| 摘要 |
A self-drilling anchor dowel has a drill head at one end of the axially elongated dowel and a truncated cone-shaped projection at the other end. The projection fits into an adapter or holder on a drilling device. Immediately following the drill head is a frusto-conical clamping part which tapers inwardly in the direction away from the head. A collar extends laterally outwardly from the smaller diameter end of the clamping part. The outside diameter of the collar is the same as the outside diameter of the drill head. When the dowel is drilled into a receiving material, such as concrete or rock, and the collar enters the borehole formed by the dowel, the collar prevents the borings formed in the drilling operation from being discharged out of the borehole. As the collar continues into the borehole, it compacts the borings which anchor the dowel in the borehole. |
