DOUBLE-SCREW STRUCTURE

Japanese Patent JP2018080819

A

PROBLEM TO BE SOLVED: To provide a double-screw structure in which a general specification first screw and a special second screw which is formed by deforming a multiple-thread screw at a thread of the first screw with a lead different from that of the first screw are formed, and which is used as a loosening fastener for preventing the lack of the rigidity of a screw part.SOLUTION: In this double-screw structure 1, a first screw (S1) and a second screw (S2) which are different in leads are formed at a double-screw part. The double-screw structure has a loosening prevention function, and does not cause the lack of the rigidity of the screw part. The screw part is constituted of the first screw (S1) composed of a trapezoidal screw having a standard pitch P, and the special second screw (S2). The second screw (S2) is continuously formed at a thread of the first screw (S1), and its cross section shape of a screw groove is the same or substantially the same as that of the first screw (S1). The second screw is the same in a torsional direction, has a prescribed multiple number n of leads (L=n*p) of the standard pitch P, and the number of threads in the cross section shape is less than that of the multiple-thread screw having the trapezoidal screw by one or more.SELECTED DRAWING: Figure 2

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SHINBUTSU TOSHINAKA
TAKEMASU MITSUIE
AMANO SHUICHI

JP2016225426A

May 24, 2018

November 18, 2016

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TENZO GIJUTSU KENKYUSHO CO LTD

F16B35/00; B21H3/06; F16B33/02; F16B39/30

Motonari Tomisaki
Machida Mitsunobu

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