| 摘要 |
<p>In a drum brake assembly a hydraulic actuator (16) is engageable with a pair of brake shoes (12, 14) to move the same into engagement with a rotatable member. A parking lever (26) also cooperates with the pair of brake shoes (12,14) to move the same into engagement with the 'rotatable member and an anchor plate (34) forms a connecting member between the pair of brake shoes. A backing plate (10) supports the pair of brake shoes (12,14) and the anchor plate (34). The anchor plate (34) is movably supported by the backing plate (10) and a latch (36) cooperates with the anchor plate (10) in a first position to fix the anchor plate (34) to the backing plate (10). The latch (36) is movable to a second position spaced from the anchor plate (10) to permit the latter to move relative to the backing plate (10). In order to control the position setting of the latch (30), the latch is coupled to the parking lever (26) so that the latch (36) remains in the first position until the parking lever (26) is moved whereupon the latch (36) is also moved to the second position. Consequently, when the hydraulic actuator (16) is operated in a service brake application, the anchor plate (34) remains fixed to the backing plate (10) to form a non-servo drum brake and when the parking brake (26) is operated, the anchor plate (34) is movable with the pair of brake shoes (12,14) in the direction of the rotatable member (18) to form a duo-servo drum brake.</p> |
