| 摘要 |
PROBLEM TO BE SOLVED: To obtain a screw part to exert secure locking effect with simple structure at low cost. SOLUTION: In the screw part 1 comprising a screw head 2 and a foot 4 having a screw thread 3, a non thread part 10 sliding with an inside diameter of the internal screw 21 is formed on a leading end of the foot 4 having the screw thread 3 capable of screwing to an inside diameter of an internal thread 21 has the locking effect in which the non thread part 10 is of polygonal shape of triangle to hexagonal, therefore not only the locking effect is reduced in variation but also the screw part is resolved from screwing into with running off the thread. Since the inside of the internal thread is prescribed, the locking action is stable and reliability thereof is improved. Even when the screw part is made of austenitic stainless steel, a contraction percentage of the material is low at forging, thereafter the material can be sufficiently used for screw part so as to widen a range of usage for locking screw part.
|
