| 摘要 |
PURPOSE:To simplify the assembling process of a record size detecting mechanism with use of an inexpensive material for reduction of cost, by providing plural detection pins projected over a turntable for discrimination of record sizes. CONSTITUTION:The 1st and 2nd detectors 2 and 3 are provided on a turntable 1 at positions distant from the center of the table 1 at the prescribed angles respectively. When a record disk 10 is put on the table 1, a detection pin 15 of the detector is pushed down. Then a ferromagnetic material bar 17 attached at the lower end of the pin 15 is moved down to a level approximately equal to the level of an air core coil 18. When the table 1 is revolved, the bar 17 comes close to the place just beside the coil 18 for each revolution. Thus the inductance of the coil 18 changes. At least 2 detectors having the same structure as the detector 3 are prepared for detection of the inductance change of the coil 18. Thus the record sizes are decided.
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