Fluid pressure cylinder with a lock mechanism

A fluid pressure cylinder with a lock mechanism, comprising a piston sliding in a cylinder tube in response to operation of air pressure, pressure chambers on both sides of the piston, two cylinder ports separately communicating with the respective pressure chambers, a piston rod extending from the piston through a lock mechanism cover on one end of the cylinder tube, and a lock mechanism provided in the lock mechanism cover;

• wherein the lock mechanism includes brake shoes surrounding an outer periphery of the piston rod, a shoe holder for holding the brake shoes, a retainer fitted at an outside of the shoe holder, a plurality of balls held in pockets of the retainer and in contact with an outer face of the shoe holder, a tapered ring fitted at an outside of the retainer and having on an inner side the rest a tapered face in contact with the balls, a brake spring elastically urging the tapered ring toward a locked position where the balls are pressed against the shoe holder by the tapered face, a release piston connected for causing the tapered ring to return to an unlocked position against the brake spring, a pressure chamber formed on one side of the release piston, an unlocking port for feeding compressed air to the pressure chamber, and a manual actuator connected for causing the release piston to return to the unlocked position by manual operation;
• and
• wherein one of the two cylinder ports is provided to an end portion of the lock mechanism cover thereof on a side to which the cylinder tube is connected, the unlocking port and the manual actuator are provided to an end portion of the lock mechanism cover opposite to the side provided with the cylinder port of the lock mechanism cover, and a flat area is provided around the unlocking port so that the valves can be installed to control compressed air fed through the unlocking port.