BUILDING CONSTRUCTION SCREW

Japanese Patent JP2018017283

A

PROBLEM TO BE SOLVED: To provide a building construction screw for forming a connected part full of tenacity and preventing brittle fracture of ligneous structure by stably decreasing a screw pulling-out yield strength than a strength of a screw main body while holding a yield strength required in design at an architectural structure of ligneous structure.SOLUTION: This invention relates to a building construction screw in which there are provided a bow part becoming an engagement part with a fastening rotary tool at one end part and a shank part formed with a cutting tooth part for cutting into a fastening member and a thread part for screwing into the fastening member at the extremity end at the other end side, and a column-like expanded hole part larger than a diameter of a trough part of the thread and smaller than a diameter near a crest part of the thread part between the cut tooth part and the thread part, the expanded hole part forms an insertion hole that is larger than a diameter of the trough part of the thread part and smaller than a diameter of the crest part of the thread part at an outer peripheral part of the thread part, an engaging margin when the crest part bites into the fastening member is reduced to reduce a contact area between the thread part and the fastening member and a frictional force is reduced to make a stable reduction of a screw pulling-out yield strength of the building construction screw.SELECTED DRAWING: Figure 5

BANDO TOSHIMITSU

JP2016146891A

February 01, 2018

July 27, 2016

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ONCHI SEIBYO KK

F16B25/10

Mitsuhiko Watanabe

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