| 摘要 |
The invention relates to a percussion drill, preferably for an automatic machine for driving holes in rock, comprising a body 7, 16, 22 with, firstly, a cavity 8, 15, 25 opening out at the end surface of the body directed towards the bottom of the hole which is to be driven, secondly, a part 9 intended for breaking up the bottom of the hole and having a ring-shaped cutting edge 10, 19 with a conical inside 11, and, thirdly, channels 12, 24 connecting the cavity to the driven hole, for removal of the broken-up rock from the cavity, and it is characterized in that the cavity 8, 15, 25 has the shape of a cone whose base surface is directed towards the hole bottom and whose inner side is smooth. <IMAGE> |
