EP3785771A1

EP3785771A1 - Badminton racket

Info

Publication number: EP3785771A1
Application number: EP19793536.4A
Authority: EP
Inventors: Kazuya Otani; Akinori Sano
Original assignee: Yonex KK
Current assignee: Yonex KK
Priority date: 2018-04-27
Filing date: 2019-04-17
Publication date: 2021-03-03
Anticipated expiration: 2039-04-17
Also published as: CN112041037B; JP7085399B2; DK3785771T3; WO2019208344A1; EP3785771B1; CN112041037A; EP3785771A4; JP2019187956A

Abstract

To enhance a degree of freedom in adjusting a weight and a balance point. A racket (10) according to the present invention includes: a frame (13) extending in an annular shape; a grip (11); and a shaft (12) which extends and connects the grip and the frame each other. The shaft is formed to have hollow regions (23, 24) in a shaft body (22) except for a coupling portion, at which the shaft is coupled to the frame, and to have a solid region (25) which is arranged with the at least one hollow region in an extending direction. It is possible to adjust the weight and the balance point of the entire racket by changing the lengths and the positions of the solid region and the hollow regions in the extending direction of the shaft body.

Description

Technical Field

The present invention relates to a badminton racket provided with a shaft.

Background Art

Badminton is played by players swinging rackets and hitting a shuttlecock. As disclosed in Patent Literature 1, for example, a badminton racket is constituted by a grip, an annular frame and a shaft which linearly extends and connects the grip and the annular frame each other.
In order for a badminton racket to exhibit its performance (control performance and resilience performance), importance is placed on adjustment of a dimension (balance point) from a grip end to a center of gravity in addition to the total weight. Therefore, racket manufacturers are required to prepare a lineup of rackets with various weights and balance points in accordance with each player's skill levels, playing styles, preferences, and so on.
According to Patent Literature 1, the sectional shape and the dimension of the frame are altered in order to vary the weight and the balance point of the badminton racket.

Citation List

Patent Literature

Patent Literature 1: Japanese Unexamined Patent Publication No. 6-71001

Summary of Invention

Technical Problem

It is desirable that the weight and the balance point of the badminton racket be adjustable at a location that does not affect the shape and the sectional structure of the frame to further enhance a degree of freedom in the adjustment.
The present invention was made in view of the aforementioned circumstances, and an object thereof is to provide a badminton racket capable of enhancing a degree of freedom in adjusting a weight and a balance point.

Solution to Problem

A badminton racket according to the present invention includes: a frame extending in an annular shape; a grip; and a shaft which extends and connects the grip and the frame each other, and the shaft is formed to have at least one hollow region in a shaft body except for a coupling portion, at which the shaft is coupled to the frame, and to have at least one solid region which is arranged with the at least one hollow region in an extending direction.
With this configuration, since the solid region and the hollow regions are formed in the shaft body, it is possible to adjust the weight and the balance point of the entire racket by changing the length and the position of each of the regions in the extending direction of the shaft body. Thus, it is possible to adjust the weight and the balance point without changing structures of the frame and the grip or along with changes in such structures and thereby to enhance a degree of freedom in the adjustment.
In the present invention, the hollow region is preferably formed in a region in which the shaft body is embedded in the grip. With this configuration, it is possible to reduce the weight of the region of the shaft body embedded in the grip with a relatively low requirement for strength. Also, by taking advantage of that reduced weight to form the solid region at a portion near the frame makes it possible to locate the balance point close to a top end of the racket.
In the present invention, the at least one solid region is preferably formed in a region which includes a kick point in deflection of the shaft body. With this configuration, it is possible to suppress deflection of the shaft at the time of hitting a shuttlecock and to enhance control performance by locating the kick point in the solid region. Also, it is possible to maintain bending rigidity even if a diameter of the shaft is reduced. Consequently, it is possible to maintain resilience performance for hitting the shuttlecock, and to enhance swing-through performance through reduction of air resistance at the time of swinging as a result of the decrease in diameter.
In the present invention, the hollow regions are preferably formed on opposite sides of the shaft body in an extending direction. With this configuration, it is possible to set the position of the center of gravity of the shaft itself at the center in the extending direction.

Advantageous Effect of Invention

According to the present invention, the solid region and the hollow regions are formed in the shaft body, and it is thus possible to enhance a degree of freedom in adjusting the weight and the balance point.

Brief Description of Drawings

[Figure 1] Figure 1 is a front view of a racket according to an embodiment of the present invention.
[Figure 2] Figure 2A is a sectional view illustrating an example of a shaft taken along the line A-A in Figure 1, and Figure 2B is a sectional view illustrating another example of the shaft.

Description of Embodiment

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. Figure 1 is a front view of a badminton racket according to the embodiment. Note that a part of the configuration may be omitted for convenience of explanation in each of the drawings described below.
As illustrated in Figure 1, a badminton racket (hereinafter, referred to as a "racket") 10 includes a grip 11 to be held by a player, a shaft 12 extending in a linear direction with one end side thereof coupled to the grip 11, and a frame 13 with an oval annular shape coupled to the other end side of the shaft 12. A string 14 is extended in a tensioned state inside the frame 13, and the string 14 forms a hitting surface 15 to hit a shuttlecock.
Note that in the description of the claims and the specification, the side on which the frame 13 is positioned in the longitudinal direction of the racket 10 will be defined as a top end side while the side on which the grip 11 is positioned will be defined as a rear end side as illustrated by the arrow in Figure 1 unless otherwise particularly indicated. Also, the direction that is orthogonal to the hitting surface 15 will be defined as a forward/backward direction, and further, the direction that is orthogonal to the longitudinal direction on the hitting surface 15 (that is, on the plane along the hitting surface 15) will be defined as a left-right direction.
The grip 11 and the shaft 12 are coupled to each other in a state in which the shaft 12 is inserted (embedded) into the grip 11 by a predetermined length and is secured thereto with an adhesive or the like.
The frame 13 is constituted by a hollow member having a predetermined wall thickness, and it is possible to employ various shapes such as a circular shape, an oval shape, and a square shape as a sectional shape thereof. The frame 13 is formed using inner pressure shaping based on expansion of a medium such as air. Although it is possible to exemplify a method of forming the frame 13 by filling the inside thereof with a predetermined foaming material, the filling with the foaming material may be omitted at a part or an entirety of the frame 13. The frame 13 and the shaft 12 are coupled to each other with a T-shaped joint 16 built therein in the racket 10.
Figure 2A is a sectional view illustrating an example of the shaft taken along the line A-A in Figure 1. As illustrated in Figure 2A, the shaft 12 is configured of a coupling portion 21, into which a part of the joint 16 is inserted, at which the shaft 12 is coupled to the frame 13 (see Figure 1), and a shaft body 22 that forms a region except for the coupling portion 21. In the shaft body 22, hollow regions 23 and 24 are formed in opposite portions in the extending direction thereof, and a solid region 25 is formed in extending direction, between the hollow regions 23 and 24, in such a manner that where the solid region 25 is provided covers the center of the shaft body 22 in the extending direction.
The lengths and the positions of the hollow regions 23 and 24 and the solid region 25 in the extending direction of the shaft body 22 can be changed in various manners, and Figure 2A illustrates one of the examples. In Figure 2A, the hollow region 23 on the side of the grip 11 is formed in a region in which the shaft body 22 is embedded in the grip 11.
Incidentally, the shaft 12 causes deflection when the racket 10 hits the shuttlecock. The position at which the shaft 12 causes the maximum deflection when the deformation occurs is defined as a kick point KP, and it is possible to hit back the shuttlecock by locally deflecting the shaft 12 at such a position. In Figure 2A, the solid region 25 is formed in a region which includes the kick point KP.
It is possible to exemplify formation of the shaft 12 mainly using a thermosetting fiber-reinforced plastic (fiber reinforced plastics; FRP). Note that the fiber-reinforced plastic is obtained by blending reinforcement fiber in a thermosetting resin such as epoxy or vinyl ester resin and semi-hardening the blended substances, and that the reinforcement fiber can be selected from among carbon fiber, glass fiber, organic fiber, ceramic fiber, and the like.
In order to form the hollow regions 23 and 24 and the solid region 25 in the shaft 12, it is possible to exemplify a method of providing a filling material at a portion corresponding to the solid region 25 in a cylindrical member. The cylindrical member and the filling material may be made of the same material or different materials, the specific weights and rigidity of the materials may be the same as or different from each other. Also, the hollow regions 23 and 24 may be formed by trimming a solid round axial-shaped member at central axis positions on sides of end portions in the extending direction, and a non-cut portion may be formed as the solid region 25.
The hollow region 24 on the upper side (the side of the frame 13) in Figure 2A can be formed so as to be continuous with a space of the coupling portion 21 into which the joint 16 is inserted.
According to the aforementioned embodiment, since the hollow regions 23 and 24 and the solid region 25 are formed in the shaft body 22, it is possible to change the weight and the position of the center of gravity of the shaft 12 itself, and thus the weight and the balance point of the entire racket 10 can be adjusted by varying the lengths and the positions of the regions. As illustrated in Figure 2B, for example, it is possible to locate the balance point on the top end side by extending the hollow region 23 on the side of the grip 11 and shortening the hollow region 24 on the side of the frame 13 as compared with those in Figure 2A. In this manner, it is possible to perform adjustment in a so-called top-heavy direction, to increase inertia moment at the time of swinging of the racket 10, and to enhance a resilient force at the time of hitting the shuttlecock.
It is possible to adjust the weight and the balance point without changing the structures of the frame 13 and the grip 11 and also to adjust the weight and the balance point along with changes in designs of the frame 13 and the grip 11, by forming the shaft 12 in this manner. As a result, it is possible to enhance a degree of freedom in adjusting the weight and the balance point and to easily handle a wide range of variations in the racket 10.
Incidentally, shafts of badminton rackets made of metal or FRP are conventionally formed to be hollow. Here, the shaft is formed to be solid to secure strength while the diameter thereof is reduced in contrast with such a conventional structure, and since air resistance of the shaft at the time of swinging is reduced, it is thus possible to expect that swing-through performance is enhanced. However, the balance point of the entire racket is positioned on the rear end (grip) side in this case, and it may not be possible to state that functions such as resilience performance are sufficient.
Thus, the hollow regions 23 and 24 and the solid region 25 are formed in the shaft body 22, the hollow region 23 is provided on the side of the grip 11 as in the aforementioned embodiment, and the weight corresponding to the hollow region 23 can thus be allocated to the top end side of the shaft body 22. In this manner, it is possible to adjust the position of the center of gravity of the shaft 12 itself toward the top end thereof and thus the balance point of the entire racket 10 can be set toward the top end thereof and thereby to improve functions such as resilience performance. Furthermore, since the kick point KP is in the solid region 25, it is possible to secure strength against deflection of the shaft at the time of hitting. Thus, it is possible to satisfactorily maintain the position of the balance point and the strength of the shaft 12 and to realize an improvement in swing-through performance as a result of a decrease in diameter of the shaft 12.
As conventional adjustment of the weight and the balance point, there is a method of attaching a sheet made of lead or tungsten to an outer surface of the frame. However, in the case in which such a sheet is attached, the attached portion sticks out, and air resistance at the time of swinging changes, which affects a swinging speed. Also, the attached sheet degrades how the appearance looks like, and there may be a case in which the sheet unexpectedly peels off due to degradation with time or the like.
In this regard, according to the embodiment, it is possible to adjust the weight and the balance point depending on the inner structure of the shaft 12 and to avoid air resistance at the time of swinging as in the case of the attached sheet. Also, it is possible to prevent the appearance of the racket 10 from being affected and to prevent degradation with time and the like.
Note that the present invention is not limited to the aforementioned embodiment, and various modifications can be possible. The sizes, the shapes, the directions, and the like illustrated in the accompanying drawings in the aforementioned embodiment are not limited thereto and can be appropriately changed within a scope in which the advantages of the present invention are exhibited. In addition, the present invention can be implemented with appropriate modifications without departing from the scope of the purpose of the present invention.
Also, the lengths and the positions of the hollow regions 23 and 24 and the solid region 25 in the extending direction of the shaft body 22 are not limited to those in the illustrated configuration example and can be modified in various manners. For example, the hollow regions 23 and 24 provided at two locations herein may be formed at three or more locations, and a plurality of solid regions 25 may be formed. Alternatively, these may be formed with any one of the hollow regions 23 and 24 omitted. In addition, although the hollow regions 23 and 24 and the solid region 25 are formed to adjust the weight and the balance point, the solid region 25 may be partially formed at a location of the shaft 12 where strength is required, or in an opposite manner, the hollow regions 23 and 24 may be partially formed at locations where it is desirable to weaken the strength (it is desirable to increase deformation).
In addition, the coupling between the shaft 12 and the frame 13 is not limited to the aforementioned joint, and another coupling structure may be employed as long as it is possible to play badminton with it similarly to the racket 10 according to the aforementioned embodiment.

Industrial Applicability

The present invention relates to a badminton racket capable of enhancing a degree of freedom in adjusting a weight and a balance point.
The present application is based on Japanese Patent Application No. 2018-086015 filed on April 27, 2018 . The entire content thereof will be incorporated herein.

Claims

A badminton racket comprising:
a frame extending in an annular shape;

a grip; and

a shaft which extends and connects the grip and the frame each other,

wherein the shaft is formed to have at least one hollow region in a shaft body except for a coupling portion, at which the shaft is coupled to the frame, and to have at least one solid region which is arranged with the at least one hollow region in an extending direction.
The badminton racket according to claim 1, wherein the hollow region is formed in a region in which the shaft body is embedded in the grip.
The badminton racket according to claim 1 or 2, wherein the at least one solid region is formed in a region which includes a kick point in deflection of the shaft body.
The badminton racket according to any one of claims 1 to 3, wherein the hollow regions are formed on opposite sides of the shaft body in an extending direction.