Actuator

An actuator, comprising:

• a hydraulic force translator with a first piston unit and a second piston unit that move relative to each other, wherein:
• the first piston unit has an effective area that is larger than the second piston unit,
• the first piston unit and the second piston unit enclose a pressure chamber together with a spacer, and
• the spacer can be fixed relative to a stationary chassis by a hydraulically operated clamping device that applies an axial force;
• a first pressure reservoir and a second pressure reservoir adapted to be connected via a valve arrangement to a chamber of the force translator, the first pressure reservoir having a higher pressure than the second pressure reservoir, wherein the chamber of the force translator is:
• operatively connected to the second piston unit,
• enlarged during an out-movement of the second piston unit,
• connected to the second pressure reservoir via the valve arrangement, and,
• connected via the valve arrangement to the first pressure reservoir so as to charge the first pressure reservoir when reducing the chamber in size;
• and
• a directional control valve that connects the first pressure reservoir to the clamping device.