Patent Abstract:
A wall structure of a trailer box ( 10 ) is constructed from a plurality of panels ( 36, 38, 40 ) which are welded together where their edges meet. The panels ( 36, 38, 40 ) are each extrusions and each includes thin side skins ( 42, 44 ) and thin webs ( 46, 48, 50 ). The edge regions that are connected together include thickened portions that dissipate a substantial amount of the heat provided by the welds ( 56, 58 ). A plurality of panels ( 36, 38, 40 ) are welded together to form a large wall structure (WS). This wall structure (WS) is then reconfigured by a roll-forming machine (FIGS.  8-10 ) to provide a box ( 10 ) having a longitudinally straight and laterally curved configuration. Laterally considered, the box ( 10 ) has a concave inner side and a convex outer side. This shape of the box provides the box with both sidewalls and a bottom. The overall construction of the trailer box is lightweight and quite strong and facilitates construction of the truck/trailer box.

Full Description:
RELATED APPLICATION 
   This application is a divisional of U.S. Ser. No. 10/127,057, filed Apr. 19, 2002 now U.S. Pat. No. 6,688,673, and entitled Truck/Trailer Box Constructions. 
   This application is a continuation-in-part of my application Ser. No. 09/754,705, filed Jan. 4, 2001 now U.S. Pat. No. 6,425,626, and entitled TRUCK/TRAILER BOX CONSTRUCTIONS. 

   TECHNICAL FIELD 
   This invention relates generally to a truck/trailer box construction having a sidewall structure that is longitudinally straight and laterally curved, and having a concave inside shape and a convex outside shape. More particularly, it relates to the provision of such a sidewall structure that is formed from spaced apart inner and outer skins and longitudinally spaced apart webs that extend between and interconnect the two skins. It also relates to a method of making the sidewall structure and a truck/trailer box utilizing the sidewall structure. 
   BACKGROUND OF THE INVENTION 
   Known truck/trailer boxes that are longitudinally straight and laterally curved, and which have a concave upper side and a convex lower side, are shown by the following United States Patents: U.S. Pat. No. 1,805,489, granted May 19, 1931, to Arthur G. Kerr and Daniel Merchant; U.S. Pat. No. 3,844,616, granted Oct. 29, 1974, to Douglas B. Acre; U.S. Pat. No. 4,948,155, granted Aug. 14, 1990, to Fred T. Smith and Fred P. Smith; U.S. Pat. No. 5,090,773, granted Feb. 25, 1992, to Bernard Guillsume; and U.S. Pat. No. 5,482,359, granted Jan. 9, 1996, to Albert A. Goodson. These patents should be carefully considered for the purpose of putting the present invention into proper prospective relative to the prior art. 
   There is a need for a way of constructing the sidewalls of the truck/trailer boxes from materials that are very lightweight but yet are strong and rigid. There is also a need for such a truck/trailer box construction that permits the sidewall to be built in sections that can be welded together while allowing for the use of very thin skins and webs that are themselves too thin to be welded. A principal object of the present invention is to fulfill these needs. 
   BRIEF SUMMARY OF THE INVENTION 
   A truck/trailer box construction of the present invention comprises a longitudinally straight sidewall structure having a laterally concave inside shape and a laterally convex outside shape. The sidewall structure comprises spaced apart inner and outer skins and longitudinally spaced apart webs, extending between and interconnecting the two skins. In preferred form, the sidewall structure is formed from a series of panels that are welded together at edges where they meet. Preferably, the upper and lower skins and the webs are constructed from an aluminum alloy material, or the like, and are formed by extrusion. 
   The method of the present invention is basically characterized by providing a sidewall panel structure that includes an upper skin, a lower skin and a plurality of parallel, longitudinally spaced apart, webs, which extend between and interconnect the skins. This sidewall panel structure is roll formed to give it a longitudinally straight and transversely curved shape. To do this, a plurality of forming rolls are provided in a cluster. Adjacent rolls form nips for receiving the panel structure. The panel structure is fed into the nips, with their webs disposed substantially perpendicular to the axis of the rolls. The sidewall panel structure is fed through the rolls several times in order to bend the wall structure a small amount each run through. 
   The present invention provides a truck/trailer box construction in which the floor and the sides of the box are created without a seam or a weld joint connecting them together. A plurality of long extrusions are used to create the floor and the sides of the box. The extrusions are welded together at their edges to form a single large panel structure that is then transformed by roll forming into a substantially semi cylindrical shape. The resulting box structure preferably has substantially flat upper side portions that extend the full length of the box above the portion of the panel structure that is roll formed. Herein the structure that is formed by welding a plurality of elongated panels together is referred to as sidewall structure even though it also forms a bottom for the box when it is reconfigured by roll forming. 
   The present invention also permits the elimination of longitudinal supports or stiffeners for the panels that are normally a part of the prior art boxes, which have rounded bottom. The longitudinal supports and/or stiffeners are not needed because the sidewall structure is stiffened by the skins and the webs that extend between and interconnect the skins. The webs are in effect ribs inside the sidewall structure and they are sufficient to provide the strength and stiffening that the sidewall structure needs. 
   The present invention includes constructing a truck/trailer box from panels of aluminum extrusions and welding the panels together in a way that minimizes loss of strength caused by heat from the welds. In the panel and joint construction of the invention, a substantial part of the heat dissipates in two webs that meet at the joint and in thickened corner regions formed where the webs meet the skins of the panels. The dissipation of the heat from the weld in these regions minimize heat dissipation in the skins of the panel away from the joints where strength is needed. 
   Other objects, advantages and features of the invention will become apparent from the description of the best mode that is set forth below, from the drawings, from the claims and from the principals that are embodied in the specific structures that are illustrated and described. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     Like reference numerals are used to designate like parts throughout the several views of the drawing, and: 
       FIG. 1  is a fragmentary side elevational view of one embodiment of the invention, such view showing foreground portions of the truck/trailer box, and a housing within the box, both cut away for the purpose of showing a portion of a cylinder that is provided for raising and lowering the box relative to the truck/trailer frame: 
       FIG. 2  is a pictorial view of the truck/trailer box shown by  FIG. 1 , such view looking towards the front and one side of the box; 
       FIG. 3  is an exploded pictorial view of the truck/trailer box shown by  FIGS. 1 and 2 ; 
       FIG. 4  is a fragmentary sectional view taken substantially along line  4 — 4   FIG. 1 ; 
       FIG. 5  is a side elevation view of a second embodiment of the invention; 
       FIG. 6  is a fragmentary pictorial view showing the lifting cylinder being used to tilt the truck/trailer box upwardly from a truck/trailer frame; 
       FIG. 7  is a transverse sectional view taken substantially along line  7 — 7  of  FIG. 5 , but with the truck/trailer frame omitted; 
       FIG. 7A  is an enlarged scale sectional view taken substantially along line  7 A— 7 A of  FIG. 4 ; 
       FIG. 8  is an end view showing a thin skinned, hollow core panel, positioned to enter into the forming rolls of a roll forming machine; 
       FIG. 9  is a view like  FIG. 8 , but showing the panel in the process of being bent by the forming rolls: 
       FIG. 10  is a view like  FIGS. 8 and 10 , but showing a final stage of roll forming the panel to form the sidewall of the truck/trailer box; 
       FIG. 11  is an enlarged scale end elevational view showing confronting edges of adjacent extrusions spaced from each other; and 
       FIG. 12  is a view like  FIG. 11 , but showing the two edges of the extrusions together and further showing welds connecting the extrusions together where they meet. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a truck/trailer box  10  mounted on a truck/trailer chassis  12 . Box  10  includes a sidewall structure  14 , a base frame  16 , a front wall  18 , and a rear door  20 . The base frame  16  is hinge connected at  22  to the chassis frame  12 . A hydraulic cylinder  24  is pin connected at its lower end to the chassis frame  12  and at its upper end to the box  10 . It serves to raise and lower the box  10  relative to the chassis frame  12 . Cylinder  24  is shown in a retracted position in FIG.  1 . It includes a piston component  26  and a cylinder component  28 . The base in the cylinder component  28  is connected to the frame structure  12  by a pivot pin  30 . The upper end of the piston rod component is connected to a housing  32  by a pivot pin  34 . The inner housing  32  is provided to receive the cylinder  24 . In  FIG. 3 , housing  32  is shown outside of the sidewall structure  14 . 
     FIG. 1  shows the cylinder  24  retracted and the box  10  resting on the chassis frame  12 . When cylinder  24  is extended, the piston rod component  26  moves upwardly out of the cylinder component  38  and pushes up on the upper forward end portion of the box  10 . This causes the box  10  to swing upwardly about pivot pin  22  into a rearward tilting position. 
   Referring to  FIG. 3 , the first embodiment has a sidewall structure  14  that is constructed from three panels  36 ,  38 ,  40 . Each panel  36 ,  38 ,  40  includes an inner skin  42 , an outer skin  44  and a plurality of webs  46 ,  48 ,  50 . A typical panel has one web  48 , one web  50  and twelve webs  46 . Panels  36 ,  38 ,  40  are formed by extrusion. The webs  46 ,  48 ,  50  extend longitudinally of the panels  36 ,  38 ,  40  when the panels  36 ,  38 ,  40  are still flat and straight. Preferably, the flat panels  36 ,  38 ,  40  are brought together at their edges. The web  48  on panel  36  is mated with the web  50  on panel  38 . In similar fashion, the web  48  on panel  38  is mated with the web  50  on panel  40 . The webs  50  include longitudinal tongues  52  that fit inside of longitudinal grooves  54  formed in the webs  48 . The outside corner regions of webs  48 ,  50  are beveled [FIG.  4 ] and when a web  48  is mated with a web  50 , a v-groove is provided by the bevels on both the inside  42  and the outside  44  of the two panels being joined. Following mating of each web  48  with a web  50 , the v-groove are welded, so as to form filet welds  56  on the inside of the panels and filet welds  58  on the outside of the panels. The welds  56 ,  58  and the cross sectional configuration of the webs  48 ,  50  provide a sectional shape at the joints that bares similarity to an  120  beam. Each such I-beam region is an integral part of the joint and hence is an integral part of the sidewall structure. The panel and joint construction used in the wall structure of the present invention is essentially like the panel and wall construction disclosed in the aforementioned co-pending application Ser. No. 09/754,705. The contents of that application are hereby incorporated in the application by this specific reference, under the doctrine of incorporation by reference. 
   When the panels  36 ,  38 ,  40  are joined and welded together, they form a sidewall structure that is flat. This structure is as long as the combined widths of the panels  36 ,  38 ,  40  and is as wide as the common length of the panels  36 ,  38 ,  40 . After the panels  36 ,  38 ,  40  are welded together, to form a unitary structure composed of a skin on  35  each side and a plurality of webs interconnecting the skins, the wall structure is roll formed into a shape that is close to being semi cylindrical. By way of typical and therefore non-limitive example, the roll forming can be done by use of a standard plate roller, for example, such as are made by The Webb Corporation having a business address of 402 East Broadway, Webb City, Mo. 64870.  FIGS. 8-10  are end views of a Webb three roll bending machine. This equipment comprises rolls  1 ,  2 ,  3 .  FIG. 8  shows the wall structure WS being moved towards a nip that is formed by and between rolls  1  and  2 . A second nip is formed by and between rolls  1  and  3 . The wall structure WS is oriented with the webs  46 ,  48 ,  50  perpendicular to the axes of rotation of the rolls  1 ,  2 ,  3 . Thus, the bending that is done bends both the skins  42 ,  44  and the webs  46 ,  48 ,  50 . Referring to  FIG. 9 , the rolls  1  and  2  move the wall structure WS into contact with the roll  3 . Bending does not commence immediately and so the leading portion of the wall structure WS, designated  60 , remains flat. The amount of curvature caused by each run through of the wall structure WS can be changed by vertical movement of the roll  3 . Roll  3  is positioned so that the wall structure WS is bent only a small amount each time it is passed through the forming equipment. The first pass through the rolls  1 ,  2 ,  3  puts a small amount of curvature in the wall structure WS. Prior to each additional pass through the equipment, the roll  3  is moved higher so that it will put an additional small amount of bend into the wall structure WS. Thus, the wall structure WS is moved through the rollers  1 ,  2 ,  3  several times until the desired radius of curvature is achieved. Each time, care is used to not bend the leading and trailing portions  60 ,  62 . This provides a flat portion in the upper sidewall regions of the box  10 . If an attempt had been made to bend the wall structure WS the full amount in one pass, the webs  46 ,  48 ,  50  would most likely collapse. However, it was found that the webs  46 ,  48 ,  50  can be bent along with the skins  42 ,  44  if multiple passes are used and a small amount of bending is done per each pass. 
     FIG. 3  shows the panels  56 ,  38 ,  40  spaced apart while they are in a bent condition. This has been done for the purpose of making it easier to see the construction of the box  10 . However, as described above, the panels  36 ,  38 ,  40  are welded together while in a flat condition. Then, the combined structures  36 ,  38 ,  40  (wall structure WS above) is roll formed into the desired shape. This shape is substantially semi cylindrical but with upper side portions  60 ,  62  that are substantially flat. 
   The panel sections  36 ,  38 ,  40  are connected together by weld beads  56 ,  58 , one on each side of the structure. By way of example, the thickness dimension T for the panel sections  36 ,  38 ,  40 , may be substantially about 1½ inches. The skins  42 ,  44  and webs  46 ,  48 ,  50  may be substantially about 0.09 inches thick. The center-to-center dimension between adjacent webs  46 ,  48 ,  50  may be substantially about 1.763 inches. An important dimension is the thickness Z in the region of the welds  56 ,  58 . In the example, this thickness is substantially about 0.188 inches. The weld recess width W is substantially about 0.250 inches. The weld recess depth D is substantially about 0.125 inches. 
   In preferred construction, the edge walls or webs  48  are formed to include a longitudinally extending groove  54 . The edge walls or webs  50  are provided with a complementary longitudinally extending tongue  52 . As shown by  FIG. 12 , the tongue  52  makes a loose fit with the groove  54 . In the given example, the tongue width may be substantially about 0.1875 inches. The groove width may be substantially about 0.25 inches. The tongue length may be about 0.1825 inches. The groove depth may be substantially about 0.2475 inches. During assembly, two panel sections to be joined are brought together. The tongue  52  on one is inserted into the groove  54  in the other. Then, the side planes of the two panel sections are put into substantial coplanar alignment and the weld beads  56 ,  58  are placed within the weld recesses. The tongue and groove components facilitate the welding process. If they were not present when the panels were welded together, the panels would expand and contract and become “wavy” down the length of the side. This would make it impossible to weld properly. It would be possible to “tack” weld every twelve inches on one side, but this would be impractical. The invention includes any type of tongue and groove system that holds the panels parallel to each other for welding purposes. For example, a two tongue and two groove system could be used. 
   At each joint, the diagonal corner regions  64 ,  66  provide both structural reinforcement and width and depth for the weld beads  56 ,  58 . A weld bead  56 ,  58  that is substantially triangular in cross section, substantially about 0.250 inches wide, and substantially about 0.125 inches deep is made possible because of the thickness of the material in regions  64 ,  66 . The corner regions  64 ,  66  and the weld beads  56 ,  50  together form outwardly widening flanges that, together with the wall sections  48 ,  50  provide a reinforcing beam section at the location of each joint. This beam section extends the full length of the joint and its parts  48 ,  50 ,  64 ,  66  in effect form I-beam like longitudinal stiffening and strengthening ribs at each joint location. 
   The panels  36 ,  38 ,  40  that make up a sidewall are preferably laid flat on a jig. They are then clamped and tack welded about every four feet on the underneath side. They are no tack welds on the top. Then, all panels are welded the full length of the wall, simultaneously. The wall forming panel assembly is then flipped over to position its welded side facing downwardly. The wall structure is then clamped down and the new “up” side is welded the full length, simultaneously. As can be seen, there is no weld seams created that extend from one side of the wall structure to the other. There is no need for longitudinal structural members for strengthening the wall structure. The wall structure itself makes this unnecessary. 
   The front wall  18  is preferably also made from panels that are composed of skins  42 ,  44  that are held spaced apart and are connected together by webs  46 ,  48 ,  50 . Referring to  FIG. 2 , the front wall  18  is shown, for example, to be formed from panels  70 ,  72 ,  74 ,  76 . Joints  78 ,  80 ,  82  are formed where the panels  70 ,  72 ,  74 ,  76  meet. These joints  78 ,  80 ,  82 , are preferably like the joints shown in  FIG. 4 , and are composed of edge webs, tongue-and-groove members, V-grooves for the welds, and weld beads in the V-grooves. 
   The cylinder housing  32  is formed of sheet metal panels that are welded together. Then, the housing  32  is placed within the box  10  and is welded at its bottom edges to the panel  36  and at its rear edges to the wall  18 . An access window  84  is provided in the wall  18 , to provide access into the cylinder housing  32 . 
   A bottom opening  86  is provided in one or both of the panels  36 ,  38  to accommodate the lower portion of the cylinder  24  as it extends through the bottom of the box  10  to an anchor location on the frame  12  below the box  10 . The upper edge or front wall  18  is preferably provided with a cap  88 . In similar fashion, on the opposite sides of the box  10 , caps  90  are connected to the upper edges of the sidewall portions  60 ,  62 . The caps  10  keep dirt and water out of the extrusions. They are not provided for strengthening the body. The strength of the rolled extrusions eliminates the need for a top rail that provides extra strength. An end cap  92  is preferably connected to the rear edge of the panel  40 , to reinforce the rear edge and provide a stop for the door  20 . Members  86 ,  92  may be made from tubular stock while the members  90  are made from channel stock. The upper edge portions are received within a channel space in the members  90 . 
   In  FIG. 3 , the upper rear corner regions of the panel  40  are shown to be notched at  94 ,  96 . Pin plates  98 ,  100  are received within the notches  94 ,  96  and are welded to the panel  40 . Pin plates  98 ,  100  are a part of a pair of knuckle hinges which further include apertured plate pairs  104 ,  106  at the upper corners of the door  20 . Plates  98 ,  100  extend between the two plates of each pair  102 ,  104  and pivot pins are inserted through the three plates at each ends location to complete the hinge structure. 
   Door  20  is preferably also constructed from panels  106 ,  100 ,  110  that are welded together where they meet. 
     FIGS. 5 and 6  relate to a larger box  112  mounted on a trailer chassis  114 . The box  112  is composed of sections  116 - 138 , constructed and connected together in the manner described above in connection with the first embodiment. These side portions of the box  112  include substantially flat upper portions and a cap structure  140 . The front end of the box  112  includes an end wall  142 . A door  144  is provided at the rear of the box  112 . The three adjacent sections  116 ,  118 ,  120  at the rear of the box  112  are connected at their bottoms to a frame  146 . This frame  146  is reinforced by gussets  148 ,  150 ,  152 ,  154  and it is hinge connected at  156  to the frame  114 . As shown by  FIG. 6 , a tipping cylinder  158  is provided at the front end of the box  112  and the front end of the frame  114 . A pair of bottom rails  160 ,  162  are provided at laterally spaced apart locations on the bottom of the box  112 . These rails  160 ,  162  make contact with the chassis frame  114  when the box  112  is supported by the chassis frame  114 . The rails may comprise generally C shaped extrusions which receive elastimeric bumper strips. The elastimeric strips are receive in the extrusions. It is the elastimeric strips that make contact and prevent the aluminum from rubbing on the frame. The elastimeric strips also function as shock absorbers between the frame and the aluminum. The extrusions and the elastimeric strips do not function to reenforce the aluminum body structure. As previously stated, longitudinal supports and/or stiffeners are not needed because the side wall structure is stiffened by the skins and the webs that extend between and interconnect the skins. 
     FIG. 7  is a sectional view taken through the section  136  of the box  112 , substantially along line  7 — 7  of FIG.  5 . It shows the thickness of the skins  160 ,  162  on an exaggerated scale relative to the web width  164 .  FIG. 7A  is an enlarged scale of a portion of  FIG. 7  that presents the parts  160 ,  162 ,  164  in a more realistic scale. Typical dimensions of the parts are stated above in the description of the first embodiment.  FIG. 7  shows upper side regions  166 ,  168  of the box  112  which are substantially flat. That is, the box structure  112  is substantially straight both vertically and horizontally in regions  166 ,  168 . Below regions  166 ,  168 , the wall structure forming the box  112  has been roll formed to give it a concave inner side  170  and a convex outer side  172 . Herein, the reference to the box structure being longitudinally straight and laterally curved applies even though the curvature stops below the upper sections  166 ,  168 . The wall structure is predominantly curved in the lateral direction because it has a concave inner side and a convex outer side even though the substantially flat sections  166 ,  168  are present. 
   The illustrated embodiments are only examples of the present invention and, therefore, are non-limitive. It is to be understood that many changes in the particular structure, materials and features of the invention may be made without departing from the spirit and scope of the invention. Therefore, it is my intention that my patent rights not be limited by the particular embodiments illustrated and described herein, but rather are to be determined by the following claims, interpreted according to accepted doctrines of patent claim interpretation, including use of the doctrine of equivalents and reversal of parts.

Technology Classification (CPC): 1