JPH04341283A - Shaft for golf club - Google Patents

Abstract

PURPOSE:To stabilize the direction of a ball by adjusting softness by decreasing mass of a step part, a tip part or a partial wall thickness part extending over both of them of a shaft, and attaching a spring material for giving a stress to the opposed direction of torsion generated at the time of hitting a ball on its part. CONSTITUTION:By making a hole 4 spirally in a step part, a tip part or a partial wall thickness part extending from the step part to the tip part of a shaft, and decreasing mass of the wall thickness part, softness is adjusted. In the overall length or a part of this hole 4, a spiral spring body 5 is installed. This spring body 5 is spiraled so that elastic force is applied to the direction opposed to the torsion direction of the shaft at the time of hitting a ball and both ends are fixed to the shaft, and a stress is applied in advance to the shaft in the direction opposed to the torsion direction. In such a way, the shaft becomes an ultratip condition and the head speed increases, the torsion is prevented, and the direction of a ball is stabilized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a composite shaft for golf clubs.

0002

2. Description of the Related Art Recently, composite shafts made of glass fiber, carbon, etc. are available as shafts for golf clubs, and they are widely used because they allow for relatively easy flight distance.

0003

[Problems to be Solved by the Invention] However, this composite shaft has a problem in that the shaft is twisted the moment the head hits the ball, making it difficult to determine the direction of the ball and making it difficult to hit the ball accurately. In addition, as shown in Fig. 4, the shaft consists of a butt part 1 for gripping, a step part 2 following it, and a tip part 3 for attaching the head.The part from the step part 2 to the tip part 3 is flexible, making it extremely easy to use. However, there is a problem in that it is difficult to reduce the thickness of that part and form an ultra-first tone.

0004

[Means for Solving the Problem] Therefore, the present invention adjusts the flexibility by reducing the mass of the step portion, the tip portion, or a part of the thick wall portion from the step portion to the tip portion of the shaft, and at least adjusts the flexibility. It is characterized in that a spring material is attached to the entire length or part of the part, which applies stress in a direction opposite to the twisting direction that occurs when the ball is hit.

[0005]

[Function] According to the above configuration, the shaft has reduced the mass of the thick part from the step part to the tip part and adjusted the flexibility, so it becomes extremely forward-looking and the head speed increases. By applying stress in the direction opposite to the twisting direction that occurs when the ball is hit by placing it in a part of the tip part, the head is less likely to twist at the moment the ball is hit, and the ball's directionality is improved. It will become stable.

[0006]

Embodiments Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of the main part of the first embodiment, and the shaft is composed of the butt part 1, the step part 2 and the tip part 3, as described above. By drilling holes 4 of a desired diameter in a spiral shape at predetermined intervals in the step part 2, the tip part 3, or a part of the thick part from the step part 2 to the tip part 3, the mass of the thick part is reduced. Adjust flexibility. Note that the cross-sectional shape of this hole 4 may be any shape such as circular, elliptical, polygonal, etc. 5 is a spiral spring body attached to the entire length or part of this spiral hole 4, and this spring body 5 is attached to the torsional direction of the shaft when hitting the ball (for right-handed players, the butt part It is spiraled so that the elastic force is applied in the direction opposite to the clockwise direction when viewed from 1.
Both ends of the spring body 5 are fixed to the shaft, and stress is applied to the shaft in advance in a direction opposite to the above-mentioned twisting direction. The cross-sectional shape of the spring body 5 may or may not match the cross-sectional shape of the hole 4.

FIG. 2 is a cross-sectional view of a main part of the second embodiment, and this embodiment has a step part 2, a tip part 3, or a part of the inner peripheral surface from the step part 2 to the tip part 3 at predetermined intervals. A spiral groove 6 of a desired depth and width is provided to reduce the mass of the thick portion and adjust flexibility. A spring body 5 similar to the above is fitted over the entire length or part of this groove 6, and both ends of the spring body 5 are fixed to the shaft to apply stress to the shaft in advance in a direction opposite to the torsional direction of the shaft.

FIG. 3 is a sectional view of a main part of the third embodiment, and this embodiment has a step section 2, a tip section 3, or a part of the inner circumferential surface from the step section 2 to the tip section 3 to a desired depth. The recess 7 was formed to reduce the mass of the thick part and adjust the flexibility. Both ends of a spring body 8 made of twisted band material are fixed to the entire length or part of this recess 7, and stress is applied to the shaft in advance in a direction opposite to the twisting direction. The material of each spring body may be any material such as metal, synthetic resin, or a composite material thereof. Furthermore, the spirals do not necessarily have to be spaced at equal pitches, and may be installed with the pitches changed sequentially. Furthermore, the wire diameter of the spiral does not have to be the same over the entire length; for example, it may be possible to reduce the diameter toward the tip portion.

In each of the above embodiments, the spring body is mounted by drilling a hole or forming a groove or a recess in the shaft, but the same effect can be achieved even if the spring body is integrally embedded and mounted when the shaft is manufactured. Further, in each of the above embodiments, the spring body is attached to the shaft in advance so as to apply stress in the direction opposite to the torsion direction, but it is not necessary to apply stress in the direction opposite to the torsion direction in advance, and the spring body Simply install the shaft in its normal state so that when a force in the torsional direction is applied to the shaft, stress is applied in the direction that opposes it. Further, in each of the above embodiments, the spring body is attached to the step portion 2, the tip portion 3, or a portion from the step portion 2 to the tip portion 3, but it may be installed over the entire length of the shaft. Although the above explanation was made using a composite shaft, the same effect can be obtained even if the head is used with a metal shaft that is difficult to twist.

0010

According to the present invention described in detail above, the mass of the step portion, the tip portion, or a part of the thick portion from the step portion to the tip portion of the shaft is reduced to adjust the flexibility, and at least By attaching a spring material that applies stress in the direction opposite to the twisting direction that occurs when the ball is hit to the entire length or part of the adjustment part, the tip is extremely flexible and the head speed can be increased, resulting in It has the effect of increasing the flight distance of the ball. Further, the stress of the spring material prevents the shaft from twisting when the ball is hit, and has the effect of stabilizing the directionality of the ball.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a first embodiment.

FIG. 2 is a sectional view of a main part of a second embodiment.

FIG. 3 is a sectional view of a main part of a third embodiment.

FIG. 4 is an explanatory diagram of a shaft.

[Explanation of symbols]

1 Bat part 2 Step part 3 Chip part 4 holes 5 Spring body 6 Groove 7 Recessed part

Claims (1)

[Claims] [Claim 1] The flexibility is adjusted by reducing the mass of the step portion, the tip portion, or a part of the thick wall portion from the step portion to the tip portion, and at least the entire length or part of the adjusted portion is provided with a ball. A shaft for a golf club, characterized in that a spring material is attached that applies stress in a direction opposite to the twisting direction that occurs when the golf club is hit.