JPS6041951B2 - Manufacturing method of FRP racket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a racket made of fiber reinforced plastic (hereinafter abbreviated as FRP).

Conventionally, as a racket made of FRP, the racket frame body has a core material made of foamed synthetic resin, covered with reinforcing members made of braided or woven fabric of glass fiber or carbon fiber, and impregnated with epoxy resin or polyester resin as matrix resin. A method of molding with a mold is known.

Then, the frame portion 2 of the racket frame main body 1
When attaching the yoke part 3 to the lower part, the following method is generally used.

That is, the yoke part 3 is molded from synthetic resin such as nylon,
After molding the racket frame body, how to attach it with screws, etc. When molding the racket frame body, the yoke part 3 molded from synthetic resin such as nylon is adhered to the racket frame body with adhesive, and simultaneously molded integrally with a mold. There is a method,
In addition, a yoke member made of a reinforcing member made of braided or woven fabric made of the same glass fiber or carbon fiber as the racket frame body and impregnated with matrix resin is incorporated into the mold together with the racket frame body and simultaneously integrally molded. Methods for doing so are also already known.

However, these conventional methods have the following drawbacks.

In other words, after molding the racket frame body, a yoke part molded from synthetic resin such as nylon is attached with screws etc.
In manufactured rackets, the screws loosen due to repeated impact stress when hitting the ball, which causes strange sounds when hitting the ball, and when the ball is hit near the yoke, stress concentrates on the screws, which causes the screws to loosen. It had drawbacks such as damage to the synthetic resin.

Furthermore, when molding the racket frame body, a yoke made of synthetic resin such as nylon is bonded to the racket frame body with adhesive and integrally molded at the same time. It is very difficult to bond the yoke member to the reinforcing member that makes up the racket frame body, so the yoke member is treated with a primer. It had drawbacks such as cracks occurring on the surface of the coating film corresponding to the parts, poor adhesion of the joint parts, and the yoke part coming off.

Therefore, a method has been adopted in which the same reinforcing member as the racket frame body is used as the yoke portion and integrally molded with a mold, but this method also has the following drawbacks.

That is, the yoke member is covered with a core material made of foamed synthetic resin using a reinforcing member such as braided or woven fabric made of glass fiber or carbon fiber, and the metal for molding the racket frame body is coated with the core material made of foamed synthetic resin impregnated with matrix resin. Due to the method of incorporating it into the mold, the reinforcing member of the yoke part is pushed out when the mold is clamped and is interposed as a burr on the parting surfaces of the upper and lower molds. This had the disadvantage that the thickness of the side width of the racket frame became thicker, resulting in variations in the product.

In addition, with open throat type FRP rackets, if the area of the throat part is small, drilling holes in the yoke after molding the racket frame is extremely time-consuming and inefficient, and the yoke is not attached to the mold. When assembling components, the matrix resin is still wet, so it is sticky and has poor workability. In view of these conventional drawbacks, the present invention has been made for the purpose of providing an FRP racket that is durable and highly productive, preventing noise changes and cracks.

The embodiment will be explained based on the drawings. As shown in FIGS. 1 and 2, in a frame 2 in which the frame portion 2 and yoke portion 3 of the racket frame main body 1 are made of fiber-reinforced plastic of the same quality, The yoke portion 3 is constructed by covering a core material 4 made of foamed synthetic resin with a reinforcing member 5 such as a braided or woven fabric made of glass fiber or carbon fiber, and impregnated with a matrix resin made of epoxy resin, polyester resin, etc. A yoke member 6 is formed, the yoke member 6 is inserted into a yoke part preforming mold, a cut hole forming pin is inserted to form a cut hole 7, and only the central part 3a of the yoke part is heated and hardened. The racket frame body member 8 is molded into a yoke shape, and the both ends 3b of the yoke part are taken out from the yoke part preforming mold while remaining uncured, and then the racket frame main body member 8 is covered with the reinforcing member 5.
The preformed yoke member 6 is assembled into a mold for forming the racket frame main body so as to be bonded and bonded.
FR is achieved by pressing the mold, heating and hardening, and integrally molding.
This is a method of manufacturing a racket made of P.

As described above, in the present invention, by preforming the yoke member 6 in advance, the cut holes are bored at the same time and the yoke member is preformed into the required shape. Since the reinforcing member does not become interposed as a burr on the parting surface of the mold, the side width of the racket frame after molding becomes constant.
Products as designed can be obtained, and yields are significantly improved. Furthermore, since the cut holes are also drilled, there is no need to drill cut holes in the yoke portion after the molding is completed, which simplifies the process. It is also possible to drill cut holes using a drill or the like after preforming the yoke portion, and then to incorporate it into the mold for forming the racket frame body.

In addition, only the central part 3a of the yoke part is preformed and hardened, and both ends 3b of the yoke part are made of uncured prepreg, so if the same matrix resin as the frame part 2 is used, it will be easier to bond when bonding. Adhesion becomes good.

As another example, if a prepreg sheet is used as a partial reinforcing material by preforming it integrally with the yoke part, the bonding will be even stronger and durable. !
! This can be supplied by the racket. As described above, the FR of the present invention
The method for manufacturing a racket made of P can improve the drawbacks of conventional manufacturing methods, prevents abnormal sounds and cracks, and is useful as a durable manufacturing method with good production efficiency.

[Brief explanation of the drawing]

Figure 1 is a front view showing an FRP racket, Figure 2 is a
FIG. 3 is a perspective view of the main parts of the preformed yoke member and the racket frame body before they are joined together according to the present invention. FIG. 3 is a perspective view of the main parts of the FRP racket according to the present invention. 1...Racket frame body, 2...Frame part, 3...Yoke part, 3a...Yoke center part, 3b...Yoke End part, 4...
... Foamed synthetic resin core material, 5... Reinforcement member, 6... Yoke member, 7... Cut hole, 8...
・・・・・・Components for the racket frame body.

Claims (1)

[Scope of Claims] 1. A racket frame in which the racket frame body and the yoke portion are made of fiber-reinforced plastic of the same quality, wherein the yoke portion is made of glass fiber, carbon fiber, etc. with a core material made of foamed synthetic resin. A reinforcing member such as a braided or woven fabric is coated and impregnated with a matrix resin such as epoxy resin to form a yoke member.The yoke member is inserted into a mold for preforming the yoke part, and the central part of the yoke part is Only the surrounding area is heated and hardened to form a yoke shape, and both ends of the yoke part are removed from the yoke part preforming mold while remaining uncured.Then, the preliminary part is placed in a racket frame main body member covered with a fiber reinforced plastic reinforcing member. A method for manufacturing an FRP racket, characterized in that a yoke member that has been molded is assembled into a mold for molding a racket frame body so as to be bonded and bonded, compressed in the mold, and integrally molded by heating and curing. 2. A method for manufacturing an FRP racket according to claim 1, which comprises punching a string hole by inserting a pin for forming a string hole in a preforming mold during preliminary formation of the yoke portion. . 3. F according to claim 1, characterized in that a gut hole is drilled with a drill or the like after the yoke part is preformed.
A method of manufacturing a racket made of RP.