Patent attributes
A screw includes a shank where a thread helix receiving groove winds around the shank and is disposed in the shank. A thread helix is disposed in the thread helix receiving groove where the thread helix has an expandable helix section. The shank has, at the thread helix receiving groove, a wedge flank for radially expanding the expandable helix section as the shank is moved relative to the expandable helix section. The expandable helix section has a helical back and a plurality of expansion fingers projecting axially from the helical back towards the wedge flank. The wedge flank of the thread helix receiving groove is configured for radially displacing the plurality of expansion fingers outwardly as the shank is moved relative to the plurality of expansion fingers.
