Abstract:
An apparatus for remotely locking and unlocking a door on a transportable container, the container sized and configured to ride atop a vehicle, includes latch means mountable to the container for locking shut and unlocking the container door relative the container, linkage means mountable to the container, connected with the latch means and being for actuating the latch means, and drive means mountable to the vehicle and being for driving the linkage means, the drive means being operable remotely by a driver of the vehicle.

Description:
This application is a continuation of application Ser. No. 08/659,560, filed Jun. 6, 1996, now abandoned, which is a continuation of Ser. No. 08/417,139 filed Apr. 4, 1995, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of transportable containers, and more specifically, to an apparatus and method for remotely locking and unlocking a container adapted for transport upon one or more vehicles. 
     BACKGROUND OF THE INVENTION 
     Containers for bulk materials and other products come in numerous sizes and load capacities. Such containers are typically transported from one site to another by a motor vehicle or by railroad. In some cases, however, it is desirable to transport the container a part of the overall distance by railroad and part of the way by motor vehicle. Some of the containers adapted for transport in this manner are configured to carry bulk materials such as coal, stone and the like, and they will be equipped with a rear dump door. When the driver of the vehicle carrying the container arrives at the dumping destination, it is desirable for the driver to be able to both unlock the dump door and pivot the tilt frame of the vehicle, all from a remote location, i.e. the truck cab. This requires an interface between the dumping container and the truck cab enabling activation of a mechanism within the cab to unlock a mechanism at container dump door. Such interface must not inhibit or complicate the transport of the container on the railroad car or on the motor vehicle, nor should such interface inhibit or complicate the container dumping process. The mechanism should resist accidental unlocking and should enable the dump door to be remotely locked, as well. It is also desirable for the vehicle and railroad car to be able to hold the transportable container firmly in position during transport without interfering with the remote locking and container dumping functions. 
     What is needed is a container and vehicle assembly which provides for remote locking and unlocking of a dump door of a transportable container without inhibiting or complicating the transport or dumping processes. 
     SUMMARY OF THE INVENTION 
     A mechanism is provided for use with transport vehicles and a container that may be transported and/or dumped by a number of different vehicles whereby a door of the container may be locked and unlocked remotely. 
     Generally speaking there is provided an apparatus for remotely locking and unlocking a door on a transportable container, the container sized and configured to ride atop a vehicle. The apparatus includes a latch means mountable to the container for locking shut and unlocking the container door relative the container, linkage means mountable to the container, connected with the latch means and being for actuating the latch means, and drive means mountable to the vehicle and being for driving the linkage means, the drive means being operable remotely by a driver of the vehicle. 
     It is an object of the present invention is to provide an improved mechanism for locking and unlocking a door on a transportable container. 
     A further object of the present invention is to provide an improved mechanism for locking and unlocking a door on a transportable container that permits the container to be freely moved from one vehicle to another for transport and/or dumping. 
     Another object of the present invention is provide an improved mechanism for locking and unlocking a door on a transportable container which has a mechanism urging the door to stay in the locked condition once placed in the locked condition. 
     Further objects and advantages of the present invention will become apparent from the following description of the preferred embodiment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side, elevational view of the apparatus for remotely locking and unlocking a door on a transportable container incorporated with a container and dump trailer in accordance with the present invention, and with the apparatus shown in the unlocked condition and the container dump door swung partially open. 
     FIG. 2 is a plan view of the tilt frame  14  of the dump trailer of FIG.  1 . 
     FIG. 3 is a perspective view of the forward left air-activated hold down assembly  23  of the tilt frame of FIG. 2 taken along the lines  4 — 4  and viewed in the direction of the arrows, and with the plug assembly  55  exploded away from the rest of assembly  23 . 
     FIG. 4 is a side, cross-sectional view of the air activated hold down assembly  23  of FIG. 3 taken along the lines  4 — 4  and viewed in the direction of the arrows, and with a portion of container  10  shown locked in a transport position atop tilt frame  14 . 
     FIG. 5 is a side, elevational and partially cross-sectional view of the hydraulic actuator assembly  41  of tilt frame  14  of FIG. 2, and with slide yoke  93  shown in the fully retracted locking condition against the bias of spring  125 . 
     FIG. 6 is a side, elevational view of the hydraulic actuator assembly  41  of FIG. 5 shown with slide yoke  93  in the extended and unlocking condition. 
     FIG  7  is an end cross-sectional view of the hydraulic actuator assembly  41  of FIG. 6 taken along the lines  7 — 7  and viewed in the direction of the arrows. 
     FIG. 8 is a bottom view of the rear of the container  10  of FIG. 1, and showing the linkage assembly  147  in the locking condition. 
     FIG. 9 is a side, elevational and partially cross-sectional view of the container  10  of FIG. 8 taken along the lines  9 — 9  and viewed in the direction of the arrows, and including hydraulic actuator assembly  41  operably juxtaposed therebelow with portions thereof broken away for clarity, and with latch mechanism  27  and linkage assembly  147  shown in the locked condition. 
     FIG. 10 is a side, elevational and partially cross-sectional view of the container  10  and actuator  41  of FIG. 9 showing linkage assembly  147  in the unlocked condition. 
     FIG. 11 is a top, partially cross-sectional view of latching mechanism  27  and a portion of container  10  of FIG. 9 taken along the lines  11 — 11  and viewed in the direction of the arrows. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, and alterations and modifications in the illustrated device, and further applications of the principles of the invention as illustrated therein are herein contemplated as would normally occur to one skilled in the art to which the invention relates. 
     Referring to FIG. 1, there is shown a transportable container  10  mounted atop a dump trailer  11  in accordance with the preferred embodiment of the present invention. Trailer  11  includes a trailer frame  12  and a tilt frame  14  pivotally mounted to frame  12  at rear hinges  15 . The trailer frame of FIG. 1 is of conventional form with a tandem axle wheeled suspension unit  18  at its rearward end and a gooseneck  16  at its forward end. The gooseneck is provided with the usual king pin  19  for connection to a tandem axle tractor (not shown). Tilt frame  14  includes a chute  22  and four air activated hold down assemblies  23 . Tilt frame  14  is pivoted about rear hinges  15  by a pair of hydraulic cylinders  24  (one shown) which are pivotally connected therebetween. A remotely operated locking mechanism  27  is shown in the unlocked position, thereby allowing a dump door  28  to pivot open as tilt frame  14  is pivoted about hinges  15 . 
     Referring to FIGS. 1 and 2, tilt frame  14  is constructed as a long, box-like weldement including a pair of laterally spaced, elongate sills  30  and  31  and a number of cross braces  32  which extend between and interconnect sills  30  and  31 . Also spanning across and welded to sills  30  and  31  are front and rear cross sills  33  and  34 . The outer ends  37  and  38  of cross sills  33  and  34 , respectively, extend outwardly of sills  30  and  31  and are structurally supported by angle braces  39  and  40 , as shown in FIG.  2 . Four air activated hold down assemblies  23  are mounted, one each to the outer ends  37  and  38  of cross sills  33  and  34 . A hydraulic actuator assembly  41  is rigidly mounted centrally to tilt frame  14  by two pair of mounting braces  42 . Actuator assembly  41  also includes a double acting hydraulic cylinder  44  which is anchored at  45  to one of the cross braces  32 . Tilt frame  14  further includes a front mounted container stop and guide member  46  that assists in aligning container  10  as it is lowered onto tilt frame  14 . A rear cross sill  47  is rigidly connected to and extends across and outwardly of sills  30  and  31 . As it is desirable to evenly distribute the weight of container  10  and its load equally between the trailer&#39;s and truck&#39;s wheel assemblies, container  10  is positioned somewhat forwardly of its rear  48 . A chute  22  is therefore provided to guide the flow of bulk material as it exits the rear of container  10 . Chute  22  is supported by and mounted to rear cross sill  47  and sills  30  and  31 . As shown in FIG.  1  and in phantom in FIG. 2, chute  22  is made wide enough to permit dump door  28  to pivot outwardly from container  10  and permit the free flow of bulk materials exiting container  10  to the rear of trailer  12 . 
     Referring to FIGS. 2-4, there is shown the hold down assembly  23  that is mounted to the left outer end  37  of front cross sill  33 . Hold down assembly  23  is shown exploded in FIG.  3  and is shown in a substantially locked condition in FIG.  4 . Hold down assembly  23  includes a double acting air cylinder  51 , a side guide plate  52 , a front guide plate  53 , a container locator  54  and a plug assembly  55 . Plug assembly  55  includes a formed wall  56  and a pair of opposing side wall sections  57  extending orthogonally inwardly from opposing edges of formed wall  56 . A rectangular cross-sectioned slide tube  61  extends inwardly from formed wall  56 . A circular cross-sectioned locking plug  62  also extends inwardly from formed wall  56  above and slightly rearwardly relative to slide tube  61 . 
     Cross sill  33  is hollow and defines a rectangular opening  58  at the outside of outer end  37 . Side and front guide plates  52  and  53 , respectively, are rigidly fixed to the outer side and front side of outer end  37 , as shown in FIG.  3 . Side plate  52  defines a substantially rectangular opening  63  which aligns with opening  58 . Openings  58  and  63  and slide tube  61  are complementarily dimensioned to allow slide tube  61  to be received through openings  58  and  63  and into the hollow cavity  64  of cross sill  33 , as shown in FIG.  4 . Side plate  52  also defines a hole  65  above and slightly rearwardly of opening  58 . Hole  65  is sized and aligned to receive plug  62  while openings  58  and  63  receive slide tube  61  into cavity  64  as shown. The leading ends of both slide tube  61  and locking plug  62  are chamfered at  66  and  67 , respectively, to facilitate their entry into hole  65  and openings  58  and  63 . Double acting air cylinder  51  is fixedly mounted to formed wall  56  just below cross sill  33  by four rectangularly spaced bolts  68  (two shown in FIG.  4 ). The piston  71  of air cylinder  51  is connected on one side to a rod  72 . A spring  73  extends in tension between rod  72  and anchor clip  74 , clip  74  being rigidly mounted to the underside of cross sill  33 . A bolt  75  extends through an opening  76  in formed wall  56  and connects to the other side of piston  71  of air cylinder  51 . Spring  73  acts to pull rod  72 , piston  71 , bolt  75  and thereby plug assembly  55  inwardly to a locked condition whereby plug  62  extends through hole  65  and into a cast corner block  77  of a container  10  seated thereabove. Activation of air cylinder  51  moves piston  71  outwardly which, against the bias of spring  73 , moves plug assembly  55  to its outer and unlocked condition (shown in phantom at  78 ) whereby locking plug  62  is withdrawn from corner block  77 . For clarity, plug assembly  55  is shown in FIG. 4 in substantially the locked condition. Plug assembly  55  may yet be activated a small distance to the right into the locked condition. Plug assembly  55  is provided with a set of four holes  79  which align with and provide clearance and access for the heads of bolts  68 . The top of side guide plate  52  is angled outwardly at  80  to provide a guide for lowering container  10  down into its seated transport and dumping position (shown in FIGS.  1  and  4 ). A U-shaped housing  81  is fixed to the underside of cross sill  33  and protects air cylinder  51 . 
     Outer end  37  of cross sill  33  defines a top surface  82  upon which rests container  10  at its corner block  77 . Fixedly connected to and extending upwardly from surface  82  is container locator  54 . Locator  54  has a large dimensioned arcuate nub portion  85  which lies substantially in a longitudinal plane, and has a small dimensioned arcuate nub portion  86  lying substantially orthogonal to nub portion  85 . Each container  10  adapted for transport and dumping by trailer  11  includes a cast corner block  77  at each of its bottom four corners. (Hold down assemblies  23  are each substantially the same and the description herein of assembly  23  at the front left corner of tilt frame  14  is representative thereof. One notable exception, however, is that the hold-down assemblies  23  at the rear of tilt frame  14  (on outer ends  38  of cross sill  34 ) have rear guide plates  89  instead of front guide plates  53 , again to help guide a container  10  down to the correct transport and dumping position on tilt frame  14 .) Each block  77  includes at least side and bottom openings  87  and  88 , respectively. Bottom opening  88  is sized to receive container locator  54  therein to restrain container  10  to no or a minimal amount of lateral and longitudinal movement while riding atop trailer  11 . Likewise, side opening  87  is sized and configured as desired to receive locking plug  62  therein to restrain container  10  from any or minimal vertical movement. The arcuate sections of nub portions  85  and  86  facilitate guiding container  10  into position. In the event of failure of any of air cylinders  51  to hold plug assembly in a retracted locked condition, spring  73  biases plug assembly into the locked condition. 
     Referring now to FIGS.  2  and  5 - 7 , hydraulic actuator assembly  41  comprises a guide channel  90 , a slide yoke  93  and a double acting hydraulic cylinder  94 . Guide channel  90  is comprised of a pair of C-beams  91  and  92  which are mirror images of each other. C-beam  91  has a vertical wall  95  and bottom and top walls  96  and  97 . The lower surface of top wall  97  and the upper surface of bottom wall  96  are slanted at  98  as shown. C-beams  91  and  92  are rigidly connected with each other by bottom cross plates  100  and  101  and by end plate  102 . End plate  102  defines a centrally located hole  103 . 
     Slide yoke  93  includes a pair of identically shaped, parallel yoke frame members  106  and  107 . Frame members  106  and  107  are formed plates which are rigidly held in a parallel relationship by fore and aft rectangular cross sectioned spacer tubes  108  and  109 . Each frame member  106  and  107  also defines upwardly extending, fore and aft stanchions  110  and  111 . Fore stanchion  110  of frame members  106  and  107  each define a rearwardly facing edge  114  that forms an angle with vertical of approximately 20°, as shown in FIG. 5. A generally rectangular shaped wear plate  115  is fixed to and across edges  114  of fore stanchions  110  of members  106  and  107  by conventional means, such as screws (not shown). Likewise, aft stanchions  111  of members  106  and  107  each define a forwardly facing edge  116  that also forms an angle with vertical of approximately 20°. A generally rectangular wear plate  117  is fixedly mounted to and across edges  116  by appropriate means such as screws (not shown). Wear plates  115  and  117  may be made of any appropriate durable material, such as steel. As shown in FIG. 5, both wear plates  115  and  117  slope upwardly rearwardly at an angle of approximately 20° with the vertical. 
     On the outside of each yoke frame member  106  and  107  are mounted a pair of spacers  118 , and to the outside of each pair of spacers  118  are mounted a pair of wear strips  119 . Spacers  118  and wear strips  119  are mounted to their respective frame members  106  and  107  by appropriate means such as screws  120 . Wear strips  119  are sized to fit snugly within the angled inner surfaces  98  of bottom and top walls  96  and  97  of C-beams  91  and  92 . Slide yoke  93  is thus permitted to slide forward and rearward in reciprocating fashion within guide channel  90 . 
     Slide yoke  93  further includes a yoke positioning rod  123 . Rod  123  is mounted to fore spacer tube  108  and extends therefrom through aft spacer tube  109  and extends therefrom rearwardly through hole  103  of end plate  102 . Rod  123  is welded to both fore and aft spacer tubes  108  and  109  for rigid support. The outboard end  124  of rod  123  is fitted with a compression spring  125 . A nut  126  or other appropriate stop means is firmly connected to the outer most end  127  of rod  123  to prevent spring  125  from moving off the end  127  of rod  123 . 
     Double acting hydraulic cylinder  94  is anchored at one end  130  to a cross brace  32  (FIG.  2 ). The outboard end of the piston rod  131  of cylinder  94  is mounted to yoke frame members  106  and  107  by appropriate means such as a pin  132 . Guide channel  90  is then firmly held in place by four mounting braces  42  that are welded to the outsides of guide channel  90  at their inner ends and to sills  30  and  31  at their outer ends, as shown in FIG.  2 . Also, plates  100  and  101  extend outwardly of guide channel  90  to be mounted for additional support to the undersides of mounting braces  42  (FIG.  2 ). A hole  133  is provided in cross sill  34  to permit the reciprocating movement of yoke positioning rod  123  therethrough. 
     FIG. 5 shows hydraulic cylinder  94  completely retracted which pulls slide yoke  93  to its rear most position and against the bias of compression spring  125 . The hydraulic circuit (not shown) connected with hydraulic cylinder  94  is configured so that upon release of the switch, lever or the like that activates the cylinder  94 , cylinder  94  will be vented. As will be described herein, compression spring  125  will then pull slide yoke  93  several inches to the rear (to the left as shown in FIG.  5 ). In the extended position shown in FIG. 6, cylinder  94  has been activated to extend slide yoke  93  toward the rear of the trailer. In this case, yoke positioning rod  123  and its spring  125  offer no resistance to the movement of slide yoke  93 . 
     Referring now to FIGS. 1,  8 - 11 , transportable container  10  generally includes a welded skeleton of rectangular cross-sectioned tubing with steel panels welded thereto. Door  28  is mounted at the rear of container  10  by hinges (not shown) at the top edge thereof to permit the door to swing rearwardly open as shown in FIG.  1 . Included in the container skeleton are lower, longitudinal rectangular cross-sectioned tubing members  136  and  137 . Extending between members  136  and  137  is a C-beam  138  and additional rectangular cross-section tubing members  139  and  140 . Extending longitudinally between beams  138  and  140  are four linkage assembly mounting beams  143 - 146 . Container  10  further includes latching mechanism  27  and linkage assembly  147 . Latching mechanism  27  will now be described. 
     Latching mechanism  27  includes two pairs of latch assemblies  150 , one pair on each side of container  10 . In each pair, there is an upper latch assembly and a lower latch assembly, the two being interconnected and driven by a vertical link  151 . Each latch assembly  150  includes a latch  152 , a pair of latch side plates  153  and  154  and a pair of bell cranks  155  and  156 . Side plates  153  and  154  extend in parallel through an opening  157  in, and are fixed as by welding to, vertical frame member  159  of container  10 . Latch  152  is shaped as shown in FIG.  9  and extends between side plates  153  and  154 . The outboard end  160  of latch  152  is curved upwardly into a hook to engage with a corresponding, outwardly extending pin  161  of door  28 . Latch  152  further defines an arcuate slot  162  through which extends a follower pin  163 , pin  163  being held by and between side plates  153  and  154 . The inboard end  164  of latch  152  is pivotally connected between and to the top corners of triangular shaped bell cranks  155  and  156  by appropriate means such as bolt  167 . The bottom, rearward corners of bell cranks  155  and  156  are connected to the outside of side plates  153  and  154  by appropriate means such as bolt  168 , as shown. The forward bottom corners of bell cranks  155  and  156  are pivotally connected to and on opposing sides of a flange  169  by appropriate means such as bolt  170 , as shown. Flange  169  is rigidly connected with vertical link  151 . An offset platform  171  is connected to the bottom of vertical link  151  and extends inwardly thereof. A gusset  172  is connected between vertical link  151  and offset platform  171  to provide additional support therebetween. A mounting flange  173  extends downwardly from offset platform  171  to provide connection with linkage assembly  147 . 
     Referring now to FIGS. 1, and  8 - 10 , linkage assembly  147  comprises a number of pivotally mounted links and levers which translate the sliding action of hydraulic actuator assembly  41  to drive latch mechanisms  27  and which provide biasing means for urging latch mechanism  27  to remain in a locked condition once placed in a locked condition and in the unlocked position once placed in the unlocked condition. Generally, linkage assembly  147  includes mounting shafts  176  and  177 - 180 , outer levers  181 , intermediate lever pairs  182  and  183 , inner levers  184 , locking links  185 , springs  186  and roller  187 . Mounting shaft  176  extends between and is held for rotation by tubing members  136  and  137 . Outer levers  181  are fixed to rotate with shaft  176  at the outer ends of shafts  176 . A connecting link  189  is pivotally mounted to each of the outer levers  181 , extending upwardly therefrom to a pivotal mounting to flange  173 . Linkage assembly  147  is identical on either side of roller  187  and the following description will be directed to one side only. Further, FIGS. 9 and 10 show the various elements of linkage assembly  147  with linkage assembly mounting beams  145  and  146  removed for clarity. 
     Also fixedly mounted to rotate as a unit with shaft  176  and outer lever  181  is the pair of levers  182 . One end of locking link  185  is pivotally mounted between and at the outboard ends of links  182  by a pin  190 . The other end of locking link  185  is pivotally mounted between and at the outboard ends of links  183  by appropriate means such as a pica  191 . The inboard ends of links  183  are fixedly mounted to separate but coaxial shafts  177  and  178  to rotate as a unit therewith, as shown. Shaft  177  is held for rotation about its axis by mounting beam  146 . Shaft  178  is likewise held for rotation about its axis by mounting beam  145 . Shaft  178  extends through beam  145  toward beam  144  where it is rigidly connected to the inboard end of inner lever  184  to rotate as a unit therewith. Roller  187  is mounted between and at the outboard ends of inner levers  184 . Roller  187  is mounted to freely pivot about its axis, but other configurations are contemplated where roller  187  would comprise or include a wear ring or other structure which would enable it not to rotate, but to withstand rubbing action of an input as will be described herein. A spring clip  192  is fixed to locking link  185  at the forward end  194  thereof where locking link  185  connects with pin  191 . Spring  186  extends in tension between spring clip  192  and an anchor ring  193 , ring  193  loosely encircling mounting shaft  176 . 
     In operation, and with linkage mechanism  147  and latch mechanism  27  in the locked condition shown in FIG. 9, hydraulic actuator assembly  41  is remotely activated by the vehicle operator which drives slide yoke  93  rearwardly (to the left in FIG.  9 ). Wear plate  115  contacts roller  187  and urges it rearwardly which rotates inner levers  184  which also rotates shafts  178  and intermediate levers  183  about the common axis  195  of shafts  178  and  177  (clockwise as shown in FIG.  9 ). Clockwise rotation of intermediate levers  183  drives end  194  and spring  186  downward through and past axis  195 . Further rotation of lever  183  due to rearward movement of slide yoke  93  drives locking links  185  rearwardly which rotates intermediate levers  182 , shaft  176  and outer levers  181  clockwise as shown in FIG.  9 . This drives connecting link  189  and vertical link  151  upwardly which rotates bell cranks  156  about bolts  168  which translates latches  152  along follower pins  163 , thereby moving latches  152  from the locked condition (shown in solid lines in FIG. 9) to the unlocked condition (shown in phantom in FIG.  9  and shown in FIG.  1 ). The resulting position of linkage assembly  147  and slide yoke  93  in the unlocked condition is shown in FIG.  10 . The tension of springs  186  continues to urge locking links  185  rearwardly toward the unlocked condition and thereby biases latching mechanism  27  and linkage mechanisms  147  in the unlocked condition. 
     From the unlocked condition shown in FIGS. 1 and 10, activation by the vehicle operator of hydraulic actuator assembly  41  in the opposite direction retracts slide yoke  93  (to the right in FIG. 10) whereupon wear plate  117  contacts roller  187  and pivots levers  184  and  183  counterclockwise (FIG. 10) about axis  195  which translates locking link  185  which rotates levers  182  and  181  and shaft  176  counterclockwise (FIG. 10) which draws connecting link  189  and vertical link  151  downwardly which rotates bell cranks  155  and  156  about bolts  168  and pulls latches  152  along follower pins  163  into the locking condition shown in FIG.  9 . Complete retraction of slide yoke  93  by cylinder  94  rotates intermediate links  183  enough to move the as of spring  186  above axis  195  at which point spring  186  continues to urge counterclockwise rotation of lever  183  about shafts  177  and  178 , that is, to stay in the locked condition. 
     Upon complete retraction of slide yoke  93  by cylinder  94 , the forward end  197  of compression spring  125  (FIGS. 5 and 6) engages with end plate  102  and spring  125  is compressed, its length being shortened by several inches. After the activating mechanism for cylinder  94  is released, venting cylinder  94 , spring  127  will pull slide yoke  93  rearwardly several inches (shown in phantom at  198 , FIG.  9 ). This will put slide yoke  93  into a neutral position wherein a container  10  may be unloaded and loaded and roller  187 , during positionment of container  10  onto tilt frame  14 , will not engage with wear plate  117  and inadvertently unlock door  28 . 
     A hex nut  196  is provided at the outer ends of both shafts  177 . This allows linkage assembly  147  to be manually locked or unlocked, if desired. Container  10  also is provided with a cast corner block  200  at each of its top four corners so that containers  10  may be stacked atop one another. 
     One intended use of the present invention is to provide transportation for containers  10  containing bulk materials such as coal by railway from the source to a transfer point where container  10  is moved from a railway car to a dump trailer of the type shown in FIG.  1 . The semi-trailer rig may then be driven a shorter distance to its destination at which point the driver can remotely unlock the dump door  28  and dump the load without leaving the vehicle cab. Other embodiments are also contemplated wherein the present invention will enable the container  10  to be transported by two different semi-trailers. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.