Coin selection method and apparatus
First Claim
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1. Apparatus for examining conductive coins with respect to authenticity and denomination comprising
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Abstract
A method and apparatus for use in identification of coins is disclosed in which a coin is passed through the electromagnetic field of an inductor in an oscillator circuit and the changes in both the frequency and amplitude of oscillation of said oscillator circuit are separately detected.
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7 Claims
- 1. Apparatus for examining conductive coins with respect to authenticity and denomination comprising
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2. an oscillator circuit including an inductor arranged to subject a face of a coin to an electromagnetic field, wherein the presence of the coin or other conductive object within the field affects the frequency of the oscillator,
first means for producing a first alternating current signal representative of the output of the oscillator with respect to the effect of the presence of a coin within the field upon the amplitude of oscillations of the oscillator, said first means comprising a first detecting circuit having a time constant greater than one machine cycle to produce a reference signal, a second detecting circuit having a time constant greater than one period of oscillation of the lowest oscillator frequency and substantially less than 20 milliseconds, and a comparator to compare the output of the first detecting circuit with the output of the second detecting circuit, second means for producing a second signal representative of the output of the oscillator with respect to the effect of the presence of a coin within the field upon the oscillator frequency, means for comparing a value of each of the first and second signals respectively to correspondng values representative of an acceptable coin and indicating the presence of an acceptable coin, and combinatorial means to produce a third signal when the comparing means indicate the presence in the field of an acceptable coin of the same denomination as indicated by the first and second signals.
Specification