| 摘要 |
<p>The present invention relates to a reverse circulation drill bit for ground capable of discharging excavated slime to the outside of an excavation hole by using a fluid supplied from outside. The drill bit (2) changes a direction of the fluid for discharging the slime supplied downward through an outer fluid supply passage (4) to the upper side to discharge the excavated slime on the bottom surface of the excavation hole to the outside through an upward discharge passage (6) of a core unit of the drill bit and includes a connection passage (10) changing the direction of the fluid inside the upward discharge passage (6) and opening-closing control unit (14) (14a, 14b) opening and closing at least one between the fluid supply passage (4) and the connection passage (10). The present invention obtains an effect of rapidly discharging floating slime which is in the middle of being discharged by strong fluid pressure and the excavated slime on the bottom of the drill bit (2) to the ground by directly discharging some or all of the fluid for discharging the slime to the ground through the core unit of the drill bit (2) after changing the direction of some or all of the fluid for discharging the slime to the upper side inside the drill bit (2) without any loss, enables the smooth operation of the drill bit (2) by preventing the slime from getting jammed around the drill bit (2) due to the rapid discharge of the excavated slime, and reduces the fatigue of an operator and increases an excavating speed by automatically operating an excavator by a preset operation cycle value.</p> |
