PULL-TYPE PISTON AND CYLINDER ACTUATOR

摘要

PCT No. PCT/US86/02762 Sec. 371 Date Jul. 31, 1987 Sec. 102(e) Date Jul. 31, 1987 PCT Filed Dec. 18, 1986 PCT Pub. No. WO87/03850 PCT Pub. Date Jul. 2, 1987.A hydraulic master cylinder formed by telescopically fastening together a pair of cylinder housings to form a cylinder. A piston in the cylinder is operative to transfer hydraulic fluid to a slave cylinder connected to the master cylinder. The pressure or power stroke of the piston is effected by exerting a pull on the piston by a pull cable attached to one side of the piston. A body, attached to one of the cylinder housing, provides a reservoir for hydraulic fluids. A cap on the reservoir closes a fluid filling opening. Expansion bellows in the reservoir accommodates changes in the fluid level in the reservoir as the piston is being reciprocated. The bellows is connected to the cap so as to be removed as a unit with the cap when the reservoir is being filled. In one embodiment of the invention the pair of cylinder housings are secured together by threaded connector means and a single O-ring is used as a seal from the ambient pressure as well as a seal between high and low pressure sides of the pressure chamber. In another embodiment of the invention, the housings are formed of a plastic material and are snappingly secured to each other by insertion of one member within the other member. This embodiment also includes locator means to ensure that the housing members will be properly angularly located relative to each other in their assembled position.