Fluid-operated cylinder with piston in two parts

摘要

A piston (5) of a fluid-operated cylinder (1), with housing (2) and piston rod (8) projecting from the housing, has two parts (6, 7), positioned axially one behind the other and sealed from the piston rod. At least one of the parts is axially movable on the piston rod, such that the piston seal (10) and at least one of the piston parts have sloping surfaces (12-15) abutting one another to form a self-locking arrangement for the seal on the running surface (4) of the cylinder when pressure is not acting. Preferably a spring arrangement (17) is provided on the piston rod, acting on the seal via the inclined surface to cause radial expansion. The piston seal is preferably of polyacetal resin or polyamide.