Patent ID: 6918468
Filing Date: 2005-07-19
Classification: F16D

Abstract:
1. A brake adjuster for adjusting the working clearance of the shoes of an automotive drum brake, the adjuster including three co-axial elements: a first rod element having a head portion for engagement with a first brake shoe and a threaded stem portion; an intermediate element in threaded engagement with the first rod element; a second rod element having a head portion for engagement with a second brake shoe and a stem portion slideably connected with the intermediate element and free to rotate relative thereto; a reaction member mounted on the intermediate element; a ring gear for rotation with the intermediate element and axially located between the second rod element and the reaction member; a leaf spring acting between the second rod element and the reaction member for pushing the second rod element away from the intermediate element, said leaf spring carrying a pawl designed to engage the ring gear, and a temperature sensitive mechanism designed to prevent the ring gear rotating when the brake temperature exceeds a pre-set value; the adjuster being characterised in that the temperature sensitive mechanism is provided by forming the pawl as a bimetallic laminate having flaps thereon which are folded around the edge of the spring and which engage recesses in the edge of the spring so that during a normal operation the pawl engages the ring gear to operate the adjuster and at temperatures above a pre-set value the pawl is deflected out of engagement with the ring gear to prevent adjustment.