JP2920798B2 - Coin discriminator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in public telephones, vending machines, etc., and determines the authenticity, type, etc. of a coin by judging the thickness or material of the coin by a transmitting / receiving coil arranged in a coin orbit. The present invention relates to a determination device.

[0002]

2. Description of the Related Art A conventional coin discriminating apparatus using a magnetic field in a public telephone, a vending machine, and the like is disclosed in Japanese Patent Application No. 57-1.
As in 73099 (the basic configuration is shown in FIG. 20), there is a method of judging the thickness or the material by comparing the signal of the coin detector with the signal of the standard detector.

That is, in this prior art, the test coin C1
And the standard sample coin C2 are arranged in the alternating magnetic field generated by the transmitting coils 1 and 2 driven by the same driving device, and the detectors 3 and 4 detect the magnetic fields generated by the coins C1 and C2, respectively. The thickness or material of the test coin C1 was determined by comparing the output signal of the detector 3 for the test coin C1 with the output signal of the detector 4 for the standard sample coin C2.

[0004]

However, in the conventional coin discriminating apparatus having such a configuration, in addition to the transmission coil 1 and the detector 3 for the test coin C1, the transmission for the standard sample coin C2 is performed. Since the coil 2 and the detector 4 are required, there is a problem that the apparatus becomes complicated, and without the standard detector 4, the detection signal level is unstable with respect to drift due to disturbance.

An object of the present invention is to provide a high-precision coin discriminating apparatus which solves such problems.

[0006]

In order to achieve the above object, a coin discriminating apparatus according to a first aspect of the present invention applies an alternating magnetic field to a coin which is arranged near a coin orbit and moves along the coin orbit. A transmitting coil and a discrimination target arranged near the coin orbit and at a position receiving the magnetic field of the transmitting coil, so that an eddy current distribution in the coin that changes according to the thickness or material of the coin can be detected. A receiving coil formed to be smaller in diameter than a coin and detecting the eddy current distribution as a change in induced voltage; a signal extracting means for extracting a signal induced in the receiving coil; and a peak of a signal extracted by the signal extracting means The system includes a peak number detecting means for detecting the number, and a judging means for judging the thickness or the material of the coin from the peak number.

According to a second aspect of the present invention, there is provided a coin sorting apparatus comprising: a transmitting coil disposed near a coin orbit to apply an alternating magnetic field to coins moving along the coin orbit; The coin is formed at a smaller diameter than the coin to be discriminated so as to be able to detect the eddy current distribution in the coin that changes according to the thickness or the material of the coin, and the distribution of the eddy current is changed by the induced voltage. A receiving coil, a signal extracting unit for extracting a signal induced in the receiving coil, a peak width detecting unit for detecting a width of two peaks of the signal extracted by the signal extracting unit, and the peak width. And a judging means for judging the thickness or material of the coin from the coin.

[0008]

According to the first aspect of the present invention, an eddy current is generated in a coin moving along a coin orbit by an alternating magnetic field generated from the transmitting coil. The magnetic field generated by the eddy current causes a change in the induced voltage in the receiving coil when the coin passes through the receiving coil. This eddy current is generated on the center side of the coin as the thickness of the coin is smaller and the conductivity of the coin is smaller, and is generated on the outer peripheral side of the coin as the thickness of the coin is larger and the conductivity of the coin is larger. . For this reason, the output waveform of the induced voltage change of the receiving coil has a single peak with one peak or a double peak with two peaks due to slight differences in the thickness and conductivity of the coin to be inspected. Or Therefore, the number of peaks of the output waveform of the receiving coil is detected, the thickness and the material of the coin are determined, and the authenticity and type of the coin are determined.

In the second invention, even when the output waveform of the receiving coil is a bimodal type, the distance between the two peaks changes due to the difference in the thickness and conductivity of the coin to be inspected. For this reason, the distance between the peaks of the output waveform of the receiving coil is detected, the thickness and material of the coin are determined, and the authenticity and type of the coin are determined.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic principle of coin discrimination by the coin discriminating apparatus of the present invention will be described.

As shown in FIG. 1, a coin C moves while rolling and falling on a coin orbit 10 by its own weight. In the vicinity of the coin orbit 10, a transmitting coil 11 and a receiving coil 12 are provided, for example, in an arrangement as shown in FIG. Transmission coil 1
When an AC signal is applied to the transmission coil 11
Arising from When the coin C passes through this alternating magnetic field, an eddy current flows in the coin C in the circumferential direction as shown in FIG.
An alternating magnetic field is generated by the eddy current.

An alternating magnetic field generated by the transmitting coil 11 and an alternating magnetic field generated by the eddy current interlink in the receiving coil 12 disposed near the transmitting coil 11, and an electromotive force is generated by these two alternating magnetic fields. When the electromotive force due to the eddy current is selectively extracted from the electromotive force induced in the receiving coil 12,
Since the electromotive force due to the eddy current changes due to the movement of the coin C, a voltage waveform having one or two peaks is detected as described later. The inventors quantitatively obtained this voltage waveform by numerical calculation using the finite element method.

FIGS. 3 to 5 show examples of numerical calculations using the finite element method. 3A to 5A show the positional relationship between the transmission coil 11 and the coin C, and FIG. 3B shows the distribution of the eddy current flowing through the coin C at that position.

FIG. 3B shows an eddy current flowing in the coin C when the distance between the transmitting coil 11 and the center of the detected coin C is 50 mm. It can be seen that the eddy current rotates clockwise and flows strongly near the transmission coil. FIG. 4B shows the transmission coil 11 and the coin C to be detected.
Shows the flow of the eddy current when the distance between the centers is 25 mm. It can be seen that there are two eddy current flows in the coin C. FIG. 5B shows the flow of the eddy current when the center of the coin C to be detected matches the center of the coin C to be detected. The flow of the eddy current turns counterclockwise, contrary to the case of FIG. By performing such numerical calculations with the center-to-center distance being slightly changed, the distribution of the eddy current, the magnetic field distribution generated by the eddy current, and the electromotive force waveform induced by the magnetic field were systematically grasped. Furthermore, by performing this method by changing the conductivity and thickness of the coin, (a) when the conductivity is small or the thickness is small, an eddy current due to an alternating magnetic field flows near the center of the coin, and (b) ) When the conductivity was large or the thickness was large, it was quantitatively grasped by numerical calculation that the eddy current due to the alternating magnetic field flows around the outer periphery of the coin.

The analysis results obtained by such numerical calculations are shown below.

FIGS. 6 and 7 show that the center of the receiving coil 12 is 12.5 mm from the coin orbit 10 as shown in FIG.
This is a magnetic flux density distribution when a coin C having a diameter of 16.0 mm moves on the coin orbit 10. 6 and 7, the horizontal axis represents the distance between the coin C and the center of the receiving coil 12, and the vertical axis represents the magnetic flux density received by the receiving coil 12. Accordingly, the horizontal axis represents the case where the coin C moves rightward after passing through the center of the receiving coil 12 since the center of the receiving coil 12 is set to 0.

FIG. 6 shows waveforms when coins have the same diameter and thickness (diameter 16.0 mm, thickness 2.0 mm) and only the conductivity is changed. When the right half and the left half of a coin are considered together from the slope of the horizontal axis near 0, the conductivity is 1.64 × 10
^{At 7} [S / m] and 2.5 × 10 ⁷ [S / m], it becomes a single peak, 3.82 × 10 ⁷ [S / m] and 5.92 × 10 ⁷
At [S / m], it can be seen that the peak is bimodal. At the time of a single peak,
The conductivity is smaller than 3.82 × 10 ⁷ [S / m]. In the case of the double peak, the conductivity is larger than 2.5 × 10 ⁷ [S / m].

FIG. 7 shows that the diameter and conductivity are the same (diameter 1
The waveform when the thickness is changed only at 6.0 mm and the conductivity is 2.5 × 10 ⁷ S / m) is shown. When considering the right and left halves of a coin together, from the slope of the waveform near 0,
1.2 [mm], 2.0 [mm], 2.8 [m]
m], the peak is unimodal, and at 4.0 mm, the peak is bimodal. In the case of a single peak, the thickness is greater than 4.0 [mm]. In the case of a double peak, the thickness is greater than 2.8 [mm].

Such a single peak or a double peak is caused by (a) when the conductivity is small or the thickness is small, an eddy current due to an alternating magnetic field flows near the center of the coin. (B) When the conductivity is large or the thickness is large, the eddy current due to the AC magnetic field flows around the outer periphery of the coin. It is considered that the position of the eddy current changes depending on the thickness and the conductivity of the coin C.

Therefore, according to the results of FIGS. 6 and 7, whether the output waveform due to the eddy current of the receiving coil 12 is single-peak or double-peak,
Thus, it is possible to stably and accurately detect whether the conductivity or the thickness is larger or smaller than a certain threshold value. Therefore, to detect the difference in the thickness of the proximity to determine the face value of the genuine coin, or to reject only the counterfeit coins of specific metals that are easily available and close to the conductivity of the genuine coin,
It is very effective for such uses.

FIGS. 9 and 10 show the magnetic flux when the center of the receiving coil 12 is located at 15.0 mm from the coin orbit and the coin C having a diameter of 30.0 mm moves along the coin orbit 10 as shown in FIG. It is a density distribution. 9 and 10, the horizontal axis represents the distance between the coin C and the center of the receiving coil 12, and the vertical axis represents the magnetic flux density received by the receiving coil 12. Therefore, the horizontal axis shows the case where the coin C moves rightward after passing through the center of the receiving coil 12 because the center of the receiving coil 12 is set to 0.

FIG. 9 shows the same diameter and thickness (diameter 30.0
mm and a thickness of 1.8 mm), the waveform is shown when only the conductivity is changed. When the right half and the left half of a coin are considered, the detected waveform is bimodal regardless of the conductivity, and it can be seen that the distance between the peaks changes depending on the conductivity. The conductivity is 1.6 when the peak interval is 23.6 mm.
4 × 10 ⁷ [S / m], when the peak interval is 24.6 mm, 2.50 × 10 ⁷ [S / m], the peak interval is 24.8
mm is 2.82 × 10 ⁷ [S / m], and when the peak interval is 25.6 mm, it is 5.92 × 10 ⁷ [S / m].

FIG. 10 shows that the diameter and conductivity are the same (diameter 3
0.0 mm, conductivity 2.5 × 10 ⁷ S / m), and the waveform when only the thickness is changed is shown. When the right half and the left half of the coin are considered, the detected waveform is bimodal regardless of the thickness, and it can be seen that the distance between the peaks changes depending on the thickness. The thickness is 1.2 mm when the peak interval is 23.0 mm, and 1.6 when the peak interval is 23.8 mm.
mm, 2.0 mm when the peak interval is 24.2 mm, and 2.6 mm when the peak interval is 24.4 mm.

The peak interval of the bimodal waveform changes as described above because (a) when the conductivity is small or the thickness is thin, an eddy current due to an alternating magnetic field flows near the center of the coin, and ) When the conductivity is large or the thickness is large,
Based on the principle that the eddy current due to the AC magnetic field flows around the outer periphery of the coin, the position of the eddy current in the coin C when the coin C passes through the receiving coil 12 as shown in FIG. It is thought that it is.

Therefore, the thickness or conductivity of the coin can be quantitatively determined from the peak interval of the bimodal waveform.

An embodiment of the coin discriminating apparatus of the present invention based on the above-described coin discriminating principle will be described below.

As shown in FIGS. 12 to 14, the coin orbit 10 includes a substrate 13 provided at an angle with respect to the vertical plane, a parallel cover plate 14 spaced apart from the substrate 13, and
A rail 15 is attached to the cover plate 14 and is inclined with respect to a horizontal line. The coin C that has fallen into the coin orbit 10 comes into contact with the rail 15 at the peripheral end face C ′,
While the abdominal surface C ″ is in contact with the substrate 13, it rolls and falls along the inclined rail 15.

The transmitting coil 11 is provided on the substrate 13 in a plane substantially parallel to the substrate 13, and the receiving coil 12 smaller than the transmitting coil 11 is provided inside the transmitting coil 11.

As shown in FIG. 14, the transmission coil 11 is wound around a bobbin, and this bobbin is fitted inside a large core 18 having a bottomed cylindrical shape. Receiving coil 12
Is wound on a bobbin, and this bobbin is
In the annular groove 19a. Then, the large-diameter core 18 is fitted into the round hole 13a of the
3 is fixed so as to be flush with the surface. 20
Is a ring-shaped spacer or a part of the large-diameter core 18.

As shown in FIG. 13, the size (inner diameter) of the receiving coil 12 needs to be considerably smaller than the diameter of the coin C, and is preferably not more than 0.25 times the diameter of the coin.

The transmitting coil 11 needs to be considerably larger than the receiving coil 12, and its size (inner diameter) is desirably 0.5 times or more the diameter of the coin C.

FIG. 15 is a block diagram showing an embodiment of an electric circuit of the coin discriminating apparatus.

In FIG. 15, a capacitor 21 is connected to the transmission coil 11 to form a resonance circuit, and a capacitor 22 is connected to the reception coil 12 to form a resonance circuit.
A relatively low frequency output ((a) of FIG. 16) of an oscillator 24 connected in series with a resistor 23 is applied to the transmission coil 11 to generate an alternating magnetic field. An electromotive force is generated in the receiving coil 12 by this alternating magnetic field. When the coin C passes through the receiving coil 12, an eddy current is generated in the coin C by an alternating magnetic field, and an electromotive force is generated in the receiving coil 12 also by the magnetic field due to the eddy current. Therefore, the receiving coil 12
Generates an electric signal, and sends the signal ((b) in FIG. 16) amplified by the buffer amplifier 25 to the sample-and-hold circuit 26.

The sample hold circuit 26 is driven by a sample pulse ((c) in FIG. 16) whose phase is delayed by, for example, 90 ° from the drive signal of the transmission coil 11 generated by the sample pulse generation circuit 27. Is sampled as shown in FIG. 16 (d), converted into a voltage level and converted to a direct current.

An electromotive force generated in the receiving coil 12 when there is no coin, and a magnetic field of an eddy current in the coin, the receiving coil 1
2 has a phase difference of 90 ° with the electromotive force generated in the transmission coil 11, the sampling signal having a phase difference of 90 ° from the drive signal of the transmission coil 11 as described above,
The electromotive force of the receiving coil 17 due to the magnetic field of the eddy current in the coin is best extracted.

The output of the sample and hold circuit 26 is A /
The signal is A / D converted by the D converter 28 and sent to the waveform observation unit 31 of the CPU 30.

When the receiving coil 12 is arranged with respect to the coin C as shown in FIG. 8, as shown in FIGS. 6 and 7, depending on the difference in the conductivity and the thickness of the coin C to be determined, The output waveform due to the magnetic field of the receiving coil 12 has a single peak as shown in FIG. 17A, or has a double peak as shown in FIG. 17B (FIG. 17A shows FIG. 16A). (D) is drawn with the time axis of the waveform shortened.)

In the waveform observing section 31 of the CPU 30, the A / D
The peak of the signal is detected from the output of the converter 28, the number of peaks is counted, and the result is sent to the determination unit 32. The determination unit 32 compares the number of peaks with the coin determination data (the number of peaks) stored in the storage circuit 33 in advance to determine whether or not the coin is a true coin, or the type of the coin. The coins are sorted by the coin sorting device 34 in the storing direction, the discharging direction, and the like based on the determination signal.

As described above, when the receiving coil 12 is arranged with respect to the coin C as shown in FIG. 11, the eddy current of the coin is caused by the passage of the coin C as shown in FIGS. Is always bimodal, but the peak-to-peak distance of the bimodal output signal varies depending on the conductivity and thickness of the coin.

FIG. 18 shows an embodiment of the present invention in which the authenticity and the type of a coin are determined based on the distance between the peaks.

In FIG. 18, an alternating magnetic field is generated by applying the relatively low frequency output of the oscillator 24 to the transmitting coil 11, and the output signal of the receiving coil 12 is amplified by the buffer amplifier 25 as in the embodiment of FIG. The sample and hold circuit 26 samples with a sampling pulse delayed by 90 ° from the drive signal of the transmission coil of the sampling pulse generation circuit 27, extracts the output of the coin by the magnetic field of the eddy current, and converts it into a voltage level signal.

The coin C includes the transmitting coil 11 and the receiving coil 12
When passing through the eddy current, the eddy current flows in the coin C due to the alternating magnetic field generated by the transmitting coil 11, and the position where the eddy current flows varies depending on the conductivity and the thickness as described above (the conductivity is high and the thickness is high). The thicker, the more concentrated outside.)
Therefore, if the coin C and the receiving coil 12 have a size relationship as shown in FIG.
At a timing t1 when the coin C passes through the receiving coil 12 and at a timing t2 when the rear side of the coin C passes through the receiving coil 12, a double-peaked signal shown in FIG. Since the position where the eddy current flows depends on the conductivity and the thickness of the coin C, the timings of these two peaks t1 and t1
The time between the two depends on the conductivity or thickness of the coin.

The output signal of the sample hold circuit 26 is input to the differentiating circuit 40, and outputs ((e) and (f) in FIG. 19) are taken out at timings t1 and t2 at which the slope of the signal changes from positive to negative. .

A time measuring circuit 41 using a clock circuit or a time constant circuit or the like uses a time difference (t 2) between two peaks.
-T1) is measured.

On the other hand, the voltage at both ends of the transmission coil 11 is amplified by the buffer amplifier 42, and this signal is sent to the sample and hold circuit 43. The sample and hold circuit 43 is driven by a sampling pulse having a phase delay of 0 ° from the signal of the transmission coil 11, and samples the signal from the buffer amplifier 42.

When the coin C passes in front of the transmission coil 11, the output of the transmission coil 11 decreases due to a change in impedance caused by the coin C, and the output of the sample and hold circuit changes as shown in FIG. . This signal is input to a level detection circuit, and a timing t3 ((h) in FIG. 19) at which this signal falls below the reference level V is extracted.
The time difference measuring circuit 45 measures the time difference (t1 -t3) from t1. The reciprocal of this time difference (t1 -t3) 1 / (t1
-T3) is proportional to the passing speed of the coin (note that t2 may be used instead of t1).

The time difference (t2−t3)
-T1) is divided by the dividing circuit 46 to obtain this value (t2-
t1) / (t1 -t3) is the data of the conductivity or the thickness of the coin. A function g (x) for calculating the thickness obtained in advance by analysis or experiment in the arithmetic circuit 47 is calculated.
Alternatively, by substituting into the function f (x) for obtaining the material, the thickness d and the material σ of the coin can be quantitatively obtained by the following equation.

D = f {(t2−t1) / (t1−t3)} σ = g {(t2−t1) / (t1−t3)}

The result is compared with the specific numerical range of several types of coins stored in the storage circuit 49 in advance by the determination circuit 48, and if the value is within the range of any one of the coins, the specified coin is determined. It is determined that the coin is not within the range of the coin, and that the coin is a pseudo coin. This judgment signal is reset at the time of output of the level detection circuit 44 indicating that a coin has arrived, and is latched at the timing t2 of the differentiating circuit 40 indicating that the coin has passed. The coins are sorted by the coin sorting device 33 in the storing direction, the discharging direction, and the like based on the determination signal.

In the embodiment shown in FIG.
Timing t3 of the signal level change and the receiving coil 17
The passing speed of the coin is detected by the timing t1 of the first peak value from the output of the coin. However, there are various other methods of detecting the passing speed of the coin, for example, two coins along the coin moving direction. A coin detector (for example, a photoelectric detector or a detection coil) may be provided at two locations, and the passing speed of the coin may be detected based on a time difference between the two locations.

[0051]

As described above, in the coin discriminating apparatus of the present invention, the position of the eddy current generated in the coin changes depending on the thickness and the conductivity of the coin. Utilize the fact that the received output waveform becomes unimodal or bimodal due to the difference, or that the peak-to-peak distance changes depending on the thickness and conductivity of the coin even if it is bimodal. Then, the authenticity or the type of the coin is determined. Therefore, (a) Unlike the conventional apparatus shown in FIG. 20, there is no need to separately provide a transmission coil and a detector for coins for standard samples, so that the structure is simplified. (B) Since the reception output waveform changes to a single-peak type or a double-peak type due to a very small difference in the thickness and conductivity of the coin, it is possible to determine a very small difference in the thickness and conductivity of the coin. It is possible to discriminate coins with extremely high accuracy. (C) By utilizing the difference that the detected waveform becomes a single-peak type or a double-peak type, the number of peaks of the detected waveform is detected and coin discrimination is performed, so that no error occurs due to a difference in coin moving speed.
Further, since the distance between the peaks of the bimodal type is determined by the moving speed of the coin, no error occurs due to the difference in the moving speed of the coin. (D) Since the determination is made based on the number of peaks or the distance between the peaks of the bimodal type, there is no influence of level fluctuation due to drift such as temperature change. It has effects such as.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a relationship between a coin and a transmitting / receiving coil for explaining the principle of the present invention.

FIG. 2 is a diagram showing an eddy current generated in a coin and a magnetic field due to the eddy current.

FIG. 3 is a diagram showing a positional relationship between a coin and a transmission coil and an eddy current generated in a coin analyzed by a finite element method.

FIG. 4 is a diagram illustrating a positional relationship between a coin and a transmission coil and an eddy current generated in a coin analyzed by a finite element method.

FIG. 5 is a diagram showing a positional relationship between a coin and a transmission coil and an eddy current generated in a coin analyzed by a finite element method.

FIG. 6 shows a state in which the receiving coil is moved from the coin orbit 1 as shown in FIG.
FIG. 11 is a diagram illustrating an output waveform of a receiving coil when the conductivity of a coin is changed when the coin is fixed at 2.5 mm and the diameter of the coin is 16 mm.

FIG. 7 shows a state in which the receiving coil is moved from the coin orbit 1 as shown in FIG.
FIG. 11 is a diagram illustrating an output waveform of a receiving coil when the thickness of a coin is changed when the coin is fixed at 2.5 mm and the coin diameter is 16 mm.

FIG. 8 is a diagram showing a positional relationship between a coin size and a receiving coil.

FIG. 9 shows a receiving coil fixed at 15.0 mm from a coin orbit as shown in FIG.
FIG. 8 is a diagram showing an output waveform of a receiving coil when the conductivity of a coin is changed in the case of FIG.

FIG. 10 shows a receiving coil fixed at 15.0 mm from a coin orbit as shown in FIG.
FIG. 9 is a diagram illustrating an output waveform of a receiving coil when the thickness of a coin is changed in the case of m.

FIG. 11 is a diagram showing a positional relationship between a coin size and a receiving coil.

FIG. 12 is a diagram showing a schematic cross-sectional configuration of a coin orbit according to one embodiment of the present invention.

FIG. 13 is a view taken along the line AA in FIG.

FIG. 14 is a sectional view of a transmission / reception coil.

FIG. 15 is a block diagram of one embodiment of the present invention.

FIG. 16 is a diagram showing output waveforms of respective units in the block diagram of FIG. 15;

17 is a diagram illustrating an output waveform of the sample and hold circuit of FIG.

FIG. 18 is a block diagram of another embodiment of the present invention.

FIG. 19 is a diagram showing output waveforms of respective units in the block diagram of FIG. 18;

FIG. 20 is a configuration diagram of a main part of a conventional coin discriminating apparatus.

[Explanation of symbols]

 Reference Signs List 11 transmission coil 12 reception coil 26 sample hold circuit 27 sampling pulse generation circuit 31 waveform observation unit 32 determination unit 33 storage circuit 41 time measurement circuit 45 time measurement circuit 46 division circuit 47 calculation circuit 48 determination circuit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Noriyuki Kodama, Inventor 5-10-27 Minamiazabu, Minato-ku, Tokyo Anritsu Corporation (56) References JP-A-61-150093 (JP, A) JP-A-61 JP-A-62-89181 (JP, A) JP-A-6-215222 (JP, A) JP-B-47-30878 (JP, B2) International publication 93/7589 (WO, A1) (58) Field surveyed (Int.Cl. ⁶ , DB name) G07D 5/00-5/10

Claims (2)

(57) [Claims] 1. A transmitting coil disposed near a coin orbit and applying an alternating magnetic field to a coin moving on a coin orbit , and a transmitting coil disposed near the coin orbit and at a position receiving the magnetic field of the transmitting coil . Varies depending on thickness or material
Eddy current distribution in coins
A receiving coil formed to be smaller in diameter than another coin to detect the eddy current distribution as a change in induced voltage, and a signal extracting means for extracting a signal induced in the receiving coil.
A coin discriminating apparatus comprising: a stage; a peak number detecting means for detecting a peak number of a signal extracted by the signal extracting means; and a judging means for judging a thickness or a material of a coin from the peak number. 2. A transmitting coil disposed near a coin orbit and applying an alternating magnetic field to a coin moving on the coin orbit , and a transmitting coil disposed near the coin orbit and at a position receiving a magnetic field of the transmitting coil . Varies depending on thickness or material
Eddy current distribution in coins
A receiving coil formed to be smaller in diameter than another coin to detect the eddy current distribution as a change in induced voltage, and a signal extracting means for extracting a signal induced in the receiving coil.
A coin discriminating apparatus comprising: a stage; a peak radiation detecting unit that detects a width of two peaks of a signal extracted by the signal extracting unit; and a determining unit that determines a thickness or a material of a coin from the peak width.