Electrically controlled radial mass shifting elements for turntable speed regulation in an apparatus for reading disc-shaped information carriers
US3947625A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 1974 |
| Grant date | Mar 30, 1976 |
| Priority date | — |
| Expiry date | Nov 14, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7605
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for reading disc-shaped information carriers which are provided with substantially circular tracks, in which information is stored in coded form, in particular picture information, which information carriers are disposed on a turntable, a read unit supplying a control signal to a control device for maintaining the reading speed constant. The control device comprises at least two mass elements which are connected to the turntable symmetrically relative to the axis of rotation of the turntable, resiliently in the radial direction and rigidly in the tangential direction, which elements are radially movable in response to the control signal. In one control device each element consists of an axially magnetized rod-shaped permanent magnet, which is attached to the turntable by at least one radially flexible leaf spring, a coil being disposed around each magnet, which coil is connected to the control signal. In another control device each element is identically attached to the edge of a metal disc via a connecting rod, which disc is disposed centrally and loosely around the drive shaft of the turntable, at least one electro-magnet being disposed underneath the disc, which ele…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.