JPS58116372A - Production of 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 The present invention relates to a method for manufacturing a racket frame in which a fiber-reinforced thermosetting resin is molded into the racket frame.

Composite racquet frames generally include a shell consisting of a teO layer of woven glass or carbon fibers impregnated with a thermoset resin and a foam core intimately bonded to the shell. The manufacture of such composite structures typically requires internal pressure to force the shell into intimate contact with the inner surface of the casting cavity and to assume the shape of the shell. There are two ways to generate sufficient internal pressure: a direct method (blow molding) and an indirect method (foam molding). In the first method, the sides of the shell are pressed tightly against the inner wall of the casting cavity by means of compressed air. A foamable thermosetting component is then supplied to the hollow central portion, which is then foamed by heating and hardened within the inner wall. This additional manufacturing step results in additional manufacturing costs.

In a second method, multiple layers of resin-impregnated woven fibers are wrapped around a foamable core component and then placed into a casting cavity and molded. When heat is applied, the blowing agent acts on the core component to create the desired cast shape after curing, but it also applies pressure to gel and harden the resin-infiltrated fibers, and heat The temperatures for foaming the cured plastic resin are not equal.

Therefore, the pressure generated is not controllable and the resin from the core penetrates into the shell layer, thereby destroying the reinforcement of the fibers as well as the orientation of the fibers.

In accordance with the present invention, a method for manufacturing a racquet frame includes an elongated casting cavity having a length extending from a handle portion, around a head portion, and back to the handle portion. providing a flexible strip member; introducing a thermoset resin component and reinforcing fibers into the prepared cavity; and bringing the two flexible strip members together to form a structural member. , bending this structural member into the shape of a racket frame in a tool; curing at a temperature; and removing the strip member after curing.

The racket frame thus formed can have an I-shaped cross section, a concave lens shape, and a notch-like section. The fibers used here are
Vertical fibers, glass fibers, boron fibers, Kepler (kev
lar) or other reinforcing materials.

Strip members can be removed from the molded frame by grinding or by using a mold release agent.

It is an object of the present invention to provide a method that can be used to produce a solid fiber-reinforced racquet frame without applying internal pressure during molding to form a mold.

These and other objects, features and advantages of the invention will become more apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings.

As shown in FIGS. 1 and 2, the racket frame 10 according to the present invention is reinforced with various fibers such as carbon fibers, glass fibers, boron fibers, kevlar, etc. The mold used in this invention is a flexible tube member 11 whose length extends from the handle portion to the head. each of these strip members 11 has a hook-in stop 13 over its entire length, and the two casting cavities are connected together. After matching, the shapes were I-shaped (Fig. 2e), concave lens type (Fig. 3), rectangular with a groove on the - side (Fig. 4), and a groove on the - side and rounded on the other side. Structural members shaped like rectangles (Fig. 5) can be formed. These strip members 11 are used instead of rigid molds, which are much more expensive to make. These members are It is made of plastic, wood pulp, bamboo wood, etc. Plastic strips can be made by extrusion or injection molding, while the molded cavities can be obtained by cutting wood or bamboo.

During the process, the tube member 11 is filled with thermosetting resin and fibers 14, and then the two strips 11 are pressed together and bent into the shape of the racket frame, and then placed in a tool for shaping. placed in

In FIG. 3, two strip members 21 provide a racket frame 22 having a concave lens-shaped cross section. As shown in FIG. 4, by means of the two strips 31 and 41, it is possible to obtain a frame with a combined rectangular 42 and U-shaped cross section 32. In FIG. 5, one strip member 51 has a U-shaped groove 52 and the other strip member 61 has a curved groove 62. In FIG. The groove 62 is first provided with 630 layers of fiber-reinforced resin,
It is then filled with a wood layer 64. two strip members 5
1 and 61 are brought together and bent into the shape of a racket frame.

The resin is then cured at a certain temperature. After curing, both parts can be removed using a mold release agent or by grinding.

Although the invention has been described above, it will be apparent that various modifications and changes can be made without departing from the scope of the invention. Therefore, the invention is limited only by what is shown in the accompanying frame.

[Brief explanation of drawings]

FIG. 1 is an fFn diagram of a racket frame according to the present invention. Figure 2a is a perspective view of a flexible strip member according to the invention. Figure 2b is a perspective view of the IJ tube member filled with casting compound. FIG. 2C is a cross-sectional view of two pressed strip members. FIG. 2e is a sectional view of the racket frame of the first embodiment of the present invention. FIG. 3 shows a second embodiment according to the present invention.
It is a sectional view of the racket of an example. FIG. 4 is a sectional view of a racket frame in a third embodiment of the present invention. FIG. 5 is a sectional view of a racket frame in a fourth embodiment of the present invention. Code explanation 10.22... Racket frame 11.21,
31, 41, 51, 61... Strip member 13... Casting retaining part 14... Resin and fiber 6
3...Fibre-reinforced resin patent applicant Yu Ching Sanj'- Agent Patent attorney Takayoshi Hayashi Figure 1 (CJ Figure 2 4't! Figure 3 Figure 4 2 Figure 5

Claims (1)

[Scope of Claims] (11) A flexible material having a length extending from the handle portion, around the head portion and then back to the handle portion, and having an elongated casting cavity extending through the length. providing a strip member; injecting a thermosetting resin component and reinforcing fibers into the casting head; bringing together two flexible strip members to form a structural member; and forming a fixture. A method for manufacturing a racket frame comprising the steps of: bending the frame into the shape of the racket frame within the racket frame, curing it at a certain temperature, and removing the strip member after curing. (2) The method for manufacturing a racket frame according to claim 1, wherein the structural member has an I-shaped cross section. (3) The method for manufacturing a racket frame according to claim 1, wherein the structural member has a concave lens-shaped cross section. (4) The method for manufacturing a racket frame according to claim 1, wherein the structural member # has a notched portion in cross section. (5) The method for manufacturing a racket frame according to claim 1, wherein the fiber is selected from the group consisting of carbon fiber, glass fiber, boron fiber, and kevlar. (6) S) The method for manufacturing a racket frame according to claim 1fA, wherein the removal of the 1771 member is performed by grinding. (The method for manufacturing a racket frame according to claim 1, wherein the removal of the strip member is performed using a mold separation agent.