JPH0632111B2 - Sensors and sensor circuits - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sensor and a sensor circuit used for identifying a currency defect.

[Conventional technology]

With the widespread use of vending machines and amusement machines, there has been a demand for machines that can process not only coins but also coins and paper defects. Moreover, these devices are required to be small and inexpensive.

However, since the identification of coins and the identification of paper defects are based on completely different principles, it has been difficult to realize a small and inexpensive device that can be used for both coins and paper defects.

As a conventional coin discrimination sensor, as shown in FIG. 2, generally, a bridge system utilizing a change in inductance of the detection coil 1 is known. In FIG. 2, 2 is a semi-fixed inductance, 3 and 4 are fixed resistors, and 5 is an AC power source.
When the coin approaches the detection coil 1, the inductance of the coil 1 changes, so that the voltage v _o changes and the coin can be identified.

On the other hand, a sensor using a magnetoresistive effect element as shown in FIG. 3 is used to detect a weak magnetism due to a magnetic substance contained in a printing ink such as a paper defect for identifying paper defect or securities. Identification machines are known. In FIG. 3, 11 is a permanent magnet, 12 is a magnetoresistive effect element, 13 is a substrate, 14, 15 and
16 is a terminal, 17 is a lead wire, 18 is a cover, and 19 is a case. The terminals 14 and 16 are connected to a constant voltage power supply, and the resistance change of the magnetoresistive effect element when paper defects pass near the magnetoresistive effect element is detected as a change in the voltage between the terminals 15 and 16. I have to. Two magnetoresistive effect elements are used,
In many cases, the terminal 15 is taken out from the center of the two.

[Problems to be solved by the invention]

In this way, since the detection principle is different for coins, paper defects, securities, etc., conventionally, identification machines with separate functions for coins and paper defects have been made, and are commonly used for coins and paper defects. The obtained machine also had to have at least one coin identification device and at least one paper identification device, which was disadvantageous in that it was large and expensive. It is an object of the present invention to overcome the above-mentioned drawbacks by enabling a single sensor to discriminate between coins and paper defects.

[Means for solving problems]

In order to achieve the above object, the sensor according to the present invention is characterized in that a magnetoresistive effect element for detecting characteristics of paper defects is attached to an iron core, and a coil for detecting characteristics of coins is wound around the iron core. And

Further, in the sensor circuit according to the present invention, a magnetoresistive effect element for detecting the characteristics of paper defects is attached to an iron core, and a coil for detecting the characteristics of coins is wound around the iron core, and three sides of the bridge circuit. And a DC power supply, a first connection in which the coil is the other side of the bridge circuit, and a second connection in which an exciting current of the iron core flows from the DC power supply to the coil. And a changeover switch for changing over the connection of the coil.

[Work]

In the present invention, one sensor is switched by a changeover switch, and a coil wound around an iron core having a magnetoresistive effect element is used as one side of a bridge circuit for coin identification, and the coil is used as a direct current for identification of paper defects. By connecting to a power source, both coins and paper can be identified.

〔Example〕

Embodiment 1 FIG. 1 is a schematic view showing an embodiment of the sensor of the present invention.
20 is a sensor and 21 is an iron core, which is made of a sintered magnetic material, a laminated magnetic material, or the like. A coil 22 is wound around the iron core 21, and the magnetoresistive effect element 12 is attached to the iron core 21, the coil 22, and the magnetoresistive effect element 12 to form a sensor 20. 17
Reference numerals a, 17b and 17c are lead wires of the magnetoresistive effect element, 18 is a cover, and 23a and 23b are lead wires of the coil 22. As will be shown later, the coil 22 is used as an inductance in the case of metal detection and as an exciting coil in the case of magnetic detection. The magnetoresistive effect element 12 is used for magnetism detection, and may be provided not at the center of the iron core as shown but at the end. Further, the magnetoresistive effect element 12 is formed by connecting two elements in series and connecting the lead wires 17a and 17c from both ends with two elements.
Although the lead wire 17b is taken out from the connecting portion of the element, the number of elements is not limited to two, and the detection of the resistance change of the magnetoresistive effect element is not limited to the three terminal method as shown in the figure.

Embodiment 2 FIG. 4 is a diagram showing an embodiment of the sensor circuit of the present invention.
In the figure, 31 and 32 are fixed resistors, 33 is a semi-fixed inductance, and 34 is an AC power source. 35 is an equivalent circuit of the sensor 20 of the present invention shown in FIG. 1, 36 is an inductance corresponding to the coil 22, 37 and 38 are resistors corresponding to the magnetoresistive effect element 12, 39 is a changeover switch, and 40 is excitation. DC power supply for 41
Is a power supply for magnetic detection, 42 is a limiting resistor, 43 and 44 are amplifiers, and 45 and 46 are output terminals.

When coins are identified using this sensor circuit, the changeover switch 39 is switched to the side and the inductance 36 (coil 2
2) is one side of the bridge circuit. Coil 22 of sensor 20
When a coin approaches to, the inductance of the coil 22 changes according to the type of coin, so the output voltage of the bridge circuit changes. The change in the output voltage is amplified by the amplifier 43 and output.

When using the sensor circuit for identifying printed matter such as paper defects, switch the changeover switch 39 to the
22 is connected to the excitation DC power supply 40. The coil 22 acts as an exciting coil, and the iron core 21 is magnetized. Therefore, the magnetoresistive effect element 12 shows a constant resistance value, but when a paper defect printed with ink containing a magnetic material passes near the magnetoresistive effect element 12, the magnetoresistive effect is generated by the magnetism of the magnetic material. The internal resistances 37 and 38 of the element 12 change according to the type of paper defect or the like. The magnetoresistive element is powered by the limiting resistor 42.
Since it is connected to 41, the amount of resistance change can be taken out. The amplifier 44 amplifies the amount of resistance change and outputs a signal.

In both cases of coin identification and paper identification, the outputs of the amplifiers 43 and 44 are input to devices for subsequent control such as sales, exchange, change payment, and distribution storage.

In order to stabilize the operation of the magnetoresistive effect element 12, it is desirable that the excitation power supply 40 is a constant current power supply, and the magnetic detection power supply 41 can be a constant voltage power supply or a constant current power supply. It goes without saying that the method for extracting the change in the resistance value of the magnetoresistive effect element 12 is not limited to the method shown in FIG.

〔The invention's effect〕

As described above, a sensor circuit is configured by using a sensor in which a detection coil wound around an iron core and a magnetoresistive effect element attached to the iron core are combined, and the detection coil is one side of a bridge circuit or an exciting coil. It is possible to extract a signal required for coin identification and a signal required for paper misidentification by a single sensor by switching whether or not to use the sensor and the sensor circuit. It is possible to use a structure in which the machine and the paper misidentification machine can be used in common, and therefore the currency misidentification mechanism can be simplified, and the overall configuration can be made small and inexpensive.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a sensor of the present invention, FIG. 2 is a diagram showing the principle of a conventional coin detection circuit, and FIG. 3 is a conventional paper defect detection sensor using a magnetoresistive effect element. FIG. 4 is a diagram showing an outline, and FIG. 4 is a diagram showing an embodiment of a sensor circuit of the present invention. 1 ... Detection coil, 2 ... Semi-fixed inductance, 3, 4 ... Fixed resistance, 5 ... Bridge power supply, 11 ... Permanent magnet, 12 ... Magnetoresistive effect element, 13 ... Board, 18 ... Cover , 20 …… sensor, 21 …… iron core, 22 …… coil, 35 …… sensor equivalent circuit, 36 …… inductance, 37, 38 …… internal resistance of magnetoresistive element, 39 …… changeover switch, 40… … Excitation power supply, 41 …… Magnetic detection power supply.

Claims (2)

[Claims] 1. A sensor characterized in that a magnetoresistive effect element for detecting characteristics of paper defects is attached to an iron core, and a coil for detecting characteristics of coins is wound around the iron core. 2. A sensor in which a magnetoresistive effect element for detecting characteristics of paper defects is attached to an iron core, and a coil for detecting characteristics of coins is wound around the iron core, three sides of a bridge circuit and an AC power source. A bridge circuit component, a DC power supply, a first connection in which the coil is the other side of the bridge circuit, and a second connection in which an exciting current of the iron core flows from the DC power supply to the coil. A sensor circuit comprising a changeover switch for changing over the connection of coils.