JPS58212464A - Racket and production thereof - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] The present invention relates to tennis rackets, badminton rackets, etc., and a method for manufacturing the rackets. To easily design and produce many types of rackets and to provide rackets with stable quality.

Fiber-reinforced Blanutik rackets using a core made of foamed synthetic resin have been provided, and the manufacturing method is as follows:
A core body is formed from a foamed synthetic resin, a prepreg sheet or mat of glass fiber or carbon fiber is wound around the core body, this is impregnated with a synthetic resin, and the semi-cured state is placed in a mold. Heat molding was performed, and after curing, the product was taken out of the mold and the surface finish was completed through a number of steps such as gouging and polishing.

In this manufacturing method, skill is required in the process of first wrapping the 1-replex sheet or mat around the core, and since heat molding is low-temperature pressing, it takes too long to harden, making it inefficient. . In addition, after curing, deburr 9
The post-processing steps, including the steps involved, were time-consuming, and productivity was not necessarily good.

In particular, in the process of wrapping prepreg sheets or mats and impregnating them with synthetic resin, it was difficult to obtain uniform amounts of quality and strength due to uneven penetration of the synthetic resin and the formation of air bubbles. . Furthermore, there are problems such as high cost due to the large number of processing steps, and the difficulty of achieving the desired weight, hardness, elasticity,
There was a drawback that it was difficult to freely design the balance etc.

The present invention has solved this drawback, and embodiments thereof will be described with reference to the drawings.

That is, a core body made of foamed synthetic resin such as polyimide resin, polyamide-imide resin, or phenol resin with good heat resistance is molded, and protrusions facing the left and right inner surfaces of the frame at the target positions of the gut holes of the core body are formed. 2, 2', protrusions 3 on the top, protrusions on the bottom of the grip, and fitting parts O, O', corresponding to the protrusions on the lower mold j having a racket-shaped recess; 7. g are provided respectively, and the respective protrusions of the core are fitted into each other.

That is, the protrusions 2 and 2' of the core body finish fit into the fitting parts B and O' of the lower mold S, the protrusion 3 into the fitting part 7, and the protrusion into the fitting part g. Thus, the central body/is lower J.

It is supported by the protrusions 2.2' and ♂ on the mold S and suspended in the racket-shaped recess, and a gap is formed between the core body and the lower mold 5. This corresponds to the gap.

:,: has four racket-shaped parts forming a cavity 10.
Place the second mold // and inject synthetic resin from the injection port /2 provided at the required part to fill the void.

10, the outer shell/3 is formed, and after hardening, the protrusion of the core body is removed from the mold and exposed; 2. ,,z′,
This is a racket made by removing 3.4t and finishing it, and a method for manufacturing the racket.

Note that thermoplastic resin is suitable as the synthetic resin for forming the outer shell/3, but other synthetic resins may also be used. It is also possible to manufacture a racket with a reinforced plastic shell by mixing carbon fiber, glass fiber, or other fiber chops with synthetic resin.

Furthermore, a protrusion provided on the core body; 2. ,! ', 3.
It is efficient to mold ll simultaneously and integrally when molding the core body. However, they may be formed separately and integrated.

This invention has the following features.

(b) Since a synthetic resin with good heat resistance was used to mold the foamed synthetic resin core, the core was not deformed by the temperature of the synthetic resin being injected, and the designed core The gap formed by the mold and the mold is filled with synthetic resin as designed, resulting in the desired uniform quality.

(b) A void formed in the same mold by changing the size of the core body? , the size of 10 can be changed freely. That is, when the core body / is formed thick, the void formed by the mold 10 becomes narrower, and the thickness of the outer shell /3 becomes thinner. On the other hand, if the core is made thin, there will be voids created by the mold.

10 becomes wider and the outer shell /3 becomes thicker.

Therefore, by changing the design of the size of the core body in the same mold, the thickness of the outer shell /3 can be changed for the whole or part of the racket. In addition to being heavy and providing strength, the outer shell has a wall thickness of 1/3, making it possible to obtain rackets with different weights, hardness, elasticity, balance, etc.

In this way, it becomes easy to design rackets with desired weight, hardness, elasticity, balance, etc., and it becomes extremely easy to produce rackets of different quality and effectiveness.

(c) When the outer shell/3 is formed by creative molding using a thermoplastic synthetic resin, the curing time is shortened and there is no need to heat or cool the mold, so production efficiency is significantly improved.

(d) Because injection molding allows molding to fit the mold,
There is no risk of flaking, and the surface processing process can be labor-saving.3.C (E) Conventional products require a process of wrapping prepreg In the present invention, these steps and techniques are unnecessary, and the cost is reduced by simplifying the steps.

(f) When a fiber-reinforced plastic outer shell is formed by mixing chopped carbon fiber, glass fiber, etc. with a thermoplastic synthetic resin, the strength and durability of the racket increases.

(G) There is almost no possibility of air bubbles being formed in the outer shell 3, and therefore uniform amounts of quality and strength can be obtained.Thus, according to the method of this invention, the manufacturing process can be labor-saving and production can be improved. The characteristics of this product are that it has improved performance and can provide rackets with a wide variety of qualities and effects.

[Brief explanation of the drawing]

Embodiments of the present invention are shown in which Fig. 1 is a perspective view of a completed product, Fig. 2 is a sectional view of the same essential parts, and Fig. 3 is a perspective view of a core.
Fig. 4 is a perspective view of the mold, Fig. S is a sectional view of the main part with the core body placed on the mold, and Fig. 4 is a sectional view of the main part with the synthetic resin injected. /... Core body, 2.2', 3. G... protrusion, S-...
・Lower mold, l, 1.1, 7. g...Mating part, Wa, 1
0...Void portion, //...Upper mold, /2...Inlet, /3...Outer shell. Figure 5

Claims (1)

[Claims] / A core body of foamed synthetic resin with protrusions provided on the inner surface of the frame and the bottom of the grip is housed in a mold, and a synthetic resin mixed with or without arbitrary fibers is injected and then extruded. A racket characterized by forming a shell and finishing by removing the exposed protrusions of the core. 2. Form a core body of foamed synthetic resin with the required number of protrusions on the inner surface of the frame and the bottom of the grip, and provide a fitting part corresponding to the protrusions in the lower mold with a racket-shaped recess to form the core body. Each protrusion of the body is fitted and housed, and the core body is supported by each protrusion in the lower mold and becomes suspended, forming a gap between the core body and the lower mold. . An upper mold having a racket-shaped recess that forms a void corresponding to this void is placed, and a synthetic resin is created and injected from the injection port provided at the required part to fill the void to form an outer shell. A method for producing a racket, which comprises removing the exposed protrusion of the core after curing from the mold and subjecting it to finishing processing. 3 The synthetic resin includes thermoplastic synthetic resin, and
The method for manufacturing a racket according to claim 2, wherein chopped carbon fibers, glass fibers, and other fibers are mixed therein.