GB2107875A - Inductive switches - Google Patents

Abstract

In fruit machines and other amusement with prizes machines which supply prize money and change for coins of a larger denomination from a common pool of coins in the form of a column an inductive switch is provided for sensing the height of the column to avoid the undue depletion of the pool to a level where prizes cannot be paid out. Column of coins 3 is supported in a tube 2 around which two printed circuit coils are coaxially arranged adjacent one another at a predetermined height. The coils are connected in an oscillator circuit such that when the height of the column of coins is level with the coils the oscillator is prevented from oscillating and a relay is de-energised. However when no coins are present at this level the oscillator is free running and the relay energised. <IMAGE>

Description

SPECIFICATION Inductive switches The invention relates to an inductive switch for sensing the height of a column of coins or tokens, primarily but not exclusively for payout devices for amusement-with-prizes machines such as fruit machines.

It is common practice in fruit machines and other amusement with prizes machines to supply prize money and change for coins of a larger denomination from a common pool of coins of one denomination. It is also common for the machines to operate by, and pay out prizes in, coin-like tokens of value, and in the following description and any claims, the term "coin" is to be regarded as referring also to a coin-like token.

To avoid the undue depletion of the pool to a level where prizes cannot be paid out, it is desirable to cease offering change when the pool has reduced to a predetermined number of coins.

In the conventional arrangement, the pool of coins is formed as a column within a tube, so that the presence of a predetermined number of coins in the pool is assured when the column reaches a predetermined height within the tube. In the mechanisms known hitherto, a micro switch is provided externally of the tube, the switch being actuated by an actuator arm passing through a hole or slot in the tube at the said level. The actuator arm is arranged ta be displaced when the column of coins reaches that level relative to its position when the column does not reach that level, and the state of the micro switch is thus arranged to be changed according to whether or not there is at least a predetermined number of coins in the tube.

The arrangement tends to suffer from mechanical faults, however, and it is relatively inflexible in that the position of the hole or slot is predetermined by the height of the column at which the change of state of the switch is required to take place.

According to the present invention there is provided apparatus for sensing the height of a column of coins comprises means for supporting the column of coins, two electrical coils arranged to exhibit a variation in inductive coupling according to whether or not the column, supported by said support means, extends up to a predetermined level, and means to detect such variation in inductive coupling.

Preferably the support means comprises a tube of inner diameter corresponding to the diameter of the coins, and preferably again the coils are arranged to be coaxial with the column when supported by the support means and adjacent one another at or in the region of the predetermined level.

The detecting means may be an electrical circuit able to detect variation in inductive coupling by the presence or absence of electrical oscillations therein.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, of which: Fig. 1 shows in perspective a coin support tube provided with column height sensing means including coils encapsulated in a potting compound; Fig. 2 is a detail of the apparatus of Fig. 1 with the potting compound removed to reveal the coils; and Fig. 3 is an electrical circuit diagram incorporating the coils of Fig. 2.

As shown in Fig. 1, the apparatus comprises a platform 1 for supporting a vertical column or stack of coins or coin-like tokens thereupon, and a tube 2 of plastics material having an internal diameter slightly greater than the diameter of the coins for which the apparatus is designed. In use, coins are introduced into the tube through the open upper end 3, fall through the tube, and build up as a column upon the platform 1 to provide a pool of coins from which prizes may be paid out or a predetermined number of coins may be issued in exchange for a coin of larger denomination. The processes by which the pool of coins is diminished are conventional and, if not compensated by the introduction of an adequate number of further coins, result in a reduction in the height of the column of coins within the tube 2.

In order to detect a reduction in the height of the column of coins below a predetermined value in order that the issue of change may be discontinued or other remedial measures taken, two coils of wire L1, L2 each made up of about ten turns of wire, are wound adajcent to one another about a cardboard sleeve 4 which fits outside the tube 2 and is supported at a predetermined level above the platform 1 by means of a clip 5 and a collar 6 which is tightly fixed about the tube 2.

Each of the coils L1, L2 is electrically connected by connector 7 in a circuit as shown in Fig. 3.

In the circuit, T1, T2 are general purpose high gain transistors, and the coils L1, L2 and the transistorT1 form, with resistors R1, R2 and capacitors C1 and C2, a stabilized oscillator.

Diodes Di, D2 and capacitors C3 and C4 form a "diode pump" to convert oscillating voltages across C2 to direct current voltage summed by C4. During oscillation, C4 becomes charged sufficiently to switch on transistor T2 and hence to energise the relay RLY.

When no coins are located in the vicinity of the coils, that is to say when the column of coins is so depleted that the uppermost coin is below the level of the lower coil, the circuit components are such that the oscillator is free running by reason of the coupling effect of the two coils. This condition is arranged to be maintained even when coins are falling through the coils down the tube.

However, when a coin remains located in the vicinity of the coils, that is to say when the column has increased to at least approximately the level of the coils, the coupling effect of the two coils is reduced to such an extent that oscillation in the circuit is prevented, the transistor T2 is switched off and the relay RLY is de-energised.

The de-energization of the relay can be used to produce an audible, visible or other signal or it may be used to cause the provision of change to be discontinued until, with the addition of further coins, the column reaches the height of the coils, when the oscillation of the circu recommences, recharging condensor C4, switching on the transistorT2 and again energising the relay RLY.

In the embodiment shown in Figs. 1 and 2, the circuit is provided by means of a printed circuit board 8 which, like the coils, is encapsulated in a potting compound, leaving free from encapulation only the output pins 9 which comprise the relay contacts and the means by which the circuit is connected to a source of direct electrical potential.

The apparatus, being entirely electrical, does not suffer from mechanical faults as does the detector of the prior art and, moreover, the height at which the coils are arranged about the tube 2 can readily be varied by a relocation of the supporting collar 6.

Claims (Filed on 15. 9. 82).

1. Apparatus for sensing the height of a column of coins comprising means for supporing the column of coins, two electrical coils arranged to exhibit a variation in inductive coupling according to whether or not the column, supported by said support means, extends up to a predetermined level, and means to detect such variation in inductive coupling.

2. Apparatus according to Claim 1 wherein the support mean comprises a tube of inner diameter corresponding to the diameter of the coins.

3. Apparatus according to Claim 1 or Claim 2 wherein the coils are arranged to be coaxial with the column when supported by the support means and adjacent one another at or in the region of the predetermined level.

4. Apparatus according to any preceding Claim wherein the detecting means is an electrical circuit able to detect variation in inductive coupling by the presence or absence of electrical oscillations therein.

5. Apparatus for sensing the height of a column of coins substantially as described with reference to the drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. oscillation in the circuit is prevented, the transistor T2 is switched off and the relay RLY is de-energised. The de-energization of the relay can be used to produce an audible, visible or other signal or it may be used to cause the provision of change to be discontinued until, with the addition of further coins, the column reaches the height of the coils, when the oscillation of the circu recommences, recharging condensor C4, switching on the transistorT2 and again energising the relay RLY. In the embodiment shown in Figs. 1 and 2, the circuit is provided by means of a printed circuit board 8 which, like the coils, is encapsulated in a potting compound, leaving free from encapulation only the output pins 9 which comprise the relay contacts and the means by which the circuit is connected to a source of direct electrical potential. The apparatus, being entirely electrical, does not suffer from mechanical faults as does the detector of the prior art and, moreover, the height at which the coils are arranged about the tube 2 can readily be varied by a relocation of the supporting collar 6. Claims (Filed on 15. 9. 82).

1. Apparatus for sensing the height of a column of coins comprising means for supporing the column of coins, two electrical coils arranged to exhibit a variation in inductive coupling according to whether or not the column, supported by said support means, extends up to a predetermined level, and means to detect such variation in inductive coupling.

2. Apparatus according to Claim 1 wherein the support mean comprises a tube of inner diameter corresponding to the diameter of the coins.

3. Apparatus according to Claim 1 or Claim 2 wherein the coils are arranged to be coaxial with the column when supported by the support means and adjacent one another at or in the region of the predetermined level.

4. Apparatus according to any preceding Claim wherein the detecting means is an electrical circuit able to detect variation in inductive coupling by the presence or absence of electrical oscillations therein.

5. Apparatus for sensing the height of a column of coins substantially as described with reference to the drawings.