Abstract: A fluid pressure actuator which locks in the extended position. The lock is a roller operated, dual segment pawl mechanism that unlocks in response to a pressure difference between extend and retract pressures. The two lock segments, chamfered for engagement with the cylinder end, are in diametrically opposed slots in the actuator piston head. A cylindrical section projects from the segment portion. An end view of the lock is mushroom shaped. Two rollers, held in alignment normal to the actuator centerline by a cage integral with an unlock rod, operate in conjunction with the lock cam surfaces in such a manner as to carry the radial loading imposed when in the lock mode.The rolling action of the rollers, combined with the radial application of locking force provides low friction operation of the lock.

Abstract: A fluid pressure actuator which locks in the extended position. The lock is a roller operated, dual segment pawl mechanism that unlocks in response to a pressure difference between extend and retract pressures. The two lock segments, chamfered for engagement with the cylinder end, are in diametrically opposed slots in the actuator piston head. A cylindrical section projects from the segment portion. An end view of the lock is mushroom shaped. Two rollers, held in alignment normal to the actuator centerline by a cage integral with the unlock rod, operate in conjunction with the lock cam surfaces in such a manner as to carry the radial loading imposed when in the lock mode.In operation, when the actuator is driven to its extreme extend position, the pawls are driven out by the rollers and lock against the cylinder end. The linear force on the rollers is due to the preload spring plus the hydraulic pressure differential (extend pressure greater than retract pressure).