Patent ID: 6386508
Filing Date: 2002-05-14
Classification: B29C,F15B

Abstract:
A pressurized-fluid-operated actuator comprising:a) a tubular outer cylinder defining an inner cylindrical surface, the outer cylinder having a longitudinal axis; b) a piston slidably carried within the outer cylinder for axial movement therewithin and having a rod affixed thereto, the rod extending from an end of the piston in an axial direction relative to the outer cylinder, wherein the piston divides the outer cylinder into a head end chamber and a rod end chamber that is axially spaced from the head end chamber, and wherein the piston includes an inner cylinder; c) a dividing wall extending transversely within the inner cylinder and at a fixed axial position relative to the outer cylinder to divide the inner cylinder into a first inner chamber and a second inner chamber; d) a first fluid conduit in fluid communication with the head end chamber and with the first inner chamber for moving the piston and rod in a first axial direction relative to the outer cylinder, to cause the rod to move in a outward direction relative to the outer cylinder to provide a rod extension stroke when pressurized fluid is introduced into the first fluid conduit; and e) a second fluid conduit in fluid communication with the second inner chamber for moving the piston and rod in a second axial direction relative to the outer cylinder and opposite from the first axial direction, to cause the rod to move in an inward direction relative to the outer cylinder to provide a rod retraction stroke when pressurized fluid is introduced into the second fluid conduit.