JP2008237751A - Game machine and game nail - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent cracks on the surface of a game board when the surface is cleaned with alcohol in a game machine comprising the resin game board. <P>SOLUTION: The game board of the pachinko machine is formed of acrylic, and a lower hole 242h is bored so that a game nail 10 is driven into the hole. A knurled part 12 whose diameter d2 is larger than the shank diameter d1 is formed at the distal end of the game nail 10. The knurled part has four thread crest parts 15 at 90-degree intervals around the axis on the outer periphery. The torsion angle of each thread crest part 15 is 180 degrees, and the apex of the crest is roundly chamfered. The diameter Dh of the lower hole 242h is at least d1 but smaller than d2. The game nail is driven into the lower hole 242h in such a state that the border between the knurled part 12 and a shank part 13 is buried in the lower hole 242h. As the apexes of the thread crest parts 15 are roundly chamfered, generation of stress or notches in the lower hole 242h when the game nail is driven into the hole can be prevented, and cracks can be prevented even if alcohol infiltrates. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gaming machine that launches a game ball and wins a winning opening provided on a game board surface, and more particularly to a structure for fixing a game nail to a resin game board in such a gaming machine.

  There are a pachinko machine and a smart ball as a gaming machine that allows a game ball launched on the game board surface to win a predetermined winning opening. In these gaming machines, game nails are driven into the game board surface as obstacles to the game balls flowing down the game board surface. Conventionally, veneer boards have been mainly used for game boards, but recently, it has also been proposed to use resins (see Patent Documents 1 to 3). Resin game boards, especially those made of transparent resin using acrylic resin, polycarbonate resin, etc., are equipped with a decoration unit on the back side of the game board. There is an advantage that the production can be realized.

  In the case of using a resin game board, it is usual to drive a game nail after making a pilot hole in advance in order to avoid breaking the game board. Patent Documents 1 to 3 disclose a technique for forming a knurled portion for retaining a game nail over a portion corresponding to the depth of the prepared hole in order to make it difficult to remove the game nail driven into the drilled prepared hole. ing.

JP 2000-84162 A JP 2005-204862 A Utility Model Registration No. 3116027

  It is desirable that the surface of the game board be cleaned regularly to avoid the appearance of the gaming machine from deteriorating the interest. The dirt on the surface of the game board may affect the movement of the game ball. Periodic cleaning is also desired in order to be able to play an appropriate game. The game board is often cleaned by wiping the surface with alcohol. This is because the game board is often used in a state where it is installed in the hall, and is effective in wiping off dirt such as cigarette dust adhering to the surface.

  However, if the surface of the acrylic resin game board is wiped with alcohol, the game board may crack at the base of the game nail. FIG. 7 is a photograph of cracks generated during cleaning. A game nail N is driven into a game board B made of acrylic resin. As a result of wiping the surface of the game board B with alcohol, a crack SC generated at the base of the game nail N is shown. Such a crack impairs the appearance of the game board B, affects the movement of the game ball, and causes various adverse effects such as reducing the holding power of the game nail N.

  In general, it is known that a crack called a solvent crack is generated by using an alcohol or other organic solvent for a thermoplastic resin including an acrylic resin. The cracks shown in FIG. 7 are also considered to be one type of this, but since the application history of resin materials to game boards has been shallow, measures to deal with such problems have not been fully studied, and the effect of replacing alcohol The current situation is that no cleansing agents are available. If the crack is a solvent crack, it is not a phenomenon peculiar to the combination of acrylic resin and alcohol, but a phenomenon that can be caused by a combination of various resin game boards and organic solvents. In view of such a problem, an object of the present invention is to suppress the occurrence of cracks during cleaning with an organic solvent by devising a structure for fixing a game nail to a resin game board.

  The present invention is directed to a gaming machine that allows a game ball to win a predetermined winning opening. Examples of such gaming machines include pachinko machines and smart balls. The gaming machine of the present invention includes a resin gaming board on which gaming balls flow down. For example, a game board made of acrylic or polycarbonate can be used. The game board has a winning opening. In addition, game nails having the following shapes are driven into the game board as obstacles flowing down.

  The game nail of the present invention has a body part, a head part, and a knurl part. The body portion has a cylindrical shape with a predetermined body diameter. The head is a plate-shaped part that is formed once in the body part and has a diameter larger than the body diameter. Various shapes such as a flat plate shape and a hemispherical shape can be adopted. The knurled part is a part formed at the other end of the body part and driven into the game board. In the knurled portion, a spiral ridge is formed on the outer periphery. The top of the ridge is chamfered to an obtuse angle or a curved surface.

  When the game nail of the present invention is driven, the game nail is sufficiently firmly held so that the spiral ridges bite into the game board. In this state, generation of cracks when the surface is wiped with an organic solvent is suppressed. Although the reason why such an effect occurs has not been completely elucidated, it is presumed that it is due to the following action in view of the mechanism by which the solvent crack occurs. First, the game nail of the present invention has a chamfered crest, so that it is possible to suppress the formation of a sharp notch in the prepared hole surface of the game board when biting. Moreover, as a result of suppressing the formation of such notches, the stress concentration generated at the tip can also be relaxed, and the residual stress in the portion where the ridges bite can be relaxed. Solvent cracks are said to occur when a resin in which stress remains remains in contact with an organic solvent. Solvent cracks tend to occur at sites where stress is high, such as the tip of a notch. The game nail of the present invention can suppress the generation of cracks because it can suppress the occurrence of notches and can also reduce the stress concentration there.

  Although the above-mentioned ridge part can take various shapes, it is preferable that the twist angle from once to the other end of the knurl part is formed to be 180 degrees or less. The torsion angle refers to the rotation angle around the axis of the game nail from the start point to the end point of the ridge. The game nail rotates around the axis when driven due to the hilly portion being formed in a spiral shape, but excessive rotation of the game nail can be suppressed by suppressing the torsion angle of the hilly portion to 180 degrees or less. . As a result, the stress generated in the game board at the time of driving can be suppressed, and the occurrence of cracks can be suppressed.

  The above-described action can be obtained by making the ridge part parallel to the axis of the game nail. That is, when the game nail is viewed from the side, it is obtained by increasing the inclination angle of the ridge with respect to the cross section orthogonal to the axis of the game nail. In order to relieve the stress at the time of driving, the ridges may be formed so that the inclination angle becomes approximately 60 degrees or more regardless of the twist angle described above.

  The number of the game nail may be only one, but it may be a plurality of lines, that is, a plurality of game nails may be formed at predetermined intervals along the outer periphery of the knurled portion. By using multiple strips, it is possible to hold the game nail firmly with the game board while suppressing stress during driving.

  In the case where the ridges are multi-striped, it is preferable that the valleys between the ridges and the ridges are concave curved surfaces. By doing so, it is possible to avoid the formation of corners at the boundary between the ridges and valleys, and to suppress excessive deformation of the game board when driven. In addition, the degree of adhesion between the game board and the surface of the game nail can be increased. As a result, stress generated in the game board can be suppressed, and occurrence of sharp notches in the game board at the time of driving can be suppressed. In addition, when the surface is wiped with an organic solvent, the organic solvent can be prevented from touching the prepared hole portion of the game board in which the knurled portion is driven. The occurrence of cracks can be suppressed by at least some of these actions.

  The diameter of the knurled portion can be arbitrarily set, but is preferably equal to or larger than the body diameter. By doing so, the entire knurled portion can be brought into close contact with the game board when driven into the game board. As a result, the organic solvent can be prevented from touching the prepared hole portion of the game board in which the knurled portion has been driven, and the occurrence of cracks can be suppressed. In order to sufficiently obtain such an effect, it is more preferable that the minimum diameter of the knurled part is not less than the trunk diameter.

  The present invention can be configured as a single game nail, or can be configured as a gaming machine in which the game nail is driven into a resin game board. Although various resin materials can be applied to the game board, the present invention is particularly useful when a thermoplastic resin is used. This is because the thermoplastic resin has the property of easily causing cracks due to brittle fracture. From the viewpoint of ensuring designability as a game board, it is preferable to use a transparent thermoplastic resin such as an acrylic resin or a polycarbonate resin, and among these, it is preferable to use an acrylic resin. Polycarbonate resin is usually coated with a surface coating to prevent scratches on the surface, and this surface coating protects organic solvents to some extent, whereas acrylic resin does not require a surface coating. Therefore, the occurrence of cracks can be effectively suppressed by the action of the present invention.

  You may make it hold | maintain the game nail of this invention with a different holding force according to the depth from the surface of a game board. For example, a predetermined depth from the surface of the game board can be held with a low holding force or no holding state, and a portion deeper than that can be held with a high holding force. In this specification, a region that is held with a low holding force or is in a non-holding state is referred to as a low holding region, and a region that is held with a high holding force is referred to as a high holding region. The high holding region is located in all or part of a range deeper than the low holding region. The low holding force means a holding force that allows local displacement or bending of the game nail by the collision of the game ball. The high holding force only needs to be relatively higher than the holding force in the low holding region, and may be any holding force that can suppress the displacement or bending described above than in the low holding region. The holding force does not necessarily have to be constant in the low holding region and the high holding region, and the holding force does not have to change discontinuously between the two regions, and a mode in which the holding force changes continuously may be adopted. good.

  Since the game nail is preferably held firmly so that the position and posture thereof do not change due to the collision of the game ball, the holding force of the high holding region may be sufficient to hold the game nail in this way. Moreover, as long as the holding force is higher than that of the low holding region, the game nail may not necessarily be firmly held. In this case, an area for holding the game nail with a firm holding force may be provided in a deeper area than the high holding area.

  By holding in this way, it is possible to improve the fatigue strength when a game ball collides with a game nail driven into a resin game board, that is, the fatigue strength against impact bending caused by the collision of the game ball. Has been confirmed. Although the cause of the improvement in fatigue strength in the present invention has not been completely elucidated, by providing the above-described low retention region, the following various effects are combined to reduce the bending moment and shear force in the impact bending. It is considered that the effect of mitigating is obtained, and as a result, the fatigue strength is improved.

  First, the influence of the behavior of elastic waves on the shear stress and bending moment caused by impact bending can be considered. As a comparative example, consider a case where the entire portion into which the game nail is driven is firmly held. At this time, when the elastic wave generated by impact bending reaches the base of the game nail (part of the surface of the game board), the game nail immediately receives a reaction from the game board. In addition, since the game nail is firmly held inside the game board, the base functions as a fixed end, and the elastic wave is reflected immediately. As a result, the elastic wave is repeatedly reflected between the root and the free end of the game nail. Such behavior causes the game nail to vibrate repeatedly, reducing the fatigue strength.

  Next, consider a case where a low holding area is provided near the surface of the game board. In this case, even if the elastic wave generated by impact bending reaches the base of the game nail, the game nail does not receive a large reaction from the game board. For example, in the case where there is a gap between the game nail and the game board, the reaction is not received until the game nail is bent and deformed so as to contact the game board. Even when there is no gap, the holding power of the game nail is weak, so when viewed microscopically at the base part, the bending deformation of the game nail is allowed, that is, it behaves like a gently constrained free end, The reaction acting on the game nail is considered to show a behavior that rises more slowly than the fixed end. During this time, the elastic wave passes through the root and travels through the low holding region, and this elastic wave is reflected at the boundary with the high holding region. A part of the elastic wave is reflected by a reaction from the game board at the base. As a result, the elastic wave caused by the impact bending is dispersed into the one reflected at the boundary with the high holding region and the one reflected at the base portion, and is reflected again between the free ends of the game nails. It is considered that the elastic waves dispersed in this way interfere with each other and suppress the vibration of the game nail. Strictly speaking, it is impossible to deny the possibility that the amplitude of the game nail will increase due to the interference between elastic waves, but this phenomenon appears in the high-dimensional vibration mode, which is the lowest dimension that most affects fatigue strength. The vibration mode is considered to be suppressed.

  Second, since the holding force of the game nail is low in the low holding region, it is considered that the support force for the base portion of the game nail is relatively low. Therefore, the reaction from the game board to the collision of the game ball is also reduced, and the shear stress itself acting on the base of the game nail can be reduced. This is the same principle that when a shock is applied to a member on a soft material, a large impact force does not act on the member.

  Third, it is considered that the game nail has a certain degree of deflection in the low holding area. Therefore, when the impact bending occurs, the impact energy can be absorbed by this deflection. Further, since the game nail has a space to bend in the low holding area, an effect of dispersing the bending moment in the low holding area is generated, and the stress applied to the base of the game nail can be relieved.

  Fourth, in the low holding area, the compressive stress acting on the game nail in the radial direction from the game board is low. Some of these compressive stresses act in the direction of increasing the shear stress accompanying bending depending on the direction. That is, if the game nail is held with a high holding force, an effect of partially increasing the shear stress acting on the game nail is produced, and there is a possibility that the fatigue strength is reduced. In the present invention, by providing the low holding region, this compressive stress can be reduced. Therefore, it is considered that the maximum value of this shear stress can be suppressed and the fatigue strength can be improved. It is considered that the influences of the first to fourth actions described above change depending on the pilot board hole and the size and shape of the game nail. The improvement in fatigue strength is not obtained by any one of these effects, but is considered to be obtained by combining a plurality of effects.

  The game nails are not only fatigued, but are firmly held without being disengaged from the game board or changing position or posture even when an impact load is applied (hereinafter referred to as the strength to hold firmly. "Retainability") is desired. In the present invention, the depth of the low holding region may be arbitrarily set in consideration of both fatigue strength and holding properties. As an example, by making the depth of the low holding region equal to the depth of the high holding region, a balance between both fatigue strength and holding property can be realized relatively easily. In this case, the holding force in the high holding region is preferably set to a value sufficient to hold the game nail firmly.

  The game nail can be held by being driven so as to be inserted into a prepared hole formed in advance in the game board. In this case, as a method for realizing the high holding area, for example, a method in which the ratio of the diameter of the game nail to the diameter of the pilot hole in the high holding area is made larger than the ratio in the low holding area. For game nails having a constant diameter in the low holding region and the high holding region, the pilot hole diameter may be small in the high holding region and greatly changed in the low holding region. On the contrary, the pilot hole diameter may be constant, and the diameter of the game nail may be large in the high holding area and small in the low holding area. Both the pilot hole diameter and the game nail diameter may be changed in the low holding area and the high holding area.

  Moreover, various settings can be made for the diameter of the pilot hole in the low holding region. For example, from the viewpoint of sufficiently reducing the holding force of the game nail, the diameter of the prepared hole in the low holding region is preferably equal to or larger than the diameter of the game nail, and more preferably larger than the diameter of the game nail. When the pilot hole is made larger than the diameter of the game nail, the degree of freedom of deflection of the game nail is increased, so that it is expected that the impact energy absorption effect by the deflection is enhanced, and the fatigue strength can be further improved.

  The present invention does not have to have all the features described above, and may be applied by omitting or combining some of them as appropriate. As a specific aspect in which the above-described features are combined, the present invention can adopt the following configuration. First, the body of the game nail has a constant body diameter, and a knurled portion having a diameter larger than the body diameter is formed in a predetermined range on the driving side. The knurled portion has a shape having various characteristics described above for the game nail, such as a spiral ridge having a chamfered top. A pilot hole having a diameter larger than the body diameter and smaller than the large diameter is formed on the game board. The pilot hole diameter can be arbitrarily set, but it is preferable that the difference between the pilot hole diameter and the body diameter is 1/5 or less of the difference between the large diameter and the pilot hole diameter. Then, the game nail is driven in such a state that the boundary between the trunk and the knurled portion is buried in the pilot hole.

  By doing so, a portion deeper than the boundary between the trunk and the knurled portion becomes a high holding region, and a shallow portion becomes a low holding region. As a result, the fatigue strength can be improved while firmly holding the game nail at the knurled portion. The depth at which the game nail is driven can be set arbitrarily, but as described above, it is preferable to drive the game nail so that the boundary between the trunk and the knurled portion comes at a position where the low holding area and the high holding area are equivalent. . In such a holding method, since the pilot hole diameter is larger than the trunk diameter, the organic solvent may permeate into the pilot hole when cleaning the surface. However, when the game nail of the present invention is used, the knurled portion Due to the shape characteristics, it is possible to suppress the stress and notches that occur in the game board during driving, and thus the generation of cracks can be suppressed.

Embodiments of the present invention will be described in the following order. In this embodiment, a configuration example as a pachinko machine is shown, but the gaming machine may be a smart ball.
A. Game machine configuration:
B. Game nail holding structure:
C. effect:
D. Variation:

A. Game machine configuration:
FIG. 1 is a front view of a game board 5 provided in a pachinko machine. A game area 37 is provided at the center of the game board. When a player operates a handle (not shown) to fire a game ball, the game ball is guided by a set of rails 76 and 77 and is driven into the game area 37 to flow down the game board 5.

  The game board 5 is provided with start winning ports 212 and 214, a general winning port 224, and a variable winning device 210. When winning is awarded here, a prize ball is paid out. In addition, when the winning winning openings 212 and 214 are won, a lottery is performed electronically. As a result of the lottery, the open / close member 274 located above opens and closes a predetermined number of times when a big hit is achieved. If a prize is awarded when the opening / closing member 274 is open, a prize ball can be obtained.

  A game nail 230 is driven into the game area as an obstacle to the game ball flowing down. Since the game ball flows down to the game nail 230 while changing the collision trajectory, the player can enjoy the movement of the game ball while expecting the game ball to win. The game nail 230 needs to be firmly fixed so that it can withstand the impact force caused by the collision of the game ball flowing down in this manner and can maintain the preliminarily placed posture and position. Further, from the viewpoint of the durability of the gaming machine, it is preferable to have a sufficient fatigue strength so that it does not easily break even when subjected to such an impact force.

  In the present embodiment, a transparent resin flat plate into which the game nail 230 is driven out of members constituting the game board 5 is referred to as a holding plate. The holding plate can be formed by extrusion molding of a transparent resin such as polycarbonate resin, polyarylate resin, or acrylic resin. It is preferable to use an acrylic resin as a material that can prevent scratches on the surface without performing surface coating. The thickness W2 of the holding plate can be arbitrarily set as long as a game nail or the like to be placed can be sufficiently held. In this embodiment, the thickness W2 is 8 to 10 mm. In addition to the game nail 230, a start winning port 212, 214, a general winning port 224, a variable winning device 210, and the like are attached to the holding plate. By using the transparent resin as the holding plate, the player can visually recognize an effective performance using the entire surface of the game board 5 by the light emitting decoration body 238 of the decoration unit 240 arranged on the rear side. Further, such a holding plate can make the player feel the feeling that the game nail 230 is floating in the air and make the entire game board feel the depth.

  In the center of the game board 5, a liquid crystal panel as an effect display device 202 is arranged. The effect display device 202 may use an organic EL, an LED, a plasma display, or the like in addition to the liquid crystal panel. It is possible to enhance the interest of the game by displaying various effects such as displaying a lottery result indicating whether or not the game is a big hit during the game.

B. Game nail holding structure:
FIG. 2 is an explanatory view showing the shape of the game nail 10. A game nail 230 (see FIG. 1) is configured by being driven into the game board 5. Hereinafter, a single state is referred to as a game nail 10 in order to distinguish from a state in which the game board 5 is driven according to the gauge arrangement.

  2A is a perspective view, FIG. 2B is a side view, and FIG. 2C is a cross-sectional view taken along line AA. The game nail 10 includes a cylindrical body portion 13 having a constant diameter, a head portion 14 formed at one end thereof, a knurled portion 12 formed at the other end, and a tip portion 11. The tip 11 is hemispherical. By doing so, the relative positional relationship between the holding plate and the nailing machine is shifted when nailing, and even if the holding plate is slightly deviated from the center of the pilot hole, the game nail 10 is inserted into the game nail 10 from the wall surface of the pilot hole. The force acts so that 11 naturally fits in the center of the pilot hole. If the tip 11 is cut off flatly or has a shape such as a tapered shape where a flat surface appears at the tip, the force that guides the game nail to the center of the pilot hole is difficult to act from the panel. May crack or overload the nailer. In this embodiment, there is an advantage that these adverse effects can be avoided by making the tip hemispherical as described above. At the same time, the game nail 10 can be restrained from being pushed into the pilot hole in an unreasonable posture, and thus there is an effect of reducing the residual stress of the holding plate.

  The knurled portion 12 can be formed by rolling. The maximum diameter of the knurled portion 12 is slightly larger than the outer diameter of the trunk portion 13 (hereinafter referred to as the trunk diameter). The minimum diameter is slightly smaller than the trunk diameter, but is more preferably equal to or larger than the trunk diameter.

  The knurled portion 12 is formed with a spiral ridge 15. As shown in FIG. 2C, four ridges 15 are provided around the axis at intervals of 90 degrees. The fact that a plurality of ridges 15 are provided in this way is called multi-row. The top portion of the ridge portion 15 is not an acute angle, but a rounded chamfer with a convex curved surface. Instead of R chamfering, planar chamfering may be performed. The valley portions 16 between the ridge portions 15 are formed in a concave curved surface shape.

  FIG. 3 is an explanatory diagram showing the relationship between the dimensions of the game nail 10 and the holding plate 242. FIG. 3A shows a cross-sectional view of the holding plate 242 into which the game nail 10 is driven. The game nail 10 is driven in a state of protruding from the surface of the holding plate 242 by a protruding amount L so as to be inserted into the prepared hole 242h drilled in the holding plate 242. The protruding amount L is 18.0 mm (16.8 mm excluding the head 14). The game nail 10 has such a length that it does not protrude from the back surface of the holding plate 242 having a thickness W2 when the game nail 10 is driven with the protrusion amount L secured. That is, the total length Ln of the game nail 10 is substantially equal to or slightly shorter than “L + W2”.

  The length h3 from the surface of the holding plate 242 in the driven state to the tip of the game nail 10 is hereinafter referred to as a driving depth. The length h2 of the knurled portion 12 is a part of the driving depth h3 (almost half in this embodiment). If the length of the driving depth h3 corresponding to the body portion 13 is h1, h1 and h2 are equal. However, the ratio of h1 and h2 can be set arbitrarily.

  FIG. 3B shows an enlarged view of a portion where the game nail 10 is driven into the holding plate 242. An outer diameter (hereinafter, referred to as “knurl portion outer diameter”) d2 of the knurled portion 12 is larger than a diameter (hereinafter, referred to as “body diameter”) d1 of the trunk portion 13. The diameter Dh of the pilot hole 242h (hereinafter referred to as “the pilot hole diameter”) Dh can be an arbitrary value in a range of “d1 ≦ Dh <d2”. Since the holding force and fatigue strength of the game nail 10 are affected by the diameter of the pilot hole, it may be determined by experiments or the like within the above-mentioned range in consideration of both. From the viewpoint of ensuring fatigue strength, the pilot hole diameter Dh is preferably not smaller than the trunk diameter d1.

  When the game nail 10 is viewed from the side, as shown in FIG. 3B, the inclination angle θ of the ridge 15 with respect to the cross section orthogonal to the axis of the game nail is approximately 60 degrees. The ridge portion 15 makes a substantially half turn around the axis while reaching the other end of the knurled portion 12. That is, the twist angle of the ridge portion 15 is approximately 180 degrees. By adopting such a shape, the rotation of the game nail 10 around the axis at the time of driving can be suppressed to about 180 degrees, and the stress and notch generated in the holding plate 242 can be suppressed. However, dimensions such as an inclination angle of 60 degrees and a twist angle of 180 degrees are not essential, and may be different values. However, in order to suppress the occurrence of stress and notches, it is generally preferable that the tilt angle is large and the twist angle is small.

C. effect:
C1. Suppression effect of crack generation:
When the game nail 10 of the example was used, it was confirmed that the crack as shown in FIG. 7 did not occur even when the surface of the holding plate 242 was wiped with an organic solvent such as alcohol. The reason why such an effect can be obtained is not completely elucidated, but is presumed to be due to the following action.

  FIG. 4 is an explanatory diagram showing the effect of suppressing the occurrence of cracks. FIG. 4A shows a cross-sectional view of the holding plate 242 when the game nail 10 of the embodiment is used. For convenience of explanation, FIG. 4B shows a cross-sectional view of the holding plate 242A when a game nail 10A as a comparative example is used. The game nail 10A also has a knurled portion 12A at the tip, and of the driving depth, the dimension h2A of the knurled portion 12A and the length h1A of the portion corresponding to the body portion 13 are the game nail of the embodiment. Combined with 10. However, in the game nail 10A of the comparative example, the crest portion 15A of the knurled portion 12A is a single line, and the top portion has an acute angle. The inclination angle θA of the ridge 15A is a shallow angle of about 20 degrees. The twist angle is 720 degrees, that is, the ridge portion 15A is formed to make two rounds around the axis. The valley portion 16A other than the ridge portion 15A has a columnar shape with a diameter d2A slightly smaller than the diameter d1A of the body portion 13A.

  When the game nail 10 of the embodiment is driven as shown in FIG. 4A, the top portion of the crest portion 15 is chamfered, so that when the biting into the holding plate 242, a sharp notch is formed in the pilot hole 242h. It is considered that the formation of can be suppressed. Moreover, as a result of suppressing the formation of such a notch, stress concentration generated at the tip can also be relaxed. On the other hand, when the top portion 15A has an acute angle like the game nail 10A of the comparative example, a sharp notch is formed in the pilot hole 242hA when driven into the holding plate 242A as shown in FIG. 4B. Many will be formed. Solvent cracks are said to occur when a resin in which stress remains remains in contact with an organic solvent. When the game nail 10 of the embodiment is used, as shown in FIG. 4A, even if an organic solvent such as alcohol penetrates the pilot hole 242h as shown by the arrow S1, the stress of the pilot hole 242h is suppressed. Therefore, cracks are unlikely to occur. On the other hand, in the game nail 10A of the comparative example, when the organic solvent penetrates into the pilot hole 242hA as indicated by the arrow S2, cracks are likely to occur due to the stress or notch generated in the pilot hole 242hA.

  Further, in the knurled portion 12 of the embodiment, since the twist angle of the ridge portion 15 is 180 degrees or less, it is possible to suppress excessive rotation of the game nail 10 and suppress stress generated in the holding plate 242 when driven. be able to. When the helix angle of the ridge portion 15A is large as in the game nail 10A of the comparative example, the game nail 10A rotates forcibly when driven, and high stress is likely to be generated on the holding plate 242A. Moreover, in the game nail 10, since the ridge part 15 is made into a multi-strip | row, there also exists an effect which can suppress the stress at the time of driving. With these actions, the game nail 10 can suppress stress more than the game nail 10A of the comparative example, and can suppress the occurrence of cracks.

  Further, as described above, the game nail 10 of the embodiment has the tip 11 formed in a hemispherical shape. By guiding the game nail 10 to the central portion of the pilot hole 242h by this semi-vacuum shape, it is possible to avoid the game nail 10 being driven into the holding plate 242 in an unreasonable posture, and to suppress the stress generated in the holding plate. it can.

  Further, when the valley portion 16A is formed in a columnar shape like the game nail 10A of the comparative example, an angle is generated at the boundary between the hill portion and the valley portion. Cheap. On the other hand, in the game nail 10, since the valley portion 16 has a concave curved surface, such an unreasonable deformation can be suppressed and the stress generated in the holding plate 242 can be suppressed. Further, by making the valley portion 16 a concave curved surface, the degree of adhesion between the game board and the surface of the game nail can be increased, and even if the organic solvent permeates as shown by the arrow S1, the portion where the knurled portion 12 is driven Then, it can suppress that an organic solvent touches the pilot hole 242h. The contact between the organic solvent and the pilot hole 242h can also be suppressed by setting the minimum diameter of the knurled portion 12 of the game nail 10 to be equal to or larger than the trunk diameter.

  When the game nail 10 is used, it is considered that the occurrence of cracks can be suppressed by at least a part of the above-described actions. However, which is dominant depends on the dimensions of the game nail 10 and the pilot hole 242h, the speed at the time of driving, and the like.

C2. Fatigue strength improvement effect:
According to the pachinko machine of the embodiment, the fatigue strength can be improved by setting the shape and pilot hole diameter of the game nail 10 and the driving depth of the game nail 10 to the state shown in FIG. That is, 1) a knurled portion 12 having a diameter d2 larger than the body diameter d1 is provided at the tip of the game nail 10; 2) the pilot hole diameter Dh is set to “d1 ≦ Dh <d2”; 3) the knurled portion 12 The nail 10 is driven so that the boundary portion between the body portion 13 and the body portion 13 is buried in the holding plate 242. Preferably, the depth h2 of the knurled portion 12 and the depth h1 of the body portion 13 are equal to each other in the driving depth h3. Fatigue strength is improved by driving the game nail 10 in a state of being driven.

  FIG. 5 is an explanatory diagram showing the fatigue strength confirmation test results. The outline of the test is shown in FIG. As shown in the drawing, a game nail N as a test piece is driven into the game board 5, and a game ball P is driven through the rails 76 and 77 with the maximum firing strength to apply an impact force to the game nail N. This operation was repeated, and the number of repetitions until the game nail N broke due to fatigue was measured as the fatigue life.

FIG. 5B shows the test results when the shape and the fixed state of the game nail N are changed. The horizontal axis shows the relationship between the pilot hole diameter and the body diameter, and the vertical axis shows the fatigue life. ●, x and ■ are test results of game nails with different shapes. Each shape is as follows.
●… Knurled outer diameter d2;
X ... Knurled portion outer diameter d21 = d2-0.02 mm;
■ Knurled outer diameter d22 = d2-0.05mm

  As can be seen from the result of the outer diameter d2 of the knurled portion, the fatigue life is extremely short in the range where the pilot hole diameter is smaller than the trunk diameter, but the fatigue strength can be improved by making the pilot hole diameter equal to or larger than the trunk diameter. I understand. It can also be seen that the fatigue life increases as the pilot hole diameter increases. However, since the pilot hole diameter needs to be drilled within a range where the game nail can be held, the upper limit value is limited by the outer diameter of the knurled portion.

  It can be seen that the above-described effects can be obtained in the same manner with other game nails (× and ■ in the figure) having different knurled outer diameters. It can also be seen that even if the ratio of the body diameter and the pilot hole diameter is the same, the fatigue life is affected by the outer diameter of the knurled portion. However, there is no monotonous correlation between the knurled outer diameter and the fatigue life. That is, compared with the outer diameter d2, the fatigue strength decreases at d21 having a smaller outer diameter of 0.02 mm, whereas the fatigue strength increases at d22 smaller by 0.05 mm. However, if the result shown in FIG. 5 is evaluated only from the fatigue strength, d22 having the thinnest outer diameter is optimal. However, the game nail needs to satisfy not only the demand for fatigue strength but also the demand for holding force at the same time. This is because it is necessary to prevent the position of the game nail from changing due to the collision of the game ball or tilting the game nail during the game. This holding force is evaluated by the pulling force when pulling out the game nail that has been driven into the pilot hole. Although illustration of the experimental results is omitted, as is easily estimated, the holding force is smaller as the outer diameter is thinner. In this example, the outer diameter d22 is excluded from the candidates because it is evaluated that the holding force is insufficient, and the outer diameter d21 is excluded from the candidates because the fatigue strength is relatively low, and the optimum considering the balance between the fatigue strength and the holding force. As a result, the outer diameter d2 was selected.

  When a game nail is driven into a game board made of transparent resin, there may be a phenomenon that whitening becomes cloudy only in a portion where the game nail is driven into the transparent game board due to friction at the time of driving. It has been experimentally confirmed that whitening becomes more significant as the ratio of the outer diameter of the game nail to the lower hole diameter increases. The diameter of the game nail may be determined in consideration of the degree of whitening in addition to the above-described fatigue strength and holding force.

  FIG. 6 is an explanatory diagram showing the reason why the fatigue strength is improved. The reason is not completely elucidated, but it is thought that the following various effects are combined.

  First, the influence of the behavior of elastic waves on the shear stress and bending moment caused by impact bending can be considered. FIG. 6A shows the behavior when the entire insertion portion of the game nail 10 is firmly fixed as a comparative example. When the game ball P collides, a shear stress and a bending moment are generated in the game nail 10 by the impact load F. In the figure, the behavior of elastic waves based on shear stress is schematically shown. This elastic wave propagates in the direction of the arrow W1 in the figure while causing local bending in the game nail 10. When the elastic wave reaches the base of the game nail 10 (part of the surface of the game board), the game nail 10 immediately receives a reaction F1 from the game board. Since the game nail 10 is firmly held by the holding plate 242, the base functions as a fixed end, and the elastic wave is immediately reflected as indicated by an arrow w 2. As a result, the elastic wave is repeatedly reflected between the root and the head of the game nail. This behavior of the elastic wave causes the game nail to vibrate repeatedly, reducing the fatigue strength.

  FIG. 6B shows the behavior when the pilot hole diameter is larger than the trunk diameter. In this state, of the portion driven into the holding plate 242, the body portion 13 receives almost no holding force from the pilot hole 242 h in the portion of the depth h 1 from the surface to the knurled portion 12. . In this sense, the area up to the depth h1 is called a low holding area, and the portion h2 where the knurled portion 12 is driven is called a high holding area. When the low holding area is provided in this way, the elastic wave generated by the impact bending propagates as indicated by the arrow w1, and at the moment when the game nail 10 reaches the base of the game nail 10, the game nail 10 is greatly separated from the holding plate 242. There is no reaction. The reaction is received after the game nail 10 is deformed as indicated by a two-dot chain line in the figure. Until such deformation, the elastic wave passes through the root and travels through the low retention region as indicated by arrow w10. This elastic wave is reflected at the boundary between the knurled portion 12 and the body portion 13.

  On the other hand, when the game nail 10 is bent as indicated by a two-dot chain line, a reaction F2 is applied from the holding plate 242 to the game nail 10, so that a part of the elastic wave is reflected at the base as indicated by an arrow w21. As a result, the elastic wave due to the impact bending is dispersed into a wave corresponding to the arrow w10 that travels through the low holding region and is reflected at the boundary with the high holding region, and a wave indicated by the arrow w21 that is reflected at the base portion. Reflected again with 10 heads 14. The elastic waves dispersed in this way interfere with each other and suppress the vibration of the game nail. As a result, it is considered that there is an effect of improving the fatigue life.

  Second, since the holding force of the game nail 10 is low in the low holding region, it is considered that the support force for the base portion of the game nail 10 is relatively low. Accordingly, the reaction F2 from the holding plate 242 against the collision of the game ball P is also reduced, and the shear stress itself acting on the base portion of the game nail 10 can be relaxed. This is the same principle that when a shock is applied to a member on a soft material, a large impact force does not act on the member.

  Thirdly, it is considered that the game nail 10 has a certain degree of deflection as shown by a two-dot chain line in the figure in the low holding region. Therefore, when the impact bending occurs, the impact energy can be absorbed by this deflection. Further, since the game nail has a space to bend in the low holding area, an effect of dispersing the bending moment in the low holding area is generated, and the stress applied to the base of the game nail can be relieved.

  Fourth, in the low holding area, the compressive stress acting on the game nail in the radial direction from the game board is low. As shown in FIG. 6A, when the entire insertion portion of the game nail 10 is firmly held, a compressive stress Fp acts in the radial direction of the game nail 10 from the holding plate 242. Some Fp acts in a direction to increase the shear stress F1 accompanying bending depending on the direction. That is, when the game nail 10 is firmly held, an effect of partially increasing the shearing stress F1 acting on the game nail 10 is produced, and the fatigue strength may be reduced. In the present invention, by providing a low holding region, this compressive stress can be prevented from acting or can be reduced, so that the maximum value of this shear stress can be suppressed and the fatigue strength can be improved. It is considered possible. In the present embodiment, it is considered that the influences of the first to fourth actions described above change depending on the size and shape of the pilot hole of the game board and the game nail. The improvement of fatigue strength is not obtained by any one of these effects, but is considered to be obtained by combining a plurality of effects, and the effect has been confirmed by the test shown in FIG.

  Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that various configurations can be adopted without departing from the spirit of the present invention. In the embodiment, an application example to a pachinko machine has been shown. However, the present invention can be applied to a general structure for holding a game nail that receives a collision of a game ball such as a smart ball. The present invention can be applied not only to acrylic resin but also to various thermoplastic resin game boards.

It is a front view of the game board 5 with which the pachinko machine was equipped. FIG. 3 is an explanatory diagram showing the shape of a game nail 10. 4 is an explanatory diagram showing a relationship between the dimensions of the game nail 10 and a holding plate 242. FIG. It is explanatory drawing shown about the suppression effect of crack generation. It is explanatory drawing which shows the confirmation test result of fatigue strength. It is explanatory drawing which shows the reason which fatigue strength improves. It is the photograph of the crack which arose at the time of washing | cleaning.

Explanation of symbols

5 ... Game board 10, 10A ... Game nail 11 ... Tip part 12, 12A ... Knurled part 13, 13A ... Body part 14 ... Head 15, 15A ... Ling part 16, 16A ... Valley part 37 ... Game area 76, 77 ... Rail 202 ... Production display device 210 ... Variable winning device 212, 214 ... Start prize opening 224 ... General prize opening 230 ... Game nail 238 ... Luminous decoration 240 ... Decoration unit 242, 242A ... Holding plate 242h, 242hA ... Pilot hole 274 ... Opening / closing member

Claims (7)

In a gaming machine for winning a game ball in a predetermined winning opening, a game nail that is driven into a resin game board provided with the winning opening as an obstacle flowing down the gaming ball,
A cylindrical body portion having a predetermined body diameter;
A head portion formed in a plate shape having a diameter larger than the body diameter at a time of the body portion;
A knurled portion formed at the other end of the body portion and driven into the game board;
A game nail in which a spiral ridge is formed on the outer periphery of the knurled portion, and the top of the ridge is chamfered to an obtuse angle or a curved surface. The game nail according to claim 1,
A game nail in which the crest is formed such that a twist angle from once to the other end of the knurled portion is 180 degrees or less. The game nail according to claim 1 or 2,
A plurality of the nails are formed at predetermined intervals along the outer periphery of the knurled portion. The game nail according to claim 3,
The knurled portion is a game nail in which a valley portion between the ridge portions is a concave curved surface. The game nail according to any one of claims 1 to 4,
A game nail in which the diameter of the knurled portion is equal to or larger than the body diameter. A gaming machine for winning a game ball in a predetermined winning opening,
A resin game board provided with the winning opening;
A gaming machine comprising the game nail according to claim 1, which is driven into the game board as an obstacle flowing down the game ball. A gaming machine according to claim 6,
The gaming machine is a gaming machine made of acrylic resin.