Threaded bolt, to be used in combination with three specifically shaped securing rings

摘要

The bolt (4) has a threaded shaft (42) and a head (41) of any suitable shape. The lower surface of the head (41) is provided with six inclined radial positioned steps (32) matching the shape of the upper surface of a first securing ring (3). The ring (3) has a plane lower surface with radial grooves (33) to be positioned on top of the work piece (6). A second ring (3) with a plane upper surface and a stepped lower surface (32) is added from below the work piece (6). The arrangement is secured by a nut (5) with a stepped upper surface (51).