JPS6329669A - Tennis racket - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a tennis racket, which is characterized by a frame having a two-layer structure of fiber-reinforced composite materials such as graphite, Kepler, and carbon and wood. be.

(Prior Art) In place of conventional wooden frame rackets, many frame rackets made of composite materials such as graphite, Kepler, and carbon have recently been developed and are in use.

(Problem to be solved by the invention) This composite material has excellent properties in terms of reducing the weight of the racket and improving repulsion performance, but on the other hand, it has poor performance in attenuating high-frequency distorted waves. I have so many problems that I have to say.

The minute motion generated in the support part of the stringer is often transmitted to the hands, and unpleasant vibrations are often added to the sound of the ball, which significantly impairs the feel of the ball. Attachments have been devised to prevent these problems, but it is essentially impossible to create a perfect one, and it is impossible to solve the problem without changing the characteristics of the material.

If we limit the issue to the issue of good shot feel, everyone agrees that a racket frame made of wood has the best characteristics.

It is clear that wood has the best characteristics not only in tennis rackets, but also in baseball bats and golf club heads, in terms of impact noise and impact on the hands. The problem is that it has low strength and repulsion performance.

Therefore, rackets made by laminating and reinforcing CFRP between layers of wood have been designed and manufactured (for some time), but increasing the strength increases the weight and makes it difficult to operate, so it is difficult to create lightweight rackets that are easy to operate. If you try to make one, you will end up with a problem that it is not strong enough, and the current situation is that no racket has been made that satisfies players.

(Means for Solving the Problems) This invention aims to solve these problems and provide a racket that is excellent in all aspects such as shot feel, rebound performance, and operability. The material composition is made of two types of composite materials such as graphite and Kepler. Composite materials are used in the main structure to increase strength and reduce the weight of the racket. This main structure was used as a formwork and wood was layered, so that the support part of the gutt was entirely made of wood.

The specific structure of the present invention is to provide a frame main structure made of fiber-reinforced composite material, to form an outer circumferential groove along the outer periphery of the frame main structure, and to bury a wood layer in this outer circumferential groove to form a frame. A large diameter hole is provided extending from the inner circumferential surface of the frame main structure to the bottom surface of the outer circumferential groove, and the large diameter hole extends from approximately the center of the opening end on the bottom surface of the outer circumferential groove of the large diameter hole to the outer periphery of the wood layer. A gut support hole with a smaller diameter than the hole is drilled, and a large number of these large diameter holes and gut support holes are bored at intervals along the frame, and the guts are formed on the outer peripheral surface of the wood layer through each of these gut support holes and each large diameter hole. Guts are placed inside the frame in a lattice pattern to support the frame, and these guts penetrate through the inner circumferential walls of each large-diameter hole without contacting them.

(Function) The main frame structure made of the composite material mentioned above has a section modulus that is sufficient to maintain the rigidity of the racket, the volume fraction of the main frame structure and the wood layer is determined based on the weight design, and the main frame structure is made of the above-mentioned composite material. The amount of wood is determined so that it has a thickness and width that can support the wood, while also making use of the elegance of wood in the design.

The guts are inserted into each gut support hole and supported on the outer surface of the wood layer, and at this time, the guts do not touch the inner peripheral wall of each large-diameter hole that follows each gut support hole, so the guts are ultimately supported only by the wood layer. , not in contact with the composite.

Further, the yoke part is made of wood, and the wood may be provided with gutt support holes, or it may have the same structure as the frame part described above, but the guts are supported by wood and have a structure that does not come into contact with the composite material.

Therefore, the clear hitting sound unique to wood is produced, and the wood layer absorbs the vibrations of the gut when hitting the ball. Furthermore, since the guts are supported on the outer circumferential surface of the wood layer through the support holes of the frame, the tension of the guts serves to bring the wood layer into close contact with the outer circumferential groove of the frame main structure. Also, weights are sometimes enclosed within the racket frame to distribute the mass in order to balance the racket, etc., but in the present invention, the weights can be embedded in the wood layer.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

Reference numeral 1 indicates a frame main structure made of a composite material such as graphite or Kepler; 2 indicates an outer circumferential groove having a generally inverted trapezoidal cross section provided along the outer periphery of the frame main structure 1; 3 indicates a frame main structure 1; The outer circumferential groove 2 and the smaller inner circumferential groove are provided along the inner circumference, and the outer circumferential groove 2 and the inner circumferential groove 3 make the cross-sectional shape of the frame main structure 1 flat in the center, Both sides form hollow bulges 1a and la.

Further, as shown in FIG. 1, the inner circumferential groove 3 disappears at a location where one end of both sides of a yoke, which will be described later, is to be locked, forming a locking convex portion 4. Reference numeral 5 denotes a yoke made of wood whose one end on both sides is locked to each of these locking protrusions 4, respectively, and this yoke 5 is bolted to the frame main structure 1 on both sides. Reference numeral 6 denotes a large diameter hole which passes through the frame main structure 1 between the bottom surface of the outer circumferential groove 2 and the bottom surface of the inner circumferential groove 3 in the frame main structure 1 between the locking projections 4.4 on both sides. A large number of large diameter holes 6 are provided at intervals.

Reference numeral 7 denotes a wood layer buried in the outer circumferential groove 2 excluding the grip portion 8 of the frame main structure 1. They are stacked and fixed. A frame 9 is formed by the frame main structure 1 and the wood layer 7. As shown in FIG. 2, reference numeral 10 denotes a gut support hole extending obliquely through the wood layer 7 from approximately the center of the opening end on the bottom surface side of the outer circumferential groove 2 of each of the large diameter holes 6, and reaching the outer periphery of the wood layer 7. Each of the gut support holes 10 has a smaller diameter than the large diameter hole 6, and adjacent gut support holes 10 are inclined in opposite directions. Figure 2 shows a cross section of the grip part 8 of the frame main structure 1, which is fitted on both sides into the inner circumferential oil grooves 3 of the two frame main structures 1.1 and placed between the frame main structures 1.1. A wood portion 11 is provided, and a filler 12 such as wood extending from the wood layer 7 or foamed plastic is provided in each outer circumferential groove 2 of the frame main structure 1.1. The outer periphery of the structure 1.1 is covered with a covering material 13 made of wood or foamed plastic. Further, weights 14 are appropriately inserted into the wood portion 11 and the filler 12.

Guts are stretched inside the frame 9 in a lattice pattern, and the weft threads of the strings are supported on both the left and right sides through the large diameter holes 6 and the string support holes 10 on both sides of the frame 9. That is, as shown in FIG. 6, the string 15 is exposed to the outer peripheral surface of the wood layer 7 through the large diameter hole 6 and the string support hole 10, and extends along this outer surface to the adjacent string support hole 10. Then, it passes through the large diameter hole 6 that follows this and enters the large diameter hole 6 (not shown) on the other side. In addition, the weft threads of the gutt are connected to the gutt support hole 10 and the large diameter hole 6 in the upper part of the frame 9 in FIG. 1, and the gutt support hole (
(not shown) and are supported at the top and bottom.

FIG. 7 shows a sectional view of another embodiment at the same location as FIG. 2 in the above embodiment. That is, in this embodiment, a thin elastic material 16 such as rubber is interposed between the outer groove 2 of the frame main structure 1 and the wood layer 7.

This elastic material 16 further increases the absorption of impact when hitting the ball and the repulsive force when driving the ball.

In addition to the structure of the above-described embodiment, the racket frame shown in Fig. Weights (not shown) are buried in the wood layer 7 at nine locations in the frame, and at points C and d in the figure.
The point and point b, and the point 0 and point d are provided symmetrically.

The weights at points a and b are designed to amplify the deformation of the frame and the stability of the racket surface at the time of impact of the batted ball.
The weight at point d measures the deformation of the frame and amplification of the swing moment upon impact.

These weights deform the racket into a neat spoon shape as shown in FIG. 9 upon impact of the ball, and the reaction of this deformation improves the flight of the ball. Moreover, this deformation gently wraps around the ball, greatly reducing the shock transmitted to the arm at impact. Furthermore, this deformation allows the ball to be firmly held on the racket, allowing the ball to rest on the surface of the racket for better control.

(Effects of the Invention) The present invention has the above configuration, and since the frame main structure is made of composite material, it is possible to achieve sufficient strength and weight reduction. Moreover, since Gatsuto is entirely supported by a wood layer, there is no high-frequency vibration in the frame made of composite materials, and not only that, the vibrations when hitting the ball are absorbed by the wood layer, resulting in the clear hitting sound that is unique to Gatsuto. It can enhance the feel of the ball to the maximum.

In this way, the present invention makes it possible to take advantage of the excellent characteristics of each material, wood and composite material, while also compensating for each other's shortcomings.

In addition, the tension of the gut has the effect of bringing the wood layer into close contact with the outer circumferential groove of the main frame structure, and the wood does not peel off, resulting in good durability. In addition, conventional frames made only of wood use a separate formwork and the wood is placed inside the formwork and bent or laminated, but in this invention, the main structure of the frame made of composite materials itself is used as a formwork. Since the wood is placed inside this formwork, that is, inside the groove on the outer periphery, there is no need to prepare a separate hood frame. Furthermore, since the wood layer is fixed by being inserted into the outer circumferential groove, there are manufacturing advantages such as no misalignment between the layers when the wood layer is formed by stacking a plurality of thin plates.

Furthermore, when placing weights inside the frame to balance the racket, etc., you can embed them within the wood layer.
The embedding work is easy, and there is no big difference in rigidity between the lead weight and the wood, so stability is good. Furthermore, concerns about peeling when embedding weights in a composite material are eliminated.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view of the racket frame of the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, Fig. 3 is a sectional view taken along line B-B in Fig. 1, and Fig. 1, FIG. 5 is a sectional view taken along line D-D in FIG. 1 is a sectional view of another embodiment of the invention, FIG. 1 is a front view of still another embodiment of the invention, and FIG. 9 is a sectional view of another embodiment of the invention.
FIG. 3 is a side view showing the state of the illustrated embodiment at the time of impact. In the figure, 1 is the frame main structure, 2 is the outer groove, 3 is the inner groove, 5 is the yoke, 6 is the large diameter hole, 7 is the wood layer, 9 is the frame, 10 is the gut support hole, and 15 is the It's gutsy.

Claims (1)

[Claims] A frame main structure made of a fiber-reinforced composite material is provided, an outer peripheral groove is bored along the outer periphery of the frame main structure, a main material layer is buried in the outer peripheral groove to form a frame, and the frame main structure is A large diameter hole extending from the inner peripheral surface to the bottom surface of the outer peripheral groove is provided, and a gut support having a smaller diameter than the large diameter hole is provided, extending from approximately the center of the opening end on the bottom side of the outer peripheral groove of the large diameter hole to the outer peripheral surface of the wood layer. A large number of large diameter holes and string support holes are drilled at intervals along the frame, and the string is supported on the outer circumferential surface of the wood layer through each of these string support holes and each large diameter hole, and the string is formed inside the frame. A tennis racket characterized by having guts stretched in a lattice pattern, and the guts passing through the inner peripheral walls of each large diameter hole without contacting them.