DK178824B1

DK178824B1 - Clamping Device

Info

Publication number: DK178824B1
Application number: DKPA201500117A
Authority: DK
Inventors: Bjarne Sørensen
Original assignee: Ah Ind As
Priority date: 2015-03-02
Filing date: 2015-03-02
Publication date: 2017-02-27
Also published as: WO2016138907A1; DK201500117A1

Abstract

A clamping device for handling a wind turbine blade is disclosed. The clamping device comprises attachment means (8, 8', 8'', 8''') configured to detachably attach the clamping device (2) to a wind turbine blade (50). The clamping device (2) is configured to be opened and closed. The clamping device (2) comprises one or more insert members (8, 8', 8'', 8''') that fit the outer geometry of the wind turbine blade (50). The insert members (8, 8', 8'', 8''') constitute a space (10) with an interlocking geometric shape configured to prevent the clamping device (2) from moving when the clamping device (2) is closed and attached to a wind turbine blade (50). The portion of the insert members (8, 8', 8'',8''') that is configured to bear against the wind turbine blade (50) comprises a resilient component (90) having a coefficient of static friction, ìs, of such a magnitude that a significant friction force (Ffriction) is provided between the outside surface of the wind turbine blade (50) and the insert members (8, 8', 8'', 8''').

Description

damping Device Field of invention

The present invention generally relates to a damping device for i handling wind turbine blades. The invention more particularly relates to a clamping device for handling wind turbine blades during "rotor lift" and "bonny lift", where two blades are lifted in a "bunny ear" configuration. i Prior art

As wind turbine blades are getting bigger, the stress during handling of the blades is an important issue. During handling, the blades are under influence of great forces and thus subject to high peak loads. When these forces are transferred to the blades on small contact areas, the i pressure in these areas may exceed the allowable pressure limit. WO 2010124744 A1 discloses a system for lifting a blade of a wind turbine. The system comprises a yoke device adapted for being lifted by a crane. The system comprises an upper bracket device and a lower i bracket device mounted to the yoke device for holding the blade. The upper bracket device is adapted for engaging a first section of the blade and the lower bracket device is adapted for engaging a second section of the blade. The central portion of the blade is, however, not supported by the system. Therefore, deformations are expected to occur in the i central portion of the blade. This is critical especially when handling large blades. Accordingly, it is desirably to have an improved system, in which the peak load on the blade can be minimised WO 03100249 A1 discloses a methods and gripping unit for handling i wind turbine blades and mounting said blades on a wind turbine. The gripping unit comprises clamping jaws configured to be pressed towards the blade in order to fix the blade to the gripping unit. This gripping unit is, however, not suitable for large wind turbine blades as it exceeds the allowable compression force. Accordingly, it would be desirable to have i an alternative device for handling large wind turbine blades. US 2012032125 Al discloses a device for handling a rotor blade of a wind turbine. The device includes a frame which defines an inner space for at least partially accommodating the rotor blade. The device further i includes a blade support which is arranged in the inner space and mounted to the frame, and a first lever arm. The first lever arm is pivotably mounted to the frame and includes a retaining end arranged in the inner space and an actuator end which is movable to rotate the first lever arm so that the rotor blade is retained between the blade i support and the retaining end. This device is, however, not suitable for large wind turbine blades as the forces exerted towards the blades by the blade support exceed the allowable compression force. Therefore, it would be desirable to have an alternative device for handling large wind turbine blades. EP 2345811 discloses a clamp for clamping a wind turbine blade. The clamp comprises a first contact surface adapted to contact a portion of the surface of the blade and a second contact surface adapted to contact another portion of the surface of the blade. The second contact i surface is displaceable relative to the first contact surface.

This clamp is not suited for handling large wind turbine blades because of the large peak loads (pressure) that occur during handling of blades when using this clamp.

Therefore, there is need for an alternative way of handling large wind turbine blades.

It is an object of the present invention to provide a clamping device i suitable for handling large wind turbine blades during rotor lifts and bonny lifts.

Summary of the invention

The object of the present invention can be achieved by a clamping device as defined in claim 1. Preferred embodiments are defined in the dependent sub claims, explained in the following description and i illustrated in the accompanying drawings.

The clamping device according to the invention is a clamping device comprising attachment means configured to detachably attach the clamping device to a wind turbine blade. The clamping device is i configured to be opened and closed. The clamping device comprises one or more insert members that fit the outer geometry of the wind turbine blade. The insert members constitute a space with an interlocking geometric shape configured to prevent the clamping device from moving, with respect to the wind turbine blade when the clamping i device is closed and attached to a wind turbine blade. The portion of the insert members that is configured to bear against the wind turbine blade comprises a resilient component which has a coefficient of static friction, ps, of such a magnitude that a significant friction force is provided between the outside surface of the wind turbine blade and the i insert members, wherein the clamping device surroundingly encases the portion of the wind turbine blade that is received by the clamping device.

Hereby, the normal force and the resulting pressure exerted to the i lower portion of the wind turbine blade are reduced significantly compared to the prior art clamping devices.

By providing the portion of the clamping device that abuts the wind turbine blade with a resilient material (e.g. an elastomer) with high i friction, it is possible to provide high friction between the clamping device and the wind turbine blade. Hereby, the reaction force on the lower portion of the wind turbine blade is reduced. Accordingly, the forces are distributed onto a large area which allows for the pressure load to be significantly reduced. Hereby, the risk of deformation of and i damage to the wind turbine blade can be minimised.

The attachment means are the means required to attach the clamping device to the blade.

By the term "detachably attach the clamping device to a wind turbine blade" is meant that the clamping device is configured to be attached to the blade and to be detached afterwards. i The clamping device is configured to be opened and closed. This means that an opening and/or access is created in/to the clamping device when open, whereas the opening and/or access is reduced or eliminated when the clamping device is closed. i By the term "fit the outer geometry of the wind turbine blade" is meant that the geometry of the insert members corresponds to the outer geometry of the wind turbine blade". In this way, the pressure can be reduced as the forces involved are distributed onto a larger area than when using the prior art clamping devices.

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It may be an advantage that the insert members constitute a closed ring enclosing the wind turbine blade.

By the term "an interlocking geometric shape" is meant a shape that is i configured to provide a firm attachment when being used. This means that the geometry of the insert members and the contact area of the blade are of such a nature that the clamping device is prevented from moving, with respect to the wind turbine blade when the clamping device is closed.

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By the term "significant friction force" is meant friction forces of a magnitude sufficient to ensure that the portion of the wind turbine blade in contact with the clamping device is kept in contact with the clamping device.

It may be an advantage that the insert members have a shape that ensures that the major portion of the outer surface area of the insert members is in contact with the blade when the clamp is closed and attached to the blade.

It may be beneficial that the clamping device surroundingly encases the portion of the wind turbine blade that is received by the clamping device. i Hereby, it is possible to distribute the forces onto a large area so that the pressure load can be significantly reduced in order to minimize the risk of deformation and damage to the wind turbine.

It may be beneficial that the insert members of the clamping device i bear against at least 60% of the surface of the portion of the wind turbine blade that is received by the clamping device.

It is preferred that the insert members of the clamping device bear against at least 80% of the surface of the portion of the wind turbine i blade that is received by the clamping device.

In a preferred embodiment according to the invention, the insert members of the clamping device bear against at least 90% of the surface of the portion of the wind turbine blade that is received by the i clamping device.

In another embodiment according to the invention, the insert members of the clamping device bear against at least 95% of the surface of the portion of the wind turbine blade that is received by the clamping i device.

In yet another embodiment according to the invention, the insert members of the clamping device bear against at least 98% of the surface of the portion of the wind turbine blade that is received by the i clamping device.

It may be an advantage that the clamping device comprises a frame with an upper portion and one or more members that are rotatably or slidably mounted to the upper portion.

Hereby, it is achieved that the frame can be opened either by rotation or translation of one or more members. Such opening may ease detachment of the clamping device. The prior art clamping devices are often difficult to detach from the wind turbine blade as they stick to the i surface of the wind turbine blade. The clamping device according to the invention is easy to detach as the frame is configured to be opened either by rotation or translation of one or more members.

It may be beneficial that the clamping device comprises a lifting frame i rotatably mounted to the upper portion of the frame, where the lifting frame is configured to be attached to one or more sling members.

Hereby, it is possible to keep the clamping device attached to a crane by means of at least one sling and still be able to change the orientation i of the frame relative to the lifting frame. This option may be of great importance during e.g. rotor lift and bonny lift.

It may be advantageous that the frame has a longitudinal axis and that the lifting frame has a longitudinal axis and that the clamping device is i configured to be arranged in a first position, in which the longitudinal axis of the frame and the longitudinal axis of the lifting frame extend parallel to each other. It may also be an advantage that the clamping device is configured to be arranged in a second position in which a predefined angle is provided between the longitudinal axis of the frame i and the longitudinal axis of the lifting frame. The predefined angle may be e.g. within the range of 80- 90 degrees.

Hereby, it is possible to attach the clamping device to a horizontally oriented wind turbine blade and assist the wind turbine blade to which i the clamping device is attached during e.g. rotor lift or bonny lift, where the wind turbine blades no longer extend horizontally.

It may be an advantage that the angle between the longitudinal axis of the frame and the longitudinal axis of the lifting frame can be set and i changed according to specific requirements. In this manner, the clamping device can be used to handle wind turbine blades of different types and sizes.

It may be an advantage that the clamping device comprises means for i mechanically limiting the range of motion of the lifting frame relative to the frame. These means may be a stop member provided on the upper portion of the frame. The means may be configured to receive a pin.

It may be an advantage that the frame has a stop member configured i to engage with a corresponding pin slidably attached to the frame member, optionally within a pin housing attached to the frame member. Activation of the pin may be carried out by means of an electrical actuator. i It may be an advantage that the lifting frame is rotatably attached to the frame by means of a left joint and a right joint.

It may be beneficial that the lifting frame is rotatably mounted about an axis extending perpendicular to the longitudinal axis of the frame.

Hereby, it is possible to keep the lifting frame vertically oriented and still change the orientation of the frame.

It may be advantageous that the insert members are detachably i mounted. When the insert members are detachably attached any of them may be replaced in order to make the clamping device fit to a wind turbine blade of a different size and/or geometry.

It may be an advantage that the clamping device is configured to i receive insert members of different geometries and thicknesses.

Hereby, it is possible to adapt the clamping device to specific demands and specific wind turbine blades (specific sizes and shapes). i It is possible to use the same clamping device to handle various types of wind turbine blades.

It may be beneficial that the insert members comprise at least an outer layer of a resilient material such as a rubber material or another i suitable material e.g. an elastomer.

Hereby, the insert members are configured to take up small tolerances and deviations due to thermal expansion. i It may be beneficial that the clamping device comprises a front portion configured to receive a plurality of front inserts and a back portion configured to receive a plurality of back inserts. Such construction provides a reliable and robust clamping device. i It may be an advantage that the clamping device comprises an upper portion, in which an upper intermediate member is provided between a left upper front frame part and a left upper back frame part and in which an intermediate member is provided between a right upper front frame part and a right upper back frame part, where the clamping i device comprises a left member having a lower intermediate member extending between a left lower back frame part and a left lower front frame part, where the upper portion comprises a right member having a lower intermediate member extending between a right lower back frame part and a right lower front frame part.

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Hereby, it is possible to provide insert members of various thicknesses in the clamping device.

It may be an advantage that the clamping device comprises a number i of actuators configured to rotate the one or more members (e.g. the lifting frame) relative to the upper portion, and that the clamping device comprises means for controlling the actuators.

Hereby, an accurate and controllable rotation of the one or more i members (e.g. the lifting frame) relative to the upper portion of the frame can be provided.

It may be an advantage that the actuators are electrical actuators. i It may be an advantage that the clamping device comprises means for wirelessly controlling the clamping device. The clamping device may be provided with a control box containing means for communicating wirelessly with a wireless remote control, so that the clamping device may be controlled from ground level.

Hereby, it is possible to control the clamping device from ground level while the clamping device is mounted on a wind turbine blade positioned above ground level. i It may be beneficial that an intermediate member is provided between the front portion and the back portion.

It may be an advantage that the clamping device comprises an upper portion configured to clamp at least a portion of the thickest half of the i blade inserted into the space created by the insert members, and that one or more insert members are configured to clamp at least a portion of the thinnest half of the blade inserted into the space.

It may be beneficial that the clamping device comprises two members i rotatably or slidably mounted to the upper portion, and that the clamping device comprises means for locking the two members to one another when the clamping device is closed. Hereby, the clamping device is prevented from being unintendedly opened during operation. Consequently, a secure and reliable clamping device can be achieved.

It may be an advantage that the clamping device is provided with insert members adapted to receive a wind turbine blade which is provided with wind turbine blade vortex members. The insert members may be provided with tracks or recesses configured to receive the wind i turbine blade vortex members.

Description of the Drawings

The invention will become more fully understood from the detailed description given herein below. The accompanying drawings are given i by way of illustration only, and thus, they are not limitative of the present invention. In the accompanying drawings:

Fig. 1 shows a perspective view of a clamping device according to the invention seen from above; i Fig. 2 shows a side view of a clamping device according to the invention;

Fig. 3 a) shows a front view of a clamping device according to the invention;

Fig. 3 b) shows a side view of a clamping device according to the i invention;

Fig. 3 c) shows a perspective view of a clamping device according to the invention seen from below;

Fig. 4 a) shows a perspective view of a clamping device according to the invention seen from above; i Fig. 4 b) shows another perspective view of a clamping device according to the invention seen from above;

Fig. 4 c) shows a perspective view of an open clamping device according to the invention;

Fig. 5 a) shows a schematical view of a clamping device according i to the invention being mounted on a wind turbine blade;

Fig. 5 b) shows a schematical view of the clamping device shown in Fig. 5 a) mounted on a wind turbine blade;

Fig. 6 shows a schematical view of how the clamping device according to the invention is applied to carry out a rotor . lift;

Fig. 7 shows a perspective view of an open clamping device according to the invention;

Fig. 8 shows a close-up view of a clamping device according to the invention; i Fig. 9 shows a front view of a clamping device according to the invention adapted to receive wind turbine blades oriented differently and

Fig. 10 shows how the clamping device according to the invention applies significantly less force to the blade than the prior i art clamping devices.

Detailed description of the invention

Referring now in detail to the drawings for the purpose of illustrating i preferred embodiments of the present invention, a clamping device 2 according to the invention is illustrated in Fig. 1.

Fig. 1 illustrates a perspective view of a clamping device 2 seen from above. The clamping device 2 comprises a frame 40 which has a left i frame member 41 which is rotatably mounted to a frame portion comprising an upper front frame part 3 and an upper back frame part 4.

The left frame member 41 is configured to rotate about the axis of a hinge 28 in order to open the clamping device 2 at its bottom end 30. i The left frame member 41 comprises a lower front frame 5 and a lower back frame 6. An insert member 8 is arranged within and kept in place by the left frame member 41.

The frame 40 also comprises a right member 43 which is rotatably i mounted to an upper frame portion comprising an upper front frame part 3' and a upper back frame part 4' (see Fig. 3 c).

Like the left frame member 41, the right frame member 43 is configured to rotate about the axis X' (see Fig. 3 c) of its hinge 28' in • order to open the clamping device 2 at its bottom end 30. The right frame member 43 comprises a lower front frame 5' and a lower back frame 6' (shown in Fig. 3 c). An insert member 8" is arranged within and kept in place by the left frame member 43. i The upper front frame part 3, the upper front frame part 3', the lower front frame 5 and the lower front frame 5' are provided with holes 11.

The left frame member 41 and the right frame member 43 are brought together as the clamping device 2 is closed. The left frame member 41 i and the right frame member 43 abut in a joint 14'.

The upper portion 66 of the frame 40 comprises a left upper front frame part 3 and a left upper back frame part 4 housing an insert member 8'. The upper portion 66 of the frame 40 also comprises a right upper front i frame part 3' and a right upper back frame part 4 (which is shown in Fig. 3 c). An insert member 8" is fixed within the right upper front frame part 3' and the right upper back frame part 4.

The adjacent insert members 8' and 8" abut in a joint 14.

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The left frame member 41 and the right frame member 43 abut the upper portion 66 of the frame 40 in joints 12 and 12', respectively.

The insert members 8, 8', 8", 8'" are configured to fit the geometry of a i wind turbine blade clamped by the clamping device (see Fig. 5 b). The insert members 8, 8', 8", 8'" comprise a resilient outer layer (e.g. made from a rubber material) so that the insert members 8, 8', 8", 8'" are capable of taking up tolerances while clamping a wind turbine blade. i A space 10 is provided between the insert members 8, 8', 8", 8'". This space 10 is configured to receive a wind turbine blade (see Fig. 5). A lifting frame 42 is rotatably attached to the frame 40 by means of a left joint 34 and a right joint 34' (see Fig. 3). The lifting frame 42 i comprises a left frame member 16 and a right frame member 16' extending parallel to each other. The left frame member 16 and the right frame member 16' are mechanically connected by a cross member 18. An attachment member 24 provided with a bore 26 is attached to the top portion of the left frame member 16. A similar attachment i member 24' equipped with a bore 26' is attached to the top portion of the right frame member 16'. The attachment members 24, 24' are configured to be attached to a sling as illustrated in Fig. 5 and Fig. 6.

On the top of the frame 40, a battery 22 is arranged. Next to the i battery 22, a control box 20 is arranged. The battery 22 and the control box 20 are configured to be used when the clamping device 2 has to be opened or closed or when the lifting frame 42 has to be rotated relative to the frame 40 (as illustrated in Fig. 2). i Although not shown, the clamping device 2 comprises means for opening and closing the clamping device 2 and for rotating the lifting frame 42 relative to the frame 40. These means may be electrical actuators (not shown). The control box 20 may be applied to activate the electrical actuators and the battery 22 may supply the electrical i power to the electrical actuators. It is also possible to apply hydraulic means to open and close the clamping device 2.

It is preferred that the control box 20 comprises a communication unit including an aerial (not shown) configured to communicate with a i wireless remote control. Thus, the clamping device 2 can be operated wirelessly from the ground while being used above ground level e.g. during rotor lift.

Fig. 2 illustrates a side view of a clamping device 2 corresponding to the i one shown in Fig. 1. The clamping device 2 comprises a frame 40 and a lifting frame 42. The frame 40 has been rotated about the joint 34'. Accordingly, there is a non-zero angle β between the longitudinal axis L of the lifting frame 42 and the longitudinal axis Q of the frame 40. The lifting frame 42 comprises a cross member 18 and an attachment i member 24.

The frame member 16' bears against the plate member 38 which limits the range of motion of the frame member 16' and thus the lifting frame 42. The plate member 38 functions as a stop.

The frame 40 has a stop member 36 configured to engage with a corresponding pin that is slidably attached to the frame member 16' within the pin housing 64 which is attached to the frame member 16'. When the longitudinal axis Q of the frame 40 and the longitudinal axis L i of the lifting frame 42 are parallel (corresponding to β=0), the pin (not shown) in the pin housing 64 can be inserted into the stop member 36 and hereby lock the lifting frame 42 relative to the frame 40.

Activation of the pin may be carried out by means of an electrical i actuator (not shown). The clamping device 2 comprises a control box 20 and a battery 22 arranged on the top of the frame 40.

The rotation of the frame 40 relative to the lifting frame 42 may be carried out by means of one or more electrical actuators (not shown).

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Fig. 3 a) illustrates a front view of the clamping device 2 shown in Fig. 1 and in Fig. 2. Fig. 3 b) illustrates a side view of the clamping device 2, whereas Fig. 3 c) illustrates a perspective view of the clamping device seen from below. The clamping device 2 comprises a lifting frame 42 i with a cross member 18 attached to two parallel frame members 16, 16' which are rotatably attached to a frame 40 by means of two joints: 34 with the axis of rotation Y and 34' with the axis of rotation Y'. Two attachment members 24, 24' are provided at the top portion of the frame members 16, 16'.

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The frame 40 comprises a left upper front frame part 3, a right upper front frame part 3', a left upper back frame part 4 and a right upper back frame part 4' which constitute the upper portion 66 of the frame 40. An insert member 8' is fixed within the left upper front frame part i 3, and another insert member 8" is fixed within the right upper front frame part 3'. Other insert members (not shown) are provided within the left upper back frame part 4 and the right upper back frame part 4'. i An upper intermediate member 7 is provided between the left upper front frame part 3 and the left upper back frame part 4. Similarly, an intermediate member 7' is provided between the right upper front frame part 3' and the right upper back frame part 4'. i The frame 40 comprises a left member 41 which is rotatably attached to the upper portion 66 of the frame 40 by means of a first hinge 28 with the rotational axis X and a second hinge 28' with the axis of rotation X'. The frame 40 also comprises a right member 43 which is rotatably attached to the upper portion 66 of the frame 40.

The left member 41 comprises a left lower back frame part 6 and a left lower front frame part 5 and a lower intermediate member 9 extending between the left lower back frame part 6 and the left lower front frame part 5. An insert member 8 is housed in the left lower front frame part I 5.

The right member 43 comprises a right lower back frame part 6' and a right lower back frame part 5' and a lower intermediate member 9' extending between the right lower back frame part 6' and the right i lower front frame part 5'. An insert member 8"' is housed in the right lower front frame part 5'.

Although it cannot be seen from Fig. 3, insert members (not shown) are housed in the left lower back frame part 6, the right lower back frame i part 6' as well as in the left upper back frame part 4 and in the right upper back frame part 4'.

It is possible, at least partly, to fill out the space within the intermediate members 7, 7', 9, 9' by replacing the insert members 8, 8', 8", 8"' with i thicker insert members. The insert members 8, 8', 8", 8'" have a thickness d that is smaller than half the total thickness D of the frame 40.

By replacing the insert members 8, 8', 8", 8'" with thicker insert i members and thereby, at least partly, filling out the space within the intermediate members 7, 7', 9, 9', a larger contact surface for receiving the wind turbine blade is achieved. Hereby, the pressure applied by the clamping device 2 on the wind turbine blade can be reduced. i It is also possible to increase the total thickness D of the frame 40 in order to increase the contact area with the purpose of reducing the pressure applied by the clamping device 2 on the wind turbine blade. A battery 22 and a control box 20 are arranged on the upper portion 66 i of the frame 40.

The frame 40 has a stop member 36 which is adapted to engage with a pin that is slidably attached to the frame member 16' within the pin housing 64 which is attached to the frame member 16'.

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The frame member 16' is configured to bear against the plate member 38 and hereby be stopped as illustrated in Fig. 2.

The clamping device 2 comprises an upper portion 66 configured to i clamp at least a portion of the thickest half A of the blade 50 when inserted into the space 10. The two members 41, 43 are configured to clamp at least a portion of the thinnest half B of the blade 50 when inserted into the space 10. i The clamping device 2 is closed at its bottom end 30, and thus the left frame member 41 and the right frame member 43 are brought together. The left frame member 41 and the right frame member 43 abut in a joint 14'. The adjacent insert members 8' and 8" abut in a joint 14,whereas the left frame member 41 and the right frame member i 43 abut the upper portion 3, 3', 4, 4' of the frame 40 in joints 12 and 12', respectively.

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The clamping device 2 comprises a space 10 configured to receive and clamp a wind turbine blade.

Fig. 4 illustrates three perspective views of a clamping device 2 i according to the invention.

Fig. 4 a) illustrates a perspective view of the clamping device 2 seen from above. The clamping device 2 is closed and arranged in an upright position. The clamping device 2 comprises a lifting frame 42 which is i rotatably attached to a frame 40.

The frame 40 comprises an upper portion 66 and a lower portion comprising a left member 41 and a right member 43 which are rotatably mounted to the upper portion 66. The clamping device 2 is i provided with a space 10 configured to receive and clamp a wind turbine blade.

Fig. 4 b) illustrates another perspective view of the clamping device 2 shown in Fig. 4 a). The clamping device 2 is closed, and the lifting i frame extends almost vertically, whereas the frame 40 extends almost horizontally. Thus, the angle a between the longitudinal axis Q of the frame 40 and the longitudinal axis L of the lifting device 42 is about 90 degrees. The left member 41 and the right member 43 are brought together and locked by a pin (not shown).

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Fig. 4 c) illustrates another perspective view of the clamping device 2 shown in Fig. 4 a) and in Fig. 4 b). The clamping device 2 is open, and the left member 41 has been rotated about 90 degrees clockwise, and the right member 43 has been rotated about 90 degrees anti-clockwise.

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Two sling members 44, 44' are attached to the lifting device 42 and to a main sling 46. The sling 46 is configured to be attached to a crane (see Fig. 5 and Fig. 6). i Fig. 5 a) illustrates a schematical view of a clamping device 2 according to the invention being mounted on a wind turbine blade 50. The clamping device 2 is attached to the wind turbine blade 50 near its tip 52. i The clamping device 2 comprises a left member 41 which is hinged at the upper portion 66 of the clamping device 2. The clamping device 2 also comprises a right member 43 that is hinged at the upper portion 66 of the clamping device 2. i A first sling member 44 and a second sling member 44' are attached to the lifting device 42 and to a main sling 46. The main sling 46 is attached to a crane 48.

Fig. 5 b) illustrates a schematical view of the clamping device shown in i Fig. 5 a). The clamping device 2 is mounted on a wind turbine blade 50. The left member 41 and the right member 43 are brought together, and the clamping device 2 is closed at its bottom end 30.

The crane 48 is ready to lift the wind turbine blade 50 by pulling the i main sling 46 which is attached to the first sling 44 and the second sling 44' both of which are fixed to the lifting frame 42.

Fig. 6 illustrates a schematical view of the clamping device 2 according to the invention being used to handle a wind turbine blade 50 during a I rotor lift.

The rotor 56 is being mounted on a nacelle 62 fixed on the top of a tower 58. A large crane 54 carries a sling 60 that is attached to the rotor and hereby handles the main portion of the load of the rotor and i the three blades 50, 50', 50" attached to the rotor 56.

The clamping device 2 is clamped to the blade 50, and a small sling 46 is attached to the clamping device 2. The small sling 46 is attached to the small crane 48 arranged on the ground close to the tip of the blade i 50.

The clamping device 2 is arranged in a position corresponding to the one shown in Fig. 2 and in Fig. 4 b), where the longitudinal axis L of the lifting frame 42 extends almost vertically, and the longitudinal axis Q of i the frame 40 extends almost horizontally.

Fig. 7 illustrates a perspective view of an open clamping device 2 according to the invention. The clamping device 2 comprises a lifting frame 42 which extends basically perpendicular to the frame 40 of the i clamping device 2. The lifting frame 42 is provided with two attachment members 26, each provided with a through-going bore 26.

The lifting frame 42 is rotatably attached to a frame 40. The frame 40 comprises an upper portion 66. The frame 40 comprises a left member i 41 which is rotatably attached to the upper portion 66 and a right member 43 rotatably attached to the upper portion 66.

The left member 41 has a male member 74 provided with an aperture 72. The male member 74 is configured to engage with a female i member 78 comprising two parallel plate members, each provided with an aperture 70, 70'. The female member 78 is attached to the right member 43, and a pin 68 is slidably attached to the right member 43. The pin 68 is configured to be translated through the two apertures 70, 70' and hereby lock the clamping device 2 when the male member 74 i and the female member 78 engage.

The left member 41 houses a front insert member 8 and a back insert member 15, while the right member 43 houses a front insert member 8'" and a back insert member 15'" having a thickness d. The upper • portion 66 houses a left front insert member 8', a left back insert member 15' and a right front insert member 8" and a right back insert member 15".

These insert members 8, 8', 8", 8'", 15, 15', 15", 15'" are detachably i attached and may be replaced in order to make the clamping device fit a wind turbine blade of a different size or geometry. In Fig. 7, all the insert members 8, 8', 8", 8'", 15, 15', 15", 15'" have basically the same thickness d. i Fig. 8 illustrates a perspective close-up view of a clamping device 2 according to the invention. The clamping device 2 is mounted on a wind turbine blade 50. It can be seen that the insert members 8, 8' fit the outer geometry of the wind turbine blade 50. Accordingly, the insert members 8, 8' constitute a space (not shown) with an interlocking i geometric shape configured to prevent the clamping device 2 from moving when the clamping device 2 is closed.

The clamping device 2 comprises a lifting frame with a frame member 16 which is rotatably attached to the upper portion 66 of the frame 40 i by means of a joint 34. An electrical actuator 80 is attached to the left member 41 and to the upper portion 66. The electrical actuator 80 is configured to rotate the left member 41 relative to the upper portion by means of a hinge 28. i Fig. 9 illustrates a front view of the clamping device 2 which is almost identical to the one shown in Fig. 3 a). The clamping device 2 comprises a lifting frame 42 which is rotatably attached to a frame 40 by means of two joints. i The frame 40 comprises a left member 41 which is rotatably attached to the upper portion of the frame 40. The frame 40 also comprises a right member 43 which is rotatably attached to the upper portion of the frame 40. i The left member 41 comprises a left lower front frame part. The right member 43 comprises a right lower back frame part 5'.

The clamping device 2 comprises insert members 8, 8', 8", 8'" that fit the outer geometry of the wind turbine blade 50 received by the i clamping device 2. The insert members 8, 8', 8", 8"' constitute a space with an interlocking geometric shape configured to prevent the clamping device 2 from moving when the clamping device 2 is closed and attached to a wind turbine blade. i It can be seen that the wind turbine blade 50 (which is cut through to get a better overview) comprises three parallel frame members 84 which constitute an inner structure configured to increase the pressure resistance of the wind turbine blade 50. i It is a major advantage that the clamping device 2 is configured to handle wind turbine blades that are oriented in different directions. The insert members 8, 8', 8", 8"' may constitute a space 10 with a shape as illustrated in Fig. 9 or in Fig. 1-3 depending on the preferred mounting orientation of the wind turbine blade.

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The clamping device 2 according to the invention may be provided with insert members 8, 8', 8", 8'" adapted to receive a wind turbine blade provided with wind turbine blade vortex members. The insert members 8, 8', 8", 8"' may be provided with tracks or recesses configured to i receive the wind turbine blade vortex members.

Fig. 10 a) illustrates a clamping device 2 according to the invention. A wind turbine blade 50 (which has been cut through for illustration purposes) has been inserted into the clamping device 2. The wind i turbine blade 50 comprises three parallel frame members 84 configured to increase the pressure resistance of the wind turbine blade 50.

Due to gravity g, the weight of the wind turbine blade 50 causes a reaction force indicated as a normal force Fnormai (shown by three i arrows). The friction Faction between the outside surface of the wind turbine blade 50 and the inside surface of the clamping device 2 is indicated by three arrows. The friction forces Faction between the outside surface of the wind turbine blade 50 reduce the normal force Fn0rmai and thereby the pressure on the lower portion of the wind turbine blade 50.

Accordingly, the clamping device 2 according to the invention reduces the load on the wind turbine blade 50.

Fig. 10 b) illustrates a prior art clamping device 82 comprising a i levelling member mounted on an arm. The arm is configured to be pressed against a wind turbine blade 50 received by the clamping device 82. During activation of the arm, the levelling member is pressed against the wind turbine blade 50 in order to fix it to the clamping device 82.

In order to maintain the wind turbine blade fixed to the clamping device 82, forces F significantly larger than normal forces Fnormai (illustrated in Fig. 10 a) are required. Accordingly, the use of the prior art clamping device 82 illustrated in Fig. 10 b) requires that the wind turbine blade i can sustain the load applied.

In case the wind turbine blade 50 is large and heavy, it cannot sustain the load required to fix the wind turbine blade 50 to the prior art clamping device 82 as illustrated in Fig. 10 b). However, a clamping i device 2 according to the invention as illustrated in Fig. 10 a) may be used.

Fig. 10 c) illustrates a cross-sectional view of the inner portion of a clamping device 2 according to the invention. The inner portion of the i clamping device 2 comprises four insert members 8, 8', 8", 8"' constituting a surrounding member provided with a space 10 which is configured to receive a wind turbine blade.

The inner portion of the clamping device 2 comprises four insert i member 8, 8', 8", 8'", each comprising a hard base component 92 surrounded by a resilient component 90. The resilient component 90 may be ethylene propylene diene rubber (EPDM), ethylene propylene rubber (EPM) or a polymer like polyurethane (PUR). The resilient component 90 may have a Shore A durometer hardness i within the range of 20-95, e.g. between 30-40. The base component 92 may comprise a metal such as steel.

In one embodiment according to the invention, the hard base component 92 is made from steel, and the resilient component 90 is i made from ethylene propylene diene rubber (EPDM), ethylene propylene rubber (EPM) or a polymer like polyurethane (PUR). The resilient component 90 has a Shore A durometer hardness within the range of 20-95, e.g. between 30-40. i The insert members 8, 8', 8", 8'" constitute a surrounding member that surrounds and encases the wind turbine blade when received within the clamping device 2.

Fig. 10 d) illustrates a prior art clamping device 82' configured to i receive and handle a wind turbine blade 50. The clamping device 82' comprises a support element 88 supporting the upper portion of the blade profile.

The lower portion of the blade profile, however, rests against a support i member 86. The weight of the wind turbine blade 50 causes large reaction forces F exerting a significant load on the lower portion of the profile of the wind turbine blade 50.

When handling large wind turbine blades 50, this load may have a i critical magnitude.

Moreover, the clamping device 82' is not configured to hold the wind turbine blade 50 if the wind turbine blade is tilted.

List of reference numerals 2 - Clamping device 3,3' - Front upper frame part i 4, 4' - Back upper frame part 5, 5' - Front lower frame part 6, 6' - Back lower frame part 7, 7' - Upper intermediate member 8, 8', 8", 8'" - Insert member i 9, 9' - Lower intermediate member 10 - Space 11 - Hole 12, 12' - Joint 14, 14' - Joint i 15, 15', 15", 15'" - Insert member 16, 16' - Frame member 18 - Cross member 20 - Control box 22 - Battery i 24 - Attachment member 26, 26' - Bore 28, 28' - Spring 30 - Bottom end 32 - Light indicators i 34, 34' - Joint 36 - Stop member 38 - Plate member 40 - Frame 41 - Left member i 42 - Lifting frame 43 - Right member 44, 44' - Sling member 46 - Sling 48 - Crane i 50, 50', 50" - Blade 52 - Tip 54 - Crane 56 - Rotor i 58 - Tower 60 - Sling 62 - Nacelle 64 - Pin housing 66 - Upper portion i 68 - Pin 70, 70' - Aperture 72 - Aperture 74 - Male member 76 - Actuator i 78 - Female member 80 - Actuator 82, 82' - Prior art clamp 84 - Frame member 86 - Support member i 88 - Support element 90 - Resilient component 92 - Base component X, X' - Axis Y, Y' - Axis i L, Q - Axis a - Angle β - Angle D - Thickness d - Thickness i A - Thickest half B - Thinnest half F - Force

Ffriction - Frictional force

Fnormal - Normal force

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Claims

A clamping element (2) comprising fasteners (8, 8 ', 8 ", in 8"') configured to removably attach the clamping element (2) to a wind turbine blade (50), which clamping element (2) is configured to being opened and closed, characterized in that the clamping element (2) comprises one or more insertion units (8, 8 ', 8 ", 8'") adapted to the outer geometry of the wind turbine blade (50) and the insertion units (8, 8 ', 8 ", 8 '") is a cavity (10) of interlocking geometric shape configured to prevent the clamping element (2) from moving relative to the wind turbine blade (50) when the clamping element (2) is closed and attached to the wind turbine blade (50), wherein the portion of the insertion units (8, 8 ', 8 ", 8'") configured to support in the wind turbine blade (50) comprises a flexible component (90) having a static coefficient of friction ps, with such strength that a considerable frictional force (Ffriction) is exerted between the outside of the wind turbine blade (50) and into the guide units (8, 8 ', 8 ", 8"'), wherein the clamping element (2) encapsulates the portion of the wind turbine blade (50) received by the clamping element (2).

A clamping element (2) according to claim 1, characterized in that the clamping element (2) comprises a frame (40) with an upper part (66) and one or more elements (41, 43) rotatably or slidably mounted to the upper part (66).

A clamping element (2) according to claim 2, characterized in that the clamping element (2) comprises a lifting frame (42) rotatably mounted on the upper part (66) of the frame (40), wherein the lifting frame (42) is configured to be secured. to one or more loop elements (44, 44 ').

A clamping element (2) according to one of the preceding claims 1-3, characterized in that the frame (40) has a longitudinal axis (Q) and that the lifting frame has a longitudinal axis (L) and that the clamping element (2) is configured to being placed in a first position where the longitudinal axis (Q) of the frame (40) and the longitudinal axis (L) of the frame (42) extend parallel to each other, and that the clamping element (2) is configured to be placed in a second position where a predefined angle (a) is provided between the longitudinal axis (Q) of the frame (40) and the longitudinal axis (L) of the lifting frame (42).

A clamping element (2) according to claim 4, characterized in that the lifting frame (42) is rotatably mounted about an axis (Y, Y ') extending perpendicular to the longitudinal axis (Q) of the frame (40).

A clamping element (2) according to one of the preceding claims, characterized in that the insertion units (8, 8 ', 8 ", 8"') are removably mounted.

A clamping element (2) according to claim 6, characterized in that the clamping unit (2) is configured to receive insertion units (8, 8 ', 8 ", 8"') of different geometry and thickness (d).

A clamping element (2) according to one of the preceding claims, characterized in that the clamping element (2) comprises a front side part (3, 3 ', 5, 5') configured to receive several front side insertion units (8, 8 '). 8 ", 8 '"), and that the clamping element (2) comprises a backside portion (4, 4', 5, 5 ') configured to receive multiple rear insertion units (15, 15', 15 ", 15 '").

A clamping element (2) according to claim 8, characterized in that the clamping element (2) comprises an upper part (66), wherein an upper intermediate element (7) is arranged between a left upper front part of the frame (3) and a left upper rear part of the frame (4), and in which in an intermediate element (7 ') is arranged between a right upper front part of the frame (3') and a right upper rear part of the frame (4 '), the clamping element (2) comprising a left element (41) having a lower intermediate element (9) extending between a left lower back portion of the frame (6) and a left lower front portion of the frame in (5), the upper portion (66) comprising a right element (43) having a lower intermediate member (9 ') extending between a right lower rear portion of the frame (6') and a right lower front portion of the frame (5 ') ·

A clamping element (2) according to claim 2, characterized in that the clamping element (2) comprises a plurality of actuators (76) configured to rotate one or more elements (41, 43) relative to the upper part (66) and the clamping element (2) comprises means (20) for controlling the actuators (80). in

A clamping element (2) according to claim 2, characterized in that the clamping element (2) comprises two elements (41, 43) rotatably or slidably mounted to the upper part (66) and the clamping element (2) comprises means ( 68, 70 '70', 72, 74, 76, 78) for locking two in members (41, 43) together when the clamping member (2) is closed.