| 摘要 |
<p>PROBLEM TO BE SOLVED: To extend a replacement period of a bit of a cutter disk of a shield machine.SOLUTION: At each of both width-directional outer edge parts of each spoke part 2b of a cutter head 2 constituting a mud pressure shield machine 1, a scraper tooth 4s is provided only for an extension-directional outermost peripheral part of the spoke part 2b. In an area other than that, the scraper tooth 4s is not provided and a protection plate PA is provided instead. Consequently, scraper teeth 4s which are much less in durability than other bits like a bit 4b etc., can be greatly decreased, so that the replacement period of bits of the cutter head 2 can be extended. Therefore, a troublesome operation to replace bits that requires time and labor can be reduced, so that long-distance construction by the mud pressure shield machine 1 can be promoted.</p> |
