Vibration absorber

Abstract

The present invention provides a vibration absorber that, when attached to a racket, absorbs vibrations caused by the ball's impact and also provides acoustic feedback for the swing. [Solution] The vibration absorber 201 comprises an elastic plate-like portion 210 with an air port 211 formed therein, an elastic plate-like portion 220 with an air port 221 formed therein, and a connecting portion 230 connecting the elastic plate-like portion 210 and the elastic plate-like portion 220. An air passage 240 connecting the air ports 211 and 221 is formed inside the elastic plate-like portions 210, 220 and the connecting portion 230. A resonance chamber 212 extending outward from the air passage 240 is formed inside the elastic plate-like portion 210. This resonance chamber 212 generates a resonant sound due to the air flowing through the air passage 240. The inner diameter of the second air port 221 is larger than the inner diameter of the first air port 211, and the thickness of the elastic plate-like portion 220 is greater than the thickness of the elastic plate-like portion 210.

Description

Technical Field

[0001] The present invention relates to a vibration absorber, and particularly to a vibration absorber that can be attached to the strings of a racket used in tennis or the like.

Background Art

[0002] Conventionally, vibration absorbers that can reduce unpleasant vibrations when a ball hits a racket have been widely used (see, for example, Patent Document 1). By being attached to the strings of a racket, this vibration absorber suppresses the transmission of unpleasant vibrations during ball hitting to the player and contributes to providing comfort to the player. As such vibration absorbers, various shapes, materials, and attachment methods have been proposed conventionally. However, conventional vibration absorbers are specialized in alleviating vibrations, and although they may be used as decorative elements of a racket, there are few that have additional functions other than that.

[0003] On the other hand, in tennis practice, shadow swings are performed for the purpose of checking form and improving swing speed. In such shadow swings, when the racket is swung at a certain speed, a wind cutting sound is generated. There are also not a few players who use such a wind cutting sound as an auditory cue to check their own condition, check their form and swing speed, and help improve the motivation for practice.

[0004] However, in the case of children, the elderly, women, etc. with insufficient arm strength, it is difficult to swing the racket at a sufficient speed, and almost no wind cutting sound is generated. Also, even when the wind cutting sound is generated, the volume is small and it is often difficult to hear over ambient noise. As a result, the motivation for practice may decrease, or they may try to swing the racket forcefully and lose their form, or it may cause pain in the shoulders or the like. Also, for advanced players, it is difficult to feel the improvement of their own swing speed only from the wind cutting sound, and they cannot obtain a sense of achievement during practice, and it is difficult to maintain concentration.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-019519 [Overview of the project] [Problems that the invention aims to solve]

[0006] This invention has been made in view of the problems of the prior art, and aims to provide a vibration absorber that, when attached to a racket, can absorb vibrations caused by hitting the ball and provide acoustic feedback to the swing. [Means for solving the problem]

[0007] According to one aspect of the present invention, a vibration absorber is provided that, when attached to a racket, can absorb vibrations caused by hitting the ball and provide acoustic feedback to the swing. The vibration absorber comprises a first elastic plate-like portion having a first air port having a first inner diameter, a second elastic plate-like portion having a second air port having a second inner diameter larger than the first inner diameter and extending parallel to the first elastic plate-like portion spaced apart from it, and a connecting portion connecting the first elastic plate-like portion and the second elastic plate-like portion. An air passage is formed inside the first elastic plate-like portion, the second elastic plate-like portion, and the connecting portion, connecting the first air port and the second air port. A resonance chamber is formed inside the first elastic plate-like portion, extending outward from the air passage, and this resonance chamber generates a resonant sound due to the air flowing through the air passage. The second elastic plate-like portion has a thickness such that the weight of the first elastic plate-like portion and the weight of the second elastic plate-like portion are balanced. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing a vibration absorber according to a first embodiment of the present invention. [Figure 2] Figure 2 is a front view of the vibration absorber shown in Figure 1. [Figure 3] Figure 3 is a plan view of the vibration absorber shown in Figure 1. [Figure 4] Figure 4 is a bottom view of the vibration absorber shown in Figure 1. [Figure 5] Figure 5 is a cross-sectional view taken along line AA in Figure 3. [Figure 6] Figure 6 is a plan view showing an enlarged view of the recess in the vibration absorber shown in Figure 3. [Figure 7] Figure 7 is a cross-sectional view along line BB in Figure 6. [Figure 8] Figure 8 is a cross-sectional view along the CC line in Figure 6. [Figure 9] Figure 9 is a schematic diagram showing the vibration absorber shown in Figure 1 attached to the racket. [Figure 10] Figure 10 is a cross-sectional view showing a modified example of the vibration absorber shown in Figure 1. [Figure 11] Figure 11 is a perspective view showing a vibration absorber in a second embodiment of the present invention. [Figure 12] Figure 12 is a front view of the vibration absorber shown in Figure 11. [Figure 13] Figure 13 is a plan view of the vibration absorber shown in Figure 11. [Figure 14] Figure 14 is a bottom view of the vibration absorber shown in Figure 11. [Figure 15] Figure 15 is a cross-sectional view of the DD line in Figure 13. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the vibration absorber according to the present invention will be described in detail with reference to Figures 1 to 15. In Figures 1 to 15, identical or corresponding components are denoted by the same reference numerals, and redundant explanations are omitted. In addition, in Figures 1 to 15, the scale and dimensions of each component may be exaggerated, or some components may be omitted.

[0010] In the following description and claims, unless otherwise specified, terms such as “first” and “second” are used solely to distinguish components from one another and do not represent any particular order or sequence. Furthermore, when referring to something as “equal to” a specific number, unless otherwise specified, it means being within the range of 90% to 110% of that number.

[0011] Figure 1 is a perspective view showing a vibration absorber 1 in one embodiment of the present invention, Figure 2 is a front view, Figure 3 is a top view, Figure 4 is a bottom view, and Figure 5 is a cross-sectional view taken along line AA in Figure 3. As shown in Figures 1 to 5, the vibration absorber 1 includes an elastic plate-like portion 10 (first elastic plate-like portion) having an air vent 11 (first air vent) formed in the center, an elastic plate-like portion 20 (second elastic plate-like portion) having an air vent 21 (second air vent) formed in the center, and a cylindrical connecting portion 30 connecting the elastic plate-like portion 10 and the elastic plate-like portion 20.

[0012] The elastic plate-like parts 10 and 20 are spaced apart from each other in the Z direction and both extend parallel to each other along the XY plane. The gap between the elastic plate-like parts 10 and 20 is smaller than the outer diameter of the strings stretched on the racket, and the distance between the elastic plate-like parts 10 and 20 is, for example, 1.0 mm. The outer diameter of the connecting part 30 is slightly larger than the distance between adjacent strings, for example, 10.0 mm. The thickness of the elastic plate-like part 10 is, for example, 5.0 mm, and the thickness of the elastic plate-like part 20 is, for example, 3.5 mm. The reason why the thicknesses of the elastic plate-like parts 10 and 20 are different is to compensate for the weight balance caused by the structural differences between these elastic plate-like parts 10 and 20.

[0013] In this embodiment, the elastic plate-like portion 10 has an outer edge 10A whose distance from the center of the air vent 11 varies along the circumferential direction, and similarly, the elastic plate-like portion 20 has an outer edge 20A whose distance from the center of the air vent 21 varies along the circumferential direction. In this embodiment, the distance from the air vents 11 and 21 to the outer edges 10A and 20A is 13.0 mm at its longest point and 11.25 mm at its shortest point, forming roughly star-shaped outer edges 10A and 20A.

[0014] As shown in FIG. 5, an air flow path 40 that connects the air port 11 and the air port 21 is formed inside the elastic plate-like portions 10 and 20 and the connecting portion 30. The air ports 11 and 21 and the air flow path 40 extend perpendicularly to the surface 10B of the elastic plate-like portion 10 and the surface 2OB of the elastic plate-like portion 20, and are arranged side by side on the same line extending in the Z direction.

[0015] As shown in FIG. 5, a resonance chamber 12 that expands outward from the air flow path 40 is formed inside the elastic plate-like portion 10. This resonance chamber 12 is for generating a resonance sound by the air flowing through the air flow path 40. For example, the diameter of the resonance chamber 12 is 20.0 mm. This resonance chamber 12 is configured to easily cause a pressure change efficiently even with a small volume, and to stabilize the generation of the resonance sound.

[0016] As shown by the arrow in FIG. 5, air flows from the air port 11 through the resonance chamber 12 and the air flow path 40 to the air port 21, and also air flows from the air port 21 through the air flow path 40 and the resonance chamber 12 to the air port 11. The inflow direction of the air changes according to the swing direction of the racket, and a resonance sound is generated when the air passing through the resonance chamber 12 reaches a flow velocity of a certain level or more. This is because in the resonance chamber 12, when the air passing through the air flow path 40 flows along the inner wall of the resonance chamber 12, when the flow velocity exceeds the threshold value, periodic vortices (Karman vortices) are formed in the direction perpendicular to the air flow, and these vortices induce pressure fluctuations in the resonance chamber 12 and propagate as air vibrations.

[0017] A tapered surface 13 is formed on the side of the resonant chamber 12 facing the air inlet 11, and the diameter of the airflow channel 40 gradually decreases from the air inlet 11 toward the resonant chamber 12. Similarly, a tapered surface 14 is formed on the opposite side of the resonant chamber 12 from the tapered surface 13, and the diameter of the airflow channel 40 also gradually decreases toward the resonant chamber 12. These tapered surfaces 13 and 14 accelerate the flow velocity of the air passing through the airflow channel 40, stabilizing the generation of Karman vortices, and thus efficiently generating acoustic vibrations within the resonant chamber 12. Furthermore, by adjusting the angles of the tapered surfaces 13 and 14, the flow velocity (resonance sensitivity) required for the generation of resonant sound can be arbitrarily set.

[0018] As shown in Figure 3, the elastic plate-like portion 10 has a plurality of recesses 15 (first recesses) that extend radially around the air vent 11. In this embodiment, the elastic plate-like portion 10 has eight recesses 15, but the number of recesses 15 is not limited to this. It is preferable that these recesses 15 are arranged at equal angular intervals with respect to the air vent 11.

[0019] Figure 6 is a plan view showing an enlarged view of the recess 15, Figure 7 is a cross-sectional view of Figure 6 along line BB, and Figure 8 is a cross-sectional view of Figure 6 along line CC. The radial length of the recess 15 is preferably 7.5 mm, which corresponds to approximately 50% to approximately 65% ​​of the distance from the center of the elastic plate-like portion 10 to the outer edge 10A, and also preferably occupies approximately 70% to approximately 80% of the surface 10B of the elastic plate-like portion 10 located radially outside the air vent 11.

[0020] As shown in Figure 6, the recess 15 has an outer end 15A located radially outward and an inner end 15B located radially inward. For example, the outer end 15A has a spherical inner surface with a diameter of 2.0 mm, and the inner end 15B has a spherical inner surface with a diameter of 1.0 mm. As shown in Figure 6, the width of the recess 15 along the circumferential direction narrows towards the air vent 11 (located on the left side in Figure 6), that is, towards the radially inward direction. For example, the width of the inner end 15B of the recess 15 is preferably about 0.25 to about 0.75 times the width of the outer end 15A, more preferably about 0.4 to about 0.6 times, and even more preferably about 0.5 times.

[0021] Furthermore, as shown in Figure 7, the depth of the recess 15 increases towards the air vent 11 (located on the left side in Figure 7), that is, towards the radially inward direction. For example, the inclination angle of the bottom surface 17 of the recess 15 is preferably about 6 degrees to about 10 degrees, and more preferably about 8 degrees. For example, the depth of the inner end 15B of the recess 15 is preferably about 2.0 to about 3.5 times the depth of the outer end 15A, more preferably about 2.5 to about 3.0 times, and even more preferably about 2.75 times.

[0022] Furthermore, as shown in Figure 8, the circumferential side surface 16 of the recess 15 is a tapered surface that widens outward from the bottom surface 17, and the recess 15 has an inverted trapezoidal cross-section. For example, the taper angle of the side surface 16 of the recess 15 is preferably about 15 degrees to about 25 degrees, and more preferably about 20 degrees.

[0023] As shown in Figure 4, the elastic plate-like portion 20 has a plurality of recesses 25 (second recesses) that extend radially around the air vent 21. Since the position and structure of these recesses 25 are symmetrical with respect to the recess 15 with respect to the XY plane, a detailed explanation of the recesses 25 is omitted.

[0024] Figure 9 is a schematic diagram showing the vibration absorber 1 attached to the strings 6 of a racket 5 (for example, a tennis racket). As described above, the gap between the elastic plate-like portion 10 and the elastic plate-like portion 20 is smaller than the outer diameter of the strings 6 stretched on the racket 5, and the outer diameter of the connecting portion 30 is slightly larger than the distance between adjacent strings 6. Therefore, by sandwiching the strings 6 between the elastic plate-like portion 10 and the elastic plate-like portion 20 of the vibration absorber 1, the vibration absorber 1 can be attached to the strings 6 as shown in Figure 9. In this state, the connecting portion 30 of the vibration absorber 1 is firmly held between the two vertically extending strings 6, and the elastic plate-like portion 10 and the elastic plate-like portion 20 maintain a state of close contact with the strings 6. This improves the vibration absorption efficiency of the vibration absorber 1.

[0025] Recesses 15 and 25 are formed on the surfaces of the elastic plate-like parts 10 and 20 to promote the generation of turbulence. These recesses 15 and 25 intentionally create turbulence in the airflow, and this turbulence promotes the formation of negative pressure near the inlet hole, increasing the efficiency of air inflow. At the same time, it helps diffuse the air during outflow, stabilizing the pressure changes in the resonance chamber and improving the air discharge effect, making the generation of resonant sound more stable and clearer. As a result, when a racket 5 with the vibration absorber 1 attached to the strings 6 is swung, the airflow generated around the vibration absorber 1 efficiently flows directly into the resonance chamber 12 from the air outlet 11, and also flows stably into the resonance chamber 12 through the air passage 40 from the other air outlet 21, promoting the generation of resonant sound within the resonance chamber 12.

[0026] In this way, when the racket 5 with the vibration absorber 1 attached to the strings 6 is swung, a resonant sound is generated in the resonance chamber 12. Therefore, even during practice swings without hitting a ball, the user can auditorily grasp the speed and angle of the swing, which can be used to check form and to encourage increased speed. In addition, since a clear resonant sound can be generated even at relatively low swing speeds, this vibration absorber 1 can contribute to improving the motivation of practice and safely acquiring proper form for people with less arm strength, such as children and the elderly.

[0027] Furthermore, since air flows into the resonance chamber 12 from both air vents 11 and 21, resonant sound can be stably generated regardless of which side of the racket 5 is facing the swing direction. Through this airflow behavior and structural design, the user can intuitively and comfortably obtain acoustic feedback without having to be conscious of the front or back of the racket 5.

[0028] Furthermore, the resonant sound generated during this swing is sufficiently clear to the user, yet not excessively loud or irritating in tone. Therefore, the vibration absorber 1 can be used comfortably without interfering with play, even in situations requiring consideration for others, such as during actual practice. Thus, the vibration absorber 1 in this embodiment is a next-generation practice support device that not only absorbs vibrations but also has an educational function that supports form acquisition through auditory feedback.

[0029] Even at relatively low swing speeds, the recesses 15 and 25 formed on the surfaces of the elastic plate-like parts 10 and 20 create fine turbulence in the airflow, allowing air to flow into the resonance chamber 12 from either the air vent 11 or 21 and out from the other air vent 21 or 11, thereby generating a resonant sound. Furthermore, as the swing speed increases, the recesses 15 or 25 create stronger turbulence on the back side of the racket 5, forming a localized negative pressure region. Air then flows into the resonance chamber 12 from either the air vent 11 or 21 on the back side and out from the other air vent 21 or 11, resulting in a stable acoustic effect. Therefore, a stable acoustic effect can be obtained regardless of which side of the racket 5 is facing the direction of the swing.

[0030] Thus, although the behavior of the airflow changes depending on the swing speed and the orientation of the racket 5, a stable resonant sound is always obtained due to the structure of the vibration absorber 1 described above.

[0031] The vibration absorber 1 is preferably integrally formed from an elastomer material that possesses flexibility and durability. By forming the vibration absorber 1 from such an elastic material, it is possible to effectively absorb vibrations during ball impact while possessing the shape retention and flexibility necessary for generating resonant sound. In particular, by integrally forming the vibration absorber 1 from silicone rubber with a Shore A hardness of about 40, appropriate flexibility and resilience can be ensured, achieving both vibration absorption during ball impact and generation of resonant sound.

[0032] Furthermore, the vibration absorber 1 can adjust the likelihood of generating resonant sounds depending on its mounting position. For example, when practicing with hitting balls in addition to swing practice, attaching the vibration absorber 1 near the center on the side closer to the grip 7 (vibration absorber 1A in Figure 9) makes it possible to obtain acoustic feedback while minimizing the impact on play. On the other hand, when children or elderly people with less arm strength practice swing practice without hitting balls, attaching it near the center on the side closer to the head 8 (vibration absorber 1B in Figure 9) increases the speed of movement during the swing, making it easier to obtain clear sounds and enhancing the enjoyment and sense of accomplishment of practice.

[0033] Furthermore, a larger taper angle on tapered surfaces 13 and 14 reduces the resonance sensitivity to airflow velocity. By adjusting the taper angle of tapered surfaces 13 and 14, the swing speed required to generate resonance can be adjusted. For example, setting the taper angle of tapered surfaces 13 and 14 to a gentle 30 degrees creates a configuration suitable for beginners (basic model) that easily generates resonance. For example, setting the taper angle of tapered surfaces 13 and 14 to around 35 degrees creates a standard configuration (advanced model), while setting the taper angle of tapered surfaces 13 and 14 to a steep 45 degrees creates a configuration suitable for advanced users that makes it difficult to generate resonance (professional model). By adjusting the taper angle of tapered surfaces 13 and 14 in this way, it is possible to make it difficult to generate resonance unless the swing speed is above a certain level, thus creating a configuration suitable for advanced users to increase their motivation to improve their skills.

[0034] By structurally adjusting the tapered surfaces 13 and 14 in this way, it becomes possible to select the conditions for generating resonant sound according to the user's skill level and purpose, contributing to improved practice efficiency and a sense of accomplishment. Furthermore, since the user can obtain acoustic feedback according to their swing speed and form through the vibration absorber 1, the vibration absorber 1 can be used as a tool to support gradual skill acquisition.

[0035] In the embodiment described above, recesses 15 and 25 are formed in the elastic plate-like portions 10 and 20. However, instead of the recesses 15 and 25, annular protrusions 115 (first protrusion) and 125 (second protrusion) may be formed around the air vents 11 and 21 of the elastic plate-like portions 10 and 20, respectively, as shown in Figure 10.

[0036] Figure 11 is a perspective view showing the vibration absorber 201 in a second embodiment of the present invention, Figure 12 is a front view, Figure 13 is a plan view, Figure 14 is a bottom view, and Figure 15 is a cross-sectional view along the DD line of Figure 13. As shown in Figures 11 to 15, the vibration absorber 201 includes a disc-shaped elastic plate portion 210 (first elastic plate portion) with an air vent 211 (first air vent) formed in the center, a disc-shaped elastic plate portion 220 (second elastic plate portion) with an air vent 221 (second air vent) formed in the center, and a cylindrical connecting portion 230 connecting the elastic plate portion 210 and the elastic plate portion 220.

[0037] In this embodiment, the outer diameter of the elastic plate-like portion 210 and the elastic plate-like portion 220 are equal, for example, 25.0 mm in diameter. The elastic plate-like portion 210 and the elastic plate-like portion 220 are spaced apart from each other in the Z direction and both extend parallel to each other along the XY plane. The gap between the elastic plate-like portion 210 and the elastic plate-like portion 220 is smaller than the outer diameter of the strings stretched on the racket, and the distance between the elastic plate-like portion 210 and the elastic plate-like portion 220 is for example 1.0 mm. The outer diameter of the connecting portion 230 is slightly larger than the distance between adjacent strings, for example 11.0 mm. The thickness of the elastic plate-like portion 210 is for example 6.5 mm, and the thickness of the elastic plate-like portion 220 is for example 3.5 mm. The reason why the thicknesses of the elastic plate-like portion 210 and the elastic plate-like portion 220 are different is to compensate for the weight balance caused by the structural differences between these elastic plate-like portions 210 and 220.

[0038] As shown in Figure 15, an air passage 240 connecting air ports 211 and 221 is formed inside the elastic plate-like portions 210, 220 and the connecting portion 230. The air ports 211, 221 and the air passage 240 extend perpendicularly to the surface 210B of the elastic plate-like portion 210 and the surface 220B of the elastic plate-like portion 220, and are arranged side by side on the same line extending in the Z direction.

[0039] As shown in Figure 15, a resonance chamber 212 extending outward from the air passage 240 is formed inside the elastic plate-like portion 210. This resonance chamber 212 is designed to generate resonant sound using the air flowing through the air passage 240. For example, the diameter of the resonance chamber 212 is 23.0 mm. This resonance chamber 212 is configured to efficiently generate pressure changes even with a small volume, ensuring stable generation of resonant sound.

[0040] As shown by the arrows in Figure 15, air flows from the air inlet 211 through the resonant chamber 212 and the air passage 240 to the air inlet 221, and also flows from the air inlet 221 through the air passage 240 and the resonant chamber 212 to the air inlet 211. The direction of air inflow changes according to the swing direction of the racket, and a resonant sound is generated when the air passing through the resonant chamber 212 reaches a certain flow velocity. This is because, in the resonant chamber 212, when the air that has passed through the air passage 240 flows along the inner wall of the resonant chamber 212, a periodic vortex (Karman vortex) is formed perpendicular to the airflow when the flow velocity exceeds a threshold, and this vortex induces pressure fluctuations within the resonant chamber 212, which propagate as air vibrations.

[0041] The linear arrangement of the air inlet 211, air passage 240, and air inlet 221 described above allows for smooth airflow through the air passage 240, resulting in efficient pressure changes in the resonance chamber 212. This improves the responsiveness of the resonance chamber 212, making it possible to generate resonant sound stably.

[0042] An annular protrusion 215 (first protrusion) is integrally formed around the air vent 211 of the elastic plate-like portion 210. Similarly, an annular protrusion 225 (second protrusion) is integrally formed around the air vent 221 of the elastic plate-like portion 220. These protrusions 215 and 225 play a role in intentionally creating turbulence in the airflow near the surfaces 210B and 220B of each elastic plate-like portion 210 and 220 when the racket is swung at an angle nearly perpendicular to the ground, thereby promoting the formation of negative pressure near the air vents 211 and 221.

[0043] In this embodiment, the inner diameter of the first air port 211 (first inner diameter) is, for example, 5.0 mm, and the inner diameter of the second air port 221 (second inner diameter) is, for example, 6.0 mm, with the second air port 221 being larger than the first air port 211. Since the air port 221 is further away from the resonance chamber 212 than the air port 211, and the length of the air passage 240 is greater, the resistance to the flow of air flowing in from the air port 221 is relatively increased. In order to compensate for this resistance difference and equalize the flow velocity of the air flowing into the resonance chamber 212 from both sides, it is effective to configure the air port 221 to have a larger diameter than the air port 211. As a result, regardless of whether the front or back side of the racket is facing the swing direction, the resonance conditions in the resonance chamber 212 are stable, and a clear resonant sound can be obtained.

[0044] A tapered surface 213 is formed on the side of the resonant chamber 212 facing the air inlet 211, and the diameter of the air passage 240 gradually decreases from the air inlet 211 toward the resonant chamber 212. Similarly, a tapered surface 214 is formed on the opposite side of the resonant chamber 212 from the tapered surface 213, and the diameter of the air passage 240 gradually decreases toward the resonant chamber 212. In this embodiment, the minimum inner diameter of the tapered surface 213 is 4.0 mm, and the minimum inner diameter of the tapered surface 214 is 4.0 mm. These tapered surfaces 213 and 214 accelerate the flow velocity of the air passing through the air passage 240, stabilizing the generation of Karman vortices, and thus efficiently generating acoustic vibrations within the resonant chamber 212. Furthermore, by adjusting the angles of the tapered surfaces 213 and 214, the flow velocity (resonance sensitivity) required to generate resonant sound can be arbitrarily set.

[0045] Furthermore, the combination of these tapered surfaces 213, 214 and the large-diameter air port 221 described above appropriately compensates for the difference in airflow resistance, resulting in efficient and stable pressure fluctuations in the resonance chamber 212. As a result, the generation of resonant sound becomes even more reliable, and the user can obtain clear acoustic feedback corresponding to their swing speed and form.

[0046] As described above, the gap between the elastic plate-like portion 210 and the elastic plate-like portion 220 is smaller than the outer diameter of the string 6 stretched on the racket 5, and the outer diameter of the connecting portion 230 is slightly larger than the distance between adjacent strings 6 (see Figure 9). Therefore, the vibration absorber 201 can be attached to the string 6 by sandwiching the string 6 between the elastic plate-like portion 210 and the elastic plate-like portion 220 of the vibration absorber 201. In this state, the connecting portion 230 of the vibration absorber 201 is firmly held between the two vertically extending strings 6, and the elastic plate-like portion 210 and the elastic plate-like portion 220 maintain a state of close contact with the string 6. This improves the vibration absorption efficiency of the vibration absorber 201.

[0047] In this way, when a racket with the vibration absorber 201 attached to the strings is swung, a resonant sound is generated in the resonance chamber 212. Therefore, even during practice swings without hitting a ball, the user can auditorily grasp the speed and angle of the swing, which can be used to check form and to encourage increased speed. In addition, since a clear resonant sound can be generated even at relatively low swing speeds, this vibration absorber 201 can contribute to improving the motivation of practice and safely acquiring proper form for people with less arm strength, such as children and the elderly.

[0048] Furthermore, since air flows into the resonance chamber 212 from both air inlets 211 and 221, resonant sound can be stably generated regardless of which side of the racket is facing the swing direction. Through this airflow behavior and structural design, the user can intuitively and comfortably obtain acoustic feedback without having to be conscious of the front or back of the racket.

[0049] Furthermore, the resonant sound generated during this swing is sufficiently clear to the user, yet not excessively loud or irritating in tone. Therefore, the vibration absorber 201 can be used comfortably without interfering with play, even in situations requiring consideration for others or during actual practice sessions. Thus, the vibration absorber 201 in this embodiment is a next-generation practice support device that not only absorbs vibrations but also possesses an educational function that supports form acquisition through auditory feedback.

[0050] The vibration absorber 201 is preferably integrally formed from an elastomer material that possesses flexibility and durability. By forming the vibration absorber 201 from such an elastic material, it is possible to effectively absorb vibrations during ball impact while also possessing the shape retention and flexibility necessary for generating resonant sound. In particular, by integrally forming the vibration absorber 201 from silicone rubber with a Shore A hardness of about 40, appropriate flexibility and resilience can be ensured, achieving both vibration absorption during ball impact and generation of resonant sound.

[0051] As described above, a resonance chamber 212 is formed inside the elastic plate-like portion 210. Therefore, the elastic plate-like portion 210 and the elastic plate-like portion 220 are structurally different, and it is conceivable that the weight balance between the elastic plate-like portion 210 and the elastic plate-like portion 220 will be disrupted. Accordingly, in this embodiment, the thickness of the elastic plate-like portion 220 is adjusted so that the weight of the elastic plate-like portion 210 and the weight of the elastic plate-like portion 220 are balanced.

[0052] Furthermore, the vibration absorber 201 can adjust the likelihood of generating resonant sounds depending on its mounting position. For example, when practicing with hitting balls in addition to swing practice, attaching the vibration absorber 201 near the center of the grip side makes it possible to obtain acoustic feedback while minimizing the impact on play. On the other hand, when children or elderly people with less arm strength practice swings without hitting balls, attaching it near the center of the head side increases the speed of movement during the swing, making it easier to obtain clear sounds and enhancing the enjoyment and sense of accomplishment of practice.

[0053] Furthermore, a larger taper angle on tapered surfaces 213 and 214 reduces the resonance sensitivity to airflow velocity. By adjusting the taper angle of tapered surfaces 213 and 214, the swing speed required to generate resonance can be adjusted. For example, setting the taper angle of tapered surfaces 213 and 214 to a gentle 30 degrees creates a configuration suitable for beginners, where resonance is easily generated (basic model). For example, setting the taper angle of tapered surfaces 213 and 214 to around 35 degrees creates a standard configuration (advanced model), while setting the taper angle of tapered surfaces 213 and 214 to a steep 45 degrees creates a configuration suitable for advanced users, where resonance is less likely to be generated (professional model). By adjusting the taper angle of tapered surfaces 213 and 214 in this way, it is possible to make it difficult for resonance to be generated unless the swing speed is above a certain level, thus creating a configuration suitable for advanced users to increase their motivation to improve their skills.

[0054] By structurally adjusting the tapered surfaces 213 and 214 in this way, it becomes possible to select the conditions for generating resonant sound according to the user's skill level and purpose, contributing to improved practice efficiency and a sense of accomplishment. Furthermore, since the user can obtain acoustic feedback according to their swing speed and form through the vibration absorber 201, the vibration absorber 201 can be used as a tool to support gradual skill acquisition.

[0055] The dimensions, shape, and arrangement of the air inlet 211, the resonance chamber 212, the air passage 240, and the air inlet 221 can be appropriately changed according to the desired resonance frequency and volume.

[0056] As described above, the vibration absorber according to the present invention can employ the following configuration. [Configuration 1] A first elastic plate-like portion having a first inner diameter and a first air vent formed therein, A second air vent is formed having a second inner diameter larger than the first inner diameter, and the second elastic plate-like portion extends parallel to the first elastic plate-like portion, spaced apart from the first elastic plate-like portion. A connecting portion that connects the first elastic plate-like portion and the second elastic plate-like portion. Equipped with, An air passage is formed inside the first elastic plate-like portion, the second elastic plate-like portion, and the connecting portion, connecting the first air port and the second air port. Inside the first elastic plate-like portion described above, a resonance chamber is formed that extends outward from the air passage, and generates resonant sound by the air flowing through the air passage. The second elastic plate-like portion has a thickness such that the weight of the first elastic plate-like portion and the weight of the second elastic plate-like portion are balanced. Vibration absorber.

[0057] [Configuration 2] The vibration absorber according to configuration 1, wherein the first air inlet, the second air inlet, and the air passage are aligned on the same line.

[0058] [Configuration 3] A vibration absorber according to configuration 1 or 2, wherein tapered surfaces are formed on the first air inlet side and the second air inlet side, respectively, with the above-mentioned resonance chamber in between.

[0059] [Structure 4] The first elastic plate-like portion has a first convex portion that extends in an annular shape around the first air vent, The second elastic plate-like portion has a second protrusion that extends in an annular shape around the second air vent. A vibration absorber as described in any of configurations 1 to 3.

[0060] Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the embodiments described above and may be implemented in various different forms within the scope of its technical concept. [Explanation of Symbols]

[0061] 1,201 Vibration absorber 5 rackets 6 strings 7 Grip 8 heads 10,210 Elastic plate-like portion (first elastic plate-like portion) 10A Outer edge 11,211 Air vent (First air vent) 12,212 resonance chamber 13, 14, 213, 214 Tapered surface 15. Recess (First recess) 20,220 Elastic plate-like portion (second elastic plate-like portion) 20A outer edge 21,221 Air vent (second air vent) 25. Recess (Second recess) 30,230 connection part 40,240 air passages 115,215 Convex part (First convex part) 125,225 Convex part (second convex part)

Claims

1. A first elastic plate-like portion having a first inner diameter and a first air vent formed therein, A second air vent is formed having a second inner diameter larger than the first inner diameter, and the second elastic plate-like portion extends parallel to the first elastic plate-like portion, spaced apart from the first elastic plate-like portion. A connecting portion that connects the first elastic plate-like portion and the second elastic plate-like portion. Equipped with, An air passage is formed inside the first elastic plate-like portion, the second elastic plate-like portion, and the connecting portion, connecting the first air port and the second air port. Inside the first elastic plate-like portion, a resonance chamber is formed that extends outward from the air passage, and generates a resonant sound by the air flowing through the air passage. The second elastic plate-like portion has a thickness such that the weight of the first elastic plate-like portion and the weight of the second elastic plate-like portion are balanced. Vibration absorber.

2. The vibration absorber according to claim 1, wherein the first air port, the second air port, and the air passage are aligned on the same line.

3. The vibration absorber according to claim 1, wherein tapered surfaces are formed on the first air inlet side and the second air inlet side, respectively, with respect to the resonance chamber.

4. The first elastic plate-like portion has a first convex portion that extends in an annular shape around the first air vent, The second elastic plate-like portion has a second convex portion that extends in an annular shape around the second air vent. A vibration absorber according to any one of claims 1 to 3.

Images