| 摘要 |
PURPOSE:To stabilize the turning speeds of a slewing base and an operating arm by providing a detector to detect the operations of an operating lever for a rotary operating valve and an interrupting valve to interrupt the confluence of pressure oil to a vertically rocking operation valve on the basis of information from the said detector. CONSTITUTION:In the center bypass of a rotary operation valve V9 to ratationally operate a slewing base 2 or an operating arm 15, a confluence pipeline 12 is provided such that pressure oils are joined to the vertically rocking operation base V6 of the arm 15. A sensor 23 to detect the operational condition of an operating lever 22 for the valve V9 is provided. During the operation of the lever 22 on the basis of the information from the sensor 23, the confluence of pressure oils to the base V6 is interrupted by a confluence interruption valve 24 provided to the pipeline 12. The slewing base 2 or the operating arm 15 can thus be stably operated rotationally, and the inching operability during the fine operation period can also be kept under good condition. |
