| 摘要 |
<p>The invention relates to a screw having a socket head (16) whose shape is adapted to a concrete drill end provided with a pellet (26) which is disposed on a median longitudinal plane of the end thereof and whose width L is greater than the diameter of the drill body. The inventive screw is characterised in that the socket head (16) comprises a lower part (32) which is adapted to the drill end and a top or through part (34) whose size in a first longitudinal median plane (35.1) is slightly greater than the width L of the pellet (26) and the size in another longitudinal median plane (35.2) is slightly less than the width L of the pellet (26) and greater than the diameter of the drill body.</p> |
