Patent ID: 6907815

Claim:
A control apparatus of a hydraulic valve for holding load, comprising: a hydraulic pump connected to an engine; an actuator connected to the hydraulic pump; a directional control valve disposed between the hydraulic pump and the actuator and switchable by pilot pressure from a remote control valve and adapted to control a start, stop and direction change of the actuator; a poppet disposed between the directional control valve and the actuator and adapted to preclude momentary drop of load in the actuator; a holding valve block connected to a downstream side of the poppet and having a sub-spool switchable by pilot signal pressure applied thereto and adapted to release upheld load of the actuator; and a drain line adapted to allow hydraulic fluid returned during a switching operation of the sub-spool to flow in a pilot line of the side of a drain corresponding to the opposite side of a pilot line adapted to pressurize the spool of the directional control valve.