Coin detection and validation means
US5293979A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 10, 1991 |
| Grant date | Mar 15, 1994 |
| Priority date | — |
| Expiry date | Dec 10, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D5/08
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
Apparatus for more accurately distinguishing between metal objects including coins based on the affect of the object or coin on the electrical characteristics of a pair of tank circuits when the tank circuits are subjected to a charging pulse which ends at a time when the object or coin is in the field thereof. The tank circuits can be connected into different configurations with the fields of their respective coils positioned to be subjected to the object or coin to be distinguished. The tank circuits can have similar or different characteristics and the coils of the tank circuits can be arranged in an aiding or in an opposing relationship. The present apparatus may also include apparatus to provide automatic tuning and self adjustment using a comparison between a portion of a signal produced by ringing one or more tank circuits and a fixed reference voltage level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.