| 摘要 |
PROBLEM TO BE SOLVED: To provide a horizontally drawing device having simple control constitution, easy in operation and low in cost. SOLUTION: A shuttle valve 25 is connected to the pilot port of a boom direction switching valve 11, the output side ports of a boom remote control valve 17 and solenoid valves 18, 19 are connected to the input side port of the shuttle valve 25, the solenoids of the solenoid valves 18, 19 are connected to the output side of a controller 10, and a crane mode selection button 22 and an automatically horizontally drawing mode selection button 23 are connected to the input side of the controller 10. In the case where the controller 10 selects a crane mode and an automatically horizontally drawing mode, the solenoid valves 18, 19 are controlled so as to hold crane height constant by lifting operation or lowering operation of a boom 1 at the time when opening operation or closing operation of an arm is performed.
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