Title:
WOOD SCREW AND SCREW FORM ROLLING FLAT DIE
Document Type and Number:
Japanese Patent JP2016217510
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a wood screw that can be easily screwed into a hard wood by a low torque, and have sufficient fastening force after screwing.SOLUTION: In a wood screw 1 having a tapered pointed end 4 at an extremity end of a cylindrical shank 3, a preceding screw thread 5 having a triangular section with a prescribed lead angle θ, a pitch P and a nominal diameter [d] is formed over a segment from the extremity end of the pointed end 4 to the extremity end of the shank 3, and a behind screw thread 7 having substantially the same lead angle θ, pitch P, nominal diameter [d] as those of the screw thread 5 and sectional shape is formed from a part near the extremity end of the shank 3 to an intermediate portion or a part near a rear end. The preceding screw thread 5 and the behind screw thread 7 are displaced to each other by a half pitch so as to form a double-start thread at the part near the extremity end of the shank 3 within a range of 1 pitch to 2 pitches.SELECTED DRAWING: Figure 1
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Inventors:
HIRATA MASAHIRO
Application Number:
JP2015105435A
Publication Date:
December 22, 2016
Filing Date:
May 25, 2015
Export Citation:
Assignee:
HIRATA NEJI KK
International Classes:
F16B25/04; B21H3/06; F16B25/10; F16B35/00
Attorney, Agent or Firm:
Patent Business Corporation Ark Patent Office
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