Patent ID: 8449046

Claim:
A two stage master cylinder comprising a primary piston, a secondary piston, a push actuator mechanically engaging said primary piston and pushing both pistons for moving said pistons to create a hydraulic fluid flow and pressure at a power outlet of said master cylinder; and a by-pass control valve for opening a venting outlet associated with said primary piston upon actuation of said master cylinder and the pressure of the hydraulic fluid at said power outlet reaching a predetermined pressure; and wherein said master cylinder includes a first stage where both said primary and secondary pistons move with said push actuator to displace hydraulic fluid through said power outlet and a second stage where both said primary and secondary pistons continue to be displaced by said push actuator and movement of said secondary piston determines the amount of hydraulic fluid displaced through said power outlet; wherein said by-pass control valve includes an adjustable spring bias allowing adjustment of said predetermined pressure; and wherein said venting outlet includes a vent channel sized to throttle the venting of hydraulic fluid with said vent channel including an adjustable throttling valve.