STEUERKREIS FÜR EINE ARBEITSMACHINE

摘要

The present invention is a control circuit for a construction machine for using a multifunctional control lever for revolving and boom swing in common and switching pilot pressure via a switching valve (17), comprising: a switch for supplying a switching signal to the switching valve (17); a pressure switch (21) for detecting whether the pilot pressure is output from a remote control valve (19) or not; a switching control circuit (18) for switching a position of switch to a position for a boom swing cylinder when the switching signal is output from the switch and holding the position of switch at the position for the boom swing cylinder when the pilot pressure is detected by the pressure switch, to thereby prevent erroneous operation in switching.