| 摘要 |
<p>A down-hole pneumatic rotary-percussion hammer drilling apparatus (100) is disclosed. The apparatus includes a drill string (14) for progressively extending into a hole (124) in the earth (81); an elongated housing (4) connected to the drill string; an impact drill bit (104), rotationally coupled to the housing (4), having an engaging surface (122), an earth impacting surface (128), a channel (121), and a plurality of conduits (140, 142) extending from about an exit of the channel to an exit portion (146, 148) of the conduits; a piston (24) within the housing for engaging the engaging surface (122), and a working fluid (82) handler for energizing the piston (24) with a working fluid. The impact drill bit (104) is rotatable about a longitudinal axis, with the channel (121) and the conduits (140, 142) providing a path of flow of the working fluid from the piston (24) to the exit portions (146, 148) of the conduits. The exit portions are displaced from the longitudinal axis (134) and extend generally downwardly and outwardly. The working fluid (32) emerges from the exit portions (146, 148) and effects rotation of the impact drill bit (104) about the longitudinal axis. Associated method and impact drill bit apparatus are also disclosed.</p> |
