US Patent 9302375 Driving feature

Rotationally symmetrical force-application means with, as viewed axially, a star-shaped outer contour or inner contour, for connecting elements, wherein the individual arms of the star are designed as pointed arcs, of which the outer points lie on a common outer circle, wherein an associated counterpart, in particular a bit, insert or screw head, has a mating contour which is adapted to the contour of the force-application means such that the radii of the flanks of the force-application means and the counterpart end up butting against one another in such a manner as to achieve a planar pressing surface.