CA1330229C

CA1330229C - Method and apparatus for checking coins

Info

Publication number: CA1330229C
Application number: CA000579409A
Authority: CA
Inventors: Siegfried Seiler
Original assignee: Wh Munzprufer Dietmar Trenner GmbH
Current assignee: Walter Hanke Mechanische Werkstaetten GmbH and Co KG
Priority date: 1987-10-06
Filing date: 1988-10-05
Publication date: 1994-06-14
Anticipated expiration: 2011-06-14
Also published as: EP0311554A2; EP0311554B1; DE3889190D1; EP0311554A3; ES2050719T3; ATE104781T1; DE3734114A1

Abstract

ABSTRACT

METHOD AND APPARATUS FOR CHECKING COINS

A method and an apparatus for checking coins are proposed, in which thecoin is guided in a coin channel, the coin edge is irradiated and the reflected radiation detected. By means of a slit or the like, the coin edge is irradiated and scanned in strip-like manner at right angles to the coin channel in such a way that the reflection differences occurring when there are grooves on the coin edge are supplied in the form of an a.c.
signal.

Description

1 3302~Y

METHOD AND APPARATUS FOR CHECKING COINS
' The invention relates to a method and apparatus for checking coins.

~: A criterion as to whether coins are genuine or admissible for coin-operated machines is constituted by their edges, which can be smooth, grooved or have other impressions.
The prior art discloses numerous different groove checking means for coins. DE-OS 28 25 094 describes a method and an apparatus for checking the milled edge of coins, in which the coin track or path has a vibratable section or with it is associated a vibratable element, which can be engaged with the edge of a coin, the vibrations of the vibratable ~` element being detected and converted into an electric ;~ signal.

This construction suffers from the disadvantage that as a result of mechanical action by introducing wires or strips through the coin insertion slit the vibratable elements can ~ be bent, so that they become completely ineffective or give `~ an incorrect result. -In addition, reflection measurements of the edge surface of ;~
the coin are known for the purpose of checking the latter.
The degree of reflection is reduced when grooves are -~
present, so that the signal supplied by the receiver is !
reduced. This type of checking suffers from the disadvantage that the general brightness of the edge of the coin, i.e. the complete reflected radiation of the coin is detected, so that worn or polished grooves can be detected -~ -' ~:

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- la -as smooth coins and scratched, smooth coins can be detected as grooved coins. Darkened coins can also be interpreted as grooved coins.

The problem of the invention is therefore to provide a method and an apparatus for checking coins enabling the ;~
presence of grooves to be unambiguously detected, so that ~b~
a completely satisfactory checking on the basis of different grooves is ensured.

In accordance with an embodiment of the present invention there is provided in a method of verifying coins, wherein a given coin travels in a coin channel, the edge of the ~`~
coin is irradiated and the reflected radiation detected, -~
the improvement comprising: irradiating the edge of a coin in a strip-like manner at about right angles to the ` i direction of coin movement; scanning the radiation ~ -reflected on the edge of a coin in a strip-like manner at about right angles to the coin direction of coin movement;
generating an a.c. signal when grooves are detected on a coin edge; converting the a.c. signal into pulses; counting ~ `
the pulses; and comparing the number of pulses with a predetermined value based on a standard comparison value for coins.

In accordance with another embodiment of the present invention there is provided an apparatus for verifying coins including a coin channel adapted to receive coins, a ~i radiation source adapted to irradiate an edge of the coin and a radiation receiver for detecting the radiation ` C ,~
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- lb -reflected on the coin edge, the improvement comprising: at least one slit located at about right angles to the coin channel, the radiation source and the radiation receiver being arranged behind the slit, means for generating an a.c. signal responsive to the presence of grooves on a coin edge, means for converting the a.c. signal into pulses, and means ~or comparing the number of pulses with a predetermined value based on a standard comparison value for coins. ~ ~
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In greater detail, through the provision of one or more narrow slits in the coin channel ..
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` - ~` 1 330229 thrcugh which the moving past coin is irradia-ted and/or through which the radiation reflected by -the coin is scanned, no longer is the entire reElec-tion of the complete irradiated coin edye detected and instead the individual grooves of a grooved coin are detected, because ra~iation and -scanning only takes place with respect to narrow regions of the coin edge corresponding to the width of the groove or the spacing of the grooves.
Thus, the radiation receiver supplies an a.c. signal, which is a measure ~ -of the number of grooves per detected path or distance unit. As a path or distance scan is carried out, i.e. a scan of the number of grooves per distance unit, there is no time dependence, so that the method can be performed slcwly or rapidly.

Advantageous further develcpnents or improvements are possible through the -~
measures given in the subclaims. An embodiment of the invention is described in greater detail hereinafter relative to the drawings, wherein show:

Fig. 1 A view of the coin channel of a coin checking means with the inventive apparatus.

Fig. 2 An evaluating circuit connected to the receiver according to the invention.

In fig. 1 1 is the coin insertion slit, which passes into the sloping coin channel 2. Over at least part of the width of the coin channel 2 at the base thereof is provided an illumination window 3, which can be covered with a transparent material. A radiation source 4, e.g. a light emitting diode irradiating in the infrared radiation range is positioned beneath the illumination window 3. Adjacent to the illumination window in the base region at right angles to the coin channel 2 a scanning slit 5 is provided over part of its width and behind which is provided a receiver 6, which can be constructed as a photodiode or a phototransistor.

m e scanning slit 5 can be differently constructed, e.g. it can be fonmsd by a narrcw fibre glass line leading to the receiver 6. It is also possibe to prcvide narrow diaphragms or the likeO which terminate in the bottom of ~-3 - 1 330229 the cQin ch2nnel 2 and cQnd~lct the ra~iaticn -to receiver 6. Radiation sGurce 4 and receiver 6 can also be lQcated in a plastic bcdy, the scanning slit S being cut into said bcdy. In another e~bcdiment the receiver 6 is pointed in wedge-like manner, so that a slit-like receiver suxface is obtained.

In the represented em~odiment the radiation scurce 4 has a larger illumin-ation windcw 3, whilst the receiver 6 is positioned behind the narrow slit 5.

The invention can also be real1 ed in such a way that the radiation source 4 irradiates the mQving past coin 13In strip-like manner through a narrcw slit and the ra iation receiver 6 receives by means of a wider windcw the radiation reflecte~ on coin 13as a result of the strip-liXe irradiation.
ObviGusly, a narrcw slit can be provide-~ both for the radiation source 4 and for the radiation receiver 6.

Fig. 2 shcws an evaluating circuit for the signal supplied by the radiation ~ , receiver 6. The radiation receiver 6 constructed as a phototransistor or photoliode is connected to a two-stage, lcw pass (filter) feedback -amplifier 7, the individual amplifier stages 8, 9 being interconnected by means of a high pass filter 10. To the output of amplifier 7 is connected for pulse shaping pu~poses a Schmitt trigger 11, which is connected to a programmable counter 12 or a microprocessor;
.
After insertion into the slit the coin 13 in coin cha~nel 2 rolls up to the ra~iation source 4 and past the r~diation receiver or scanning slit 5 and as frcn a specific position with respect to the lllumlnation windcw 3 the edge of the coin is irradiate~. Via the scanning slit 5 the radiation reflected on the edge of coin 13 passes to receiver 6 and in each case only -a narrow strip-like region at right angles to the mcvement direction of coin 13 is detected. If the edge of coin 13 is provided with grooves, as a function of the particular groove there is a change to the de~ree of reflection, so that at the output of receiver 6 is app~ie~ a signal with an a.c. voltage component. The amplifier 7 aTplifies the high frequency a.c. voltage, whilst ~he low frequencies undergo feedback acI~ss the particular resistor. The Schmitt trigger 11 converts the a.c. voltage ~' ~ 4 l 3~0229 signal into digital signals, each pulse corresponding to a groove. Thus, this arrangement makes it possible to quantify the reflection di~erence on the coin edge surface. The digital signal supplied by the Schmitt trigger 11 is supplied to the programmable counter 12 and its reading is increased for each pulse. The characteristic quantities associated with ~;~
the different coins and which correspond to a specific number of grooves per path and/or time unit, are fixed as predetenmined counter readings ;~
which can be programmed in in a fixed manner. Thus, radiation source 4, receiver 6 and the evaluating circuit establish the number o~ grooves and compares same with a predetermuned number, so that it is possible to es~ablish whether the coin to be checked i5 a pernittea coin or not. The represented embodiment makes use of a programmable counter 12. However, it is obviously possible to use a microprocessor for evaluating the signal supplied bv the Schmitt txigger 11.

If a smooth coin is detected by the receiver, no a.c. signal is to be expected, so that the end of the check must have been reached. Thus, e.g.
the tlme which a coin is expected to take for its path in the coin channel is predetermined and is used as a measure for the end of the check.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a method of verifying coins, wherein a given coin travels in a coin channel, the edge of the coin is irradiated and the reflected radiation detected, the improvement comprising:
irradiating the edge of a coin in a strip-like manner at about right angles to the direction of coin movement in a coin channel having a base in which the base has a slit therein; scanning the radiation reflected on the edge of a coin in a strip-like manner through the slit at about right angles to the coin direction of coin movement; generating an a.c. signal when grooves are detected on a coin edge; receiving, through a receiver in said base, and converting, said a.c. signal into pulses; counting said pulses; and comparing the number of pulses with a predetermined value based on a standard comparison value for coins.

2. A method as defined in claim 1, including the step of filtering said a.c. signal from a main signal including said a.c.
signal.

3. In an apparatus for verifying coins including a coin channel having a base, said coin channel adapted to receive coins, a radiation source adapted to irradiate an edge of the coin and a radiation receiver for detecting the radiation reflected on the coin edge, the improvement comprising at least one slit located at about right angles to said coin channel in said base of said channel, said radiation source and said radiation receiver being arranged behind said slit and in said base of said channel, means for generating an a.c. signal responsive to the presence of grooves on a coin edge, and means for converting said a.c. signal into pulses, and means for comparing the number of pulses with a predetermined value based on a standard comparison value for coins.

4. An apparatus as defined in claim 3, wherein there is included an evaluation circuit having a counting circuit for detecting pulse signals produced by the grooves of a coin edge and a comparator circuit for comparing the detected signals with a predetermined value, said radiation receiver being operatively connected to said evaluation circuit.

5. An apparatus as defined in claim 4, wherein said evaluation circuit has at least one filter for filtering an a.c. signal from a main signal reflected from a coin edge having grooves.

6. An apparatus as defined in claim 5, wherein said filter is a low pass, feed back amplifier, and wherein said counting and comparator circuit are programmable counters.

7. An apparatus as defined in claim 3, 4 or 5, wherein said slit has a width equal to or less than the distance between the spacing of grooves on a coin edge to be verified.

8. An apparatus as defined in claim 3, 4 or 5, wherein said radiation source and said radiation receiver are housed in a plastic body, said plastic body having a plurality of openings and a scanning slit terminating at one end at a boundary surface of said coin channel and at the other end at said radiation receiver.

9. An apparatus as defined in claim 3, 4 or 5, wherein said slit is filled with a glass fiber material.

10. An apparatus as defined in claim 3, 4 or 5, wherein at least one of said radiation source and said radiation receiver have a slit-like transmitter or receiver surface.

11. An apparatus as defined in claim 3, 4 or 5, wherein a diaphragm is provided between said slit and at least one of said radiation source and said radiation receiver, said diaphragm being adapted to guide radiation generated by said radiation source.