FI65501C - ANORDINATION FOR IDENTIFICATION AV MYNT ELLER LIKNANDE - Google Patents

Description

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Patents registered .............

_ '. (44) Date of issue and of publication. -

Patent- OCh registerstyrelsen '' Antöktn titled och utl. »Krlft.n publteanul 31.01.81+ (32) (33) (31) Pyydttty atuolkau» - BagirS prlorltat (71) Cointest Oy, Höyläämötie l8, 003Ö0 Helsinki 38, Suomi- The present invention relates to a coin or similar device for the identification of coins and the like. The present invention relates to a device according to the preamble of claim 1. device for examining and identifying electrically conductive coins or the like.

Previously known systems for distinguishing coins from each other based on their electromagnetic properties (e.g., GB 1,397-83 and U.S. Pat. No. 3,952,851) generally utilize changes in the frequency and / or amplitude of a freely oscillating oscillator in the vicinity of the coil associated with the oscillator. These methods use stored reference values fixed to the circuits of the device, to which the measurement results obtained from the oscillator using different measurement methods are compared. Thus, the measurements must be very stable with respect to changes in time and western temperature, which is why various temperature and other compensation connections have had to be connected to the circuit technology of several devices.

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Previously known methods generally use one or two sinusoidal measuring signals, the changes of which are often monitored by a special sensor or the like when the coin arrives in the vicinity of the measuring coil or coils.

The system described in GB 1170417 uses a Wheat-Stone bridge to compare the voltage produced by two coils whose magnetic field is affected by a coin with the voltage produced by two voltage divisions formed by a fixed resistor. The solution is characterized by the fact that it cannot be used to form more than one connection that simultaneously measures the reference money, because if branches are added to the Wheatstone bridge connection other than between the energy supply points, they have an interaction.

DE-A-2 029 751 and DE-A-2 034 426 describe an arrangement in which the coin to be measured and the reference coin are located in the same symmetrically arranged transformer in which a magnetic field generated by a single primary coil is measured at two symmetrically arranged locations, where if the coin and reference coin are identical , perfect symmetry is achieved and the measurement signal is attenuated to zero.

However, it is not possible to compare the coin with several reference coins at the same time with the solutions according to the reference publications, which is often necessary in modern coin identifiers.

The object of the present invention is to eliminate this drawback and to provide a device by means of which a coin can be compared quickly and simultaneously with several reference coins.

This object can be achieved by a device according to the invention, which is mainly characterized by what is stated in the characterizing part of the claim.

The advantage of the method according to the invention is the considerable simplicity of the circuit technology used, which is due to the fact that the method does not use reference memory or reference circuits, but the reference values are obtained from a reference coin and the comparison takes place in a coil arrangement during measurements. Circuit technology is also simplified by the fact that the requirements for the measurement signal and measurement system required in the method allow the use of simple connections, because inaccuracies in the measurement signal or measurement connections do not affect the 3 65501 method, as these inaccuracies are corrected in magnetic bridge. In addition, the method used does not require initialization of the measurements due to the continuous measurement. The method also makes it possible to identify coins as they pass one after the other. Since an arbitrary waveform can be used in the measurement signal, its frequency spectrum can be selected as desired, allowing its coin identification to take into account its magnetic properties at several different frequencies. Since the information on the characteristics of the acceptable coin is obtained from the reference coin to be used, the same device can be set to accept any coin by setting a similar coin as the reference coin.

The invention will now be examined in more detail by means of embodiment instructions according to the accompanying drawings.

Figure 1 schematically shows one device used in a known method.

Fig. 2 shows a bridge connection used in the device according to Fig. 1.

Figure 3 shows a bridge connection according to the invention.

Figure k shows a money channel arrangement used in a device according to the invention.

Fig. 5 shows a coil arrangement used in the device according to Fig. 3.

In the following description, the term coin is used to mean coins, tokens, tokens or other possible objects that can be used or attempted to be used in coin-operated devices.

The device according to the invention operates, for example, using the three-coil magnetic bridge connection according to Fig. 3 and the mechanics and circuit technology according to Figs. 1 and M. The coin 1 to be examined is dropped into the device through the mouthpiece 7 into the money channel 5 · The money channel 3 is shaped so that its depth is slightly greater than the thickness of the thickest coin to be examined. The money channel 5 is covered by a cover plate 8. The money channel 5 passes through a group of coils so that the coin 1 to be examined rolls along an inclined plane 6 between the first transmitter coil 101 and the receiver coil 201. A reference coin 2 is placed between the second receiver coil 201 and the transmitter coil 102, whereby the coin 1 to be measured is in a position symmetrical with the reference coin 2 with respect to the circumferential axis a-a passing through the coils 101, 201, 102 (Fig. 2).

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The square wave oscillator 11 feeds the signal through both transmitter coils 101, 102 so that the coils generate opposite magnetic fields at the receiver coil 201, unless there are coins in the system. If there is now no coin in the money channel 5 or the coin in the channel does not have the same electromagnetic properties as the reference coin 2 installed in place, a signal induced by the magnetic field acting on the receiver coil 201 is obtained. However, if a coin 1 to be measured passes in the money channel 5 and is identical in electromagnetic characteristics to the reference coin 2 used, the bridge connection formed by the magnetic couplings of the coils 101, 201, 102 is momentarily balanced as the coin 1 passes between the coils 101 and 201. In this case, the signal received by the receiver coil 201 is momentarily completely attenuated.

The signal from the receiver coil 201 is monitored by an amplifier 21, a rectifier 22, an integrator 23 and a level detector 24 so that when the signal is sufficiently attenuated long enough, the level detector 24 informs the pulse of a monostable multivibrator 25 controlling the solenoid 26 '(Fig. 1). The time constant of the monostable multivibrator 25 is selected so that the control flag 3 operated by the solenoid 26 directs the coin passing in the money channel 5 to the accepted money channel 4 (Fig. 4). Thus, only coins 1 that are identical to the reference coin 2 in terms of their magnetic properties, i.e. material and dimensions, with the desired accuracy, enter the channel 4 of accepted coins.

The coil construction used in the above operation model can also be replaced by a coil construction in which the transmitter and receiver coil form an identification element dO and another similar coil pair reference element 50 (Fig. 3). · By adding reference elements 50a, the coin selector can identify several different coins.

The above coil elements can also be replaced by such coil elements 41, 51 (Fig. 5) in which one coil 301, 302 acts as both a transmitter and a receiver.

The device can also be constructed in such a way that when the magnetic bridge is unbalanced, its measuring current is reduced and when the unbalance state changes towards the equilibrium state, the measuring current increases to its normal value.

Claims (1)

An apparatus for examining and identifying electrically conductive coins (1) or the like, the apparatus comprising an identification unit comprising a first transmitter coil (101) for generating a measuring magnetic field and a first receiving coil (201), at least two reference units each comprising a second transmitter coil (102). 102a) for generating a reference magnetic field which is preferably equal to the measuring magnetic field, and a second receiving coil (202, 202a), , and - preselected reference coins (2), one for each reference magnetic field, which reference coins are preferably identical to the identifiable coins (1), characterized in that - the first transmitter coil (101) and each second transmitter coil (102, 1) 02a) and the first receiving coil (201) and each second receiving coil (202, 202a), respectively, are connected to each other by a magnetic bridge connection for comparison, and - the transmitter coils (101, 102, 102a) are substantially identical and connected in series.