Hydraulic actuator

A hydraulic actuator comprising a body, in which a control arm and a lift means provided with a first piston surface are arranged, which lift means is arranged to follow the reference movement of the control arm, and an inlet port and an outlet port for hydraulic medium, which body encloses a pressure chamber delimited by the first piston surface of the lift means and a chamber delimited by a second piston surface of the lift means, said second piston surface being smaller in area than said first piston surface, wherein the movement of the control arm provides a flow connection between the inlet port and the pressure chamber in order to move the lift means and the movement of the control arm provides a flow connection between the chamber and outlet port, and wherein the pressure of the hydraulic medium in the chamber is arranged to urge the lift means in the opposite direction, wherein the movement of the control arm in the opposite direction provides a flow connection between the pressure chamber and the outlet port in order to move the lift means (6) in the opposite direction, and the movement of the control arm in the opposite direction provides a flow connection between the inlet port and the chamber.