Parking brake assembly with wear adjustment for heavy road vehicle disc brake

摘要

In a disc brake ( 10 ) having a disc ( 16 ) and a brake shoe ( 82 ) movable towards and away from a friction surface ( 86 ) provided on one face of the disc ( 16 ), there is provided a parking brake ( 22 a /22 b) having a pushing member ( 44 a /44 b) for moving the brake shoe ( 82 ) towards and away from the friction surface ( 86 ) of the disc ( 16 ). The parking brake ( 22 a /22 b) further includes a cam ( 36 a /36 b) displaceable between a first position in which the cam ( 36 a /36 b) forces the pushing member ( 44 a /44 b) against a biasing force acting thereon to maintain the brake shoe ( 82 ) in friction engagement with the disc ( 16 ) and a second position in which the pushing member ( 44 a /44 b) is free to move in a direction away from the disc ( 16 ) to release the brake shoe ( 82 ) from the friction surface ( 86 ) of the disc ( 16 ). A piston and cylinder arrangement ( 28 ) is provided to displace the cam ( 36 a /36 b) between its first and second positions.