Discriminator for bimetallic coins

Technical area

The present invention relates to a coin discriminator, comprising: a coin path, along which a coin, which includes a first and a second part, which from different Metals and / or metal alloys are made for running past is established; adjacent the coin path arranged coil means; electrical Announcement for feeding time-varying drive signals to the coil means; and recognition means for recognizing in the coin by the coil means induced eddy currents. Furthermore, the present invention relates to a method for Measuring the conductivity at a junction between the first and the second part of such a coin.

description of the prior art

coin discriminator, which to measure the electrical properties, for example, the resistance or conductivity, a coin are set by exposing it to a magnetic pulse and the induced decay in the coin eddy currents recognize are well known in the art. such coin discriminator be in a variety of Münzbedienungsmaschinen used for example in coin counters, coin processing machines, Coin Acceptor for sale and game machine, etc .. Previously known are Münzbedienungsmaschinen for example, disclosed in WO 97/027485 and the WO 87/07742.

The Type in which such coin discriminator work is described for example in GB-A-2135095, in a Münztesteinrichtung comprises a transmitter coil which is pulsed with square-wave voltage pulses is thus to produce a magnetic pulse, which in a passing coin is induced. The eddy currents thus generated in the coin give an increase in a magnetic field, which is monitored or detected by a receiver coil. The receiver coil may by a separate coil or alternatively through the transmitter coil, which two modes has to be formed. By monitoring the decay of the coin induced eddy currents can one for the Münzleitfähigkeit representative value are obtained, since the rate of decay is a function thereof.

The coin discriminator according to the prior art often use a small coil with a diameter smaller than the diameter of the coin. The Coil induces and detects eddy currents in any location the coin (The actual part of the coin, is what the subject of the above conductivity measurement, is dependent on the orientation, speed, angle, etc. of the coin relative to the coil, vary). This approach is adequate for a normal, homogeneous coin, which is made of a single metal or a metal alloy is.

how However, in recent years, bimetallic coins on the market in different countries output. A known example of a bimetallic coin French 10 Francs. Furthermore, some European coin, which within the European Community in the nearby Future output, be as planned by the bimetallic type.

On Discriminator for Bimetallic coins known from EP-B-0639288. The discriminator has features as in the preamble of claims 1 and 8. <figref idrefs="S12">1</figref> EP-B-0639288 shows two sensor coils <figref>12</figref>. <figref>14</figref>Which side by side along the coin path are disposed and wherein the signals from the coils in a bridge circuit are used to discriminate bimetallic coins.

Bimetallic coins be prepared as follows. Outer rings and central discs are made of metal sheets from (also known as Münzplatte) the two metals or metal alloys punched, from which the bimetal coin is made. The disc is then fitted into the ring, and the coin is embossed. embossing consists of the compressing the coin between two hardened Stamp. The stamp stamp the pattern of the head and the number [Tail] on the coin and force also the disk and the ring together. The connection between the disk and the ring is called a covenant [bond].

If the disk and the ring are clean and free of oxides, has the Covenant between the metals almost no electrical resistance. Ideally, the resistance of the metals or alloys is much greater than the resistance across the covenant. Anyway, if the ring or disc before coinage are covered with an oxide layer, the resistance of the Confederation greater than be the resistance of metals or alloys. Consequently, it is by controlling the treatment and storage of textures coin blanks between the cutting and embossing, possible, to control the connection resistance (or, alternatively, the conductivity, which basically the inverse of the resistor) in the finished bimetallic Coin.

The Controlling the resistance of Verbin&lt;?page 3?&gt;manure in this way may in particular as an anti-fraud measure he wishes be. During production coins with as little or high resistance not output. To such a controlled production to make it applicable, would a A method for repeatedly measuring the connection resistance of a great Amount of coins needed will.

The above described coin discriminator according the prior art fail to provide a sufficiently precise Determination of the Confederation resistance or conductance, since the resulting Measurement results in a large vary extent would, dependent from the actual Location of measurement on the coin. In other words, if the conductivity for a given coin at a located in the ring body would be measured, the measurement results would differ from the results which are obtained if the measurement would be performed on the disc. Furthermore, if the measurement point a portion between the ring and the disk would include, would now a Another measurement results are obtained. A coin discriminator according the prior art is cited in the introductory part of claim 1.

Summary the invention

it is therefore an object of the present invention, repeatable and accurate detection of conductivity or to allow the resistance of the Federation into a coin which a first and a second part, consisting of different metals or metal alloys are made, for example, a bimetallic Coin.

The The aim is achieved by a coin discriminator, comprising: a coin path along which a coin is adapted for passage of; adjacent coil means the coin path; electrical Means for supplying time varying drive signals to the coil means; and recognizing means for recognizing in the coin by the coil means induced eddy currents, by thus arranging the coil means so that an eddy current loop Such a kind of coin is induced to a predetermined region of the coin the Bund crosses between the first and the second part of the coin.

furthermore the above object is achieved by a method for measuring the conductivity the bond between the first and second part of the coin, in the coin one by the outside located coin Magnetic coil means produced is exposed, and wherein in the coin induced eddy currents by detection means external the coin be detected, the magnetic field being generated such that a Loop of eddy currents the covenant crossed in a predetermined region of the coin.

The Solutions described above be defined by the appended independent Claims. Preferred embodiments of the present invention are subject of the dependent claims.

Kure Description tHE dRAWINGS

The Invention will now be described in more detail, reference being made to the accompanying drawings is taken, in which:

<figref idrefs="S12">1</figref> is a schematic section view of a corresponding Münzunterscheiders a preferred embodiment, the invention,

<figref idrefs="S12">2</figref> is a schematic plan view of the device of <figref idrefs="S12">1</figref>. and

<figref idrefs="S12">3</figref> is a schematic illustration of a bimetallic coin and therein by the coin discriminator the <figref idrefs="S12">1</figref> and <figref idrefs="S12">2</figref> eddy currents generated.

Detailed description

how in <figref idrefs="S12">1</figref> shown, the coin discriminator comprises a coil means in the form of two coil parts <figref>1a</figref> and <figref>1b</figref>, Which are connected to an electrical device <figref>7</figref>, Which Voltage pulses fed into those. Furthermore includes the coin discriminator recognition means <figref>9</figref> for detecting eddy currents, which in the coin by the generated by the coil means as magnetic pulses Response to the voltage pulses, which from the electrical means <figref>7</figref> fed were were induced. The coil means<figref>1a</figref>. <figref>1b</figref> Act as a transmitter coil for exposing a bimetallic coin <figref>5</figref>, Which to the coin discriminator along a 1 mm thick ceramic plate <figref>3</figref> in a by an arrow indicated direction is moving past a magnetic Pulse which an increase in eddy currents in the coin <figref>5</figref> causes and continue the coil means act as receiver coils for detecting the magnetic Field changes, which by the eddy currents in the coin <figref>5</figref> generated are, and for converting this corresponding to a voltage signal.

how in <figref idrefs="S12">3</figref> shown, the coin <figref>5</figref> a ring <figref>13a</figref> one first metal or alloy and a disc <figref>13b</figref> out a second metal or alloy. A covenant between the disc<figref>13b</figref> and the ring <figref>13a</figref> is with <figref>11</figref> drawn. The detection device<figref>9</figref> is adapted to measure the decay of these eddy currents and related ser&lt;?page 4?&gt;gen value conductivity or the resistance of the Federal generate in response thereto. As will be described below, the coin discriminator adapted to the conductivity measurements execute, when the center part of the coin <figref>5</figref> with a Central area <figref>21</figref> of Münzunterscheiders is aligned.

how in <figref idrefs="S12">2</figref> to see include the coil means <figref>1a</figref>. <figref>1b</figref> a first and second coil frame <figref>17a</figref>. <figref>17b</figref>. which with a corresponding first and second winding <figref>15a</figref>. <figref>15b</figref> equipped are. The creel<figref>17a</figref>. <figref>17b</figref> have substantially a semi-circular Section shape and are symmetrical on each side of Spulenzentalfläche <figref>21</figref> arranged. The distance between the coil frame <figref>17a</figref> and <figref>17b</figref> is about 5 to 10 mm, and the radius of each semi-circular section is about 10 to 20 mm. An electrical conductor is provided with an equal number of Turns on each coil frame <figref>17a</figref>. <figref>17b</figref> wound. For example, a polyurethane copper wire wrapped with an inner Diameter of 0.2 mm and an external diameter of about 0.25 mm be used as the electrical conductor, which turns the <figref>15a</figref>. <figref>15b</figref> on the creel <figref>17a</figref>. <figref>17b</figref> forms. preferably contains each winding <figref>10</figref> to <figref>100</figref> Windings, and further A winding <figref>15a</figref> wound clockwise, while the other winding <figref>15b</figref> is wound in a counterclockwise direction, from set out below reasons.

The neighboring parts <figref>19a</figref> and <figref>19b</figref> the two halves <figref>1a</figref>. <figref>1b</figref> the Coil contain winding wires, which extend substantially mutually parallel and symmetrically with respect to the coin surface <figref>21</figref> arranged are. Further, since the windings<figref>15a</figref>. <figref>15b</figref> just by a single contiguous Conductors are formed, a common electric current is through the entire windings <figref>15a</figref> and <figref>15b</figref> flow when He by a voltage pulse from the electrical means <figref>7</figref> driven becomes. As a result, a pulsed magnetic field to the windings <figref>15a</figref>. <figref>15b</figref> be generated. In the central Region of the coil, ie the adjacent parts <figref>19a</figref>. <figref>19b</figref> and the central area <figref>21</figref>. is the current in the same direction in the two windings <figref>15a</figref> and <figref>15b</figref> flow and is thus cooperate in generating a magnetic field.

The Bund conductivity is measured when the coin is in the middle of the coil, as in <figref idrefs="S12">1</figref> shown, that is, if the diameter <figref>23</figref> (please refer <figref idrefs="S12">3</figref>) of the coin <figref>5</figref> With the central area <figref>21</figref> the Kitchen sink <figref>1a</figref>. <figref>1b</figref> is aligned. The duration of the voltage pulse, which by electrical means <figref>7</figref> in the coil <figref>1a</figref>. <figref>1b</figref> fed is, may in accordance with the actual selected application will; however, a period of 10 to 100 microseconds appear for most cases appropriate.

thanks the above device is an eddy current loop <figref>27</figref> in the coin <figref>5</figref> along generates a path which is approximately the wire patterns of two windings <figref>15a</figref>. <figref>15b</figref> (Ie the symmetrical double semicircular Form) matches, as shown schematically in <figref idrefs="S12">3</figref> is shown. The exact shape one in a coin Eddy current loop generated is a complex thing, the difficult mathematical is to model. Anyway, tests have shown that a Eddy current loop has a flow which is approximately equal to the one described below is.

The in <figref idrefs="S12">1</figref> and <figref idrefs="S12">2</figref> Coil shown is for use with coins with a smaller diameter than the diameter of the coil <figref>1a</figref>. <figref>1b</figref> provided. As a consequence, in the coin <figref>5</figref> generated Eddy current loop <figref>27</figref> in the <figref idrefs="S12">3</figref> shown have form. In the central region<figref>25</figref> the coin <figref>5</figref>. ie in a region adjacent to the diameter <figref>23</figref> the Coin, is the eddy current loop <figref>27</figref> (Or actually, the two eddy current loops <figref>27</figref>) Parallel to the diameter <figref>23</figref> at a location on one side of the coin to a point on the opposite side of the coin extend. If the eddy current loop<figref>27</figref> the circumference of the coin <figref>5</figref> reached, we forced the eddy current to flow to the coin surface and eventually on the first side of the coin to return. As Result, the eddy current loop <figref>27</figref> the covenant <figref>11</figref> in between the ring <figref>13a</figref> and the disc <figref>13b</figref> the coin <figref>5</figref> twice while the path from the first side of the coin to the opposed Side, that is along the diameter <figref>23</figref> the coin <figref>5</figref>. cross. Consequently, since the measurements take place when the coin<figref>5</figref> With the coil <figref>1a</figref>. <figref>1b</figref> is aligned, the detection is eddy current loop <figref>27</figref> be bound by the covenant <figref>11</figref> With involve, in contrast to the approaches according to the prior art which fail in this respect.

By the use of a Münzunterscheiders according to the present invention, it is possible the risks of forgery reduce because the coin discriminator while the production of coins can be used to make such coins sort out, in which a coil is determined that a Resistance or a conductivity has which outside the predetermined limits falls. Preferably, the coin discriminator is operatively connected to memory means, which are not disclosed in the drawing are, for storing predetermined maximum and minimum values conductivity or the resistance of the connection for the current type of coin. After this conductivity or resistance of the coin was measured, the output of the detection means is <figref>9</figref> With the predetermined limits compared to determine&lt;?page 5?&gt;whether the conductivity or the resistance of the connection within an acceptable range falls, within which the coin is authorized to issue, or whether it is not acceptable within the Area falls in which case the output of the coin is prevented.

correspondingly an alternative embodiment, can the coin discriminator described above used for least points the authenticity of bimetallic coins be, which are already on the market, by detecting the conductivity or the resistance of their federal and comparing a detected Value with predetermined limit values. The invention has been up to Reference to a few embodiments described. Anyway, there are other versions as the above described within the scope of the invention possible, as attached by the independent claims are defined. For example, the coil means by other electrical signals in the voltage pulses be operated, for example, sine wave or square wave. Around the desirable eddy currents in the coin to produce, can be more or less any kind of time varying electrical drive signals are used as easily by the skilled person is detected.

furthermore can the coil means comprise more than two coil frames and windings. For example, could the coil means of 4 frames and windings are formed which preferably arranged symmetrically to each coil central surface (s) are.