JPS6211760B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a coin discrimination method for passing a coin through an alternating magnetic field and determining the appropriateness and type of the coin based on the degree of influence on the magnetic field.

(b) Prior Art A problem in such coin discrimination is the drift of the oscillation frequency, and in particular, a relatively high frequency alternating magnetic field is formed, and the change in frequency, which is the degree of influence on the magnetic field due to the passing of the coin, is This has caused errors when measuring plate thickness and diameter.
In other words, Figure 3 shows the signal waveform when inspecting the thickness or diameter of a plate.When a coin passes through a magnetic field that is oscillating at a frequency of fi in a standby state, the thickness or diameter of the plate is inspected. The inductance changes accordingly, and the oscillation frequency fluctuates up to fp. Conventionally, coins were identified by whether the value of fp was the same as that produced when a proper coin was placed in an alternating magnetic field. However, if the standby frequency fi fluctuates, the maximum frequency of change due to passage of the test coin will also fluctuate from fp, making accurate coin discrimination difficult. For this reason, Japanese Patent Laid-Open No. 48-29499 discloses a coin discrimination method in which the influence of fluctuations is canceled by adding or subtracting the fluctuation amount of the standby frequency from the maximum frequency of change.

(c) Problems to be solved by the invention The invention of the above publication does not solve the problem even if the standby frequency changes.
This is based on the recognition that the frequency change Δf when a coin passes through an alternating magnetic field is always constant.
However, if the frequency fluctuates as shown by the dotted line in FIG. 3 after measuring the standby frequency, the variation Δf' from the standby frequency fi becomes a value that includes an error, resulting in an erroneous determination.

Therefore, the present invention attempts to perform accurate measurement by detecting the standby frequency immediately before the coin passes. The present invention reliably detects the approach of coins and changes the waiting period at that time.
This provides a method for measuring wave numbers.

(d) Measures to solve the problem Placing a material inspection sensor that generates a low frequency electromagnetic field in front of the plate thickness and diameter sensor,
When this material inspection sensor detects the insertion of a coin, it detects the standby frequency of the plate thickness inspection sensor and diameter inspection sensor, and when the coin reaches these sensors and detects the maximum change frequency, the variation from this standby frequency is determined. . Then, the appropriateness of the coin is determined according to this variation, and when the appropriateness of the coin is determined based on the inspection result by the material inspection sensor, the coin is determined to be appropriate.

(e) Effect In material inspection, an alternating magnetic field is formed at a relatively low frequency so that the magnetic flux penetrates into the inside of the coin, so the oscillation frequency is stable and drift is small. Therefore, it is possible to reliably detect the arrival of a coin, and to measure the frequency of the plate thickness inspection sensor or diameter inspection sensor at this time is to measure the standby frequency just before the coin passes.

(F) Embodiment Figure 1 shows a schematic configuration of a coin sorting device,
4 is a coin input port, 5 is a coin passage where coins introduced from the coin input port 4 roll, 1 is a material inspection sensor,
2 is a plate thickness inspection sensor, 3 is a diameter inspection sensor,
6 is a return path 7 depending on whether the coin is proper or not.
Alternatively, the coin gate 9 distributes coins to the receiving passage 8, and the coin detector 9 detects the introduction of coins into the receiving passage 8. FIG. 2 shows the circuit configuration of such a coin sorting device. As shown in the figure, the material inspection sensor 1 includes an excitation coil 10, a reference coil 11, and a detection coil 1.
2, the excitation coil 10 is equipped with an oscillator 13
is connected to form a relatively low 3KHz electromagnetic field. When a low-frequency electromagnetic field is formed, the frequency change is small, so there is little drift, and the material inspection sensor 1 is very effective as a sensor for detecting the insertion of coins. On the other hand, the small frequency change means that the sensitivity for detecting the material of the coin is also low. In order to solve these contradictory objectives, the present invention measures the signal phase difference or voltage change due to the passing of a coin in the case of material inspection to largely grasp the degree of influence on the magnetic field. This has the advantage that the influence can be absorbed within the error range. Therefore, in this example, a case will be explained in which the phase difference between the signal waveforms of the reference coil 11 and the detection coil 12 when a coin passes through the coin passage 5 is detected.

The output signals of the reference coil 11 and the detection coil 12 are waveform-shaped by waveform shaping circuits 14 and 15, respectively.
It is introduced into the AND gate 16. On the other hand, since the clock pulse is introduced into the AND gate 16 from the clock pulse generation circuit 17, the AND gate 16
6 outputs a clock pulse corresponding to the phase difference of the output signals. Also, plate thickness inspection sensor 2
is made up of oscillating coils 18 and 19 connected in series with opposite phases across the coin passage 5, and is connected to an oscillator 20 to form an electromagnetic field with a relatively high frequency of 1 MHz.
The plate thickness inspection sensor 2 detects fluctuations in the oscillation frequency due to changes in mutual inductance depending on the distance between the oscillation coil 18 and the coin surface and the distance between the oscillation coil 19 and the coin surface when the coin passes through the coin passage 5. The thickness of the coin is measured based on this. On the other hand, the diameter inspection sensor 3 is equipped with an oscillation coil 21 that is connected to an oscillator 22 to form an electromagnetic field with a relatively high frequency of 1 MHz.As is clear from FIG. It is located. Therefore, when a coin passes, the difference in inductance due to the difference in the area of the overlap between the diameter inspection sensor 3 and the coin is used depending on the diameter of the coin, and by detecting the oscillation frequency, the diameter of the coin can be determined. It is used to measure. Further, 23 is a coin determining device, and 24 is a coin determining device 23.
When the control signal a is introduced, the AND gate 16
AND gate that outputs the clock pulse from
25 is an AND gate that outputs the oscillation signal of the oscillator 20 when the control signal b is introduced from the coin judging device 23; and 26 is an AND gate that outputs the oscillating signal of the oscillator 22 when the control signal c is introduced from the coin judging device 23.
AND gate, 27 is a counter.

With the above configuration, a coin inserted from the coin input port 4 first passes through the material inspection sensor 1, but in a standby state, the coin determination device 23 outputs a control signal a.
As the coin approaches the material inspection sensor 1, the phase difference signal increases as shown in FIG. 4B. When the phase difference counted by the counter 27 becomes larger than a predetermined threshold value S, the coin determining device 2
〓〓〓〓〓
3 outputs a control signal b to measure the standby frequency of the oscillator 20. The frequency is measured by counting the oscillation output with a counter 27 within a reference time of 1 ms, for example, and the coin determining device 23 outputs the control signal b for 1 ms, and the count value of the counter 27 during this period is used as the standby frequency f. Remember as ₁₁ . Next, the coin determining device 23 similarly outputs the control signal C for 1 ms and converts the count value of the counter 27 into the standby frequency of the oscillator 22.
Store as f ₂₁ . Therefore, the oscillators 20, 22
When the standby frequency is memorized, the coin determining device 2
3 outputs the control signal a again to introduce a clock pulse related to the phase difference into the counter 27. When the counter 27 detects the phase difference value ψ when the coin approaches the material inspection sensor 1, the coin determination device 23 compares it with a preset reference value for a genuine coin for each coin type, and determines which If the coin matches the reference value within the allowable error range, it is first determined that the coin is of a type related to the matched reference value in terms of material. When the determination regarding the material is completed, the coin determining device 23 outputs the control signal b every 1 ms to cause the counter 27 to receive the oscillation output of the oscillator 20. When the counter 27 detects the maximum frequency f ₁ of the oscillator 20 when the coin approaches the plate thickness inspection sensor 2, the coin determination device 23 determines the frequency based on the difference from the previously stored standby frequency f ₁₁ . Calculate the fluctuation amount and compare it with the preset standard value for specie coins for each coin type,
As described above, it is determined that the coin is of a type related to the matching reference value. When the plate thickness determination is completed, the coin determination device 23 outputs a control signal C every 1 ms to introduce the oscillation output of the oscillator 22 to the counter 27, and calculates the maximum frequency f of the oscillator 22 when the coin approaches the diameter inspection sensor 3 most. ₂ is counted by the counter 27, the frequency variation is calculated from the difference from the standby frequency _f21 . Then, the coin is compared with a preset standard value for genuine coins for each type of coin, and if they match, the coin is determined to be of the type corresponding to the standard value.

In this way, as the inserted coin rolls through the coin passage 5 and passes through the material inspection sensor 1, the plate thickness inspection sensor 2, and the diameter inspection sensor 3, its suitability and type are determined respectively, and all inspection results are If they match, the coin determining device 23 outputs signals A, B, C, and D indicating the coin type. When any one of the signals A, B, C, and D is output, the coin gate 6 is moved out of the base plate 28 by the action of a solenoid, and the coins from the coin passage 5 are introduced into the receiving passage 8. However, when the received coin is detected by the coin detector 9, the counting device of the vending machine receives a signal A.
Add and count the input amount according to B, C, and D. However, if the above three inspection results do not match, or if any one of them is determined to be inappropriate, the coin determination device 23 will not output the signals A, B, C, and D, and therefore the coin gate 6 will not output the signals A, B, C, and D. The coin is introduced into the return path 7 while remaining protruding from 28.

(G) Effects of the Invention According to the present invention, a material inspection sensor that forms a low-frequency electromagnetic field with stable oscillation and little drift is placed in front of a plate thickness sensor and a diameter sensor that form a high-frequency electromagnetic field. , the standby frequency of the plate thickness sensor and diameter sensor is detected by detecting coin insertion by the material inspection sensor. Therefore, since the standby frequency immediately before the coin passes is detected,
It is possible to accurately measure frequency fluctuations of these sensors due to coin passage without including drift. Moreover, immediately after coins are inserted, the rolling motion is unstable and the coins tend to vibrate back and forth, but in a low-frequency electromagnetic field, the magnetic flux penetrates, so they are not affected by vibration, and in this respect, the electromagnetic field is also low. It is effective to place a sensor that generates a high electromagnetic field in front of a sensor that generates a high electromagnetic field.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the coin sorting device, Figure 2 is a schematic diagram of the coin sorting device.
FIG. 3 shows a circuit configuration diagram, FIG. 3 shows a signal waveform diagram showing drift, and FIG. 4 shows an operation waveform diagram according to the present invention. 1...Material inspection sensor, 2...Plate thickness inspection sensor, 3...Diameter inspection sensor, 4...Coin slot, 5...Coin passage, 6...Coin gate, 7...
Return passageway, 8... Acceptance passageway, 23... Coin determination device.

Claims (1)

[Claims] 1. A coin discriminating device in which a low frequency magnetic field generating means for generating an electromagnetic field at a relatively low frequency and a high frequency magnetic field generating means for generating an electromagnetic field at a relatively high frequency are sequentially arranged along the rolling direction of the coin, When the coin first reaches the low frequency magnetic field generating means, the signal phase difference or voltage is detected, and based on this detected value, the suitability of the coin is determined, and the standby frequency of the high frequency magnetic field generating means is measured, and then the coin reaches the high frequency magnetic field generating means. When reaching the high frequency magnetic field generating means, after measuring the frequency of the high frequency magnetic field generating means, the variation from the standby frequency is calculated and the suitability of the coin is determined based on the value of this variation, and the coin is determined based on both of the above determinations. A coin discrimination method characterized by determining suitability.