JPS6080471A - Racket frame - 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 This invention relates to an improvement of a racket frame made of fiber reinforced plastic (hereinafter abbreviated as FRP).

Compared to conventional RP racket frames, when hitting a ball during play, the tip of the racket frame (hereinafter referred to as the frame) does not come into contact with the court surface.
Also, when picking up balls scattered on the court surface during practice, the tip of the frame is often grounded and scooped up, so the tip of the frame repeatedly comes into contact with the court surface, and the tip of the frame 11 The FRP outer shell layer at the end of the frame suffers M loss and its strength decreases, causing the frame to break.Also, the E'R, L-' outer shell layer at the tip of the frame collapses because it cannot withstand the tension of the gut. It had drawbacks such as. Therefore, in order to improve this drawback, Japanese Patent Application Laid-Open No. 58-85633 and Japanese Patent Publication No. 55-38151 have been published.
As shown in Figures 2 and 3, a proposal has been made in the Japanese Patent Publication No. 2, which outlines the idea of arranging a thin metal plate or metal fiber 4 at the tip of the frame 2 to prevent wear and tear and increase strength. It was something. However, in order to arrange the metal thin plate or metal fiber 4 as a strength reinforcement in the PRP outer shell layer 3, it is necessary to improve the adhesion with the matrix resin forming the PRP outer shell layer 3. Therefore, in order to improve the adhesion of metal 4' plates and gold 1/J3 fibers, it is necessary to perform surface treatment or to use adhesives separately.

The drawback was that it took time to knead. In particular, ,F' It
]) Since the rigidity of the F L< P member forming the outer shell layer and the metal differ, stress concentration occurs at the boundary between the two, which may lead to a breakage accident.

Another disadvantage is that the metal surface is exposed due to contact with the court surface during play, resulting in an unsightly appearance. Furthermore, there was a tendency for the entire device, including the tip, to become heavy.

Therefore, the proposal of Japanese Patent Application Laid-Open No. 58-5Q972 shown in FIG.
ing. However, this type of frame also has the following problems. That is, a rubber sheet 5 is placed inside the FRP outer shell layer 3 to protect the front end of the frame.
The rubber sheet 5 has a structure with
The stiffness of the 8 regions of the F RP outer shell layer is higher than that of other FR
Since the P content is lower than that of the outer shell layer, it is subject to creep stress due to the tension of the gut during use, which may cause the tip to deform or the space between the gut holes to cave in. Also, rubber sheet 5 is FDP! Since the structure is interposed inside the A shell layer 3, the FRP layer corresponding to the outermost layer is worn out and the rubber sheet is exposed as in the conventional case. The exposed rubber sheet itself becomes fuzzed due to abrasion, so
Not only did it look unsightly, but because the rigidity was low, the sound when hitting the ball was also low, and the feel was not good.

In view of these conventional drawbacks, the present invention has been developed to achieve good wear resistance by using silicon carbide fibers that have the same rigidity as the outer shell layer that constitutes the frame and are wear resistant. The purpose was to provide a frame with improved strength.

An embodiment of the present invention will be described based on the drawings.

That is, as shown in FIG. 5, in a frame having an outer shell layer 7 made of carbon HL, glass fiber, or any other fiber-reinforced plastic, the fiber-reinforced plastic member that constitutes the tip region including at least the tip of the frame is used. This racket frame is characterized in that the -γ'tll of the racket frame is made of silicon carbide fibers 8.

As described above, in the frame of the present invention, it has been found that the wear resistance is significantly improved by using silicon carbide fibers, unlike the conventional ones, and the rigidity is approximately the same as or equal to that of other fiber-reinforced plastic members. , it has characteristics that exceed those, so it can exhibit the following characteristics that conventional FRP frames do not have.

In other words, by placing fabrics or braided fibers made of silicon carbide fibers as fiber-reinforced plastic near the tip of the frame, wear resistance is approximately six times higher than when carbon fibers are used in the same form. What you can do is
Confirmed experimentally. (According to the Mitsu thick abrasion tester) The stiffness of silicon carbide fiber is 18 in tensile modulus.
000 to 20,000 kg/11'1m, and in the case of carbon fiber, it is 20,000 to 23,000 kg/mm'', so the rigidity of both of them is close to each other. By arranging silicon carbide fiber-reinforced plastic in the area, unlike conventional FRP frames, stress concentration occurs at the boundary area due to the difference in rigidity between the parts, resulting in breakage, or breakage between the gut holes. In addition to eliminating the possibility that the FRP outer shell layer forming the gap will collapse due to the tension of the guts, the rigidity values are approximately similar, so there is a risk of deformation due to creep stress-like forces caused by the tension of the guts. In addition, in the case of the present invention, if Sisocon carbide fiber is used in combination with carbon fiber reinforced plastic, both are black fibers, so even if they are worn out due to contact with the coated surface, they are of the same color and will not be noticeable. Also, in the frame of the present invention, the wear resistance of the silicon carbide fibers in the frame of the present invention is superior to that of conventional ones, so it protects the other reinforced plastic layers that make up the frame. However, the durability of the frame is significantly improved.Furthermore, in the present invention, a reinforced plastic layer made of silicon carbide fibers is formed in the tip region including the tip that may come into contact with the court surface during play. However, since the specific gravity is lower than that of conventional thin metal plates or rubber sheets, there is no risk of the racket becoming top-heavy, and a racket with good swing balance can be supplied.

In addition, thin metal plates, metal fibers, and rubber sheets used in conventional FRP frames cannot be bonded with matrix resin, so a surface treatment process or a separate process of applying an adhesive is required. Silicon carbide fibers can be integrated with the matrix resin that forms the F and RP outer shell layers, so there is no need for surface treatment or separate fabric production with adhesives, which has the effect of streamlining the work process. It is.

In addition, the silicon carbide fiber-reinforced plastic parts of the present invention include woven fabrics, braids, mats, unidirectional rows,
Chopped strands, tape, etc. can be selected and used in any form as appropriate, and they can also be placed on the outer surface of the frame as shown in Figure 6, or on the protruding corners of the outer side of the frame as shown in Figure 7. It can be placed in one part, or it can be used to cover the entire circumference of the frame using woven fabric or braid as shown in FIG. Alternatively, as shown in FIG. 9, it may be used in the outer shell layer of the frame.

In the experimental example, it is most desirable to place it on the outermost layer of the frame outer shell layer, but as shown in Figure 9, a thin FRP layer such as scrim cloth is placed on the silicon carbide fiber layer as the outermost layer. It is also possible to perform surface finishing.

As described above, the present invention improves the wear resistance of frames using foam core materials, hollow frames, etc.
We can supply racket frames that have significantly improved durability by acting as strength members, and have a specific gravity that is comparable to other FR frames.
Since the racket uses only P parts, it is possible to supply a racket frame with good swing balance.

[Brief explanation of drawings]

FIG. 1 is a 51' side view showing the racket. FIG. 2 is a cross-sectional perspective view of a main part of a conventionally known FRP frame. Figures 3 and 4 are cross-sectional views of conventional FRP frames;
FIG. 5 is a structural diagram showing an embodiment of the frame according to the present invention. 6, 7, 8, and 9 are cross-sectional views of frames showing other embodiments of the present invention. 1... Racket, and dispute...F Rp jll frame, 3... FRP outer shell layer, 4... Metal thin plate, 5...
...Rubber sheet, 6...Racket frame, 7...
FRP outer shell layer, 8Φ... silicon carbide fiber, A...
...Frame destination tW area. Figure 2 Figure 3 Figure 7

Claims (1)

[Claims] 1. In a frame having an outer shell made of fiber-reinforced plastic, one sound 1s of the fiber-reinforced plastic member constituting the tip region including the tip of the frame is made of silicon carbide fiber. i
: Characteristic racket frame.