SELF-RELEASING LIFTING YOKE FOR WIND TURBINE BLADE INSTALLATIONS AND ASSOCIATED METHOD

A lifting yoke (30) supports and moves a wind turbine blade (20) during installation or service at a wind turbine (10). The lifting yoke (30) includes an elongate support beam (42) configured to be lifted and moved by a crane (32), a support element (96) connected to a first end (48) of the support beam (42), and a cradle support (58) connected to a second end (50) of the support beam (42). The support element (96) wraps around the blade (20) proximate a root end (22), while the cradle support (58) lifts and supports the blade (20) at a location between a center of gravity and a tip end (24) of the blade (20). The cradle support (58) includes a support bed (60) with an upper profiled surface (66) that contacts a downward-facing surface (44b) of the blade (20), and also includes a release device (72) and a brake device (76). The release device (72) disconnects one end (62) of the support bed (60) from the support beam (42) to allow the support bed (60) to pivot away from the blade (20), while the brake device (76) controls and slows the pivotal movement of the support bed (60) over a first portion of pivotal movement, thereby avoiding uncontrolled swinging that could impact the blade (20) again. The lifting yoke (30) is simplified in construction by having actively controlled elements only at the release device (72) and brake device (76), while providing improved lifting support for blades (20) that avoids localized points of high stress that can occur when lifting blades (20) with slings.