| 摘要 |
PURPOSE:To align an excavator with the center axis of a pipe line to be laid without using a high skill when a sewage pipe or the like is laid underground with the use of an excavation process. CONSTITUTION:A reflector 8 is arranged in a cutter head body 1 having a cutter 6 for excavating a working face so that the reflector 8 is inclined to the center axis 4 of the cutter head body by a predetermined angle. A target 10 is disposed at a position in a tail shield body 2 connected to the cutter head body, being opposed to the reflector and being deflectable relative thereto, and is arranged at a position with a distance of one-half of the swinging radius of the cutter head. A laser beam is arranged being aligned with the center axis of the pipe line, and the cutter head body is deflected so that the reflection of the laser beam irradiated from the reflector is directed to an original point set on the target. |
