Variable adjuster for disc brake

In a disc brake, a rotor having a pair of friction faces, a pair of friction elements, one of said elements being disposed adjacent each of said friction faces, a fixed support, a caliper housing slidably mounted on said fixed support for urging the friction elements into braking engagement with their corresponding friction faces, and actuating means for causing said caliper housing to urge said friction elements into braking engagement with said friction faces, said actuating means including automatic adjustment means for limiting retraction of said piston to a predetermined running clearance, said adjustment means including an extensible member comprising a pair of relatively rotatable components, and a ratchet mechanism for rotating one of said components relative to the other component, said ratchet mechanism including a pivoting pawl and a toothed member for engagement by the pawl, said pawl including a pair of keys axially facing the toothed member and engageable therewith to rotate said one component a predetermined increment when one of said pair of keys engages the toothed member and a second predetermined increment when the other of said pair of keys engages the toothed member, caused by movement of said toothed member axially away from said pawl and said pair of keys being rotationally disposed to each other relative to the pivot of said pawl so that said pair of keys are engageable with the toothed member separately.