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US 5,244,070 AGranted
Dual coil coin sensing apparatus
AssigneeDuncan Industries Parking Control Systems Corp.
InventorsRalph H. Carmen, James M. Rodgers
Life of this patent
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Abstract
An apparatus for sensing coins is disclosed which is capable of distinguishing between valid and non-valid coins as well as between the different denominations of coins. The apparatus is useful for application in coin-operated parking meters as well as other coin-operated machines. The apparatus makes use of a twin-coil sensor which enables it to distinguish between small coins with high metal content and large coins with low metal content.
Claims30
A coin sensing apparatus, comprising:
- a pair of sensor coils electrically connected in series and physically arranged so that a coin deposited into the apparatus may pass sequentially through each sensor coil and thereby change the impedance of the coil;
- a sensor oscillator circuit incorporating the pair of sensor coils which outputs an oscillating sensor signal at a frequency dependent on the impedance of the sensor coils;
- and,
- counter means for measuring the frequency of the sensor signal as a coin passes sequentially through the sensor coils to obtain a frequency signature for the coin which can be compared with characteristic frequency signatures of valid coins.
1 more element
Dependencies are inferred from the claim text.