Abstract:
An overhead frame mounted on a truck. A stationary frame is supported by vertical legs mounted to the corners of the truck bed. An elevating frame of smaller proportions rests and nests within the stationary frame, and pivots on a bolt assembly that attaches to the stationary frame. The trailing end of the stationary frame incorporates a row of rollers. A corresponding set of rollers is attached to the rising end of the elevating frame. When the elevating frame rises by means of an electric winch, the load gradually comes into contact with the rollers and is discharged by gravity onto the ground from the rear of the stationary frame. The elevating frame incorporates adjustable arms to permit mounting on existing overhead truck racks of varying sizes.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This Application claims the benefit of U.S. Provisional Application No. 60/633,254 filed Dec. 3, 2004. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable.  
       REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX  
       [0003]     Not Applicable.  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of the Invention  
         [0005]     The claimed invention is an apparatus, conversion kit, and method for automatically unloading oversized items, having a load-receiving portion that may be elevated on a pivotal axis, and permitting unloading by gravity and aided by means for reducing friction. One embodiment of the invention is a kit for converting a standard truck rack into an apparatus that automatically discharges a load from the top of the truck.  
         [0006]     2. Description of the Related Art  
         [0007]     The related art consists of devices in which the entire load-receiving portion elevates to discharge the load by means of gravity only. One example is U.S. Pat. No. 6,676,220, MistIer. In the claimed invention, only one section of the apparatus elevates, and the rearward section is stationary. Also, the claimed invention incorporates means for reducing friction at specified points after the load leaves rest position. Rollers are the preferred means of reducing friction. Rollers are described in related art, such as U.S. Pat. No. 6,467,662, LaRochelle, but the claimed invention permanently fixes rollers to an elevating frame that enables automatic unloading.  
         [0008]     Rollers are known in the related art for loading and unloading boats. U.S. Pat. No. 5,609,462, Reimer and U.S. Pat. No. 5,586,865, Springer, and U.S. Pat. No. 3,708,081, Schladenhauffen are three examples. The claimed invention contemplates rollers for unloading and not loading. In addition, the rollers are used only in combination with an elevating frame on the top of the truck, and the rollers do not make contact with the load when it is in rest position.  
         [0009]     The claimed invention permits automatic unloading without sacrificing truck bed hauling capacity. Many inventions utilize elevation means requiring a substantial amount of the interior hauling capacity of the truck bed, for example floor-mounted pistons (U.S. Pat. No. 4,126,357, Day). The claimed invention utilizes pulling means, such as a winch, to elevate only one section of the apparatus. Because only one section of the apparatus is elevated, and because the rollers reduce the friction, the power required of the pulling means is greatly reduced. Accordingly, the pulling means of the invention can be mounted in a convenient place, for example behind the rear window of the truck cab. This leaves virtually the entire truck bed available for other use.  
         [0010]     Unloading oversized items using typical elevation methods can be difficult or impossible under conditions of limited height clearance. Old elevation methods require the load-receiving platform to be elevated to a high degree of angle in order to overcome friction to the point that gravity alone will automatically discharge the load. The claimed invention solves this problem. The angle of discharge is greatly reduced because only one section of the apparatus is elevated, and gravity acts on the materials sooner because of the rollers.  
       BRIEF SUMMARY OF THE INVENTION  
       [0011]     The invention is an apparatus, conversion kit, and method for automatically unloading oversized items from a truck, such as lumber, pipe, or steel. One embodiment of the invention comprises a stationary frame and an elevating frame. The stationary frame is an overhead, rectangular, structure that is mounted to and positioned above a pickup truck. The stationary frame extends horizontally along the length of the truck from slightly beyond the tailgate to the front bumper.  
         [0012]     Within the stationary frame is an elevating frame. The elevating frame is of similar but smaller dimensions than the stationary frame and it is connected to the stationary frame at two points so that it pivots on an axis. The pivot axis is located on the stationary frame above the point of the truck where the cab meets the bed.  
         [0013]     A row of rollers, or other means for reducing friction, is attached to the rising end of the elevating frame. A rear set of rollers, or other means for reducing friction, is attached to the trailing end of the stationary frame above and behind the truck&#39;s tailgate.  
         [0014]     The elevating frame is comprised of two ends that move upward and downward about the pivoting axis. The end that is closest to the rear of the truck bed is defined as the opposing end. The opposing end of the elevating frame incorporates a steel extension defined as a flange. The flange has a hole defined as an attachment eye that accommodates means for pulling, such as a winch and cable system. A winch raises the elevating frame by pulling downward on the cable. The load, such as building materials, rests across both ends of the stationary frame and can be automatically unloaded to the rear of the truck as the elevating frame rises and the rollers gradually make full contact, independently from the stationary frame.  
         [0015]     Another embodiment of the invention is a conversion kit. The conversion kit comprises elements necessary to convert a standard truck rack, capable only of receiving and transporting a load, into an apparatus that automatically discharges the load. The conversion kit consists essentially of an adjustable elevating frame, means for raising and lowering it, and means for reducing friction. The user attaches the elevating frame to an existing stationary truck rack. The adjustable elevating frame is a union of an open frame and an adjustable extension. By adjusting the extension, the adjustable elevating frame will fit existing standard truck racks of varying sizes.  
         [0016]     The invention and the method of using it enable one person to safely and conveniently unload heavy materials like lumber. The elevating frame can be engaged when the user depresses a remote switch that operates the electric winch. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0017]      FIG. 1  is a horizontal side view of the stationary frame with the elevating frame in a pivoted position and supporting building materials ready to be unloaded.  
         [0018]      FIG. 2  is an overhead perspective view of the elevating frame in unloading position depicting the method of discharging a load.  
         [0019]      FIG. 3  is a horizontal side view of the stationary frame with the elevating frame in rest position without a load.  
         [0020]      FIG. 4  is the stationary frame with the rear rollers and one cross-member.  
         [0021]      FIG. 5  is the elevating frame with adjustable arms, pivot brackets, rollers, and flange.  
         [0022]      FIG. 6  is the elevating frame in unloading position together with a winch and cable system as the means for raising and lowering the elevating frame. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     The invention is an apparatus, conversion kit, and method for automatically unloading oversized items from a truck.  FIG. 1  is a horizontal side view of one embodiment of the invention and illustrates the best mode for carrying out the invention.  
         [0024]     The preferred embodiment is comprised essentially of a stationary frame and an elevating frame. The stationary frame is defined as a rectangular structure that is mounted to and positioned above a truck. The longer sides of the stationary frame are lateral members.  FIG. 1  shows one lateral member  1  of the stationary frame. The end of the stationary frame closest to the front of the truck is defined as the forward end. The end of the stationary frame closest to the rear of the truck is defined as the trailing end.  
         [0025]     The stationary frame is mounted on a truck by means of vertical supports  2  and diagonal struts  3 .  FIG. 3  also depicts the supports  2  and struts  3 . The diagonal struts increase the weight capacity of the stationary frame by strengthening the structure toward the rear where the items will be unloaded.  
         [0026]     The elevating frame  FIG. 1  is defined as a rectangular structure of dimensions similar to but smaller than the stationary frame. The elevating frame pivots within the stationary frame at the point where it connects to the stationary frame by means of a set of two pivot brackets  5 . The sides of the elevating frame that are parallel to the side of the truck are defined as side members  4 . The end of the elevating frame closest to the front of the truck is defined as the rising end ( 16  at  FIG. 5 ). The end of the elevating frame closest to the rear of the truck is defined as the opposing end ( 17  at  FIG. 5 ).  FIG. 1  shows the invention unloading two oversized lengths of lumber by means of the elevating frame. The elevating frame rotates on the pivot brackets  5  attached to the lateral member  1  of the stationary frame.  
         [0027]     The elevating frame pivots upward when a cable  6  is pulled downward by an electric winch  7 . See also  FIG. 6 . The winch can be operated remotely by a switch inside the cab of the truck.  
         [0028]     Use of the invention will often begin when the elevating frame is in rest position.  FIG. 3 . Building materials are loaded onto the stationary frame by hand or by forklift from the side of the truck. After being secured to the stationary frame as necessary, the invention can transport the materials from one place to another, such as a construction site.  
         [0029]      FIG. 2  shows the operation of the invention when the elevating frame is in unloading position. As the elevating frame pivots upward, the lumber will contact with a forward set of rollers  8 . The lumber is slowly and safely lifted from rest position and over a set of rear rollers  10 . The lumber will slide easily because at a certain angle the boards will make full contact with the two sets of rollers, independently from the frame.  
         [0030]     This invention is different from common overhead truck racks because of the rollers and the elevating frame. Most truck racks are static, constructed only to transport building materials or tools.  
         [0031]     Moveable truck platforms, commonly described as dump trucks, are different because they rely on gravity alone to discharge the load.  
         [0032]     Furthermore, existing lifting mechanisms are often cumbersome, occupying a substantial portion of the bed of a pickup truck. By contrast, the claimed invention permits automatic unloading without sacrificing truck bed hauling capacity.  
         [0033]     The rollers and the position of the elevating frame permit discharge of the load from a relatively low angle. This is an important advantage over dump truck racks that must be elevated to a high vertical point before gravity acts to discharge the load.  
         [0034]     Building the stationary frame is the first step in making the invention.  FIG. 4 . Steel end members defined as a forward end  11  and a trailing end  12  are welded to the longer lateral members  1  to form the stationary frame. A steel cross-member  13  is positioned near the middle of the lateral members for strength and stability. The rear set of rollers  10  are fastened to an end extension  14  and secured to the trailing end  12  of the stationary frame.  
         [0035]     Building the elevating frame is accomplished by connecting a rectangular frame of rigid metal, preferably steel, by welding the rising end  16  and the opposing end  17  to the side members  4 . One or more cross-braces  15  are positioned near the middle of the side members  4  for strength and stability.  
         [0036]     A forward set of rollers  8  is attached to the rising end of the elevating frame. Care must be taken to fasten the forward rollers  8  so that the top part of each roller is slightly below the top of the elevating frame. This will ensure that the load will not move while in transport.  
         [0037]     Guide brackets  9  are welded to the corners of the elevating frame. These serve to maintain the load in optimal position to contact the forward set of rollers  8 .  
         [0038]     A flange  21  is welded to the opposing end  17  of the elevating frame. A hole is drilled in the flange  21  defining an attachment eye to accommodate a cable  6  controlled by a winch  7  that will permit controlled movement of the elevating frame from rest position to unloading position. Rest position describes the elevating frame when it is horizontal with the truck bed, and within the same plane as the stationary frame. Unloading position describes an angle between the horizontal stationary frame and the elevating frame when it is raised sufficiently to automatically discharge a load.  
         [0039]     Another embodiment of the claimed invention is an adjustable elevating frame.  FIG. 5 . The elevating frame comprises part of a kit that may be assembled to work with existing standard truck racks of differing sizes. Attaching the adjustable elevating frame to an existing truck rack will convert a standard rack to an apparatus that will automatically unload. The method of using this embodiment of the invention is the same.  
         [0040]     A kit that will convert a standard truck rack to an apparatus that will automatically unload is believed to be unknown in the related art. One of benefits of this embodiment of the invention is that the user will not be required to dismantle an existing overhead truck rack in order to enjoy the convenience and safety of an apparatus that will automatically unload. Moreover, the components of the kit would be a cost-efficient alternative to purchasing and installing a new rack.  
         [0041]     The adjustable elevating frame is the result of the union of an open frame and an extension frame.  FIG. 5 . The open frame is defined as a three-sided framework of square tubing where the ends of the square tubing are open and capable of receiving reduced-sized square tubing defined as insertion arms  18 . The extension frame is defined as a three-sided framework of square tubing where the reduced-sized square tubes, further defined as insertion arms, are capable of being inserted into the ends of the open frame.  FIG. 5 .  
         [0042]     The open frame is constructed by welding a first square tube at a right angle to the end of a second square tube. The first square tube is the rising end  16  of the adjustable elevating frame. The second square tube is the side member  4  of the adjustable elevating frame. A third square tube is then welded to the opposite end of the second square tube, in a position parallel to the first square tube. The third square tube is the opposing end  17  of the adjustable elevating frame. A pivot bracket  5  is attached to the side member which will serve as the first of two points where the adjustable elevating frame will attach to an existing stationary rack. The completed open frame is in the shape of a rectangle absent one side. Cross-braces  15  may also be added to the open frame for strength and stability.  
         [0043]     The extension frame is constructed by welding the two insertion arms to a fourth square tube at right angles congruent with, but opposite to, the open frame.  FIG. 5 . The fourth square tube is the extension side member  20 . An extension pivot bracket  19  is attached to the extension side member  20  which will serve as the second of two points where the adjustable elevating frame will attach to an existing stationary rack.  
         [0044]     The outside dimensions of the insertion arms  18  are smaller than the inside dimensions of the ends of the open frame. When the user slides the insertion arms of the extension frame into the open ends of the open frame, the resulting unit comprises the adjustable elevating frame.  
         [0045]     The adjustable elevating frame must be fit to the existing stationary rack. The user aligns holes, either self-made or pre-drilled, through the insertion arms and the ends of the open frame. When adjusted into position, the adjustable elevating frame is tightly secured by hardware such as bolts and locknuts.  
         [0046]     The adjustable elevating frame is then attached to the existing truck rack on the pivot bracket  5  and the extension pivot bracket  19 . The conversion kit could be made available to consumers with the square tubing pre-welded and the pivot brackets attached. A forward set of rollers  8  would be attached, as well as the guide brackets  9  and flange  21 . The conversion kit could include a winch  7  and cable  6  system optimally designed to function as the means for raising and lowering the adjustable elevating frame.