JPH07178204A - Racket - Google Patents

Abstract

PURPOSE:To make it possible to obtain sufficient repulsive performance, etc., even if a player having a tendency to hit a ball with the left side or right side of a gut surface. CONSTITUTION:First and second boundary lines P1, P2 which pass the ends 14a, 14b in the minor axis X direction of the gut surface and are parallel with the major axis Y are set. The region held by the major axis Y and the first boundary line P1 is defined as the first region A1 and the region held by the major axis Y and the second boundary line P2 as the second region A2. The ratio m1/m2 between the mean value m1 of the length in the minor axis X direction of the mesh M formed by the intersected point of the gut K in the major axis Y direction the first region A1, and the jut J in the minor axis X direction and the mean value m2 of the length in the minor axis X direction of the mesh M in the second region A2 is set at >=0.2 to <=0.9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a racket such as a tennis racket, a badminton racket, a squash racket which is stretched and used, and more particularly to a racket in which the surface pressure distribution on the gut surface of the racket is asymmetric.

[0002]

2. Description of the Related Art As shown in FIG. 11, in a racket 1 such as a tennis racket, generally, a method of tensioning a gut J (gut pattern) is a surface on which a gut that is in agreement with a central axis C of the racket 1 is stretched (gut surface). 2) is symmetrical with respect to the major axis Y, and the force (contact pressure) required to give a constant displacement in the direction (out-of-plane direction) perpendicular to the gut surface 2 is symmetrical with respect to the major axis Y. It is distributed. Further, when the surface pressure is distributed symmetrically in this way, it is set so that when hitting at the central portion 2a of the gut surface 2, suitable rebound performance, spin performance, feel at impact, controllability, etc. are obtained. .

[0003]

However, some players using a racket have a left side 2 of the gut surface 2.
There is a player who tends to hit with b and a player who tends to hit with the right side 2c of the gut surface 2. Such a player has the above-mentioned symmetrical surface pressure distribution, and the resilience performance in the central portion 2a. If the racket 1 set such that the above is suitable is used, sufficient resilience performance and the like cannot be obtained.

The present invention has been made in order to solve the above problems in the conventional racket, and has sufficient resilience performance even when a player who tends to hit on the left side or the right side of the gut surface hits. It was made for the purpose of being able to obtain.

[0005]

SUMMARY OF THE INVENTION Therefore, according to the present invention, a first boundary line and a second boundary line, which pass through the ends of the gut surface in the minor axis direction and are parallel to the major axis, are set. The region sandwiched between the long axis and the first boundary line is defined as the first region, and the region sandwiched between the long axis and the second boundary line is defined as the second region, and the gut in the long axis direction and the short axis direction in the first region are defined. And the average value of the lengths of the meshes formed by the intersections of the guts in the short axis direction,
The average value of the length in the short axis direction of the mesh in the region is different, and, of the average values of the length in the short axis direction of the mesh, the average of the larger average value of the smaller values The racket is characterized in that the ratio to the value is set to 0.2 or more and 0.9 or less.

[0006]

In the racket of the present invention having the above structure, the gut pattern is asymmetrical with respect to the major axis, and the first pattern
Also, in the region where the gap between the guts in the major axis direction is set tightly in the second region, the surface pressure is high and the controllability is good.
On the other hand, in the region where the gap between the guts in the major axis direction is set to be sparse, the surface pressure is low, and the resilience performance and spin performance are good.

[0007]

1 and 2 show a racket according to the present invention. 1 and 2B show the racket 11 shown in FIG.
It is a drawing seen from the arrow A direction in (A), and in the following description, unless otherwise specified, "right side" or "left side" refers to the direction seen from the arrow A direction (one side of the racket 11). (When viewed from the surface 11a).

In the racket 11, a gut J in the minor axis X direction and a gut K in the major axis Y direction are stretched in a plurality of gut holes formed in the gut tensioned portion 12a of the frame 12 and the gut surface 14 is formed.
Is formed.

Here, the minor axis X is an axis line in which the length of the gut surface 14 is the longest in the direction orthogonal to the central axis C of the frame 12. Further, the long axis Y is an axis line in which the length of the gut surface 14 is the longest in a direction parallel to the central axis C of the frame 12, and coincides with the central axis C.

On the gut surface 14, the adjacent gut K in the major axis direction and the adjacent gut J in the minor axis direction are rectangular meshes M having a length l in the major axis Y direction and a length m in the minor axis direction. Forming a plurality of.

From the center point O of the gut surface 14, which is the intersection of the short axis X and the long axis Y, to the left side in the short axis X direction, a position that is ½ of the total length W of the short axis X of the gut surface 14, that is, the gut. Surface 1
The first boundary line P1 parallel to the major axis Y is set at the position of the end 14a on the left side of 4, and the major axis Y of the gut surface 14 and the first boundary line P are set.
The region sandwiched by 1 is the first region A1.

Further, from the center point O of the gut surface 14 to the right in the minor axis direction, at a position half of the total length W of the gut surface 14, that is, at the position of the right end portion 14b of the gut surface 14 along the major axis Y. The parallel second boundary line P2 is set, and the region sandwiched between the major axis Y of the gut surface 14 and the second boundary line P2 is the second boundary region A.
Set to 2.

In the present invention, the gap between the guts K in the major axis Y direction is made different between the first region A1 which is the region on the left side of the gut surface 14 and the second region A2 which is the region on the right side. It is asymmetrical with respect to.

The average value of the lengths of the meshes M existing in the first area A1 in the short axis X direction is m _1, and the average value of the lengths of the meshes M existing in the second area A2 in the long axis Y direction is m. _Set to ₂ . The mesh M extending over both the first area A1 and the second area A2 is assumed to be present in an area to which more than half of the area belongs.

In the present invention, the smaller _{one of} the average values m ₁ and m ₂ , that is, the one in which the gaps between the guts K in the major axis Y direction are close, or the one in which the value is greater, that is, in the major axis direction Y, is used. The ratio of the gut K to the one with a sparse interval (average value m _{2 in} the case of FIG. 1) is set to 0.2 or more and 0.9 or less. In the case of FIG. 1, the gaps between the guts K in the major axis Y direction are closer in the first area A1 than in the second area A2, and m ₁ <m ₂
Therefore, 0.2 ≦ m ₁ / m ₂ <0.9.

As described above, in the racket 11 of the present invention, since the gut pattern is set to be bilaterally asymmetric with respect to the major axis Y, the distribution of the surface pressure of the gut surface 14 is also bilaterally asymmetric with respect to the major axis Y. . Therefore, with the racket 11 of the present invention, even a player who tends to hit on the left side or the right side of the gut surface 14 can obtain good resilience, spinnability, and controllability, and the surface on which the ball is hit is By changing it, it is possible to obtain the repulsion characteristic according to the situation.

In the racket 11 of the present invention, since the surface pressure distribution is asymmetrical as described above, the gut surface 14
The resilience, control performance, and spin performance are different when hit in the first area A1 and when hit in the second area A2.

That is, in FIG. 1, in the first area A1 where the gaps between the guts K in the long axis Y direction Y are closely set, the surface pressure is high, and therefore controllability is good when hitting in the first area A1. On the other hand, since the surface pressure is low in the second area A2 in which the interval between the guts K in the major axis Y direction is set to be sparse, when hitting in the right area A2, the resilience performance is good and the deformation of the guts J and K is good. Since the amount is large, the friction between the ball and the guts J and K is large, and the spin property is good. Therefore,
In the racket 11 of the present invention, when hitting on the right side or the left side of the gut surface, the racket 11 can be hit by changing the direction of the racket 11 with respect to the flight direction of the ball,
Repulsion performance and spin property can be made different.

For example, in the case of a player who tends to hit on the left side of the gut surface 14, one surface 1 of the racket is arranged so that the ball comes from the direction of arrow A in FIG. 1 (A).
If the racket 11 is gripped so that the ball 1a faces the direction of flight of the ball, the ball is hit in the first area A1 where the surface pressure is high, so that the controllability is good. On the other hand, this player makes the ball 11 come from the direction of arrow B in FIG.
If the racket 11 is gripped so that the ball is directed in the direction of flight of the ball, the ball is hit in the second area A2 having a low surface pressure, so that the resilience and the spin property are good.

3 and 4 show an embodiment of the present invention. The racket 11A according to the first embodiment is a tennis racket, and is used with a gut stretched on the gut tension portion 12a of the frame 12.

In the present embodiment, the gut tension portion 12a of the frame 12 is provided with guts J ₁ , J ₂ , ... J ₁₈ , J in the direction of the short axis X.
₁₉ horizontal for string holes a ₁ for tensioning _{a, a 2 ... a 18, a} 19
The is provided and _{b 1, b 2 ... b 18} , b 19. Here, the lateral gut holes a ₁ , a ₂ ... a ₁₈ , a ₁₉ and the lateral gut holes b ₁ , b ₂ ...
Holes with the same subscript of b ₁₈ and b ₁₉ face each other in the direction of the minor axis X, and one gut J ₁ , J ₂ ... J ₁₈ , J ₁₉ is inserted therethrough.

Further, the gut tension portion 12a of the frame 12
, Vertical gut holes c ₁ , c ₂ ... C ₁₃ , c ₁₄ and d for tensioning guts K ₁ , K ₂ , ... K ₁₃ , K ₁₄ in the long axis Y direction.
₁ , d ₂ ... d ₁₃ , d ₁₄ are provided. Here, the vertical gut holes c ₁ , c ₂ ... C ₁₃ , c ₁₄ and the vertical gut holes d ₁ , d ₂ ...
Holes with the same subscript of d ₁₃ and d ₁₄ face each other in the longitudinal direction and one gut K ₁ , K ₂ ... K ₁₃ , K ₁₄ is inserted therethrough.

The stretched guts J ₁ , J _2, ... J ₁₈ , J ₁₉ ,
The total length W of the gut surface 4 formed by K ₁ , K ₂ ... K ₁₃ , K _{14 in} the short axis X direction is 240 mm, and the total length L in the long axis Y direction is 320.
mm.

In this racket 11A, the gap between the end portion 14d of the gut surface 14 on the side of the top portion 12b and the gut J ₁ , the gap between the adjacent guts J ₁ , J ₂ ... J ₁₈ , J ₁₉ in the minor axis direction, and The lateral gut holes a ₁ , a ₂ ... a ₁₈ , a ₁₉ and b ₁ , so that the distance between the gut J ₁₉ and the end portion 14e of the gut surface 4 on the side of the yoke portion 12c becomes the distance shown in Table 1, respectively.
a b ₂ ... b _18, b ₁₉ are arranged.

[0025]

[Table 1]

In this racket 1A, the gut surface 4
Between the left end 4a and the gut K ₁ , the interval between the adjacent longitudinal guts K ₁ , K ₂ ... K ₁₃ , K ₁₄ , the gut K
The distance between ₁₄ and the right end 4b of the gut surface 4 is shown in Table 2 below.
The vertical gut holes c ₁ , c ₂ ...
c ₁₃ , c ₁₄ and d ₁ , d _2, ... D ₁₃ , d ₁₄ are arranged.

[0027]

[Table 2]

In the racket 1A of this embodiment, the gut surface 1
4 on both sides in the direction of the short axis X from the center point O of 4, the position of 1/2 of the total length W of the short axis X of the gut surface 14, that is, the gut surface 14
A boundary line P1 and a boundary line P2 parallel to the long axis Y are set at the positions of the left end 4a and the right end 4b of the long axis Y, respectively.
If the region sandwiched between the first boundary line P1 and the first boundary line P1 is the left region A1, and the region sandwiched between the long axis Y and the second boundary line P2 is the right region A2, the short axis X of the mesh M existing in the first region A1. The average value m ₁ of the lengths in the directions is 13.39, and the average value m ₂ of the lengths of the meshes M existing in the second region A2 in the short axis X direction is 19.17.
Is. Therefore, in this embodiment, the ratio with respect to the average value m _1, the average value the average value m ₂ of the larger m ₁ the smaller of m ₂ (m ₁ / m ₂₎ is 0.72.

Since the racket 1A of this embodiment has the gut pattern as described above, the first area A of the gut surface 4 is formed.
In 1, the gap between the guts K in the major axis Y direction is close and the surface pressure is high, while in the second region A2, the gut K in the major axis Y direction is high.
And the surface pressure is low. FIG. 6 shows the surface pressure of the racket 1A of the first embodiment measured by the measuring device of FIG. 5 (A).

In FIG. 5 (A), 20 is a universal compression / tensile tester, in which a cylindrical jig 22 having a diameter of 22 mm is attached to the tip of a load frame 21 which moves vertically. In the racket 11A, the gut tension portions 12a of the frame 12 are fixed on the fixed base 13 at eight places.

The load frame 21 is moved downward in the figure, and the jig 22 is pressed against the gut surface 14 so that the gut surface 1
The reaction force value of 4 is detected by the load cell 24. The detected reaction force value and the displacement of the jig 22 from the state in which the gut surface 14 is in contact with the gut surface 14 with a reaction force of 0 are transferred via the controller 25 to the XY direction.
Input to the printer 26, and as shown in FIG. 5B, a diagram in which the horizontal axis is the displacement and the vertical axis is the reaction force is obtained.

FIG. 6 shows the surface pressure (the reaction force when the gut surface 4 is displaced by 5 mm) when the distance from the left end 14a on the short axis X is changed. The gut tensioned the warp yarn at 55 pounds and the weft yarn at 44 pounds.

As is apparent from FIG. 6, in the racket 1A of the embodiment, the surface pressure is about 20 kg near the left end 14a of the gut surface 14, and about 20 kg near the central portion 14c of the gut surface 14. The surface pressure is about 17 kg near the end 14b on the right side of 15 kg.

Thus, the racket 11A of the first embodiment.
Then, the surface pressure is relatively high in the first area A1 on the left side of the gut surface 14, while the surface pressure is relatively low in the second area A2 on the right side. Therefore, when hit in the first area A1, the controllability is good. On the other hand, in the second region A2, the resilience and spin properties are good.

[0035]

Experimental Example An experiment was conducted to confirm the effect of the present invention. As a comparative example, the conventional racket 11B shown in FIG.
(Dunlop DP-80 manufactured by Sumitomo Rubber Industries, Ltd.) was prepared.

This racket 11B has guts J ₁ , J ₂ ... J ₁₈ , J ₁₉ in the short axis X direction and guts K ₁ , K _{2 in the} long axis Y direction.
... K ₁₅ and K ₁₆ are stretched, the total length W of the gut surface 14 in the short axis X direction is 240 mm, and the total length L in the long axis X direction is 320.
mm.

In this racket 1B, the gap between the end 4d of the gut surface 14 on the top portion 12b side and the gut J ₁ , the gap between adjacent guts J ₁ , J ₂ ... J ₁₈ , J ₁₉ in the minor axis direction, and Gut J ₁₉ and the end 4 of the gut surface 4 on the side of the yoke portion 12c
The distance from e is set to the distance shown in Table 3.

[0038]

[Table 3]

In this racket 1B, the gut surface 1
4 of the left end portion 14a and the spacing between the gut K _1, the spacing between the gut K ₁ of the adjacent _{longitudinally, K 2 ... K 15, K} 16, right end portion 4b of the gut K ₁₆ and gut surface 14 The distance between them is set to the distance shown in Table 4 below.

[0040]

[Table 4]

In the racket 11B of the comparative example, the gut surface 4
The first boundary line P1 and the second boundary line P2 parallel to the long axis Y are set at the positions of the left k end 4a and the right end 4b, respectively, and are sandwiched between the long axis Y and the first boundary P1. Letting the region be the left region A1, and the region sandwiched between the long axis Y and the second boundary line P2 be the right region A2, the length of the mesh M in the first region A1 and the second region A2 in the short axis X direction The average values m ₁ and m ₂ are both 13.89, and the ratio (m ₁ / m ₂ ) is 1.00.

The surface pressure of the racket 11B of the comparative example is shown in FIG.
The results measured by the device shown in (A) are as shown in FIG. As shown in FIG. 8, the racket 11B of the comparative example.
Then, the surface pressure of the gut surface 14 is distributed symmetrically with respect to the major axis Y.

In this experiment, 20 top-level amateur players used the racket 11A of the example and the racket 11B of the comparative example to obtain 20 balls for each of the first area A1 and the second area A2 of the gut surface 14. Thirty balls were hit, and three grades of "normal", "good" and "bad" were evaluated for resilience, control performance and spin performance. A nylon gut was used as the gut, and the warp was stretched at 55 pounds and the weft was stretched at 44 points. The experimental results are as shown in Tables 5 and 6.

[0044]

[Table 5]

[0045]

[Table 6]

From Table 5 above, when hitting in the first area A1, the racket 11A of the embodiment sets the surface pressure of the first area A1 to be high, so that the racket 11B of the comparative example has better control performance. Can be confirmed to be good. Further, from Table 6 above, when hitting in the second area A2, the racket 11A of the example sets the surface pressure of the second area A2 to a low value, so that the racket 11B of the comparative example has a higher resilience performance and spin. It can be confirmed that the performance is good.

A repulsion test was conducted on the racket 11A of the example and the racket 11B of the comparative example. In this repulsion test, as shown in FIG. 9, the velocity of the tennis ball 20 bounced by colliding the rigid tennis ball 20 having an initial velocity V ₀ against the gut surface 14 of the racket 11A of the example and the racket 11B of the comparative example. Vr was measured. The coefficient of restitution is represented by the following equation (1).

(Repulsion coefficient) = Vr / V ₀ (1)

The results of the repulsion test are shown in FIG. From FIG. 10, when hitting in the second area A2, the racket 1A of the second embodiment of the present invention sets the surface pressure of the second area A2 to a low value, and thus the racket 1B of the embodiment is Good resilience in comparison.

[0050]

As is apparent from the above description, in the racket of the present invention, the first boundary line and the second boundary line which pass through the ends of the gut surface in the minor axis direction and are parallel to the major axis are set. The average value of the mesh lengths in the short axis direction in the first region, which is the region sandwiched between the long axis of the gut surface and the first boundary line, and the region sandwiched between the long axis and the second boundary line. Of the average value of the length of the mesh in the minor axis direction in the second area, the ratio of the average value of the smaller value to the average value of the larger value is 0.2 or more and 0.9 or more.
It is set below. Therefore, in the racket of the present invention, the surface pressure distribution on the gut surface becomes asymmetrical with respect to the major axis, and the part with good resilience and spin performance and the part with good controllability are not the central part of the gut surface but the long part. Since it exists in a position that is displaced to the left or right with respect to the axis,
Even a player who tends to hit on the left side or the right side of the gut plane can obtain good resilience.

[Brief description of drawings]

FIG. 1 is a partial front view showing a racket of the present invention.

FIG. 2A is a side view of the racket, and FIG. 2B is a front view of the racket.

FIG. 3 is a partial front view showing the racket of the embodiment.

FIG. 4 is a partial front view showing the racket of the embodiment.

FIG. 5A is a schematic view showing a surface pressure measuring device,
(B) is a schematic diagram showing the output of the XY recorder.

FIG. 6 is a graph showing the relationship between the distance from the left end and the surface pressure in the example.

FIG. 7 is a partial front view showing a racket of a comparative example.

FIG. 8 is a graph showing the relationship between the distance from the left end and the surface pressure in the comparative example.

FIG. 9 is a schematic view showing a method of a repulsion test.

FIG. 10 is a diagram showing the results of a repulsion test.

FIG. 11 is a schematic diagram for explaining a gut surface.

[Explanation of symbols]

 11, 11A, 11B Racket 12 Frame 12a Gut tension part A1 1st area A2 2nd area J, K Gut M Mesh P1 1st boundary line P2 2nd boundary line X Minor axis Y Major axis

Claims (1)

[Claims] 1. The minor axis (X) of each gut surface (14)
The first boundary line (P1) and the second boundary line (P2) that pass through the end portions (14a, 14b) in the direction and are parallel to the long axis (Y) are set, and the long axis ( Y) and the first boundary line (P
The region sandwiched by 1) is the first region (A1), and the region sandwiched by the major axis (Y) and the second boundary line (P2) is the second region (A2).
And the short axis (X) direction of the mesh (M) formed by the intersection of the gut (K) in the major axis (Y) direction and the gut (J) in the minor axis (X) direction in the first area (A1). and the length of the average value (m _1), different values of the minor axis (X) direction of the length of the average value of the mesh (M) in the second region (A2) (m _2), and the Of the average values (m ₁ , m ₂ ) of the length of the mesh (M) in the short axis (X) direction, the ratio of the average value of the smaller value to the average value of the larger value (m ₁ / m _2). ) Is set to 0.2 or more and 0.9 or less, a racket.