초록 ▼

In a drum brake assembly a hydraulic actuator is engageable with a pair of brake shoes to move the same into engagement with a rotatable member. A parking lever also cooperates with the pair of brake shoes to move the same into engagement with the rotatable member and an anchor plate forms a connect

In a drum brake assembly a hydraulic actuator is engageable with a pair of brake shoes to move the same into engagement with a rotatable member. A parking lever also cooperates with the pair of brake shoes to move the same into engagement with the rotatable member and an anchor plate forms a connecting member between the pair of brake shoes. A backing plate supports the pair of brake shoes and the anchor plate. The anchor plate is movably supported by the backing plate and a latch cooperates with the anchor plate in a first position to fix the anchor plate to the backing plate. The latch is movable to a second position spaced from the anchor plate to permit the latter to move relative to the backing plate. In order to control the position setting of the latch, the latch is coupled to the parking lever so that the latch remains in the first position until the parking lever is moved whereupon the latch is also moved to the second position. Consequently, when the hydraulic actuator is operated in a service brake application, the anchor plate remains fixed to the backing plate to form a nonservo drum brake and when the parking brake is operated, the anchor plate is movable with the pair of brake shoes in the direction of the rotatable member to form a duo-servo drum brake.

대표청구항 ▼

In a drum brake assembly having a pair of brake shoes which are engageable with a rotatable member during a brake application, said brake shoes having pairs of confronting ends, an expansible actuator received between one pair of said confronting brake shoe ends to move said brake shoes into engagem

In a drum brake assembly having a pair of brake shoes which are engageable with a rotatable member during a brake application, said brake shoes having pairs of confronting ends, an expansible actuator received between one pair of said confronting brake shoe ends to move said brake shoes into engagement with said rotatable member, a backing plate supporting the pair of brake shoes, a parking lever cooperating with the pair of brake shoes to move the latter into engagement with the rotatable member to effect a parking brake application responsive to movement of said parking lever to a brake applied position, characterized by means cooperating in a first position with the other pair of confronting brake shoe ends to pivotally anchor the pair of brake shoes to the backing plate, said means spacing apart said other pair of confronting brake shoes ends, said means further being responsive to movement of the parking lever to the brake-applied position to move to a second position to release the pivotal anchor between the pair of brake shoes and the backing plate, said means including a plate extending between and engageable with the other pair of confronting brake shoe ends to define a substantially invariant spacing between said other pair of confronting brake shoe ends, said plate being movably carried by said backing plate, and said means also including a latch cooperating with said plate to lock said plate to the backing plate when said means is in the first position, thereby preventing movement of said plate.