Abstract: A rotary travel limit stop is provided for the purpose of providing positive mechanical stops for rotating machinery. Second and third rotatable members are arranged in gear mesh relation with a first rotatable member. The second and third rotatable members are provided with unequal numbers of teeth so that rotation of the first rotatable member will cause the second and third rotatable members to rotate at different rotational speeds. This, in turn, causes relative rotational movement to occur between the second and third rotatable members. A movable stop member is provided in movable relation with the second rotatable member and this movable stop member is disposed in sliding contact with an annular groove of the third rotatable member. The annular groove is provided with ramps which cause the movable stop member to move away from the third rotatable member during a portion of its rotation after the second rotatable member has rotated a predetermined number of revolutions.

Abstract: An improved no-back mechanism for propeller pitch control comprises a brake which resists motion of a first member and a uni-directional coupling between the first member and a drive connecting a pitch control prime mover to an adjustable pitch propeller. The coupling permits limited movement of the drive with respect to the first member during back driving as in dither cycling of the blade while coupling the drive and first member for braking the back driving after the limited movement. As a result, dither cycling can occur during normal operation without release or slipping of the brake, thereby effecting a substantial wear reduction of brake plates of the brake.

Abstract: A pitch controller (10) for controlling the pitch of a plurality of blades (11) of a fan powered by a turbine propulsion engine, with a pitch adjusting device (16) having an input (18) for controlling the pitch of the blades. An input drive shaft (15) provides rotary power from the free turbine to the first input of a transmission (14). The transmission also has a second input (25) controlling the input to the pitch adjusting device, a first output (18) which is the input to the pitch adjusting device and a second output (21) which is applied to a rotary power device (20). Input power from the free turbine is provided to the rotary power device by the transmission which in response to a pitch control signal (28) causes the second input to rotate at a speed different from the first input thereby changing the pitch of the blades in proportion to the pitch control signal.