| 摘要 |
PROBLEM TO BE SOLVED: To provide a ground working machine so designed as to be equipped with a means for altering the rate of actuating a hydraulic cylinder by a specific method so as to ensure a relevant operator to discriminate operational mode, thereby enable steering operability to be improved in turning at a levee edge in a misoperation condition. SOLUTION: This ground working machine which has a hydraulic cylinder functioning to ascendingly/descendingly drive a ground working device mounted on a traveling machine body, a height sensor 14 for detecting the height of the ground working device above the ground, and a solenoid valve V for the hydraulic cylinder, is such one as to be also equipped with a lift control means A functioning to ascendingly/descendingly drive the ground working device through operating the valve V so as to maintain the device at a set height above the ground based on the detection by the sensor 14 and a means 26 functioning to alter the rate of actuating the hydraulic cylinder through changing the duty ratio for pulse drive current with respect to the solenoid valve V. |
