Patent ID: 8157552

Claim:
A rotary fluid pressure device comprising: a housing member defining a fluid inlet and a fluid outlet; a valve member in fluid communication with the fluid inlet and the fluid outlet; a gerotor displacement mechanism in fluid communication with the valve member, the gerotor displacement mechanism including: a ring member defining an axis, wherein the ring member rotates about the axis; a rotor member eccentrically disposed in the ring member, the rotor member orbiting about the axis of the ring member, the rotor member defining a central opening; a drive shaft engaged to the rotor member, the drive shaft defining an axial bore that extends through the drive shaft; a brake pin slidably disposed in the axial bore of the drive shaft, the brake pin having a first axial end and a second axial end; a release piston disposed against the first axial end of the brake pin; and a lock piston acting against the second axial end of the brake pin, the lock piston being moveable between an engaged position and a disengaged position, the lock piston being disposed in the central opening of the rotor member in the engaged position to prevent the rotor member from orbiting, the release piston acting against the first axial end of the brake pin to move the lock piston to the disengaged position.