WO2011050804A1

WO2011050804A1 - Lifting device for wind turbine equipment or components and method of using same

Info

Publication number: WO2011050804A1
Application number: PCT/DK2010/050273
Authority: WO
Inventors: Mohan Raj Krishnaswamy; Irissappane Vijayasankar
Original assignee: Vestas Wind Systems A/S
Priority date: 2009-10-30
Filing date: 2010-10-18
Publication date: 2011-05-05

Abstract

A lifting device (10) for a component or piece of equipment for a wind turbine generally comprising a frame (12) having a top member (14) and bottom member(16), a screw(30) extending from the top member toward the bottom member, a motor secured to the top member and drivingly coupled to the screw, and a connection member(24). The connection member includes a joint member(42) threadably engaging the screw, at least one extension (44, 46) extending from the joint member and substantially horizontally relative to the screw, and a connector (48) rotatably supported by the at least one extension or joint member and configured to be secured to the heavy item. The lifting device also includes at least one guide member (32, 34) extending between the top and bottom members of the frame and through the extension (s) of the connection member. The guide member (s) prevents rotation of the connection member about the screw so that the connection member moves along the screw to raise or lower the component or piece of equipment.

Description

Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

Technical Field

[0001] The present invention relates to devices and methods for lifting heavy items. More specifically, the present invention relates to devices and methods for lifting wind turbine equipment or components.

Background

[0002] Wind turbines have long been used to convert the kinetic energy of the wind into mechanical energy that rotates the shaft of a generator, thereby producing electricity. Over time, there has been a significant increase in the overall size of these machines and their components. This has made producing and handling the components very challenging.

[0003] For example, some modern-day wind turbines include blades longer than 50 meters. The blades are typically produced by laying materials into moulds configured to form blade shells, curing the materials, and then closing the moulds and bonding the shells together. Thus, the moulds themselves are even larger than the blades and may require some lifting/manipulation during blade production. Indeed, the moulds may even be moved to different places within a factory before, during, or after blade production to optimize the factory layout and production processes.

[0004] Moving the moulds around within a blade factory can be very difficult not only because of their size, but also their weight. A mould for 50-meter or longer blade, for example, may weigh more than 50 tons. Conventional methods for lifting and transporting these moulds involve using overhead factory cranes and, in some cases, mobile cranes to support the overhead cranes. But constructing such cranes to handle these heavy loads is expensive. Moreover, their overall size and room required to operate present challenges as well, particularly for mobile cranes, because the large size of the moulds already limits the amount of available factory space.

[0005] Therefore, alternative devices and methods for lifting such large and heavy items are highly desirable. Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

Summary

[0006] A lifting device for a heavy item, such as a component or piece of equipment for a wind turbine, generally comprises a frame having a top member and bottom member, a screw extending from the top member toward the bottom member, a motor secured to the top member and drivingly coupled to the screw, and a connection member. The connection member includes a joint member threadably engaging the screw, at least one extension extending from the joint member and

substantially horizontally relative to the screw, and a connector rotatably supported by the at least one extension or joint member. At least one guide member extends between the top and bottom members of the frame and through the extension(s) of the connection member. As a result, the at least one guide member prevents rotation of the connection member about the screw so that the connection member is movable along the screw.

[0007] Advantageously, such an arrangement helps limit the loads being transferred to the lifting device to the vertical direction. Without having to withstand large bending moments and other non- vertical forces when lifting an item, the lifting devices can be designed smaller yet still provide advanced lifting capabilities.

[0008] As a further aspect or embodiment, the at least one guide member may comprise first and second guide members positioned on opposite sides of the screw, and the at least one extension may comprise first and second extensions through which the first and second guide members extend. The first and second extensions may be freely received in the joint member and lubricated by supplying lubricant through holes in the joint member. Such an embodiment further facilitates the above- mentioned advantages.

[0009] In another aspect or embodiment, the screw may have a length such that it is suspended from the top member of the frame. A bottom surface of the screw is therefore spaced from the bottom member. Such an arrangement ensures that the screw is placed in tension by the connection member when lifting items, thereby allowing failure criteria to be based on material strength of the screw rather than the integrity of any connection between or support from the bottom member of the frame. Such an arrangement also avoids the buckling loads associated with compression forces. When compressive loads must be taken into account, buckling forces may decrease the load capacity of the screw by the square of its length. Additionally, the weight-to-length ratio is less for tensile members compared to Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

compressive members for the same load-carrying capacity, thereby enabling a smaller, more efficient design.

[0010] A method of lifting a heavy item— in particular a mould for a wind turbine blade— is also disclosed. The method generally comprises coupling a plurality of the lifting devices to the mould at different locations and operating the lifting devices to lift the mould. In one aspect or embodiment, the lifting devices communicate with a control system that distributes loads equally between the lifting devices. This may be a matter of operating the lifting devices in the same manner to displace the connection members the same distance, if the lifting devices are initially secured to the mould at locations selected for an even load distribution. Such a feature helps maximize the lifting capabilities of the lifting devices.

[0011] Additionally, the method may further involve moving the mould to another location while the mould is supported by the lifting devices. The use or need for large, conventional lifting equipment, such as overhead factory cranes, is therefore reduced or eliminated. Indeed, the lifting devices may even be used to load the mould onto or off of a truck with minimal or no support from overhead or mobile cranes.

[0012] These and other aspects, together with their advantages, will become more apparent based on the description below.

Brief Description of the Drawings

[0013] Figs. 1 and 2 are front and rear perspective views of one embodiment of a lifting device.

[0014] Figs. 3A and 3B are perspective views similar to Fig. 1, but with some components being removed for clarity.

[0015] Figs. 4A and 4B are perspective views of one embodiment of a connection member for the lifting device of Fig. 1.

[0016] Fig. 5 is a perspective view showing how a screw of the lifting device of Fig. 1 is received in a bushing.

[0017] Figs. 6 and 7 are perspective views showing one embodiment of a wheel assembly for the lifting device of Fig. 1 in greater detail.

[0018] Fig. 8 is a schematic view of a plurality of lifting devices being used to lift a mould for a wind turbine blade. Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

[0019] Fig. 9 is a perspective view of an alternative embodiment of a lifting device.

[0020] Fig. 10 is a perspective view similar to Fig. 9, but with some components being removed for clarity.

Detailed Description

[0021] Figs. 1 and 2 show one embodiment of a lining device 10 for a heavy item. The lining device 10 is specially designed to handle loads caused by the item and, therefore, has a significant lifting capacity. As will be described in greater detail below, several of the lifting devices 10 may be used to lift components weighing more than 50 tons, such as a mould 100 (Fig. 8) for a wind turbine blade.

[0022] The lifting device 10 generally includes a frame 12 having a top member 14 and bottom member 16, which may be in the form of support plates. Various structural support members 18 and walls 20 are positioned between the top and bottom members 14, 16 to strengthen the frame 12 and/or enclose parts within the frame 12. In the embodiment shown, the frame 12 includes three walls 20 (two sidewalls and one back wall) but leaves an opening 22 on a front side to permit access to a connection member 24. Such an arrangement helps prevent dust and other particles from accumulating within the frame 12, yet still allows the connection member 24 to serve as a connection between the lifting device 10 and heavy item being lifted. And because the connection member 24 is configured to move vertically within the frame 12 to lift the heavy item, such an arrangement also helps prevent foreign objects from interfering with this operation.

[0023] Figs. 3A and 3B illustrate the lining device 10 with the walls 20 of the frame 12 and other features removed for clarity. The structural support members 18 are metal bars arranged between the top and bottom members 14, 16 on opposite sides of the frame 12. Although a particular arrangement of vertical and horizontal bars are shown, it will be appreciated that any arrangement providing sufficient structural support between the top and bottom members 14, 16 may be used. As an additional feature, the structural support members 18 may be removably secured to the top and bottom members 14, 16 to allow easy assembly and disassembly. For example, the structural support members 18 may be secured using conventional fasteners, such as screws or nuts and bolts. To facilitate reassembly, the structural support members 18 on each side of the frame 12 may be removed as assemblies (the bars remaining secured to each other) and stored as such for later use. Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

[0024] Within the frame 12, a screw 30 extends from the top member 14 toward the bottom member 16. Additionally, first and second guide members 32, 34 extend between the top and bottom members 14, 16. The screw 30 and guide members 32, 34 extend through the connection member 24, which moves along the screw 30 when the screw 30 rotates. To this end, the top member 14 of the frame 12 is configured to support a motor (not shown) for rotating the screw 30. The motor is drivingly coupled to the screw 30 via a motor mount 36 and gearbox 38.

[0025] Figs. 4A and 4B illustrate components of the connection member 24 in further detail. In this embodiment, the connection member 24 is an assembly comprised of a joint member 42 through which the screw 30 extends, first and second extensions 44, 46 extending substantially horizontally relative to the screw 30, and a connector 48 (Figs. 3A and 3B). The first and second extensions 44, 46 may be rigidly connected to or freely received in the joint member 42. For example, in the embodiment shown the first and second extensions 44, 46 are shafts extending into the joint member 42 from the first and second guide members 32, 34, which are positioned on opposite sides of the screw 30. More specifically, the first and second guide members 32, 34 extend through end portions of the first and second extensions 44, 46. The opposite end portions of the first and second extensions 44, 46 are freely received in the joint member 42 and may be lubricated by supplying lubricant through holes 50 in the joint member 42.

[0026] The connection member 24 further includes first and second nuts 52, 54 threaded onto the screw 30 and secured to opposite sides of the joint member 42. When the screw 30 is driven by the motor, the interaction between the joint member 42, first and second extensions 44, 46, and first and second guide members 32, 34 prevents the joint member 42 from rotating with the screw 30. As a result, the threaded engagement between the first and second nuts 52, 54 and screw 30 causes the joint member 42 to move up or down along the screw 30 depending on the direction of rotation.

[0027] The vertical movement of the joint member 42 is translated to the heavy item being lifted by the connector 48 (Figs. 3 A and 3B), either directly or indirectly. For example, the connector 48 may be indirectly secured to the heavy item by a linkage (not shown) or some other adaptor designed to facilitate attachment of the lifting device 10. Advantageously, the connector 48 is rotatably supported by the first and second extensions 44, 46 (and/or the joint member 42) so that it has a rotational degree of freedom. Such an arrangement reduces or eliminates the transfer of bending moments from the heavy item to the lifting device 10. In other words, during a lifting operation, all or substantially all of Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

the loads transferred to the lifting device 10 are vertical loads transferred to the screw 30 via the connection device 24.

[0028] If desired, the screw 30 may have a length less than a distance between the top and bottom members 14, 16 of the frame 12. The screw 30 in the embodiment shown, for example, is suspended from the top member 14 and does not contact the bottom member 16. Instead, as shown in Fig. 5, an end portion 60 of the screw 30 is received in a bushing 62 positioned on the bottom member 16. The bushing 62 surrounds the end portion 60, but a gap (not shown) remains between a bottom surface of the end portion 60 and a bottom surface or plane of the bushing 62. Such an arrangement ensures that the screw 30 is always loaded in tension by the vertical loads transferred to the lifting device 10 via connection member 24, which has several design advantages. For example, failure criteria for the screw 30 may be based on material strength without having to consider any support or connection between the screw 30 and bottom member 16, or how the bottom member 16 itself might affect the load capacity of the overall arrangement (as is the case with an arrangement where the screw is loaded in compression). Moreover, the weight-to-length ratio is less for tensile members compared to compressive members for the same load-carrying capacity, thereby enabling a smaller, more efficient design.

[0029] Referring back to Figs. 1 and 2, the lifting device 10 further includes one or more wheel assemblies 70 supporting it on a surface 72. Two wheel assemblies 70 are shown, but any number of wheel assemblies may be used. Additionally, although each wheel assembly 70 is shown as including an actuator 80 and first and second wheels 74, 76 coupled to a support 78, in alternative embodiments each wheel assembly 70 may only include a single wheel coupled to the associated actuator (i.e., one wheel per actuator).

[0030] Figs. 6 and 7 illustrate one of the wheel assemblies 70 in further detail. The actuator 80 is an electric cylinder having a motor 82 that drives a rod 84 extending from a cylindrical housing 86. Other actuators, such as hydraulic cylinders, may alternatively be used. The rod 84 is secured to the support 78 to which the first and second wheels 74, 76 are mounted. Thus, when the rod 84 is driven, there is relative movement between the frame 12 and first and second wheels 74, 76. More specifically, reaction forces cause the frame 12 to move vertically relative to the first and second wheels 74, 76 (and ground surface 72). Guide elements 88 positioned along the length of the sidewall 20 serve as a track Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

for corresponding guided members 90 secured to the support 78. This has the advantage of limiting the degrees of freedom of the support 78 relative to the frame 12 to the vertical direction.

[0031] A method of lifting a heavy item with a plurality of the lifting devices 10 will now be described. Fig. 8 schematically illustrates a mould 100 for a wind turbine blade with a plurality of the lifting devices 10 secured at various locations (e.g., via a linkage and the connection member 24, as discussed above). The mould 100 may be for a blade longer than 50 meters and weigh more than 50 tons. Six lifting devices 10 are shown, although additional lifting devices may be used as part of the method.

[0032] Each lifting device 10 communicates with a central control system 102. To lift the mould 100, the control system 102 sends signals to the lifting devices 10 to activate their motors and rotate their respective screws 30, thereby moving the connection members 24 and mould 100 vertically. In one embodiment, the lifting devices 10 are arranged about the mould 100 such that loads are distributed equally among on the lifting devices 10. This may be achieved by taking the mould profile/weight distribution into consideration when determining the locations for securing the lifting devices 10. Such a lifting method is displacement-driven, with the control system 102 operating the lifting devices 10 in a similar manner so that the connection members 24 move the mould 100 the same distance and maintain the equal load distribution. In alternative embodiments, the lifting method may be load- driven, with the control system 102 receiving feedback from strain gauges or other sensors and operating the individual lifting devices 10 in response to the feedback to maintain an equal load distribution.

[0033] By distributing loads equally, smaller lifting devices are able to meet the demands of the lifting operation. Indeed, the lifting devices 10 may be used to lift the mould 100 more than 1.5 meters even though the lifting devices 10 themselves are relatively small compared to conventional lifting equipment, such as overhead and mobile cranes, used for comparable loads. For example, when in an initial lowered position, the lifting devices 10 may be approximately or smaller than approximately 1 x 1.5 x 2.3 meters and still have the advanced lifting capacities mentioned above.

[0034] Once the mould 100 is raised, it may be transported to another nearby location using the lifting devices 10. For example, if the lifting operation began with the bottom members 16 of the lifting devices 10 positioned on or near the surface 72, the control system 102 may operate the wheel assemblies 70 to raise the frames 12 vertically relative to the surface 72. Advantageously, the control Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

system 102 operates the actuators 80 synchronously to maintain the equal load distribution. The actuators 80 raise the frames a sufficient distance to provide safe clearance between the bottom members 16 and surface 72.

[0035] At this point, the lifting devices 10 themselves or in conjunction with other equipment may be used to move the mould 100 to the desired location. For example, the wheel assemblies 70 may be equipped with drives (not shown) operated by the control system 102 for moving the lifting devices 10 across the surface 72. Alternatively, smaller mobile cranes or other equipment may be used to direct the mould 100 to the desired location with the lifting devices 10 allowing such movement via the wheel assemblies 70. If the mould 100 is to be transported a longer distance, the lifting devices 10 may be used to facilitate loading the mould 100 onto a truck or the like. The lifting devices 10 may even be conveniently transported with the mould— in an assembled or disassembled state— and used to help unload the mould 100 from the truck at the intended destination.

[0036] As can be appreciated, the lifting devices 10 reduce or eliminate the need for large

conventional lifting equipment, such as overhead cranes or high-capacity mobile cranes. Less space is required for the overall lifting operation of heavy items thereby allowing more efficient use of factory space. Moreover, the lifting devices 10 can be produced and operated at a much lower cost than overhead and mobile cranes, thereby saving costs.

[0037] Those skilled in the art will appreciate many variations to the particular embodiment of the lifting device 10 described above. Figs. 9 and 10, for example, illustrate a lifting device 200 according to an alternative embodiment. For the sake of simplicity, the same reference numbers are used in Figs. 9 and 10 to refer to similar elements from the lifting device 10 and only the differences will be described below.

[0038] The lifting device 200 includes a connection member 202 that, unlike the connection member 24, does not include rotatably supported components. The connection member 202 instead includes a first portion 204 configured to be secured to the heavy item being lifted, second and third portions 206, 208 through which the first and second guide members 32, 34 extend, and a fourth portion 210 on an opposite side of the screw 30 from the first portion 204. The first portion 204 is fixed relative to the second and third portions 206, 208 such that the connection member 202 is configured to transfer bending loads from the heavy item to the lifting device 200. Although the first and second guide members 32, 34 may be larger in size to withstand these loads, the lifting device 200 may also include Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

a counterweight 212 coupled to the fourth portion 210 to help counteract the bending moments. The counterweight 212 may be selected according to the load and, if necessary, additional counterweights may be added during a lifting operation. The frame 12 may be designed without a back wall to provide access to the fourth portion 210 of the connection member 202 for these purposes.

[0039] Other variations, such as the lifting device 200 including four wheel assemblies 70 each with a respective actuator 216 and wheel 218, are possibilities already mentioned above. The screw 30 extending all the way to the bottom member 16 of the frame 12 such it transfers compressive loads, and the addition of further guide members 220, are other possible variations. Indeed, the embodiments described above are merely examples of the invention defined by the claims that appear below. Those skilled in the art will appreciate additional examples, modifications, combination of features, and advantages based on the description, yet still falling within the spirit and scope of the invention. For example, some embodiments may only include a single guide member extending through the connection member. The connection member in such embodiments may include a single extension (e.g., extension 44 or 46) extending from the joint member. In other embodiments, like the one shown in Figs. 9 and 10, the lifting device may be used as a stand-alone component to lift items. Accordingly, departures may be made from the details of this disclosure without departing from the scope or spirit of the general inventive concept.

Claims

Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME Claims

1. A lifting device for a heavy item, such as a component or piece of equipment for a wind turbine, comprising:

a frame having a top member and bottom member;

a screw extending from the top member toward the bottom member;

a motor secured to the top member and drivingly coupled to the screw;

a connection member having a joint member threadably engaging the screw, at least one extension extending from the joint member and substantially horizontally relative to the screw, and a connector rotatably supported by the at least one extension or joint member and configured to be secured to the heavy item; and

at least one guide member extending between the top and bottom members of the frame and through the at least one extension of the connection member, the at least one guide member preventing rotation of the connection member about the screw so that the connection member is movable along the screw.

2. A lifting device according to claim 1 , wherein the at least one guide member comprises first and second guide members positioned on opposite sides of the screw, and wherein the at least one extension comprises first and second extensions through which the first and second guide members extend.

3. A lifting device according to claim 1 or 2, wherein the screw freely extends through the joint member, the connection member further comprising:

first and second nuts threaded on the screw and secured to opposite sides of the joint member.

4. A lifting device according to any of the preceding claims, wherein the at least one extension is freely received in the joint member. Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

5. A lifting device according to any of the preceding claims, wherein the screw has a length such that it is suspended from the top member of the frame and has a bottom surface spaced from the bottom member.

6. A lifting device according to any of the preceding claims, further comprising:

a bushing positioned on the bottom member of the frame and at least partially surrounding an end portion of the screw.

7. A lifting device according to any of the preceding claims, wherein the frame further includes walls extending between the top and bottom members and at least one opening between the walls to permit access to the connection member.

8. A lifting device according to any of the preceding claims, further comprising:

one or more wheel assemblies for supporting the lifting device on a surface, the wheel assemblies each having an actuator coupled to the frame for moving the frame vertically relative to the surface.

9. A lifting device according to claim 8, wherein the one or more wheel assemblies comprise:

first and second wheel assemblies positioned on opposite sides of the frame, the first and second wheel assemblies each including first and second wheels spaced apart from each other, a support to which the first and second wheels are mounted, and an actuator coupling the frame to the support.

10. A method of lifting a heavy item, comprising

coupling a plurality of lifting devices according to any of the preceding claims to the heavy item, the lifting devices being coupled to the heavy item at different locations; and

operating the lifting devices to lift the heavy item.

11. A method according to claim 10, wherein the lifting devices communicate with a control system, and wherein operating the lifting devices further comprises:

using the control system to distribute loads equally between the lifting devices. Title: LIFTING DEVICE FOR WIND TURBINE EQUIPMENT OR COMPONENTS AND METHOD OF USING SAME

12. A method according to claim 11 , wherein the plurality of lifting devices are coupled to the heavy item at locations selected based on the geometry and weight distribution of the heavy item to provide an equal load distribution such that the control system operates the lifting devices in a similar manner.

13. A method according to any of claims 10-12, wherein the heavy item weighs more than 50 tons, and wherein the lifting devices are operated to raise the heavy item more than 1.5 meters.

14. A method according to any of claims 10-13, wherein the heavy item is a mould for a wind turbine blade.

15. A method according to claim 14, further comprising:

moving the mould to another location while the mould is supported by the lifting devices.

16. A method according to claim 14 or 15, wherein the lifting devices each include one or more wheel assemblies supporting the lifting device on a surface and having an actuator coupled to the frame, and wherein operating the lifting devices to lift the heavy item comprises:

operating the motors of the lifting devices to rotate the corresponding screws and move the connection members vertically, thereby raising the mould; and

after the mould is raised, operating the actuators of the wheel assemblies to move the frames vertically relative to the surface.

17. A method according to any of claims 14-16, further comprising:

loading the mould onto or off a truck with the lifting devices.