Automatic parking brake for road vehicle may be placed in parking and test configurations and has auxiliary piston engaging threaded spindle and spring-loaded toward main piston

摘要

The automatic parking brake applies a disk brake. A brake caliper housing (1) has a main piston (5) with a sealing O-ring (8) moving in an open-ended cylinder and pressing the brake pad (11) onto the disk. A projection on the main piston extends into a small diameter open-ended cylinder in the auxiliary piston (4) with a small sealing O-ring (9). A set of springs (6) push the auxiliary piston toward the main piston. The auxiliary piston is sealed in a chamber by an O-ring (7). A female thread in the auxiliary piston engages a male thread (3) on a spindle (2) with an enlarged end forming a stop. The brake system may be placed in parking and test configurations.