| 摘要 |
PURPOSE: To simplify a device, and enhance efficiency by positioning an over cutter in its position by advancing the over cutter in the radial direction of a cutter head at outbreak construction work time of a tunnel, and optionally pulling in the over cutter at ordinary excavation propelling time. CONSTITUTION: A disk cutter 7 advances and retreats in the radial direction of a cutter head 6 by extension-contraction of a hydraulic jack 8, and the disk cutter 7 is rotatably supported on the tip of an extensible-contractible rod 9 of the jack 8. At excessive excavation time, the driving disk cutter 7 is positioned outward in the radial direction of the cutter head 6, and accurate excessive excavation work is made possible to excavating raction from bedrock. A lock of the disk cutter 7 is released, and the disk cutter 7 is moved inward in the radial direction of the cutter head 6, and ordinary excavation propelling construction work is performed. Radial directional driving, a lock and a release of the lock of the cutter head 6 of the disk cutter 7 act at the same time, and mutually avoid a check of the other actuation, and are smoothly actuated. Particularly, when actuation in this order is automated, labor can be reduced. |
