| 摘要 |
PURPOSE:To ensure the turning of the cassette case with the disk stored at the reproduction time by providing the ribs to the upper and lower plates of the cassette case and thus preventing the dust from entering the cassette case through the rotary hole provided to the cassette case at the non-reproduction time. CONSTITUTION:Cassette case 10 consists of upper and lower plates 11 and 12 plus others, and disk 1 is stored into space 13 between plates 11 and 12. Rib 15 among ribs 14 and 15 provided to plates 11 and 12 is formed so as to touch the central non-record surface of disk 1, and thus no dust enters space 13 through rotary holes 16 formed to plates 11 and 12. When cassette disk 1 is reproduced, enter axle 31 is fitted to center hole 3 for disk 1. Thus disk 1 is pressed by holder axle 32 to be fixed to turntable 30. At the same time, case 10 is fixed to substrate 40 to be given the electric conduction to electromagnet 41. As a result, steel plate 17 of plate 12 is stretched to secure a minute space to rib 15 from disk 1. |
