| 摘要 |
<p>PURPOSE:To raise the efficiency of operations by a method in which the pilot pressure of a pilot circuit on the boom-rising side is directed to one of the ports of a shuttle valve connected to a control valve for slewing through a switch valve, and a pilot valve is connected to the other port. CONSTITUTION:Shuttle valves 11a and 11b are provided for the pilot pipelines 10a and 10b of a slewing pilot valve 8 and the pilot pressure is directed to the pilot ports of a slewing control valve 4. The pilot port of a switch valve 15 is connected to the branched pipeline 14c of the pilot pipeline 14a of a booming pilot valve 12 and the secondary side port is connected to the input side port of the valves 11a and 11b. Since the acceleration capability of slewing the valve 4 can be optionally selected, the moving locus of the bucket can be optionally altered.</p> |
