Self adjusting electrically powered parking brake actuator mechanism with manual release

摘要

An electrically powered actuator mechanism for operating a vehicle parking brake including a reversible electrical motor having output gearing driving a sector gear. A wrapped spring clutch drivingly connects the sector gear to an intermediate operator cable wind up wheel. The intermediate cable is connected to the brake cable to set the brakes when the operator cable is wound up by energization of the motor in one direction, with a load sensor turning off the motor when a predetermined tension load is reached. Locking motor gearing holds the brake in the set condition. Reversal of the motor upwinds the cable to release the parking brake. A self adjusting feature is provided by a pretensioned clock spring creating a torsional bias on the wind up wheel tending to maintain a predetermined tension in the brake cable. A spring clutch is released by engagement of a release arm to allow the clock spring to adjust the wind up wheel. A cable operated manual release causes a release lever to engage the clutch spring release arm to allow the cable to release although the clock spring monitoring a minimum tension after release of the winding wheel.