Abstract: An apparatus for restricting the velocity of movement of the piston of a servo-controlled operating hydraulic unit, when the piston approaches at least its one end position in the cylinder, by means of a hydraulic sensor fixedly mounted on one of the machine parts which is shifted with respect to each other by means of the operating hydraulic unit, and is coupled by the intermediary of a non-return valve to the servo-circuit. When the piston of the operating hydraulic unit approaches its end position in the cylinder, the hydraulic sensor is actuated by the second of the above-mentioned machine parts, whereby a pressure is established in the cylinder of the hydraulic sensor which exceeds the servo-pressure. A valve senses the pressure difference between the servo-pressure and the pressure established by means of the hydraulic sensor and throttles the servo-flow to the main valve of the operating hydraulic unit the main valve thereby throttling the pressure medium supply to the operating hydraulic unit.