| 摘要 |
PURPOSE:To stabilize operation and to make it possible to execute better directional control by expanding a driving jack and a holding jack to continuously drive, and expanding a center-bent jack to turn a front drum frame. CONSTITUTION:A middle drum frame 5 is connected to the rear end of a front drum frame 2 having a cutter 1 in front thereof through a center-bent curved surface 12, and a rear drum frame 8 is fitted backward of the middle drum frame in the front and rear direction in a slidable manner. After that, a driving jack 10 is mounted to the rear drum frame 8, a holding jack 15 connects between the rear drum frame 8 and the middle drum frame 5, and a center-bent jack 16 connects between the middle drum frame 5 and the front drum frame 2. Continuous driving is made by expansion work of the driving jack 10 and the holding jack 15, and the front drum frame 2 is turned with the center-bent curved surface 12 as the center by expansion of the center-bent jack 16 to control a driving direction. |
