Fastener head with grooves to receive driving tool ribs

Claim 1

A FASTENER FOR USE IN A DRIVING TOOL OF THE TYPE HAVING A DRIVE TRACK FORMED WITH A PAIR OF SPACED APART RIBS DISPOSED ON OPPOSITE SIDES OF AND FORMING A CENTRAL SHANK RECEIVING GUIDEWAY, SAID FASTENER COMPRISING A SHANK HAVING A FLAT UPPER END FACE NORMAL TO THE LONGITUDINAL AXIS OF SAID SHANK AND A GENERALLY T-SHAPED HEAD INTEGRALLY FORMED WITH SAID SHANK AT THE UPPER END THEROF, SAID HEAD INCLUDING OUTWARDLY EXTENDING PORTIONS FORMED TO EXTEND OUTWARDLY FROM OPPOSITE SIDES OF SAID SHANK AND GENERALLY TRANSVERSE THERETO, EACH OF SAID PORTIONS HAVING A FLAT UPPER SURFACE COINCIDENT WITH THE FLAT UPPER END FACE OF THE SHANK AND BEING SUBSTANTIALLY EQUAL IN WIDTH TO THE DIAMETER OF SAID SHANK, EACH OF SAID EXTENDING PORTIONS ALSO INCLUDING A PAIR OF SIDE FACES EACH HAVING A PORTION THEREOF ALIGNED GENERALLY IN A PLANE TANGENT TO THE OUTER PERIPHERAL SURFACE OF SAID SHANK, SOME OF SAID SIDE FACES ALSO INCLUDING A GROOVE FOR RECEIVING THE RIB OF SAID DRIVE TRACK AND EXTENDING DOWNWARDLY FROM THE FLAT UPPER SURFACE OF SAID EXTENDING PORTION THROUGH SAID HEAD, EACH OF SAID GROOVES DISPOSED ADJACENT SAID SHANK AND HAVING A PORTION OF ITS SURFACE SUBSTANTIALLY CONFORMING TO THE SHAPE OF AND COEXTENSIVE WITH THE ADJACENT OUTER PERIPHERAL SURFACE OF SAID SHANK.