COMBINATION OF SCREW AND SCREW DRIVER BIT AND HEADER PUNCH FOR ITS MANUFACTURE

Title:

COMBINATION OF SCREW AND SCREW DRIVER BIT AND HEADER PUNCH FOR ITS MANUFACTURE

Document Type and Number:

WIPO Patent Application WO/2001/050028

Kind Code:

A1

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 of a screw to prevent a conventional damage to the screw and remarkably increasing a working efficiency by always achieving a proper and rapid screw tightening operation even if the cross groove portion of the screw is damaged, wherein the screw is formed so that a bit fitted groove formed of the 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 fitted groove to the center part of a screw neck part, a roughly conical bottom face is formed at a cross center part, the end edge part of the bit fitted groove is formed as a generally vertical end wall part of a specified depth, a groove part with an inclination angle of $g(b) 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 the conical bottom face is formed with a gentle inclination angle $g(a) of approx. 28°.

Inventors:

TOTSU KATSUYUKI (JP)

Application Number:

PCT/JP2000/009199

Publication Date:

July 12, 2001

Filing Date:

December 25, 2000

Export Citation:

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Assignee:

TOTSU KATSUYUKI (JP)

International Classes:

B21K1/46; B21K1/48; B25B15/00; F16B23/00; (IPC1-7): F16B23/00; B21K1/48; B25B15/00

Foreign References:

JPH03292407A	1991-12-24
US2216381A	1940-10-01
JPS5644208U	1981-04-21
JPS5232454A	1977-03-11
JPS4921720B1	1974-06-03
JPH08145024A	1996-06-04

Other References: