| 摘要 |
A rotary drill bit comprising a cutter bit (10) having a plurality of mutually displaced rows (12-17) of cutting means (11) extending in the circumferential direction of the cutter bit (10). The included cone angle ( alpha ) of the cutter bit (10) is larger than 90 DEG and adapted to the mutual positioning of the cutting means (11) on the cutter bit (10) in such a way that it is ensured that repetition of the pattern of the cutting means is avoided. |
