STRUCTURE FOR COUPLING BETWEEN A SCREW HEAD AND A TIGHTENING TOOL

摘要

Structure for coupling between a screw head and a tightening tool, in which the free end wall of the head (1) of the screw (2) comprises a recess (3) with a curved concave surface, and the tip of the tool (5) ends in a protuberance (6) with a curved convex surface. The recess has internal axial projections (4) and the protuberance (6) has meridional grooves (7).