GB2166411A - Lifting device - Google Patents

Abstract

In a lifting device for transferring goods 22 between a quay 10 and a vessel 11 by means of a horizontal two-armed overhead crane 19, which is symmetrically rotatable around a column 20 each arm section having an outrigger trolley 18a, 18b, which is movable along the arm and has lifting means 17a, 17b, column 20 is rotatable about an axis 25, which is offset from the axis of rotation 21 of the overhead crane 19 on the column 20. Thus the axis of rotation 21 can be moved towards the adjacent quay 10, for operation or away therefrom for stowage. <IMAGE>

Description

SPECIFICATION Lifting device The present invention relates to a lifting device and more particularly to a device for transferring goods between a quay and a vessel (or vice versa) by means of a horizontal, two-armed overhead crane, which is symmetrically rotatable about a column and at each arm section comprises an outrigger trolley moveable along the arm and having lifting means.

Overhead crane devices of this kind are normally used on ships equipped for the transport of goods to or from harbours that lack effective equipment for handling of goods.

A ship equipped with several of these lifting devices located along the railing can be loaded or unloaded in considerably shorter time than a ship equipped with the same number of conventional cranes. The explanation is that the lifting means one one end of the overhead crane can be loaded, while the lifting means on the other end of the crane is simultaneously unloaded.

It is, for several reasons, difficult to design a lifting device of this kind, which can fulfil all requirements regarding having a large load capacity, or taking up little space in stowed position, or having a long reach over the side of the ship and not being complicated or unreliable while being able to move rapidly between each working position. For reasons related to the technical installation the base of the overhead crane must be located at a certain distance from the railing of the vessel, which results in a reduction of the possible reach over the railing. The overhead crane must also be stowable in a position well inside of said railing, so that no part protrudes outside of this railing.

A prior art lifting device comprises an overhead crane arm, which can be displaced lengthwise, as well as rotated in relation to the carrying column.

This concept involves having several different drive means located on the column for rotation, as well as lengthwise displacement of the overhead crane, and other drive means for manoeuvring of the lifting means located at both ends of crane arm.

The present invention seeks to provide a more simple and more reliable lifting device than the previously known cranes of this type.

According to the present invention there is provided a lifting device for transferring goods comprising an overhead crane having two substantially horizontal arm sections, the crane being rotatably mounted on a column for rotation about a first axis of rotation, wherein the column is mounted on a supporting member and is rotatable relative thereto about a second axis of rotation offset from said first axis of rotation.

Preferably each arm section has an outrigger trolley movable along the arm and having lifting means.

In a preferred embodiment of the invention both lifting means are individually and simultaneously controlled by means of driving means located near the rotation centre of the overhead crane. These means for driving each lifting means along the associated arm section include a wire-drum and a push/pull mechanism.

Four elevator wires are preferably dispensed from each wire-drum, and each is connected to one corner of a box-shaped elevator.

In a particularly advantageous embodiment of the invention, the elevator wires, dispensed from each wire-drum, are continued back from the elevator, and are connected, in pairs, to an adjusting means for compensation of elevator inclination in relation to the quay, or the vessel, so that elevator wires of opposed diagonal corners are connected.

In a further development of the invention, the adjusting means comprises a lever-arm, which is rotatably mounted on a pivot shaft, and in which the elevator wires connected in pairs are affixed at equal distance from the pivot shaft. This can be displaced in the longitudinal direction of the connected wires, so that the inclination of the elevator in transverse relation to the vessel can be adjusted by means of pivoting the lever-arm, and the inclination of the elevator in lengthwise relation to the vessel can be adjusted by means of displacement of the lever-arm.

In another embodiment of the invention the elevator wires are dispensed from each wire-drum outwards to a block sheave at the respective free end of the overhead crane, then led in paraliel back to a block sheave on the outrigger trolley, around which the wires are directed 1800 back towards the elevator, at which the wires are redirected 1800 along the overhead crane towards the adjusting means. This makes it possible to move the outrigger trolley along the associated arm section, without altering the level of the elevator in the relation to said crane.

In another advantageous embodiment of the invention, the push/pull mechanisms each comprise a piston-cylinder, which at one end is affixed to a multiple block for two pull-wires, of which one inwards pull-wire is routed between blocks near the turning axis of the overhead crane and the outrigger trolley via the multiple blocks, and one outwards pull-wire is routed between blocks near the outer end of the arm section and the outrigger trolley via the multiple block. With this arrangement a displacement of the multiple block by means of the piston-cylinder by a certain distance, will result in a multiplied displacement of the outrigger trolley.

The column can include a crank shaped part, which is rotatably mounted on a base and has a collar bearing for the rotation of the overhead crane. Alternatively the column is angled in relation to the supporting frame.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a perspective view of a ship at a quay, using a lifting device according to the invention; Figure 2 shows the lifting device in top plan view in its stowed position; Figures 3-6 show the use of the lifting device while loading a ship; Figure 7 is a diagrammatic sketch of an elevator mechanism included the lifting device; and Figure 8 diagrammatically shows the design of a push/pull mechanism for an outrigger trolley in the lifting device.

Figure 1 shows a partially open perspective view of part of a ship 11 lying at a quay 10. A twoarmed lifting device 15 is mounted on the main deck 12 of the ship, between a hatch opening 13 and the railing 14, on a column 16. The lifting device includes two elevators 17a, 17b, each hanging in an associated outrigger trolley 18a, 18b. These are displaceable along the respective arm sections.

In this Figure the horizontal overhead crane arm 19 is shown pivoted about the column 20 with a centre of rotation 21 to a transversal position in relation to the length of the ship, in which position the elevator 17a is lowered onto the quay 10 for loading of boxes 22, which are stacked on pallets 22a, and loaded into the elevator 17a by means of a fork lift truck 23.

The other elevator 17b is lowered through the hatch 13 into one of the cargo holds of the ship 11, and the pallets are unloaded from the elevator by means of a fork trolley 24. When the elevator 17a is full, and the elevator 17b is empty both elevators are hoisted, as Figure 4 shows, up to the position shown in Figure 5. Then the outrigger 18a on the quay-side of the overhead crane is moved inwards along its arm-section, and the overhead crane 19 is rotated 180 about its centre of rotation 21. Then the outrigger trolley 18b of the empty elevator 17b is displaced outwards along its arm-section to the position shown in Figure 6, in which both elevators are lowered to be loaded and unloaded, respectively. This procedure is repeated until all cargo is loaded and the procedure is reversed when the cargo hold of the ship is to be unloaded.

Figure 2 shows the lifting device turned into a stowed position in parallel with the longitudinal direction of the ship. The overhead crane 19 has thereby been turned in relation to the column 20 about the centre of rotation 21. Additionally, the column 20 has been turned in relation to its base 16 about another centre of rotation 25, which is located at a distance from the railing 14 of the ship and also from the first centre of rotation 21. This first centre of rotation 21 of the overhead crane 19 can, therefore, be displaced towards or from the railing 14, so that the reach of the overhead crane over the side of the ship can be long without having any part of it protruding over the side when in stowed position.

The column base 16 is provided with a sturdy collar bearing for the rotatable column 20, which includes inner machinery for the rotation of the column about the base 16 and for the rotation of the overhead crane 19 in relation to the column 20.

This also has an operator's cabin 26, which in the operating position of the lifting device is facing the quay 10. The column 20 is also provided with a collar bearing for the overhead crane 19.

An engine house 27 is located at the centre of the overhead crane 19 and includes two hydraulically actuated wire-drums 27a (one of these is shown in Figure 7) for hoisting and lowering of the elevator 17a, 17b. Four lifting wires 28 are dispensed from each wire-drum 27a and are routed to each of the four corners of the associated elevator via sheave blocks 29 at the outer end of the overhead crane 19 and other sheave blocks 30 on the outrigger trolley 18a, 18b. Elevator blocks 31 are further located on the outrigger trolley and on the elevator. The lifting wires 28 are routed back from these elevator blocks 31 towards the engine house 27 where the wires 28 are connected in pairs to an adjusting mechansim 32.It comprises four sheave blocks 33, which direct the two wires 28 from one side of the elevator towards the two wires from the other side of the elevator, and they are affixed on a two-armed lever-arm 35, at equal distance from its pivot shaft 34, which is displaceable in the longitudinal direction of the attached wires, between the blocks 33. The diagonally opposed corners of the elevator are attached on each side of the pivot shaft 34, which means that a pivoting of the leverarm 35 by means of a piston-cylinder 36 in any direction will result in one of the elevator's long sides being raised and the opposite side being lowered, which makes it possible to compensate for inclination in transverse relation to the ship.A displacement of the pivot point 34 of the lever-arm 35 between the blocks 33, by means of the pistoncylinder 37, will result in one of the elevator's short sides being raised and the opposite side being lowered, which makes it possible to compensate for inclination in lengthwise relation to the ship.

The outrigger trolleys 18a, 18b can be moved outwards or inwards along the overhead crane 19, without altering the level of the elevator 17a, 17b in relation to the crane. This is possible because the parts of the wires 28 running between the fixed points in the overhead crane 19; the blocks 29 and the adjusting mechanism 32, are turned 1800 around the block sheaves 30, so that the length of these wire parts will remain constant while the outrigger trolleys are moved outwards, or inwards along the overhead crane.

The operation of the outrigger trolleys is effected by means of a piston-cylinder 38 for each trolley.

This piston- cylinder 38 is at one end affixed to a bracket in the crane 19 and at the other end affixed to a multiple block 39. Corresponding blocks are fixed on inner and outer positions on the overhead crane 19 and an inwards pull wire 41 runs from a fastener on the multiple block 39 to a block 40 at the inner end of the crane and back to the multiple block 39, back to a block 40 at the inner end of the crane and out to a fastener 42 in the outrigger trolley 18a, 18b. When the piston-cylinder 38 presses the multiple block 39 outwards, the outrigger trolley will be pulled inwards a distance corresponding to the distance of movement of the piston-cylinder 38 multiplied by the number of wire-parts stretching between the inner end of the crane and the multiple block 39. In the same way a outwards pull wire 43 runs between the multiple block 39, blocks 40 at the outer end of the crane and a fastening 44 on the outrigger trolley 18. In this way a propor tionally long reach is achieved for the outrigger trolley's movement with only a short working stroke of the piston-cylinder 38.

The entire lifting device can be operated by hydraulic means known for durability. Only the wiredrums 27a and the piston-cylinders 36, 37 and 38 of these hydraulic means have to be located up in the overhead crane 19, which makes the lifting device comparatively simple to service.

Various modifications may be made within the scope of the invention. It is apparent that the lifting device can be mounted on a quay or a goods terminal, e.g. for handling of railway goods, as well as on a ship. The column 20 can be inclined instead of crank-shaped as shown. Other lifting means can be used instead of the elevators 17a, 17b e.g. a container spreader.

Claims (15)

1. A lifting device for transferring goods com prising an overhead crane having two substantially horizontal arm sections, the crane being rotatably mounted on a column for rotation about a first axis of rotation, wherein the column is mounted on a supporting member and is rotatable relative thereto about a second axis of rotation offset from said first axis of rotation.

2. A device according to claim 1, wherein each arm section has an outrigger trolley movable along the arm and having lifting means.

3. A lifting device as claimed in claim 1 or 2, wherein both lifting means are individually and si multaneously controlled by means of driving means located adjacent to the first axis of rotation.

4. A lifting device as claimed in claim 3, wherein the means for driving each lifting means along the associated arm section includes a wire drum and a push-pull mechanism.

5. A lifting device as claimed in claim 4, wherein four elevator wires are dispensed from each wire-drum and each is connected to one cor ner of a box-shaped elevator.

6. A lifting device as claimed in claim 5, wherein the elevator wires dispensed from each wire-drum are continued back from the elevator and are connected in pairs, to an adjusting means for compensation of elevator inclination so that el evator wires of opposed diagonal corners are con nected.

7. A lifting device as claimed in claim 6, wherein the adjusting means comprises a two armed lever-arm which is rotatably mounted on a pivot shaft, and in which the elevator wires, which are connected in pairs are affixed at equal distance from the pivot shaft, which is displaceable in the longitudinal direction of the attached wires, so that the inclination of the elevator in a transverse rela tion to the supporting member can be adjusted by means of pivoting the lever-arm, and the inclina tion of the elevator in longitudinal relation to the supporting member can be adjusted by means of displacement of the lever-arm.

8. A lifting device as claimed in claim 6, wherein the elevator wires are dispensed from each wire-drum outwards to a block sheave at the respective free end of the overhead crane, in parallel back to a block sheave on the outrigger trolley, around which the wires are directed 180 back towards the elevator, at which the wires are redirected 180 along the overhead crane towards the adjusting means, so that the outrigger trolley can be moved along the arm section, without altering the level of the elevator in relation to the arm.

9. A lifting device as claimed in claim 4, wherein the push/pull mechanism, comprises a piston-cylinder which at one end is affixed in a bracket in the crane and the other end is affixed to a multiple block for two pull-wires, of which one inwards pull-wire is routed between blocks adjacent to the first axis of rotation, and the outrigger trolley via the multiple block, and one outwards pull-wire is routed between blocks near the outer end of the arm section and the outrigger trolley via the multiple block, so that a displacement of the multiple block by means of the piston-cylinder by a certain distance, will result in a larger displacement of the outrigger trolley.

10. A lifting device as claimed in any preceding claim, wherein the column includes a crank shaped part, which is rotatably mounted on a base and has a collar bearing for the rotation of the overhead crane.

11. A lifting device as claimed in any one of claims 1 to 9, wherein the column is angled in relation to the supporting member.

12. A lifting device as claimed in any preceding claim wherein the supporting member is a vessel.

13. A lifting device as claimed in any of claims 1 to 11, wherein the supporting member is a quay.

14. A lifting device substantially as herein described with reference to the accompanying drawings.

15. As an independent invention the additional feature of any of claims 2 to 11.