Gripping device for lifting a preform for a wind turbine blade

1. A gripping device ( 76 ) for lifting a preform ( 98 ) for a wind turbine blade from a preform mould ( 71 ), the gripping device ( 76 ) comprising:

a base frame ( 62 ) comprising one or more pivot connectors adapted for being received in a socket member attached to a wind turbine blade mould;

a plurality of arms ( 78 ) slidably mounted on the base frame ( 62 ), each of the arms ( 78 ) having a proximal end and a distal end;

a plurality of gripping members ( 86 ) for gripping a top surface ( 75 ) of the preform, each of the gripping members ( 86 ) being attached to the distal end of at least one of the arms ( 78 ); and

a plurality of lock members ( 90 ), each of the lock members being engaged with at least one of the arms ( 78 ) for allowing sliding motion of the at least one of the arms ( 78 ) relative to the base frame ( 62 ) in a first direction while preventing sliding motion of the at least one of the arms ( 78 ) relative to the base frame ( 62 ) in a second direction.

2. A gripping device ( 76 ) for lifting a preform ( 98 ) for a wind turbine blade from a preform mould ( 71 ), the gripping device ( 76 ) comprising:

a base frame ( 62 );

a plurality of arms ( 78 ) slidably mounted on the base frame ( 62 ), each of the arms ( 78 ) having a proximal end and a distal end;

a plurality of gripping members ( 86 ) for gripping a top surface ( 75 ) of the preform, each of the gripping members ( 86 ) being attached to the distal end of at least one of the arms ( 78 ); and

a plurality of lock members ( 90 ), each of the lock members being engaged with at least one of the arms ( 78 ) for allowing sliding motion of the at least one of the arms ( 78 ) relative to the base frame ( 62 ) in a first direction while preventing sliding motion of the at least one of the arms ( 78 ) relative to the base frame ( 62 ) in a second direction, wherein the first direction is an upward direction and the second direction is a downward direction.

3. The gripping device ( 76 ) according to claim 2 , wherein the lock member comprises a ratchet or a brake.

4. The gripping device ( 76 ) according to claim 2 , wherein sliding motion of the arms ( 78 ) relative to the base frame ( 62 ) is achieved exclusively by the force of gravity.

5. The gripping device ( 76 ) according to claim 2 , wherein the position of the arms ( 78 ) relative to the base frame ( 62 ) is not controlled by a computer or a control unit.

6. The gripping device ( 76 ) according to claim 2 , wherein the gripping member ( 86 ) is a needle gripper.

7. The gripping device ( 76 ) according to claim 2 , wherein the gripping member ( 86 ) releasably attaches to the preform upon contact with the top surface ( 75 ) of the preform.

8. The gripping device ( 76 ) according to claim 2 , wherein each arm ( 78 ) is slidably arranged in a bracket or fixture mounted on the base frame ( 62 ).

9. The gripping device ( 76 ) according to claim 2 , wherein the base frame ( 62 ) is suspended from a lifting device.

10. The gripping device ( 76 ) according to claim 9 , wherein the lifting device comprises a crane or a hoist.

11. The gripping device ( 76 ) according to claim 2 , wherein the base frame ( 62 ) further comprises one or more pivot connectors adapted for being received in a socket member attached to a wind turbine blade mould.

12. A method of transferring a preform for a wind turbine blade, the method comprising:

suspending a gripping device ( 76 ) over the preform, wherein the gripping device ( 76 ) comprises:

a base frame ( 62 );

a plurality of arms ( 78 ) slidably mounted on the base frame ( 62 ), each of the arms ( 78 ) having a proximal end and a distal end;

a plurality of gripping members ( 86 ) for gripping a top surface ( 75 ) of the preform, each of the gripping members ( 86 ) being attached to the distal end of at least one of the arms ( 78 ); and

a plurality of lock members ( 90 ), each of the lock members being engaged with at least one of the arms ( 78 ) for allowing sliding motion of the at least one of the arms ( 78 ) relative to the base frame ( 62 ) in a first direction while preventing sliding motion of the at least one of the arms ( 78 ) relative to the base frame ( 62 ) in a second direction, and wherein downward movement of one or more of the arms ( 78 ) relative to the base frame ( 62 ) is prevented by the plurality of lock members ( 90 );

lowering the gripping device ( 76 ) towards a top surface ( 75 ) of the preform until one or more of the gripping members ( 86 ) engage the top surface ( 75 ) of the preform;

raising the gripping device ( 76 ) with the engaged preform;

arranging the engaged preform within a wind turbine blade mould; and disengaging the preform.

13. The method of transferring a preform for a wind turbine blade according to claim 12 , wherein one or more of the arms ( 78 ) of the gripping device ( 76 ) are pushed upwards relative to the base frame ( 62 ) by the engaged preform top surface ( 75 ) during the step of lowering the gripping device ( 76 ).

14. The method of transferring a preform for a wind turbine blade according to claim 12 , wherein the vertical position of one or more arms ( 78 ) of the gripping device ( 76 ) relative to the base frame ( 62 ) changes during the lowering step.

15. A method of manufacturing a wind turbine blade part, the method comprising:

manufacturing one or more preforms of a wind turbine blade part in a preform mould ( 71 );

transferring each preform to a blade mould using the method of claim 12 ;

infusing resin into the blade mould; and

curing or hardening the resin in order to form the blade part.