4-bar hinge system for load bed cab-high cover adaptation to rear lift access

4-bar hinge technology is applied to forward hinged mounting of a conventional cab high cover on a pickup truck load bed, so that the cover moves clear of the vehicle cab when raised to provide improved loading access. The hinge system may be integrated with upper and/or lower rails intermediately attached to the cover and load bed rails used as mounting interfaces in fixed cover installations. Use of these interfaces alone for system attachment supports universal application to conventional matched cab high covers and load beds with minimal component variation between applications. Resulting component dimensions accommodate compact packaging, and therefore convenient, efficient shipping and storage of adaptation hardware. The system concept accommodates use of readily available hardware suited to processes and equipment already in use within affected industries, and facilitates capture of dimensions for optimal function within hinge and intermediate rail assemblies, thereby minimizing reliance upon installer skills.

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NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

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REFERENCE TO A SEQUENTIAL LISTING

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BACKGROUND OF THE INVENTION

The invention pertains to adaptation of cab high load bed covers used with pickup trucks to provide improved access to the load bed for loading/unloading and also to extend functions to new uses (where “cab high” is used to distinguish covers of approximately cab height, or greater, from load bed covers having a low profile, which are usually described as “tonneaus”). A major focus is upon achieving these benefits in a manner best accommodating processes broadly in use relative to conventional fixed mount cab high covers of the prior art (also referred to as “caps” and including covers having a height approximately matching vehicle cab height or greater, as distinct from low profile load bed covers usually described as tonneaus). Applicable US classifications include 296/100.1, 100.6 hinged load covers, 296/165 expansible or collapsible vehicle body, 296/176 expansible/collapsible from a first to a second configuration for camping. The disclosure describes a system which can be adapted for installation as part of a complete rear lifting load bed cover (similar to a lift-roof cover), or sold as a kit to be installed at a retail level. The system avoids or minimizes need for modification of the cap and ensures that aesthetic benefits are fully maintained. The application of an appropriately configured 4-bar hinging system, in combination with means for controlling associated functional geometric requirements independent of the installation process, overcomes key objections directed at lift-roof covers of the prior art.

(b) Description of Related Art

Enninga, U.S. Pat. No. 5,104,175, discloses an openable cover that is operable about an internally mounted, stationary pivot means disposed adjacent the inside top, forward end of the cover so that the cover may be rotated between open and closed positions with respect to the load bed. Limitations of the concept appear to include cost and complexity both in manufacturing and installation. A system is shown for attaching and rotating a conventional cab high load bed cover17to provide rear lift. The system employs hinged attachment of the cover to a frame comprising left and right side bases21,22joined by a bridge29to create a frame fixedly attached to the vehicle load bed13. Lever members27,37are attached to the frame by pivots25,35. It appears that the cover17is attached to lever members27,67and thereby pivots about pivots25,35. With this arrangement, attaching locations on the cover17must be used other than as provided by cover side wall mounting rails normally employed for fixed mounting of a cover to a vehicle load bed. This apparently requires mountings of some form to be added to the cover forward wall. Such modifications may adversely affect the future utility and value of the cover and are avoided in the present invention.

Medlin, U.S. Pat. No. 5,595,418, discloses a short/long arm system for pivotally attaching a camper shell (cab high load bed cover) to a vehicle load bed, allowing rear lift while keeping the cap upper forward edge clear of the vehicle cab. However, upper and lower arm pivots are disclosed as substantially one above the other on the cap forward wall (or adjacent to it on the side walls). These upper pivot locations appear to require a prohibitively heavy and costly form of arm construction in order to achieve levels of lateral rigidity which would provide stable positioning of the cap relative to a load bed when open and also probably present difficulty with respect to completing satisfactory installation. As in Lake U.S. Pat. No. 7,093,882, attachments at the cap forward wall appear to require techniques which prevent it from being conveniently adaptable to a variety of production caps.

Whereas Medlin discloses a large long upper arm above a large short lower arm, each arm pivoting from an upper attachment at, or adjacent to, the cap forward wall, the present invention employs relatively small short forward and long rearward arms, each pivoting from an upper attachment at, or close to, the horizontal mounting rail at the lower edge of each side wall. In Medlin, an upper arm upper pivot resides substantially vertically above a lower arm upper pivot on or proximate the cap forward wall (cap closed), whereas in the present invention arms are positioned so that the upper pivot of each arm lies substantially on, or close to, the same horizontal plane when closed, and at no time does one arm lie above the other. Medlin discloses lengths for upper and lower arms around 48 and 30 inches, respectively, which are 6 or more times longer than needed for arms in the present invention.

Technology of the prior art also includes a 4-bar hinging system used in forward hinged attachment of low profile molded unit covers (e.g. Leer model 700) to pickup load beds. However, 4-bar hinges of the prior art for low profile load bed cover applications, if applied to forward attachment of a cab high cover, provide insufficient rearward travel of the cap to maintain clearance between a truck cab and a load bed cap when raised.

Market testing of the lift-roof cover concept defined by Lake U.S. Pat. No. 7,093,882 revealed cost issues resulting from replacement of the cap forward wall with a hinged forward wall assembly and from associated complexities of addressing multiple applications of potential customer interest. Interest has been further limited by an associated loss of availability of forward window options demanded by many users of conventional caps. The present invention provides reductions in complexity of application relative to Lake U.S. Pat. No. 7,093,882 while giving up a small degree of functionality. The improvement in loading access is provided with use of readily available caps requiring minimal or no attachment modifications. The invention is simplified relative to Lake U.S. Pat. No. 7,093,882 by avoiding need for modification of the cover forward wall, thereby more easily maintaining functional robustness and supporting customer demand for pivoting, removable, or sliding forward window options.

SUMMARY OF THE INVENTION

It is an objective of the invention to provide means for adapting a conventional cab high load bed cover to allow rear lift access as installed for use, with broad application to production pickup trucks and covers. Conventional cab high covers of the prior art vary in many details of design, as do pickup truck load beds. However, almost all load beds are built with side walls including substantially horizontal surfaces along their upper longitudinal edges which may be referred to as “bed rails”. Conventional molded caps are made with surfaces along the lower edges of their walls, usually referred to as “cap rails” and matching the load bed rail surfaces for mounting thereon. In a conventional fixed mount, cab high cover (cap) installation, weather seals are normally attached between the cap rails and load bed rails. The invention provides a lift adaptation system which is also attached between the cap rails and load bed rails, thereby supporting near-universal application with little or no modification of the cap or load bed.

In one embodiment of the invention, the cap rails are used as mounting surfaces for an upper intermediate rail attached to an upper link of a 4-bar hinge assembly. The hinge assembly may also be attached at a lower link to a lower intermediate rail which is, in turn, attached to the load bed. With the addition of upper and lower intermediate rails for attachment along the length of the cap rails and load bed rails, respectively, this embodiment of the invention conveniently accommodates attachment to the rails of key components needed for control of relationships between the cap and load bed. Such components include cap lift assist means (typically gas compression struts or articulating arms carrying compression struts), side retainers (to ensure correct lateral positioning of the cap relative to the load bed when closed), pivoting fixed strut means for securely holding the cap to a fixed partly raised position when needed for transporting an over height cargo), and draw latches for conveniently drawing and securing the cap to a closed position on the load bed. With pre-assembly of such a hinge and intermediate rail system, component relationships required for optimal function may be kept independent of installer skills, ensuring reliable reproduction of desired system geometry and supporting an installation process suited to the needs of most load bed cover retailers.

Forward pivoting of cab high covers (versus low profile covers) introduces issues beyond the obvious issue of cab interference resulting from tilting of the forward wall as a cap is lifted. A cab high cover typically has greater weight than a flat cover and, to the degree that lower edges of the side walls remain structurally unsupported, flex at hinge mountings will generally be greater. Considering flex and manufacturing costs, it is desirable to keep hinge arm lengths short. In 4-bar hinge applications of the prior art for unit-molded low profile load bed covers, pivots are longitudinally spaced so that, over much of the operating range, a long rearward arm lies vertically above a short forward arm in side view and the arms are limited in rotation, so that upper pivots only rise toward perpendicular (relative to upper surface of load bed side wall) during cover opening and only fall during closing. In the present invention, longitudinal spacing of pivots is such that a short forward arm rotates “over center” and at no point during operation lies vertically below the long rearward arm.

It will be recognized by one skilled in the art to which the invention pertains that application of a load bed cover to a load bed needs to fully address the effects of dynamic vehicle operation. In particular, structural flex and associated stresses will occur. The extent and effects of such stresses were inadequately addressed in some early molded cap designs with resulting fractures in extreme use cases. Although manufacturers have, in general, greatly improved structural characteristics, caps have used fixed mountings. Most caps maintain stable dimensions but, without lateral support, some early products have shown tendencies for lower edges of the rear door opening to start spreading. It is therefore necessary that, in closed condition, cap side walls are laterally constrained at the lower edges in a manner providing equivalence to mounting of conventional fixed caps. Such constraint may be conveniently integrated into the invention as will be described. Another consideration is that some manufacturers build a front to rear taper into the load bed side walls as a styling enhancement. This affects operation of a linkage as employed in the invention, resulting in flex effects which must be accommodated in system function.

The invention will be recognized by one skilled in the art to which the invention pertains as addressing complex issues associated with adaptation of production fixed mount cab high load bed covers to rear lift access. This is accomplished with simple structures which, in combination, provide the obvious advantages of rear lift access together with numerous advantages over technology of the prior art, including:Supporting near-universal application across production pickups and cab high caps;Providing fuel economy improvement primarily due to reductions in frontal area and associated aerodynamic drag compared against on-highway use of caps exceeding cab height as means for providing improved load bed access;Retaining all the appearance, protection and security benefits provided by a conventional, fixed mount, cab high load bed cover (cap).Utilizing readily available hardware already in widespread use;Providing the benefits of rear lift access with components which may be conveniently packaged, shipped and stored as a kit at low cost;Supporting convenient adaptation to lift access of production caps already in service;Incorporating means for conveniently and effectively accommodating dimensional variations across production caps and vehicles;Avoiding need for reliance upon installer skills to ensure optimal system geometry (with use of upper and/or lower intermediate mounting rails);Incorporating means of moving cover axis of rotation rearward during lift, minimizing (at cap full open) the adverse effects of compression strut low temperature effort fall-off.Addressing structural deficiencies which may be present in some cap or pickup load bed designs relative to adaptation to lift access (with use of intermediate rails);Ensuring high levels of cover lateral stability when open, by employing forward mounted compact dual pivot arms in conjunction with rear mounted articulating arms.Facilitating use of forward compression struts in combination with rear mounted struts to a) facilitate installation and b) support improved reliability and lift effort modulation.Supporting convenient adaptation to use with various load management accessory rail systems offered by pickup truck manufacturers.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG. 1: As installed on a pickup truck10, a cab high load bed cover (cap)12is mounted behind a passenger cab14on a load bed16including side walls18fabricated so that a side wall outside vertical surface20is continuous with an upper, substantially horizontal rail surface22of the wall18. The rail surface22likewise is continuous with an inside vertical flange24joined to the rail surface22at about 90 degrees, extending downward typically one to two inches and serving to add rigidity. The inside vertical flange24is generally accessible along most of the length of the load bed16between the load bed forward wall26and rear end28. Side walls30of the cap12are joined at their lower edges31to cap structural rails32which terminate along their length at an inner edge34above the load bed flanges24and extend from a forward wall36to the cap rear wall38. The cap rails32generally match contours of the load bed rails22. In one embodiment of the invention the cap12is attached at the cap rails32to an upper intermediate rail40attached to a short/long arm (SLA) 4-bar hinge assembly42; the 4-bar hinge assembly42is in turn attached to a lower intermediate rail44, and the lower intermediate rail44is in turn attached to the inside vertical flange24of the load bed side wall18.

One embodiment of the invention employs articulating strut arms46, carrying pivotally mounted rear compression struts47, the strut arms46being pivotally attached between the upper and lower intermediate rail assemblies40,44at a rearward, fixedly attached upper pivot48and at a rearward fixedly attached lower pivot49in such a manner as to provide assist when the cap12is raised or lowered from the rear38. For the purpose of raising or lowering the cap12, a handle50is fixedly attached to the cap12in a rearward location proximate a legally required central high mounted stop light (CHMSL) unit52connected to electrical wiring54routed to the vehicle10via an articulating strut arm46. Latching means56(such as claimed and/or disclosed in Lake U.S. Pat. No. 7,093,882), attached to a cap rail32or an upper intermediate rail40, allows latching of the cap12to a closed position relative to the load bed16by engagement with the load bed16or lower intermediate rail44attached thereto. A rear door57is typically hinged to the cap12in proximity to the cap roof rear lateral edge58and provides closure of the cap rear wall38between the (left and right) cap side walls30.

Referring toFIGS. 1 and 2: The 4-bar hinge assembly42may be understood as four links60,61,62,64interconnected by pivots66,68,70,72, making up a closed linkage42of quadrilateral form. Two links64,61on opposing upper and lower sides incorporate attachment means73,74and75,76, respectively, by which major bodies may be attached. The other links, comprising a short arm60and long arm62, control relationships between links61,64and between a cap12and load bed16fixedly attached to links61,64, respectively. Geometric relationships (as installed for use) include location of upper pivots66,72for arms60,62, respectively, on or in proximity to the cap mounting rail32forming the base of each cap side wall30. The lower pivots68,70are located in proximity to the upper edges22of the load bed side walls18(where a lower edge of the side wall inside flange24may be considered in proximity to the side wall upper surface22) and are longitudinally spaced apart a distance greater than the spacing between the long arm upper and lower pivots,72,70, respectively, so that under all operating conditions a short forward arm60remains forward of the long rearward arm62. The short/forward arm60rotates “over center” (beyond a condition where a line through upper pivot66and lower pivot68of the forward arm60reaches an angle perpendicular to an upper surface22of the side wall18) so that, during later stages of opening, the short arm upper pivot66falls relative to the lower pivot68. This increases rearward movement of the forward arm upper pivot66sufficiently to support a maximum cover lift angle equivalent to that provided by 4-bar hinge systems of the prior art for low profile load bed covers, while employing a short arm length allowing minimal levels of lateral arm flex.

An upper intermediate rail40comprising one or more generally angle section extrusions77is fixedly attached toward a forward end78to a hinge system upper link64and extends rearward most of the length of the cap rail32toward fixedly attached upper pivot means48and latch means56. A lower intermediate rail44comprising one or more generally angle section extrusions79is fixedly attached to the hinge assembly lower link61and extends rearward along a load bed side wall18toward a fixedly attached strut arm lower pivot means49. The upper and lower strut arm pivot means48,49, are engaged with the articulating strut arms46, and constrain the strut arms46to a substantially vertical orientation in front or rear view when the cap12is raised.

SLA hinge geometry causes the cap instant rotational axis (defined by intersection of force lines through pivots66,68and pivots70,72of arms60and62, respectively), to move from ahead of the cap forward wall36to a location well aft of the forward wall36as the cap12is raised. Thus, vertical rear lift force (total unaided) needed to raise the cap12may exceed half cap weight when lifting from closed, but decreases toward full open. This allows rear mounted lift assist compression struts47with relatively low force value to hold the cap12fully open and expands the range of geometry which allows the cap12to also sit closed without being separately retained in that position.

Whereas open cap forward lateral stability may depend primarily on lateral control provided by the hinge forward/short arms60; rear mounted articulating arms46(as defined by Bacon, Pub. No. US2004/0084928 A1, and marketed by Bauer Products Inc. of Michigan) control cap lateral deflection of the cap rear38while supporting rear opening lift similar to lift achieved with some forward hinged low profile covers. To provide the desired improvement in rear loading access (as for drive-on loading of a garden tractor), rear height clearance is needed approaching double the head room of a typical cab high cover above a closed flat cover. Pivot arm geometry is defined primarily by need to offset tipping of the cap forward wall36toward the vehicle cab14, when raising the cap12. It will be recognized by one of ordinary skill in the art that rearward travel of the upper forward pivot66is limited by rotation of the forward/short arm60. It will also be seen that, with the forward upper pivot66located aft of the cap forward lower corner82, rearward travel may be further limited by interference of the cap forward lower corner82with the vehicle load bed16, due to downward tipping ahead of the forward arm upper pivot66. This requires the pivot66to be located close to a cap lower forward corner82.

In an embodiment of the invention employing lift assist means47mounted rearward only, when the cap12is raised at the rear38, the SLA 4-bar hinge upper link rearward attachment means73exerts force on the cap mounting rail32and, at the same time, lower link rearward attachment means76exerts opposing force on the load bed side wall inside flange24and/or lower intermediate rail44(where employed). Effects include deflection of the cap rail32and load bed rail22(plus possible bowing of hinge arms60,62). Loading of forward arms60is generally of concern only with respect to arm flex because such forces are transferred primarily via forward attachment means75and forward attachment means74, both of which are structurally well supported due to proximity to forward walls26,36.

The SLA hinge arms60,62(primarily forward/short arms60) must provide reliable lateral positioning of the cap12with minimal bowing under load. However arms60,62must flex sufficiently to accommodate lateral stacking of manufacturing and/or assembly tolerances and to a further degree in some applications where load bed side walls have tapered front to rear spacing for vehicle styling enhancement. Flex effects manifest as additional movement of the cap12toward the cab14when the cap rear38is raised, before hinge actuation causes forward cap lift-off from the load bed forward wall26. Flex effects can be reduced by addition of forward compression strut means84(as shown inFIG. 2) to apply forward lift force at forward locations88,90between the load bed16and cap12, bypassing the hinge arms60,62, so that initial load transfer through the hinge arms60,62is reduced when the cap12is raised from closed.

Manufacturing dimensional variation as well as flex under 4-bar hinge system operation can add significant lost motion in the form of forward tipping of the cap12when raised at the rear38, before SLA hinge actuation causes lift-off of the cap forward end36. This may be addressed in part via means for adjusting angle of upper or lower hinge link means64,61relative to the cap or load bed mounting rails32,22. With variability in thickness of the cap mounting rails32, adjustment of relative orientation between the SLA hinge upper link/bracket64and the cap side wall mounting rail32is needed to facilitate closed cap surface-to-surface alignment, as needed for desired seal compression. In a preferred embodiment, such adjustment may be obtained via slot vertical adjustment means86at a rearward attachment73of the hinge upper link/bracket64.

Greatest structural deflections occur in transition from zero to maximum load through the SLA hinge arms60,62when the cap12is initially raised from closed. However, with addition of forward compression struts84, force through these struts remains present even when the cap12is fully closed, so that a force transition from zero to maximum levels is avoided. The forward compression strut84extends from an upper pivot88on the 4-bar hinge upper link64and/or intermediate rail40to a lower pivot90, attached via lower pivot mounting means92to the lower intermediate rail44and/or lower link61.

In applications where cap structural rigidity is low relative to weight, use of high force rear compression struts47alone may cause high levels of flex, possibly with associated functional issues. Therefore, the use of added forward lift struts84in combination with reduced force rear struts47is likely to prove more reliable, as well as supporting improved modulation of lift effort, while also avoiding compromise of the control benefits associated with use of articulating arms46at full rearward locations. Therefore, a preferred embodiment may incorporate adjustment means86to achieve optimal cap closure, in combination with forward compression struts84to minimize loading through the arms/links60,61,62,64and pivots66,68,70,72.

Referring toFIGS. 1,2and3: Installation typically presents opportunities for error, but is simplified by use of lower intermediate angle section rails44clamped longitudinally against the vehicle load bed side wall inside flanges24, with a horizontal flange93between the load bed side wall upper surface22and cap rail32. Lower Intermediate rails44include pre-location of hinge assemblies42and rear strut arm lower pivot means49so that correct location of intermediate rails44relative to the load bed forward wall26results in automatic capture of desired hinge and lift assist system geometry. For safety, the lower intermediate rails44need to be securely attached to the vehicle load bed16. A vertical flange94of the lower intermediate rail44is clamped to a load bed side wall inside vertical flange24. Relying upon friction alone could be unreliable, given any possibility of error in applied clamp screw torque. In a typical embodiment, a minimum of three attachments on each side are used including clamps75,76,96on the lower intermediate rails44and load bed inside vertical flanges24. A clamp76has a clamping face98with a hole100engaging the projecting end102of a rivet104passing through the lower intermediate rail vertical flange94. With clamps75,76,96thereby positively engaged with a lower intermediate rail44and looped around a side wall inside flange24, each lower intermediate rail44is thereby positively retained to the load bed16. When clamp means75,76,96are tightened, flat rivet heads105are compressed against rubberized facing106adhesively attached to the lower intermediate rail44.

Referring toFIG. 3: Load bed covers are generally molded to fit on a load bed with an integrated appearance and sufficient clearance for installation of adhesive-backed strip sealing means107longitudinally installed between the load bed side wall upper rail surface22and the cap mounting rail32. Space between cap rail32and load bed side wall upper surface22allows outboard location of seal means107. The angle section lower intermediate rail horizontal flange93, being no more than compressed thickness of a cap to load bed strip seal107, may be mounted toward the inside flange24of the load bed side wall upper surface22without degrading seal function or vehicle appearance.

Referring toFIGS. 2 and 4: Hinge pivot means66,68,70,72include bolts108with shanks110passing through close fitting holes111in the hinge links61,64and arms60,62. Hexagonal heads112of the bolts108passing through the lower links61are retained in matching hexagonal holes113in the lower intermediate rail44and protrude outward against the adhesively attached rubberized facing106.

Referring toFIGS. 1,5and6: The lower edge114of a cap forward wall36forms a lateral shelf116, typically extending forward about two inches, to which strip seal means107is adhesively attached. seal means107aseals against the top surface117of the load bed forward wall26when the cap12is closed. Where a cap manufacturer incorporates a molded lip118extending downward from the cap mounting rails32and forward wall36(inside the load bed side and forward walls18,26when installed), the lip118will probably need to be locally relieved to provide clearance adjacent to the hinge assemblies42, latches56and/or strut arms46. Such material removal can generally be accomplished without compromising sealing or cap integrity.

Referring toFIG. 6: To facilitate adjustments at attachment means73,74clearance must be provided for bolt heads112at upper pivot means66,72relative to the vertical flange119of the upper intermediate rail40. When a single extrusion upper intermediate rail40is used, the required clearance may be achieved using spacing means120between the upper link64and upper intermediate arm vertical flange119at attaching means73,74.

FIG. 7illustrates an alternate method for providing bolt head clearance at upper pivot means66,72, whereby bolt head clearance results from using an angle section intermediate rail40awith a vertical flange119alocated outboard. A short upper link attaching bracket121of similar angle section is mounted toward the forward end78awith an inboard vertical flange122between, and clear of, the hinge upper pivot heads112a.

Referring toFIGS. 1,8and9: The use of an upper intermediate rail40mounted to the cap side wall mounting rail32(at each side), to which 4-bar hinge linkage upper link/bracket64, latching means56and a rear lift assist means upper pivot48are fixedly attached, provides further capture of geometric relationships similar to that provided by use of a lower intermediate rail44. Attachment of the upper intermediate rail40to the lower intermediate rail44on each side via the 4-bar hinge linkage42further defines relationships between components needing controlled geometric relationships for optimal function. Pre-assembly of these components provides a cap hinging system which may be installed between any cap and load bed of suited dimensions using an installation process which may be completed with minimal training requirements.

Upper and lower intermediate rails40,44may be shipped pre-attached to 4-bar hinge linkages42at the upper and lower links64,61, respectively, with compression struts47,84left unmounted to facilitate shipping/storage with the rails40,44folded.

Referring toFIGS. 1,4,5and8: System installation requires mounting of the upper intermediate rails40on the cap rails32with lateral spacing matched to that of the load bed side wall rails22on which the cap12will be mounted. This process is simplified where it can be first confirmed that spacing of cap rail inside edges34will correctly align with spacing of the load bed inside vertical flanges24. Longitudinal positioning is dependent upon clearance requirements for the cap forward wall lower edge114relative to the short arm60and lower intermediate rail44(or load bed side rail22) with the cap12fully open, but may be set by positioning of the upper intermediate rail forward end78relative to the cap forward wall36. With the cap12suitably supported, the upper intermediate rails40are clamped in the desired position on the cap rails32. Holes124may be drilled in the cap rails32using holes126pre-drilled in the upper intermediate rails40for guidance. The lower openings128of holes124through the cap rails32are opened up with a countersink tool and flat head countersunk machine screws130are entered into the holes124with flat heads132flush with the cap rail lower face134. Capture of the upper intermediate rail40is completed with installation of locknuts136at the upper intermediate rail horizontal flange upper surface138. (In cases where the cap rails32are fabricated from flat plate/sheet metal, pan head or suchlike fasteners may be used in place of countersunk flat head screws130and nuts136, where the head height of such fasteners remains low relative to compressed height of sealing means107).

The upper intermediate rail40may be attached to a cap rail32, as described above, in assembly with the SLA hinge linkage42and lower intermediate rail44. The lower intermediate rail44is next raised toward, and engaged with, latching means56, which are, thereby, used to hold the intermediate rail44against the cap rail32. Cap to load bed sealing means107are installed outboard of intermediate rail44along the cap rails32and cap forward wall lower face116. The cap12may then be lowered and positioned on the load bed16. After ensuring full seal contact along the load bed rails22and at the load bed forward wall26, the hinge upper link to upper intermediate rail attaching fasteners73,74are tightened to hold the adjusted alignment.

Referring toFIGS. 1,2,8and9: After positioning the cap12on the load bed16, the lower intermediate rails44are clamped to each load bed side wall upper inboard flange24via clamps75,76,96. The forward compression struts84(if part of the application) are compressed by hand and installed with the cap12lowered in order to facilitate an initial cap lift prior to installation of higher force rear compression struts47in the open condition. Latching means56are disengaged from the lower intermediate rails44and the cap12is raised and supported fully open. Rear lift struts47are installed and the cap12is again lowered. Latching means56are adjusted to engage securely with the lower intermediate rails44. Installation is completed with attachment of a central rear lift handle50and connection of CHMSL/interior light wiring54routed through an articulating tubular strut arm46.

Referring toFIGS. 1,6,9and10: Use of intermediate rail assemblies40,44facilitates various refinements. These refinements include the incorporation of side retainer means142attached to an upper intermediate rail40and designed to engage an inboard surface144of the lower intermediate rail44so that, in closed condition, the cap side wall lower edges31receive positive lateral restraint, as provided by conventional fixed cap mounting methods. A side retainer means142is shaped to include a ramped lower end150which engages an inboard edge144of the lower intermediate rail44so that the cap12is guided to a fully aligned position on the load bed16when the cap12is closed. Where spacing means120are used to provide clearance for bolt heads112at attachments73,74of the upper intermediate rail40to hinge linkage assembly42, the upper intermediate rail40will have lateral offset relative to the lower intermediate rail44. Therefore, for optimal alignment of the upper and lower intermediate rails40,44, equivalent spacing means151are then employed between the side retainer means142and an upper intermediate rail inboard face140.

Referring toFIGS. 1,8and10: Another refinement is the use of a rigid strut152pivotally attached to a lower intermediate rail44toward the rail rearward end154so that, in emergency need for increased load clearance, the rigid strut152may be rotated upward to engage fastening means156on the opposing upper intermediate rail40. With appropriate retention at fastening means156, a cap12may thereby be securely supported at a slightly raised position. It will be understood by one skilled in the art that rigid152, also fastening means156, side retainer means142, latching means56, SLA 4-bar hinge assembly42, compression struts47and articulating arms46comprise cover to load bed relationship control components and may adequately provide their respective functions while being attached to upper and/or lower intermediate rails40,44, respectively, instead of being attached directly to the cover12and/or load bed16.

Referring toFIGS. 11 and 12: Some truck manufacturers offer longitudinal, generally channel section rails158fixedly attached to the load bed side walls18immediately below the inside vertical flange24. These rails158are designed to provide secure attachment of cargo management accessories and comprise systems which are marketed with various descriptions such as “deck rail system”, “bed rail tracks”, “bed upper rails”, “slide-on bed rails”,“T channel load bars”, “utili-track channel system”. The presence of such rails158allows their use in attaching 4-bar hinge and intermediate rail assemblies160, thereby eliminating need for clamping means75,76,96of a type illustrated inFIGS. 1 and 9. Attachment of 4-bar hinge and lower intermediate rail assemblies160is facilitated by the incorporation of lower extensions162fixedly attached or integral to a lower intermediate rail164and designed for engagement with attaching means166of a type similar to those used for attaching load management accessories with which the generally channel section rails158were designed to be used.

It will be recognized by one skilled in the art that, although the presence of generally channel section cargo management system rails158facilitates use of an integrated lower intermediate rail and 4-bar hinge lower link164, the presence of such generally channel section rails (or bars)158also reduces need for a separate load carrying full length lower intermediate rail164because much of the cap system loading will be transferred more directly to load bed side wall structure168through the cargo management system rails158. Therefore, where other means can be satisfactorily employed to replace or perform the locating function of a lower intermediate rail164, rearward lift assist pivot means49and a (short) 4-bar hinge lower link61(shown inFIG. 2) may be directly attached to the load management system rail158, obviating need for a separate intermediate rail164.

There have been described and illustrated what are considered alternate embodiments of the invention. However, these specifications shall not be construed as limitations upon the scope of the invention, since it will be understood that many alternate variations may be made by one who is skilled in the art without departing from the scope of the invention as defined by the appended claims.