Abstract:
Apparatus and method for cargo transfer. The method and apparatus encompass a shipping terminal with a marine-side and a land-side and a computer-controlled multi-level cargo-sled storage structure placed between the two sides. Cargo is received on the land-side from a land vehicle, transferred onto a cargo sled, which is then stored in the cargo-sled storage structure. When ready for shipping, the cargo sled is retrieved from the storage structure and stuffed into a cargo container on the marine-side, which is then loaded onto a ship. Method and apparatus reduce by up to a factor of eight the required number of cargo containers required to efficiently service shipping vessels.

Description:
BACKGROUND INFORMATION 
     1. Field of the Invention 
     The present invention relates to cargo transportation. More specifically, the present invention relates to the movement of cargo between the various transportation modes. More specifically yet, the present invention relates to apparatus and a method for moving cargo into and out of a cargo container at a shipping terminal. 
     2. Description of the Prior Art 
     For the past fifty years, much of worldwide shipping of goods in the general cargo liner business has taken place with the aid of cargo containers. The containerized cargo method involves the filling of a container with goods at the goods&#39; point of origin and then leaving the goods in that container until they reach their point of destination. In general there will be a number of intermediate way-stations to which the containers are taken. Key among these way stations are usually the shipping terminals at which the cargo-filled container begins and concludes, respectively, the ocean- or sea-going segment of its journey. For the sake of definitiveness in this discussion, these shipping terminals will be taken to be terminals for ocean-going cargo ships, that is, marine terminals. 
     The container in question is usually of a standardized size and shape, usually either 20 or 40 feet in outside length, with an outside width of 96 inches and a usual outside height of 8.5 feet. In general, the container is filled, also called “stuffed”, with numerous items, on pallets or not. This “stuffing” is, as stated, generally carried out at the point of origin by a combination of manual and machine operations, using fork-lifts and the like. Thus, the stuffing operation can be a tedious and often dangerous operation for the workers and one that always carries a certain risk of damaging the container itself. 
     The container has no rollers or other means to make it easily movable from one location to the next. It, therefore, requires a rollable chassis on which to be moved, for example, from the point of delivery at a terminal to the point where it is going to be loaded onto a ship. 
     At the conclusion of the ocean voyage, the process is reversed: the cargo-filled container is lifted from ship to marine-side, ultimately to be moved to and placed on ground transportation. Finally, with perhaps an intermediate stop, the cargo-filled container arrives at its point of destination where the container is emptied (“stripped”) of its goods, again through a combination of manual and mechanized effort. Finally, the empty container is taken back to the overseas terminal. 
     The usual situation is that, at the point of destination for the goods of a particular container, there are no goods waiting to be loaded into the container for its return trip. Consequently, most containers return empty to the marine terminal. This is an inefficient use of transportation equipment, be it land-, air-, or ocean-based. There is an additional built-in disadvantage where trucks are concerned, regardless of whether the container is being transported filled or empty, and that is that the size of containers, standardized decades ago at 10, 20, 30 or 40 feet, is smaller than the size allowed to be pulled on the highways today. The modern semi-trailer in the USA has an outside width of 102 inches and, commonly, a length of 53 feet. Thus, the trailer-trailer is often under-utilized, pulling a 20 or 40 foot container when it has a pulling capacity for 53 feet semi trailer. This means that the trucking industry significantly under-utilizes the highways by having trucks pull a lower shipping volume than allowed, yet overloads the highways by using more trucks than are necessary for the volume of goods being transported. 
     As can be seen, many disadvantages are associated with conventional containerized shipping. In addition to the ones set out above and to be summarized below, another even more significant one needs to be added, one connected to the dynamics of shipping. To see this, picture the cargo vessel as having a certain number of slots (also called cells) for containers. To maximize the use of assets tied up in this vessel, it must, to the extent practicable, be continually engaged in crossing the ocean with a full load of cargo, that is, fully loaded with filled cargo containers and with minimum time spent in port. Even ignoring container loss due to damage during the inland stuffing, stripping, and transportation, it is estimated that for this continual ocean-going activity to be maintained there must be a total of five containers to “support” every container slot on a ship. It is clear, for example, that within the 24-72 hour turn-around time of a ship in port, there must be a full container available at the terminal to take the place of the full container just off-loaded from the arriving ship. Furthermore, since the land shipment round trip often takes more time than the ocean round trip, there must already be a third filled container in transit toward the terminal as the re-loaded ship departs. In addition and as noted above, the full container that arrives at its destination and is stripped will not in general have goods ready at that point for re-stuffing; it must therefore be carried empty to another source of goods, or be returned empty to the terminal. And so forth. Moreover, the volume of cargo trade is almost always physically imbalanced and, as a result, containers must frequently be “repositioned” that is, moved as empty containers from a location of lower volume to a trading location of higher volume. This “repositioning” is a significant factor in the high cost of the present method of transporting cargo. 
     The need for such a large number of “support” containers for each container slot has a number of costs in addition to that associated with having capital tied up in the containers. These containers must be stored and staged somewhere during their transit, full or empty. This means that valuable real estate is taken up as an inherent feature of the present cargo transport method. Furthermore, to address the damage problem, the more containers there are, the more containers are damaged each year to the point where they need to be replaced. This damage occurs as a result of the necessity to shuffle containers from one location to another, that is, they are damaged while being moved on and off rolling stock, while being moved and stacked in storage areas, etc. 
     In short, the basic idea of 50 years ago, introduced to reduce perceived widespread loss in shipment, no longer works economically in the modern world. A number of attempts have been made to “patch” the problem. These include the following. A method and apparatus for loading automobiles into a cargo container are taught by Bates et al. (U.S. Pat. No. 4,919,582). Apparatus and methods for containerizing and de-containerizing a load are taught by Harp (U.S. Pat. No. 4,832,560; 1989). Similar apparatus is taught by Harp (U.S. Pat. No. 5,044,866; 1991). Harp (U.S. Pat. No. 5,129,778; 1992),teaches a method and assembly for “one-step” loading and unloading, using essentially the invention taught in Harp &#39;560 and Harp &#39;866. An adjustable load-carrying apparatus for fully utilizing transport enclosure space is taught by Halpin et al. (U.S. Pat. No. 5,454,672; 1995). Nevertheless, none of these prior art solutions really solves the problems set out above. 
     Therefore, what is needed is a way to reduce the costs, human and economic, inherent in the container-stuffing and -stripping of the present shipping process. What is further needed is a way to reduce the inefficiencies inherent in the mis-fit between container size and cargo-space of land-transportation means. What is yet further needed is a way to reduce the total number of containers needed to support each container slot of a working cargo ship, thereby reducing the total world container inventory, increasing asset utilization of marine terminals and inland transportation, and optimizing the infrastructure. 
     BRIEF SUMMARY OF THE INVENTION 
     Believing that what is needed is not a “patch,” but a complete shift in the worldwide approach to container cargo shipping, the present inventor presents an invention built around a “container sled” or “cargo sled” and method for using same. The heart of the invention is a sled that is loaded with cargo at the marine terminal, cargo that has been transported conventionally by inland means from its point of origin. Once the cargo has been loaded onto the cargo sled, it is then staged into a special multi-level Automated Storage/Retrieval System (AS/RS) warehouse that is located at the shipping terminal. From there, it is moved to and inserted into the container. The container is next placed on-board the ship. At the conclusion of the ocean voyage, the process is repeated in reverse: the loaded sled is removed from the container and moved to a location in the AS/RS warehouse at the terminal where the goods on the sled can be transferred to the ground transportation, leaving the sled behind in the terminal. Before being loaded onto a ship or ground transportation, the sled may be placed in the AS/RS warehouse at the terminal to await further processing. 
     Thus, the present invention is made up of both a device (the container sled) and a method that together provide a potential for changing the current large-scale shipping procedures in such as way as to reduce significantly the human and economic cost of cargo-handling at the points of origin and destination of the goods and in such a way as to drastically reduce the numbers of containers needed and to eliminate intermediate pieces of equipment on which to convey containers from one location to another. 
     More particularly, the sled of the present invention is a platform having outer dimensions approximately equal to the inner dimensions of standard containers. In one embodiment, extendable support rollers, for example, casters, are embedded on the underside of the platform so as to make the platform easily rollable across any reasonably smooth surface, such as the floor of a container or of a warehouse floor. By its nature, the support roller arrangement is able to support the weight of the fully loaded platform. Although in the Preferred Embodiment of the present invention, the support rollers are casters deployed by means of a threaded rod that runs the length of the sled and a linkage system attached to this rod, any of a variety of known means for deploying and maintaining these casters will occur to one skilled in the art upon reading the description of the present invention as presented herein. Furthermore, it is understood that the sled according to the present invention may comprise a rollerless or casterless platform, or a platform equipped with non-retractable rollers. 
     A number of spring-loaded guide rollers are placed at evenly spaced intervals around the perimeter of the platform. The guide rollers serve to keep the container or cargo sled centered, or in general, laterally stable, within the container. The platform may further include removable upright members, spaced around the platform perimeter, that serve as aids in securing cargo. Each of these upright members may also have a spring-loaded guide roller attached to its top end, to provide similar service to that of the guide rollers deployed around the perimeter of the platform. 
     In one sense, the method of the present invention is an entirely new shipping protocol that encompasses point-of-origin to point-of-destination shipping and that is built around the container sled. The heart of the invention, however, lies specifically in the process by which cargo coming into a marine terminal is transferred from ground transport to a cargo sled, and thence to a container and then to the ship, a process that will be mirrored at the marine terminal located at the other end of the cargo&#39;s ocean voyage. In that sense, the method of the present invention includes the steps of taking cargo that has arrived by land transport, loading it onto a cargo sled, and moving the cargo-laden container sled to a temporary holding location from which it is subsequently moved into a container, i.e., the cargo-laden container sled is used to stuff the container, and situating the thus-stuffed container into its slot on the ship. At the other end of the ship run, the method includes extracting the sled with attendant cargo from the container i.e., stripping the container, moving the cargo sled to a cargo holding facility and then, from the holding facility to surface transport that will move the cargo on toward its point of destination, after which the emptied container sled may be re-loaded with new cargo headed the other way, etc. In almost all cases, the cargo is removed from the cargo sled and loaded by conventional means into the inland conveyance. 
     Throughout this Summary, reference to “containers” or “cargo containers” can also be understood as not being limited to those containers commonly used with ocean-going vessels, or to any specific industry. For example, “containers” also includes those insulated and/or refrigerated containers, commonly referred to as “Reefer” containers, that are used for transporting perishable or frozen cargo. “Container” can further mean truck trailers of any size, equipped for dry cargo or refrigerated cargo as used, for instance, in the “roll-on, roll-off” (Ro-Ro) cargo transport industry. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows bottom, side, and end views of the container sled that constitutes the Preferred Embodiment apparatus of the present invention, including in particular a depiction of the casters and their reversible deployment mechanism. 
         FIG. 2  shows the upper/lower channel pair assembly of the apparatus of the Preferred Embodiment of the present invention and more detail of the raising and lowering of the casters. 
         FIG. 3  shows, at one end of the apparatus of the Preferred Embodiment, the receiving pocket and the modified fork-lift blade used in conjunction with it in moving the container sled of the Preferred Embodiment of the present invention. 
         FIG. 4  shows a plan view of the guide rollers used in an alternative embodiment of the apparatus of the present invention. 
         FIG. 5  shows the front view of guide rollers mounted on the floor of a container modified to accept a sled in accordance with the present invention, illustrating the relationship the guide rollers have to the center members of the sled platform corresponding to a particular embodiment of the apparatus of the present invention. 
         FIG. 6A  is a plan view of an AS/RS warehouse adapted for use in the goods-conveying method of the present invention. 
         FIG. 6B  is an elevational view of the AS/RS warehouse of FIG.  6 A. 
         FIG. 7  shows a partial view of an embodiment of the cargo sled according to the invention having fixed casters. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description of the Preferred Embodiment is directed to its use with common commercial cargo containers. Because commercial cargo containers are usually 40 feet in length and 96 inches in width, the container sled of the Preferred Embodiment has a length of approximately 39.5 feet (474 inches) and a width of between 88.5 and 92 inches all so as to fit snugly within the internal dimensions of the standard commercial cargo container. In the Preferred Embodiment, the container sled is designed by the appropriate choice and sizing of material to have a “life load” of 56,000 lbs. (This means that the sled can withstand at least 10,000 cycles of being loaded/unloaded with a load of 56,000 lbs.) Obviously, the present invention is not limited to use with a certain type or size of container. 
       FIG. 1  shows the container sled  100  of the Preferred Embodiment of the present invention in side, bottom, and end views, respectively. With reference to FIG.  1  and  FIG. 2 , it can be seen that two channel assemblies  20 —each having an upper channel  30  and a lower channel  40 —run the length of the longitudinally extended platform  10  that constitutes the major part of the container sled  100 . One of the channel assemblies  20  runs along the left side of the container sled  100  and one along the right. Attached in a transverse manner to the upper channels  30  are a number of beams  50 . These beams  50  are parallel to one another. Attached to the top of each of the beams  50 , i.e., the side of the beam not directly adjacent to one of the upper channels  30 , is a support surface  60  on which cargo is to be loaded prior to the container sled  100  being moved into a cargo container, shown in part in FIG.  4 . To prevent cargo from sliding sideways on the support surface  60  during transit, notches (not shown) 3 inches long and ½ inch wide lined with steel grommets are placed over the full length of the support surface  60  at two-foot intervals. Through these notches either strapping or quick-release-type lashings can be introduced to secure the cargo relative the support surface  60 . 
     A caster-linkage system designed to permit the container sled  100  to be freely rolled in a traditionally configured container is indicated in the central view of FIG.  1 . It includes transverse links  70  each of which is pivotably connected at one end to one of a plurality of collars  71  that are threaded onto a threaded rod  75  that runs the length of the container sled  100 . The threaded rod  75  is positioned along the midline of the container sled  100  and accessible at each end of the container sled  100  so that casters  80 —that in the Preferred Embodiment have a diameter of between two and four inches—attached to each of the lower channels  40  may be deployed by rotation of the threaded rod  75 . This rotation, either clockwise or counterclockwise, is performed in the method of the Preferred Embodiment of the present invention by the use of pneumatic power tools. The remaining end of each of the links  70  is pivotably connected to the container sled  100 , and a middle portion of each of the links  70  is attached to one of the lower channels  40 . In this way, when the threaded rod  75  is caused to turn, the collars  71  move longitudinally relative to the threaded rod  75 , and each link is caused to move in angular motion; the ends attached to the container sled  100  undergo no displacement. 
     Paying particular attention to the side and end views, respectively, of the container sled  100  (top and bottom drawings, respectively, in FIG.  1 ), a number of removable upright members  90  can be observed attached along the perimeter of the container sled  100  at evenly spaced intervals. These upright members  90  serve two purposes: to help keep cargo on the support surface  60  of container sled  100 , and to help keep the container sled  100  centered within the surrounding container. Spring-loaded upper guide-rollers  95  are positioned at the top end of each of the upright members  90 . An additional set of these spring-loaded guide-rollers, lower guide-rollers  96 , is attached to the container sled  100  itself and spaced along its perimeter at even intervals. These additional spring-loaded guide-rollers  96  further serve to keep the container sled  100  centered within a container both as it is being introduced to the container and during transit. 
       FIG. 2  shows in detail both a side view and an end view of a portion of one of the channel assemblies  20 , including one of the upper channels  30  and one of the lower channels  40 . Each of the upper channels  30  and each of the lower channels  40  is constructed from C-channel stock. A number of upper-channel ramp-blocks  32  is attached at evenly spaced intervals along the upper channels  30 . For the purpose of illustration, only one of these upper-channel ramp-blocks  32  is shown in FIG.  2 . Each of the upper-channel ramp-blocks  32  has a cross-section in the shape of a truncated right-triangle, the hypotenuse of which is presented to one of a set of underlying lower-channel ramp-blocks  42 , as is shown in the side view of FIG.  2 . Each of the lower channels  40  fits within the open side of one of the upper channels  30 . The lower-channel ramp-blocks  42  are attached at evenly spaced intervals, with the same spacing as that of the upper-channel ramp-blocks  32 , to each of the lower channels  40 . Each of the lower-channel ramp-blocks  42  has a cross-section in the shape of a truncated right triangle, the hypotenuse of which is supplementary to the hypotenuse of the overlying upper-channel ramp blocks  32 . Each of the lower-channel ramp-blocks  42  is attached to a plate  43  that in turn is attached across the open side of the lower channels  40 . Casters  80  are attached to the underside of the lower channel  40 , in such a manner that each of the casters  80  is free to rotate 360° about a vertical axis. Because of the supplementary nature of the mating hypotenuses of the upper and lower ramp blocks, the casters  80  are deployed when the threaded rod  75  is caused to turn in one direction, i.e., clockwise, and, alternately, retracted when the threaded rod  75  is caused to turn in the opposite direction, i.e., counter-clockwise. 
     In the Preferred Embodiment apparatus, a pair of fork-blade pockets  110  is located at each end of the container sled  100 , fore and aft. Detail of these fork-blade pockets  110  can be seen with reference to  FIG. 3 , which depicts one of the fork-blade pockets  110  as recessed between the support surface  60  and a lower surface  130  of the container sled  100 . Each of the fork-blade pockets  110  is adapted to receive a fork-blade, and, in the Preferred Embodiment, each can also receive and accommodate, by means of a slot  115 , a catching-bar  116  attached to the distal end of a modified fork-blade  200 . This slot  115  prevents the container sled  100  from disengaging from the modified fork-blade  200  when the forklift is moved backwards. 
     In the method of the Preferred Embodiment of the present invention, cargo is delivered to a marine terminal from a inland transport means, i.e., air-, or ground-transport, but usually a truck. It is then loaded onto a container sled  100  until the container sled  100  is filled, at which time or shortly thereafter a fork-lift with a pair modified blades  200  approaches the container sled  100  and slips its pair of modified fork-blades  200  into a pair of fork-blade pockets  115  so as to affirmatively couple to the container sled  100 . In the meantime, the casters  80 , which were retracted during the filling of the container sled  100  are deployed so as to make the container sled  100  mobile. The fork-truck is then used not to lift the sled but to shuttle it horizontally across and through the marine terminal until it reaches a standardized container. The fork-truck is then used to usher the loaded container sled  100  into the standardized container, after which it disengages from the loaded container sled  100 . The casters  80  on the bottom of the container sled  100  are then retracted, by the means described earlier, using a pneumatic tool and the container sled  100  then sits securely on the floor of the container. The container in turn is then placed aboard the ship by the usual well-known methods for such maneuvers. At the marine terminal at the other end of the ship&#39;s voyage, the process is reversed. 
     In an alternate preferred embodiment of the apparatus of the present invention, the guide rollers are affixed to the container and neither guide rollers nor casters are present on a container sled  101 . There are a number of other features added to the sled  101  to accommodate this change. This other embodiment is depicted in FIG.  4  and FIG.  5 . 
       FIG. 4  shows a plan view of the alternate apparatus, showing eight floor guide rollers  180  that are each mounted on one of guide posts  181 . These guide posts  181  are in turn mounted to the floor of a container  1 . These floor guide rollers  180  are configured in pairs and are mounted on the floor of the container  1  in a manner such that each pair straddles the longitudinal midline of the container  1 . Running between sets of floor guide rollers  180  when the container sled  101  is introduced to the container are certain elements affixed to the bottom of the container sled  101 , namely a left sled rail  131 , a central sled rail  130 , and a right sled rail  132 , each of which runs the length of the container sled  101 . All three sled rails are shown in end view in FIG.  5 . The guide rollers  180  that guide and control the central sled rail  130 . Also indicated in  FIG. 5  is the fact that the container sled  101  no longer is equipped with casters  80 . See FIG.  1 . This embodiment is, therefore, suited for use with a pallet jack. Ideally, the pallet jack would have tines approximately 40′ in length, so that it can reliably lift the container sled  101 . It is also possible to use half-size sleds that can be lifted with already known pallet jacks having 18′ long tines, and that two sleds  101  be stuffed into a container. 
       FIG. 7  shows a third embodiment according to the invention, a sled  102  fitted with fixed casters  81 . In order to distribute the point load from the casters on the floor of the container  1 , the container is fitted with ¼″ steel reinforcing plate. Elastic bumpers  82  are attached to each end of the sled  102 . The overall length of the sled  102  with the bumpers  82  is slightly longer than the inside length of the container  1 . The bumpers  82  provide sufficient elasticity that, when the sled  102  is stuffed into the container  1  and the container door closed, the bumpers  82  will fit snugly up against the end walls of the container  1  and prevent the sled  102  from moving in a longitudinal direction relative to the container  1 . In general, the elastic bumpers  82  can be used with any embodiment of the sled  100  and  101 , as an additional means of securing the load in the container  1 , and are shown in  FIG. 5  on sled  101 . 
       FIGS. 6A and 6B  schematically illustrate a specially equipped marine terminal  300  that includes a marine-side terminal  300 A, a land-side terminal  300 B, a crane area  310 , a container yard  320 , and an automated warehouse  210  adapted for use in the method of the present invention.  FIG. 6A  is a plan view and  FIG. 6B  an elevational view of the marine terminal  300 . The warehouse  210  has multiple levels  250 A-E of sled storage bays  220 , as well as a computer-controlled automated storage/retrieval system (AS/RS)  230 . For purposes of illustration only, five levels  250 A-E are shown. It should be understood, however, that the warehouse  210  may have fewer or more levels. The marine terminal  300  also includes a marine-side loading ramp  340  and a land-side loading ramp  340 A, positioned on opposite sides of the warehouse  210 . A cargo ship S is shown on the marine-side and tractor-trailer rigs T for transporting cargo over land are shown on the land side of the marine terminal  300 . The warehouse  210  is ensconced by a first enclosed apron  350  on the marine side, and a second enclosed apron  350 A on the land side. It is on these aprons  350 ,  350  A that the stuffing and stripping of a container C or the loading/unloading of a yard chassis takes place. The width of the illustrated warehouse  210 , by way of example, is five 40-foot container lengths. The middle forty feet of the width of the warehouse  210  contains the AS/RS  230 , which also controls a stacking/retrieval crane (SRC)  231  and a satellite crane  232  that is adapted to hold a cargo sled  100 . This middle area, referred to as the AS/RS area  233 , is open the full height of the warehouse  210 , as shown in  FIG. 6B , so that the SRC  231  can deposit/retrieve sleds  100  in a plurality of storage bays  220  on the various levels. The storage bays  220  are the length of two cargo sleds  100  and rows of storage bays  220  are provided on either side of the AS/RS area  233  for each level  250 A- 250 E. Certain storage bays  220  on the ground floor of the warehouse  210  are used as passageways  235  for the sleds to be moved into the AS/RS area  233 , as shown in FIG.  6 A. The SRC  231  has enough capacity to lift, store and retrieve a cargo sled  100  that is loaded to its maximum weight and volume limits to any of the levels  250 A- 250 E and any of the storage bays  220 . The warehouse  210  is equipped with sufficient empty cargo sleds  100 , and these are used for export cargo. After cargo has been placed on these empty sleds  100 , the loaded sleds  100  are stored in the warehouse  210  to await arrival of the ship. In the Preferred Embodiment, the AS/RS  230  including the stacking/retrieval crane  231  and the satellite crane  232  are computer-controlled. Thus, there is no need to provide access to persons to the warehouse  210 , except for maintenance and repair purposes. This provides greater security for storing cargo. 
     It should be clear that regardless of which embodiment of the apparatus is used—the sled  100  with casters  80 , the sled  101  with rails, or the sled  102  with fixed casters  82 —the same general system of peripheral equipment will be used, all as just set out. 
     Although some degree of detail has been given concerning the Preferred Embodiment of the present invention, even to the point of dimensions of the apparatus of the Preferred Embodiment, it is not meant by this illustrative example to limit in any way the overall scope of the present invention.