Patent ID: 6016892
Filing Date: 2000-01-25
Classification: F16D

Abstract:
A hydraulic brake actuator of the type having a piston translatable within a cylindrical bore in a housing between a quiescent retracted position with a preferred clearance space between one piston end and a brake member, and an extended position with said piston end engaging and actuating the brake member in response to the application of hydraulic fluid pressure; the actuator comprisinga return spring operable upon relief of the hydraulic fluid pressure to urge the piston back from the brake member engaging position to the retracted position, and an internally disposed mechanical piston clearance space adjuster comprising:normally fixed anchor means for engaging and holding one end of the return spring during spring deformation;means for moving the anchor means to a new fixed location in response to piston translation exceeding the preferred clearance space thereby changing the quiescent position to which the return spring forces the piston and reestablishing the preferred clearance space;the anchor means comprising inner and outer concentric sleeves, the inner sleeve having a first rim biased by said one end of the return spring and a second rim for engaging one end of the outer sleeve, the piston located coaxially within the inner sleeve, the return spring located coaxially with the piston and intermediate the piston and inner sleeve, the piston, return spring, and inner and outer sleeves all located coaxially within the cylindrical bore, and the outer sleeve compressable by the adjuster during movement of the outer sleeve toward the new fixed location.