Combination of screw and screw driver bit and header punch for its manufacture
OwnerKatsuyuki Totsuinventor
Life of this patent
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Abstract
A combination of a screw and a screw driver bit and a header punch for its manufacture capable of effectively preventing a come-out phenomenon of the screw driver bit by improving the structure of a groove part in a cross groove part in a cross groove of a screw to prevent a conventional damage.
Claims6
A screw which is formed so that a bit-fitting groove formed of a cross groove is provided in a screw head part, a specified tilted groove part is formed in the direction from the end edge part of the bit-fitting groove to the center part of a screw neck part, and a roughly conical bottom face is formed at a cross center part, characterized in that the end edge part of said bit-fitting groove is formed as a generally vertical end wall part of a specified depth, in that a tilted groove part with an inclination angle β of about 45°0 is formed in the direction from the lower edge part of the end wall part to the conical bottom face at the center part of the screw neck part, and in that said conical bottom face is formed with a gentle inclination angle α of approximately 28°.
Dependencies are inferred from the claim text.