EP0062411A2
Expired / Lapsed
EP
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Method and apparatus for coin validation
Assignee: Landis and Gyr Communications UK Ltd
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Filing: 1982-03-08
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Granted: —
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Expires: 2002-03-08
Abstract
Abstract Coin validation apparatus may be associated with a coin freed mechanism on coin receiving machines or form part of a coin sorting apparatus to check that coins are valid coins and not counterfeit. Recently, it has become particularly convenient to use the interaction between a coin and an alternating magnetic field to gauge various parameters of the coin thereby to determine if the coin is valid. In such a method the frequency of a feedback oscillator having a tuned electrical coil in its feedback loop is monitored when a coin is present adjacent the coil, the frequency is then monitored when a phase shift or time delay network is also included in its feedback loop, two parameter signals characteristic of the effect of the coin on both the inductance and the loss factor of the coil, are derived from these maintained frequencies and the two parameter signals are compared with reference values to determine if the coin is valid.
Inventors
- 👤 George Reginald Howard
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 17:50
CPC Classifications
G; G07; G07D; G07D5/00; G07D5/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
95 words
A method of validating a coin comprising monitoring the frequency of a feedback oscillator having a tuned electrical coil in its feedback loop when a coin is present adjacent the coil, monitoring the frequency of the feedback oscillator when a phase shift or time delay network is also included in its feedback loop, deriving from the monitored frequencies two parameter signals characteristic of the effect of the coin on both the inductance and the loss factor of the coil, and comparing the two parameter signals' with reference values to determine if the coin is valid.
Claim 2
Independent Claim
95 words
A method of validating a coin comprising monitoring the frequency of a feedback oscillator having a tuned electrical coil in its feedback loop when a coin is present adjacent the coil, monitoring the frequency of the feedback oscillator when a phase shift or time delay network is also included in its feedback loop, deriving from the monitored frequencies two parameter signals characteristic of the effect of the coin on both the inductance and the loss factor of the coil, and comparing the two parameter signals' with reference values to determine if the coin is valid.
Claim 3
Dependent Claim
181 words
A coin validation apparatus comprising an electrical coil (1), means to hold a coin at a fixed reference position adjacent the electrical coil (1), a feedback oscillator (TR2, TR3) having the electrical coil (1) in its feedback loop and also having a phase shift or time delay network (5, 6, 7) switchable into and out of.its feedback loop,.frequency monitoring means (11 or 15) for monitoring the frequency of the feedback oscillator and for producing an output signal indicative of its frequency, means (11 or 16 to 22) responsive to the output signal of the frequency monitoring means both when the phase shift or time delay network (5, 6, 7) is switched into and out of the feedback loop for producing the two parameter signals characteristic of the effect of the coin on both the inductance and loss factor of the coil (1) and means (11 or 23 to 34) to compare the two parameter signals with reference values to determine if the coin is valid and to output a coin validation signal when both parameter signals correspond to the reference values.
Claim 4
Dependent Claim
181 words
A coin validation apparatus comprising an electrical coil (1), means to hold a coin at a fixed reference position adjacent the electrical coil (1), a feedback oscillator (TR2, TR3) having the electrical coil (1) in its feedback loop and also having a phase shift or time delay network (5, 6, 7) switchable into and out of.its feedback loop,.frequency monitoring means (11 or 15) for monitoring the frequency of the feedback oscillator and for producing an output signal indicative of its frequency, means (11 or 16 to 22) responsive to the output signal of the frequency monitoring means both when the phase shift or time delay network (5, 6, 7) is switched into and out of the feedback loop for producing the two parameter signals characteristic of the effect of the coin on both the inductance and loss factor of the coil (1) and means (11 or 23 to 34) to compare the two parameter signals with reference values to determine if the coin is valid and to output a coin validation signal when both parameter signals correspond to the reference values.
Claim 5
Dependent Claim
139 words
A coin validation apparatus according to claim 2, in which the frequency monitoring means, the means responsive to the output signal of the frequency monitoring means for producing the two parameter signals and the means to compare the two parameter signals with reference values comprise a programmed microprocessor (11) which is programmed to compare the output signal produced when the phase shift or time delay network (5, 6, 7) is switched into the feedback loop of the feedback oscillator (TR2, TR3) with the output signal produced when the phase shift or time delay network (5,6,7) is switched out of the feedback loop to produce a first parameter signal and to produce a second parameter signal dependent upon the output signal produced when the phase shift or time delay network (5, 6, 7) is switched out of the feedback loop.
Claim 6
Dependent Claim
55 words
A coin validation apparatus according to claim 3, in which the second parameter sie.al is the output signal produced when the phase shift or ime delay network (5, 6, 7) is switched o L of the feedback loop or this output signal operated on by a fêxed operator such as a constant division or subtraction,
Claim 7
Dependent Claim
177 words
A coin validation apparatus according to claim 2, in which the means responsive to the output signal of the frequency monitoring means for producing the two parameter signals comprises first storage means (19) for storing the output signal produced when the time delay or phase shift network (5, 6, 7) is switched out of the feedback loop, first comparison means (17) for comparing the output signals produced when the phase shift or time delay network (5, 6, 7) is switched into the feedback loop with that produced when the phase shift or time delay network (5, 6, 7) is switched out of the feedback loop to produce a first parameter signal, second storage means (14) for storing at least two reference values, and second comparison means (23 to 34) to compare the first parameter signal and the.content of the first storage means (19) which forms the second parameter signal with the reference values stored in the second storage means (14) to produce a coin validation signal when both coin parameter signals correspond to the stored reference values.
Claim 8
Dependent Claim
23 words
A coin validation apparatus according to claim 5, which is implemented either by a dedicated microprocessor or by a hard wired logic circuit.
Claim 9
Dependent Claim
44 words
A coin validation apparatus according to any one of claims 2 to 6, in which the phase shift or time delay network does not have a constant characteristic, but instead, results in a phase shift that varies with the resonant frequency of the oscillation.
Claim 10
Dependent Claim
122 words
A coin validation apparatus according to any one of claims 2 to 7, in which the phase shift network includes an operational amplifier (5) having a parallel connected capacitive (7) and resistive (6) feedback network and an input resistor (8) connected between the inverting input of the operational amplifier (5) and ground. 9: A coin validation apparatus according to claim 8, in which a solid state switch (TR4) is provided in parallel with the resistive capacitive feedback network (6, 7) of the operational amplifier (5) to short out the parallel capacitive and resistive feedback network (6. 7) of the operational amplifier (5) when the phase shift network is to be switched out of the feedback loop of the feedback oscillator (TR2, TR3).
Claim 11
Dependent Claim
45 words
A coin validation apparatus according to any one of claims 2 to 9, in which the coil (1) is formed in two parts connected in series with the fixed reference position of the coin being located in between the two parts of the coil (1).
Claim 12
Dependent Claim
42 words
A coin validation apparatus according to any one of claims 2 to 10, in which the frequency monitoring means includes a counter (15) arranged to count the number of the oscillations of the feedback oscillator that occur within a preset time interval.
References Cited (Backward Citations)
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