JP5016068B2 - Obstacle nail for a ball game machine, a ball ball machine, a method for manufacturing an obstacle nail for a ball game machine, and a mold for forming an obstacle nail for a ball game machine - Google Patents

Description

  The present invention relates to an obstacle nail for a ball game machine, a ball ball machine, a method for manufacturing an obstacle nail for a ball game machine, and a mold for molding an obstacle nail for a ball game machine.

  A ball game machine such as a pachinko machine has a structure in which obstacle nails are driven into a game board according to a predetermined arrangement and the obstacle nails are held (fixed). After the obstacle nail is held on the game board, it is firmly held against the game board so that it does not rotate or fall out of the game board due to the collision of the game ball or the force applied for adjustment. It is necessary to

  The proposal about the technique relevant to a ball game machine is made conventionally (for example, refer patent documents 1-patent documents 3). In Patent Document 1, a material shaft having an enlarged head at one end of a straight shaft portion and a shank portion having a smaller diameter than the straight shaft portion at the other end side is twisted into the shank portion of the material shaft by plastic deformation. A pachinko machine nail is formed in which the outer diameter of the ridge between adjacent twisted grooves is the same as that of the shaft and a pointed portion is provided at the tip, and the pachinko machine nail is used as a holder. It is disclosed that the tip side including a part of the straight shaft portion of the pachinko machine nail is driven into the guide hole of the pachinko panel. According to Patent Document 1, since the crest of the torsion groove is substantially the same as the diameter of the straight shaft portion, the straight shaft portion fills the panel portion shaved off by the straight shaft, It is said that no gap is formed between them, and the aesthetic appearance of the nailing surface of the panel can be maintained.

  In Patent Document 2, a game board of a pachinko machine is formed of a resin such as acrylic or polycarbonate, a pilot hole is made therein, a game nail is driven in, and a spiral portion having a diameter larger than the body diameter is provided at the tip of the game nail It is disclosed that the diameter of the pilot hole is not less than the body diameter and smaller than the outer diameter of the spiral portion. Further, Patent Document 2 discloses that the game nail is driven until the boundary between the spiral portion and the body portion is buried in the pilot hole, for example, until the depth from the surface to the boundary is equal to the depth of the spiral portion. Thus, it is said that it is possible to extend the fatigue life due to the impact force when the game ball collides with the game nail while securing the holding force of the game nail.

  In Patent Document 3, a reinforcing portion is formed on the shaft portion of a nail placed on a pachinko machine panel so as to protrude from the surface of the panel and penetrate into the thickness of the panel, and the outer diameter of the reinforcing portion is The projecting height from the panel surface of the reinforcing part is reinforced by the ball moving on the panel surface when the nail is driven into the panel at a set depth. It is disclosed that the appearance height and thickness cannot interfere with the part. According to Patent Document 3, since the reinforcing portion of the nail is formed at a portion intersecting with the panel surface where stress is concentrated when a bullet ball collides with the nail, durability against metal fatigue is increased. It is said that it is possible to extend the lifespan by suppressing breakage.

JP-A-7-275447 JP 2008-161638 A JP 2009-247816 A

  In a ball game machine, breakage (breakage) of the obstacle nail may be a problem, and it is important to improve the durability of the obstacle nail.

  Conventionally, wooden plywood has been used for the game board of the ball ball game machine. However, in recent years, attention has been focused on using synthetic resin products such as ABS in place of wooden plywood, which is a forest resource, from the viewpoint of protecting the global environment. In particular, by using a transparent resin product, it is possible to install a liquid crystal display, a decoration unit, and the like on the back side of the game board, thereby enhancing the effect of the effects during the game. However, the obstacle nail that is driven and held on the base of such a synthetic resin product has a problem that it is broken in a short period of time compared to the one that is driven and held on a conventional wooden plywood. There are several possible causes for this, but synthetic resin products have a higher hardness than wooden plywood, and when a game ball collides with an obstacle nail, stress concentration occurs near the surface of the game board at the axis of the obstacle nail. It is thought that it is caused.

  The present invention provides a highly durable obstacle nail for a ball game machine, a bullet ball machine having the highly durable obstacle nail, a highly durable obstacle nail manufacturing method, and a molding die. The purpose is to provide.

  One aspect of the present invention made in view of the above problems is an obstacle nail of a ball game machine having a head and a shaft portion, and the shaft portion includes a bullet ball collision portion integrated with the head, A front end portion held by the game board of the ball game machine, and an intermediate portion provided between the ball impact portion and the front end portion, the intermediate portion of the ball impact portion An obstacle nail having a diameter equal to or less than an outer diameter and higher in hardness than the bullet impact portion.

  According to this, the obstacle nail can be held on the game board smoothly, and the durability of the obstacle nail can be improved. And, not all of the range corresponding to the ball colliding part and the intermediate part is made hard, but by making the intermediate part harder than the ball colliding part, when the game ball collides with the obstacle nail The change in the repulsive force can be reduced, and the durability of the obstacle nail can be improved while maintaining the game performance of the ball game machine.

  In this obstruction nail, the hardness of at least the surface layer portion on the outer peripheral surface of the intermediate portion may be higher than that of the bullet impact portion. According to this, toughness in the intermediate part can be ensured.

  In this obstruction nail, the surface layer portion of the outer peripheral surface of the intermediate portion, which is harder than the bullet impact portion, may be formed by a work hardened layer by forging. According to this, toughness in the intermediate portion can be suitably secured.

  In this obstruction nail, the outer peripheral surface of the intermediate portion may be a concave arc shape in the axial direction of the shaft portion. According to this, generation | occurrence | production of the stress concentration in an intermediate part can be suppressed.

  In this obstacle nail, the intermediate portion may have a diameter that is equal to or smaller than the outer diameter of the tip portion. According to this, the obstacle nail can be smoothly held on the game board. Even if at least a part of the intermediate portion is inserted into the game board, reaction force from the game board based on this can be prevented from acting on the intermediate portion.

  Another aspect of the present invention is a ball game machine characterized by including any one of the above-described obstacle nails and a game board that holds the tip of the obstacle nail. According to this, it is possible to provide a highly durable bullet ball game machine with respect to breakage of the obstacle nail while maintaining the game performance of the ball ball game machine.

  In this bullet ball game machine, at least a part of the intermediate part may be inserted into the game board in a state where the tip part is held on the game board. According to this, the durability of the obstacle nail in a state of being held on the game board can be improved.

  In this ball game machine, the outer peripheral surface of the intermediate portion is in non-contact with the insertion surface of the game board facing the outer peripheral surface of the intermediate portion in a state where at least a part of the intermediate portion is inserted into the game board. It may be characterized by being. According to this, it is possible to prevent a reaction force from the game board based on the insertion of the intermediate part into the game board from acting on the intermediate part. The stress acting on the intermediate portion can be reduced.

  Still another aspect of the present invention includes a head, a bullet ball collision unit integrated with the head, a tip held by a game board of a ball game machine, and the ball collision unit and the tip. A method of manufacturing an obstruction nail for the ball game machine, comprising a shaft portion having an intermediate portion that is provided between and having a diameter equal to or less than an outer diameter of the ball ball collision portion and higher hardness than the ball ball collision portion. The material nail serving as the obstacle nail is forged while rotating in a certain direction to form the tip, and the material nail is forged while rotating in the certain direction And a step of forming the intermediate portion. According to this, an obstruction nail can be manufactured suitably.

  In this manufacturing method, the step of forming the tip portion and the step of forming the intermediate portion may be performed simultaneously. According to this, the manufacturing cycle of the obstacle nail can be shortened.

  Still another aspect of the present invention includes a head, a bullet ball collision unit integrated with the head, a tip held by a game board of a ball game machine, and the ball collision unit and the tip. A mold for forming an obstacle nail for the ball game machine having a shaft portion having an intermediate portion which is provided between and having a diameter equal to or less than an outer diameter of the ball ball collision portion and higher hardness than the ball ball collision portion. A molding comprising: a tip molding portion for molding the tip portion; and an intermediate molding portion for molding the intermediate portion arranged in parallel to the tip molding portion. It is a mold. According to this, the manufacturing cycle of the obstacle nail can be shortened, and the obstacle nail can be preferably manufactured.

  According to the present invention, it is possible to obtain a highly durable obstacle nail for a ball game machine. In addition, it is possible to obtain a bullet ball game machine having the highly durable obstacle nail, a highly durable method of manufacturing the obstacle nail, and a molding die.

It is a figure which shows an obstruction nail. It is sectional drawing which shows the state by which the obstacle nail was hold | maintained at the game board of the ball game machine. It is a figure which shows the outline of the manufacturing process of an obstruction nail. (A) is a figure which shows schematic structure of the shaping die of an obstruction nail, (b) is a figure which shows schematic structure of a pair of shaping die set in order to shape an obstruction nail. (A) And (b) is a figure which shows the outline of the hardness test method of an obstruction nail. (A) is sectional drawing which shows the outline of the failure test method of a failure nail, (b) is an expanded sectional view of the A section shown to Fig.6 (a).

  Embodiments reflecting the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the configurations described below, and various configurations can be employed in the same technical idea. For example, some of the configurations described below may be omitted or replaced with other configurations.

(Handling of nails and obstacle nails)
The obstacle nail 100 shown in FIG. 1 is held by a game board 200 as shown in FIG. 2, and constitutes a ball game machine together with the game board 200 and the like. As shown in FIG. 1, the obstacle nail 100 has a head portion 110 and a shaft portion 120, which are integrally formed. The obstacle nail 100 is made of tempered brass, for example.

  The shaft part 120 has a bullet ball collision part 122, a tip part 124, and an intermediate part 126. A head 110 is formed on one end side of the bullet ball collision unit 122, and the bullet ball collision unit 122 is integrated with the head 110. In the bullet ball game machine having the game board 200 on which the obstacle nail 100 is held, the game ball collides with the bullet ball collision unit 122. The game ball that has collided with the ball colliding unit 122 repels in a predetermined direction.

  A spiral concavo-convex ridge is formed on the distal end portion 124 by a method described later. That is, the front end portion 124 is formed in a screw shape. The distal end of the distal end portion 124, in other words, the end opposite to the intermediate portion 126 is formed in a hemispherical shape. The front end portion 124 is held on the game board 200 of the ball game machine.

  The intermediate part 126 is provided between the bullet ball collision part 122 and the tip part 124. The position where the intermediate portion 126 is provided is a predetermined position where the game ball does not collide with the intermediate portion 126 in a state where the obstacle nail 100 is held by the game board 200. The intermediate part 126 is formed to have a diameter equal to or smaller than the outer diameter of the bullet ball collision part 122. The outer peripheral surface of the intermediate portion 126 has a concave arc shape in the axial direction of the shaft portion 120. In other words, the outer peripheral surface of the intermediate portion 126 has a constricted shape. The intermediate portion 126 has a higher hardness than the bullet impact portion 122. More specifically, the hardness of the surface layer portion is higher than that of the bullet ball collision portion 122 on the outer peripheral surface of the intermediate portion 126.

  An interposition part 128 is provided between the tip part 124 and the intermediate part 126. Therefore, in detail, the shaft portion 120 is formed by integrating the bullet ball collision portion 122, the tip portion 124, the intermediate portion 126, and the interposition portion 128. Further, the intermediate portion 126 is formed by subjecting a part of the portion including the range to be the bullet impact portion 122 to a forging process such as rolling by a method described later. Therefore, the interposition part 128 is the same diameter as the bullet ball collision part 122 and has the same mechanical characteristics.

  The outer diameter φ1 (hereinafter also referred to as “the outer diameter φ1 of the intermediate portion 126”) of the smallest diameter portion (the narrowest portion) in the intermediate portion 126 is set to a diameter that is equal to or smaller than the outer diameter φ2 of the bullet impact portion 122. Is done. Further, the outer diameter φ1 of the intermediate portion 126 is set to a diameter equal to or smaller than the outer diameter φ3 of the distal end portion 124. Specifically, in the obstacle nail 100 shown in FIG. 1, the outer diameter φ1 of the intermediate portion 126 is set to be smaller than the outer diameter φ2 of the bullet ball collision portion 122 and the outer diameter φ3 of the tip portion 124. Note that the outer diameter φ3 of the distal end portion 124 is the outer diameter of the convex portion constituting the screw shape.

  The obstacle nail 100 is driven into a hole 210 formed in the game board 200 as shown in FIG. When driven, the obstacle nail 100 is inserted while rotating the hole 210 by the spiral ridges formed on the tip 124. By being driven, the front end portion 124 is held on the game board 200, specifically, the hole portion 210. The game board 200 is made of resin or the like. For example, it is formed of a transparent resin having a predetermined hardness. In a state where the obstacle nail 100 is driven into the hole portion 210 and the front end portion 124 is held by the game board 200, the intermediate portion 126 is inserted into the game board 200, specifically, inserted into the hole portion 210.

  In a state where the intermediate portion 126 is inserted into the game board 200, the outer peripheral surface of the intermediate portion 126 is not in contact with the insertion surface of the game board 200, that is, the inner surface of the hole portion 210, which is opposed to the outer peripheral surface of the intermediate portion 126. A predetermined gap s is formed between the two. Note that the outer diameter φ3 of the distal end portion 124 and the outer diameter φ1 of the intermediate portion 126 can be the same diameter, and in this case, a predetermined gap is not formed between them. In the obstacle nail 100, since the outer diameter φ1 of the intermediate portion 126 is set to be smaller or the same diameter as the outer diameter φ3 of the tip portion 124, the intermediate portion 126 is inserted into the game board 200. The pilot hole diameter of the hole portion 210 can be set without considering the outer diameter φ1 of the intermediate portion 126. Accordingly, it is possible to make it difficult for the user of the ball game machine to visually recognize the hole 210 in a state where the obstacle nail 100 is held by the game board 200.

(Manufacturing method and mold for obstruction nail)
The obstacle nail 100 is formed by rolling or the like with respect to a material nail 300 having a head 310 as shown on the left side of FIG. 3 and a straight shaft portion 320 in which the tip portion 124 and the intermediate portion 126 are not formed. Formed by processing. Specifically, the portion 326 of the shaft portion 320 is rolled by the molding die 400 to form the intermediate portion 126, and the portion 324 of the shaft portion 320 is rolled by the molding die 400 to form the tip portion 124. . The material nail 300 is formed, for example, by subjecting a tempered brass wire to a forging process.

  The molding die 400 has a tip molding part 410 and an intermediate molding part 420 as shown in FIG. The tip molding portion 410 and the intermediate molding portion 420 are attached and fixed to the base portion 430 of the molding die 400 so as to protrude from the reference surface G of the molding die 400. The tip forming portion 410 is a member for rolling and forming the tip portion 124. The tip forming portion 410 is composed of an uneven stripe forming portion 412 and a hemispherical forming portion 414. The concave / convex forming portion 412 is a member for forming a spiral concave / convex portion of the tip end portion 124. The concave / convex forming portion 412 is configured by arranging a plurality of convex portions inclined by an angle corresponding to the spiral of the concave / convex strip in a line with each other in a parallel positional relationship. The hemispherical molding part 414 is a member for molding the hemispherical shape at the tip of the tip part 124.

  The intermediate forming part 420 is a member for rolling and forming the concave arcuate intermediate part 126 in the axial direction of the shaft part 120. The intermediate forming portion 420 is disposed along the concavo-convex forming portion 412 in parallel. The concave / convex forming part 412 and the hemispherical forming part 414 are arranged parallel to each other. Therefore, the intermediate molding part 420 is also arranged in parallel with the hemispherical molding part 414. Therefore, the tip forming part 410 and the intermediate forming part 420 are arranged in parallel to each other.

  When molding the obstacle nail 100, first, as shown in FIG. 4B, the molding surface on which the pair of molding dies 400 and 400 are provided with the tip molding part 410 and the intermediate molding part 420 has a predetermined gap. It is set in a state that can be opposed to each other. Next, the material nail 300 is inserted into the gap from the input side with the head 310 on the upper side. Thereafter, the pair of molding dies 400, 400 move in relatively different horizontal directions. For example, one molding die 400 moves in the “mold moving direction” shown in FIG. As a result, the portion 324 of the inserted material nail 300 is pressed against both of the tip forming portions 410 facing each other, and the portion 326 of the material nail 300 is pressed against both of the intermediate forming portions 420 facing each other. However, while rotating in the direction of the arrow “1” shown in FIGS. 4A and 4B, it proceeds from the input side toward the discharge side and passes through the range where these are arranged. Then, the obstacle nail 100 in which the tip end portion 124 is rolled by the tip forming portion 410 and the intermediate portion 126 is rolled by the intermediate forming portion 420 is discharged from the discharge side.

  That is, if the pair of molding dies 400, 400 are used, the step of rolling and forming the tip portion 124 and the step of rolling and forming the intermediate portion 126 can be performed simultaneously.

  Note that the molding die 400 that is set to face the molding die 400 shown in FIG. 4A includes the concave and convex strip forming portion 412 and the hemispherical molding portion 414, as in the molding die 400 of FIG. It has a tip forming portion 410 and an intermediate forming portion 420. In each of the pair of molding dies 400, 400, the tip molding part 410 and the intermediate molding part 420 are arranged at positions corresponding to the obstacle nail 100 to be molded, and have shapes or the like corresponding thereto. For example, the concavo-convex forming portions 412 included in each of the pair of molding dies 400 and 400 are respectively arranged at opposing positions in a state where the molding surfaces of the molding dies 400 are set so as to face each other. Moreover, each uneven | corrugated strip shaping | molding part 412 has a shape corresponding to the shape of a spiral uneven | corrugated strip. That is, the plurality of convex portions constituting each of the concavo-convex shaped portions 412 are inclined in a direction corresponding to the spiral direction.

(Hardness test)
A hardness test for the obstacle nail 100 of the present embodiment manufactured as described above will be described. For comparison with the obstacle nail 100 this time, the intermediate portion 126 is not formed, that is, the portion corresponding to the shaft portion 120 is an obstacle nail (hereinafter referred to as “the nail” formed by the bullet impact portion 122 and the tip portion 124. A hardness test was also conducted for “comparative nail”.) This will also be described. In addition, about the structure other than the intermediate part 126, the obstacle nail 100 and the comparison nail have the same structure.

  The hardness test was a Vickers hardness test, and a micro hardness tester (HM-221) manufactured by Mitutoyo Corporation was used. The measurement load was 0.1 kgf (0.98 N). In the hardness test, as shown in FIGS. 5 (a) and 5 (b), the hardness of the surface at positions of 8.5 mm and 13.5 mm from the tips of the obstacle nail 100 and the comparative nail was measured. Further, as shown in FIG. 5B, the surface as shown in FIG. 5B is targeted for the cross section VV at the position of 8.5 mm as shown in FIG. 5A and the cross section ZZ at the position of 13.5 mm. The hardness at the position of 0.1 mm from the center, the shaft center, and the middle between the surface and the shaft center was measured. The number of samples at each position was 3, and the average hardness was determined.

  Here, with respect to the obstacle nail 100 of the present embodiment, which is the subject of the hardness test, the intermediate portion 126 is formed in a range of 7.5 mm to 9.5 mm from the tip of the obstacle nail 100, and 8.5 mm from the tip. Is the position where the diameter of the intermediate portion 126 is smallest (see the outer diameter φ1 in FIG. 1). Note that the position 13.5 mm from the tip is a position belonging to the bullet ball collision unit 122.

First, the results of the hardness test at a position of 8.5 mm from the tips of the obstacle nail 100 and the comparative nail will be described with reference to Tables 1 and 2. As shown in Table 1, the surface hardness of the obstacle nail 100 averaged 218.27 HV0.1. On the other hand, the hardness of the surface of the comparative nail showed 189.30HV0.1 on average.

  The hardness at a position of 0.1 mm from the surface of the obstacle nail 100 showed an average of 224.03HV0.1 as shown in Table 2. On the other hand, the surface hardness of the comparative nail showed 187.73 HV0.1 on average.

  The average hardness of the surface of the obstacle nail 100 is about 15.3% higher than that of the comparative nail. The average hardness at a position of 0.1 mm from the surface of the obstacle nail 100 is about 19.3% higher than that of the comparative nail. This is because the surface layer portion of the outer peripheral surface of the intermediate portion 126 of the obstacle nail 100 is formed by a work hardened layer plastically deformed by rolling.

As shown in Table 2, the average hardness between the surface of the obstacle nail 100 and the shaft center was 180.97HV0.1. On the other hand, the average hardness of the comparative nails was 194.03 HV0.1 on average. Moreover, the hardness of the shaft center of the obstacle nail 100 showed 184.97HV0.1 on average. On the other hand, the hardness of the shaft center of the comparative nail showed 195.17HV0.1 on average.

  In the obstacle nail 100, the average hardness of the surface of the intermediate portion 126 and the average hardness of 0.1 mm from the surface are higher than the average hardness of the shaft center and the average average hardness. Note that this is not possible with comparative nails.

Next, the results of the hardness test at a position of 13.5 mm from the tips of the obstacle nail 100 and the comparative nail will be described with reference to Tables 3 and 4. The surface hardness of the obstacle nail 100 was 187.70 HV0.1 on average as shown in Table 3. On the other hand, the hardness of the surface of the comparative nail showed 196.17HV0.1 on average.

  The hardness at a position of 0.1 mm from the surface of the obstacle nail 100 showed an average of 180.30HV0.1 as shown in Table 4. On the other hand, the hardness of the surface of the comparative nail showed 192.97 HV0.1 on average. At the position of 13.5 mm from the tip, the average hardness of the surface of the obstacle nail 100 and the average hardness of the position of 0.1 mm from the surface are compared as the result of the hardness test at the position of 8.5 mm from the tip. A state in which the hardness is higher than the average hardness of the nail surface and the average hardness at a position of 0.1 mm from the surface is not recognized.

As shown in Table 4, the average hardness between the surface of the obstacle nail 100 and the shaft center was 201.17HV0.1. On the other hand, the average hardness of the comparative nail was 189.53 HV0.1 on average. Moreover, the hardness of the shaft center of the obstacle nail 100 showed 193.73HV0.1 on average. On the other hand, the hardness of the shaft center of the comparative nail showed 182.70 HV0.1 on average.

  In the obstacle nail 100, at the position of 13.5 mm from the tip, the average hardness of the surface and the average hardness of 0.1 mm from the surface are intermediate between them, as the result of the hardness test at the position of 8.5 mm from the tip. A state where the hardness is higher than the average hardness and the average hardness of the shaft center is not recognized.

  Here, considering the result of the hardness test at the positions of 8.5 mm and 13.5 mm from the tip for the obstacle nail 100, the average hardness of the surface at the position of 8.5 mm from the tip is 13.5 mm. It is about 16.3% higher than the position of. The average hardness at a position 0.1 mm from the surface at a position 8.5 mm from the tip is about 24.3% higher than that at a position 13.5 mm. This is because the surface layer portion of the outer peripheral surface of the intermediate portion 126 of the obstacle nail 100 is formed by a work hardened layer plastically deformed by rolling. On the other hand, with respect to the intermediate hardness between the surface and the shaft center and the average hardness of the shaft center, such a change in hardness was observed at each position of 8.5 mm and 13.5 mm from the tip. Absent. This is because work hardening does not occur at the intermediate and axial positions even at a position of 8.5 mm from the tip.

(Destructive testing)
A destructive (breaking) test for the obstacle nail 100 of the present embodiment manufactured as described above will be described. This time, in order to compare with the obstacle nail 100, a destructive test was also performed on a comparative nail in which the intermediate portion 126 was not formed as in the hardness test and a cutting nail formed by cutting a shape corresponding to the intermediate portion 126. Therefore, this will also be described. The obstacle nail 100, the comparison nail, and the cutting nail each had a diameter of φ1.85 mm and a total length of 26.5 mm. In the obstacle nail 100, the concave arc shape in the axial direction forming the outer peripheral surface of the intermediate portion 126 is an arc having a radius of 10 mm. Further, the intermediate portion 126 has a length in the axial direction of 2 mm, and the position where the diameter of the intermediate portion 126 becomes the smallest (see the outer diameter φ1 in FIG. 1) is a position 8.5 mm from the tip of the tip portion 124. did. The shape of the portion corresponding to the intermediate portion 126 in the cutting nail was the same as that of the intermediate portion 126. The obstacle nail 100, the comparative nail and the cutting nail were formed of tempered brass.

  The obstacle nail 100 and the comparative nail have the same configuration except for the intermediate portion 126. Further, the obstacle nail 100 and the cutting nail are different in the formation method of the intermediate portion 126, but the configuration (dimensions) of each portion is the same.

  The destructive test was performed using a predetermined testing machine (a folding testing machine). Specifically, as shown in FIGS. 6A and 6B, the game board (see game board 200 in FIG. 2 is referred to as “game board 200” as in FIG. 2 for convenience of explanation). As shown in FIG. 6A, the impact nail 100, the comparison nail or the cutting nail is repeatedly impacted by the hammer portion H, and the failure nail 100, the comparison nail and the cutting nail are broken and broken ( The number of shots that were damaged) was counted. In addition, since the diameter of the game ball is φ11 mm, the hammer portion H is installed at a position away from the surface M of the game board 200 by 5.5 mm, which is a half of the diameter of the game ball φ11 mm, in the folding tester. Has been.

  Here, the folding tester has a rotation drive unit connected to the hammer unit H. In the destructive test, this was rotated at 300 rpm, and an impact of 300 times per minute was applied to the obstacle nail 100 or the like held on the game board 200. The impact application position by the hammer part H was set to be the same position as the position where the game ball collides in the ball game machine by installing the hammer part H at the above position.

  The game board 200 used for the destructive test was a resin board, in which a hole 210 having a pilot hole diameter of φ1.86 mm was formed, and the obstacle nail 100, a comparative nail or a cutting nail was driven and held. The details of the state of holding the obstacle nail 100, the comparison nail or the cutting nail on the game board 200 and the dimensions of each part are as shown in FIGS. 6 (a) and 6 (b). 6A and 6B depict the mode of the destructive test based on the obstacle nail 100. FIG.

  Here, with respect to the obstacle nail 100, between the position where the diameter of the intermediate portion 126 becomes the smallest (see the outer diameter φ 1 in FIG. 1) and the surface M of the game board 200 when held on the game board 200. The dimension N was changed in the range of 0 to 2 mm, and a destructive test was performed in each changed state. For example, when the dimension N is set to 0 mm, the position where the diameter of the intermediate portion 126 is the smallest and the surface M of the game board 200 coincide with each other. Further, when the dimension N is set to 1 mm, the one end T of the intermediate portion 126 and the surface M coincide with each other. Furthermore, when the dimension N is set to 2 mm, one end T of the intermediate portion 126 is inserted into the game board 200 by 1 mm from the surface M. The cutting nail was subjected to a destructive test in a state where the dimension N was set to 1 mm.

The results of the destructive test will be described. When the dimension N is 0 mm in the obstacle nail 100, the number of shots is 296,930 on average as shown in Table 5, and when the dimension N is 1 mm, the average is 479, It was 968 times. Similarly, when the dimension N was in the range of 1.5 to 1.75 mm, the number of shots was 455,546 on average, and when the dimension N was 2 mm, it was 514,738 on average. Regardless of the dimension N, the position where the obstacle nail 100 is broken is, for example, in the vicinity of the boundary between the intermediate portion 126 and the ball impacting portion 122, in the vicinity of the boundary between the intermediate portion 126 and the interposition portion 128, or with the distal end portion 124. It was near the boundary with the interposition part 128. On the other hand, the number of shots for the comparative nail was 157,722 on average as shown in Table 5, and was 148,782 for the cutting nail on average.

  In the obstacle nail 100, the number of shots until the nail is broken is larger than that of the comparative nail and the cutting nail regardless of the dimension N. For example, in this experiment, the number of shots increased by about 1.9 times compared to the comparative nail even in the case of the failure nail 100 in which the dimension N, which had a short life in the failure nail 100, was set to 0 mm. Moreover, it increased about 2 times with respect to the cutting nail. In comparison between the failure nail 100 having the longest life and the dimension N set to 2 mm and the comparison nail, the number of shots of the failure nail 100 increased by about 3.3 times. Further, in comparison with the cutting nail, the number of shots of the obstacle nail 100 increased by about 3.5 times. That is, the obstacle nail 100 has a larger number of shots until it breaks than the comparative nail and the cutting nail, and can improve durability.

(Modification)
The configuration of this embodiment can also be configured as follows.

  (1) In the above description, the obstacle nail 100 in which the outer peripheral surface of the intermediate portion 126 has a concave arc shape in the axial direction of the shaft portion 120 has been described as an example. In addition to such a configuration, the outer peripheral surface of the intermediate portion 126 may have a plurality of uneven shapes, for example. Even in this case, the intermediate portion 126 is formed to have a diameter equal to or smaller than the outer diameter of the bullet impact portion 122.

  (2) In the above description, for example, the obstacle nail 100 in which the outer diameter φ1 of the intermediate portion 126 is set smaller than the outer diameter φ2 of the bullet impact portion 122 as shown in FIG. In addition to such a configuration, the obstacle nail 100 may be configured such that the outer diameter φ1 of the intermediate portion 126 and the outer diameter φ2 of the bullet impact portion 122 are the same. In this case, the material nail 300 to be the obstacle nail 100 is different from the shape shown on the left side of FIG. 3, and the diameter of the portion 326 of the shaft portion 320 is the portion closer to the head 310 than the portion 326, in other words, It has a shape that has a larger diameter than the diameter of the part that becomes the bullet ball collision part 122.

  Alternatively, the obstacle nail 100 may have the same outer diameter φ1 of the intermediate portion 126 and the outer diameter φ3 of the distal end portion 124. Therefore, for example, the obstacle nail 100 may include a shaft portion 120 in which the outer diameter φ1 of the intermediate portion 126, the outer diameter φ2 of the bullet impact portion 122, and the outer diameter φ3 of the tip portion 124 are the same diameter. it can.

  (3) In the above description, the configuration in which the hardness of the surface layer portion of the outer peripheral surface of the intermediate portion 126 is higher than that of the bullet impact portion 122 by work hardening by plastic deformation by rolling has been described as an example. In addition to such a configuration, shot peening is performed on the outer peripheral surface of the intermediate portion 126 in a state where the work hardening layer is not formed as described above, and thereby, the surface layer portion of the outer peripheral surface of the intermediate portion 126 is plastically deformed. And a work-hardened layer can be formed. That is, a work hardening layer may be formed by applying a predetermined pressure to the portion 326 of the material nail 300 that becomes the outer peripheral surface of the intermediate portion 126 and performing a forging process and plastically deforming the portion 326.

  Further, the obstacle nail 100 is formed on the outer peripheral surface of the intermediate portion 126 in a state where the work hardened layer is not formed as described above, and a metal film or layer having a hardness higher than that of a base material such as brass is formed. It can also be set as a simple structure. Specifically, the hardness of the surface layer portion of the outer peripheral surface of the intermediate portion 126 may be higher than that of the bullet impact portion 122 by various modification methods such as plating, physical vapor deposition, chemical vapor deposition, or ion implantation.

  In any of the methods, the thickness of the outer peripheral surface layer portion of the intermediate portion 126 that is higher in hardness than the bullet ball collision portion 122 is suitably set under various conditions. For example, it may be set to the same thickness as described above. In addition, not only the surface layer portion but also the entire intermediate portion 126, that is, the shaft center (see “axis center” in FIG. 5B), the hardness may be higher than that of the bullet impact portion 122.

  (4) In the above, the tip molding part 410 and the intermediate molding part 420 are formed by forming the tip part 124 by forging using the molding die 400 arranged parallel to each other, and the intermediate part 126. The configuration in which the forging process and the molding process are performed simultaneously has been described as an example. In addition to such a configuration, a molding die having a tip molding portion 410 and a molding die having an intermediate molding portion 420 are prepared, and the tip portion 124 is forged and molded, and the middle portion 126 is The step of forging and forming may be a separate step. The configuration of the molding die can be simplified.

  In addition, it is good also as a shaping | molding metal mold | die which has arrange | positioned each without shifting the front-end | tip molding part 410 and the intermediate | middle shaping | molding part 420 along each other. In this case, after the material nail 300 is inserted, for example, the leading end portion 124 is formed by forging processing such as rolling, and the forging processing is performed on the material nail 300 in which the leading end portion 124 is formed. 126 is formed.

  (5) In the above, the game board 200 made of resin has been described as an example. It is good also as the game board 200 formed with the play wooden plywood other than resin.

  (6) In the above description, the obstacle nail 100 in which the interposition part 128 is provided between the distal end part 124 and the intermediate part 126 has been described as an example. Here, the interposition part 128 may be omitted, and the distal end part 124 and the intermediate part 126 may be continuous. In this case, the molding die 400 in which the tip molding portion 410 and the middle molding portion 420 are arranged in parallel to each other at a position corresponding to the arrangement of the tip portion 124 and the intermediate portion 126 is used. The

DESCRIPTION OF SYMBOLS 100 Obstacle nail 110 Head 120 Shaft part 122 Ball impact part 124 Tip part 126 Intermediate part 200 Game board

Claims (11)

An obstacle nail for a ball game machine having a head and a shaft,
The shaft portion is
A bullet impact unit integral with the head;
A tip held by the game board of the ball game machine;
Having an intermediate portion provided between the bullet impact portion and the tip portion;
The obstacle nail according to claim 1, wherein the intermediate portion has a diameter equal to or smaller than an outer diameter of the bullet ball collision portion and is harder than the bullet ball collision portion.   2. The obstacle nail according to claim 1, wherein at least an outer surface of the intermediate portion has a hardness of at least a surface layer portion higher than that of the bullet impact portion.   The obstacle nail according to claim 2, wherein a surface layer portion of the outer peripheral surface of the intermediate portion, which is harder than the bullet impact portion, is formed by a work hardened layer by forging.   The obstacle nail according to any one of claims 1 to 3, wherein the outer peripheral surface of the intermediate portion has a concave arc shape in the axial direction of the shaft portion.   The obstacle nail according to any one of claims 1 to 4, wherein the intermediate portion has a diameter equal to or smaller than an outer diameter of the tip portion. The obstacle nail according to any one of claims 1 to 5,
A bullet ball game machine comprising a game board holding a tip of the obstacle nail.   The ball game machine according to claim 6, wherein at least a part of the intermediate part is inserted into the game board in a state where the tip part is held on the game board.   The outer peripheral surface of the intermediate portion in a state where at least a part of the intermediate portion is inserted into the game board is not in contact with the insertion surface of the game board opposed to the outer peripheral surface of the intermediate portion. Item 8. A ball game machine according to Item 7. A head and a ball colliding part integral with the head, a tip held by a game board of a ball game machine, and the ball colliding part provided between the ball colliding part and the tip; A method of manufacturing an obstruction nail for the ball game machine, having a diameter equal to or less than the outer diameter of the portion and a shaft portion having an intermediate portion that is harder than the ball impact portion,
A step of forming the tip by forging the material nail to be the obstacle nail while rotating in a certain direction;
Forming the intermediate portion by forging the material nail while rotating it in the fixed direction.   The manufacturing method according to claim 9, wherein the step of forming the tip portion and the step of forming the intermediate portion are performed simultaneously. A head and a ball colliding part integral with the head, a tip held by a game board of a ball game machine, and the ball colliding part provided between the ball colliding part and the tip; A molding die for the obstacle nail of the ball game machine having a shaft portion having an intermediate portion having a diameter equal to or less than the outer diameter of the portion and having a hardness higher than that of the ball collision portion,
A tip molding part for molding the tip part;
A molding die having an intermediate molding part for molding the intermediate part, which is arranged in parallel with the tip molding part.

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