Nail having a shearing point

Claim 1

A NAIL FOR USE IN FIBROUS MATERIALS AND THE LIKE, COMPRISING, A SHANK AND A HEAD, A POINTED DRIVING END ON SAID SHANK OPPOSITE SAID HEAD, FIRST AND SECOND PORTIONS ON SAID SHANK WITH SAID FIRST PORTION ADJACENT SAID DRIVING END, A PLURALITY OF ANNULAR SHEARING WALLS OF EQUAL DIAMETERS ON SAID FIRST PORTION EACH GENERALLY PERPENDICULAR TO THE AXIS OF SAID SHANK AND FACING SAID DRIVING END, A SHEARING WALL BEING NEXT ADJACENT TO THE BASE OF SAID POINTED END, CONICAL JOINING WALLS ON SAID FIRST PORTION JOINING THE CREST OF ONE SHEARING WALL WITH THE ROOT OF THE NEXT SHEARING WALL, A PLURALITY OF ANNULAR SHOULDER WALLS OF EQUAL DIAMETERS ON SAID SECOND PORTION EACH GENERALLY PERPENDICULAR TO SAID AXIS AND FACING SAID HEAD, AND CONICAL JOINING WALLS ON SAID SECOND PORTION JOINING THE CREST OF ONE SHOULDER WALL WITH THE ROOT OF THE NEXT SHOULDER WALL, SAID SHEARING WALL ADJACENT SAID POINTED END HAVING A DIAMETER LARGER THAN THE BASE OF SAID POINTED END AND SUBSTANTIALLY EQUAL TO THE DIAMETER OF SAID SHOULDER WALLS, THE JUNCTURE OF SAID FIRST AND SECOND PORTIONS BEING DEFINED BY A V-SHAPED ANNULAR GROOVE FORMED BY THE INTERSECTION OF THE OPPOSITELY FACING JOINING WALLS, WHEREBY IN USE THE DRIVING END PARTIALLY SEPARATES AND RADIALLY COMPRESSES THE FIBERS OF THE MATERIAL INTO WHICH THE NAIL IS DRIVEN WITH SAID SHEARING WALLS SHEARING THE PARTIALLY COMPRESSED FIBERS AND THEN SAID SHOULDER WALLS GRIP THE FIBERS AFTER PARTIAL EXPANSION THEREOF.