JP2002191723A - Racket frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a racket frame which can provide an excellent repulsiveness and controlling property while ensuring a favorable operability by greatly expanding the sweet area without expanding the area of the ball-hitting section. SOLUTION: A window hole 8 which penetrates the internal and external peripheral surfaces of the ball hitting section is provided at least at one region of the ball hitting section. Then, a gut-supporting body 10 is supported and fixed in the window hole 8 in such a manner that the gut-supporting body 10 may activate swinging in the ball-hitting direction by following the warpage of the gut at the time of hitting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a racket frame (hereinafter, simply referred to as a racket frame) used in ball games such as tennis, and more particularly, to a gut tension provided on a hitting portion of a racket frame. The support structure was devised.

[0002]

2. Description of the Related Art Conventionally, racket frames have been formed using materials such as wood and metal. However, at present, various characteristics such as toughness, rigidity and repulsion required for racket frames are satisfied. In addition, since there is a large degree of freedom in designing such that a required shape can be easily obtained, a racket frame made of fiber reinforced resin has come to occupy the mainstream.

[0003] Normally, if described as an example racket frame for tennis, the area of the hitting portion of this type of racquet frame are generally those 500cm ² ~900cm ^2, also the gut Zhang設前Weight is 200g-33
Most are about 5 g. Also, as its configuration,
As shown in FIG. 11 and FIG. 12, the hitting portion 21, the shaft portion 22, and the grip portion 23 have a tubular structure composed of an outer shell layer 24 made of fiber reinforced resin. The ball hitting portion 21 of the frame 25 has a large number of gut insertion holes 28 penetrating the outer peripheral surface 26 and the inner peripheral surface 27. A gut protection groove 29 is recessed on the outer peripheral surface 26 of the hitting portion 21, and the gut protection groove 29 and the gut insertion hole 28 are inserted into the gut protection groove 29 and each gut insertion hole 28. Hole 2
Gut protection member 30 having a base portion and a cylindrical portion fitted into
Is mounted, and a gut 31 made of a material such as nylon, sheep, or whale muscle is inserted into the cylindrical portion of the gut protection member 30 to form a striking surface 32.

[0004] In general, racket frames 25
Is formed by inserting a gut 31 into a gut insertion hole 28 formed so as to penetrate the inner and outer peripheral surfaces of the ball hitting portion 21 so that the hitting surface 3
As shown in FIG. 13, when hitting the ball 33, the gut 31 stretched in a substantially straight line between a pair of opposing frames of the hitting portion 21 pushes the ball 33 when hitting the ball. Under the pressure F, it bends starting from the opening end 34 of the gut insertion hole 28 that opens to the inner peripheral surface 27 side of the hitting portion 21,
Subsequently, the operation of rebounding is exhibited.

Considering the deflection of the gut 31 at the time of hitting the ball, if the ball 33 is hit in a substantially central area of the hitting portion 21 usually called a sweet area,
The distance L1 from the strike point P to the opening end 34 of the gut insertion hole 28 is equal to the opening end 34 of one of the opposing gut insertion holes 28.
Is substantially equal to the distance L2 to the opening end 3
The deflection angles θ1 and θ2 of the gut 31 that bends starting from 4 are equal on both sides, and when the gut 31 receives a pressing force F of the ball 33 and is greatly bent at the time of impact, while giving a good repulsive force to the ball 33 The ball 33 can be accurately bounced back in the same direction as the pressing direction, that is, in the direction perpendicular to the hitting surface 32.

On the other hand, when the ball 33 is hit at a position outside the central area (hit point Pn), as shown in FIG. 14, the distance from the hit point Pn to the opening end 34 of the gut insertion hole 28 is increased. Due to the large difference between the distance L1 and the distance L2 to one of the opposing open ends 34,
The bending angles θ1 and θ2 of the gut 31 that bends starting from the opening end 34 are greatly different. As a result, the direction of the return ball with respect to the pressing direction of the ball 33 at the time of impact is
The ball 3 is deviated by the inclination angle θn determined by the two different deflection angles θ1 and θ2, and moves in the direction intended by the player.
This makes it difficult to return the ball 3 and, at the same time, the amount of flexure t of the gut 31 also decreases, which exacerbates problems such as reduced resilience and shot feeling.

In general, the deflection angles θ1, θ2 of the gut 31, which differ depending on the position of the hitting point Pn, and
The deviation in the returning ball direction is caused by the gut 31
Is greatly affected by the length of the tension. In other words, since the gut 31 bends starting from the opening end 34 of the gut insertion hole 28 formed in the hitting portion 21, the opening end of the gut insertion hole 28 serving as a starting point of such bending of the gut 31. 34, the difference in the bending angles θ1 and θ2 of the gut becomes smaller geometrically,
The bias in the returning ball direction is reduced. That is, the sweet area of the hitting portion 21 is increased.

Conventionally, in view of such circumstances, various attempts have been made to increase the length of the gut 31 extended on the hitting portion 21 in order to enlarge the sweet area. ing. For example, the length of the gut is designed to be longer by increasing the area of the hitting portion by about 20% to 30% as compared with a conventional one, such as a so-called "decalake" or "large" racket frame. Known to do so.

[0009] Further, as disclosed in Japanese Utility Model Laid-Open Publication No. 63-20864, as shown in FIG.
A configuration in which the recess 35 is provided in the frame circumferential direction, or
As disclosed in Japanese Utility Model Application Laid-Open No. 63-20867, as shown in FIG. 16, the opening of the gut insertion hole 28 that opens on the inner peripheral surface 27 side of the hitting portion 21 is expanded toward the front and back sides in the hitting direction. With the configuration, the gut 31 at the time of impact is provided.
The deflection fulcrum Q of the gut, which is the starting point of the deflection of the gut, is shifted toward the outer peripheral surface 26 of the hitting portion 21, and the length of the gut 31 is lengthened by the shift of the deflection fulcrum Q, thereby enlarging the sweet area. A proposal to achieve this is known.

[0010]

However, such conventionally known racket frames have the following drawbacks. In other words, in a racket frame with an increased area of the hitting portion, the mass of the racket frame itself and the wind pressure area at the time of swing are inevitably increased with the increase of the area of the hitting portion. There was a drawback that the swingability was poor, making it difficult to cope with high-speed play.

Further, as proposed in Japanese Utility Model Application Laid-Open No. 63-20864 or Japanese Utility Model Application Laid-Open No. 20867/1988, a gut displacement fulcrum Q, which is a starting point of the deflection of a gut at the time of impact, is located on the outer peripheral surface side of the hitting portion. In the racket frame that is configured to shift to, the gut extension length can be increased by the shift of the displacement fulcrum Q without increasing the area of the hitting portion, so that the sweet area is increased accordingly. Can be achieved. However, the displacement of the displacement fulcrum Q is
For example, as shown in FIG.
It is expected that the sweet area which can be expanded is only a small amount within the front thickness T of the hitting portion, such as the depth of the concave portion 35 provided on the side, and the area of the sweet area that can be enlarged is small. Anyway,
In a wide area except for the center area of the hitting portion of the racket frame, a large deviation still occurs in the ball returning direction at the time of hitting, and the amount of deflection t of the gut is greatly reduced, so that resilience and hitting are achieved. There is a problem that the feeling is remarkably reduced. Therefore, in order to secure a sufficient sweet area even in this type of racket frame, the area of the hitting portion must be increased, but in this case, the mass of the racket frame and the wind pressure area increase as described above. As a result, there arises a problem that the swing-out property is deteriorated.

[0012] As described above, conventionally, the required characteristics for obtaining stable controllability, good resilience and shot feeling, and ensuring good operability, by enlarging the sweet area of the racket frame are mutually different. At present, it is difficult to obtain a racket frame that has conflicting design configurations and can sufficiently satisfy both of these requirements.

The inventor of the present invention has conducted various experimental studies and conducted intensive studies in order to obtain a racket frame capable of ensuring good operability while enlarging the sweet area of the racket frame. As shown in FIG. 2, in the conventional racket frame, since the displacement fulcrum Q of the gut 31 is always located on the hitting surface 32, the length between the displacement fulcrums Q (the distance L between the open ends 34 of the gut insertion holes 28) is reduced. )
It is limited to within the opposing frame of the hitting portion 21. That is, there is a limit in designing a longer length between the displacement fulcrums Q without expanding the hitting ball portion 21, and expansion of the sweet area is limited. However, as shown in FIG.
If the displacement fulcrum Q of the gut 31 located on the striking surface 32 shifts in a direction perpendicular to the striking surface 32 with the deflection of the gut 31 when hitting the ball, the gut 31 is indicated by a virtual point Qn. A racket frame having a displacement fulcrum Q at a point, that is, a racket frame in which the area of the hitting portion 21 is large and the length between the displacement fulcrums Q (the distance L between the open ends 34 of the gut insertion holes 28) is long. Is obtained,
As a result, it has been found that the sweet area can be greatly expanded without expanding the hitting portion 21.

The present invention has been made in view of the above-mentioned conventional problems, and by enlarging the sweet area without enlarging the area of the hitting portion, it is possible to obtain excellent resilience while ensuring good operability. And a racket frame capable of providing controllability.

[0015]

In order to achieve the above object, the present invention has the following arrangement. That is, in the racket frame according to claim 1 of the present invention, in a racket frame including a hitting portion, a grip portion, and a shaft portion connecting the hitting portion and the grip portion, at least a part of the hitting portion is provided. In addition, a window hole penetrating through the inner and outer peripheral surfaces of the hitting portion is provided around the hitting portion, and a gut support having a plurality of gut insertion holes in the window hole hits the ball by the stress transmitted from the gut at the time of hitting. Characterized in that they are arranged so as to excite rocking in a direction.

A second aspect of the present invention is the racket frame according to the first aspect, wherein the gut support is held by an elastic body supported and fixed in a window hole. It is.

According to a third aspect of the present invention, there is provided the racket frame according to the first or second aspect, wherein the window hole is located near a central portion in a major axis direction of the hitting portion or a short hole orthogonal to the major axis direction. It is provided in at least a part of a region corresponding to the vicinity of the central portion in the axial direction.

A fourth aspect of the present invention is the racket frame according to the first, second, or third aspect, wherein the window hole is provided over an area of 10% to 60% of the entire circumference of the hitting portion. It is characterized by having.

[0019] Claim 5 is claim 1, 2, 3 or
4. The racket frame according to 4, wherein the elastic body supported and fixed in the window hole is made of rubber or elastomer.

Claim 6 is the above-mentioned claim 1, 2, 3, or
4. The racket frame according to 4, wherein the elastic body supported and fixed in the window hole is made of a spring material.

The seventh aspect is the first aspect, the second aspect, the fourth aspect,
5 or, a racket frame according to 6, the area of the hitting portion of the racquet frame, 500 cm ² to 900
cm ² .

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to preferred embodiments described in detail with reference to the drawings. FIG. 1 is an external view showing the front and side surfaces of the racket frame of the present embodiment.
3 is an enlarged end view taken along the line AA of FIG. 1, and FIG. 3 is an enlarged explanatory view of the portion C of FIG.

That is, the racket frame 1 of this embodiment is
As shown in FIG. 1, a hitting portion 4 in which a gut 2 is stretched to form a hitting surface 3, and two left and right shaft portions 6 connecting the hitting portion 4 and the grip portion 5 are made of a fiber-reinforced resin. Has a tubular structure integrally formed by The weight of the racket frame 1 before the gut is stretched is 200 g to 3 g.
It is in the range of 35 g, and the size of the hitting ball portion 4 is approximately 500 cm ² , which is almost the same as a conventional general racket frame.
It is configured within the range of 900 cm ² .

In the racket frame 1 of the present embodiment,
As shown in FIGS. 1 to 3, a region near the center of the hitting portion 4 in the long axis y direction (when the hitting portion 4 is projected from the front,
When the top part 7 of the hitting part 4 is set to 12:00, 12:00 and 6
A comparative example in which the inner and outer peripheral surfaces of the hitting ball portion 4 penetrate the inner peripheral surface of the hitting portion 4 in a near-region corresponding to the time (hour) and a region near the center in the direction of the short axis x perpendicular to the direction of the long axis y (neighboring region corresponding to 3:00 and 9:00). A large window hole 8 is provided around, and a gut support 10 having a plurality of gut insertion holes 9 is held and fixed in the window hole 8 by an elastic body 11 made of rubber, elastomer, or the like. Configuration.

That is, as shown in FIG. 2, the gut support 10 formed so as to have a width Wg smaller than the width Wm of the window hole 8, as shown in FIG.
The elastic member 11 is supported and fixed on the inner wall surface 12 of the window hole 8 so as to excite the swing following the deflection of the window hole 8.

The racket frame 1 of the present embodiment as described above
Then, as shown in FIG. 6, when the pressing force from the ball 13 is applied to the gut 2 at the time of hitting the ball, the gut support 10 swings in the pressing direction, and the displacement fulcrum Q of the gut 2 is moved to the gut support 10. A shift occurs in the pressing direction by the amount of the swing.
As a result, the gut 2 exhibits the same bending as the case where the gut 2 bends with the point indicated by the virtual point Qn shifted to the outside of the displacement fulcrum position before hitting the ball as a fulcrum. A large sweet area larger than the sweet area specified by L is obtained.

Further, as shown in FIG. 7, when the ball 13 is hit at a position deviating from the central region (hitting point Pn), the gut support 1 near the hitting point Pn is hit.
Oa excites a larger swing than the opposing gut support 10b, and the displacement fulcrum Q of the gut 2 causes a correspondingly large displacement in the pressing direction. As a result, the virtual point Qna of the deflection of the gut 2 is set to the opposite gut 2
The deflection angle θ of the two guts 2 is shifted to the outside more than the virtual point Qnb of the deflection of the gut 2.
1, θ2 appear substantially equal, the deflection of the ball 13 in the returning direction is reduced, and the bending amount t substantially the same as when the ball 13 is hit in the center region is obtained.

Although the shape and size of the window hole 8 provided in the hitting portion 4 vary depending on the cross-sectional shape of the racket frame itself, the shape of the gut support 10, and the like, the racket frame 1 is practically used. As a result of conducting many experiments on the premise that the swing range of the gut support 10 is sufficiently ensured while achieving the necessary strength and rigidity, the width Wm of the window hole 8 was found to be equal to the side width of the hitting portion 4. Wf
The width is preferably 20% to 60%, more preferably 25% to 50% of (the width in the direction orthogonal to the hitting surface 3). When the width Wm is smaller than 20%, there occurs a problem that a swing range in the hitting direction of the gut support body 10 held and fixed in the window hole 8 cannot be sufficiently secured, and If the width Wm is larger than 60%, there is a possibility that the strength and rigidity of the frame in this portion are insufficient and the striking face 3 becomes unstable.

The length Lm of the window hole 8 is 15
It is preferable that the distance be set in the range of mm to 100 mm. In addition, from various experiments, if the length L of the window hole 8 is excessively long, a twisting behavior occurs in the hitting portion 4, and particularly, in a case where the ball is hit with a high-speed swing such as an intermediate or advanced player. It has been found that the ball striking surface 3 is twisted and not stable, so that the controllability and resilience as well as the feel at impact are impaired. Therefore, the window hole 8 does not continuously extend in the circumferential direction of the hit portion 4,
The length Lm is set in the range of 15 mm to 100 mm, especially 20 mm to 50 mm. As shown in FIG. It is configured to be provided independently in the neighborhood area corresponding to 3 o'clock and 9 o'clock where the gut is long stretched,
The area corresponding to 12:00 and 6:00 of the hitting ball portion 4
As shown in FIG. 5, the corner 14 region sandwiched between the regions corresponding to the hours and 9 o'clock has a configuration in which the window hole 8 is not formed as shown in FIG. It is desirable.

The width Wg of the gut support 10 is configured to have a width slightly larger than the diameter of the gut insertion holes 9 formed in a large number in the gut support 10. Further, in order to sufficiently secure the swing range of the gut support 10 within the width Wm region of the window hole 8, the width Wg of the gut support 10 is 40% of the width Wm of the window hole 8. ~ 60%, specifically 4mm ~ 6mm
Is desirably set within the range.

The racket frame 1 of the present embodiment as described above
In order to manufacture, for example, around a tube for internal pressure molding, a plurality of prepreg sheets for racket frame molding are laminated, and after arranging this in a cavity having a mold frame shape, In a normal manufacturing method of a racket frame made of fiber reinforced resin, in which compressed air or the like is injected and heated, as shown in FIG. In a region corresponding to 3 o'clock and 9 o'clock, a molded product 15 having a relatively large window hole 8 penetrating the inner and outer peripheral surfaces is formed, and then, as shown in FIG. Gut support 1 having a plurality of gut insertion holes 9 in holes 8
The elastic body 11 holding and fixing the elastic body 11
Is formed by adhesively fixing one side to the inner wall surface 12 of the window hole 8. In addition to the above method, although not shown, the gut support 10 is previously held in the area corresponding to 12:00 and 6 o'clock and 3 o'clock and 9 o'clock of the hitting portion 4 at the time of molding the molded body 15. It is also possible to provide a method in which the elastic body 11 that is held and fixed is provided, and is integrally molded in a mold. The gut support 10 and the elastic body 11 may be fixed to each other by a method of bonding and fixing with an adhesive or a method of integrally bonding and fixing simultaneously with molding, such as two-color molding.

As the main reinforcing fibers constituting the racket frame 1 made of the fiber-reinforced resin of the present embodiment, various types such as carbon fiber, glass fiber, boron fiber and aromatic polyamide fiber can be used. Carbon fibers are also preferable in terms of rigidity, mass and cost. As the matrix resin, an epoxy resin, a nylon resin or the like can be used, but an epoxy resin is preferable in view of strength and durability.

The material constituting the elastic body 11 is preferably a soft material having excellent formability (handlability) by maintaining the shape retention of the material itself and having a small difference in hardness due to a temperature change from a low temperature to a high temperature. . As an example of a preferable material, for example, it is formed of an elastic material such as a styrene-based elastomer, a polyester elastomer, a PVC-based elastomer, EVA, EPDM, a thermoplastic polyurethane elastomer, a polyethylene elastomer, a polyamide elastomer, or a viscoelastic material. preferable. Among them, those having a hardness of 20 to 90 in JIS-D hardness are preferable. The hardness of the material is J
If the hardness is less than IS-D hardness 20, it is difficult to support the gut 2 which is stretched with high tension. If the hardness is greater than JIS-D hardness 90, the gut 2 may be bent at the time of impact. Following this, it becomes difficult for the gut support body 10 to excite the swing in the hitting ball direction, and the sweet area cannot be sufficiently expanded.

The gut support 10 is made of a material which has good adhesion to the material forming the elastic body 11, is lightweight, and supports the gut 2 which is stretched with high tension. It is desirable to use a material having rigidity to maintain sufficient shape retention. For example, as an example, a cured molded product of a fiber reinforced resin material using carbon fiber or glass fiber as a reinforcing material, or an injection molded product made of a material such as a nylon resin, an ABS resin, a polypropylene resin, a vinyl chloride resin, and the like. Can be

As described above, in the racket frame 1 of the present embodiment, an example has been described in which the window holes 8 are provided at four locations corresponding to the hitting portion 4 at 12:00 and 6:00, and at 3:00 and 9:00. However, the present invention is not limited to this, and the number and location of the window holes 8 can be arbitrarily selected.
At this time, the window hole 8 is 10% to 60% of the entire circumference of the hitting portion 4.
%, Especially 20% to 40%. If the area of the window 8 is smaller than 10% of the entire circumference of the hitting portion 4, it is difficult to sufficiently expand the sweet area, and if it is larger than 60%, the hitting portion 4 is hit at the time of hitting the ball. Is likely to be twisted, resulting in a disadvantage that the hitting surface 3 is not stable.

Further, in the above embodiment, an example is shown in which a material such as rubber or elastomer is used as the elastic body 11 provided in the window hole 8, but the present invention is not limited to this.
For example, as shown in FIGS.
It is also possible to adopt a configuration in which 0 is held and fixed by a plurality of spring members 16. As the spring member 16, a leaf spring or the like can be suitably used in addition to the coil spring shown in the figure.

[0037]

EXAMPLES In order to confirm the effects of the present invention, the following Table 1 was used.
The racket frames of Example 1 and Comparative Examples 1 to 3 shown in FIG.

[0038]

[Table 1]

That is, the racket frame 1 prepared as the first embodiment is similar to the above-described embodiment in that the
Window holes 8 are formed in the regions corresponding to 2 o'clock and 6 o'clock and 3 o'clock and 9 o'clock, and a gut support 10 is
1 and has a configuration in which the window hole 8 is fixed.
Has a width Wm of 10 mm and a length Lm of 60
mm, 50 mm at 6 o'clock, 80 at 3 o'clock and 9 o'clock
mm, and the ratio of the window hole 8 to the entire circumference of the hitting portion 4 was 30%. The gut support 10 is made of a nylon resin, and has a width Wg of 5 mm and a length substantially equal to the length of each window hole 8. The elastic body 11 was made of an elastomer resin.

As Comparative Example 1, a racket frame having the above-mentioned structure without the window hole 8 was prepared. The area of the hitting portion of the racket frame of Comparative Example 1 was substantially the same as the racket frame of Example 1 described above.

As Comparative Example 2, the above Comparative Example 1 was used.
Similarly to the above, a racket frame having no window hole 8 as in Example 1 and having a large hitting portion area was prepared.

In Comparative Example 3, the window hole 8 of the racket frame of Example 1 was extended in the circumferential direction so that the ratio of the window hole 8 to the entire circumferential length of the hitting portion 4 was 70%. Except for the configuration, a configuration substantially the same as that of Example 1 was prepared.

An actual hitting test was performed on the racket frames of Example 1 and Comparative Examples 1 to 3. In this actual hit test, the ball was hit with the racket frames of Example 1 and Comparative Examples 1 to 3 for a large number of intermediate and advanced players, and the operability of the racket frame felt by the player at that time. (Ease of swinging out), resilience at the time of hitting, controllability, and feeling of discomfort during play were evaluated. The test results at this time are shown in Table 2 below.

[0044]

[Table 2]

From the above test results, the racket frame of the first embodiment can provide excellent resilience and controllability as compared with the racket frames of Comparative Examples 1 to 3, and have excellent operability. It was confirmed that the racket frame did not give a feeling of strangeness during play.

[0046]

As described above, according to the present invention, at least a part of the hitting portion is provided with a window hole penetrating the inner and outer peripheral surfaces of the hitting portion, and the gut support when hitting the gut support is provided in the window hole. Since it is configured to be supported and fixed so as to excite the swing in the hitting ball direction following the deflection of the ball, the sweet area can be greatly expanded without increasing the area of the hitting ball portion.
Therefore, at the time of impact, while good operability is obtained,
Excellent resilience, controllability and shot feeling can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the front and side surfaces of a racket frame according to the present embodiment.

FIG. 2 is an enlarged end view taken along the line AA of FIG. 1;

FIG. 3 is an enlarged explanatory view of a portion C in FIG. 1;

FIG. 4 is an explanatory diagram showing a swinging state of a gut support.

FIG. 5 is an enlarged end view taken along the line BB of FIG. 1;

FIG. 6 is an explanatory diagram showing a state where a ball is hit with the racket frame of the embodiment.

FIG. 7 is an explanatory diagram showing a state where a ball is hit with the racket frame of the embodiment.

FIG. 8 is an explanatory view showing a method of manufacturing the racket frame of the embodiment.

FIG. 9 is an explanatory diagram showing another embodiment.

FIG. 10 is an explanatory diagram showing another embodiment.

FIG. 11 is a front view of a conventional racket frame.

FIG. 12 is an explanatory diagram of a configuration of a DD line portion region in FIG. 11;

FIG. 13 is an explanatory diagram showing a state where a ball is hit with a conventional racket frame.

FIG. 14 is an explanatory view showing a state where a ball is hit with a conventional racket frame.

FIG. 15 is an explanatory diagram of a configuration of a conventional racket frame.

FIG. 16 is a configuration explanatory view of a conventional racket frame.

FIG. 17 is a conceptual diagram of bending of a gut.

[Explanation of symbols]

 Reference Signs List 1 racket frame 2 gut 3 hitting surface 4 hitting portion 5 grip portion 6 shaft portion 7 top portion 8 window hole 9 gut insertion hole 10 gut supporter 10a gut supporter 10b gut supporter 11 elastic body 12 inner wall surface 13 ball 14 corner Reference Signs List 15 molded product 16 spring material 21 hitting portion 22 shaft portion 23 grip portion 24 outer shell layer 25 racket frame 26 outer peripheral surface 27 inner peripheral surface 28 gut insertion hole 29 gut protection groove 30 gut protection member 31 gut 32 hitting surface 33 ball 34 opening End 35 recess

Claims (7)

[Claims] 1. A racket frame including a hitting portion, a grip portion, and a shaft portion connecting the hitting portion and the grip portion, wherein at least a part of the hitting portion has inner and outer peripheral surfaces of the hitting portion. And a gut support provided with a plurality of gut insertion holes in the window hole so as to excite rocking in a hit ball direction by stress transmitted from the gut at the time of hitting. A racket frame that is provided. 2. The racket frame according to claim 1, wherein the gut support is held by an elastic body supported and fixed in a window. 3. The window hole is provided in at least a part of a region corresponding to a vicinity of a central portion in a major axis direction of the hitting portion or a vicinity of a central portion in a minor axis direction orthogonal to the major axis direction. The racket frame according to claim 1 or 2, wherein: 4. The window hole has a diameter of 10% or more of the entire circumference of the hitting portion.
4. The racket frame according to claim 1, wherein the racket frame is provided over a 60% area. 5. The elastic body supported and fixed in the window hole,
The racket frame according to claim 1, 2, 3, or 4, wherein the racket frame is made of rubber or an elastomer. 6. The elastic body supported and fixed in the window hole,
The racket frame according to claim 1, 2, 3, or 4, wherein the racket frame is made of a spring material. Area 7. hitting portion of the racquet frame, according to claim 1, 2, 3, 4 or characterized in that it is a 500cm ² ~900cm ^2, racquet frame according 6.