Abstract:
The wall joint of the present invention is configured to reduce or eliminate protrusions into the interior of the trailer or container, but does not require coining or stamping of the edges of consecutive sidewall panels. According to some highly preferred embodiments of the present invention, the wall joint includes two consecutive sidewall panels, each bent to form a main plateau, a spliced plateau and a jogged portion serving as a transition therebetween. In this way, the spliced plateau lies in a plane substantially parallel to, but spaced apart from, the main plateau, with the thickness of the sidewall panel most preferably remaining substantially constant throughout. When two consecutive sidewall panels are positioned next to each other, the spliced plateaus of the two consecutive sidewall panels abut each other and lie in a first plane, while the main plateaus of the two panels preferably lie in another parallel plane. Thus, a region recessed from the main plateaus and surrounding the seam between the two panels is created. The main plateaus preferably comprise the bulk of the interior, generally smooth-walled, surface of the cargo body, interrupted only by periodic recessed regions created by the spliced plateaus at the seams between the sidewall panels. While it is preferable for the main plateaus to lie in a single plane to create a generally flat interior cargo body wall, it is not necessary. In some highly preferred embodiments, adhesive and rivets are employed to further strengthen the sidewall panel joints.

Description:
RELATED APPLICATIONS 
     This is a continuation-in-part of U.S. patent application Ser. No. 09/633,652, filed on Aug. 7, 2000 and issued on Sep. 17, 2002 as U.S. Pat. No. 6,450,564, the entire disclosure of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to devices and configurations for joining panels, and more particularly to devices and configurations for joining consecutive sidewall panels of a trailer or container. 
     BACKGROUND OF THE INVENTION 
     Freight is typically carried on highways in either trailers or containers. The primary distinction between the two is that trailers have wheels and are pulled behind tractors, while containers are simply “boxes,” similar in appearance to the “box portions” of trailers, which are carried on chassis pulled behind tractors. In either case, the sidewalls are usually constructed by coupling, side-by-side, a plurality of vertical sidewall panels. As used herein and in the appended claims, the term “cargo body” refers to the sidewalls of a trailer, cargo container, truck body, or other cargo carrying body. Also, the term “sidewall” is not limited to the longitudinal walls of a trailer or cargo container, and include any walls (front walls, rear wall, walls connecting the front and rear walls, etc.) of a trailer or cargo container. 
     The most conventional sidewall construction is commonly referred to as “sheet and post” construction. In this type of construction, adjacent vertical edges of two consecutive, relatively thin, panels are overlapped and riveted together to form a joint. Additionally, a vertical reinforcing rib is riveted at the seam between the two panels. In this type of construction, because the panels are made of a relatively thin “skin” material, the vertical reinforcing ribs, or “posts,” are needed for stiffness and strength. 
     A second, less common, but still conventional sidewall construction is referred to as “plate wall” construction. In plate wall construction, the panels are made of a thicker material than is used in sheet and post construction. The thicker panels provide enough stiffness and strength, themselves, that stiffening ribs or “posts” are not needed. The panels in plate wall construction are coupled in several different ways. Most commonly, two consecutive panels are butted up against each other and a plate or “splicer” is riveted to the consecutive panels to act as a bridge coupling them together. 
     Alternatively, the edges of consecutive panels may be overlapped and then riveted in a fashion similar to the way the panels are overlapped in sheet and post construction. In either case, the vertical edge of one or both consecutive sidewall panels is sometimes “coined” or stamped before being riveted to the adjacent panel. In some prior joint configurations, the coined edge of one sidewall panel overlaps the stamped or unstamped vertical edge of an adjacent sidewall panel and rivets are placed through the resulting, overlapping portion of the panels to secure them together. In other joint configurations, the edges of abutting, but not overlapping, consecutive panels are coined. Then, the coined portions of the consecutive panels are riveted to a splicer plate, which bridges between, and thereby connects, the panels. 
     In many prior joint configurations, coining is utilized to decrease protrusions into the interior of the trailer or container. Protrusions into the interior of the trailer or container may cause cargo to “catch” or “hang up” as it is being loaded and unloaded. Therefore, it is desirable for a trailer or container to have a smooth interior wall, free of protrusions. Rivets protruding into the interior of the trailer, splicer plates on the interior of the trailer over the seam between two panels, and uneven interior surfaces created by overlapping panels all create hindrances to the loading and unloading of cargo from the interior of the trailer. Additionally, these hindrances take up valuable space within the trailer which could otherwise be used for additional cargo. 
     These hindrances may be reduced or eliminated by coining the edges of the sidewall panels. Coining the edges of sidewall panels thins out the panels, creating recesses at the joints between panels, which, to varying degrees, couch protruding rivets, splicer plates, and overlapping panels. In this way, the interior surface of a trailer may be “evened out” or “smoothed out,” lessening or eliminating protrusions into the interior of the trailer. 
     Therefore, many prior joint configurations call for coining at least one vertical edge of the sidewall panels. However, coining the edges of the sidewall panels raises certain issues. Sidewall panels are typically of a composite construction or are constructed of aluminum. Composite sidewall panels include a plastic core material sandwiched between an inner and outer thin, metal skin, while aluminum panels are usually solid aluminum. In the case of composite panels, coining the edges necessarily either reduces the amount of core material at the edges, or severely compresses it. Many prior art joint configurations severely compromise the structure of composite sidewalls by coining their edges. In the case of aluminum sidewall panels, coining the panel edges creates additional problems. The solid nature of aluminum panels makes them difficult to coin and, once coined, the stress on the aluminum can compromise its integrity. Some prior configurations have attempted to reduce the existence of protrusions into the trailer interior without coining the panels. However, these configurations suffer from other pitfalls, including being overly complex, being costly, and, again, compromising the integrity of the panels. 
     In light of the limitations of the prior art described above, a need exists for an alternative, strong, adequately sealed, easily assembled joint configuration (and method of manufacturing such a joint) which reduces or eliminates the existence of hindering protrusions into the interior of the trailer or container, but which does not require the coining or stamping of the edges of the trailer sidewall panels. 
     SUMMARY OF THE INVENTION 
     The unique wall joint of the present invention is configured to reduce or eliminate protrusions into the interior of the trailer or container, but does not require the coining or stamping of the edges of consecutive sidewall panels. According to some highly preferred embodiments of the present invention, the wall joint includes two consecutive sidewall panels, each bent to form a main plateau, a spliced plateau and a jogged portion between the main plateau and the spliced plateau. The jogged portion of the sidewall panel serves as a transition between the main plateau and the spliced plateau. In this way, the spliced plateau lies in a plane substantially parallel to, but spaced apart from, the main plateau. However, the thickness of the sidewall panel most preferably remains substantially constant throughout. When two consecutive sidewall panels are positioned next to each other, the spliced plateaus of the two consecutive sidewall panels abut each other (in some embodiments) and lie in a first plane, while the main plateaus of the two panels preferably lie in a second, parallel plane spaced apart from the first plane. Thus, a region recessed from the main plateaus and surrounding the seam between the two panels is created. The main plateaus preferably comprise the bulk of the interior, generally smooth-walled, surface of the cargo body, interrupted only by periodic recessed regions created by the spliced plateaus at the seams between the sidewall panels. It should be noted that while it is preferable for the main plateaus to lie in a single plane to create a generally flat interior cargo body wall, it is not necessary. The main plateaus may lie at slightly different levels, with the spliced plateaus still forming a recessed region there between. 
     In some embodiments, the adjacent panels to be spliced abut one another along their adjacent edges. In other embodiment, the adjacent panels are spaced a distance apart from one another. 
     In accordance with some highly preferred embodiments, sidewall panels are positioned next to each other, and splicer plates preferably having adhesive on one side are then placed on either side of the abutting spliced plateaus to sandwich the recessed region between the splicer plates. In this way, the adhesive strips between the splicer plates and the sidewall panels serve to glue the splicer plates to the spliced plateaus of the sidewall panels creating a multiple layer joint connecting the two consecutive sidewall panels. The joint can then be further strengthened by placing a plurality of conventional fasteners, such as rivets (preferably at least one row on each side of the seam between the consecutive sidewall panels), through the entire multiple-layer joint. This unique joint configuration provides a simple, strong joint connecting consecutive sidewall panels. Moreover, this joint configuration serves to recess the splicer plates, adhesive layers, and rivets into the cargo body sidewall, thereby reducing or eliminating protrusions into the interior of the trailer or container. 
     It is often desirable to secure or stabilize cargo within a trailer or container. To provide this capability, the sidewall panels and/or the splicer plates have logistics apertures that enable a user to connect ropes, cord, cable, straps, bungee cords, or other elements to the trailer or container sidewalls. Such elements can be connected by being passed into and out of logistics apertures or by attachment to fasteners or fixtures that can mate with the logistics apertures or otherwise attach to the sidewalls via the logistics apertures. 
     Further objects and advantages of the present invention together with the organization and manner of operation thereof, will become apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings wherein like elements have like numerals throughout the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is further described with reference to the accompanying drawings, which show preferred embodiments of the present invention. However, it should be noted that the invention as disclosed in the accompanying drawings is illustrated by way of example only. The various elements and combinations of elements described below and illustrated in the drawings can be arranged and organized differently to result in embodiments which are still within the spirit and scope of the present invention. 
     In the drawings, wherein like reference numerals indicate like parts: 
     FIG. 1 is a perspective view of a trailer having wall joints, in accordance with the present invention, interconnecting a plurality of sidewall panels to create a sidewall; 
     FIG. 2 is a an exploded perspective view of a joint of FIG. 1 showing portions of two consecutive sidewall panels sandwiched between two sheets of adhesive and two splicer plates; 
     FIG. 3 is a perspective view of the joint of FIG. 2 showing the various elements of FIG. 2 riveted together; 
     FIG. 4 is an exploded perspective view of a joint according to another preferred embodiment of the present invention, showing portions of two consecutive sidewall panels sandwiched between two sheets of adhesive and two splicer plates; and 
     FIG. 5 is a perspective view of the joint of FIG. 4 showing the various elements of FIG. 4 riveted together. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIG. 1, sidewall joints of the present invention, indicated generally at  14 , serve to couple consecutive sidewall panels  15 ,  16  to form a sidewall  12  of a trailer  10 , container, truck body, or other cargo carrying body. Although the preferred embodiments of the present invention described below and illustrated in the figures are presented with reference to a trailer  10 , it should be noted that the present invention can be employed in a cargo container or any other box-type structure used to carry freight, whether permanently or removably secured with respect to a vehicle and whether having dedicated wheels or not. Sidewall panels  15 ,  16  preferably are formed of solid aluminum or constructed of a composite material having a plastic or epoxy core sheathed in a metal skin, but may be constructed of any of a number of other materials suitable for trailer sidewall panels, such as laminate panels, hollow-core panels, panels having a core filled with any desired material, panels made from steel or other metal, plastic, fiberglass, and the like. 
     Referring now to FIGS. 2 and 3, joint  14  is illustrative of a joint according to one highly preferred embodiment of the present invention as it would appear from the interior of a trailer. The interior space of the trailer would generally be in the foreground of FIGS. 2 and 3 and the space outside the trailer would generally be in the background of FIGS. 2 and 3. The illustrated embodiment of joint  14 , then, is generally comprised of a fore sidewall panel  15 , an aft sidewall panel  16 , an interior adhesive sheet  25 , an exterior adhesive sheet  26 , an interior splicer plate  23 , and an exterior splicer plate  24 . As further described below, interior and exterior adhesive sheets  25 ,  26  are preferably applied to interior and exterior splicer plates  23 ,  24  and then sandwiched around abutting fore and aft sidewall panels  15 ,  16 , thereby coupling them together. Rivets  34  (shown in FIG. 3) are then inserted through the layered elements for additional strength. 
     Referring specifically to FIG. 2, fore sidewall panel  15  includes a main plateau  17 , a spliced plateau  19 , and a jogged portion  21  serving as a transition between main plateau  17  and spliced plateau  19 . Similarly, aft sidewall panel  16  includes a main plateau  18 , a spliced plateau  20 , and a jogged portion  22  serving as a transition between main plateau  18  and spliced plateau  20 . Both fore and aft sidewall panels  15 ,  16  are configured such that main plateaus  17 ,  18  lie in planes separate from, and parallel to, their corresponding spliced plateaus  19 ,  20 . Jogged portions  21 ,  22 , then, serve as the transitions between main plateaus  17 ,  18  at one level and spliced plateaus  19 ,  20  at another level. As seen in FIGS. 2 and 3, it is apparent that jogged portions  21 ,  22  “move” or offset fore and aft sidewall panels  15 ,  16  from one plane at main plateaus  17 ,  18  to another plane at spliced plateaus  19 ,  20  without varying the thickness of panels  15 ,  16 . Put another way, the thickness of panels  15 ,  16  remains consistent throughout. 
     It will be readily understood by one of ordinary skill in the art that FIGS. 2 and 3 illustrate only small portions of sidewall panels  15 ,  16 . In reality, main plateaus  17 ,  18  extend well beyond the boundary of either FIG. 2 or FIG.  3  and preferably make up the majority of panels  15 ,  16 , and, therefore, of an interior wall surface  38  of the trailer. FIGS. 2 and 3 merely illustrate those portions of sidewall panels  15 ,  16  necessary to illustrate the detail of joint  14 . As can be seen in FIG. 1, in reality, the various sidewall panels preferably extend laterally a distance several times the width of joint  14 . 
     Consecutive fore and aft sidewall panels  15 ,  16  are situated beside each other at a seam  32  with spliced plateaus  19 ,  20  lying in one plane and main plateaus  17 ,  18  lying in another. Sidewall panels  15 ,  16  may be butted tightly against each other, or may be separated. Preferably, a small gap is left between panels  15 ,  16  so that panels  15 ,  16  are basically butted against each other, but do not need to be manufactured with a particularly high degree of precision. In any event, spliced plateaus  19 ,  20  cooperate to form a corrugated or recessed region  35  at the intersection of consecutive fore and aft sidewall panels  15 ,  16 . Recessed region  35  provides a degree of stiffness to joint  14  and a brief indentation, interrupting the otherwise smooth interior trailer wall surface  38  created by main plateaus  17 ,  18 . Recessed region  35  serves to couch interior splicer plate  23 , interior adhesive sheet  25 , and rivet heads  42  (shown in FIG. 3) as they cooperate with exterior splicer plate  24  and exterior adhesive sheet  26  to couple sidewall panels  15 ,  16  together, as further discussed below. 
     In accordance with one highly preferred embodiment, with sidewall panels  15 ,  16  butted against each other at seam  32 , adhesive sheets  25 ,  26  are preferably applied to interior surfaces  45 ,  46  of splicer plates  23 ,  24 . Then, interior and exterior splicer plates  23 ,  24 , with interior and exterior adhesive sheets  25 ,  26  thus applied, are adhered over seam  32  to sidewall panels  15 ,  16 . However, it will be readily understood by one of ordinary skill in the art that adhesive sheets  25 ,  26  (or any other suitable adhesive such as glue which is applied by spreading, double-sided tape, compounds, and the like) can be first applied over seam  32  to sidewall panels  15 ,  16  and, then, splicer plates  23 ,  24  adhered thereto. In either way, splicer plates  23 ,  24 , in combination with adhesive sheets  25 ,  26 , serve to couple fore sidewall panel  15  to adjoining aft sidewall panel  16 . Splicer plates  23 ,  24  are preferably galvanized steel, but any rigid plate material, including various metals, plastics, woods, composites, and the like, is suitable. Adhesive sheets  25 ,  26  are preferably a very high bond tape, but can include any number of suitable adhesives or cohesives, including glues, double-sided tapes, compounds, and the like. Additionally, it will be readily apparent to one of ordinary skill in the art that, if desired, joint  14  may be configured without any adhesive (adhesive sheets  25 ,  26 , or otherwise). In this case, one or more splicer plates alone or in combination serve to couple sidewall panels  15 ,  16 . 
     With continued reference to FIG. 2, interior splicer plate  23 , with interior adhesive sheet  25  attached thereto, is couched in recessed region  35  to limit the extent to which it protrudes beyond interior trailer wall surface  38  defined by main plateaus  17 ,  18 . Protrusions beyond interior trailer wall surface  38 , and into the interior region of the trailer, are thus lessened or altogether eliminated. 
     Referring to FIG. 3, after splicer plates  23 ,  24 , with adhesive sheets  25 ,  26  adhered thereto, are sandwiched around seam  32 , rows of rivets  34  are preferably inserted on both sides of seam  32  to further reinforce and strengthen joint  14 . Rivets  34  preferably extend entirely through splicer plates  23 ,  24 , adhesive sheets  25 ,  26 , and sidewall panels  15 ,  16 . Rivets  34  are preferably inserted through these layers only after the layers have been sandwiched together. In this way, adhesive layers  25 ,  26  preferably seal the entire joint  14 , including the holes created by the insertion of rivets  34 . The use of adhesive sheets  25 ,  26  aids in the insertion of rivets  34  through the multiple layer joint  14  without pre-drilling rivet holes in the individual layers. Without adhesive sheets  25 ,  26 , it may be difficult to insert rivets  34  through the sandwiched layers of joint  14  without pre-drilling because panels  15 ,  16  and splicer plates  23 ,  24  may tend to shift as rivets  34  are being punched through the layers. Of course, if desired, it is still possible to partially or fully pre-form rivet holes through the sandwiched layers of joint  14  in any conventional manner prior to riveting the layers together. Adhesive sheets  25 ,  26  also help prevent “puckering” of splicer plates  23 ,  24  as multiple layer joint  14  is being riveted together. To that end, adhesive sheets  25 ,  26  also allow for fewer rivets along seam  32  than would otherwise be required if no adhesive were used. 
     As shown in FIG. 3, rivet heads  42  are preferably also partially or completely couched in recessed region  35  along with interior splicer plate  23  and interior adhesive sheet  25 . Again, recessing rivet heads  42  serves to lessen or eliminate protrusions beyond interior trailer surface  38 . 
     Another preferred embodiment of the present invention is illustrated in FIGS. 4 and 5. The joint illustrated in FIGS. 4 and 5 has a number of features and elements that are similar to features and elements in the embodiment illustrated in FIGS. 1-3. Accordingly, features and elements in the embodiment of FIGS. 4 and 5 that are similar to and correspond to those in the embodiment of FIGS. 1-3 are given the same reference numbers in the  100  series. With the exception of the following description, the above description of the structure, assembly, and elements (and alternative structures, assemblies, and elements) of the joint  14  applies equally to the joint  114  illustrated in FIGS. 4 and 5. 
     As mentioned above, the joint of the present invention can be constructed so that a gap  140  exists between the panels  115 ,  116  of the joint  114 . In many embodiments, the edges of the panels  115 ,  116  abut one another along the panel lengths. In other embodiments however, the panels  115 ,  116  are separated by any desired distance, whether to simplify assembly of the joint  114  or for any other purpose. By way of example only, the panels  115 ,  116  in the joint  114  illustrated in FIGS. 4 and 5 are separated by a gap  140  sufficiently large to permit logistics fasteners, straps, rope, cords, or other cargo securing devices and elements to be attached to the joint  114  between the panels  115 ,  116  as will now be described in greater detail. 
     In order to enable cargo to be secured and/or stabilized within the trailer  10  (or cargo container), the joint  114  preferably has one or more logistics apertures  144 . These logistics apertures  144  are preferably located in at least one of the splicer plates  123 ,  124 , and can take any shape and size desired. For example, the logistics apertures  144  can be rectangular as shown in FIGS. 4 and 5, can have any other polygonal shape, can be round, oval, or irregularly-shaped, and the like. In some preferred embodiments such as that shown in FIGS. 4 and 5, the logistics apertures  144  are elongated in a direction along the length of the joint  114 . Each joint  114  can have any number of logistics apertures  144  arranged in any manner. Preferably however, each joint  114  has a number of logistics apertures  144  aligned or substantially aligned along the joint  114 . 
     A number of different elements and devices can be used to secure and stabilize cargo in a cargo container or trailer. Accordingly, the logistics apertures  144  can be shaped to receive or mate with any such element or device, including clamps, cargo strap ends, buckles, and the like. Therefore, the logistics apertures  144  in some embodiments are shaped to receive, mate with, and/or engage one or more of such elements or devices. Alternatively, the logistics apertures  144  can be shaped to receive one or more such elements or devices (including ropes, cord, chain, cable, and the like) passed into and out of one or more logistics apertures  144 . 
     In some preferred embodiments such as that shown in FIGS. 4 and 5, the splicer plates  123 ,  124  are spaced apart sufficiently to provide room for a cargo-securing device or element to be partially or entirely received within the logistics apertures  144 . In other embodiments however, either or both splicer plates  123 ,  124  have one or more apertures that are at least partially aligned with the logistics apertures  144  in order to permit cargo-securing elements or devices to be received between the splicer plates  123 ,  124 . These apertures can be located in either or both splicer plates  123 ,  124  and can be located entirely within the splicer plates  123 ,  124  or can be open to the edges of the splicer plates  123 ,  124 . In such embodiments, the splicer plates  123 ,  124  can abut one another while still providing apertures located at or near the edges of the splicer plates  123 ,  124  for receiving cargo-securing devices or elements. 
     Logistics apertures  144  can be located in either one or both of the splicer plates  123 ,  124  in order to permit cargo-securing elements to be secured to the joint  114 . In some preferred embodiments such as that shown in FIGS. 4 and 5, logistics apertures  144  are located only on the interior splicer plate  123 . Although a joint  114  having logistics apertures  144  can employ substantially flat interior and exterior splicer plates  123 ,  124  (such as the splicer plates  23 ,  24  employed in the embodiment illustrated in FIGS.  1 - 3 ), the joint  114  more preferably has an enlarged space between the splicer plates  123 ,  124  in order to permit cargo-securing elements or devices to be received within the logistics apertures  144  and between the splicer plates  123 ,  124 . To this end, one or both of the splicer plates  123 ,  124  are preferably shaped to provide this enlarged space. For example, either or both splicer plates  123 ,  124  can be shaped to have one or more channels, troughs, or recesses located between the splicer plates  123 ,  124  for receiving at least part of one or more cargo-securing elements or devices. In the illustrated preferred embodiment of FIGS. 4 and 5, the exterior splicer plate  124  has a trough-shaped section  125  that runs continuously or non-continuously along the length of the exterior splicer plate  124  and that is adjacent to one or more of the logistics apertures  144 . 
     Although a trough-shaped section  125  is preferred in the embodiment of FIGS. 4 and 5, one having ordinary skill in the art will appreciate that any other shape of the exterior splicer plate  125  providing additional space between the splicer plates  123 ,  124  can instead be employed. 
     If desired, adhesive sheets  125 ,  126  can be located between the interior and exterior splicer plates  123 ,  124  and either or both of the wall panels  115 ,  116 . Although adhesive sheets  125 ,  126  are preferred on both sides of the wall panels  115 ,  116 , adhesive sheets  125 ,  126  can instead be located on only the interior side of the wall panels  115 ,  116  or on only the exterior side of the wall panels  115 ,  116  as desired. Similarly, although adhesive sheets  125 ,  126  are preferably located on both wall panels  115 ,  116 , adhesive sheets  125 ,  126  can be located on only one of such wall panels  115 ,  116  as desired. Adhesive sheets  125 ,  126  can span the gap  140  between the wall panels  115 ,  116  (in which case the either or both adhesive sheets  125 ,  126  preferably have apertures through which cargo-securing elements or devices can be received between the wall panels  115 ,  116 ). More preferably however, separate adhesive sheets  125 ,  126  are located on either side of the gap  140 . The adhesive sheets  125 ,  126  can take any of the forms (and alternatives) described above with reference to the first preferred embodiment of the present invention illustrated in FIGS. 1-3. 
     The preferred embodiments described above include an interior splicer plate  23 ,  123 , an exterior splicer plate  24 ,  124 , an interior adhesive sheet  25 ,  125 , and an exterior adhesive sheet  26 ,  126 . However, it will be readily apparent to one of ordinary skill in the art that alternative embodiments of the present invention may instead eliminate one or both adhesive sheets and/or one or both splicer plates to achieve a coupling at joint  14 ,  114  in accordance with the present invention. Additionally, alternative embodiments may employ any number of conventional devices (e.g. belts, biscuits, bolts, brackets, bridges, chains, clamps, clasps, clips, dowels, latches, pegs, pins, posts, screws, etc.) other than splicer plates and rivets to attach fore and aft sidewall panels  15 ,  16 ,  115 ,  116 , while still utilizing recessed region  35 ,  135  to reduce or eliminate protrusions into the trailer interior. Spliced plateaus  19 ,  20 ,  119 ,  120  created by bending or jogging sidewall panels  15 ,  16 ,  115 ,  116  at jogged portions  21 ,  22 ,  121 ,  122  cooperate to form recessed region  35 ,  135 . Recessed region  35 ,  135  may couch any of a number of equivalent devices (including those listed above) for coupling panels  15 ,  16 ,  115 ,  116  still falling within the spirit and scope of this disclosure, including the accompanying claims. 
     The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention as set forth in the appended claims.