Coin-testing Apparatus

Abstract

A coin tester for vending machines in which the coin to be tested forms a core to concentrate the magnetic flux between a first coil provided with a constant voltage AC current, and a second testing or measuring coil in which an EMF is to be induced whereby deviations of the magnetic properties of a coin being tested from the magnetic properties of an acceptable coin will cause a signal actuated by said testing or measuring coil to reject the coin if it is counterfeit.

Description

The present invention relates to coin-operated vending and service-rendering machines and, more particularly, it relates to coin-testing apparatus forming part of such machines, wherein acceptability of coins is determined by the magnetic properties thereof.

In one type of known coin-testing apparatus (see, for example, the USSR Author's Certificate No. 164,168, class 43 b 2/02, dated Nov. 28, 1963) the main testing member is an inductance coil disposed adjacent to the coin passage of the machine. An inductance coil with a single winding, disposed adjacent to the coin passage, is sufficient for testing coins made of nonmagnetic metals and alloys. However, many countries have within their coinage systems various coins made of magnetic alloys, which coins are to be distinguished from counterfeit coins and coin-imitating slugs.

It is, therefore, the main object of the present invention to create a coin-testing apparatus capable of testing coins made of magnetic alloys and materials and applicable in various coin-operated machines and mechanisms for the rejection of counterfeit coins and coin-imitating slugs, be they of magnetic or of nonmagnetic materials.

These and other objects are attained by the instant invention which comprises a coin-testing apparatus of the type wherein acceptability of a coin is determined by the magnetic properties thereof in that, according to the invention, two windings are provided disposed about a coin passage one above the other at such a distance that these windings have no inductive coupling, but such that a coupling between the windings is provided in the process of passing a coin of a fellow-magnetic alloy through the space between the windings, one of the windings being connected to a source of alternating current, and the other winding being connected to a measuring circuit.

It is also advisable for said windings of said inductance coil of the present coin testing apparatus, embodying the present invention, to be disposed within a protective ferromagnetic shield.

A coin-testing apparatus of a structure embodying the present invention is fully capable of accepting coins made of magnetic alloys and materials, at the same time rejecting counterfeit coins and slugs made of magnetic or nonmagnetic materials and alloys.

The invention will be more fully apparent from a consideration of an embodiment given by way of example, taken in conjunction with the accompanying drawing which shows a front perspective view (partly broken away) of an apparatus for determining acceptability of coins by the magnetic properties thereof, according to the invention.

Referring now the the drawing, a coin-testing apparatus, embodying the invention, comprises a coin passage 1 of a nonmagnetic material around which there are located an electric coil which includes two groups of turns or windings 2 and 3, which two windings are spaced from one another. The group of turns, or winding 2 is connected to an electric supply source, which in this embodiment is a generator of alternating current having a predetermined frequency and amplitude.

The group of turns, or winding 3 is connected to a measuring circuit.

It should be taken into consideration that an apparatus embodying the present invention may have more than two windings, which feature is essential in the event coins having different magnetic properties are to be tested and accepted by a single testing apparatus.

The spacing between the windings is such that they have no inductive coupling. The size of the electric coil, and the frequency and amplitude of the supply current are to be determined in every practical case, in accordance with the size and magnetic properties of the coins of the coinage system effective in a particular country.

It is unessential for the present invention which of the windings 2 and 3 is at the bottom and which at the top, and thus, in practical embodiments of the invention the primary winding 2 and the secondary winding 3 may change places.

The magnetic connection between the two windings 2 and 3 is established by a coin 4 being tested.

The coin-testing apparatus is provided with a ferromagnetic shield 5 which encompasses the two windings, protecting them from the influence of external electric and magnetic fields and also helping to increase the electromotive force (the EMF) induced in the secondary winding 3. The shield 5 may be of any appropriate shape.

The coin-testing apparatus, embodying the present invention, operates as follows.

A coin 4 to be tested is introduced in any known manner into the coin passage 1, and as a consequence it enters the alternating magnetic field created by the primary winding 2 and serves as a magnetic core between the primary winding 2 and the secondary winding 3. As a result, the EMF induced in the secondary winding 3 is built up. The value of the EMF thus induced now depends solely on the magnitude properties of the coin 4 being tested, the values of the supply current, supply frequency and supply voltage being constant, as well as the spacing between the two windings.

If the coin 4 is acceptable, the value of the EMF in the secondary winding lies within the limits to which the measurement circuit connected to the secondary winding 3 has been adjusted, and an acceptance signal is sent in any known way by this circuit (not shown) to a function-performing mechanism of the coin-operated machine, of which the coin-testing apparatus herein described forms a part.

In the case of an unacceptable coin, a counterfeit coin or a slug, the value of the EMF inadvertently falls out of these limits, and, consequently, either a rejection signal or no signal whatsoever is sent by the measurement circuit (not shown).

Claims

We claim:

1. A coin-testing apparatus of the type wherein acceptability of a coin is determined by the magnetic properties thereof, said apparatus comprising, in combination: a coin passage; two windings arranged around said coin passage one above the other with a spacing therebetween such that said windings have no inductive coupling, the magnetic connection between said windings being established as a coin of ferromagnetic alloy passes between said windings, one of said windings being connected to a source of alternating-current, and the other of said windings being connected to a measuring circuit.

2. An apparatus as defined in claim 1, further including a ferromagnetic screen enveloping both said windings.