Actuator for an antiskid brake system

Claim 1

An actuator for an antiskid brake system for a wheeled vehicle, said brake system having a driver operated master brake cylinder for developing brake pressure and a wheel brake cylinder, a fluid passage between said master brake cylinder and said wheel brake cylinder, means for reducing instantaneous pressure in said wheel brake cylinder, said pressure reducing means communicating with said wheel brake cylinder, fluid pump means communicating with said pressure reducing means for pumping fluid pressure thereto and actuating the same to modify the mode of response of said wheel brake cylinder to a braking effort applied to said master brake cylinder, an electric motor means for powering said pump means, and a wheel slip detecting circuit means for energizing said motor means whenever a predetermined wheel slippage occurs, said pressure reducing means including an actuator having a piston, said piston being displaced when said motor is activated, one side of said piston communicating with said brake cylinder whereby the effective volume for the fluid in said passage is increased as said piston is displaced and a oneway check valve means in said passage for interrupting communication between said wheel brake cylinder and said master brake cylinder when said piston is activated by control pressure developed by said fluid pump means and establishing fluid communication between said wheel brake cylinder and said master brake cylinder when said actuator assumes a passive condition.