JPS6237432B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coin sorting device that electromagnetically sorts coins in public telephones, various vending machines, and the like.

[Conventional technology]

2. Description of the Related Art Conventionally, various devices have been used, for example, in public telephones, etc., to electrically or magnetically sort coins based on differences in outer diameter, material, etc.

FIG. 1 shows an example of this type of coin sorting device that is conventionally used. In the figure, 1 is a stabilization circuit, 2 is an oscillation circuit, 3 is a detection coil, 4 is an amplifier circuit, 5 is a rectifier circuit, and 6 is a comparison circuit, to which a power supply voltage V is applied by inputting a power supply signal a. . The detection coil 3 includes a pair of transmitter coil 3a and receiver coil 3b, which are arranged opposite to each other across the coin path and are electromagnetically coupled to each other.

In the coin sorting device having the above configuration, when a coin 7 is placed between the transmitting coil 3a and the receiving coil 3b, the voltage induced in the receiving coil 3b changes because the magnetic permeability varies depending on the material. Therefore, this voltage signal is amplified and rectified by an amplifier circuit 4 and a rectifier circuit 5, and a comparison circuit 6 determines whether the obtained DC voltage level falls within a reference voltage level band preset according to each type of coin. The materials can be selected based on the output discrimination signal b.

[Problem that the invention seeks to solve]

However, in such a coin sorting device, since the judgment level band in which the comparator circuit 6 has good resolution is limited, one set of sorting circuits having the above-mentioned configuration is used to distinguish between a plurality of coins each having a different magnetic permeability. It is difficult to sort all types of coins with high accuracy, and in order to obtain high sorting accuracy for each type of coin, it is necessary to use similar amplification circuits and comparison circuits with corresponding amplification factors and judgment level bands. It is necessary to provide as many sorting circuits as there are types of coins to be sorted. However, this naturally complicates the structure, increases the size of the device, and increases manufacturing costs. For this reason, it has been desired to realize a coin sorting device that can perform material sorting with extremely high accuracy regardless of the type of coin by using one set of sorting circuits.

[Means for solving problems]

According to the present invention, a variable gain circuit is provided in an amplifier circuit that amplifies the output of a receiving coil, and the variable gain circuit changes the gain according to a coin type signal from a coin identification circuit that identifies the shape or weight of a coin.

[Effect]

The coin identification circuit sends out a coin type signal according to the expected coin type based on the shape and weight of the coin. In response to this signal, the variable gain circuit adjusts the gain of the amplifier circuit according to the material of the coin of the type, so that the output level of the amplifier circuit is within a high resolution level range of the comparator for determining the material. change by a predetermined amount. Therefore, regardless of the type of coin, the comparator always makes determinations in a high resolution level band.

〔Example〕

FIG. 2 is a block diagram showing one embodiment of the present invention. This embodiment is an example in which the present invention is applied to a public telephone set, and a central office power supply is used as the power supply.
In the figure, 10 is a power supply section, 11 is a diode bridge circuit, 12 is a power supply circuit, 13a is a dial contact Di, 13b is a short-circuit contact Ds, 14 is a communication circuit, and 15 is a power switch. switch 15
When the power supply circuit 1 operates upon receiving the power supply signal a, the power supply circuit 1
A power supply voltage V is supplied from 2 to the material selection circuit.
Note that the diode bridge circuit 11 has a terminal
This is to keep the polarity of the input to the power supply circuit 12 constant regardless of the polarity of the DC voltage from the exchange connected to L ₁ and L ₂ . Further, when the dial is turned, the dial contact 13a opens and closes the number of times corresponding to the dialed number to send and notify the exchange of the other party's number, and the short-circuit contact 13b closes at this time to short-circuit the communication circuit 14. Dial pulses are prevented from entering the communication circuit 14.

Further, 16 is a stabilizing circuit that stabilizes the power supply voltage, 17 is an oscillation circuit, 18 is a detection coil, 19 is an amplifier circuit, 20 is a rectifier circuit, and 21 is a comparison circuit. The detection coil 18 consists of a pair of transmitting coil 18a and receiving coil 18b, which are arranged opposite to each other across the path of the coin 22 and are electromagnetically coupled to each other. Their basic structure and operation are similar to those shown in FIG.

Here, the amplifier circuit 19 includes an analog switch 23 for selecting, for example, three types of coins.
₁ and a variable resistor 24 ₁ , an analog switch 23 ₂ and a variable resistor 24 ₂ , and an analog switch 23 ₃ and a variable resistor 24 ₃ are connected in parallel. Coin type signals d ₁ , d ₂ , and d ₃ are selectively input to these series circuits from an outer diameter identification circuit 27 (described later) via level conversion buffers 25 ₁ , 25 ₂ , and 25 ₃ , respectively. . and analog switch 2
The gain of the amplifier circuit 19 changes depending on which one of 3 ₁ , 23 ₂ , and 23 ₃ is turned on. FIG. 3 shows a specific example of the configuration of such an amplifier circuit 19. In the figure, A is an amplifier, R ₁ to R ₆ are resistors, and C ₁ to _{C 3} are capacitors. Resistance R ₁ and
R ₂ is a bias resistor and an impedance adjusting resistor, respectively, and a capacitor C ₁ is a coupling capacitor for the rectifier circuit 20 in the next stage. terminal
Between T ₁ and T ₂ , each analog switch 23 ₁ ,
23 ₂ , 23 ₃ and variable resistors 24 ₁ , 24 ₂ , 24
A parallel circuit of 3 series circuits consisting of ₃ is connected.

In FIG. 2, coin type signals d ₁ , d ₂ , d ₃ from the coin outer diameter identification circuit 27 are simultaneously sent to the gate circuit 2.
6 is also input. This gate circuit 26 sends out the power signal a to the switch 15 when any one of the coin type signals d ₁ , d ₂ , and d ₃ is input.

In the above configuration, when material selection is performed, first, the outer diameter identification circuit 2
At step 7, it is determined which of three predetermined outer diameters the inserted coin 22 has. Such a coin outer diameter identification device is configured as follows using, for example, two sets of photoelectric detectors.

FIGS. 4 and 5 show an example of such a coin outer diameter identification device, and are a layout diagram of a photoelectric detector and a block diagram of an identification logic circuit, respectively. In FIG. 4, a pair of light emitting elements 31a and light receiving elements 3 face each other with a coin passage 30 in between.
2a, first and second photoelectric detectors each consisting of a light emitting element 31b and a light receiving element 32b are mounted at regular intervals. The outputs of the light receiving elements 32a and 32b mounted in this manner are input to the identification logic section shown in FIG.

In FIG. 5, the light receiving element 32a is connected to the passage 30.
A pulse having a pulse width t ₁ corresponding to the time during which the falling coin 22 is detected by the light receiving element 32a is sent to the timer 33. In addition, the light receiving element 32b
sends out to the timers 33 and 34 a pulse with a pulse width t ₂ corresponding to the time during which the coin 22 is detected by the light receiving element 32b. Both of these light receiving elements 3
The rising timings of the pulse outputs 2a and 32b have a time difference of t ₃ corresponding to the distance between the two light receiving elements. The timer 33 is connected to the light receiving element 32.
By starting the operation with the rise of the output of the light receiving element 32b and stopping the operation with the rise of the output of the light receiving element 32b, the time _t3 is measured and sent to the arithmetic circuit 35 as a pulse output. On the other hand, the timer 34 measures the time _t2 and sends it as a pulse output to the arithmetic circuit 35.
Send to. The arithmetic circuit 35 operates on both of these timers 3.
The ratio of t ₂ /t ₃ is calculated using the outputs of 3 and 34 as input, and the result is sent to the discrimination circuit 36 . The discrimination circuit 36 has a preset ratio t ₂ /t ₃ of coins with regular outer diameters, and this preset ratio t ₂ /t ₃ and the ratio input from the calculation circuit 35
Comparison and determination with t ₂ /t ₃ are performed.

Here, the falling speed of the coin 22, ie, the time _t3 required to fall a certain distance, does not change depending on the outer diameter of the coin 22. On the other hand, the light receiving element 3
Since the output pulse width t ₂ of 2b changes in proportion to the outer diameter of the coin 22, the ratio t ₂ /t ₃ changes if the outer diameter is different, so if the outer diameter is normal depending on the type of each coin. By comparing the ratio t ₂ /t ₃ , the outer diameter of the coin can be easily identified. In addition, in this case, if dust or the like accumulates in the passage 30 and the coins 22
Even if the falling speed of the output pulse becomes slower, the value of the ratio t ₂ /t ₃ remains unchanged because t ₃ increases in proportion to the increase in the output pulse width t ₂ . Therefore, accurate identification is possible even in such cases.

If the result identified by the coin outer diameter identification circuit 27 in this way corresponds to any of the three predetermined outer diameters of coins, then the coin type signals d ₁ , d are generated according to the type. Either of ₂ and _d3 is input to the material selection circuit shown in FIG. 2 as a pulse signal with a pulse width of approximately 50 ms. In addition,
The coins that do not correspond to the above fall into the ejection port.

In FIG. 2, the coin type signals d ₁ , d ₂ , d ₃
The switch 15 is actuated by a pulse input of one of them, for example, _d1 , and a power supply voltage is supplied to this material selection circuit. During this time, the coin 22 is located between the transmitting coil 18a and the receiving coil 18b. On the other hand, this coin type signal d ₁ is converted to a voltage at a predetermined level by the buffer 25 ₁ and turns on the analog switch 23 ₁ . At this time, the other analog switches 23 ₂ , 23 ₃ output the coin type signals d ₂ ,
It remains closed because d ₃ is not entered. As a result, the amplifier circuit 19 has a gain determined by the variable resistor ₂₄₁ . Therefore, the receiving coil 18
The output voltage b is amplified by the gain determined as described above in the amplifier circuit 19, converted to a DC voltage in the rectifier circuit 20, and then input to the comparison circuit 21. The comparison circuit 21 compares this input voltage level with a predetermined reference voltage level band, and if it falls within the level band, determines that the coin 22 has a predetermined material and outputs a discrimination signal b. do. If the coin 22 does not have the proper material, the output voltage of the receiving coil 18b will not reach the predetermined level, and the above-mentioned sorting system will not operate normally and will not output the predetermined discrimination signal b. , it is possible to eliminate counterfeit currency.

Here, the value of the variable resistor 24 ₁ is such that the gain of the amplifier 19 determined by the variable resistor 24 ₁ is such that when the coin 22 is a regular coin of the type corresponding to the coin type signal d ₁ , Adjustment is made so that the level of the voltage amplified by the amplifier circuit 19 and input to the comparator circuit 21 via the rectifier circuit 20 falls within the level band with the best resolution of the comparator circuit. . In this case, it goes without saying that the reference voltage level band of the comparison circuit 21 is also set to a level band with good resolution. Therefore,
It is possible to determine with high accuracy whether or not the coin 22 is made of a regular material.

Similarly, when the coin type signal d ₂ or d ₃ is input according to the outer diameter identified by the coin outer diameter identification circuit 27, only the analog switch 23 ₂ or 23 ₃ is turned on, and the amplifier circuit 19 The gain of is determined by the variable resistor 24 ₂ or 24 ₃ , respectively. In this case as well, the variable resistor 24 ₂
and 24 ₃ are the respective variable resistors 24
₂ or 24 ₃ is determined by the gain of the amplifier 19 when the coin 22 is a genuine coin of the type corresponding to the coin type signal d ₂ or d ₃ .
Since the level of the voltage amplified by 9 and input to the comparator circuit 21 via the rectifier circuit 20 is set to a value that falls within the highest resolution level band of the comparator circuit, the coin 22 However, it is possible to determine with high accuracy whether or not each coin has the proper material for a coin of the corresponding outer diameter.

That is, the level of the voltage input from the receiving coil 18b to the amplifier circuit 19 changes depending on the type of coin 22 and the material of the coin 22. Therefore, the coin type signals d ₁ , d ₂ , d ₃ from the coin outer diameter identification circuit 27
The input voltages have different levels depending on which one is input. However, the values of the variable resistors 24 ₁ , 24 ₂ , 24 ₃ are set according to the materials of the three types of coins to be sorted as described above, and they are set as the coin type signal.
By connecting to the amplifier circuit 19 according to d ₁ , d ₂ , and d ₃ and changing the gain of the amplifier circuit 19, the voltage input to the comparator circuit 21 via the rectifier circuit 20 is always connected to the comparator circuit 19. It is possible to set the level to a constant level in the level band with the best resolution of 21. Therefore, for all three types of coins having different magnetic permeabilities, it is possible to determine with high precision whether the inserted coin is a genuine coin or not.

In addition, the coin material selection circuit having the above configuration,
It is not always in a standby state, but the coin outer diameter identification circuit 27 identifies which of the three types of coins the outer diameter of the inserted coin corresponds to, or whether it does not correspond to any of the outer diameters of the three types of coins. As a result, only when one of the coin type signals d ₁ , d ₂ , and d ₃ is sent out as a pulse with a width of 50 ms, the switch 15 is turned on and the power supply voltage is supplied. Therefore, power consumption can be significantly reduced. This is extremely useful in public telephones using central power supply.

In addition, in the above-mentioned embodiment, only the case where a circuit for identifying the outer diameter of a coin is used as the coin identification circuit has been described, but the present invention is not limited to this, and the coin identification circuit may be, for example, A circuit that identifies the weight, thickness, contour pattern, etc. of a coin may be used.

〔Effect of the invention〕

As explained above, according to the present invention, by using a variable gain circuit, it is possible to perform material selection with extremely high accuracy for any of a plurality of types of coins using one set of material selection circuits. It is possible to simplify the process, downsize the device, and reduce manufacturing costs. Further, by turning on the power switch of the material selection circuit in response to the coin type signal from the coin identification circuit, various excellent effects such as being able to significantly reduce power consumption are achieved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a conventional coin sorting device, Fig. 2 is a block diagram showing a material sorting circuit in an embodiment of the present invention, and Fig. 3 shows a specific example of the configuration of its amplifier circuit section. The circuit diagram, FIG. 4 is a photoelectric detector arrangement diagram of the outer diameter identification device, and FIG. 5 is a block diagram showing the identification logic circuit. 15...Power switch, 17...Oscillation circuit, 1
8a... Transmission coil, 18b... Receiving coil, 1
9...Amplification circuit, 20...Rectification circuit, 21...Comparison circuit, 22...Coin, 23 ₁ , 23 ₂ , 23 ₃
...Analog switch, 24 ₁ , 24 ₂ , 24 ₃
... Variable resistance, 26 ... Gate circuit, 27 ... Coin outer diameter identification circuit, 30 ... Coin passage, 31a, 3
1b... Light emitting element, 32a, 32b... Light receiving element, 33, 34... Timer, 35... Arithmetic circuit,
36...Discrimination circuit.

Claims (1)

[Claims] 1. In a coin sorting device that identifies the shape or weight of a coin by a coin identification circuit, and then sorts the material of the coin by a coin material sorting circuit, the coin material sorting circuits are arranged opposite to each other across a coin path. A transmitting coil and a receiving coil are arranged, an amplifier circuit that amplifies the output of the receiving coil, a rectifier circuit that converts this amplified output into a DC voltage, and a rectified output that is set in a level band with good resolution in advance. A comparison circuit outputs a discrimination signal by comparing it with a reference value, and a gain of the amplifier circuit is changed according to a coin type signal sent from the coin identification circuit, and the rectified output is adjusted to A coin sorting device comprising: a variable gain circuit that adjusts to a predetermined level band according to a reference value.