| 摘要 |
<p>A drilling apparatus furnished with one hammering and rotating drill bit (4), where a hammering machine (1) producing strokes to the drill bit is behind the drill bit (4) and there is on the outer shell of the drill bit a joint between protective tube (2) and drill bit (4). The joint between hammering machine (1) and drill bit (4) can be opened and locked only by revolving and/or moving the hammering machine and the drill bit (4) is suspended to its place in protective tube (2) by means of joint (8) when the hammering machine (1) is removed from the drilling position.</p> |
