JP2002528829A - Apparatus and method for identifying bimetallic coins - Google Patents

Abstract

(57) Abstract: A coin identification device comprises first and second arranged to induce and detect eddy currents in an outer ring (40) and an inner disk (50) of a bimetallic coin (30), respectively. It has coils (10, 20). The storage device stores the coin reference data, and the logic device determines the identity of the coin by comparing the coin reference data with data on the conductivity of the coin obtained from the detected eddy current. A magnetic sensor (60) is coupled to the logic device such that when the coin (30) is between the first and second coils and the magnetic sensor, one of the first and second coils (10, 20) Arranged to detect a magnetic field generated by at least one. The logic device uses data on the magnetic permeability of the coin obtained by the magnetic sensor when determining the identity of the coin (30).

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD The present invention relates to a coin identification device of the type having first and second coils arranged to induce and detect eddy currents in an outer ring and an inner disk, respectively, of a bimetallic coin. In this device, the storage device stores coin reference data, and the logic device compares the coin reference data with the data on the conductivity of the coin obtained from the detected eddy current to thereby determine the coin reference data. Determine identity.

The invention also relates to a method for identifying bimetallic coins and to a coin processor including a coin identification device of the type described above. Description of the Prior Art A coin discriminator arranged to measure the electrical characteristics of a coin, such as resistance or conductivity, by applying a magnetic pulse to the coin and detecting the decay of the eddy current induced in the coin is Are well known in the art. This type of coin discriminator is used in various coin processing machines such as coin counters, coin sorters, coin checkers for vending machines and game machines. Known coin handling machines are disclosed, for example, in WO 97/07485 and WO 87/07742.

[0003] The operation of such a coin discriminator is described, for example, in EP-B-0 119 000, in which the coin inspection arrangement comprises a transmitter coil and the transmitter coil comprises a magnetic pulse. , And a magnetic pulse is induced in the coil as the coin passes through the transmitter coil along the coin rail. The eddy currents thus created in the coin create a magnetic field, which is monitored or detected by the receiver coil. The receiver coils can be separate coils or alternately constituted by transmitter coils having two modes of operation. Since the rate of decay of the eddy current induced in the coin is a function of the conductivity of the coin, monitoring this decay can provide a value or reading indicating the conductivity of the coin.

[0004] One embodiment of EP-B-0 119 000 uses two transmitter coils with different effective areas. Large coils are larger than the maximum allowed coins and small coils are smaller than the minimum coin. The position of the small coil is such that the smallest coin is
The position is such that the effective cross-sectional area of the coil is covered by the smallest coin when passing along the rail.

[0005] The purpose of the small coil is to solve the problems that can arise when only large coils are used. The reading from the large coil is a function of the conductivity and diameter of the coin. The large diameter and high conductivity both increase the reading of the coin. Thus, there is the problem that coins of different diameters and conductivity can produce the same reading. For example, a British two penny copper coin and a 2 mm smaller diameter aluminum token would produce the same reading from a larger coil. Small coils produce a signal that is dependent on conductivity, regardless of diameter. Thus, aluminum and copper can be distinguished by small coils. Coins of the same material but different diameters produce the same readings, so small coils cannot be used alone.

[0006] Another prior art coil discriminator is disclosed in EP-B-0 300 781. While the coil discriminator described above is often sufficient for traditional homogeneous coins made of a single metal or metal alloy, the prior art discriminator described above has a bimetallic disc, as described briefly below. Coins are not very useful for identifying them properly.

In recent years, bimetallic coins have been on the market in various countries. Examples of well-known bimetallic coins are the French 10 franc coin, the British 2 pound coin, the Canadian 2 dollar coin and the 1 and 2 euro coins. Bimetallic coins are made as follows. The outer ring and center disk are stamped from two metal or metal alloy sheets (also known as blanks) that make up the bimetallic coin. Next, the disc is fitted into a ring and coins are cast. Casting is performed by pressing a coin between two curing dies. The die stamps the coin with the front and back patterns to make the disc and ring one. The joint between the disk and the ring is called a bond.

[0008] In identifying bimetallic coins, three conductivity factors are considered. That is, the inner disk, the outer ring and the bond between them. The conductivity of the inner disk and outer ring depends on the metal used and does not change. However, the conductivity of a bond between two metals can vary widely. A bond is a perfect conductor when the surface of a freshly cut metal is pressed hard (molecular welding). However, if the inner disk and outer ring are covered with a layer of oxide before joining, the bond will be less conductive. In the extreme case, where there is a thick oxide layer, the bond does not conduct at all. Furthermore, the conductivity of the bond is
It is further complicated because it also depends on the voltage of the eddy current induced for the measurement. Higher measured voltages "penetrate" through the oxide layer and exhibit higher conductivity than at lower voltages. In coin discriminators, the voltage between bonds is small and this non-linear effect is significant.

As a result, the poor definition of bond conductivity in bimetallic coins has caused problems for many existing coin discriminators. In the case of bimetallic coins, positive variability of coins is made more difficult because the variability of the bond varies the readings from coins of the same type. For example,
In the dual transmitter coil arrangement of EP-B-0 119 000, the small coils are placed near the coil rails (so as to cover very small single metal coins), so they are An eddy current is generated, which causes a large uncertainty in the bond conductivity reading.

[0010] GB-A-2 323 200 discloses a coin validator for bimetallic coins. The elliptical sensor 16 induces eddy currents, which are limited to the outer ring of the bimetal coin. This eddy current is detected and used to measure the conductivity of the outer ring. A separate smaller coil 14 is used to measure the conductivity of the center disk of the bimetal coin.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved coin identifier for identifying bimetallic coins. Furthermore, it is an object of the present invention to enable a coin discriminator to be realized with a small number of components. The above object is achieved by a coin identification device, a bimetal coin identification method and a coin processing machine according to the attached independent claims.

[0012] Other objects, features and advantages of the invention are the subject of the dependent claims. The present invention will be described in more detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE INVENTION As shown in FIGS. 1 and 2, the coin discriminator comprises a large coil 10 and a small coil 20, both of which are mounted on a support 80. The coils 10, 20 are connected to an electrical device (not shown) for applying a voltage pulse thereto.

The bimetallic coin 30 comprises a ring 40 of a first metal or alloy and a disk 50 of a second metal or alloy. The bond between the disc and the ring is labeled 90. Coils 10, 20 are transmitters for applying magnetic pulses to bimetallic coins 30, respectively, passing coin identifiers along coin rails 70 to create eddy currents in outer ring 40 and inner disk 50 of coin 30. -Acts as a coil. In addition, coils 10, 20 act as receiver coils for detecting magnetic field fluctuations caused by eddy currents in outer ring 40 and inner disk 50 and converting them into corresponding voltage signals. The voltage signal is provided to a detector (not shown) arranged to measure the signal decay and in response determine the respective conductivity values of outer ring 40 and inner disk 50. The determined conductivity value is then used to identify the coin 30.

The coin discriminator is arranged to make a conductivity measurement when the center of the coin 30 is aligned with the center of the coils 10, 20, ie when the coin is in the position shown in FIG. As shown in FIG. 2, the small coil 20 is mounted at a relatively high position above the coin rail 70 so that the induced eddy currents flow essentially only through the disc 50 without crossing the bond 90. . Conversely, eddy currents induced by the large coil 10 will again essentially flow only through the ring 40 without crossing the bond 90. Therefore, the eddy current induced in the coin flows concentrically around the center of the coin,
Neither eddy current crosses the bimetallic bond 90. Thus, the measured conductivity is independent of the bond.

The duration and waveform of the voltage pulses that the electrical device applies to the coils 10, 20 can be selected according to the actual application, as will be readily apparent to those skilled in the art. To further increase the accuracy, further advanced coin discriminators use magnetic sensor elements
60, preferably a Hall element. Hall elements 60 are arranged to measure the magnetic permeability of outer ring 40 and inner disk 50 of coin 30. In this way, they have the same electrical properties (eg, conductivity) but different magnetic properties (eg, magnetic permeability)
Coins can be identified.

The coils 10, 20 are driven to generate respective magnetic fields, and the outer ring 40 and the inner disk 50 receive this magnetic field. Depending on the magnetic properties of ring 40 and disk 50, the magnetic field is affected to varying degrees. The Hall element measures the magnitude of the magnetic field generated by the coil. The magnitude of the magnetic field from the large coil 10 is bimetallic
4 shows the magnetic permeability of the outer ring of the coin 30. Similarly, the smaller coil 20 has an inner disk 50
Is measured. In the preferred embodiment, some form of multiplexing must be used, either frequency division multiplexing or time division multiplexing, since two measurements are taken from the Hall elements.

In frequency division multiplexing, the large and small coils are driven by sine waves of different frequencies. For a typical coin, 9 kHz and 7 kHz frequencies would be appropriate. The output from the Hall element is a waveform containing both frequencies. With appropriate electronics, for example synchronous detection, the amplitude of the two frequencies can be measured.

In the case of the time division multiplex system, only one coil is driven at a time. For example, the small coil 20 is first driven to measure the output of the Hall element. Thereafter, the second measurement can be performed from the Hall element by driving the large coil 10. The result is the same regardless of which multiplexing scheme is used. It is not necessary that the coin be exactly concentric with the coil for permeability measurements.

For some applications, it may be sufficient to measure the magnetic permeability of one of the outer ring and the center disk of the bimetallic coin. Referring to FIG. 3, a coin processing machine 100 according to one embodiment of the present invention is illustrated. By way of example, and not limitation, the coin processor 100 of FIG. 3 is a coin sorter. A group of coins to be sorted by the processing machine 100 is inserted into the coin entrance 110. The coins are sent by a coin feeder 120, such as a hopper and / or an endless belt, to the coin identifier 130 described above with reference to FIGS. The coin identifier 130 is functionally a logical device 1 in the form of a CPU.
Connected to 32, the logic device is functionally connected to a memory 134 such as RAM, ROM, EEPROM or flash memory. Memory 134 stores a set of coin reference data, and logic 132 uses this data to identify coins received from coin entry 110. More specifically, the coin reference data is data on typical values of conductivity and permeability for any type of coin that the coin processor 100 can process.

The logic unit 132 is programmed to receive measurement data obtained from the coils 10, 20 and the magnetic sensor element 60. The data relate to the conductivity of the outer ring 40 and the inner disk 50, respectively, and the magnetic permeability of at least one of the outer ring and the inner disk. Upon receiving the above-described measurement data for the coin 30, the logic device 132 reads the coin reference data stored in the memory 134 and searches for a match. If both the conductivity and the magnetic permeability measured by the coin identifier 130 correspond to a particular coin type defined by the coin reference data, then this coin 130 type is positively identified. Otherwise, the coin 30 is of an unknown type and is processed by the coin rejection device 140.
The coin reject device preferably sends coins out of an external opening of machine 100 so that the user can remove the coins.

The coin types defined by the coin reference data in the memory 134 preferably relate to the denomination of each coin type to be processed by the coin processor 100. Once the type or identity of the coin 30 is determined by the coin discriminator 130 and the logic unit 132, the coin 30 is sent to the coin classifier 150, which uses the identified coin type to coin the coin. The storage unit 160 is classified into a specific coin box or the like. The coin box or the like of the coin storage 160 is preferably externally accessible to the user of the machine 100.

While the invention has been described above with reference to a few embodiments, other embodiments than the above described are within the scope of the invention as defined by the appended independent claims. It is possible.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a coin discriminator according to one embodiment of the present invention.

FIG. 2 is a schematic side view of the arrangement of FIG.

FIG. 3 is a schematic block diagram of a coin processor according to one aspect of the present invention.

[Procedure amendment]

[Submission date] June 19, 2001 (2001.6.19)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN , IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZA, ZWF term (reference) 3E001 AA01 AB03 AB06 BA01 BA10 CA04 CA05 CA07 CA08 EA09 FA07 3E002 AA13 AA14 AA20 BB09 BC02 BC08 BC09 CA02 CA06 CA08 CA15 DA02 EA03 EA05

Claims (12)

[Claims] A first and second coil (10, 20) arranged to induce and detect eddy currents in an outer ring (40) and an inner disk (50) of a bimetallic coin (30), respectively. A storage device (134) for storing coin reference data; and determining the identity of the coin by comparing the coin reference data with data relating to the conductivity of the coin obtained from the detected eddy current. A logic device (132) suitable for: a magnetic sensor (60) coupled to said logic device (132), wherein said coin (30) comprises said first and second coils and said magnetic sensor And a magnetic field generated by at least one of the first and second coils (10, 20). Location (132), the coin (30)
A coin discriminating device using data on the magnetic permeability of the coin obtained by the magnetic sensor when determining the identity of the coin. 2. The coin identification device according to claim 1, wherein said magnetic sensor is a Hall element. 3. The magnetic sensor (60) is arranged to detect respective magnetic fields generated by a first coil (10) and a second coil (20).
Or the coin identification device according to 2. 4. The coin identification device according to claim 1, wherein the second coil (20) is arranged inside the first coil (10). 5. An outer ring (40) and an inner disk (50), respectively,
) Alone, and measuring the eddy currents induced in this way to determine the conductivity of the outer ring and the inner disk, respectively, and to identify the coin (30) with the outer ring, respectively. And by using the conductivity of the inner disk, a bimetallic coin having the outer ring and the inner disk (
Exposing the coin (30) to a magnetic field; measuring a magnetic permeability of at least one of the outer ring (40) and the inner disk (50); Using magnetic permeability when identifying coins (30). 6. The method according to claim 5, wherein the outer ring receives a first magnetic field and the inner disk receives a second magnetic field. 7. The method according to claim 5, wherein the magnitude of each magnetic field varies. 8. The method according to claim 5, wherein each magnetic field varies as a sine wave. 9. The step of exposing to a magnetic field, measuring the magnetic permeability and using is performed on the outer ring (40) at a first frequency of the first magnetic field, wherein the inner disk (50) 9. A method according to claim 7 or claim 8, wherein the method is performed at a second frequency of the second magnetic field. 10. The method of claim 9, wherein said first frequency is about 9 kHz. 11. The method according to claim 9, wherein the second frequency is about 7 kHz. 12. A coin processor comprising a coin inlet (110), a coin feeder (120), a coin discriminator (130) and a coin processor (150), wherein said coin discriminator is coupled to said coin processor, In a coin processor suitable for determining the type, identity or denomination of each coin (30) received from said coin feeder, and supplying the determined type, identity or denomination to a coin processor. , The coin discriminator (13
0) is the outer ring (40) and inner disc (40) of the bimetallic coin (30) respectively.
First and second coils (50) arranged to induce and detect eddy currents in (50)
A magnetic sensor, wherein when the coin (30) is positioned between the first and second coils and the magnetic sensor, the first and second coils (10, 20) A magnetic sensor arranged to detect a magnetic field generated by at least one of
A storage device (134) for storing coin reference data; data relating to the conductivity of the coin obtained from the detected eddy current; and data relating to the magnetic permeability of the coin obtained from the magnetic sensor; A logic device (132) for determining the identity of the coin by comparing it with coin reference data.