Patent ID: 8545178

Claim:
A propulsor system comprising: a coarse pitch pressure circuit which supplies a coarse pitch pressure; a fine pitch pressure circuit which supplies a fine pitch pressure; a pitchlock pressure circuit which supplies a pitchlock pressure; a yoke assembly mounted along an axis of rotation, said yoke assembly including a pitch change actuator piston which separates a coarse pitch actuator chamber and a fine pitch actuator chamber, said coarse pitch actuator chamber pressurized by the coarse pitch pressure and said fine pitch actuator chamber pressurized by the fine pitch pressure; a pitchlock piston which separates a pitchlock piston pitchlock pressure chamber and a pitchlock piston coarse pitch pressure, said pitchlock piston pressure chamber pressurized by the pitchlock pressure and said pitchlock piston coarse pitch chamber pressurized by the course pitch pressure circuit; a pitchlock ballscrew screw mounted along an axis of rotation, said pitchlock ballscrew screw having an external screw ball track groove, said pitchlock ballscrew screw axially movable along said axis of rotation in response to axial movement of said pitchlock piston; a pitchlock nut mounted about said ballscrew screw, said pitchlock nut having an internal pitchlock nut thread; a ballscrew ballnut mounted about said pitchlock ballscrew screw and axially adjacent said pitchlock nut, said ballscrew ballnut includes an internal ballnut track groove; a ballscrew ballnut spring which biases said ballscrew ballnut toward said pitchlock nut, said ballscrew ballnut spring collapsible such that said pitchlock ballscrew screw is movable between an operational position and a pitchlock position, said internal pitchlock nut thread lockable with said external screw ball track groove in said pitchlock position; and a pitchlock solenoid valve in communication with the pitchlock pressure circuit, said pitchlock solenoid valve selectively operable to dump the pitchlock pressure such that said pitchlock ballscrew screw moves toward said pitchlock position.