Patent ID: 7624671
Filing Date: 2009-12-01
Classification: F15B,F16H

Abstract:
1. A hydraulic actuator for a hydraulic servomotor having a first chamber and a second chamber, the actuator being connected to a fluid source and a fluid drain, the actuator comprising: a first valve fluidly connected between the fluid source and the first chamber, said first valve being of a kind which is closed in an energized state and allows a fluid flow between the fluid source and the first chamber in a de-energized state at least in a direction from the fluid source towards the first chamber, a second valve fluidly connected between the first chamber and the fluid drain, said second valve being of a kind which, in a de-energized state, prevents a fluid flow between the first chamber and the fluid drain, a third valve fluidly connected between the fluid source and the second chamber, said third valve being of a kind which, in a de-energized state, prevents a fluid flow between the second chamber and the fluid source, at least in a direction from the second chamber towards the fluid source, and a flow channel arranged in fluid communication with the second chamber, said flow channel being arranged in such a manner that a fluid flow is allowed in a direction out of the second chamber via the flow channel.