| 摘要 |
PURPOSE:To prevent the invasion of dust, etc. to a magnetic head shift mechanism by detecting the reference position of a magnetic head by means of an interrupter which is revolved in a body with a rotary shaft of a motor for drive of the head shift mechanism. CONSTITUTION:A stepping motor 11 is revolved toward an arrow head, and a shift mechanism 5 is moved toward an arrow head via a steel belt 13 wound and fixed around a pulley 12. In this case, an interrupter 20 is revolved together with a damper main body 18 by a rotary shaft 11A of the motor 11. Then the interrupter 20 is put into a gap 30 of a photoelectric sensor 27 to cut the light given to a photodetecting element 29 from a light emitting element 28. Thus it is detected that a magnetic head 4 is set accurately on a reference track of a disk 3. A reference position detector is provided at the outside of a housing and therefore can be maintained and repaired without opening a cover of the housing. This prevents the invasion of dust, etc. into the housing. |
