Patent ID: 7823709

Claim:
A piston-cylinder comprising a cylinder, a piston rod having a section projecting out of said cylinder, said section having an end arranged distal from said cylinder, said end being threadably received through a through-hole defined in a mounting bearing forming a threaded joint connecting the piston-cylinder unit to a support and such that said end projects out of a distal side of said bearing relative to said cylinder, and a bellows covering said section of said piston rod for protecting said section of said piston rod against at least one of dirt and damage, wherein an unimpeded flow connection is provided in the end of said piston rod, said flow connection comprising a transverse bore leading to the interior space of said bellows and a longitudinal bore proceeding from said transverse bore and opening outside of said bearing on said distal side of said bearing, said flow connection being permanently open and communicating freely only with an interior space defined in said bellows and with the atmosphere such that said flow connection allows a free flow of air between the atmosphere and said interior space when said interior space in said bellows undergoes a change in volume in response to a relative movement between the bearing and the cylinder, wherein the cylinder comprises a lower attachment part formed with a circumferential groove, said bellows having a bead which engages said groove, and wherein the bellows comprises a collar surrounding said bead and which extends radially from said bead, said collar having a radially outer edge portion that is loaded axially against the cylinder.