Brake slip-controlled hydraulic brake system, especially for use with automotive vehicles

Claim 1

An anti-locking hydraulic brake system for an automotive vehicle, comprising: a master cylinder; at least one wheel brake, a master cylinder pressure conduit communicating said wheel brake with said master cylinder; a pressure fluid collector; a return conduit in communication with said wheel brake and said pressure fluid collector; an electromagnetically actuated outlet valve in said return conduit, said outlet valve in a resting position blocking said return conduit, and, in an actuated switching position, opening said return conduit; a hydraulically controlled inlet valve in said master pressure conduit; an auxiliary pressure pump having an intake taking in pressure fluid from said pressure fluid collector and having an outlet; an auxiliary pressure conduit feeding pressure fluid from said auxiliary pressure pump outlet directly to said wheel brake whenever said auxiliary pressure pump is operated; a control conduit branching from said auxiliary pressure conduit to said inlet valve to operate said inlet valve; a throttle restriction in said auxiliary pressure conduit downstream from said control conduit branching; said pump outlet constantly connected to said wheel brake whenever said auxiliary pressure pump is operated to pressurize said outlet, said throttle restriction the only element in said auxiliary pressure conduit affecting outflow from said pump outlet to said wheel brake; a diaphragm valve in said master cylinder pressure conduit upstream from said inlet valve, hydraulically shiftable from a first condition allowing substantially unrestricted flow from said master cylinder to a second condition allowing only restricted flow from said master cylinder by means responsive to a predetermined pressure difference thereacross in said master cylinder pressure conduit.