| 摘要 |
PURPOSE: To prevent a dangerous condition such as falling-down of a vehicle and steering malfunction due to protrusion of an outrigger resulting from mis- operation by driving the pilot pump serving as the hydraulic source of a pilot electromagnetic switching valve for operating a switching valve through a PTO device, and always taking preference of steering at the time of vehicle running. CONSTITUTION: By selecting running with an operating switch, a controller 26 outputs a command to an operating part 10 to release the connection of a PTO device 3, so that a pilot pump 6 has no rotation, thus generating no oil pressure. A switching valve 22 is kept in its neutral position 1 by a spring 22c and connected to a steering circuit 23. Even if a pilot electromagnetic switching valve 9 is switched due to mis-operation, therefore, the switching valve is kept in the neutral position 1. For carrying out quantitative work, a command is outputted to an operation part 10, and the PTO device 3 is connected, so that the switching valve 22 is switched to shut down the steering circuit 23 and supply pressure oil to respective outrigger cylinders 24 through a switching valve 25 for outrigger. |
