JPS5923224B2 - Manufacturing method of injection racket - Google Patents

Description

Detailed Description of the Invention The present invention utilizes a fiber-reinforced plastic armor core as a strength member and coats the outer shell with a fiber-reinforced thermoplastic synthetic resin, thereby achieving production efficiency that exhibits the mutual effect of FRP and FRTP. The present invention relates to a manufacturing method that provides a highly durable racket.

Conventionally, prepreg made of glass fiber or carbon fiber cloth or braid impregnated with matrix resin such as epoxy resin is wrapped around a foam core material or tube, inserted into a mold, and cured under heat and pressure to produce FRP. Methods of molding rackets are known.

It is also known to manufacture a racket by injecting fiber-reinforced thermoplastic synthetic resin (FRTP) mixed with chopped glass fiber or carbon fiber into a racket-shaped mold. However, these conventional rackets have the following various drawbacks. That is, in the former FRP racket, defects in appearance tend to appear due to non-glue areas in the board and matrix resin on the molding surface that occur during molding, and as a result, post-processes such as finishing painting are extremely time-consuming. In addition, because the racket frame body and yoke member were made separately, and the yoke member was screwed to the frame or bonded with adhesive, the yoke part could crack due to repeated stress during use, and strange sounds could occur when hitting the ball. There were problems such as. The latter method of injecting FRTP to form a racket allows for mass production, but due to the design and manufacturing of the racket, the frame hitting part is solid molded, which results in poor balance between the grip side and the ball hitting part side. Furthermore, in order to increase the strength, it is necessary to increase the thickness of the frame, which has the disadvantage of making the racket heavy and difficult to swing. Therefore, recently, a method has been disclosed in which a core made of foamed synthetic resin is placed in a mold using a large number of small, thin locking pins at a location corresponding to the ball hitting part, and FRTP material is injection molded. However, FRTP
There is a risk that the foam core material may be deformed or the locking pin may come off due to the high temperature and high pressure conditions that occur when filling the material into the mold, and the drawbacks of the conventional method have not been improved.

In view of these conventional drawbacks, the present invention was made with the aim of improving the conventional drawbacks by covering the core material made of FRP material with FRTP material as an outer shell reinforcing layer, and at the same time integrally molding the yoke portion with FRTP material. It is something that

To explain the present invention based on the drawings, as shown in FIGS. 1 to 4, a locking member is provided on the upper and lower surfaces of the FRP core 1 in the front width direction that substantially coincides with the shaft portion from the racket ball hitting portion. A locking pin fitting hole 2 is provided, and a locking pin 3 having a flange on its body that fits into the fitting hole 2 is inserted and fixed.

Next, a set of metal parts is prepared, in which a cutout groove 5a for yoke molding is previously provided at a location corresponding to the racket yoke portion 11, and a locking hole 4 for inserting the locking pin 3 is also provided in the same manner. The above-mentioned FRP core body 1 is placed in the molds 5, 5', 5'5.
By inserting the locking pins 3 protruding from the upper and lower surfaces of the core into the fitting holes 4 provided in the mold,
A gap 6 corresponding to the thickness of the outer shell reinforcing layer is formed between the outer peripheral surface of the core and the inner wall surface of the mold. Next, FR is applied to the void.
By injecting and filling the TP material from the grip side using the nozzle 7, the outer shell reinforcing layer 9 of the racket frame is formed. Next, remove from the mold. Remove the protruding part of the locking pin 3 that protrudes from the racket frame, and insert the cut hole 1.
This method of manufacturing a racket is characterized in that the racket is manufactured by performing finishing work such as perforating holes. Above is the method for manufacturing a racket according to the present invention. This produces the following effects not found in conventional rackets.

In other words, it has a structure in which the core body made of FRP is the strength base and the outer shell is reinforced with FRTP, so it is different from the conventional FRP.
Unlike rackets made of RP alone, there is no longer the need to repair boards or glue holes on the surface before painting, and by changing the colors of the FRTP material, there are many colors available for the racket frame. I can do it.

Furthermore, by designing the locking pin into a round, square, or star shape, various patterns can be created on the racket frame. In addition, in the present invention, when the outer shell of the racket frame is injected and extruded using FRTP, the yoke part is also molded at the same time, so unlike conventional rackets, cracks or adhesive peeling may occur at the screw attachment parts or adhesive parts, or cracks may occur when hitting the ball. It is possible to supply a highly durable racket without causing any strange sounds.

In addition, in the manufacturing method according to the present invention, in order to securely support and arrange the FRP core body in the mold using locking pins, unlike the conventional injection racket, the FRTP
Due to the flow of high temperature and high pressure resin when injecting and filling the material,
The core material is not deformed, the locking pins are not dislodged, and the locking pins do not dislodge or shift, improving yield during manufacturing and greatly increasing production efficiency. In addition, when using the FRP core of the present invention, even if there are defects in appearance such as boards or glue holes during core molding, it can be formed into a relatively lug shape. Since production costs are low,
By the method of manufacturing a racket according to the present invention, it is possible to supply an inexpensive racket with good production efficiency and improved durability.

[Brief explanation of the drawing]

1 and 2 are perspective cross-sectional views of main parts showing a state in which a locking pin is inserted into an FRP core of a racket according to the present invention. FIG. 3 is a sectional view of a main part showing the state in which the FRP core is supported and arranged in a mold by locking pins during manufacture of the same racket. FIG. 4 is a perspective view showing how the racket is assembled into a mold during manufacture. FIG. 5 shows the front view of the finished product of the racket according to the present invention? FIG. 6 is a cross-sectional perspective view of the main parts of a conventional FRP racket. FIG. 7 is a sectional perspective view of the main parts of a completed racket according to the present invention. Figure 8 is Figure 5A-
A cross-sectional view taken along line A. FIG. 9 is a sectional view taken along line B-B in FIG. 5. FIG. 10 is a sectional view taken along line CC in FIG. 5. 1: FRP
Manufactured core body, 2: Fitting chip L3: Locking pin, 4: Mold fitting chip L5: Mold, 5a: Notch groove for yoke molding, 6: Gap, 7 Nozzle for re-injection, 8: FRP racket, 9: FRTP shell reinforcement layer, 10: Gadzu F-ILll:
York, 12: Eyelet.

Claims (1)

[Scope of Claims] 1. A locking pin fitting hole is provided on the upper and lower surfaces of the racket made of fiber-reinforced plastic (hereinafter abbreviated as FRP) in the front width direction that substantially coincides with the shaft portion from the ball hitting portion, and the fitting hole is provided with a locking pin fitting hole. FRP with a locking pin with a flange inserted and fixed in the body that matches the
A core is prepared, and a cutout groove for yoke molding is provided in advance at a location corresponding to the yoke portion of the racket frame, and a fitting hole for inserting and fitting the locking pin is also made in the same manner. The FRP core is inserted into a set of molds provided in the mold, and the locking pins protruding from the upper and lower surfaces of the core are inserted into the fitting holes provided in the mold. By providing this, a gap corresponding to the thickness of the outer shell reinforcing layer is formed between the outer peripheral surface of the center body and the inner wall surface of the mold. Next, fiber-reinforced thermoplastic synthetic resin (hereinafter referred to as FRTP) is added to the void.
By injecting and filling the material from the opening on the grip side, the outer shell reinforcing layer of the racket frame is formed.
Next, the racket frame is taken out from the mold, the locking pins protruding from the frame are removed, and the racket is manufactured by performing finishing operations such as drilling gut holes. . 2. The method for manufacturing an injection racket according to claim 1, wherein the FRP core has a hollow structure. 3. The method for manufacturing an injection racket according to claim 1, wherein the inside of the FRP core is filled with foamed synthetic resin.