Load guiding arrangement

Abstract

A load guiding arrangement realized for mounting to a crane, which load guiding arrangement comprises a number of load guides, wherein a load guide comprises a guide wire extending from a lower level of the crane to an upper level of the crane; a bridging connector realized to bridge a gap between the guide wire and a control wire, which bridging connector is free to travel along the guide wire and the control wire according to a vertical displacement of a load; and a control wire extending from a lower level of the crane, through the bridging connector to a lifting connector for connecting to the load (4), and through the bridging connector again to an upper level of the crane is provided.

Claims

1. A load guiding arrangement configured to mount to a crane, the load guiding arrangement including a plurality of load guides, wherein a load guide of the plurality of load guides comprises: a guide wire extending from a lower level of the crane to an upper level of the crane; a bridging connector configured to bridge a gap between the guide wire and a control wire, the bridging connector being free to travel along the guide wire and the control wire according to a vertical displacement of a load; and the control wire extending from the upper level of the crane, through the bridging connector to a lifting connector for connecting to the load, and through the bridging connector again to the lower level of the crane; wherein the bridging connector includes a plurality of pulley wheels, a pulley wheel of the plurality of pulley wheels being arranged to travel along the guide wire; wherein the bridging connector includes a housing with two housing plates in an open casing construction, and wherein the housing plates are arranged parallel to each other, and are connected by a number of axles about which the pulley wheels are free to rotate whereby the load can be steadily lifted without any significant lateral displacement, even in strong wind conditions.

2. The load guiding arrangement according to claim 1, comprising a winch arrangement for controlling tension in the guide wire.

3. The load guiding arrangement according to claim 2, comprising a remote control means for remote control of the winch arrangement.

4. The load guiding arrangement according to claim 1, wherein the control wire is realized for mounting to the lifting connector of a component lifting frame.

5. The load guiding arrangement according to claim 1, comprising a lower traverse for mounting to the crane in a lower region and an upper traverse for mounting to the crane in an upper region and wherein the guide wire is connected between the lower traverse and the upper traverse.

6. The load guiding arrangement according to claim 1, wherein the plurality of load guides are a pair of load guides.

7. The load guiding arrangement according to claim 6, wherein the pair of load guides are arranged on opposite vertical sides of the crane.

8. The load guiding arrangement according to claim 1, comprising a fold-in arrangement for retracting an upper traverse.

9. The load guiding arrangement according to claim 8, wherein the fold-in arrangement comprises a fold-in wire connected to a hinged upper crane traverse and a fold-in winch for adjusting the tension of the fold-in wire.

10. A crane configured for lifting a load, the crane comprising: a lifting wire for connecting to the load to be lifted; a lifting wire winch for controlling tension in the lifting wire; the load guiding arrangement according to claim 1; and the lifting connector for connecting the control wire of the load guide to the load.

11. A method of operating the crane according to claim 10, comprising: bringing the crane into an upright position; arranging a control wire of a load guide over a lifting connector of a load; increasing tension in a guide wire; increasing tension in the control wire; and actuating a lifting wire winch to lift the load, so that a bridging connector of the load guide travels along the guide wire and the control wire according to a vertical displacement of the load.

12. The method according to claim 11, wherein the crane is operated to lift a wind turbine component at a wind turbine installation site.

13. The method according to claim 11, comprising the step of adjusting the tension of the guide wire according to wind force acting on the load during a lifting maneuver.

14. The method according to claim 11, comprising the steps of detaching the control wires from the lifting connector; lowering the tension of the guide wires; increasing the tension of a fold-in wire of a fold-in arrangement of a load guiding arrangement to retract an upper traverse; and bringing the crane into a boomed-down position.

15. A load guiding arrangement configured to mount to a crane, the load guiding arrangement including a plurality of load guides, wherein a load guide of the plurality of load guides comprises: a lifting frame having a plurality of holders for holding a component to be raised or lowered, wherein said holders are arranged to hold said component within said lifting frame by said plurality of holders; a guide wire extending from a lower level of the crane to an upper level of the crane; a bridging connector configured to bridge a gap between the guide wire and a control wire, the bridging connector being free to travel along the guide wire and the control wire according to a vertical displacement of the component; and the control wire extending from the upper level of the crane, through the bridging connector to a lifting connector for connecting to the lifting frame, and through the bridging connector again to the lower level of the crane; wherein the bridging connector includes a plurality of pulley wheels, a pulley wheel of the plurality of pulley wheels being arranged to travel along the guide wire; wherein the bridging connector includes two housing plates in an open casing construction, and wherein the housing plates are arranged parallel to each other, and are connected by a number of axles about which the pulley wheels are free to rotate whereby the load can be steadily lifted without any significant lateral displacement, even in strong wind conditions.

Description

BRIEF DESCRIPTION

(1) Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

(2) FIG. 1 shows a crane with a load guiding arrangement;

(3) FIG. 2 shows a bridging connector of a load guide in one embodiment of a load guiding arrangement;

(4) FIG. 3 illustrates a detail of an embodiment of the load guiding arrangement;

(5) FIG. 4 illustrates a further detail of an embodiment of the load guiding arrangement;

(6) FIG. 5 shows a fold-in arrangement of an embodiment of the load guiding arrangement;

(7) FIG. 6 shows an exemplary situation during a lifting procedure using a crane equipped with a load guiding arrangement; and

(8) FIG. 7 shows an alternative embodiment of a bridging connector.

(9) In the diagrams, like numbers refer to like objects throughout. Objects in the diagrams are not necessarily drawn to scale.

DETAILED DESCRIPTION

(10) FIG. 1 shows a crane 2 with a load guiding means 1 according to embodiments of the invention. The crane 2 is realized for mounting to an installation vessel for offshore wind turbine assembly, and can lift a load 4 (indicated by the dotted line) to a required height. The crane 2 can be transported to the installation site in a boomed-down position, and can be boomed up into an essentially ‘vertical’ position as shown here, with a small degree of tilt. The load guiding means comprises a pair of load guides, one on each side of the crane 2, each with a guide wire 31 and a control wire 32 connected between anchor points 39_U, 39L, in this case an upper traverse 39_U and a lower traverse 39_L. In this embodiment, the upper traverse 39_U and lower traverse 39_L are mounted to an open framework of the crane 2. The guide wire 31 and tag wire 32 of a load guide are united by a bridging connector 33 that is free to slide or roll along the guide wire 31.

(11) Before commencing a lifting procedure, the load 4 is attached to the crane 2 by means of a lifting wire 20. A tag wire 32 is looped over a lifting connector 34 of the load guiding means, mounted to the load 4. Tension in the guide wires 31 and tag wires 32 is increased until these are taut. The load lifting wire 20 is retracted using a lifting winch (not shown) to lift the load upwards. As the load 4 is lifted, the bridging connectors 33 displace horizontal tag line portions 32_U, 32_L between the lifting connector 34 and the bridging connector 33 as the load is being displaced vertically. This is illustrated in FIG. 2, which shows one embodiment of a bridging connector 33 of a load guide 3. In this realization, the bridging connector 33 comprises two flat plates 330 arranged parallel to each other. Three pulley wheels 310, 320_U, 320_L are mounted between the plates 330 so that the pulley wheels 310, 320_U, 320_L are free to rotate. The size of the housing plates 330 and the positions of the pulley wheels 310, 320_U, 320_L are chosen to bridge a gap G between guide wire 31 and tag wire 32. A first pulley wheel 310 is arranged to travel along the fixed guide wire 31 during a vertical displacement D.sub.V of the load. The other two pulley wheels 320_U, 320_L are arranged to displace the upper and lower horizontal tag wire portions 32_U, 32_L according to the vertical displacement D.sub.V. Since the tag wire 32 is under tension during a lifting procedure, upper and lower horizontal tag line portions 32_U, 32_L will always lie closely over the respective pulley wheels 320_U, 320_L.

(12) FIG. 3 shows the essential components 31, 32, 33, 34 of the load guiding arrangement 1 according to embodiments of the invention. The tag line 32 is free to travel over a part of a lifting connector 34 of the load 4. Here, the load 4 is held in a lifting frame 40 to which the lifting connector 34 is mounted. This comprises a pulley wheel 340 over which the tag line 32 has been looped. This pulley wheel 340 is also free to rotate, so that the tag wire 32 can freely pass through the lifting connector 34 and the bridging connector 33 as the load is lifted or lowered through a vertical displacement D.sub.V.

(13) FIG. 4 shows a lower traverse 39_L to which are mounted a guide wire winch 31_W for paying out and retracting a guide wire 31, and a tag wire winch 32_W for paying out and retracting a tag wire 32. While it is advantageous to have the guide wire winch 31_W near the body of the crane 2, so that the guide wire 31 is always close to the crane 2, the tag wire winch 32_W itself could, in an alternative embodiment, be positioned elsewhere, for example on the ground. The bridging connector (not shown) will always ensure that the tag line can guide the load in the desired manner. This embodiment also shows remote control means having remote control interface modules 71, 72 in the winches 31_W, 32_W for receiving instructions from a remote control system 73. The winches 31_W, 32_W are also connected to a power supply (not shown), and the remote control interface modules 71, 72 can actuate the winches 31_W, 32_W according to the instructions received.

(14) FIG. 5 shows an embodiment of the load guiding arrangement according to embodiments of the invention, with a fold-in arrangement 35, 35_W for folding in a hinged upper traverse 39_U. This is secured to the crane 2 by means of hinges 390 that only allow movement over the angular region indicated by the arrows. The ends of the tag wires and guide wires (only one wire is shown here for the sake of clarity) are fixed to the outer corners of the upper traverse 39_U. A fold-in wire 35 extends from the outer corners of the upper traverse 39_U towards the crane body. In this embodiment, the fold-in wire 35 extends down to the base of the crane and to a fold-in winch 35_W which is realized to retract or pay out the fold-in wire, as required. When the tag wires and guide wires are under tension, a downward force acts on the upper traverse 39_U. When the tension in the tag wires and guide wires has been slackened, there is no longer any downward force acting on the upper traverse 39_U. Then, in order to fold in the upper traverse 39_U, the fold-in winch 35_W can be actuated to retract the fold-in wire 35. This causes the hinged upper traverse 39_U to fold up and in towards the crane body. The crane 2 can then be boomed down for transport. To boom up the crane, the above steps can be carried out in the reverse order.

(15) FIG. 6 shows an exemplary situation during a lifting procedure using a crane 2 equipped with elements 31, 32, 33, 34 of a load guiding means according to embodiments of the invention. Here also, for the sake of clarity, only one wire is shown to represent the guide and control wires 31, 32. The crane is mounted to an installation vessel 5 and can be brought into a boomed-up position as shown here. The crane 2 is being used to lift a rotor blade 4 into position for mounting to a hub 60 of a wind turbine 6 at an offshore location. The rotor blade 4 is held by a plurality of holders 36, 36a in a lifting frame 40 which is suspended from a lifting cable 20. The load guides of the lifting arrangement serve to maintain a specific orientation of the rotor blade 4 throughout the lifting procedure, even if wind forces F.sub.W acting on the load 4 would otherwise deflect it from this specific orientation. Here, the wind forces are shown symbolically by arrows, and it will be clear that these wind forces act on any object in the path of the wind. In this way, the lifting procedure can be carried out quickly and efficiently, and the rotor blade 4 can be mounted safely to the hub 60. The hub 60 itself and the nacelle 61 to which it is attached can also have been lifted into place onto the wind turbine tower 62 in previous lifting maneuvers using a crane 2 with the load guiding means according to embodiments of the invention.

(16) FIG. 7 shows an alternative realization of a bridging connector 33. Here, the bridging connector 33 comprises two pulley wheels 310 for travelling along the guide wire 31. The bridging connector 33 is longer than the embodiment shown in FIG. 2, so that the upper and lower pulley wheels 320_U, 320_L are further apart. This allows the tag line portions 32_U, 32_L to follow a slanted path over a pulley wheel 340 of the load connector. This embodiment may be preferred if the guide wire 31 and tag wire 32 follow a sloped crane orientation.

(17) Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

(18) For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements. The mention of a “unit” or a “module” does not preclude the use of more than one unit or module