Abstract:
A flexible cover system for truck and trailer beds. The cover system includes first and second frameworks. A flexible cover is suspended between the frameworks by developing tension in the cover. Tensioning force is preferably applied to the cover using tension frames connected near the ends of the cover. Such tension can be developed using tensioning winches. A cover suspension member extends between the frameworks and can be detached at one or both ends to allow better access during loading. The cover has ribs connected to the cover at spaced locations. A framework can be collapsed or otherwise repositioned on the bed to improve access for loading and unloading. The invention also includes methods for converting the cover systems between closed and retracted conditions.

Description:
TECHNICAL FIELD 
     The technical field of this invention is convertible covers which are extendible and retractable to cover the load bed of vehicles, particularly trucks and road trailers used to carry freight over highways and roadways. 
     BACKGROUND OF THE INVENTION 
     The trucking industry is a large segment of the economy and is important in carrying a very large amount of freight of various types and configurations. One common type of truck and trailer is the enclosed cargo style which typically includes a surrounding enclosure which is used to cover loads and protect them from the weather. The enclosed cargo style trucks and trailers are successful in protecting the load against weather and other hazzards in most situations; however, they are not as easily loaded as flatbed style trucks and trailers. Most enclosed cargo style trucks and trailers have rear doors which are fine for small loads, but disadvantageous when loading large and long items. For example, large equipment, structural steel, reinforcing steel, long timbers and a number of other types of loads are much easier to load from the side and without any impeding side walls. Alternatively, such loads may be easily loaded using a crane or overhead hoist which brings the load down onto the truck or trailer bed. 
     The prior art includes a number of earlier systems which employ a tarpaulin or other flexible cover to cover truck and trailer beds. These flexible cover systems are varied in their configurations. Some are designed to be convertible between open and closed positions. This provides added convenience to the trucker with regard to opening the truck or trailer for loading, and then closing the system for highway travel. Some of these convertible cover systems use one or more cables which allows the cover to be supported and slid thereon between the open and closed positions. In some the cables are difficult or numerous to remove or do not remove to allow for more convenient loading. In others the cable systems are prone to difficulty in operation. 
     More traditional methods for covering loads with tarpaulins or similar covers involve simply wrapping the load with the cover and securing the cover to the vehicle bed or the load being wrapped. In some situations the loads shift during travel due to braking, acceleration, inclines, bumps or other road movements. These shifting actions can lead to damage or destruction of the tarpaulins. Weather can then reach the load, in some cases causing costly damage which often affects both the shipper and recipient with either monetary costs or lost time associated with repair or replacement of the damaged cargo. 
     Traditional tarpaulins and many of the convertible cover systems require substantial amounts of time to properly place and secure the covers. This is time which can more economically be spent in traveling to the next location. Thus, there is a long-standing and continuing need for a cover systems for trucks and trailers which is easy to operate and can be quickly retracted or extended. There is also need for a cover system which is effective at excluding moisture and other weather from the loads being carried by trucks and trailers. 
     These and other considerations have been partially or fully addressed by the current invention which is described more fully below. Additional benefits and advantages of the current invention will either be given in the following description, or will be apparent from the nature of the invention and the description given herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are described below with reference to the accompanying drawings, which are briefly described below. 
     FIG. 1 is a side elevational view of a truck and trailer combination having a trailer fitted with a preferred version of the present invention. 
     FIG. 2 is a view similar to FIG. 1 showing the cover system of the invention being retracted. 
     FIG. 3 is a view similar to FIGS. 1 and 2 showing the cover system fully retracted and the rear framework forming a part thereof in a collapsed position. 
     FIG. 4 is a front elevational view of the trailer forming part of FIG.  1 . 
     FIG. 5 is a rear elevational view of the trailer forming part of FIG.  1 . 
     FIG. 6 is an enlarged front elevational view of a rear tension frame in isolation. The rear tension frame is part of the system of FIG.  1 . 
     FIG. 7 is a side elevational view of the rear tension frame of FIG.  6 . 
     FIG. 8 is an enlarged longitudinal section view showing a preferred construction used in the system of FIG. 1 at the point of connection between the cover, cover rib and cover hanger shown supported by a cover support cable which runs longitudinally along the center top of the cover. 
     FIG. 9 is a front elevational view, with portions shown partially removed and in sectional presentation to better detail the construction of the connection shown in FIG.  8 . 
     FIG. 10 is an enlarged side elevational view showing a number of mechanical features of the preferred cover system of FIG.  1 . 
     FIG. 11 is a bottom view showing a preferred construction of the cover used in the system of FIG.  1 . Portions have been broken away and removed for purposes of illustration. 
     FIG. 12 is a bottom view of portions of the trailer of FIG. 1 showing a preferred lower cover securement construction used in the system of FIG.  1 . 
     FIG. 13 is a partial sectional view further detailing the construction of FIG.  12 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). 
     Truck and Trailer Generally 
     FIG. 1 shows a tractor and trailer truck combination having a tractor portion  8  and a trailer portion  10 . Trailer  10  is connected to truck tractor  8  at a convention turntable hitch  11 . Trailer  10  has a trailer frame  12  which is conventional. FIG. 2 shows that the trailer frame  12  supports a trailer bed  13  which is a flatbed type load carrying structure of the trailer. 
     FIGS. 1 and 2 both show that the trailer is provided with a first or front bulkhead framework  14  which serves to help confine loads placed upon the trailer bed against forward movement. The trailer is also provided with a second or rear framework  16 . As shown, framework  16  is not in the form of a bulkhead, but can alternatively be constructed with such a bulkhead wall. The preferred construction shown for framework  16  is an open perimeter framework which has a rear opening through which people and cargo may pass, if desired. It is alternatively possible to provide the rear framework with a removable panel (not shown) which can further help to secure the cargo against weather damage or theft. 
     Flexible Cover System 
     FIG. 1 also shows trailer  10  equipped with a novel flexible cover system  20  in accordance with this invention. The various features and components of the cover system  20  will now be further described. 
     Cover system  20  includes a tarpaulin or flexible cover  15  which is advantageously a polyvinyl chloride sheet containing polyester reinforcing fibers. These types of tarpaulins or tarps are conventional in the trucking industry. Other types of tarps can also be used depending upon the type of service required. 
     The flexible cover is provided with first and second tension frames  30 . These tension frames are advantageously in the form of end frames which have the front and rear end portions of the flexible cover  15  trained about the frames  30  and secured thereto, such as by heat or adhesive welding of the cover back upon marginal portions of itself. 
     FIG. 6 shows the preferred first and second end or tension frames  30  in a preferred construction. Both tension frames are the same or substantially similar to each other. Frames  30  include a central section which extends transversely across the bed of the trailer. Frames  30  also include side legs  35  which are pivotally connected to the central section  33  at pivots  55 . 
     Tension frames  30  also have fittings  17  which are used to engage with a cover suspension member, such as cable  18 . Fittings  17  are advantageously rollers which are mounted to capture cable  18  and allow the frames  30  to be repositioned along the cable by rolling the fittings along the cable. Fittings  17  can advantageously be provided with a swivel (not illustrated) which provides added mechanical flexibility when the tension frames are being moved and swing in response to the operator&#39;s arms or other moving force. 
     Frames  30  also advantageously include a plurality of tension connection fittings, such as in the form of hooks  31 . Alternatively, the fittings  31  can be eyelets or unshaped extension (not shown). 
     Flexible cover  15  also advantageously includes a plurality of transverse ribs  44  shown best in FIGS. 8 and 11. Ribs  44  can advantageously be made of polyvinyl chloride pipe of conventional manufacture. The ribs  44  are slightly less in length than the widths of the cover and bed of the trailer. The ribs are advantageously mounted within a rib mounting pocket formed by a rib panel piece  41  which is adhered, or more preferably, heat welded to the underside of the flexible cover  15 . FIG. 8 shows in sectional presentation that the rib mounting pocket is formed between cover  15  and panel  41 . 
     FIG. 11 shows that the preferred rib mounting construction employs a longitudinal strap  42  which is advantageously a relatively strong strap, such as a woven nylon strap. Strap  42  is preferably sewn to the underside of the top panel of the cover, as indicated in FIG.  11 . Strap  42  extends beneath the pocket panel  41  and longitudinally along the length of the cover, such as along a medial or central longitudinal axis of the trailer. 
     The top or upper surface of cover  15  is also advantageously provided with a top strap  40 , best shown in FIG.  8 . Top strap  40  is also sewn to the cover  15  by the same or a different sewing operation as bottom strap  42 . Alternative constructions, such as adhesive or heat welding, may be possible but are not considered as strong as sewing. 
     The top cover panel is rendered waterproof despite the stitching used to secure the straps to the cover. This is advantageously done by adhesively, or otherwise sealingly attaching a sealing strap  43  along the underside of the cover. 
     The top strap  40  is used to support the cover by providing interrupt segments where the top strap  40  passes through a cover support or suspension hanger  19 . This hanger can be made from ultra-high molecular weight polymer materials widely used in industry for a variety of parts. FIG. 9 shows that the hanger is advantageously provided with a hanger connection aperture  46  which receives the top strap  40  therethrough. 
     Hanger  19  also is preferably provided with a cable or suspension aperture  47  through which cable  18  or other suspension member is trained. Cable  18  and aperture  47  are provided with clearance so that the hangers can be easily slid along the cable to extend and retract the cover. FIG. 1 shows the cover extended. FIG. 2 shows the cover partially retracted. FIG. 3 shows the cover fully retracted. 
     FIGS. 3 and 5 show that the cover is advantageously supported in the retracted condition by a cover support bracket or brackets  28  which are in this embodiment mounted to the front bulkhead. Alternatively, the brackets or other supports can be mounted to other parts of the framework. 
     The tension frames  30  are forced toward the front and rear frameworks  14  and  16  using a tension force application means. This is preferably accomplished using conventional strap winches  23  which receive one or more nylon or other relatively strong woven straps  22 . The straps  22  are connected to the fittings  31  at strap end fittings  34 . Fittings  31  are on the tension frames  30 . As shown there are a plurality or two connection fittings at each side of each tension frame. It is also possible to have only one such fitting or to have additional fittings. The straps  22  are trained over rollers  61  to align the direction of tension-developing force in a longitudinal direction relative to the trailer. 
     The cable  18  or other suspension member is made detachable from one or both ends at the suspension member connections  71  and  72  with the front and rear, or first and second, frameworks  14  and  16 . A suspension cable operator, in the form of a conventional manual winch  24  is used to tighten and loosen the cable  18 . Cable  18  has a detachable end fitting  21  which allows easy detachment from the rear framework so that the cable can be removed forward during loading and unloading of the trailer bed  13 . 
     The front and rear frameworks  14  and  16  can advantageously be provided with suitable features to allow the frameworks to be moved into multiple positions to reduce any adverse effects upon loading and unloading of the trailer. This can be done by mounting the frameworks  14  and  16  to the bed using pivotal joints  32  (see FIG.  5 ). Pivotal joints  32  allow the frameworks to be pivoted downwardly into a contracted condition after removing or displacing the stabilizing braces  26 . FIG. 3 shows the rear or second framework collapsed into the contracted position. 
     FIGS. 12 and 13 detail a preferred construction for securing the lower reaches of the cover to the bed or frame of the trailer. As shown, the detachable cover connectors  48  are in the form of resilient rubber ropes or bands which extend through grommets  93  mounted along the lower edges if the cover  15 . The connectors  48  can be stretched and placed about bed mounting hooks  50  or other suitable fittings. The use of these resilient restraints near the bottom of the cover side walls reduces wear and tear on the cover during highway travel. 
     Methods 
     The invention also includes novel methods for covering and uncovering cargo or loads supported upon a truck or trailer bed. The methods for covering a load can be defined to include loading the load or cargo upon the bed  13 . The methods can also include positioning a first cover tension frame relative to a first framework. This can be done using suitable means, such as the winches  23  or other fittings or fasteners. 
     The methods can further include moving a second cover tension frame relative to a second framework to provide tensioning of the flexible cover so as to achieve a desired tension in the flexible cover between the first and second cover tension frames. 
     The methods can further include securing or attaching lower reaches of the flexible cover to the bed at a plurality of positions, such as at resilient members  48  to fitting  50  of the trailer. 
     The methods can further include expanding or moving one or both of the frameworks  14  and  16  from a contracted condition, such as shown in the rear of FIG. 3, to an expanded condition, such as shown in FIG.  2 . This can be accomplished by bracing the framework, such as by using the brace members  26  which can be detachably mounted to trailer bed  13  at brace fittings  27 . FIGS. 3 and 2 show that the rear framework  16  is also expanded by pivoting the framework about the pivot connections  32  into the upright condition and then securing the framework into the braced upright condition. Similar action can be performed to the front framework if desired in particular circumstances. 
     The invention further includes novel methods for uncovering a flexible cover from over a load positioned upon a bed of a truck or trailer. The novel methods preferably include detaching lower reaches of the flexible cover from the bed, such as by detaching the resilient members  48  from the trailer bed fittings  50 . This can be done by stretching or deforming the members  48  and passing the loops free of the hooked fittings or other type of fittings. 
     The methods can further be defined to include moving a cover tension frame relative to a framework to release tension existing in the flexible cover as tensioned between first and second tension frames. Thereafter the operator performs by retracting the flexible cover by moving the cover along the suspension member, such as cable  18 . This can be done by rolling fitting  17  along the cable or other supporting member. 
     The methods can also include contracting at least one framework, such as frameworks  14  or  16  into a contracted condition, such as shown in FIG. 3, from the expanded condition shown in FIG.  2 . This can be done by detaching one or both ends of the brace member  26  and then pivoting the frame into the contracted condition. 
     In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.