TWI839570B - Badminton racket - Google Patents

Abstract

A badminton racket is provided, which can prevent the shaft from being broken at the bent position when the shaft is bent. The racket (10) of the present invention comprises: a frame (13) extending in an annular shape, a grip (11), and a shaft (12) connecting the frame and the grip. The shaft comprises: an innermost layer (21) and a shaft-forming layer (22) stacked on the outer side of the innermost layer. The shaft is formed by winding a plurality of sheets (S) impregnated with resin in a fibrous reinforcing material in a stacked manner. The plurality of sheets include: an innermost sheet (S01) forming an innermost layer, and an axis-forming sheet (S11 to S13) whose reinforcing material is made of carbon fiber and forms an axis-forming layer. The reinforcing material in the innermost sheet is made of ultra-high-density polymer fiber.

Description

Badminton racket

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

Badminton is played by a player swinging a racket and hitting a shuttlecock. For example, as described in Patent Document 1, a badminton racket has a shaft that connects a grip and a ring-shaped frame and extends in a straight line. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 6-71001

[The problem the invention is trying to solve]

Badminton rackets may be damaged in the shaft during preparation before playing, or due to collision with the racket of a doubles partner or the floor during playing. If such damage occurs, the shaft may be bent and broken during playing, and the frame side may separate from the broken position and fly in an unexpected direction.

The present invention is made in view of this point, and its purpose is to provide a badminton racket that can prevent the shaft from being broken at the bent position when the shaft is bent. [Technical means for solving the problem]

The badminton racket of the present invention comprises: a frame extending in an annular shape, a grip, and a cylindrical shaft connecting the frame and the grip, wherein the shaft comprises: an innermost layer and at least one shaft-forming layer stacked on the outer side of the innermost layer, which is formed by overlapping and winding a plurality of sheets in which a fiber-like reinforcing material is impregnated with a resin, wherein the plurality of sheets comprises: an innermost sheet forming the innermost layer, and a shaft-forming sheet in which the reinforcing material is made of carbon fiber and forms the shaft-forming layer, and the reinforcing material in the innermost sheet is made of ultra-high-density polymer fiber.

According to this structure, since the innermost reinforcing material is ultra-high density polymer fiber, the adhesion between the ultra-high density polymer fiber and the resin forming the innermost layer can be weakened. Therefore, even if the shaft is accidentally bent and separated, the ultra-high density polymer fiber can be peeled off from the resin forming the innermost layer in the areas on both sides of the bent position. As a result, the peeled ultra-high density polymer fiber will not be cut, but can be kept connected on both sides of the bent position, so that the frame side can be prevented from being separated from the bent position and flying out.

In the present invention, the ultra-high density polymer fiber is preferably arranged in the direction of the extension of the shaft. According to this structure, the ultra-high density polymer fiber can easily maintain a connected state from both sides of the bent position of the shaft.

In the present invention, the innermost sheet is preferably arranged in an area spanning more than half of the circumference of the shaft. With this structure, when the shaft is bent, the ultra-high density polymer fiber can be peeled off from the resin forming the innermost layer, and the connection state can be maintained on both sides of the bent position. In addition, the innermost layer can be formed in about half of the circumference of the shaft, and the area where the innermost sheet is arranged can be reduced, so that the amount of sheets impregnated with resin in the ultra-high density polymer fiber can be suppressed.

In the present invention, the aforementioned ultra-high density polymer fiber is preferably polyethylene fiber or polyester fiber. According to this structure, the material cost can be suppressed and the strength of the ultra-high density polymer fiber can be ensured, and the axis can be well avoided from being broken. [Effect of the invention]

According to the present invention, when the shaft is bent, it can be prevented from being broken at the bent position.

Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a front view of a badminton racket of the embodiment. In addition, in the following figures, for the convenience of explanation, some structures are omitted.

As shown in FIG. 1 , a badminton racket (hereinafter referred to as a “racket”) 10 includes a grip 11 held by a player, a shaft 12 connected to the grip 11 at one end and extending in a straight line, and a frame 13 connected to the other end of the shaft 12 and forming an elliptical ring. Strings 14 are stretched inside the frame 13, and the strings 14 form a hitting surface 15 for hitting a badminton.

The grip 11 and the shaft 12 are connected in a state where the shaft 12 is inserted (buried) into the grip 11 by a predetermined length and fixed by adhesion or the like.

The frame 13 is formed of a hollow body with a predetermined thickness, and its cross-sectional shape can be various shapes such as circular, elliptical, or square. The frame 13 is formed by internal pressure molding generated by the expansion of a medium such as air. In the racket 10, the frame 13 and the shaft 12 are connected by a T-shaped joint 16 embedded therein.

FIG. 2 is a schematic three-dimensional view showing a section of a shaft used in the badminton racket. As shown in FIG. 2, the shaft 12 is a hollow cylindrical shape, and is formed by stacking a plurality of layers in the radial direction. The shaft 12 includes: an innermost layer 21 located at the innermost side, and a plurality of (three layers in this embodiment) shaft-forming layers 22 stacked on the outer side of the innermost layer 21. The structure of each layer 21, 22 forming the shaft 12 is as described in the following description of the manufacturing method of the shaft 12.

FIG. 3 is an explanatory diagram of the manufacturing method of the shaft. As shown in FIG. 3, in the manufacturing of the shaft 12, first, a plurality of sheets S are prepared in which a fiber-like reinforcing material is impregnated with a resin. In this embodiment, the plurality of sheets S are formed by impregnating a fiber-like reinforcing material with a thermosetting resin such as epoxy or vinyl resin and semi-hardening the thermosetting resin.

Here, among the plurality of sheets S forming the shaft 12, the innermost sheet S01 forming the innermost layer 21 uses ultra-high density polymer fiber as a reinforcing material. Here, ultra-high density polymer fiber refers to a synthetic resin with a molecular weight of 1.5 million or more, and specifically, polyethylene fiber or polyester fiber can be exemplified. The arrangement direction of the reinforcing material (ultra-high density polymer fiber) in the innermost sheet S01 is set to be parallel to the extension direction of the shaft 12.

In order to form a plurality of axis-forming layers 22, three sheets of a first axis-forming sheet S11, a second axis-forming sheet S12, and a third axis-forming sheet S13 are used from the innermost sheet S01 toward the outside. The reinforcing material of each axis-forming sheet S11 to S13 is carbon fiber. The arrangement direction of the reinforcing material in the first axis-forming sheet S11 is set to point in a direction of 45° with respect to the extension direction of the axis 12. The arrangement direction of the reinforcing material in the second axis-forming sheet S12 is also set to point in a direction of 45° with respect to the extension direction of the axis 12, but is set to a direction different from the arrangement direction of the reinforcing material in the first axis-forming sheet S11 by 90°. The arrangement direction of the reinforcing material in the third axis forming sheet S13 is set to be the extending direction of the axis 12 .

Moreover, the above-mentioned axis-forming sheets S11 to S13 are only examples. For example, the axis-forming sheets S11 to S13 may be increased or decreased in accordance with the increase or decrease of the axis-forming layer 22, and the arrangement direction of each reinforcing material may be appropriately selected from the above-mentioned directions or directions inclined at a predetermined angle from the directions.

After preparing the plurality of sheets S as described above, in order to form the shaft 12, the plurality of sheets S are stacked concentrically on the mandrel and wound into a cylindrical shape. At this time, as shown in FIG. 3, the innermost sheet S01 is arranged at the innermost side. In this embodiment, the innermost sheet S01 is arranged in the entire area of the circumferential direction of the cylinder forming the shaft 12. After the winding as described above, after heating and hardening to form a formed body, by extracting the mandrel, the manufacture of the cylindrical shaft 12 having the innermost layer 21 and the plurality of shaft forming layers 22 shown in FIG. 2 can be completed.

Here, in the racket 10 of the above embodiment, the shaft 12 is bent, and the following description is made with reference to FIG. 4A. FIG. 4B is a cross-sectional view of the shaft in a normal state, and FIG. 4A is a cross-sectional view of the shaft in an example after the shaft is bent. In FIG. 4A and FIG. 4B, the shaft forming layer 22 of multiple layers is simplified as a single layer.

The shaft 12 is bent from the position indicated by the dotted line in FIG. 4A to the bent state as shown in FIG. 4B. In the state of FIG. 4B, the upper side of the shaft 12 in the same figure becomes the mountain side, and the lower side in the same figure becomes the valley side. The shaft-forming layer 22 is made of a hard material by using a fiber-reinforced resin with carbon fiber as a reinforcing material, so the shaft 12 is separated from the shaft-forming layer 22 at the bent position in the bent state.

However, only a part of the reinforcing material (ultra-high-density polymer fiber, denoted by the symbol "21a" in FIG. 4B) in the innermost layer 21 of the shaft 12 is cut at the bending position, and the other part is not cut at the bending position. Specifically, the reinforcing material (ultra-high-density polymer fiber) 21a of the innermost layer 21 included in the valley side of the bending position is cut in a manner that follows the bending and cutting of the shaft-forming layer 22. On the other hand, the reinforcing material (ultra-high-density polymer fiber) 21a of the innermost layer 21 included in the mountain side of the bending position is peeled off from the thermosetting resin forming the innermost layer 21 in the areas on both sides of the bending position. The reason for such peeling is that since the reinforcing material 21a of the innermost layer 21 is ultra-high-density polymer fiber, the adhesion with the thermosetting resin forming the innermost layer 21 is weakened.

Thus, the reinforcing material (ultra-high density polymer fiber) 21a in the peeled innermost layer 21 will not be cut, and the connection state can be maintained from both sides of the bent position. When playing badminton, because the player holds the grip 11, it can be prevented that the frame 13 and the part of the shaft 12 on the opposite side of the grip 11 on both sides of the bent position are separated and fly away.

Furthermore, the present invention is not limited to the above-mentioned embodiments, and various modifications can be implemented. In the above-mentioned embodiments, the size, shape, direction, etc. shown in the attached drawings are not limited, and can be appropriately modified within the scope of the effect of the present invention. Other modifications can be appropriately implemented as long as they do not deviate from the scope of the purpose of the present invention.

In the above-mentioned embodiment, the arrangement direction of the ultra-high density polymer fibers in the innermost layer 21 is set to be parallel to the extension direction of the shaft 12, but it can also be changed to a direction inclined with respect to the extension direction. However, if the arrangement direction of the ultra-high density polymer fibers is parallel to the extension direction of the shaft 12, it is advantageous because both sides of the bent position of the shaft 12 can be easily maintained in a connected state by the ultra-high density polymer fibers in the innermost layer 21.

In the above embodiment, the innermost layer 21 is formed over the entire area of the shaft 12 in the circumferential direction, but it may be arranged across half a circumference or more than half a circumference. When the shaft 12 is bent, as described above, the reinforcing material of the innermost layer 21 is connected in the half circumference area on the mountain side, so if the innermost layer 21 has more than half a circumference in the circumferential direction, the portion where the reinforcing material of the innermost layer 21 is connected can be left. In this case, the area where the innermost layer sheet S01 is arranged is reduced, and the amount used can be suppressed.

Furthermore, in the sheet S forming the axis-forming layer 22, in addition to carbon fiber, reinforcing materials such as glass fiber and ceramic fiber may be used instead of or in combination with carbon fiber. [Industrial Applicability]

The present invention relates to a badminton racket which can prevent the shaft from being broken due to bending.

10: racket 11: grip 12: shaft 13: frame 14: string 15: hitting surface 16: joint 21: innermost layer 21a: reinforcement material 22: shaft forming layer S: sheet S01: innermost sheet S11: 1st shaft forming sheet S12: 2nd shaft forming sheet S13: 3rd shaft forming sheet

[Figure 1] A front view of a badminton racket of an embodiment of the present invention. [Figure 2] A schematic three-dimensional view showing a section of a portion of a shaft used in the badminton racket. [Figure 3] An explanatory view of a method for manufacturing the shaft. [Figure 4] Figure 4A is an explanatory cross-sectional view of the shaft in a normal state, and Figure 4B is an explanatory cross-sectional view showing an example of the shaft being bent.

12: Axis

21: Innermost layer

21a: Reinforcement material

22: Axonal layer

Claims (4)

A badminton racket comprises: a frame extending in an annular shape, a grip, and a cylindrical shaft connecting the frame and the grip, wherein the shaft comprises: an innermost layer and at least one shaft-forming layer stacked on the outer side of the innermost layer, formed by stacking and winding a plurality of sheets in which a fiber-like reinforcing material is impregnated with a resin, wherein the plurality of sheets comprises: an innermost sheet forming the innermost layer, and a shaft-forming sheet in which the reinforcing material is made of carbon fiber and forms the shaft-forming layer, and the reinforcing material in the innermost sheet is made of ultra-high-density polymer fiber. As in claim 1, the badminton racket, wherein the ultra-high density polymer fiber is arranged in the extension direction of the shaft. A badminton racket as claimed in claim 1 or 2, wherein the innermost sheet is arranged in an area spanning more than half of the circumference of the axis. A badminton racket as claimed in claim 1 or 2, wherein the ultra-high density polymer fiber is polyethylene fiber or polyester fiber.

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