| 摘要 |
PROBLEM TO BE SOLVED: To provide a spherical bit that can be installed at a narrow cutter body while facilitating the replacement of a cutter bit. SOLUTION: The sphere type bit 1 comprises a spherical bearing seat 7 having a through hole 6 through the natural ground 5 side, provided at the cutter body 3 of a shield machine 2 and exposed to the natural ground 5 side; a sphere 9 turnably provided at the spherical bearing seat 7; and the cutter bit 10 provided retractably in the sphere 9 and formed to be replaceable. The sphere 9 is formed with a through hole 8 penetrating in a diametrical direction, and the cutter bit 10 is slidably provided in the through hole 8 to be protrudable onto the natural ground 5 side and to be pulled out of an opening on the opposite side to the natural ground 5 side. The sphere 9 is provided with a driving means 27 taking reaction from the sphere 9 to slide the cutter bit 10, and the spherical bearing seat 7 is formed with a cover face part 11 closing the natural ground 5 side opening of the through hole 8 when the sphere 9 is turned by a predetermined angle. COPYRIGHT: (C)2008,JPO&INPIT |
