JP3421324B2 - Golf club - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf club having an improved shaft.

[0002]

2. Description of the Related Art As is well known, a golf club has a club head connected to a shaft tip and a grip provided on a shaft base. As the shaft, a fiber reinforced plastic shaft or a metal shaft using carbon fiber, aramid fiber, glass fiber, or boron fiber is known.

By the way, when hitting a ball in these clubs, a strong stress is applied to the vicinity of the neck where the shaft and the club head are connected. Therefore, a reinforcing rod is inserted into the shaft of the neck portion for reinforcement. It is also known (Japanese Patent Laid-Open No. 6-233843).
However, because the material of the shaft and the material of the reinforcing rod are different,
The durability when stressed is different. For example, a shaft made of FRP has its own problem that the strength in the compression direction is smaller than the tensile strength in the fiber direction. Therefore, the present invention is intended to strengthen the shaft tip portion by the sectional structure of the shaft itself.

Further, the impact force applied to the shaft at the time of hitting also acts in the direction of twisting the shaft, and the twisting also causes deflection in the hitting ball direction, but the present invention particularly improves the directionality of the hitting ball. It is a proposal for a new club.

Various proposals have been made to improve the cross-sectional shape of the shaft, but most of them have a non-circular outer shape and cannot be said to be good in appearance, and it is obvious that the manufacturing is troublesome. is there. Further, although the outer shape is the same as the conventional one, a structure in which ribs are provided inside is also proposed (Japanese Utility Model Laid-Open No. 1-84673), but when a resin-impregnated fiber bundle is wound around a cored bar to be manufactured. However, it is complicated to fill the ribs, which is not practical in manufacturing.

Therefore, the present invention proposes a new golf club which is easy to manufacture and has a strong shaft strength even if its outer shape is a circular cross section.

[0007]

The golf club according to the present invention comprises:
In a golf club in which a club head is connected to a shaft tip portion and a grip portion is provided on a shaft base portion, a shaft outer shape has a circular cross section, a predetermined range of the shaft tip portion has a square hollow cross section, and the circular hollow cross section gradually extends from the square hollow cross section. Is characterized in that the base side has a circular hollow cross section, and in particular, one side of the square hollow cross section of the shaft is aligned with the face surface direction of the club head. .

Therefore, the hollow cored bar can be easily manufactured by the well-known filament winding method or sheet winding method, and the cross-sectional area of the neck portion can be increased, so that the strength can be improved correspondingly. In addition, the twist resistance of the shaft is increased, and the directionality is improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described. The golf club shown in the embodiment is basically provided with the club head 1, the shaft 2 and the grip portion 3 as before, and the club head 1 is connected to the tip of the shaft 2 and the grip is attached to the base of the shaft 2. A part 3 is provided.

The present invention is particularly characterized by the sectional shape of the shaft. The shaft shape will be described in a manufacturing procedure. The core metal 4 is a cylindrical body portion 41 which is thinned at a predetermined ratio from the base portion to the tip portion as illustrated in FIG. 2, and the tip portion (about 20 cm) is a diagonal line. Is a regular quadrangular prism portion 42 thinned at the same ratio as the cylindrical body portion 41, and in particular, the sectional shape in which the sectional moment gradually changes between the cylindrical body portion 41 and the regular quadrangular prism portion 42. As That is, the production shaft is shaped so that stress concentration does not occur.

A resin-impregnated fiber bundle is wound around the core metal 4, or a resin-impregnated sheet (pre-freg) is wound around and cured in a curing oven, and then the outer shape is polished. Then, the cored bar 4 is extracted and produced.

Therefore, the produced shaft 2 has an outer shape of a conventional columnar shape, but the hollow cross section 21 at the front portion is square, and the hollow cross section 22 other than the front portion is the same as a normal shaft. It has a circular cross section.

When the shaft 2 is attached to the club head 1, the face surface direction a of the club head 1 and one side b of the square hollow cross section of the shaft 2 are aligned in parallel.

In the above golf club, however, since the cross-sectional area of the tip portion of the shaft 2 which is the neck portion is large, the necessity of strengthening the strength can be dealt with without any problem, and the impact received by the head at the time of hitting the ball. As for the force, the shaft becomes a torsional stress, and becomes a component force in the striking direction and a component force in the left and right deflection. Particularly, in the rectangular hollow section, since the torsional resistance is strong, a club having a small lateral component force and an excellent directionality of a hit ball is provided.

The present invention is not limited to the above-mentioned embodiment, but as shown in FIG.
And a structure in which the entire hollow cross section of the shaft 2a is square, and the range in which the inner hollow cross section is square is
It is possible to set up to an arbitrary position from the club head side to the grip side end.

[0016]

According to the present invention, in a golf club employing a fiber reinforced plastic shaft, the outer shape of the shaft is a circular cross section and the inner hollow cross section is square, and the square hollow cross section is adopted for the shaft tip. The strength of the neck can be strengthened, and the twist resistance is strengthened.
In addition to improving the directionality of the hit ball, its manufacture has the same advantages as the conventional shaft.

[Brief description of drawings]

FIG. 1 is a perspective view of a shaft according to an embodiment (first example) of the present invention.

FIG. 2 is a perspective view of a cored bar used in the manufacturing.

FIG. 3 is a partially cutaway plan view of the golf club.

FIG. 4 is a perspective view of a shaft according to an embodiment (second example) of the present invention.

FIG. 5 is a perspective view of a cored bar used in the manufacturing.

[Explanation of symbols]

1 club head 2,2a shaft 3 grip part 4,4a core metal 41 cylindrical body 42 Square prism

Claims (2)

(57) [Claims] 1. A club head is connected to a tip portion of a shaft,
In a golf club provided with a grip portion on a shaft base, the shaft outer shape has a circular cross section, and a predetermined range of the shaft tip portion has a square hollow cross section, and the square hollow cross section gradually shifts from the square hollow cross section to the circular hollow cross section on the base side. A golf club characterized in that 2. The one side of the square hollow section of the shaft is aligned with the face direction of the club head.
The listed golf club.