| 摘要 |
<p>Apparatus for use in the laying and/or replacement of pipes under ground comprises a casing (1), a frusto-conical impact member (2) secured to one end of the casing and adapted to form an underground passage for the casing when the apparatus is being driven through the ground, a piston (7) reciprocally mounted in the casing and arranged to be driven by a source of compressed air or other fluid to engage the impact member (2) with a series of impacts to drive said member and the casing through the ground and a control valve member (11) adapted to be connected to a source of compressed air or other fluid and arranged to reciprocate the piston in the casing by means of said compressed air or other fluid. A pipe fitting (31) is connected to a tubular spacer member (23) which is mounted on the other end of the casing (1), said pipe fitting being adapted to be clamped to the leading end of a pipeline (29 and/or 30) which is to be laid in the underground passage formed by the impact member (2). The connection between the pipe fitting (31) and spacer member (23) includes a flanged sleeve (25) whichpermits relative rotation between the pipe fitting and the casing.</p> |
