JPH0258942B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tennis racket that is mainly made of prepreg, which is a material for molding fiber-reinforced plastics, and its purpose is to prevent wrinkles from forming in the prepreg during molding, and to fully maintain the performance of the material. It is an attempt to repel it.

In detail, by dividing the members that make up the frame of a tennis racket into multiple parts in the thickness direction of the inner and outer sides of the frame, we can reduce the elongation and shrinkage of the wrapped prepreg that makes up each member, and reduce wrinkles. This greatly reduces the occurrence of

Japanese Utility Model Publication No. 57-57 describes that fiber-reinforced plastic (FRP) rackets and carbon fiber-reinforced plastic (CFRP) rackets are known and describes a general method for manufacturing FRP rackets. The present invention is aimed at preventing the wrapped prepreg from shrinking and forming wrinkles especially on the inner side, that is, on the side where the radius of curvature of the frame is small, when folded, in a racket made of this type of fiber-reinforced plastic as the main material. The present invention will be described below with reference to an embodiment illustrated in the drawings.

FIG. 1 is a front view of a tennis racket mainly made of general FRP or CFRP. This tennis racket consists of a series of materials including a frame material 1, a grip 2, a shaft part 3, a ginkgo part 4, and a ball-striking part 5. One method is to obtain frame material 1 by holding and bending this and putting it in a mold and hardening it by pressure heating.The other method is to put the frame material wrapped around a tube with prepreg into a mold and pressurize air into the tube and harden it by heating. There are various methods, but in most cases, foamed synthetic resin is used as the core material 6.

The feature of the present invention is that the frame material 1 is divided into a plurality of parts in the inner and outer directions, and the second
As shown in FIGS. 3 and 3, in this embodiment, the frame members are divided into two inner and outer frame members 1a and 1b.
Both frame materials 1a and 1b are made by wrapping prepreg 7, which is a molding material of FRP or CFRP, around core materials 6 and 6 made of foamed synthetic resin, etc., and these frame materials 1a and 1b are polymerized and molded into a mold. The frame material 1 is then hardened by applying pressure and heating in a known manner.

In this embodiment, the frame material 1 has two members 1a and 1b in the inner and outer directions, but the frame material 1 is not limited to this, and the frame members 1a and 1
Various cross-sectional shapes can be selected for b, and the material for the core material is not limited, and there may be cases where no core material is used.

As described above, the present invention comprises a frame material mainly made of materials such as FRP and CFRP and wrapped with prepreg, which is a molding material thereof, in which a plurality of frame materials 1 are arranged in the inner and outer directions. It is divided into frame materials 1a, 1b..., and
These frame materials 1a, 1b... are each made of the prepreg wrapped around each other, and these frame materials are polymerized, put into a mold, pressurized, heated, and hardened, so that the inside and outside directions of the frame materials are Because each thickness can be reduced, it is possible to reduce wrinkles that occur on the inner prepreg (the side with a smaller radius of curvature when folded), and in addition, in the parts where multiple frame materials overlap, the prepreg tends to expand and contract with each other when folded. Therefore, it is difficult for wrinkles to occur due to interference with each other, and therefore, the original performance of the material can be fully obtained, the appearance is good, and the finishing process is simplified. Furthermore, the prepreg is polymerized inside the frame material. This makes it possible to increase the strength, making it possible to obtain an excellent product for this type of tennis racket.

[Brief explanation of the drawing]

The drawings show the method of the present invention. Fig. 1 is a front view of a tennis racket, Fig. 2 is a sectional view showing a state in which a plurality of frame materials are polymerized, and Fig. 3 is a cross-sectional view showing a state in which a plurality of frame materials are polymerized and molded. FIG.

Claims (1)

[Claims] 1. A frame material whose main material is fiber-reinforced plastic (FRP), carbon fiber-reinforced plastic (CFRP), etc., and which is made by wrapping prepreg, which is a molding material for these materials, in a frame material. The material 1 is divided into a plurality of frame materials 1a, 1b, . . . in the inner and outer directions, and each of these frame materials 1a, 1b, . A tennis racket manufacturing method characterized by polymerizing, placing it in a mold, pressurizing it, and heating it to harden it. 2. A tennis racket according to claim 1, in which the frame material 1 is divided into two in the inner and outer directions, each of which is constructed by wrapping a prepreg around a core material made of foamed synthetic resin, and polymerizing the prepreg. Manufacturing method.