JP2995345B2 - 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 a head fixed to a front end of a shaft and a grip fixed to a rear end of the shaft.

[0002]

2. Description of the Related Art Various improvements have been made to golf clubs so that the flight distance of a ball can be increased during golf play.

[0003] From such a viewpoint, the present inventor has conducted various studies on the relationship between the behavior of the golf club during the swing and the flight distance of the ball after hitting the ball. As a result, it was clarified that the gyro effect generated during the swing of the golf club had a significant effect on the flight distance of the ball. The new theory will be explained in detail later, and the conclusion is that the gyro effect generated when the golf club swings causes the golf club head to rotate around the axis of the shaft so that the golf club head twists around the axis of the shaft. As a result, the hitting force of the ball increases, and the flight distance of the ball can be extended.

However, according to the conventional golf club, it is difficult to expect a remarkable gyro effect, and it has been impossible to extend the flight distance of the ball as desired. This is due to the fact that the shaft is largely bent and deformed during swinging of the golf club and its deflection is increased, as will be apparent from the later description.

[0005]

SUMMARY OF THE INVENTION The present invention has been made based on the above-described novel recognition, and an object of the present invention is to suppress the reduction of the gyro effect by suppressing the deflection of the shaft during the swing. Another object of the present invention is to provide a golf club capable of greatly extending the flight distance of a ball.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a golf club as described at the outset, wherein the bending stiffness of a shaft portion to which a grip is fixed is reduced to 1200.
We propose a configuration set to × 10 ⁴ kgmm ² or more.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, and the gyro effect at the time of a swing of a golf club and conventional problems will be more specifically clarified with reference to the drawings.

FIG. 1 is an explanatory view of a situation where a player P swings a golf club 1 and hits a ball as viewed from a side opposite to a flight direction of the ball. FIG. 2 is a direction of an arrow II in FIG. It is the partial view seen from. The golf club 1 has a shaft 2, a head 3 fixed to a tip end thereof, and a grip 4 fixed to a rear end of the shaft 2, and a player P holds the grip 4 and moves from the plane of FIG. Swings the club 1 from the near side and hits the ball 5.

Here, the gyro effect of the golf club will be clarified. The golf club 1 during the swing is rotating with a predetermined angular momentum about the rear end of the grip 4, and its axial vector near the impact is represented as indicated by L in FIG. This angular momentum L is a direction perpendicular to the swing plane of the club 1.

On the other hand, although a centrifugal force acts on the golf club 1 with the center of the player P at the center of the neck, the mass of the shaft 2 is generally smaller than the mass of the head 3.
Ignoring the mass of the shaft 2 for the sake of simplicity,
The centrifugal force F acts on the center of gravity G of the head 3 of the golf club 1. At this time, as is clear from FIG. 1, the line Q connecting the rotation center T and the center of gravity G does not coincide with the axis X of the shaft 2, and they form an angle of θ with each other. Therefore, the centrifugal force F is set to the direction of the axis X of the shaft 2 and
It is decomposed into a direction orthogonal to this, and the latter component is defined as F1. On the other hand, assuming that the shaft 2 of the golf club 1 does not bend and deform, the length along the axis X of the shaft from the portion where the player P grips the grip 4 to the center of gravity G is R.
Then, a torque represented by the product of the length R and the component force F1 acts on the club 1. When this is represented by an axial vector, it is as shown by an arrow N in FIG.

The above-mentioned torque N is obtained by
It acts in the direction of "bowing" in the direction of the component force F1, and acts to change the angular momentum L of the rotating golf club 1. When a torque that changes the angular momentum acts on the rotating object in this way, an angular velocity represented by the axial vector ω in FIG. 1 is generated in a direction perpendicular to the angular momentum L and the torque N. This angular velocity ω is ω = L
× N (cross product). That is, the golf club 1
The shaft 2 has an angular velocity of magnitude ω in the direction indicated by the arrow S in FIG. Therefore, the player P
Without intentionally rotating the shaft 2 about its axis X, the shaft 2 naturally turns (turns) in the direction of arrow S so that it is twisted about its axis X. This is the gyro effect of the golf club 1. As a result, given that the distance from the center of gravity G to the axis X is r, the center of gravity G of the head 3 rotates around the axis X of the shaft 2.
The impact force corresponding to the speed ω is added.

Since the head 3 rotates around the axis X as described above, the head 3 hits the ball 5 with a large impact force corresponding to this speed. Therefore, the greater the gyro effect is obtained, the greater the hitting force of the ball 5 and the longer the flight distance.

The above is the new golf theory revealed by the present inventor. However, as described above, according to the conventional golf club, it is difficult to obtain a large gyro effect, and the flying distance of the ball 5 is too small. I couldn't stretch it. The main cause is that the shaft 2 is largely bent and deformed during the swing, and the deflection at the tip becomes large. This will be specifically clarified with reference to FIG.

As described above, the torque N is generated in the golf club 1 during the swing. Therefore, Club 1
The shaft 2 of FIG. 3 is bent and deformed as shown in an exaggerated manner in FIG. 3, and the tip side of the shaft 2 bends downward. However, since the shaft 2 of the conventional golf club 1 is easily bent and deformed,
The deflection δ at the tip of the club was a very large value.

In the above description of the gyro effect, it is assumed that the shaft 2 does not bend and deform, and the player P
Has the length R from the portion where the grip 4 is gripped to the center of gravity G of the head 3 along the axis X of the shaft 2, but the shaft 2 is greatly bent as in the conventional club 1 shown in FIG. When deformed, the length R needs to be considered as a length R1 along the extension line X1 of the axis of the shaft portion 21 on which the grip 4 is supported. That is, the length R1 when the shaft 2 is greatly bent and deformed is much smaller than the length R when the shaft 2 is not bent and deformed. If the length R becomes R1, the torque N becomes F1 × R1
And the value is smaller than F1 × R. Since the angular velocity ω due to the gyro effect is represented by L × N, when the length R becomes R1, the angular velocity also shows a small value, and the gyro effect is reduced.

As described above, as the shaft 2 undergoes a large bending deformation during the swing of the club 1 and the deflection δ at the tip thereof increases, the angular velocity ω decreases and the ball 5
The impact power of the ball is weakened, and the flight distance is reduced. For this reason, it has been difficult to increase the flight distance of the ball 5 with the conventional golf club 1 in which the deflection δ of the shaft 2 is large. From this fact, it can be understood that in order to enhance the gyro effect and extend the flight distance of the ball, the shaft 2 should be configured so that the shaft 2 is not bent and deformed as much as possible. The present invention has been made from such a viewpoint.

In order to suppress the bending deformation of the shaft 2, when the overall bending stiffness, that is, the longitudinal elastic modulus of the shaft 2 is E and its second moment of area is I, the coefficient represented by EI may be increased. It is club 1
If the bending stiffness EI of the shaft portion 21 (FIG. 1) supporting the grip 4 is increased, the bending deformation at the root portion of the shaft 2 can be suppressed.
Can be effectively suppressed.

Therefore, in the golf club of this embodiment,
The bending stiffness EI of the shaft portion 21 to which the grip 4 is fixed is set to 1200 × 10 ⁴ kgmm ² or more.
With this configuration, the deflection of the tip end of the shaft 2 can be effectively suppressed, and the torque N, and hence the value of ω = L × N, that is, the gyro effect can be enhanced, and the impact force on the ball 5 and therefore the flight distance can be greatly increased. be able to.

If the shaft 2 is greatly twisted and deformed during the swing of the club 1, the gyro effect is also reduced. Therefore, it is also important to set the material and the cross-sectional shape so that the shaft 2 is hardly twisted and deformed. It is. Further, the distance r from the center of gravity G of the head 3 to the axis X of the shaft 2 is set as large as possible to increase the rotation speed rω of the center of gravity G so that the head 3 can rotate around the axis X effectively at the time of hitting the ball. Is desirable.

[0020]

According to the present invention, the gyro effect is enhanced and the flight distance of the ball is increased by a very simple structure in which the bending stiffness of the shaft portion supporting the grip is set to 1200 × 10 ⁴ kgmm ² or more. It can be stretched.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a golf club according to the present invention and a gyro effect thereof.

FIG. 2 is a partial view seen in a direction II in FIG.

FIG. 3 is an explanatory view showing a defect of a conventional golf shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Golf club 2 Shaft 3 Head 4 Grip 21 Shaft part

Claims (1)

(57) [Claims] In a golf club having a head fixed to a tip end of a shaft and a grip fixed to a rear end of the shaft, the bending stiffness of a shaft portion to which the grip is fixed is set to 1200 × 10 ⁴ kgmm ² or more. A golf club characterized by being set.