GB2041885A - Method of Stacking Containers - Google Patents

Abstract

A method of supporting and stacking containers comprises raising a first container (50) on an elevator, securing the container in a raised position by means of supports, lowering the elevator, raising a second container (53) on the elevator such that the base of the first container (50) is supported by the top of the second container and releasing the securement of the first container. The elevator may then be raised again and the second container (53) secured by the supports. The elevator can then be lowered clear of the second container. Apparatus for performing the method comprises two supports spaced apart to opposite sides of a container receiving location. Container engagement means are provided on each of the supports which are adjusted for engagement with a container and are capable of supporting the container upon removal of the elevator. Each container engagement means comprises a container engagement member mounted on a support arm which in turn is movably mounted on an associated support. <IMAGE>

Description

SPECIFICATION Method of and Apparatus for Supporting and Stacking of Containers This invention relatives to a support apparatus for supporting containers and to a method of stacking containers.

The invention has been arrived at from a consideration of the requirements of transport of goods containers such as are employed in shipping. Many "container" ships have a trailer deck beneath the weather deck which permits a trailer vehicle carrying a container to be driven directly thereon and unloaded. Such ships are termed "roll on - roll off" ships. Some such ships employ an elevator capable of carrying containers, between trailer and weather decks and often the height available between the decks is insufficient to permit containers to be stacked one on top of another on a vehicle or elevator platform on the trailer deck. If it is desired to stack containers on the weather deck or on the elevator when raised to deck level then the weather deck must be sufficiently strong to carry the concentrated loads of container carrying forklift trucks.

The Invention seeks to provide a method of stacking and a support apparatus for enabling the stacking to be carried out which facilitates stacking of containers and which can if required be used in a ship to permit stacking at weather deck level without requiring strengthening of the weather deck.

According to a first aspect of the invention there is provided a method of stacking containers comprising raising a first container on an elevator, securing the container in a raised position, lowering the elevator, raising a second container on the elevator such that the base of the first container is supported by the top of the second container and releasing the securement of the first container.

The elevator may be raised again to enable the second container to be secured in the raised position thereby permitting lowering of the elevator and raising of a third container on the elevator such that the base of the second container is supported by the top of the third container.

According to a second aspect of the invention there is provided a container engagement apparatus comprising a support and a container engagement member mounted on the support and movable laterally thereof for engagement with and disengagement from a container.

The support may comprise a support arm carrying the engagement member. The support may comprise a pedestal adapted for mounting on a surface and with the support arm mounted thereon or may comprise a fork-lift truck mast with spreader and with the support arm mounted thereon. The support arm may be movable laterally of the pedestal or mast to effect said lateral movement of the engagement member.

The support arm may be pivotally mounted on the pedestal or spreader to enable movement between a horizontal supporting disposition for use and a raised position when not in use.

According to a third aspect of the invention there is provided a container support apparatus comprising first and second support means spaced apart to opposite sides of a container receiving location, engagement means on each support means adapted for engagement with a container when located on a support at the receiving location and capable of supporting the container upon removal of the support.

The first and second support means may each comprise a container engagement apparatus as previousiy defined. A plurality of such container engagement apparatus may be provided on each of said opposite sides of the receiving location.

Preferably the container engagement apparatus is located so as to permit engagement with the container at or near opposite ends.

The apparatus may include an elevator platform for carrying a container and for moving the container into the receiving location. Means may be provided for detecting when a container is located on the platform in a position which will be suitable for engagement by the engagement means when the platform is raised to the receiving location.

In order that the invention and its various other preferred features may be understood more easily, embodiments thereof will now be described, by way of example only, with reference to the drawings, in which: Figure 1 is a schematic side view of a container engagement apparatus constructed in accordance with the invention; Figure 2 is a plan view showing the end of the support arm of the apparatus of Figure 1; Figure 3 shows in end view a container supported by the container support apparatus; Figure 4 is a plan view of a container supported by the container support apparatus; Figure 5 is a side view showing a container supported by the container support apparatus and a second container or a trailer on an elevator platform awaiting stacking;; Figures 6 to 11 are schematic views showing a container support apparatus constructed in accordance with the invention showing sequentially the stacking capability and illustrating a method of stacking in accordance with the invention; The container engagement apparatus of Figure 1 comprises a pedestal 20 adapted for mounting on the weather deck of a ship by means of a flange 21. The pedestal is recessed at the top to receive one end of a support arm 22. The support arm 22 has a curved guide slot 23 at the pedestal end and is retained in the recess in the pedestal by means of an axle 24 which extends across the recess through the slot 23 and is secured to the pedestal at opposite sides of the recess. The axle permits pivotal movement of the arm on the pedestal and lateral movement of the arm relative to the pedestal.The pedestal is provided with one or more rollers 25 for supporting the arm and facilitating lateral movement. A stop 26 on the pedestal locates in an elongate slot 27 in the arm and upon backward lateral movement when the stop engages the end of the recess it initiates pivotal movement of the arm in an upward direction. The arm movement is effected by a ram 28 in response to hydraulic or pneumatic pressure. The ram is pivotally mounted at one end on the axle 24 and at the other end on the arm 22.

At the end of the support arm 22 remote from the pedestal a carrier arm 30 is pivotally mounted by one end and extends downwardly. A second ram 31 operable by hydraulic or pneumatic pressure is pivotally coupled at one end to a position part way along the carrier arm 30 and at the other end to the support arm 22 and serves to pivot the arm 30 between an operative position substantially perpendicular to the support arm and a non-operative position where it is disposed at an acute angle to the support arm. The support arm presses against a container engagement member in the form of a shaped rod 32 which is free to slide against the side of the arm remote from the pedestal and is shown in engagement with a socket 33 of a container 34.

The shaped rod 32 has one end of a chain 35 connected thereto. The other end of the chain is coupled with a locking pin 36 (see Figure 2) which is engageable with a locking latch 37 at the end of the support arm 22. The rod and chain support the weight of the container.

A platform 38 is povitally mounted at one side on the pedestal 20 by means of a pivot 40 and at the other side is connected to the support arm 22 by means of ties 41 which are pivotally coupled at one end to the end of the platform remote from the pivot 40 and at the other end to the support arm 22 at a position near to the end remote from the pedestal. The platform moves, upon raising of the support arm, from a substantially horizontal position to an upwardly extending storage position. In the horizontal position the platform can be stood on by an operator during engagement of the rod 32 and locking pin 36.

The raised or storage position is shown in Figure 1 in broken lines whilst the operative position is shown in solid lines. As can be seen a locking arrangement 42 is provided for securing the arm 22 in the raised storage position.

In use when a container such as 34 is situated in position, in readiness to be supported, the lock 42 is released and the rams 28 and 31 are extended by application of fluid pressure whereupon the arm 32 is pivoted downwardly into the horizontal position and the carrier arm 30 is pivoted into the vertical position. The ram 28 continues to extend until the rod 32 is close enough to engage with the socket 33 and this position is sensed by means of a sensor 43 which contacts the side of the container. The sensor is effective to cut off the feed of pressure fluid to the ram 28. The operation engaged rod 32 in the socket 33 with a quarter rotary movement as is normal in container handling practice.

The container engagement apparatus of Figure 1 is usable in a container support apparatus such as is iliustrated in Figures 3, 4 and 5. In this apparatus which is suitable for use with 20 foot or 40 foot long containers three such container engagement apparatus are used on each of two opposite sides and are herein designated 45. The container engagement apparatus 45 are spaced apart for engagement with opposite ends of a container and in the case illustrated where a 40 foot container is to be supported the centre container engagement apparatus is not here being used and is shown in its raised position. To support a 20 foot container the centre container engagement apparatus and the container engagement apparatus to one side thereof are used.

In use a trailer is driven onto the hoistable platform. Its lateral location is ensured by painting guide lines on the platform and tests have shown that drivers can follows these with an accuracy within 5 cm. The longitudinal location is controlled by photocells 46 operating a signal light 47 in the drivers field of view.

The operation can be seen in schematic illustration in Figures 6 to 11 and will now be described. In Figure 6 a first container 50 mounted on a low loading trailer 51 e.g. a MAFI trailer has been driven into position on a hoistable platform 52.

The hoistable pTatform is now raised to the position shown in Figure 7 and then the arms 22 are lowered which results in the folding platform 38 (see Figure 1) being lowered. An operator stands on the platform and engages the shaped rods 32 (see Figure 1) with the sockets provided in the corner castings of the container. The istable platform 52 is now lowered, the empty trailer is removed and a second container 53 on a trailer is driven onto the platform as illustrated in Figure 8. The platform is now partly raised and the laterial position of the support arms 22 are adjusted by fluid pressure to the rams 28 so that the two containers are positioned accurately one on top of another and can be linked together by twistlocks see Figure 9. The operator again uses the platform 38 whilst doing this. The support arms 22 can now be swung away as shown in Figure 10 and the platform can be raised to upper deck level and the trailer can be towed away as in Figure 11.

Alternatively when raised to upper deck level the lower container can be supported by the arms 22 by engagement of the shaped rods on the arms 30 with sockets in the corner castings of the container and a further container can be raised by the platform 52 to produce a stack of three containers. For discharging the sequence is reversed.

Instead of the pedestal 20 a fork lift truck mast with spreader and with the support arm 22 mounted thereon may be employed.

The sequence using such forklift truck masts and spreaders is similar to that previously described and will not be described in detail.

In some cases the hoistable platform will have insufficient capacity to carry two fully loaded containers (two 20 feet - 20 ton or two 40 feet 30 ton). The attachment can still be of value, as the upper container can be an empty one, or one whose weight is limited by volume cargo. It has been suggested that in some trades where there is an imbalance of cargo -- containerised cargo in one direction and break bulk in the reverse attachment could be used to load empty containers two or three high on the weather deck, leaving the trailer deck free for cargos such as fruit or vegetables.

Claims (14)

Claims

1. A method of stacking containers comprising raising a first container on an elevator, securing the container in a raised position, lowering the elevator, raising a second container on the elevator such that the base of the first container is supported by the top of the second container and releasing the securement of the first container.

2. A method according to claim 1, wherein after said first container is released, the elevator is raised again and the second container is secured in the raised position.

3. A method according to claim 1, wherein after said second container has been secured in the raised position, the elevator is lowered, and a third container is raised on the elevator such that the base of the second container is supported by the top of the third container.

4. A container engagement apparatus comprising a support and a container engagement member mounted on the support and movable laterally for engagement with and disengagement from a container.

5. An apparatus according to claim 4, wherein the support comprises a support arm carrying the engagement member.

6. An apparatus according to claim 5, wherein the support arm is mounted for lateral movement to effect said lateral movement of the engagement member.

7. An apparatus according to claim 5, wherein the support arm is pivotally mounted to enable movement between a substantially horizontal supporting disposition for use and a raised position when not in use.

8. An apparatus according to any one of claims 5 to 7 wherein the support further includes a pedestal adapted for mounting on a surface and with the support arm mounted thereon.

9. An apparatus according to any one of claims 5 to 7, wherein the support further includes a forklift truck mast with spreader and with the support arm mounted thereon.

10. A container support apparatus comprising first and second support means spaced apart to opposite sides of a container receiving location, engagement means being provided on each support means adapted for engagement with a container when located on a support at the receiving location and capable of supporting the container upon removal of the support.

11. A container support apparatus according to claim 10, wherein the first and second support means each comprise a container engagement apparatus claimed in any one of claims 4 to 9.

12. A container support apparatus according to claim 11 wherein a plurality of said container engagement apparatus are provided on each of said opposite sides of the receiving location.

1 3. A container support apparatus according to claim 12, wherein the container engagement apparatus is located so as to permit engagement with the container at or near opposite ends thereof.

14. A container support apparatus according to any one of claims 10 to 12, wherein the apparatus further includes an elevator platform for carrying a container and for moving the container into the receiving location.

1 5. A container support apparatus according to claim 14, wherein means are provided for detecting when a container is located on the platform in a position switchable for engagement by the engagement means when the platform is moved to the receiving location.

1 6. A method of stacking containers substantially as described herein with reference to the drawings.

1 7. A container engagement apparatus substantially as described herein with reference to Figs. 1 and 2 of the drawings.

1 8. A container support apparatus substantially as described herein with reference to Figs. 3 to 11 of the drawings.