JP2515213B2 - Racket frame molding method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a hitting portion of a racket frame for tennis and badminton having an outer shell layer made of FRP.

[0002]

2. Description of the Related Art Conventional fiber reinforced plastics (hereinafter referred to as
In a racket frame 20 made of FRP), a concave groove 17 is formed on the outer peripheral side surface of the hitting portion in order to prevent wear of the gut exposed from the frame.
The gut hole 18 was formed in the hole, and then the gut protector 14 as a separate body was fitted so as to match the concave groove or the gut hole. In order to mold those racket frames 20, it is necessary to mold the upper mold and the lower mold as well as the side mold for forming the concave groove as the mold.

[0003]

In order to mold the above-mentioned conventional FRP racket frame, since the concave groove formed on the outer peripheral side surface is recessed from the frame peripheral surface, the side surface mold for forming the concave groove is used. It is necessary, and the molding die becomes complicated. Therefore, when molding the frame, the reinforcing fiber bites on the mating surface of the mold, the reinforcing fiber becomes wrinkled, the flow of the resin becomes uneven, and it causes voids. Was also the cause of lowering. Further, after the curing and molding, the post-processing such as the repair and painting of the frame is complicated, which is troublesome. In view of the above-mentioned conventional drawbacks, the present invention simplifies a molding die to improve moldability, does not require attachment of a separate gut protector, and can improve the strength of the racket frame. It is intended to provide a method.

[0004]

In order to achieve the above object, the present invention has the following method. That is, when molding a racket frame in which strip-shaped gut protectors are additionally provided on the inner and outer peripheral surfaces of the hitting portion of the racket frame having the core material and the FRP outer shell layer around the core material, The FRP material for forming the outer shell layer is wound and laminated, and at the same time, the gut protector molding material is held in the gut hole drilling position and placed in the mold, and at the same time as molding, the gut protector molding material is placed on the outer shell layer. This is a method of fusing, and after removing from the mold, a gut protective body is ground to form a racket frame.

In order to hold the band-shaped gut protector molding material, in addition to the method of sticking to the FRP material for molding the outer shell layer,
You may hold | maintain by forming a holding layer lighter than the FRP material for outer shell layer formation on the outer side of a gut protector molded material. In order to form the outer shell layer of the racket frame, the prepreg is used for the outer shell layer forming FRP material by the external pressure forming method, or the reinforcing fiber is placed in the forming die and then formed in the forming die. It can be molded by a reaction injection molding method (hereinafter abbreviated as RIM molding method) or a resin transfer molding method (hereinafter abbreviated as RTM molding method) in which a resin material is injected and molded.

[0006]

According to the method of the present invention, when the hitting portion is formed, the outer peripheral surface of the hitting portion is placed in the forming die while holding the gut protector forming material at the position where the gut hole of the ordinary racket is formed. Therefore, since the outer peripheral surface is formed flat, the mechanism of the forming die can be simplified. Further, since the gut protective body is shaved after the racket frame is hardened and removed, the outer shell layer and the gut protective body are integrated, and it is not necessary to fit eyelets formed separately. Further, since the gut protection groove is formed by post-processing, it is not necessary to make it large as in the conventional case, and turbulent flow generated in the gut groove portion at the time of hitting can be reduced.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a racket frame 1 formed by the method of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of the hitting portion 2. The racket frame 1 has a core body 3 and an outer shell layer made of FRP around the core body 3. And
Recessed grooves 7a and 7b are provided around the inner and outer peripheral surfaces of the hitting portion 2, and gut protectors 4a and 4b made of a thermoplastic synthetic resin such as ABS resin are integrally attached to the recessed grooves 7a and 7b. And the gut protectors 4a, 4b are
A gut hole 8 is formed. Then, in order to mold the racket frame 1, as shown in FIGS. 3 to 4, carbon fiber or the like is used as the FRP molding material 10 for forming the outer shell layer 6 on the core material 5 made of expanded synthetic resin of polyethylene terephthalate resin. Of the sleeve.

Then, the concave groove 7 on the inner and outer peripheral surfaces of the hitting portion 2
The gut protective body molding material 9 is attached to the positions where a and 7b are formed, and the weight of the gut protective body molding material 9 is larger than that of the sleeve constituting the FRP molding material 10 as a holding layer 11 for holding the gut protective body molding material 9. Fewer sleeves were coated more. Then, it is fitted into a mold 12 having a desired racket shape while bending, and after pressing, a molding resin material, for example, a polymer of an epoxy-modified polyaminoamide resin is injected into the closed mold, and Then, it was cured by reaction and molded.
Thus, the RIM molding method or the RTM molding method can be used for molding.

After removing the hardened and molded racket frame 1 from the mold, the gut protective groove 5 is formed in the gut protective molding material 9 fused to the outer shell layer 6 to form the gut integrated with the outer shell layer 6. After the protective body 4 was shaved, a gut hole 8 was bored to form a racket frame. The gut protective groove 5 is formed to grind the gut protective body 4 not only on the outer peripheral surface where the gut may be worn, but also on both the inner and outer peripheral surfaces. The material used may be ABS resin, nylon resin, or the like, as long as it is fused with the matrix resin forming the outer shell layer. In the present embodiment, as the holding layer for holding the gut protector molding material 9 in the FRP material for molding the outer shell layer,
Although a material which is lighter in weight than the fiber material constituting the RP material is used, a thermoplastic tube or the like may be used. Further, without providing a holding layer, for example,
It can also be held by providing a mechanism for locking the gut protector molding material in the mold.

[0010]

As described above, according to the method of the present invention,
Since the outer peripheral surface of the frame has a flat shape with no recessed groove at the time of molding, the side surface mold for forming the recessed groove is not required, for example, the mechanism of the mold becomes simple, and the molding pressure is evenly applied to the frame. , It reduces the generation of voids and allows the resin to easily spread to every corner of the mold.
Further, since the gut protector is previously fused to the outer shell layer as the gut protector molding material, the gut protector integrated with the frame can be formed only by forming the gut protection groove in the gut protector molding material. Therefore, the post process can be simplified. or,
If the gut protector is formed on both the inner and outer peripheral surfaces and the gut holes are bored, the gut can be held without the need to fit a separate eyelet, so that the racket frame can be reduced in weight and weight. In addition, since the gut groove is formed later, it is not necessary to use a large gut protective groove as in the conventional case, and it is possible to reduce the occurrence of turbulent flow at the time of striking in the groove portion, so that aerodynamic characteristics are also improved.

[Brief description of drawings]

FIG. 1 is a racket frame formed by the method of the present invention.

FIG. 2 is a sectional view taken along the line AA.

FIG. 3 is an explanatory view of a molded body.

FIG. 4 is an explanatory view showing a molding method.

FIG. 5 is a sectional view of a conventional racket frame.

FIG. 6 is an explanatory view of forming a conventional racket frame.

[Explanation of symbols]

 1 racket frame 2 hitting ball 3 core 4a gut protector 4b gut protector 5 gut protective groove 6 outer shell layer 7a concave groove 7b concave groove 8 gut hole 9 rod 10 FRP molding material 11 holding layer 12 molding die 14 gut Protective body 15 Gut protection groove 16 Side molding die 17 Recessed groove 18 Gut hole 20 Racket frame 22 Mold

Claims (3)

(57) [Claims] 1. A racket frame having a core material and an outer shell layer made of FRP around the core material.
A method for forming a racket frame having a band-shaped gut protector additionally provided, in which an FRP material for forming an outer shell layer is wound and laminated around a core material, and the FRP material is formed on the outer peripheral surface at a position where a gut hole is formed. Hold the gut protector molding material and place it in the mold,
A method for forming a racket frame, characterized in that a gut protective body molding material is fused to the outer shell layer at the same time as molding, and the gut protective body is ground after demolding. 2. A holding layer is provided on the outside of the gut protector molding material, and the gut protector molding material is used as an F shell for molding an outer shell layer.
The racket frame molding method according to claim 1, wherein the racket frame is held by an RP material. 3. The outer shell of the racket frame is RIM
The racket frame molding method according to claim 1 or 2, wherein the racket frame is formed by a molding method or an RTM molding method.