To provide an automatic tightening means which can surely prevent the generation of a clearance corresponding to the degree of change with time even if performing rotation-preventing treatment such as applying rust-preventing coating on the surfaces of fasteners such as a bolt and a nut after they have been attached.
The automatic tightening means is mounted between one end side of the bolt 1 and the nut 2 for fastening and securing wooden beams A, B to each other, and the wooden beams A, B, thereby automatically compensating to prevent the generation of a clearance between the bolt 1 and the nut 2, and the fastened member. The automatic tightening means includes: a wedge member 6 having an inclined surface inclined circumferentially and slidably mounted on the fastened member; a support member 5 supporting one end side of the bolt 1 and the nut 2 and having a circumferentially inclined contact portion capable of engaging with the inclined surface of the wedge member 6 so as to slide along the inclined surface; and a coil spring 8 which engages with the wedge member 6 and the support member 5 so as to always urge them circumferentially with the wedging action of the wedge member 6 proceeding.
YOSHIMURA NORIO
Koichi Kajisaki
Yuzo Ozaki
Toshihiko Taniguchi