| 摘要 |
1514022 Percussion drill R MONTABERT 1 July 1976 [4 July 1975] 27415/76 Heading B4C A percussion drill has a socket 8 providing a fluid tight seal between an inlet tube 3 supplying fluid for clearing away debris from the drill tip and a hollow drill rod 4, the socket being engageable at one end on an end of inlet tube 3 and has a bore 11 complementary in shape to that end of tube 3, the socket having an outer metal casing 9 locatable in a bore in drill rod 4 and a resilient member 10 secured in casing 9 and defining, at the other end of the socket a flared part forming a flexible annular lip 12 which when uncompressed has a diameter larger than that (D) of the drill rod bore. Drill rod 4 is struck by piston 1. In the embodiment of Fig. 1 the member 10 is elastomeric and defines a truncated conical bore 11 opening on to said one end of the socket. The bore of the drill rod has a flared section 6 of truncated conical shape. In the embodiment of Fig. 3, not shown, the outer metal casing 9 is extended beyond the resilient member 10 at said one end of the socket and has an inner wall (13) of truncated conical shape. The bore of the socket is defined partly by wall (13) and partly by a bore (14) of truncated conical shape in the resilient member, so that the inlet tube engages a metal surface and a resilient surface of the socket. Preferably the angle of opening of the resilient bore (14) is greater than that of the metal bore (13). The fluid may be water or air. |
