US Patent 7789793 Bearing tooth gears for wind turbine applications

A horizontal axis wind turbine includes a vertically extending tower 117 having a rotatable long shaft 121. A bottom end of the long shaft drives an electric generator 122 and a top end of the long shaft is connected to a power output gear assembly of a bearing tooth angle drive 120. The power output gear assembly is engaged with a power input gear in the bearing tooth angle drive 120. The power input gear is connected by a drive shaft 86 through a preferably planetary gear drive 119 to blades 106 of a wind turbine to receive power from the wind turbine and to deliver torque to the long shaft 121 to drive the generator 122. The planetary gear teeth preferably have flat surfaces providing contact with related gear teeth.