| 摘要 |
PURPOSE:To eliminate the load variance at the driving of a mobile stage and to improve the reliability for the driving by moving the mobile stage while winding up the middle part of a wire by means of a driving pulley. CONSTITUTION:A wire 18 is extended between fixing tools 17 on a base plate 1 in parallel to a rail 2 and along the moving direction of mobile stage 3. Then the middle part of the wire 18 is wound round a driving pulley 6. When the pulley 6 is revolved by a motor 8, the pulley 6 moves together with the stage 3 while winding up the middle part of the wire 18. At the same time, the motor 8 is controlled to the base of a tone arm 4. An arm servo sensor device 19 consists of a slit plate 20 provided to the arm 4 and a photosensor 21 which detects the revolution of the arm 4 in response to the movement of the plate 20. |
