| 摘要 |
On its arched end face, the head (11) of the drill bit (10) has projections in the form of contiguous conical peaks (14), the tips of which are set with carbide inserts (16). The cone axes (19, 20, 21) of the conical peaks (14) run in different directions and have no common intersecting point. The conical peaks (14) are defined at the foot by valley notches. This design results in very large circumferential surfaces of the conical peaks (14) carrying the carbide inserts (16). The wear of the carbide inserts is thereby reduced and the inserts can easily be reworked. <IMAGE>
|
