Tamper resistant screw and accompanying screwdriver

摘要

The invention relates to a profile of a screwdriver engagement opening located on a screw and to an accompanying engagement profile of a screwdriver which has a negative shape that essentially corresponds to the shape of the engagement opening. A central protrusion (3) projects from the essentially level bottom (1) of the engagement opening (2) and is surrounded by an annular free space (4). Radial recesses (5) originate from said annual free space (4) with flanks (6) that run in an approximately radial direction. Said flanks (6) each open into a face (7) of the recess (5) that is located approximately on a circumferential line. According to the invention, the face (7) constructs an opening section (9) that is next to the edge (8) of the opening and constructs a cylindrical section (10) that is next to the bottom (1). In addition, the central protrusion (3) has a dome-shaped contour.