Abstract: In a servo-valve arrangement, a control piston is displaced as a function of steering forces to be applied which control piston in its turn controls throttling places in such a manner that a piston-cylinder aggregate is acted upon with a pressure difference and produces a force assisting the steering movement. A throttling section connected in parallel with the piston cylinder aggregate includes throttling places controlled by external parameters as well as by the system pressure and makes it possible to act upon the end faces of the control piston with a pressure difference in order to permit a force opposing the respective displacement of the control piston to act on the control piston. As a result thereof, an undesired overcontrol of the servo-valve arrangement, respectively, of the steering system controlled thereby is avoided.

Abstract: A vacuum type booster which includes a booster piston reciprocatively movable in a shell, a valve sleeve for a control valve fitted to the booster piston and having a disengagement preventive flange superposed on the piston, and a clamp plate engaged with pawls formed by cutting and bending portions of the booster piston for clamping the flange to the booster piston. The booster piston includes pairs of reinforcement ribs which cross the turning direction of the clamp plate and sandwich cutout holes resulting from formation of the pawls. A pair of the ribs on the rear side of the turning direction of the clamp plate permit the clamp plate to turn in a direction for engagement with the pawls and inhibits the clamp plate from turning in the disengaging direction. A space is provided between the outer peripheral part of the disengagement preventive flange and an engagement piece jointing part of the clamp plate body.

Abstract: A fluid-pressure operated actuator comprises a housing, at least one piston reciprocable in the housing, a rotatable output shaft having a portion thereof within the housing, means operatively connecting the piston and the output shaft, and stop means mounted on the housing and engageable with the shaft portion for limiting rotary movement of the shaft.