| 摘要 |
<p>A method provided with a working bit (1) for removing drill waste from drilling apparatus driving a tunnel in soil or rock, by means of which drill waste is conveyed by compressed air or water through openings (2) in the drill bit (1) and/or bit holder direct into the drilling apparatus protecting tubes (3, 7) which reach to the bit or bit holder and wherein a lap joint is provided between the protecting tube and the bit or the bit holder to prevent access of drill waste to the outside of the protecting tube.</p> |
