Patent Application
20100119865
The present invention relates to novel metallic composites that are suitable as coinage materials for the minting industry. More particularly, the present invention is directed to metallic composites designed for the specific purpose of affecting their electromagnetic properties, in particular their electromagnetic signature (EMS), and includes a method of making coins as well as the coins themselves.
Coins are commonly used as a means of payment in vending or similar automatic machines. In this function, the coin needs to be recognized and identified by the machine and either accepted or rejected. This discrimination process is carried out by a device called a coin acceptor and generally consists of measuring various physical properties of the coin as it move's through the acceptor's mechanism.
Most coin acceptors presently in use rely on signals that result when a coin disturbs a variable electromagnetic field. For example, a coin moves between two coils acting as emitting and receiving antennae, respectively. The signal picked up by the receiving coil is then analyzed using a proprietary algorithm to produce what is called an electromagnetic signature (EMS) of the coin. Based on its EMS, the coin is either accepted or rejected.
A common problem affecting coin acceptors is the fact that electromagnetic signatures (EMSs) may be very similar for different coins. When the EMSs of coins of different denominations or coins issued in different jurisdictions are similar, there is an opportunity for fraud.
As referenced above, EMS values are not calculated by any physical, chemical or mathematical formula. Rather, they are a set of numbers generated by software and algorithms devised by each coin acceptor mechanism manufacturer. EMSs are unit-less and are made up of a set of figures which are purported to determine the diameter, the edge thickness, the weight, the alloy composition, etc., of a coin at different frequencies. Moreover, these values are not single repetitive values which identify the characteristics of the coin. Rather than being exact; the values vary from coin to coin within a certain range. Accordingly, that range is critical for coin acceptor manufacturers, since even perfectly valid coins may be rejected. The range of values must therefore be established so as to properly characterize the specific properties that identify the particular features of a coin, such as its diameter, edge thickness or alloy.
Perhaps one of the best ways to relate an EMS to a known physical measurement is through the metal's conductivity. Commercial instruments are available to measure conductivity, such as the Dr. Foerster's™ Sigma D conductivity meter and the Fischer Sigmascope® SMP10 conductivity meter.
With base metals increasing in price over the last 30 years, people working in the minting industry have come up with ideas on how to reduce the cost of producing coins, including finding metal substitutes for more expensive base metals, such as nickel and copper. Substitutes include mono-ply plated steel products. Mono-ply plated steel consists of plating a single layer of a metal or an alloy over steel. This is to be distinguished from multi-ply plated steel, which consists of plating several layers on steel.
Sample patent applications and patents that describe mono-ply plated steel include the following: Canadian Patent Application No. 2,137,096, Canadian Patent No. 2,271,654, U.S. Pat. No. 4,089,753, U.S. Pat. No. 4,247,374 and U.S. Pat. No. 4,279,968. Alternatives include coins in which the core is made of a metal, such as nickel or copper, which is mono-ply plated with either another metal or an alloy. Sample patents of this type include United States Patent No. 3,753,669, U.S. Pat. No. 4,330,599 and U.S. Pat. No. 4,599,270.
Inconveniently, coin acceptor mechanisms in the vending industry often cannot differentiate between coins from different countries that are made of the same alloy and have approximately the same diameter, thickness and weight. In addition, mono-ply plated steel coins have EMSs that are so variable and so close to that of steel that many vending machines cannot be calibrated to differentiate between regular steel and mono-ply plated steel.
Metal disks, especially coins, have been produced so as to be distinguishable and separable from one another on the basis of their magnetic properties. As proposed by German Patent Application DE 3207822 and U.S. Pat. No. 3,634,890, laminate metallic claddings suitable for coin production include magnetizable metals (such as nickel) as well as non-magnetizable metals (such as a copper-nickel alloy containing 5 to 60 percent nickel). Along the same lines, U.S. Pat. No. 4,973,524 describes a method of making coins that are a suitable as an alternative to nickel-containing coins, the method comprising the steps of forming a laminated composite comprising a core layer of a first corrosion-resistant steel, such as ferritic-chromium steel, and cladding layers on opposite sides of this core layer with a second corrosion-resistant steel, such as austenitic nickel-chromium steel.
Despite the above, counterfeiters are actively finding ways to get past the electronic devices used in vending machines, and therefore fraud continues to be a major problem. There thus remains a need for novel coins that combine metals that are favored by manufacturers of legal tender but that may be discriminated on the basis of their EMSs.
The present invention seeks to meet this and related needs.
The shortcomings associated with current coin technology can result in a breach of security and revenue when vending machines cannot distinguish coins from two different countries, or when the vending machines cannot differentiate between a mono-plated steel coin and a steel slug. In order not to jeopardize the vending machine industry, many coin acceptors simply do not accept any mono-ply plated steel coins.
The present invention provides an alternative to coinage materials that are currently available. Specifically, the present invention relates to novel multi-ply metallic composites and their use in the manufacture of coins.
On the condition that one or more of the plated layers is/are non-magnetic if the core is steel or made of another magnetic material such as nickel, or on the condition that the plated layer is of a magnetic material if the core is non-magnetic, the intensity of the induced current can be modulated through the control of the thickness of the layers of the paired combination of magnetic and non-magnetic materials in such a way that the coin will generate totally different induced current features. This permits coin acceptor mechanisms to differentiate, recognize and identify coins as being different, even though they may have the same or a very similar diameter, thickness and weight. The ability to discriminate two coins having the same physical features even though they have different designs is a unique and very powerful tool to control the misuse of coins of one country in another country. Unlike human beings, coin acceptor mechanisms in their present technological state do not look at the visual or graphical features of coins to identify them. As indicated above, acceptor mechanisms work on current waveform data and defined feature points.
It has been found that by judiciously choosing the type of metals deposited through electrogalvanic (plating), and by manipulating the plating deposit thicknesses of the metal layers, the type of induced current generated by a coin can be modulated. If one or more of the plated layers are non-magnetic, and the core is made of a magnetic material such as steel or nickel, the intensity of the induced current can be modulated. Alternatively, if one or more layers are magnetic, and the core is made of a non-magnetic material, such as copper, zinc, tin, aluminum, silver, gold, indium, brass or bronze, the intensity of the induced current can also be modulated. Specifically, by controlling the thickness of the layers of the paired combination of magnetic and non-magnetic materials, the coin will generate completely different induced currents, which in turn allow coin acceptor mechanisms to distinguish coins even though they may have the same diameter, thickness and either an identical or similar weight.
Single layer plating, particularly with metals having magnetic properties, such as nickel and cobalt, was found to have inherent limitations that render manipulation of the EMS of a coin difficult, even by modifying such features as the coin's thickness.
With all of the above in mind, the present invention provides:
Other objects, advantages and features of the present invention will become apparent upon reading of the following non-restrictive description of embodiments thereof, given by way of example only with reference to the accompanying drawings.
All coin acceptors are designed to work on the induction principle. A coin acceptor is designed to have live coils (sensors) under power at 2 or 3 different frequencies (normally, 2 frequencies, high (240 KHz and higher) and low (60 KHz and lower)). The coils are sufficiently removed from each other so that no significant current is picked up by a current analyser connected to the live coils.
When a coin is dropped into a coin acceptor, the (space) gap between the coins is quickly and temporarily closed and a current is induced as the coin goes past the coils (sensors). The inductance of the sensors combined with the eddy current in the coin generates two (2) sinusoidal electric currents, due to two (2) different sets of coils at two (2) different frequencies.
The current analyser combines the 2 currents, which are then analysed at various points which are identified as EMS signals.
The captured EMSs are analysed with proprietary algorithms specific to each coin acceptor model and brand. The EMSs are converted to data identified as parameters.
The EMSs are dependent on the size (diameter), mass (edge thickness and weight) and type of metals (or alloys) used to make the coins.
Accordingly, coins of the same alloy and approximately of the same diameter cannot be differentiated by the coin acceptors. For example, the US five (5) cent coin and the Canadian five (5) cent coin (dated prior to 1999) are both made of cupronickel (75% copper 25% nickel) and cannot be differentiated by the existing coin acceptors in the market.
The shortcomings of today's coin recognition and discrimination technology can have serious consequences for the economy of a country. In the case of the US (5) cent and the Canadian (5) cent coins, the problem is accepted because their face values are approximately the same. For other countries, however, the economical ramifications can be very serious if their exchange rates are far apart, because if the coins of two countries are exactly or almost of the same diameter, size, thickness, weight and/or same alloy, they can be used interchangeably in vending machines. This opens the door to fraud and counterfeiting, because vending machine sensors do not rely on the pictorial or visual designs to recognize and to differentiate the coins.
The object of this invention is the creation of metallic composites that are suitable for coin production. The resulting coinage products are unique since they help to eliminate the problems associated with look-alike coins which have plagued many European, North American and Asian economies. Many nations have a broad base of automated merchandising services that rely in the use of coins, including automatic candy machines, sandwich machines, telephones, soft drink dispensers, coffee machines, public or common transit services, parking meters, road tolls, casinos and gaming machines. The novel coins of the present invention should be useful for such services.
Since coin acceptors have different means and ways of capturing and recording the EMSs, the best way to illustrate and to explain the concept is to relate the metallic characteristics to its current conductivity measured in IACS % (international annealed copper standard percentage).
The difference between single layer blanks and RCM Multi-layer Blanks is shown in
Returning now to
In comparison, the EMS of a mono-layer of nickel on steel at 60 KHz gravitates around 110% IACS, which is the approximate EMS of steel. The range of values reflects the strong magnetic nature of steel and nickel. Practically speaking, the variations associated with mono-layer products are too numerous to be considered usable by vending machine manufacturers to calibrate coin acceptors. In addition, steel cannot be considered as a coinage material for the following reasons: it rusts, it is a very common material and if a coin is made of steel only, it may be readily counterfeited by anyone equipped to cut a steel disc of the correct size.
As indicated above, steel and nickel are magnetic, and nickel plated steel is also magnetic. In order to make a metal alloy less magnetic and in order to give it a more stable EMS signal so that it can be used in the ranges devised by vending machine manufacturers for calibration, one has to stabilize the EMS value within a narrow range desired by the vending industry.
A plated material that can substantially affect the electrical current conductivity of a coin and that can be changed by modifying the thickness of material provides means for controlling and varying the conductivity, and therefore, the EMSs of coins. Furthermore, if a metal can negate the effects of magnetism, the levels of magnetism can be varied and therefore EMS values can be modulated.
Pure copper is very conductive, offers very low resistance to electrical current flow and is non magnetic. Other metals or alloys which can be considered for the production of coins are, without limitation, aluminum, zinc, tin, silver, gold, indium, brass and bronze.
When a non-magnetic metal is plated over steel, the overall magnetic value of the paired “non-magnetic metal—steel” combination can be altered. This is an important consideration for the modulation of the magnetic intensity of a metallic composite, allowing flexibility in changing the EMS values of the metals formed. Moreover, by varying the thickness of the deposit of the non-magnetic metal layer over steel, various degrees of magnetism can be imparted to the combined non-magnetic—steel pair. These significant discoveries can serve as a powerful tool in the control of the EMS values of coins and hence, in the prevention of fraud.
In addition, the degree of electrical conductivity can significantly influence the intensity of the electrical current going through the non-magnetic-steel pair. In other words, the EMS of coins can be controlled through the judicious selection of the thickness of the metals or alloys, or combination of metals or alloys, deposited on steel. For example, by combining metals such as copper, nickel and steel, the magnetic properties and electrical conductivity of these metals can be advantageously combined to change the EMS of the resulting coins in order to give to each type of coin a range of specific values which can be used by coin acceptors to recognize, differentiate, discriminate and ultimately, to either accept or reject the coins.
To illustrate the control that can be exerted on the electromagnetic signals of coins of the present invention, a series of plating experiments were conducted. Different thicknesses of deposits of nickel and copper, in alternate layers, on steel blanks were made. The conductivity of the combined effect of the layers of nickel and copper at different frequencies was measured, and different results were obtained, as anticipated.
Each layer exerts a certain influence on the EMS of the coins. Different metals have different influences. Tests have shown that changes in the thickness of the copper layer appear to affect the EMS the most.
The trend of the electrical conductivity change is very clear from
In another set of experiments, the EMS values of a large number of coins were recorded. These coins, which were plated by a multi-ply plating process such as that described in Canadian Patent No. 2,019,568 (Truong et al.), were allowed to pass through a commercial coin sorter, Scan Coin 4000 (
The internal nickel layer is fairly constant at 6 microns and the external nickel layer is approximately between 10 and 11.5 microns. The copper layer varies between 4 to 24 microns.
In another series of experiments, three (3) different types of blanks were plated with the following arrangements of plating thickness conditions:
The blanks were minted into coins and the coins were passed through the commercial ScanCoin coin sorter, model 4000, which measures the coin conductivity.
It should be noted that, for all practical purposes, the differences in the weights of the 3 coins are not perceptible because a difference of a few microns of copper is of the order of 0.005 g to 0.01 g.
This invention thus provides a very powerful tool to change the EMS of coins. It is quite unique since the process makes it possible to alter the electrical conductivity of metallic coins which is not possible with conventional metallurgical alloys.
The practical uses of this invention are enormous since this method provides means to alter the physical and electrical properties of coins without having to substantially change alloy compositions. The process is unique, very economical and provides an excellent method to create different electromagnetic signals for coin differentiation which is not possible by other means.
Each alloy has its own EMS. A small change in alloy composition over 1 percent does not change the EMS of the alloy. In multi-ply electroplating, it is possible to change the EMS of the metal product significantly by making a judicious change of the order of a few microns in the copper layer deposit which represents a change of less than 0.005 percent of the weight of the coin.
This concept applies to a deposit of 2 or more layers of metals, at least one of which is non magnetic, such as copper, zinc, tin, aluminum, silver, gold, indium, brass or bronze.
The above-described embodiments of the invention are intended to be examples only. Variations, alterations and modifications can be made to the particular embodiments described herein by those of skill in the art without departing from the scope of the invention, as defined in the appended claims.
The present patent application claims the priority of U.S. Patent Application No. 61/061,287 filed Jun. 13, 2008, which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61061287 | Jun 2008 | US |
