Abstract:
An apparatus for the loading and unloading of railroad boxcars includes a first platform assembly that abuts the boxcar and a second platform assembly that abuts the first platform assembly and is secured thereto. The height of the first platform assembly is adjustable proximate the boxcar. The height of the second platform corresponds to that of a tractor-trailer&#39;s floor. A ramp allows a forklift to drive up onto and down off of the two platforms. Safety rails prevent the forklift from driving off of any raised portion of the apparatus. A trailer intermediate plate allows the forklift to pass onto the floor of the tractor-trailer and an intermediate plate allows the forklift to pass onto the floor of the boxcar. The apparatus includes three main component parts (the first and the second platform and the ramp) that are each adapted for lifting and movement by the forklift. The apparatus is portable for temporary use where desired, can be disassembled, moved, and used elsewhere.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention, in general relates to railroads and, more particularly, to unloading railroad cars. 
   It is necessary to unload cargo from railroad boxcars and transfer the contents to trucks, such as tractor-trailer trucks, also known as “eighteen wheel” trucks, and other similar vehicles. 
   To handle the weight, concrete docks, also known generally as “cross-docks” are used. The cross-dock allows unloading of the railroad box cars by forklift at one side and transfer of the cargo to a truck trailer at another side. It is necessary for the dock to bear the weight of the forklift plus cargo. Therefore, it has to be strong. Concrete is the only known viable prior-art way of building a cross-dock. 
   Sometimes, the need for unloading boxcars is temporary or intermittent. In such instances there is no need for a permanent installation of a cross-dock. However, there has been no previously known way of providing a portable cross-dock system that is both structurally sound and which can be effectively moved from place to place. 
   Also, for certain work areas it is not permissible to build and permanently leave a cross-dock system in place. Sometimes, because of the needs of the project at hand, the cross-dock must be built at substantial cost, used for a period of time, and then torn down and destroyed after it has served its purpose. The debris must then be hauled away, also at significant expense. 
   Accordingly, there exists today a need for a portable cross-dock system that helps to ameliorate the above-mentioned difficulties and also those that are briefly mentioned in the objects, hereinafter. 
   Clearly, such a system would be especially useful and desirable. 
   2. Description of Prior Art 
   Concrete cross-docks are, in general, known. While the structural arrangements of the above described devices may, at first appearance, have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices. 
   OBJECTS AND SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a portable cross-dock system that can be assembled in situ. 
   It is also an important object of the invention to provide a portable cross-dock system that can be assembled in a desired position, used, and then disassembled and removed. 
   Another object of the invention is to provide a portable cross-dock system that can be assembled in a desired position, used, disassembled, moved to a new location, and then reassembled and reused at the new location. 
   Still another object of the invention is to provide a portable cross-dock system that is economical to use. 
   Still yet another object of the invention is to provide a portable cross-dock system that can be disassembled into component parts that can each be transported by forklift. 
   Yet another important object of the invention is to provide a portable cross-dock system that is safe to use. 
   Still yet another important object of the invention is to provide a portable cross-dock system that can support the weight of a forklift and a cargo. 
   A first continuing object of the invention is to provide a portable cross-dock system that permits forklift access to boxcars having various floor-heights. 
   A second continuing object of the invention is to provide a portable cross-dock system that can accommodate different rail types. 
   A third continuing object of the invention is to provide a portable cross-dock system that can accommodate different boxcar types. 
   A fourth continuing object of the invention is to provide a portable cross-dock system that permits loading of cargo from a boxcar into a trailer that is disposed on an opposite side of the cross-dock system as compared to that of the boxcar. 
   A fifth continuing object of the invention is to provide a portable cross-dock system that permits loading of cargo from a boxcar into a trailer that is disposed on an adjacent side of the cross-dock system as compared to that of the boxcar. 
   A sixth continuing object of the invention is to provide a portable cross-dock system that includes a ramp. 
   A seventh continuing object of the invention is to provide a portable cross-dock system that includes a ramp that can be located where desired. 
   An eighth continuing object of the invention is to provide a portable cross-dock system that includes safety rails to prevent a forklift from accidentally driving off of a platform of the cross-dock. 
   A ninth continuing object of the invention is to provide a portable cross-dock system that includes means for interconnecting a pair of platforms together. 
   A tenth continuing object of the invention is to provide a portable cross-dock system that permits the simultaneous loading of two truck trailers from the cross-dock system. 
   An eleventh continuing object of the invention is to provide a portable cross-dock system that is economical to manufacture. 
   A twelfth continuing object of the invention is to provide a portable cross-dock system that is economical to use. 
   A thirteenth continuing object of the invention is to provide a portable cross-dock system that is more economical to use at a particular location for a period of time, disassemble, transport, and use elsewhere at a second location than it would be to construct and maintain two or more separate fixed-in-position types of cross-docks at each separate location. 
   A fourteenth continuing object of the invention is to provide a portable cross-dock system that is sufficiently strong, locks together, is safe, and which does not contain any component part that exceeds a predetermined maximum weight. 
   A fifteenth continuing object of the invention is to provide a portable cross-dock system that is sufficiently strong, locks together, is safe, and which does not contain any component part that exceeds four-thousand pounds in weight. 
   A sixteenth continuing object of the invention is to provide a portable cross-dock system that includes members for a forklift to lift a platform at a balance point. 
   A seventeenth continuing object of the invention is to provide a portable cross-dock system that includes members that do not exceed a predetermined maximum length. 
   An eighteenth continuing object of the invention is to provide a portable cross-dock system that includes a plurality of adjustable length (height) legs on one side of a platform of the cross-dock system. 
   Briefly, a portable cross-dock system that is constructed in accordance with the principles of the present invention has a pair of platforms that are eight feet wide by sixteen feet long that are joined together at the longer dimension. An eight foot by twenty foot ramp allows forklift access up to the platforms. A support system provides load distribution for the platforms. Truck access is provided on one side of the platforms and railroad boxcar access is provided on another side. An adjustable height is provided to the platform at the boxcar access area to accommodate different height boxcars. Safety rails prevent the forklift from accidentally driving off of the platforms. Other elements are described hereinafter in the detailed description of a preferred embodiment thereof. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is top plan view of a portable cross-dock system. 
       FIG. 2  is a view in perspective the cross-dock system of  FIG. 1  with a ramp disposed on an opposite side thereof. 
       FIG. 3  is a top plan view of a second platform and is also applicable for the ramp of the cross-dock system of  FIG. 1 . 
       FIG. 4  is a rear elevation view of the second platform. 
       FIG. 5  is a side view of the cross-dock system of  FIG. 2 , absent the safety rails, taken along the line  5 - 5  therein. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring on occasion to all of the drawing figures and now, in particular, to  FIG. 1  and  FIG. 2  is shown, a portable cross-dock system, identified in general by the reference numeral  10 . 
   The cross-dock system  10  shows a first truck trailer  12  and a second truck trailer  14  being simultaneously loaded with cargo  16  that is being removed from inside of a boxcar  18  by a forklift  20 . The boxcar  18  is on a train track (rails)  19 . A first platform  22  is disposed adjacent the boxcar  18  (a few inches away) and a second platform  24  is disposed adjacent the two trailers  12 ,  14 . The first platform  22  and the second platform  24  are connected together along a longer dimension thereof, as is described in greater detail hereinafter. 
   A ramp  26  extends from an upper surface of the second platform  24  to the ground and is used for access by the forklift  20  and by foot traffic, as well. 
   Because the height of the train track  19  rails above the ground is a variable, as is the height of the floor of the boxcar  18  with respect to the bottom of its wheels (i.e., its height above the top of the track  19 ) a boxcar side  22   a  of the first platform that is in contact with the boxcar  18  must be of adjustable height (unless only a known type of boxcar  18  is used) with respect to the ground surface. Refrigerated boxcars  18  tend to have a higher floor height than other types. Ideally, the boxcar side  22   a  can vary from 42-46 inches. 
   A set of three jacks  28 ,  30 ,  32  are attached (welded or bolted) to a structural beam member  34 . The jacks  28 ,  30 ,  32  are adjusted in height by a crank  36  on either side and by a crank rod  38  that interconnects all of the jacks  28 ,  30 ,  32 . The jacks  28 ,  30 ,  32  are similar or identical to those commonly used on the fronts of the trailers  12 ,  14  and are well known for supporting the front of the trailers  12 ,  14  when they are separated from a truck  40 . The jacks  28 ,  30 ,  32  are permanently attached to the beam member  34  and include bottom plates  42  that help distribute the load onto the surface. 
   In use, the surface of the ground it prepared to receive the weight of the cross-dock system  10 . Preparation can vary greatly, depending on the nature of the surface. If the surface is a type of soil or other material that is well suited to bear the weight, little preparation other than grading is required. If the soil has a compaction rate that is not sufficient, small concrete footings (not shown) may be provided for use under each of the bottom plates  42  and for any other load bearing portions of the cross-dock system  10 . 
   The crank  36  on either side is rotated until the boxcar side  22   a  of the first platform  22  is at the same height as the floor inside of the boxcar  18 . When the crank  36  is rotated, all three jacks  28 ,  30 ,  32  change their height simultaneously, thereby uniformly raising or lowering the boxcar side  22   a.    
   There is a minimum effective combined size for the two platforms  22 ,  24  to permit adequate movement by the forklift  20 . However, it is desirable that the disassembled weight of any component part of the cross-dock system not exceed four-thousand pounds, to permit use of the forklift  20  for its loading for transport. Still, the cross-dock system  10 , when assembled, must support the weight of the cargo and of the forklift  20 . Those benefiting from this disclosure will, of course, be able to modify details of construction. 
   The overall width as shown by arrow  44  of each of the platforms  22 ,  24  is eight feet and the overall length as shown by arrow  46  is sixteen feet. The perimeter of each includes two end beams  48 ,  50  and two longitudinal beams  52 ,  54  that are welded together. A center longitudinal beam  56  is parallel to the longitudinal beams  52 ,  54  and extends between the two end beams  48 ,  50  and is welded thereto. Fourteen shorter spaced-apart interconnecting beams  58  (seven on each side of the center longitudinal beam  56 ) are attached and provide support for a grating  60  that is disposed thereon and attached (i.e., welded as desired). All of the beams  48 - 58  are preferably I-beams of sufficient size and strength. 
   Different types of grating  60  can be used and include non-porous (solid) planar sheets such as “diamond plate” to more open types having serrated surfaces and openings there-through. For example, if snow or ice is anticipated a more open type of grating  60  is preferred. 
   A two-inch diameter schedule-40 steel tubing is preferred for a plurality of safety rails  62 . The safety rails  62  are of any preferred length and are detachably-attachable with respect to the platforms  22 ,  24 . The safety rails each include a pair of vertical members  62   a  that are adapted to extend through holes  64  provided in a surface of the first platform  22  and the second platform  24 . The vertical members  62   a  each enter into one of a plurality o of sockets  66  that are disposed under the holes  64 . The sockets  66  are attached along the perimeter longitudinal beams  52 ,  54  and the end beams  48 ,  50 , except where access to the boxcar  18  at the boxcar side  22   a  is desired. 
   Cross-bracing  61  is used as desired between fixed support members  68  and the longitudinal beams  52 ,  54  or end beams  48 ,  50 . Load distributing plates  70  are disposed at the bottom of the fixed support members  68 . The load distributing plates  70  are placed on suitable soil or on footings that are provided at the site. 
   The primary difference between the first platform  22  and the second platform  24  is that the first platform  22  includes three of the jacks  28 ,  30 ,  32  on the boxcar side  22   a  instead of three more of the fixed support members  68  to permit varying its height. 
   The height of the second platform  24  is preferably fixed at or near 51 inches above the ground surface to accommodate the usual floor height of the tractor trailers  12 ,  14 . If desired, three more of the jacks  28 ,  30 ,  32  could be used to make the height of a trailer side  71  of the cross-dock system  10  adjustable. 
   Referring again primarily to  FIG. 3  and also to  FIG. 2 , the ramp  26  is similar in construction to the second platform  24  except that it includes a pair of fixed upper supports  72  (one shown) that are angled to match the tilt of the a pair of spaced apart modified longitudinal beams  74  (one shown). 
   A pair of fixed intermediate supports  76  (one shown) provide support for the center area of the modified longitudinal beams  74 . The modified longitudinal beams  74  include a tapered end  78  at an end opposite where the fixed upper supports  72  are disposed. The tapered end  78  allows a twelve inch extension skit plate  80  (dashed lines in  FIG. 3 ) to be disposed on the ground surface to allow easy access by the forklift  20 . 
   The ramp  26  can simply be placed as a free-standing unit that abuts either the first platform  22  or the second platform  24  where preferred. If desired, the ramp  26  can include an attachment plate  82  that is attached to the ramp  26  and extends there-from over the second (or first) platform  24 . Pins  84  can be used that pass through holes in the attachment plate  82  and secure it to the second platform  24 . 
   Ramp safety rails  86  can be detachable (as was previously described for the safety rails  62 ) or permanently attached to the sides of the ramp  26 , as desired. The ramp safety rails  86  and the safety rails  62  provide a raised perimeter obstruction that prevents the forklift  20  from accidentally driving off any elevated portion of the cross-dock system  10  and causing possible damage to the forklift  20  or possibly injury or even death to its operator. 
   An intermediate plate  88  is attached to the boxcar side  22   a  of the first platform  22 , and is preferably hingedly attached thereto. The intermediate plate  88 , along with the entire boxcar side  22   a , are lowered so that a first side  88   a  of the intermediate plate  88  is disposed on the floor of the boxcar  18  and an opposite second side  88   b  is or remains disposed on the first platform  22 . 
   A trailer intermediate plate  90  is preferably detachably-attachable to the second platform  24  where desired, at a location that does not include the safety rails  62 . The trailer intermediate plate  90  may include protrusions that extend into the holes  64  and secure it where desired along the perimeter of the cross-dock system  10 . 
   Accordingly, any of the safety rails  62  of the second platform  24  can be removed where desired and the trailer intermediate plate  90  can be used to provide a smooth planar transition surface to load the cargo  16  into the trailers  12 ,  14 . 
   Because access to the cross-dock system  10  by the trailers  12 ,  14  may be limited due to a lack of clearance or other obstructions, it is important to allow loading of the trailers  12 ,  14  wherever along the perimeter of the cross-dock system  10  is deemed to be convenient. Certain locations where the cross-dock system  10  is used may have ample room for maneuvering the trailers  12 ,  14  whereas other locations may be far more limited. 
   Versatility as to where the trailers  12 ,  14  are loaded is essential to providing a high-degree of portability for the cross-dock system  10 . The trailers  12 ,  14  can abut the second platform  24  on any of three sides or the first platform  22  on either of two opposite sides. Variability as to the location of the ramp  26  also provides a valuable benefit in that it permits selection of the preferred location(s) for loading the trailer(s)  12 ,  14  and then the ramp  26  is placed at whatever location remains. 
   Having versatility in this regard provides another unexpected benefit in that it also permits the simultaneous use of a plurality of the trailer intermediate plates  90 . This, in turn, allows for the simultaneously loading of a plurality of the trailers  12 ,  14 , thereby shortening the time required to unload the boxcar  18  and providing an increase in throughput. 
   It is important to secure the first and second platforms  22 ,  24  together. A variety of possible ways of doing so includes the use of the safety rails  62  so that one end of a safety rail  62  extend across and engage with holes  64  and sockets  66  in each of the platforms  22 ,  24 . Other interconnecting pins can be designed for this purpose, as well. 
   Referring now to  FIG. 5 , a preferred way of securing the first and second platforms  22 ,  24  so that they are adjacent each other along a inside side  22   b ,  24   b  of each includes the use of attachment members  92  to be welded (attached) in pairs where desired to an underside of the platforms  22 ,  24 . One of each pair of the attachment members  92  is attached proximate the inside side  22   b  of the first platform and the other is attached proximate the inside side  24   b  of the second platform  24  so that they are in alignment with each other. 
   A preferred type of a “come-along”  94  is secured at opposite ends thereof to one of the pair of attachment members  92  and is used to urge the two inside sides  22   b ,  24   b  closer together until they are disposed tightly against each other. 
   A preferred type of the come-along  94  includes a lever  96  and threaded members that, when the lever  96  is urged back and forth, draw the opposite ends together as well as the two platforms  22 ,  24 . 
   It is important for the forklift  20  to be able to safely raise and move each platform  22 ,  24  which are the larger and heavier component parts of the cross-dock system  10 . 
   If an unskilled forklift  20  operator (not shown) were to pick up these heavier component parts in the wrong way, for example way out of balance, there is danger that they could create an imbalance and possibly fall off of the forklift  20 . 
   A pair of forklift members  98 ,  100  ( FIG. 4 ) are preferably attached to each platform  22 ,  24  at a balance point. The forklift members  98 ,  100  include rectangular stock of a predetermined length that is selected to allow the “forks” of the forklift  20  to enter therein. The forklift members  98 ,  100  are welded or otherwise suitably attached to the platforms  22 ,  24 . 
   Once engaged by the forks of the forklift  20 , each of the platforms  22 ,  24  can be lifted by the forklift (one at a time) and transported where desired, typically unto the bed of a flat bed trailer (not shown) for transport of the cross-dock system  10  to another location. 
   To assemble cross-dock system  10  for use, the first platform  22  is placed by the forklift  20  adjacent the track  19 . The second platform  24  is placed as close as possible to the first platform  22  so that the inside sides  22   b ,  24   b  of each are parallel and close together. A plurality (preferably two or three) of the come-alongs  94  are opened a sufficient amount and the opposite ends of each are attached to a pair of the attachment members  92 . Each come-along  94  is then tightened a small amount and the process is repeated until the two platforms  22 ,  24  are held tightly together. 
   A sufficient quantity of the safety rails  62  are attached where required. One of the trailer intermediate plates  90  is attached wherever the safety rails  62  have been omitted and a gap in railing occurs. This is wherever a rear of one of the trailers  12 ,  14  is to be disposed. 
   The ramp  26  is transported by the forklift  20  and placed so that an upper portion of the ramp  26  is disposed adjacent to the first platform  22  or the second platform  24 , where desired. The ramp  26  preferably also includes a modified pair of the forklift members  102  ( FIG. 2 ) at a balance point. The modified forklift members  102  include openings of sufficient size to permit the forks of the forklift  20  to enter into them, even when the ramp  26  is disposed at an angle. The ramp  26  is secured to the first or second platform ( 22 ,  24 ) as desired. 
   After arrival of the boxcar  18  and the trailers  12 ,  14 , the intermediate plate  88  is attached to the first platform  22  (if it is detachable) so that it engages with the floor of the boxcar  18 . The trailer intermediate plate(s) are also attached where needed. 
   The forklift  20  drives up the ramp  26 , onto the second platform  24  (or the first platform  22 ), across and over the intermediate plate  88  and into the boxcar  18 . The cargo  16  is lifted by the forks and transported out of the boxcar  18 , unto the first platform  22 , onto the second platform  24 , and over the trailer intermediate plate  90  and into one of the trailers  12 ,  14 , where the cargo  16  is unloaded. This process is repeated until the boxcar  18  has been unloaded. 
   The process for use of the cross-dock system  10  to unload the cargo  16  from the boxcar  18  has been described. Of course, the process can be reversed and the cargo  16  can be loaded from the trailers  12 ,  14  into the boxcar  18  for storage in the boxcar  18  or transport by rail  19 , as desired. 
   Accordingly, a portable cross-dock system  10  is provided for loading and unloading railroad boxcars  18  (or other types of railroad cars) that is safe, strong, inexpensive (when compared to permanent types of cross-docks), portable over the highway, easy to assemble and disassemble, adjustable as to the floor height of the boxcar  18 , and versatile as to where the ramp  26  is placed and also as to where a trailer  12  or  14  can be loaded. Also, a plurality of the trailers  12 ,  14  can be used simultaneously. 
   The invention has been shown, described, and illustrated in substantial detail with reference to the presently preferred embodiment. It will be understood by those skilled in this art that other and further changes and modifications may be made without departing from the spirit and scope of the invention which is defined by the claims appended hereto.