COMBINING THE FEATURES OF DISC AND SHOE BRAKES 570021
THE disc-servo brake was designed to eliminate brake fade. To overcome limitations of existing brake structures, desirable features of the disc and shoe brakes were combined.
The introduction of three friction surfaces, two pads, and a shoe, and the addition of a ball-and-ramp self-energizing mechanism contribute, the author says, to a brake that has greater fade resistance and longer wear of small segments of the brake lining.