| 摘要 |
PCT No. PCT/GB93/02499 Sec. 371 Date Aug. 9, 1995 Sec. 102(e) Date Aug. 9, 1995 PCT Filed Dec. 3, 1993 PCT Pub. No. WO94/13926 PCT Pub. Date Jun. 23, 1994A mole launcher which has a hydraulically powered, double-acting piston and cylinder unit to push or pull a slider. The slider carries a drill head connected to a drill string. The other end of the drill string carries a mole to bore an underground passage. By releasably locking the slider to the front of the launcher, the cylinder can be moved between a first position in which it projects beyond the chassis of the launcher, and a second position in which it is placed only within the length of the chassis. Thus, the mole launcher is considerably shorter in its transportation state than in its operating state.
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