| 摘要 |
PURPOSE:To secure pushing force in case when a magnetic medium is attached and to transfer exactly rotating force from a rotation driving pulley by engaging a collet with a collet center shaft through a bearing so that it can be moved up and down and can execute a rotating motion, and sticking a rigid plate to the upper part of the collet. CONSTITUTION:When a collet 3 moves downward, and an inside face 5-1 of a magnetic medium 5 contacts with a collet attaching pawl 301, a core shift of the magnetic medium 5 is brought almost to the center of a rotation driving pulley 6, and the medium 5 is pinch-held by an upper face 6-1 of the pulley 6 and a lower projecting part 3-2 of the collet 3. When pushing force is further applied, the collet attaching pawl 3-1 is spread by an elastic deformation of the collet 3, and the medium inside face 5-1 is pushed uniformly extending over the whole circumference, aligned with the center of the pulley without eccentricity and made to press-contact. As for vertical pushing force in the lower direction, which is required for the elastic deformation of the collet 3 in this case, small force will do, and even if the magnetic medium 5 is eccentric against the center of the pulley 6, when the collet 3 is spread until it is aligned with the pulley 6, only frictional force is generated, therefore, the magnetic medium 5 can be attached by scarcely having eccentricity to the center of the pulley. |
