib  56 . The rib  56  acts as a stiffening member in the longitudinal direction of the panel. 
     As best shown in  FIG. 6  at the edges  18  of the panels, the panel  11  includes the down-turned lip  18 A which terminates at an edge  18 B. The inner sheet  26  is bonded to the inner surface of the sheet  25  at the inner surface  51  and also into the inner surface of the lip  18 A. Thus the lip is defined by the thickness of both the inner and outer sheets to provide strengthening effect to that lip. 
     The panel  12  is similarly formed from the outer sheet  25  and the inner sheet  26  and these sheets are molded to form a channel  60  into which the lip  18 A project. The channel  60  thus includes a depending wall  61 , a horizontal bottom wall  62  and an upstanding wall  63 . The upstanding wall  63  together with the bottom wall  62  and the depending wall  61  are all formed both from the inner and outer sheets to provide structural strength for the channel  60 . The outer sheet at the top of the outer wall  63  extends beyond the inner sheet to form a depending leg  64  and a smooth curved upper surface  65  which provides an attractive appearance to the edge of the channel  60 . In the closed position shown in  FIG. 6  the lip  18 A projects over the smooth upper surface  65  along side the depending leg  64 . The underside of the sheet  26  sits on the smooth surface  65  to provide a closure between the panels. The lip  18 A projects downwardly into the channel so as to provide in effect a labyrinth seal to prevent moisture from penetrating between the panels. Any moisture entering the channel  60  collects within the channel and is preventing from engaging over the upstanding wall  63  of the channel into the area between the panels. The channel has a discharge at the rear end over the tailgate so that any moisture collecting therein can run along the vehicle to the tailgate for discharge over the tailgate to prevent it entering into the truck box between the panels. 
     The panels are locked together by a plurality of toggle locks  24  as previously described. The toggle locks  24  comprise a body  24 A and a toggle locking member  24 B which moves into engagement with a plate  24 C on the underside of the bottom wall  62  of the channel. The toggle locking member  24 B moves in a direction controlled by a slot  24 D so that slides forwardly and moves downwardly underneath the plate  24 C. Movement of the toggle locking member  24 B is effected by rotation of the hexagonal shaft  23  which rotates a drive member in the body  24 A. Toggle locking members of this type are readily available and the details of operation of the movement of the toggle locking member are thus known to a person skilled in the art. The body  24 A is mounted on a plate  24 E clamped between the sheets  25  and  26  immediately adjacent the lip  18 A. 
     Turning now to  FIG. 13  there is shown the mounting of the handle  22  between the outer sheet  25  and the inner sheet  26  in an area between two lips  66  and  67  of those sheets. Thus the handle  22  is presented on the outside of a depending outside lip  66  of the panel  11 . The handle  22  attaches to a support and bearing  67  which allows the handle to rotate in the panel. At the end of the support  67  is provided a coupling  68  which attaches to the shaft  23 . The shaft  23  emerges through a hole  69  in a sheet  26  so that it extends underneath the panel to the toggle locking member  24 . 
     Turning now to  FIGS. 9 ,  10 ,  11  and  12 , there is shown the co-operation of the sheets  25  and  26  at the position adjacent the front and rear sides of the panel. Thus it will be noted in each case the outer sheet  25  at each position where the cross sections are taken includes a depending lip  70 . This co-operates with a portion of the sheet  26  which is spaced from the underside  51  of the sheet  25  but includes an upstanding lip  71  which is bonded to the lip  70  and extends upwardly toward the underside  51  of the sheet  25 . This arrangement in effect provides a box section along the front edge and along the rear edge of each of the panels to provide structural strength therefore. By comparing the cross sections  11  and  12  at the rear of the panel, it will be noted that the sheet  26  in  FIG. 12  which is closer to the side wall of the truck provides a distance D 1  between the top surface  72  of the sheet  25  and the bottom surface  73  of the sheet  26  at the lip  71  where the distance D 1  is smaller than the distance D 2  of  FIG. 11 . In this way it will be appreciated that the surface  73  of the inner sheet  26  sits on the top edge of the tailgate so that the surface  72  of the outer or top sheet of the panel increases in height relative to the top surface of the tailgate from the outside wall of the truck box towards the center of the truck box. This provides a slight pitch to the panels acting to assist in shedding water to the sides of the truck box. Similarly at the front of the truck box where the cross sections of  FIGS. 9 and 10  are taken, the distance D 3  is smaller than the distance D 4  so that again the panels are supported at a slight pitch angle relative to the front wall of the truck box. Also it will be note din  FIG. 10  that the surface  73  of the inner or lower sheet  26  has step  74  which is arranged at a position immediately adjacent the inside surface of the front wall of the truck box to define a further channel portion  75  which extends slightly into the truck box to assist in locating the panels and to increase structural strength adjacent the front edge of the panels. 
     While the cross sections of the panel are taken in relation to the panel  11  in  FIG. 2 , it will be appreciated that the shape of the panel  12  of  FIG. 3  is symmetrical in respect to these particular elements and in relation to the shaping of the inner and outer sheets, the only differences being in relation to the locking arrangement and the connection along the center line and in other respects the panels are substantially symmetrical. 
     Also shown in  FIG. 9  is the bracket  20  which attaches one end of the air assist cylinder (not shown). The bracket  20  includes a pin  20 A which attaches to a suitable coupling at the end of the cylinder. The pin  20 A is mounted on a flange  20 B of the bracket  20 . The flange  20 B is attached to a plate  20 C which is screw fastened to the surface  73  of the sheet  26  adjacent the lip  71 . The plate  20 C is thus flat against the surface  23  and the flange  20 B projects outwardly at right angles thereto so as to lie along the inside surface of the front wall of the truck box and supporting the pin  20 A so that it projects from the front wall of the truck box longitudinally of the truck box at a position spaced inwardly from the side wall. The pin  20 A thus supports the end of the cylinder which is attached to the panel so that the cylinder can apply force to the panel as it opens and closes. 
     Turning now to  FIGS. 16 and 17 , there is shown a bracket  80  for supporting a pin  81  from the wall of the truck box for receiving the other end of the cylinder attached to the pin  28 A. The bracket  80  includes a first bracket portion  82  which is attached on the outside of the front wall  83  of the truck box. The bracket further includes a plate portion  84  which clamps to the first portion  82  and supports the pin  81  inside the truck box at a position below the top edge of the truck box at the front wall of the truck box. 
     Thus the truck box includes the upstanding front wall  83  together with an outwardly or forwardly extending top flange  85  and a deep ending flange  86  from the front of the top portion  85 . The first bracket portion  82  is shaped to define a slot  87  which matches the flange  86  so that the slot can slide onto the flange  86  so that the leg  88  defining a rear side of the slot slides upwardly until it butt underneath the top plate  85  of the front wall of the truck box. A further leg  89  extends rearwardly from the slot into engagement with a front surface of the wall  83  of the truck box. This leg  89  together with the slot locate the first bracket portion  82  on the outside of the truck box wall at the front and present a receptacle  90  in front of the flange  86  for clamping to the plate portion  84 . 
     The plate portion  84  includes a vertical plate  91  and a horizontal plate  92  which connect together at a corner which engages over the top edge of the wall  83  onto the top plate  85  of the truck box. The horizontal plate  92  is clamped to the receptacle  90  by a threaded fastener  94 . This arrangement provides a simple mounting of the bracket to the front wall of the truck box without the necessity for drilling the truck box or forming other shapes or changes in the truck box itself. (It simply can be clamped onto the front wall of the truck box by sliding the slot portion or first portion underneath the flange  86  and then by screwing the plate  92  down onto the receptacle  90  to hang the plate  91  downwardly on the inside of the truck box to present the pin  81  rearwardly of the truck box for engaging the end of the air cylinder. 
     Turning now to  FIGS. 14 and 15  there are shown two different techniques for mounting the end of the rail  15  at the receptacle for the end  17  on the underside of the panel. In the arrangement shown in  FIG. 14 , the attachment of the end  17  to the panel  11  is provided by way of a spring pin  96  which projects into a hole  97  in the end of the rail  15 . The spring pin  96  includes a handle  98  and an operating button  99  which allows the spring pin  96  to slide through a bracket  100  attached to the panel  11 . The bracket  100  includes a base plate  101  clamped between the outer wall  25  and the inner wall  26 . Depression of the button  99  releases the pin  96  by retracting locking elements  102  allowing the pin to be withdrawn from the end of the hole in the rail  15 . This arrangement of a pin which extends longitudinally along the rail can accommodate significant changes in temperature which occur in certain climates which can differentially expand the panel itself relative to the metal rail thus changing the distance between the bracket  100  and the end of the rail. Such changes in distance are accommodated by a change in the location of the pin  96  within the hole  97  in the end of the rail. 
     In  FIG. 15  is shown an alternative arrangement for use where temperature changes are less dramatic which uses a simple gate latch  105  which receives and traps the pin  17 A shown in  FIG. 5 . The arrangement in  FIG. 15  is therefore preferred as a simple latching of the end of the rail  15  when it is moved to the retracted position since it can be simply held in place by engagement into the gate latch and can be readily released when required by the operator pressing on the gate latch. The gate latches can be operated by a suitable linkage pulled from one end. 
     As best shown in  FIG. 2  there are two toggle latches which are operated by the handle  22  and which engage under plates on the panel  12 . This number can be increased to provide a more aggressive locking action. In addition the toggle latches can be located closer to the ends so as to hold the ends more effectively attached to the ends of the truck box. In some cases this locking action may be insufficient to provide maximum security since it may still be possible for a user to apply a crowbar between the top edge of the truck box and the underside of the panels. In this case an additional locking element may be provided directly between the panel  11  and a loop fastened to the tailgate. This may be provided by a pin which moves longitudinally of the panel into the loop providing a hole at right angles to the tailgate so that the pin when engaged in the loop prevents the panel from being lifted away from the tailgate. 
     In  FIG. 18  is shown an alternative arrangement of the side rail  13  in which the mounting is simplified by use of a row of spring clip fasteners  46 B which snap fasten into holes  39 A in the truck rail  39 . Thus the rail can be snap fastened in place by the row of spring clips  46 B and then clamped down by the second row of fasteners  36  E as previously described. The spring clips are thus attached to the rail from the underside in a slot  46 C using a captive head  46 D. This avoids forming a hole in the wall of the rail to the top surface, as in the embodiment of  FIG. 4 , to provide a more attractive appearance and to avoid the fasteners  46  of  FIG. 4  being exposed for possible tampering. 
     Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.