INTERNAL SHOE DRUM BRAKES

摘要

An internal shoe drum brake having a pair of brake shoes mounted on a back plate with double ended expanders located one between each pair of adjacent ends of the shoes. The expander has a strut assembly slidable within itself so that when the expander is operated the strut assembly transmits braking loads from one shoe to the other so that the brake operates in a duo servo mode. With the expanders arranged to operate vertically the weight of the shoes and acts against the strut assembly. In order to support the upper brake shoe and prevent the shoes moving off-center a variable length support acts between the upper shoe and the wheel cylinder. The support has a spring therein so that the support can resiliently collapse when the sheos move during duo servo braking.