| 摘要 |
A vehicle for travel through a conduit includes a forward (1) and a rearward (3) member, each member being provided with a wall-engaging mechanism (50a) for selectively engaging a wall of the conduit to hold the respective member in a stationary position within the conduit. Extensible means such as a hydraulic ram connect the members (1, 3) for relative movement of the forward member (1) toward and away from the rearward member (3). Each wall-engaging mechanism (50a) includes a plurality of legs (66) extendable outwardly form the respective member and a wall-engaging surface on or fixed to each leg, one actuator engages each of the legs for coordinated extension of the legs to bring each wall-engaging surface (5a) into contact with the wall of the conduit. Preferably a rotary cuter (34) is mounted at the front of the vehicle for clearing obstructions in the conduit.
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