| 摘要 |
<p>A cutter or reamer device (20) has two relatively movable parts (22, 24), the latter of which has means by which it can be drawn by traction from a leading end (26) or thrust by a push rod (12), and the latter of which has arms (33) which, upon relative thrust between the two relative movable parts (22, 24) can be moved from a collapsed position to a laterally extended position in which they apply a force to a pipe through which the device is being forced in order to fracture it or enlarge its diameter (if collapsed). A method of reinstating drainage pipes is also described, in which a new liner is introduced into an existing pipe behind the cutter or reamer tool, which can be collapsed and withdrawn rearwardly through the newly- installed liner when reaching the end of its run.</p> |
