Apparatus for preventing the locking of a wheel

Claim 1

A wheel lock prevention apparatus comprising: (a) a master cylinder; (b) a brake unit for braking a wheel in response to actuation of said master cylinder; (c) a main passage connected between said master cylinder and said brake unit for transmitting a brake fluid pressure; (d) a first normally-open solenoid-operated valve disposed in said main passage which is independent of brake fluid pressure for operation; (e) a reservoir mechanism including a movable reservoir piston for storing a brake fluid and urged in one direction by a spring force; (f) a second normally-closed solenoid-operated valve having one end connected to said main passage between said brake unit and said first normally-open solenoid-operated valve and an opposite end connected to said reservoir mechanism; (g) a pump mechanism disposed between said reservoir mechanism and said brake unit for returning the brake fluid from said reservoir mechanism to said brake unit; (h) means for opening said second normally-closed solenoid-operated valve in response to a first signal indicative of detected wheel locking; (i) means for generating a second signal indicative of movement of said reservoir piston for storing brake fluid; and (j) an electric circuit for actuating said pump mechanism when said first signal is not produced and said second signal is generated.