Anchor nail fastener having chisel point

Claim 1

In an anchor nail fastener comprising, in combination, an elongated tubular member of resistingly deformable metal having upper and lower anchor ends to be driven lower end first into a workpiece, means adjacent the upper end of the member for limiting penetration of the member relative to the workpiece, the wall of said tubular member provided with a side opening aperture spaced upwardly from the lower end with a portion of the wall extending inwardly and upwardly from the lower edge of the aperture across the interior of the tubular member to the opposite interior wall face thereof to provide an upwardly facing surface for deflecting the point of a nail driven downwardly through the tubular member laterally outward through said aperture, the improvement which comprises said tube being formed of hardened carbon steel and having a hollow chisel point characterized by opposite halves of the tip of said lower end that extend in a downwardly diminishing spaced relation to form a knife edge at said chisel point along the bottom edges of said opposite side halves, said opposite side halves substantially symmetrically mating along said knife edge, said side opening aperture being open to the side of one of said opposite side halves, said knife edge having a thickness less than twice that of the wall of said chisel point, and the angle of the opposite halves of the tip acting as a wedge as the tube is driven lower-end-first into a workpiece.