BACKGROUND OF THE INVENTION 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 modes by which it is transported. More specifically yet, the present invention relates to an apparatus and method for moving cargo into and out of cargo containers at shipping terminals and in particular at terminals for ocean-going shipping.

2. DESCRIPTION OF PRIOR ART For the past fifty years, much of world-wide shipping of goods has taken place in the form of containerized cargo. The containerized cargo method involves the filling of a container-usually of a standardized size and shape-with goods at the goods'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 or concludes the longest segment of its journey from origin to destination. 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 containers in question are 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, each of them will be filled ("stuffed") with numerous items, on pallets or not. This"stuffing"is, as stated, carried out at the point of origin and is generally carried out by a combination of manual and machine operations, using fork-lifts and the like. Because of the interest of maximizing space, the good are made to fill up as close to 100% of the container's inside volume as

possible. Thus, the stuffing operation can be a tedious and often dangerous operation for the workers and equipment, one that always has a certain risk of damaging the container itself.

The containers generally have no rollers or other means to make them easily moved from one location to the next. They therefore often require rollable chassis on which to be moved, for example from the point of delivery at a terminal to the point where they are going to be loaded onto the ship.

At the conclusion of the ocean voyage the process is reversed, and the cargo-filled container is lifted from ship to ship-side, ultimately to be moved to and placed on ground transportation. Finally, with perhaps another 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.

The usual situation is that at the point of destination for the goods in a particular container there are no goods with which to load the container for its return trip.

Consequently, most containers return empty. 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 containers being carried are filled or empty, and that is that the size of the containers, standardized decades ago, does not"fit"the most common semi-trailers on the road today; they are too small, a fact that can be observed by anyone who notices these cargo containers being carried by trucks. Modem semi-trailers have outside widths of 102 inches and, commonly, lengths of 53 feet. This means that the cargo containers significantly under-utilize the shipping volume available on these trucks, a significant inefficiency.

As can be seen, many disadvantages-some of them not present originally-are associated with traditional 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 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. 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 the ship. It is clear, for example, that within the 24-72 hour turn- around time of a ship in port, there must be a stuffed container available at the terminal to take the place of the stuffed 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. And so fourth.

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 somewhere during their transit, stuffed 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 will be damaged each year to the point where they need to be replaced. This replacement-requiring damage occurs while the containers are being moved on and off rolling stock, while they are being move 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 modem 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 is taught by Bates et al. (U. S.

Patent No. 4,919,582). An apparatus and methods for containerizing and de-containerizing a load is taught by Harp (U. S. Patent No. 4,832,560; 1989). A similar apparatus is taught by Harp (U. S. Patent No. 5,044,866; 1991). Harp (U. S. Patent No. 5,129,778; 1992) teaches a method and assembly for"one-step"loading and unloading using essentially the invention taught in Harp'560 and Harp'866. An adjustable load-carrying apparatus for fully utilizing transport enclosure space is taught by Halpin et al. (U. S. Patent No. 5,454,672; 1995). Nevertheless, none of these prior art solutions really solve 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.

SUMMARY OF THE INVENTION Believing that what is needed is not a"patch"but a complete shift in the worldwide approach to cargo shipping, the present inventor presents an invention built around a "container sled"apparatus 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 by inland means from its point of origin without having to have been stuffed into a container. Once the container sled is loaded it is rolled on self-contained rollers to the container. The container is next placed on-board the ship. (In an alternative, the container may already be aboard the ship when the goods-laden sled is rolled into it.) At the conclusion of the ocean voyage, the process is repeated, the sled being rolled out of the container, then to a location in the terminal where the goods on the sled can be transferred to the ground transportation, leaving the sled behind in the terminal.

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 apparatus of the present invention is a platform having outer dimensions approximately equal to the inner dimensions of standard containers, a platform in which extendable support rollers (casters) are embedded on the underside 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 their 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 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 support rollers will occur to one skilled in the art upon reading the description of the present invention as presented herein.

At equal spaced intervals around the perimeter of the platform may be a number of spring-loaded guide rollers that serve to help keep the container sled centered, or in general, laterally stable, while within a container. The platform may further include removable upright members that spaced around the platform perimeter to serve as aids in platform loading. 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.

Although in one sense, the method of the present invention is an entire new shipping protocol-point-of-origin to point-of-destination-built around the container sled, its heart lies specifically in the process by which cargo coming into a marine terminal is transferred from ground transport to a container sled and then to the ship, a process that will be mirrored at the marine terminal located at the other end of the cargo'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 container 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, it includes moving the sled with attendant cargo out of the container (i. e., stripping the container), moving the container sled to a cargo holding point and then, from the holding point 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.

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.

DESCRIPTION OF THE DRAWINGS Figure 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.

Figure 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.

Figure 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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The following description of the Preferred Embodiment is directed to use with common commercial cargo containers and is by way of example. Because commercial cargo containers are usually 40 feet in outside length and 96 inches in outside width, the container sled of the Preferred Embodiment has a length of approximately 39.5 feet (275 inches) and a width of between 88.5 and 92 inches all so as to fit snugly within the internal dimensions of. the referenced standardized container. In the Preferred Embodiment, the container sled is designed by the appropriate sizing of and choice of material to hold a life load (i. e., a fatigue strength for a cycle life of more than 10,000 loading cycles) 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, end, and bottom views, respectively. Two pairs of mated channel assemblies 20-each pair having an upper channel (shown as element 30 in Fig. 2) and a lower channel 40-run the length of the longitudinally extended platform 10 that constitutes the major part of the container sled 100. Attached in a transverse manner to the upper channels 30 are a number of beams 50. These beams 50 are all parallel to one another.

Attached to the top (i. e., the side that is not attached to the upper channels 30) of the beams is a support surface 60 on which cargo is to be loaded prior to the container sled 100 being moved into a cargo container (not shown). To prevent cargo from sliding sideways on the support surface 60 during transit, notches (not shown) of 3 inches long and 1/2 inch wide, lined with steel grommets are placed over the full length of the support surface 60 at 2 feet intervals. Through these notches either strapping or quick-release-type lashings can be applied to secure the cargo relative the support surface 60.

The caster-linkage system, including transverse links 70, are shown in the central view of Fig. 1. Each of these links 70 is pivotably connected at one end to collars 71 which 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 rollers 80-that in the Preferred Embodiment have a diameter 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 end and side views of the container sled 100 (top and bottom drawings 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 guide-rollers 95 are positioned at the top end of each upright member 90. An additional set of these spring-loaded guide-rollers is attached to the container sled 100 itself and spaced along its perimeter at even intervals. These additional spring-loaded guide-rollers 95 further serve to keep the container sled 100 centered within a container.

Fig. 2 shows in detail both a side and an end view of a portion of the mated upper and lower channel assemblies 20, made of respectively of upper channels 30 and 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 are attached at evenly spaced intervals along the upper channel 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. The lower channel 40 fits within the open side of the upper channel 30. A number of the lower-channel ramp-blocks 42 are attached at evenly spaced intervals (i. e., the same spacing of those 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 block. 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. Rollers 80 are attached to the underside of the lower channel 40, in such a manner that each of the rollers 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 rollers 80 are deployed when the threaded rod 75 is caused to turn in one direction (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 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 each can also (in the Preferred

Embodiment) 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 rollers 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 rollers 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's voyage, the process is reversed.

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.