Balls for ball games

Abstract

A ball for a ball game includes a spherical skin portion at least a part of which is formed to be transparent in a manner that an inside space can be visually confirmed from the outside, a cylindrical holding portion provided to extend in the inside space in a manner that both poles of the skin portion are connected and having an enclosed space, and a held object held in the enclosed space in a manner that can be visually confirmed between the both poles. The cylindrical holding portion has a shape twisted in a spiral shape between the both poles. The cylindrical holding portion is twisted between the both poles by 135° or more and 270° or less.

Description

Technical Field

[0001] This invention relates to balls used in ball sports. Background Technology

[0002] Previously, it was known that balls used for competitive and practice sports such as soccer balls and volleyballs (see, for example, Patent Document 1). The ball described in Patent Document 1 is transparent, allowing it to be visually seen from the outside near its center. The transparent ball has internal markings indicating the target direction for dribbling and the direction for spinning the ball.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2015-159848

[0004] However, to improve ball control skills in ball games, it is important to make players aware of the ball's center of gravity, using the player's body's center of gravity as a reference. In this regard, placing a visually identifiable central element at the center of the ball is effective in making players aware of this center, and this central element needs to be maintained within the ball's internal space.

[0005] Typically, striking the center of the ball produces a high-precision no-spin ball. Alternatively, striking a point off-center produces a high-precision curveball or similar ball (hereinafter referred to as a variation ball). Therefore, if the center of gravity can be maintained at the center of the ball, training the player to use this center of gravity to become aware of the center and strike towards or off-center from it is a highly effective way to improve ball control.

[0006] Furthermore, to improve ball control technique for each type of ball to be served, it is even more important to clearly grasp the ball control position (hitting point) visually. In particular, to indicate the position deviating from the center of the ball, it is desirable for the center body to be able to move radially from the center of the ball. If the center body of the ball can be intentionally shifted radially from the center of the ball as a mark for the strike used to generate the variation, the player can clearly perceive visually the position where the strike for generating the variation should be applied, thus enabling them to train in a way that strikes towards the position deviating from the center of the ball, thereby contributing to the improvement of variation ball generation.

[0007] Furthermore, to enable players to experience advanced ball control techniques, it is crucial to handle the ball without applying inappropriate force (i.e., in a state of exhaustion). A means to clearly determine whether appropriate force has been applied to the ball is desirable. As such a means, a structure that allows the center body to move radially from the center of the ball upon impact is effective. This is because, according to this structure, the player can confirm the position of the center body after each impact. In this structure, as long as the setting is such that the center body does not move when the force applied by the player is appropriate, and moves when the force is inappropriate, the player can clearly grasp the force applied to the ball visually.

[0008] However, if the holding structure of the center body uses a rigid structure such as a support rod that fixes the center body relative to the skin part at the center of the ball, the center body cannot be moved radially from the center of the ball, thus limiting its ability to improve ball control techniques. Summary of the Invention

[0009] The present invention was made in view of the above aspects, and its object is to provide a ball for ball sports in which a held body, as a central body, is held near the center of the ball within an internal space and can be easily moved radially to make it eccentric.

[0010] One aspect of the present invention is a ball for ball sports, comprising: a spherical outer skin portion, at least a portion of which is formed to be transparent in such a way that the interior space can be visually confirmed from the outside; a cylindrical retaining portion, which extends within the interior space in such a way that it connects the two poles of the outer skin portion and has an inner enclosure space; and a held body, which is held within the inner enclosure space in such a way that it can be visually confirmed between the two poles, wherein the cylindrical retaining portion has a shape formed by a spiral twist between the two poles.

[0011] According to this structure, the cylindrical holding part, which is formed by a spiral twist between the two poles of the epidermis, can hold the holding body near the center of the sphere within the inner space and easily move it radially to make it eccentric. Attached Figure Description

[0012] Figure 1 This is a perspective view of a ball used in ball sports according to one embodiment of the present invention.

[0013] Figure 2 This is an exploded view of a ball used in ball sports according to an embodiment (in addition, for multiple boat-shaped parts with the same shape, only the parts with and without air holes are shown).

[0014] Figure 3 This is a schematic diagram illustrating the relationship between the cylindrical retaining part and the retained body in a ball used for ball sports according to an embodiment, and the structure for retaining the retained body at the center of the ball.

[0015] Figure 4 This is a diagram showing the relationship between the holding body and the communicating hole in the skin portion of a ball used in ball sports according to an embodiment.

[0016] Figure 5 This is a three-dimensional structural diagram of the cylindrical retaining portion of a ball used in ball sports, as described in the first modified form of the present invention, before twisting.

[0017] Figure 6 This is a three-dimensional structural diagram of the cylindrical retaining portion of a ball used in ball sports, as described in the second variation of the present invention, before twisting. Detailed Implementation

[0018] Hereinafter, specific embodiments of the ball for ball sports of the present invention will be described with reference to the accompanying drawings.

[0019] 1. The structure of balls used in ball sports

[0020] The ball 1 used in this embodiment is, for example, a soccer ball, volleyball, basketball, golf ball, baseball ball, tennis ball, etc., and is a spherical ball used in competitions and practice. The ball 1 is a transparent ball whose center is visually visible through its transparent outer layer. The ball 1 is used with high-pressure air sealed inside.

[0021] like Figure 1 and 2 As shown, the ball 1 for ball sports has an outer skin portion 10, a cylindrical retaining portion 20, and a retaining body 30.

[0022] Skin portion 10 is the part that constitutes the spherical outer skin of the ball 1 used in ball sports. Skin portion 10 is formed of a flexible material such as polyvinyl chloride. Skin portion 10 is configured such that at least a portion is transparent, allowing visual confirmation of the internal space (especially near the center of the ball) from the outside. Skin portion 10 is formed of a transparent or translucent material. Skin portion 10 is formed by pressing multiple parts together using heat or the like. Skin portion 10 is composed of a circular pole part 11 and a boat-shaped part 12.

[0023] The circular pole member 11 is a member disposed on the two opposing poles N and S of the ball for ball sports 1. The circular pole member 11 is formed in a circular shape. Two circular pole members 11 are provided corresponding to poles N and S. The boat-shaped member 12 is a member constituting the part of the ball for ball sports 1 other than poles N and S. The boat-shaped member 12 is formed in a boat shape. Multiple boat-shaped members 12 are provided (for example, six) arranged around the axis connecting the two poles N and S. Each boat-shaped member 12 is connected to the outer edge (specifically, the axial center of the outer edge) of the boat-shaped member 12 adjacent in the circumferential direction, and is connected to a part of the outer periphery of the circular pole member 11.

[0024] The outer skin portion 10 of the ball 1 for ball sports is formed by pressing together multiple boat-shaped parts 12 and two circular pole parts 11 of the N and S poles with their outer edges in contact. When the outer skin portion 10 is formed, an internal space 13 surrounded by the outer skin portion 10 is formed within the outer skin portion 10.

[0025] The skin portion 10 has an air hole 14 and a sealing plug 15. The air hole 14 is a hole through which external gas introduced into the internal space 13 and internal gas discharged from the internal space 13 to the outside can pass. The air hole 14 is provided in one of the multiple boat-shaped members 12. That is, the air hole 14 is provided at a location on the skin portion 10 that is different from the two poles N and S of the circular pole members 11. Specifically, the air hole 14 is formed in the boat-shaped member 12 near the middle of the two contact ends that are in contact with the two circular pole members 11, that is, near the axial middle.

[0026] The sealing bolt 15 is used to seal the air hole 14. The sealing bolt 15 is installed around the air hole 14 in the boat-shaped component 12. The sealing bolt 15 can be attached to and detached from the air hole 14. If the air hole 14 is sealed by the sealing bolt 15, the internal space 13 is closed. Thus, the ball 1 for ball sports remains in a state where air is sealed within the internal space 13. Furthermore, if high-pressure air is sealed into the internal space 13, then the internal space 13, i.e., the skin portion 10 and even the ball 1 for ball sports, is formed into a spherical shape.

[0027] The cylindrical holding portion 20 is the part that holds the held object 30. The cylindrical holding portion 20 is constructed using a cylindrical component and can form an inner enclosure space 21. The cylindrical holding portion 20 is formed to extend axially in a manner connecting the two poles N and S. The inner enclosure space 21 can enclose and hold the held object 30. The cylindrical holding portion 20 is formed of a shape-adaptable material, such as flexible polyvinyl chloride. Alternatively, the cylindrical holding portion 20 can also be formed of cloth or paper, as long as it encloses and holds the held object 30. The cylindrical holding portion 20 is configured such that at least a portion is transparent, allowing visual confirmation of the interior of the inner enclosure space 21 (especially near the center of the sphere) from the outside. The cylindrical holding portion 20 is formed of a transparent or translucent material.

[0028] Furthermore, the cylindrical retaining part 20 can also be formed of an elastic, stretchable material, as long as it can hold the retained body 30. The cylindrical retaining part 20 maintains a relatively small diameter when the retained body 30 is not inserted into the inner enclosure space 21, and can extend radially outward when the retained body 30 is inserted into the inner enclosure space 21. In addition, it can also be twisted into a spiral shape.

[0029] Alternatively, the cylindrical retaining portion 20 can be formed into a cylindrical shape, for example, by rolling up a sheet-like square component and pressing its circumferential ends together. Alternatively, it can be formed into a cylindrical shape by connecting and pressing multiple sheet-like square components circumferentially together. Figure 2 As shown, the cylindrical retaining portion 20 is formed in such a way that, in the state where it is not twisted into a spiral shape between the two poles N and S within the internal space 13 of the outer skin portion 10, the diameter R1 of the inner space 21 (specifically, the inner diameter of the cylindrical retaining portion 20) remains constant regardless of its axial position. Furthermore, the diameter R1 of the inner space 21 refers to the diameter of the cylindrical retaining portion 20 in its basic posture before being twisted between the two poles N and S.

[0030] The cylindrical retaining portion 20 is formed such that the retained body 30 can move axially within the inner enclosure space 21. Specifically, the cylindrical retaining portion 20 is formed such that the diameter R1 of the inner enclosure space 21 is greater than or equal to the outer diameter Rb of the retained body 30 (preferably larger than its outer diameter Rb) (see reference). Figure 3 The held body 30 can move within the inner enclosure 21 not only when the cylindrical holding part 20 is not twisted between the two poles N and S, but also when it is twisted. The cylindrical holding part 20 has the following structure: each of its two cylindrical ends is open, and the held body 30 can be inserted into the inner enclosure 21 from the cylindrical end.

[0031] A cylindrical retaining portion 20 is disposed within the internal space 13 of the outer skin portion 10. The cylindrical retaining portion 20 extends within the internal space 13 in a manner connecting the two poles N and S of the outer skin portion 10. The cylindrical retaining portion 20 is formed as part of the ball 1 for ball sports by pressing the edges of its respective cylindrical ends against the inner surface near the joint of the circular pole member 11 and the boat-shaped member 12 of the outer skin portion 10. The internal space 13 of the outer skin portion 10 is isolated from and does not communicate with the inner enclosure space 21 of the cylindrical retaining portion 20.

[0032] The cylindrical retainer 20 encloses and holds the retaining body 30 within the inner enclosure 21 in a manner that allows visual confirmation near the center between the two poles N and S of the outer skin portion 10. The cylindrical retainer 20 is pressed against the inner surface near the joint between the circular pole member 11 and the boat-shaped member 12 in a spiral-shaped configuration between the two poles N and S of the outer skin portion 10. After the ball 1 for ball sports is manufactured, as... Figure 1 and Figure 3 As shown, the cylindrical holding part 20 has a shape formed by spiral twisting between the two poles N and S of the skin part 10.

[0033] The torsion angle of the cylindrical retainer 20 is set such that it covers approximately the entire surface of the held body 30 between the two poles N and S. Furthermore, the torsion angle is set such that when the ball 1 is used in the internal space 13 with an air pressure exceeding a specified level, radial movement of the held body 30 within the inner enclosure 21, held between the two poles N and S of the outer skin portion 10 (particularly near the center connecting the two poles N and S), is suppressed; and when the air pressure in the internal space 13 is below a specified level, radial movement of the held body 30 within the inner enclosure 21 is possible by the force of a human hand. Additionally, the torsion angle is set such that, relative to the use of the ball 1, i.e., the vibration of the held body 30 within the inner enclosure 21, the durability of the cylindrical retainer 20 is maintained at a high level until the cylindrical retainer 20 breaks.

[0034] Furthermore, the torsion angle between the two poles N and S is preferably 135° to 270° and more preferably 135° to 225°. In particular, in terms of improving the durability of the cylindrical retaining portion 20, this torsion angle is preferably around 180°.

[0035] Here, in ball sports, the player's ability to relax and handle the ball 1 is crucial for improving ball control techniques. That is, if the force applied by the player during the strike to the ball 1 is inappropriate, the player will find it difficult to control the ball. Even when striking the ball 1 with the same magnitude of force, the ease of movement of the held body 30 within the inner space 21 varies correspondingly to the aforementioned torsion angle. Specifically, a smaller torsion angle facilitates movement, while a larger torsion angle makes movement less likely.

[0036] Therefore, the aforementioned torsion angle is set to a boundary value such that when the ball 1 is used with the air pressure within the internal space 13 within an appropriate range and is struck with an appropriate force, the held body 30 within the inner space 21 does not easily move radially. On the other hand, when the ball 1 is struck with a force exceeding this appropriate force, the held body 30 within the inner space 21 moves radially. Based on this torsion angle setting, when the ball 1 is struck with a force exceeding the appropriate force, the held body 30 within the inner space 21 moves radially. Therefore, by confirming the position of the held body 30 within the inner space 21 after the player has handled the ball 1, it is possible to confirm whether the player's strike to the ball 1 was accompanied by an appropriate force.

[0037] The held body 30 is a component disposed within the internal space 13 near the center of the ball 1 used in ball sports. The held body 30 is held within the inner space 21 of the cylindrical holding part 20 in a manner that allows for visual confirmation between the two poles N and S. Furthermore, the held body 30 may be a sphere for easy movement within the inner space 21, or conversely, a cube, a doll imitating a person or animal, etc., for difficulty in movement within the inner space 21.

[0038] The retainer 30, configured as a ball for ball sports, allows the player to visually identify the ball from the outside. For example, the retainer 30 is preferably colored, such as red or fluorescent. The retainer 30 is formed from materials such as cork, synthetic resin, or plastic. The retainer 30 can be a hollow structure made of plastic, like a ping-pong ball, or it can be a rubber tube that can be filled with air.

[0039] The outer skin portion 10 has a communicating hole 16. The communicating hole 16 is a hole that allows the inner enclosure 21 of the cylindrical retaining portion 20 to communicate with external gas. The communicating holes 16 are respectively provided on the circular pole members 11 at the N and S poles. Furthermore, the communicating hole 16 can be located at the center of the circular pole member 11, but it can also be located at a position offset from the center. Figure 4 As shown, the connecting hole 16 has a diameter R2 that is smaller than the outer diameter Rb of the held body 30.

[0040] The connecting hole 16 has the following functions: it prevents the held body 30 from flying outward from the inner enclosure 21 of the cylindrical holding part 20, and allows air to enter and exit between the inner enclosure 21 and the external gas when the held body 30 moves within the inner enclosure 21. In addition, the connecting hole 16 has the following function: during the manufacturing stage of the ball 1 for ball sports, when the cylindrical holding part 20 is twisted between the two poles N and S, compared with the structure in which the connecting hole 16 is not provided in the skin part 10, the axial position of the twist between the N pole and the S pole does not produce an extreme offset.

[0041] 2. The function and effect of balls in ball sports

[0042] In the ball 1 for ball sports having the above-described structure, the retaining body 30 is enclosed and held within the inner enclosure space 21 of the cylindrical retaining portion 20. The retaining body 30 is held in place by the cylindrical retaining portion 20 being twisted into a spiral shape between the two poles N and S of the outer skin portion 10, thus making approximately uniform contact with the surface of the retaining body 30. For example, if the retaining body 30 is positioned near the center of the line segment connecting the two poles N and S of the outer skin portion 10, while held within the inner enclosure space 21, it can be visually identified from the outside of the ball 1 near the center between the two poles N and S of the outer skin portion 10.

[0043] Players can visually identify the held part 30, held near the center of the ball by the tubular holding part 20, through the outer skin portion 10 and the tubular holding part 20 while handling the ball 1. Therefore, according to the ball 1, players handling the ball 1 can visually identify the held part 30 positioned near the center of the ball from the outside of the ball 1 through the transparent outer skin portion 10 and the tubular holding part 20, thereby enabling players to handle the ball while aware of its center.

[0044] Furthermore, in footballs of typical hardness, frequent heading can become a significant physical obstacle for players. In contrast, when a ball for ball sports is used for heading practice in football, it is possible to train ball control by using a highly safe material and focusing on the center of the ball, thus improving ball control skills while ensuring high player safety.

[0045] A ball used in ball sports can be handled by a player as a ball if the internal space 13 of the outer skin portion 10 is filled with air at a predetermined or higher pressure. Furthermore, as described above, the internal space 13 of the outer skin portion 10 is isolated from and does not communicate with the inner space 21 of the cylindrical retaining portion 20. Therefore, when the internal space 13 of the cylindrical retaining portion 20 is filled with high-pressure air, the high-pressure air will not flow from the internal space 13 into the inner space 21. On the other hand, the inner space 21 is always connected to the outside via the connecting hole 16. Therefore, it is possible to prevent the high-pressure air in the internal space 13 from leaking from the inner space 21 to the outside.

[0046] Furthermore, in the above-described configuration, when high-pressure air is not sealed within the internal space 13, the cylindrical retaining portion 20 remains in a spirally twisted state between the two poles N and S of the skin portion 10. Conversely, when high-pressure air is sealed within the internal space 13, the outer surface of the cylindrical retaining portion 20 is exposed to the high-pressure air from the internal space 13 throughout its entire circumference, and the inner surface of the cylindrical retaining portion 20 is exposed to atmospheric pressure air from the inner enclosure space 21 throughout its entire circumference. In this case, the cylindrical retaining portion 20 does not deform and remains in a spirally twisted state between the two poles N and S. Therefore, regardless of whether high-pressure air is sealed within the internal space 13, it is maintained in a spirally twisted state between the two poles N and S of the skin portion 10.

[0047] According to the structure of the cylindrical retaining part 20, when air at a predetermined or higher pressure is sealed in the internal space 13, the torsional state of the cylindrical retaining part 20 can hold the retained body 30 in a way that prevents it from moving radially within the inner enclosure space 21. Furthermore, when air at a predetermined or higher pressure is not sealed in the internal space 13, with air discharged from the internal space 13 and the back side of the skin portion 10 close to the surface of the cylindrical retaining part 20, the retained body 30 can be easily moved radially from the center of the skin portion 10 within the inner enclosure space 21 by hand from the outside of the skin portion 10.

[0048] In the ball 1 used for ball sports, when the internal space 13 is not sealed with high-pressure air, the holding body 30 is held within the inner space 21 of the cylindrical holding part 20, and can be moved radially within the inner space 21 by hand from the outside of the outer skin part 10. Furthermore, if high-pressure air is sealed into the internal space 13 while the holding body 30 has moved radially from the center of the ball, the holding body 30 is maintained in an off-center state, which can be visually confirmed from the outside. In this case, the ball 1 can be handled by the player while the holding body 30 is off-center, and handling the ball 1 in this state can impart irregular movements to the player's handling.

[0049] In this way, according to the ball 1 for ball sports, the holding body 30 can be easily held near the center of the ball in an eccentric manner within the internal space 13 of the outer skin portion 10, and the player can visually confirm the holding body 30 within the inner enclosure space 21, thereby easily conveying to the player the movements that may occur in the ball 1 corresponding to the position of the holding body 30.

[0050] Furthermore, the tubular retaining portion 20 is twisted into a spiral shape within the internal space 13 of the outer skin portion 10 between the two poles N and S of the outer skin portion 10, but extends in a manner connecting the two poles N and S. Therefore, the player can identify the tubular retaining portion 20 as the axis connecting the two poles N and S of the ball 1, making it easy to handle the ball 1.

[0051] Furthermore, as described above, the torsion angle of the cylindrical retaining portion 20 is set to a boundary value such that when the ball 1 is struck with an appropriate force, the retained body 30 within the inner enclosure 21 does not easily move radially, while when the ball 1 is struck with a force exceeding the appropriate force, the retained body 30 within the inner enclosure 21 moves radially. According to this structure, when the force applied to the ball 1 is appropriate, the retained body 30 within the inner enclosure 21 does not move radially; when the force applied to the ball 1 exceeds the appropriate force, the retained body 30 within the inner enclosure 21 moves radially.

[0052] Therefore, by confirming the position of the held body 30 within the inner enclosure 21 after each time a player handles the ball 1, it is possible to subsequently confirm whether the player applied excessive force to the ball 1. Thus, based on the ball 1, it is possible to train the player on the force applied to the ball 1, that is, to train the player to handle the ball 1 with appropriate force, thereby contributing to the improvement of ball control skills.

[0053] Furthermore, if the ball 1 for ball sports is handled while the holding body 30 is held at the center of the ball within the inner enclosure 21, the player can be trained to be aware of the ball's center through the holding body 30 and to strike the ball towards or away from the center, thus providing efficient training to improve ball control skills. On the other hand, if the ball 1 for ball sports is intentionally handled while the holding body 30 is intentionally held away from the center of the ball within the inner enclosure 21, the player can be made aware of the position away from the center of the ball through the holding body 30 as the position to strike to generate a variation of the ball, thereby training by striking towards this offset position, which can help improve variation of the ball.

[0054] Furthermore, the torsion angle between the two poles N and S of the cylindrical retainer 20 is between 135° and 270°. In particular, in the configuration with a torsion angle of around 180°, the durability of the cylindrical retainer 20 can be improved when used with ball 1 for ball sports compared to configurations with other torsion angles.

[0055] Furthermore, the inner enclosure space 21 of the cylindrical holding portion 20 communicates with the external gas via a communication hole 16 provided in the circular pole member 11 of the outer skin portion 10. According to this configuration, when the held body 30 is moved radially within the inner enclosure space 21 by hand, air can pass between the inner enclosure space 21 and the external gas. Therefore, unlike configurations without the communication hole 16, it is possible to prevent internal pressure deviations between the spaces within the inner enclosure space 21 separated by the held body 30 during movement. Specifically, it is possible to prevent the space within the inner enclosure space 21 relative to the held body 30 from becoming high pressure on the side where the held body 30 moves and low pressure on the opposite side, thus facilitating radial movement of the held body 30.

[0056] Furthermore, based on the structure of the inner enclosure 21 with the connecting hole 16, when the cylindrical retaining part 20 is twisted between the two poles N and S during the manufacturing stage of the ball 1 for ball sports, compared to a structure where the connecting hole 16 is not provided in the outer skin part 10, the axial position of the twist between the N and S poles can be prevented from extreme deviation. Therefore, the retaining function of the cylindrical retaining part 20 for holding the held body 30 can be fully utilized.

[0057] 3. Deformation method

[0058] However, in the above embodiment, the connecting holes 16 are respectively provided on the circular pole members 11 arranged at the two poles N and S of the skin portion 10. However, the present invention is not limited to this. As long as air can enter and exit between the inner enclosure space 21 and the external gas, the connecting holes 16 may be provided only on either of the circular pole members 11 arranged at the two poles N and S.

[0059] Furthermore, in the above embodiment, the cylindrical retaining portion 20 is configured to extend in such a way that the two poles N and S of the respectively arranged circular pole members 11 of the skin portion 10 are connected to each other. However, the present invention is not limited to this, and the cylindrical retaining portion 20 may also be configured to extend in such a way that the two poles of the skin portion 10 other than the two poles N and S of the respectively arranged circular pole members 11 (and these two poles are provided in the boat-shaped member 12) are connected to each other. According to this variation, the portions where the circular pole members 11 of the skin portion 10 are pressed against the boat-shaped member 12 and the portions where the boat-shaped member 12 is pressed against the cylindrical retaining portion 20 can be separated by distance and not approach each other, thus preventing a decrease in the rigidity of the ball 1 for ball sports.

[0060] Furthermore, in the above embodiment, the two poles N and S at both ends of the cylindrical retaining portion 20, which are respectively disposed with circular pole members 11 and pressed against each other, are positioned such that the line segment connecting the two poles N and S passes through the center of the sphere, and the cylindrical retaining portion 20 extends through the center of the sphere and connects the two poles N and S in a straight line. However, the present invention is not limited to this, and the two poles at both ends of the cylindrical retaining portion 20 in the skin portion 10 may also be positioned such that the line segment connecting the two poles does not pass through the center of the sphere. However, in this case, the cylindrical retaining portion 20 preferably extends through the center of the sphere and connects the two poles in a curved or broken line. In addition, in this modified embodiment, in order to restrict the movement of the cylindrical retaining portion 20 near the center of the sphere within the internal space 13 and fix it, it is preferable to provide a support body connecting the cylindrical retaining portion 20 and the skin portion 10 (specifically, the back side of the skin portion 10).

[0061] Furthermore, in the above-described embodiment, the ball 1 for ball sports includes a cylindrical holding portion 20 for holding the held body 30, which is constructed using a component formed in a cylindrical shape. However, the present invention is not limited to this, and the cylindrical holding portion 20 may also be constructed using a component formed in a multi-sided cylindrical shape, such as a four-sided cylindrical shape.

[0062] Furthermore, in the above embodiment, the internal space 13 of the skin portion 10 is isolated from the inner enclosure space 21 of the cylindrical holding portion 20 and is not interconnected. However, the present invention is not limited to this, and the internal space 13 of the skin portion 10 and the inner enclosure space 21 of the cylindrical holding portion 20 may also be interconnected. However, in this modified configuration, in order to prevent air from being discharged from the internal space 13 to the outside through the inner enclosure space 21, the aforementioned communication hole 16 needs not be provided in the circular pole component 11.

[0063] In this deformation mode, such as Figure 5 As shown, the ball 1 for ball sports may also include a cylindrical holding portion 100 for holding the held body 30. This cylindrical holding portion 100 is integrally formed into a cylindrical shape by arranging rod-shaped components 101, such as round bars or square bars, in a circumferential direction. Furthermore, this cylindrical holding portion 100 may be configured such that the components 101 are spaced apart circumferentially (and the gap is smaller than the outer diameter Rb of the held body 30 to prevent the held body 30 from passing through) and joined to the cylindrical strip-shaped component 102 at its axial end, and pressed against the skin portion 10 side when twisted.

[0064] Furthermore, in the above embodiment, the cylindrical retaining portion 20 is formed in a cylindrical shape such that, in a state where it is not twisted into a spiral shape between the two poles N and S, the diameter R1 of the inner enclosure space 21 remains constant regardless of its axial position. However, the present invention is not limited to this, such as... Figure 6As shown, the ball 1 for ball sports may also have a cylindrical holding part 200 for holding the held body 30. The cylindrical holding part 200 is formed into a cylinder with the diameter R1 of the inner space 21 changing in relation to the axial position when it is not twisted into a spiral shape between the two poles N and S.

[0065] In the aforementioned modification, the cylindrical retaining portion 200 is configured such that the retained body 30 can move axially within the inner enclosure space 21. The cylindrical retaining portion 200 has a concave-convex portion 201. The concave-convex portion 201 is a portion where the diameter R1 of the inner enclosure space 21 varies correspondingly with the axial position. The concave-convex portion 201 is configured such that the inner surface of the cylindrical retaining portion 200 easily maintains the shape of the retained body 30 along the outer surface of the retained body 30.

[0066] The concave-convex portion 201 has a convex portion 201a that protrudes radially outward and a concave portion 201b that is recessed radially inward relative to the convex portion 201a. The convex portion 201a and the concave portion 201b are continuously arranged in the axial direction. The smallest diameter of the inner diameter of the cylindrical retaining portion 200, i.e., the diameter R1 of the inner enclosure space 21 (specifically, the inner diameter of the concave portion 201b), is greater than or equal to the outer diameter Rb of the retained body 30. The retained body 30 can move within the inner enclosure space 21 not only when the cylindrical retaining portion 200 is not twisted between the two poles N and S, but also when it is twisted.

[0067] Furthermore, to improve ball control, the protrusions 201a and 201b can be shaped to facilitate judgment after a strike whether the player has applied appropriate force to the ball 1. The protrusions 201a and 201b can also have inclined surfaces that extend obliquely relative to the axial direction. Additionally, the top of the protrusion 201a and the base of the concave portion 201b can be formed at acute angles, or they can be formed smoothly. For improved ball control, the angle formed by the top of the protrusion 201a and the angle formed by the base of the concave portion 201b are preferably adjusted to angles most suitable for judging after a strike whether the player has applied appropriate force to the ball 1.

[0068] Based on this modified structure, the held body 30 can move axially within the inner space 21 of the cylindrical holding portion 200. Furthermore, the held body 30 is easily held within the inner space 21 of the cylindrical holding portion 200 by the concave-convex portion 201, thus enabling a ball for sports where the held body 30 is difficult to move radially or axially even during player training. Additionally, after a player strikes the ball for sports 1, the position of the held body 30 within the inner space 21 can be visually confirmed, making it easy to determine whether the player's force has been applied appropriately.

[0069] Furthermore, the concave and convex portions 201, for example, Figure 6As shown, it is also possible to have a single protrusion 201a positioned near the axial center, with two recesses 201b positioned axially separated from the protrusion 201a. With this configuration, the held body 30 is easily held near the axial center of the inner space 21, i.e., near the center of the ball, thus enabling the ball 1 for ball sports to be handled while the player is aware of the ball's center.

[0070] Alternatively, the protrusion 201 can be configured such that the protrusion 201a is positioned near the axial center, instead of as described above, and is positioned offset towards the axial end. Alternatively, the protrusion 201 can be configured such that the protrusion 201a is axially separated at two or more locations, and a recess 201b is provided on both axial sides of each protrusion 201a. Furthermore, the protrusion 201 can be configured as follows: Figure 6 The portion shown is only provided on a part of the entire circumference of the cylindrical portion 200; alternatively, it may be provided throughout the entire circumference. Furthermore, the protrusions and recesses 201 may be spirally shaped around the axis between the two poles N and S of the cylindrical portion 200.

[0071] The cylindrical retaining portion 200 only needs to have a concave-convex portion 201 with a diameter R1 of the inner enclosing space 21 that varies in relation to the axial position. For example, the circumferential end of the sheet member constituting the cylindrical retaining portion 200 can be cut out from a square shape and then pressed together with the cut circumferential ends to form a concave-convex portion 201 of the desired shape.

[0072] Furthermore, the present invention is not limited to the above-described embodiments and modifications, and various changes can be made without departing from the spirit of the present invention.

[0073] Explanation of reference numerals in the attached figures

[0074] 1…ball for ball sports; 10…outer skin; 11…circular pole component; 12…boat-shaped component; 13…internal space; 14…air hole; 15…sealing plug; 16…connecting hole; 20, 100, 200…cylindrical retaining part; 21…inner space; 30…retained body; 201…concave and convex parts.

Claims

1. A ball for a ball game, characterized in that have: The spherical epidermis is at least partially made transparent in a way that allows the interior space to be visually confirmed from the outside. A cylindrical retaining portion is configured to extend within the internal space in a manner connecting the two poles of the outer skin portion, and to form an inner enclosing space; as well as The object is held within the enclosing space in a manner that allows for visual confirmation between the two poles. The cylindrical retaining portion has a shape formed by a spiral twist between the two poles. The held object is capable of moving between the two poles within the enclosing space and is capable of being held at the center of the sphere and at an off-center position deviating from the center of the sphere.

2. The ball for ball sports according to claim 1, characterized in that, The cylindrical retaining part is twisted between the two poles to a range of 135° to 270°.

3. The ball for ball sports according to claim 1 or 2, characterized in that, The cylindrical retaining portion has concave and convex portions that correspond to the change in diameter and axial position of the inner enclosing space before being twisted.

4. The ball for ball sports according to any one of claims 1 to 3, characterized in that, The outer skin portion has a communicating hole, which allows the inner space of the cylindrical retaining portion to communicate with external gas. The connecting hole has a diameter smaller than the outer diameter of the held body.

5. The ball for ball sports according to any one of claims 1 to 4, characterized in that, The outer skin portion has air holes located at positions different from the two poles, allowing external gas introduced into the internal space and internal gas discharged from the internal space to the outside to pass through. It has a removable sealing bolt that can close the air hole.

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