PURPOSE: To facilitate the installation work of a seat metal having a cut part and improve reliability in preventing slipping-off by installing a seat metal, having a cut part made of shape memory alloy, on the neck part of a necked screw.
CONSTITUTION: A seat metal having a cut part is made of shape memory alloy, and the inside diameter (d) is larger thant the outside diameter of the neck part 12 of a necked screw 10, and the outside diameter D has a ring plate shape which is sufficiently larger than the diameter of a screw hole 6 on a cover 5, and the ring part has a cut part 21. When the seat metal 20 is heated over a transformation temperature, one ring part to the cut part 21 is bendingly deformed in the vertical direction from a memory line 22 part, and shape memorized so as to be bent 25. Accordingly, the seat metal 20 having a cut part restores the shape, and when the bending 25 is generated, an opened port 26 communicating to the hole part is formed on the cut part 21. Accordingly, the installation work of the seat metal 20 having the cut part is facilitated, and the trouble with slipping-off is eliminated, and the reliability in preventing slipping-off is improved.
KAWANAMI YASUSATO
SAKAI SHIGERU
SHINOHARA KENJI
