Check-actuated control mechanisms – Including means to test validity of check – By testing material composition
Reexamination Certificate
1999-10-26
2001-12-04
Bartuska, F. J. (Department: 2167)
Check-actuated control mechanisms
Including means to test validity of check
By testing material composition
Reexamination Certificate
active
06325197
ABSTRACT:
DESCRIPTION
1. Technical Field
The present invention relates to a method of and apparatus for determining authenticity of coins by discriminating them, and more particularly to a method of and apparatus for determining authenticity of coins used in automatic vending machines, game machines, etc.
2. Background Art
Coin discrimination apparatus prevailing in recent years is an electronic type using induction coils. This type of coin discrimination apparatus generally utilizes the falling of coins due to their own weight and is provided with a passage for guiding a coin inserted from a coin slot. A plurality of sets of induction coils are arranged along the passage to produce electromagnetic fields excited by respective different frequencies.
Inspection of coins is performed by detecting an amount of electrical change (change in frequency, voltage or phase) derived due to the interaction between the electromagnetic field and a coin when the coin passes through the electromagnetic field, to thereby inspect the authenticity of the coin.
Since in many cases features of coins appear in relation to frequency-dependent parameters, conventional coin inspection apparatus employs techniques of inspecting materials, outside diameters, thicknesses, etc. of coins by means of a plurality of frequencies, as disclosed in U.S. Pat. No. 3,870,137.
In recent so-called borderless societies in which coins can be easily brought from one country to another, an increasing number of such unacceptable coins tend to be used erroneously or deceitfully. Some of the coins used in various countries resemble each other in material, outside diameter, thickness, etc., and a typical example is 5-cent coin used in the U.S.A. and 5-centesimo coin used in Panama. Such coins differ from each other only in surface design (surface irregularity pattern) and are substantially identical with each other in material, outside diameter and thickness. With the conventional arrangement using induction coils, however, the surface irregularity patterns of coins show too subtle a change to be detected by simply using a plurality of frequencies, with the result that resembling coins like those mentioned above cannot be discriminated from each other.
Also, a 500-yen coin used in Japan and a 500-won coin used in South Korea are almost identical with each other in material and outside diameter, and differ from each other in that a 500-won coin has a slightly greater thickness. Thus, if a 500-won coin is machined and is used as a 500-yen coin, it is difficult to discriminate the two from each other with the conventional method in which the thickness, outside diameter and material of coins are inspected to determine the authenticity thereof.
Attempts have also conventionally been made to adopt an optical process such as image processing as a means of discriminating resembling coins like those mentioned above. However, optical apparatus has a problem that the authenticity determination of coins can be adversely affected by adhesion of dust or the like, and is also large in size and expensive because of its complicated structure.
DISCLOSURE OF INVENTION
The object of the present invention is to provide a method and apparatus for determining authenticity of coins whereby coins can be discriminated from each other with high accuracy.
A coin authenticity determining method of the present invention comprises the steps of: arranging an exciting coil and a receiving coil in the vity of a coin passage so that the exciting coil and the receiving coil are electromagnetically connected with each other, exciting the exciting coil to produce an electromagnetic field with such a frequency Iat an influence of a demagnetizing or reactive magnetic field caused by eddy current induced on a surface of the coin when the coin passes the electromagnetic field is detected by the receiving coil, and detecting the electomagnetic field influenced by the demagnetizing or reactive magnetic field as an electromotive force signal by the receiving coil; and discriminating the coin based on the electromotive force signal detected by the receiving coil.
The surface of the coin passing through the coin passage and the receiving coil should preferably be close to each other, and therefore the coin passage is formed such that the coin is inclined to one side of the coin passage where the exciting coil and the receiving coil are arranged. Also, the degree of penetration of electromagnetic field into a coin varies depending on the material of the coin and excitation frequency. Thus, an excitation frequency with which a difference in surface irregularity pattern of coins appears well as a difference of the signal from the receiving coil varies depending on the material of coins to be discriminated. Accordingly, the frequency at which the exciting coil is to be excited is selected in accordance with material of coins to be discriminated.
Specifically, authenticity of coins is determined by using an exciting coil arranged in the vicinity of one side of a coin passage inclining at a predetermined angle so that magnetic poles of the exciting coil faces the coin passage, two receiving coils having substantially identical characteristics and arranged in the vicinity of the coin passage so that the receiving coils are electromagnetically connected with the exciting coil, exciting means for exciting the exciting coil at a predetermined frequency to produce an electromagnetic field, bridge circuit means including the receiving coils, differential amplifier means connected to the bridge circuit means, detector means connected to the differential amplifier means, and determining means connected to the detector means, for comparing a signal obtained when a coin passes the electromagnetic field with a feature of a predetermined denomination stored in advance and determining that the coin is authentic if the signal is within a predetermined allowable range with respect to the feature.
REFERENCES:
patent: 3373856 (1968-03-01), Kusters et al.
patent: 3870137 (1975-03-01), Fougere
patent: 5458225 (1995-10-01), Iwamoto et al.
patent: S61-80491 A (1986-04-01), None
patent: H5-89319 A (1993-04-01), None
patent: H6-124380 A (1994-05-01), None
patent: H8-44926 A (1996-02-01), None
patent: H8-212416 A (1996-08-01), None
Bartuska F. J.
Kabushiki Kaisha Nippon Conlux
Koda & Androlia
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