Abstract: Provided is a hydraulic valve including a valve body having a first port, a second port, and a pilot port, and a piston movable in the valve body to an open position by a pilot pressure flowing through the pilot port that acts on a portion of the piston to move the piston away from a valve seat in the body to allow fluid flow between the first and second ports. The piston is then movable to the closed position by a resilient member in the absence of the pilot pressure. In this way, during an event such as a power failure of a vehicle when the pilot pressure is unavailable, the valve is closed to prevent fluid draining from a hydraulic function to prevent movement of the function without using a mechanical locking device.

Abstract: Provided is a hydraulic valve including a valve body having a first port, a second port, and a pilot port, and a piston movable in the valve body to an open position by a pilot pressure flowing through the pilot port that acts on a portion of the piston to move the piston away from a valve seat in the body to allow fluid flow between the first and second ports. The piston is then movable to the closed position by a resilient member in the absence of the pilot pressure. In this way, during an event such as a power failure of a vehicle when the pilot pressure is unavailable, the valve is closed to prevent fluid draining from a hydraulic function to prevent movement of the function without using a mechanical locking device.