Patent ID: 7270220
Filing Date: 2007-09-18
Classification: F16D

Abstract:
1. In a brake having a first web with friction lining attached thereto and a second web with friction lining attached thereto that engage a friction surface on a drum to effect a brake application while at the same time creating thermal energy, an extendable strut having a first member connected to the first web that is separated from a second member connected to the second web by an adjuster mechanism for maintaining a running clearance between the friction linings and the friction surface, said adjuster mechanism having a star wheel with a first shaft located in a first bore in the first member and a second shaft with threads thereon that are mated with a threaded bore of a second member and a pawl with a first leg connected by a spring to said second web and a second leg connected to the star wheel such that with movement of said first and second webs during the brake application, the pawl pivots and when the running clearance exceeds a predetermined distance rotates the star wheel to correspondingly move the threaded shaft out of the threaded bore and incrementally extend the extendable shaft such that a maximum running clearance is maintained, a bimetallic member for disconnecting the second leg of the pawl from the star wheel when the thermal energy generated during a brake application exceeds a predetermined temperature and thereby prevent the pivoting of the pawl from rotating the star wheel as a result of thermal expansion of the drum; said brake being characterized by said pawl being located on a pin that is fixed to the first web; and by said bimetallic member being defined by a v-shaped clip having a first leg that is held against the first web by said pin and a second leg that engages said first leg of the pawl, said first web receiving thermal energy during a brake application that is directly conducted into said first leg of the clip such that the second leg immediately responds by expanding and after overcoming a component force of said spring acts on the first leg to move the second leg of the pawl away from the star wheel when the predetermined temperature develops during a brake application to assure a minimum running clearance is present after a brake application.