JPH02274270A - Manufacture of badminton racket frame - Google Patents

Abstract

PURPOSE:To reduce molding step by simultaneous molding of a frame with a grip by winding a FRP molding base material for forming a grip outer shell on the outer circumference of a pipe core material followed by closing, and swelling and thermally compressing a tube. CONSTITUTION:By use of a forming mold 20 having a desired racket frame shape, a frame molding material 30 in which a FRP molding base material 32 is wound around a tube 31 is laid along the cavity 21 of the lower mold 20b of the forming mold 20. A pipe core material 41 consisting of a foaming synthetic resin and having its top end forming the core part of a grip conically is fitted to the outer circumference on the terminal part side of the shaft corresponding part 30a of the molding material 30, and a FRP molding base material 42 forming a grip outer shell is wound on and laid along the outer circumference of the pipe core material 41, and then the cavity of the upper mold 20a is fitted on the lower mold 20b followed by closing, and compressed air is blown into the tube 31 of the frame molding material 30, whereby the tube 31 is thermally compressed while being swollen.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for manufacturing a badminton racket frame having a hollow frame structure made of fiber reinforced plastic (abbreviated as FRP). It is made by integrally molding.

[Prior Art] Conventionally, in manufacturing this type of badminton racket frame, the frame molding process and the grip molding process to be attached to the shaft end of the frame are performed separately.

In particular, when molding a grip, 1. For example, as shown in FIG. Sleeve b including part of the
A grip core material C made of foamed synthetic resin is foam molded on the outer periphery of the grip core material C, and at the same time as the foam molding is performed on the outer periphery of the grip core material C.
Alternatively, the current situation is to cover the foam by wrapping it with a skin material d such as leather after foam molding.

[Problems to be Solved by the Invention] Therefore, the conventional manufacturing means described above requires separate molding of the frame, adhesion of the shaft a and the sleeve b of the frame,
The molding process is diverse, such as foam molding of grip core material C, and since the sleeve is used as the core forming material in grip molding, it is necessary to bond the shaft and sleeve after frame molding. Not only is it troublesome to assemble, but also there is a problem that a desk space is created between them, which tends to lead to molding defects and deterioration of quality.

[Object of the Invention] This invention was made under the above circumstances, and its object is to provide a badminton game machine that can reduce the molding process by simultaneously molding the frame and the grip. The purpose of the present invention is to provide a manufacturing method for a racket frame for use in the market.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an FRP molding material that forms a frame outer shell around a tube along the inside of a mold having a desired racket frame shape. Adding a frame molding material consisting of a substantially elliptical stringing portion and a shaft equivalent portion around which material is wound;
A pipe core material constituting the core of the grip is inserted, and a green material for FRP molding that forms the outer shell of the grip is wound around the outer periphery of the pipe core material, and after the mold is clamped, the tube is expanded. In this case, it is preferable that the pipe core material is made of foamed synthetic resin, and the wrapping of the raw material for FRP molding around the outer periphery of the pipe core material is carried out by hot pressing. This may be done either after or before the shaft-corresponding portion is inserted into the end portion side.

Further, the end portion of the shaft-corresponding portion of the frame molding material is adapted to be inserted all or part way into the insertion hole of the pipe core material constituting the core of the grip, and in this case, In all or part of the insertion hole of the core material,
A double pipe structure may be formed by inserting a metal pipe in advance.

Furthermore, when assembling each molding material during molding, especially the FR which forms the frame outer shell of the frame molding material.
It is preferable that the raw material for P molding and the raw material for FRP molding that forms the grip outer shell wrapped around the outer periphery of the pipe core material are partially overlapped and hot-press molded.

[Function] That is, in this invention, a frame molding material is added along the inside of a mold having a desired racket frame shape, and as the tube expands, a hollow FRP shell made of FRP is heated and pressed. In molding the frame, a pipe core material constituting the core of the grip is inserted into the outer periphery of the end portion of the shaft-corresponding part of the frame molding material, and a grip outer shell is fitted around the outer periphery of the pipe core material. Since the FRP molding raw material is wound, it is possible to integrally mold the frame and the grip at the same time, thereby reducing the number of molding steps.

Also, at least in part of the insertion hole of the pipe core material.

By inserting a metal pipe in advance to form a double tube structure, weight and balance adjustment can be performed simultaneously with molding.

Furthermore, when assembling each molding material during molding, the FRP molding green material that forms the frame outer shell of the frame molding material and the FRP molding material that forms the grip outer shell that is wrapped around the outer periphery of the pipe core material. By hot-pressing the raw material so that they overlap partially, the shaft and grip after molding form a strong integral structure.

[Embodiments] The present invention will be described in detail below with reference to illustrated embodiments.

As shown in FIG. 1, numeral 1 in the figure is a frame body of a badminton racket molded by a molding process according to the present invention which will be described later. This frame body 1 is composed of a stringing section 2 having an approximately egg-shaped oval shape on which the string G is stretched, and a shaft section 4 that is continuously formed integrally with the stringing section 2 via a neck section 3. As shown in FIGS. 2(a) and 2(b), the stringing part 2 and the shaft part 4 have a hollow structure with a cylindrical cross section, the frame outer shell being made of FRPla.

A grip portion 5 is integrally molded on the end portion 4a side of the shaft portion 4 at the same time as the frame main body 1 by a molding process to be described later.
As shown in FIG. 3, a grip core material 6 as a cushioning material made of foamed synthetic resin such as foamed urethane resin is interposed on the outer periphery of the end portion 4a of the shaft portion 4, and the outer periphery of this grip core material 6. It consists of a grip outer shell 7 made of FRP and a surface material 8 made of leather or the like wrapped around the outer periphery of the FRP grip outer shell 7, and the tip of the grip part 5 is , is formed into a conical shape, and its outer periphery is protected by a top cab 9 as necessary, and an end cap 10 is provided on the rear end surface.
is provided.

That is, in order to manufacture the badminton racket frame described above, as shown in FIG. , a cavity of the lower mold 20b of this mold 2o is provided.

Next, as shown in FIG. 5, a pipe made of foamed synthetic resin and having a conical tip constituting the core of the grip is attached to the outer periphery of the end portion side of the shaft-corresponding portion 30a of the frame molding material 30. FR into which the core material 41 is inserted and a grip outer shell is formed around the outer periphery of the pipe core material 41.
After winding and attaching the raw material 42 for P molding, the lower mold 20b
Place the cavity 22 of the upper mold 20a on top and clamp the mold.
This is carried out by feeding compressed air (indicated by solid arrows) into the tube 31 of the frame molding material 30 to heat and press the tube 31 while expanding it, as shown in FIG.

In this case, the pipe core material 41 forming the grip outer shell
The FRP molding green material 42 may be wrapped around the outer periphery of the frame molding material 30 either after or before the pipe core material 41 is inserted into the end portion side of the shaft-corresponding portion 30a of the frame molding material 30.

Further, the shaft-corresponding portion 3 of the frame molding material 30
The end portion 0a is designed to be completely or partially inserted into the insertion hole 41a of the pipe core material 41. At this time, as shown in another embodiment in FIG. A metal pipe 51 which also serves as a weight and balance adjustment member may be inserted in advance into the entire insertion hole 41a of the material 41, or in a part as in the illustrated example, to form a double pipe structure. good.

Furthermore, when assembling each molding material during molding, in particular, the FRP molding material 32 forming the frame outer shell of the frame molding material 30 and the grip outer shell wrapped around the outer periphery of the pipe core material 41. Raw material 42 for FRP molding to form
If you attach them so that they partially overlap and hot-press mold them,
After molding, the FRP of the shaft outer shell and the grip outer shell are continuously integrated, which is preferable in terms of strength.

In addition, a tube 31 constituting the frame molding material 30
For example, a single tube made of a 50 μm thick plastic film such as nylon or a tube containing a core metal is used, and the form of the reinforcing fibers of the FRP molding green material (prepreg) 32 wound around the tube is as follows. ,cross,
Various types of fibers such as bag weave, unidirectional fiber material, bias cloth, etc. are suitably used as required, and in particular, FRP molding green material with diagonal unidirectional fiber material as reinforcing fibers is used. When applying internal pressure (for example, 4 to 10 kg/
If it is wound in two to three layers with the inclination direction symmetrical, it is effective in improving the torsional rigidity of the badminton racket frame.

In addition, in the above embodiment, the tube 3 after thermoforming
1 may remain in the expanded state within the frame, or may be shrunk and removed after hot-press molding.

In addition, when attaching protective members such as the surface material that protects the outer surface of the grip, the top cap, and the end cap, these protective members are positioned separately in the mold in advance, and attached at the same time as the grip is molded. It is possible to do so. especially.

The top cap 9 can be molded at the same time as the FRP grip outer shell 7, and in this case, it becomes possible to eliminate the use of a separate top cap.

[Effects of the Invention] As is clear from the above description, according to the present invention, along the inside of the mold having the desired racket frame shape,
A frame molding material consisting of a substantially elliptical string-corresponding part and a shaft-corresponding part in which raw FRP molding material forming the frame outer shell is wound around the tube, and this frame molding material A pipe core material constituting the core of the grip is inserted into the outer periphery of the terminal side of the shaft-equivalent portion of the shaft, and a raw material for FRP molding that forms the grip outer shell is wound around the outer periphery of this pipe core material. Since the tube is expanded and hot-pressed after mold clamping, the frame and the grip can be integrally molded at the same time, thereby reducing the number of molding steps.

Further, by previously inserting a metal pipe into at least a portion of the insertion hole of the pipe core material to form a double pipe structure, weight and balance adjustment can be performed simultaneously with molding.

Furthermore, when assembling each molding material during molding, FRP molding green material that forms the frame outer shell of the 5 frame molding material, and FRP molding material that forms the grip outer shell that is wrapped around the outer circumference of the pipe core material. By hot-pressing the green material so as to partially overlap it, the shaft and grip after molding can be formed into a strong integral structure, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is an explanatory view showing an embodiment of a racket frame manufactured by the method of manufacturing a badminton racket frame according to the present invention; FIGS. FIG. 3 is an enlarged cross-sectional view of the grip part, FIGS. 4 to 6 are explanatory diagrams of the simultaneous molding process of the frame and grip, and FIG. 7 is an explanatory diagram showing another grip molding state according to the present invention. FIG. 8 is an enlarged sectional view of a main part of a grip portion of a conventional badminton racket frame. 20 ・ ・ 20a ・ 30 ・ ・ 31 ・ ・ 32 ・ ・ 41 ・ ・ 42 ・ ・ 51 ・ ・ Molding mold, ・Upper mold, 20b...Lower mold. Frame molding material, tube, raw material for FRP molding, pipe core material, 41a...insertion hole. Raw materials for FRP molding, metal pipes.

Claims (1)

[Claims] (1) FR forming a frame shell around the tube along the inside of the mold having the desired racket frame shape
A frame molding material consisting of a substantially elliptical stringing portion and a shaft equivalent portion around which raw material for P molding is wound is attached, and the outer periphery of the end portion side of the shaft equivalent portion of the frame molding material is attached. A pipe core material constituting the core of the grip is inserted into the pipe core material, and a green material for FRP molding that forms the outer shell of the grip is wound around the outer periphery of the pipe core material. After the mold is clamped, the tube is expanded. A method for manufacturing a badminton racket frame, which is characterized by subjecting it to heat and pressure.