Patent ID: 9009964
Filing Date: 2015-04-21
Classification: B66C,F03D,F05B,Y02E,Y02P,Y10T

Abstract:
1. A wind turbine blade lifting system for lifting a wind turbine blade of a wind turbine, comprising: a crane, the crane having: a lifting device suspended from the bearing wire, the lifting device having: a winch arrangement which is located at the lifting device; a control wire which runs to the winch arrangement for controlling a blade orientation horizontal when lifting the wind turbine blade off a ground; and one or more ropes extending from a top end of the crane boom to a bottom end of the crane boom and connected to the control wire by pulleys, the winch arrangement comprises a first winch and a second winch, the control wire comprises a free length comprising a first branch and a second branch, the first branch comprises a first fraction of the control wire, the second branch comprises a second fraction of the control wire, the first and the second branches are connected directly or indirectly to the crane boom, the first winch controls the free length of the control wire, the second winch controls a distribution of the free length of the control wire to the first fraction and the second fraction, and the control wire comprises an end connected to the first winch and an intermediate section wrapped around the second winch.