| 摘要 |
PURPOSE: To achieve the sure and stable screwing while keeping the advantage of shorter peripheral length of a threaded streak by suppressing the screwing of a screw body whose peripheral length of the threaded streak is less than one periphery to such a degree as that no deviation is present or the generated deviation does not cause any practical failures. CONSTITUTION: A deviation preventing bar 5 is provided on one of unthreaded peripheral surface parts 6 of a screw body provided with a threaded bar 1 whose length is less than one periphery in the constitution where the threaded streak 1 does not cause any failures to the screwing with other threaded streak 7 of the screw body, and the generation of the deviation of the screw fitting to the other fitting of the screw body is prevented by the other striking of the screw body to this deviation preventing streak 5, so as to obtain the appropriate screw fitting condition. |
