JP3172453B2 - Racket frame - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a racket frame for ball games such as tennis, badminton, and squash.
More specifically, the present invention improves the arrangement of lead for weight balance attached to the shaft portion.

[0002]

2. Description of the Related Art In recent years, it has been desired to reduce the weight of a racket. By increasing the elasticity and strength of a fiber reinforced material, it has become possible to reduce the weight of a low frame of a racket made of a molded product of a fiber reinforced resin. ing. However, when the speed of the ball hitting the frame is high or during volley, if the weight of the racket is light, there is a problem that the ball is easily defeated, and the distortion applied to the racket has a large effect on the hitting surface. For this reason, the fiber reinforcing material is intensively arranged in the face portion surrounding the striking face, and the weight distribution on the face portion side inevitably increases, which is liable to be a so-called top heavy.

[0003] As described above, when it becomes a top heavy,
In order to balance the entire racket frame, as shown in FIGS. 5A and 5B, a dimension from the grip end E to a balance fulcrum position P (a fulcrum position for holding the racket frame horizontally). L (hereinafter, referred to as a balance dimension L) becomes longer. However, when the balance dimension L becomes longer, the moment of inertia with the fulcrum as the fulcrum during the swing increases, giving a heavy feeling to the player. In the drawing, T indicates a top portion of the face portion F surrounding the striking surface.

[0004] Therefore, in order to maintain the moment of inertia at the conventional level, a racket which has become a top heavy due to a reduction in weight is attached to a grip portion having a large specific gravity such as lead, so that the length L does not become large. Like that.

As shown in FIGS. 6A and 6B, a groove 1a is provided on the outer surface of a grip 1 of a low frame made of a fiber-reinforced resin, and lead 2 is inserted into the groove 1a. It is inserted and struck with a tax or a nail 3 to secure the weight balance.

[0006]

However, when the lead filling groove 1a formed on the outer surface of the grip 1 is made deeper or wider, the strength of the grip 1 is reduced, so that the groove 1a is made shallower. And it has to be narrow. In order to balance with the top side, it is most preferable to arrange lead intensively at the grip end E. However, since only the shallow and narrow groove 1a can be formed as described above, the axially elongated groove 1a is formed in the grip portion. And the groove 1a is filled with lead. In this case, the position of the center of gravity of the lead 2 is separated from the grip end E, and therefore, in order to increase the weight on the grip side, the amount of lead must be increased.

[0007] When the amount of lead is increased as described above, the amount of lead is increased despite the weight reduction of the low frame of the molded product. Therefore, the product weight of the racket does not reflect the weight reduction of the low frame. However, there is a problem that the weight of the product cannot be reduced.

Further, lead is fixed in the groove of the grip by hitting it with nails or the like, but if a gap is formed between the inner surface of the groove and lead, the lead will rattle, causing abnormal noise and unpleasant vibration during play. There was also a problem to do.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made to reduce the weight of a low frame, increase the amount of fiber reinforcing material in the face portion, and increase the weight distribution to the face portion to reduce the top heavy. It is an object of the present invention to provide a racket frame in which weight balance is achieved without increasing the amount of lead attached to the grip side so that the reduced weight of the low frame can be reflected as the reduced weight of the racket product.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention firstly provides a racket frame for a fiber reinforced resin product, in which a part of lead arranged on a grip for weight balance is reduced. The lead is molded integrally with the frame and the end of the lead molded with the resin is positioned at the grip end, while the remaining lead is arranged on the outer surface of the grip portion of the low frame, and the lead integrally molded is lead. 30 of total amount
We offer racket frames that range from 70% to 70%. It is preferable that the tip of the integrally molded lead is located at least within 3 mm from the grip end. The present invention is, secondly, a racket frame of a fiber reinforced resin product, in which a part of lead to be disposed on a grip for weight balance is integrally molded with a low frame, and an end of the lead molded with resin is formed. The rest of the lead is placed on the outer surface of the grip of the low frame while being positioned at the grip end, and the lead is 0.89 g / mm to 1.2 g / mm.
And a racket frame characterized by using lead having a high linear density.

[0011] As described above, when the lead to be disposed on the grip is integrally molded with the low frame, the lead is preliminarily fiberized before the resin is injected and molded in a state where the fiber reinforcing material is disposed in the cavity of the mold. In this case, the lead is arranged in the mold together with the reinforcing material. In this case, the lead can be concentrated near the grip end by bending the fiber reinforcing material. By arranging lead at the grip end in this way, weight balance can be achieved while reducing the amount of lead, and the weight of the product can be reduced by reducing the amount of lead.

Further, when lead is molded with a resin, it is possible to prevent the rattling which is likely to occur when retrofitting a conventional molded product with lead, to securely fix the lead, and to eliminate abnormal noise during play. it can.

[0013] The lead to be integrally molded is set to 30% to 70% of the total amount of lead attached to the racket frame. If it is less than 30%, the effect of intensively arranging it at the grip end is small, and if it exceeds 70%. This is because it is difficult to finely adjust the balance, and it is structurally difficult to arrange lead more than 70% at the grip end.
The lead to be integrally molded is preferably 40% to 60%, but the whole amount of lead may be integrally molded. Usually, the total amount of lead is 40 g to 60 g.
% To 60%, the range is approximately 16 g to 36 g.

As described above, it is preferable that the tip of lead be located at the grip end. That is, the lead to be integrally molded is molded longer than the part to be a product, and when cutting as a product, if lead is cut at the same time as the fiber reinforced resin,
Lead can be located at the grip end.

The above racket frame is suitably applied to a top heavy racket frame in which the weight distribution of the face portion is increased by increasing the fiber reinforcement and / or the weight of the face portion surrounding the striking surface. And, specifically, the fiber reinforced material has a long cylindrical shape, and the fiber reinforced material is overlapped on the shaft portion from the face portion via the throat portion and extended to the grip end, and the position of the shaft portion is set. so,
Preferably, the lead is interposed between the fiber reinforcements on both sides, and the fiber reinforcement and the lead are molded with a resin.

As described above, in order to mold lead with a resin, it is preferable that lead used in a mold placed in advance is subjected to knurling so that an anchor effect can be obtained, and the surface is degreased. In addition, it is preferable to improve the adhesiveness to the low frame. Furthermore, if holes and irregularities are provided in the lead and the resin enters into the holes, the adhesion to the resin may be further enhanced.

The lead previously placed in the mold is placed upright on a side of the mold at a position deviating from a part to be a product, and the position of the lead is fixed with the positioning pin. It is preferable to dispose a fixed amount of lead at a fixed position to prevent the movement of lead when filling the resin.

The lead for weight balance used conventionally is a lead having a linear density of 0.4 g / mm to 0.6 g / mm, but in the present invention, 0.89 g / mm to 1.2 g / mm.
1mm from the grip end using lead with high linear density
It is preferably used for any part within the range of 00 mm.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 3, a low frame 10 of a tennis racket frame according to the present invention is made of fiber reinforced resin (FRP). Are arranged integrally. The amount of the lead 12 is 30% to 70% of the total weight of the lead attached to the tennis racket frame, and the remaining lead 13 (shown in FIG. 3) is formed in a concave groove 11a and a groove formed on the outer surface of the grip portion 11. Stepped cutouts 11 on both sides
b and 11b are disposed afterward on the respective end portions E side. That is, the leads 12 and 13 have their respective grip-side ends aligned with the grip end E, and lead is concentrated on the grip end E side.

The method of manufacturing the low frame 10 is shown in FIG.
As shown in the figure, a fiber molded body 16 obtained by laying up a fiber reinforcing material into a long and small-diameter cylindrical shape is converted into a cavity 1 of a mold 15.
5a is arranged in a continuous state in advance. In other words, the face portion 15a-1 in the cavity 15a in the shape of a tennis racket frame is superimposed on the shaft portion 15a-3 via the throat portion 15a-2 and extends from the grip end 15a-4. The extended tip 15a-4 is formed to be longer than the grip end 15a-5 of the racket frame to be a product, so that the tip of the fiber molded body 16 also protrudes from a position to be a product.

Next, the lead 12 having an elongated shape is disposed at the grip portion with the lead 12 interposed between the fiber moldings 16 to be superposed. At that time, the tip of the cavity 1 from the position inside the grip end 15a-5 of the product part
5a-4 are arranged. As shown in FIG. 4B, the lead 12 protrudes into the cavity, and the positioning pin 1 protrudes into the cavity.
The position is fixed at 8.

As described above, after the fiber molded body 16 and the lead 12 are disposed in the cavity 15a, the mold 15 is closed, resin is injected, and the fiber molded body 16 and the lead 12 are molded. Molding. At that time, the cavity of the mold 15 has a structure in which an elongated concave groove is formed in the center of the upper surface in the grip portion, and lower notches 11b, 11b are formed on both sides of the groove at the grip end side. .

After the resin has solidified in the cavity, the mold is opened and the molded product is taken out. On the grip side of the molded product, FIG.
As shown in (C), the fiber molded body 16 and the lead 12 are cut along the line Z to the grip end E which is a product part of the low frame.

In the above steps, the low frame of the tennis racket frame shown in FIGS. 1 and 2 is formed. As shown in FIG. 3, a required amount of lead 13 is retrofitted to this low frame on each end E side of the groove 11a on the outer surface of the grip portion 11 and the stepped notches 11b, 11b on both sides of the groove. .

Examples 1 to 4 according to the present invention and comparative examples for comparison with these examples were prepared as described below.

In Example 1, a blade made of carbon fiber manufactured by Toho Rayon Co., Ltd., 12K32 □ 24 degrees (fibers are set to 24 degrees with respect to the axis), 3K96 □ 24
In a state where 3K48 □ 45 ° was laminated, the fiber was wound around a φ17 mandrel to form a long cylindrical fiber molded body (layup) 16. The weight of the fiber molded body 16 is 98
g. The fiber molded body 16 was placed in the cavity of the mold, and 30 g of lead 12 was arranged between the fiber molded bodies 16 on the grip end side. The surface of the lead 12 was degreased and knurled, and a hole of φ1.5 mm was made.

As described above, after the fiber molded body 16 and the lead 12 having a linear density of 0.98 g / mm are placed in advance, the mold is closed, the temperature is raised to 150 ° C., and then the material is melted at 90 ° C. UX Nylon rim nylon manufactured by Incorporated was injected into the cavity as a matrix resin. Specifically, rim nylon monomer liquids A and B were mixed at a ratio of 1: 1 and injected. The injection pressure was 3 kg / cm ² .

After the resin was solidified, the mold was opened, the molded product was taken out, and cut along the line Z as shown in FIG. 4C to form a low frame. In the low frame 10, the thickness of the frame is 21 mm and the width is 13 m
m, and the total length L of the low frame was 680 mm. The lead 12 cuts a part, so the low frame 10
The amount of lead 12 integrally formed with the resin was 25 g. As shown in FIG. 3, 17 g of lead was attached to the grip portion 11 to the low frame 10. Also, low frame 1
A tennis racket frame (product) was completed by retrofitting a bumper, a grommet, and the like to 0.

In Example 2, a prepreg impregnated with an epoxy resin was laminated to form a fiber molded body 16. The weight of the fiber molded body 16 was 95 g. This fiber molding 1
6 was placed in the cavity of the mold in the same manner as in Example 1, and 25 g of lead having a linear density of 0.96 g / mm was placed between the stacked fiber compacts 16 at the grip portion. The mold was heated to solidify the resin, and then the mold was opened and the molded product was taken out. After that, cutting was performed along the line Z to create a low frame. The weight of the lead 12 integrally formed with the low frame was 20 g, and the lead added later was 18 g. The thickness, width, and total length L of the low frame of the second embodiment were the same as those of the first embodiment.

Example 3 is the same as Example 2, except that the lead set in the mold is 23 g at a linear density of 0.88 g / mm, and the lead integrally molded with the cut low frame is 18 g. The amount of lead added is 25 g.

Example 4 is the same as Example 1, except that the lead set in the mold has a linear density of 1.03 g / mm.
The total length L of the low frame was 717 mm.

In Comparative Example 1, 49 g of lead having a linear density of 0.62 g / mm was attached to the grip side by post-installation without integrally forming lead in Example 1.

In Comparative Example 2, 47 g of lead having a linear density of 0.40 g / mm was attached to the grip side by post-installation without integrally forming lead in Example 2.

Examples 1 to 4 and Comparative Example 1
And the balance length L from the grip end to the position of the balance fulcrum P at the time of a low frame between
The weight of the tennis racket frame product after the lead, bumper, grommet and grommet material were attached, and the above-mentioned balance length L were measured. The results are shown in Table 1 below.

[0035]

[Table 1]

As shown in Table 1, in the low frame stage, in Example 1, the amount of lead to be integrally molded was 59% of the total amount of lead, the frame weight was 214 g, and the balance length L was 34.
3 mm. On the other hand, in Comparative Example 1 which was the same as Example 1 but did not integrally mold lead, the frame weight was 1
Although it was lightweight at 89 g, the balance length L was 390 mm, which is naturally 47 mm higher than that of Example 1 on the top side. On the other hand, the weight of the product after attaching the retrofitted lead and other retrofitting members was 312 g in Example 1.
In this case, the balance length was at a position of 299 mm, but in Comparative Example 1, the weight was 319 g, and the low frame weight was in Example 1.
The product weight was 7 g heavier, and nevertheless the balance length L was 30
At 5 mm, it was top heavy compared to Example 1.
Note that the balance length L is a boundary that does not become top heavy up to 300 mm.

Further, comparing Example 2 with Comparative Example 2,
The amount of lead to be integrally formed was 52% of the total amount of lead. The low frame weight of Example 2 was 208 g, the weight of Comparative Example 2 was 188 g, and the weight of Example 2 was 10 g larger than that of Comparative Example 2. 2 is 310 g, Comparative Example 2 is 318 g, and Comparative Example 2 is heavier. In addition, the balance length L of the product in Example 2 was 298 mm, whereas that of Comparative Example 2 was 307 mm, which was the top heavy regardless of the increase in weight.

Further, the third embodiment is the same as the second embodiment, except that the lead to be integrally molded is 18 g and the lead to be additionally molded is 25 g, and the lead to be additionally molded is increased to 42% of the total amount of lead. %. Therefore, in the low frame, the third embodiment is 2 g lighter than the second embodiment, but the product weight is 3 g heavier than the second embodiment because the amount of lead added after the third embodiment is large. However, the balance length L of Example 3 was 300 mm and was not a top heavy.

In Example 4, although the frame length was 717 mm, which was 37 mm longer than that of Example 2, the product weight was 316 g, and the balance length L was 299 mm, and did not become top heavy.

[0040]

As is apparent from the above description, according to the present invention, a part of the lead to be attached to the grip for weight balance is preliminarily arranged in a mold together with a fiber reinforcing material, and integrally molded by a resin mold. As a result, lead can be concentrated on the grip end. Therefore, the weight balance can be achieved without increasing the amount of lead. Therefore, in the tennis racket frame in which the low frame is lightened to be the top heavy, the moment of inertia equivalent to the conventional level can be obtained while reducing the product weight without increasing the lead weight.

When lead is integrally formed with the frame, the lead is completely fixed to the frame and does not rattle during play.
Generation of unusual noise and unpleasant vibration due to rattling can be eliminated.

[Brief description of the drawings]

FIG. 1 is a plan view showing a low frame of a tennis racket frame according to an embodiment of the present invention.

2A and 2B show a main part of FIG. 1, wherein FIG. 2A is a perspective view and FIG. 2B is a sectional view taken along the line BB of FIG.

FIG. 3 is a sectional view showing that a part of lead is retrofitted.

4 (A) and 4 (B) show steps of manufacturing a tennis racket frame of the present invention, and FIG. 4 (C) is a schematic view showing a lead arrangement position.

FIG. 5 shows a conventional tennis racket frame,
(A) is a plan view and (B) is a front view.

FIG. 6 is a plan view of a conventional tennis racket frame on which lead is arranged, and FIG. 6B is a cross-sectional view taken along line CC of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Low frame of tennis racket frame 11 Grip 12 Lead to be integrally molded 13 Lead to be retrofitted 14 Fiber molding 15 Mold

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A63B 49/08 A63B 49/10

Claims (4)

(57) [Claims] 1. A racket frame of a fiber-reinforced resin product, wherein a part of lead to be placed on a grip for weight balance is integrally formed with a low frame, and an end of the lead molded with resin is used as a grip end. A racket frame wherein the remaining lead is disposed on the outer surface of the grip portion of the low frame, and the lead to be integrally formed is 30% to 70% of the total amount of lead. 2. A racket frame of a fiber-reinforced resin product, wherein a part of lead to be disposed on a grip for weight balance is integrally formed with a low frame, and an end of the lead molded with resin is a grip end. While the rest of the lead is disposed on the outer surface of the grip portion of the low frame, and the lead is a lead having a high linear density of 0.89 g / mm to 1.2 g / mm. And racket frame. 3. The low frame according to claim 1, wherein the weight distribution of the face portion is increased by increasing the fiber reinforcing material and / or increasing the weight of the face portion surrounding the striking surface, and the fiber reinforcing material is elongated. In a cylindrical shape, the fiber reinforced resin material is overlapped on the shaft portion from the face portion through the throat portion and extended to the grip end, and at the position of the shaft portion, between the fiber reinforced materials on both sides for weight balance. The racket frame according to claim 1 or 2, wherein the fiber reinforced material and the lead are molded with a resin with the lead interposed therebetween. 4. An elongated concave shape at the center of the upper surface of the grip.
A single groove is formed, a lower notch is formed on both sides of the groove at the grip end, and lead arranged on the outer surface of the grip is retrofitted to the groove and the notch. Item 4. The racket frame according to any one of items 3.