| 摘要 |
<p>An improved drill bit for the mining field for use as a roof drill, tunnel drill, rock boring and highway construction, both as a rotary and a rotary percussion drill, which includes a drill head with a diametrical slot positioning a brazed cutting blade, the head having a male drive shank to interfit with a female driver tube and having a maximum axial passage in the driver shank which opens to large fluid passages leading to chip slash openings in opposed quadrants of the drill bit. The drill head position has a hexagonal base portion above the drive shank with circular guiding portions in opposed quadrants adjacent the chip slash quadrant pockets.</p> |
