Wire back tension device

Abstract

A device for tensioning an elongated hoisting member, comprises: a first friction-generating member rotatably supported around a first support member; a second friction-generating member rotatably supported around a second support member, the first and second friction-generating members being adapted to provide friction to the elongated hoisting member when the friction-generating members are pressed against each other with a portion of the elongated hoisting member therebetween. A brake is provided for braking the rotation of the friction-generating members around the support members. There is also described a system that includes such a device, as well as a method for operating such a system.

Claims

1. Device for tensioning an elongated hoisting member, comprising: a first friction-generating member rotatably supported around a first support member; a second friction-generating member rotatably supported around a second support member, said first and second friction-generating members being adapted to provide friction to the elongated hoisting member when said first and second friction-generating members are pressed against each other with a portion of the elongated hoisting member there-between, and wherein said first and second friction-generating members are passively, rotatably supported around said first and second support members respectively; a motorless shaft assembly comprising a shaft coupled to the first friction-generating member and a brake coupled to the shaft, wherein the brake is configured to stop the rotation of said first friction-generating member around said first support member.

2. Device according to claim 1, wherein said first and second friction-generating members comprise a plurality contact pads being included in a first and a second friction belt, respectively.

3. Device according to claim 1, wherein said brake is a disc brake.

4. Device according to claim 3, wherein the brake is configured such that the braking force may be hydraulically or pneumatically adjusted.

5. Device according to claim 1, wherein the brake is configured such that the braking force exerted by said brake on said first and second friction-generating members may be manually adjusted.

6. Device according to claim 1, wherein said first and second friction-generating members are configured such that they may be pressed against each other by means of a plurality of hydraulic cylinders, each with a head part connected to one of said first support and second support member and a base part connected to the other of said first and second support members.

7. Device according to claim 1, wherein the device further comprises a load distribution member configured to provide a uniform load distribution to a portion of said elongated hoisting member located between said first and second friction-generating members.

8. Device according to claim 7, wherein said load distribution member includes a plurality of rollers being provided under at least a portion of said first and second friction-generating members.

9. Device according to claim 1, further comprising a connection for water supply for cooling of said brake.

10. Device according to claim 1, wherein a first end of the motorless shaft assembly comprises the brake and a second end of the motorless shaft assembly, opposite the first end, comprises a gear wheel coupled to the shaft.

11. A crane for lifting a load using an elongated hoisting member, comprising: a pedestal; a winch drum configured to store the elongated hoisting member; a drive configured to spool to the elongated hoisting member onto the winch drum; and a tensioning device coupled to the pedestal and comprising: a first friction-generating member rotatably supported around a first support member a second friction-generating member rotatably supported around a second support member, said first and second friction-generating members being adapted to provide friction to the elongated hoisting member when said first and second friction-generating members are pressed against each other with a portion of the elongated hoisting member there-between, and wherein said first and second friction-generating members are passively, rotatably supported around said first and second support members respectively; and a brake configured to stop the rotation of said first friction-generating member around said first support member.

12. The crane of claim 11, wherein the tensioning device is positioned inside the pedestal.

13. The crane of claim 11, wherein the tensioning device comprises a motorless shaft assembly comprising a shaft coupled to the first friction-generating member and to the brake.

14. The crane of claim 11, wherein the first and second friction-generating members of the tensioning device comprise a plurality contact pads being included in a first and a second friction belt, respectively.

15. The crane of claim 11, wherein the brake of the tensioning device is configured such that the braking force may be hydraulically or pneumatically adjusted.

16. The crane of claim 11, wherein the tensioning device further comprises a load distribution member configured to provide a uniform load distribution to a portion of said elongated hoisting member located between said first and second friction-generating members.

17. A method for lifting a load with an elongated hoisting member, comprising: (a) activating a winch drum of a crane to spool the elongated hoisting member onto the winch drum; (b) pressing a first friction-generating member of a tensioning device of the crane against a second friction-generating member of the tensioning device with a portion of the elongated hoisting member there-between, wherein said first and second friction-generating members are passively, rotatably supported around a first support member and a second support member respectively, of the tensioning device; and (c) applying a braking force to the elongated hoisting member from the tensioning device as the elongated hoisting member is spooled onto the winch drum, whereby the tensioning device tensions the elongated hoisting member as the hoisting member is spooled onto the winch drum.

18. The method of claim 17, wherein (c) comprises increasing the braking force applied to the elongated hoisting member from the tension device to maintain a substantially constant tension in the elongated hoisting device as the elongated hoisting device is spooled onto the winch drum.

19. The method of claim 17, wherein (c) comprises: (c1) frictionally engaging the elongated hoisting member with a plurality of contact pads of the tensioning device; and (c2) applying a braking force to a shaft of a motorless shaft assembly of the tensioning device from a brake of the motorless shaft assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following is described an example of an exemplary embodiment illustrated in the accompanying drawings, wherein:

(2) FIG. 1 shows, in a side view, a tensioning device according to the present disclosure;

(3) FIG. 2 shows, in a side view, a part of the tensioning device from FIG. 1;

(4) FIG. 3A-B shows, in an end view and in a top view, the part of the tensioning device of FIG. 2; and

(5) FIG. 4 shows, in a side view and in reduced scale, a tensioning according to the present disclosure as integrated into a lifting crane.

DETAILED DESCRIPTION OF THE DISCLOSED EXEMPLARY EMBODIMENTS

(6) In the following, the reference numeral 1 will indicate a tensioning device according to the present disclosure. Identical reference numerals indicate identical or similar features in the drawings. It should also be noted that the drawings are shown schematically and simplified and that the various features in the drawings are not necessarily drawn to scale.

(7) Attention is first drawn to FIGS. 1, 2 and 3A-B showing a tensioning device 1 according to the first aspect of the present disclosure in different views. The tensioning device 1 comprises a first tension-generating member 2, in the form of a first belt, rotatably supported around a first support member 6, and a second tension-generating member 4, in the form of a second belt, rotatably supported around a second support member 8. The first and second support members 6, 8 with respective belts 2, 4 give the tensioning 1 device the look of two caterpillar tracks facing each other with an elongated hoisting member 10, here shown as only a short part of a wire rope, therebetween. Each of the belts 2, 4 comprise a plurality of contact pads 12 constituting outer, friction-creating parts of each belt 2, 4. In use, some of the contacts pads 12 will be in contact with the wire rope 10 and create friction sufficient for the wire rope to rotate the belts 2, 4 around their respective support members 6, 8. An inner portion of each of the belts 2, 4 comprises a chain 14 to which the contacts pads 12 are connected. The chain 14 engages a gear wheel 16, only indicated by its position in FIGS. 3A-B, that rotates a not shown shaft connected to a brake 18 via a gear box 20 as best seen in FIGS. 3A-B. The friction between the belts 2, 4 and the wire rope 10 is ensured by a plurality of hydraulic cylinders 22 with a head part 24 connected to the first support member 6 and a base part 26 connected to the second support member 8, the hydraulic cylinders 22 pressing the two support members 6, 8 against each other. The cylinders 22 may thereby be used to adjust the pressure between the two belts 2, 4 and thus also the friction between the belts 2, 4 and the wire rope 10. In the shown embodiment, the cylinders 22 are manually adjustable and do not require connection to any external hydraulic supply and power unit. Further, in the shown embodiment the brake 18 comprises a disc brake with a braking force controllable by means of not shown hydraulically actuated callipers. The braking energy primarily ends up as heat which is cooled away by means of a not shown water supply.

(8) Further, in the shown embodiment the belts 2, 4 are passively, rotatably supported around their respective support members 6, 8, implying that there is no active drive on the brake 18. The wire rope 10 is spooled in by means a not shown winch that is located downstream of the tensioning device 1, the tensioning device 1 being adapted to create the desired tension in the wire rope 10 as it is being spooled onto the winch drum. In order to ensure a uniform load distribution, the tensioning device 1 is provided with load distribution members, here in the form of pressure rollers not shown in detail, between the each of the support members 6, 8 and their respective belts 2, 4 in a portion of the support members 6, 8 facing each other. The pressure rollers are provided in cartridges 27, where the chain part 14 of the belts 2, 4 glide over the pressing rollers in use. The tensioning device 1 is also shown provided with tie bars 28 for the integration of the tensioning device 1 into a crane 30, as shown in FIG. 4, or for the connection inside a shipping container as described above. Each support member 6, 8 is provided with a spanning member 29 abutting the chain 14 in use, and adjustable to regulate the tension/span in the belts 2, 4 themselves. In an alternative, not shown, embodiment the span in the belts 2, 4 could adjustable by supporting said gear wheels 16 on eccentric shafts, so as to adjust the span/tension in each of the belts 2, 4 by simply turning the respective eccentric shafts.

(9) In FIG. 4 a tensioning device according to the present disclosure is shown integrated into a pedestal 30 of a crane not shown in detail. The tie bars 28 of the tensioning device 1, which are not visible in the figure, are clamped to cross-bars 32 inside the crane pedestal 30. In the shown embodiment, the tensioning device 1 is fixedly, non-rotatably supported inside the pedestal 30. A not shown winch is provided under deck, i.e. downstream of the tensioning device 1, of a not shown vessel on which the crane pedestal 30 is placed. In alternative embodiment, a tensioning device 1 according to the present disclosure may be connected inside the pedestal 28 by bolting and/or welding or by a variety of different ways as will be understandable to a person skilled in the art. In the shown embodiment, the brake 18 are provided at an upper portion of the tensioning device 1, i.e. opposite of what was shown in FIG. 1.

(10) The tensioning device 1 according to the present disclosure will typically not be in use when paying out wire rope 10. Neither will the tensioning device 1 be in use during heave compensation. When spooling in a wire rope 10 after a load has been placed on a seabed, the tensioning device 1 may be activated during the spooling of the last few hundred meters or more, e.g. during the last 500 meters or so. In the shown embodiment, the braking force of the brake 18 is step-less adjustable, and preferably the braking force is increased as the wire rope 10 is being spooled in, in order to keep a substantially constant tension in the wire rope 10 stored on the not shown winch drum.

(11) It should be noted that the above-mentioned embodiments illustrate rather than limit the present disclosure, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb comprise and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article a or an preceding an element does not exclude the presence of a plurality of such elements.

(12) The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.