| 摘要 |
PURPOSE:To prevent a bent pipe from being extremely twisted and improve excavating precision, by providing the front end of the bent pipe, with a jet motor which can be driven with high pressure water and can be rotated forward or reversely, and by driving an excavating bit. CONSTITUTION:At the tip of a bent pipe 1 to be laid, an excavating device 2 having a jet motor 3 which can be driven by high pressure water and can be rotated forward or reversely, and an excavating bit 4 driven by the motor 3 are fitted. Then, by a change-over valve 9, the rotational direction of the jet motor 3 is converted at proper intervals, and the excavating bit 4 is rotated forward or reversely to perform excavation. Besides, driving water and sludge which are jetted from the jet motor 3 are mixed with each other, and are taken in the excavating device 2, and are attractively discharged to an external section through a sludge pipe 16 in the bent pipe 1. As a result, an equipment can be miniaturized, and outbreak can be reduced. |
