GB2165386A - Entertainment machines - Google Patents

Abstract

A coin-operated entertainment machine, such as a fruit machine, has a counter which is incremented and decremented in correspondence with prizes awarded and games played. There is a preselected ratio of the increment magnitude to the decrement magnitude, and the current count of the counter is monitored in relation to a predetermined reference count. The operation of the machine is influenced to compensate for departure of the monitored count from the predetermined count. In order to introduce unpredictability the predetermined reference count is changed so as to be different for different games.

Description

SPECIFICATION Entertainment machines This invention relates to coin- (or token-) operated entertainment machines and is particularly although not exclusively concerned with fruit machines.

Fruit machines are usually designed to give overall a preselected payout ratio i.e. a preselected ratio of the coins (or tokens) paid out in winning games to the coins (or tokens) inserted into the machine and credited for the playing of games.

With the aim of ensuring a relatively even distribution of payouts (e.g. to avoid long runs of winning games followed by long runs of losing games) it is known to provide a compensator which monitors the payout ratio game by game and initiates action, as necessary, to influence the random selection of wins and thereby attempt to hold the ratio at all times close to the preselected level.

One form of compensator comprises a counter which is incremented and decremented relative to a fixed reference count.

The counter is decremented for each game played by one unit and is incremented for each win by a number of units which is a function of the value of the win and the desired payout ratio. The random selection of wins is influenced by the current state of the counter i.e. the difference between the current count and the fixed reference count. Thus, if the current count lies within a middle range close to the reference count, the likelihood of a payout corresponds to the preselected payout ratio. If the current count is outside this middle range the likelihood of a payout is progressively increased or decreased in successive probability bands.

A number of problems can arise with this known arrangement. Firstly, an element of predictability may be introduced in that, for example, following a large payout, further payouts may be inhibited in the ensuing games to allow return of the counter of the middle range close to the reference count, and this may adversely affect player interest. Secondly, because changes in payout probability are relied on to return the payout ratio of the desired level the compensator may be slow acting; i.e. after a wide deparature from the predetermined ratio, many games may be required before the ratio is regained. Thirdly, due to the provision of the various probability bands the compensator is of a complex nature and can be difficult to design and set up during development of the machine.This is particularly problematical in the case where multiple compensators are used to monitor the distribution of different kinds of payouts as well as the overall payout ratio, in so for as such compensators have to be designed and set up individually. Compensator complexity could be reduced by reduction of the number of probability bands e.g. by using a compensator which, in the extreme, has only two states of influence-one in which wins are totally inhibited and one in which wins are generated. This would simplify design but would be unacceptable in the context of the conventional system in so far as it would introduce undesirable predictability.

An object of the present invention is to provide a compensator with which the aforementioned problems can be overcome or at least appreciably reduced in an acceptable manner.

According to the invention therefore there is provided a coin- (or token-) operated entertainment machine with which games can be played involving the random selection of symbol combinations and a prize is awarded where such a selected combination is of a predetermined winning nature, said machine having a compensator including a counter which is incremented and decremented respectively in correspondence with prizes awarded and games played, with the ratio of the increment magnitude per prize to the decrement magnitude per game being a function of a preselected prize award ratio, and a control device is provided which is responsive to the difference between the current count of the counter and a predetermined reference count so as to influence the likelihood of an award in correspondence therewith, characterised in that said predetermined reference count is arranged to change so as to have a different value for different games.

With this arrangement, avoidance of a predictability is obtained by virtue of the variable factor introduced by the changing reference count. This introduces unpredictability in a particularly satisfactory manner and obviates the use of different probability bands. Accordingly, it is acceptable to use a compensator which operates quickly and in a simple manner and, in particular, has only two states of influence respectively in which wins are avoided and in which wins are demanded.

The arrangement is preferably such that the reference count is changed or reselected immediately following any win.

Preferably also, the reference count is changed between the middle value of the counter and the lowest count which is achievable by decrementing in correspondence with the playing of games. In this respect, it is to be understood that reference is made herein, for the sake of convenience, to incrementing on award of prizes and decrementing on playing of games but of course the opposite arrangement can be utilised.

The counter is preferably of a digital nature whereby incrementation and decrementation are effected in steps. The counter may be defined by a separate component of the machine or may be incorporated in software.

The counter may be incremented and decre mented in any suitable manner in dependence on game playing and the award of prizes.

Thus, game decrementation may correspond to numbers of games played or to coins (or tokens) inserted and credit accrued for the playing of games. Similarly, award incrementation may be effected in correspondence with numbers of awards or value of awards e.g.

value related to playing credits.

The control device may influence the award of prizes in any suitable manner. Thus, for example, the symbol combination may be selected with prior reference to the control device to ensure, as necessary, that a certain win or class of win is demanded or avoided.

In this respect the arrangement may be such that the outcome of a game is guaranteed i.e.

a win is definitely inhibited or generated as required. Thus, instead of randomly selecting the symbol combination a predetermined such combination may be deliberately selected.

It is however also possible to introduce some uncertainty in that, for example, combinations are repeatedly randomly preselected but not displayed and utilised until an appropriate winning or losing combination is obtained or until a predetermined number of preselection operations have been performed (say 25) whichever occurs first. Alternatively or additionally the control device may be used to influence the value of an attained win or the award of a consolation prize or the like.

Most preferably the machine of the invention is a fruit macine and the symbol combination is selected and displayed to the player with the aid of rotatable reels, a vdu device, an array of squares which can be selectively illuminated, or the like.

Preferably also, the awarded prizes constitute or include coins or tokens.

The invention will now be described further by way of example only and with reference to the accompanying drawings in which: Figure 1 is a diagrammatic front view of one form of a fruit machine according to the invention; and Figures 2 and 3 are graphs indicating the mode of operation of a compensator of the machine of Fig. 1.

The machine shown in Fig. 1 is a fruit machine having three reels 1, 2, 3 which are rotatable within a housing 4 behind a window 5 in a front panel 6.

Each reel 1, 2, 3 has pictures of fruit (designated A, B, C) at 20 positions around its periphery, and rotation of each reel is effected and also arrested by a microprocessor-controlled stepping motor, the arrangement being such that the reel always comes to rest in precise registration with the window. Each stopping position is identified by the microprocessor control circuitry in known manner.

In use, the machine is actuated by a player by insertion of one or more coins or tokens into a coin mechanism 7 and a starter button 8 is pressed to cause the three reels 1, 2, 3 to rotate for different random periods of time before coming to rest. When the reels 1, 2, 3 come to rest, their stopping positions are known and a win indication is produced in the event that the identified stopping positions correspond to the display of a predetermined winning combination of fruit (say three fruit of the same kind) at predetermined positions in the window 5 (e.g. on a horizontal win line passing through the middle of three displayed fruit for each reel).

The usual player-operable "nudge" and "hold" buttons 9, 10, 11 may be provided for each reel.

The microprocessor control circuitry within the machine includes, in software, a compensator comprising a counter, a reference point adjusting device and a control device.

The counter can be incremented and decremented in steps between a low count and a high count which are designated by way of illustration in Figs. 2 and 3 and -100 and +100. For each game, which requires a fixed value of coins (or tokens) to be inserted into the machine and credited for game playing purposes, the counter is decremented by one step. For each win which results in a payout (or the crediting of a payout to the player) the counter is incremented by a number of steps which is a function of the coin or token value of the win and a fixed payout ratio in accordance with which the microprocessor control circuitry has been pre-set.

At the start of each game the current count of the counter is utilised by the control device to control or influence the outcome of the game.

As so far described, the compensator is identical with a known kind of compensator.

With the known compensator the control device is responsive to the difference between the current count and a pre-set reference count which is the middle zero point. If the difference is zero, or within a middle band close to the zero point, the control device exerts no influence on the outcome of the game-the likelihood of attaining a win resulting in a payout is statistically in accordance with the pre-set payout ratio.

If the difference lies in an upper band extending above this middle band up to the top counter limit (i.e. 100), the likelihood of attaining a win is reduced (e.g. some kinds of wins are rejected). This control can be achieved because the stopping positions of the reels are determined in advance by the microprocessor circuitry. Similarly, if the difference lies in a lower band the likelihood of attaining a win is increased. If the difference is at a maximum (i.e. 100 or -100), all wins are inhibited or a win is guaranteed as appropriate. In practice successive upper and lower bands with progressively increasing or decreasing degrees of win likelihood are used.

As already explained, a compensator of this conventional kind is extremely complicated to design and set up during development of the machine. In order to avoid this complexity the compensator is arranged to have only two operational states rather than bands of influence and this arrangement will now be described first with reference to Fig. 2. As shown in Fig. 2, assuming that a maximum win is initially obtained of equivalent value 10 and the payout ratio is 10%, the counter reaches the maximum incremental count (100), further wins are then inhibited and the counter is decremented towards the zero reference count as successive losing games are played. That is, at each game the compensator is in its win-inhibit state until the zero count is reached. On reaching the zero count the compensator exerts no influence.If the count falls below zero then the compensator adopts its win-demand state. As shown in Fig. 2 the reference count is fixed at the zero point and this could give rise to predictability of winning and losing games.

In order to avoid this predictability, and as shown in Fig. 3, after each win the reference count is set, on a random basis, under the control of the reference point adjusting device between the limits of the middle count and the lowermost count.

The effect of this is to give the same overall award ratio but the short term effect is changed in a randomly varying manner due to the change in the reference point. Thus, as shown in Fig. 3, if a maximum win is achieved it is not necessarily the case that the counter has to return to the middle count (zero in the drawing) before the influence of the control device is eliminated. Instead a greater or lesser number of losing games may be required depending on the setting of the reference point. In effect, the monitoring of the payout ratio is carried out with reference to varying numbers of games. With the arrangement of Fig. 2, monitoring is always carried out with reference to 100 games. With the arrangement of Fig. 3, monitoring is carried out e.g.

with reference to 150 games, then with reference to 50 games etc. Thus, a relatively regular distribution of winning and losing games can be achieved but a predictable pattern is avoided. Accordingly, player interest can be maintained and design and development can be much simplified.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only. Moreover it is to be understood that the graphs of Figs. 2 and 3 are only for illustration purposes. Thus, although Fig. 3 shows two reference points on the "zero line" and two below with each win at the maximum level, in practice there may be a greater or smaller frequency of reference point changes and all wins will not of course be of a maximum nature followed by successive losing games returning the compensator to the reference count; in practice the graph will be of a more erratic nature involving a greater frequency of smaller changes.

Moreover, although reference is made to only one compensator, in accordance with conventional practice a plurality of compensators may be provided, each monitoring a different payout parameter, and each such compensator may be of the kind described above.

Claims (13)

1. A coin- or token-operated entertainment machine with which games can be played involving the random selection of symbol combinations and a prize is awarded where such a selected combination is of a predetermined winning nature, said machine having a compensator including a counter which is incremented and decremented respectively in correspondence with prizes awarded and games played, with the ratio of the increment magnitude per prize to the decrement magnitude per game being a function of a preselected prize award ratio, and a control device is provided which is responsive to the difference between the current count of the counter and a predetermined reference count so as to influence the likelihood of an award in correspondence therewith, characterised in that said predetermined reference count is arranged to change so as to have a different value for different games.

2. A machine according to claim 1, wherein the arrangement is such that the reference count is changed or reselected immediately following any win.

3. A machine according to claim 1 or 2, wherein the reference count is changed between the middle value of the counter and the lowest count which is achievable by decrementing in correspondence with the playing of games.

4. A machine according to any one of claims 1 to 3, wherein the counter is of a digital nature whereby incrementation and decrementation are effected in steps.

5. A machine according to any one of claims 1 to 4, wherein game decrementation corresponds to numbers of games played or to coins (or tokens) inserted and credit accrued for the playing of games.

6. A machine according to any one of claims 1 to 5, wherein award incrementation is effected in correspondence with numbers of awards or value of awards.

7. A machine according to any one of claims 1 to 6, wherein the symbol combination is selected with prior reference to the control device to ensure, as necessary, that a certain win or class of win is demanded or avoided.

8. A machine according to claim 7, wherein the arrangement is such that the outcome of a game is guaranteed in that a win is definitely inhibited or generated as required.

9. A machine according to claim 8, wherein instead of randomly selecting the symbol combination a predetermined such combination is deliberately selected.

10. A machine according to claim 7, wherein the arrangement is such that combinations are repeatedly randomly preselected but not displayed and utilised until an appropriate winning or losing combination is obtained or until a predetermined number of preselection operations have been performed whichever occurs first.

11. A machine according to any one of claims 1 to 10, wherein the control device is used to influence the value of an attained win or the award of a consolation prize.

12. A machine according to any one of claims 1 to 11, which is a fruit machine.

13. A machine according to claim 1, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.