| 摘要 |
PURPOSE:To make easier underground excavation work and usual straightforward excavation work by a method in which a valve connecting or interrupting a level cylinder and a boom cylinder is provided, and the oil pressure of the level cylinder is allowed to escape to a tank during the interruption period. CONSTITUTION:A boom 3 is pivotally attached to the front of a rotor 2 on a traveler 1 in a rocking manner by a boom cylinder 4, and an arm 5 is pivotally supported on the tip of the boom 3 in a vertically rocking manner by an arm cylinder 6 and a level cylinder 11. A bucket 7 is also pivotally supported on the tip of the arm 5 in a vertically rocking manner by a bucket cylinder 8. A valve 14 through which the oil pressure of the level cylinder is allowed to escape to a tank when the rod side chamber and bottom side chamber of the boom cylinder 4 are led to or interrupted with the rod side chamber and bottom side chamber of the level cylinder is provided. Either underground excavation or straightforward excavation work can thus be easily performed. |
