Patent ID: 8205540

Claim:
A piston-cylinder unit comprising: a cylinder having a closed first end; a piston installed in the cylinder configured to move along a longitudinal axis of the cylinder, the piston dividing the cylinder into a first chamber remote from the closed first end and a second chamber proximate to the closed first end; a piston rod, which is attached to one side of the piston, the piston rod projects through the first chamber along the longitudinal axis of the cylinder, and passes out of a second end of the cylinder through a guide at the second end of the cylinder, the second end of the cylinder being opposite the closed first end; a first locking element provided on the piston rod, and a second locking element provided on the cylinder, wherein the first and second locking elements are adapted to establish a mechanical interlock, and the first locking element comprises at least one latching arm that cooperates with the second locking element by engaging with it to produce the mechanical interlock; wherein the first locking element further comprises a stepped ring disk having an opening through which the at least one latching arm extends; and a spring between the stepped ring disk and a side of the piston facing a first connecting device, wherein the spring exerts a force on the stepped ring disk in the direction toward the first connecting device, thus pushing the stepped ring disk against a portion of the at least one latching arm pretensioning the at least one latching arm toward the longitudinal axis of the cylinder.