OBSTRUCTION CUTTING DEVICE FOR SHIELD MACHINE AND METHOD THEREOF

摘要

PURPOSE: To cut an obstruction such as concrete, reinforcement or a steel frame without changing the constitution of the bits and the like of a conventional shield machine by a large margin and dispose of cut pieces smoothly. CONSTITUTION: An obstruction cutting device for a shield machine consists of excavating bits, cutting bits 16 and protective bits 18 plurally arranged with radial spaces at a cutter bead 12 rotated face to face with the working face. The excavating bits 14 are so arranged to cut the whole working face by the rotation of the cutter head 12. The cutting bits 16 are formed in circular arc shape concentric with the cutter head 12 and arranged in such a way that the excavating bits 14 pass between the radially adjacent cutting bits 16. The protective bits 18 are positioned on the rotational loci of the cutting bits 16 and provided movably forward and backward between the protecting positions where the tips are positioned in front of the cutting bits 16 and the stand-by positions where the tips are positioned behind.