SHIELD EXCAVATOR

摘要

PURPOSE:To effectively excavate natural ground by a method in which a milling cutter board to be turned by a drive source fixed integrally with a cutter disc is provided in the space of its front eccentric position by positioning the cutting edge on the back of the cutter tooth. CONSTITUTION:A cutter disc 3 by a drive source 2 is provided on the front end of a skin plate 1, and a propusory jack 5 is provided in the rear side. A rotary cutter 31 for cutting natural ground is projectionally set on the front face 3c of the disc 3. A new segment is assembled between the jack 5 and a newly set pipe T2 to extend the pipe T2. A milling cutter board 33 by a drive source 34 fixed integrally to the disc 3 is provided in the space 3d on the eccentric position of the front face 3c of the disc 3 by lowering the tip of the cutting tooth 33a slightly backwards from the tip of the cutter 31. The abrasion of the reinforcing bar portion of the board 33 can thus be prevented.