Patent ID: 8360721

Claim:
A stiff in-plane gimbaled rotor head for a rotorcraft, comprising: an elongated, vertically extending rotor shaft having an axis of rotation; a center hub disposed at an upper end of and rotationally driven by the rotor shaft; an outer hub surrounding and coupled to the center hub through a spherical main gimbal bearing for conjoint rotation with the center hub and such that the outer hub is also capable of an angular range of gimbaling movement relative to the center hub; an elongated, radially extending blade having an airfoil cross-section and an inboard end coupled to the outer hub; a constant velocity joint coupling driving torque from the rotor shaft to the blade through the center and outer hubs such that, during rotation of the blade about the axis of rotation of the rotor shaft, the rotational velocity of the blade about the axis of rotation remains substantially constant during gimbaling movements of the outer hub relative to the inner hub and a blade pitch control mechanism, including: a pitch arm having an inboard end rigidly coupled to the inboard end of a pitch control shaft of the blade and an opposite outboard end; a horizontally extending pitch control cross link having a first end pivotably coupled to the outboard end of the pitch arm and an opposite second end pivotably coupled to a first arm of a pivotally mounted bell-crank; and, a vertically extending pitch link having an upper end connected to a second arm of the bell-crank.