PRESSURE CONTROL PILOT ACTUATING CONTROL VALVE WITH SAFETY DEVICE

摘要

A pilot operated directional control valve is provided with pressure controlling means responsive to motor line pressure to control the shifting of the control valve to maintain a precisely controlled variable torque in a motor controlled thereby. The pressure controlling means includes constant force centering means for the valve and a piston at each end of the control valve with means communicating motor line pressure to the piston to operate in opposition to a piston subject to pilot control pressure for shifting the valve.