Patent ID: 9707946
Date: 2017-07-18
CPC Classifications: B60T,F15B

Claim:
1. An actuator comprising: a housing defining a low pressure chamber and a high pressure chamber; a low pressure piston assembly which is in the low pressure chamber and has a contact surface; a high pressure piston assembly which is in the high pressure chamber and which moves jointly with the low pressure piston assembly and forward along a longitudinal axis in response to forward movement of the low pressure piston assembly; and an unloader valve in fluid communication with the low pressure chamber and having an elongated stem offset and parallel to the longitudinal axis that moves between a closed position and an open position which allows hydraulic braking liquid to flow out of the low pressure chamber through the unloader valve; wherein the contact surface engages and pushes the elongated stem of the unloader valve longitudinally from the closed position to the open position during forward movement of the low pressure piston assembly along the longitudinal axis so that hydraulic braking liquid flows longitudinally out of the low pressure chamber through the unloader valve.