| 摘要 |
<p>DRUM BRAKE WITH AUTOMATIC ADJUSTMENT A drum brake includes a pair of brake shoes and a hydraulic actuator which is engageable with the brake shoes to expand the latter during braking. The hydraulic actuator carries a pair of elastomeric sealing rings which are deformable during braking as a pair of pistons slidably disposed with the hydraulic actuator are movable upon a braking application. When braking is terminated, the elastomeric sealing rings return to their original stored configuration thereby retracting the pair of pistons within the hydraulic actuator. In order to retract the pair of brake shoes with the pistons through a predetermined distance, a first spring engages the pair of brake shoes substantially opposite the hydraulic actuator and biases the brake shoes toward each other while a second spring biases the brake shoes away from each other. The second spring is carried by a strut on a parking brake actuator and the strut extends from one of the brake shoes to a lever which is pivotally mounted on the other brake shoe.</p> |
