EP4098334A1 - Federballschläger - Google Patents

Federballschläger Download PDF

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Publication number
EP4098334A1
EP4098334A1 EP21757626.3A EP21757626A EP4098334A1 EP 4098334 A1 EP4098334 A1 EP 4098334A1 EP 21757626 A EP21757626 A EP 21757626A EP 4098334 A1 EP4098334 A1 EP 4098334A1
Authority
EP
European Patent Office
Prior art keywords
shaft
flexural rigidity
measurement point
sheet
fiber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21757626.3A
Other languages
English (en)
French (fr)
Other versions
EP4098334A4 (de
Inventor
Wataru Kimizuka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Rubber Industries Ltd
Original Assignee
Sumitomo Rubber Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Rubber Industries Ltd filed Critical Sumitomo Rubber Industries Ltd
Publication of EP4098334A1 publication Critical patent/EP4098334A1/de
Publication of EP4098334A4 publication Critical patent/EP4098334A4/de
Pending legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B60/00—Details or accessories of golf clubs, bats, rackets or the like
    • A63B60/0081—Substantially flexible shafts; Hinged shafts
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B49/00—Stringed rackets, e.g. for tennis
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B2102/00—Application of clubs, bats, rackets or the like to the sporting activity ; particular sports involving the use of balls and clubs, bats, rackets, or the like
    • A63B2102/04—Badminton
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B2209/00—Characteristics of used materials
    • A63B2209/02—Characteristics of used materials with reinforcing fibres, e.g. carbon, polyamide fibres
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B2209/00—Characteristics of used materials
    • A63B2209/02—Characteristics of used materials with reinforcing fibres, e.g. carbon, polyamide fibres
    • A63B2209/023—Long, oriented fibres, e.g. wound filaments, woven fabrics, mats
    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B60/00—Details or accessories of golf clubs, bats, rackets or the like
    • A63B60/42—Devices for measuring, verifying, correcting or customising the inherent characteristics of golf clubs, bats, rackets or the like, e.g. measuring the maximum torque a batting shaft can withstand

Definitions

  • the present invention relates to a badminton racket.
  • the present invention relates to improvements to the shaft of the racket.
  • a badminton racket includes a frame, a string, and a shaft. The player shots a shuttlecock with the racket. The shaft is deformed upon the shot.
  • the player performs various types of shots.
  • the player performs shots such as lob, smash, cut, and clear.
  • the lob is often hit from the vicinity of the net in the court of the player.
  • the lob is a shot aimed at sending the shuttlecock deep to the back of the court of the opponent player.
  • the shuttlecock flies along a high trajectory in the lob.
  • the player is required to have the skill to allow the shuttlecock to fly at an intended height.
  • the player wants to stabilize the trajectory of the shuttlecock in the lob.
  • the shaft In the lob, the shaft is deflected mainly in the out-of-plane direction.
  • the player wants to stabilize the trajectory of the shuttlecock also for shots which are other than the lob and in which the shaft is deflected in the out-of-plane direction.
  • An object of the present invention is to provide a badminton racket suitable for shots in which the shaft of the racket is deflected mainly in the out-of-plane direction.
  • a badminton racket according to the present invention includes:
  • a ratio (EI(2)/EI(1)) of the flexural rigidity value EI(2) to the flexural rigidity value EI(1) is not greater than 0.95.
  • a ratio (EI(3)/EI(2)) of the flexural rigidity value EI(3) to the flexural rigidity value EI(2) is not greater than 0.90.
  • a difference (EI(2) - EI(1)) between the flexural rigidity value EI(2) and the flexural rigidity value EI(1) is not greater than -0.30 Nm 2 .
  • a difference (EI(3) - EI(2)) between the flexural rigidity value EI(3) and the flexural rigidity value EI(2) is not greater than -0.5 Nm 2 .
  • the shaft may have a hollow structure.
  • an inner diameter of the shaft is substantially constant from the first measurement point to the third measurement point.
  • an outer diameter of the shaft is substantially constant from the first measurement point to the third measurement point.
  • a ratio (W1/W2) of a weight W1 of the shaft in a zone from the first measurement point to the second measurement point to a weight W2 of the shaft in a zone from the second measurement point to the third measurement point is not less than 0.95 and not greater than 1.05.
  • the shaft includes a fiber-reinforced layer.
  • the fiber-reinforced layer is located in a zone including the first measurement point and not including the second and third measurement points in an axial direction of the shaft.
  • the fiber-reinforced layer includes a plurality of reinforcing fibers oriented substantially in the axial direction.
  • the shaft includes another fiber-reinforced layer.
  • the fiber-reinforced layer is located in a zone including the first and second measurement points and not including the third measurement point in the axial direction of the shaft.
  • the fiber-reinforced layer includes a plurality of reinforcing fibers oriented substantially in the axial direction.
  • a player using the badminton racket according to the present invention can easily perform shots in which the shaft is deflected mainly in the out-of-plane direction.
  • the racket can contribute to winning badminton games.
  • FIGS. 1 and 2 show a badminton racket 2.
  • the racket 2 includes a shaft 4, a frame 6, a grip 8, and a string 10.
  • the arrow X represents the width direction
  • the arrow Y represents the axial direction
  • the arrow Z represents the thickness direction.
  • the shaft 4 includes a butt portion 12, a middle portion 14, and a tip portion 16.
  • the shaft 4 further includes a butt end 18 and a tip end 20.
  • the shaft 4 is hollow.
  • the shaft 4 is formed from a fiber-reinforced resin.
  • the fiber-reinforced resin includes a resin matrix and a large number of reinforcing fibers.
  • the shaft 4 includes a plurality of fiber-reinforced layers (which will be described in detail later).
  • Examples of the base resin of the shaft 4 include: thermosetting resins such as epoxy resin, bismaleimide resin, polyimide, and phenol resin; and thermoplastic resins such as polyether ether ketone, polyethersulfone, polyetherimide, polyphenylene sulfide, polyamide, and polypropylene.
  • Epoxy resin is particularly suitable as the resin of the shaft 4.
  • Examples of the reinforcing fibers of the shaft 4 include carbon fibers, metal fibers, glass fibers, and aramid fibers. Carbon fibers are particularly suitable as the fibers of the shaft 4. Different kinds of fibers may be used in combination.
  • the frame 6 is ring-shaped and hollow.
  • the frame 6 is formed from a fiber-reinforced resin. Any of the resins as mentioned for the base resin of the shaft 4 can be used as the base resin of the fiber-reinforced resin. Any of the fibers as mentioned for the reinforcing fibers of the shaft 4 can be used as the reinforcing fibers of the fiber-reinforced resin.
  • the frame 6 is firmly joined to the tip end 20 of the shaft 4.
  • the grip 8 includes a hole 21 extending in the axial direction (Y direction).
  • the butt end 18 and its vicinity of the shaft 4 are inserted into the hole 21.
  • the inner peripheral surface of the hole 21 and the outer peripheral surface of the shaft 4 are bonded with an adhesive.
  • the string 10 is strung on the frame 6.
  • the string 10 is placed along the width direction X and the axial direction Y.
  • the portions of the string 10 that extend along the width direction X are referred to as transverse threads 22.
  • the portions of the string 10 that extend along the axial direction Y are referred to as longitudinal threads 24.
  • the plurality of transverse threads 22 and the plurality of longitudinal threads 24 form a face 26.
  • the face 26 extends generally along the X-Y plane.
  • the reference sign L represents the length of the exposed portion of the shaft 4.
  • the length L is usually not less than 150 mm and not greater than 210 mm.
  • FIG. 3 is an enlarged cross-sectional view showing a part of the shaft 4 of the racket 2 of FIG. 1 .
  • FIG. 4 is an enlarged cross-sectional view taken along the line IV-IV of FIG. 3 .
  • the shaft 4 is hollow.
  • the cross-section of the shaft 4 is circular. In other words, the shaft 4 is in the shape of a cylindrical tube.
  • the arrow Di represents the inner diameter of the shaft 4.
  • the inner diameter Di is typically not less than 3 mm and not greater than 10 mm.
  • the arrow Do represents the outer diameter of the shaft 4.
  • the outer diameter Do is typically not less than 5 mm and not greater than 15 mm.
  • the shaft 4 is formed from a fiber-reinforced resin.
  • the shaft 4 can be produced by a sheet winding method. In the sheet winding method, a plurality of prepregs are wound on a mandrel. Each prepreg includes a plurality of fibers and a matrix resin. The matrix resin is uncured.
  • FIG. 5 is a developed view showing a prepreg arrangement for the shaft 4 of the racket 2 of FIG. 1 .
  • the prepreg arrangement includes eight prepregs (sheets). Specifically, the prepreg arrangement includes a first sheet S1, a second sheet S2, a third sheet S3, a fourth sheet S4, a fifth sheet S5, a sixth sheet S6, a seventh sheet S7, and an eighth sheet S8.
  • a plurality of fiber-reinforced layers are formed from the prepregs by a method described later.
  • a first fiber-reinforced layer is formed from the first sheet S1
  • a second fiber-reinforced layer is formed from the second sheet S2
  • a third fiber-reinforced layer is formed from the third sheet S3
  • a fourth fiber-reinforced layer is formed from the fourth sheet S4
  • a fifth fiber-reinforced layer is formed from the fifth sheet S5
  • a sixth fiber-reinforced layer is formed from the sixth sheet S6
  • a seventh fiber-reinforced layer is formed from the seventh sheet S7
  • an eighth fiber-reinforced layer is formed from the eighth sheet S8.
  • the left-right direction in FIG. 5 is the axial direction of the shaft 4.
  • the locations of the butt end 18 and tip end 20 are indicated by arrows.
  • the locations of three measurement points P1, P2, and P3 described later are also indicated by arrows.
  • the reduction scale in the left-right direction (axial direction) is not equal to the reduction scale in the up-down direction.
  • the first sheet S1 extends over the entirety of the shaft 4.
  • the first sheet S1 is generally rectangular.
  • the first sheet S1 includes a plurality of carbon fibers arranged in parallel.
  • the direction in which each of the carbon fibers extends is inclined with respect to the axial direction.
  • the direction in which each carbon fiber extends forms an angle of not less than 30° and not greater than 60° with the axial direction. In the present embodiment, the angle is 45°.
  • the first sheet S1 is 100 mm wide and 340 mm long.
  • the second sheet S2 extends over the entirety of the shaft 4.
  • the second sheet S2 is generally rectangular.
  • the second sheet S2 includes a plurality of carbon fibers arranged in parallel.
  • the direction in which each of the carbon fibers extends is inclined with respect to the axial direction.
  • the direction in which each carbon fiber extends forms an angle of not less than -60° and not greater than -30° with the axial direction. In the present embodiment, the angle is -45°.
  • the second sheet S2 is 100 mm wide and 340 mm long.
  • the direction of the inclination of the carbon fibers in the second sheet S2 is opposite to the direction of the inclination of the carbon fibers in the first sheet S1.
  • the direction of the inclination of the carbon fibers in the second fiber-reinforced layer is opposite to the direction of the inclination of the carbon fibers in the first fiber-reinforced layer.
  • a bias structure is achieved by the first and second fiber-reinforced layers.
  • the first and second fiber-reinforced layers contribute to the flexural rigidity and torsional rigidity of the shaft 4.
  • the first and second fiber-reinforced layers particularly contribute to the torsional rigidity of the shaft 4.
  • the third sheet S3 is localized towards the tip end 20 of the shaft 4.
  • the third sheet S3 is generally trapezoidal.
  • the third sheet S3 includes a plurality of carbon fibers arranged in parallel.
  • the direction in which each of the carbon fibers extends is inclined with respect to the axial direction.
  • the direction in which each carbon fiber extends forms an angle of not less than 30° and not greater than 60° with the axial direction. In the present embodiment, the angle is 45°.
  • the third sheet S3 is 40 mm wide, 185 mm long on the upper base, and 195 mm long on the lower base.
  • the fourth sheet S4 is localized towards the tip end 20 of the shaft 4. In the axial direction, the location of the fourth sheet S4 is the same as the location of the third sheet S3.
  • the fourth sheet S4 is generally trapezoidal.
  • the fourth sheet S4 includes a plurality of carbon fibers arranged in parallel. The direction in which each of the carbon fibers extends is inclined with respect to the axial direction. The direction in which each carbon fiber extends forms an angle of not less than -60° and not greater than -30° with the axial direction. In the present embodiment, the angle is -45°.
  • the fourth sheet S4 is 40 mm wide, 185 mm long on the upper base, and 195 mm long on the lower base.
  • the direction of the inclination of the carbon fibers in the fourth sheet S4 is opposite to the direction of the inclination of the carbon fibers in the third sheet S3.
  • the direction of the inclination of the carbon fibers in the fourth fiber-reinforced layer is opposite to the direction of the inclination of the carbon fibers in the third fiber-reinforced layer.
  • a bias structure is achieved by the third and fourth fiber-reinforced layers.
  • the third and fourth fiber-reinforced layers contribute to the flexural rigidity and torsional rigidity of the middle portion 14 and tip portion 16.
  • the third and fourth fiber-reinforced layers particularly contribute to the torsional rigidity of the middle portion 14 and tip portion 16.
  • the fifth sheet S5 is localized towards the butt end 18 of the shaft 4.
  • the fifth sheet S5 is generally trapezoidal.
  • the fifth sheet S5 includes a plurality of carbon fibers arranged in parallel.
  • the direction in which each of the carbon fibers extends is the same as the axial direction. In other words, the direction in which each carbon fiber extends forms an angle of substantially 0° with the axial direction.
  • the fifth sheet S5 is 80 mm wide, 145 mm long on the upper base, and 155 mm long on the lower base.
  • the carbon fibers contained in the fifth sheet S5 are oriented substantially in the axial direction.
  • the carbon fibers are oriented substantially in the axial direction also in the fifth fiber-reinforced layer.
  • the structure in which the carbon fibers are oriented substantially in the axial direction is herein referred to as a "straight structure".
  • the fifth fiber-reinforced layer has a straight structure.
  • the fifth sheet S5 is located in a zone including the first measurement point P1 and not including the second and third measurement points P2 and P3 in the axial direction.
  • the fifth fiber-reinforced layer is also located in the zone including the first measurement point P1 and not including the second and third measurement points P2 and P3 in the axial direction.
  • the fifth fiber-reinforced layer particularly contributes to the flexural rigidity of the butt portion 12.
  • the sixth sheet S6 is localized towards the tip end 20 of the shaft 4.
  • the sixth sheet S6 is generally trapezoidal.
  • the sixth sheet S6 includes a plurality of carbon fibers arranged in parallel.
  • the direction in which each of the carbon fibers extends is inclined with respect to the axial direction.
  • the direction in which each carbon fiber extends forms an angle of not less than 30° and not greater than 60° with the axial direction. In the present embodiment, the angle is 45°.
  • the sixth sheet S6 is 20 mm wide, 95 mm long on the upper base, and 105 mm long on the lower base.
  • the seventh sheet S7 is localized towards the tip end 20 of the shaft 4. In the axial direction, the location of the seventh sheet S7 is the same as the location of the sixth sheet S6.
  • the seventh sheet S7 is generally trapezoidal.
  • the seventh sheet S7 includes a plurality of carbon fibers arranged in parallel. The direction in which each of the carbon fibers extends is inclined with respect to the axial direction. The direction in which each carbon fiber extends forms an angle of not less than -60° and not greater than -30° with the axial direction. In the present embodiment, the angle is -45°.
  • the seventh sheet S7 is 20 mm wide, 95 mm long on the upper base, and 105 mm long on the lower base.
  • the direction of the inclination of the carbon fibers in the seventh sheet S7 is opposite to the direction of the inclination of the carbon fibers in the sixth sheet S6.
  • the direction of the inclination of the carbon fibers in the seventh fiber-reinforced layer is opposite to the direction of the inclination of the carbon fibers in the sixth fiber-reinforced layer.
  • a bias structure is achieved by the sixth and seventh fiber-reinforced layers.
  • the sixth and seventh fiber-reinforced layers contribute to the flexural rigidity and torsional rigidity of the tip portion 12.
  • the sixth and seventh fiber-reinforced layers particularly contribute to the torsional rigidity of the tip portion 12.
  • the eighth sheet S8 is localized towards the butt end 18 of the shaft 4.
  • the eighth sheet S8 is generally trapezoidal.
  • the eighth sheet S8 includes a plurality of carbon fibers arranged in parallel.
  • the direction in which each of the carbon fibers extends is the same as the axial direction. In other words, the direction in which each carbon fiber extends forms an angle of substantially 0° with the axial direction.
  • the eighth sheet S8 is 40 mm wide, 235 mm long on the upper base, and 245 mm long on the lower base.
  • the carbon fibers contained in the eighth sheet S8 are oriented substantially in the axial direction.
  • the carbon fibers are oriented substantially in the axial direction also in the eighth fiber-reinforced layer.
  • the eighth fiber-reinforced layer has a straight structure.
  • the carbon fibers are subjected to a strong tension. The tension acts to prevent further deflection of the shaft 4.
  • the carbon fibers contribute to the flexural rigidity of the shaft 4.
  • the eighth sheet S8 is located in a zone including the first and second measurement points P1 and P2 and not including the third measurement point P3 in the axial direction.
  • the eighth fiber-reinforced layer is also located in the zone including the first and second measurement points P1 and P2 and not including the third measurement point P3 in the axial direction.
  • the eighth fiber-reinforced layer particularly contributes to the flexural rigidity of the butt portion 12 and middle portion 14.
  • the first and second fiber-reinforced layers extend from the butt end 18 to the tip end 20. These fiber-reinforced layers can contribute to the durability of the shaft 4.
  • the sheets shown in FIG. 5 are sequentially wound on a mandrel.
  • a stack of the first and second sheets S1 and S2 may be wound on the mandrel.
  • a stack of the third and fourth sheets S3 and S4 may be wound on the mandrel.
  • a stack of the sixth and seventh sheets S6 and S7 may be wound on the mandrel.
  • another sheet may be wound on the mandrel.
  • An example of the other sheet is a sheet containing glass fibers.
  • a wrapping tape is further wound on the above sheets.
  • the mandrel, prepregs (sheets S1 to S8), and wrapping tape are heated by means such as an oven.
  • the heating fluidizes the matrix resin. Further heating induces a curing reaction of the resin, as a result of which a shaped product is obtained.
  • the shaped product is subjected to various processes such as end face machining, polishing, and painting, and thus the shaft 4 is completed.
  • FIG. 6 is a schematic diagram showing a method of measuring a flexural rigidity value EI of the shaft 4 of the racket 2 of FIG. 1 .
  • FIG. 6 shows the measurement at a measurement point P located at a distance L1 from the grip 8.
  • the shaft 4 is supported from below at first and second support points 28 and 30.
  • the distance from the measurement point P to the first support point 28 is 30 mm.
  • the distance from the measurement point P to the second support point 30 is 30 mm.
  • the measurement is performed using a universal testing machine (manufactured by INTESCO Co., Ltd. under the product name "2020").
  • the testing machine includes an indenter 32.
  • the indenter 32 is in the shape of a hemisphere.
  • the radius of curvature of the hemisphere is 20 mm.
  • the indenter 32 gradually descends at a speed of 2 mm/min.
  • the indenter 32 comes into contact with the measurement point P and presses the shaft 4.
  • the pressing causes gradual deflection of the shaft 4.
  • the amount of deflection B (m) of the shaft 4 is measured at the moment when the load applied to the shaft 4 by the indenter 32 reaches 100 N.
  • the amount of deflection B is substituted into the following equation to calculate the flexural rigidity value EI (Nm 2 ).
  • EI F ⁇ L 2 3 / 48 ⁇ B
  • F is the load (N)
  • L2 is the distance (m) between the two support points
  • B is the amount of deflection (m).
  • the load F is 100 N
  • the distance L2 is 0.06 m.
  • the flexural rigidity value EI of the shaft 4 may be measured in the absence of the grip 8 and frame 6.
  • the flexural rigidity values EI are measured at the first, second, and third measurement points P1, P2, and P3.
  • the distance L1 from the grip 8 to each measurement point is as follows.
  • the flexural rigidity value EI(1) at the first measurement point P1 is 4.97 Nm 2
  • the flexural rigidity value EI(2) at the second measurement point P2 is 3.56 Nm 2
  • the flexural rigidity value EI(3) at the third measurement point P3 is 2.06 Nm 2 .
  • the flexural rigidity distribution of the shaft 4 is shown in the graph of FIG. 7 .
  • the flexural rigidity value EI(2) at the second measurement point P2 is smaller than the flexural rigidity value EI(1) at the first measurement point P1. Furthermore, in the shaft 4, the flexural rigidity value EI(3) at the third measurement point P3 is smaller than the flexural rigidity value EI(2) at the second measurement point P2. As shown in FIG. 7 , the shaft 4 has a flexural rigidity distribution with a downward-sloping profile.
  • the fifth fiber-reinforced layer is located in a zone including the first measurement point P1 and not including the second and third measurement points P2 and P3 in the axial direction.
  • the eighth fiber-reinforced layer is located in a zone including the first and second measurement points P1 and P2 and not including the third measurement point P3 in the axial direction.
  • This layer structure can attain a flexural rigidity distribution with a downward-sloping profile.
  • Another layer structure can also attain a flexural rigidity distribution with a downward-sloping profile.
  • Local presence of a fiber-reinforced layer having a straight structure in the butt portion 12 can result in a flexural rigidity distribution with a downward-sloping profile.
  • the shaft 4 having a flexural rigidity distribution with a downward-sloping profile is suitable for the lob.
  • the player who performs the lob using the racket 2 can easily achieve an intended trajectory of the shuttlecock. With the use of the racket 2, the variation in the height of the trajectory of the shuttlecock in the lob is small.
  • the reason why the racket 2 according to the present invention is suitable for the lob is that the flexural rigidity distribution shown in FIG. 7 matches the deformation behavior of the shaft 4 in the lob. In the lob, the shaft 4 is deflected mainly in the out-of-plane direction (Z direction).
  • the racket 2 according to the present invention is suitable also for shots which are other than the lob and in which the shaft 4 is deflected mainly in the out-of-plane direction.
  • the flexural rigidity distribution can be adjusted by changing the location of the prepregs, the number of the prepregs, the width of the prepregs, the length of the prepregs, the angle of the fibers, the weight per unit area of the fibers, and the elastic modulus of the fibers.
  • the ratio (EI(2)/EI(1)) of the flexural rigidity value EI(2) to the flexural rigidity value EI(1) is preferably not greater than 0.95, more preferably not greater than 0.87, and particularly preferably not greater than 0.82. From the viewpoint of ease of production of the shaft 4, the ratio is preferably not less than 0.30.
  • the ratio (EI(3)/EI(2)) of the flexural rigidity value EI(3) to the flexural rigidity value EI(2) is preferably not greater than 0.90, more preferably not greater than 0.77, and particularly preferably not greater than 0.70. From the viewpoint of ease of production of the shaft 4, the ratio is preferably not less than 0.25.
  • the ratio (EI(3)/EI(1)) of the flexural rigidity value EI(3) to the flexural rigidity value EI(1) is preferably not greater than 0.80, more preferably not greater than 0.60, and particularly preferably not greater than 0.50. From the viewpoint of ease of production of the shaft 4, the ratio is preferably not less than 0.20.
  • the difference (EI(2) - EI(1)) between the flexural rigidity value EI(2) and the flexural rigidity value EI(1) is preferably not greater than -0.30 Nm 2 , more preferably not greater than -0.62 Nm 2 , and particularly preferably not greater than -0.80 Nm 2 . From the viewpoint of ease of production of the shaft 4, the difference is preferably not less than -3.00 Nm 2 .
  • the difference (EI(3) - EI(2)) between the flexural rigidity value EI(3) and the flexural rigidity value EI(2) is preferably not greater than -0.50 Nm 2 , more preferably not greater than -0.93 Nm 2 , and particularly preferably not greater than -1.10 Nm 2 . From the viewpoint of ease of production of the shaft 4, the difference is preferably not less than -3.00 Nm 2 .
  • the difference (EI(3) - EI(1)) between the flexural rigidity value EI(3) and the flexural rigidity value EI(1) is preferably not greater than -0.80 Nm 2 , more preferably not greater than -1.50 Nm 2 , and particularly preferably not greater than -1.80 Nm 2 . From the viewpoint of ease of production of the shaft 4, the difference is preferably not less than -6.00 Nm 2 .
  • FIG. 3 shows the first, second, and third measurement points P1, P2, and P3.
  • the inner diameter Di of the shaft 4 is substantially constant from the first measurement point P1 to the third measurement point P3.
  • the shaft 4 can be produced using a mandrel having a simple shape. In the production of the shaft 4, the winding of the prepregs is easy.
  • the shaft 4 may have a slight variation in the inner diameter Di due to, for example, production error.
  • the ratio (Di1/Di2) of the maximum inner diameter Di1 to the minimum inner diameter Di2 in the zone from the first measurement point P1 to the third measurement point P3 is preferably not greater than 1.10, more preferably not greater than 1.05, and particularly preferably not greater than 1.03.
  • the ratio (Di1/Di2) is ideally 1.00.
  • the outer diameter Do of the shaft 4 is substantially constant from the first measurement point P1 to the third measurement point P3.
  • the shaft 4 can be produced using a mandrel having a simple shape. In the production of the shaft 4, the winding of the prepregs is easy.
  • the shaft 4 may have a slight variation in the outer diameter Do due to, for example, production error.
  • the ratio (Do1/Do2) of the maximum outer diameter Do1 to the minimum outer diameter Do2 in the zone from the first measurement point P1 to the third measurement point P3 is preferably not greater than 1.10, more preferably not greater than 1.05, and particularly preferably not greater than 1.03.
  • the ratio (Do1/Di2) is ideally 1.00.
  • the ratio (W1/W2) of the weight W1 of the shaft 4 in the zone from the first measurement point P1 to the second measurement point P2 to the weight W2 of the shaft 4 in the zone from the second measurement point P2 to the third measurement point P3 is preferably not less than 0.95 and not greater than 1.05.
  • the shaft 4 in which the ratio is not less than 0.95 and not greater than 1.05 is free from a significant local increase in weight.
  • the player can swing the racket 2 including the shaft 4 without feeling discomfort.
  • the ratio (W1/W2) is more preferably not less than 0.97 and not greater than 1.03 and particularly preferably not less than 0.98 and not greater than 1.02.
  • FIGS. 1 to 6 A badminton racket as shown in FIGS. 1 to 6 was produced.
  • the flexural rigidity values EI of the racket are shown in Table 1 below and in FIG. 7 .
  • Badminton rackets of Examples 2 and 3 and Comparative Example were obtained in the same manner as the badminton racket of Example 1, except for changing the prepreg arrangement.
  • the flexural rigidity values EI of the rackets are shown in Table 1 below and in FIGS. 8 to 10 .
  • a shuttlecock was launched by a launching machine. A player was caused to perform lob on the shuttlecock, and a video image of the trajectory of the shuttlecock was captured. The image was analyzed to measure the height at which the shuttlecock passed above the net. The measurement was conducted six times, and an average height Hav, a maximum height Hmax, and a minimum height Hmin were determined. The results are shown in Table 1 below.
  • the badminton racket according to the present invention is suitable for players who play in a style involving frequent use of lob.
  • the racket is suitable also for players who play in other styles.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Physical Education & Sports Medicine (AREA)
  • Golf Clubs (AREA)
EP21757626.3A 2020-02-18 2021-01-19 Federballschläger Pending EP4098334A4 (de)

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JP2020025154A JP7404920B2 (ja) 2020-02-18 2020-02-18 バドミントンラケット
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JP3024578B2 (ja) * 1996-12-24 2000-03-21 ブリヂストンスポーツ株式会社 バトミントンラケット
CN1099302C (zh) * 1997-09-26 2003-01-22 株式会社高纤 羽毛球拍
JPH11262545A (ja) * 1998-03-17 1999-09-28 Mizuno Corp バドミントンシャフト
JP3582778B2 (ja) 1998-07-24 2004-10-27 ダイワ精工株式会社 中実杆を使用した竿杆
JP4328380B1 (ja) * 2008-10-09 2009-09-09 株式会社薫風 バドミントンラケット
JP5230835B1 (ja) 2012-08-31 2013-07-10 グローブライド株式会社 バドミントンラケットに用いられるシャフトを製造する方法
CN108310736A (zh) 2018-04-28 2018-07-24 邬惠林 基于黄金比例的羽毛球拍
CN208465113U (zh) 2018-07-06 2019-02-05 南京胜利体育用品实业有限公司 一种羽毛球拍
CN108853971B (zh) 2018-07-06 2024-05-14 南京胜利体育用品实业有限公司 一种羽毛球拍及其制造方法
JP7326978B2 (ja) * 2019-08-08 2023-08-16 住友ゴム工業株式会社 バドミントンラケットの仕様決定方法及びシャフト挙動の解析方法

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WO2021166517A1 (ja) 2021-08-26
JP2021129632A (ja) 2021-09-09

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