| 摘要 |
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in which a new liner is introduced into an existing pipe behind the cutter or reamer tool, which can be collapsed and withdrawn rearwardly through the newly-installed liner when reaching the end of its run. |
