| 摘要 |
An actuator for a drum brake including a plunger connected through a resilient member to a linkage attached to a web on a brake shoe. A rod extends from the plunger and engages a lever arm that is pivotally retained on the web. The lever engages an extendable strut of an adjuster arrangement through which a running clearance is maintained between the brake shoe and a drum. During a brake application, pressurization fluid acts on the plunger to develop an operational force that is communicated through the resilient member to move the brake shoe into engagement with a drum. Should the operational force overcome the resilient member, the plunger moves toward the linkage and a reactive force is applied through the rod that acts through the lever arm to prevent a pawl from rotating such that a current length of the strut and correspondingly a current running clearance is sustained.
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