Items used in Kendama

Abstract

To provide an article capable of assisting step-by-step exercise of skills of a cup and ball.SOLUTION: The article has a hole into which a sword is insertable and a string fastening part where a string can be fastened, and the article is used as a flying object and / or a grip in a cup and ball. The article has a specific easy rotation axis by having a shape anisotropy, and the hole is provided such that the center line of the hole is generally perpendicular to the shortest easy rotation axis among easy rotation axes.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an article used for "kendama", for example, an article used when practicing conventional "kendama" tricks or when performing unconventional "kendama" tricks. [Background technology]

[0002] A traditional Japanese toy called a "kendama" has been known for some time (see, for example, Patent Document 1). FIG. 8 shows the structure of a typical "kendama." A typical "kendama" is composed of a "ken 1" provided with a large plate 4, a small plate 5, a middle plate 6, etc., each of which has a different diameter, and a "ball 10" which is a spherical body having a predetermined diameter and which is connected to the "ken 1" by a string 9, and is used primarily for the purpose of enjoying the technique of holding the side of the "ken 1" and catching the "ball 10" with the large plate 4, etc.

[0003] The "ken 1" is constructed by inserting a drum-shaped "dish body 3" into a "ken shaft 2". A "middle dish 6" is provided at the bottom of the "ken shaft 2", and a "large dish 4" and a "small dish 5" are provided on both sides of the "dish body 3", and each dish is capable of holding a "ball 10" by the ring portion formed by its circumference. The tip of the "ken shaft 2" is called the "ken tip 7", and by inserting this "ken tip 7" into the "hole 11" of the "ball 10" described below, the "ball 10" can also be held at the tip of the "ken 1".

[0004] The "ball 10" is formed in a generally approximately spherical shape so that it can be held well by the plates on the "ken 1." The diameters of the rings that form the periphery of each plate on the "ken 1" are made in various sizes within a range that does not exceed the diameter of the "ball 10," and they are distinguished by names such as "large plate 4," "medium plate 6," and "small plate 5" depending on the size of the rings, and by changing the degree of difficulty of catching the "ball 10" on each plate, the added value of the toy is increased. The "ball 10" has a "hole 11" into which the "tip 7" can be freely inserted, so that it can be held by the "tip 7" of the "ken 1." In addition, the opening of the "hole 11" is generally provided with a "countersink 12" of an appropriate size to make it easier to insert the "tip 7."

[0005] Between the bottom of the hole 11 and the surface of the ball 10, a small through-hole called a "thread hole 13" is provided as a thread fastening section for fastening a thread to the ball 10, and the ball 10 can be suspended by thread 9, which has a bead 14 or the like at one end to prevent it from slipping out, passed through the "thread hole 13" from the bottom side of the hole 11. The other end of the thread 9 is then fixed to the "thread hole 8" provided in the ken 1, thereby connecting the ball 10 to the ken 1. In addition, as shown in FIG. 8, by providing a "thread hole 13" in the ball as a thread fastening portion on the opposite side of the "hole portion 11," when the ball is suspended by a thread, the hole portion opens approximately vertically downward.

[0006] There are various ways to play with "kendama" (tricks), and the above "ken 1" and "ball 10" are used interchangeably as a held object or a flying object. In addition to tricks in which the performer holds "ken 1" and uses "ball 10" as a flying object and catches "ball 10" with "plates 4-6" or "tip 7" of "ken 1", tricks in which the performer holds the side of "ball 10" and flies "ken 1", and catches "ken 1" on the surface or "hole 11" of "ball 10", each of which has a different level of difficulty. Furthermore, it is also possible for the performer to fly the whole "kendama" while holding either "ken 1", "ball 10", or string 9, first catch and hold "ken 1", and then catch "ball 10" in various ways with "ken 1", and perform other stunts using the whole "kendama" as a flying object.

[0007] The most basic way to play with "kendama" (technique) is for the performer to hold "ken 1" by grasping "ken axis 2", and as shown in Figure 8, "ball 10" is suspended from string 9. By applying a certain tension to string 9 via "ken 1", "ball 10" is sent flying, and then "ball 10" is caught by "large plate 4" (the technique known as "large plate"). In a technique such as "large plate" in which the "ball" is caught by the "plate", for example, by positioning "ken 1" so that the center of gravity of the "ball" is inside the ring that is the outer periphery of the corresponding "plate", it is possible to catch the "ball" with the "plate". In a technique in which the "ball" is caught by the "plate" in this way, whether or not the "ball" can be caught is determined mainly by the relative positions of the "plate" and the "ball", so it is possible to complete the technique regardless of the relative positions of the "hole 11" provided in the "ball" and the "plate".

[0008] On the other hand, when the performer grasps the "kenjiku 2" and inserts the "kentip 7" into the "hole 11" of the "tama 10" to catch it, in addition to considering the relative positions of the "kentip 7" and the "tama 10", it is necessary to roughly align the directions of the "hole 11" and the "kentip 7" at the moment of the catch, which creates difficulties when compared to catching with the "sara" mentioned above. In other words, when using a "sara", the technique can be completed by simply paying attention to the relative positions between the "sara" and the "tama", whereas when using the "kentip 7", it is necessary to pay attention to the relative positions with the "tama" as well as the opening direction of the "kentip" and the "hole".

[0009] In relation to the difficulty, the "tomeken" is known as the easiest technique to catch the "ball" with the "tip of the ken." The "tomeken" is a technique in which the "ball" is suspended by a string 9 with the "hole" facing vertically downward, and then the "ball" is thrown upwards without rotating (spinning) to keep the "hole" facing vertically downward, and the "tip of the ken" is inserted into the "hole." In "Tomeken," by mastering the technique of flying the "ball" roughly upwards without rotating, the technique can be completed by paying attention to the relative positions of the "tip of the ken" and the "ball," essentially the same as when using a "sara," so even beginners can perform it relatively easily.

[0010] In contrast, for example, in a technique called "Furiken," compared to the above-mentioned "Furiken," the performer is required to deliberately make the "ball 10" fly forward so that it descends when starting the technique, and as a result, the direction of the "hole 11" changes, making it difficult to insert the "tip of the ball" into this "hole" to catch it. The difficulty of the "Furiken" technique is considered as follows. As described above, the "ball 10" is suspended by the string 9 passed through the "thread hole 13" at the bottom of the "hole 11", and begins to fly or move due to the driving force applied through the string. In addition, in a technique that starts with the "ball 10" suspended by the string 9, the subsequent movement of the "ball" is determined by the force applied to the "ball" through the string 9 while tension is applied to the string 9, which is essentially immediately after the start of the technique.

[0011] In other words, immediately after starting the technique, the performer must make the "ball" fly to a position where he or she can receive it simply by adjusting the amount of force transmitted to the string 9 via the "ken," and at that position the performer must keep the opening direction of the "hole" within a specified range; and it is thought that the difficulty of mastering this is what makes "Furiken" so difficult to perform. To address the above-mentioned difficulties, for example, a simple color pattern on the surface of the "ball 10" has been applied to indirectly help the performer to sense the direction of the "hole 11," thereby helping beginners master the "furiken." However, it is still difficult to appropriately control the position of the "ball" and the opening direction of the "hole" by momentarily manipulating the "ball 10" via the string 9, and mastering techniques such as "furiken" is a major obstacle in the process of beginners improving. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] JP 2018-742 A Summary of the Invention [Problem to be solved by the invention]

[0013] For example, like training wheels that are commonly used in the process of mastering bicycle riding, it is effective for a beginner to use a means to appropriately alleviate some of the difficulty in the process of mastering a skill, allowing the beginner to gradually get the hang of it and gradually acquire the skill. On the other hand, in the past, there were no sufficient aids to gradually acquire the skill of "Furiken" and the like, and there was no way to acquire the skill other than trying to "Furiken" in one go. As a result, there are many cases where people give up on improving their "kendama" skills because they are unable to acquire the "Furiken" skill.

[0014] In view of the above circumstances, the main objective of the present invention is to provide an item that can assist in the gradual acquisition of skills by alleviating some of the difficulties involved in controlling the opening direction of the "hole 11" in the "ball 10" of a "furiken" or the like. Another objective is to provide an item that allows users to enjoy new, previously unseen "kendama" tricks by using the item. [Means for solving the problem]

[0015] In order to solve the above problems, the present invention provides the following article. <1> An article having a hole into which the tip of a kendama can be inserted and a string fastening part into which a string can be fastened, and used as a flying object and / or a gripping object in a kendama, said article having a specific axis of easy rotation due to its shape anisotropy, and said hole being arranged so that the center line of said hole is approximately perpendicular to the shortest axis of easy rotation among said axes. <2> The above-mentioned article has a ratio of 1.1 or more obtained by dividing the length of the axis of easy rotation that has the longest length passing through the article by the length of the axis of easy rotation that has the shortest length. <3> In the above-mentioned article, at least a portion of the wall surface constituting the hole is formed into a cylindrical shape centered on the center line of the hole. <4> The above-mentioned article has a countersunk portion at the opening of the hole. <5> The above-mentioned article has holes into which the tip of the finger can be inserted, the holes being provided on both ends of the article facing each other. <6> In the above-mentioned article, the thread fastening portion is provided at a position such that, when the article is suspended by a thread fastened to the thread fastening portion, the hole portion opens substantially vertically downward. <7> In the above-mentioned article, the thread fastening portion is provided at a position such that, when the article is suspended by a thread fastened to the thread fastening portion, the hole portion opens in a direction other than vertically downward. Effect of the Invention

[0016] The present invention contributes to the mastery of a method for controlling the rotational motion of a flying object in a kendama, and also provides new kendama techniques. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram illustrating a difference in the axis of easy rotation due to the shape of an article. [Diagram 2] 1A and 1B are diagrams showing the form of an article according to an embodiment of the present invention. [Diagram 3] 3 is a schematic diagram showing the movement of the object when the object shown in FIG. 2 is used as a flying object and a "fly-around" is performed. [Figure 4] 11A to 11C are diagrams showing the shape of an article according to another embodiment of the present invention. [Diagram 5] 11A to 11C are diagrams showing the shape of an article according to another embodiment of the present invention. [Figure 6] 11A to 11C are diagrams showing the shape of an article according to another embodiment of the present invention. [Figure 7] 11A to 11C are diagrams showing the shape of an article according to another embodiment of the present invention. [Figure 8]FIG. 1 is a diagram showing the structure of a typical "kendama." [Figure 9] This is a schematic diagram showing the movement of the "ball" during "furiken." DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The difficulty of tricks such as "Furiken" that require control of the opening direction of "hole 11" in "ball 10" is believed to be due to the necessity, as explained above, of simultaneously flying "ball 10" and guiding it to a position where the performer can receive it, and controlling the opening direction of "hole 11." Furthermore, the difficulty is exacerbated by the fact that these two operations must be performed by the simple action of momentarily applying tension via "ken 1" to the string 9 attached to one end of "ball 10."

[0019] Below, we will consider the behavior of the "ball 10" in the case of "Furiken" as an example. Figure 9 shows a schematic diagram of the ideal translational motion 21 and rotational motion 22 that should occur in the "ball" in the process of completing the "Furiken" technique. In "Furiken," the "ball" suspended vertically downward by a string 9 must first drop forward and then rise to a position above the "ken" where it can be received. In other words, when "Furiken," it is essential that the center of gravity of the "ball" perform a curved movement 21. Meanwhile, the driving force that causes the "ball" to perform the curved movement 21 is imparted to the "ball" via the string 9 attached to a "thread hole 13" that is provided away from the center of gravity of the "ball." As a result, the driving force applied to the "ball" also acts as a driving force that causes the "ball" to rotate 22 on its axis, and the "ball" begins to rotate 22 on its axis at the same time as the movement 21.

[0020] In order to complete the "Furiken" technique in which the "tip 7" facing upward is inserted into the "hole 11" to receive the "ball 10," it is necessary to achieve the ideal combination in which, as shown in Figure 9, the "ball" completes approximately one rotation 22 on its axis at the point when it reaches a position where the performer can receive it via its moving motion 21, so that the opening of the "hole 11" faces approximately downward.

[0021] In order to generate the above-mentioned rotational motion 22 of the "ball," it is necessary to appropriately control both the "axis of rotation (direction of rotation)" and the "speed of rotation" of the "ball." In other words, as shown in FIG. 9, the rotational motion 22 is required to have an appropriate rotational speed, with the center line of the "hole 11" moving within the plane (the plane of FIG. 9) along which the "ball" moves 21, with the axis perpendicular to the plane as the axis of rotation. However, when actually attempting to "fly" a "ken," the direction of the axis of rotation of the "ball" does not necessarily become as shown in FIG. 9. As a result, for example, the center line of the "hole 11" does not exist within the plane of FIG. 9, and problems such as the ball not being able to be caught by the "tip 7" facing approximately upwards arise.

[0022] In other words, to complete a "Furiken," it is necessary to generate an appropriate movement motion 21 for the "ball" by instantaneously applying a driving force via the string 9 fastened to the "ken 1," as well as a rotational motion 22 with an appropriate "axis of rotation" and "speed of rotation." The difficulty of controlling this is thought to be the reason why "Furiken" is so much more difficult to make, compared to a "large plate" or the like, which can be completed simply by making the appropriate movement motion.

[0023] Also, in so-called secret techniques, in which the shape of the opening of the "hole" of the "ball" is used to catch the "ball" with any part of the "ken" 1 other than the "tip 7", it is necessary to simultaneously control the movement 21 and rotation 22 of the "ball" just like in "furiken", and mastering this is essential for improving your "kendama" skills.

[0024] The inventors have conducted various studies on an article that can alleviate some of the difficulties in appropriately controlling the opening direction of the "hole 11" by controlling the rotational motion 22 in the above-mentioned "flying ken" and can assist in the gradual acquisition of the skill, and have found that by devising the shape of the "ball" used as the "flying object" that is the main part that is received in a kendama, the control of the rotational motion 22 becomes easier, and "flying ken" can be easily performed, leading to the present invention. By practicing using the article according to the present invention as the "ball (flying object)", the knack of performing "flying ken" can be acquired, and by practicing with gradually increasing difficulty, it becomes possible to gradually master "flying ken" using the original "ball".

[0025] (1) Features of the present invention FIG. 1 is a diagram for explaining the difference in the axis of easy rotation of an object due to the difference in shape. In FIG. 1, each object is made of a material having a uniform weight density. As shown in FIG. 1(a), when a spherical object is rotated, there is no specific "axis of easy rotation" that is likely to be the central axis of rotation due to the isotropic distribution of mass around the center (center of gravity) of the object, and rotation can occur equally regardless of which axis passing through the center (center of gravity) is used as the rotation axis.

[0026] On the other hand, for example, in the case of an article having shape anisotropy such as a cylindrical shape as shown in Fig. 1(b), a specific axis of easy rotation that allows stable rotation is determined according to the shape of the article, and when the article rotates without external constraint, the article rotates about the axis of easy rotation. In other words, in the case of the cylindrical shape shown in Fig. 1(b), the axis of easy rotation is limited to an axis (long axis 26) passing through the center of gravity of the cylinder and the centers of both bases, and an axis (short axis 25) passing through the center of gravity of the cylinder so as to be perpendicular to the long axis 26.

[0027] It is also known that even if rotational motion is imparted about an axis other than the major axis 26 and the minor axis 25, the axis of rotation is autonomously corrected due to the bias of the centrifugal force generated by the rotation, and the rotational motion converges to a rotational motion mainly about the minor axis 25. For this reason, it is difficult for the cylindrical article shown in Fig. 1(b) to perform stable rotational motion around an axis other than the major axis 26 and the minor axis 25, which are rotational axes on which the centrifugal forces generated when the article rotates are balanced, and the axes of rotation on which stable rotation is possible are limited to the major axis 26 and the minor axis 25.

[0028] The above tendency is not limited to the cylindrical shape shown in Fig. 1(b), and typically, any shape that has anisotropy due to a length in a specific direction being longer than in other directions, such as a prolate spheroid obtained by rotating an ellipse around its major axis, will have an easy axis of rotation determined by its shape and weight distribution. On the other hand, not having an easy axis of rotation is considered to be an inherent feature of a sphere.

[0029] In the present invention, among the axes of easy rotation possessed by an article, the axis having the longest length passing through the article is referred to as the long axis 26, and the axis having the longest length is referred to as the short axis 25. In addition, in the present invention, when describing the length of the axis of easy rotation passing through the article, the length means the length that the axis passes through the article when there is no hole or aperture such as the hole 11 provided in the outer shape (contour) of the article. That is, for example, in FIG. 6(a) shown below, the long axis 26 has a hole 11, but the length of the axis of easy rotation (long axis 26) having the longest length passing through the article is defined as the distance between the bottoms of the large plate 4 and the small plate 5, which are the contour of the article.

[0030] The shape of the "ball" used as a flying object in a typical kendama is approximated to a spherical object as shown in Fig. 1(a) above, and the "ball" spins around an axis with an appropriate directionality according to the direction of the force applied through the string 9, and there is practically no axis of easy rotation in the rotation that occurs in the "ball" when performing kendama tricks. As a result, the axis of rotation 22 that occurs in the flying "ball" in "flying ken" is not necessarily perpendicular to the plane of the trajectory of the "ball"'s moving motion 21 as shown in Fig. 9, making it extremely difficult to control the opening direction of the "hole 11" of the flying "ball". If the "hole" spins around the ball in a way that does not point downward near the position in front of the performer where the ball can be received, the ball cannot be received by the "tip 7" that faces upward.

[0031] An example of an embodiment of the present invention is shown in Figure 2. The article shown in Figure 2 is generally cylindrical in shape and has a "hole 11" on one bottom surface into which the "tip 7" can be easily inserted, and a ring-shaped "thread hole 13" on the other bottom surface for attaching a thread. The article shown in FIG. 2 has a generally cylindrical shape, and thus has an axis (long axis 26) passing through the center of gravity of the article and the centers of both bottom surfaces as well as an axis (short axis 25) that is perpendicular to the long axis 26 and passes through the center of gravity of the article, as in the case of the cylindrical shape shown in FIG. 1(b). In the article shown in FIG. 2, the "thread hole 13" for fastening the string is provided near the long axis 26, so it is difficult to cause rotation around the long axis 26 by the force applied by the string 9 fastened to the "thread hole 13". When the article is used as a flying object for a kendama, it essentially rotates around the short axis 25. The "hole 11" is provided so that its center line is approximately perpendicular to the short axis 25, so that the center line of the "hole 11" moves on the equator of rotation when the article rotates.

[0032] In other words, by using the article shown in Figure 2 as a "ball (projectile)" for "ken 1," the positional relationship between the axis of rotation of the projectile and "hole 11" is inevitably determined, making it easier to control the opening direction of "hole 11" compared to when a normal spherical "ball" is used.

[0033] FIG. 3 is a schematic diagram of a "furiken" technique in which the object shown in FIG. 2 is used as the flying object 15 and the object is swung forward. In FIG. 3, the plane formed by the trajectory of the moving motion 21 of the flying object 15 is included in the plane of the paper. As described above, the "furiken" technique is mainly composed of an acceleration process in which the flying object 15, which is suspended vertically by a string, descends forward and accelerates by applying a driving force (F) from a state in which tension is applied to the string, and an inertial process in which the flying object 15 ascends (moving motion 21) by the inertial force obtained by the flying object 15 during the acceleration process and guides it to a receivable position above the "ken," while at the same time rotating the flying object 15 on its own axis 22 to point the "hole 11" approximately downward.

[0034] When the article shown in FIG. 2 is used as flying body 15, the flying body 15 tends to rotate about its minor axis 25, and the centrifugal force accompanying the movement 21 of the flying body 15 makes it easy to maintain the center line of the "hole 11" that is provided approximately perpendicular to the rotation axis (minor axis 25) within the plane of the movement 21 of the flying body 15. This makes it easier for the performer to experience the "furiken" motion compared to when the spherical flying body shown in FIG. 9 is used.

[0035] For this reason, by using the article of the present invention as flying object 15 in a kendama, the performer does not need to pay attention to controlling the axis of rotation of flying object 15, but can complete the trick by paying attention only to the position of the flying object relative to the "tip of the kendama" and the opening direction of the "hole" within the plane from which the flying object is swung, making it easier to experience "Furiken."

[0036] Furthermore, when the article of the present invention is used as flying object 15 in a kendama, in comparison with a "ball," in addition to the above-mentioned appearance of an axis of easy rotation, the inertial force of rotational motion 22 of flying object 15 becomes larger, mainly due to the length of said axis of easy rotation, and it is believed that "furiken" can be performed more easily.

[0037] When objects with the same mass but different shapes are rotated at the same rotational speed, it is known that the object with more mass farther from the center of gravity has a larger inertial force. For example, when the masses of the sphere shown in Fig. 1(a) and the cylinder shown in Fig. 1(b) are the same and rotated, it is known that the inertial force of the rotation increases in the order of cylinder (long axis 26) < sphere < cylinder (short axis 25).

[0038] The above is believed to be because, when the flying object 15 is rotated from a restrained state with a given driving force, the response of the rotation to the applied driving force becomes gentler in the rotation about the minor axis 25 of a cylinder with a large inertia compared to the rotation of a sphere with the same mass, making it easier for the performer to adjust the applied driving force. This effect is also believed to make it easier to perform "Furiken" by using the article according to the present invention as a flying object.

[0039] (2) Shape of the article according to the present invention The article of the present invention is characterized in that its shape is not isotropic (such as a sphere), but has shape anisotropy, characterized in that its length in a specific direction is longer than in other directions, and as a result has a specific axis of easy rotation, and the center line of "hole 11" into which the "tip 7" of "ken 1" used in a kendama can be inserted is arranged so as to be approximately perpendicular to the axis (minor axis 25) of the axes of easy rotation that has the shortest length passing through the article.

[0040] As explained above, it is known that when a driving force that causes a rotational motion in a random direction is applied to an article having shape anisotropy, the rotational motion tends to converge to a rotational motion around the "shortest axis of easy rotation" where the inertial force of the rotation is the largest. The present invention utilizes this property, and by using the article according to the present invention as the flying object 15 of a Kendama, the "hole 11" having a direction approximately perpendicular to the "shortest axis of easy rotation" rotates on the equator of the rotational motion, making it easy to control the position of the opening.

[0041] The article according to the present invention can have any suitable shape, so long as it has a plurality of axes of easy rotation around which the inertial forces differ when rotating due to the anisotropy of the shape. On the other hand, when focusing on the ratio between the length of the axis of easy rotation (major axis 26) that has the longest length passing through the article and the length of the axis of easy rotation (minor axis 25) that has the shortest length, by appropriately setting this ratio, it is possible to adjust the controllability of the rotational motion when the article is used as a flying object 15 in a kendama, and the difficulty of performing "furiken" or the like can be changed.

[0042] In other words, by making the ratio of the length of the axis of easiest rotation (major axis 26) that has the longest length passing through the article to the axis of easiest rotation (minor axis 25) that has the shortest length about 1.1 or more, the article will tend to rotate around the minor axis 25, compared to a spherical "ball" that has no specific axis of easy rotation, and this makes it easier to maintain the opening position of hole 11 of flying body 15, which has a centerline that is approximately perpendicular to minor axis 25, at the rotation equator.

[0043] Furthermore, by making the ratio of the long axis 26 to the short axis 25 1.5 or more, or 2 or more, the shape anisotropy of the article is increased, and the axis of rotation when rotating in a normal kendama is substantially limited to the short axis 25, making it easier to maintain the opening position of the hole 11 of the flying object 15 at the equator of rotation. Furthermore, by making the ratio of the long axis 26 to the short axis 25 3 or more, or 4 or more, the article has a substantially rod-like shape, and the inertial force when rotating around the short axis 25 becomes large, making it easier to control the speed of the rotation, making it easier to perform "furiken" and the like.

[0044] In addition, in the article according to the present invention, it is preferable that the rotational motion of the article is easily converged to the rotational motion around the short axis 25 by imparting a predetermined rotational symmetry to the shape around the long axis 26. In particular, by making the center line of the "hole 11" substantially coincident with the axis of easy rotation (long axis 26) that has the longest length passing through the article among the axes of easy rotation of the article, the symmetry of the entire article is improved and the rotational motion of the article can be stabilized. By making the symmetry of the article when viewed from the direction of the long axis 26, for example, two-fold symmetry, three-fold symmetry, four-fold symmetry, five-fold symmetry, six-fold symmetry, etc., the long axis 26 and the short axis 25 are substantially perpendicular to each other, making it easier to control the rotation of the article.

[0045] In particular, by making the cross section perpendicular to the long axis 26 circular, all of the axes of easy rotation other than the long axis 26 can be made into equivalent short axes 25, making it difficult for the object to change center during rotation and facilitating control of the object's rotation. In addition, by making the cross section perpendicular to the long axis 26 of the object according to the present invention circular, it can be easily manufactured using a lathe also known as a potter's wheel, just like the "shaft 2" and "plate body 3" that make up the "shaft 1."

[0046] The shape of the "hole 11" provided in the article according to the present invention is not particularly limited as long as the "tip 7" of the "knock 1" to be used can be easily inserted and the article can be held with the "hole 11" inserted in the "tip 7", and the shape can be appropriately determined according to the length, thickness, etc. of the "tip 7". Since a typical "tip 7" has a circular cross section formed by a potter's wheel, it is generally preferable that the "hole 11" has a length such that the tip of the "tip 7" does not contact the bottom of the "hole 11", and that at least a part of the "hole 11" is cylindrical with a diameter of about 1.2 to 2.5 times the diameter of the "tip 7" to be used, and more preferably, the "hole 11" is cylindrical with a diameter of about 1.2 to 1.4 times the diameter of the "tip 7".

[0047] In particular, from the viewpoint of using the article according to the present invention as a tool to assist in mastering "furiken" or the like, it is also preferable that the shapes of the "hole 11" and "countersink 12" in Fig. 2 and the like are the same as the "hole 11" of the "ball 10" of a general kendama. For example, in a kendama intended for competitive use, the diameter of the "tip 7" is about 10 mm, while the diameter of the "hole 11" provided in the "ball 10" is about 1.2 to 1.4 times that of the "tip 7", and further, the "countersink 12" is formed as a cone surface with an opening angle of about 20 to 40 degrees so that the opening is about 1.5 to 1.6 times the diameter of the "hole 11".

[0048] For this reason, it is preferable that the opening of the "hole portion 11" of the article of the present invention also has a "countersink portion 12" formed by a conical surface having a diameter of about 1.2 to 2.5 times, more preferably about 1.5 to 1.6 times, the diameter of the "hole portion 11", depending on the skill of the user, and an opening angle 17 of about 10 to 70 degrees, more preferably about 20 to 40 degrees.

[0049] In addition, in the present invention, the center line of the "hole 11" refers to the axis indicated by the center line of the "tip 7" when the "tip 7" is inserted into the "hole 11." In particular, when at least a portion of the wall of the "hole 11" is cylindrical, the axis is grasped by the center line of the cylinder. In addition, in this invention, when it is described that the center line of the hole portion and the minor axis 25 of the axis of easy rotation are approximately perpendicular to each other, this means that among the perpendicular lines drawn from the minor axis 25 in the direction of the "hole portion 11," there exists a perpendicular line that can pass through the "hole portion 11" without intersecting the wall surface of the "hole portion 11."

[0050] The article according to the present invention has a thread fastening portion so that the article according to the present invention can be suspended by a thread 9 by fastening an appropriate thread 9. A specific means for fastening a thread to the article according to the present invention can be appropriately selected. For example, a through hole can be opened in the article according to the present invention and a thread can be passed through it, or a member through which a thread can be passed can be attached to the article according to the present invention by an appropriate method. In addition, when the article according to the present invention has a constriction in a part of the article, such as the articles shown in the following Figs. 5 and 6(a), it is also possible to fasten the thread in a form in which the article can rotate on its own axis with the thread 9 fastened by wrapping the thread around the constriction in a circular shape and fastening it.

[0051] The position at which the thread 9 is fastened to the article according to the present invention can be determined appropriately. In particular, the ease of rotation of the article when a driving force is applied by the thread 9 varies depending on the position of the center of gravity of the article according to the present invention and the distance between the thread fastening part for fastening the thread 9, so it is desirable to fasten the thread 9 at a position according to the purpose. The relationship between the position of the thread fastening part for fastening the thread 9 and the ease of rotation of the article can be evaluated mainly by the angle between the thread 9 and the longest axis (long axis 26) among the axes of easy rotation of the article when the article is suspended by the thread 9.

[0052] For example, as in the article shown in Fig. 2, by providing a thread fastening part at the end of the article near the intersection where the longest axis (long axis 26) among the axes of easy rotation of the article intersects with the surface of the article, the moment generated by the driving force applied via the thread 9 becomes large, and the article can be rotated most effectively. In other words, the article can be easily rotated by fastening the thread 9 at a position where the angle between the long axis 26 and the direction of the thread 9 is less than 5 degrees when the article is suspended by the fastened thread and the "hole 11" opens approximately vertically downward.

[0053] On the other hand, by fastening the string 9 at a position closer to the center of gravity of the article, it becomes more difficult to cause the article to rotate on its axis using the driving force applied via the string 9, which is useful for learning the technique of actively controlling the rotation of the flying object in a kendama. Specifically, if the angle between the long axis 26 of the article and the string 9 when the article is suspended by the string 9 is within a range of 5 to 30 degrees, it is possible to cause the article to rotate on its axis using a normal range of movements, and this can be preferably used for learning the technique of controlling the rotation.

[0054] Furthermore, when the angle is in the range of 30 to 70 degrees, active action is required to rotate the article on its axis, and when the angle is in the range of 70 to 90 degrees in particular, it becomes difficult to cause the article to rotate on its axis, and it is preferably used for the purpose of enjoying a new way of playing (a technique) that overcomes difficulties different from those of "furiken" etc. By providing the article according to the present invention with a plurality of thread fastening parts in advance, it is possible to change the position where the thread 9 is fastened as appropriate depending on the purpose of use.

[0055] The article according to the present invention is an article used as a flying object and / or a gripping object in a kendama, and can be made of various materials that make up a kendama. That is, like a general kendama, it can be manufactured from broad-leaved trees such as beech, zelkova, cherry, Itaya maple, and Sophora japonica, by processing it with or without a lathe such as a potter's wheel, using cutting tools such as chisels, planes, and drills.

[0056] Furthermore, when the article according to the present invention is manufactured from plastic or the like, it can be manufactured by molding using a mold of an appropriate shape by general injection molding, etc. In addition, the article according to the present invention can be manufactured by molding using an appropriate material by an appropriate means.

[0057] (3) Regarding the embodiment of the article according to the present invention As explained above, one of the features of the present invention is that the degree of freedom of rotation of an article can be restricted depending on the shape of the article, and by using the article of the present invention mainly as a flying object for a kendama, it becomes easy to control the opening direction of the "hole 11", and helps beginners gradually master tricks such as "furiken". On the other hand, by utilizing the shape of the article of the present invention, it becomes possible to perform tricks that have not been possible before, and provides a new way of playing with kendama.

[0058] Hereinafter, the embodiments of the article according to the present invention will be described by way of examples, but the present invention should not be construed as being limited to each of the embodiments. Another embodiment of the present invention is shown in Fig. 4. Fig. 4 shows an example in which a "hole 11" is formed along the major axis 26 of an ellipsoid, and a "thread hole 13" for fixing a thread is provided at the other end of the "hole 11."

[0059] The object shown in Fig. 4 is an example with intermediate characteristics between a sphere and a cylinder as a flying object, and compared to the cylinder shown in Fig. 2, the inertial force of rotation around the minor axis 25 is smaller and its behavior approaches that of a sphere, making it similar in difficulty to "Furiken" which uses a spherical flying object. When mastering a technique such as "Furiken", first practice catching an object with a large ratio of the major axis / minor axis length as shown in Fig. 2 with the "tip 7" as the flying object, and then use an object with a shape closer to a sphere as the example shown in Fig. 4 as the flying object, and you can gradually master techniques such as "Furiken".

[0060] In addition, due to its surface shape, the object shown in Fig. 4 can be caught by plates 4 to 6 of the "ken 1" by controlling the direction of the "hole 11" when catching it. This technique is more difficult than a typical technique using a large plate, etc., in that it requires control of the rotation of the flying object, and it provides a new technique.

[0061] Fig. 5 shows another embodiment of the present invention. Fig. 5 shows a modified example of the cylinder shown in Fig. 2, in which the ends of the cylinder are made thicker and the center of the cylinder is made thinner to further increase the inertial force of the rotation around the short axis 25, giving the cylinder an overall drum-like shape. In addition, the article shown in Fig. 5 has a plurality of "thread holes 13" at different distances from the center of gravity of the article, and the ease with which the article will rotate when swung as a flying object can be changed in stages, and the article can be preferably used to learn the skill of intentionally rotating an object.

[0062] In addition, in the form shown in Fig. 5, the cylindrical body has "holes 11" facing each other on both ends. A normal kendama "ball 10" has only one "hole 11" and the number of rotations from when it is released until it is caught by the "tip 7" is limited to an integer number of times, whereas in the form shown in Fig. 5, the number of rotations can be set in increments of 1 / 2, which allows the player to learn the skill of generating the above-mentioned rotational motion while providing new techniques. Also, by biasing the portion that is tapered to form a drum shape, it is possible to change the difficulty of catching the ball with the "holes 11" on both ends.

[0063] Furthermore, when using the article in the form shown in Figure 5 as a flying object, the part that is thinned to make it into a drum shape can be used as the string fastening part, and string 9 can be fastened in a ring shape as shown in Figure 5. The string can then be wound around the string fastening part and the article can be swung out, causing it to rotate about long axis 26. In this state, the "tip 7" can be inserted into "hole 11" and the article can be caught. In addition, in FIG. 5, "hole portion 11" is provided independently at each end of the cylinder, but the present invention is not limited to this, and the "hole portion 11" may be provided so as to penetrate the article, thereby making the article have a tubular cross section.

[0064] Figure 6 shows a different embodiment of the present invention. Figure 6(a) corresponds to a "dish body 3" used in a conventional "ken" in which "holes 11" are provided in the large dish 4 and small dish 5 portions. Also, a through hole 16 provided in the center allows attachment to the "ken shaft 2". An article in the form shown in Figure 6(a) can be used preferably for learning control techniques for rotating around a short shaft 25, in the same way as the article shown in Figure 5.

[0065] Also, Fig. 6(b) corresponds to a conventional "kenshaft 2" with a "hole 11" provided in the inner plate 6. The form of Fig. 6(b), like the form shown in Fig. 2, can be preferably used to learn the technique of controlling the rotation of a flying object around its minor axis. Also, compared to the form shown in Fig. 2, the ratio of major axis 26 to minor axis 25 is large, and the center of gravity is significantly biased toward the outer periphery at the time of swinging out, so the rotation speed tends to be slower, and it is preferably used when beginners practice "furiken".

[0066] As shown in Figures 6(a) and (b), the "ken shaft 2" and "dish body 3" that make up the "ken 1" of a conventional kendama have shape anisotropy, and by making "holes 11" at approximately right angles to the minor axis 25 of each easy axis of rotation, an article according to the present invention can be made. Also, in the article shown in Figures 6(a) and (b), by making multiple "string holes 13" and making it possible to change the position of the string fastening part, it becomes possible to change the degree of difficulty of controlling the rotation speed of the spinning motion 22, etc.

[0067] FIG. 7 shows another embodiment of the present invention. FIG. 7(a) corresponds to an article having a general "dish body 3" attached to the article having the form shown in FIG. 6(b). By using the article having the form shown in FIG. 7(a) as the flying object 15, the inertial force related to the rotational motion about the minor axis 25 as the rotation axis becomes larger compared to the form shown in FIG. 6(b), and the rotation speed becomes slower, so that the article is preferably used when practicing the "furiken" motion. In addition, the article having the form shown in FIG. 6(a) can also be used as the "dish body 3" to be attached to the article having the form shown in FIG. 6(b) (FIG. 7(b)).

[0068] Since the "intermediate plate 6" of the "ken 1" and the like are structured to receive the "ball 10" by the ring portion forming the outer periphery of the "plate," the article in the form shown in FIG. 7 can be used as a normal "ken 1" regardless of the presence of the "hole portion 11" provided in each plate portion, and by tying the "ball 10" with the string 9, it is possible to configure a "kendama" as a whole. In other words, the article in the form shown in FIG. 7 can be used mainly as a flying object 15 by tying the "ken 1" with the string 9, and can also be used mainly as a holding object ("ken 1") by tying the "ball 10" to it. Furthermore, by disassembling the article shown in FIG. 7, it is possible to obtain the articles shown in FIG. 6(a) and (b), and it is possible to expand the variety of ways to play with the kendama, not just as a tool for practicing the "furiken" motion.

[0069] Conventional Kendamas are generally sold in the form of a "ken 1" consisting of a "shaft 2" and a "body 3" attached to it, to which a "ball 10" is tied by a string 9, and when a part of the "ken 1" is damaged, it is difficult to use the remaining undamaged parts. In contrast, by forming the "ken 1" part in the form shown in Figures 7(a) and (b), etc., and making the "shaft 2" and "body 3" that make up the "ken 1" usable as flying objects, it becomes possible to utilize the "ken 1" as a tool that provides a new way of playing.

[0070] Furthermore, for example, in the technique called "Airplane," the performer holds "ball 10" so that "hole 11" is visible, and inserts "tip 7" of "ken 1" that has been thrown into "hole 11." When beginners try the "Airplane" technique, there is a problem that the "tip 7" hits the fingers holding "ball 10," causing injury. On the other hand, by holding an item in the form shown in Figure 7 with "middle plate 6" ("hole 11") facing forward, and using another "ken 1" tied with string 9 as a flying object, it becomes possible to safely practice "Airplane."

[0071] In addition, by preparing three or more items of the configuration shown in Figure 7 and tying them together with string 9 in series or branching out, it becomes possible to perform tricks that were not possible with conventional kendama, such as catching a flying object with "ken tip 7" of the flying object caught by "ken 1." [Industrial Applicability]

[0072] The aim is to contribute to the development of related industries by providing items that will help improve kendama skills and by opening up new possibilities for kendama techniques. [Explanation of symbols]

[0073] 1 ken 2. Shaft 3 Plate body 4 Large Plates 5 small plates 6 Medium Plate 7. Tip 8 thread holes 9. Thread 10 balls 11 Hole 12 Counterbore 13 thread hole 14 Beads 15 Projectile 16 Through holes 17 Counterbore opening angle 21 Locomotion 22 Rotation 25 Short axis 26 Long axis

Claims

1. An article having a hole with one or two bottoms into which a kendama tip can be inserted and a string fastening part into which a string can be fastened, the article being used as a flying object and / or a gripping object in a kendama, The article has a specific axis of easy rotation due to its shape anisotropy, and the center lines of the holes in the article are all approximately perpendicular to the axis of easy rotation with the shortest length among the axes of easy rotation, and approximately coincide with the axis of easy rotation with the longest length passing through the article among the axes of easy rotation.

2. The article according to claim 1, characterized in that the ratio obtained by dividing the length of the axis of easy rotation that has the longest length passing through the article by the length of the axis of easy rotation that has the shortest length is 1.1 or more.

3. 3. The article according to claim 1, wherein at least a part of a wall surface constituting the hole is formed into a cylindrical shape centered on a center line of the hole.

4. 4. The article according to claim 1, wherein an opening of the hole is provided with a counterbore.

5. 5. The article according to claim 1, wherein the holes are provided at both ends of the article so as to face each other.

6. An article as described in any one of claims 1 to 4, characterized in that the thread fastening portion is provided at a position where the hole portion opens approximately vertically downward when the article is suspended by a thread fastened to the thread fastening portion.

7. An article as described in any one of claims 1 to 5, characterized in that the thread fastening portion is provided at a position where, when the article is suspended by a thread fastened to the thread fastening portion, the hole portion opens in a direction other than vertically downward.

8. An article as described in any one of claims 1 to 6, characterized in that the article has an overall shaft-like shape, and the hole portion is provided in the dish portion of the shaft.

9. An article as described in any one of claims 1 to 7, characterized in that the article has an overall dish-shaped body, and the hole portion is provided in the dish portion of the dish body.

10. A kendama characterized by including either one or both of the items described in claims 8 and 9.

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