| 摘要 |
An apparatus for the directional drilling of a bore hole through a solid substrate includes a main bore head (2) mounted for rotation on a flexible main drive shaft (10) The apparatus includes elongate tensioning means (30) extending axially along the flexible drive shaft (10) substantially from the main bore head end of the drive shaft (10) towards a driven end of the drive shaft (10), and tension in the tensioning means (30) tends to urge the flexible drive shaft (10) to bend, thereby altering the drilling direction. |
