Abstract:
A method and apparatus for coupling trailer plates, wherein each plate has a stepped section. At least two trailer plate receiving areas are located on an outward-facing surface of a substantially rectilinear strip. An inward-facing surface of the trailer plate stepped section is coupled to the receiving area on the substantially rectilinear strip.

Description:
FIELD OF THE INVENTION 
     The field of the present invention relates to enclosed trailers and used for the transport of cargo. More particularly, the present invention relates to a plate coupling system for assembling the trailers. 
     BACKGROUND OF THE INVENTION 
     Commercial tractors and other types of trucks transport cargo using trailers such as van-type trailers and other types of enclosed trailers. As illustrated in FIG. 1, a van-type trailer  10  includes a floor  15 , a roof (not shown) and two sidewalls  25 . A front bulkhead  30  and a rear door or doors (not shown) enclose the trailer  10 . A king-pin  40  located at a forward area of the trailer  10  couples to a fifth wheel on a tractor and a conventional wheel assembly  35  and front landing gear  45  support the trailer  10 . 
     Federal regulations specify a maximum width  12  of about 102{fraction (3/8 )}inches for enclosed trailers  10 . Generally, this is measured between the exterior surfaces of the trailer sidewalls  25 . In addition, the transport industry has cargo carrying standards that require a width of about 101¼inches inside the trailer  10 . This width is generally measured between the interior surfaces of the sidewalls  25 . When combined, the Federal and industry requirements define a maximum sidewall thickness  82  of about {fraction (9/16)} of an inch, shown in FIGS. 2-3. The sidewall thickness  82  is therefore constrained by the limits imposed by both the Federal regulations or the industry standards. 
     Illustrated in FIGS. 1-3, the sidewalls  25  of conventional van-type or other enclosed trailers are generally constructed of a plurality of generally rectangular plates  50 . Each plate  50  is connected by elongaged joiners  55 . Fasteners  65  attach the plates  50  to the joiners  55 . FIG. 2 illustrates two plates  50  attached to joiner  55  by fasteners  65 . Also illustrated in FIG. 2, the sidewall thickness  82  is the sum of the plate thickness  85  and the joiner  55  thickness  80 . The outside-facing surface of each joiner  55  is used to define the maximum width of the trailer  10 , and the inside-facing surface of each plate  50  is used to define the inner, or enclosed width of the trailer  10 . 
     When the outside-facing surface  70  of each joiner  55  defines the maximum Federally regulated width of the trailer  10 , and the inside-facing surface of each the plate  50  defines the minimum industry standard inner width of the trailer  10 , if the plate thickness  85  or the joiner thickness  80  is changed, the other member must change to maintain the necessary sidewall thickness  82 . For example, it may be advantagous to add a cargo control member to the sidewall  25 . A cargo control member is an elongated plate having a plurality of holes and/or slots for attaching straps, hooks and other devices to position and secure the cargo within the trailer  10 . Illustrated in FIG. 3, the inclusion of a cargo control member  60  requires a plate thickness  87  that is smaller than the plate thickness  85  of FIG.  2 . The larger joiner thickness  89  maintains the required sidewall thickness  82 . A thinner sidewall  25  cannot be used, as it does not have the structual strength necessary to restrain the cargo during transportation. 
     Alternatively, a thicker plate  50  may be installed to increase the structural strength of the sidewall  25  in the area adjacent to the cargo-loading end of the trailer  10 . The trailer  10  opening where cargo is loaded can sustain impacts from the cargo or from fork-loaders placing the cargo into the trailer  10 . In this instance, the thickness of the joiner  55  must be reduced. Mounting two different thickness plates  50  to one joiner  55  also requires a special joiner  55  because an outside-facing shoulder is created where the different thickness plates  50  meet. The shoulder cannot face the interior of the trailer  10  as it becomes a “snag” point, causing damage to cargo and causing the plates  50  to be more easily damaged. The special joiner  55  must be designed to accommodate that shoulder. Thus, for conventional plate coupling systems, when the plate  50  increases in thickness the joiner  55  must decrease in thickness to maintain the necessary sidewall thickness  82 . 
     During service, the trailer sidewalls  25  can be damaged, requiring replacement of plates  50 , joiners  55 , or both. FIG. 4 illustrates a section of sidewall  25  constructed of three plates  50  fixed to two joiners  55  using four rows of fasteners  65 . In FIG. 4A, replacement of a plate  50  is illustrated. The plate  50  must be removed from the outside of the trailer  10 , because the plate  50  extends past the ceiling and floor  15  of the trailer  10  interior. Thus, both joiners  55  must be removed to remove one plate  50 . This requires the removal of four rows of fasteners  65 . The time and effort necessary to remove four rows of fasteners  65 , and two joiners  55  is significant, which reduces trailer availability, negatively affecting cargo delivery schedules. 
     FIGS. 5 and 5A illustrate a section of sidewall  25  constructed of three plates  50  fixed to two joiners  55  by four rows of fasteners  65 , with logistics members  60 . In this arrangement, the four rows of fasteners  65 , both joiners  55  and both logistics members  60  must be removed to replace the plate  50 . Again, this requires substantial time and effort, resulting in trailer downtime. 
     Therefore, there exists a need for a trailer plate construction system that permits quick replacement of damaged plates and enables the use of thick plates without exceeding Federal regulations while meeting industry cargo carrying standards. 
     SUMMARY OF THE INVENTION 
     In order to overcome the deficiencies with known, conventional plate construction systems, a method and apparatus for coupling trailer plates is provided. Briefly, the plate-coupling system of the present invention includes a stepped section located on at least one side of a substantially rectangular trailer plate and an elongated coupler having a plate receiving area. The plate receiving area is configured to receive the trailer plate stepped section. 
     More specifically, one embodiment of the plate-coupling system employs a substantially rectilinear coupling member comprising an inward-facing and an outward-facing surface. At least two trailer plate receiving areas are located on the outward-facing surface of the rectilinear coupling member. The trailer plate receiving areas are arranged to receive an inward-facing surface of a stepped section of a trailer plate. As defined herein, the outside-facing surface is the surfaces that faces the exterior of the trailer and the inside-facing surface is the surface that faces the interior of the trailer. 
     Advantageously, the trailer plate coupling system according to the present invention allows the use of increased thickness plates without exceeding Federal trailer width standards. With the present invention, increases in plate thickness do not push the coupling member outward, but rather, the plate is pushed outward. However, the outward-facing surface of the plate does not exceed the outward-facing surface of the coupling member, thereby maintaining a sidewall thickness that meets the Federal regulations and industry standards. 
     The coupling system according to the invention also permits quick replacement of damaged plates by requiring the removal of the damaged trailer plate only. The coupling member remains attached to the trailer sidewall. 
     In addition, the coupling system according to the invention also permits plates of different thickness to be coupled adjacent to each other, without the need for special coupling members. Moreover, the coupling system according to the invention can also be used in the construction of intermodal containers, and shipping containers. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The nature, goals, and advantages of the invention will become more apparent to those skilled in the art after considering the following detailed description when read in connection with the accompanying drawing in which like reference numerals identify like elements throughout wherein: 
     FIG. 1 is a perspective view of a conventional plate trailer; 
     FIG. 2 is a sectional view taken along the line  2 — 2  in FIG. 1; 
     FIG. 3 is a sectional view taken along the line  3 — 3  in FIG. 1; 
     FIG. 4 is a sectional view taken along the line  4 — 4  in FIG. 1; 
     FIG. 4A is a sectional view depicting the removal of a trailer plate illustrated in FIG. 4; 
     FIG. 5 is a sectional view taken along the line  5 — 5  in FIG. 1; 
     FIG. 5A is a sectional view depicting the removal of a trailer plate illustrated in FIG. 5; 
     FIG. 6 is a perspective view of a plate trailer constructed according to the present invention; 
     FIG. 7 is a sectional view taken along the line  7 — 7  in FIG. 6, illustrating one embodiment of the present invention; 
     FIG. 8 is a sectional close-up view of the embodiment of FIG. 7; 
     FIG. 9 is a sectional view taken along the line  9 — 9  in FIG. 6, illustrating another embodiment of the present invention; 
     FIG. 10 is a sectional close-up view of the embodiment of FIG. 9; 
     FIG. 11 is a sectional view taken along the line  11 — 11  in FIG. 6, illustrating a third embodiment of the present invention; 
     FIG. 12 is a sectional close-up view of the embodiment of FIG. 11; and 
     FIG. 13 is a sectional view depicting the removal of a trailer plate illustrated in FIG.  11 . 
    
    
     It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown. 
       
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following paragraphs, the present invention will be described in detail by way of example with reference to the attached drawings. Throughout this description, the preferred embodiment and examples shown should be considered as exemplars, rather than as limitations on the present invention. 
     The disclosed examples of the invention provide an enclosed stepped plate trailer  70 , illustrated in FIG. 6, having stepped plate sidewalls  75 , with the stepped plate sidewalls  75  constructed by connecting several stepped plates  97 . Advantageously, the stepped plates  97  may be thicker than in known trailers, thereby providing advantageous strength and reliability. In addition, different thickness stepped plates  97  can be mounted directly adjacent to each other. Generally, each stepped plate  97  is connected to an adjacent stepped plate  97  by a coupler  90 . As described, each stepped plate  97  is substantially rectangular, with a top, a bottom and two side edges. The coupler  90  is a substantially elongated strip with a short top and a short bottom, with two long side edges. 
     Referring to FIGS. 7 and 8, a cross-sectional view of one embodiment of the trailer plate coupling system  120  according to the present invention is illustrated. The substantially rectangular stepped plate  97  comprises a stepped section  100  located along a side edge of the plate  97 . The stepped section  100  forms a raised area that extends at least along a majority of the side edge of plate  97 . The stepped section  100  is structured to mate with a complementary flange  95  that extends from a coupler  90 . Preferably, the stepped section is integerally formed with the rest of the plate  97 . For example, the stepped section  100  may be formed by bending a recess into a side edge of the plate  97 . It will be appreciated that other techniques can be used to form the stepped section  100 , or that the stepped section  100  can be formed from discrete parts and joined together. The stepped plate  97  can be constructed of one aluminum plate, two sandwiched aluminum plates with a honeycomb interior, or two sandwiched steel plates with a plastic, or other suitable material positioned between the steel plates. It will be appreciated that other materials can also be employed to construct the stepped plate  97 . 
     The coupler  90  includes a central body  92  from which the flanges  95  extend, and a slot  105  located between the flange  95  and the body  92  for receiving a sealant (not shown) for preventing moisture intrusion into the stepped plate trailer  70 . It will be appreciated that the flange  95  could be any complementary mating structure, such as a lip, arm, tab or other suitable structure. Preferably, the coupler  90  is constructed of extruded aluminum, but it will be appreciated that other materials and processes can be used to construct the coupler  90 . 
     A fastener  65  attaches the stepped section  100  of the stepped plate  97  to the coupler  90  flange  95 . Preferably, the fastener  65  is a rivet but it will be appreciated that other types of fasteners such as bolts, screws, pins and other suitable fasteners could be used. In addition, attachment of the stepped plate  97  to the coupler  90  could be accomplished by glues, epoxies and other suitable types of attachment methods. 
     Illustrated in FIGS. 7 and 8, an outside-facing surface of the flange  95  mates with the inside-facing surface of the stepped section  100 . As defined herein, an outside-facing surface is the surface that faces the exterior of the trailer stepped plate  70  and an inside-facing surface is the surface that faces the interior of the trailer stepped plate  70 . In contrast to conventional arrangements, where the outside-facing surface of the plate  50  meets the inside-facing surface of the joiner, shown in FIGS. 2-5A, the invention places the outside-facing surface of the coupler  92  in contact with the inside-facing surface of the stepped plate  97 . 
     Referring to FIGS. 9 and 10, a cross-sectional view of an alternative embodiment of the present invention is illustrated. The coupler  90  has a central body  92  that includes ribs  110  for supporting a cargo control panel  115 . It will be appreciated that alternative embodiments of the coupler  90  may not include the ribs  110 . The cargo control panel  115  faces the inside of the stepped plate trailer  70  and contains slots and/or holes for securing hooks, bars, straps, or other types of devices for positioning and securing the cargo to the interior of the stepped plate trailer  70 . Alternatively, a reinforcement plate (not shown) can replace the cargo control panel  115 . The reinforcement plate is substantially identical to the cargo control panel  115  except that it does not contain any holes and/or slots for the cargo control devices. The reinforcement plate increases the structual strength, or bending stiffness of the coupler  90 . The cargo control panel  115  also increases the structual strength of the coupler  90 , but to a lesser degree than the reinforcement plate because of the holes and slots that are cut out of the cargo control panel  115 . 
     In the embodiment illustrated in FIGS. 9 and 10, the stepped plate  97  has a stepped section  100  that is attached to the coupler  90  by fasteners  65 . Illustrated in FIG. 10, the flange  95  has a slot  105  for receiving sealant and a flange tip  96  that prevents cargo from catching on the edge of the reinforcement or cargo control panel  115 . It will be appreciated that alternative embodiments of the coupler  90  may not include the flange tip  96 . Also illustrated in FIG. 10, an inside-facing surface of the panel  97  engages an outside-facing surface of the coupler  90 . 
     FIGS. 11 and 12, illustrate a cross-sectional view of a third embodiment of the present invention. The coupler  90  includes an extended flange  95  that accommodates two fasteners  65  on each flange  95 . A reinforcement or cargo control panel  115  is secured by two fasteners  65  and another pair of fasteners  65  attach the panel  97  to the coupler  90 . In FIG. 12, slot  105  is illustrated, which may receive sealant for preventing moisture intrusion into the stepped plate trailer  70 . 
     Generally, construction of a sidewall  75  according to the present invention will begin with the forming a stepped section  100 . This can be accomplished by employing a stamping process, or other suitable process. It will be appreciated that other methods and processes can be used to form the stepped section  100 . After forming, the stepped section  100  is placed adjacent to the coupler  90 , with the stepped section  100  located over the flange  95 . Fasteners  65  are inserted through corresponding holes in both the stepped section  100  and flange  95 , thereby joining the stepped plate  97  to the coupler  90 . 
     FIG. 13 illustrates the replacement of a damaged stepped plate  97 . In contrast to conventional replacement procedures, illustrated in FIGS. 4A and 5A, replacement of a stepped plate  97  only requires removal of the stepped plate  97 —not the adjacent couplers  90 . In this embodiment, two rows of fasteners  65  are removed, and couplers  90  remain attached to the stepped plate sidewall  75 . Hence, the number of fasteners  65  that must be removed is reduced by 50% when compared to conventional replacement procedures. Similarly, only half the number of fasteners  65  must be reinstalled when attaching a new stepped plate  97 . This translates into a significant reduction in the amount of time and effort required to replace damaged plates, thereby decreasing trailer repair time. 
     In addition to simplification of repair, the present invention possesses several other advantages. For example, in conventional trailer construction systems, any change to the thickness of the plate  50  or the joiner  55  requires a corresponding change to the thickness of the other member, as shown in FIGS. 2-3. This is necessary because of the strict sidewall thickness  82  requirements imposed by industry standards and Federal regulations. With conventional trailer plate joining systems the joiner  55  is pushed outward, or away from the stepped plate trailer  70  when thicker plates  50  are installed. This is because the joiner  55  mounts to the outside-facing surface of the plate  50 . Put differently, the joiner  55  is positioned on top of the plate  50 . 
     However, this is not the case in the present invention. Referring to FIG. 7, the stepped plate  97  is positioned on top of the coupler  90 . That is because the inside-facing surface of the stepped plate  97  mounts to the outside-facing surface of the coupler  90 . Therefore, the outside-facing surface of the stepped plate  97  is pushed outward, or away from the stepped plate trailer  70  when a thicker stepped plate  97  is installed. Therefore, the thickness of the sidewall measured from the inside-facing surface of the stepped plate  97  to the outside-facing surface of the coupler  90  does not change because, as illustrated in FIGS. 7 and 8, the coupler body  92  is the thickest part of the stepped plate sidewall  75 . Generally, the coupler body thickness  94  can range from about 0.4 inches to about 0.563 inches, and the stepped plate thickness  98  can range from about 0.06 inches to about 0.2 inches. 
     Employing the above-described stepped plate system, changes to the thickness of the stepped plate  97  can be made without changing the thickness of the coupler  90 . In operation, the thickness of the stepped plate  97  can increase until the outside-facing surface of the stepped section  100  aligns with the outside-facing surface of the coupler body  92 . Therefore, stepped plates  97  of substantial thickness can be attached to the coupler  90  without exceeding the stringent sidewall thickness  82  demanded by federal regulations and industry standards. 
     In addition, the present invention now allows for stepped plates  97  of different thickness to be mounted directly adjacent to each other. This feature is advantageous because thick stepped plates  97  can be mounted near the open-end of the stepped plate trailer  70 , or in high-stress areas such as around the kingpin  40 , landing gear  45 , or in areas used to lift the trailer  70 , where increased structural strength is desired. Thinner stepped plates  97  can be used in the remaining areas of the stepped plate trailer  70 , thereby reducing construction cost and trailer weight. 
     One skilled in the art will appreciate that the present invention can be practiced by other than the preferred embodiments which are presented in this description for purposes of illustration and not of limitation, and the present invention is limited only by the claims that follow. It is noted that equivalents for the particular embodiments discussed in this description may practice the invention as well.