JP7326978B2 - Specification determination method of badminton racket and analysis method of shaft behavior - Google Patents

Description

The present invention relates to a badminton racket specification determination method. In particular, the present invention relates to a method of determining characteristics of a shaft that is part of a racquet.

A badminton racket has a frame, strings and a shaft. A player shoots a shuttle with a racket. The shaft deforms when shot. The deformation behavior of the shaft influences the behavior of the shuttle. Shaft characteristics determine shot quality.

Japanese Unexamined Patent Application Publication No. 2012-147846 discloses a shaft having moderate flexibility and moderate rigidity.

Japanese Patent Application Laid-Open No. 2012-147846

In a game of badminton, players make different types of shots. For example, the player makes shots such as smashes, lobs, and cuts.

There are players who prefer powerful shots. Some players prefer controlled shots.

In a badminton doubles game, a pair is formed between a forward player and a rearward player. Shots that are mainly required for front-line players and shots that are mainly required for rear-line players are different.

There is a demand for shafts with specifications suitable for the shots that players prefer. There is also a demand for shafts that are suitable for shots that are frequently used by players.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of determining specifications by which a badminton racket suitable for a specific player or a specific shot can be obtained.

A badminton racket specification determination method according to the present invention includes:
(A) analyzing how the shaft bends on a shot; and (B) determining characteristics of the target shaft based on the analysis results of step (A).

Preferably, in step (A), how the shaft bends is determined based on the amount of bending of the shaft.

Preferably, in step (A), the degree of bending is determined based on the maximum amount of bending of the shaft.

Preferably, in step (A), how the shaft bends is determined based on the amount of bending of the shaft in the in-plane direction and the amount of bending of the shaft in the out-of-plane direction.

Preferably, in step (A), how the shaft bends is determined based on the maximum amount of bending of the shaft in the in-plane direction and the maximum amount of bending of the shaft in the out-of-plane direction.

Preferably, in step (A), the degree of bending is determined by the ratio of the amount of bending of the shaft in the in-plane direction to the amount of bending of the shaft in the out-of-plane direction.

Preferably, the property determined in step (B) is the stiffness of the shaft.

Preferably, the property determined in step (B) is the stiffness distribution of the shaft.

Preferably, the properties determined in step (B) are the stiffness of the shaft in the in-plane direction and the stiffness of the shaft in the out-of-plane direction.

Preferably, the properties determined in step (B) are the shaft stiffness distribution in the in-plane direction and the shaft stiffness distribution in the out-of-plane direction.

According to another aspect, a method for manufacturing a badminton racket according to the present invention comprises:
(A) a step of analyzing how the shaft bends on shots;
(B) determining the properties of the target shaft based on the results of the analysis in step (A) above; and (C) attaching a frame and grip to the shaft having the properties determined in step (B) above. including.

According to still another aspect, the method for analyzing the shaft behavior of a badminton racket according to the present invention comprises:
(A) a step of measuring the amount of bending of the shaft in the in-plane direction and the amount of bending of the shaft in the out-of-plane direction in the shot; and (B) the amount of bending of the shaft in the in-plane direction and the out-of-plane direction. and the amount of bending of the shaft.

A suitable badminton racket for a particular player can be obtained by the determination method according to the present invention. A badminton racket suitable for a particular shot can be obtained by the determination method according to the present invention.

FIG. 1 is a front view showing a badminton racket obtained by a determining method according to one embodiment of the present invention. 2 is a right side view of the racket of FIG. 1; FIG. FIG. 3 is a graph showing the results of a three-point bending stiffness test of a standard racket shaft. FIG. 4 is a graph showing the measurement results of the bending amount of the shaft of the standard racket during smash. 5 is a front view showing the racket of FIG. 1 in a curved state; FIG. 6 is a right side view showing the racket of FIG. 1 in a curved state; FIG. FIG. 7 is a graph showing the results of a 3-point bending stiffness test of shafts of other rackets. FIG. 8 is a graph showing the measurement results of the bending amount of the standard racket shaft during lobing. FIG. 9 is a graph showing the results of a 3-point bending stiffness test on the shaft of still another racket. FIG. 10 is a graph showing the measurement results of the bending amount of the shaft of the standard racket when cut. FIG. 11 is a graph showing the results of a 3-point bending stiffness test on the shaft of still another racket. FIG. 12 is a flow chart showing a specification determination method according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

A badminton racket 2 is shown in Figures 1 and 2 . This racket 2 has a shaft 4 , a frame 6 , a grip 8 and strings 10 . 1 and 2, arrow X represents the width direction, arrow Y represents the axial direction, and arrow Z represents the thickness direction.

Shaft 4 is hollow. The shaft 4 is made of fiber reinforced resin. In this fiber-reinforced resin, a large number of reinforcing fibers are impregnated with a base resin.

Thermosetting resins such as epoxy resins, pismaleimide resins, polyimides and phenolic resins; thermoplastic resins are exemplified. A particularly suitable resin for the shaft 4 is an epoxy resin.

Carbon fibers, metal fibers, glass fibers, and aramid fibers are examples of reinforcing fibers for the shaft 4 . A particularly suitable fiber for shaft 4 is carbon fiber. A plurality of types of fibers may be used in combination.

The frame 6 is annular and hollow. The frame 6 is made of fiber reinforced resin. A resin similar to the base resin of the shaft 4 can be used as the base resin of the fiber-reinforced resin. As the reinforcing fibers of this fiber-reinforced resin, the same resin as the reinforcing fibers of the shaft 4 can be used. A frame 6 is rigidly connected to the front end of the shaft 4 .

The grip 8 has a hole (not shown) extending in the axial direction (Y direction). The vicinity of the rear end of the shaft 4 is inserted into this hole. The inner peripheral surface of the hole and the outer peripheral surface of the shaft 4 are joined with an adhesive.

A string 10 is strung on the frame 6 . The string 10 is stretched along the width direction X and the axial direction Y. As shown in FIG. A portion of the string 10 extending along the width direction X is referred to as a cross string. A portion of the string 10 that extends along the axial direction Y is referred to as a longitudinal string. A plurality of cross strings and a plurality of longitudinal strings form a face 12 (see FIG. 2). Face 12 generally lies along the XY plane.

In the design method according to the present invention, first, a standard racket is prepared. This standard racket has a shaft. FIG. 3 shows the results of a three-point bending stiffness test for this shaft. In this embodiment, there are four bending stiffness measurement points. This shaft has a substantially flat stiffness distribution from the vicinity of the grip to the front end. Shafts with non-flat stiffness distributions may be employed in standard racquets. Various specifications of shafts may be employed in standard rackets. A standard racket may be used by the player on a daily basis.

[smash]
This standard racket was used by one player, and the bending of the shaft during smashing was photographed with an infrared camera. From the obtained images, the bending amount of the shaft during shots was measured. In this embodiment, the bending amount of the shaft from the start of the shot to the end of the impact with the shuttle was measured. The results are shown in FIG. In FIG. 4, the solid line indicates the amount of bending in the in-plane direction, and the dotted line indicates the amount of bending in the out-of-plane direction. In this embodiment, the amount of bending in the in-plane direction is the moving distance of the front end of the shaft in the X direction, which is indicated by an arrow Lx in FIG. In this embodiment, the amount of bending in the out-of-plane direction is the moving distance of the front end of the shaft in the Z direction, which is indicated by an arrow Lz in FIG. The bending amounts in the in-plane direction and the out-of-plane direction may be measured at a predetermined position of the shaft other than the front end.

The behavior of the shaft is analyzed based on the amount of bending in the in-plane direction and the amount of bending in the out-of-plane direction. From FIG. 4, it can be seen that the shaft bends more in the in-plane direction and more in the out-of-plane direction in the player's smash. A ratio R1 between the maximum amount of bending in the in-plane direction and the maximum amount of bending in the out-of-plane direction is 0.76.

You let this player use another racket. The stiffness distribution of the shaft of this racket is shown in FIG. This shaft has a stiffness distribution that descends forward. The behavior of the shuttle after the smash using this racket was photographed with a high-speed camera. From the images obtained, we measured the speed of the shuttle as it crossed the net. The results are as follows.

Standard racket (stiffness distribution: flat)
Average speed: 23.9m/s
Maximum speed: 26.6m/s
Minimum speed: 21.0m/s
Variation: 5.6m/s
Other rackets (rigidity distribution: front down)
Average speed: 24.5m/s
Maximum speed: 25.7m/s
Minimum speed: 23.9m/s
Variation: 1.8m/s

In a smash using a racket including a shaft having a forward-downward stiffness distribution, the average speed is high and the variation in speed is small. From this result, it can be seen that a racket including a shaft having a forward-downward stiffness distribution is suitable for this player's smash.

Shots other than smashes by this player can cause the shaft to bend greatly both in the in-plane direction and in the out-of-plane direction. For example, the ratio R1 can be between 1/2 and 2/1. It is presumed that a shaft having a forward-sloping stiffness distribution is suitable for such shots.

Shots by other players can also cause the shaft to flex more in both the in-plane and out-of-plane directions. For example, the ratio R1 can be greater than or equal to 1/2 and less than 2/1. It is presumed that a shaft having a forward-sloping stiffness distribution is suitable for such shots.

It is presumed that a shaft having a forward-downward stiffness distribution is suitable for a player who frequently makes shots in which the shaft bends greatly both in the in-plane direction and the out-of-plane direction. It is presumed that a shaft having a forward-downward stiffness distribution is also suitable for a player who emphasizes shots in which the shaft bends in both the in-plane direction and the out-of-plane direction.

[Robbing]
One player was allowed to use the aforementioned standard racket, and the bending of the shaft during lobbing was photographed with an infrared camera. From the obtained images, the bending amount of the shaft from the start of the shot to the end of impact with the shuttle was measured. The results are shown in FIG. In FIG. 8, the solid line indicates the amount of bending in the in-plane direction, and the dotted line indicates the amount of bending in the out-of-plane direction.

As is clear from FIG. 8, in this player's lobbing, the shaft bends less in the in-plane direction and more in the out-of-plane direction. A ratio R1 between the maximum amount of bending in the in-plane direction and the maximum amount of bending in the out-of-plane direction is 0.14.

You let this player use another racket. The stiffness distribution of the shaft of this racket is shown in FIG. This shaft has a downwardly convex stiffness distribution. The behavior of the shuttle after lobbing with this racket was photographed with a high-speed camera. From the images obtained, the height of the shuttle when over the net was measured. The results are as follows.

Standard racket (stiffness distribution: flat)
Average height: 1.88m
Maximum height: 2.20m
Minimum height: 1.63m
Variation: 0.57m
Other rackets (rigidity distribution: downward convex)
Average height: 1.85m
Maximum height: 1.97m
Minimum height: 1.80m
Variation: 0.17m

In robbing using a racket including a shaft having a downwardly convex stiffness distribution, the shuttle height variation is small. From this result, it can be seen that a racket including a shaft having a downwardly convex stiffness distribution is suitable for this player's lobbing.

Shots other than lobbing by this player can also bend the shaft largely in the out-of-plane direction. For example, the ratio R1 can be less than 1/2. It is presumed that a shaft having a downwardly convex stiffness distribution is suitable for such shots.

Shots by other players can also cause the shaft to flex largely in the out-of-plane direction. For example, the ratio R1 can be less than 1/2. It is presumed that a shaft having a downwardly convex stiffness distribution is suitable for such shots.

It is presumed that a shaft having a downwardly convex stiffness distribution is suitable for players who frequently use shots in which the shaft bends largely in the out-of-plane direction. It is presumed that a shaft having a downwardly convex stiffness distribution is also suitable for players who emphasize shots in which the shaft bends largely in the out-of-plane direction.

[cut]
One player was allowed to use the aforementioned standard racket, and the bending of the shaft at the time of cutting was photographed with an infrared camera. From the obtained images, the bending amount of the shaft from the start of the shot to the end of impact with the shuttle was measured. The results are shown in FIG. In FIG. 10, the solid line indicates the amount of bending in the in-plane direction, and the dotted line indicates the amount of bending in the out-of-plane direction.

As is clear from FIG. 10, in this player's cut, the shaft bends less in the out-of-plane direction and more in the in-plane direction. A ratio R1 between the maximum amount of bending in the in-plane direction and the maximum amount of bending in the out-of-plane direction is 2.47.

You let this player use another racket. The stiffness distribution of the shaft of this racket is shown in FIG. This shaft has an upwardly convex stiffness distribution. The behavior of the shuttle after cutting with this racket was photographed with a high-speed camera. From the images obtained, the height of the shuttle when over the net was measured. The results are as follows.

Standard racket (stiffness distribution: flat)
Average height: 0.58m
Maximum height: 0.72m
Minimum height: 0.36m
Variation: 0.36m
Other rackets (stiffness distribution: upward convex)
Average height: 0.50m
Maximum height: 0.55m
Minimum height: 0.45m
Variation: 0.10m

In a cut using a racket including a shaft having an upwardly convex stiffness distribution, variations in shuttle height are small. From this result, it can be seen that a racket including a shaft having a convex stiffness distribution is suitable for this player's cut.

Even shots other than cuts by this player can bend the shaft largely in the in-plane direction. For example, the ratio R1 can be 2/1 or greater. It is presumed that a shaft having an upwardly convex stiffness distribution is suitable for such shots.

Shots by other players can also cause the shaft to bend largely in the in-plane direction. For example, the ratio R1 can be 2/1 or greater. It is presumed that a shaft having an upwardly convex stiffness distribution is suitable for such shots.

It is presumed that a shaft having an upwardly convex stiffness distribution is suitable for players who frequently use shots in which the shaft bends largely in the in-plane direction. It is presumed that a shaft having an upwardly convex stiffness distribution is also suitable for players who emphasize shots in which the shaft bends mainly in the in-plane direction.

[Determination of racket specifications]
FIG. 12 is a flow chart showing a specification determination method according to an embodiment of the present invention. In this determination method, first, the bending of the shaft is photographed in a shot with a standard racket (STEP 1). Typically the picture is taken with an infrared camera. Motion control photography is typically used. Shooting is performed in shots that are frequently used by the player or shots that are emphasized by the player.

Based on the captured image, the bending of the shaft is analyzed (STEP 2). Preferably, the maximum deflection of the shaft from the start of the shot to the end of impact with the shuttle is measured. Preferably, the amount of bending in the in-plane direction and the amount of bending in the out-of-plane direction are measured. Preferably, a ratio R1 between the maximum amount of bending in the in-plane direction and the maximum amount of bending in the out-of-plane direction is calculated.

Based on the obtained bending of the shaft, the characteristics of the target shaft are determined (STEP 3). Examples of properties include length, thickness, weight, mass distribution, stiffness, stiffness distribution, and the like. Typically, a target shaft stiffness distribution is determined. The stiffness of the shaft in the in-plane direction and the stiffness of the shaft in the out-of-plane direction may be determined. A stiffness distribution of the shaft in the in-plane direction and a stiffness distribution of the shaft in the out-of-plane direction may be determined.

An example of criteria for determining the target shaft stiffness distribution based on the ratio R1 between the maximum amount of bending in the in-plane direction and the maximum amount of bending in the out-of-plane direction is shown below.
Ratio R1 is less than 1/2: Select a downwardly convex stiffness distribution Ratio R1 is 1/2 or more and less than 2/1: Select a forwardly downward stiffness distribution Ratio R1 is 2/1 or more: Select an upwardly convex stiffness distribution selection

A racket fitted with a shaft having the determined characteristics is selected from ready-made products (STEP 4). Thus, the specifications of the badminton racket are determined. The racket selected is suitable for the player concerned. Players can use this racket to make highly accurate shots.

A new racket may be manufactured by attaching a frame and grip to an existing shaft having the determined characteristics. In other words, the present invention has the following aspects.
(A) a step of analyzing how the shaft bends on shots;
(B) determining the properties of the target shaft based on the results of the analysis in step (A) above; and (C) attaching a frame and grip to the shaft having the properties determined in step (B) above. A method of manufacturing a badminton racket, comprising:

A new shaft having the determined characteristics may be manufactured.

A useful application of the specification determination method according to the present invention is customization. According to the invention, the optimum badminton racket for each player can be determined.

The specification determination method according to the present invention can also contribute to enrichment of the product line-up. for example,
(1) A badminton racket suitable for players who prefer powerful shots (2) A badminton racket suitable for players who prefer controlled shots (3) A badminton racket suitable for doubles frontline players (4) A badminton racket suitable for doubles backline players (5) A badminton racket suitable for players who place importance on serving (6) A badminton racket suitable for players who place importance on smashing (7) A badminton racket suitable for players who place importance on receiving, etc. are commercially available.

A badminton racket suitable for an individual player can be selected by the specification determination method according to the present invention.

2 Badminton Racket 4 Shaft 6 Frame 8 Grip 10 String 12 Face

Claims (10)

(A) The step of analyzing the bending of the shaft by measuring the amount of bending of the shaft in the in-plane direction and the amount of bending of the shaft in the out-of-plane direction in the shot, and (B) the above step ( A method for determining specifications of a badminton racket, including the step of determining characteristics of a target shaft based on the results of the analysis of A). 2. The specification determining method according to claim 1, wherein, in step (A), how the shaft bends is determined based on the maximum amount of bending of the shaft in the in-plane direction and the maximum amount of bending of the shaft in the out-of-plane direction. 3. The specification determining method according to claim 1, wherein in step (A), the degree of bending is determined based on the ratio of the amount of bending of the shaft in the in-plane direction and the amount of bending of the shaft in the out-of-plane direction. 4. The specification determining method according to any one of claims 1 to 3 , wherein the characteristic determined in step (B) is the stiffness of the shaft. 4. The specification determining method according to any one of claims 1 to 3, wherein the characteristic determined in step (B) is the stiffness distribution of the shaft. 4. The specification determining method according to any one of claims 1 to 3, wherein the characteristics determined in step (B) are the stiffness of the shaft in the in-plane direction and the stiffness of the shaft in the out-of-plane direction. 4. The specification determining method according to any one of claims 1 to 3, wherein the characteristics determined in step (B) are the shaft stiffness distribution in the in-plane direction and the shaft stiffness distribution in the out-of-plane direction. 8. The shaft according to any one of claims 1 to 7, wherein in step (A), the amount of bending of the shaft in the in-plane direction and the amount of bending of the shaft in the out-of-plane direction are measured at predetermined positions of the shaft. Specification determination method described. (A) a step of analyzing the bending of the shaft by measuring the amount of bending of the shaft in the in-plane direction and the amount of bending of the shaft in the out-of-plane direction on a shot;
(B) determining the properties of the target shaft based on the results of the analysis in step (A) above; and (C) attaching a frame and grip to the shaft having the properties determined in step (B) above. A method of manufacturing a badminton racket, comprising: (A) a step of measuring the amount of bending of the shaft in the in-plane direction and the amount of bending of the shaft in the out-of-plane direction in the shot; and (B) the amount of bending of the shaft in the in-plane direction and the out-of-plane direction. A method of analyzing the shaft behavior of a badminton racket, comprising the step of comparing the amount of bending of the shaft of the badminton racket.

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