Patent ID: 7237471

Claim:
A continuously lockable adjustment device for immobilizing elements which are movable relative to each other, said device comprising: a stepped cylinder having a first cylinder step and a second cylinder step, the second cylinder step having a larger cross-sectional area than the first cylinder step; a stepped piston comprising a first chamber and a second chamber, the piston having a first piston step guided in the first cylinder step and a second piston step guided in the second cylinder step; and a piston rod connected to the piston opposite the first piston step and extending sealed off out an end of the cylinder; wherein the cylinder has a first working space and a second working space separated by the piston and filled with a working fluid in which the piston can be displaced axially, thereby displacing working fluid from one working space to the other working space; wherein the piston is a hollow piston through which the working fluid can flow; and wherein the first chamber has an inlet orifice connected to the first working space and closable by a first valve and the second chamber has an inlet orifice connected to the second working space and closable by a second valve.