| 摘要 |
PROBLEM TO BE SOLVED: To make a shape of a screw part that is detachably connected to a screwing part without an adapter, even when different kinds of screws are used. SOLUTION: Two connection parts are detachably connected to each other by screwing. Shapes of threads are formed on a male screw or a female screw at one of the connection part, using a common part which is formed when at least two or more kinds of screws are jointed. Furthermore, the surface at one part of the shapes of the threads is formed approximately flat, with the smallest screw bottom diameter among various screw bottom diameters of respective kinds of screws, to be threaded. |
