JPH06210029A - Manufacture of hollow golf shaft made of resin - Google Patents

Abstract

PURPOSE:To close a hollow hole at the tip of a hollow gold shaft made of a resin easily and assuredly by a method wherein a resin material is formed on both outer peripheries of a mandrel and an auxiliary mandrel which is detachably provided at the tip of the mandrel, and the formed hollow resin material which has the auxiliary mandrel at the tip is separated from the mandrel. CONSTITUTION:A composite mandrel 14 is constituted by fitting an auxiliary mandrel 13 in an auxiliary mandrel fitting hole 12 of a mandrel 11. Under this condition, a resin material 15 including a reinforced fiber is wound around the composite mandrel 14 by a sheet winding or filament winding, and then, when the mandrel 11 is pulled from a resin material 15, the auxiliary mandrel 13 remains on the resin material 15 side, and the hole at the tip of the resin material 15 is closed by the auxiliary mandrel 13. Thus, the hollow part at the tip can be closed at the time of forming, a special after-treatment is not required, an additional work accompanying the combining work with a club head becomes unnecessary, and the working efficiency is improved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a resin hollow golf shaft known as, for example, a carbon shaft.

[0002]

2. Description of the Related Art A hollow shaft of this type is one in which reinforcing fibers such as carbon, boron, titanium, and Kevlar are contained in a thermosetting or thermoplastic resin material. In molding, for example, in the case of a thermoplastic resin, a resin containing these reinforcing fibers is wound around a mandrel and then heat-molded. The resin material containing the reinforcing fibers is formed into a sheet shape or a thread shape in advance,
The former is wrapped around the mandrel by sheet winding and the latter by filament winding.

This hollow shaft has no particular problem when used in a conventional head, but has the following problems when used in a recent bore-through type head. The bore-through type is a type of head in which the insertion hole of the shaft penetrates, and therefore the hollow hole of the hollow shaft is exposed when the shaft is inserted. If the hollow hole is exposed, not only the appearance is bad, but also foreign matter may enter the inside, and in the worst case, the shaft balance may be lost. Therefore, conventionally, a filling material is filled into the hollow hole of the hollow shaft after the head is inserted and fixed to the head, but this filling operation is extremely inefficient. Not only that, it is difficult to obtain the integrity of the filling and the hollow shaft, and there is a risk that they may come off during use.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to more easily and surely close the hollow hole at the tip of the hollow golf shaft based on the above awareness of the problems.

[0005]

SUMMARY OF THE INVENTION According to the present invention, when a hollow golf shaft is manufactured, if the tip of the hollow hole is closed, no special closing work is required after molding, and the connection strength between the closing member and the golf shaft is increased. It was made based on the idea. The manufacturing method of the present invention, on the outer periphery of a rod-shaped mandrel, in the method of manufacturing a golf shaft to form a resin hollow golf shaft by molding a resin material containing reinforcing fibers, at the tip of the mandrel, an auxiliary mandrel can be detachably attached. A step of forming; a step of molding a resin material on the outer circumferences of both the auxiliary mandrel and the mandrel; and a step of separating the molded hollow resin material having the auxiliary mandrel at the tip and the mandrel; I am trying.

It is desirable to form irregularities on the outer periphery of the auxiliary mandrel to enhance the integrity with the resin material. The auxiliary mandrel can be composed of metal material, resin material, wood, or bamboo. Of course, as these materials, materials that can withstand the molding temperature are used depending on the molding mode of the resin material. Also, the material of this auxiliary mandrel is
It can be appropriately selected from these depending on the purpose such as weight application, balance improvement, and simple blockage. Furthermore, this auxiliary mandrel can also be used to improve the feel of a golfer. For example, when a hard material is used as the auxiliary mandrel, the feeling upon shot can be made hard. Hollow golf shafts are also typically painted by ironing. At the time of this ironing coating, it is necessary to support the centers of both ends of the shaft, and in order to support the center, it is preferable that the shaft is hollow. In order to meet this demand, the auxiliary mandrel can be made of a material having at least a hollow tip, and the hollow portion can be cut after mounting on the head.

[0007]

The present invention will be described below with reference to the illustrated embodiments.
FIG. 1 shows an example of the shape of a mandrel 11 used in the method for manufacturing a resin hollow golf shaft according to the present invention. This mandrel 11 has a tapered portion 11a having a smaller diameter than the intended tapered shape of the golf shaft, and a straight portion (grip portion) 11b at the rear portion thereof. An auxiliary mandrel is attached to the tip shaft portion of the tapered portion 11a. The hole 12 is formed.

FIG. 2 shows an example of the shape of the auxiliary mandrel 13 mounted in the auxiliary mandrel mounting hole 12. In each case, a small diameter insertion portion 13a to be inserted into the auxiliary mandrel mounting hole 12 is provided at one end of the auxiliary mandrel 13, and the diameter of the exposed portion 13b is smaller than the diameter of the tip small diameter portion of the mandrel 11. . In the same figure (A), the outer peripheral surface of the exposed portion 13b is a smooth surface, and in the same (B), the exposed portion 13b is shown.
The same as the one in which the retaining groove 13c is formed on the outer surface of b.
Shows a knurled portion 13d formed on the outer surface of the exposed portion 13b, and (D) shows the hollow portion 13d at the tip of the exposed portion 13b.
(e) shows the auxiliary mandrel 13 composed of a combination of a solid material 13f and a hollow material 13g, and the auxiliary mandrel 13 has a hollow portion 13e formed at the tip thereof. . Auxiliary mandrel 13
Can have the same diameter as the tip diameter of the tapered portion 11a of the mandrel 11. In addition, the auxiliary mandrel 13
Of course, as shown in FIG. 2 (F), those having the same diameter can also be used. Further, the auxiliary mandrel 13 having the same diameter can be provided with the additional structure shown in FIGS. 2B to 2E.

The retaining projections and depressions can be formed in an appropriate shape in addition to the groove 13c and the knurl 13d shown in FIGS. 2B and 2C, and the outer periphery of the exposed portion 13b in FIGS. 2D and 2E. Also, it is possible to provide appropriate retaining unevenness. This auxiliary mandrel 13 is made of metal material, resin material, wood, bamboo material,
Alternatively, it can be composed of these composite materials, and by their selective use, not only for the purpose of occluding,
As described above, it is possible to simultaneously achieve the purpose of improving strength, imparting weight, improving balance, improving feeling or imparting feeling. Of course, these auxiliary mandrels 13
The material of (1) is selected to withstand the molding temperature when molding the resin material.

In the present invention, for example, in manufacturing a carbon shaft, first, one of the above auxiliary mandrels 13 is mounted in the auxiliary mandrel mounting hole 12 of the mandrel 11, and the composite mandrel 14 is constructed as shown in FIG. 3 (A). To do. In this state, the resin material 15 containing the reinforcing fibers is wound around it by sheet winding or filament winding ((B) of the same figure). Then, after winding the resin material 15 with a predetermined thickness, the entire resin material 15 and the composite mandrel 14 are thermoformed.

By this molding process, the resin material 15 and the auxiliary mandrel 13 are integrated. By forming the retaining groove 13c and the knurl 13d on the surface of the exposed portion 13b of the auxiliary mandrel 13, the integrity of the resin material 15 and the auxiliary mandrel 13 can be further enhanced, and / or the resin material 15 Before winding the exposed part 13b
By applying an adhesive to the outer peripheral surface of the resin material 1
5 and the auxiliary mandrel 13 can be made more integrated.

The resin material 15 (club shaft 16) integrally having the auxiliary mandrel 13 in this manner is then separated from the mandrel 11. That is, when the mandrel 11 is pulled out from the resin material 15, the auxiliary mandrel 13 remains on the resin material 15 side, and the hole at the tip of the resin material 15 is closed by the auxiliary mandrel 13 (FIG. 7C).

This hollow shaft is inserted, for example, into the through bore 20a of the bore-through type club head 20, and the exposed portion from the through bore 20a is the cutting line A- in FIG.
Cut along A. Of course, this cutting is performed in the middle of the length of the auxiliary mandrel 13,
Various conditions are set so that the tip end of the resin material 15 is blocked by the auxiliary mandrel 13 when the club head 20 is not attached to the club head 20. Then, the center hole of the resin material 15 is not visible at the tip of the through bore 20a of the completed golf club 21, and the auxiliary mandrel 13 is integrated with the tip of the resin material 15 at the time of molding. It does not fall off easily.

The auxiliary mandrel 13 shown in FIGS. 2D and 2E.
Is suitable for ironing. 2 (D),
In the case of (E), when the molding is completed, the club shaft 16
A hollow portion 13e of the auxiliary mandrel 13 is always formed at the tip of the. For ironing, as shown in FIG. 4, the hollow portion 13e at the front end of the resin material 15 and the hollow portion 15e at the rear end of the resin material 15 are held by a pair of center holding members 17, and the center of the club shaft 16 is held. The space is supported, and in this state, the peripheral surface is painted by the ironing machine 18.

In the case of this embodiment, the club head 20
It is preferable to determine various conditions so that when the club shaft 16 is inserted into the through bore 20a and the tip thereof is cut, the hollow portion 13e is cut.

[0016]

As described above, according to the method for manufacturing a hollow golf shaft of the present invention, the hollow portion at the tip can be closed during molding, so that no special post-treatment is required.
Since the additional work required for the connection work with the club head is unnecessary, the work efficiency is improved. Also, by selecting the material of the auxiliary mandrel, strength improvement, weight addition, balance improvement,
It is possible to obtain additional effects such as imparting or improving feeling.

[Brief description of drawings]

FIG. 1 is a side view showing an example of a mandrel used in a method for manufacturing a resin hollow golf shaft of the present invention.

FIG. 2 is a side view showing an example of an auxiliary mandrel used by being attached to the mandrel of FIG.

FIG. 3 is a diagram showing an example of steps of the manufacturing method of the present invention.

FIG. 4 is a side view showing a state of ironing coating.

[Explanation of symbols]

 11 Mandrel 12 Auxiliary Mandrel Mounting Hole 13 Auxiliary Mandrel 13a Small Diameter Insertion Part 13b Exposed Part 13c 13d Detachment Concavo-convex 13e Hollow Part 14 Composite Mandrel 15 Resin Material 16 Club Shaft 20 Club Head 20a Through Bore

Claims (5)

[Claims] 1. A method for manufacturing a golf shaft, in which a resin material containing reinforcing fibers is molded on the outer periphery of a rod-shaped mandrel to form a resin hollow golf shaft, wherein an auxiliary mandrel is detachably provided at the tip of the mandrel. A step of molding the resin material on the outer circumferences of both the auxiliary mandrel and the mandrel; and a step of separating the molded hollow resin material having the auxiliary mandrel at the tip from the mandrel. To manufacture a resin hollow golf shaft. 2. The method for manufacturing a resin hollow golf shaft according to claim 1, wherein the auxiliary mandrel has an outer periphery provided with irregularities for enhancing the integrity with the resin material. 3. The method for manufacturing a hollow resin golf shaft according to claim 1, wherein the auxiliary mandrel is made of a metal material, a resin material, wood, or bamboo. 4. The method for manufacturing a resin hollow golf shaft according to claim 1, wherein at least the tip of the auxiliary mandrel is hollow. 5. The auxiliary mandrel according to claim 4,
A method for manufacturing a hollow resin golf shaft, in which a tubular body is attached to one end of a solid material mounted on a mandrel.