SPRING-APPLIED, HYDRAULICALLY RELEASED BRAKE ACTUATOR HAVINGPOSITIVE CLEARANCE SLACK ADJUSTER MECHANISM

摘要

A spring-applied, hydraulic pressure released brake actuator having a modular slack adjuster assembly in which a friction ring is arranged to limit axial movement of a nut member to which a brake shoe is connected, thereby establishing a predetermined brake shoe clearance with a vehicle wheel or brake disc. A spindle that is threadedly engaged with the nut member is connected to the actuator piston by means of a cone clutch that is disengaged during a brake release in the event the return stroke of the piston exceeds the predetermined brake shoe clearance due to brake shoe wear during the preceding brake application. This disengagement of the clutch causes the spindle to be rotated relative to the nut member under the influence of a slack adjuster spring in order to compensate the piston overtravel.