Slot machine.

Background of the Invention

The present invention relates to a slot machine, and more particularly it relates to a slot machine in which the winning is so controlled as to be generated under a predetermined probability and in which the number of winnings to be generated are averaged for every preset number of games.

In a slot machine, generally a plurality of juxtaposed reels under high speed rotation are sequentially and automatically stopped, or alternatively each of the reels is independently stopped under manipulation of a stop button mounted for each reel. At the time of reel stop, a winning judgement is made in accordance with the combination of symbols stopped and positioned just upon a winning line, and coins (including tokens) are paid out as many number as the kind of winning indicates.

With such a slot machine, the number of all of the combinations of the symbols are decided from the number and kind of symbols disposed on respective one of the reels. Among all of the combinations, the number of winning symbol combinations are set in order to decide the probability of getting a win.

Although the winning probability is so established, it is natural that the probability of getting a win is governed by temporal chance while repetitively playing game. Thus, in the originally arranged winning probability, the actual winning is generated utterly by chance. This means that there is a sufficient possibility for the probability of getting a win to be varied with time. Therefore, if a large number of winnings are generated during a certain limited number of games, it is known statistically that the probability of getting a win is degraded during the following certain time duration. As a result, a player playing game during such a duration may lose his interest in the game because it is very hard to get a win.

Object of the Invention

It is a principal object of the present invention to provide a slot machine which can make a-player maintain to take interest in the game at any time period.

It is another object of the present invention to provide a slot machine which can control the symbol positioned upon a winning line in such a manner that the number of winnings can be averaged every time a predetermined number of games are carried out.

It is a further object of the present invention to provide a slot machine which can control to shift the symbol on a winning line by judging electronically with a microcomputer the combination of plural symbols to be stopped on the winning line, such that getting a win becomes easy or becomes hard.

Summary of the Invention

In order to attain the above objects, the present invention features in that storing means are provided for cumulatively storing under control of a microcomputer the number of played games and the number of issued winnings, respectively, the cumulative number of issued winnings during a preset number of played games are compared with the predetermined standard number of winnings, control means is actuated in response to the compared output to control the symbol positioned on the winning line, and the issuance of winnings are made adjustable. The control means may be of the one disclosed in Europian Patent Application No.84302387.0 filed on April 6, 1984. The present invention may be applied not only to a slot machine using a reel having symbols disposed on its periphery, but also to a slot machine of the type that game is played with a plurality of symbol characters displayed on a CRT.

Brief Description of the Drawings

Other objects and advantages of the present invention will become apparent during the following discussion of the accompanying drawings, wherein: <ul id="ul0001" list-style="none"><li>FIG.1 is a block diagram showing a construction of a slot machine according to the present invention.</li><li>FIG.2 is a flow chart showing the processings by the block construction shown in FIG.1.</li></ul>

Detailed Description of the Invention

Referring to FIG.1, by pulling an operation handle 1 mounted at the side of a slot machine, a start switch is rendered to turn on and a CPU(Central Processing Unit)30 is prepared to start a game. Thereafter a game program starts executing and in turn motor control circuits 12 through 14 are each supplied with a train of pulses. Then, stepping motors 16 through 18 rotate which also drive corresponding reels 3 through 5.

The number of drive pulses supplied to the motor control circuits 12 through 14 are counted with the CPU 30, the counted values being related to the rotary positions of the reels 3 through 5. Light intercepting tips 3a through 5a are formed on parts of the reels 3 through 5, and each rotation of the reels 3 through 5 is detected with photo-interrupters 19 through 21. When the photo-interrupters 19 through 21 detect the light intercepting tips 3a through 5a, the count value of drive pulses having been counted under control of the CPU 30 is cleared zero. Therefore, the kind of symbols passing below winning lines 22 through 24 and set for respective reels 3 through 5, can be related with one-to-one correspondence to the count value of the drive pulses supplied to the respective reels 3 through 5.

After each reel 3 through 5 obtains a constant rotation speed, upon depression of the stop switches 6 through 8, stop signals are input through respective depression detection circuits 9 through 11 to the CPU 30. In this case, drive pulses are terminated for delivery to the motor control circuits 12 through 14 corresponding to the respective stop switches 6 through 8 so that stepping motors 16 through 18 stop. In stead of the stop switches 6 through 8, random timers for automatically stopping each reel 3 through 5 may be provided.

At the time each reel 3 to 5 stops, the symbol stopping on the corresponding winning line 22 through 24 is identified basing upon the count value of drive pulses supplied to each reel 3 to 5. The combination of symbols on the winning lines 22 through 24 is judged under control of the CPU 30 whether it corresponds to a winning or not. If the combination corresponds to the winning, then a hopper device (not shown)is driven into actuation to pay out a number of coins corresponding in number to the kind of winnings.

The slot machine to which the present invention is applied further comprises a game number counter 50 and a winning number counter 51.The game number counter 50 receives a count up signal from the CPU 30 every time a game is played, and the number of played games are cumulatively stored. The winning number counter 51 receives a count up signal from the CPU 30 when it is judged a winning is generated at any one of played games, and the number of generated winnings are cumulatively stored. The cumulatively counted value of the game number counter 50, together with the constant number of games stored in a game number setting device 52 are input to a comparator 53. The comparator 53 enables a comparator 55 when both input values to the former coincide with each other. The comparator 55 compares whether the number of winnings counted by the winning number counter 51 are larger or smaller than the stored value of the winning number setting device 54 in which the standard number of winnings is stored. Then, a comparison output corresponding to the compared results is input to the CPU 30. The CPU 30 executes the following processings in accordance with the compared result by the comparator 55.

<ul id="ul0002" list-style="none"><li>(1)Winning counter) Standard winning number → Set a game losing flag</li><li>(2)Winning counter = Standard winning number → Set nothing</li><li>(3)Winning counter &lt; Standard winning number → Set a winning flag</li></ul>

Upon reception of a coincidence signal from the comparator 53, the count value of the game number counter 50 is reset to "₀", and also the count value of the winning number counter 51 is reset to "0".

Following the above and at a start of a next game, the CPU 30 checks setting states of the winning flag and the game losing flag at the end of the preceding game. In the case the winning falg is set, drive adjustment pulses are supplied through drive adjustment sections 32 through 34 to the motor control circuits 12 through 14 so as to drive the stepping motors 16 through 18 to the positions where a winning can be gotten. The above operation is carried out in the case that without the help of the above operation the reels 3 through 5 stop at the positions loosing a game due to a poor timing for manipulation of the stop buttons 6 through 8. Since the rotary positions of the stepping motors 16 through 18 can be judged from the number of drive pulses, the number of drive adjustment pulses for stopping the stepping motors 16 through 18 at the positions where a winning is gotten can previously be calculated. Similarly, in the case that the game loosing flag is set, the above mentioned drive adjustment pulses are supplied so that the stepping motors 1 through 18 are driven into rotation to the positions losing the game, and without the drive adjustment pulses the stepping motors 16 through 1 8 should have been stopped at the positions a winning is gotten.

FIG.2 is a flow chart showing the above described processings. By executing the above processings, games are repeated while affirming, at intervals of the number of games preset in the game number setting device 52, whether the number of generated winnings during each interval is appropriate or not. It is noted that in a winning flag setting state, a too large shift for reel positions causes the player become aware of it, so it is preferable to shift one or two frames of the symbol. Therefore, if a winning is not gotten with such amount of shift, the winning flag setting state is retained until such processing in compliance with the winning flag is executed and the flag is reset.

It is known that in an ordinary slot machine, a large number of codes for winnings exist due to the various kinds of winnings. In this case, the constitutional elements 50 through 56 shown in FIG.1 may be added to have as many number as the number of the winning codes. Further in this case, the judgements shown in FIG.2 are repeated as many times as the number of winning codes. It is also posible to simplify the construction by grouping several kinds of winnings into a single block and using a single counter, not by using each winning code for each processing.

Instead of the game number counter 50 used in the above embodiment, a coin number: counter for cumulatively storing the number of coins inserted at every game may be used, and the count value of the number of coins obtained from the counter may be used as a game number. With such modification, in a slot machine of the type that three symbols appear through a slot machine display window for each reel, a plurality of winning lines, such as lateral three lines and also two oblique lines, can be set, and the number of effective winning lines increase in correpondence with the number of coins inserted for a game, if the number of coins inserted are plural in number, it is judged that the same number of games are executed. Therefore, the limit value stored in the game number setting device 52 can be used effectively also in this modified embodiment. In this case, it is quite certain that the winning judgement is carried out for every one of the winning lines, and that when a plurality of winnings are generated, the corresponding number of count up signals are delivered. Furthermore, the present invention may equally be applied to a credit type slot machine in which prior to the start of a game, a number of coins are inserted and the display of the number of coins inserted is changed in accordance with the results of the game.

Having described the present invention as related to the embodiment shown in the accompanying drawings, it is our intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.