JPS6362227B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a racket frame made of a carbon fiber-reinforced foamed synthetic resin base made of a thermosetting foamed synthetic resin reinforced with carbon fibers.

Conventionally, this kind of synthetic resin racket frame,
For example, in a racket frame made of fiber-reinforced plastics (hereinafter abbreviated as FRP) using glass fiber or carbon fiber as reinforcement fibers, the first
As illustrated in Figures and Figure 2, the base 1 is made of FRP.
It is known to have a box-shaped cross-sectional structure with an outer shell 2, and a core part filled with a core material 3 made of foam or the like, or made hollow.

However, with such a conventional structure, the rigidity of the base 1 itself and the tension of the gutt a stretched over the ball hitting part of the frame are borne only by the strength of the FRP 2 of the outer shell, so it is not susceptible to external damage such as wear. Because it is weak, the rigidity tends to decrease, and not only is the holding force against the tension of the gut a weak, but also the elastic waves generated in the ball hitting part of the frame due to the impact when hitting the ball can cause damage to the surface.
There were disadvantages such as propagation through the FRP2 without resistance and easy to generate vibrations on the grip side.

Furthermore, conventionally, as illustrated in FIG.
In the case of a racket frame formed in a sandwich structure of FRP 2 and core material 3, since the FRP 2 arranged through the core material 3 in the tension direction of string a is independent and isolated, The tension of the guts a is borne only by the core material 3, and the core material 3 is constantly subjected to shearing force due to the tension of the guts, so not only is it necessary to use a material that can withstand this, but FRP2
is located on the basic surface, it is unavoidable that the elastic waves caused by the impact when hitting the ball propagate toward the grip side.

The purpose of this invention is to eliminate the above-mentioned conventional drawbacks, to achieve a shock absorption effect when hitting a ball, to reduce the overall weight, and to reliably prevent thermal deformation of the base body due to heat absorption under direct sunlight. Our objective is to provide a racket frame with a unique design.

That is, in order to achieve the above object, the present invention comprises a base made of a thermosetting foamed synthetic resin reinforced with carbon fibers, a non-foamable fiber-free synthetic resin layer is formed on the surface of the base, and ,
The fiber-free synthetic resin layer is colored in a color tone different from the color tone of the base body and having a low heat absorption capacity. In this case, the carbon fiber-reinforced thermosetting foamed synthetic resin constituting the base body is , specific gravity 0.3~
It is preferable that the carbon fiber has a foaming ratio of 0.9, and that the carbon fiber has a combined fiber structure of roving along the circumferential direction of the frame and mat.

The present invention will be described below with reference to the embodiments shown in FIGS. 4 and 5.

As shown in FIG. 4, reference numeral 11 in the figure is a solid base body forming a racket frame 10 according to the present invention. The base 11 is made of carbon fiber reinforced foamed synthetic resin (hereinafter referred to as foamed CFRP), which is made of thermosetting foamed synthetic resin as a matrix material and reinforced with carbon fiber.
), and a fiber-free synthetic resin layer (surface decorative layer) 12 is formed on the outer peripheral surface by painting or gel coat molding.

By the way, the foamed CFRP that becomes the base 11 is
The foaming rate of the foamed synthetic resin is set to a specific gravity of 0.3 to 0.9 (preferably 0.6 to 0.7), the volume ratio to the reinforced carbon fiber is set to 30 to 40%, and the fiber composition of the carbon fiber is adjusted in the frame circumferential direction. The roving and pine are combined in a ratio of 1:3 to 1:12.

In the above embodiment, the entire cross section of the base body 11 is made of a solid structure of foamed CFRP, but as shown in FIG. A hollow portion 13 may be formed by partially or continuously hollowing out 50 to 60% of the area, and the hollow portion 13 may be filled with a substance 14 made of a non-rigid material.

Therefore, according to the structure of the racket frame according to the present invention described above, since the base body has a solid cross-sectional structure made of foamed CFRP, the rigidity and strength of the frame are taken care of by the entire base body, so that the frame can be easily hit by a ball. The tensile force for the tension of the strings a stretched on the part can be borne by the entire base, and the carbon fiber fiber structure consisting of a combination of rovings and strings prevents the parts in contact with the strings from collapsing, In addition to increasing the holding power of the gut, unlike the conventional structure, the strength member is not limited to the surface of the base, so the elastic waves generated by the impact when hitting the ball are refracted and scattered by the bubbles contained in the base and interfere with each other. This makes it possible to reduce the propagation of elastic waves to the grip, and even if the base body has a solid structure, it is possible to prevent the weight of the entire frame from increasing due to the bubbles contained therein. In addition, the fiber-free synthetic resin layer formed on the surface of the substrate is colored in a color different from the color of the substrate (black) because the substrate itself containing carbon fibers is black and has a large heat ray absorption capacity. By doing so, it is possible to prevent thermal deformation of the base material due to heat absorption under direct sunlight, and at the same time, it is possible to protect the base material from external damage and improve its aesthetic appearance.
This has extremely excellent practical effects.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional racket frame, Fig. 2 is an enlarged sectional perspective view of the main part taken along the line - Fig. 1, and Fig. 3 is an enlarged sectional view of the main part showing another example of the conventional racket frame. FIG. 4 is an enlarged sectional perspective view of a main part showing one embodiment of a racket frame according to the present invention, and FIG. 5 is an enlarged sectional perspective view of a main part showing another embodiment according to the invention. 2... Outer shell made of FRP, 3... Core material, 10...
... Racket frame, 11 ... Base body, 12 ... Fiber-free synthetic resin layer, 13 ... Hollow part, 14 ...
material.

Claims (1)

[Scope of Claims] 1. Consisting of a base made of a thermosetting foamed synthetic resin reinforced with carbon fiber, a non-foamable fiber-free synthetic resin layer is formed on the surface of the base, and the fiber-free synthetic resin layer is formed on the surface of the base. A racket frame characterized in that the racket frame is colored in a color tone different from the color tone of the base body and having a low heat absorption capacity. 2. The racket frame according to claim 1, wherein the carbon fiber-reinforced thermosetting foamed synthetic resin has an expansion rate such that the specific gravity is 0.3 to 0.9. 3. The racket frame according to claim 1 or 2, characterized in that the carbon fibers have a combined fiber structure of rovings along the circumferential direction of the frame and mats. racket frame.