To provide a screw that sufficiently utilizes a fastening force developed by a washer by releasing to action a suppressed repulsive force between a screwhead and the washer after screw tightening to increase a pressing force developed against the fastened member after tightening into a tapped hole.
The screw 4 includes the washer 143 passed about a threaded shaft 142 and placed into surface contact with the perimeter of a tapped hole when the screw is tightened into a member 220 to be fastened, a repulsive force generation means 144 for developing a repulsive force of widening a gap between the screwhead 141 and the washer 143 to increase a pressing force of the washer 143 to the member 220 to be fastened, and a repulsive force suppression means 145 configured to fix a bearing surface 141a of the screwhead 141 and a facing end face of the washer 143 at a predetermined gap by applying a coupling force in advance against the repulsive force of the repulsive force generation means 144 to compress the repulsive force generation means 144, and to release the repulsive force of the repulsive force generation means 144 by canceling the coupling force application after tightening into the tapped hole.
HIRAHARA TATSUYA
| JPH08128432A | 1996-05-21 | |||
| JPH08200344A | 1996-08-06 | |||
| JPS441092B1 |
Yasuhiko Murayama
Hiroshi Watanabe
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