| 摘要 |
PROBLEM TO BE SOLVED: To provide a nut which can be retightened even in the case where the nut cannot be rotated integrally with a member to be fastened while the nut is fixed to the member to be fastened.SOLUTION: This invention comprises a casing having a cylindrical inner space and a screw member inserted into the casing. The screw member is a substantial cylindrical member having a tapered hole, a diameter of which is expanded rearward. A tapered surface of the tapered hole is provided with a plurality of guide walls properly spaced apart from each other and arranged in a circumferential manner. Each of divided threads is movably arranged between the adjoining guide walls in an axial direction of the tapered surfaces to form a female thread part corresponding to a male thread. Biasing means for always biasing the divided thread forward is provided in the screw member and there is provided rotary means for rotating the screw member. |
