GB2160345A - Gaming machines - Google Patents

Abstract

The rim of a reel for a gaming machine has an inner portion 10 formed at an interval of 90 degrees with toothed portions 14, 14'. One of these portions carries a tab 13 which is capable of adjustment in a circumferential direction in steps determined by the pitch of the teeth in the portions 14, 14'. The tab co- operates with a beam of light to control a stepper motor driving the reel and thus to determine a datum angular position for the reel which can be adjusted by adjusting the position of the tab 13. <IMAGE>

Description

SPECIFICATION Gaming machines This invention relates to gaming machines, sometimes referred to as fruit machines, or amusement machines. As is well known, such machines include a mechanism comprising a number of reels marked along their circumferential edges with symbols such as fruit. In operation, the reels are caused to spin and when they come to a stand-still, the positions of the symbols on the different reels in relation to a so-called "win" line determine whether or not a player has won. The win line is normally horizontal and the reels are arranged to stop so that each reel represents a symbol which is in register with the win line.

It is important that this register should be accurate.

The symbols on the reels are printed on a length of strip or tape which if fixed in position around the edge of each reel and errors in the accuracy with which each symbol is brought into register with the win line when the motor driving the reel is stopped can typically be introduced either by inaccurate reel tape positioning or by cabinet manufacture variations. Although minute errors can be tolerated, anything larger than a few tenths of a millimetre immediately becomes visible, particularly if some of the adjacent reel module symbols are very slightly above the win line and some are very slightly below it.

When a reel is driven by a stepper motor, it is essential to determine a datum position from which all angular movements are measured. In particular, at the time of initially switching on, it is necessary to re-establish that datum by turning the reel until a signal corresponding to the datum position is established. For this purpose, the common practice is for the reel to be moulded with a tab or other form of projection which interrupts a beam of light energising an optic device at a specific point in the rotation of the reel, this interruption generating a signal denoting the datum position. The subsequent positions at which the reel then stops are determined by counting the number of steps of the motor from the datum position.When the reel stops in this way after a predetermined number of steps of the motor, there is a risk that the corresponding symbol on the tape will not be in accurate register with the win line.

According to the present invention, instead of forming an integral part of the reel in the usual way, the tab is adjustably mounted on the reel so as to be capable of movement in a circumferential direction, preferably in discrete steps or increments, each equal to the minimum amount of adjustment likely to be required in practice. As just explained, the position of the reel when it stops corresponds to a specific number of steps of the motor from the datum postion and if an error is then present, it can be corrected by corresponding adjustment of the datum position itself, i.e. by adjustment of the tab in relation to the body of the reel. If only a minimum adjustment is required, the tab can be moved through a single step or increment, while for greater amounts it will need to be moved through two, three or more such increments.

It is found that a convenient size for each step of adjustment is half a degree which, for a typical reel diameter of 228 mm, represents 0.99 mm of circumferential movement. For a step angle of 1.8 , it can be calculated that the maximum error, amounting to half a step, is 1.79 mm, so that movement of the tab through two steps of adjustment, each of 0.99 mm gives a total correction of 1.98 mm, thus reducing the error to 0.19 mm. This is the equivalent of only eight thousandths of an inch, probably being less than the thickness of the printed win line and is consequently entirely acceptable.

The adjustment of the tab on the reel is preferably made by means of a ratchet-type mechanism, e.g. with one or preferably two pawls on the tab co-operating with a ratchet on the rim of the reel in a resilient manner.

For this purpose, the body of the tab may be formed with a generally U-shaped portion which, as a result of the resilience of the moulding, grips on opposite sides of the rim of the reel, one side of the rim being formed with the ratchet teeth and the co-operating part of the tab being formed with the pawl or pawls. The ratchet teeth on the reel need only extend for a centimetre or two since no error is likely to be greater than this. As already explained, the tape bearing the symbols is fixed in position in relation to calibration marks on the reel and, although errors may be introduced, they are never very large. The use of such a ratchet arrangement makes the adjustment positive and foolproof. When the tab is moved there is an audible click and a corresponding sensation in the finger of the user.It is, therefore, extremely simple to adjust the tab by the required number of steps merely by the sense of feel and without the need for the tab even to be visible. Once adjusted, the engagement between the ratchet and the pawl or pawls holds it positively in position.

An example of construction in accordance with the invention is illustrated in the accompanying drawings, in which: Figure 1 is an elevation of part of the rim of a reel; Figure 2 is a cross sectional view to a greatly enlarged scale of the rim seen in Fig.

1 with an adjustable tab in position on it; and Figure 3 is a sectional view on the line Ill-Ill in Fig. 2.

Fig. 1 is a view of the surface of the rim of the reel, omitting the supporting spokes. The rim comprises an inner rounded surface 10, the shape of which is best seen in Fig. 2, a projecting web 11 and an outer portion 1 2. A tab is shown in dotted lines at 13, and can be adjusted in a circumferential direction along the length of a toothed or ratchet portion 1 4 formed on the rounded surface 10. In a particular example, the portion 1 4 may be approximately two and a half centimetres long and a second similar surface 14' may also be included to provide an alternative mounting for the tab 1 3. The purpose of this alternative mounting is to cater for machines, some of which have front access and some back access.The tab 1 3 can therefore be mounted either at 1 4 or 14', depending on which is more convenient for the machine in question.

The main body of the tab 1 3 forms three sides of an open rectangle and projecting from this is an attachment portion 16. The portion 1 6 is in the general form of a U, one iimb 1 7 of which is curved to conform with the curvature of the surface 10 and is formed with two spaced pawls 19 (see Fig. 3) which co-operate with the ratchet teeth 14. The other limb 1 8 of the U is formed with a projection 20 which engages a correspondingly shaped groove in the rear of the curved surface 1 0, and thus holds the tab in position on the rim of the reel.The tab 1 3 is formed of a resilient plastics material so that it can be sprung into position on the curved surface 10, the projection 20 first being engaged in its corresponding groove and the remainder of the tab then being pivoted about this until the surfaces 10 and 1 7 come into engagement.

The tab 1 3 can be readily adjusted along the ratchet surface 1 4 by manipulation by means of the finger and thumb, each step of movement being accompanied by an audible click which is assisted by the sense of feel as the pawls 19 move over the ratchet teeth. As described above, the tab 1 3 co-operates with a beam of light to control a stepper motion driving the reel and thus to determine a datum position which can be adjusted to correct any error by adjustment of the tab 1 3.

Depending on the magnitude of the error to be corrected, the tab 1 3 may need to be adjusted by a distance equivalent to one or more teeth.

Claims (5)

1. A reel for a gaming machine which includes, for each reel, a stepper motor drive and an optical system for determining a datum position operated by the interruption of a beam of radiation by a tab on the reel, the reel having a tab which is adjustably mounted so as to be capable of movement in a circumferential direction and thus to produce corresponding adjustment of the datum position.

2. A reel according to claim 1, in which the tab is adjustable in discrete steps or increments.

3. A reel according to claim 2 in which the adjustment of the tab is made by means of a ratchet-type mechanism comprising a pawl on the tab co-operating resiliently with a row of teeth on the rim of the reel.

4. A reel according to claim 3. in which the body of the tab is formed with a generally U-shaped portion which grips on opposite sides of the rim, one side of the rim being formed with the teeth and the co-operating part of the tab being formed with a pawl or pawls.

5. A reel for a gaming machine substantially as described and as illustrated with reference to the accompanying drawings.