Patent Publication Number: US-2022219516-A1

Title: Folding Tonneau Cover Having Secured Flexible Hinge

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/865,132, filed on May 1, 2020, which is a continuation in-part of U.S. application Ser. No. 16/252,345, filed on Jan. 18, 2019, now U.S. Pat. No. 11,235,652, which is a continuation of U.S. application Ser. No. 15/794,549, filed on Oct. 26, 2017, now U.S. Pat. No. 10,189,340, which claims the benefit of U.S. Provisional Application No. 62/414,591, filed on Oct. 28, 2016; this application also claims the benefit of U.S. Provisional Application No. 62/845,086, filed on May 8, 2019, and U.S. Provisional Application No. 62/843,357, filed on May 3, 2019, which applications are incorporated herein by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     A tonneau cover apparatus for covering an open bed or cargo box of a pickup truck or other truck or trailer. Particularly, a tonneau cover apparatus including a folding cover assembly having a plurality of panels that are interconnected in series by a series of hinges in such a manner that the respective panels can pivot with respect to one another, so as to fold up and unfold, and which is detachably fastenable to a support frame assembly including a pair of side rails, each of which is secured to one of two opposing sidewalls of the cargo box. 
     DESCRIPTION OF THE RELATED ART 
     Numerous protective cover assemblies for preventing rain, debris and wind from damaging or disrupting the contents of a pickup truck bed or cargo box are currently available. Among these protective cover assemblies are tonneau covers. Some tonneau covers are made of a fabric material, often a fabric coated with a polymeric material, which is fastened to a rigid frame so as to enclose and protect the pickup truck cargo box. Various covering materials are used for such tonneau covers; some are flexible and/or stretchable, and others are more rigid, and they are secured to the pickup truck in various manners to cover the cargo box. Tonneau covers are opened in various manners to allow entry into the cargo box, such as by rolling the cover up, folding the cover up, pivoting the cover upward from a location proximate the cab, or disconnecting and removing the cover from the cargo box altogether. 
     Typical tonneau covers have support frames including a pair of elongated side rails that are secured to the sidewalls of the cargo box of the pickup truck. Known tonneau covers are often secured to the side rails using hook and loop strip fastener components secured to the side rail, typically within a horizontal channel (see, e.g., U.S. Pat. Nos. 4,036,521; 4,991,640; 6,752,449 and U.S. Patent Application Pub. No. 2004/0212212 A1). Some tonneau covers are secured to the side rails by latches (see. e.g., U.S. Pat. No. 7,104,586). Some tonneau covers include rigid panels which are folded up for cargo access (see e.g., U.S. Pat. No. 10,189,340). 
     The present invention provides improvements that address limitations associated with the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention preferably includes a tonneau cover apparatus for removable attachment about a top of a perimeter of a cargo box of a pickup truck, the top of the perimeter of the cargo box including a forward end, two opposing sidewalls and a tailgate, the tailgate being positioned rearward of the forward end and having an open position and a closed position, the tonneau cover apparatus including: a support frame assembly for attachment to the cargo box; and a cover assembly for attachment to the support frame assembly when the support frame assembly is attached to the cargo box; the cover assembly preferably including a plurality of rigid panels and a flexible hinge; wherein the plurality of rigid panels include first and second panels flexibly secured to one another by the flexible hinge; the flexible hinge having a center portion, two side portions and two intermediate portions; wherein each of the respective intermediate portions separately interconnect one of the respective side portions to the center portion; wherein the cover assembly preferably further includes an elongated support member secured to an underside of one of the rigid panels; wherein the elongated support member has a main portion and a flange; wherein the main portion has an upper portion that is secured to an underside of the respective rigid panel and the flange extends away from the upper portion such that the flange resides at least partially below the respective underside and at least a portion of one of the two side portions; wherein the flange and the underside of the respective rigid panel preferably cooperate to form a partial enclosure within which the side portion is secured; and wherein the flange preferably has a lip and wherein the lip preferably extends toward the outer edge of the rigid panel so as to form a partial enclosure to retain at least a portion of the intermediate portion and the side portion of one side of the flexible hinge; and wherein at least a portion of the intermediate portion of the flexible hinge has a thickness that is greater than a gap between the outer edge of the rigid panel and any point on the outer surface of the lip of the support flange. 
     In a further embodiment, the present invention provides a tonneau cover apparatus for removable attachment about a top of a perimeter of a cargo box of a pickup truck, the top of the perimeter of the cargo box including a forward end, two opposing sidewalls and a tailgate, the tailgate being positioned rearward of the forward end and having an open position and a closed position, the tonneau cover apparatus including a support frame assembly for attachment to the cargo box; and a cover assembly for attachment to the support frame assembly when the support frame assembly is attached to the cargo box; the cover assembly including a plurality of rigid panels and a flexible hinge; wherein the plurality of rigid panels preferably include first and second panels flexibly secured to one another by the flexible hinge; the flexible hinge having a center portion, two side portions and two intermediate portions; wherein each of the respective intermediate portions separately interconnect one of the respective side portions to the center portion; and wherein each of the respective rigid panels have an underside, a topside and a perimeter surface surrounding a perimeter of each of the respective rigid panels; wherein a first portion of the perimeter surface of the respective rigid panel converges with a first section of the respective underside proximate the flexible hinge securing the first rigid panel to the second ridged panel to form a first edge that runs generally parallel to a length of the flexible hinge; wherein the cover assembly further includes an elongated support member secured to the respective underside of one of the respective rigid panels proximate the first edge; wherein the elongated support member has a main portion and a flange and the main portion has an upper portion that is secured to the respective underside of the respective rigid panel and the flange has an extended portion that extends away from the upper portion and resides below the underside when the support member is secured to the respective underside and a lip portion which runs generally parallel to the first edge and extends upward from the extended portion so as to reduce a width of a gap between the lip portion and the first edge such that the proximate portion of the flange resides at least partially below the respective underside proximate the first edge of the respective rigid panel so as to cooperate with the respective underside to form a partial enclosure in which at least a portion of the side portion of the respective hinge resides. 
     In a further embodiment of the present invention, a tonneau cover apparatus is provided for removable attachment about a top of a perimeter of a cargo box of a pickup truck, the top of the cargo box including a forward end, two opposing sidewalls and a tailgate, the tailgate being positioned rearward of the forward end and having an open position and a closed position, the tonneau cover apparatus including a support frame assembly for attachment to the cargo box; and a cover assembly for attachment to the support frame assembly when the support frame assembly is attached to the cargo box; the cover assembly including a plurality of rigid panels and a flexible hinge; wherein the plurality of rigid panels include first and second panels flexibly secured to one another by the flexible hinge; the flexible hinge having a center portion, two side portions and two intermediate portions; wherein each of the respective intermediate portions separately interconnect one of the respective side portions to the center portion; wherein the cover assembly further includes two elongated support members, each of which is secured to an underside of one of the rigid panels; wherein each of the elongated support members has a main portion and a flange; wherein the main portion has an upper portion that is secured to an underside of one of the respective rigid panels and the flange extends away from the upper portion such that the flange resides at least partially below the respective underside proximate an outer edge of the respective rigid panel when the respective elongated support member is secured to the respective rigid panel; wherein the respective flange and the underside of the respective rigid panel cooperate to form a partial enclosure within which one of the respective side portions of the flexible hinge is secured; wherein the flexible hinge is secured to the respective first and second rigid panels within respective first and second partial enclosures. 
     In yet another embodiment of the present invention, a tonneau cover apparatus is provided for removable attachment about a top of a perimeter of a cargo box of a pickup truck, the top of the cargo box including a forward end, two opposing sidewalls and a tailgate, the tailgate being positioned rearward of the forward end and having an open position and a closed position, the tonneau cover apparatus including a support frame assembly for attachment to the cargo box; and a cover assembly for attachment to the support frame assembly when the support frame assembly is attached to the cargo box; the cover assembly including a plurality of rigid panels and a flexible hinge; wherein the plurality of rigid panels include first and second panels flexibly secured to one another by the flexible; the flexible hinge having a center portion, two side portions and two intermediate portions, each of which extend a length of the flexible hinge, wherein each of the respective intermediate portions separately interconnect one of the respective side portions to the center portion; wherein the center portion is at least partially concave. 
     These and various other advantages and features of novelty which characterize the present invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, in which corresponding reference numerals and letters indicate corresponding parts of the various embodiments throughout the several views, and in which the various embodiments generally differ only in the manner described and/or shown, but otherwise include parts corresponding to the parts in the previously described embodiment; 
         FIG. 1  is a rear perspective view of a folding tonneau cover apparatus according to the present invention, including a folding cover assembly and a support frame assembly, and shown attached to a pickup truck which is shown in phantom; 
         FIG. 2A  is a top plan view showing the folding tonneau cover assembly shown in  FIG. 1  and also showing a protective film  574  on the top surface of the front panel  536   c , that is not shown in subsequent Figures, with the exception of  FIGS. 9A, 10A, and 10  B where the protective film shown is again shown; 
         FIG. 2B  is a bottom plan view of the folding tonneau cover apparatus of  FIG. 1 ; 
         FIG. 2C  is a side view of the folding tonneau cover apparatus of  FIG. 1  as viewed from line  2 C- 2 C of  FIG. 2A  which illustrates the driver&#39;s side of the pickup truck shown in  FIG. 1 ; however, for clarity of illustration, the perimeter seal on the underside of the outer edge of the respective panels is not shown; 
         FIG. 2D  is a detailed view of a portion of the folding tonneau cover apparatus encircled by the dashed line  2 D,  19 A of  FIG. 2C , illustrating the rear hinge, with a portion of the driver&#39;s-side side rail broken away to show the underlying structure; 
         FIG. 2E  is a detailed view of a portion of the folding tonneau cover apparatus encircled by dashed line  2 E of  FIG. 2C , illustrating the middle hinge and the front hinge, with a portion of the driver&#39;s-side side rail broken away to show the underlying structure; 
         FIG. 2F  is an enlarged detailed top plan view of a portion of the folding tonneau cover apparatus shown in the dashed rectangle  2 F of  FIG. 2A , with portions broken away to show the underlying structure and showing the support member in partial cross section and illustrating the engaging portion of the latch engaged with the containment bracket and the side rail, and showing an alternate position of the engaging portion of the latch in phantom when it is retracted from the containment bracket and with other structures shown in phantom to indicate the relative position of the respective elements; 
         FIG. 2G  is an enlarged perspective view as seen generally from a line  2 G- 2 G of  FIG. 2B  which is seen from below of a portion of a folding tonneau cover apparatus similar to the folding tonneau cover apparatus shown in  FIG. 2B , except that the side rail shown in  FIG. 2G  is an alternate passenger side rail  520   d , which differs from the side rail  520   b  shown in  FIG. 2B ; 
         FIG. 2H  is an exploded perspective view of an alternative driver&#39;s-side split side rail, that is a mirror image of the passenger side split side rail shown in  FIG. 2G , both of which have a plurality of sections which are joined together by a driver&#39;s side containment bracket; 
         FIG. 3A  is a rear perspective view of the folding tonneau cover apparatus of  FIG. 1 , illustrating additional details; 
         FIG. 3B  is a partial section view as seen from the line  3 B- 3 B of  FIG. 3A  illustrating the engaging portion of one of the latches on the rear support bow or support member of the rear panel engaged with the lip of the side rail and the side rail clamped to the sidewall of the pickup truck with a portion of the truck sidewall and sidewall cap shown in phantom; 
         FIG. 4A  is a rear perspective view of the folding tonneau cover apparatus of  FIG. 1 , with the release cord pulled to pull the latch against the bias of the spring to release the latch from the engagement with the side rail; 
         FIG. 4B  is a is a partial section view as seen from the line  4 B- 4 B of  FIG. 4A  similar to the view of  FIG. 3B , but showing the arrangement with the engaging portion of the latch retracted from the closed position where the latch would be engaged with the lip of the side rail; 
         FIG. 5A  is schematic illustration of a vertical cross section along a front-to-back plane as seen from the line  5 A- 5 A of  FIG. 2A  of one of the hinges of the folding tonneau cover assembly of  FIG. 1  showing the basic configuration with the hinge unfolded; 
         FIG. 5B  is a schematic illustration similar to  FIG. 5A  of a transverse vertical cross section along a front-to-back plane showing an alternate embodiment of one of the hinges of the folding tonneau cover assembly of  FIG. 1  showing the hinge unfolded; 
         FIG. 5C  is a schematic illustration showing the hinge of  FIG. 5B , but with the hinge folded at about 45 degrees from the unfolded orientation shown in  FIG. 5B ; 
         FIG. 5D  is a schematic illustration showing the general steps and configurations of the folding tonneau cover assembly of  FIG. 1  as it is folded up into a fully folded orientation; 
         FIG. 5E  is a further schematic illustration showing an alternate configuration of the fully folded orientation of the tonneau cover assembly of  FIG. 5D ; 
         FIG. 5F  is a further schematic illustration similar to that of  FIG. 5E , but showing yet another alternate configuration of the fully folded tonneau cover assembly; 
         FIG. 6A  is a rear perspective view of the folding tonneau cover apparatus of  FIG. 1  wherein the latches on the rear panel have been released to allow the rear panel to be lifted up in a first step toward folding up the tonneau cover assembly; 
         FIG. 6B  is a partial section view as seen from line  6 B- 6 B of  FIG. 6A  showing the hook or swing latch  562   a  near the driver&#39;s side end portion of the rear support bow of the middle panel retracted from catch  564   a  secured to the lip of the side rail; 
         FIG. 7A  is a rear perspective view of the folding tonneau cover apparatus of  FIG. 1  wherein the rear panel has been rotated forward onto the middle panel in a further step toward folding up the cover assembly; 
         FIG. 7B  is a partial section view as seen from the line  7 B- 7 B of  FIG. 7A  showing the engaging portion of the swing latch  562   a  disengaged from the catch  564   a;    
         FIG. 7C  is a schematic illustration similar to that shown in  FIG. 5C  showing the alternate hinge body of  FIG. 5B  but with the hinge body folded about 180 degrees as shown in the configuration illustrated in  FIGS. 7A-7B ; 
         FIG. 8A  is a rear perspective view of the folding tonneau cover apparatus of  FIG. 1 , wherein the rear panel is folded over onto the middle panel and wherein both panels have been lifted up and pivoted forward generally about 90 degrees with respect to the front panel that is resting on the side rails and is generally in a horizontal plane with respect to the pickup truck shown in part in phantom; 
         FIG. 8B  is a partial section view as seen from the line  8 B- 8 B of  FIG. 8A  showing the swing latch  562   c  near the driver&#39;s-side end portion of the support bow of the spacer panel disengaged from the corresponding catch  564   c;    
         FIG. 8C  is a side view as seen from the line  8 C- 8 C of  FIG. 8A , but illustrating the rear panel together with the middle panel engaged top surface to top surface as shown in  FIG. 8A , but showing the two panels rotated forward further than shown in  FIG. 8A  to the point that the standoff  558  touches the front panel  536   c;    
         FIG. 8D  is a side view similar to  FIG. 8C , except that the rear panel together with the middle panel are rotated further forward so that the standoff is touching the front panel and the spacer panel is lifted up and rotated partially forward; 
         FIG. 8E  is a side view similar to  FIG. 8D , except that the rear panel together with the front panel are rotated still further forward and the standoff is touching the front panel and the spacer panel is lifted up further and rotated further forward; 
         FIG. 8F  is a schematic illustration showing a transverse vertical cross section similar to that of  FIGS. 5C and 7C , but showing the spacer panel and two adjacent alternate hinges of the folding tonneau cover assembly of the present invention, illustrating both of the alternate hinges in a partially folded configuration similar to the partially folded orientation shown in  FIG. 8D ; 
         FIG. 9A  is a rear perspective view of the folding tonneau cover apparatus of  FIG. 1  showing the rear panel together with the middle panel and the spacer panel rotated forward so that the middle panel and the rear panel are resting together on the top of the front panel, with the spacer panel rotated upward generally at a 90 degree angle to the other panels in a fully folded orientation, but also showing the standoffs  558  resting on alternate protective films  574  shown only in  FIGS. 2A, 9A, 10A, and 10B  as an alternate element in those figures; 
         FIG. 9B  is a partial section view as seen from the line  9 B- 9 B of  FIG. 9A  illustrating the driver&#39;s side of the completely folded tonneau cover assembly showing the rear support bow of the front panel resting on the lip of the driver&#39;s side side rail; 
         FIG. 10A  is a front perspective view of the folding tonneau cover apparatus of  FIG. 1  wherein the rear panel together with the middle panel and the spacer panel have been pivoted or rotated forward so that the middle panel and the rear panel are resting on the top surface of the front panel as in  FIG. 9A  and showing the alternate protective film on the front panel engaged by the standoff  558  which rests on the protective film  574 ; 
         FIG. 10B  is a front perspective view of the folding tonneau cover apparatus of  FIG. 1  similar to the view of  FIG. 10A , but showing the storage strap  543   a  pulled down and a strap bracket  543   b  engaged with a bracket slot  543   c  on the front edge of the front panel, securing the folding tonneau cover assembly  530  in the fully folded up configuration; 
         FIG. 10C  is a front view of the folding tonneau cover apparatus of  FIG. 1  showing a storage strap toward each side of the folded tonneau cover, with each storage strap pulled down and a strap bracket engaged with a bracket slot on the front edge of the front panel, securing the folding tonneau cover in the folded up configuration; 
         FIG. 10D  is a side view from the driver&#39;s side of the folding tonneau cover apparatus of  FIG. 1  in the configuration of  FIG. 10C  further showing the fully folded configuration and schematically illustrating the flexible hinges in the folded-up configuration, with one of the storage straps being visible and a strap bracket engaged with a bracket slot on the front panel, securing the folding tonneau cover in the fully folded up configuration; 
         FIG. 10E  is a schematic illustration showing a transverse vertical cross section similar to that of  FIG. 8F , showing the a spacer panel and two adjacent hinges of the folding tonneau cover of  FIG. 1 , illustrating both of the alternate hinges in a 90-degree folded configuration; 
         FIG. 11A  is a rear perspective view of the folding tonneau cover apparatus of  FIG. 1  viewed from slightly below and to the driver&#39;s side of the folding tonneau cover apparatus, wherein the folding tonneau cover assembly is secured in the fully folded up configuration similar to that of  FIGS. 10B-10D , showing a release cord for pulling the latches on the front panel against the bias of the springs to release the latches and schematically illustrating the flexible hinges in a manner similar to that in  FIG. 10D ; 
         FIG. 11B  is a partial view of the portion of the folding tonneau cover apparatus of  FIG. 1  shown in the dashed rectangle  11 B of  FIG. 11A , illustrating clip cord guides and a retainer cord guide and a corresponding release cord along a support bow, with the support bow shown in phantom to reveal the underlying structures; 
         FIG. 12  illustrates the folding tonneau cover assembly  530  of  FIG. 1 , secured in the fully folded up configuration disengaged from the support frame assembly  518  and being held in the arms of an operator; 
         FIG. 13A  illustrates a clip cord guide aligned for attachment to a support bow or support member; 
         FIG. 13B  illustrates the clip cord guide of  FIG. 13A  inserted into a channel of the support bow; 
         FIG. 13C  illustrates the clip cord guide of  FIGS. 13A and 13B  rotated so that an oblong securement feature engages the clip cord guide within the channel of the support bow; 
         FIG. 13D  illustrates a retainer cord guide secured to a support bow; 
         FIG. 14A  is a perspective view illustrating a standoff; 
         FIG. 14B  is a side view illustrating the standoff of  FIG. 14A  with longitudinal groove  558   b  engaged with a sidebar  559  secured to the bottom surface of the rear panel  536   a  and showing the support bow in phantom; 
         FIG. 14C  is a side view illustrating the standoff of  FIGS. 14A and 14B  pivoted upward so that the longitudinal groove  558   c  is engaged with the sidebar as shown and illustrating a standoff distance between a top of the protective pad on the standoff and the top surface of the rear panel and showing the support bow in phantom; 
         FIG. 15A  illustrates a preferred perimeter seal in a transverse vertical cross section; 
         FIG. 15B  illustrates an alternate perimeter seal in a transverse vertical cross section; 
         FIG. 15C  illustrates a further alternate perimeter seal in a transverse vertical cross section; 
         FIG. 15D  illustrates another alternate perimeter seal in a transverse vertical cross section; 
         FIG. 15E  illustrates another alternate perimeter seal in a transverse vertical cross section; 
         FIG. 15F  illustrates a rigid panel edge guard in a transverse vertical cross section; 
         FIG. 15G  illustrates a still further alternate perimeter seal in a transverse vertical cross section; 
         FIG. 15H  illustrates a further alternate perimeter seal in a transverse vertical cross section; 
         FIG. 16A  illustrates a front view of a support bow or support member; 
         FIG. 16B  illustrates an alternate support bow similar to the support bow of  FIG. 16A , but wherein the alternate support bow has a slight bend or deflection of the support bow making its upper surface curved downwardly at the ends; 
         FIG. 16C  is an end view of the support bow of  FIG. 16B  showing the deflection d; 
         FIG. 16D  is a schematic illustration of a front view of a rigid panel  536 ′ of the folding tonneau cover of  FIG. 1 ; 
         FIG. 16E  is a schematic illustration of a rigid panel of  FIG. 16D  after being attached to the support bow of  FIG. 16B , causing the panel to have a slight downwardly concave curvature reflecting the deflection of the alternate support bow of  FIG. 16B ; 
         FIG. 16F  is a perspective view of a straight support bow or support member with no hinge support flange and no downward deflection; 
         FIG. 16G  is a perspective view of a curved support bow or support member with no hinge support flange and a downward curvature or deflection; 
         FIG. 16H  is a perspective view of a straight support bow with one hinge support flange having a lip; 
         FIG. 16I  is a perspective view of a curved support bow having a downward deflection and one hinge support flange having a lip; 
         FIG. 16J  is a perspective view of a straight support bow having two hinge support flanges; 
         FIG. 16K  is a perspective view of a curved support bow having two hinge support flanges and a downward deflection; 
         FIG. 17A  is a cross sectional detail view as seen from the line  17 A- 17 A in  FIG. 3A , showing additional details in the vicinity of the side of the spacer panel, and showing two flexible hinges, a latch, a containment bracket, a hook, and a catch; 
         FIG. 17B  is a cross sectional detail view similar to the view shown in  FIG. 17A , but with one of the flexible hinges folded up from the side rail, similar to the configuration of  FIG. 8A ; 
         FIG. 17C  is a perspective view of a hinge body of the folding cover assembly of  FIG. 1  shown isolated and in an unfolded configuration; 
         FIG. 17D  is a perspective view of a portion of the hinge body including a transverse vertical cross sectional view of the hinge body taken from the dashed rectangle  17 D shown in  FIG. 17C ; 
         FIG. 17E  is a view that is similar to the view shown in  FIG. 17D , except that the hinge body that is shown is an alternate hinge body; 
         FIG. 17F  is a view that is similar to the view shown in  FIG. 17D , except that the hinge body that is shown is an alternate hinge body; 
         FIG. 17G  is an enlarged schematic illustration similar to that shown in  FIG. 18J , which is referenced herein below, except that the hinge body is different which allows the configuration of the partial enclosure  592  to engage the alternate hinge body  545   a ′″ in a slightly different manner wherein the panel  336  does not abut against the hinge body  545   a ′″ the same way that is shown in  FIG. 18J ; 
         FIG. 17H  is a further enlargement of a portion of the hinge body  545   a ′″ and the partial enclosure  592  in which the hinge body is secured and also showing the gap  590  between a first point  593   a  on the lip  587   b  of the flange  586   b  of the support bow  550  and a second point  593   b  at the lower corner of the panel  536  which is taken from the dashed circle  17 H of  FIG. 17G ; 
         FIG. 18A  is a schematic illustration similar to that of  FIG. 5A , but illustrating an alternative embodiment of the support bows each having a flange, but neither of which have a flange lip; 
         FIG. 18B  is a schematic illustration similar to that of  FIG. 5A , but illustrating an alternative embodiment of the hinge body  545   a ′ having a single hinge body polymer material and having support bows that have a lip at the end of each of the support flanges of the partial enclosure; 
         FIG. 18C  is a schematic illustration similar to that of  FIG. 18B , but illustrating a further alternative embodiment of the hinge body  545   a ″ made of a single polymeric material and having a flat central portion; 
         FIG. 18D  is a schematic illustration similar to that of  FIG. 18B , but illustrating a further alternative embodiment of the hinge body  545   a ′″ made of a single polymeric material that is secured on each side within a partial enclosure created by the panel  536  and the support bow  550  without an adhesive securing the side portion to the rigid panel; 
         FIG. 18E  is an enlarged schematic perspective illustration similar to that of  FIG. 17G , but with the hinge body shown partially secured within a partial enclosure  592  created by rigid panels  536 , one of which is partially broken away, and support bows having a lip at the end of each of the support flanges of the partial enclosure; 
         FIG. 18F  is an enlarged schematic perspective view of the portion of  FIG. 18E  shown in the dashed circle  18 F, but with the rigid panels and support bows shown only in part; 
         FIG. 18G  is a further schematic perspective view similar to  FIG. 18E  but showing the structure of the partial enclosure  592  with the hinge body shown only partially in phantom, with the rigid panels and support bows shown in cooperation with one another as shown in  FIG. 18D ; 
         FIG. 18H  is an enlarged view providing a transverse vertical cross section of the portion of the folding tonneau cover assembly shown in  FIG. 18A , but showing the hinge body  545   a  in phantom; 
         FIG. 18I  is an enlarged view similar to that shown in  FIG. 18H , except that the hinge body  545   a  is shown in cross section and the rigid panels  536  and the support bows  550  are shown in phantom; 
         FIG. 18J  is an enlarged view of the portion of the folding tonneau cover assembly  530  shown in the dashed circle  18 J of  FIG. 18I ; 
         FIG. 19A  is a detail side view of a portion of the folding tonneau cover apparatus of  FIG. 1  as viewed from line  19 A- 19 A as indicated in  FIG. 3A , with the side rail on the driver&#39;s side in phantom and the truck removed to show the underlying structure, and showing in phantom an alternate position of the same portion of the folding tonneau cover apparatus in which the rear panel has been lifted up and rotated frontward somewhat so that the hook is disengaged from the catch; 
         FIG. 19B  is a detail side view similar to that of  FIG. 19A , but in which the rear panel has been rotated completely forward onto the middle a panel; 
         FIG. 19C  is a schematic illustration of steps and configurations of the folding tonneau cover apparatus of  FIG. 1  showing the folding cover assembly being installed onto the side rails, showing the hooks at the front of the front panel approaching the catches at the front of the side rails, then the hooks at the front of the front panel engaged with the catches at the front of the side rails and the latches at the rear of the front panel engaged with the side rails and the respective containment brackets, then the spacer panel and middle panel unfolded with the hooks at the front of the middle panel engaged with the respective catches on the side rails, then the rear panel unfolded with the hooks at the front of the rear panel engaged with the respective catches on the side rails and the latches at the rear of the rear panel engaged with the respective side rails and containment brackets; 
         FIG. 20A  is a schematic illustration of the folding tonneau cover apparatus of  FIG. 1 , as configured for a cargo box having angled sides; 
         FIG. 20B  is a schematic illustration of the folding tonneau cover apparatus of  FIG. 1 , as configured for a cargo box having parallel sides; 
         FIG. 20C  is a schematic illustration of the folding tonneau cover apparatus of  FIG. 1 , as configured for an elongated cargo box; 
         FIG. 20D  is a schematic illustration of the folding tonneau cover apparatus of  FIG. 1 , as configured for a shorter cargo box; 
         FIG. 20E  is a schematic illustration of the folding tonneau cover apparatus of  FIG. 1 , as configured for a cargo box with arbitrary shape; 
         FIG. 21A  is a schematic illustration of a portion of the folding tonneau cover apparatus of  FIG. 1 , illustrating a flexible hinge interconnecting two adjacent panels, showing bent or bowed support bows creating a bending or bowing of the panels attached thereto (see also  FIGS. 16B-16E, 16G, 16I, and 16K ), with the bending or bowing exaggerated for illustration, with the panels unfolded; and 
         FIG. 21B  is a schematic illustration similar to that of  FIG. 21A , showing the panels folded up, and together with  FIG. 21A  illustrating how the flexible hinge can accommodate the folding up and unfolding of such bent or bowed panels. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, a folding tonneau cover apparatus  510  of the present invention is attachable to sidewalls  6   a ,  6   b  of a cargo box  5 , such as the cargo box of a truck or pickup truck  2 , which is shown in phantom. In  FIG. 1 , the folding tonneau cover apparatus  510  is shown in a typical application covering the top opening  6   f  (shown in phantom in  FIG. 12 ) of the cargo box  5  of the pickup truck  2 . The pickup truck  2  and the cargo box  5  and the sidewalls  6   a  and  6   b  and the front wall  6   c  ( FIG. 12 ) at the forward end of the cargo box  5  and the tailgate  6   d  at the rear end of the cargo box  5  are not a part of the present invention, but are shown in phantom to illustrate a typical application and function of the folding tonneau cover apparatus  510  in covering a cargo box  5 , which has a length  7   a  and a width  7   b . The perimeter of the cargo box  5  includes the forward end or front wall  6   c , the opposing sidewalls  6   a  and  6   b , and the rearward end or tailgate  6   d , which is shown in part. The rearward end or tailgate  6   d  preferably can be opened or closed. It will be appreciated that the perimeter of the top opening of the cargo box  5  will include top surfaces of the front wall  6   c , the two sidewalls  6   a ,  6   b , and the tailgate  6   d  when the tailgate is in a closed position (not shown). As further illustrated in  FIGS. 2A-3B , the folding tonneau cover apparatus  510  includes a folding tonneau cover assembly, tonneau cover assembly or cover assembly  530  and a support frame assembly  518 , including side rails or rails  520   a  and  520   b . In preferred embodiments, side rails  520   a  and  520   b  are secured to sidewalls  6   a  and  6   b  with clamps  514 . In preferred embodiments, the folding cover assembly  530  is configured to be opened to an open position and closed to a closed position, and easily removed and reinstalled by a driver or other operator  8  ( FIG. 12 ), as needed. The side rails  520   a  and  520   b  are constructed and arranged to facilitate securement of the folding cover assembly  530  to the side rails  520   a  and  520   b . In some embodiments, the side rails  520   a  and  520   b  have a side rail lip  524  and a side rail engagement portion  522   a . In this example, there are eight clamps  514  arranged to hold the side rails  520   a  and  520   b  to the sidewalls  6   a ,  6   b  of the pickup truck  2 , but other numbers of clamps  514  can be used. In some embodiments, the clamps include an outer member  516   a , an inner member  516   b , a clamp engagement portion  516   c , and a fastener assembly  516   d ; the fastener assembly can, for example, include a bolt  516   e , a washer  516   f  and a nut  516   g  as illustrated. 
     Referring again to  FIGS. 2A-2C , the folding tonneau cover apparatus  510  of  FIG. 1  is shown in whole or in part, but the truck  2  and the cargo box  5  are not shown.  FIG. 2A  shows a top view of the folding tonneau cover assembly  530  of  FIG. 1 . The top 532a of the folding cover assembly  530  is shown. The folding cover assembly  530  includes rigid panels or panels  536 . In this example, panels  536  include a rear panel  536   a , a middle panel  536   b , a front panel  536   c , and a spacer panel or hinge panel  536   d . For ease of discussion, panels  536  are specifically referenced herein as  536   a - 536   d , and non-specifically or collectively referenced as rigid panels  536 . The folding cover assembly  530  includes a plurality of such rigid panels  536 , and could potentially have from two to 8 panels  536 ; for example, 6 panels  536  could be used, including 4 “longer” panels (similar to panels  536   a - 536   c  shown herein) and  2  “shorter” panels (similar to panels  536   d  shown herein). While a smaller or a larger number of panels  536  can be used (not shown), the inventors have found that the configurations illustrated herein provide a good trade-off of convenient folded configuration vs. complexity. 
     As shown in  FIG. 2A , and also as further described herein with respect to  FIGS. 20A-20E , the length  539  of each of the panels  536   a - 536   d  is indicated as  539   a - 539   d , respectively. In this example, the spacer panel  536   d  has a substantially smaller length  539   d  than the other panels, as will be further described herein. In preferred embodiments, the length  539   d  of the spacer panel  536   d  is preferably no greater than about one-third of the length  539   a - 539   c  of the other panels  536   a - 536   c . Panels  536   a - 536   d  can have similar length  539 , or the length of some or all of panels  536   a - 536   d  can differ. The width  540  of each of the panels  536   a - 536   d  is indicated as  540   a - 540   d , respectively. Panels  536   a - 536   d  can have the same width  540 , or the width of some or all of panels  536   a - 536   d  can differ. The side angle  542  of each of the panels  536   a - 536   d  is indicated as  542   a - 542   d , respectively, in  FIG. 20A . Panels  536   a - 536   d  can have the same side angle  542 , or the side angle  542  of some or all of panels  536   a - 536   d  can differ. Alternative configurations of folding tonneau covers  530  appropriate for covering the cargo box  5  of various models of pickup truck  2  are further described below. Each panel  536  has a top surface  537  and a bottom surface or underside  538 ; panel  536   a  has a top surface  537   a  and a bottom surface or underside  538   a , panel  536   b  has a top surface  537   b  and a bottom surface or underside  538   b , panel  536   c  has a top surface  537   c  and a bottom surface or underside  538   c , panel  536   d  has a top surface  537   d  and a bottom surface or underside  538   d.    
     As further described herein and illustrated in drawing  FIGS. 2A-5F , the present invention includes a folding tonneau cover assembly  530  having a plurality of rigid panels  536  arranged in a series, with adjacent rigid panels  536  secured to each other by a flexible hinge  544 , so that the folding cover tonneau cover assembly  530  can be unfolded to cover a top opening  6   f  ( FIG. 12 ) of a cargo box  5  of a truck  2 , and folded up to uncover at least a portion of the top opening  6   f  of the cargo box  5  of the truck  2 . Each rigid panel  536  has a front edge  541   b  and a rear edge  541   c  and a driver&#39;s side edge  541   d  and a passenger side edge  541   e  and a top surface  537  and a bottom surface or underside  538 . When the folding tonneau cover assembly  530  is unfolded and arranged to cover the top opening  6   f  of the cargo box  5 , each of the rigid panels  536  extends between the driver&#39;s side  3   a  and the passenger side  3   b  of the cargo box  5 , and each flexible hinge  544  extends between the driver&#39;s side and the passenger side of the cargo box. In embodiments having 4 rigid panels  536 , for example, there are 3 flexible hinges  544 , each flexible hinge  544  being secured to two adjacent rigid panels  536 . Other configurations are possible, including embodiments having two rigid panels  536  and one flexible hinge  544 , embodiments having three rigid panels  536  and two flexible hinges  544 , embodiments having five rigid panels  536  and four flexible hinges  544 , embodiments having six rigid panels  536  and five flexible hinges  544 , and so forth. In preferred embodiments, the number of rigid panels  536  is 1 greater than the number of flexible hinges  544 ; alternative embodiments include folding tonneau cover assemblies  530  having at least three rigid panels  536  and at least one flexible hinge  544 , as described herein, and at least one other hinge or connection as may be known in the art (not shown) have been envisioned by the inventors. The present invention includes such embodiments, as long as the embodiments include at least one flexible hinge  544  as described herein. 
     Also illustrated in  FIG. 2A , is a protective film  574  on the top surface  537   c  of the front panel  536   c . As described further herein and illustrated in  FIGS. 2A, 9A, 10A, and 10  B, alternate embodiments of the folding tonneau cover assembly  530  include the protective film  574 , which protects the top surface  537   c  of the front panel  536   c  when the folding tonneau cover assembly  530  is folded up and the standoffs  558  are in contact with the top surface  537   c . As described below, a protective pad  558   a  is preferably attached to the bottom of each standoff  558 , but abrasion of the top surface  537   c  can occasionally occur when the protective pads  558   a  are in direct contact with the top surface  537   c , especially when the pickup truck on which the folding cover assembly  530  resides is travelling on rough road surfaces that cause the protective pads  558   a  to vibrate on the top surface  537   c . While the protective film  574  is optional to reduce or prevent such abrasion in some embodiments, they are not required. Such alternate embodiments of the present invention, which include the protective film  574  to minimize abrasive damage to the top surface  537   c , are disclosed herein. Protective film  574  can be obtained from a variety of suppliers, including Avery Dennison (Glendale, Calif.), 3M (St. Paul, Minn.), Arlon (Placentia, Calif.), and Xpel (San Antonio, Tex.). One preferred protective film  574  is Avery Dennison SW 900 Series Supreme Wrapping Film. The protective film  574  is preferably applied to specific locations on the top surface  537   c  which will align with the standoffs  558  when the folding tonneau cover assembly  530  is folded up as shown and described herein. For example, for embodiments including 4 standoffs  558 , protective film can be applied to the top surface  537   c  in the locations shown in  FIG. 2B . The protective film  574  is preferably located in locations on the top surface  537   c  as schematically illustrated on  FIG. 2A  that correspond to the locations that the protective pads  558   a  of the standoffs  558  will assume when they engage the top surface  537   c  of the front panel  536   c , when the folding cover assembly  530  is in a fully folded up orientation. 
       FIG. 2B  shows a bottom view of the folding tonneau cover apparatus  510 . Visible in this view are hinges or flexible hinges  544 , which are situated between adjacent panels  536  and adjoin adjacent panels  536 . For ease of discussion, hinges  544  are specifically referenced herein as  544   a - 544   c , and non-specifically or collectively referenced as  544 . Specifically, situated between the rear panel  536   a  and the middle panel  536   b  is hinge  544   a . Similarly, situated between the middle panel  536   b  and the spacer panel  536   d  is hinge  544   b , and situated between the spacer panel  536   d  and the front panel  536   c  is hinge  544   c . Hinges  544  allow the folding cover assembly  530  to be folded up and will be more fully described below. Support bows  550  are attached to the panels  536  to provide additional support and rigidity to the panels  536 , and also provide a structure for mounting of various other components as described in detail later herein. For ease of discussion, support bows  550  are specifically referenced herein as  550   a - 550   g , and non-specifically or collectively referenced as  550 . The folding tonneau cover assembly  530  is removably secured to the support frame assembly  518  by securing apparatus  551   a . Preferably, securing apparatus  551   a  includes at least one locking member  551   b  which is engageable and disengageable from the support frame assembly  518 . Preferably, the locking member  551   b  includes latches  552  which are located at the support bows as shown and secure the folding cover assembly  530  to the side rails  520   a  and  520   b . Release cords  554  are attached to the latches  552 . For ease of discussion, latches  552  are specifically referenced herein as  552   a - 552   d , and non-specifically or collectively referenced as  552 . Also for ease of discussion, release cords  554  are specifically referenced herein as  554   a - 554   b , and non-specifically or collectively referenced as  554 . The release cords  554  pass through cord guides  555  which are attached to support bows  550  as shown. Cord guides  555  preferably include clip cord guides  555   a  and retainer cord guides  555   b , which will be described in further detail below. Standoffs  558  are shown, and will be described in further detail below. Sidebars or handles  559  are attached to panels  536   a ,  536   b , and  536   c , near each side of each panel  536  to further support the panels  536 . Perimeter seal  534  is located on the bottom  532   b  of the folding cover assembly  530  and is arranged to seal against top of the perimeter of the cargo box  5  at the sidewalls  6   a  and  6   b  and the front wall  6   c  and the tailgate  6   d  of the cargo box  5  as shown; some portions of perimeter seal  534  are behind side rails  520   a  and  520   b  and not visible  FIG. 2B . The perimeter seal  534  is further described herein. 
     The support bows or transverse frame members or channels  550  provide additional support for the panels  536 . In this embodiment, the panels each have two support bows  550 , one located near each of the front and rear ends of each panel  536 , except for the spacer panel  536   d , which has only a single support bow  550 . In this embodiment, there are latches  552  mounted in pairs, one of each pair mounted near each end of each of the support bows  550   a  and  550   f  as shown. As further described below, the latches  552  engage the side rails  520   a  and  520   b  to secure the folding cover assembly  530 , and can slide a short distance towards or away from the side rails  520   a  and  520   b  to engage or release the folding cover assembly  530  or portions thereof or selected panels  536  from the side rails  520   a  and  520   b  as further described below. Note that the support bows  550   b ,  550   c ,  550   d ,  550   e , and  550   g  do not have associated latches  552  in this embodiment. In this embodiment, there are two latch release cords or release cords or cords  554 , each of which are connected to opposing pairs of latches  552  which secure the panels  536  to the side rails  520   a  and  520   b . The release cords  554  preferably pass through cord guides  555  which are mounted to the support bows  550 ; the release cords  554  can slide within or behind the cord guides  556  as further described herein. The release cords  554  generally extend from the latches  552  along the support bows  550 . As illustrated in  FIGS. 2B and 2C , the clamps  514  secure the side rails  520   a  and  520   b  to the sidewalls  6   a  and  6   b  of the cargo box  5 . The folding tonneau cover apparatus  510  is seen in a side view from the driver&#39;s side in  FIG. 2C . 
     In further reference to  FIGS. 2C-2E , the portion of the folding tonneau cover apparatus  510  that includes the rear hinge  544   a , as indicated by the encircled area labeled  2 D in  FIG. 2C , is illustrated in an enlarged partial cutaway view in  FIG. 2D . Similarly, the portion of the folding tonneau cover apparatus  510  that includes the middle and front hinges  544   b  and  544   c , respectively, as indicated by the encircled area labeled  2 E in  FIG. 2C , is illustrated in an enlarged partial cutaway view in  FIG. 2E . The folding cover assembly  530  preferably includes extended hinge support flange(s)  586  located adjacent the bottom surface or underside  538  of the respective panel  536  and near the front and rear edges  541   b  and  541   c , respectively, of the rigid panels  536  to which the flexible hinges  544  are secured (for example,  FIG. 5A ). As will be described in further detail below, the flexible hinges  544  each preferably includes a flexible hinge body  545   a  which includes a central portion  546   a , side portions  546   b  and  546   c , and intermediate portions  546   d  and  546   e . Each side portion  546   b  and  546   c  preferably extends between the extended hinge support flange  586  and the rigid panel  536 . Adhesive  570   a  is preferably located between each side portion  546   b  and the respective rigid panel  536  to protect against passage of debris or precipitation into the cargo box  5 ; the adhesive  570   a  can also aid in securement of the hinge body  545   a  to the respective rigid panel  536 . The support bows or channels  550  are preferably secured to the bottom surface or underside  538  of the rigid panels  536 , near the front edge  541   b  and/or rear edge  541   c  of the rigid panels  536 . Each support bow  550  that is adjacent a flexible hinge  544  preferably includes the extended hinge support flange  586 . Further details regarding the structure of the flexible hinge body  545   a  and securement to the rigid panels  536  are described below. 
     The folding tonneau cover apparatus  510  preferably includes containment brackets  525   a  and  525   b . The structure and function of the containment bracket  525   a  is further illustrated in  FIG. 2F . Note that in  FIG. 2F , portions of the rigid panels  536  and the flexible hinges  544  are broken away to reveal the underlying structure, and many elements are illustrated in phantom to emphasize the elements being described. When the engaging portion  553   b  is engaged under the side rail  520   a  and is contained by the containment bracket or anchor socket  525   a  as illustrated in  FIG. 2F , the engaging portion  553   b  is contained by the containment bracket  525   a  so that it cannot slide frontwards or rearwards along the side rail  520   a . The containment bracket  525   a  is preferably secured to the side rail by a fastener assembly  526 , which may include a bolt, nut, washer, or other fasteners known in the art. In this configuration, the spring  568  is urging the latch slide  553  outwards towards the side rail  520   a . To release the latch  552  and allow the folding cover assembly  530  to be lifted off and removed from the side rail  520 , the release cord  554   e  is pulled. When the release cord  554   e  has been pulled, retracting the latch slide  553  and compressing the spring  568 , and disengaging the engaging portion  553   b  from the side rail  520   a  and the containment bracket  525   a , and releasing the latch  552 , the configuration is as illustrated in phantom in  FIG. 2F . The side rail  520   b  preferably has a mirror-image configuration to the side rail  520   a , with a side rail front portion  521   c  and side rail rear portion  521   d , and a containment bracket  525   b  functioning in a similar manner. 
     Some embodiments include the alternative side rail  520   c  which includes a plurality of sections  521  as illustrated in  FIG. 2G ; the side rail  520   c  preferably includes side rail front portion  521   a  and side rail rear portion  521   b . The containment bracket  525   a  is preferably secured to the side rail  520   c  by a fastener assembly  526 , which may include a bolt  516   e , nut  516   f , washer  516   g , or other fasteners known in the art. In these embodiments, in addition to its function to retain the latch  552  as previously described, the containment bracket  525   a  preferably facilitates securement of the side rail front portion  521   a  and side rail rear portion  521   b  together. One advantage of the “split” side rail  520   c  is that storage and shipment of the side rail  520  can be more practical; a one-piece side rail would be long and in some cases could be more difficult or expensive to transport, for example. The side rail  520   d  preferably has a mirror-image configuration to the side rail  520   c , with a side rail front portion  521   c  and side rail rear portion  521   d , and a containment bracket  525   b  functioning in a similar manner as the similar elements just described. The alternative side rail  520   c , containment bracket  525   a , and fastener assembly  526  are illustrated in exploded view in  FIG. 2H . Preferably, a tether  580  is attached to the containment bracket  525   b  and is releasably secured by a link  581  when desired to a ring  582  that is secured to the support bow  550   e ; this arrangement provides additional stabilization of the folding cover assembly  530  when the folding cover assembly  530  is secured to the side rails  520   a ,  520   b  and will secure the folding cover assembly  530  to the side rail  520  if other attachments fail. 
     In describing preferred embodiments of the present invention in the description that follows, it will be appreciated that reference will be made either to the “driver&#39;s side” or “passenger side” or to the “front” or to the “rear” of the folding tonneau cover apparatus or portions thereof in a manner that is consistent with the orientation of the folding tonneau cover apparatus when it is secured to a vehicle as envisioned, so that the “rear” of a folding tonneau cover apparatus or portion thereof will be consistent with what is seen when one is looking at the rear of such a vehicle when the folding tonneau cover apparatus or portion(s) thereof are attached to such a vehicle as envisioned herein, or such portion thereof which is closer to the rear. The “driver&#39;s side” refers to the side corresponding to the side of the vehicle typically used by the driver to operate the vehicle in North America, and the “passenger side” refers to the side opposite the “driver&#39;s side”. For clarity, the “length” of the folding tonneau cover apparatus, the folding cover assembly, the hinges, and the panels described herein, refers to a measurement of the “front” to “rear” dimension, since the pickup truck and the cargo box are typically longer in that direction. Similarly, “width” of the folding tonneau cover apparatus, the folding cover assembly, the hinges, and the panels described herein, generally refers to the “driver&#39;s side” to “passenger side” direction, since the pickup truck and the cargo box are typically shorter in that direction. However, these terminologies, that are used as a matter of convenience, are not intended to be limiting; the folding tonneau cover apparatus could be shorter in the “length” direction than in the “width” direction, for example. For other items such as support bows and sidebars, “length” has the normal meaning, referring to the longer dimension or to the dimension along an extruded shape, for example; any potential confusion in terminology can be eliminated by examination of the various Figures in the accompanying drawings. 
     Referring now to  FIGS. 3A and 3B , the release cord  554   a  near the rear end of the rear panel  536   a  passes through cord guides  555 ,  555   a ,  555   b .  FIG. 3B  is an enlarged partial section view of the driver&#39;s side end portion of the support bow  550   a  as indicated in  FIG. 2A . The cord guides  555  are preferably molded and made of a strong polymer such as Nylon, which may be reinforced with fiberglass or other embedded material to strengthen the polymer. In alternate embodiments, the cord guides  555  can made of polymeric, metallic or ceramic materials using three-D printing methods or three-D etching methods or other additive or subtractive machining process. One of the standoffs  558  can be seen in  FIG. 3A , and will be described in more detail later. 
     As seen in  FIG. 3B , the latch  552  includes latch slide  553  having an engaging portion  553   b  which extends forward to engage the lip  524  of the side rail  520   a , so as to secure the respective panel  530  to the side rail  520   a . The latch slide  553  preferably includes a stiff polymer, composite, or metal, although other materials and combinations can be used. Preferably, the latch slide  553  includes fiberglass-reinforced nylon. The latch slide  553  is biased by a biasing member or spring  556  towards the side rail  520   a  so that the engaging portion  553   b  engages the side rail  520   a  to form a secured configuration in which the respective panel  530  is restricted from being lifted up from the cargo box  5 ; in this example, the spring  556  is a compression spring, but an extension spring, or an elastic element, or other known elements could alternatively be used to bias the latch slide  553  towards the side rail  520   a  so that the engaging portion  553   b  engages the side rail  520   a  so that the latch  552  is in the secured configuration. In this embodiment, the spring  556  is held between the latch slide  553  and a spring retainer assembly  557 . The spring retainer assembly  557  is secured in the desired location in the support bow  550   a . The side rails  520   a  and  520   b  preferably include extruded metal, and have a side rail engagement portion  522   a  ( FIG. 3B ), arranged to approximate a portion of the sidewall  6   a ,  6   b  of the pickup truck  2 . The clamp  514  is shown in detail in  FIG. 3B . The clamps  514  preferably include aluminum, although other metals or alloys or polymers or other composite materials can be used. Clamps  514  preferably have an outer member  516   a  and an inner member  516   b  which are tightened towards each other and held as an assembly on the sidewall  6   a  by a fastener assembly  516   d  which preferably includes a bolt  516   e , a washer  516   f , and a nut  516   g . Preferably, inner member  516   b  has a clamp engagement portion  516   c  which, together with side rail engagement portion  522   a  of side rail  520   a , aids in securing the clamps  514  in place on the side rail  520   a . Preferably, the clamps  514  are arranged and tightened to secure the side rail  520   a  to the sidewall  6   a , with a sidewall gasket  522   c  arranged between the side rail  520   a  and the sidewall  6   a  as illustrated. A bow end cap  565  is located at the end of the support bow  550   a . A release cord  554  and a cord guide  555  are shown, and will be described in further detail herein. In the present example, the side rail engagement portion  522   a  is a generally vertically-oriented portion which configured to be located adjacent a similarly vertically-oriented portion of the sidewall  6   a ,  6   b . In the example of  FIG. 3B , a portion of the sidewall  6   a  of a cargo box  5  of a Chevrolet Silverado pickup truck is illustrated; however, other sidewalls of other cargo boxes of other pickup trucks and the like can be accommodated, by incorporating a side rail engagement portion  522   a  along the length of the side rails  520   a  and  520   b  that are appropriately configured and oriented. In this example, the cargo box  5  of the pickup truck  2  includes a sidewall cap  6   e , but other cargo boxes  5  lack a sidewall cap. A sidewall  6   a  and sidewall cap  6   e  are similarly illustrated in subsequent drawings herein, including  FIGS. 4B   6 B,  7 B,  8 B and  9 B. Preferably, the side rail engagement portion  522   a  has a side rail engagement feature  522   b , such as ridges, knurling, surface patterns or textures, or other features which aid in securing the clamps  514 . Preferably, a sidewall gasket  522   c  preferably made of polymeric material is located between the side rail engagement portion  522   a  and the sidewall  6   a ; the sidewall gasket  522   c  can provide protection against damage to the sidewall  6   a  by abrasion against the side rail  520   a . Other flexible material can also be used. The sidewall gasket  522   c  can provide leak resistance to prevent water, dust, or other debris from passing into the cargo box  5  along the side rail engagement portion  522   a . The side rail  520   a  has a flange or side rail lip  524  along the length of the side rail  520   a . The side rail lip  524  provides support for the folding cover assembly  530 . In addition, the side rail lip  524  provides a feature for engagement of the engaging portion  553   b  of the latches  552 . The driver&#39;s side portion of the support bow  550   a  is shown in  FIG. 3B ; the other end of the support bow  550   a  (toward the passenger side) has a mirror-image configuration, with a latch  552  engaging side rail  520   b , and side rail  520   b  being attached to sidewall  6   b  in a similar manner. 
     As illustrated in  FIGS. 4A and 4B , when it is desired to release the latches  552  at the rear end of the rear panel  536   a , the release cord  554   a  can be pulled, which will retract each of the latches  552  against the force of the respective biasing member or spring  568 . Typically, the release cord  554   a  will be pulled as illustrated in  FIG. 4A , by a driver (not shown) who has walked to the rear of the cargo box  5  and has opened the tailgate  6   d  and reaches in to access and pull the release cord  554   a . When the release cord  554   a  is pulled, the engaging portion  553   b  of the latch  552  is retracted away from the lip  524  of the side rail  520   a  as shown in  FIG. 4B , releasing the latch  552  from the side rail  520   a  and allowing the rear portion of the rear panel  536   a  to be lifted up from the side rail  520   a . The cord guides  555  adjacent to the latches  552  help to maintain alignment of the ends of the release cord  554   a  so that the latches  552  are retracted in alignment with the support bow  550   a , to avoid excessive friction, wear and potential binding. The driver&#39;s side portion of the support bow  550   a  is shown in  FIG. 4B ; the other end of the support bow  550   a  (toward the passenger side) has a mirror-image configuration, and when the release cord  554   a  is pulled, the latches  552  at both ends of the support bow  550   a  are retracted, so that the rear end of the rear panel  536   a  can be lifted up from both side rails  520   a  and  520   b.    
     Referring now also to  FIGS. 5A-5D , which illustrate a portion of the folding cover assembly  530  in schematic cross section views as indicated by the line  5 A- 5 A in  FIG. 2A , each of the hinges  544  ( 544   a ,  544   b , and  544   c ) preferably includes the flexible hinge body  545   a  which is elongated and extends between the driver&#39;s side  3   a  and the passenger side  3   b  of the cargo box  5  when the folding cover assembly  530  is unfolded to cover the cargo box  5 . The flexible hinge body  545   a  has a hinge longitudinal axis  545   b  which is oriented along the length of the hinge body  545   a , and a hinge body profile  545   c , which is the shape of a transverse vertical cross section taken perpendicular to the hinge longitudinal axis  545   b . The hinge body profile  545   c  is preferably uniform along the hinge longitudinal axis  545   b  of the hinge body  545   a . In embodiments having more than one flexible hinge  544 , each of the flexible hinges  544  can have a similar hinge body profile  545   c . Alternatively, the hinge body profile  545   c  of the flexible hinge bodies  545   a  can differ from the profile of at least one other of the flexible hinge bodies  545   a.    
     The folding tonneau cover assembly  530  of the present invention may include one of several different hinge body embodiments  545   a ,  545   a ′,  545   a ″,  545   a ′″ (see also  FIGS. 17C-18F ). The first embodiment  545   a , shown in  FIGS. 5A-5C  and  FIGS. 17A-17D , is a dual durometer hinge having a more flexible polymer material  547   c  making up the central portion  546   a  and a portion of the intermediate portion  546   d ,  546   e  adjacent to and on each side of the central portion  546   a , and a more rigid or stiff polymer material  547   d  making up the side portions  546   b ,  546   c  and a portion of the intermediate portion  546   d ,  546   e  on each side of the central portion  546   a  of the first embodiment of the hinge body  545   a . The first embodiment of the hinge body  545   a  will take more than one form depending on the format of the adhesive material attached to the hinge body for the purpose of sealing and sealing the hinge body  545   a  to the underside of the respective rigid panels  536  on either side of the respective hinge  544   a ,  544   b ,  544   c . In reference to the first embodiment of the hinge body  545   a  shown in  FIG. 5A , hinge body  545   a  is secured to the underside of the respective rigid panels  546  by an adhesive material  570   a  described elsewhere herein. In reference to the hinge body  545   a  shown in  FIG. 5B , hinge body  545   a  is secured to the underside of the rigid panels  536   a ,  536   b , respectively, by an adhesive member  571   a  described elsewhere herein. In reference to the hinge body  545   a  shown in  FIG. 5C , the hinge body  545   a  is secured to the underside of the respective rigid panels  536   a ,  536   b  with a three-part adhesive member having first, second, and third layers  572   a ,  572   b ,  572   c , as further described elsewhere herein. The first embodiment is also shown in  FIGS. 17A-17D  in the first adhesive format employing the adhesive material  570   a.    
     A further embodiment of the hinge body  545   a ′ having similar adhesive  570   a  for sealing and securing the hinge body  545   a ′ to the underside of rigid panels  536  but having only a single durometer polymer design is shown in  FIG. 17E . This single-durometer embodiment of the hinge body  545   a ′ is also shown in  FIG. 18B , but with a different adhesive  571  format. A further embodiment of the hinge body  545   a ″ is shown in  FIG. 18C  and is generally the same as the single-durometer hinge body  545   a ′ shown in  FIG. 18B , except that the central portion  546 ″ of the hinge body  545   a ″ does not include a concave upper surface like hinge body  545   a ′, but has instead a flat central portion  546 ″ in which water will not pool or run off along the length of the hinge body toward the sidewalls of the pickup truck  2 . The hinge body  545   a ′″ shown in  FIGS. 17F-17H  and  FIGS. 18D-18F  is also a single-durometer hinge body made of a flexible polymer material  547   c  and it does not need an adhesive member to secure it to the underside of the rigid panels, because the close proximity of the rigid panel  536  and the support bow  550 , which has ha hinge support flange  586  having a flange lip  587 , which cooperate to form a partial enclosure  592 , described elsewhere herein, which will hold the hinge body  545   a ′″ in place on each side of the hinge body  545   a ′″ as shown in  FIGS. 17G, 17H, and 18D-18F . The inventors have found that even when adhesive  570   a ,  5701   a , or other adhesives or adhesive members as described herein are not required for securement of the hinge body  545   a ,  545   a ′,  545   a ″,  545   a ′″ to the partial enclosure  592 , such adhesives or adhesive members can be advantageously included to provide a seal between the hinge body and the respective adjacent panels  536  against intrusion by moisture or debris into the cargo box  5  when the folding cover apparatus  530  is unfolded and covering the cargo box  5 . 
     The flexible hinge body  545   a ′″ preferably includes a single polymer material  547   a , and provides an effective barrier against influx of moisture, precipitation or debris into the cargo box  5  between the adjacent rigid panels  536  when the folding cover assembly  530  is unfolded and in place covering the cargo box  5 . The hinge body polymer material  547   a  preferably includes an elastomeric polymer material  547   b  and more preferably includes a thermoplastic polymer. The elastomeric polymer material  547   b  is preferably extruded to form an elongated structure having the desired hinge body profile  545   c . Examples of the preferable elastomeric polymer material  547   b  include Sarlink® TPE RV-2250D BLK 111 thermoplastic elastomer and Sarlink® TPV 5765B thermoplastic vulcanizate, both available from Teknor Apex Company, Pawtucket, R.I. 
     Each flexible hinge body  545   a  preferably includes the two side portions  546   b  and  546   c , and the central portion  546   a  located between the two side portions  546   b  and  546   c ; each flexible hinge body  545   a  preferably includes the two intermediate portions  546   d  and  546   e , each one of the intermediate portions  546   d  and  546   e  located between the central portion  546   a  and one of the two respective side portions  546   b  and  546   c . The central portion  546   a , side portions  546   b  and  546   c , and intermediate portions  546   d  and  546   e  of the flexible hinge body  545   a  preferably extend along the length of the flexible hinge body  545   a , and the hinge thickness  545   d  of the central, side, and intermediate portions  546   a - 546   e  together at least partially define the hinge body profile  545   c . Each of the two side portions  546   b  and  546   c  is preferably secured to a respective adjacent rigid panel  536 . When it is desired to fold up the folding tonneau cover assembly  530 , one of the adjacent rigid panels  536  is lifted up and folded towards the other of the adjacent rigid panels  536 , and the central portion  546   a  bends to function as a hinge as further described herein. 
     In some embodiments, such as schematically illustrated in  FIGS. 5A-5C , the flexible hinge body  545   a  includes more than one polymeric material such as those described herein; for example, the flexible hinge body  545   a  may include a softer or lower-durometer elastomeric polymer material  547   c  and a harder or higher-durometer elastomeric polymer material  547   d . The central portion  546   a  preferably includes the softer elastomeric polymer material  547   c , and the side portions  546   b  and  546   c , which are secured to the rigid panels  536  as stated, preferably include the harder elastomeric polymer material  547   d . In such embodiments, a transition or mixing of the materials preferably occurs in the intermediate portions  546   d  and  546   e . This arrangement preferably provides a structure with the central portion  546   a  being more flexible in bending than the intermediate portions  546   d  and  546   e  and the side portions  546   b  and  546   c , so that bending of the flexible hinge body  545   a  preferentially occurs in the central portion  546   a , although some flexing and bending can occur in other portions of the flexible hinge  544  in addition to the central portion. This arrangement is schematically illustrated in  FIG. 5C , which shows the hinge illustrated in  FIG. 5B  somewhat bent. In the drawings, which illustrate embodiments of the hinge body  545   a  having more than one polymeric material, the intermediate portions  546   d  and  546   e  have a transition between polymeric materials schematically indicated by a partially diagonal line in the drawings. As just described, the transition between materials may be gradual with a mixing of the polymeric materials in the intermediate portions, which will generally occur during either a molding process or an extrusion process, either of which could be used to manufacture a dual-durometer hinge body, so, for that reason, the line is not intended to define a precise sudden transition, but rather just generally indicate that the respective intermediate portion includes a transition between the different polymeric materials that have different durometers. Depending on the process and mixing of materials during fabrication of the hinge body, the transition can be more sudden or more gradual. The transition between polymeric materials will generally be located in the respective intermediate portions  546   d  and  546   e  as indicated by the schematic transition line shown in these portions. 
     For example, in one preferred embodiment, the central portion  546   a  includes the softer elastomeric polymer material  547   c , one example of which is Sarlink® TPE RV-2250D BLK 111 thermoplastic elastomer, and the side portions  546   b  and  546   c  include the harder or higher-durometer elastomeric polymer material  547   d , one example of which is Sarlink® TPV 5765B thermoplastic vulcanizate. These materials can be extruded together to form the disclosed structure, with a mixing of these materials occurring in the intermediate portions  546   d  and  546   e . The thickness  545   d  of the various portions of the flexible hinge body  545   a  can also affect the bending properties, but the variation of polymeric materials as just described can be useful in facilitating bending of the hinge  544  in the central portion  546   a , which in use is located between the adjacent panels  536 , and in facilitating securement of the side portions  546   b  and  546   c  to the adjacent panels  536 . 
     While forming the flexible hinge body  545   a  by extrusion of thermoplastic elastomers such as those listed above is preferred, other materials and fabrication methods can be utilized. For example, the flexible hinge body  545   a  can include a structure fabricated by molding or other additive or subtractive manufacturing process. The flexible hinge body  545   a  may have additional material added, such as reinforcing fibers or filaments (not shown) adhered to or incorporated into the flexible hinge body  545   a , including cloth-inserted, cloth-reinforced, fiberglass-reinforced, and fiber-reinforced polymer materials. The hinge body polymer material  547   a  can include a vinyl material, natural or synthetic rubber or other flexible polymeric material, EPDM rubber, neoprene rubber, nitrile rubber, latex, silicone rubber, polyurethane material, or other polymer materials known in the art, or combinations of materials. The flexible hinge body  545   a  preferably includes a flexible material that can withstand deformation without failure due to cracking or breakage to allow bending of the hinge  544  to fold up the folding cover assembly  530 , and that is moisture-resistant to avoid leakage into the cargo box  5 . 
     As stated above, adhesive  570   a  is preferably located between each side portion  546   b  and the respective rigid panel  536  as illustrated in  FIG. 5A  to protect against passage of debris or precipitation into the cargo box  5 ; the adhesive  570   a  can also aid in securement of the flexible hinge  544  to the respective rigid panel  536 . The adhesive  570   a  can include known adhesives and sealant materials which can be used to protect against passage of debris or precipitation between the rigid panel  536  and the respective flexible hinge  544  or to secure the flexible hinge  544  to the respective rigid panel  536 . In some preferred embodiments, the adhesive  570   a  includes a double-sided adhesive tape  571   a , which preferably includes an acrylic foam material  572   a , with adhesive layer  572   b  arranged on one side of the acrylic foam material  572   a , and adhesive layer  572   c  arranged on the other side of the acrylic foam material  572   a , for example. For example, the double-sided adhesive tape  571   a  can be 3M 5933 from 3M, St. Paul, Minn. (“thermal adhesive tape”), the adhesive layer  572   b  includes heat-activated adhesive and an adhesive layer  572   c  includes pressure-sensitive adhesive which may be protected by a release strip (not shown) until it is desired to activate the pressure-sensitive adhesive layer  572   c . Preferably, the adhesive layer  572   b  (in this example, heat-activated adhesive) is aligned with the flexible hinge body  545   a  while the heat-activated adhesive is activated to adhere the double-sided adhesive tape  571   a  to the flexible hinge body  545   a ; the flexible hinge body  545   a  together with the attached double-sided adhesive tape  571   a  is subsequently aligned with the rigid panel  536  and the release strip is removed. Preferably, after the adhesive layer  572   c  is aligned with the panel  536 , the flexible hinge body  545   a  is attached to the rigid panel  536  by activating the adhesive layer  572   c  (in this example, pressure-sensitive adhesive). The adjacent rigid panel  536  is similarly attached to the flexible hinge body  545   a  with double-sided adhesive tape  571   a  forming the structure of hinge  544  illustrated in  FIG. 5B . The flexible hinge body  545   a  allows the hinge  544  to take a flat or open configuration as illustrated in  FIGS. 5A and 5B , or to flex or bend as illustrated in  FIGS. 5C, 7C , and other figures herein, providing a flexible hinge  544  that allows the folding cover assembly  530  to fold as illustrated throughout the Figures and described herein, with rigid panels  536  folding up and rotating towards other rigid panels  536  as shown. Preferably, the flexible hinge body  545   a  is adhered to the respective bottom or underside  538  of the rigid panels  536  (specifically, the underside  538   a - 538   d  off respective adjacent panels of  536   a - 536   d  as described herein) of the folding cover assembly  530  as shown. In the preferred arrangements discussed herein, the hinges  544  are securely attached to the respective rigid panels  536  and are sealed to prevent water or debris from entering the cargo box through the folding cover assembly  530  at the hinges  544 , and are generally impervious to environmental factors such as precipitation, wind, and temperatures to which a typical cargo box  5  would be exposed. 
     The support bows  550  are also schematically illustrated in  FIGS. 5A-5C . The support bows preferably include a bow main portion  584  including a generally C-shaped channels with a bow upper portion  585  configured for attachment to the bottom surface  538  of the respective panel  536  and oriented with a channel opening  566   c  at the bottom. The support bows  550  which are located at the flexible hinges  544  preferably include the hinge support flange  586 ,  586   a ,  586   b ; the support bows which are located at the flexible hinges  544  preferably also include the flange lip  587 ,  587   a ,  587   b.    
     As stated above, the support bows  550  are secured to the respective panel  536 . The support bows  550  are preferably located at the bottom surface  538  of the respective panel  536 , and near the front edge  541   b  or rear edge  541   c  of the respective panel  536 . The support bows  550  are preferably secured to the bottom surface  538  of the respective panel  536  by an adhesive  570   b , which may include a layer or coating of adhesive or a double-sided adhesive tape  571   b , for example. Alternatively, a thermal or hot-melt or chemically activated adhesive, or a mechanical attachment, or a weld, or a combination, can be used to attach the support bows  550 , to the respective panels  536 . The double-sided adhesive tape  571   b  preferably includes an acrylic foam material  572   d  with adhesive layer  572   e  arranged on one side of the acrylic foam material  572   d  and adhesive layer  572   f  arranged on the other side of the acrylic foam material  572   d , for example. Preferably, the adhesive  570   b  includes a double-sided adhesive tape  571   b  such as 3M CV62F from 3M, St. Paul, Minn. (“pressure adhesive tape”), wherein the double-sided adhesive tape  571   b  is an acrylic foam tape having an adhesive layer  572   e  which includes pressure-sensitive adhesive and having an adhesive layer  572   f  which includes pressure-sensitive adhesive which may be protected by a release strip (not shown) until it is desired to activate the pressure-sensitive adhesive, adhesive layer  572   f . Preferably, the adhesive layer  572   e  (in this example, pressure-sensitive adhesive) is aligned with and adhered to the upper surface  566   d  of the support bow  550  to adhere the double-sided adhesive tape  571   b  to the support bow  550 ; the support bow  550  together with the attached double-sided adhesive tape  571   b  is subsequently aligned with the panel  536  and the release strip is removed. Preferably, the adhesive layer  572   f  is then aligned with the panel  536  and the support bow  550  is attached to the respective panel  536  by activating the adhesive layer  572   f  (in this example, pressure-sensitive adhesive). While the arrangement just described is a preferred configuration, any of the adhesive layers just described can include heat-activated adhesive or pressure-sensitive adhesive, and the acrylic foam material  572   a ,  572   d  is also preferable but not always required. For example, in alternative configurations, a single layer of adhesive could be used, similar to the arrangement schematically illustrated in  FIG. 5A . Other pressure-activated acrylic adhesive foam tape can be used, such as Lamatek 5357 from Lamatek, Inc., West Deptford, N.J. The sidebars or handles  559  are preferably also attached to the bottom surface or underside  538  of the respective panels  536 , preferably in a similar manner as that just described for the support bow  550 . Although adhesive  570   b  can be applied at selected portions of the length of the support bow  550  or the sidebar  559 , adhesive  570   b  is preferably applied along substantially the entire length of the support bow  550  and the sidebar  559 , to enhance stability and to minimize unwanted vibrations. Alternatively, the sidebars  559  and support bows  550  can be attached to the panels  536  with adhesives such as glue, or with fasteners, or spot welds. 
     In some apparatus and methods embodiments, the folding cover assembly  530  folds in stages or steps; a preferred embodiment is schematically illustrated in  FIG. 5D . In this embodiment, starting from the unfolded or closed configuration of the folding cover assembly  530  (configuration 1), the hinge  544   a  flexes to allow the rear panel  536   a  to fold up, passing through 90 degrees (configuration 2) towards the middle panel  536   b , and fold over onto the middle panel  536   b  (configuration 3). The hinge  544   b  flexes to allow the middle panel  536   b  (together with the rear panel  536   a  which is folded onto the middle panel  536   b ) to fold up, passing through 90 degrees (configuration 4) towards the spacer panel  536   d , passing through a point at which standoffs  558  contact the front panel (configuration 5). The hinge  544   b  flexes back towards 90 degrees as the hinge  544   c  flexes to allow the spacer panel  536   d  to fold up, and continue to fold over (together with the rear panel  536   a  which is folded onto the middle panel  536   b , and the middle panel  536   b ) towards the front panel  536   c  (configuration 6), until the folding cover assembly  30  is folded up (configuration 7). Note that  FIG. 5D  is a schematic overview of the general folding of the folding cover assembly  530 ; the various configurations are further illustrated and described elsewhere herein in greater detail. 
     An alternate configuration of an alternate folding cover assembly  530 ′ folded up is schematically illustrated in  FIG. 5E . In some embodiments, the front panel  536   c ′ is noticeably longer than panels  536   a  and  536   b . In some embodiments, the spacer panel  536   d  is oriented approximately vertically when the folding cover assembly  530  is folded up, and the front panel  536   c  simply extends farther frontward than the middle panel  536   b  and the rear panel  536   a . In the example illustrated in  FIG. 5E , the spacer panel  536   d  is correspondingly longer to accommodate the lengths of the panels  536   a ,  536   b , and  536   c ′ as illustrated. In this case, the spacer panel  536   d  is noticeably non-vertical when the folding cover assembly  530 ′ is folded up. The alternate folding cover assembly  530 ′ also preferably includes corresponding flexible hinges  544   a ,  544   b ,  544   c  and standoffs  558 . 
     Another alternate configuration of an alternate folding cover assembly  530 ″ folded up is schematically illustrated in  FIG. 5F , similar to the illustration of  FIG. 5E . In some embodiments, the front panel  536   c ″ is noticeably shorter than panels  536   a  and  536   b . In some embodiments, the spacer panel  536   d  is oriented approximately vertically when the folding cover assembly  530  is folded up, and the middle panel  536   b  and the rear panel  536   a  simply extend farther frontward than the front panel  536   c . In the example illustrated in  FIG. 5F , the spacer panel  536   d  is correspondingly longer to accommodate the lengths of the panels  536   a ,  536   b , and  536   c ″ as illustrated. In this case, the spacer panel is noticeably non-vertical when the folding cover assembly  530 ″ is folded up. The alternate folding cover assembly  530 ″ also preferably includes corresponding flexible hinges  544   a ,  544   b ,  544   c  and standoffs  558 . 
     In the examples illustrated in  FIGS. 5E and 5F , the spacer panel  536   d  can be oriented preferably from about zero to about 60 degrees from a vertical orientation; the orientation is determined by the various lengths of the panels  536  and a standoff distance  561   a  (see  FIG. 14C ). When the cover assembly is in the fully folded position, the top surface  537   d  of the spacer panel  536   d  can stand generally at an angle of from about 30 to about 150 degrees to the top surface  537   c  of the front panel  536   c , preferably from about 40 to about 140 degrees to the top surface  537   c  of the front panel  536   c ; more preferably from about 50 to about 130 degrees to the top surface  537   c  of the front panel  536   c ; even more preferably from about 60 to about 120 degrees to the top surface  537   c  of the front panel  536   c , and even more preferably from about 80 to about 100 degrees to the top surface  537   c  of the front panel  536   c , generally depending upon the length of the front panel  536   c , which can be varied in various embodiments of the cover assembly. In the preferred embodiment shown in  FIG. 1 , the top surface  537   d  of the spacer panel  536   d  will generally reside at an angle of about 90 degrees to the top surface  537   c  of the front panel  536   c.    
     Referring now also to  FIGS. 20A-20B , the length  539   a  of the rear panel  536   a  is preferably somewhat smaller than the length  539   b  of the middle panel  536   b  so that the rear panel  536   a  does not interfere with the hinges  544   b ,  544   c , support bow  550   e , or other nearby structures when the folding cover assembly  530  is folded up or unfolded. If the length  539   a  of the rear panel  536   a  is too much smaller than the length  539   b  of the middle panel  536   b , the standoffs  558  attached to the support bow  550   a  will be farther removed from the respective edges of the front panel  536   c  and the middle panel  536   b  and may not provide the desired support in the folded up configuration. More preferably, the length  539   a  of the rear panel  536   a  is from about 0.25 inch to about 8 inches smaller than the length  539   b  of the middle panel  536   b . Still more preferably, the length  539   a  of the rear panel  536   a  is from about 0.5 inch to about 2 inches smaller than the length  539   b  of the middle panel  536   b . Even more preferably, the length  539   a  of the rear panel  536   a  is about 0.75 inch smaller than the length  539   b  of the middle panel  536   b.    
     Preferably, the length  539   d  of the spacer panel  536   d  is large enough to accommodate the hinges  544   b  and  544   c  without interference with the support bow  550   e , but is preferably not significantly larger than required to accommodate the hinges  544   b ,  544   c  and support bow  550   e  so that the stored profile of the folding cover assembly  530  is minimized, and the folded profile when the folding cover assembly  530  is folded up but remains attached to the side rails  520   a ,  520   b  as illustrated in  FIG. 10D  is minimized, which is believed to reduce any tendency for the folding cover assembly  530  to catch wind when the folding cover assembly  530  is folded up but remains attached to the side rails  520   a ,  520   b  and when the truck  2  is in motion. In some embodiments, the length  539   d  of the spacer panel  536   d  is no greater than about one-third the lengths  539   a ,  539   b ,  539   c  of the other respective panels  536   a ,  536   b ,  536   c.    
     Preferably, the length  539   b  of the middle panel  536   b  is somewhat smaller than the length  539   c  of the front panel  536   c  so that the driver or operator  8  can easily grasp the storage straps  543   a  and strap brackets  543   b , when the folding cover assembly  530  is in the folded up configuration illustrated in  FIG. 10A , to hook the strap brackets  543   b  in the bracket slots  543   c  at the front of the front panel  536   c  as described below and illustrated in  FIG. 10A-10D . If the length  539   c  of the front panel  536   c  is longer than the length  539   b  of the middle panel  536   b , the folded up configuration of the folding cover assembly  530 , as illustrated in  FIG. 10D , will cover a larger portion of the cargo box  5  so that there is a more limited opening to the cargo box  5  when the folding cover assembly  530  is folded up and secured on the truck  2  as illustrated in  FIG. 10D . More preferably, the length  539   b  of the middle panel  536   b  is from about 0.25 inch to about 6 inches smaller than the length  539   c  of the front panel  536   c . Still more preferably, the length  539   b  of the middle panel  536   b  is from about 1 inch to about 3 inches smaller than the length  539   c  of the front panel  536   c . Even more preferably, the length  539   b  of the middle panel  536   b  is about 1.733 inches smaller than the length  539   c  of the front panel  536   c.    
     Once the latches  552  at both ends of the support bow  550   a  are retracted as shown in  FIGS. 4A and 4B  and described above, the rear end of the rear panel  536   a  can be lifted up from both side rails  520   a  and  520   b , bending the hinge  544   a  as illustrated in  FIGS. 6A and 6B . As the rear panel  536   a  is lifted up, hooks  562  at the ends of the support bow  550  at the front of the rear panel  536   a  disengage from the respective catches  564 ; specifically, hook  562   a  disengages from catch  564   a  attached to side rail  520   a , and hook  562   b  disengages from catch  564   b  attached to side rail  520   b . The structure and function of the hooks  562  and catches  564  are described in further detail elsewhere herein (see, for example,  FIG. 19A ). 
     The rear panel  536   a  is rotated further, onto the middle panel  536   b  as illustrated in  FIGS. 7A and 7B . At this point, the middle panel  536   b  can be lifted from the side rails  520   a  and  520   b , with the middle panel  536   b  (together with the rear panel  536   a  which is folded onto the middle panel  536   b ) pivoting upwards and frontwards, bending the hinge  544   b . A portion of the folding cover assembly  530  in schematic cross section view similar to the views of  FIGS. 5A and 5B  is illustrated in  FIG. 7A , which shows the hinge  544   a  folded in the configuration of  FIGS. 7A and 7B . 
     With lifting and rotating of the middle panel  536   b  together with the rear panel  536   a  until the middle panel  536   b  is approximately vertical, the configuration is as depicted in  FIG. 8A-8B . With continued lifting and rotating of the middle panel  536   b  frontwards, the middle panel  536   b  together with the rear panel  536   a  rotates frontwards towards the front panel  536   c . Preferably, the folding cover assembly  530  includes standoffs  558 , located on the underside  538   a  of the rear panel  536   c . The standoffs  558  can be attached to the bottom side of the rear panel  536   a  or attached to other structures such as support bows  550  or handles  559 ; in the example illustrated in  FIGS. 8A-8E , there are four standoffs  558 , two of which are attached to each of two sidebars or handles  559  on the underside  538   a  of the rear panel  536   c . The standoffs  558  are preferably located so that two are proximate the front edge  541   b  of the rear panel  536   a , and two are proximate the rear edge  541   c  of the rear panel  536   a . The standoffs  558 , and a preferred attachment of the standoffs  558  to the handles  559 , are described further below, including with reference to  FIGS. 14A-14C . Through the folding and rotating of the middle panel  536   b  and the rear panel  536   a  as just described, the standoffs  558  proximate the rear edge  541   c  of the rear panel  536   a  contact the top surface  537   c  of the front panel  36   c  as shown in  FIG. 8C . The standoffs  558  help to maintain a spaced relationship between the rear panel  536   a  and the front panel  536   c . With continued rotating of the middle panel  536   b  (together with the front panel  536   a ) the hinge  544   c  bends and the spacer panel  536   d  lifts off the side rails  520   a  and  520   b  as illustrated in  FIG. 8D . With continued rotating of the middle panel  536   b  frontwards, together with the rear panel  536   a  and the spacer panel  536   d , and pivoting and sliding of the standoffs  558 , the middle panel  536   b , the rear panel  536   a , and the spacer panel  536   d  rotate progressively farther frontwards towards the front panel  536   c , as illustrated in  FIG. 8E , until the standoffs  558  all contact the front panel  536   c  ( FIG. 9A ). During this folding of the folding cover assembly  530 , the hinges  544   b  and  544   c  flex as the middle panel  536   b , the rear panel  536   a , and the spacer panel  536   d  rotate towards the front panel  536   c  as schematically illustrated in  FIGS. 8F and 10E . Depending on forces applied by the driver or other operator  8 , the hinges  544   b  and  544   c  can flex to pass through various increasing or decreasing angles. Most commonly, however, the angles will vary in the following manner. Referring to  FIGS. 8A, 8C-8E, and 10D , during the folding up of the folding cover assembly  530 , the angle A between the middle panel  536   b  and the spacer panel  536   d  (which is about 180 degrees before beginning the folding up of the middle panel  536   b  onto the front panel  536   c , as in the configuration illustrated in  FIG. 7A ) initially decreases to angle A 1  which is about 90 degrees as shown in  FIG. 8A , then decreases past 90 degrees to angle A 2  at which point the standoffs  558  contact the top surface  537   c  of the front panel  536   c  as shown in  FIG. 8C ; angle A 2  may be about 35 degrees, but may be somewhat larger or smaller than about 35 degrees depending on the standoff distance  561   a  ( FIG. 14C ) and a setback distance  561   b  ( FIG. 10D ) between the standoff  558  proximate the rear edge  541   c  of the rear panel  536   a  and the rear edge  541   c  of the rear panel  536   a , and also depending on the relative lengths  539   a  and  539   b  of the rear panel  536   a  and the middle panel  536   b , respectively. Angle B between the spacer panel  536   d  and the front panel  536   c  (which is about 180 degrees before beginning the folding up of the folding cover assembly  530 , as in the configuration illustrated in  FIG. 7A ) is shown as angle B 1  in the configuration of  FIG. 8A  as about 180 degrees, and is shown as angle B 2  in the configuration of  FIG. 8C , preferably remaining at about 180 degrees until the standoffs  558  contact the top surface  537   c  of the front panel  536   c  as shown in  FIG. 8C . Angle C between the rear panel  536   b  and the front panel  536   c  (which is about 180 degrees before beginning the folding up of the folding cover assembly  530 , as in the configuration illustrated in  FIG. 7A ) initially decreases to angle C 1  which is about 90 degrees as shown in  FIG. 8A , then decreases past 90 degrees to angle C 2  at which point the standoffs  558  contact the top surface  537   c  of the front panel  536   c  as shown in  FIG. 8C . With continued rotation of the rear panel  536   a  and middle panel  536   b  and spacer panel  536   d , depending on the forces and manipulations applied by the driver or operator  8 , the angle A may remain about the same or may increase again as the angle B begins to decrease and the angle C continues to decrease, as shown as angles A 3 , B 3 , and C 3  in  FIG. 8D . With still continued rotation of the rear panel  536   a  and middle panel  536   b  and spacer panel  536   d , the angles A and B continue to approach about 90 degrees as the angle C continues to approach zero degrees as shown as angles A 4 , B 4 , and C 4  in  FIG. 8E . When the folding cover assembly  530  is completely folded, the angles A and B are preferably about 90 degrees and the angle C is preferably about zero degrees, as shown as angles A 5 , B 5  and C 5  in  FIG. 10D , with the rear panel  536   a , the middle panel  536   b , and the front panel  536   c  being approximately parallel to each other, and the spacer panel  536   d  approximately vertical, oriented at about 90 degrees with respect to the panels  536   a ,  536   b , and  536   d.    
     As the folding cover assembly  530  is folded up, the angle C between the rear panel  536   a  and the front panel  536   c  decreases towards about zero degrees, passing through the configurations depicted in  FIGS. 8C-8E . For embodiments in which the folded configuration of the folding cover assembly  530  has the rear panel  536   a  folded so that it is parallel to the front panel  536   c , the approximate relationship between the angles A, B, and C is believed to be given by the equation (angle C)=(angle A)+(angle B)−(180 degrees). 
     At this point, as illustrated in  FIGS. 9A, 9B, and 10A , the folding cover assembly  530  is folded up, but is still attached to the side rails  520   a  and  520   b , with the latches  552   c  and  552   d  (proximate the ends of the support bow  550   f ) engaged with the side rail lip  524  of the side rails  520   a  and  520   b , respectively, and the hooks  562   e  and  652   f  proximate ends of the support bow  550   g  engaged with the catches  564   e  and  564   f , respectively, as illustrated in  FIGS. 10C-11A . Preferably, the containment bracket or anchor socket  525   a  is affixed to the side rail  520   a  (see for example  FIGS. 2E and 9B ), and a mirror-image anchor socket  525   b  is affixed to side rail  520   b  (see for example  FIG. 11A ). The anchor sockets or containment brackets  525   a  and  525   b  keep the engaging portion  553   b  of the latches  552  proximate each end of the support bow  550   g  in a desired location along the side rail lip  524  of the side rails  520   a  and  520   b  and thereby aid in positioning the folding cover assembly  530  in a desired alignment with respect to the cargo box  5  when the engaging portion  553   b  of the latches  552  at each end of the support bow  550   g  are engaged with the side rail lip  524  of the side rails  520   a  and  520   b.    
     Referring now to  FIGS. 10A-10D , bundling means such as bungee cords or storage straps  543   a  can be utilized to fix the folding cover assembly  530  in the folded configuration; other straps, buckles, or hooks can be utilized as bundling means.  FIGS. 10A-10D  show a preferred embodiment, in which two elastic storage straps  543   a  are provided, one towards either side of the middle panel  536   b , for securing the folding cover assembly  530  in a folded configuration. Preferably, strap brackets  543   b  are provided for each storage strap  543   a , for hooking the storage straps  543   a  to the front panel  536   c ; the strap brackets  543   b  are preferably formed of a strong polymer such as a polyamide, although other materials, including composites and metals, can be used. More preferably, the strap brackets  543   b  are formed of nylon. Preferably, bracket slots  543   c  are provided in the front panel  536   c , and accommodate the strap brackets  543   b . The strap brackets  543   b  are attached to or captured on the storage straps  543   a , and the strap brackets  543   b  hook to the bracket slots  543   c  in the front panel  536   c  to secure the folding cover assembly  530  in the folded configuration when desired. In the front perspective view of  FIG. 10B  of the folded folding cover assembly  530 , a storage strap  543   a  is hooked to the front panel  536   c  with a strap bracket  543   b . Also illustrated on  FIG. 10B  are support bows including support bows  550   b ,  550   c ,  550   d , and  550   g , swing latches  562   b ,  562   d , and  562   f , standoff  558 , protective pad  558   a , and protective film  574 .  FIG. 10C  is a front view which illustrates a storage strap  543   a  near each side of the middle panel  536   b  which is hooked to the front panel  536   c  with corresponding strap brackets  543   b  to secure the folded folding cover assembly  530  in a folded configuration as shown.  FIG. 10D  shows a side view of this folded configuration of the folding cover assembly  530 , with the rear panel  536   a  secured to the front panel  536   c . The folding cover assembly  530  can be left in this folded configuration, as illustrated in  FIG. 10D , covering only the front portion of the cargo box  5 . 
     The protective film(s)  574  is preferably located on the top surface  537   c  of the front panel  536   c  so that the protective film  574  is aligned with the respective standoff  558  as illustrated in  FIGS. 9A, 10, and 10B , which illustrate the folding tonneau cover assembly  530  folded up. When the protective film  574  is located as shown between the standoff  558  and the top surface  537   c  of the front panel  536   c , damage to the top surface  537   c  by contact and abrasion by the protective pad  558   a  is minimized. When traveling, the folding tonneau cover assembly  530  may be in the folded up configuration such as illustrated in  FIG. 10B , with the strap bracket  543   b  of each storage strap  543   a  engaged with the bracket slot  543   c  as illustrated. 
     The folding cover assembly  530 , folded up and bundled and left secured to the side rails  520   a  and  520   b  in the configuration of  FIGS. 10B-10D  is illustrated in a rear perspective view, viewed from slightly below and to the driver&#39;s side of the folding tonneau cover apparatus in  FIG. 11A . As state above, the cord guides  555  preferably include clip cord guides  555   a  and retainer cord guides  555   b ; the clip cord guides  555   a  and retainer cord guides  555   b  are further illustrated in  FIG. 11B . The truck can be driven with the folding cover assembly  530  in this folded up configuration if desired. 
     Alternatively, if it is desired to remove the folding cover assembly  530  to leave the cargo box  5  completely uncovered, the folding cover assembly  530  can be removed as follows. As illustrated in  FIG. 11A  the release cord  554   b  is accessible and can easily be grasped by a driver or other operator  8 . Pulling on the release cord  554   b  will retract the latches  552  at the ends of the support bow  550   f  against the force of the biasing members or springs  556 , similar to the way in which pulling on the release cord  554   a  retracts the latches  552  at the ends of the support bow  550   a  as illustrated in  FIG. 4B . Typically, the release cord  554   b  will be pulled by a driver or other operator  8 ; the operator  8  preferably has entered the cargo box  5  via the tailgate  6   d  to grasp the release cord  554   b . When the release cord  554   b  is pulled, the engaging portions  553   b  of the latches  552  at the ends of support bow  550   f  are retracted away from the lips side rail lips  524  of the side rails  520   a  and  520   b , releasing the latches  552  from the side rails  520   a  and  520   b , and allowing the rear portion of the front panel  536   c  to be lifted up from the side rails  20   a  and  20   b  and rotated to disengage the hooks  562   e  and  562   f  from the catches  564   e  and  564   f , respectively. In this configuration, the folded folding cover assembly  530  is free from the side rails  520   a  and  520   b  of the support frame assembly  518  and can be lifted up and off the cargo box  5  as illustrated in  FIG. 12 ; the folding cover assembly  530  can be moved away from the pickup truck  2 , or stowed in the cargo box  5  or elsewhere as desired. In this case, the top opening  6   f  of the cargo box  5  is not partially covered by the folded up folding cover assembly  530 . 
     When it is desired to replace the folding cover assembly  30  on the cargo box  5 , or to close one or more panels  36 , the various steps illustrated can be done in the reverse order, as described in further detail below in reference to  FIG. 19C . To latch the various latches  552 , however, it is not necessary to manually retract any of the release cords  554 , since the latch slide  553  has an inclined bottom surface  553   a . When the latch slide  553  contacts and is forced further towards the side rail lip  524  of the side rails  520   a  or  520   b , the inclined bottom surface  553   a  of the latch slide  553  will retract the engaging portion  553   b  to allow the engaging portion  553   b  to move past the side rail lip  524 , whereupon the spring  556  will move the engaging portion  553   b  into the secured configuration, such as illustrated in  FIG. 3B  and elsewhere herein. 
     Referring now to  FIGS. 13A-13D , the cord guides  555  are schematically illustrated. As stated above, the cord guides  555  preferably include clip cord guides  555   a  and retainer cord guides  555   b . Each clip cord guide  555   a  is preferably attached to a support bow  550  as illustrated in  FIGS. 13A-13C . The clip cord guide  555   a  preferably has a securement feature or securement portion  560   a  which is configured for attachment to the support bow  550 . The securement feature  650   a  is preferably oblong and is narrow enough to fit into the channel opening  566   c , and when aligned with the open bottom of the bow bottom portion  566   b  as illustrated in  FIG. 13A , the securement feature  650   a  can be inserted into the support bow  550  as shown in  FIG. 13B . The clip cord guide  555   a  is then rotated as indicated by the arrow on  FIG. 13B  so that the securement feature  650   a  secures the clip cord guide  555   a  to the support bow  550  as shown in  FIG. 13C . Each retainer cord guide  555   b  is preferably inserted into the open end of the support bow  550  and slid along the support bow  550  to a desired location. The release cord  554  passes between the retainer cord guide  555   b  and the support bow  550  as schematically illustrated in  FIG. 13D  so that the retainer cord guide  555   b  retains the release cord  554 . The combination of clip cord guide(s)  555   a  and retainer cord guide(s)  555   b  keep the respective release cord positioned in alignment with the latches  552  and adjacent to or within the respective support bow  550 . Note that in the schematic illustrations of  FIGS. 13A-13D , some elements are not shown, such as the adhesive  570   b  (which may include adhesive tape  571   b ), hinge  544 , hinge support flange  586 , and so forth, in order to highlight the particular features being described. The elements shown in the schematic illustrations of  FIGS. 13A-13D  are not necessarily drawn to scale. 
     Referring now to  FIGS. 14A-14C , attachment of a standoff  558  to a sidebar or handle  559  is illustrated. The standoff  558  preferably has a securement portion  560   b  which is configured for attachment to the sidebar or handle  559 . Preferably, the securement portion  560   b  preferably includes two longitudinal grooves  558   b  and  558   c  which can engage the handle  559 . The standoff  558  preferably includes an elongated projection  558   d  which can be grasped to snap the standoff  558  onto the handle  559  or to remove the standoff  558  from the handle  559 . Further, the elongated projection  558   d  is preferably angled to aid in guiding the standoff  558  into engagement with the handle  559 . Preferably, the longitudinal groove  558   b  is hooked onto the handle  559  as illustrated in  FIG. 14B , and the elongated projection  558   d  is used to aid in hooking the longitudinal groove  558   c  onto the handle  559  to secure the standoff  558  on the handle  559  as illustrated in  FIG. 14C . The dimensions of the standoff  558  and position of the standoff  558 , including the standoff distance  561   a  and the setback distance  561   b  ( FIG. 10D ) when secured to the handle  559  together determine the angle C 2  ( FIG. 8C ) at which the standoff  558  contacts the front panel  536   c  when the folding cover assembly  530  is being folded up. Preferably, a protective pad or insert or rubber foot  558   a  is attached to the end of the standoff  558  as shown; the protective pad  558   a  preferably secures to the standoff  558  by adhesive such as those described herein or other adhesive known in the art. The protective pad  558   a  serves to reduce impact or abrasion damage to the front panel  536   c  when the folding cover assembly  530  is folded up onto the front panel  536   c.    
     In this example, the length  539   d  of the spacer panel  536   d  is substantially smaller than the lengths  539   a ,  539   b ,  539   c  of the other panels  536   a ,  536   b ,  536   c  ( FIG. 2A ). The dimensions of the standoff  558  are chosen to accommodate the length  539   d  of the spacer panel  536   d , so that the front panel  536   a  and the rear panel  536   c  are preferably parallel and separated from one another in the folded configuration such as is illustrated in  FIG. 10D . The larger lengths  539   a ,  539   b ,  539   c  of panels  536   a ,  536   b ,  536   c  provide for efficient coverage of the cargo box  5 , while the smaller length  539   d  of the spacer panel  536   d  provides for folding up of the folding cover assembly  530  to a convenient folded size, while providing space for the various hinges  544 , support bows  550 , and other components within the folded-up folding cover assembly  530 . As the spacer panel  536   d , the middle panel  536   b , and the rear panel  536   a  are folded together onto the front panel  536   c , the standoff  558  the rear end of each of the handles  559  attached to the bottom surface  538   a  of the rear panel  536   a  contacts the front panel  536   c  and provides a pivot point and sliding support to aid in orienting the panels  536  in the folded configuration as shown. Preferably, the standoff  558  is long enough to ensure contact between the protective pad  558   a  and the top surface  537   c  of the panel  536   c  in order to minimize movement and stress on the hinges  544   b  and  544   c  and to minimize any damage due to abrasion between the protective pad  558   a  and the top surface  537   c  of the panel  536   c . Preferably, the standoff  558  is short enough to avoid undue stress on the panel  536   c  and the hinges  544   b  and  544   c  when the folding cover assembly  530  is folded up as illustrated in  FIGS. 10A-10D . 
     Referring to  FIGS. 15A-15C , the perimeter seal  534  provides a seal against the entry of water, dust, or other debris into the cargo box  5  around the perimeter of the folding cover assembly  530 . The perimeter seal  534  can also adapt to irregularities in the fit between the folding cover assembly  530  and the sidewalls  6   a ,  6   b , front wall  6   c , and tailgate  6   d  of the cargo box  5 . The perimeter seal  534  is preferably attached to the panels  536  with adhesive such as adhesive  570   a ,  570   b  described above, although other attachment mechanisms can be used to secure the perimeter seal  534  to the underside  538  of the respective panel  536 , such as those described herein for attachment of the flexible hinge  544  or the support bows  550  or the handle  559  to the panels  536 .  FIG. 15A  schematically illustrates one example perimeter seal  534   a  having D-shaped cross section as shown. Preferably, adhesive  535  is used to secure the perimeter seal  534  to the panels  536 ; although other types of adhesive, such as pressure-activated, heat-activated, UV-activated, chemical-reaction-cure, or other adhesives that are known in the art, can be used, preferably adhesive  535  is an adhesive such as the previously described adhesives  570   a ,  570   b ,  571   a ,  571   b .  FIG. 15B  schematically illustrates another example perimeter seal  534   b  having a perimeter seal lip  534   d ; perimeter seal lip  534   d  can aid in alignment of the perimeter seal  534  at the edge of the panel  536 , and can also provide some protection when manipulating panel  536  so that injury from contact with any narrow or sharp edges of the panel  536  is avoided.  FIG. 15C  schematically illustrates another example perimeter seal  534   c  having an extended perimeter seal flange  534   e  which provides similar advantages as the perimeter seal lip  534   d  but also extends a short distance over the top surface of the panel  536 ; the example perimeter seal  534   c  has an open cross section with an extended sealing feature  534   f . Different configurations of the perimeter seal  534  can be used in different portions of the folding cover assembly  530 . For example, the perimeter seal  534   a  could be used along the front of the front panel  536   c  to seal against the front wall  6   c  of the cargo box  5 , while the perimeter seal  534   b  could be used along the sides of the panels  536  to seal against the sidewalls  6   a ,  6   b  (or sidewall cap  6   e , if the truck  2  is so equipped), while the perimeter seal  534   c  could be used along the rear of the rear panel  536   a  to seal against the tailgate  6   d . Further example perimeter seals include perimeter seal  534   g , schematically illustrated in  FIG. 15D , which has an open cross section similar to perimeter seal  534   c  but without an extended lip or flange.  FIG. 15E  illustrates an example perimeter seal  534   h  which is similar to perimeter seal  534   b  but also includes an extended perimeter seal flange similar to that shown in  FIG. 15C .  FIG. 15F  shows an edge guard  534   i  for attachment at an exposed edge of a panel  536  but with minimal intrusion along the top surface  537  or the bottom surface or underside  538  of the respective panel  536  (corresponding to the top surface  532   a  or the bottom surface  532   b , respectively, of the folding cover assembly  530 ); edge guard  534   i  can be used for protection at the rear edge of the rear panel  536   a , for example. Edge guard  534   i  is preferably secured by an interference fit with the respective panel  536 ; alternatively, edge guard  534   i  can be secured to the respective panel  536  by an adhesive such as adhesive  535  illustrated in  FIGS. 15A-15E, 15G-15H .  FIG. 15G  schematically illustrates a perimeter seal  534   j  similar to perimeter seal  534   g  of  FIG. 15D  but having an extended sealing feature  534   f  somewhat shorter than the perimeter seal of  FIG. 15D , as shown. A preferred perimeter seal  534   k  is schematically illustrated in  FIG. 15H . The perimeter seal  534   k  preferably includes extended sealing feature  534   f  and a thick back portion  534   m , with the adhesive  535  located at the thick back portion  534   m  for securing the perimeter seal  534   k  to the respective panel(s)  536 . The perimeter seal  534  can be formed into a bend at the corners of the cargo box  5 , or separate segments of the perimeter seal  534  can be applied near each of the driver&#39;s side, passenger side, front side, and rear side of the folding cover apparatus  530 , preferably cut to meet at a 45 degree angle to provide an essentially continuous perimeter seal around the perimeter. In a similar manner, differing configurations of perimeter seal  534 , such as various perimeter seals  534   a ,  534   b ,  534   c ,  534   g ,  534   h ,  534   j , and  534   k  described herein can be used along different portions of the perimeter, preferably cut to meet in close approximation and thereby providing an essentially continuous perimeter seal around the perimeter but with differing seal configurations at different portions of the perimeter. An edge guard such as edge guard  534   i  can be used to protect against damage or injury from the edge of the panel  536 . Preferably, the perimeter seal  534  is arranged to provide an essentially continuous seal around the perimeter of the cargo box  5 , and in addition, the rear edge of the rear panel  536   a  preferably has an edge guard  534   i . Thus, some portions of the folding cover assembly  530  have perimeter seals  534  (which may include perimeter seals  534   a ,  534   b ,  534   c ,  534   g ,  534   h ,  534   j ,  534   k , for example) in addition to edge guard  534   i . Alternatively, the extended perimeter seal flange  534   e  can be incorporated into the perimeter seal  534  so that a separate edge guard  534   i  is not required. Various perimeter seals and edge guards made of polymeric material, as shown in  FIGS. 15A-15H , are available from Lakeview Industries, Chaska, Minn. Preferably, the folding cover assembly  530  described herein includes a perimeter seal such as a perimeter seal disclosed herein, such as perimeter seal  534 ,  534   a ,  534   b ,  534   c ,  534   g ,  534   h ,  534   j ,  534   k . In some views in the drawings, the perimeter seal is not shown for clarity of illustration. The folding cover assembly  530  preferably includes the perimeter seal  534   a  along each of the sidewalls  6   a  and  6   b , and the perimeter seal  534   k  along the front wall  6   c , and the perimeter seal  534   h  along the rear portion (proximate the tailgate  6   d ). 
     The panels  536  preferably include sheet metal, although a rigid and tough polymer sheet can be used. In particular, lightweight and strong metal alloys, such as aluminum alloys, are preferred. The panels  536  are preferably relatively rigid as compared to the hinges  544 , so that when the folding cover assembly  530  is folded up as described herein, the panels  536  remain relatively flat, while the hinges  544  can flex to fold up the folding cover assembly  530 . Preferably, the panels  536  are from about 0.020 inches to about 0.200 inches thick. More preferably, the panel material is 5052-T34 rolled aluminum alloy from Aleris Inc., Cleveland, Ohio, which has a thickness of about 0.063 inches thick and is coated on the top with a Krystal Kote™ polyester paint system coating from Valspar Sourcing, Inc., Minneapolis, Minn. and on the bottom with a clear epoxy coating while it is in the factory. The rolled aluminum alloy is manufactured into a coil of rolled aluminum. Once cooled, the coil is unrolled and separately coated on the top and the bottom surfaces of the aluminum material, heat treated and recoiled for delivery to a material handler or to the buyer. The coated panel material is then unrolled and panels are cut using a laser cutting machine or such other equipment that allows the panels to be effectively cut to desired size and shape specifications. The thickness of the respective panels is minimized to limit the weight of the respective panels and the cost of the materials, but it the panels are too thin they will be subject to deformation between supporting structures. The panel material will preferably have a thickness of from about 0.020 inches to about 0.200 inches, more preferably from about 0.030 inches to about 0.126 inches, still more preferably from about 0.040 inches to about 0.100 inches, even more preferably from about 0.050 inches to about 0.080 inches, and most preferably about 0.063 inches. Other protective coatings can be used, such as urethane coatings, which may include UV protection. Protective coatings may be obtained, for example, from BASF (Wyandotte, Mich.) and Glasteel (Moscow, Tenn.). One preferred protective coating is BASF Elastocoat R85A92 WHT. Other rigid panels such as fiber reinforced plastic panels, such as can be obtained from Polser FRP Panels, Inc. (Izmir, Turkey). 
     This most preferred thickness was selected for a number of reasons including strength and process limitations. For the preferred coating described above, 0.063 inches is the thickest size that is believed to be presently available from manufacturers of the product. Since this was the thickest material that could be obtained with the preferred coating, the rigid alloy 5052-T34 with the aforementioned coatings was selected from a number of other materials having a number of other sizes. The inventors have determined that using an aluminum alloy allows the cover to be both light weight and rigid. The 5052-T34 material was chosen because it allows the cover to be strong and resistant to permanent deflections under static loads, denting, bending and long term abuse. The thickness also creates limitations if it is too thick because the panels  536  may interfere with one another at the hinge locations when the folding tonneau cover  530  is folded up and can therefore add a lot of unwanted stress on the hinge flexible hinge body  545   a  or the adhesive  570   a ,  571   a  where the respective hinges  544  are attached and sealed to the adjacent panels  536 . If the panel material is too thin, the panels  536  will sag and easily deform with static loads. In alternate embodiments, other materials are used to make the panels  536  such as steel, aluminum, fiberglass, carbon fiber, ceramic, thermoset plastics, thermoplastics, HDPE, LDPE, ABS, PVC, Nylon, titanium alloy, magnesium alloy, copper, brass, stainless steel, rubber, fiber-reinforced or glass-containing polymeric materials and the like. 
     As noted, the preferred coatings on the panels  536  are a Kyrstal Kote™ polyester paint system from Valspar, preferably a black polyester base coat with a clear texture top coat on the top surface  537  and a clear epoxy coating on the underside or bottom surface  538  of the panels  536 . Other coatings that could be used in alternate embodiments include acrylic paints, polyester paints, epoxy coatings, galvanized coatings, zinc plating, anodizing, other plating systems and the like. Alternative coatings include any combination of the above-mentioned coatings on either the top or the bottom sides of the panels  536 . The texture on the top surface  537 , bottom surface  538  of the respective panels  536  can be smooth, brushed, embossed, dented, sandblasted, rolled, waved and the like. Although a black top surface is preferred on the panels  536 , coating including others colors that are well known in the art may also be applied on the top surfaces  537  and the bottom surfaces  538  of the respective panels  536  in alternative embodiments. It will be appreciated that the coating on the respective surfaces are desirable both aesthetically and functionally to enable the respective surfaces to hold up over time in harsh environments. 
     Now referring also to  FIGS. 16A-16K , the support bows  550  are preferably metal channels, more preferably extruded aluminum, although a strong thermoplastic or other polymeric material that is either molded or extruded could be used. Preferably, the support bows  550   b - 550   f  have a slight bend or bow, and are curved so that they are downwardly concave or concave down as shown (deflection distance d is exaggerated in some views for clarity of illustration). When the panels  536  are attached to the bent support bows  550   b - 550   f , the panels  536  deflect and take on a corresponding slight bend or bow, except for the rear portion of the rear panel  536   a  and the front portion of the front panel  536   c , which are preferably flat so that they approximate the shape of the tailgate  6   d  and the front wall  6   c  of the cargo box  5 . For this reason, the support bows  550   a  and  550   g  are preferably straight. The resulting slight bow in the folding cover assembly  530  aids in shedding of water or debris from the folding cover assembly  530 . Although the support bows  550  preferably include extruded channel, as long as the upper surface  566   d  of the support bow  550  has this downward curvature, the curvature will be imposed upon the panels  536  in the manner described. An example support bow  550  which is straight is schematically illustrated in  FIG. 16A ; the support bow  550   a  at the rear of the rear panel  536   a  and support bow  550   g  at the front of the front panel  536   c  are preferably straight. Support bows  550  which are curved or bent are schematically illustrated in  FIGS. 16B, 16C, 16E, 16G, 16I, and 16K ; the support bows  550   b ,  550   c ,  550   d ,  550   e , and  550   f  are preferably curved. Such curved support bows  550  are referenced as  550 ′ in  FIGS. 16B, 16C, and 16E, 550   a ′ in  FIG. 16G, 550   d ′,  550   f ′ in  FIG. 16I, and 550   e ′ in  FIG. 16K , to distinguish them from the straight support bows  550 ,  550   a ,  550   d ,  550   f , and  550   e , respectively, in  FIGS. 16A, 16F, and 16H, and 16J . The upper surface  566   d  of each respective support bow  550 ′,  550   a ′,  550   d ′,  550   f ′ is preferably curved so that the upper surface  566   d  at the ends of the respective support bow  550  are a deflection distance d lower than a highest extent of the upper surface  566   d  of the support bow  550  as shown (between the ends of the support bow  550 , but preferably at the center portion of the support bow  550  as shown in  FIG. 16B ). The deflection distance d is preferably between about zero and about 1 inch; more preferably, the deflection distance d is preferably between about 1/64th inch and about ½ inch; still more preferably, the deflection distance d is about ⅛ inch. These example approximate deflection distances are for a typical cargo box  5  of a typical pickup truck  2 ; for wider or narrower cargo boxes, the length of the respective panels  536  and the respective support bows  50  may be longer or shorter, and the deflection distance d is preferably correspondingly larger or smaller, in order to provide a similar function in aiding the run-off of water or other debris from the panels  536 . Currently, for example, most common pickup truck cargo boxes are from about 3.5 feet to about 6 feet in width; the deflection distance is preferably correspondingly smaller or larger when the folding cover assembly is sized to cover a cargo box which is narrower than about 3.5 feet or wider than about 6 feet, respectively. The inventors have found that for most common trucks, a deflection distance d which is about 1/16 inch or less typically does not provide the preferred water run-off. The inventors have also found that a deflection distance d which is about 3/16 inch or more can create unwanted stress particularly in the panels  536   a  and  536   c  which preferably have one curved support bow  550  and one generally straight support bow  550  configured to approximate the shape of the tailgate  6   d  and the front wall  6   c  of the cargo box  5 . Therefore, we have found that for the typical truck cargo boxes  5  about 3.5 to about 6 feet in width, the preferred deflection distance is between about 1/16 inch and 3/16 inch. In some embodiments, support bows  550  include optional opposed support holes  574   e  in the front and rear portions of the support bow as illustrated. 
     Support bow  550   e  is shown in  FIG. 16J , which also illustrates bow main portion  584 , bow upper portion  585 , hinge support flange  586 , and flange lips  587   a  and  587   b . Similarly, curved support bow  550   e ′ is shown in  FIG. 16K , which also illustrates bow main portion  584 ′, bow upper portion  585 ′, hinge support flanges  586   a ′ and  586   b ′, and flange lips  587   a ′ and  587   b′.    
     In preferred embodiments, the support bows  550  include the bow main portion  584  including a generally C-shaped channel with the bow upper portion  585  configured for attachment to the bottom surface  538  of the respective panel  536  and oriented with the channel opening  566   c  at the bottom. Some components of the folding tonneau cover apparatus  510  preferably slide into or are attached to the support bows  550 , including the latch slides  553 , the cord guides  555 , the standoffs  558 , spring  556 , and the spring retainers  557   a . The bow end caps  565  preferably slide into the ends of the support bows  550 . 
     Some embodiments include support bows  550  that are straight, such as the support bows  550  that are schematically illustrated in  FIGS. 16F, 16H, and 16J , which include no hinge support flange  586   a ,  586   b , one hinge support flange  586   a ,  685   b , or two hinge support flanges  586   a ,  586   b , respectively. Some embodiments include support bows  550  that are curved or bent, such as the support bows  550  that are schematically illustrated in  FIGS. 16G, 16I and 16K , which include no hinge support flange  586   a ,  586   b , one hinge support flange  586   a ,  685   b , or two hinge support flanges  586   a ,  586   b , respectively. The folding cover assembly  530  preferably includes support bows  550  that are straight as support bows  550   a  and  550   g  illustrated in  FIGS. 2B, 16A, and 16F ; support bows  550   a  and  550   g  are not adjacent to a hinge  544  and therefore do not require a hinge support flange  586   a  or  586   b  ( FIGS. 16A, 16F ). The folding cover assembly  530  preferably includes support bows  550  that are curved or bent (concave down) and include a hinge support flange  586   a  located to one side of the bow main portion  584  and extending to support the hinge side portion  546   b ,  546   c  as described above and further illustrated in  FIGS. 16H and 16I . The folding cover assembly  530  more preferably includes support bows  550  that are bent and have a hinge support flange  586   a  as support bows  550   b ,  550   c ,  550   d  and  550   f  ( FIG. 2B ). Preferably, the folding cover assembly  530  includes a support bow  550  that includes two hinge support flanges  586   a  and  586   b , located on opposed sides of the bow main portion  584 , each hinge support flange  586   a ,  586   b  extending to support the hinge side portion  546   b ,  546   c  of hinge  544   b ,  544   c , as described above and further illustrated in  FIGS. 16J and 16K . The folding cover assembly  530  more preferably includes a support bow  550  that is bent and has two hinge support flanges as support bow  550   e  ( FIGS. 2B, 16K ). 
     The sidebars or handles  559  are attached to panels  536   a ,  536   b , and  536   c  near each side of each panel  536 . The sidebars  559  provide additional support along the side portions of the panels  536 . The sidebars  559  are preferably metal, although a strong polymer can be used. More preferably, the sidebars  559  are formed of aluminum. The sidebars  559  are preferably formed with recesses or other grasping features, to facilitate grasping for lifting and positioning the panels  536  during opening and closing of the folding cover assembly  530 . Preferably, the support bows  550  and the sidebars or handles  559  are elongated, so that they can provide support across the width  540  or length  539 , respectively, of the respective panel  536 . 
     Referring now to  FIGS. 17A-17B , viewed along the viewing line  17 A- 17 A in  FIG. 3A , additional details in the vicinity of the side of the spacer panel  536   d  are illustrated. These views show hinges  544   b  and  544   c , latch  552   d , and support bows  550   d ,  550   e ,  550   f , and the containment bracket  525   b . In  FIG. 17B , the middle panel  536   b  has been raised up to begin folding this portion of the folding cover assembly  530 . The hinge  544   b  is shown flexing, and the hook  562   d  is rotated and displaced from the catch  564   d  so that the spacer panel  536   d  can also be lifted up. Some elements shown elsewhere herein are not shown in  FIGS. 17A and/or 17B  to show the hinge function more clearly. 
     The hinge body  545   a  is further illustrated in  FIG. 17C , which is an isolated perspective view of the hinge body  545   a  and the adhesive  570   a , illustrating the hinge longitudinal axis  545   b , the hinge body profile  545   c  along a representative vertical front-rear section plane  597 , the hinge body upper surface  595 , the hinge body lower surface  596 , representative hinge thickness  545   d  in two locations, the central portion  546   a , the side portions  546   b ,  546   c , and the intermediate portions  546   d ,  546   e.    
     As described above in relation to the schematic illustrations in  FIGS. 5A-5B , the flexible hinge body  545   a  preferably includes more than one polymeric material such as those described herein; for example, the flexible hinge body  545   a  may include a softer or lower-durometer elastomeric polymer material  547   c  and a harder or higher-durometer elastomeric polymer material  547   d . The central portion  546   a  preferably includes the softer elastomeric polymer material  547   c , and the side portions  546   b  and  546   c , which are secured to the rigid panels  536  as stated, preferably include the harder elastomeric polymer material  547   d . In such embodiments, a transition or mixing of the materials preferably occurs in the intermediate portions  546   d  and  546   e . This arrangement preferably provides a structure with the central portion  546   a  being more flexible in bending than the intermediate portions  546   d  and  546   e  and the side portions  546   b  and  546   c , so that bending of the flexible hinge body  545   a  preferentially occurs in the central portion  546   a , although some flexing and bending can occur in other portions of the flexible hinge  544  in addition to the central portion. Embodiments of the hinge  544   a  are further illustrated in  FIGS. 18A-18F , which are schematic illustrations similar to those of  FIGS. 5A and 5B , with similar orientation as viewed from line  5 A- 5 A on  FIG. 2A . 
     A portion of the hinge body  545   a  is shown in a perspective view in  FIG. 17D  taken from the dashed rectangle  17 D shown in  FIG. 17C , which shows the hinge body profile  545   c  of the hinge body  545   a , and also showing the central portion  546   a , the side portions  546   b  and  546   c , the intermediate portions  546   d  and  546   e , more flexible polymer material  547   c , stiffer polymer material  547   d , intermediate polymer material  547   e , adhesive  570   a  and  570   b , hinge body upper surface  595 , and hinge body lower surface  596 . 
     A portion of the hinge body  545   a ′ is shown in perspective view in  FIG. 17E  which is similar to the view shown in  FIG. 17D , except that the hinge body that is shown is an alternate hinge body  545   a ′, which shows the hinge body profile  545   c ′ of the hinge body  545   a ′, and also showing the central portion  546   a ′, the side portions  546   b ′ and  546   c ′, the intermediate portions  546   d ′ and  546   e ′, hinge body polymer material  547   a ′, and double-sided adhesive tape  571   a.    
     A portion of the hinge body  545   a ′″ is shown in perspective view in  FIG. 17F  which is similar to the view shown in  FIG. 17D , except that the hinge body that is shown is an alternate hinge body  545   a ′″, which shows the hinge body profile  545   c ′″ of the hinge body  545   a ′″, and also showing the central portion  546   a ′″, the side portions  546   b ′″ and  546   c ′″, the intermediate portions  546   d ′″ and  546   e ′″, hinge body polymer material  547   a ′, and double-sided adhesive tape  571   a.    
     A portion of the hinge body profile  545   c ′″ of hinge body  545   a ′″ is shown in  FIG. 17G , in an enlarged schematic illustration similar to that shown in  FIG. 18J , which is referenced herein below, except that the hinge body  545   a , shown in  FIG. 18J , is somewhat different from that of the hinge body  545   a ′″ which allows the configuration of the partial enclosure  592  to engage the alternate hinge body  545   a ′″ in a slightly different manner wherein the panel  336  does not abut against the hinge body  545   a ′″ the same way that is shown in  FIG. 18J . 
     The hinge body  545   a ′″ is shown in a further enlargement, shown in  FIG. 17H , which is taken from the dashed circle  17 H of  FIG. 17G , which illustrates a portion of the hinge body  545   a ′″ and the partial enclosure  592  in which the hinge body is secured and also showing the gap  590  between a first point  593   a  on the lip  587   b  of the support flange  586   b  of the support bow  550  and a second point  593   b  at the lower corner of the rigid panel  536 . 
     In preferred embodiments of the present folding tonneau cover assembly  530 , the preferred hinge body  545   a ′″ will be made of a single polymeric material  547   a  having a single durometer, as shown in  FIGS. 17F, 17G, 17H, 18D, 18E and 18F  and no adhesive material will be required to secure the hinge body  545   a ′″ within the partial enclosure  592  created in part by both the bottom surface  538  of the respective rigid panel  536  and a support bow  550  secured to the bottom surface  538  of the rigid panel  536  on each side of the hinge  544  so as to secure the respective side portion  546   b ,  546   c  and intermediate portion  546   d ,  546   e  at least partially within the respective partial enclosure  592 . In other embodiments disclosed herein, various ways of incorporating adhesive materials into the folding tonneau cover assembly  540  are used to secure the respective hinge body  545   a  within the respective partial enclosure  592 , but with this embodiment of the hinge body  545   a ′″ it will be appreciated that the partial enclosure  592  is sufficient to retain the hinge body  545   a ′″ without having a need for adhesive material to secure the hinge body  545   a ′″ within the partial enclosure  592 . The hinge body  592   a ′″ may also be made of multiple polymeric materials and be made of dual or multiple durometer material (not shown) and not require adhesive material for suitable securement in the partial enclosure  592  and adhesive material can, of course, be used to secure the alternate hinge body within the partial enclosure  592 . 
     Referring now further to  FIGS. 17F, 17G and 17H , the partial enclosure  592  on each side of the hinge body  545   a ′″ is constructed and arranged to retain one of the respective side portions  546   b ,  546   c  and the adjacent intermediate portions  546   d ,  546   e  within the partial enclosure  592  without a need for any adhesive. It will be appreciated that the lack of a need for an adhesive is especially advantageous during the assembly process and also if a need arises to remove and replace the hinge body after manufacture. The key to retaining the hinge body  545   a ′″ within the partial enclosure  592  is the limited width of a gap  590  that exists between a first point  593   a  on an inside surface of the lip  587  of the support flange  586  of the support bow or support member  550  that is secured to a bottom surface  538  of the proximate panel  536  and a second point  593   b  at the bottom corner of the adjacent rigid panel  536 . This gap  590  is constructed and arranged to be large enough to accommodate a portion of the hinge body  545   a ′″ that resides between the central portion  546   a ′″ and the respective intermediate portion  546   d ′″,  546   e ′″ to fit within the gap  590 . As shown in  FIG. 17H , the length of gap  590 , which is the same as the length of the dashed line  594 , that extends from the first point  593   a  on the inside surface of the lip  587   b  to the second point  593   b  at the lower corner of the bottom surface  538  of the rigid panel  536 . This dashed line  594 , which has the same length as the gap  590 , is longer than the line  576  that extends from the upper surface  595  of the hinge body  545   a ′″, proximate the second point  593   b , to the lower surface  596  of the hinge body  545   a ′″, proximate the first point  593   a . Lines  577   a ,  577   b , and  577   c  are each parallel to line  576  and also parallel to dashed line  594 . As can be seen, lines  577   a    577   b , and  577   c  are each successively longer in length than the line  594  and line  576 , because the width of the intermediate portion  546   d ′″ and  546   e ′″ on each side of the central portion  546   a ′″ become progressively wider or larger as the lines grow progressively further away from the gap  590  and the upper surface  595  and the lower surface  596  diverge from one another as these respective surfaces become farther away from the gap in the immediate vicinity of the intermediate portions  546   d ′″,  546   e ′″, respectively. As the respective intermediate portion  546   d ′″,  546   e ′″ descends away from the central portion  546   a ′″, the hinge thickness  545   d  of the respective intermediate portion  546   d ′″,  546   e ′″ becomes enlarged, so much so that respective intermediate portion or shoulder  546   d ′″,  546   e ′″ is restricted from passing through the gap  590  under normal conditions that generally exist during the use of such a folding tonneau cover assembly  530 . This restriction is generally believed to be sufficient to prevent the disengagement of the respective shoulders  546   d ′″,  546   e ′″ and side portions  546   b ′″,  546   c ′″ from the partial enclosure  592  under normal conditions generally experienced by truck owners. 
     The edges of the gap  590  are generally unyielding because the preferred rigid panels  536  and the preferred support bows  550  are preferably made of aluminum which is generally unyielding when a polymeric material such as the polymeric material preferably used to make the hinge bodies  545   a  of the present invention are drawing against the aluminum under great force. In most cases, the polymeric material will tear or deform before the aluminum material will bend significantly or break, but in any case, such levels of force are not generally expected under the anticipated conditions under which such tonneau cover assemblies are generally required to operate. As shown in the drawings, the thickness of the respective shoulder or intermediate portion  546   d ′″,  546   e ′″ of the hinge body  545   a ′″ becomes greater as the thickness is measured in lines  577   a ,  577   b , and  577   c , which are each of incrementally greater length than the prior line as the distance from the central portion  546   a ′″ of the hinge body  545   a ′″ increases in series:  577   a  to  577   b  to  577   c . Each of these lines are incrementally greater in length than line  575  that stretches from a point on the upper surface  595  of the hinge body proximate the second point  593   b  on the lower corner of the most proximate rigid panel  536  to a point on the lower surface  596  proximate the first point  593   a  on the lip  587  of the support flange respective  586 . Each of the lines  577   a ,  577   b ,  577   c  are parallel to line  275  and each is incrementally longer and incrementally farther away from the line  275 . Because the shoulder  546   d ′″,  546   e ′″ becomes wider or thicker as the shoulder becomes farther removed from the central portion  546   a ′″ the shoulders  546   d ′″,  546   e ′″ and the side portions  546   b ′″,  546   c ′″ of the hinge body  545   a ′″ are restricted from becoming disengaged from the partial enclosure  592  by being drawn out of the partial enclosure  592  through the gap  590 . 
     In the embodiment schematically illustrated in  FIG. 18A , the configuration is similar to that illustrated in  FIG. 5A ; the support bows  550   b  and  550   c  have hinge support flanges  586   a  and  586   b , respectively, but lack the flange lips  587   a  and  587   b  which are present in the embodiment illustrated in  FIG. 5A . In the embodiment of  FIG. 18A , the arrangement preferably includes adhesive  570   a  to secure and seal the respective side portions  546   b ,  546   c  to the bottom surface  537  of the respective rigid panels  536   a  and  536   b.    
     In the embodiment schematically illustrated in  FIG. 18B , the configuration is similar to that illustrated in  FIG. 5A , except that an alternate hinge  544 ′ is shown, having a hinge body  545   a ′ that has a single hinge body polymer material  547   a  (which preferably includes an elastomeric polymer material  547   b  and more preferably includes a thermoplastic polymer as stated above) is used throughout the central portion  546   a ′ and the side portions  546   b ′ and  546   c ′ of the flexible hinge body  545   a ′. Preferably, bending of the flexible hinge body  545   a ′ preferentially occurs in the central portion  546   a ′ based on the hinge thickness  545   d  of the central portion  546   a ′ and the side portions  546   b ′ and  546   c ′ of the flexible hinge body  545   a′.    
     In the embodiment schematically illustrated in  FIG. 18C , the configuration is similar to that illustrated in  FIG. 18B , but an alternate hinge  544 ″ is shown, having a hinge body  545   a ″ that has hinge body profile  545   c ″ that is different, having a more uniformly flat profile in the central portion  546   a ″ than in the embodiment illustrated in  FIG. 18B . 
     In the embodiment schematically illustrated in  FIG. 18D , the configuration is similar to that illustrated in  FIG. 18B , but an alternate hinge  544 ′″ is shown, having a hinge body  545   a ′″ but the adhesive  570   a  is not used at the side portions  546   b ′″ and  546   c ′″ and instead the hinge thickness  545   d  at the side portions  546   b ′″ and  546   c ′″ is such that each side portion  546   b ′″,  546   c ′″ preferably contacts both the respective hinge support flange  586   a ,  586   b  and the respective bottom surface  538  of the respective rigid panel  536  without intervening adhesive  570   a.    
     The portion of the folding cover assembly  530  illustrated in  FIG. 5A  is schematically illustrated in further detail in  FIG. 18E , which shows a portion of one of the panels  536  broken away to show the underlying structure of the hinge  544 ′″, and which shows the flexible hinge body  545   a ′″, and the central portion  546   a ′″, and illustrates the partial enclosure  592  in which a portion of the hinge body  545 ′″ is secured; 
     An enlarged view of the portion of the flexible hinge  544 ′″ shown in the encircled area labeled  18 F in  FIG. 18E  is illustrated in  FIG. 18F . A portion of the hinge body  545   a ′″ and the central portion  546   a ′″, and the lip  587  are shown, and the hinge body  545   a ′″ is partially enclosed in the partial enclosure  592 . The lip  587  has a point  593   a  closest to the panel  536 . 
     The partial enclosure  592  is illustrated in  FIG. 18G  in a further schematic perspective view similar to  FIG. 18E  but showing the structure of the partial enclosure  592  with the hinge body  545   a  shown only partially and in phantom, with the rigid panels  536  and support bows  550  shown in cooperation with one another as shown in  FIG. 18D . 
     A portion of the folding tonneau cover assembly  530  is illustrated in  FIG. 18H , which is an enlarged view providing a transverse vertical cross section of the portion of the folding tonneau cover assembly shown in  FIG. 18A , but showing the hinge body  545   a  in phantom. A portion of the folding tonneau cover assembly  530  is illustrated in  FIG. 18I  in a further enlarged view similar to that shown in  FIG. 18H , except that the hinge body  545   a  is shown in cross section and the rigid panels  536  and the support bows  550  are shown in phantom. 
     A further enlarged view of the portion of the folding tonneau cover assembly  530  shown in the dashed circle  18 J of  FIG. 18I  is illustrated in  FIG. 18J . Portions of the partial enclosure  592 , hinge  544 , hinge body  545   a , central portion  546   a , side portions  546   b  and  546   c , intermediate portions  546   d  and  546   e , hinge body profile  545   c , hinge thickness  545   d , hinge adhesive  570   a , hinge body upper surface  595 , and hinge body lower surface  596  are shown. Portions of the support bows  550  and rigid panels  536  are shown in phantom. 
     Preferably, the hinge thickness  545   d  between the hinge upper surface  595  and the hinge lower surface  596  is large enough in comparison to the gap  590  to provide a degree of securement of the flexible hinge body  545   a  so that the respective side portion  546   b ,  546   c  is retained between the hinge support flange  586   a ,  586   b  and the respective bottom surface  538   a ,  538   b  of the respective rigid panel  536   a ,  536   b . The hinge thickness  545   d  at the respective intermediate portion  546   d ,  546   e  is greater than the gap  590 , thereby reducing the possibility of the respective intermediate portion  546   d ,  546   e  passing through the gap  590  due to movements and stresses anticipated in use of the folding tonneau cover apparatus  510 . In embodiments which include the adhesive  570   a  (such as the double-sided adhesive tape  571   a , for example), the adhesive  570   a  provides further securement of the flexible hinge body  545   a  to the respective rigid panels  536 . 
     As described above, adhesive  570   a  is preferably located between each side portion  546   b ,  546   c  and the respective rigid panel  536  ( 536   a ,  536   b ,  536   c ,  536   d ) to protect against passage of debris or precipitation into the cargo box  5 ; the adhesive  570   a  can also aid in securement of the flexible hinge body  545   a  to the respective rigid panel  536 . Alternatively, the side portions  546   b ,  546   c  can fit tightly between the respective extended flange or hinge support flange  586  ( 586   a ,  586   b ) and the respective rigid panel  536 , to provide a degree of protection against passage of debris or precipitation into the cargo box  5 . The folding cover assembly  530  preferably includes support bows or channels  550  ( 550   a ,  550   b ,  550   c ,  550   d ,  550   e ,  550   f ,  550   g ) secured to the underside  538  ( 538   a ,  538   b ,  538   c ,  538   d ) of at least some of the rigid panels  536 , near the front edge  541   b  and/or the rear edge  541   c  of the respective rigid panels  536 , and which extend between the driver&#39;s side and the passenger side of the rigid panels  536 . The support bows  550  are preferably secured to the underside  538  of the respective rigid panels  536  by adhesive  570   b . In preferred embodiments, the support bows  550  include the hinge support flanges  586 . 
     The extended flanges  586  are preferably separated a short distance from the respective rigid panel  536 , so that there is a gap  590  between the hinge support flange  586  and the respective rigid panel  536 . The hinge support flange  586  and the respective rigid panel  536  form a partial enclosure  592  into which the side portions  546   b ,  546   c  extend. The hinge support flanges  586  each preferably include a raised lip  587   a ,  587   b  to further secure the flexible hinge body  545   a  to the respective rigid panel  536 . The raised lip is preferably positioned to create a restricted gap  590  between the raised lip  587   a ,  587   b  and the respective rigid panel  536 , so that the side portion  546   b ,  546   c  cannot easily slip out from the partial enclosure  592  through the gap  590 , further securing the flexible hinge body  545   a  to the respective rigid panel  536 . The intermediate portion  546   b ,  546   c  preferably has a hinge thickness  545   d  which does not permit the intermediate portion  546   b ,  546   c  to easily pass through the restricted gap  590 , further securing the flexible hinge body  445   a  to the respective rigid panel  536 . In some embodiments, the geometry of the partial enclosure  592 , gap  590 , side portion  546   b ,  546   c , and intermediate portion  546   b ,  546   c  provides a mechanical interlock to secure the flexible hinge body  545   a  to the respective rigid panel  536  without the need for adhesive or other fastening mechanism. In other embodiments, adhesive  570   a  is used to secure the flexible hinge body  545   a  to the respective rigid panel  536 ; in alternative embodiments, adhesive  570   a  is located at an interface between the flexible hinge body  545   a  and the hinge support flanges  586 , adhesive  570   a  is located at an interface between the flexible hinge body  545   a  (at the hinge body upper surface  595 ) and the bottom surface or underside  538  of the respective rigid panel  536 , or adhesive  570   a  is located both at an interface between the flexible hinge body  545   a  (at the hinge body lower surface  596 ) and the hinge support flanges  586  and at an interface between the flexible hinge body  545   a  and the bottom surface or underside  538  of the respective rigid panel  536 . In further embodiments, a mechanical interlock together with adhesive  570   a  secures the flexible hinge body  545   a  to the respective rigid panel  536 . In still further embodiments which include the flange lip  587 , the mechanical interlock includes the geometry of the intermediate portion and the geometry of the lip. 
     As stated above, the flexible hinge body  545   a  preferably includes polymer material  547   a , which more preferably includes an elastomeric polymer material  547   b . In some embodiments, a single type of elastomeric polymer material  547   b  is used in the central portion  546   a , side portions  546   b ,  546   c , and intermediate portions  546   d ,  546   e  of the flexible hinge body  545   a . In other embodiments, the flexible hinge body  545   a  includes a plurality, i.e. more than one type of polymer material  547   a , which differ in elastic properties; for example, a more flexible elastomeric polymer material  547   c  may be preferably incorporated in the central portion  546   a  and a stiffer elastomeric polymer material  547   d  may be preferably incorporated in the side portions  546   b ,  546   c . In this case, the intermediate portion  546   d ,  546   e  may include an intermediate polymer material  547   e  which may be a mixture or combination of the more flexible elastomeric polymer material  547   c  and the stiffer elastomeric polymer material  547   d , and may provide a transition from the more flexible elastomeric polymer material  547   c  to the stiffer elastomeric polymer material  547   d . In some embodiments, the flexible hinge body  545   a  includes more than one type of polymer material to provide for more optimal properties in the various portions; for example, a more flexible elastomeric polymer material  547   c  may be utilized advantageously in the central portion  546   c  to provide for bending of the flexible hinge body  545   a  when folding or unfolding the folding cover assembly  530 , while a stiffer elastomeric polymer material  547   d  may be utilized advantageously in the side portion  546   b ,  546   c  to provide for securement of the flexible hinge body  545   a  to the respective rigid panel  536 . Preferably, in embodiments which incorporate more than one type of polymer material  547   a , the flexible hinge body  545   a  is fabricated by co-extruding the more than one type of polymer material  547   a  to form the flexible hinge body  545   a  of materials which vary along the hinge body profile  545   c  but which are generally the same along the hinge longitudinal axis  545   b  of the flexible hinge body  545   a.    
     A portion of the folding tonneau cover apparatus  510  that includes the rear hinge  544   a , as indicated by the encircled area labeled  2 D,  19 A in  FIG. 2C , is further illustrated in an enlarged partial phantom view in  FIG. 19A , with the driver&#39;s-side side rail  220   a  shown in phantom and the truck  2  removed to show the underlying structure, and showing in phantom an alternate position of the same portion of the folding tonneau cover apparatus  510  in which the rear panel  536   a  has been lifted up and rotated frontward somewhat in the direction of the arrow so that the hook  562   a  is disengaged from the catch  564   a . With further rotation of the rear panel  536   a  as illustrated in  FIG. 19B , the rear panel  536   a  has been rotated completely forward onto the middle panel  536   b , and the hook  562   a  is disengaged from the catch  564   a , so the middle panel  536   b  is free to be lifted up if desired. The other hooks  562  and catches  564  described herein function in a similar manner as hook  562   a  and catch  564   a  just described. 
     When it is desired to replace the folding cover assembly  230  onto the cargo box  5  and cover the cargo box  5 , the folding cover assembly  230  can be placed onto the side rails  520  and unfolded as schematically illustrated in  FIG. 19C , beginning with (1) placing the bundled folding cover assembly  530  on the side rails  520  with the hooks  562  at the front of the front panel  536   c  aligned with the respective catches  564  on the respective side rails  520 ; (2) lowering the folding cover assembly  530  onto the side rails  520  until the latches  552  at the rear of the front panel  536   c  are engaged with the side rail lip  524  of the respective side rails  520  and the containment brackets  525   a  and  525   b . The bundled folding cover assembly  530  can be left secured in this configuration, or if it is desired to unfold the folding cover assembly  530  to cover the cargo box  5 , the strap brackets  543   b  can be disengaged from the bracket slots  543   c , and (3) the middle panel  536   b  can be rotated rearward onto the side rails  520 , with the hooks  562  at the front of the middle panel  536   b  engaging the respective catches  564 , and (4) the rear panel  536   a  can be rotated rearward onto the side rails  520 , with the hooks  562  at the front of the rear panel  536   a  engaging the respective catches  564  and the latches  552  at the rear of the rear panel  536   a  engaging with the side rail lip  524  of the respective side rails  520 . 
       FIGS. 20A-20E  are schematic illustrations of the folding tonneau cover apparatus  510  for various configurations of cargo box  5  geometries as may be found on various trucks  2 . Preferred embodiments of the folding cover assembly  530  include the rear panel  536   a , the middle panel  536   b , the front panel  536   c , and the spacer panel  536   d , as previously described. In  FIGS. 20A-20E , the overall length  533  of the folding cover assembly  530  is shown for each example, and the length  539  of each of the panels  536   a - 536   d  is indicated as  539   a - 539   d , respectively, and the width  540  of the panels  536   a - 536   d  is indicated as  540   a - 540   d , respectively, and the side angle  542  of the panels  536   a - 536   d  is indicated as  542   a - 542   d , respectively. Panels  536   a - 536   c  can have similar length  539   a - 539   c , or the length of some or all of panels  536   a - 536   c  can differ. Panel  536   d  can have a similar length  539   d  as panels  536   a - 536   c , but preferably the length  539   d  of panel  536   d  is substantially smaller than the lengths  539   a - 539   c  of panels  536   a - 536   c . Panels  536   a - 536   d  can have similar width  540 , or the width of some or all of panels  536   a - 536   d  can differ. Panels  536   a - 536   d  can have the same side angle  542 , or the side angle  542   a - 542   d  of some or all of panels  536   a - 536   d  can differ. 
       FIG. 20A  shows the folding cover assembly  530  as configured for a cargo box having angled sides; since this example folding cover assembly  530  has angled sides, the width  540  is different at the front and rear of a panel. In this example, the width  540  of the rear panel  536   a  at the rear of the rear panel  536   a  is labeled  540   a ′, to distinguish it from the width  540   a  of the rear panel  536   a  at the front of the rear panel  546   a . The width  540  of the panel  536   b  at the rear of the panel  536   b  is similar to the width  540   a  of the panel  536   a  at the front of the panel  536   a , and so forth. 
       FIG. 20B  is a schematic illustration of the folding cover assembly  530  as configured for a cargo box having parallel sides; in this example, the width  540  of each of the panels is similar.  FIG. 20C  is a schematic illustration of the folding cover assembly  530  as configured for an elongated cargo box; in this example, the overall length  533  is longer than in the example of  FIG. 20B .  FIG. 20D  is a schematic illustration of the folding cover assembly  530  as configured for a shorter cargo box; in this example, the overall length  533  is shorter than in the example of  FIG. 20B .  FIG. 20E  is a schematic illustration of the folding cover assembly  530  as configured for a cargo box with arbitrary shape; in this example, the sides of the panels  536  are angled, and the rear of the rear panel  536   a  is curved, extending a curved extension distance  539   e  in the central portion with respect to the side portions of the rear panel  536   a . The folding cover assembly  530  can be configured for a variety of other configurations of truck box  5 , with any of the panels  536   a - 536   d  configured with straight or angled or curved shapes such as those illustrated in the examples of  FIGS. 20A-20E , in various combinations. 
     Further advantages to the structure described herein of the flexible hinge  544  are illustrated in  FIGS. 21A and 21B . The hinge  544  as described herein is low profile, reducing the overall thickness, bulk, and weight of the folding cover assembly  530 . The flexible hinge  544  can tolerate some deformation, so that if adjacent panels  536  are not aligned perfectly, or are not perfectly flat, the hinge  544  can still function to allow the folding cover assembly  530  to fold without binding. The configuration disclosed herein of hinge  544  can accommodate panels  536 , some of which are preferably slightly bowed as described herein and illustrated in  FIG. 16E .  FIG. 21A  is a schematic illustration of a portion of the folding tonneau cover apparatus  510  showing a respective flexible hinge  544  interconnecting two respective adjacent panels  536 , showing bent or bowed support bows  550  creating a bending or bowing of the panels  536  attached thereto (see also  FIGS. 16B-16E ), with the bending or bowing exaggerated for illustration, with the panels  536  unfolded.  FIG. 21B  is a schematic illustration similar to that of  FIG. 21A , showing the two respective adjacent panels  536  folded up in the direction indicated by the arrow.  FIGS. 21A-21B  illustrate how the flexible hinge  544  can accommodate the folding up and unfolding of such bent or bowed panels  536 . 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.