| 摘要 |
PURPOSE: To reduce the wear of a cutter bit and improve the durability. CONSTITUTION: A base 11 provided on a cutter head 1 has a shaft body 11b inclined forward on the shaft center side of a shield body, and the shaft body 11b has an inversed conical rotary cutter body 12 having cemented carbide tip 12b buried around the front part. By the rotation of the rotary cutter body 12 caused by the turning speed difference between the inner circumferential side and the outer circumferential side, the sliding friction is reduced to reduce the wear, and since the cutting edge part in which the cemented carbide tip 12b is buried is long, compared with a conventional one, the excavation of a long distance can be performed. |
