DISC BRAKE SHOE RETRACTION MECHANISM

摘要

A retraction mechanism (30) for a disc brake assembly (10) which applies a generally constant restoring force urging brake shoes (15, 16) apart from one another regardless of the amount of wear of the friction pads. The disc brake assembly (10) includes an anchor plate (11) upon which a caliper (20) is slidably mounted. A mechanism (30) is provided for selectively moving the brake shoes (15, 16) into frictional engagement with a rotor (17) to retard or stop rotation thereof. The retraction mechanism (30) includes a pair of retractor clips (30) which are mounted on the anchor plate (11) for spreading the brake shoes (15, 16) apart from one another when the disc brake assembly (10) is subsequently released. The retractor clips (30) are serpentine-like in shape, having straight portions (33a) which are connected together by intermediate curved portions (33b). The outer ends of the retractor clips (30) terminate upwardly extending posts portions (33c) and outwardly extending finger portions (33d) which engage the brake shoes (15, 16). The forces exerted by the retractor clips (30) on the brake shoes (15, 16) are substantially uniform, regardless of the amount of wear on friction pads of the brake shoes. Thus, such forces cannot overcome the urging of a roll-back seal (27) and undesirably move the piston (25) away from the rotor (17) by a distance which is greater than a desired predetermined distance.