Patent ID: 11932520
Assignee: LIFTRA IP APS
Field: Handling (Mechanical engineering)
Classification: CPC B  F  Y | IPC B  F

Claim 6:
7. A self-hoisting crane according to claim 1, wherein the self-hoisting crane further includes an arm base arranged rotatably about an arm base axis on the pedestal, the arm base axis being vertical in the operational position of the self-hoisting crane, wherein the boom arm is arranged pivotally about a boom arm axis on the arm base, the boom arm axis being horizontal in the operational position of the self-hoisting crane, wherein a linear boom actuator is arranged between the arm base and the boom arm and is displaceable between a retracted position in which the boom arm is lowered in the operational position of the self-hoisting crane and an extended position in which the boom arm is lifted in the operational position of the self-hoisting crane, wherein the arm base is provided with at least one arm base roller adapted to roll on a cable extending from a cable winch on the ground to the hoist block, wherein a hook block end of the boom arm is provided with at least one boom arm roller adapted to roll on a cable extending from a cable winch on the ground to the hoist block, wherein, in the extended position of the linear boom actuator, a centre of gravity of the self-hoisting crane is below a straight line between the respective axes of the at least one arm base roller and of the at least one boom arm roller when the at least one base roller and the at least one boom arm roller roll on their corresponding cables and the linear boom actuator is positioned under the boom arm during hoisting of the self-hoisting crane to the nacelle of a wind turbine.