Rotary shaft hydraulic for producing zero net torque - uses two parallel racks separated by pinion and moves both racks simultaneously in opposite senses by hydraulic forces on their ends

摘要

The actuator for aircraft or nautical usage holds the set position of the actuated shaft, despite hiqh inertia forces during manoeuvres, by a double activation in which inertia forces produce zero net couple in the shaft. Two toothed racks terminated by sealed pistons at both ends, lie parallel to each other separated by a central toothed pinion which meshes with both racks. The pinion shaft is mechanically coupled to the actuated device. To position the actuating shaft, hydraulic fluid is admitted to opposite ends of opposite racks forcing one rack to the right and the other to the left, rotating the pinion as they move. Inertia forces having a component along the line of the racks result in a zero net couple on the piston, so the position of the actuating shaft is unaltered.