Patent ID: 6742438
Filing Date: 2004-06-01
Classification: E02F,F15B

Abstract:
A hydraulic valve control device for heavy construction equipment, comprising:a hydraulic pump; an actuator connected to the hydraulic pump and driven upon hydraulic fluid supplies; a main spool mounted in a path between the hydraulic pump and the actuator and switched upon a pilot signal pressure to control start, stop, and direction switching of the actuator; a poppet mounted to be opened and closed at a path between the main spool and the actuator and preventing the actuator from being descended; a spool mounted between a back-pressure chamber and a feedback path of the poppet and switched upon an application of the pilot signal pressure to communicate the back-pressure chamber with a path on an outlet of the main spool; said spool having a minute through hole orifice defining a fluid flow-reducing path connecting the back-pressure chamber and the spool and communicating the back-pressure chamber with the feedback path upon the switching of the spool to reduce hydraulic fluid drained from the actuator.