JPH0115112B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field of the Present Invention> The present invention relates to a coin sorting device that sorts coins using a detection coil.

<Prior art> Conventionally, devices for sorting out the authenticity, type, etc. of coins inserted into public telephones, vending machines, etc. have been disclosed in Japanese Patent Application Laid-open No. 58-43086 or Japanese Patent Application Laid-open No. 56-56.
No. 88589 proposes a device using a detection coil consisting of a first coil and a second coil.

However, the coin sorting device disclosed in JP-A No. 58-43086 first converts a square wave signal into a triangular wave.
A triangular wave current is supplied to the first coil to generate a magnetic field. Then, the coin is passed between the first coil and the second coil. The output signal from the second coil at this time is received by an amplifier circuit and output as a square wave signal. The gate circuit detects the presence of a coin by checking whether the square wave signal output from this amplifier circuit is at a predetermined level or higher. Coins are sorted by detecting the phase difference with the signal (the signal before being converted into the triangular wave).

In addition, the coin sorting device of JP-A No. 56-88589 is
Coins are sorted based on the phase change of the output signal of the coil as the coin passes.

<Problems to be Solved by the Present Invention> However, it is known that when a coin passes between the first and second coils, the output signal of the coil changes both in amplitude and phase.

However, in the coin sorting device disclosed in JP-A-58-87688, coins are sorted based on the voltage value obtained by rectifying the output signal of the coil with a rectifier circuit.
Only the amplitude change of the coil output signal is used as a criterion for selection, and the phase change of the coil output signal is not used as a criterion for selection. For this reason, it has been impossible to distinguish between two types of coins that have the same amount of amplitude change but different amounts of phase change.

Also, JP-A-58-43086 and JP-A-56-88589
In both cases, the coin selection criteria is based only on the phase change of the coil's output signal, so even if the amount of phase change is the same, it is impossible to distinguish between two types of coins because the amount of amplitude change is different.

It is an object of the present invention to provide a coin sorting device that solves these problems.

<Means for solving the above problems> In order to solve the above problems, the coin sorting device of the present invention includes: an oscillator; a first coil excited by an oscillation signal from the oscillator to generate an alternating magnetic field; and a second coil that is disposed opposite to a position receiving the alternating magnetic field from the first coil and outputs a signal whose amplitude and phase have changed in response to the inserted coin compared to when no coin is present. , a coin sorting device that sorts input coins based on the signal, comprising: a sample pulse generator that outputs a sampling pulse that is output one pulse per cycle in synchronization with the oscillation signal of the oscillator; a sample and hold circuit that samples and holds a voltage at a predetermined time point of an AC signal corresponding to the signal induced in the coil using the sample pulse, and outputs a DC voltage signal corresponding to the voltage; a setting means for presetting a setting value corresponding to an output value of the sample and hold circuit that is output based on a signal whose amplitude and phase have changed that is output from the second coil; and an output from the sample and hold circuit. and determining means for comparing the DC voltage signal with the set value of the setting means to determine the inserted coin.

<Function> As described above, in the coin sorting device of the present invention, the coil outputs an output signal whose amplitude and phase have changed depending on passing coins compared to when no coins are present. Then, the output signal whose amplitude and phase have changed is sampled at a predetermined point in each cycle by a sampling pulse that is output one pulse per cycle in synchronization with the oscillation signal of the oscillator, and is output as a DC voltage value. Ru. This DC voltage value is sampled and held for regular coins and compared with a preset value. Since the voltage value of the output AC signal from the coil whose amplitude and phase have changed is taken out at the time when the phase shifts, this voltage value synergistically includes both the amplitude change and phase change of the output signal of the detection coil. Therefore, sorting based on this can greatly improve the sorting accuracy compared to sorting based solely on amplitude changes or phase changes.

<Embodiment of the present invention> An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a coin trajectory. As shown in FIG. 2, the coin track 1 has a cover 3 mounted on the upper surface of a base plate 2 that is inclined with respect to the vertical and parallel to it at a predetermined distance. The rail 4 that guides the coins is installed at an angle with respect to the horizontal line, and the coin C inserted through the slot 5 has its ventral surface C' in contact with the top surface of the board 2 and its peripheral end surface C'' on the rail 4. They roll and fall along the rail 4 while in contact with each other.

The coin track 1 is bent in a dogleg shape, and a removal lever 7 is provided at the end of the upper half of the sorting track 1a to remove unsuitable coins from the track and drop them into the return slot 6. , the regular coins that have passed through the removal lever 7 are accumulated in the accumulation track 1b.

A pair of thickness detection coil T and material detection coil M are arranged at a position close to the input port 5 on the sorting track 1a to face each other at a predetermined distance in the coin thickness direction. That is, as shown in FIG. 2, the diameter detection coil T is attached to the upper surface of the cover 3, and the material detection coil M is attached to the lower surface of the substrate 2, facing the thickness detection coil T. As shown in FIG. 4, the pair of thickness detection coil T and material detection coil M are arranged close to the rail 4 so as to be covered by the regular coins of the minimum diameter that are inserted.

FIG. 5 is a block diagram of an electric circuit for sorting coins using detection coils T and M.

In FIG. 5, 8 is an oscillator that outputs a rectangular wave oscillation signal of a predetermined frequency, and 9 is a frequency divider.

The thickness detection coil T is excited by a rectangular wave signal of a predetermined frequency from a frequency divider 9 which divides the rectangular wave oscillation signal of the oscillator 8 to generate an alternating magnetic field, and is installed opposite to each other. The material selection coil M is excited by this alternating magnetic field and generates an induced voltage.
The thickness detection coil T forms a parallel resonant circuit with the capacitor 10, and when no coin is present, the output voltage appearing at both ends of the coil is maximized in tune with the frequency from the frequency divider 9. When the coin passes between the thickness detection coil T and the material detection coil M, the impedance of the thickness detection coil T changes and goes out of tune, causing the output voltage to drop. As shown in FIG. 2, this impedance change increases as the distance from the surface of the coin C to the thickness detection coil T decreases (that is, as the thickness of the coin C increases). The greater the thickness, the lower the output voltage. Similarly, the material detection coil M forms a parallel resonant circuit with the capacitor 11, and when a coin passes between the thickness detection coil T and the material detection coil M, the output voltage is maximum when no coin is present. , due to a change in the impedance of the material detection coil M, the tuning is lost and the output voltage decreases. Furthermore, since the material detection coil M is excited by the thickness detection coil T and generates an induced voltage, when a coin passes between the material detection coil M and the thickness detection coil T, the excitation voltage by the thickness detection coil T increases. At the same time, the alternating magnetic field that reaches the material detection coil M changes due to the difference in the material and thickness of the coin, and the induced voltage generated in the material detection coil M decreases.

In FIG. 5, 22 is a resistor, and 12 and 13 are AC amplifiers that amplify the output signals of the detection coils T and M, respectively.

14 and 15, the amplitude and phase are determined by the coins in the AC amplifiers 12 and 13 by the sampling pulse from the frequency divider 9, which has the same frequency as the signal that drives the detection coil T and is tuned to one pulse per cycle. This is a sample-and-hold circuit that samples and holds the voltage value at a predetermined time point of the output AC signal that has changed (with respect to when no coins are present), and outputs it as a DC voltage value.

The sample and hold circuit 14 includes an analog switch 23, a capacitor 25, and a high input impedance operational amplifier 27. The analog switch 23 is turned on when receiving the sampling pulse from the frequency divider 9, and the AC amplifier 1 at this time is turned on.
The output voltage of 2 is stored in the capacitor 25.
The high input impedance operational amplifier 27 is a high voltage follower circuit with a gain of 1, and outputs the same voltage as the voltage input to the non-inverting input terminal. Capacitor 25 is high input impedance operational amplifier 2
Since the time constant between the capacitor 25 and the high input impedance operational amplifier 27 can be made sufficiently large compared to the sampling pulse interval, the capacitor 25 is connected to the non-inverting input of the high input impedance operational amplifier 27 until the next sampling pulse arrives. 25 holds the previous voltage. The sample hold circuit 15 also has a similar configuration.

Reference numeral 16 denotes an A/D converter that converts analog voltages output from the sample and hold circuits 14 and 15 into digital values.

17 is a coil T, which sets a setting value including both amplitude and phase information of a detection signal regarding a regular coin in advance.
There are two types of memory settings for coil M, and A/
The two types of digital values from the D converter 16 are compared with these set values to determine the authenticity and type of the coin, and if the coin is a genuine coin, the correctness is determined to allow the coin to pass through the removal lever 7. This is a determination circuit that outputs a signal.

That is, this determination circuit 17 samples the alternating current signal whose amplitude and phase have changed, which is output from the first and second parallel resonant circuits when a regular coin passes within the coin orbit, using the sample and hold circuit. a setting means in which a set value corresponding to a DC voltage value when held is set in advance; and a determining means for comparing the DC voltage value outputted from the sample hold circuit with the set value to determine a coin. We are prepared.

Reference numeral 18 denotes a transistor that is turned on by a proper signal from the discrimination circuit 17, 19 is an electromagnet that is energized when the transistor 18 is turned on, and 20 is a protection diode.

As shown in FIG.
The permanent magnet 21 is rotatably attached to the bottom side of the
The tip 7a protrudes into the coin track 1. When the electromagnet 19 is energized, its magnetic force is generated in a direction that cancels the attractive force of the permanent magnet 21. Therefore, the coin pushes away the tip 7a of the removal lever 7 and advances to the accumulation track 1b.

FIG. 6 is a time chart showing the circuit operation of FIG. 5, and the circuit operation of FIG. 5 will be explained using this time chart.

In FIG. 6, a is a rectangular wave signal sent from the frequency divider 9 to the thickness detection coil T, and b is a sampling pulse of the same frequency sent to the sample and hold circuits 14 and 15.

The high frequency component of the rectangular wave is removed from the thickness detection coil T by the resonance circuit with the capacitor 10, and a sine wave signal is output. The solid line in FIG. 3C shows the output signal of the AC amplifier 12. The amplitude of this sine wave signal becomes smaller while the coin passes through the thickness detection coil T and the material detection coil M (indicated by symbol A in FIG. 7).

The sample-and-hold circuit 14 samples and holds the level of the AC signal at a predetermined point in time, the amplitude and phase of which have changed with respect to when no coins are present, using the sampling pulse shown in b, thereby obtaining the level shown in FIG. 6c.
It is converted into a change in DC voltage as shown by the chain line. That is, when a coin passes, a voltage value is output at a time when the voltage value deviates from the peak value due to a phase shift with respect to when a coin is absent. Therefore, this output voltage value is obtained as a result of adding together both the amplitude change and the phase change of the AC signal due to the coin.

The output signal of the material detection coil M is an AC signal whose amplitude and phase change depending on the material of the coin when the coin passes. and the phase change is converted into a synergistic DC voltage change.

The solid line in FIG. 6d shows the output signal of the AC amplifier 13, and the chain line shows the output signal of the sample and hold circuit 15.

The influence of the material of the coin, etc. causes a change in the phase of the output signal of the coil, as shown in an enlarged view in FIG. 7, in addition to a change in the voltage of the output signal of the coil.

In FIG. 7, a shows the output signal of the frequency divider 9 sent to the detection coil T, b shows the sampling pulse from the frequency divider 9, and a solid line c shows the output signal of the AC amplifier 13. The dashed line at c indicates the conventional rectifying and smoothing circuit output voltage. That is, since a delay occurs due to the time constant of the smoothing circuit, changes in the peak voltage of the waveform cannot be followed. On the other hand, the dotted line shows the waveform of the sample and hold circuit output, and the voltage signal sampled and held by generating sampling pulse b at the center point of the pulse width of signal a has the following characteristics:
Both the change in the output voltage of each coil and the phase change due to the passing of a coin are synergistically included.

A/D converter 16 is sample hold circuit 1
Two types of output voltages, No. 4 and 15, are converted into two types of digital values. The determination circuit 17 detects the two lowest digital values from the A/D converter 16, respectively. The authenticity and type of the coin are determined by comparing the digital value indicating the two lowest values with two pre-stored digital values related to regular coins. It is driven for a certain period of time while passing through 7.

FIG. 6e shows the signals driving transistor 18.

FIG. 8 is a diagram showing the maximum value of the phase change when a disc made of a different material and having the same thickness and diameter as a 100 yen coin passes through a coil M made of material.

Figure 9 shows that the disk used in Figure 8 is made of coil M.
The maximum amount of change in the output of the sample-and-hold circuit and the maximum amount of change in the output of the smoothing circuit when the signal passes through are compared.

It can be seen from FIG. 9 that the amount of change in the output of the sample and hold circuit is larger than the amount of change in the output of the smoothing circuit. That is, by using the sample and hold circuit, the amount of change appears larger, so the S/N ratio is improved and the detection accuracy is improved.

<Effects of the Present Invention> As explained above, the coin sorting device of the present invention samples and discriminates the voltage value at a predetermined time point of the output AC signal whose amplitude and phase have changed with respect to the absence of a coin, so that it is possible to distinguish between amplitude changes and Since discrimination is based on data that synergistically includes both phase changes, discrimination accuracy is significantly improved compared to conventional discrimination based only on amplitude or phase.
Misjudgment will be eliminated.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing the arrangement of a detection coil, etc. in a coin track according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of FIG. 1, and FIG. 3 is a cross-sectional view showing the configuration of a removal lever. Figure 4 is a diagram showing the relationship between the coin size and the installation position of the detection coil, Figure 5
6 and 7 are time charts showing the operation of the circuit in FIG. 5. FIG. 8 is a diagram showing changes in the phase of the material detection coil M output with respect to changes in material. FIG. 9 is a diagram showing a comparison of the amount of change in the outputs of the sample hold circuit and the smoothing circuit. 1... Coin track, 2... Board, 3... Cover,
4... Rail, 5... Inlet, T... Thickness detection coil, M... Material detection coil, 7... Exclusion lever, 8... Oscillator, 9... Frequency divider, 10, 11...
...Capacitor, 12, 13...AC amplifier, 1
4, 15...sample hold circuit, 16...
A/D converter, 17... Judgment circuit, 23, 24...
...Analog switch, 25, 26...Capacitor, 27, 28...High input impedance operational amplifier.

Claims (1)

[Scope of Claims] 1. An oscillator, a first coil excited by an oscillation signal from the oscillator to generate an alternating magnetic field, and arranged facing each other at a position receiving the alternating magnetic field from the first coil, and a second coil that outputs a signal whose amplitude and phase are changed compared to when no coin is present in accordance with the inserted coin, and which sorts the inserted coins based on the signal, the coin sorting device as described above. a sample pulse generator that outputs a sampling pulse that is output one pulse per cycle in synchronization with an oscillation signal of an oscillator; A sample-and-hold circuit that samples and holds by pulse and outputs a DC voltage signal corresponding to the voltage, and a signal that is output from the second coil when a regular coin is inserted and whose amplitude and phase have changed. a setting means for presetting a set value corresponding to the output value of the sample and hold circuit outputted by the sample and hold circuit; A coin sorting device characterized by comprising: a determining means for making a determination.