CONSTRUCTION MACHINE FLOAT VALVE

摘要

Disclosed is a construction machine float valve capable of removing a spool stick phenomenon if this occurs in the process of flattening and leveling work. According to the present invention, provided is a construction machine float valve comprising: a valve block having a first actuator port and a second actuator port communicating with a large chamber and a small chamber of a hydraulic cylinder of a work device, and a tank port alternatively communicating with the first actuator port and the second actuator port; a holding poppet provided to be opened or closed to a path for connecting the first actuator port to the second actuator port; a spool provided in the valve block so as to be convertible and converting the holding poppet to a holding function-releasing position so as to open the path at the time of the spool conversion; a boom-up signal pressure port to which boom-up pilot pressure is applied so as to restore the spool to a neutral position if the spool has not been restored to the neutral position when the boom-down pilot pressure is released; a piston pressing the spool by the boom-up pilot pressure applied to the boom-up signal pressure port so as to restore the spool to the neutral position; and a drain port for draining hydraulic oil from a pressure chamber if the piston is pressed by the boom-up pilot pressure and if the spool is converted by the boom-down pilot pressure.