Process for stopping a rotating disc-shaped record medium
US5448549A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 3, 1992 |
| Grant date | Sep 5, 1995 |
| Priority date | — |
| Expiry date | Dec 3, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P3/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Process for stopping a record-shaped, rotating information medium, for example, a CD. CD-players, for example, are provided with a loading and unloading mechanism for the information medium, the CD. However, before a CD can be automatically unloaded by the CD-player after reproduction or activation of a STOP-key, the rotation of the CD must be stopped in order to avoid damages of its sensitive surface. Because the moment of inertia and the diameter of records (CDs) are varied, and because a small mini-CD exists, it may occur that the CD is still rotating during the unloading process. To stop the record (CD) safely independently of its moment of inertia and its size, a first applied braking pulse (B1) causes the record (CD) to be braked to full stop and subsequently to be accelerated in the opposite direction. In the course of this braking and acceleration, the time T, which passes until the rotational speed of the record (CD) has reversed due to the first braking pulse (B1) from a preset value +N to a value -N, is measured. Moreover, when the rotational speed has reached the value -N, the polarity of the first braking pulse (B1) is reversed and a second braking pulse (B2) is applie…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.