Abstract: The invention provides a screw in which the screw head (1) has a slot (2) in the upper surface of the screw head, an upper peripheral wall (9) of regular planform extending down from the rim of the slot into the screwhead, the upper peripheral wall (9) being generally aligned with the axis of the screw to form a recess (3), a sloping transition surface (15), extending downwardly and inwardly with respect to the lower edge of the upper peripheral wall (9), and a further recess (11) extending downwardly from the lower edge of the sloping transition surface (15), in which the dimensions of the screw head are such that when the screwhead is engaged by a tool (6) having upper (16) and lower (17) engagement sections, and in which the upper engagement section (16) extends downwardly with respect to the axis of the screw to which the tool is to engage and the lower engagement section (17) extends further downwardly, and in which there is at least one protrusion (or rib) (21) on the inside wall (12) of the further rec

Abstract: The invention provides a screw in which the screw head (1) has a slot (2) in the upper surface of the screw head, an upper peripheral wall (9) of regular planform extending down from the rim of the slot into the screwhead, the upper peripheral wall (9) being generally aligned with the axis of the screw to form a recess (3), a sloping transition surface (15), extending downwardly and inwardly with respect to the lower edge of the upper peripheral wall (9), and a further recess (11) extending downwardly from the lower edge of the sloping transition surface (15), in which the dimensions of the screw head are such that when the screwhead is engaged by a tool (6) having upper (16) and lower (17) engagement sections, and in which the upper engagement section (16) extends downwardly with respect to the axis of the screw to which the tool is to engage and the lower engagement section (17) extends further downwardly, and in which there is at least one protrusion (or rib) (21) on the inside wall (12) of the further rec

Abstract: A screw, tool and a system for driving a screw that includes a screw and a corresponding tool is provided. The screw includes a screw head including a slot in the upper surface of the screw head, a tapered recess disposed downwardly of the slot in the screw. The tool includes an upper engagement section which fits within the slot, and a lower engagement section shaped to extend into the tapered recess with a contact surface of an external surface of the lower engagement section in an interference fit with the tapered recess when the upper engagement section is disposed within the slot. The contact surface has a shape which substantially matches any of a plurality of angular inclinations the surface of the tapered recess may have at the interference fit.