Hoisting device and method for use thereof

Abstract

Hoisting device 1 for lifting a load 2 comprises a lower hoisting frame 3 which is mounted on an upper hoisting frame 4. The hoisting device 1 is provided with means 6 for suspending it from a set of hoisting cables 5, which suspending means 6 are arranged on the upper hoisting frame 4 in the shown example. In addition, hoisting device 1 is provided with take-up means 7 for taking up the load 2, which load take-up means 7 comprise in the shown example a number of take-up elements 9 which are arranged on the underside of the lower hoisting frame 3, at the corners thereof. In the shown example the suspending means 6 comprise two pairs of cable sheaves 8 which are each arranged at an end of the upper hoisting frame 4. The invention further relates to a method for placing a hoisting device suspended from hoisting cables or a load carried by it, at a desired position.

Description

[0001] HOISTING DEVICE AND METHOD FOR USE THEREOF

[0002] The invention relates to a hoisting device, comprising means arranged on an upper side thereof for suspending the hoisting device from at least two hoisting cables, which are suspended at a mutual distance from a hoisting installation in a longitudinal direction of the hoisting device, and means arranged on an underside thereof for taking up a load. Such a hoisting device is generally known and is for instance used in transfer of containers in ports.

[0003] The known hoisting device is provided with two cable sheaves or two pairs of cable sheaves, which are generally arranged close to two outer ends of an upper part or central part of the hoisting device. The known hoisting device is further provided with take-up elements or twistlocks which are arranged on the underside of the frame, at corners thereof. The known hoisting device is known as container spreader. Variants are known wherein the hoisting device consists of an upper hoisting frame, referred to as headblock, and a lower hoisting frame mounted thereon and forming the spreader. In that case the cable sheaves are arranged at the outer ends of the headblock, while the twistlocks are arranged at the corners of the spreader.

[0004] The known hoisting device is suspended from a hoisting installation, for instance a port crane for transfer of containers between ships and the quay, referred to as STS (Ship-To-Shore). Such an STS port crane or container crane generally comprises a gantry located on the quay and carrying an outrigger or arm which extends to a position above a hold of a container ship moored at the quay. Movable along this arm is a trolley which carries the cable sheaves along which the hoisting cables are run from a reel on the crane to the hoisting device.

[0005] When transferring containers by means of container cranes, the cycle time is an important factor. The downtime of container ships in ports for transfer of containers is ideally kept a short as possible. For this purpose the hoisting and paying-out speeds of the hoisting installation and the travel speed of the trolley of the container crane, among other things, are usually increased as far as possible. Additionally, container cranes are increasingly being provided with sensors to detect the positions of containers and cells in the hold of ships increasingly accurately. This allows cranes to (automatically) position their spreaders increasingly accurately. Accurate positioning is important since the clearance between containers and the cell guiding on board ships or between containers on trailers on land is very small.

[0006] Since the hoisting device hangs from relatively long hoisting cables, there are always factors that impede accurate positioning above another container, a trailer or a cell in the hold of a container ship, such as wind and the mass of a container. In addition, the long hoisting cables delay corrections on the positioning which are implemented from the crane. This means that when for instance a spreader with container reaches a position directly above a ship’s cell, the hoisting installation is often unable to pay out directly to lower the container into the cell. Correction is thennecessary first - often only in the direction of travel of the trolley - in order to end up perfectly above the cell and to be able to continue paying out.

[0007] Methods are known for correcting the position from the crane, for instance by means of moving the trolley or by making use of a Trim, List, Skew (TLS) System, but these are often inaccurate or slow. Because the correction is implemented from the crane or trolley, the period of pendulum of the mass - hoisting device and container - on the hoisting cables, which has an additional delaying effect, must therefore be taken into consideration.

[0008] The invention has for its object to provide a hoisting device wherein these drawbacks do not occur, or do so to lesser extent. This is achieved in a hoisting device of the above described type in that arranged between the suspending means and the load take-up means are controllable means for making at least a part of the hoisting device pivot about a horizontal longitudinal axis, wherein the horizontal longitudinal axis extends substantially through a centre of gravity of the hoisting device and a load optionally taken up thereby. Such a pivoting movement results in a small yet rapid displacement in horizontal direction of the outermost contours of the hoisting device and a load optionally taken up thereby.

[0009] The centre of gravity of the hoisting device and optional load is here in principle not displaced in horizontal direction. This is because there is no external reaction force in horizontal direction because the hoisting device with its optional load is suspended freely from the hoisting cables, these running vertically from the crane. All movements thus take place about the centre of gravity, which remains stationary in principle. The horizontal displacement of the outermost contours of the hoisting device and the optional load is thus formed by the horizontal component of the pivoting movement about the centre of gravity. Performing the correction directly in the hoisting frame itself makes it possible to react quickly to detected deviations in the position.

[0010] In an embodiment of the hoisting device the suspending means are arranged at or close to ends of an upper part of the hoisting device, the load take-up means comprise take-up elements arranged at or close to corners of a lower part of the hoisting device, and the controllable pivoting means comprise at least one pivot bearing arranged between the suspending means and the take-up elements. By making use of a physical pivot bearing vertical loads resulting from the mass of the hoisting device and the load taken up thereby are transmitted through this pivot bearing. The pivoting movement can then be initiated by merely exerting a torque around this pivot bearing.

[0011] In an embodiment the suspending means are incorporated in an upper hoisting frame and the load take-up means are incorporated in a lower hoisting frame, which is mounted pivotally on the upper hoisting frame via the at least one pivot bearing. The pivoting movement can thus be realized at a central location inside the hoisting device.

[0012] The controllable pivoting means can here then comprise a mounting member for the upper hoisting frame which is arranged on an upper side of the lower hoisting frame and is bearing-mounted pivotally in the lower hoisting frame, as well as an actuator arranged between the lower hoisting frame and the mounting member. The mounting member - and thereby the upper hoisting frame - can be pivoted or tilted relative to the lower hoisting frame by controlling the actuator. By incorporating the controllable pivoting means in the lower hoisting frame it can also be used without upper hoisting frame, if desired.

[0013] In another embodiment the suspending means comprise cable sheaves around which the hoisting cables are trained, and the load take-up means are incorporated in a hoisting frame which is suspended pivotally from the cable sheaves via the at least one pivot bearing. The pivoting movement can thus be realized at the top of the hoisting device, between the cable sheaves and the frame carrying the load. This frame can then be a spreader, which is suspended directly from the cable sheaves, but it is also possible to envisage the frame being formed by a combination of headblock and spreader, wherein the headblock is suspended from the cable sheaves.

[0014] The controllable pivoting means can here then comprise a bearing member for the cable sheaves which is arranged on an upper side of the hoisting frame and is bearing-mounted pivotally in the hoisting frame, as well as an actuator arranged between the hoisting frame and the bearing member. The bearing member - and thereby the cable sheave or sheaves - can be pivoted or tilted relative to the hoisting frame by controlling the actuator.

[0015] In an embodiment the controllable pivoting means can comprise a control connected to the actuator. With such a control the correction can also be performed automatically.

[0016] In another embodiment the controllable pivoting means can comprise a position sensor connected to the control. In this way the correction can be started without intervention by a human operator.

[0017] In yet another embodiment the control is configured to control the actuator initially in a first direction and, after a turning point has been reached, to control the actuator in a second direction opposite thereto. A pivoting movement can thus be brought about first in order to cause a horizontal displacement of the outer contour, and the hoisting device with optional load can subsequently be returned to the starting position again, for instance in order to lower a container further into a ship's hold along a cell guide.

[0018] The turning point can be determined here by a duration set by the control or a movement performed by the actuator. The correction can thus be performed for a determined amount of time or over a determined distance.

[0019] On the other hand, it is also possible for the turning point to (also) be determined by a detection by the position sensor. The pivoting movement can thus be undone when the sensor determines that the position has indeed been corrected.

[0020] In an embodiment the upper hoisting frame comprises a headblock, while the lower hoisting frame comprises a spreader.The suspending means can here comprise cable sheaves around which the hoisting cables are trained, and the load take-up means can comprise twistlocks.

[0021] In another embodiment the suspending means can comprise a plurality of pairs of cable sheaves and the controllable pivoting means can be configured to displace one of the cable sheaves of each pair relative to the other cable sheave. Displacing the two adjacent cable sheaves relative to each other likewise results in a pivoting movement of the hoisting device and its optional load. Because the pivoting movement is generated in this variant by a vertical displacement of one of the cable sheaves of each pair, a considerable load is exerted on the hoisting device here, and the centre of gravity will be displaced in vertical direction. This movement thereby requires more power than the pivoting movement about the centre of gravity of the hoisting device and its optional load. This variant may however be structurally simpler.

[0022] In the embodiment with pivotable mounting or bearing member, this mounting or bearing member can be situated substantially in a plane determined by one of the cable sheaves. As stated above, internal loads on the construction are minimized thereby.

[0023] The invention also relates to a method for setting down at a desired position a hoisting device suspended from hoisting cables or a load taken up thereby, this comprising the steps of paying out the hoisting cables until the hoisting device or the load is situated in the vicinity of the desired position, detecting a deviation between the position of the hoisting device or the load after paying out of the hoisting cables and the desired position, performing a correction in order to reduce or eliminate the deviation, and paying out the hoisting cables further until the hoisting device or the load is situated at the desired position. Such a method is also known, as already described above.

[0024] The method according to the invention is distinguished from the known method in that the correction is performed by making the hoisting device and the load optionally taken up thereby pivot relative to the hoisting cables about a horizontal longitudinal axis of the hoisting device which extends substantially through a centre of gravity of the hoisting device and the load optionally taken up thereby, such that an underside of the hoisting device or the load taken up thereby is displaced substantially horizontally. As elucidated above, this pivoting movement about the centre of gravity results in a small yet relatively rapid displacement in horizontal direction of the outermost contour of the hoisting device and its optional load, whereby the detected deviation is corrected quickly.

[0025] Further embodiments of the method according to the invention form the subject-matter of the dependent claims 17-23.

[0026] The invention will now be elucidated on the basis of two examples wherein reference is made to the accompanying drawing in which corresponding components are designated with reference numerals increased by 200, and in which:Fig. 1 is a perspective top view of a hoisting device according to a first embodiment of the invention and load taken up thereby after a pivoting movement has been performed,

[0027] Fig. 2 is a perspective top view from another side of a lower hoisting frame of the hoisting device of Fig. 1 ,

[0028] Fig. 3 is a schematic view of the setting down of a container in a cell, wherein the container has not been positioned entirely correctly yet,

[0029] Fig. 4 is a view corresponding with Fig. 3 of the correcting of the position of the container by a small horizontal displacement as a result of a mutual pivoting movement of two parts of the hoisting device,

[0030] Fig. 5 is a partially cut-away front view of the lower hoisting frame of Fig. 2 in a neutral position,

[0031] Fig. 6 is a view corresponding with Fig. 5 of the whole hoisting device which is suspended from hoisting cables,

[0032] Fig. 7A is a front view of the lower hoisting frame of Fig. 5 in a pivoting position, Fig. 7B is a rear view of the lower hoisting frame in the pivoting position of Fig. 7A, Fig. 8A and Fig. 8B are views corresponding with respectively Fig. 7A and Fig. 7B of the whole hoisting device which is suspended from hoisting cables,

[0033] Fig. 9 is a view corresponding with Fig. 4 of the correcting of the position of the container by a small horizontal displacement as a result of a mutual displacement of two cable sheaves of the hoisting device,

[0034] Fig. 10 is a diagram showing the different components of the hoisting device according to the first embodiment of the invention,

[0035] Fig. 11 is a schematic representation of the different steps of the method according to the invention,

[0036] Fig. 12A is a partially cut-away front view of a second embodiment of the hoisting device according to the invention in a neutral position,

[0037] Fig. 12B is a view corresponding with Fig. 12A of the hoisting device in a pivoting position, and

[0038] Fig. 13A and Fig. 13B are views corresponding with respectively Fig. 12A and Fig. 12B of the hoisting device which is suspended from hoisting cables.

[0039] In the shown example a hoisting device 1 for lifting a load 2 comprises a lower hoisting frame 3 which is mounted on an upper hoisting frame 4. The hoisting device 1 is provided with means 6 for suspending it from a set of hoisting cables 5, which suspending means 6 are arranged on the upper hoisting frame 4 in the shown example. In addition, hoisting device 1 is provided with take-up means 7 for taking up the load 2, which load take-up means 7 comprise in the shown example a number of take-up elements 9 which are arranged on the underside of the lower hoistingframe 3, at the corners thereof. In the shown example the suspending means 6 comprise two pairs of cable sheaves 8 which are each arranged at an end of the upper hoisting frame 4.

[0040] In the shown example the lower hoisting frame 3 comprises a central box 10 in which are formed two parallel channels 11 for receiving slide beams 12. By sliding the beams 12 in and out the length of the lower hoisting frame 3 can be varied so that loads 2 of different sizes can be taken up, for instance 20-foot, 30-foot and 40-foot containers. Mounted at the end of each slide beam 12 is a transverse beam or end beam 13 which carries the take-up elements 9, here in the form of twistlocks, on its outer ends. Each transverse beam or end beam 13 is further provided at its ends with one or more pivotable flippers 14.

[0041] In the shown example controllable means 22 are arranged at the ends of central box 10 in order to make the lower and upper hoisting frame 3, 4 pivot relative to each other about a horizontal axis A, whereby the hoisting device 1 pivots about its centre of gravity CG as a whole -and in the case that a load 2 is hanging under hoisting device 1 , about the centre of gravity of the combination of hoisting device and load. In this example the controllable pivoting means comprise two mounting members 23 which are each bearing-mounted pivotally in a part 24 of the lower hoisting frame 3 by means of a pivot bearing 25. The pivot bearings 25 take a robust form because they must be able to carry both the lower hoisting frame 3 and the load 2. The mounting members 23 and pivot bearings 25 are arranged at the ends of the central box 10 and thereby lie substantially in the plane of the suspending means 6 of the upper hoisting frame 4 when it is attached to the mounting members 23.

[0042] Provided for this attachment are openings 32, which can be brought into register with corresponding openings in transverse end parts 16 of the upper hoisting frame 4, after which connecting pins 35 can be arranged in the openings. In addition to comprising the two end parts 16, the upper hoisting frame 4 otherwise also comprises a central connecting part 15 here.

[0043] The controllable pivoting means 22 further comprise an actuator 33 which is connected to both the lower hoisting frame 3 and the mounting member 23. In the shown example the actuator 33 is embodied as hydraulic cylinder, which is mounted in the lower hoisting frame 3 and which has a piston rod 34 which is connected to the mounting member 23. By extending or retracting the piston rod 34 the mounting member 23 can be pivoted in two directions from the neutral position shown in Fig. 5, as can be seen in Fig. 7. Each mounting member 23 is here otherwise provided with its own actuator 33 in order to enable the pivoting movement to take place synchronously, so that the hoisting frames 3, 4 are under as little torsional stress as possible.

[0044] The hoisting device 1 is suspended from a hoisting installation 26, for instance an STS container crane, by means of the hoisting cables 5. This hoisting installation comprises a trolley 27 which is movable along an arm or outrigger 29 in the direction of arrows T. Further shown is a cab 28 from which an operator operates the crane.When hoisting device 1 with a load 2 thereon has been moved from the quay to a position above the hold of a ship (step 101 of the method 100 in Fig. 11) via lifting, moving the trolley 27 and paying out the hoisting cables 5, the position of load 2 is detected, for instance by means of one or more position sensors 37 which can be installed on hoisting device 1. This forms step 102 of method 100. When it is determined in step 103 that the position of load 2 is not yet the desired position, this position must be corrected as quickly as possible (step 104). This situation is shown in Fig. 3, where a corner 21 of the load 2 hangs above a guide 31 of a cell 30. In order to be able to lower the load 2 into the cell 30 the load must be moved slightly to the right in the figure.

[0045] This movement is realized in rapid and simple manner by pivoting the upper and lower hoisting frame 4, 3 relative to each other, whereby the hoisting device 1 and the load pivot as a whole about their shared centre of gravity CG in the direction of arrow P2. The corner 21 and the bottom 17 of load 2 are hereby displaced in horizontal direction so that corner 21 and bottom 17 of load 2 are now aligned with cell 30 (Fig. 4). By now paying out the hoisting cables 5 further (step 105) load 2 can be lowered into cell 30. The pivoting movement according to arrow Pl can simultaneously be undone by moving the actuator 30 in the opposite direction (step 106). Undoing the pivoting movement can be done after a determined amount of time, after a determined movement or on the basis of a detection by the position sensor that load 2 is in the desired position.

[0046] Instead of pivoting the hoisting frames 3, 4 relative to each other, a similar pivoting movement of hoisting device 1 and load 2 can also be achieved by for instance moving the lefthand cable sheave 8A upward relative to the right-hand cable sheave 8B (Fig. 9) in the direction of arrow V. This in turn results in a pivoting movement to the right in the drawing, indicated with arrow P2. This pivoting movement can subsequently be undone again by moving the cable sheave 8A downward along arrow V, wherein hoisting device 1 and load 2 pivot back in the direction of arrow Pl. Greater forces do occur here, relative to the other method.

[0047] In another embodiment of the hoisting device 201 according to the invention the controllable pivoting means 222 are arranged on the upper side of the upper hoisting frame 204 (Fig. 12). This upper hoisting frame 204 is in turn connected to mounting members 223 at the ends of the central box 210 of lower hoisting frame 203 by means of pins 235 in openings 232. In this example the mounting members 223 are however connected not pivotally but rigidly to the lower hoisting frame 203.

[0048] The controllable pivoting means 222 in turn comprise pivot bearings 225, which are in this case arranged in transverse end parts 216 of the upper hoisting frame 204 and which connect the upper hoisting frame 204 pivotally to bearing members 238. In each of these bearing members 238 two cable sheaves 208 are bearing-mounted rotatably about rotation shafts 239. Trained round the cable sheaves 208 are hoisting cables 205, whereby hoisting device 201 can be moved upward and downward.The controllable pivoting means 222 further once again comprise actuators 233 here, one on each side of the upper hoisting frame 204 in order to make the pivoting movement take place synchronously and to prevent torsion. In the shown example each actuator 233 is embodied as a hydraulic cylinder which is attached to the upper hoisting frame 204 and which has a piston rod 234 which is connected to the bearing member 238. By extending or retracting the piston rod 234 the bearing member 238 can be pivoted in two directions Pl, P2 from the neutral position shown in Fig. 12A and Fig. 13 A, one of which directions can be seen in Fig. 12B and Fig. 13B.

[0049] The second embodiment of hoisting device 201 shown here further corresponds with the first embodiment, and is thus also provided with slide beams 212, end beams 213, twistlocks 209 and flippers 214, components which otherwise do not play any special role for the invention.

[0050] The invention thus makes it possible to rapidly and simply correct the position of a hoisting device 1, 201 hanging exclusively from vertical hoisting cables 5, 205, which are reeved at the ends of device 1, 201 and on which no external reaction forces thus act.

[0051] Although the invention has been elucidated here on the basis of an embodiment, it can be varied in many ways within the scope of the following claims.

Claims

Claims1. Hoisting device, comprising means arranged on an upper side thereof for suspending the hoisting device from at least two hoisting cables, which are suspended at a mutual distance from a hoisting installation in a longitudinal direction of the hoisting device, and means arranged on an underside thereof for taking up a load, wherein arranged between the suspending means and the load take-up means are controllable means for making at least a part of the hoisting device pivot about a horizontal longitudinal axis, wherein the horizontal longitudinal axis extends substantially through a centre of gravity of the hoisting device and a load optionally taken up thereby.

2. Hoisting device according to claim 1 , wherein the suspending means are arranged at or close to ends of an upper part of the hoisting device, the load take-up means comprise take-up elements arranged at or close to corners of a lower part of the hoisting device, and the controllable pivoting means comprise at least one pivot bearing arranged between the suspending means and the take-up elements.

3. Hoisting device according to claim 1 or 2, wherein the suspending means are incorporated in an upper hoisting frame and the load take-up means are incorporated in a lower hoisting frame which is mounted pivotally on the upper hoisting frame via the at least one pivot bearing.

4. Hoisting device according to claim 3, wherein the controllable pivoting means comprise a mounting member for the upper hoisting frame which is arranged on an upper side of the lower hoisting frame and is bearing-mounted pivotally in the lower hoisting frame, as well as an actuator arranged between the lower hoisting frame and the mounting member.

5. Hoisting device according to claim 1 or 2, wherein the suspending means comprise cable sheaves around which the hoisting cables are trained, and wherein the load take-up means are incorporated in a hoisting frame which is suspended pivotally from the cable sheaves via the at least one pivot bearing.

6. Hoisting device according to claim 5, wherein the controllable pivoting means comprise a bearing member for the cable sheaves which is arranged on an upper side of the hoisting frame and is bearing-mounted pivotally in the hoisting frame, as well as an actuator arranged between the hoisting frame and the bearing member.

7. Hoisting device according to claim 4 or 6, wherein the controllable pivoting means comprise a control connected to the actuator.

8. Hoisting device according to claim 7, wherein the controllable pivoting means comprise a position sensor connected to the control.

9. Hoisting device according to claim 7 or 8, wherein the control is configured to control the actuator initially in a first direction and, after a turning point has been reached, to control the actuator in a second direction opposite thereto.

10. Hoisting device according to claim 9, wherein the turning point is determined by a duration set by the control or a movement performed by the actuator.

11. Hoisting device according to claim 9 or 10, wherein the turning point is determined by a detection by the position sensor.

12. Hoisting device according to claim 3 or 4, wherein the upper hoisting frame comprises a headblock and the lower hoisting frame comprises a spreader.

13. Hoisting device according to any one of the foregoing claims, wherein the suspending means comprise cable sheaves around which the hoisting cables are trained, and wherein the load take-up means comprise twistlocks.

14. Hoisting device according to claim 13, wherein the suspending means comprise a plurality of pairs of cable sheaves and wherein the controllable pivoting means are configured to displace one of the cable sheaves of each pair relative to the other cable sheave.

15. Hoisting device according to claim 13 when dependent on claim 4 or 6, wherein the mounting member is situated substantially in a plane determined by one of the cable sheaves.

16. Method for setting down at a desired position a hoisting device suspended from hoisting cables or a load taken up thereby, comprising the steps of:- paying out the hoisting cables until the hoisting device or the load is situated in the vicinity of the desired position,- detecting a deviation between the position of the hoisting device or the load after paying out of the hoisting cables and the desired position,- performing a correction in order to reduce or eliminate the deviation, and - paying out the hoisting cables further until the hoisting device or the load is situated at the desired position,wherein the correction is performed by making the hoisting device and the load optionally taken up thereby pivot relative to the hoisting cables about a horizontal longitudinal axis of the hoisting device which extends substantially through a centre of gravity of the hoisting device and the load optionally taken up thereby, such that an underside of the hoisting device or the load taken up thereby is displaced substantially horizontally.

17. Method according to claim 16, wherein the correction is performed by making two parts of the hoisting device pivot relative to each other.

18. Method according to claim 17, wherein the one of the pivoting parts comprises an upper hoisting frame which is suspended from the hoisting cables, and the other pivoting part comprises a lower hoisting frame which is mounted on the upper hoisting frame and takes up the load.

19. Method according to claim 17 or 18, wherein the correction is performed by operating an actuator which is connected to the two pivoting parts.

20. Method according to claim 16, wherein the hoisting cables are trained round pairs of cable sheaves on the hoisting device, and the correction is performed by displacing one of the cable sheaves of each pair relative to the other cable sheave.

21. Method according to any one of the claims 16-20, wherein the correction is performed by a control connected to the hoisting device or incorporated therein.

22. Method according to any one of the claims 16-21, wherein the deviation is detected by a position sensor connected to the hoisting device or incorporated therein.

23. Method according to any one of the claims 16-22, wherein the correction is performed for a determined amount of time or over a determined distance.

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