| 摘要 |
1,249,143. Boring earth and rock. CEMENTATION CO. Ltd. 26 Aug., 1969 [13 Dec., 1968], No. 59372/68. Heading E1F. A reamer bit comprises a body 1 connected to a drill rod 3 and resilient elements 4 bendable to lie along the body. The bit is inserted in a borehole and rotated so that the elements 4 resiliently engage the walls and produce a local enlarging Figs. 2-4 (not shown). Pressure fluid, which may be air, is supplied to orifices 9 in a tube 6 which may be attached to the side of the body 1 or may extend within it. The elements 4 are formed from wire rope, spring steel or nylon, and may be arranged in a spiral. |
