| 摘要 |
<p>The invention relates to a drill with a drill shank (1), especially a screw shank with a self-tapping thread (18) and a forked drill bit (10) of hard material at the opposite end of the shank to the driving end which is inserted into a holder in the shank (1) having two diametrically opposite grooves (3, 4) in the shank to accept prongs (13, 14) in the drill plate (10). The shank (1) terminates bluntly in a substantially radial end surface from which the grooves (3, 4) run to the driving end in such a way that only the prongs (13, 14) of the drill bit (10) axially pressed into the grooves both lock said bit in a self-clamping manner on the shank (1) and transmit the torque from the shank (1) to the drill bit (10).</p> |
