WO2016195037A1

WO2016195037A1 - Racket

Info

Publication number: WO2016195037A1
Application number: PCT/JP2016/066468
Authority: WO
Inventors: 陽介山中; 大谷　和也; 武俊後藤
Original assignee: ヨネックス株式会社
Priority date: 2015-06-05
Filing date: 2016-06-02
Publication date: 2016-12-08
Also published as: CN107921313A; EP3305376A4; JPWO2016195037A1; US20180290027A1; EP3305376A1

Abstract

The present invention makes it possible to easily reveal different designs in a single racket. This racket (10) is provided with: a frame (13) that extends in an annular shape; a grip (11); and strings (14) that are stretched across the frame and form a ball hitting surface (15) on the front and rear surfaces. The frame and a shaft are provided with a first colored portion (41) and a second colored portion (42). When seen at a prescribed angle that is not parallel and not orthogonal to the ball hitting surface, the first colored portion can be seen and the second colored portion is hidden. When the ball hitting surface is inverted from this state, the second colored portion can be seen and the first colored portion is hidden.

Description

racket

The present invention relates to a racket capable of hitting a ball or shuttle on a hitting surface.

In racket sports such as badminton, tennis and squash, players play by swinging the racket and hitting the ball (or shuttle). The racket includes a frame formed in a loop shape, and a striking surface (face) is formed by stretching a string inside the frame (see Patent Document 1).

Japanese Patent Laying-Open No. 2015-8890

Conventional racket frames and shafts have various appearances depending on patterns, patterns, coloring, etc., but the design of such appearances is unified even when the viewing angle changes. It is common to become. On the other hand, the design preference varies depending on the changing season, physical condition, etc. even for the same player. Therefore, conventionally, in order to cope with various preferences, there is a problem that a burden of preparing rackets having different designs according to the preferences is forced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a racket capable of easily expressing different designs.

A racket according to the present invention includes a frame extending in an annular shape, a grip, a shaft that connects the frame and the grip, and a string that is stretched on the frame and forms both front and back surfaces as a striking surface. And at least one of the frame and the shaft includes a first coloring portion and a second coloring portion, and the first coloring when viewed at a predetermined angle that is non-parallel and non-orthogonal to the striking surface. The second colored portion is hidden while the portion is visible, and when the hitting surface is reversed from this state, the first colored portion is hidden while the second colored portion is visible.

According to this configuration, by changing the grip, one of the first colored portion and the second colored portion can be seen and the other can not be seen, and two different designs can be easily expressed by one racket. be able to. As a result, the appearance and impression of the racket viewed from the player can be greatly changed, and even if the player's design preference changes according to physical condition, environment, etc., this can be easily handled.

In the present invention, the first colored portion and the second colored portion are provided on the shaft, and the first colored portion is located on one side of the shaft center position when the ball striking surface is viewed from a direction orthogonal to the shaft. In addition, it is preferable that either one of the first coloring portion and the second coloring portion is provided on the other side of the axial center position of the shaft.

Further, in the present invention, the first coloring portion and the second coloring portion are provided on an outer surface of the frame, and when viewed from a direction orthogonal to the striking surface, the first coloring portion and the first coloring portion are located on one side of the shaft. Either one of the colored portion and the second colored portion may be provided, and the other of the first colored portion and the second colored portion may be provided on the other side from the axial center position of the shaft.

In the present invention, the first coloring portion and the second coloring portion are provided on an inner surface of the frame, and when viewed from a direction orthogonal to the striking surface, the first coloring portion and the second coloring portion are located on the other side of the shaft. Either one of the colored portion and the second colored portion may be provided, and either the first colored portion or the second colored portion may be provided on one side of the shaft center position of the shaft.

As described above, the first colored portion and the second colored portion can be provided at various positions, and design variations can be increased.

According to the present invention, the first colored portion and the second colored portion are visible or hidden when viewed at a predetermined angle and when the ball striking surface is reversed from this state. The design can be expressed easily.

FIG. 1A is an external view of a racket according to an embodiment of the present invention, FIG. 1A is a rear view of the racket, and FIG. 1B is a side view of the racket. FIG. 2 is a schematic cross-sectional view taken along the line AA in FIG. 1 for explaining the shape of the frame. FIG. 3 is a schematic sectional view taken along line BB in FIG. 1 for explaining the shape of the frame. FIG. 2 is a schematic cross-sectional view taken along the line BB of FIG. 1 for explaining the material of the frame. It is a partial rear view for demonstrating coloring of the said racket. It is a partial side view for demonstrating coloring of the said racket. It is a partial side view which shows the state which reversed the racket of FIG. It is a fragmentary perspective view for demonstrating coloring of the said racket. It is a fragmentary perspective view which shows the state which reversed the racket of FIG. 10A and 10B are cross-sectional views of the frame according to Example 1, and FIG. 10C is a cross-sectional view of the frame according to the comparative example. 6 is a cross-sectional view of a frame according to Embodiment 2. FIG. It is explanatory drawing of the experiment which measures the bending amount of the racket which concerns on Example 2. FIG.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is an external view of a badminton racket according to an embodiment of the present invention, FIG. 1A is a rear view of the badminton racket, and FIG. 1B is a side view of the badminton racket. In the following drawings, a part of the configuration is omitted for convenience of explanation.

As shown in FIG. 1, a badminton racket (hereinafter referred to as “racquet”) 10 includes a grip 11 held by a player, and a cylindrical shaft 12 that is connected to the grip 11 at one end and extends in a linear direction. And an elliptical frame 13 connected to the other end of the shaft 12. A string 14 is stretched inside the frame 13, and a striking surface 15 on which the shuttle is hit is formed by the string 14. The shaft 12 and the frame 13 are colored and the like will be described later.

In the claims and the description of the present specification, unless otherwise specified, as indicated by an arrow in FIG. 1, the side where the frame 13 is located in the longitudinal direction of the racket 10 is the front end side, and the grip 11 is The side that is positioned is the rear end side. Further, the direction orthogonal to the ball striking surface 15 is the front and back direction, the front side of the paper in FIG. 1A (the left side of the paper in FIG. 1B) is the back side, and the opposite side is the front side. Further, on the ball striking surface 15 (that is, on the plane along the ball striking surface 15), the direction orthogonal to the longitudinal direction is the left-right direction, and the left side and the right side are viewed from the back side of the racket 10 as shown in FIG. It is based on when.

The ball striking surface 15 formed by the string 14 is formed on both the front side and the back side. In playing badminton, there are cases where the forehand is hit and the backhand is hit, and when the shuttle flies to the hand holding the racket 10, the forehand and the shuttle flies to the opposite side of the hand holding the racket 10 It is common to hit with a hand. Then, due to the nature of the badminton swing, the striking surface 15 on which the shuttle is struck is reversed between the front hand and the back hand.

The frame 13 includes regions that become a top portion 13a, an intermediate portion 13b, and a sleeve portion 13c in order from the front end side to the rear end side in the longitudinal direction. The intermediate portion 13b is a predetermined width region including the position W at which the left and right width of the frame 13 is maximum, the top portion 13a is a front end side region from the intermediate portion 13b, and the sleeve portion 13c is a rear end side from the intermediate portion 13b. This is a region up to the connection position with the shaft 12. Although the top part 13a, the intermediate part 13b, and the sleeve part 13c are not particularly limited, they are regions of about 1/3 of the length of the frame 13 in the longitudinal direction.

The groove part 17 is provided in the outer peripheral surface in the site | part of the longitudinal direction center of the top part 13a in the flame | frame 13 from the intermediate part 13b. The string 14 (not shown in FIG. 1B) is folded and passed at the bottom of the groove portion 17 so that the string 14 contacts the floor even if the front end side in the longitudinal direction of the frame 13 hits or rubs against the floor. Is preventing.

Next, the cross-sectional shape of the frame 13 will be described below with reference to FIGS. 2 is a schematic cross-sectional view taken along line AA of FIG. 1 for explaining the shape of the frame, and FIG. 3 is a schematic cross-sectional view taken along line BB of FIG. 1 for explaining the shape of the frame. 2 and 3 are cross-sectional views of the frame 13 on a plane orthogonal to the extending direction of the frame 13. As shown in FIGS. 2 and 3, the frame 13 is formed by filling a predetermined foam material 19 inside a hollow cylindrical portion 18 having a predetermined thickness. The filling of the foam material 19 may be omitted in part or all of the frame 13. Examples of the material of the foam material 19 include urethane and acrylic. A specific configuration within the thickness of the cylindrical portion 18 will be described later.

In the range where the groove portion 17 is formed in the top portion 13a and the intermediate portion 13b of the frame 13 shown in FIG. 1, the cross-sectional shape shown in FIG. 2 or a slightly different cross-sectional shape is formed. Further, in the intermediate portion 13b and the skirt portion 13c of the frame 13, the cross-sectional shape shown in FIG. 3 or substantially the same cross-sectional shape is slightly different from the cross-sectional shape shown in FIG. It is formed.

Here, in the claims and the description of the present specification, the boundary position when the center axis position of the insertion hole 13d through which the string 14 (see FIG. 1A) is inserted is defined as the boundary position B1 unless otherwise specified. The exposed surface of the frame 13 positioned on the front side from B1 is defined as a surface portion 20. Further, the exposed surface of the frame 13 located on the back side from the boundary position B <b> 1 is defined as a back surface portion 21. Further, the vertical direction on the paper surface of FIGS. 2 and 3 is the outer / inner direction, the upper side in the figure is the outer side of the frame 13, and the lower side in the figure is the inner side of the frame 13. The boundary position B1 may be changed as appropriate within the thickness of the frame 13.

2 and 3, the front surface portion 20 and the back surface portion 21 of the frame 13 are formed in an asymmetric shape. Here, asymmetry means that the front surface portion 20 and the back surface portion 21 are not symmetric when the boundary position B1 is viewed as an axis of symmetry. It means that it does not become the same shape compared with the shape made. The front surface 20 and the back surface portion 21 have different widths in the front-back direction, and the width of the back surface portion 21 is larger.

The surface portion 20 is formed in a shape including a flat surface portion 25 and curved surface portions 26 continuous on both the outer and inner sides of the flat surface portion 25. The flat surface portion 25 is oriented substantially parallel to the outer / inner direction (the surface direction of the ball striking surface 15), and is formed in a shape in which a flat portion or a central portion in the outer / inner direction slightly swells. The flat surface portion 25 is formed in a region corresponding to the central portion divided into three when the surface portion 20 is equally divided into three in the outer and inner directions. The curved surface portion 26 is a curved surface formed in a quadrant arc shape in cross-sectional view, and an end portion on the opposite side to the flat surface portion 25 is directed to the back side.

The back surface portion 21 is formed in a shape including an arcuate surface portion 27 that is a curved surface portion and inclined surface portions 28 that are continuous on both the inside and outside of the arcuate portion 27. The arcuate surface portion 27 presents a curved surface having a quadrant arc shape formed so that the center portion in the outer-inward direction swells most in the back direction when viewed in cross section. The arcuate surface portion 27 is set so that its most bulging position is located outside the middle in the outer-inward direction of the frame 13. Each inclined surface part 28 is formed in a substantially flat shape, and extends in a direction away from each other toward the front side. The outer and inner inclined surface portions 28 extend in the tangential direction at the outer and inner end portions of the arcuate surface portion 27.

In the surface portion 20 and the back surface portion 21 in the region of the cross section of FIG. 3, the peripheral surfaces on both the outer and inner sides of the frame 13 straddling the boundary position B1 are smoothly curved and bulging

surfaces

30, 31 in which the center in the front and back direction bulges out. It is formed as. In addition, the curvature of the curved surface part 26 which becomes a curved surface, the arc-shaped surface part 27, and the bulging

surfaces

30 and 31 is set to be larger in the order of the arc-shaped surface part 27, the curved surface part 26 and the bulging

surfaces

30 and 31. 2, the groove portion 17 is formed in a region corresponding to the outer bulging surface 30, and the inner bulging surface 31 in FIG. 2 and the inner bulging surface 31 in FIG. 3 are formed in the same shape. Is done.

According to the above-described shape, since the front surface portion 20 and the back surface portion 21 are formed in an asymmetric shape, the generated stress distribution and the cross-sectional shape are different depending on whether the hit ball on the hitting surface 15 is on the front side or the back side. The amount of deformation and the shape of deformation are different. Further, the cross-sectional secondary moment of bending deformation or the like of the frame 13 can be changed depending on whether the hit ball on the hitting surface 15 is on the front side or on the back side. Thereby, on the front and back of the ball striking surface 15, it is possible to change the time when the shuttle contacts the ball striking surface 15 at the time of striking, the resilience performance, and the like, and it is possible to change the performance related to striking such as holding the ball and playing performance. As a result, the player can simply change the grip 11 and easily perform two different types of performance with one racket 10 without changing the racket 10, and respond to preferences such as age, sex, and technical level that differ depending on the player. Can be easily handled.

Here, when further consideration is given to playing badminton, in comparison between the forehand and the backhand, the forehand tends to increase the shuttle speed in order to quickly shoot the shuttle onto the court, and the swing speed increases accordingly. The swing trajectory tends to be long. On the other hand, the backhand tends to have a shorter swing trajectory, and the backhand is often hit back to play the shuttle on a course that is difficult for the opponent to hit.

However, like the conventional badminton racket, when the front and back parts of the frame are symmetrical, the same performance as the frame can be achieved even if the forehand and the backhand require different hit balls as described above. It must be demonstrated. In other words, if the frame shape is designed for the performance corresponding to the forehand, the performance of the backhand is degraded, and conversely, if the frame shape is designed for the performance corresponding to the backhand, the performance of the forehand is degraded. There is.

In this regard, in the frame 13 of the present embodiment, different ball holding and playing performances can be realized on the front and back of the ball striking surface 15, and as described above, performance improvement according to the characteristics of both the forehand and the backhand Can be achieved.

Further, since the front surface portion 20 and the back surface portion 21 are formed in an asymmetric shape, the air resistance received by the frame 13 between the forehand and the backhand can be changed. It can be expected to improve the performance according to the properties.

Subsequently, the material of the frame 13 will be described below with reference to FIG. 4 is a cross-sectional view taken along the line BB in FIG. 1 for explaining the material of the frame. Here, as shown in FIG. 4, the cylindrical portion 18 of the frame 13 includes a front surface side forming body 35 that forms the front surface portion 20 and a back surface side forming body 36 that forms the back surface portion 21. Either one of the front surface side formed body 35 and the back surface side formed body 36 is formed to include a deflection suppressing portion 37 as a material different from either one. In the present embodiment, the bending suppression portion 37 is disposed as a layer that fits within the thickness in a region corresponding to the flat surface portion 25 and the outer and inner curved surface portions 26 in the surface-side formed body 35.

The wire 38 is disposed at the most bulged position of the arcuate surface portion 27 in the back surface side formed body 36. The wire 38 increases the flexural modulus and hardness of the frame 13, and can be exemplified by using a material such as titanium, stainless steel, or boron in addition to a titanium alloy.

In forming the cylindrical portion 18, after forming the tube of the resin sheet, the tube is curved in an annular shape, and then installed in the mold, and then heated and pressurized, so that it is aligned with the mold. Shape. The cylinder of the resin sheet is formed by laminating a plurality of carbon prepreg sheets (prepreg-like fiber reinforced resin (FRP) mainly composed of carbon fibers, hereinafter referred to as “main sheet”) that mainly form the cylinder portion 18. It is formed by winding in a cylindrical shape. In this lamination, the bending suppression portion 37 is formed between the plurality of main sheets so that the bending suppression portion 37 is disposed in a region corresponding to the planar portion 25 and the outer and inner curved surface portion 26 after molding. A band-shaped carbon prepreg sheet is interposed. Moreover, the said wire 38 is interposed between several main sheets so that the wire 38 may be arrange | positioned in the area | region corresponding to the circular-arc-shaped surface part 27 after shaping | molding. Thereby, in the frame 13 after molding, the bending suppressing portion 37 is formed within the thickness of the front surface side formed body 35, and the wire 38 is disposed within the thickness of the back surface side formed body 36.

Here, the carbon prepreg sheet forming the bending suppression portion 37 becomes a molded body having a bending strength of 1800 MPa to 2000 MPa and a bending elastic modulus of 155 GPa to 175 GPa after molding. In the case where a plurality of carbon prepreg sheets forming the bending suppressing portion 37 are used, the bending strength and bending elastic modulus of the sheets may be the same or different as long as they are within the above ranges. Good. Moreover, the main sheet becomes a molded body having a bending strength of 1600 MPa or more and less than 1800 MPa and a bending elastic modulus of 135 GPa or more and less than 155 GPa after molding. In addition, as long as the some main sheet is in the said range, bending strength and a bending elastic modulus may be the same, and may differ respectively.

Here, in the conventional badminton racket made of the same material on the front and back of the frame 13, as in the case described above, even if a hit ball having a different property from the forehand and the backhand is required, the same performance as the frame must be exhibited. . In this regard, by providing the frame 13 with the bending suppressing portion 37 and the wire 38, the bending strength and the bending elastic modulus of the frame 13 change depending on whether the hit ball on the hitting surface 15 is on the front side or the back side. The bending amount of the frame 13 can be changed. Therefore, this also makes it possible to change the performance related to hitting, such as holding the ball and playing performance as described above, on the front and back of the hitting surface 15. As a result, two different types of performance can be easily achieved with one racket 10 without changing the racket 10, and performance can be improved in accordance with the properties of both the forehand and the backhand.

Also, the combination of the shape in which the front surface portion 20 and the rear surface portion 21 of the frame 13 are asymmetric and the provision of the bending suppression portion 37 can synergistically increase variations in performance relating to impact.

Next, the coloring of the shaft 12 and the frame 13 will be described below with reference to FIGS. 5 to 9 are diagrams for explaining the coloring. FIG. 5 is a partial rear view of the racket, FIG. 6 is a partial side view of the racket, and FIG. 7 is an inverted version of the racket of FIG. It is a partial side view which shows the state. 8 is a partial perspective view, and FIG. 9 is a partial perspective view showing a state in which the racket of FIG. 8 is inverted.

In the shaft 12 and the frame 13, there are mainly three colors of the first coloring portion 41, the second coloring portion 42, and the main coloring portion 43 that is almost the area other than the first coloring portion 41 and the second coloring portion 42. They are color-coded. Accordingly, the first coloring portion 41 and the second coloring portion 42 are also expressed as patterns and patterns on the shaft 12 and the frame 13. 5 to 9, for the convenience of illustration, the halftone area is the first colored portion 41, the black area is the second colored area 42, and the white area (paper color) is the main color area. Part 43 is assumed. The actual coloring may be any color as long as the coloring portions 41 to 43 are different. The first coloring portion 41 may be orange, the second coloring portion 42 may be green, and the main coloring portion 43 may be black. It can be illustrated.

In the present embodiment, the first coloring portion 41 is formed in five regions of the shaft 12 and the frame 13. For convenience of explanation, these five areas are defined as the 1-1 colored portion 41a to the 1-5 colored portion 41e. When the racket 10 is viewed from the back side as shown in FIG. become that way.
1-1 colored portion 41a: right side surface of shaft 12 1-2 colored portion 41b: outer surface behind position W in right half portion of frame 13 1-3 colored portion 41c: in right half portion of frame 13 Outer side surface ahead of position W 1-4 colored portion 41d: inner side surface behind position W in left half of frame 13 1-5 colored portion 41e: inside ahead of position W in left half of frame 13 side

The 1-1 colored portion 41a does not protrude to the left from the central position in the left-right direction of the shaft 12, and is formed within a range that fits to the right from the central position. In the present embodiment, the 1-1 colored portion 41a is formed near the front end and the rear end of the shaft 12, and is provided so that the main colored portion 43 appears between them. Further, the 1-1 colored portion 41a is formed such that the portion that appears closer to the rear end is longer in the longitudinal direction than the portion that appears closer to the tip.

The 1-2 colored portion 41b and the 1-3 colored portion 41c are provided on the right half of the frame 13, in other words, on the right side which is one side of the shaft 12. The first-second coloring portion 41b and the first-third coloring portion 41c are formed within a range that does not protrude from the center position in the outer-inward direction of the frame 13 but falls outside the center position. In the present embodiment, the 1-2 colored portion 41b and the 1-3 colored portion 41c extend in the extending direction of the frame 13, and are provided so that the main colored portion 43 appears between them. . In addition, the main coloring portion 43 also appears between the rear end of the 1-2 colored portion 41b and the rearmost end of the frame 13 and between the front end of the 1-3 colored portion 41c and the most distal end of the frame 13. Is provided.

The first to fourth colored portions 41d and the first to fifth colored portions 41e do not protrude outward from the center position in the outer-inward direction of the frame 13, and are formed within a range that falls inside the center position. In the present embodiment, the first to fourth coloring portions 41d and the first to fifth coloring portions 41e extend in the extending direction of the frame 13, and are provided so that the main coloring portion 43 appears between them. . In addition, the 1-4 colored portion 41d is divided into three parts, the main colored portion 43 appears between them, and also between the rear end of the 1-4 colored portion 41d and the rearmost end of the frame 13. It is provided so that the main coloring part 43 appears. Further, the main coloring portion 43 is provided between the front end of the first to third coloring portion 41 c and the forefront of the frame 13.

The second colored portion 42 of the present embodiment is formed in a region that is symmetrical to the first colored portion 41 with the center position (axis center position) in the left-right direction of the shaft 12 as the symmetry axis S. Accordingly, the second colored portion 42 is also formed in five regions. For convenience of explanation, if these five regions are referred to as the 2-1 colored portion 42a to the 2-5 colored portion 42e, these formed regions are The 1-1 colored portion 41a to the 1-5th colored portion 41e are formed symmetrically with respect to the symmetry axis S. In other words, when the racket 10 is inverted from the state shown in FIG. 1, the 2-1 colored portion 42a is formed in the region where the 1-1 colored portion 41a to the 1-5 colored portion 41e are formed before the inversion. The second to fifth colored portions 42e are arranged. Therefore, the description of the formation region of the 2-1 colored portion 42a to the 2-5 colored portion 42e is omitted here.

When the racket 10 is viewed at a predetermined angle that is non-parallel and non-orthogonal to the ball striking surface 15, for example, when the racket 10 is viewed as shown in FIG. The first colored portion 41 appears in the half area. Although it looks like this, the main coloring portion 43 appears to appear in the remaining approximately half region, and the second coloring portion is hidden. Therefore, the player looks like the two-color racket 10 of the first coloring portion 41 and the main coloring portion 43. At this time, the lower side is the front side and the upper side is the back side of the frame 13 and the hitting surface 15 in FIG. Can be identified.

On the other hand, when the grip 11 is changed from the state shown in FIG. 8 and the racket 10 is rotated by 180 ° around the shaft 12 (the hitting surface not shown is reversed), the state shown in FIG. 9 is obtained. At this time, the player looks like the second colored portion 42 appears in the approximately half region of the shaft 12 and the frame 13, while the main colored portion 43 appears to appear in the remaining approximately half region. The colored part is hidden. Therefore, the player looks like a two-color racket 10 of the second coloring portion 42 and the main coloring portion 43. At this time, the lower side is the back side and the upper side is the front side of the frame 13 and the hitting surface 15 in FIG. Can be identified.

In addition, when it rotates ± 90 degrees around the axis of the symmetry axis S from the state shown in FIG. 5, it will be in the state shown in FIG. 6 and FIG. 7, and any one of the 1st coloring part 41 and the 2nd coloring part 42 will become. It becomes a hidden state. The angle at which any one of these is hidden is preferably in a range rotated ± 20 ° around the axis of symmetry S from the state shown in FIGS.

The first coloring portion 41 and the second coloring portion 42 illustrated in FIGS. 5 to 9 are merely examples, and various modifications are possible as long as the front and back sides can be identified as described above. For example, each of the five

colored areas

41 and 42 described above of the first colored part 41 and the second colored part 42 may be at least one, and the shape in each of the five colored areas is also illustrated. It is not limited to the example shown. Further, for example, the first-second coloring portion 41b and the first-third coloring portion 41c may be connected, or the first-fourth coloring portion 41d and the first-fifth coloring portion 41e may be connected.

Furthermore, the colors of the first coloring portion 41 and the second coloring portion 42 may be a single color, or may be expressed like a pattern using a plurality of similar colors. Further, when the first colored portion 41 and the second colored portion 42 are hidden by the player when viewed at a predetermined angle, it is not necessary to completely hide them, and a design in which a part of the colored portions intentionally protrudes may be adopted. Good. Furthermore, it does not prevent the colored portions 41 to 43 from being provided with characters, marks, logos, patterns, patterns, and the like. Further, when using grommets, the coloring portions 41 to 43 in the frame 13 may color the grommets.

As described above, since the colored portions 41 to 43 are provided on the racket 10, the player can easily identify the front and back of the batting surface 15 depending on whether the first colored portion 41 and the second colored portion 42 are visible. The ball hitting surface 15 can be easily selected. Therefore, as described above, when the performance (ball holding performance and playing performance) relating to the hit is different between the front and back of the hitting surface 15, the player can easily use different performances during the play and the rally.

Further, the design of the racket 10 can be greatly changed between the state of FIG. 8 and the state of FIG. 9, and two different designs can be easily expressed by one racket 10. As a result, the appearance and impression of the racket 10 as seen from the player can be greatly changed, and even if the player's design preferences change, this can be easily accommodated. Note that how the player sees the image differs depending on the hand holding the racket 10 (right hand or left hand).

Subsequently, an analysis (simulation) performed to evaluate the ball holding and playing performance of the racket according to the above embodiment will be described with reference to FIG. 10A and 10B are cross-sectional views of the frame according to Example 1, and FIG. 10C is a cross-sectional view of the frame according to the comparative example. In this analysis, the racket of Example 1 has the same shape as that illustrated in the above embodiment, and is a racket including the frame 13 having a cross-sectional shape shown by a two-dot chain line in FIGS. 10A and 10B. However, the material of the racket of Example 1 was the frame 13 formed by the above-described main sheet without using the above-described bending suppressing portion 37 and the wire 38 (see FIG. 5). The racket of the comparative example has the same configuration and conditions as in Example 1 except that the cross-sectional shape of the frame 13 'is changed to the shape indicated by the two-dot chain line in FIG. 10C. The frame 13 ′ of the comparative example has a front and back symmetrical shape similar to an ellipse in a cross-sectional view, and has a shape in which only the upper half in FIG.

Using the racket of Example 1 and the racket of the comparative example, the cross-sectional displacement and stress distribution of the frames 13, 13 'at the time of hitting were analyzed. In the simulation of the cross-sectional displacement, the cross-sectional shape when the load F was applied on the assumption that the shuttle was hit at a sweet spot of the hitting surface at a predetermined relative speed was obtained. In the racket of Example 1, the simulation was performed both when the shuttle was hit on the front side of the hitting surface, that is, the left side in FIG. 10A, and when the shuttle was hit on the back side of the hitting surface, that is, the right side in FIG. In the racket of the comparative example, a simulation was performed when the shuttle was hit on the left side in FIG. In FIG. 10A to FIG. 10C, the simulation results of the cross-sectional shape when the maximum displacement is obtained by each impact are indicated by solid lines, and the relative value of the maximum displacement in Example 1 is set with the value of the maximum displacement of the comparative example being 100. It is shown in Table 1 below.

Also, the stress distribution of the

frames

13 and 13 ′ when hit similarly was obtained, and the maximum stress at which the stress becomes the largest was obtained. The relative value of the maximum stress in Example 1 with the value of the maximum stress of the comparative example as 100 is shown in Table 1 below.

As can be understood from the results in Table 1, the maximum stress is larger and the maximum displacement is larger when the ball is hit on the front side than when the ball is hit on the back side. This makes it possible for the player to feel the difference in performance between the ball holding performance and the playing performance on the front and back of the hitting surface.

Subsequently, an experiment conducted for evaluating the bending performance of the racket according to the above embodiment will be described. In this experiment, a racket having a frame having a cross-sectional shape shown in FIG. FIG. 11 is a cross-sectional view of the frame according to the second embodiment. The frame 13 of Example 2 has a front and back symmetrical shape, and the back side and the front side are formed in the same shape as the surface portion 20 (see FIG. 2) of the above embodiment. In addition, the frame 13 of Example 2 is configured to include the above-described bending suppression portion 37, but was molded without using the wire 38 and the foam material 19. Moreover, the bending suppression part 37 sets bending strength to 1800 MPa or more and 2000 MPa or less, a bending elastic modulus to 155 GPa or more and 175 GPa or less, and the part formed with main sheets other than the bending suppression part 37 has bending strength of 1600 MPa or more. The bending elastic modulus was set to 135 GPa or more and less than 155 GPa.

FIG. 12 is an explanatory diagram of an experiment for measuring the bending amount of the racket according to the second embodiment. As shown in FIG. 12, in this experiment, the grip 11 of the racket 10 is fixed, a predetermined load F is applied to the front end side of the frame 13, and the front and back directions at the front end of the frame 13 before the load F is applied. The amount of deformation was measured as a bending amount. This measurement was performed both when the load F was applied from the front side of the frame 13 and when the load F was applied from the back side. In this measurement, when the value of the bending amount when the load F is applied from the front side is 100 (see FIG. 12A), the relative value of the bending amount when the load F is applied from the back side is 102 to 105 (FIG. 12B).

As can be understood from the above measurement results, when the bending suppression part 37 is arranged on the direction to which the load F is applied (the direction of hitting the shuttle), compared to the case where the bending suppression part 37 is arranged on the opposite side, The bending amount becomes smaller. Therefore, when the ball is hit on the front side, power can be improved and the ball can be held by crushing the shuttle at the time of hitting due to the action of the bending suppression portion 37 having high rigidity.

It should be noted that the present invention is not limited to the above embodiment, and can be implemented with various modifications. In the above-described embodiment, the size, shape, direction, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

For example, the front and back of the racket 10 may be distinguished from those in the above-described embodiment. In the direction orthogonal to the hitting surface 15, either one may be the front side and the opposite side may be the back side.

Moreover, the shape of the cross-sectional view in the plane orthogonal to the extending direction of the frame 13 may be changed. For example, in a cross-sectional view of the frame 13, a plurality of portions protruding in the front and back direction may be formed, or a recessed portion may be formed.

Further, the formation position, the formation range, and the number of installations of the bending suppression portion 37 are not limited to the configuration shown in FIG. 4, and various changes can be made. For example, the bending suppression part 37 may be divided and provided in the outer / inner direction, may be provided only on the flat part 25 without being provided on the curved surface part 26, or may be provided in a plurality of layers in the thickness direction of the cylindrical part 18.

Moreover, the bending suppression part 37 and the wire 38 may be provided continuously in all of the extending direction of the frame 13 or may be provided in a part of the extending direction.

Further, the shape of the frame 13 may be changed to a cross-sectional shape that is symmetric with respect to the front and back. It may be formed.

Further, the present invention may be applied to soft tennis, a soft tennis racket, a squash racket, or the like. At this time, the shape of the shaft 12 may be bifurcated.

This application is based on Japanese Patent Application No. 2015-114813 filed on June 5, 2015. All this content is included here.

Claims

A racket comprising an annularly extending frame, a grip, a shaft connecting the frame and the grip, and a string stretched on the frame to form both front and back surfaces as a striking surface,
At least one of the frame and the shaft includes a first coloring portion and a second coloring portion,
When viewed at a predetermined angle that is non-parallel and non-orthogonal to the ball striking surface, the first colored portion is visible while the second colored portion is hidden, and when the ball striking surface is reversed from this state, A racket characterized in that the first colored portion is hidden while the second colored portion is visible.
The first colored portion and the second colored portion are provided on the shaft,
When the ball striking surface is viewed from a direction perpendicular to the shaft, either one of the first coloring portion and the second coloring portion is provided on one side of the shaft center position of the shaft, and the other is from the shaft center position of the shaft. The racket according to claim 1, wherein either one of the first coloring portion and the second coloring portion is provided on a side.
The first colored portion and the second colored portion are provided on an outer surface of the frame,
When the ball striking surface is viewed from a direction perpendicular to the shaft, either one of the first coloring portion and the second coloring portion is provided on one side of the shaft, and the first coloring portion and the second coloring portion are provided on the other side of the shaft center position. The racket according to claim 1 or 2, wherein one of the first colored portion and the second colored portion is provided.
The first colored portion and the second colored portion are provided on an inner surface of the frame,
When the ball striking surface is viewed from a direction perpendicular to the shaft, either one of the first coloring portion and the second coloring portion is provided on the other side of the shaft, and the first coloring portion and the second coloring portion are provided on one side of the shaft center position. The racket according to any one of claims 1 to 3, wherein one of the first colored portion and the second colored portion is provided.