| 摘要 |
PURPOSE:To smoothly excavate the ground by a method in which when the excavating resistance of a hydraulic cylinder for excavation of a bucket, etc., exceeds a set pressure value, the bucket cylinder is vibrated based on a signal indicating no stroke end and a signal for cylinder extension. CONSTITUTION:A pilot pressure working direction control valve 11 is provided in the circuit between the hydraulic cylinder 10 for excavation of a bucket and a hydraulic pump 16, and a solenoid valve 14 and a proportional control valve 15 are provided between the control valve 11 and a pilot hydraulic pump 22. Under the condition that a reciprocally movable control switch 30 is closed, an extension signal for the cylinder 10 is sent out, and only when a signal indicating no stroke end from a stroke detector 31 and a signal showing that load exceeds a set value from a load detector 32 are sent out, the solenoid valve 14 is switched in a short time period, and the cylinder is vibrated to vibrate the excavator, e.g., bucket, etc., thereby permitting excavation to be smoothly performed. |
