Abstract: A servo-steering mechanism for vehicles with a feedback of a load-dependent reaction moment onto the steering hand wheel by means of at least one reaction pressure cylinder connected with a working pressure chamber, in which a reaction pressure piston operating onto the steering hand wheel is adapted to be actuated in one direction of its piston axis by the working pressure and in the other direction of its piston axis is adapted to be supported at a support spring and is also adapted to come into abutment at a stop fixed relative to the reaction pressure cylinder, when the working pressure has been brought to a value corresponding to the prestress of the support spring; between its starting position with an unstressed support spring and its shut-off or turn-off position at the associated stop the reaction pressure piston thereby comes into additional abutment at least at one reducing spring counteracting the working pressure, whereby the reducing spring is adapted to be supported either directly or by way of

Abstract: A by-pass valve for servo-steering systems to turn off the working pressure in a cylinder chamber of a pressure medium cylinder, whose valve housing includes a valve connection adapted to be connected with the cylinder chamber, a valve connection adapted to be essentially pressure-relieved, and a valve seat for a check valve operatively connected between the two valve connections; the valve housing is thereby adjustable relative to the axis of a steering shaft for purposes of changing the position of its valve seat while the closure member of the check valve is thereby retained by springy means in its normal position closing-off the valve connections with respect to one another and is actuatable into its by-pass position connecting the valve connections with each other by way of a stem movable in unison with the closure member by way of a cam surface fixed for movement in unison with the steering shaft; the valve housing is thereby exclusively rotatable in relation to its valve housing axis but is immovably s

Abstract: A pressure medium servo-motor, especially for servo-steering systems, in which a working piston operating in a working cylinder is provided with a piston pressure surface actuatable by the pressure in one working pressure chamber of the working cylinder for producing a servo-force directed in the sense of the relative movement of the working piston with respect to the working cylinder; the piston pressure surface of the working piston is thereby reduced with respect to the reference value fulfilling the equilibrium condition of the piston pressure forces in the neutral position of the working piston, by a reducing piston which includes a pressure disengaging surface actuatable by the pressure in the working pressure chamber and a relief pressure surface actuatable by the pressure in a relief pressure chamber.

Abstract: A control valve for a pressure medium servo-motor of a servo-steering mechanism whose valve-adjusting member includes a reaction pressure surface that is immovable relative thereto and is adapted to be acted upon by the reaction pressure in a reaction pressure chamber connected exclusively to one of the two working pressure chambers of the working cylinder of the servo-motor; the valve-adjusting member is also connected with the reaction piston in such a manner as to enable a limited free relative adjusting path between the valve-adjusting member and the reaction piston; the reaction piston, in its turn, includes a reaction relief pressure surface which is adapted to be acted upon by the reaction pressure in a reaction pressure chamber connected exclusively to the same working pressure chamber and which is oppositely directed to the reaction pressure surface; the reaction piston is also supported with respect to the valve housing by means of a spring member which is under a prestress force while its reaction