Information
-
Patent Grant
-
6540227
-
Patent Number
6,540,227
-
Date Filed
Wednesday, May 30, 200123 years ago
-
Date Issued
Tuesday, April 1, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Layno; Benjamin H.
- Collins; Dolores R.
Agents
-
CPC
-
US Classifications
Field of Search
US
- 273 143
- 345 205
- 345 418
- 029 721
- 029 741
- 348 739
- 312 114
- 312 234
- D06 432
- 217 11
- 217 58
- 217 10
- 463 20
-
International Classifications
-
Abstract
A case of a stepping motor is divided by a partition. One of divided portions of the case contains a rotor and a stator of the stepping motor. A small-sized drive gear is fixed to a drive shaft integrally rotated with the rotor. The drive gear is meshed with a larger gear of a transmission gear. This transmission gear includes a smaller gear integrally rotated with the larger gear. The smaller gear is meshed with a large-sized output gear fixed to an output shaft of the stepping motor. Two pairs of the reduction gear mechanisms transmit a rotation of the drive shaft to the output shaft in a reduced state.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a symbol displaying unit used for a game machine of a slot machine, a Japanese upright pinball machine, and so forth. In particular, the present invention relates to a symbol displaying unit in which a reel having symbols arranged on an outer periphery thereof is driven by a stepping motor.
2. Description of the Related Art
A slot machine using a symbol displaying unit is well known from Japanese Patent Laid-Open Publication No. 6-39085 (Japanese Patent No. 2,920,027) and so forth. In such a symbol displaying unit, nine reels having symbols arranged on outer peripheries thereof are disposed in a three-by-three matrix, and the respective reels are driven by an individual motor. When a start button of the slot machine is operated after putting a certain number of tokens into the slot machine, the symbol displaying unit is activated to simultaneously rotate the nine reels. After that, a stop button is operated to stop the reel. Alternatively, the reels are stopped based on a signal outputted from a random timer. When a specified symbol combination are obtained on any one of judgement lines, it is judged to be a hit. Incidentally, the judgement lines are, for instance, three vertical lines, three horizontal lines and two diagonal lines which are set so as to combine three reels straightly. When the hit occurs, the tokens are paid out in accordance with a number of the invested tokens and a hit combination.
The above symbol displaying unit of the nine-reel type attached to the slot machine is utilized in a recent Japanese upright pinball machine called as “pachinko”, such as described in Japanese Patent Laid-Open Publication No. 9-266979. In this pinball machine, the reels are simultaneously rotated when a game ball enters a predetermined start hole. After the reels have stopped, an extra game unit called “attacker” is opened if the hit occurs. While the attacker is opened, almost all of the game balls flowing on a game board enter the attacker. When a predetermined number of the game balls enter the attacker, this attacker is briefly closed, and then is opened again. The operation of the attacker is repeated within an extent of sixteen times, for example. Thus, a player can obtain a large number of game balls when the hit occurs on the symbol displaying unit.
In the slot machine and the pinball machine described above, a pay-out ratio greatly fluctuates in accordance with a frequency of the hit occurring on the symbol displaying unit. In view of this, probability of hit occurrence is controlled by a microcomputer. When the symbol displaying unit is activated, the microcomputer extracts a certain number by using a random-number generator, and controls the motor of the reel so as to satisfy a result corresponding to the extracted number. Extraction of the number is performed under a predetermined probability of the hit occurrence. For the purpose of controlling the motor easily, a stepping motor is utilized as the motor for driving the reel. Based on a number of drive pulses supplied to the stepping motor, stop control of each reel is performed.
Meanwhile, the stepping motor is rotated by unit step angle whenever the drive pulse is supplied thereto. A number of steps necessary for one rotation is fixed. In case the number of steps is small, the step rotation of the reel is found out by a player when a rotational speed of the stepping motor is decreased for stopping the reel. In this case, the player is likely to have a strange feeling. This problem may be improved by using the stepping motor whose unit step angle is small, or whose step number for one rotation is large. However, such a stepping motor has a large size and is expensive so that it is difficult, because of a space for attachment and so forth, to use this stepping motor for the symbol displaying unit having nine reels arranged in the three-by-three matrix. Especially, it is difficult to be employed in the symbol displaying unit used for the pinball machine.
In the meantime, such as described in the foregoing Publication No. 9-266979, is well known a structure in which a gear fixed to a drive shaft of the stepping motor is meshed with an internal gear formed on an inner periphery of a rotary bearing. The gear of the drive shaft has a small number of teeth, and the internal gear of the rotary bearing has a large number of teeth. In this structure, the rotation of the stepping motor is transmitted to the reel in a reduction state. For the purpose of making the low-speed step rotation inconspicuous under usage of one-pair gears, it is required to increase the teeth number of the internal gear. Thus, it is necessary to enlarge the reel. Moreover, since the gear fixed to the drive shaft of the stepping motor is meshed with the internal gear of the reel in a state that the reel is rotatably supported by a fixed supporting shaft, there arise problems in that a number of parts for constituting a reel assembly increases, and in that assembling these parts becomes complicated. Further, since driving force is transmitted at a position separated from the rotational center of the reel, there arises another problem in that the rotation of the reel is likely to be biased in accordance with repetition of usage.
SUMMARY OF THE INVENTION
In view of the foregoing, it is a primary object of the present invention to provide a symbol displaying unit used for a game machine in which a reel can be downsized.
It is a second object of the present invention to provide a symbol displaying unit used for a game machine in which a reel may be smoothly rotated, using a stepping motor whose step number is small.
In order to achieve the above and other objects, the symbol displaying unit according to the present invention comprises a stepping motor, in a motor case of which at least two pairs of reduction gear mechanisms are contained.
The stepping motor includes a drive shaft and an output shaft. The drive shaft is integrally rotated with a rotor of the stepping motor, and the output shaft projects to the outside of the motor case. A rotation of the drive shaft is transmitted to the output shaft in a reduced state by the reduction gear mechanisms. Further, the motor case is disposed inside a reel so as to secure the output shaft to the reel.
The top of the output shaft is provided with a reel attaching portion having a contour of a non-circular shape. Meanwhile, one side of the reel is integrally formed with an attachment portion, an inner shape of which corresponds to the contour of the reel attaching portion of the output shaft. When fixing the reel to the output shaft, the reel attaching portion of the output shaft is fitted into the attachment portion of the reel. Then, a central portion of the reel is fastened to the top of the output shaft with a screw.
According to the present invention, the rotation of the drive shaft is transmitted to the output shaft in a considerably reduced state by at least two pairs of the reduction gear mechanisms contained in the motor case. Thus, it is not necessary to extremely increase the step number of the stepping motor itself. In virtue of this, the reel can be smoothly rotated although the reel is directly connected to the output shaft of the stepping motor. Since it is not necessary to increase the step number of the stepping motor, the rotor and the stator of the stepping motor may be downsized. Owing to this, the motor case as a whole is disposed inside the reel without increasing a diameter of the reel so that the whole of the symbol displaying unit may be effectively downsized.
BRIEF DESCRIPTION OF THE DRAWINGS
The above objects and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the invention when read in conjunction with the accompanying drawings, in which:
FIG. 1
is a front view showing a Japanese upright pinball machine using a symbol displaying unit according to the present invention;
FIG. 2
is an exploded perspective view of the symbol displaying unit;
FIG. 3
is a partially sectional view showing the symbol displaying unit;
FIG. 4
is a partially sectional view showing a stepping motor; and
FIG. 5
is a schematic illustration showing a structure of reduction gear mechanisms.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT (S)
FIG. 1
shows a Japanese upright pinball machine
2
to which a symbol displaying unit
5
is attached. The symbol displaying unit
5
is disposed at a game surface
3
of the pinball machine
2
. A start hole
6
is provided at a central portion of the game surface
3
. Besides the start hole
6
, the game surface
3
is provided with normal winning holes
7
, an openable plate
8
called as “attacker”, and an out hole
9
. Further, on the game surface
3
, are provided pins, rotary elements and so forth, although these are not shown. The symbol displaying unit
5
is for attracting interest of the pinball game, such as described below.
A game ball is shot up one by one toward the game surface
3
by a ball shooting unit. The shot game ball enters any of the start hole
6
, the normal winning hole
7
and the out hole
9
. When the openable plate
8
is opened, the game ball comes therein as well. In response to the game ball having entered the start hole
6
, the symbol displaying unit
5
is activated to simultaneously rotate reels thereof disposed behind a display window. The reels are arranged in a three-by-three matrix, and each of them is stopped after a proper period to display symbol combinations along judgment lines. These judgment lines are three vertical lines, three horizontal lines, and two diagonal lines. If a specific combination, for instance “7-7-7”, is displayed on any of the judgement lines, winning is obtained. When the winning occurs, the openable plate
8
is opened so that the game ball easily comes therein. While the symbol displaying unit
5
is activated, the game ball may enter the start hole
6
. This game ball is memorized as a reserved ball up to four, for example. When the reserved ball is memorized, the symbol displaying unit
5
is successively activated after one sequence of operations has been completed.
When the game ball enters any of the start hole
6
, the normal winning holes
7
and the openable plate
8
, a certain number of the game balls are paid out. Once the openable plate
8
is opened, this plate
8
is continued to be opened until a predetermined number of the game balls (for instance ten balls) come therein. The openable plate
8
is momentarily closed after the predetermined number of the game balls have come therein. After that, however, the openable plate
8
is successively opened again. This operation of the openable plate
8
is repeated within an extent of sixteen times. Accordingly, a large number of the game balls are obtained when the winning occurs on the symbol displaying unit
5
.
The symbol displaying unit
5
is attached to the game surface
3
of the pinball machine
2
so that the symbol displaying unit
5
should be extremely downsized in comparison with that used in a slot machine. For this reason, an outer diameter of the reel rotating behind the display window has a limitation of about 50 mm, for instance. Moreover, the respective reels should not be separately disposed from each other. Further, each of the reels needs an individual stepping motor for driving. In order to downsize the symbol displaying unit
5
, the stepping motor is required to be disposed inside the reel such as described later.
As shown in
FIG. 2
, symbols of “fruit”, “7” and so forth are arranged on a periphery of the reel
10
at predetermined intervals. The reel
10
is formed such that a symbol sheet
12
on which the symbols are printed is mounted on a reel body
11
which is made of a plastic as a single piece. Incidentally, the symbol displaying unit
5
includes nine reels and nine stepping motors having identical structures so that one pair of them is merely described below.
As shown in
FIGS. 3 and 4
, the stepping motor
14
includes a case
15
, a rotor
42
and a stator
43
. An output shaft
18
projects from a cover plate
19
covering one side of the case
15
. The stepping motor
14
is fixed to a support plate
22
by a screw
20
together with a motor board
21
. The support plate
22
is vertically provided. Thus, the output shaft
18
becomes horizontal and the reel
10
rotates around the horizontal output shaft
18
. A hub
24
for fixing the reel
10
is secured to the top of the output shaft
18
. Such as shown in
FIG. 3
, a screw
24
a
is used for securing the hub
24
to the output shaft
18
. However, the hub
24
may be tightly fitted with the output shaft
18
.
The reel body
11
has a cylindrical shape, a right side of which in the drawing is opened and a left side of which is integrally formed with a holding wall
25
having a recess of a step-like shape. A central portion of the holding wall
25
is formed with an opening
25
a
. Moreover, the central portion of the holding wall
25
is integrally formed with an attachment portion
26
protruding in a cup-like shape toward the other side of the reel body
11
. When the reel
10
is attached to the output shaft
18
in an axis direction, the attachment portion
26
is joined to the hub
24
so as to cover it. By the way, the holding wall
25
may be provided with an opening in order to lighten the reel
10
.
A periphery of the hub
24
is formed in a D-like shape so that a contour thereof is not circular. In accordance with the shape of the hub
24
, an inner shape of the attachment portion
26
is not circular as well. Owing to this, the reel
10
is fixed to the output shaft
18
so as not to be shifted in a rotational direction. It is needless to say that the hub
24
may be formed in an oval shape instead of the D-like shape. A screw
28
is inserted into the opening
25
a
of the holding wall
25
via washer
27
. Further, the screw
28
passes through a central hole of the hub
24
to be meshed with a female screw formed at the top of the output shaft
18
. In virtue of this, the reel
10
is fixed to the output shaft
18
relative to the axis direction. At the same time, almost all of the stepping motor
14
is disposed inside the reel
10
together with the case
15
.
If the top of the output shaft itself is formed in a D-like shape for attaching the reel thereto, it is possible to remove the hub
24
which is individually provided for the output shaft
18
. Meanwhile, in the case of using the hub
24
, an end side thereof may be formed with a female screw to be meshed with the screw
28
for fixing the reel
10
.
The periphery of the hub
24
is integrally formed with a projection
30
protruding in a radius direction of the hub
24
. The projection
30
is used for detecting one rotation of the output shaft
18
. To the cover plate
19
, is fixed a sensor supporting plate
31
extending parallel with the output shaft
18
. The sensor supporting plate
31
retains a photo sensor
32
comprising a light emitting element and a light receiving element. While the hub
24
is rotated in accordance with the rotation of the output shaft
18
, the projection
30
is detected at timing of passing through a space between the light emitting element and the light receiving element. Since the reel
10
is integrally rotated with the hub
24
, a timing signal obtained from the photo sensor
32
can be used as a signal representing that the reel
10
has passed a reference position every rotation. Incidentally, the attachment portion
26
of the reel
10
is formed with a slit
26
a
. In virtue of this, when the attachment portion
26
is fitted to the hub
24
, the projection
30
does not disturb it. As to the photo sensor
32
, it is possible to employ a reflection-type sensor.
The reel
10
is driven by the stepping motor
14
which is rotated in accordance with a number of drive pulses supplied thereto. The number of the drive pulses required for one rotation of the reel
10
is known in advance so that it is possible to recognize a rotational position of the reel
10
on the basis of a count value obtained from a counter counting the supplied number of the drive pulses. This counter is reset whenever the timing signal is detected. Kinds and order of the symbols arranged on the periphery of the reel
10
are also known in advance so that it is possible to recognize the kind of the displayed symbol on the basis of the counted value of the counter. Hence, it is possible to control winning occurrence on the symbol displaying unit by a microcomputer.
As described above, the hub
24
fixed to the output shaft
18
and rotated together with the reel
10
is integrally formed with the projection
30
. Owing to this, it is possible to adjust the reference position of the reel
10
relative to the rotational position of the stepping motor
14
by adjusting the position of the hub
24
in the rotational direction, in a state that the reel
10
is not attached to the output shaft
18
. Thus, the positional adjustment can be easily performed.
A back side of the photo sensor
32
is connected to a signal line
34
via a connector
33
. Wiring of the signal line
34
is performed along a wall of the case
15
with a clasp
35
disposed on this wall, so as not to disturb the rotation of the reel
10
. The signal line
34
is connected to connectors
36
and
37
fixed to the motor board
21
. Further, the signal line
34
is connected to a circuit unit provided on the motor board
21
.
As shown in
FIG. 4
, the inside of the case
15
is divided into a motor chamber and a gear chamber by a partition
40
through which a drive shaft
41
passes. Both ends of the drive shaft
41
are respectively supported by bearings so as to be rotatable. The rotor
42
is fixed to the drive shaft
41
, and the stator
43
is fixed to the inside of the case
15
so as to surround the rotor
42
. Structures of the rotor
42
and the stator
43
are well known from the foregoing Publication No. 9-266979 etc. so that detailed explanation thereof is omitted. In brief, the drive shaft
41
is rotated stepwise upon supplying the drive pulse to the stator
43
. In this embodiment, a step number of the drive shaft
41
is adapted to be “48”. In other words, the drive shaft
41
is adapted to be rotated by an angle of 7.5 degrees per drive pulse.
A drive gear
45
is fixed to the drive shaft
41
extended into the gear chamber. In the gear chamber, a transmission gear
48
is rotatably supported by bearings respectively provided on the cover plate
19
and the partition
40
. The transmission gear
48
is formed such that a larger gear
46
and a smaller gear
47
are unified so as to be coaxially rotated. Further, the output shaft
18
to which an output gear
49
is fixed is rotatably supported. As shown in
FIG. 5
, the small-sized drive gear
45
is meshed with the larger gear
46
, and the large-sized output gear
49
is meshed with the smaller gear
47
. In virtue of this gear structure, the rotation of the drive shaft
41
is transmitted to the output shaft
18
via two pairs of reduction gear mechanisms.
A teeth number of the drive gear
45
is ten. A teeth number of the larger gear
46
is twenty five. A teeth number of the smaller gear
47
is ten. A teeth number of the output gear
49
is thirty. Accordingly, a total reduction ratio of these gears is expressed as follows:
(10/25)×(10/30)=(1/7.5)
This means that the output shaft
18
is rotated by a 1° angle upon rotating the drive shaft
41
by a 7.5° angle. Thus, even though the unit step angle of the drive shaft
41
is set to the 7.5° angle by the rotor
42
and the stator
43
, the reel
10
is smoothly rotated because a unit step angle of the output shaft
18
is reduced to the 1° angle. The step rotation of the reel
10
is adapted to be almost inconspicuous when the reel
10
is rotated at a low speed. In addition, the reel
10
is directly connected to the output shaft
18
so that a rotational axis of the reel
10
is prevented from being biased even if the reel
10
is continuously used.
When fixing the reel
10
to the output shaft
18
, it is possible to secure the reel
10
in the rotational direction and in the axis direction only by fastening the attachment portion
26
to the hub
24
with the screw
28
. Moreover, fixing the reel
10
is efficiently performed. When the kinds and the arrangement of the symbols are changed for the purpose of remodelling, it is simply required to attach another reel
10
after taking off the screw
28
. This operation is very easy.
In the above embodiment, the reduction ratio of “1/7.5” is obtained from the two pairs of the reduction gear mechanisms. The teeth numbers of the gears may be properly changed, and the reduction gear mechanisms of three pairs or more may be provided in the gear chamber. Moreover, the present invention is not exclusive to the symbol displaying unit attached to the pinball machine. The present invention is applicable to a slot machine and the other game machines having similar structure.
Although the present invention has been fully described by way of the preferred embodiments thereof with reference to the accompanying drawings, various changes and modifications will be apparent to those having skill in this field. Therefore, unless otherwise these changes and modifications depart from the scope of the present invention, they should be construed as included therein.
Claims
- 1. A symbol displaying unit used for a game machine, said symbol displaying unit rotating a reel on which a plurality of symbols are arranged, and any of said symbols being displayed when said reel is stopped, said symbol displaying unit comprising:a stepping motor for rotating said reel; a motor case of said stepping motor, said motor case being disposed inside said reel; an output shaft of said stepping motor projecting toward the outside of said motor case, said output shaft being fixed to said reel; first and second reduction gear mechanisms contained in said motor case, said first and second reduction gear mechanisms transmitting rotation of a drive shaft of said stepping motor to said output shaft of said stepping motor in a reduced state.
- 2. A symbol displaying unit according to claim 1, wherein an end of said output shaft has a reel attaching portion whose contour is a non-circular shape, and one side of said reel has an attachment portion whose inner shape corresponds to the contour of said reel attaching portion, said attachment portion being fitted with said reel attaching portion to fix said reel in a rotational direction.
- 3. A symbol displaying unit according to claim 2, wherein said attachment portion of said reel is fastened to the end of said output shaft with a screw to fix said reel in an axis direction.
- 4. A symbol displaying unit according to claim 3, wherein said first reduction gear mechanism comprises a drive gear fixed to said drive shaft of said stepping motor and a first gear meshing with said drive gear, andsaid second reduction gear mechanism comprises an output gear fixed to said output shaft of said stepping motor and a second gear meshing with said output gear, wherein said first gear is larger than said drive gear and said second gear is smaller than said output gear.
- 5. A symbol displaying unit according to claim 4, wherein a teeth number of said first gear is greater than a teeth number of said second gear.
- 6. A symbol displaying unit according to claim 5, wherein said first gear and said second gear are coaxially rotated.
- 7. A symbol displaying unit according to claim 6, wherein said first gear and said second gear are unified.
- 8. A symbol displaying unit according to claim 7, further comprising:a partition for dividing the inside of said motor case, said reduction gear mechanisms being contained in a gear chamber formed by said partition.
- 9. A symbol displaying unit according to claim 2, further comprising:a projection integrally rotated with said output shaft of said stepping motor; a sensor for detecting said projection, said sensor detecting one rotation of said output shaft; and a sensor supporting member to which said sensor is fixed, said sensor supporting member extending in parallel with said output shaft.
- 10. A symbol displaying unit according to claim 9, wherein said sensor supporting member is provided on a side face of said motor case from which said output shaft protrudes.
- 11. A symbol displaying unit according to claim 10, wherein said projection is integrally formed with said reel attaching portion of said output shaft.
- 12. A symbol displaying unit according to claim 11, wherein said sensor is a photo sensor.
US Referenced Citations (11)
Foreign Referenced Citations (2)
Number |
Date |
Country |
6-39085 |
Feb 1994 |
JP |
9-266979 |
Oct 1997 |
JP |