To provide an operating circuit for a working machine capable of positively preventing malfunction after cut-off by an operation stop device is released by the operation of a gate lock lever.
The operating circuit for the working machine is provided with a pilot pump 3, and the operation stop device disposed in a first pilot line 12 allowing an arm operating device 10 and a traveling operating device 11 to communicate with each other, and having the gate lock lever 20 operated when getting out of a vehicle to stop the supply of secondary pressure to an arm directional control valve 8 and a traveling directional control valve 9 from the arm operating device 10 and the traveling operating device 11 to thereby put an arm cylinder 6 and a traveling motor 7 out of operation. The first pilot line 23 comprises an impeding means including a solenoid selector valve 24 and a switch 25 and capable of impeding the supply of secondary pressure from the arm operating device 10 to a control chamber of the arm directional control valve 8.
TSURIGA YASUTAKA
KAWAMOTO JUNYA
TAKAHASHI KIWAMU
Ichiro Suzuki
Hirohiro Ichimura
Kazunori Satake