Patent ID: 7100746

Claim:
A drum brake ( 1 ) for a vehicle wheel having a backing plate ( 2 ), a drum ( 3 ), a first brake shoe ( 4 ), a second brake shoe ( 5 ), a hand-brake lever ( 6 ), a slack-takeup lever ( 21 ), a link ( 29 ) and spring means ( 30 ) wherein said first brake shoe ( 4 ) is connected to said second brake shoe ( 5 ) through said link ( 29 ), said hand-brake lever ( 6 ) is retained on a first hinge ( 23 ) on said first brake shoe ( 4 ) and said slack-takeup lever ( 21 ) is hinged ( 24 ) on said second brake shoe ( 5 ) and said slack-takeup lever ( 21 ) is connected to said hand-brake lever ( 6 ) through said link ( 29 ), and said spring means ( 30 ) acts to urge said first brake shoe ( 4 ) toward said second brake shoe ( 5 ), characterized in that said hand-brake lever ( 6 ) has an abutment ( 34 ) that engages the first brake shoe ( 4 ) to limit me movement of said first brake shoe ( 4 ) and said second brake shoe ( 5 ) toward each other by the spring means ( 30 ) to define a first diameter ( 20 ) for the first brake shoe ( 4 ) and second brake shoe ( 5 ) as established by the length of said link ( 29 ) to creates a desired operating clearance ( 37 ) between linings ( 19 ) associated with the first brake shoe ( 4 ) and second brake shoe ( 5 ) and a wall ( 12 ) on said drum ( 3 ) with the abutment ( 34 ) on the hand-brake lever ( 6 ) engaging the first brake shoe ( 4 ); and wherein said backing plate ( 2 ) has an opening ( 32 ) that is in axially alignment with the hand-brake lever ( 6 ) when the abutment ( 34 ) engages the first brake shoe ( 4 ); and wherein said hand-brake lever ( 6 ) responds to an axial input applied through said opening ( 32 ) by deflecting such that the abutment ( 34 ) is axially moved out of engagement with said first brake shoe ( 4 ) and the hand-brake lever ( 6 ) thereafter pivots on the first hinge ( 23 ) to allow said hand-brake lever ( 6 ) to move toward an inner rim ( 18 ) on the first brake shoe ( 4 ) such that the first brake shoe ( 4 ) is moveable toward said second brake shoe ( 5 ) to define a smaller second diameter for the first brake shoe ( 4 ) and the second brake shoe ( 5 ) and establish an assembly clearance ( 36 ) between the linings ( 19 ) and wall ( 12 ) of the drum ( 3 ).