JP2000189544A - Badminton racket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve flexibility of a shaft. SOLUTION: Concerning at least a part of a shaft part S of a badminton racket 1, a cross section vertical to its axis is nearly diamond-shaped and the longer diagonal of the diamond shape is arranged in parallel with the racket face surface 10 of a frame part F. In this case, at the time of the forehand swing of a right-handed player and the back swing of a left-handed player, the curving rigidity of the part S is lowered to improve flexibility of the part S, thereby the head speed of the racket is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a badminton racket, and more particularly to an improvement in the structure of a shaft portion thereof.

[0002]

2. Description of the Related Art In general, a badminton racket includes a frame on which a gut is stretched to define a racquet face, a grip, and a shaft connecting the frame and the grip. As a sectional shape of a shaft portion of a conventional badminton racket, a circular shape as disclosed in Japanese Patent No. 2501277 and a rectangular shape as disclosed in Japanese Utility Model Laid-Open No. 55-175455 have been proposed.

[0003] When a badminton player hits a shuttlecock above himself with a forehand, for example, he takes back the racket and swings it behind his head, and swings the racket upward from this state to hit the shuttlecock. It is normal to swing out,
At this time, a series of swings before and after hitting the shuttlecock are performed within a certain plane in the space (hereinafter, referred to as “swing plane”).

[0004] The badminton player of the middle-advanced level or higher hits the shuttlecock by swinging the racket from a state where the racket face is inclined by about 80 ° to 45 ° with respect to the swing plane during takeback, and hits the shuttlecock. The racket is swinging out while rotating the racket surface by about 80 ° to 10 ° in the opposite direction to the above with a grip.

[0005] Therefore, when the racket is shaken out of the racket, that is, at the time of takeback, the shaft of the racket forms a direction of about 80 ° to 45 ° with the racket face surface (especially as it approaches the grip side). A large bending moment will act.

[0006] However, if the shaft has a conventional circular or rectangular cross-sectional shape, the shaft has a height of about 80 mm.
For a badminton racket having an appropriate bending rigidity with respect to the axis in a region other than the region forming an angle of 45 ° to 45 °, the bending rigidity of the axis forming an angle of approximately 80 ° to 45 ° with the racket face surface is large. For this reason, the shaft cannot be sufficiently bent at the time of takeback, and as a result, it is not possible to increase the head speed using the restoring force of the bending of the shaft.

[0007] The cross-sectional shape of the shaft is a conventional circular or rectangular shape, and is approximately 80 ° or less from the racket face surface.
Regarding the badminton racket in which the bending rigidity with respect to the axis in the region forming 45 ° is moderate, the bending rigidity with respect to the axis in the region other than the region forming approximately 80 ° to 45 ° with the racket face surface is excessively or insufficient.

For this reason, during the swing other than the takeback, an undesirable shaft deformation behavior occurs,
There is a possibility that the shuttlecock cannot be controlled.

Further, in the case of a conventional circular or rectangular cross-sectional shape of the shaft, a cross-section of substantially the same shape and the same dimension from the frame side to the grip side of the shaft, or a slightly tapered shaft, the cross-section of which approaches the grip side. For badminton rackets with slightly larger dimensions, a large bending moment acts on the grip side of the shaft, especially during takeback, making it easier for undesired shaft deformation behavior to occur and controlling the shuttlecock. There is a considerable possibility that it will disappear.

The present invention has been made in view of such a conventional situation, and an object of the present invention is to provide a badminton racket capable of improving the flexibility of the entire shaft. Another object of the present invention is to realize a badminton racket according to a play style.

[0011]

A badminton racket according to the first aspect of the present invention is a badminton racket comprising a frame defining a racket face, a grip, and a shaft connecting the frame and the grip. A cross section perpendicular to the axis of at least a part of the shaft has a substantially rhombic shape.

A badminton racket according to a second aspect of the present invention is characterized in that, in the first aspect, one diagonal line of the rhombus is arranged to be parallel to the racket face surface.

According to a third aspect of the present invention, in the badminton racket according to the second aspect, the longer diagonal line of the rhombus is arranged so as to be parallel to the racket face surface.

A badminton racket according to a fourth aspect of the present invention is characterized in that, in the second aspect, the shorter diagonal line of the rhombus is arranged so as to be parallel to the racket face surface.

The badminton racket according to a fifth aspect of the present invention is the badminton racket according to the third or fourth aspect, wherein a length of a diagonal of the rhombus-shaped diagonal perpendicular to the racket face surface is determined by a frame-side cross-section and a grip-side cross-section. Equal or
Alternatively, the grip side section is longer than the frame side section.

According to a sixth aspect of the present invention, in the badminton racket according to the fifth aspect, the cross-sectional shape of the shaft on the side of the frame connecting portion is substantially circular.

A badminton racket according to a seventh aspect of the present invention is the badminton racket according to the fifth or sixth aspect, wherein a diagonal length a1 perpendicular to the racket face surface in the frame side section is 4 to 10 mm, and the racket in the grip side section. Diagonal length a2 perpendicular to the face surface is 5
20 mm, and a1 ≦ a2.

The badminton racket according to the invention of claim 8 is characterized in that, in claim 7, the cross-sectional shape of the shaft on the frame connecting portion side is substantially circular and the outer diameter is a1.

A badminton racket according to a ninth aspect of the present invention is the badminton racket according to the seventh or eighth aspect, wherein a length of a diagonal line parallel to the racket face surface in the cross section on the grip side is b2, 1 <b2 / a2 ≦ 2 or 0.
It is characterized in that 5 ≦ b2 / a2 <1.

According to a tenth aspect of the present invention, in the badminton racket according to the third aspect, at least a part of a shaft portion having a rhombus-shaped cross section is located at both ends of a shorter diagonal of the rhombus in an axial direction. At least one of the corner portions has a flat portion substantially parallel to the racket face surface.

According to the eleventh aspect of the present invention, in the badminton racket according to the first aspect, one of the rhombus-shaped diagonal lines is rotated within a range of 0 ° to 180 ° with respect to the racket face. Features.

According to a twelfth aspect of the present invention, in the badminton racket according to the eleventh aspect, one of the diagonal lines of the rhombus is formed at an angle of 5 ° from a position parallel to the racket face surface.
It is characterized by being arranged to be rotated in the range of 70 ° or 110 ° to 175 °.

According to a thirteenth aspect of the present invention, in the badminton racket according to the twelfth aspect, the shorter one of the rhombus-shaped diagonals is 5 ° to 70 ° or 110 ° or less from a position parallel to the racket face surface. It is characterized by being arranged to rotate within a range of 175 °.

According to a fourteenth aspect of the present invention, in the badminton racket according to the twelfth aspect, the longer one of the diamond-shaped diagonals is shifted from a position parallel to the racket face by 5 ° to 70 ° or 110 °. It is characterized by being arranged to rotate within a range of 175 °.

According to a fifteenth aspect of the present invention, in the badminton racket according to the thirteenth or fourteenth aspect, the length of the shorter one of the rhombus-shaped diagonals is equal between the frame-side cross-section and the grip-side cross-section. Alternatively, the grip side section is longer than the frame side section.

A badminton racket according to a sixteenth aspect of the present invention is characterized in that, in the fifteenth aspect, the cross-sectional shape of the shaft on the side of the frame connecting portion is substantially circular.

A badminton racket according to a seventeenth aspect of the present invention is the badminton racket according to the fifteenth or sixteenth aspect, wherein a shorter diagonal length a of the diagonals in the cross section on the frame side is a
1 is 4 to 10 mm, the length a2 of the shorter one of the diagonals in the grip-side section is 5 to 20 mm, and a1 ≤ a2.

An eighteenth aspect of the present invention provides the badminton racket according to the seventeenth aspect, wherein the shaft has a substantially circular cross-sectional shape on the frame connecting portion side and an outer diameter of a1.

The badminton racket according to the nineteenth aspect of the present invention is the badminton racket according to the seventeenth or eighteenth aspect, wherein 1 <b2 / a2≤2, where b2 is the longer diagonal of the diagonals on the grip side section. It is characterized by having.

According to a twentieth aspect of the invention, there is provided a badminton racket according to any one of the first to nineteenth aspects, wherein the extended end of the shaft connected to the inside of the grip has a substantially circular cross section. It is characterized by.

In the badminton racket according to the first aspect of the present invention, since at least a part of the shaft has a substantially rhombic cross section perpendicular to the axis thereof, the following effects can be obtained.

That is, for example, when the rhombic cross section is arranged such that the longer diagonal line of the rhombic shape is parallel to the racket face surface, the angle θ (0
The bending stiffness for a neutral axis that satisfies ° <θ <45 ° and 135 ° <θ <180 °) is generally smaller than in the case of a circular or rectangular section. Thereby, the shaft can be sufficiently bent at the time of takeback, and the head speed of the racket can be increased by utilizing the restoring force of the bending of the shaft.

[0033] One of the diagonal lines of the rhombus may be arranged so as to be parallel to the racket face surface as described in the second aspect of the present invention. The diagonal that is placed is
It may be a long diagonal line of a rhombus shape as described in the third aspect of the invention, or a shorter diagonal line as described in the fourth aspect of the invention.

When the longer diagonal line of the rhombus is arranged parallel to the racket face, the flexibility of the shaft during takeback can be improved as described above. When the shorter diagonal of the rhombus is arranged parallel to the racket face, the angle θ (0
The bending stiffness for a neutral axis that satisfies ° <θ <45 ° and 135 ° <θ <180 °) is generally greater than for a circular or rectangular cross section.

In this case, since the racket face surface is unlikely to bend in the front-rear direction, the take-back is small and the shuttlecock is hit with a fast operation. The face can be quickly brought to the shuttlecock. For this reason, a badminton racket that is particularly effective when advancing a double spray can be realized.

According to the fifth aspect of the present invention, the length of the diagonal perpendicular to the racket face is equal in the frame-side section and the grip-side section, or is longer in the grip-side section than in the frame-side section. Here, usually, during a swing, particularly during takeback, the bending moment applied to the shaft by the action of inertia is small on the frame side of the shaft and large on the grip side. Therefore, by setting the length of the diagonal line orthogonal to the racket face surface as in this case, the amount of deflection of the shaft during the swing can be controlled, and the shaft can be bent smoothly, and Swing feeling given to the player.

The cross-sectional shape of the shaft on the frame connecting portion side may be substantially circular as described in the sixth aspect of the present invention. In this case, work such as polishing and reinforcement of the frame connecting portion of the shaft is facilitated, thereby improving workability.

As described in the invention of claim 7,
The diagonal length a1 perpendicular to the racket face surface in the cross section on the frame side is 4 to 10 mm, and the diagonal length a2 perpendicular to the racket face surface in the cross section on the grip side is 5 mm.
It is preferable that a1 ≤ a2.

As described in the invention of claim 8,
The cross-sectional shape of the shaft on the frame connecting portion side may be substantially circular and the outer diameter may be a1.

As described in the ninth aspect of the present invention,
When the length of the diagonal line parallel to the racket face surface in the cross section on the grip side is b2, when the longer diagonal line of the diamond shape is arranged so as to be parallel to the racket face surface, 1 <b2 / a2≤2. In the case where the shorter diagonal line of the rhombus is arranged so as to be parallel to the racket face surface, 0.5 ≦ b2
It is preferable that the relationship of / a2 <1 is satisfied.

According to the tenth aspect of the present invention, at least a part of each of the corners located at both ends of the shorter diagonal of the rhombus in at least a part of the shaft portion having the rhombus-shaped cross section in the axial direction. Either one may have a plane portion substantially parallel to the racket face surface.

In this case, the place where the plane portion is formed becomes a kick point (flexible point), and the degree of flexure of the shaft can be adjusted by appropriately changing its length, width and formation position, and can be adjusted according to the play style. Racket can be realized.

As described in the eleventh aspect of the present invention, one of the rhombic diagonal lines may be arranged to rotate within a range of 0 ° to 180 ° with respect to the racket face surface. In this case, as described in the twelfth aspect, the rotation angle is 5 ° to 70 ° or 110 ° to 175.
Is preferable, and the most preferable range of the rotation angle is 10 ° to 50 ° or 130 ° to 170 °.

5 ° to 70 ° with respect to the racket face
Or 110 ° -175 ° (most preferably 10 ° -5
The diagonal line rotated within the range of 0 ° or 130 ° to 170 °) is as described in the invention of claim 13.
Even the shorter diagonal of the diamond-shaped diagonals,
Further, as described in the fourteenth aspect of the present invention, the longer one of the diamond-shaped diagonals may be used.

According to the fifteenth aspect, the shorter one of the rhombic diagonal lines is equal in the frame-side section and the grip-side section, or is longer in the grip-side section than in the frame-side section. ing. As a result, the amount of deflection of the shaft during the swing can be controlled, and the shaft can be smoothly bent.
The swing feeling given to the player can be improved.

As described in the sixteenth aspect, the cross-sectional shape of the shaft on the side of the frame connecting portion may be substantially circular. In this case, work such as polishing and reinforcement of the frame connecting portion of the shaft is facilitated, thereby improving workability.

According to the seventeenth aspect of the present invention, the length a1 of the shorter one of the diagonals in the cross section on the frame side is 4 to 10 mm, and the shorter one of the diagonals in the cross section on the grip side. Length a2 is 5-2
0 mm, and it is preferable that a1 ≤ a2.

As described in the eighteenth aspect of the present invention, the cross-sectional shape of the shaft on the frame connecting portion side may be substantially circular and the outer diameter may be a1.

As described in the nineteenth aspect, the length of the longer diagonal in the cross section on the grip side is b
When it is set to 2, it is preferable that 1 <b2 / a2 ≦ 2.

As described in the twentieth aspect, the extended end of the shaft connected to the inside of the grip preferably has a substantially circular cross section. In this case, it is easy to form a hole on the grip side, and workability can be improved.

[0051]

Embodiments of the present invention will be described below with reference to the accompanying drawings. [ Description of Racket Overall Structure ] As shown in FIGS. 1 and 2, the badminton racket 1 connects a frame portion F defining a racket face surface 10, a shaft portion S, and the frame portion F and the shaft portion S. Joint J
And a grip portion G fixed to an end of the shaft portion S. The frame portion F, the joint portion J, and the shaft portion S may be all integrally formed. Alternatively, the frame portion F and the shaft portion S may be formed separately, and these may be joined by the joint portion J. Here, FIGS. 1 and 2 are shared as an overall view of a badminton racket of each embodiment described later.

[ First Embodiment ] FIG. 3A shows a badminton racket according to a first embodiment of the present invention.
FIG. 3A is a sectional view taken along the line AA ′, and FIG. 3B is a sectional view taken along the line BB ′ in FIG. As shown in FIG. 3, the cross-sectional shape between AA ′ and BB ′ of the shaft portion S is substantially rhombic,
The following relationship exists between the lengths of the diagonals. a1 <b1 and a2 <b2 Further, the longer one of the diamond-shaped diagonals is arranged parallel to the racket face 10 of the frame portion F.

The rhombic cross section may be formed over the entire length of the shaft portion S, or may be formed on a part thereof. The cross-sectional shape may be substantially rhombic. That is, some R (R) may be formed at each vertex of the rhombus, and each side of the rhombus is formed of not only a straight line but also a concave arc or a convex arc which can be regarded as a substantially straight line. May be.

Further, a section taken along the line DD ', which is a section of the shaft section S on the joint J side, is formed in a substantially circular arc shape.
The cross-sectional shape may gradually change from an arc shape to a rhombic shape until the cross section is reached. These points are the same in the following embodiments. In this case, operations such as polishing and reinforcing the cross section of the shaft portion S on the joint portion J side can be easily performed, thereby improving workability.

There is a relationship of a1 <a2. That is, of the shorter diagonal lines orthogonal to the racket face 10 among the rhombic diagonal lines, the length of the diagonal line on the grip portion G side is longer than that on the frame portion F side. The diagonal lengths of the cross section of the frame portion F and the cross section of the grip portion G may be equal.
That is, a1 may be equal to a2.

Further, 4 (mm) ≦ a 1 ≦ 10 (mm), 5
(Mm) ≦ a2 ≦ 20 (mm) and a1 ≦ a2 are preferably satisfied. Specifically, a1 = 7 (mm) and a2 = 7.5 (mm) are set. The magnitude relationship between b1 and b2 does not matter. Therefore, b1 <b2 may be satisfied as shown in FIG. 3, or b1 ≧ b2.

It is preferable that the relationship of b2 / a2 ≦ 2 is satisfied. a2 = 7.5 (m
In the case of m), the relationship of b2 ≦ 2 × a2 = 15 (mm) is established, and therefore, for example, b2 = 10 (mm) is set.

Next, as shown in FIG. 4, in the section of the shaft portion S, the bending rigidity EI of the shaft section with respect to the neutral axis which takes the x-axis parallel to the racket face 10 and forms an angle θ with the x-axis is given by θ was represented as a parameter. In the figure, a curve S1 shows the bending stiffness of the shaft portion S having a roughly rhombic cross section, and a straight line S2 shows that the shaft portion S has a circular cross section and its bending stiffness is θ = 45 in the case of a roughly rhombic cross section. The case where it is set so as to match the bending stiffness EI at 135 ° and 135 ° is shown.

As is apparent from FIG. 4, the curve S1 is in the range of θ = 0 ° to 45 °,
Between 35 ° and 180 °, a straight line S2
The bending stiffness is lower than that of the straight line S2 (see the regions D1 and D3), and in the range of θ = 45 ° to 135 °, the bending stiffness is higher than the straight line S2 (see the region D2). .

Here, a swing when a badminton player hits a shuttlecock will be considered.
For example, when the player hits the shuttlecock above himself with the forehand, it is better to take back the racket and swing it behind the head, swing the racket upward from this state and hit the shuttlecock and swing it off Normally, at this time, a series of swings before and after hitting the shuttlecock are performed in a certain plane (swing plane) in the space.

When the player swings the racket up, the player swings the racket from a state in which the racket face 10 of the racket is perpendicular to the swing plane corresponds to θ = 0 °. I have. From the state where the racket face 10 is arranged at 45 ° to the swing plane, θ = 45 when the right-handed player swings the racket with the forehand and when the left-handed player swings the racket with the backhand. °.

Further, there are cases where the right-handed player swings the racket with the backhand and the case where the left-handed player swings the racket with the forehand from the state where the racket face 10 is arranged at 45 ° with the swing plane. θ = 135 ° (that is, −45 °).

As described above, within the range of θ = 0 ° to 45 °, the bending rigidity of the shaft portion having the substantially rhombic cross section according to the present embodiment is lower than that of the shaft portion having the substantially circular cross section. .

Therefore, in the range of θ = 0 ° to 45 °, the shaft portion S is more easily bent than in the case of a circular cross section. Thereby, the shaft portion S can be sufficiently bent at the time of the takeback of the right-handed player in the forehand and the backhand of the left-handed player, and as a result, the restoring force of the bending of the shaft portion S can be reduced. This can be used to increase the racket head speed.

The shorter diagonal of the diamond-shaped diagonal that is orthogonal to the racket face 10 has a longer diagonal length on the grip G side section than on the frame F side section. By controlling the amount of bending at the time of takeback, the entire shaft portion S bends smoothly, and the feeling of the racket swing is improved.

Further, the shot is such that the shuttlecock is cut obliquely or diagonally at the racket face 10 at an acute angle, for example, "cut" or "hairpin."
The case of “shot” corresponds to a range around θ = 90 °. In this range, as described above, the bending rigidity of the shaft portion having the substantially rhombic cross section according to the present embodiment is higher than that of the shaft portion having the substantially circular cross section. Therefore, θ = 90
° in the range around the shaft section S
Are less likely to bend.

Thus, it is possible to prevent the shaft portion S from being deformed in the left-right direction (the direction f in FIG. 1) upon a shot in which the shuttlecock is cut obliquely and laterally. Shake can be suppressed. As a result, the directionality of the shuttlecock after impact is improved.

Further, when following through the racket after the impact, the racket face surface 10 is rotated by 45 ° in a direction opposite to the direction of the take-back and twisted, and θ = 1.
It is equivalent to 35 °, and when the racket face 10 is swung as it is without rotating after impact, θ = 18
It corresponds to 0 °. In the range of θ = 135 ° to 180 °, as described above, the bending rigidity of the shaft portion having the substantially rhombic cross section according to the present embodiment is lower than that of the shaft portion having the substantially circular cross section.

Therefore, in the range of θ = 135 ° to 180 °, the shaft portion S is more flexible than in the case of a circular cross section. This allows the shaft portion S to be sufficiently bent even during the follow-through of the right-handed forehand and the left-handed backhand.

Alternatively, the range of θ = 135 ° to 180 ° corresponds to the respective takebacks of the backhand of the right-handed player and the forehand of the left-handed player. Therefore, in this range, the shaft portion S can be sufficiently bent at the time of the takeback of the backhand of the right-handed player and the forehand of the left-handed player, and as a result, the restoring force of the bending of the shaft portion S Can be used to increase the racket head speed.

[ Second Embodiment ] FIG. 5A shows a badminton racket according to a second embodiment of the present invention.
FIG. 3A is a sectional view taken along the line AA ′, and FIG. 3B is a sectional view taken along the line BB ′ in FIG. As shown in FIG. 5, the cross-sectional shape between AA ′ and BB ′ of the shaft portion S is substantially rhombic,
The following relationship exists between the lengths of the diagonals. a1> b1 and a2> b2 Unlike the first embodiment, the shorter one of the rhombic diagonals is arranged parallel to the racket face 10 of the frame portion F.

There is a relationship of a1 <a2. That is, of the long diagonal lines orthogonal to the racket face 10 among the rhombic diagonal lines, the length of the diagonal line on the grip portion G side is longer than that on the frame portion F side. The diagonal lengths of the cross section of the frame portion F and the cross section of the grip portion G may be equal.
That is, a1 may be equal to a2.

Further, 4 (mm) ≦ a 1 ≦ 10 (mm), 5
(Mm) ≦ a2 ≦ 20 (mm) and a1 ≦ a2 are preferably satisfied. Specifically, they are set as follows: a1 = 7 (mm), a2 = 10.0 (mm). The magnitude relationship between b1 and b2 does not matter. Therefore, b1 <b2 may be satisfied as shown in FIG. 5, or b1 ≧ b2.

It is preferable that the relationship of b2 / a2 ≧ 0.5 is satisfied. a2 = 10.0
In the case of (mm), the relationship of b2 .gtoreq.0.5.times.a2 = 5 (mm) is established, so that, for example, b2 = 7 (mm).

Next, as shown in FIG. 6, in the section of the shaft portion S, the bending rigidity EI of the shaft section with respect to the neutral axis taking the x-axis parallel to the racket face 10 and forming an angle θ with the x-axis is given by θ was represented as a parameter. In the figure, a curve S1 shows the bending stiffness of the shaft portion S having a roughly rhombic cross section, and straight lines S2 and S2 'show a higher bending stiffness and a standard bending stiffness when the shaft portion S has a circular cross section, respectively. I have. That is, the straight line S2 is represented by θ = 4
This corresponds to a circular section having a bending rigidity equal to the bending rigidity EI in the approximate rhombic section at 5 ° and 135 °, and the straight line S2 ′ is equal to the bending rigidity EI in the approximate rhombic section when θ = 90 °. This corresponds to the case of a circular section having bending rigidity.

As is clear from FIG. 6, the curve S1 is in the range of θ = 0 ° to 45 ° and the range of θ = 0 to 45 °.
Between 35 ° and 180 °, a straight line S2
(See the areas D1 and D3), and in the range of θ = 45 ° to 135 °, the bending rigidity is lower than the straight line S2 and higher than the straight line S2 '. (See area D2).

Here, as described in the first embodiment, when the player swings the racket from a state where the racket face surface 10 of the racket that the player has shaken is arranged perpendicular to the swing plane, θ = 0 °. And the racket face 10 is 45
The case where the right-handed player swings the racket with the forehand and the case where the left-handed player swings the racket with the backhand from the state where they are arranged at an angle correspond to θ = 45 °.

Also, there are cases where the right-handed player swings the racket with the backhand and the case where the left-handed player swings the racket with the forehand from the state where the racket face 10 is arranged at 45 ° with the swing plane. θ = 135 ° (that is, −45 °).

As described above, within the range of θ = 0 ° to 45 °, the shaft portion having a roughly rhombic cross section according to the present embodiment has a substantially circular cross section having a higher bending rigidity. Flexural rigidity is higher than that of the part.

Therefore, in the range of θ = 0 ° to 45 °, the shaft portion S is less likely to bend than in the case of a circular cross section. This makes it difficult for the shaft portion S to bend during the take-back of the right-handed player during the forehand and the left-handed player during the backhand.

As a result, the racket face 10 is less likely to bend in the front-rear direction (f 'direction in FIG. 2). The racket face 10 can be quickly brought to the shuttlecock when a shot is taken near the net. This makes it possible to realize a badminton racket that is particularly effective when advancing a double spray.

Further, the shot is such that the shuttlecock is cut obliquely or sharply at the racket face 10 at an acute angle, for example, "cut" or "hairpin."
The case of “shot” corresponds to a range of about θ = 90 °, but in this range, as described above, the shaft portion having the approximate rhombic cross section according to the present embodiment has the bending rigidity set to a standard value. It has a bending rigidity equivalent to or higher than that of the shaft portion having a substantially circular cross section. Therefore, θ
In the range of about 90 °, the shaft portion S does not easily bend more than in the case of a circular section having a standard bending rigidity.

Thus, when a shot that crosses the shuttlecock obliquely or laterally, the shaft S
Can be prevented from deforming in the left-right direction (f direction in FIG. 1) to some extent, and the left and right movement of the frame portion F can be suppressed.

Further, when following through the racket after the impact, the racket face surface 10 is rotated by 45 ° in the direction opposite to the direction at the time of takeback and twisted, and θ = 1.
It is equivalent to 35 °, and when the racket face 10 is swung as it is without rotating after impact, θ = 18
It corresponds to 0 °. Within the range of θ = 135 ° to 180 °, as described above, the shaft portion having a roughly rhombic cross-section according to the present embodiment is better than the shaft portion having a roughly circular cross-section set with a higher bending rigidity. High bending rigidity.

Therefore, in the range of θ = 135 ° to 180 °, the shaft portion S is less likely to bend than in the case of a circular cross section. Thus, the racket can be swung without bending the shaft portion S during the follow-through of each of the right-handed forehand and the left-handed backhand.

Alternatively, the range of θ = 135 ° to 180 ° corresponds to the takeback of the backhand of the right-handed player and the forehand of the left-handed player. Therefore, in this range, the shaft portion S is less likely to bend during the respective takebacks of the backhand of the right-handed player and the forehand of the left-handed player. This allows the shuttlecock to be hit with a small takeback and a fast action, such as "push"
The racket face 10 can be quickly brought to the shuttlecock in such a shot or a shot on the side of the net, and a badminton racket that is particularly effective when advancing a double spray can be realized.

[ Third Embodiment ] FIG. 7 shows a third embodiment of the present invention.
1C showing a badminton racket according to the embodiment of FIG.
It is -C 'sectional drawing. In the third embodiment, in the first embodiment, A-A 'and B-
The difference from the first embodiment is that the cross-sectional shape between C and C ', which is the intermediate portion between B' and C ', is shaped as shown in FIG. Therefore, in the figure, the relationship of a3 <b3 holds for each diagonal line of the rhombus, and the longer diagonal line is arranged parallel to the racket face 10 of the frame portion F.

As shown in FIG. 7, flat portions h substantially parallel to the racket face 10 are formed at the corners located at both ends of the shorter diagonal line of the rhombus. The width c3 of the plane portion h is preferably set to c3≥1.0 (mm). The axial length d (see FIG. 9) of the plane portion h is preferably set to d ≧ 3 (mm).

Next, as shown in FIG.
The x-axis is taken in parallel with the racket face surface 10 in the section taken along the line CC ′, and the bending stiffness EI of the shaft section with respect to the neutral axis forming an angle θ with the x-axis is expressed using θ as a parameter. In the figure, a curve S1 indicates the bending stiffness of the shaft section S with respect to the CC ′ cross section, and a straight line S2 indicates θ = 4.
It corresponds to the case of a circular section having a bending rigidity almost equal to the bending rigidity EI in the approximate rhombic section at 5 ° and 135 °, and the broken line curve S3 is the bending rigidity EI in the approximate rhombic section when θ = 90 °. This corresponds to the case of a hexagonal cross section having the same bending rigidity.

As is apparent from FIG. 10, the curve S1 is in the range of θ = 0 ° to 45 °
Between 135 ° and 180 °, a straight line S
2 is lower than curve S3 and higher than curve S3 (see areas D1 and D3).
In the interval of 5 °, the bending rigidity is higher than that of the straight line S2 (see the area D2).

When FIG. 10 is compared with FIG. 4 of the first embodiment, θ = 0 ° to 45 ° and θ = 135 ° to 180 °
The bending rigidity is further lower than that of the first embodiment in both sections of °, and the shaft portion S is more easily bent.

Thus, at the time of each takeback during the forehand of the right-handed player and at the time of the backhand of the left-handed player, further, at the time of the backhand of the right-handed player and at the time of the forehand of the left-handed player, At this time, the shaft S
Can be more flexed, and as a result, the racket head speed can be further increased.

In this case, the place where the plane portion h is provided becomes a so-called kick point (flexible point), and the degree of flexure of the shaft portion S can be adjusted by appropriately changing the length d, width and formation position.

For example, when the kick point is
If you bring it to the side, you can drop the shuttlecock sharply against the net of the opponent's court in an aggressive shot like smash, and if you bring the kick point to the grip G side, it will be like a high clear This makes it easy to fly the shuttlecock close to the end line during a perfect shot. In this way, a racket according to the play style can be realized.

As shown in FIG. 8, the plane portion h may be formed at one of the corners located at both ends of the shorter diagonal line of the rhombus. In FIG. 8, the same reference numerals as those in FIG. 7 indicate the same or corresponding parts.

Also in this case, the place where the plane portion h is provided becomes a so-called kick point, and the degree of bending of the shaft portion S can be adjusted by appropriately changing the length, width and formation position.

[ Fourth Embodiment ] FIG. 11A is a sectional view taken along the line AA 'of FIG. 1 showing a badminton racket according to a fourth embodiment of the present invention, and FIG. 11B is a sectional view taken along the line BB' of FIG. It is sectional drawing. As shown in FIG. 11, the cross-sectional shape between AA 'and BB' of the shaft portion S is substantially rhombic, and the following relationship exists between the lengths of the diagonal lines. a1 <b
1 and a2 <b2 Further, the shorter one of the rhombus-shaped diagonals is rotated by an angle φ from a position parallel to the racket face 10 as shown in the second embodiment.

The angle φ is set in the range of 0 ° <φ <180 °, but is preferably set in the range of 5 ° <φ <70 ° or 110 ° <φ <175 °. Most preferably, it is set in the range of 10 ° <φ <50 ° or 130 ° <φ <170 °.

There is a relationship of a1 <a2. That is, the shorter diagonal of the rhombus-shaped diagonal has a longer diagonal length on the grip portion G side section than on the frame portion F side section. The diagonal lengths of the cross section of the frame portion F and the cross section of the grip portion G may be equal. That is, a1 may be equal to a2.

Further, 4 (mm) ≦ a1 ≦ 10 (mm), 5
(Mm) ≦ a2 ≦ 20 (mm) and a1 ≦ a2 are preferably satisfied. Specifically, a1 = 7 (mm) and a2 = 7.5 (mm) are set. The magnitude relationship between b1 and b2 does not matter. Therefore, b1 <b2 may be satisfied as shown in FIG. 3, or b1 ≧ b2.

It is preferable that the relationship of b2 / a2 ≦ 2 is satisfied. a2 = 7.5 (m
In the case of m), the relationship of b2≤2.times.a2 = 15 (mm) is established, so for example, b2 = 10 (mm) is set.

In this case, the shorter one of the rhombus-shaped diagonals is rotated by an angle φ from a position parallel to the racket face 10 so that φ is smaller.
Is 0 ° to 90 °, the following operation and effect can be obtained.

That is, the bending rigidity in the direction in which the shaft portion S tends to bend (the diagonal lines b1 and b2) during takeback during a forehand of a right-handed player and backhand of a left-handed player is high. The shaft portion S cannot flex sufficiently.
For this reason, especially with a so-called "push" shot or a shot near the net, where the shuttlecock hits the shuttlecock quickly by holding the racket face face quickly to the net side, the takeback is small and the movement is fast with the racket face side. It is easier to hit as many shots. In addition, this makes it possible to realize a badminton racket that is particularly effective when advancing a double spray.

Also, when the right-handed player performs a backhand and when the left-handed player performs a forehand, the bending rigidity in the direction in which the shaft portion S tends to bend (the diagonal directions a1 and a2) is low. At times, the shaft portion S can be sufficiently bent. Thereby, the racket speed can be increased by the restoring force of the bending of the shaft portion S.

[ Fifth Embodiment ] FIG. 12A is a sectional view taken along the line AA 'of FIG. 1 showing a badminton racket according to a fifth embodiment of the present invention, and FIG. 12B is a sectional view taken along the line BB' of FIG. It is sectional drawing. As shown in FIG. 12, the cross-sectional shape between AA 'and BB' of the shaft portion S is substantially rhombic, and the following relationship exists between the lengths of the diagonal lines. a1 <b
1 and a2 <b2 Further, the longer one of the rhombus-shaped diagonals is rotated by an angle φ from a position parallel to the racket face 10 as shown in the first embodiment.

This angle φ is set in the range of 0 ° <φ <180 °, but is preferably set in the range of 5 ° <φ <70 ° or 110 ° <φ <175 °. Most preferably, it is set in the range of 10 ° <φ <50 ° or 130 ° <φ <170 °. Note that the same relationship as that of the fourth embodiment is established between a1, a2, b1, and b2.

In this case, the longer one of the rhombus-shaped diagonals is rotated by an angle φ from a position parallel to the racket face 10 so that φ
Is 0 ° to 90 °, the following operational effects are obtained.

That is, the bending rigidity in the direction in which the shaft portion S tends to bend (diagonal lines a1 and a2) during the takeback in the forehand of the right-handed player and in the backhand of the left-handed player is low. The shaft portion S can be sufficiently bent. Thereby, the racket speed can be increased by the restoring force of the bending of the shaft portion S.

[0109] Further, in the case of the back-hand of the right-handed player and in the case of the forehand of the left-handed player, the bending rigidity in the direction in which the shaft portion S tends to bend (the diagonal lines b1 and b2) is high. The shaft portion S cannot be sufficiently bent at the time of backing.
Therefore, quickly bring the racket face to the shuttlecock near the net and hit the shuttlecock,
Like a so-called “push” shot, it is easy to hit a shot with a small takeback and a quick movement of the racket face. In addition, this makes it possible to realize a racket that is particularly effective when advancing a double spray.

Here, in the fourth and fifth embodiments, φ is set in the above range for the following reason. FIG. 13 is a diagram illustrating the magnitude and direction of the bending moment acting on the shaft portion S of the racket from the take-back to the follow-through through the impact through the impact. Here, a case where a right-handed person swings a racket with forehand is taken as an example.

As shown in FIG. 13, the direction of the bending moment acting on the shaft portion S during takeback is at an angle α with the racket face surface 10, and the direction of the bending moment acting on the shaft portion S during follow-through is It can be seen that an angle β is formed with the face surface 10.

Therefore, using a plurality of subjects, various shots (smash,
Drive, high clear, etc.) were repeatedly performed and the values of these angles α and β were measured. The angles α and β were found to fall within the ranges of 20 ° <α <85 ° and 20 ° <β <85 °. found.

Further, when the analysis is performed focusing on data of intermediate and advanced users, the most preferable values of the angles α and β of the racket 1 are 40 ° <α <80 ° and 40 ° <β <80 °. found.

Therefore, in the range of the value of φ in the present invention, there is a deviation of 90 ° with respect to the directions α and β of the bending moment acting on the shaft portion at the angle of the neutral axis due to the bending rigidity of the shaft cross section. Therefore, φ = 90 ° −α and φ = 90 ° −β, and the value of φ is within the range of 5 ° <| φ | <70 °, and most preferably within the range of 10 ° <| φ | <50 °. , At the time of takeback, shaft part S
By setting the bending stiffness in the direction in which the wire is going to be bent to be high or low, the above-described effects can be obtained.

[0115]

As described above in detail, according to the badminton racket of the present invention, at least a part of the shaft has a substantially rhombic cross section perpendicular to the axis thereof. There is an effect that can be improved. Also, there is an effect that a badminton racket according to a play style can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a badminton racket according to the present invention.

FIG. 2 is a schematic side view of a badminton racket according to the present invention.

3A is a sectional view taken along line AA ′ of FIG. 1 showing a badminton racket according to the first embodiment of the present invention, and FIG. 3B is a sectional view taken along line BB ′ of FIG.

FIG. 4 is a diagram showing a relationship between a position of a neutral axis of a cross section of a badminton racket according to the first embodiment of the present invention and bending rigidity.

5A is a sectional view taken along the line AA ′ of FIG. 1 showing a badminton racket according to the second embodiment of the present invention, and FIG. 5B is a sectional view taken along the line BB ′ of FIG.

FIG. 6 is a diagram showing a relationship between a position of a neutral axis of a cross section of a badminton racket according to a second embodiment of the present invention and bending rigidity.

FIG. 7 is a cross-sectional view taken along the line CC ′ of FIG. 1, illustrating a badminton racket according to a third embodiment of the present invention;

FIG. 8 is a sectional view taken along the line CC ′ of FIG. 1 showing a badminton racket according to a modification of the third embodiment of the present invention.

9 is a sectional view taken along line IX-IX in FIG. 7;

FIG. 10 is a view showing a relationship between a position of a neutral axis of a cross section of a badminton racket according to a third embodiment of the present invention and bending rigidity.

FIG. 11A is a sectional view taken along the line AA ′ of FIG. 1 showing a badminton racket according to a fourth embodiment of the present invention, and FIG.
Is a sectional view taken along the line BB 'in FIG.

FIG. 12A is a sectional view taken along the line AA ′ of FIG. 1 showing a badminton racket according to a fifth embodiment of the present invention, and FIG.
Is a sectional view taken along the line BB 'in FIG.

FIG. 13 is a view for explaining a state in which the magnitude and direction of a bending moment acting on a shaft portion of a badminton racket are changed, and a right-handed player follows a racket from a take-back through an impact with a forehand. It is the figure which looked at the history up to the through from the racket frame side.

[Explanation of symbols]

 1 Badminton racket 10 Racket face surface F Frame part S Shaft part G Grip part h Flat part

Claims (20)

[Claims] 1. A badminton racket comprising a frame defining a racket face surface, a grip, and a shaft connecting the frame and the grip, wherein at least a part of the shaft has a cross section perpendicular to an axis thereof. A badminton racket characterized by a roughly rhombic shape. 2. The badminton racket according to claim 1, wherein one diagonal of the rhombus is arranged to be parallel to the racket face surface. 3. The badminton racket according to claim 2, wherein the longer diagonal line of the rhombus is arranged so as to be parallel to the racket face surface. 4. The badminton racket according to claim 2, wherein the shorter diagonal of the rhombus is arranged to be parallel to the racket face surface. 5. The badminton racket according to claim 3, wherein a length of a diagonal of the diamond-shaped diagonal orthogonal to the racket face surface is equal between a frame-side cross-section and a grip-side cross-section. A badminton racket which is longer on the grip side section than on the frame side section. 6. The badminton racket according to claim 5, wherein a cross-sectional shape of the shaft at a frame connecting portion side is substantially circular. 7. The badminton racket according to claim 5, wherein a diagonal length a1 orthogonal to the racket face surface in the cross section on the frame side is 4 to 10 mm and orthogonal to the racket face surface in the cross section on the grip side. A badminton racket having a diagonal length a2 of 5 to 20 mm and a1 ≤ a2. 8. The badminton racket according to claim 7, wherein a cross-sectional shape of the shaft on the frame connecting portion side is substantially circular and an outer diameter is a1. 9. The badminton racket according to claim 7, wherein a length of a diagonal line parallel to the racket face surface in the grip-side section is b2, 1 <b2 / a2 ≦ 2 or 0.5 ≦. A badminton racket, wherein b2 / a2 <1. 10. The badminton racket according to claim 3, wherein at least a part of each of the corners located at both ends of a shorter diagonal of the rhombus in at least a part of an axial direction of the shaft portion having a rhombus-shaped cross section. Either one has a plane portion substantially parallel to the racket face surface,
A badminton racket characterized by the following. 11. The badminton racket according to claim 1, wherein one of diagonal lines of the rhombus is rotated within a range of 0 ° to 180 ° with respect to the racket face surface. racket. 12. The badminton racket according to claim 11, wherein one of the diagonal lines of the rhombus is 5 ° to 70 ° or 110 ° to 175 from a position parallel to the racket face surface.
A badminton racket, which is arranged to be rotated within the range of °. 13. The badminton racket according to claim 12, wherein a shorter one of the diamond-shaped diagonals is within a range of 5 ° to 70 ° or 110 ° to 175 ° from a position parallel to the racket face surface. A badminton racket, which is arranged by rotating the racket. 14. The badminton racket according to claim 12, wherein a longer one of the diamond-shaped diagonals is within a range of 5 ° to 70 ° or 110 ° to 175 ° from a position parallel to the racket face surface. A badminton racket, which is arranged by rotating the racket. 15. The badminton racket according to claim 13, wherein a shorter one of the rhombic diagonals is equal in a frame-side cross section and a grip-side cross section, or in the frame side. A badminton racket, which is longer on the grip side section than on the section. 16. The badminton racket according to claim 15, wherein a cross-sectional shape of the shaft at a frame connecting portion side is substantially circular. 17. The badminton racket according to claim 15 or 16, wherein a shorter diagonal length a1 of the diagonal lines in the frame-side cross section is 4 to 10 mm, and a shorter diagonal line in the grip-side cross section. Diagonal length a2 is 5
A badminton racket having a size of ２０20 mm and a1 ≦ a2. 18. The badminton racket according to claim 17, wherein a cross-sectional shape of the shaft on the side of the frame connecting portion is substantially circular and the outer diameter is a1. 19. The badminton racket according to claim 17, wherein 1 <b2 / a2 ≦ 2, where b2 is the longer diagonal of the diagonals on the grip side section. Badminton racket. 20. The badminton racket according to claim 1, wherein an extended end of the shaft, which is connected to an inside of the grip, has a substantially circular cross section. A badminton racket that features.