Abstract:
Cargo trailer kit containing pre-fabricated ready-to-assemble modular components for a cargo trailer. The cargo box is assembled from a chassis with pre-installed floor, a plurality of wall panels, and a roof panel. Wall panels are captured top and bottom in two channels, one extending around the perimeter of the chassis and one around the perimeter of the roof panel, and secured via threaded fasteners to the chassis and roof frames. Trim pieces are attached to wall panels to seal joints between abutting panels. Signal lights are incorporated into appropriate components. A pre-assembled wheel assembly and a tow assembly are included in the kit, plus a wire harness for connecting the signal lights to the tow vehicle power supply. The cargo trailer is easily assembled with general assembly tools. The cargo trailer kit allows a complete cargo trailer to be shipped in a stackable, compact bundle.

Description:
BACKGROUND INFORMATION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to field of cargo trailers. More particularly, the invention relates to a method of making and assembling a cargo trailer having a metal frame. 
         [0003]    2. Description of the Prior Art 
         [0004]    Cargo trailers are used to tow cargo or equipment behind a powered vehicle. Trailers intended to haul costly items or heavy equipment are constructed as rugged trailers, having at least a rugged metal chassis. Typically, such trailers are closed containers and, if intended to haul a particular item of cargo or equipment, they may be specially outfitted to accommodate the item in the most efficient and safest manner. Hereinafter the term “cargo trailer” shall be used to refer to enclosed trailers that have a metal chassis and are used to haul cargo or equipment. 
         [0005]    Throughout the cargo trailer industry, cargo trailers are manufactured, shipped to dealers, and sold to consumers as completely assembled units. This has disadvantages. Shipping costs are determined by the volume of the goods to be shipped. The cargo trailer as shipped is usually empty. Thus, the greatest portion of the volume being shipped is useless space and serves only to increase the cost of the shipping. 
         [0006]    The reason that cargo trailers are shipped as completely assembled units lies in the conventional method of construction. The manufacturing process begins with a steel or aluminum chassis being bolted to an axle, which is mounted on a set of wheels. Frames for the sides, front, and back panels of the trailer are then welded or otherwise attached to the chassis, and the roof then welded to the top of the frames to complete the framing for the trailer. The next step is to install wiring in the frames. After the wiring is installed, the floor is placed the chassis, exterior panels are then attached to the frames for the sides and the roof that form a box. Interior panels, and, if required, insulation are then installed on the inside of the box. Finally, exterior lights are installed and trim and fenders attached to the outer panels. Door hinges are mounted on the rear frame and door panels mounted, paneled, insulated, and trimmed. 
         [0007]    This manufacturing process is inefficient, in that multiple and very different work steps are performed at a particular area of the trailer. For example, during the assembly process, bar stock is welded together to form the chassis and the side-wall frames, wiring, exterior paneling, insulation, and interior paneling are all assembled on each side of the box. This requires that a large quantity and variety of material be present at the work site, or that the assembly worker travel back and forth to storage sites to fetch the necessary parts, welding equipment, mounting hardware, and tools. The process is inherently inefficient and costly with regard to labor and warehousing. 
         [0008]    The completed trailer is stored in the manufacturer&#39;s inventory, shipped to dealers on flat bed trucks, and stored in dealers&#39; lots for sale. Each trailer encloses a large volume of empty space, as well as occupies a significant ground area that is defined by the footprint of the box, plus the distance that the tow bar and trailer hitch extend from the box. Ground space is expensive and this use of space on a dealer&#39;s lot to show and store cargo trailers is costly. 
         [0009]    What is needed, therefore, is a more economical method of constructing a cargo trailer. What is further needed is a cargo trailer assembly kit that allows significant economic savings in assembly, shipping, and storage. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The invention is a trailer kit comprising a bundled collection of easily assemblable pre-fabricated or pre-assembled components. All components are easily assembled with common assembly tools, such as screw drivers and wrenches. The trailer kit eliminates all or nearly all wasted space, both interior and exterior, that is occupied by the conventional assembled cargo trailer. Furthermore, the trailer kit is stackable, one on another, allowing multiple cargo trailer kits to be stored on the same footprint as a single kit and thereby increasing the number of cargo trailers that may be shipped at once on one flatbed or within a van or shipping container. This significantly reduces both storage and shipping volume, resulting in significant savings for manufacturers, shippers, and sellers. 
         [0011]    The cargo trailer kit according to the invention comprises pre-fabricated components that include a floor, wall panels, and a roof, and which, when assembled, form the cargo “box.” Additional pre-assembled or ready-to-assemble components include a tow bar, an axle or axles, wheels, finish trim pieces, and all hardware needed for final assembly. The floor is a complete pre-fabricated chassis unit that includes flooring installed on a chassis frame, along with insulation as needed and appropriate, and any fixtures intended for accommodating specific equipment or cargo, such as moving vehicle signal lights. Likewise, the wall panels and the roof are each complete pre-fabricated units, each unit including a frame with an exterior panel or skin affixed to it. Insulation, an interior panel or skin, as well as lighting and other fixtures, may be included in the panel, as applicable and as desired. A wiring harness for connecting moving vehicle signal lights and any lighting fixtures to the tow vehicle power supply is also included. One of the wall panels is a rear access panel that includes a door. This rear access panel is also a completely pre-fabricated unit that includes a hinged door and the requisite door hardware. Each panel is finished with sealer, paint, or other finishes, depending on the particular model and intended use of the cargo trailer. 
         [0012]    The pre-fabricated units are flat units that are stackable, one on top of the other. Placed on top of this stack of pre-fabricated units are additional components necessary to complete the cargo trailer, including hardware for assembly, such a nuts and bolts and other threaded fasteners, finish trim sheets, a tow bar, an axle assembly, and wheels pre-mounted with tires. The cargo trailer kit according to the invention contains all components to quickly and easily assemble a cargo trailer. General assembly tools, such as screw drivers and wrenches, are used to assemble the various units and components. The compact bundle allows multiple cargo trailers to be shipped and stored in a smaller footprint than the space required to ship or store a single assembled cargo trailer. 
         [0013]    The chassis has a panel-receiving channel that extends around the two sides and the front of the box. The channel is constructed to receive the lower ends of the wall panels that form the box. The roof also has a channel for receiving the upper ends of the wall panels. The rear-access panel is affixed to the rear side of the chassis and has a support flange for supporting in the vertical dimension the side edges of the two panels that abut the rear-access panel. The side wall panels are fitted into the channel in the chassis and pushed up against the rear-access panel. The front wall panels are placed in the channel in the chassis, at the front of the box. The roof is then placed over the top of the panels, the upper edge of each side panel, front-wall panel, and rear-access panel fitting into the channel in the roof frame. The side and front panels are then secured to the chassis and the roof by bolting them or otherwise securing them to the respective roof and chassis frames. Trim panels are secured to the exterior surfaces of the panels where they abut together, thereby covering any opening between the panels. Sealer may be applied to the seams along the trim panels to prevent the ingress of moisture into the panels. Wheels are mounted on an axle, which is assembled on the bottom of the chassis. Wheel fenders are assembled to the side of the chassis. A tow assembly is mounted on the chassis, for hitching the cargo trailer to the tow hitch on the towing vehicle. 
         [0014]    The frames for the chassis and the roof are formed from metal, preferably aluminum. Suitable sheet material is used for the exterior and interior panels, including the floor. For example, a thin metallic sheet may be used for the exterior panel, while a wood or wood fiber sheet material may be used for the interior panel and floor. Insulation may be incorporated into the frames, as desired. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. 
           [0016]      FIG. 1  shows a side plane view of the cargo trailer according to the invention. 
           [0017]      FIG. 2  shows a rear plane view of the cargo trailer according to the invention. 
           [0018]      FIG. 3  is an exploded view of the trailer kit according to the invention, bundled and ready for shipping, storage, or assembly. 
           [0019]      FIG. 4A  illustrates the frame of a side panel. 
           [0020]      FIG. 4B  illustrates a finished, pre-fabricated side panel. 
           [0021]      FIG. 5  is a cross-sectional view of the side panel of  FIG. 4B . 
           [0022]      FIG. 6A  illustrates the frame of a front-wall panel. 
           [0023]      FIG. 6B  shows finished, pre-fabricated front-wall panels. 
           [0024]      FIG. 7A  illustrates the chassis frame with tow assembly attached. 
           [0025]      FIG. 7B  is a side view of the chassis frame and tow assembly. 
           [0026]      FIG. 7C  is a cross-sectional view of the channel member, showing the first wall-panel receiving channel and flooring. 
           [0027]      FIG. 7D  is a perspective view of the rear right corner of the chassis and the access mounting strut. 
           [0028]      FIG. 8A  is a cross-sectional view of the rear-end of the chassis, with access-mounting strut. 
           [0029]      FIG. 8B  shows the finished, pre-fabricated chassis. 
           [0030]      FIG. 9A  illustrates the frame for the roof panel. 
           [0031]      FIG. 9B  shows a finished, pre-fabricated roof panel. 
           [0032]      FIG. 10  is a cross-sectional view of the roof panel, showing the second wall-panel receiving channel. 
           [0033]      FIG. 10A  is a cross-sectional view of the roof panel, showing an alternative embodiment of the exterior roof-frame member and the roof trim. 
           [0034]      FIG. 11  is a perspective view of the rear access panel with drop-down door. 
           [0035]      FIG. 12A  is a cross-sectional illustration of the side beam with side-panel support flange. 
           [0036]      FIG. 12B  is a top view of the rear right corner of a partially assembled cargo trailer, showing the rear-access panel attached to the rear end of the chassis, without the door mounted in the rear-access panel. 
           [0037]      FIG. 12C  is a side elevational view of the rear right corner of  FIG. 12B , showing the rear-access frame mounted on the chassis, with the side-panel support flange in place to support the rear end of the right side panel. 
           [0038]      FIG. 13  shows a rub rail that secures the rear end of the side panels to the rear-access panel. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    The present invention will now be described more fully in detail with reference to the accompanying drawings, in which an embodiment of the invention is shown. This invention should not, however, be construed as limited to the embodiment set forth herein; rather, they are provided so that this disclosure will be complete and will fully convey the scope of the invention to those skilled in the art. 
         [0040]      FIGS. 1 and 2  show a cargo trailer  200  according to the invention, completely assembled and ready for use. The cargo trailer  200  includes a container or box  120  mounted on a wheel assembly  140 , and a tow assembly  160  for towing it behind a powered vehicle. The box  120  provides a closed container that is made up of a chassis  110 , a rear access panel  136 , a roof panel  137 , and wall panels  130  that form the sides of the box  120 . Moving vehicle signal lights  150 , such as brake lights and directionals, are provided on the appropriate panels. In the embodiment shown, the box  120  has an aerodynamically angled front end  120 A and is otherwise rectangular in shape, as is best seen in the shape of the chassis in  FIG. 7A . The wall panels  130  include a left side panel  132 , a right side panel  133 , a left front panel  134 , a right front panel  135 . The particular shape of the cargo trailer  200  is not, however, limited to that shown in these figures, but may be any other useful shape. Another suitable shape for the box  120 , for example, is a straightforward rectangular shape, i.e., a box without the angled front end. 
         [0041]      FIG. 3  is an exploded view, showing a cargo trailer kit  100  according to the invention, which comprises pre-fabricated modular components that are readily assemblable to the cargo trailer  200 . This exploded view illustrates how the modular components may be bundled together, for shipping, storing, or assembly. The cargo trailer kit  100  shows the components for the box  120 , stacked one on top of the other, as well as the components for the wheel assembly  140  and the tow assembly  160 , which are shown placed on top of the box components. This figure is provided for illustration purposes only, to give an idea of how the cargo trailer kit  100  may be bundled for shipping, and may not be complete, that is, it may not show every component of the cargo trailer kit  100 . 
         [0042]      FIGS. 4A-6B  illustrate the construction of the wall panels  130 . The side panels  132  and  133  and the front-wall panels  134  and  135  are constructed similarly, but differ in size and shape. Each wall panel has a frame to which an exterior panel and an interior panel are attached.  FIG. 4A  shows a side panel frame  130 A for the side panels  132 ,  133  and  FIG. 6A  a front-wall panel frame  130 B for the front-wall panels  134 ,  135 . An interior panel  122  and an exterior panel  123  are securely affixed to the frames  130 A and  130 B. The exterior edges of the panels  130  that abut each other are sealed and trimmed with trim angle pieces  124 . Safety reflectors  125  are mounted on the panels  130  as shown in the figures. Also shown in  FIG. 5  is insulative material that may be incorporated into the wall panels  130 , if desired. An interconnecting wiring harness  116  is mounted to the interior panel  122 . In the embodiment shown, the wiring harness  116  is laid out along the top of one or both of the side panels  132  and  133  and down to the lower front corner, where it passes through an opening in the floor and extends to the front of the tow assembly  160 . Each end of the wiring harness  116  terminates in a conventional electrical connector  117 . The wiring harness  116  connects the moving vehicle signal lights  150  to the tow vehicle power supply, as well as any other light fixtures that may be provided on the various panels. 
         [0043]      FIGS. 7A ,  7 B,  7 C,  7 D, and  8 A and  8 B illustrate the chassis  101 , which comprises a chassis frame  110  having a first wall-panel receiving channel  111  along the upper edges of the frame  110 , formed by two flanges  111 A and  111 B. The rear of the chassis frame  110  ends in an access-panel-mounting strut  113  having a set of access-panel-mounting holes  114 .  FIG. 7A  shows the chassis frame  110 , constructed of transverse chassis frame members  110 A and long chassis frame members  110 B.  7 C shows a cross-section of the long chassis frame member  110 B, showing the first wall-panel receiving channel  111 . Transverse chassis members that form the outer ends of the chassis frame also have this first wall-panel receiving channel  111 , so that this channel extends around the perimeter of the chassis frame  110 .  FIG. 7C  is a cross-sectional illustration of the chassis  110 . A floor  115  is placed on the upper side of the chassis frame  110  within the area defined by the long chassis frame members  110 B and secured to the long frame members  110 B by some conventional fastener means  2 . Also indicated with dashed lines in  FIG. 7C , is a wall panel  130  fitted into the first wall-panel receiving channel  111 , also secured with a fastener  2 .  FIG. 7D  is a perspective view of the rear right corner of the channel member  110 B and the access-mounting strut  113 . In the embodiment shown, the long frame member  110 B and the mounting strut  113  are welded together, as indicated by the zigzag lines. It is understood that other methods of securely and rigidly attaching the mounting strut  113  to the channel member  110 B are within the scope of the invention.  FIG. 8A  is a partial cross-sectional view of the rear end of the chassis  101 , showing the mounting strut  113  in plane view and the flooring  115  and the first panel-receiving channel  111  in cross-sectional view.  FIG. 8B  shows the chassis  101  with flooring  115  filling out the area between the long frame members  110 B and the mounting strut  113 . A wiring harness  116  for connecting electrical lights or other devices to an electrical connector from the towing vehicle extends up through the floor  115  and ends with a connector  117 . The other end of the wiring harness  116  is left free for connecting to wiring from the towing vehicle. 
         [0044]      FIGS. 9A ,  9 B, and  10  illustrate the roof panel  137 .  FIG. 9A  shows a roof-panel frame  20 , constructed of exterior frame members  20 B and, optionally, interior frame members  20 A. The exterior frame members  20 B define the perimeter of the roof frame  20 .  FIG. 9B  shows the complete pre-fabricated roof panel.  FIG. 10  shows the cross-section of the roof panel  137 , showing the channel construction of the exterior roof-frame member  20 B. A second wall-panel receiving channel  21  is formed by an outer flange  21 A and an inner flange  21 B on the exterior roof-frame members  20 B, so that the second wall-panel receiving channel  21  extends around the entire perimeter of the frame  20 . In the embodiment shown in these Figures, two parallel exterior frame members  20 B further have a horizontal short flange  20 C that forms a channel  20 D for receiving an exterior roof panel or skin  22 . Also indicated in dashed lines is one wall panel  130 , which is fitted into the second wall-panel receiving channel  21  and secured by means of a fastener to the channel frame member  20 B. 
         [0045]      FIG. 10A  shows a cross-sectional view of an alternative embodiment of a roof panel assembly  237 , which includes a roof frame  220  plus roof skin  22  and roof trim  228 . The roof frame  220  is constructed of exterior roof-frame members  224  and optionally interior transverse roof-frame members  220 A. These exterior roof-frame members  224  are L-shaped, having a horizontal flange  226  that is dimensioned to receive and cover the upper edge of the wall panels  130 . This horizontal flange  226  extends around the entire perimeter of the roof-panel frame  220 . A second wall-panel receiving channel  221  is formed by the horizontal flange  226  and roof trim  228 . When the trailer box is being assembled, the lower edges of the wall panels  130  are placed in the first wall-panel receiving channel  111 . The roof panel  237  is then placed over the upper edges of the wall panels  130  so that the horizontal flange  226  extends over the upper edge of the wall panels. Roof trim  228  is assembled over the joint formed where the roof-panel assembly  237  and the wall panel  130  come together and fastened in place to the exterior roof-frame members  224 . 
         [0046]      FIGS. 11-12  C illustrate components for the rear of the cargo trailer  200 .  FIG. 11  is a perspective view of the rear access panel  136 , which comprises a rear-panel frame  30  having a lower beam  35 , two side beams  37 , and an upper beam  31 , which together define an access way  32  into the assembled box  120 .  FIGS. 12A-12C  illustrate details of the side beam  37 , which has a side-panel support flange  33 . A door  34  is mounted within the frame  30 . In the embodiment shown, the door  34  is a drop-down door that is secured to the side beams  37  by safety locks  38 . When assembled onto the cargo trailer  200 , the door hinges  35  are bolted to the rear-access strut  113  through the mounting holes  114 . It is understood that the door  34  may be any type of door suitable for the intended use of the cargo trailer  200 , such as a side-opening door or a door that slides upward. Tail lights  39  are mounted into each side beam  37 . A tail-light wiring harness is laid out along the interior side  41  of the rear-panel frame  30  in conventional manner. 
         [0047]      FIG. 13  illustrates a rub rail  138  that is affixed to the rear end of the cargo trailer  200 , to secure and seal the rear end of the side panels  132  and  133  to the door panel  137 . The rail rub  138  has a first flange  138 A that, when assembled, extends across a portion of the side beam  37  and a second flange  138 B that extends across a rear edge of the side panel  132 / 133 . As shown in  FIG. 1 , two rows of fasteners  138 C and  138 D are used to fasten the second flange  138 B to the respective side panel  132 / 133 . The first flange  138 A, shown in  FIG. 2 , is fastened to the side beam  37 . 
         [0048]    To assemble the cargo trailer  200  from the cargo trailer kit  100 , the axle assembly  142  is first attached to the underside of the chassis  110  and the tow bar  168  bolted to the underside of the chassis  110 , such that the tow bar  168  extends forward from the chassis  110 . The wiring harness  116  that connects moving vehicle signal lights  150  to a wiring harness from the towing vehicle is secured along the tow bar  168 . The chassis is then turned right side up and set on blocks. The lower beam  35  of the rear access wall panel  136  is bolted, welded, or otherwise rigidly affixed to the access-panel mounting strut  113 . The lower edge of each side panel  132 ,  133  is inserted into the first panel-receiving channel  111  of the chassis  110  and the rear end of the side panel abutted up against the side beams  37 , such that the panel support flange provides support for the side panel. The rub rail  138  is fastened to the side panels  132 ,  133  and the side beams  37 . The lower edge of each of the front panels  134  and  135  is then inserted into corresponding sections of the first wall-panel receiving channel  111 . Once all side panels  130  are mounted in the first wall-panel receiving channel  111 , the roof panel  137  is assembled on top of the side panels  130  and the rear-access panel  136 , such that the second wall-panel receiving channel  21  fits over the upper edges of all of the panels that form the sides of the box  120 : the rear access panel  136 , the side panels  132  and  133 , and the front panels  134  and  135 . Fasteners are fastened to the outer flange  21 A and the inner flange  21 B, to secure the panels  130  to the roof panel  137  and through the flanges  11 A and  111 B on the channel members  110 B to secure them to the chassis  101 . If the alternative embodiment of the roof panel  237  is used, the second wall-receiving channel  221  for receiving and securing the wall panels  130  is accomplished in a two-step process: the roof panel  237  is fitted over the upper edges of all the panels  130 , the roof trim  228  placed over the roof panel edge, so as to cover the upper edge of the wall panel  130 , and the roof trim  228  then fastened to the exterior roof-frame members  224 . A finishing strip  111  is affixed to adjacent side panels  130 , as shown in  FIG. 1 , to cover up a gap formed by abutting side panels. A wheel-mounted tire  144  is mounted to each end of the axle assembly  142 , and a fender  112  is mounted to the side walls  132  and  133  over each wheel-mounted tire  144  The wiring harnesses  116  are connected together with electrical connectors  117 . The cargo trailer  200  is now completely assembled and ready to be hitched to a towing vehicle. 
         [0049]    The frames for the wall panels, the roof panel, and the chassis are preferably made of aluminum. Tubular members are welded together to form the desired shape. Fasteners are used to secure the various panels to the frames. These fasteners may be self-threading screws that are drilled into the frames, or bolts that are inserted into pre-formed bolt holes. 
         [0050]    It is understood that the embodiment described herein are merely illustrative of the present invention. Variations in the construction of the cargo trailer kit and its assembly may be contemplated by one skilled in the art without limiting the intended scope of the invention herein disclosed and as defined by the following claims.