| 摘要 |
PURPOSE:To make it possible to exchange the existing main cutter bit with a spare cutter bit easily within a short period of time in the case the main cutter bit is worn out. CONSTITUTION:A plurality of spokes 1a are provided to the front of a cutter head 1 provided to the front of a shield body driven into the ground in a rotatable manner in the radial direction, and in a shield excavator mounting a large number of cutter bits to both sides of the spokes 1a, a plurality of cutter bit bearing members 5 mounting a main cutter bit 6 and a spare cutter bit 7 to both sides of the spokes 1a are borne through bearing shafts 4 in a rotatable manner. one end of a link 8 is mounted to each of the bearing shafts 4 and, at the same time, the other end of the link 8 is connected to a driving means 12 through an interlocking link 9. In the case main cutter bit is worn out, the spare cutter bit 7 is projected by turning a cutter bit bearing member 5 by the driving means 12. |
