JP7465934B1 - Shuttlecock - Google Patents

Abstract

[Problem] To provide a shuttlecock that has flight performance equivalent to that of a natural shuttlecock and whose shaft is less likely to break. [Solution] Shuttlecock 1 comprises a base body 2 and artificial feather 3. Artificial feather 3 includes feather portion 5 and shaft 6. In a cross section perpendicular to the first direction at a position 10 mm from the base end of shaft 6, the polar moment of area of shaft 6 is equal to or greater than 2.48 mm4 and equal to or less than 3.08 mm4. In a cross section perpendicular to the first direction at a position 40 mm from the base end of shaft 6, the polar moment of area of shaft 6 is equal to or greater than 1.01 mm4 and equal to or less than 1.25 mm4. [Selected Figure] Figure 1

Description

The present invention relates to a shuttlecock.

Conventionally, there are two types of badminton shuttlecocks: those that use waterfowl feathers (natural shuttlecocks) and those that use artificially manufactured feathers made of nylon resin or the like (artificial shuttlecocks). There is a demand for artificial shuttlecocks with flight performance equivalent to that of natural shuttlecocks. For example, Japanese Patent No. 6161381 (Patent Document 1) describes an artificial shuttlecock with flight performance equivalent to that of a natural shuttlecock.

Patent No. 6161381

The artificial shuttlecock described in the above publication had a tendency for the shuttlecock shaft to break when struck by the racket frame.

The present invention was made in consideration of the above problems, and its purpose is to provide a shuttlecock that has flight performance equivalent to that of a natural shuttlecock and whose shaft is less likely to break.

The shuttlecock of the present invention includes a base body and an artificial feather. The artificial feather is connected to the base body. The artificial feather includes a feather portion and a shaft. The shaft is connected to the feather portion. The shaft includes a web extending in a first direction in which the shaft extends, a first flange, and a second flange. The web extends in a second direction perpendicular to the first direction. The first flange protrudes from one end of the web in the second direction in a third direction perpendicular to the second direction. The second flange protrudes from the other end of the web in the second direction in the third direction. In a cross section perpendicular to the first direction at a position 10 mm from the base end of the shaft, the polar moment of area of the shaft is 2.48 mm4 ^or more and 3.08 ^mm4 or less. In a cross section perpendicular to the first direction at a position 40 mm from the base end of the shaft, the polar moment of area of the shaft is 1.01 mm4 ^or more and 1.25 ^mm4 or less. The shaft is made of block polypropylene.

The present invention makes it possible to provide a shuttlecock that has flight performance equivalent to that of a natural shuttlecock and whose shaft is less likely to break.

FIG. 1 is a schematic front view of a shuttlecock in one embodiment of the present invention. FIG. 1 is a schematic plan view of a shuttlecock in one embodiment of the present invention. FIG. 1 is a schematic perspective view of an artificial feather for a shuttlecock in one embodiment of the present invention. FIG. 1 is a schematic side view of an artificial feather for a shuttlecock in one embodiment of the present invention. 5 is a cross-sectional view taken along line VV in FIG. 4. 4A and 4B are a view taken along an arrow and a cross-sectional view of the tip of a shaft of a shuttlecock in Comparative Example 1. 3A and 3B are an arrow view and a cross-sectional view of the tip of the shaft of the shuttlecock in Example 1. 11A and 11B are a view taken along an arrow and a cross-sectional view of the tip of a shaft of a shuttlecock in Example 2.

The following describes an embodiment of the present invention with reference to the drawings. Note that the same or corresponding parts in the following drawings are given the same reference numbers and their description will not be repeated.

First, the configuration of the shuttlecock 1 in one embodiment of the present invention will be described with reference to Figures 1 and 2.

Figure 1 is a schematic front view of shuttlecock 1 in this embodiment. Figure 2 is a schematic plan view of shuttlecock 1 in this embodiment. Shuttlecock (badminton shuttlecock) 1 comprises a base body 2 and a number of artificial feathers (artificial feathers for shuttlecocks) 3. In this embodiment, shuttlecock 1 further comprises a fixing string-like member 4.

The base body 2 is configured in a hemispherical shape. The base body 2 has a fixing surface portion 2a configured with a nearly flat surface. The artificial feathers 3 are connected to the base body 2. The artificial feathers 3 are arranged in a circular ring shape along the outer periphery of the fixing surface portion 2a of the base body 2. The artificial feathers 3 are also fixed to each other by a fixing string member 4. The artificial feathers 3 are arranged such that the distance between them increases the further they are from the base body 2. In other words, the artificial feathers 3 are arranged such that the inner diameter of the cylinder formed by the artificial feathers 3 increases the further they are from the base body 2. A protrusion 3a is provided on part of the inside of the artificial feathers 3.

Next, the configuration of the artificial feathers 3 that make up the shuttlecock 1 in one embodiment of the present invention will be described in detail with reference to Figures 3 to 5.

Figure 3 is a schematic perspective view of artificial feather 3 of shuttlecock 1 in this embodiment. Referring to Figure 3, artificial feather 3 constituting shuttlecock 1 shown in Figures 1 and 2 includes feather portion 5 and shaft 6 connected to feather portion 5. Shaft 6 includes feather shaft portion 7 arranged to protrude from feather portion 5, fixed shaft portion 8 connected to feather portion 5 at approximately the center of feather portion 5, and fixed portion 9 arranged on the opposite side of fixed shaft portion 8 with respect to feather shaft portion 7. Fixed portion 9 is inserted into base body 2 from fixing surface portion 2a of base body 2 shown in Figure 2. Feather shaft portion 7, fixed shaft portion 8 and fixed portion 9 are arranged to extend in the same line and constitute one continuous shaft 6.

Figure 4 is a schematic side view of artificial feather 3 of shuttlecock 1 in the present embodiment. Figure 5 is a cross-sectional view taken along line V-V in Figure 4. With reference to Figures 4 and 5, shaft 6 includes web 10, first flange 11, and second flange 12. Web length L1 is the length of web 10 in second direction D2. Flange length L2 is the average of the length from one end to the other end of first flange 11 and the length from one end to the other end of second flange 12 in third direction D3. Web thickness T is the thickness of web 10 in third direction D3.

The web 10, the first flange 11, and the second flange 12 extend in a first direction D1 in which the shaft 6 extends. In other words, the first direction D1 is the axial length direction. Note that the shaft 6 has a curvature from the base end to the tip, and therefore the first direction D1 has a curvature. The web 10 extends in a second direction D2 perpendicular to the first direction D1. The web 10 is provided continuously in the first direction D1 over the entire fixed shaft portion 8 and the blade shaft portion 7.

The first flange 11 protrudes from one end of the web 10 in the second direction D2 in a third direction D3 perpendicular to the second direction D2. One end of the web 10 is disposed inside the shaft 6. The first flange 11 is disposed inside the shaft 6. The first flange 11 is disposed so as to be perpendicular to the web 10. The first flange 11 is provided continuously over the entire fixed shaft portion 8 and the blade shaft portion 7 in the first direction D1.

The second flange 12 protrudes from the other end of the web 10 in the second direction D2 in the third direction D3. The other end of the web 10 is disposed outside the shaft 6. The second flange 12 is disposed outside the shaft 6. The second flange 12 is disposed so as to be perpendicular to the web 10. The second flange 12 is provided continuously over the entire fixed shaft portion 8 and the blade shaft portion 7 in the first direction D1.

In a cross section perpendicular to the first direction D1 at a position 10 mm from the base end of the shaft 6, the second polar moment of area of the shaft 6 is 2.48 ^mm4 or more and 3.08 ^mm4 or less. The second polar moment of area Ip of the shaft 6 is the sum of the second moment of area Ix of the shaft 6 about the x axis and the second moment of area Iy of the shaft 6 about the y axis (Ip = Ix + Iy). For example, the shaft 6 may be embedded in the base body 2 (see FIG. 1) from the base end to a position 10 mm or more and 13 mm or less. In a cross section perpendicular to the first direction D1 at a position 40 mm from the base end of the shaft 6, the second polar moment of area of the shaft 6 is 1.01 mm4 ^or more and 1.25 ^mm4 or less.

In a cross section perpendicular to the first direction D1 at a position 10 mm from the base end of the shaft 6, the cross-sectional area is 2.74 ^mm2 or greater and 2.92 ^mm2 or less. In a cross section perpendicular to the first direction D1 at a position 40 mm from the base end of the shaft 6, the cross-sectional area is 2.10 ^mm2 or greater and ^2.29 mm2 or less.

In a cross section perpendicular to the first direction D1 at a position 10 mm from the base end of the shaft 6, the length of each of the first flange 11 and the second flange 12 in the third direction D3 is greater than the length of the web 10 in the second direction D2.

A round shape is provided at the connection portion between the web 10 and each of the first flange 11 and the second flange 12. In a cross section perpendicular to the first direction D1 at a position 10 mm from the base end of the shaft 6, the radius of curvature of the round shape of the connection portion is 0.7 mm.

The shaft 6 is made of block polypropylene. That is, the material of the shaft 6 is block polypropylene. It is preferable that the shaft 6 does not contain reinforcing fibers.

The tensile product of shaft 6 is 1800 MPa·% or more and 4400 MPa·% or less. The tensile product (MPa·%) is the product of the tensile strength (MPa) and the breaking elongation (%). The tensile product is used to estimate the breaking energy of a material.

The first flange 11 and the second flange 12 may have equal lengths in the first direction D1. The first flange 11 and the second flange 12 may have equal lengths in the third direction D3. The web 10 is disposed at the center of the first flange 11 and the second flange 12 in the third direction D3.

The shaft 6 has an inner surface 6a at the inner end of the first flange 11 and an outer surface 6b at the outer end of the second flange 12. The shaft 6 has a first side surface 6c connecting one end of the inner surface 6a and the outer surface 6b, and a second side surface 6d connecting the other end of the inner surface 6a and the outer surface 6b. Both the first side surface 6c and the second side surface 6d have recesses 13 extending in the first direction D1, which is the extension direction of the shaft 6. The recesses 13 are formed on the side surface of the web 10, the inner side surface of the first flange 11, and the inner side surface of the second flange 12. The recesses 13 are located in the center of the direction in which the inner surface 6a and the outer surface 6b face each other. A space is provided in the shaft 6 by the recesses 13. The shape of a cross section perpendicular to the first direction D1, which is the extension direction of the shaft 6, is an I-shape.

Next, we will explain the effects of the shuttlecock 1 in this embodiment.

The torsional rigidity of the shaft 6 of the shuttlecock 1 is the product of the transverse elastic modulus (shear elastic modulus) G of the shaft 6 and the polar moment of area Ip of the shaft 6. As the polar moment of area Ip increases, the torsional rigidity increases. As the torsional rigidity increases, the shaft 6 becomes less likely to break. Therefore, by increasing the polar moment of area Ip, the shaft 6 can be made less likely to break. In addition, because the tips of the shaft 6 are less likely to overlap, it is possible to prevent the stacking order of the feather portions 5 from being swapped (intertwined). If such intertwining of the feather portions 5 occurs, the shuttlecock 1 will no longer rotate normally when struck by the racket, and its flight characteristics will deteriorate drastically.

According to shuttlecock 1 in the present embodiment, in a cross section perpendicular to first direction D1 at a position 10 mm from the base end of shaft 6, the polar moment of area Ip of shaft 6 is 2.48 ^mm4 or more and 3.08 ^mm4 or less. In a cross section perpendicular to first direction D1 at a position 40 mm from the base end of shaft 6, the polar moment of area Ip of shaft 6 is 1.01 ^mm4 or more and 1.25 ^mm4 or less. For this reason, shuttlecock 1 in the present embodiment can have a larger polar moment of area Ip than the comparative example described later. Therefore, the torsional rigidity of shaft 6 can be increased. Therefore, shaft 6 can be made less likely to break. Furthermore, because the tip portions of shaft 6 are less likely to overlap, it is possible to suppress the stacking order of blade portions 5 from being interchanged (intertwined).

The cross section perpendicular to the first direction D1, which is the extension direction of the shaft 6, has an I-shape. The flight performance of the shuttlecock 1 is greatly affected by the bending rigidity obtained by multiplying the moment of inertia of the shaft 6 and the elastic modulus of the material. Since the I-shape cross section has a large moment of inertia, it is possible to increase the moment of inertia of the shaft 6. This makes it possible to increase the bending rigidity of the shaft 6. As a result, it is possible to provide flight performance equivalent to that of a natural shuttlecock.

According to shuttlecock 1 in the present embodiment, the cross-sectional area in a cross section perpendicular to first direction D1 at a position 10 mm from the base end of shaft 6 is 2.74 ^mm2 or more and 2.92 ^mm2 or less. The cross-sectional area in a cross section perpendicular to first direction D1 at a position 40 mm from the base end of shaft 6 is 2.10 ^mm2 or more and ^2.29 mm2 or less. Therefore, shuttlecock 1 in the present embodiment can have a larger cross-sectional area than the comparative example described later. This makes it possible to increase the polar moment of area Ip. Therefore, the torsional rigidity of shaft 6 can be increased. Furthermore, because the tip portions of shaft 6 are less likely to overlap, it is possible to suppress the stacking order of blade portions 5 from being interchanged (intertwined).

According to the shuttlecock 1 of this embodiment, in a cross section perpendicular to the first direction D1 at a position 10 mm from the base end of the shaft 6, the length of each of the first flange 11 and the second flange 12 in the third direction D3 is greater than the length of the web 10 in the second direction D2. Therefore, the cross-sectional area of the shuttlecock 1 of this embodiment can be made larger than that of the comparative example described later. This allows the second polar moment of area Ip to be increased. This allows the torsional rigidity of the shaft 6 to be increased. This makes it possible to make the shaft 6 less likely to break. In addition, because the tip portions of the shaft 6 are less likely to overlap, it is possible to prevent the stacking order of the vane portions 5 from being changed (intertwined).

According to the shuttlecock 1 of this embodiment, the radius of curvature of the round shape of the connection part is 0.7 mm in a cross section perpendicular to the first direction D1 at a position 10 mm from the base end of the shaft 6. Therefore, in the shuttlecock 1 of this embodiment, the radius of curvature of the round shape of the connection part can be made larger in a cross section perpendicular to the first direction D1 at a position 10 mm from the base end of the shaft 6 than in the comparative example described later. Therefore, it is possible to prevent the force acting on the shaft 6 from concentrating on the connection part in a cross section perpendicular to the first direction D1 at a position 10 mm from the base end of the shaft 6. This makes it possible to make the shaft 6 less likely to break.

According to the shuttlecock 1 in this embodiment, the shaft 6 is made of block polypropylene. Block polypropylene has better impact resistance than homopolypropylene and random polypropylene. This makes it possible to make the shaft 6 less likely to break. Block polypropylene also has the property of being excellent in moldability. This makes it possible to make the thickness of the web 10 thinner. This makes it possible to lengthen the length of the web 10, the first flange 11, and the second flange 12, and therefore to increase the moment of inertia. Block polypropylene is also lightweight, so the cross-sectional area can be increased. This makes it possible to increase the moment of inertia of the shaft 6. It is also preferable that the shaft 6 does not contain reinforcing fibers. If the shaft 6 contains reinforcing fibers, the breaking elongation will be reduced, and the tensile product will be reduced, making the shaft 6 more likely to break. Since the shaft 6 does not contain reinforcing fibers, it is possible to make the shaft 6 less likely to break.

In the shuttlecock 1 of this embodiment, the tensile product of the shaft 6 is 1800 MPa·% or more and 4400 MPa·% or less. This makes it possible to make the shaft 6 less likely to break.

The examples of the present invention will be explained in comparison with the comparative examples. Examples 1 to 4 are examples of the present invention. Comparative examples 1 to 4 are comparative examples to the examples of the present invention.

The shapes of the shuttlecock shafts in Comparative Example 1 and Examples 1 and 2 will be described with reference to Figures 6 to 8. Figure 6 is an arrow view and a cross-sectional view of the tip of the shuttlecock shaft in Comparative Example 1. Figure 7 is an arrow view and a cross-sectional view of the tip of the shuttlecock shaft in Example 1. Figure 8 is an arrow view and a cross-sectional view of the tip of the shuttlecock shaft in Example 2. Figures 6 to 8 show cross-sectional views at positions 10 mm, 30 mm, 40 mm, and 60 mm from the base end of the shaft in the extension direction of the shaft. The arrow view of the tip is an arrow view of the shaft viewed from a direction perpendicular to the tip surface of the shaft.

Table 1 shows the moment of inertia Ix at each cross section in Comparative Example 1, Example 1, and Example 2. Table 2 shows the moment of inertia Iy at each cross section in Comparative Example 1, Example 1, and Example 2. Table 3 shows the moment of inertia Ip at each cross section in Comparative Example 1, Example 1, and Example 2.

Referring to Table 3, in a section perpendicular to the first direction at a position 10 mm from the base end of the shaft (a section perpendicular to the shaft in the axial direction), the polar moment of area Ip of Example 1 and Example 2 is larger than the polar moment of area Ip of Comparative Example 1. Also, in a section perpendicular to the first direction at a position 40 mm from the base end of the shaft (a section perpendicular to the shaft in the axial direction), the polar moment of area Ip of Example 1 and Example 2 is larger than the polar moment of area Ip of Comparative Example 1. From Example 1 and Example 2, in a section perpendicular to the first direction at a position 10 mm from the base end of the shaft, the polar moment of area of the shaft of the Example of the present invention is 2.48 ^mm4 or more and 3.08 ^mm4 or less. From Example 1 and Example 2, in a section perpendicular to the first direction at a position 40 mm from the base end of the shaft, the polar moment of area of the shaft of the Example of the present invention is 1.01 ^mm4 or more and 1.25 ^mm4 or less.

Table 4 shows the cross-sectional areas at each cross section in Comparative Example 1, Example 1, and Example 2.

Referring to Table 4, in a cross section perpendicular to the first direction at a position 10 mm from the base end of the shaft, the cross-sectional areas of Example 1 and Example 2 are larger than that of Comparative Example 1. Also, in a cross section perpendicular to the first direction at a position 40 mm from the base end of the shaft, the cross-sectional areas of Example 1 and Example 2 are larger than that of Comparative Example 1. From Example 1 and Example 2, in a cross section perpendicular to the first direction at a position 10 mm from the base end of the shaft, the cross-sectional area of the shaft of the Example of the present invention is 2.74 mm ² or more and 2.92 mm ² or less. From Example 1 and Example 2, in a cross section perpendicular to the first direction at a position 40 mm from the base end of the shaft, the cross-sectional area of the shaft of the Example of the present invention is 2.10 mm ² or more and 2.29 mm ² or less.

Referring to Tables 5 to 7, the web thickness, web length, and flange length of the shuttlecock shafts in Comparative Example 1 and Examples 1 and 2 are explained.

Table 5 shows the web thickness at each cross section in Comparative Example 1, Example 1, and Example 2. Table 6 shows the web length at each cross section in Comparative Example 1, Example 1, and Example 2. Table 7 shows the average flange length at each cross section in Comparative Example 1, Example 1, and Example 2.

Next, we will explain the test in which the shuttlecock was hit with the racket frame.

Example 3, Example 4, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are all configured in the same shape as Example 1. Example 3, Example 4, Comparative Example 2, Comparative Example 3, and Comparative Example 4 have different shaft materials. Example 3 is block polypropylene and has a tensile product of 1800 MPa.%. Example 4 is block polypropylene and has a tensile product of 4400 MPa.%. Comparative Example 2 is block polypropylene and has a tensile product of 750 MPa.%. Comparative Example 3 is random polypropylene and has a tensile product of 6500 MPa.%. Comparative Example 4 is long fiber cellulose reinforced polypropylene and has a tensile product of 584 MPa.%.

The test method was as follows. With the artificial feathers on both sides of the shuttlecock supported and the shuttlecock suspended, an arm-type shuttle launching machine was used to strike the shuttle with the racket so that the tip of the racket frame hit the feather shaft part between the feather part of the shaft and the base body. The arm-type shuttle launching machine was set so that the speed of the tip of the racket frame was 200 km/h. There were five samples of each.

Table 8 shows the test results. In Table 8, the number of breaks and bends is shown. A break is a state in which performance is extremely deteriorated if the same condition occurs during use. A bend is a state in which performance is not impaired if the same condition occurs during use. Examples 3 and 4 have fewer breaks and bends than Comparative Examples 2, 3, and 4. From Examples 3 and 4, the tensile product of the shafts of the examples of the present invention is 1800 MPa·% or more and 4400 MPa·% or less.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

1 shuttlecock, 2 base body, 3 artificial feather, 4 fixing string-like member, 5 feather portion, 6 shaft, 7 feather shaft portion, 8 fixed shaft portion, 9 fixing portion, 10 web, 11 first flange, 12 second flange, 13 recess, D1 first direction, D2 second direction, D3 third direction.

Claims (5)

A base body,
a plurality of artificial feathers connected to the base body;
The artificial feather includes a feather portion and a shaft connected to the feather portion,
The shaft includes a web, a first flange, and a second flange extending in a first direction along which the shaft extends;
The web extends in a second direction perpendicular to the first direction;
the first flange projects from one end of the web in the second direction in a third direction perpendicular to the second direction,
the second flange projects in the third direction from the other end of the web in the second direction;
In a cross section perpendicular to the first direction at a position 10 mm from the base end of the shaft, the second polar moment of area of the shaft is 2.48 mm4 ^or more and 3.08 ^mm4 or less,
In a cross section perpendicular to the first direction at a position 40 mm from the base end of the shaft, the second polar moment of area of the shaft is 1.01 mm4 ^or more and 1.25 ^mm4 or less ;
The shuttlecock, wherein the shaft is made of block polypropylene . A cross-sectional area of the shaft perpendicular to the first direction at a position 10 mm from the base end is 2.74 ^mm2 or more and 2.92 ^mm2 or less,
The shuttlecock according to claim 1, wherein a cross-sectional area of a cross section perpendicular to the first direction at a position 40 mm from the base end of the shaft is equal to or greater than 2.10 ^mm2 and equal to or less than ^2.29 mm2. The shuttlecock of claim 2, wherein in a cross section perpendicular to the first direction at a position 10 mm from the base end of the shaft, the length of each of the first flange and the second flange in the third direction is greater than the length of the web in the second direction. A round shape is provided at each of connection portions between the web and the first flange and between the web and the second flange,
The shuttlecock according to claim 1, wherein a radius of curvature of the round shape of the connection portion is 0.7 mm in a cross section perpendicular to the first direction at a position 10 mm from the base end of the shaft. The shuttlecock according to claim 1 , wherein the shaft has a tensile product of 1800 MPa·% or more and 4400 MPa·% or less.

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