[0001] Modular Cell Elevator for Container Ship

CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present application claims priority to U.S. Provisional Patent Application No.

61/455,773, filed October 26, 2010 and entitled "Modular Cell Elevator for Container Ship."

BACKGROUND OF THE INVENTION

[0003] The present invention relates generally to a modular cell elevator for use on a container ship in combination with a spreader bar and crane to load containers onto and/or to remove containers from the container ship.

[0004] Container ships frequently store containers in cells within the hold of the ship. A cell is a vertical compartment, generally several decks high, extending from a container storage deck inside the ship upward to a cell hatch on the weather deck of the ship. Each cell is generally sized to accommodate the length and width of shipping containers, which are generally constructed in standard sizes, such as those sizes specified by the International Standards Organization ("ISO"). The standard sizes are generally twenty feet, forty feet, and forty-five feet long.

[0005] Spreader bars, which are well known in the container handling industry, are the end effectors of a crane used to "pick" and "place" cargo containers or other such loads. Spreader bars are typically attached by mechanisms such as cables or hooks to cranes of various types (e.g., gantry cranes, boom cranes, straddle cranes, etc.) or the like in order to move the cargo which has been engaged by the spreader bar from one site to another. Spreader bars are used all over the world in military and commercial applications.

[0006] One particular application of spreader bars in the cargo handling industry is for loading and unloading cargo to and from ships either docked in port or in an offshore loading/unloading facility. Typically, to pick a container from a cell on a container ship, containers are first removed from above the storage deck, a hatch on the top of the cell is opened, providing access for the spreader bar to be lowered into the cell to engage the top-most container in a vertical stack of containers in the cell. The spreader is carefully lowered through the hatch. Despite mechanical gathers at the top of the cells, even the best of operators generally must make several attempts before finally entering the cell. Once the spreader bar is inside the cell and immediately above the container, the connecting mechanisms located at the four corners of the spreader bar are connected with the mating mechanisms of the container to fasten the spreader bar to the top of the container. The container is carefully lifted up the cell and through the hatch and then transported to its offloaded location. The process is repeated to remove subsequent containers in the cell.

[0007] Similarly, to place a container into a cell, the container is connected to the spreader bar as described above, and then lifted over the open cell. The container is carefully lowered through the cell hatch and into the cell. The container is typically released from the spreader bar and the spreader bar is carefully raised through the cell and the cell hatch and transported to another container for placing into a cell. The lowering and raising of the spreader bar through the cell hatch and the cell is a delicate and time-consuming process.

[0008] Therefore, it would be beneficial to develop a transfer mechanism that would eliminate the need for the spreader bar to be raised and lowered through the cell hatch and the cell. Such a transfer mechanism would increase productivity in comparison to conventional methods because it would ease the task of picking and placing containers. Also, since the transfer mechanism would work in parallel with the crane and spreader bar, the transfer mechanism would reduce the need for the spreader bar to enter the hatch, a major portion of the crane cycle, and reduce the time required to load and/or unload a container ship.

[0009] Further, it would be desirable to develop a transfer mechanism capable of raising, lowering and/or moving containers in laterally-adjacent cells to reduce the time required to load and/or unload a container ship. More specifically, it would be beneficial to develop a modular cell elevator that is capable of raising and/or lowering a container in one cell, while simultaneously transporting another container into or out of a laterally-adjacent cell.

BRIEF SUMMARY OF THE INVENTION

[0010] Briefly stated, one aspect of the preferred invention is directed to a modular cell elevator for transferring two laterally-adjacent containers through a container cell opening of a ship and into or out of first and second container cells below the elevator. The elevator includes a frame removably mountable to an open hold of the ship. The frame is sized and shaped to extend from one side of the first container cell to an opposing side of the second container cell. The frame includes an opening having a first opening laterally-adjacent to a second opening. The opening is sufficiently large to simultaneously pass the two containers therethrough. A trolley is movably mountable on the frame. The trolley is movable between a first position for raising or lowering one of two containers from the first container cell and a second position for raising or lowering the other of the two containers from the second container cell. At least one hoist is mounted to the trolley and releasably engageable with each of the containers to transfer each container through the opening of the frame between a first position proximal and above the first and second openings of the frame and a second location below the first and second openings of the frame. At least one support is mounted on the frame. The at least one support being is releasably engageable with each container in the first position to support each container in the first position.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF TFIE DRAWINGS

[0011] The foregoing summary, as well as the following detailed description of the preferred invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

[0012] Fig. 1 is a top plan view of a container ship with modular cell elevators in accordance with a preferred embodiment of the present invention;

[0013] Fig. 2 is a schematic diagram depicting a procedure for raising and/or lowering a container by a crane and a modular cell elevator of Fig. 1 ;

[0014] Fig. 3 is a perspective view of the modular cell elevator shown in Figs. 1 and 2;

[0015] Fig. 4 is a perspective view of at least a portion of a container ship proximate the crane, wherein the modular cell elevator is spaced-apart from the container ship;

[0016] Fig. 5 is a perspective view of at least a portion of a container ship proximate the crane, wherein the modular cell elevator is placed by the crane onto the container ship and over a pair of container cells;

[0017] Fig. 6 is a top perspective view of at least a portion of the container ship proximate the crane, wherein the modular cell elevator is preparing to raise a first container from an open hull of the container ship;

[0018] Fig. 7 is a perspective view of at least a portion of the container ship proximate the crane, wherein the modular cell elevator has raised the first container above the open hull of the container ship;

[0019] Fig. 8 is an enlarged perspective view of at least a portion of a container ship proximate the crane, wherein the modular cell elevator is preparing to raise a second container from the open hull of the container ship and the crane is preparing to attach to the first container;

[0020] Fig. 9 is a enlarged perspective view of at least a portion of the container ship proximate the crane, wherein the modular cell elevator is preparing to raise the second container to the top of the open hull of the container ship and the crane is preparing to move the first container up and away from the container ship;

[0021] Fig. 10 is a enlarged perspective view of at least a portion of the container ship proximate the crane, wherein the modular cell elevator has raised the second container to the top of the open hull of the container ship and the crane is moving the first container up and away from the container ship;

[0022] Fig. 11 is a perspective view of at least a portion of the container ship proximate the crane, wherein the modular cell elevator is preparing to raise a third container from the open hull of the container ship and the crane has placed the first container onto another container ship or a dock, for example;

[0023] Fig. 12 is a perspective view of at least a portion of the container ship proximate the crane, wherein the modular cell elevator has raised the third container above the open hull of the container ship and the crane is moving the second container up and away from the container ship; and

[0024] Fig. 13 is a perspective view of at least a portion of the container ship proximate the crane, wherein the modular cell elevator is preparing to raise a fourth container from the open hull of the container ship and the crane has placed the second container onto the other container ship or a dock, for example.

DETAILED DESCRIPTION OF THE INVENTION

[0025] Certain terminology is used in the following description for convenience only and is not limiting. The terms "left," "right" and "upper" designate directions in the drawings to which reference is made. The terms "inwardly" and "outwardly" refer to a direction toward and away from the geometric center of the device and designated parts thereof. Unless specifically set forth herein, the terms "a," "an" and "the" are not limited to one element but instead should be read as meaning "at least one." The terminology includes the words noted above, derivatives thereof and words of similar import.

[0026] Referring to the drawings in detail, wherein like numerals indicate like elements throughout, Figs. 1-13 show a preferred embodiment of a modular cell elevator ("elevator"), generally designated 10, for transferring at least one container 12, and preferably at least two laterally-adjacent containers 12 (i.e., left and right), between a first location proximal or at a mouth or hatch opening 14 (Figs. 4, 7 and 8) of one or more laterally-adjacent container cells 16 ("cells") (Figs. 1 and 4) on a container ship S, and a second location below the elevator 10 and within one of the cells 16. The laterally-adjacent container cells 16 are not limited to any particular location on the ship S, such as the first two cells 16 of the ship S, but may be two or more of any of the many container cells 16 of the ship S.

[0027] The elevator 10 can be used during loading ("placing") of the containers 12 onto the ship S and into the cells 16 and also during offloading ("picking") of the containers 12 from the ship S and the cells 16. Typically, the containers 12 are one of an ISO standard size of twenty feet, forty feet, or forty-five feet in length, although the containers 12 can also be of other lengths and/or sizes. The elevator 10 may be in the form of a double bay modular cell elevator (Figs. 3 and 5) or a quad cell elevator, for example. Further, the elevator 10 may be used with a ship S having longitudinally aligned or extending cells 16 (i.e., extending in the direction of bow toward stern) or laterally aligned or extending cells 16 (i.e., extending in the direction from port toward starboard) (Figs. 1 and 4-7).

[0028] Referring to Figs. 4-13, each cell 16 preferably includes at least four spaced-apart cell guides 20 which extend vertically between the top (i.e., upper deck of the ship S) and the bottom of the cell 16, with each cell guide 20 located at one corner of the cell 16. The cell guides 20 are preferably in the form of angle steel, the top ends of which may be outwardly flared to more easily receive a container 12. The cell guides 20 generally define the length and width of the cell 16, such that one cell guide 20 is preferably positioned at each of the four corners of any cell 16. Bulkheads (not shown) can be installed between longitudinally and laterally-adjacent cell guides 20 to further define a cell 16, but such bulkheads are not necessary.

[0029] Referring now to Figs. 3-13, the elevator 10 preferably includes a generally

rectangularly-shaped, open frame 24 that is removably mountable to an open hold of the ship S on the upper deck of the ship S. The frame 24 preferably includes a base 32 with two opposing longitudinal sides 24a and four opposing lateral sides 24b surrounding and defining an opening 25 (Fig. 3) through the frame 24. The opening 25 preferably includes a first opening 25a laterally- adjacent to a second opening 25b. Each of the first and second openings 25a, 25b are preferably sufficiently sized and shaped so that a single container 12 can pass therethrough. As shown in Fig. 3, the frame 24 may include a divider 24c that extends generally parallel to the longitudinal sides 24a, extends through the center of the opening 25, and, therefore, defines each of the first and second openings 25a, 25b. However, the frame 24 may function equally as well without the divider 24c. At least a portion of each of the longitudinal sides 24a and two of the lateral sides 24b preferably directly engage and/or contact the upper deck of the ship S. The remaining two lateral sides 24b are preferably vertically spaced-above the lower two lateral sides 24b, thereby giving the frame 24 a generally rectangular, three-dimensional shape.

[0030] The frame 24 is mountable over at least one cell 16 at the hatch opening 14 and preferably the frame 24 is sized and shaped to extend over at least a portion of each of a pair of laterally-adjacent container cells 16 of the ship S. Preferably, an inside or interior area of the frame 24 includes a central opening 25 at least slightly longer and wider than the particular laterally- adjacent containers 12 which are being transported, so that the containers 12 can pass through the frame 24 simultaneously, if desired. It is preferred that the frame 24 is at least partially adjustable or adaptable to accommodate the size and/or shape of different ships. For example, the frame 24 may be slightly adjusted to accommodate different lateral distances between adjacent cells 16 that might be found on different ship or between cells 16 on the same ship S. In addition or alternatively, the frame 24 may include removable attachments or feet (not shown) to selectively increase or decrease the overall size and shape of the frame 24. This adjustment may be accomplished by releasably engaging the longitudinal sides 24a and the lateral sides 24b of the frame 24, for example.

[0031] The frame 24, when connected to a spreader bar 26 with twist locks 28 of a crane 13, as described in detail herein, is preferably transportable between different cells 16 and between a cell 16 and a location off the ship S, such as a pier, a dock, a transport vehicle or even another ship, by suitable mechanisms such as a crane 13 provided to move the containers 12. However, the frame 24 or a plurality of frames 24 can be fixedly connected to the deck on the ship S over a cell 16 or a plurality of cells 16 or mounted for movement along and/or across the deck on a suitable carriage (not shown) to service the various cells.

[0032] As shown in Fig. 3, the frame 24 preferably includes cell guide extensions 34 which extend vertically or upwardly from each of the four lower corners of the base 32 of the frame 24 and at a general midpoint of each lateral side 24b. The cell guide extensions 34 are preferably at least as high as the height of a single container 12. The cell guide extensions 34 may be formed of angle steel and in the same size and/or shape as the angle steel making up the cell guides 20. Preferably, the base 32 and the cell guide extensions 34 are constructed of a high strength steel or other suitable material and treated with an outer coating to protect against rust and corrosion from rain, salt and other corrosives which might structurally weaken the frame 24 and the cell guide extensions 34.

[0033] Referring to Figs. 2, 3, 6-11 and 13, the elevator 10 preferably includes a carriage or trolley 17 movably mountable on the frame 24. Specifically, the trolley 17 is preferably connected to each upper lateral side 24b of the frame 24 by casters, rollers, a track system or bearing mechanisms 19 (Fig. 3), which allow laterally movement of the trolley 17 across the frame 24. For example, each upper lateral side 24b of the frame 24 may include a linear groove sized and shaped to receive a wheel of the bearing mechanism 19 therein. Opposing ends of each groove of each upper lateral side 24b may include a stop or abutment to prevent movement of the trolley 17 beyond a certain outer lateral point.

[0034] The trolley 17 is preferably movable between a first position (Figs. 6 and 7) for raising and/or lowering one of the two laterally-adjacent containers 12 from one of the pair of adjacent container cells 16 and a second position (Fig. 13) laterally spaced-apart from the first portion for raising and/or lowering the other of the two laterally-adjacent containers 12 from the other of the pair of adjacent container cells 16. It preferably takes the trolley 17 approximately ten seconds to shift or move from the first position (Figs. 6 and 7) to the second position (Fig. 13), but the trolley 17 can be modified to move quicker or slower between the first and second positions depending on the design of a particular embodiment. The trolley 17 includes at least one and preferably two longitudinally-extending support beams or trusses 21 (Fig. 3). The trusses 21 are shown in a spaced-apart configuration, but the present invention is not limited to this configuration. Each truss 21 extends from one upper lateral side 24b to the opposing upper lateral side 24b of the frame 24 and generally parallel to each longitudinal side 24a of the frame 24. The trusses 21 are preferably fixedly attached to each other, but the trusses 21 may be laterally movable relative to each other.

[0035] Referring to Fig. 3, in the preferred embodiment, the elevator 10 further includes at least one and preferably four spaced-apart lifting devices or hoists 30, which are each preferably disposed beneath and at least a portion thereof is preferably fixed to the trusses 21 of the trolley 24. At least a portion of the hoists 30 typically move the containers 12 between the frame 24 and the interior of the cell 16. The hoists 30 are configured to releasably engage a mechanism on the top of the container 12, preferably upper corner castings 12a of the container 12, which are depicted in Fig. 4. The castings 12a are more fully shown and described in U.S. Patent No. 6,572,319, which is assigned to Ablaze Development Corporation and incorporated herein by reference. Corner castings 12a are the standard fittings at the corners of ISO containers.

[0036] As shown in Fig. 3, each hoist 30 further preferably includes a winch 40. The winch 40 includes a winch motor 42, a winch reel 44 rotatably mounted to the trolley 17 and driven by the motor 42, and a winch cable 46 wound on the winch reel 44. The winch cable 46 can simply be wire rope, which is well known, but preferably the winch cable 46 includes lines (not shown) integrated with the load bearing portion of the cable 46, which can transmit electrical power, hydraulic power, and/or signals for reasons that are apparent to one having ordinary skill in the art based upon a review of the present disclosure. A first or connected end (not shown) of the winch cable 46 is fixedly attached to the winch reel 44. An opposite second end (not shown) of each winch cable 46 is attached to a pulley 45 or other lifting or connecting device rotatably attached to a lifting frame 47, as described in detail below.

[0037] Referring to Figs. 3 and 8-10, the elevator 10 preferably further includes the lifting frame 47 for directly engaging the upper corner castings 12a of at least one of the containers 12 for raising and/or lowering the particular container 12. The lifting frame 47 is preferably sized and shaped to fit within the central opening 25 of the frame 24, such that a length of the lifting frame 47 is slightly, but sufficiently, less than a length of each longitudinal side 24a of the frame 24. Further, a width of the lifting frame 47 is preferably slightly, but sufficiently, less than half of a length of each lateral side 24b of the frame 24. At least a portion of at least one and preferably four spaced-apart pulleys

45 are preferably fixedly attached to the lifting frame 47 to raise and/lower the lifting frame 47 with respect to the trolley 17 and the frame 24. Four hoists 30 and four pulleys 45 are preferred to properly balance the lifting fame 47 during operation.

[0038] The lifting frame 47 may include at least one and preferably four connectors, each preferably in the form of twist locks 50 (Fig. 3), for releasably engaging the upper corner castings 12a of at least one of the containers 12. In the preferred embodiment, a lower surface of the lifting frame 47 includes at least two and preferably four spaced-apart twist locks 50 proximate the comers of the lifting frame 47. Each twist lock 50 includes a key 64 which is insertable into and directly engageable with the top side of an upper corner casting 12a on the container 12.

[0039] Twist locks 50 are known components in the container handling industry and include the "bayonet-type" shear keys 64 that fit into the upper corner castings 12a of the container 12. When inserted into an upper corner casting 12a, an actuator (not shown) within the twist lock 50 rotates the key 64 to lock the key 64 into the upper corner casting 12a. In the preferred embodiment of the present invention, the twist locks 50 are hydraulically, pneumatically and/or electrically actuated to effect the required rotational movement and are connected by hydraulic hoses (not shown) to a remote hydraulic system (not shown). The hydraulic hoses can be contained within the winch cable

46 or can be separate from the winch cable 46. Although a hydraulic system is preferred, other types of systems, such as electrical or mechanical, can be used as well. Features of the twist lock 50 are more fully shown and described in U.S. Patent No. 6,572,319, the description of which is omitted herein. The elevator 10 is not limited to the inclusion of the lifting frame 47, as the connectors or twist locks 50 may be directly attached to the second end of each winch cable 46.

[0040] As shown in Figs. 3 and 4, the frame 24 preferably also includes a plurality and more particularly at least spaced-apart eight supports or corner casting pins 72 for releasably engaging upper or lower corner castings 12a, 12b of the container 12 and supporting the container 12 on the frame 24 when the container 12 is in the first location. The casting pins 72 can be located anywhere on the longitudinal sides 24a of the frame 24, the lateral sides 24b of the frame 24, or a combination thereof including at each corner of the frame 24. However, at least one pin 72 is preferably located proximate to each corner of the frame 24 and is movable on the frame 24, preferably horizontally or laterally, between a container disengaged position (i.e., inward) and a container engaged position (i.e., outward). In the container disengaged position, the corner casting pins 72 are each preferably retracted into a recess 74 in the frame 24, such that no part of the corner casting pins 72 extend beyond the frame 24 into the central opening 25. In one container engaged position, the corner casting pins 72 preferably extend from the frame 24 into the central opening 25 and into the lower corner castings 12b (only two shown in Fig. 4) of the container 12, which are located in standard locations proximate to the bottom of the sides at the corners of ISO containers. Each pin 72 is preferably operably coupled with a sensor (not shown), which senses when the weight of a container 12 is on the respective pin 72. The pins 72 can be rotatable shear keys similar to the shear keys 64 in the twist lock 50 to lock the pins 72 into the lower comer castings 12b, or the pins 72 are, more preferably, merely straight members that do not lock with the corner casting 12a, 12b, but are merely inserted into one of the side openings of comer castings 12a, 12b or below the comer castings 12a, 12b.

[0041] Referring again to Fig. 3, the frame 24 includes at least one, and preferably four, container sensors 80 (only two are shown), which are mounted on the frame 24 facing inwardly toward the opening 25. Each sensor 80 preferably detects when a container 12 passes by the sensor 80. The container sensors 80 preferably are light beam operated, and, more preferably, infra-red light beam operated. However, the container sensors 80 can be a spring loaded switch, proximity detector or other type of sensors suitable for detecting when the container 12 passes by the sensors 80. The container sensors 80 preferably are located and configured to sense when the corner castings 12a, 12b are aligned with the comer casting pins 72 and may be operatively connected with actuators moving the corner casting pins 72 to engage the corner casting pins 72 with the corner castings 12a, 12b. Although four sensors 80 are preferred, more or less than four sensors 80 can be used. In addition, one or more of the sensors 80 may track certain or all of the containers 12 based on their inventory, detect contents of random containers 12 or each container 12 for various product or substances, such as detection of uranium, explosives, metallic materials, firearms, illegal drugs or narcotics (defense work), sense or survey the amount of heat radiating from each container 12, or detect the weight, fullness or center of mass of each container 12, for example. [0042] The operation of or method of employing the elevator 10 to raise laterally-adjacent containers 12 from a container ship S will now be discussed. The crane 13 may be located on the ship S to which the frame 24 is lowered, on another adjacent ship, or on an adjacent shore-based location, such as a pier or a dock. The hatch to a selected cell 6 or to two laterally-adjacent cells 16 is opened, allowing vertical access to the cell(s) 16 from the weather deck. Unless the corner casting pins 72 are already retracted, the pins 72 are moved into the container disengaged position, such that the corner casting pins 72 are retracted into the respective recess 74 in the frame 24 so that no part of or no significant part of the corner casting pins 72 extend beyond the frame 24 into the central opening 25. The spreader bar 26 is lowered to the frame 24 by the crane 13 so that the twist locks 28 on the spreader bar 26 engage a suitable connection preferably on a top surface of the trolley 17 and/or frame 24 (see Fig. 4). The spreader bar 26 is then locked onto the trolley 17 and frame 24, which can then be lifted by the crane (see Fig. 4). The frame 24 is moved from its existing location and lowered to the desired cell(s) 16 by the crane/spreader bar combination, such that the frame 24 generally surrounds the cell mouth 18 at the hatch opening 14 of two laterally- adjacent cells 16 (see Fig. 5). When the frame 24 is properly located, the frame 24 is released from the spreader bar 26 so that the frame 24 is releasably mounted (i.e. rests) in the mouth 18 over the desired cells 16 (Fig. 6).

[0043] To remove a top or first container 12' from one of the cells 16, the hoists 30 must lower the lifting frame 47 to the top surface of the first container 12' (see Fig. 6). The following description will describe the operation of only one hoist 30 located on the trolley 17, but pertains to each of the hoists 30 located on the trolley 17 or other portion of the frame 24.

[0044] The winch motor 42 is energized, rotating the winch reel 44 to play out or release the winch cable 46. The winch cable 46 is extended or played out until the twist lock 50 on the lifting frame 47 reaches the top of the first container 12'. At this point, the twist lock 50 shear key 68 contacts the corner casting 12a in the top of the first container 12'. The sensor 66 on the twist lock 50 sends a signal to the winch motor 42 to let out a relatively small amount of additional winch cable 46 to give the twist lock 0 enough slack for the shear key 68 to enter the corner casting 12a. When the sensor 66 detects that the twist lock 50 has entered the corner casting 12a, the sensor 66 sends a signal to stop the winch motor 42. Additionally, the sensor 66 sends a signal to the twist lock hydraulic system (not shown) to activate the hydraulic system to rotate and engage the shear key 64 of the twist lock 50 with the container upper corner casting 12a in a manner which is well known in the art. If the sensor 66 senses that the twist lock 50 is not properly engaged with the shear key 68 located within the container upper corner casting 12a, the sensor 66 activates a jogging mechanism (not shown) proximate or within the twist lock 50 to jog or adjust the twist lock 50 to nest the shear key 64 in the container upper corner casting 12a prior to sending a signal to rotate and engage the shear key 64 in the container upper corner casting 12a. Following the above procedure, the hoist 30 is releasably connected to the first container 12'.

[0045] When all four twist locks 50 are engaged with their respective upper corner castings 12a, the winch motors 42 are operated in a reverse direction, rotating the winch reels 44 to reel in the winch cables 46. The reeling in of the winch cables 46 lifts the twist locks 50 and first container 12' upwardly toward the hatch opening 14, transferring the first container 12' from within the respective cell 16 to the frame 24 located at the top of the respective cell 16 (see Fig. 7).

[0046] Referring to Figs. 6 and 7, the first container 12' is then lifted by the hoists 30 from the respective cell 16 at least slightly past or above the hatch opening 14 preferably until the container sensor(s) 80 senses that the lower corner castings 12b are aligned with the corner casting pins 72. Each container sensor 80 sends a signal to stop the proximal winch reel 44 and to extend the proximal corner casting pins 72 from the container disengaged position in the frame 24 to the container engaged position, extending inwardly into the central opening 25 of the frame 24, locking each of the corner casting pins 72 into the container engaged position in a respective lower corner casting 12b of the first container 12'. After the corner casting pins 72 have fully extended into their respective lower corner castings 12b, the winch motor 42 again reverses to play out or extend a sufficient amount of winch cable 46 to settle the weight of the first container 12' onto the corner casting pins 72. Alternatively, instead of locking the corner casting pins 72 into the lower corner castings 12b, the first container 12' can be lifted sufficiently above the corner casting pins 72 so that the bottom of the container 12 is above the comer casting pins 72. The corner casting pins 72 are then extended from the frame 24, and the first container 12' is then lowered on top of the corner casting pins 72. Such an alternative method eliminates the need to exactly align the lower corner castings 12b with the corner casting pins 72.

[0047] Once the first container 12' is supported by the corner casting pins 72, the sensors in the pins 72 sense that the weight of the first container 12' is on the pins 72 and send a signal to the twist lock hydraulic system to disengage the shear keys 64 of the twist locks 50 from each upper corner casting 12a. After the twist lock 50 has disengaged from the upper corner casting 12a, the winch motor 42 activates to reel in a sufficient amount of winch cable 46 to fully raise the twist lock 50 above the top of the first container 12'.

[0048] Next, it is preferred that the trolley 17 moves laterally across the top of the frame 24 to expose the top of the first container 12' (Fig. 8). In this position, the trolley 17 is preferably positioned directly above a second container 12" located in a cell 16 preferably laterally-adjacent to the cell 16 originally holding the first container 12'. The spreader bar 26 can be lowered by the crane 13 onto the top of the first container 12'. The spreader bar 26 is connected to the first container 12' by engaging the twist locks 28 with the upper corner castings 12a, as is known in the art. After the spreader bar 26 is fully connected (at all four corners) to the first container 12' (Fig. 9), the crane 13 lifts the spreader bar 26 and the first container 12' from the frame 24 sufficiently to lift the weight of the first container 12' from the corner casting pins 72, which are then retracted into the frame 24 to the container disengaged position. The first container 12' is then lifted up and away from the frame 24 by the crane/spreader bar combination for placement in a remote location (see Figs. 10 and 11). In an alternative embodiment of the corner casting pins 72, such as where the pins 72 are pivotably biased, the pins 72 are not required to retract into the frame 24.

[0049] While the first container 12' is being transported from the frame 24 to the remote location (see Fig. 10), the lifting and removal process can be repeated with the second container 12", as shown in Figs. 8- 10, which was stacked generally adjacent or next to the first container 12' within a separate, laterally-adjacent cell 16. Once the second container 12" has been raised at least slightly past or above the hatch opening 14 (see Fig. 11), corner casting pins 72 may support the second container 12" (as described above with respect to the first container 12'). At this point, the twist locks 50 of the lifting frame 47 of the second container 12" may disengage from the second container 12", and the trolley 17 moves laterally across the top of the frame 24 back above the cell 16 that previously contained the first container 12' (see Fig. 11). The lifting frame 47 may once again be lowered to attached to and lift a third container 12"'. Meanwhile, the spreader bar 26 may engage and lift the second container 12" through and above the frame 24 to the remote location (Fig. 12). The above process can be repeated until all of the desired containers 12 are removed from the ship S. When all of the containers 12 to be unloaded have been removed from the laterally-adjacent cells 16, the frame 24 can be transported by the spreader bar 26 to another pair of cells 16 to repeat the removal process, or new containers can be loaded into the cells 16 generally in a manner reverse to that described above. Alternatively, a preferred method of operation consists of unloading containers 12 from one cell and simultaneously loading containers 12 into an adjacent cell (a.k.a. "two way moves"). Such a simultaneous loading/unloading process is more efficient than unloading the entire ship S and then reloading the entire ship S. In addition, such a simultaneous

loading/unloading process helps to keep the ship S balanced in the water, so that the ship S doesn't unnecessarily list or roll and make operation of the elevator 10 more difficult. [0050] In simulations comparing the rate of raising or lowering containers 12 from a ship S based on a crane 13 that operates with the elevator 10 of the present invention and a crane 13 that operates without the elevator 10 of the present invention, the assignee of the present invention estimates that the modular elevator 10 described herein is able to increase the number of containers 12 that can be raised or lowered by approximately eight to ten and a half containers 12 per hour. Specifically, it takes approximately seventy-nine minutes to unload a hatch opening 14 of sixty-four containers (8 x 8 as shown in Fig. 2) with the elevator 10 of the present invention, as compared to approximately one hundred minutes to unload the same hatch without the elevator 10. Further, it takes approximately one minute and twelve seconds to unload one container 12 with the elevator 10 of the present invention, as compared to approximately one minute and thirty six seconds to unload the same container 12 without the elevator 10.

[0051] Further, it is a significant advantage to have the lifting frame 47 aligned with the cells 16, as in the preferred embodiment of the present invention, as opposed to aligning the spreader bar 26 by the operator of the crane 13, as is done in conventional systems. Specifically, the structure and connection of the lifting frame 47 and frame 24 of the elevator 10 assure that the lifting frame 47 is generally properly positioned (both vertically and horizontally or laterally) over the respective pair of cells 16. As a result, less time is wasted by an operator prior to beginning the loading and/or unloading process of the containers 12. In addition, the stmcture and connection of the lifting frame 47 and frame 24 of the elevator 10 reduce the likelihood that human error will slow or disrupt the loading and/or unloading process.

[0052] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.