Screw head profile

摘要

The centre face (3) of the slot (2) extends to the rim, via angled triangular areas, as opposed to the flanks of the slot which are bevelled where they contact the screw head faces to accept the respective screwdriver. The slot preferably leaves the screw head surface intact at the periphery, or else the slot is designed in symmetrical cruciform shape, the slot sides being bevelled at an angle where they contact the face. The slot may run straight, at right angles to the insertion depth at the triangular rim area, as opposed diagonally to the insertion in the centre part of the slot. The supporting faces of the screwdriver itself may be, in turn, bevelled at the sides and the support faces of the screw head are similarly bevelled.