Piston assembly for dual-network disk-brake system

Claim 1

A vehicle-brake system comprising: dual-compartment master cylinder means including respective compartments and plungers for independently displacing two brake fluid streams; a pair of transmission networks each connected to one of said compartments for transmission of the brake fluid displaced from said compartments; and a disk brake including: a rotatable brake disk, a nonrotatable housing reaching around the periphery of the disk and forming on one side thereof an actuating cylinder, a pair of brakeshoes flanking said disk and including a first brakeshoe remote from said cylinder and in force-transmitting relationship therewith and a second brakeshoe proximal to said cylinder, and piston means in said cylinder acting upon said second brakeshoe proximal thereto while subdividing said cylinder into a pair of independent working chambers respectively communicating with said networks and individually pressurizable thereby for displacing said brakeshoe against said disk, said piston means including a first piston forming one of said chambers and a second piston coaxial with the first piston and defining another of said chambers effective upon pressurization to shift said brakeshoes, and means for transmitting force to the respective brakeshoes between said pistons upon failure of the fluid supply to one of said chambers, said first and second pistons being formed as axially open hollow pistons and said means for transmitting force being formed as a disk-shaped piston between said first and second pistons and a pair of self-adjusting mechanisms received respectively in said first and second pistons and mounted upon said disk piston, said self-adjusting mechanism each comprising a threaded sleeve-and-spindle assembly effecting force transmission between said pistons upon failure of fluid supply to either of said chambers.