| 摘要 |
The present invention relates to a percussive down-the-hole hammer, a drill bit and a foot valve. The drill bit includes a body having a front drilling face, a central passage extending from a rear end of the body in a direction towards the drilling face to conduct flushing medium to the drilling face. The rear end includes an impact surface surrounding the passage. The central passage is adapted to receive a foot valve to transfer pressurized air through the drill bit. The foot valve and the central passage include insertion stop means and major extraction stop means for the foot valve. The insertion stop means are provided at a distance from the major extraction stop means. |
