Self-contained gas cylinder

Claim 1

A gas cylinder element comprising: a cylinder having an annular bore (11); a piston rod capable of a sliding movement axially within and relative to the cylinder; a guide bushing (20, 20') seated at one end face of the cylinder for sealingly engaging said piston rod and through which said piston rod extends into said cylinder; said guide bushing, cylinder, and piston rod defining an enclosed working space for containing gas under pressure, against which pressure the piston rod can be urged to provide a spring effect; wherein said guide bushing (20, 20') is provided with an annular recess (21) facing the piston rod for receiving lubricant, said guide bushing further having an annular passage through which the piston rod passes with small radial tolerance between the piston rod and guide bushing, the guide bushing (20, 20') further being provided with an essentially radially extending lubricant channel (22), which at one end is in communication with the recess (21) and at the other end is in communication with a closeable lubricant supply inlet borehole (12) extending essentially radially through the cylinder (10).