JP2011024617A - Racket frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a racket frame providing a high hitting angle and high initial velocity when a ball is hit. <P>SOLUTION: The tennis racket frame 1 is made of fiber-reinforced synthetic resin, and includes a face portion 2, a shaft portion 3 and a grip portion 4. When the deflection amount of the racket frame measured by fixing the proximal end of the grip portion and applying the load of 6 kg in the direction perpendicular to the face surface to the front end of the racket frame is X (mm) and the warping amount measured by applying the load of 100 kg in the direction perpendicular to the axis of the racket frame to the face portion is Y (mm), (X, Y) are present within a triangular region formed by connecting points A (8, 21.5), B (8, 13), and C (13, 21.5) on the X-Y coordinate surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tennis racket frame, and more particularly to a racket frame made of fiber-reinforced synthetic resin.

  As shown in FIG. 5, the tennis racket frame 1 includes a face part 2 on which a gut is stretched, a grip part 4 gripped by a player, and a shaft part 3 connecting the face part 2 and the grip part 4. Have. A tennis racket is formed by stretching a gut on the face portion 2.

  As a racket frame for tennis, those made of fiber reinforced synthetic resin are widely used. Such a fiber-reinforced synthetic resin racket frame is formed by laminating a prepreg sheet around a core material, placing it in a frame-shaped cavity of a mold, and heating it (for example, Japanese Patent Laid-Open No. 8-215348). Issue gazette).

  By the way, conventionally, there is a racket frame that uses the bending of the entire racket frame at the time of swing and ball hit to bring out high resilience performance.

  As described in JP-A-8-215347 and JP-A-8-215348, this bending is affected by the bending deflection amount and the hoop deflection amount of the racket frame. In the publication, the measurement method of these characteristics and the preferred range are described as follows.

I Bending deflection
The bending amount of the racket frame 1 is as follows when the base end of the racket frame 1 is fixed over a range of 150 mm as shown in FIG. 4 and a load P of 6 kg is applied to the tip of the racket frame 1 in the direction perpendicular to the gut surface. The bending displacement W (mm) at the tip is measured.

II Hoop deflection
As shown in FIG. 5, the racket frame 1 has an axial direction parallel to the surface plate 7, and a load of 100 kg in a direction perpendicular to the axial direction is applied to the maximum width portion of the head portion (face portion). The displacement (mm) is measured.

  When the hoop deflection amount is less than 12 mm, the hoop deflection deformation at the time of ball hit becomes excessively small, and the resilience and spin imparting properties become excessively low.

  Japanese Patent Application Laid-Open No. 2002-35169 describes a racket frame having a bending deflection amount of 10 to 30 mm and a hoop deflection amount of 10 to 25 mm.

  Japanese Patent Laid-Open No. 9-299516 discloses a fiber reinforced synthetic resin racquet frame in which the back width T (thickness in the direction perpendicular to the face surface) of the face portion is 22 mm or less and the bending deflection is 14 to 22 mm. Are listed. The racket frame of the same issue is for advanced users who are easy to spin and have good controllability.

JP-A-8-215347 JP-A-8-215348 JP 2002-35169 A Japanese Patent Laid-Open No. 9-299516

  In the above prior art, the launch angle when a ball is hit with a tennis racket is not considered.

  It is an object of the present invention to provide a racket frame that increases the launch angle when a ball is hit.

  The racket frame of claim 1 is a fiber reinforced synthetic resin tennis racket frame having a face portion, a shaft portion, and a grip portion. The base end of the grip portion is fixed, and the front end of the racket frame is perpendicular to the face surface. The amount of deflection of the racket frame when measured with a load of 6 kg on X is X (mm), and the amount of hoop deflection when measured with a load of 100 kg perpendicular to the axis of the racket frame on the face portion. Is Y (mm), within a triangular region connecting points A (8, 21.5), B (8, 13) and C (13, 21.5) on the XY coordinate plane ( X, Y) exists.

  The racket frame of claim 2 connects points A (8, 21.5), D (8, 16) and E (11.2, 21.5) on the XY coordinate plane in claim 1. The feature is that (X, Y) exists in a triangular region.

  When the present inventor conducted various studies, the bending deflection amount X (mm) and the hoop deflection amount Y (mm) are points A (8, 21.5) and B (8, 13) on the XY coordinate plane. ) And C (13, 21.5), it was recognized that the ball launch angle was increased when (X, Y) was present in the triangular region.

  The present invention is based on such knowledge.

(A) The figure is a front view of the racket frame which concerns on embodiment, (b) The figure is a side view. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is explanatory drawing of the measuring method of bending deflection amount. It is explanatory drawing of the measuring method of a hoop deflection amount. It is explanatory drawing of the measuring method of a twist angle. It is a bending deflection amount (X) -hoop deflection amount (Y) coordinate diagram.

  Hereinafter, embodiments will be described with reference to FIGS. 1 to 3.

  FIG. 1 (a) is a front view of the racket frame 1 according to the embodiment, and FIG. 1 (b) is a right side view thereof. The racket frame 1 includes a face portion 2, a shaft portion 3, and a grip portion 4. The face part 2, the shaft part 3, and the grip part 4 are all made of fiber reinforced synthetic resin. The face portion 2 is provided with a gut insertion hole, and the gut is stretched through a grommet (not shown).

  The base end of the grip portion is fixed, and the bending amount of the racket frame when measured by applying a load of 6 kg to the front end of the racket frame in the direction perpendicular to the face surface is defined as X (mm). When the hoop deflection when measured with a load of 100 kg perpendicular to the racket frame axis is Y (mm), points A (8, 21.5), B (8, 13) and (X, Y) exist in a triangular region connecting C (13, 21.5).

  In this embodiment, the face part 2 is substantially elliptical. The face portion 2 includes a large back width portion 5 constituting the grip portion 4 side and a small back width portion 6 constituting the top portion side. The large back width portion 5 extends including the end portion of the face portion 2 on the grip portion 4 side.

The “large back width portion” means that when the back width of the face portion where the back width (thickness in the direction perpendicular to the face surface) is the maximum is the maximum back width value _Tmax , It means a portion where the back width including the largest portion is a maximum back width value T _max −0.2 mm or more and a maximum back width value T _max or less. In addition, the “small width portion” means a portion of the face portion whose back width is less than the maximum back width value T _max −0.2 mm.

Racket long axial length _{L 1} of the Daicel width portion 5 is 25 to 60% of the length _{L 0} of the racquet longitudinal direction of the face portion 2, and more preferably 30-50%. Increasing the L _1, the amount of bending deflection is reduced.

The length of the racquet longitudinal direction of the face portion 2 _{L 0} is 300~380mm especially about 330~350mm are preferred. In this case, Daicel the length _{L 1} of the wide portion 5 is a 70~170mm particularly 100~140mm about. The length L ₀ of the face portion 2 in the racket major axis direction is a distance from the outer peripheral surface on the top side of the face portion 2 to the outer peripheral surface on the shaft portion 3 side.

The maximum back width value T _max is preferably about 22 to 30 mm, particularly about 24 to 28 mm.

In the present embodiment, the back width of the small back width portion 6 gradually decreases from the end portion on the large back width portion 5 side toward the top side, and the end portion on the top portion side of the face portion 2 is the smallest. It is the back width (minimum back width value T _min ). However, the shape of the small back width portion 6 is not limited to this as long as the back width is less than T _max −0.2 mm. For example, the back width partially extends from the grip portion 4 side to the top side. The back width may be partially the same from the grip portion 4 side to the top side. In the present embodiment, the back width of the shaft portion 3 gradually decreases from the face portion 2 side toward the grip portion 4 side, and the shaft portion 3 has the largest back width at the end on the grip portion 4 side. and it has a small back width value T _S. In this embodiment, the minimum back span value T _S of the shaft portion 3 is smaller than the minimum spine width value T _min of the face portion 2 may be identical to the minimum spine width value T _min It may be larger than the minimum back width value _Tmin .

The difference T _max −T _min between the maximum back width value T _max and the minimum back width value T _min is preferably about 2 to 8 mm, particularly about 4 to 6 mm. Minimum back span value _{T min} is preferably 80 to 90% of the maximum back span value _{T max.}

Racket long axial length _{L 2} of small spine width portion 6 180~260mm especially about 200~250mm are preferred. Note that L ₁ + L ₂ = L ₀ .

  In the present embodiment, the thickness S in the face surface direction of the face portion 2 decreases from the grip portion 4 side toward the top side.

The thickness S of the face portion 2 in the face surface direction is preferably 9.5 to 10.8 mm, particularly about 10 mm. The minimum value _{S min} of the thickness S is in particular about 95% about 90% to 100% of the maximum value _{S max} is preferred.

Reducing the thickness S ₁ of the face direction of the Daicel width portion 5, hoop deflection of the face part 2 (described later) is increased. Thus, when the amount of deflection of the hoop was large, a tendency for the initial speed to increase was recognized. The reason is considered to be that the amount of deformation of the ball at the time of hitting the tennis ball becomes small, and therefore energy loss accompanying the deformation of the ball is reduced. The _{S 1} is, 10～11Mm especially about 10.2~10.8mm are preferred.

The ratio T _max / S ₁ × 100% of the thickness S ₁ (FIG. 2) of the face portion 2 in the large back width portion 5 in the face surface direction and the maximum back width value T _mzx is 230 to 290%, particularly 245 to 270. % Is preferred. This is for suppressing or eliminating an increase in weight of the racket frame even if the back width of the large back width portion 5 is increased.

  As described above, the bending deflection amount X and the hoop deflection amount Y (mm) are points A (8, 21.5), B (8, 13) and C (13, 21.5) on the XY coordinate plane. The tennis racket using the racket frame existing in the triangular area connecting the) has a large launch angle. In addition, a tendency for the spin rate to increase and a tendency for the initial speed to increase are also observed. The reason why the launch angle of the racket frame 1 increases when (X, Y) exists in the region surrounded by the points A, B, and C is presumed as follows.

  That is, in general, a tennis racket is often swung by an upper swing so as to rub the ball diagonally upward from below so as to apply a top spin to the hit ball. In this case, the face surface hits the ball slightly downward from the vertical surface. Therefore, a force is applied from the ball to the face surface so as to push it back toward the rear side and slightly in the lower half side (ground side). When the amount of bending deflection is large, the top side of the face portion 2 is slightly delayed behind the face center, so that the downward degree of the face surface becomes stronger and the launch angle is lowered by this delay. Further, the amount of the top side pushed back by the reaction force received from the ball increases, and this also reduces the launch angle. When the amount of bending deflection is small, the delay on the top side at the time of swing is reduced, and the amount by which the top side is pushed back from the ball is also reduced, thereby increasing the launch angle.

  Further, when the ball hits the ball, while the ball is in contact with the gut surface, both side portions of the face portion 2 (the left side portion and the right side portion in FIG. 1A) are subjected to gut tension. The face portion 2 is deformed so as to approach. If the hoop deflection is large, the ball will dig deeply into the gut, and while it is digging, the ball will shift slightly to the lower side (ground side) than the center while the lower half side (ground side) of the face surface is the upper half. Is pressed stronger than the side (sky side), and the downward degree of the face surface is increased by that amount, and the launch angle is lowered.

  Thus, the launch angle tends to increase as the bending deflection and the hoop deflection both decrease. This tendency is also affected by the head speed. In other words, the higher the head speed, in other words, the harder the hitter, the greater the bending and hoop deflection of the racket frame at the time of the ball hit. Therefore, in the present invention, the bending deflection amount and the hoop deflection amount are both set lower than a predetermined value, and when the bending deflection amount is reduced assuming a hard hitter, an allowable range of the hoop deflection amount is set accordingly. Set smaller. However, the player may prefer a larger amount of hoop deflection. This is because it is easy to apply a spin by securing the contact time between the ball and the gut surface when the ball hits, and because the impact when the ball is detached from the core of the face surface is easily absorbed. .

  Therefore, in the present invention, even when the bending deflection amount is set small, the upper limit value of the allowable range of the hoop deflection amount is the same as that when the bending deflection amount is set to be large.

  In the XY coordinate system of FIG. 7, when the bending deflection amount X and the hoop deflection amount Y are in a triangular region surrounded by points A, B, and C, the launch angle is large. Also, the spin rate and initial speed increase. Further, when the amount of bending deflection is set to 13 mm or less, the feeling of swinging is improved, and when it is set to 8 mm or more, it is possible to release a shot with a bend. Further, when the hoop deflection amount is 21.5 mm or less, the spin amount is prevented from being excessive, and when it is 13 mm or more, the resilience is improved. When the bending deflection amount X and the hoop deflection amount Y are in the range surrounded by the points D, E, and F, the above swing feeling, bending, spin amount, and resilience are more preferable while ensuring the launch angle. Become.

In this embodiment, L ₀ , L ₁ , L ₂ , T _max , and T _min are set so that the bending deflection amount X and the hoop deflection amount Y enter the region surrounded by the points A, B, and C. .

  In this embodiment, as shown in FIG. 3, a reinforcing partition wall portion 3 a is provided on the shaft portion 3. The reinforcing partition wall 3a is located on the extended surface of the face surface. The reinforcing partition wall portion 3a may be provided on the entire shaft portion 3, may be provided only on a part thereof, or may be omitted. By providing the reinforcing partition wall portion 3a, the bending amount of the racket frame 1 is reduced. The reinforcing partition wall 3a may be provided in a direction perpendicular to the face surface or in an oblique direction. Further, both the reinforcing partition wall portion 3a in the face surface direction and the reinforcing partition wall portion in the direction perpendicular to the face surface may be provided.

The racket frame of the present invention is made of fiber reinforced synthetic resin. As this reinforcing fiber, those having a tensile modulus of 10 to 40 ton / mm ^2, particularly 16 to 30 ton / mm ² are suitable, and carbon fiber, boron fiber, alumina fiber, ultrafine iron wire, Ti—Si—C—O. System fiber (trade name Tyranno fiber), aromatic polyamide fiber, aromatic polyester fiber, ultra-high molecular weight polyethylene fiber, etc. can be used, but carbon fiber is also preferred from the viewpoint of cost.

  As the synthetic resin, epoxy resin, nylon and the like are preferable, but epoxy resin is preferable in terms of strength, durability and price.

  In order to manufacture the racket frame of the present invention, a fiber-reinforced synthetic resin racket frame in which a plurality of prepreg sheets are laminated around a core material and placed in a cavity having a frame shape of a mold and heated. According to this manufacturing method. In addition, the elasticity modulus of a fiber reinforced synthetic resin can be changed by changing the quantity and orientation direction of the fiber in a prepreg sheet. Moreover, the density of a fiber reinforced synthetic resin can be changed by changing the quantity of the fiber in a prepreg sheet.

  The racket frame of the present invention is made of fiber-reinforced synthetic resin, but a metal such as titanium or a different material such as rubber may be partially used.

The above embodiment is an example of the present invention, and the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the thickness S in the face surface direction of the face portion 2 is reduced from the grip portion 4 side toward the top side. However, the present invention is not limited to this, and the grip portion is partially limited. The thickness S may be the same from the 4 side toward the top side. For example, the thickness S ₁ of the face direction of Daicel width portion 5 may be the same toward the top side from the grip portion side.

Examples 1-8, Comparative Examples 1-4
A racket frame having the shape shown in FIG. 1 and specifications as shown in Table 1 was manufactured using a carbon fiber reinforced epoxy resin. The overall length of this racket frame is 685 mm, and the area of the gut surface is 100 cm ² .

A nylon gut having a cross-sectional area of 1.77 mm ² was stretched on this racket frame with a tension of 54 pounds (24.5 kg) to obtain a tennis racket.

  The tennis racket was mounted on a trial robot machine, the tennis ball flying horizontally at a speed of 45 km / h was hit back, photographed with a high-speed camera, and the launch angle and initial speed were measured. The face surface was slightly downward (by 15 °) from the vertical surface. The swing trajectory of the face part was upward by 30 ° with respect to the horizontal, and a top spin was applied. The results are shown in Table 1.

  From Table 1, it is recognized that the tennis rackets of Examples 1 to 8 have a high launch angle and a large initial speed.

1 Racket frame 2 Face part 3 Shaft part 4 Grip part 5 Maximum back width part

Claims (2)

In a tennis racket frame made of fiber reinforced synthetic resin having a face part, a shaft part and a grip part,
The base end of the grip portion is fixed, and the bending amount of the racket frame when measured by applying a load of 6 kg to the front end of the racket frame in the direction perpendicular to the face surface is X (mm).
When the hoop deflection amount when measured by applying a load of 100 kg in a direction perpendicular to the racket frame axis to the face portion is Y (mm), the point A (8, 21.5) on the XY coordinate plane ), B (8, 13) and C (13, 21.5), a racket frame characterized in that (X, Y) exists in a triangular area.   In claim 1, within a triangular region connecting points A (8, 21.5), D (8, 16) and E (11.2, 21.5) on the XY coordinate plane (X, A racket frame characterized by the presence of Y).

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