Patent Publication Number: US-2005127714-A1

Title: Multi-compartment semi-trailer for transport of recyclable materials

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application is a continuation-in-part application of application Ser. No. 10/737,564, filed Dec. 16, 2003. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
      Not Applicable  
     BACKGROUND OF THE INVENTION  
      1. Field of Invention  
      This invention pertains to transport vehicles for moving recyclable materials long distances. More particularly, this invention pertains to a semi-trailer for contained transport of salvageable vehicles and bulky recyclable materials.  
      2. Description of the Related Art  
      As prices for recyclable salvage materials escalate, salvage materials are being transported over significantly greater distances on public roads. Prior transport vehicles include flat-bed trucks and semi-trailers lacking walls on which crushed vehicle bodies and other bulky recyclable materials are stacked and secured by chains and cables. Due to the increasing frequency of mishaps involving damage to public vehicles by ejection of debris from flat-bed trucks and semi-trailers lacking side walls, the U.S. Department of Transportation has developed regulations requiring transport of salvageable vehicles to be contained by a transport vehicle having side walls when moved on public roads.  
      Prior methods of transport of refuse and recyclable materials over short distances in local communities include trucks having individual hoppers accessible from a perimeter of the vehicle, or dump trucks having an open bay in which materials were dumped by auxiliary equipment (see U.S. Pat. No. 6,309,164). For long distance transport of refuse and recyclable materials, dump trucks have typically been utilized with no covering over the materials. The above described vehicles are typically not adequately sized to accept crushed vehicles or other bulky recyclable materials that are efficiently loaded and unloaded utilizing a forklift system and/or an overhead crane system. Flat-bed rail cars have been utilized for transport of refuse and recyclable materials contained in boxes mounted on the flat-bed rail cars, or flat-bed rail cars have been utilized to transport crushed vehicles stacked and secured by chains or straps thereon. Typical rail cars utilized for hauling refuse have included cars having four side walls and an enclosing top wall, with one or opposed side doors being slid sideways to provide a side opening for loading and unloading of refuse. For typical rail cars which utilize a side door rigidly attached to a covering top wall, when the side door and top wall are opened, the side door is limited in movement therefore obstruction of the side door opening occurs (see U.S. Pat. No. 5,488,911). Further, an enclosing top wall for a rail car does not allow overhead access for loading and unloading of the rail car contents from overhead by a crane.  
      An improved transport vehicle is needed to meet federal regulations for containment of salvageable vehicles and other bulky recyclable materials during towed transport. Further, an improved semi-trailer transport vehicle is needed to provide compartments for containment of salvageable vehicles segregated from other recyclable materials during towed transport of the semi-trailer while offering efficient loading and unloading of salvageable vehicles and other recyclable materials due to unobstructed side access or unobstructed overhead access with a minimum of movement of sidewalls. In addition, a semi-trailer is needed having reduced trailer weight while maintaining trailer platform rigidity in order to increase carrying capacity for salvageable materials stored in compartments on the semi-trailer.  
     BRIEF SUMMARY OF THE INVENTION  
      According to one embodiment of the present invention, a semi-trailer is provided for transporting salvageable materials to one or more processing facilities. The semi-trailer includes a platform having multiple compartments thereon and supported by a wheeled undercarriage for towed transport. The platform includes a first sidewall extended along a first side and a second sidewall extended along a second side of said platform, with each sidewall having upper portions extended upwardly to bound an open top of sufficient width separation to receive salvageable materials therein. Front and rear end walls are extended between the first and second sidewalls, and a partition wall is spaced apart between the front and rear end walls, with the partition wall being oriented for separation of the platform into a forward compartment and a rearward compartment.  
      The second sidewall is mounted for clamshell movement between a closed position aligned along the second side of the platform and substantially parallel with the first sidewall, to a raised position above the platform. The second sidewall includes front and rear upper support segments extended laterally across the platform width. Each front and rear upper support segment is disposed laterally adjacent with respective front and rear end walls. Each support segment includes respective front and rear connecting ends pivotably mounted to respective front and rear upper portions of the first sidewall. The second sidewall also includes a middle upper support segment extended laterally from a middle of the second sidewall and is positioned adjacent the partition wall on the platform.  
      A lifting mechanism is utilized for movement of the second sidewall from the closed position to a raised position above the platform. Movement to the raised position provides unobstructed side access to either of the forward and rearward compartments for loading and unloading of salvageable materials. Movement to the closed position provides for containment and segregation of salvageable materials during towed transport to processing facilities.  
      With the second sidewall positioned in the closed position, the separation between each first and second sidewall provides each compartment with an open top of sufficient width and length to receive salvageable materials in either compartment from an overhead delivery mechanism. In order to reduce the unloaded weight of the semi-trailer and thereby increase the load capacity for transport of salvageable materials during each trip, the first sidewall, the front and rear end walls, and the second sidewall include light-weight materials extending between upper and lower frame members and having a plurality of spaced-apart studs extending upwardly relative to the platform when the second sidewall is in the closed position. The first sidewall, the front and rear end walls, and the second sidewall further include generally continuous exterior surfaces which are composed of a mesh material supported by the plurality of spaced-apart studs, with the mesh material allowing air flow therethrough during transport and providing a lesser unloaded weight for the platform in comparison to solid metal sidewalls and end walls. Loose salvageable materials generated during loading or transport are retained within the respective compartments regardless of air flow through the compartments during towed transport thereby protecting other vehicles traveling near the platform during towed transport over public roads. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
      The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:  
       FIG. 1  is a perspective view of a semi-trailer of the present invention having multiple compartments in which salvageable materials are segregated;  
       FIG. 2  is a perspective view of  FIG. 1 , illustrating the movable sidewall in a raised position for side loading into either compartment of the semi-trailer;  
       FIG. 3A  is a rear view of  FIG. 1 , illustrating the movable sidewall in a closed position with a rear lifting mechanism disposed in a non-extended position;  
       FIG. 3B  is a rear view of  FIG. 3A , illustrating the movable sidewall in the elevated position with the rear lifting mechanism in an extended position;  
       FIG. 4  is an exploded view of an upper corner pivot connection of  FIG. 3B , illustrating an upper rear support segment providing for reciprocating movement of the second sidewall;  
       FIG. 5  is an exploded view of an upper rear connection joint of  FIG. 3B , illustrating an extendable piston attachable to a mid-portion of the rear support segment of the second sidewall;  
       FIG. 6A  is a cut-away view of a middle lifting mechanism enclosed within a middle partition wall and with the second sidewall in the closed position;  
       FIG. 6B  is an exploded view of an upper connection joint and a middle piston extended to an elevated position; and  
       FIG. 7  is a side view of  FIG. 2  with the second sidewall in the raised position, illustrating the middle partition wall having a lifting mechanism therein. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      In accordance with the present invention, a semi-trailer  100  having multiple storage compartments  110 ,  110 ′ is provided for contained transport of salvageable materials such as crushed vehicles  192 ,  192 ′,  192 ″ and other bulk recyclable materials  194  to processing facilities. Unobstructed side access is provided to the storage compartments  110 ,  110 ′ by mounting a pivotable second sidewall  134  for clamshell movement between a closed position  140 ′ and a raised position  140  above the platform  116 . With the pivotable sidewall  134  in the closed position, the semi-trailer  100  is towed by connection to a tractor-truck sized to provide adequate towing capacity of up to about a twenty ton load capacity for the platform  116  mounted on a multi-wheeled undercarriage  112  (see  FIGS. 1 and 2 ). The platform  116  includes an adequate width between a first side  116 ′ from a second side  116 ″ for positioning thereon a plurality of crushed vehicles  192 ,  192 ′,  192 ″, either through an open top  136 ′ with the pivotable sidewall  134  closed, or by side access along the second side  116 ″ with the pivotable sidewall  134  raised (see  FIGS. 1 and 2 ).  
      In order to retain size-reduced recyclable materials on or in a semi-trailer  100  during transport over public roads, a fixed first sidewall  130  forms a first containment wall extending vertically along the length of the platform first side  116 ′ from a front end  118  to a rear end  120  (see  FIGS. 2 and 3 A). The first sidewall  130  is extended for a height above the platform  116  of between about 8 feet 6 inches, for a total height above the ground of about 13 feet 6 inches in one embodiment. The height of the first sidewall  130  is constructed to be an adequate height above the platform  116  to retain the flattened profiles of each upper-most stacked crushed vehicle  192 ,  192 ′ or  192 ″, at a height of approximately equal to, or lower than, the height of a lengthwise oriented upper frame  132  of the first sidewall  130 . The platform  116  further includes a fixed front end wall  122  and a fixed rear end wall  124  aligned generally parallel with each other and spaced apart a sufficient length to accommodate therebetween a plurality of recyclable materials in various shapes. An end-to-end platform length extending between end walls  122 ,  124  is about forty feet to about forty-one feet. The front end wall  122  and rear end wall  124  are joined along respective base portions to the platform  116 . Rigid corner studs are required to support the pivoting ends of the second sidewall  134 , including a wall front corner member  122 ′″ and a rear corner member  124 ′″ positioned at respective front and rear corners of a lower frame  132 ′ of the first sidewall  130 . The upper frame edges  122 ″,  124 ″ of the mid-portion of respective front and rear end wall support studs  122 ,  122 ″,  124 ,  124 ′ are angled downwards toward the platform second side  116 ″, thereby providing a lower height threshold for lifting salvageable materials over either front or rear end wall support studs  122 ,  122 ″,  124 ,  124 ′ when loading or unloading across the platform second side  116 ″ by a forklift  190  (see  FIG. 2 ) or other lifting and loading device. The first sidewall  130  and substantially upright wall support studs  122 ,  122 ″,  122 ′″,  124 ,  124 ′,  124 ′″ are positioned as a plurality of steel or aluminum support members  130 ′″,  130 ″″ spaced apart along each sidewall and platform ends, to provide rigid containment walls for recyclable materials stacked on the platform  116 . Two open tops  136 ′,  136 ″ are provided to allow a plurality of crushed vehicles  192 ,  192 ′,  192 ″ and/or other recyclable materials  194  to be loaded or unloaded into either or both storage compartments  110 ,  110 ′ from overhead by appropriate equipment positioned proximal of the platform  116  with the second sidewall  134  in a closed position  140 ′.  
      During towed transport of the semi-trailer  100 , the pivotable second sidewall  134  is positioned in a closed position  140 ′ in which a base frame member  138  is disposed adjacent the length of the platform second side  116 ″, and the second sidewall  134  is extended substantially parallel to the first sidewall  130  (see  FIGS. 1 and 3 A). The second sidewall  134  is pivotably disposed to a raised position  140  above the platform  116  (see  FIGS. 2, 3B ,  6 B and  7 ), by at least one lifting mechanism  150  powered in one embodiment by a hydraulic power system including one rear motor  160  and/or a front motor  160 ′ which are controlled by an operator when the semi-trailer  100  is stationary. One skilled in the art will recognized that the lifting mechanism  150  can include a hydraulic system that is pressurized by power generated by the engine of a tractor-truck, or the lifting mechanism  150  can include a pneumatic air system that is supplied by a pressurized system utilized by a tractor-truck designed to pull a semi-trailer.  
      The second sidewall  134  includes an upper frame  136  extended between an upper corner of an upper front support segment  142  and an upper corner of an upper rear support segment  144 . When in the closed position  140 ′, the upper front support segment  142  has a pivot connector end  142 ′ extended adjacently parallel above the front end wall  122 , and the upper rear support segment  144  has a pivot connector end  144 ′ extended adjacently parallel above the rear end wall  124 . Both connector ends  142 ′,  144 ′ are configured to extend laterally about eight feet to traverse the platform width and to connect pivotably at respective front and rear pivot junctions  126 ′,  128 ′ proximal of the upper front and rear corners of the first sidewall  130 . When in the raised position  140 , the movable front support segment  142  is raised into a cantilevered position above the front end wall  122 , and the movable rear support segment  144  is raised into a cantilevered position above the rear end wall  124 , thereby providing unobstructed access for loading and unloading of either the front and rear storage compartments  110 ,  110 ′.  
      In order to reduce the unloaded weight of the semi-trailer  100  thereby increasing the capacity for recyclable materials, the outer surfaces  196  of the first sidewall  130 , the pivoting sidewall  134 , and the front and rear wall segments  122 ,  142 ,  124 ,  144 , can be composed of a mesh or lattice material allowing air flow therethrough. By utilizing a mesh or lattice material covering the first sidewall, the front and rear end walls, and the pivoting sidewall  134 , the gross weight of the semi-trailer  100  is reduced by approximately 5,000 pounds, while retaining structural integrity of the side walls by utilizing a plurality of spaced-apart studs  130 ′″,  130 ″″ to support the mesh or lattice materials. Typical materials utilized for the outer surfaces  196  include a fabric tarp, a high-density plastic mesh, or a lattice material composed of steel, aluminum or synthetic polymer materials. The outer surfaces  196  of the mesh or lattice materials are supported by a plurality of spaced-apart studs  130 ′″,  130 ″″ positioned between the major sidewall structural support members of the semi-trailer  100  including corner support members  122 ′″,  124 ′″,  126 ,  128 , and cross-member supports  142 ′,  144 ′,  174 ′ (discussed herein). A sidewall support member at the front corner  126  and back corner  128  of the first sidewall  130 , and at the front corner member  134 ′ and rear corner member  134 ″ of the second sidewall  134  (see  FIGS. 1 and 7 ), are preferably composed of rigid materials such as steel, aluminum, or similar structural materials to provide adequate support for the outer surfaces  196  extended therebetween, and to support second sidewall  134  during movement. The sidewalls  130 ,  134  can include horizontal cross-members  130 ″,  138 ″ extended between respective studs  130 ′″,  130 ″″ to increase sidewall rigidity.  
      A middle partition  170  is incorporated in the semi-trailer  100  for separation of the trailer storage area into at least two storage compartments  110 ,  110 ′ on the platform  116 . By providing at least two storage compartments  110 ,  110 ′, the semi-trailer  100  can be utilized for segregation of a plurality of crushed cars  192 ,  192 ′,  192 ″ from other large recyclable materials  194  having a separate destination or requiring alternative recycling. The middle partition  170  is formed by a fixed partition wall  172  having a “u-shaped” cross-section when viewed from above, and having an interior cavity  178  opening outwardly and laterally toward the second, loading side  116 ″ of the platform  116 . The fixed partition wall  172  includes a base portion originating against the floor of the platform  116 , and at least one inspection door  170 ′ on a rearward side of the fixed partition wall  172 . The inspection door  170 ′ provides access into the interior cavity  178  from the rear storage compartment  110 ′ to allow maintenance to a middle lifting cylinder  180  if utilized and positioned within the cavity  178  (see  FIGS. 6A and 6B ).  
      Pivotably disposed laterally adjacent of the fixed partition wall  172  is a movable middle partition  174  having a triangular surface area forming a central body of the middle partition  174 . One embodiment provides the middle partition  174  in planar alignment above the fixed partition wall  172  when the second sidewall  134  is in the closed position  140 ′ (see  FIG. 6A ). The fixed partition wall  172  includes a first wall portion  172 ′ attached to the first wall upper frame member  132  and having an upper surface angled downwardly to the platform second side  116 ″ (see  FIG. 6B ). The fixed partition wall  172  further includes a second wall portion  172 ″ aligned adjacent with the first portion  172 ′ and also angled downwardly to the platform second side  116 ″. When in the closed position  140 ′, a leading edge  138 ′ of the base frame  138  portion of second sidewall  134  is positioned proximal to the lower sides of each first and second wall portion  172 ′,  172 ″ (see  FIG. 6A ). When the movable middle partition  174  is raised into a cantilevered position above the fixed partition wall  172 , side access is provided to the cavity  178  housing a middle lifting cylinder  180 , if utilized. The fixed partition wall  172  and the movable middle partition  174  are preferably manufactured of steel or aluminum to provide a middle partition  170  contributing structural rigidity at about a mid-portion of the first sidewall  130  to support the movable middle partition  174  attached to second sidewall  134 .  
      In order to provide additional lifting support to the lifting mechanism  150  for lifting the pivotable second sidewall  134 , the movable middle partition  174  can be supported by an optional middle lifting cylinder  180  positioned in the cavity  178  (see  FIGS. 6A and 6B ). The middle lifting cylinder  180  includes a pivotable base  180 ′, a piston rod  182  extendable from the lifting cylinder  180 , an upper bracket  184  connected to a mid-portion of the movable middle partition  174 , a connector pin  186  for attaching the bracket  184  to piston rod  182 . In addition, sufficient linkages such as hydraulic hoses or pneumatic conduits  188  are provided to supply power, whether hydraulic fluid or pneumatic pressure, from the lifting cylinder  180  to a power supply (see  FIG. 6B ). The upper bracket  184  connects to the pivotable middle partition  174  which extends to a pivot end  174 ″ releasably connected to a pivot junction  176  formed with the upper corners of the fixed partition wall first and second portions  172 ′,  172 ″. Pivot end  174 ″ is inserted in a tongue and groove configuration in junction  176  for movement of middle partition  174  relative to the fixed partition wall  172  when an operator actuates the lifting mechanism.  
      The upper frame  132  of the first sidewall  130  and the upper frame  136  of the second sidewall  134  provide a boundary for an open top  136 ′ allowing top loading access to a significant interior volume of contained space. The two or more compartmental areas  110 ,  110 ′ provided by the semi-trailer  100  is bounded by the length of the first sidewall  130 , the front end wall  122  having the upper front support segment  142  aligned thereon, the rear end wall  124  having the upper rear support segment  144  aligned thereon, and the second sidewall  134  when disposed in the closed position  140 ′. The interior volume provided by the trailer  100  with the second sidewall  134  closed is in a range of between about 2,798 cubic feet to about 3,250 cubic feet, depending on a height of the walls surrounding the platform  116  extended between the first sidewall  130  and the second sidewall  134 . A preferred configuration of the first sidewall  130  and second sidewall  134  when in the closed orientation enclosing the platform  116  includes a height extending above the platform  116  of about 8 feet 6 inches high for the first sidewall  130  and second sidewall  134  in the closed position  140 ′, with inside widths of about 8 feet wide for the front and rear end walls  122 ,  124 , and an inside length of about 41 feet 6 inches between the front and rear end walls  122 ,  124 .  
      The front pivot connector end  142 ′ of upper front support segment  142  is pivotably mounted by connection with at least one connector pin  142 ′″ to an offset pivot junction  126 ′ proximal of the upper front corner  126  of the front end wall  122  in the same manner as illustrated in  FIG. 4 . The rear pivot connector end  144 ″ of upper rear support member  144 ′ is pivotably mounted by connection with at least one connector pin  144 ′″ to an offset pivot junction  128 ′ proximal of the upper rear corner  128  of the rear end wall  124  (see  FIGS. 1 and 4 ). With the second sidewall  134  in the closed position  140 ′, the upper front support member  142  is positioned adjacently above the front end wall  122 , and the upper rear support member  144  is positioned adjacently above the rear end wall  124 , with the combined height extending a sufficient height above the platform  116  to provide for enclosure of a plurality of stacked crushed vehicles  192 ,  192 ′,  192 ″ up to a height of about eight feet, six inches above the platform  116 . When pivoted in a clamshell movement to the raised position  140 , the elevated second sidewall  134  provides an unobstructed length of the second side  116 ″ to allow rapid loading and stacking, and rapid unloading of crushed vehicles  192 ,  192 ′,  192 ″ and other recyclable materials  194  on or off the platform  116 .  
      The upper front support segment  142  and upper rear support segment  144  are shaped to have a substantially triangular width when viewed from a forward or rearward position of the rear or front ends of the semi-trailer  100 . Each of the upper support member connector arms  142 ′,  144 ′ and  174 ′ are generally rigid and include a reinforced central gusset member extended downwardly from each connector arms in a generally triangular shape. The central gusset member includes arcuate lower edges which align with and contact against an upper edge of respective front end wall  122  and rear end wall  124  when the second sidewall  134  is positioned in the closed position  140 ′. An upper corner of the front support segment  142 , specifically the front pivot connector end  142 ′, is pivotably attached proximal of the front upper corner  126  of the first sidewall  130  and the front end wall  122 . The front upper corner  126  is disposed at a height of between about eight feet to about eight feet and six inches above the platform  116 . The rear upper corner  128  is disposed at a height of between about eight feet to about eight feet and six inches above the platform  116 , and includes rear pivot connector arm  144 ′ as illustrated in  FIGS. 3A and 3B . The second and lesser height of a second front end wall corner  126 ″ and a second rear end wall corner  128 ″ is between about a third or a half of the first height, providing end wall heights of between about four feet to about six feet above the platform  116 . The lesser height of the end wall corners  126 ″,  128 ″ provide a lower threshold for lifting salvageable materials over either front or rear end wall proximal of the platform second side  116 ″ (see  FIG. 2 ).  
      The lifting mechanism  150  provides for movement and positioning of the second sidewall  134  between closed  140 ′ and open, elevated  140  positions. A preferred embodiment includes a pair of lifting systems positioned exterior of each front end wall  122  and rear end wall  124 . At least one rear lifting system  152  includes a cylinder body  154  having a piston arm  156  extendable therefrom, and includes a cylinder base  154 ′ pivotably mounted on the exterior surface of the rear end wall  124  at about a mid-portion of the base width of the rear end  120  of the platform  116  (see  FIGS. 3A and 3B ). The rear lifting system  152  includes a piston arm  156  extended to a distal end  156 ′ that is pivotably connected utilizing a pin  156 ″ to an upper connection  146  fixed to the upper support member connector arm  144 ′ of the upper rear support segment  144  (see  FIGS. 3A, 3B  and  5 ).  
      For one embodiment of the lifting mechanism  150 , at least one front lifting system  162  (see  FIG. 7 ) is included having a cylinder body  164  from which a piston arm  166  is extendable, and having a cylinder base  164 ′ that is pivotably mounted on the exterior surface at about a mid-portion of the base width of the front end wall  122  in a configuration similar to that illustrated in  FIGS. 3A, 3B  and  5 ). The front lifting system  162  includes a piston arm  166  extended to a distal end  166 ′ that is releasably connected by pivot pin  166 ″ to a front mid-wall connection  148  fixed to an upper mid-portion of front upper support segment  142 . A second front cylinder and piston can be utilized (not shown) proximal of the first front hydraulic cylinder  164  and piston  166  for synchronous movement to the raised position  140  of the front upper support segment  142  of a heavily weighted upper frame  136  and second side wall  134 . The rear and front lifting systems  152 ,  162  are supplied with hydraulic power by hydraulic linkages providing pressurized hydraulic fluid transmitted by a plurality of hydraulic hoses  158 ,  168  in fluid connection with a hydraulic power system and at least one motor  160  of approximately six horsepower power output and positioned proximal of the platform rear end  120 . An auxiliary motor  160 ′ can be positioned on the platform front end wall  122  (see  FIG. 6 ). The plurality of hydraulic hoses  158 ,  168 ,  188  are detachably connectable to hydraulic linkages such as hydraulic hoses and conduits (not shown) that are extendable from a front portion of the semi-trailer  100  for detachably connecting to a tractor-truck hydraulic power system typically powered by the engine of a tractor-truck vehicle having an adequate power output to tow the semi-trailer  100  over significant distances.  
      A hydraulic power and motor control mechanism of conventional design (not shown) is provided such as hand-operated lever controls in communication with the respective lifting cylinders, in order to provide operator control of the hydraulic pressure supplied to respective rear, front and middle hydraulic cylinders  154 ,  164 ,  180  thereby controlling the synchronous raising of the second sidewall  134  from the closed position  140 ′ to the open position  140  above the platform  116 . A lock-out electrical or mechanical control mechanism is provided as part of the hydraulic power and motor control mechanism to negate the raising of the second sidewall  134  while the semi-trailer  100  is being moved, and to negate the lowering of the second sidewall  134  during loading and unloading of the platform  116 . Upon elevation of the second sidewall  134  to the open position  140 , a plurality of vehicles  192 ,  192 ′,  192 ″, and/or other recyclable materials are readily loaded and stacked on the platform  116  by a forklift  190  (see  FIG. 2 ), or rolled and positioned onto the platform  116  from an adjacent loading ramp (not shown). When moved to the closed position  140 ′, the second sidewall  134  contains the stacked vehicles  192 ,  192 ′,  192 ″, and/or other recyclable materials for safe transport over roads in compliance with U.S. Department of Transportation regulations.  
      Rapid loading and stacking of salvageable vehicles onto the platform  116  is provided by a forklift  190  when the second sidewall  134  is elevated by the lifting mechanism  150  from the closed position  140 ′ to the open position  140  above the platform  116 . When a forklift  190  is not available for loading, a plurality of salvageable vehicles and/or compacted recyclable materials are readily lowered by an overhead crane (not shown) through either of the open tops  136 ′,  136 ″ and into the contained space bounded by the first sidewall  130 , the front end wall  122  having the upper front support segment  142  above, the closed second sidewall  134 , and the rear end wall  124  having the upper rear support segment  144  above. An additional benefit of the semi-trailer  100  having the second sidewall  134  mounted for clamshell movement is the option of loading additional recyclable materials along with a plurality of crushed vehicles  192 ,  192 ′,  192 ″ from the platform second side  116 ″ when the sidewall is raised  140 . Alternatively, If the trailer  100  is not filled to its preferred twenty ton load capacity, the second sidewall  134  can be positioned in the closed position  140 ′ and loading continued for any remaining unoccupied compartmental units  110 ,  110 ′ by lowering from overhead a plurality of various compacted and/or non-compacted recyclable materials through either of the open tops  136 ′,  136 ″.  
      Additional features of the platform  116  and multi-wheeled undercarriage  112  includes a support jacking device  118 ′ positioned underneath the front end  118 . The jacking device  118 ′ is temporarily extendable during stationary loading and unloading of the platform  116  in order to maintain a level platform. The front support jacking device  118 ′ is retractable under the front end  118  of the platform  116  during towed transport of the wheeled undercarriage  112  in a conventional manner. A trailer hitch  114  is disposed under the platform front end  118  (see  FIG. 6 ), or a similar coupling device is utilized as known to those skilled in the art regarding towed semi-trailers. The trailer hitch  114  is releasably connectable to a docking unit on a tractor-truck vehicle (not shown) for towing the semi-trailer  100  over public roads for loading and unloading at appropriate facilities of crushed vehicles and/or salvageable recyclable materials.  
      An additional embodiment for the second sidewall  134  and upper frame  136  includes a retractable canvas tarp or similar flexible synthetic cover that is extendable from an upper position above front support segment  142  to cover the length and width of the open tops  136 ′,  136 ″ to minimize loss of debris during transport of crushed vehicles and/or other scrap materials from within the semi-trailer  100 . Those skilled in the art will recognize that a semi-trailer  100  having one sidewall  134  mounted for clamshell movement can be utilized for transport of a plurality of salvageable materials and/or for transport of a plurality of large objects having recycle value and which require side-loading by a forklift  190  with the sidewall  134  in an elevated position  140 . A unique feature of the semi-trailer  100  having one sidewall  134  mounted for clamshell movement includes the option of loading materials from an overhead position into either of the open tops  136 ′,  136 ″ when the sidewall  134  is in a closed position  140 ′. Also, no chains or straps are required to retain the materials in the semi-trailer  100 . Rapid loading and unloading of materials is feasible whether the sidewall  134  is raised  140  or in the closed position  140 ′, and no manipulation of chains or straps is required as is typical of prior transport trucks. One skilled in the art will recognize that either sidewall is mountable for clamshell movement above the platform  116 . An additional embodiment includes a second side having a lower sidewall portion separate from an upwardly pivoting second sidewall. The second side lower sidewall can be hydraulicly pivotable along a base edge aligned with the platform second side  116 ″, for movement of the lower sidewall to an inclined position (not shown) and forming a ramp extendable to a loading dock or the ground from the second side  116 ″ to facilitate side access loading and unloading without departing from the spirit and scope of the present invention.  
      While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.