JP4964640B2 - Bullet ball machine - Google Patents

Description

  The present invention relates to a ball game machine including a shielding device that can be displaced into an open state in which a display area capable of displaying identification information is opened and a shielding state in which shielding is performed.

In a ball game machine (pachinko machine), a display device (symbol display device) capable of variably displaying identification information composed of numbers and symbols is attached to the rear side of the game board, and the identification displayed on the display device Information can be visually recognized from the display window (transparent window portion) of the center accessory (large decorative member) provided in the approximate center of the game board. Then, between the display window on the game board and the display device, when the gaming state becomes a predetermined state, the display window is shielded to conceal the identification information, etc. so as to enhance the effect effect during the game. An apparatus is provided (see, for example, Patent Document 1).
JP 2004-135585 A

  However, the shielding device in the above-described ball game machine has a moving stroke corresponding to the size of the display window from the upper end to the lower end of the display window and vice versa with the power of a motor or the like. Since the display window is opened and closed only by moving up and down, if the display window becomes larger as the display screen becomes larger, the opening and closing movement stroke of the shielding plate becomes longer, and the display window is often opened and closed. It may take time and interfere with the game. In addition, if the opening / closing operation of the shielding plate is speeded up to shorten the opening / closing time, a large burden is placed on the motor, the shielding plate, etc., which may cause an early failure.

  In view of the above-described conventional problems, an object of the present invention is to provide a ball game machine that can quickly open and close a display window without imposing a heavy burden on a motor or a shielding plate.

According to the present invention, the above problem is solved as follows.
(1) A display device capable of displaying identification information relating to a game in a display area, a game board having a circular display window provided in front of the display area and allowing the identification information to be visually recognized, and the display window In a ball game machine comprising an open state that opens and a shielding device that can be displaced into a shielding state that shields part or all of the display window, the shielding device includes a motor that can rotate forward and backward, and the display window A rotating plate that is disposed immediately behind the rotating plate and is rotatable by a predetermined angle around a virtual rotating shaft that is directed in the front-rear direction by the power of the motor, and is pivotally supported by a supporting shaft around the rotating plate, and the outer periphery of the rotating plate A shielding position that rotates integrally with a sector gear that meshes with the external teeth provided on the shielding plate and shields part or all of the display window from an open position that opens the display window in synchronization with the rotation of the rotating plate; And vice versa A plurality of movable shield plates, and the respective sector gears adjacent to each other in the circumferential direction of the rotating plate are provided with flanges that can alternately contact the front surface and the rear surface of the external teeth on the rotating plate. Provide.

(2) In the above item (1), the rotating plate is formed of a transparent or translucent synthetic resin material.

(3) In the above item (1) or (2), the outer periphery of the rotating plate or the vicinity thereof is arranged in the front-rear direction around the rotating plate so that the rotating plate can rotate around the virtual rotation axis. A holding member for clamping is provided.

(4) In any one of the above items (1) to (3), the shielding plates adjacent to each other in the circumferential direction of the rotating plate are arranged so as to be alternately superimposed on the front and rear.

According to the present invention, the following effects can be obtained.
According to the first aspect of the present invention, since the plurality of shielding plates are simultaneously rotated from the open position to the shielding position and vice versa in synchronization with the rotation of the rotating plate, the display window is opened and closed quickly. Can be opened and closed. In addition, the sector gears adjacent to each other in the circumferential direction of the rotating plate are provided with flanges that can alternately come into contact with the front and rear surfaces of the external teeth of the rotating plate, thereby rattling the front and rear of the rotating plate. Can be held by each flange to ensure the engagement between each sector gear and the external teeth of the rotating plate.

  According to the second aspect of the present invention, since the rotating plate is formed of a transparent or translucent synthetic resin material, the identification information displayed on the display device can be viewed through the rotating plate.

  According to the third aspect of the present invention, the rotating plate can be reliably supported by the pressing member so as to be able to rotate around the virtual rotation axis.

  According to the invention described in claim 4, by arranging the shielding plates adjacent to each other in the circumferential direction of the rotating plate so as to alternately overlap in the front-rear direction, the plurality of shielding plates are effectively arranged in a narrow space. Can do.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a ball game machine to which an embodiment of the present invention is applied, and FIG. 2 is a perspective view of the ball game machine with a game board removed from a game machine frame. In the following description, the front side of the drawing in FIG. 1 is “front or front”, the back side of the drawing is “back or back”, the left is “left”, and the right is “right”. .

  As shown in FIGS. 1 and 2, the ball game machine 1 includes a gaming machine frame 2 installed on a gaming island of a gaming facility such as a gaming store, and identification information 100 (FIG. 1 only). A display device 3 capable of variably displaying, a game board 4 which will be described later on the front surface of the display device 3 and disposed in front of the display device 3, and a circular glass plate 61 is fitted in the center, A front door 6 is pivotally attached to a left portion of the gaming machine frame 2 by an up and down hinge shaft (not shown), and a handle 7 provided at a lower right front portion of the gaming machine frame 2 is rotated. Thus, a predetermined game can be performed by driving a game ball stored in a ball storage tray 8 provided below the front door 6 into a game area 4 from a launching device (not shown).

  The game board 5 is formed of an opaque material such as veneer plywood, and a circular (including elliptical) game area 4 surrounded by the guide rails 9 and 10 is formed on the board surface (front surface). A circular display window 12 is provided at a substantially central portion of the game area 4. The display window 12 is formed by a center accessory 13 described later.

  The game area 4 includes a large number of game nails 11 for changing the flow direction of game balls, a center member 13 made of synthetic resin, a normal symbol operation gate 14 through which a game ball can pass or enter, and a game A plurality of winning holes 15 into which balls can enter, a symbol start port 16 into which gaming balls can enter, a first state that is disadvantageous for the player (a closed state in which the gaming balls are substantially incapable of winning) and the player A large winning device 17 that can be displaced to a second state (open state in which a game ball can win a prize) advantageous to the player is arranged. Further, at the lowermost part of the game area 4, there is provided an out port 18 for discharging the game ball driven into the game area 4 to the rear of the game board 5, and further to the right side of the center accessory 13 in the game area 4. The auxiliary display window 51 is perforated.

The game ball launched from the launching device is guided by the guide rails 9 and 10, is driven into the game area 4, and flows down while coming into contact with the game nail 11, and enters either the winning opening 15 or the symbol start opening 16. In such a case, a predetermined number of game balls are awarded to the player as prize balls, and if none of them is entered, it is discharged from the out port 18 to the rear of the game board 5.

  The display device 3 has a display area 301 composed of a liquid crystal screen or the like on the front surface, and is fixed to the gaming machine frame 2 so that the display area 301 faces the back surface of the game board 5. The identification information 100 displayed in the display area 301 is variably displayed for a predetermined time based on a predetermined probability when the game ball that has been driven into the game area 4 enters the symbol start port 16 and then stops. Is displayed. When the combination of the identification information 100 that is confirmed and displayed is a predetermined display mode, for example, as shown in FIG. 1, when three identical numbers “7” are arranged, a specific gaming state (so-called big hit state) ) Is generated, and the big prize device 17 is displaced from the first state to the second state, and a predetermined game value is given to the player.

The gaming board 5 can be attached to and detached from the gaming machine frame 2 with the display device 3 attached to the gaming machine frame 2 by being arranged in front of the display device 3. As a result, the gaming theme of the gaming machine 1 can be easily changed by removing the gaming board 5 and the various parts attached to the gaming board 5 from the gaming machine frame 2 and replacing them with a new gaming board 5. The display device 3 can be reused while attached to the gaming machine frame 2.

  The center accessory 13 is fixed to the game board 5. The circular display window 12 provided in the center accessory 13 enables the identification information 100 displayed in the display area 301 to be viewed from the front of the gaming machine 1. A transparent plate 121 is provided on the rear side of the display window 12.

Below the display window 12 in the center accessory 13, among the game balls that have been driven into the game area 4, the game balls that have entered the warp inlet 134 provided on the left side of the center accessory 13 are turned left and right and back and forth. A stage 131 that can be moved is formed, and a game ball that has entered a drop opening 132 provided at the center rear of the stage 131 among the game balls that have rolled the stage 131 is also started on the lower front surface of the stage 1301. A discharge port 133 that discharges right above the port 16 is provided. Note that the game ball discharged from the discharge port 133 is discharged directly above the symbol start port 15, so that the probability of entering the symbol start port 16 is high.

  The auxiliary display window 51 is provided in a region where a game ball that is driven into the game region 4 does not flow down and at a position facing the right region of the display region 301 in the display device 3, and displays auxiliary information displayed in the display region 301. Visible. The auxiliary information assists the display of the identification information 100 and enhances the effect. Thus, the identification information 100 is displayed in the center area of the display area 301 facing the display window 12, and the auxiliary information is displayed in the right area of the display area 301 facing the auxiliary window 51, thereby providing a single display. With the device 3, the effect information can be viewed from the display window 12, and the auxiliary information can be viewed from the auxiliary display window 51.

  As shown in FIG. 5, on the back surface of the game board 5, via the upper set plate 19, the display window 12, that is, the display area 301 is opened (see FIGS. 1 and 3) and shielded (see FIG. 5). 4), a displaceable shielding device 20 is attached.

As described above, since the display device 3 is disposed on the gaming machine frame 2 side and the shielding device 20 is disposed on the game board 5 side, it is necessary to consider the mounting relationship of the display device 3 to the game board 5 as in the past. Since there is no property, the display window 12 can be enlarged.

A lower set plate 21 is attached below the upper set plate 19. The lower set 21 is integrally formed with a discharge path 211 for discharging game balls that have entered the winning holes 15 and the symbol start port 16 to the rear side of the game board 5, and the front surface of the game board 5. A printed circuit board 42 mounted with LEDs for illuminating is attached. In addition, you may fix the shielding apparatus 20 directly to the back surface of the game board 5 without the upper set board 19 as needed.

The upper set board 19 is made of a translucent or transparent synthetic resin, and is fixed to the back surface of the game board 5 by a plurality of bolts (not shown) so as to surround the rear side periphery of the center accessory 13. . As shown in FIG. 7, the upper set plate 19 has an opening 191 that overlaps backward with respect to the display window 12 of the center accessory 13 and does not hinder the visual recognition of the identification information 100 from the display window 12. A plurality of (four in the present embodiment) columnar attachment portions 192 for projecting a predetermined amount rearward and supporting the shielding device 20 are integrally provided.

  As shown in FIGS. 6 and 7, the shielding device 20 rotates at a predetermined angle around a metal base plate 23, a motor 24, and a virtual rotation axis O that faces the front-rear direction via the relay gear 25 by the rotation of the motor 24. A possible rotating plate 26, six (even number) sector gears 28 to 33 pivotally supported at respective positions by a support shaft 27 facing the base plate 23 in the front-rear direction, and the sector gears 28 to 33 rotate integrally with each other. Six movable shielding plates 34 to 39 are provided.

When the shielding device 20 is in the open state, the display window 12 is opened so that the identification information 100 can be viewed from the display window 12, and when the shielding device 20 is also in the shielded state, the display window 12 is shielded. The identification information 100 is concealed so that the identification information 100 cannot be viewed from the display window 12.

All movable parts of the motor 24, the relay gear 25, the rotating plate 26, the sector gears 28 to 33 and the shielding plates 34 to 39 in the shielding device 20 are arranged on the front side of the base plate 23 facing the back surface of the game board 5. Accordingly, since all the movable parts do not protrude rearward from the base plate 23 that is a fixed part, a situation in which the movable part comes into contact with the display area 301 of the display device 3 and the display area 301 is damaged. It can be surely prevented.

In the present embodiment, the sector gears 28 to 33 and the shielding plates 34 to 39 are formed separately, but the sector gears 28 to 33 and the shielding plates 34 to 39 may be integrally formed. Further, the rotation of the motor 24 may be directly transmitted to the rotating plate 26 without using the relay gear 25.

  The base plate 23 has a circular opening 231 at the center, and the opening 231 is substantially aligned rearward with respect to the display window 12 of the center accessory 13, and a predetermined amount is provided between the front surface and the rear surface of the game board 5. Are fixed to the mounting portion 192 of the upper set plate 19 by the bolts 22 so that a gap is formed. Accordingly, the motor 24, the relay gear 25, the rotating plate 26, the sector gears 28 to 33, and the shielding plates 34 to 39 attached to the front surface of the base plate 23 do not interfere with the rear part of the center accessory 13. As a result, the depth dimension of the stage 131 in the center accessory 13 can be increased, and various movements of the game ball can be made, so that the fun of the game can be further improved.

  The rotating plate 26 is formed into a disk shape by a transparent or translucent acrylic resin plate, and is aligned with the rear of the display window 12 and faces the front-rear direction substantially matching the center of the display window 12. It is supported by the base plate 23 so that it can rotate around the center. Thereby, even if the rotating plate 26 is arranged so as to be aligned with the display window 12, the rotating plate 26 does not block the visual recognition of the identification information 100 from the display window 12.

On the outer periphery of the rotary plate 26, external teeth 261 that can be engaged with the sector gears 28 to 33 and four arm portions 262 to 265 projecting in the radial direction are provided.

  An outer tooth 262 a that meshes with a small gear 251 provided integrally with the relay gear 25 is provided on the outer peripheral edge of the upper left arm portion 262. The external teeth 262a may be provided on the outer periphery of the rotating plate 26.

  The outer peripheral edge of the upper left arm portion 262 is provided by a pressing member 44 rotatably provided on a shaft 43 for pivotally supporting the relay gear 25 on the base plate 23, and the outer peripheral edge of each arm portion 263 to 265 is a base. It is clamped in the front-rear direction by each pressing member 40 rotatably provided on each shaft 41 facing the front-rear direction fixed to the play 23. Thereby, the rotating plate 26 is supported by the base plate 23 so as to be able to rotate at a predetermined angle around the virtual rotation axis O so as not to rattle in the front-rear direction.

The holding member 40 for supporting the rotating plate 26 so as to be able to rotate around the virtual rotation axis O is rotated instead of sandwiching the outer periphery of each of the arm portions 262 to 265 provided on the rotating plate 26. You may make it clamp the outer periphery of the board 26 directly in the front-back direction.

Around the rotating plate 26 in the base plate 23, six support shafts 27 facing in the front-rear direction for rotatably supporting the sector gears 28 to 33 and the shielding plates 34 to 39 on the base plate 23 are fixed at equal intervals. Yes.

The sector gears 28 to 33 and the shielding plates 34 to 39 are integrally rotatable, are rotatably supported by the respective support shafts 27, and are point-symmetric with respect to the virtual rotation axis O of the rotation plate 26. It is arranged to become.

The sector gears 28 to 33 are respectively meshed with the respective external teeth 261 of the rotating plate 26, and are synchronized with the rotation of the rotating plate 26 from the open position shown in FIG. 8 to the shielded position shown in FIGS. Rotate all at once in the same direction around the pivot 27.

Mainly as shown in FIGS. 12 to 14, the arcuate outer peripheral edges of the sector gears 28 to 33 are provided with flanges 28 a to 33 a that can alternately contact the front surface or the rear surface of the external teeth 261 of the rotating plate 26, respectively. Is provided. Specifically, the sector gears 28, 30, and 32 are provided with flange portions 28 a, 30 a, and 32 a that can contact the rear surface of the external teeth 261, and the sector gears 29, 31, and 33 are provided with the external teeth 261. There are provided flanges 29a, 31a, 33a that can come into contact with the front surface. In other words, the sector gears 28 to 33 adjacent to each other in the circumferential direction of the rotating plate 26 have flanges 28a to 33a that can alternately come into contact with the front and rear surfaces of the external teeth 261 in the rotating plate 26. Provided. Thereby, the backlash of the rotating plate 26 in the front-rear direction can be suppressed, and the engagement between the sector gears 28 to 33 and the external teeth 261 of the rotating plate 26 can be ensured.

The shielding plates 34 to 39 are substantially bow-shaped in front view, and in synchronization with the rotation of the rotating plate 26, together with the sector gears 28 to 33, from the open position shown in FIG. 8 to the shielding position shown in FIGS. On the other hand, they rotate simultaneously in the same direction around the pivot 27. In addition, the shielding plates 34 to 39 adjacent to each other in the circumferential direction of the rotating plate 26 are arranged so as to be alternately superimposed on the front and rear. Specifically, the shielding plates 34, 36, and 38 are disposed so as to overlap the front sides of the shielding plates 35, 37, and 39. Accordingly, the plurality of shielding plates 34 to 39 can be effectively arranged in a narrow space without causing the shielding plates 34 to 39 to interfere with each other.

  When the shielding plates 34 to 39 are in the open position, the swinging end of the shielding plates 34 to 39 is retracted to the outside of the rotating plate 26 so that the identification information 100 is visually recognized from the display window 12. Further, when it is in the shielding position, the swinging end portion is located in the vicinity of the virtual rotation axis O, and the display window 12 is shielded except for the vicinity of the center thereof. Visibility is disabled. Thereby, since each shielding board 34-39 can open and close the display window 12 by rotating simultaneously only the movement stroke substantially equivalent to the radius of the display window 12 and the rotation board 26, the motor 24, each It is possible to quickly open and close the display window 12 while reducing the burden on the shielding plates 34 to 39.

Further, since the sector gears 28 to 33 and the shielding plates 34 to 39 are arranged so as to be point-symmetric with respect to the virtual rotation axis O of the rotating plate 26, each shielding plate 34 is increased with an increase in the size of the display window 12. Even if .about.39 is increased, each of the shielding plates 34 to 39 can be quickly rotated to each position with a small force by the small motor 24 with a small output.

That is, when the sector gears 28 to 33 and the shielding plates 34 to 39 are arranged so as to be point symmetric with respect to the virtual rotation axis O of the rotating plate 26, the rotational moment due to its own weight is caused between the shielding plates in the point symmetric positions. Act in opposite directions. Thus, as shown in FIG. 8, when the shielding device 20 is in an open state, for example, a rotational moment due to its own weight acts on the shielding plate 35 counterclockwise (arrow A direction) about the support shaft 27. In addition, a rotational moment due to its own weight acts on the shielding plate 38 that is point-symmetric with respect to the shielding plate 35 in the clockwise direction (in the direction of arrow B) about the support shaft 27. The rotation moment acting on the shielding plate 35 is transmitted to the rotation plate 26 via the sector gear 29 so as to act clockwise (arrow C direction), and the rotation moment acting on the shielding plate 38 is Then, it is transmitted via the sector gear 32 so as to act counterclockwise (arrow D direction) with respect to the rotating plate 26. As a result, the rotational moments transmitted to the rotating plate 26 cancel each other, so the rotating plate 26 is rotated by the small motor 24 with a small output, and the shielding plates 34 to 39 are lightly moved to the open position and the shielding position. It can be quickly rotated by force.

7 to 10, 45 is a sensor that detects the open position of the shielding plate 39. When the sensor 45 detects the open position of the shielding plate 39, the power supply to the motor 24 is stopped.

  Next, operation | movement of the shielding apparatus 20 in this embodiment is demonstrated. As shown in FIG. 8, when the shielding device 20 is in the open state, the shielding plates 34 to 39 are in the open position, and as shown in FIGS. 12, the identification information 100 displayed in the display area 301 is visible.

  When the motor 24 rotates forward from the open / closed state, the rotation is transmitted to the rotating plate 26 via the relay gear 25. The rotary plate 26 rotates around the virtual rotation axis O by a predetermined angle (an angle corresponding to the number of external teeth 262a of the arm portion 262) from the open position shown in FIG. In synchronization with this, all the shielding plates 34 to 39 are simultaneously rotated from the open position toward the virtual rotation axis O via the sector gears 28 to 33 and stopped at the shielding position. Then, as shown in FIG. 4, the display window 12 is shielded, and the identification information 100 displayed in the display area 21 is shielded.

  Further, when the motor 24 rotates in the reverse direction from the shielded state, the rotation is transmitted to the rotating plate 26 via the relay gear 25. The rotating plate 26 rotates about a virtual rotation axis O from the shielding position shown in FIG. In synchronism with this, all the shielding plates 34 to 39 are simultaneously rotated from the shielding position toward the outer periphery of the rotating plate 26 via the sector gears 28 to 33 and stopped at the open position. 12 is released.

As an opportunity to open and close the shielding device 20, for example, the gaming state is a reach state (two pieces of identification information 100 are confirmed and displayed with the same design, and the remaining one piece of identification information 100 is the two pieces of identification information. If it is confirmed and displayed with the same design as 100, a state where there is a possibility of a big hit is possible. In such a case, when the gaming state becomes the reach state, the respective shielding plates 34 to 39 are moved from the open position to the shielding position, and the identification information 100 displayed in the display area 301 is shielded and cannot be visually recognized. And Then, after the predetermined time has elapsed, when the last piece of identification information 100 is stopped and confirmed and displayed, the respective shielding plates 34 to 39 are rotated from the shielding position to the open position, and the identification that has been shielded until then is performed. By making the information 100 suddenly visible, it is possible to enhance the effect of reaching at the time of reaching.

As mentioned above, although one Embodiment of this invention was described, it is possible to give the following various deformation | transformation and change with respect to this Embodiment within the range which does not deviate from the summary of this invention.
(I) When the shielding plates 34 to 39 are in the shielding position, the entire area of the display window 12 is shielded.
(Ii) The number of the shielding plates 34 to 39 is appropriately changed. In this case, it is preferable to use an even number.

1 is a front view of a ball game machine to which an embodiment of the present invention is applied. It is a perspective view of a bullet ball game machine in a state where the game board is removed from the game machine frame. It is a front view of a game board when a shielding apparatus exists in an open state. It is a front view of a game board when a shielding apparatus is in a shielding state. It is a back view of a game board when a shielding apparatus is in a shielding state. It is a disassembled perspective view of the shielding apparatus seen from diagonally forward. It is a disassembled perspective view of the shielding apparatus seen from diagonally back. It is a front view of the shielding apparatus when it exists in an open state. It is a front view of the shielding apparatus when it exists in a shielding state. It is a reverse view of the shielding apparatus in a shielding state. It is a longitudinal cross-sectional schematic diagram in alignment with the XI-XI line in FIG. It is an enlarged front view of the principal part. FIG. 13 is a vertical sectional view taken along line XIII-XIII in FIG. 12. It is the XIV-XIV line longitudinal cross-sectional view in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ball game machine 2 Game machine frame 3 Display apparatus 4 Game area 5 Game board 6 Front door 7 Handle 8 Ball storage tray 9, 10 Guide rail 11 Game nail 12 Display window 13 Center accessory 14 Normal symbol operation gate 15 Winning mouth 16 Symbol starting port 17 Large winning device 18 Out port 19 Upper set plate 20 Shielding device 21 Lower set plate 22 Bolt 23 Base plate 24 Motor 25 Relay gear 26 Rotating plate 27 Shafts 28-33 Sector gears 28a-33a Hooks 34-39 Shielding Plate 40 Holding member 41 Shaft 42 Printed circuit board 43 Shaft 44 Holding member 45 Sensor 51 Auxiliary display window 61 Glass plate 100 Identification information 121 Transparent plate 131 Stage 132 Drop port 133 Discharge port 134 Warp port 191 Opening 192 Mounting portion 211 Discharge path 231 Opening 251 Small gear 261 External teeth 262 to 265 Arm 62a outer teeth 301 display area O imaginary rotation axis

Claims (4)

A display device capable of displaying identification information relating to a game in a display area, a game board having a circular display window provided in front of the display area and allowing the identification information to be visually recognized, and an opening for opening the display window In a ball game machine comprising a state and a shielding device that can be displaced to a shielding state that shields part or all of the display window,
The shielding device includes a motor that can rotate forward and backward, a rotating plate that is disposed directly behind the display window and that can rotate by a predetermined angle around a virtual rotating shaft that is directed in the front-rear direction by the power of the motor, and the rotating plate It is pivotally supported by each support shaft on the periphery, and rotates integrally with a sector gear meshing with external teeth provided on the outer periphery of the rotating plate, and the display window is opened in synchronization with the rotation of the rotating plate. A shielding position that shields a part or all of the display window from the open position, and a plurality of shielding plates that can be simultaneously rotated to the reverse,
A ball game machine characterized in that the sector gears adjacent to each other in the circumferential direction of the rotating plate are provided with flanges that can alternately come into contact with the front and rear surfaces of the outer teeth of the rotating plate. . 2. The ball game machine according to claim 1, wherein the rotating plate is made of a transparent or translucent synthetic resin material. A pressing member that clamps the outer periphery of the rotating plate or its vicinity in the front-rear direction is provided around the rotating plate so that the rotating plate can rotate around the virtual rotation axis. A bullet ball game machine according to 1 or 2.   The ball game machine according to any one of claims 1 to 3, wherein the shielding plates adjacent to each other in the circumferential direction of the rotating plate are arranged so as to be alternately superimposed on the front and rear.

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