Patent ID: 7699584

Claim:
An actuator for adjusting the pitch angle of a rotor blade ( 2 ) of a wind turbine ( 3 ), which is rotatably mounted on a rotor hub ( 1 ), comprising a first drive element ( 4 ) connectable with the rotor blade ( 2 ), a second drive element ( 5 ) in meshing engagement with said first drive element ( 4 ), as well as a lubricating device ( 6 ) for lubricating the two drive elements ( 4 , 5 ), characterized in that the lubricating device ( 6 ) has a lubricant passage ( 7 ) for the selective supply of lubricant directly to at least one of a portion ( 8 ) of the first drive element ( 4 ) and a portion ( 9 ) of the second drive element ( 5 ), when portions ( 8 , 9 ) are in engagement with each other when the rotor blade ( 2 ) is in its preferred working position, and a supply control means ( 10 ) for controlling the supply of lubricant through said lubricant passage ( 7 ) in dependence on the engagement position of the two drive elements ( 4 , 5 ).