Method for lifting a slender object and lifting yoke

Abstract

A method of lifting a slender object (2) from the ground using a lifting yoke (1) connected to a lifting means, wherein a beam-shaped support frame (10) of the lifting yoke extends in the longitudinal direction (20) of the object, and slings (6) provided at the ends of the support frame lift the object. The object is lifted in the slings by the following steps: holding a first outer end (6-1) of the sling with a first holding means provided at the end of the support frame and allowing the first outer end to hang down from the first holding means to a position near the object; paying out a lead line from the end using a lead line winch, supplying the lead line under the object, and connecting the lead line to a second outer end (6-2) of the sling hanging from the first holding means; retrieving the lead line so that the sling is brought under the object and to the relevant end; and connecting the second outer end of the sling to a second holding means provided at the end, thereby forming one of the slings for the object.

Description

Technical Field

[0001] The present invention relates to a method for lifting a slender object from the ground using a lifting yoke coupled to a lifting device, wherein a support frame of the lifting yoke extends in the longitudinal direction of the object, and wherein slings provided at the ends of the support frame lift the object. The present invention also relates to a lifting yoke applied to the method, a lifting crane provided with the lifting yoke, and a ship provided with the lifting crane. Background Art

[0002] The present invention will be illustrated with reference to the placement of (components of) an offshore wind turbine. However, this reference does not imply that the present invention is limited thereto, and the method and the corresponding lifting yoke can equally well be applied to lifting and placing any other structure. Thus, the present invention can be applied, for example, to the lifting of components of other offshore infrastructure such as breakwaters, radars, and other towers, and can also be applied to the lifting of components for onshore applications.

[0003] When placing a component of a wind turbine, such as a foundation pile, on an underwater bottom, the foundation pile is lifted from a ship using a lifting crane. For the purpose of lifting such a foundation pile, a lifting tool such as a sling or a lifting yoke is attached to the foundation pile. For the purpose of lifting, such a lifting yoke is connected to the load hook of the lifting crane. Then, the foundation pile lifted in this way can be brought to a vertical position and lowered onto or into the underwater bottom using a tipping tool or other tools, after which the foundation pile is disconnected from the lifting crane.

[0004] According to the prior art, the slender object to be lifted is manually connected to the lifting yoke. Thus, the object is largely manually arranged in the sling. However, the slender object to be lifted, such as the above-mentioned foundation pile, is becoming heavier and larger, and thus, it is no longer safe to perform the above operations substantially manually. In addition, the swinging of the lifting tool caused by the action of waves and wind will cause the deck personnel to be in a more unsafe state and may also cause damage to the object.

[0005] Therefore, it is necessary to support a sling hoist, an auxiliary crane, a forklift, or a similar auxiliary device so that a lifting tool such as a lifting yoke can be managed in order to be able to arrange the object therein. The available space on the working deck of a ship being installed is often already occupied by the objects to be transported, so it is difficult to apply these auxiliary devices. Summary of the Invention

[0006] Therefore, an object of the present invention is to provide a method for lifting a slender object from the ground using a lifting yoke coupled to a lifting means, wherein at least some of the above-mentioned disadvantages and risks are avoided.

[0007] To this end, the present invention provides a method for lifting an elongate object from the ground using a lifting yoke coupled to a lifting means, wherein a support frame of the lifting yoke extends in the longitudinal direction of the object, and wherein slings provided at the ends of the support frame lift the object. The method is characterized in that the object is lifted in the slings by the following steps:

[0008] a) Holding a first outer end of the sling with a first holding means provided at an end of the support frame and allowing the first outer end of the sling to hang down from the first holding means to a position near the object;

[0009] b) Paying out a lead line from an end using a lead line winch, supplying the lead line under the object, and coupling the lead line to a second outer end of the sling hanging from the first holding means;

[0010] c) Retrieving the lead line so that the sling is brought under the object and to the relevant end;

[0011] d) Coupling the second outer end of the sling to a second holding means provided at the end, thereby forming one of the slings for the object.

[0012] The method of the present invention in principle requires less human input, at least at the location of the work platform where there may be a risk of accidental movement. Therefore, the method is inherently safe and can be applied in adverse weather conditions. As a result, less time is wasted waiting for acceptable weather conditions.

[0013] The support beams of the support frame may be elongate, for example, in the form of a beam. The support frame may also be in the form of a cylinder.

[0014] An embodiment of the device according to the present invention is characterized in that steps a) to d) are carried out at both ends of the support frame. Particularly effective is an embodiment in which steps a) to d) are carried out simultaneously at both ends of the support frame.

[0015] Another embodiment includes a method in which an auxiliary cable is paid out from an end using an auxiliary cable winch, and before step a), the auxiliary cable is coupled to a second outer end of the sling hanging from the first holding means, step a) is carried out, and the auxiliary cable is decoupled from the second outer end before step b).

[0016] Yet another embodiment relates to a method in which, in step a), the sling descends on one side of the object, and in step b), the lead line descends on the other side of the object.

[0017] Another embodiment includes a method in which, in step b), the lead line is supplied under the object by coupling the lead line to an outer end of a connection line provided under the object.

[0018] In yet another embodiment, the method has the following feature: The other outer end of the connecting line is coupled to the second outer end of a sling that is suspended from the first holding means.

[0019] The method can in principle be applied to lifting a slender object from any ground suitable for a slender object. The embodiment in which the advantages of the method become particularly evident is characterized in that the ground comprises the working deck of a ship that is optionally floating. The method of the present invention is also advantageously applied to the following embodiments of the method: The slender object comprises a wind turbine or a component thereof, or a foundation pile for a wind turbine. In addition, the method is also applicable to other applications, such as in the case of installing an oil and gas platform or in the case of demolishing such a platform.

[0020] Another aspect of the present invention relates to a lifting yoke for a slender object, which is adapted to be applied to the method of the present invention. The lifting yoke comprises a support frame configured to extend in the longitudinal direction of the object and be coupled to a lifting means, and at the ends is provided with slings for lifting the object, wherein each end of the support frame comprises a first holding means for the first outer end of the sling and a second holding means for the second outer end of the sling, and each end of the support frame further comprises a messenger winch configured to pay out a messenger cable and couple it to the second outer end of the sling that is suspended from the first holding means, such that when the messenger cable is retracted, the sling is brought under the object and to the relevant end until the second outer end is in a position where it can be coupled to the second holding means, thereby forming one of the slings for the object upon coupling.

[0021] A further improved lifting yoke according to an embodiment of the present invention is characterized in that each end of the support frame further comprises an auxiliary cable winch configured to pay out an auxiliary cable from the end.

[0022] The messenger winch and / or the optional auxiliary cable winch can in principle be configured and driven in any manner known to a person skilled in the art. In a practical embodiment of the present invention, the lifting yoke comprises at least one drive device, in particular an electric drive device and / or a hydraulic drive device, for driving the messenger winch and / or the optional auxiliary cable winch.

[0023] In an embodiment in which the lifting yoke is provided with a drive device that can be remotely controlled, the convenience of operation is further improved.

[0024] An embodiment in which the messenger winch and / or the optional auxiliary cable winch of the lifting yoke are releasably connected to the lifting yoke provides a versatile solution.

[0025] The lifting yoke according to the invention can advantageously be connected to the lifting cable of a lifting crane in a known manner. Using a lifting crane provided with the lifting yoke according to the invention, it is in principle possible to safely lift any elongated object, wherein at least some of the above advantages of attaching the object to the lifting yoke can be achieved.

[0026] Any type of lifting crane can in principle be provided with a lifting yoke according to the invention. However, the advantages of the lifting yoke become particularly evident when it is connected to the lifting cable of a lattice boom crane. Such a lifting crane uses a boom that is rotatable about a horizontal axis of rotation, wherein the lifting crane itself can usually also rotate about a vertical axis of rotation provided by the crane base.

[0027] The method and the lifting yoke have additional advantages when used on a ship, for which purpose the ship is provided with the above-mentioned lifting crane. An additional advantage of the invention is that no or only relatively light guide cables and auxiliary cables need to be handled. This advantage is becoming increasingly important because elongated objects are becoming heavier, with the result that the lifting material also has to take increasingly heavy forms and can no longer be manually manipulated. According to the invention, it is only necessary to manipulate relatively light guide cables and auxiliary cables.

[0028] The embodiments of the invention described in this patent application can be combined in any possible combination of these embodiments, and each embodiment can alone form the subject matter of a divisional patent application. Description of the Drawings

[0029] The invention will now be further elucidated with reference to the following drawings, but the invention is not limited thereto. In the drawings:

[0030] Figure 1 is a schematic perspective view of a lifting yoke suspended on a lifting crane according to an embodiment of the invention;

[0031] Figures 2-1 to 2-10 is a schematic perspective view of different steps of an embodiment of the method of applying the lifting yoke according to the invention;

[0032] Figure 3-1 is a schematic perspective sectional view of the end of the lifting yoke in a first case according to an embodiment of the invention;

[0033] Figure 3-2 is a schematic perspective sectional view of the end of the lifting yoke in a second case according to an embodiment of the invention; Figures 4-1 to 4-3 is a schematic side view of a holding means according to an embodiment of the invention; and, finally

[0034] Figures 5-1 to 5-3 is according to an embodiment of the invention in Figures 4-1 to 4-3Schematic front view of the retaining means as shown. Detailed implementation

[0035] Reference Figure 1 , shows a lifting yoke 1 according to an embodiment of the present invention. The lifting yoke 1 is configured to lift an elongated object, such as the shown foundation pile 2. The foundation pile 2 to be lifted is located on the working deck 3 of a ship (not further shown) together with other foundation piles 2. For example, the foundation pile 2 can be located in a rack suitable for this purpose, and the rack includes a prefabricated support 4 (for example, as Figure 2-10 shown).

[0036] The lifting yoke 1 includes a beam-shaped support frame 10, which is implemented as a lattice structure in the shown embodiment. When lifting the foundation pile 2, the support frame 10 is configured to extend in the longitudinal direction 20 of the foundation pile 2. The lifting yoke includes two box-shaped ends 11, which are structurally connected to the support frame 10, and both are provided with pivotable connectors 12 on the upper side. For the purpose of connecting to a lifting crane (not further shown), each connector 12 is suspended on a lifting hook 5 by a cable 51, as shown in Figure 2. The lifting yoke 5 is suspended on the boom of the lifting crane by a lifting cable 50.

[0037] As Figure 2-9 and Figure 2-10 shown, the ends 11 are respectively provided with slings 6 for lifting the foundation pile 2. According to the shown embodiment, the present invention relates to the way the foundation pile 2 is suspended in the sling 6. This requires less manual manipulation of components by personnel on the working deck 3. Therefore, it is sufficient to manually manipulate the less heavy towing cable and lifting cable.

[0038] Reference Figure 3-1 and Figure 3-2 , shows a lifting yoke 1 according to an embodiment of the present invention, particularly the interior of the box-shaped end 11 of the lifting yoke 1. The end 11 of the support frame 10 includes a first retaining means 13-1 for the first outer end 6-1 of the sling 6. The first retaining means 13-1 is structurally connected to the side wall 11-1 of the box-shaped end 11 and includes a cylindrical pin that extends from the side wall 11-1 towards the interior of the end 11, around which the first outer end 6-1 of the sling 6 can be trimmed. The outer end 6-1 can form a loop of the double-strand sling 6, but can also take the form of an eye. Structurally connected is to be understood to mean that the connection can transfer load, in this case, from the first retaining means 13-1 to the end 11 (its wall) to transfer load.

[0039] The end portion 11 further includes a second retaining means 13-2 for the second outer end 6-2 of the sling 6. The second retaining means 13-2 is also structurally connected to a part of the box-shaped end portion 11 and includes a cylindrical pin 131 that extends towards the interior of the end portion 11 and is movable together with the hydraulic cylinder 130 between an open position and a closed position towards the side wall 11-2 opposite to the side wall 11-1. In the open position, the pin 131 is moved away from the side wall 11-2, and in the closed position, the pin 131 extends into an opening 11-3 arranged in the side wall 11-2 (see Figure 4-1 ).

[0040] The end portion 11 further includes two cable winches (14-1, 14-2) configured to pay out two cables (15-1, 15-2). The cables (15-1, 15-2) are coupled to the second outer end 6-2 of the sling 6 that hangs from the first retaining means 13-1. As will be further explained below, this allows the sling 6 to be brought under the foundation pile 2 and to the relevant end portion 11 when the cables (15-1, 15-2) are retracted, until the second outer end 6-2 of the sling 6 is in a position where it can be coupled to the second retaining means 13-2, thus forming one of the slings 6 for the foundation pile 2. The cable winches (14-1, 14-2) are also structurally connected to the box-shaped end portion 11 (its side wall 11-1). In the illustrated embodiment, the cables (15-1, 15-2) further extend over disks (16-1, 16-2) arranged against the side wall 11-2 so as to be able to bring the cables (15-1, 15-2) and the second outer end 6-1 of the sling 6 coupled thereto near the second retaining means 13-2.

[0041] The end portion 11 is also provided with an auxiliary cable winch 17 configured to pay out an auxiliary cable 18 from the end portion 11. In the steps of the method, the auxiliary cable 18 is also coupled to the second outer end 6-2 of the sling 6 that hangs from the first retaining means 13-1, as will be further explained below. The auxiliary cable winch 17 is further structurally connected to the box-shaped end portion 11 (its side wall 11-2). In the illustrated embodiment, the auxiliary cable 18 extends over a disk 19 (which is structurally connected to the box-shaped end portion 11) so as to be able to bring the auxiliary cable 18 near the second outer end 6-2 of the sling 6 for coupling thereto.

[0042] The cable winches (14-1, 14-2) and the auxiliary cable winch 17 are optionally (structurally) connected to a part of the end portion 11 of the lifting yoke 1 in a releasable manner.

[0043] The lifting yoke 1 is further provided with at least one drive device (in particular a hydraulic drive device and / or an electric drive device) for driving the lead cable winches (14-1, 14-2) and the auxiliary cable winch 17, and also for driving the hydraulic cylinder 130 of the second holding means 13-2. This drive device is preferably remotely controllable, for example by the operator of the lifting crane or other personnel.

[0044] In Figures 4-1 to 4-3 and from Figures 5-1 to 5-3 the front view shows the manner in which the second outer end 6-2 of the sling 6 is connected to the second holding means 13-2. In the open position (see Figure 4-1 and 5-1 ), by pulling back the lead cables (15-1, 15-2), the second outer end 6-2 of the sling 6 can be moved past the pin 131 of the second holding means 13-2. Then the pin 131 slides towards the side wall 11-2 under the action of the hydraulic cylinder 130 and enters the closed position, as shown in Figure 4-2 , 4-3 , 5-2 and 5-3. In this closed position, the annular second outer end 6-2 is in its position above the pin 131. Then, by paying out the lead cables (15-1, 15-2), the annular second outer end 6-2 moves towards the pin 131 until the outer end 6-2 pulls itself around the pin 131. In this way, the second outer end 6-2 is coupled to the second holding means 13-2, so that the sling 6 coupled to the lifting yoke 1 can carry a load, such as the foundation pile 2.

[0045] Reference Figures 2-1 to 2-10 shows the different steps of the method according to an embodiment of the present invention, in which the above-mentioned lifting yoke 1 is applied.

[0046] Figure 2-1 shows the first step of the method of lifting the slender foundation pile 2 from the working deck 3 of the ship. For this purpose, the above-described embodiment of the lifting yoke 1 is coupled to a lifting crane (not shown) located on the working deck 3. As described above with reference to Figure 3-1 and 3-2 , the foundation pile 2 located on the working deck 3 is lifted in the sling 6 by holding the first outer end 6-1 of the sling 6 with the first holding means 13-1 provided at the end 11 of the support frame 10 of the lifting yoke 1. The sling 6 hangs from the first holding means 13-1 such that the sling 6 hangs freely downwards from the holding means 13-1 to a position near the foundation pile 2 or the working deck 3 ( Figure 1 and 2-1 ). In order to prevent the sling 6 with one end hanging freely from swinging, in one embodiment, the auxiliary cable winch 17 can be used to pay out the auxiliary cable 18 from the end 11, and the auxiliary cable 18 can be coupled to the second outer end 6-2 of the sling 6 hanging from the first holding means 13-1 ( Figure 2-1)。Then, by using the auxiliary cable winch 17 to pull back the auxiliary cable 18, the second outer end 6-2 is pulled up against the lifting yoke 1, as seen in Figure 2-2 . This shortens the length of the sling 6 so that it can be more easily displaced relative to the working deck 3 by the lifting crane to the position above the pile 2 to be lifted, as shown in Figure 2-2 .

[0047] In a subsequent step ( Figure 2-3 ), the auxiliary cable 18 is paid out again, and the second outer end 6-2 of the sling 6 is brought near the pile 2 to be lifted by its own weight, and if necessary, onto the working deck 3. The sling 6 and the connected auxiliary cable 18 are located on one side of the pile 2 to be lifted here. In a subsequent step ( Figure 2-4 ), one or more guide cables 15 (15-1, 15-2) are paid out at each outer end 11 by using the guide cable winches 14 (14-1, 14-2), where the free outer ends of the guide cables 15 (15-1, 15-2) are located near the pile 2. The guide cables 15 (15-1, 15-2) are suspended on different sides of the pile 2 here together with the connected sling 6 and auxiliary cable 18. Then the second outer end 6-2 of the sling is disconnected from the auxiliary cable 18, and the auxiliary cable is pulled back by using the auxiliary cable winch 17 ( Figure 2-5 ).

[0048] In a subsequent step, the guide cables 15 (15-1, 15-2) are fed under the pile 2 to be lifted. For example, this can be done by connecting the free outer ends of the guide cables 15 (15-1, 15-2) to the outer ends 19-1 of the connecting line 19 provided under the pile 2 to be lifted. As shown in Figure 2-5 , the connecting line 19 can be arranged, for example, above another pile 2a located under the pile 2 to be lifted.

[0049] In a subsequent step, as shown in Figure 2-6 , the connecting line 19 extends above the pile 2a and under the pile 2 to be lifted. The connecting line 19 thereby moves the free outer ends of the guide cables 15 (15-1, 15-2) under the pile 2 and to the side where the second outer end 6-2 of the sling 6 of the pile 2 is located.

[0050] Then, the guide cables 15 (15-1, 15-2) are connected to the second outer end 6-2 of the sling 6 that still hangs from the first holding means 13-1 ( Figure 2-7 ).

[0051] Now, by using the guide cable winches 14 (14-1, 14-2) to retract the guide cables 15 (15-1, 15-2), the sling 6 is brought under the pile 2 and to the relevant end 11, as shown in Figure 2-8As shown until the second outer end 6-2 of the sling 6 can be coupled to the second retaining means 13-2.

[0052] Obviously, the above method steps are preferably carried out at the two ends 11 of the support frame 10 of the lifting yoke 1, and preferably carried out simultaneously at the two ends 11.

[0053] The sling 6 thus formed can now lift the pile 2 together with the two ends 11 of the lifting yoke 1 and displace them, as Figure 2-9 and Figure 2-10 shown.

[0054] Obviously, the above-described embodiment of the lifting yoke must be provided with peripheral equipment, such as hydraulic power sources and electric power sources, supply pipes therefor, etc. Such peripheral equipment will not be described in further detail.

Claims

1. A method for lifting a slender object from the ground using a lifting yoke coupled to a lifting means, wherein a beam-like support frame of the lifting yoke extends in the longitudinal direction of the object, and wherein slings provided at the ends of the support frame lift the object, and wherein the object is lifted in the slings by the following steps: a) Holding a first outer end of the sling with a first holding means provided at an end of the support frame and allowing the first outer end of the sling to hang down from the first holding means to a position near the object; b) Paying out a lead line from the end using a lead line winch, supplying the lead line under the object, and coupling the lead line to a second outer end of the sling hanging from the first holding means; c) Retrieving the lead line such that the sling is brought under the object and to the relevant end; d) Coupling the second outer end of the sling to a second holding means provided at the end, thereby forming one of the slings for the object.

2. The method according to claim 1, wherein, steps a) to d) are carried out at both ends of the support frame.

3. The method according to claim 2, wherein, steps a) to d) are carried out simultaneously at both ends of the support frame.

4. The method according to any one of the preceding claims, wherein, an auxiliary cable is paid out from the end using an auxiliary cable winch, and before step a), the auxiliary cable is coupled to the second outer end of the sling hanging from the first holding means, step a) is carried out, and before step b), the auxiliary cable is decoupled from the second outer end.

5. The method according to any one of claims 1 - 3, wherein, in step a), the sling descends on one side of the object, and in step b), the lead line descends on the other side of the object.

6. The method according to any one of claims 1 - 3, wherein, in step b), the lead line is supplied under the object by coupling the lead line to an outer end of a connection line provided under the object.

7. The method according to claim 6, wherein, the other outer end of the connection line is coupled to the second outer end of the sling hanging from the first holding means.

8. The method according to any one of claims 1 - 3, wherein, the ground includes a working deck of a ship.

9. The method according to any one of claims 1 - 3, wherein, the slender object includes a wind turbine or a component thereof, or a foundation pile for a wind turbine.

10. Lifting yoke for an elongate object, comprising a beam-shaped support frame configured to extend in the longitudinal direction of the object and to be coupled to lifting means, and the support frame being provided at its ends with slings for lifting the object, wherein each end of the support frame comprises first retaining means for a first outer end of the sling and second retaining means for a second outer end of the sling, and each end of the support frame further comprises a lead line winch configured to pay out a lead line and to couple the lead line to the second outer end of the sling hanging from the first retaining means, such that when the lead line is retracted, the sling is brought under the object and to the relevant end until the second outer end is in a position where the second outer end can be coupled to the second retaining means, thereby forming one of the slings for the object upon coupling.

11. The lifting yoke according to claim 10, wherein, each end of the support frame further comprises an auxiliary line winch configured to pay out an auxiliary line from the end.

12. The lifting yoke according to claim 10 or 11, wherein, the lifting yoke comprises at least one drive device for driving the lead line winch and / or the auxiliary line winch.

13. The lifting yoke according to claim 12, wherein, the drive device can be remotely controlled.

14. The lifting yoke according to claim 10 or 11, wherein, the lead line winch and / or the auxiliary line winch are releasably connected to the lifting yoke.

15. A lifting crane provided with the lifting yoke according to claim 10 or 11.

16. A ship provided with the lifting crane according to claim 15.

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