JPH0793959B2 - Golf club - Google Patents

Description

TECHNICAL FIELD The present invention relates to a golf club having a shaft having flexibility.

[Problems to be Solved by Conventional Techniques and Inventions]

Conventionally, in golf clubs, generally, the shaft has flexural rigidity, which is a bending characteristic, and during the swing, the restoring force of the bending of the shaft is used to increase the head speed. Generally, the flexural rigidity of the shaft gradually decreases from the grip side to the head side of the tip over the entire length of the shaft, and the flexural rigidity continuously changes in the longitudinal direction of the shaft.

And in the golf club configured in this way,
The speed of the head during the swing is obtained by the sum of the head speed generated by the movement of the club itself and the head speed generated by the restoring force of the bending of the shaft.

However, in the above configuration, the head speed generated by the restoring force of the flexure of the shaft is not sufficient, and there is a limit to the increase in the head speed utilizing this flexure of the shaft, and a sufficient head speed cannot always be obtained.

Incidentally, U.S. Pat.No. 4,123,055 discloses a golf club in which a specific step of the shaft is provided with a tapered step portion whose outer diameter changes rapidly, and the shaft is bent at this step portion. In this golf club, the impact force generated in the step portion is transmitted to the grip so that the player can feel the action of the shaft and the head, and the restoring force of the bending of the shaft by the step portion is obtained. Therefore, even if the head speed increases, there is a certain limit, and similarly to the above-described one-step golf club, the increase in the head speed utilizing the bending of the shaft is not sufficient.

In view of the above points, the present invention intends to provide a golf club capable of efficiently utilizing the flexing action of the shaft and giving the maximum acceleration to the head when the ball is hit.

[Means for Solving the Problems]

According to the present invention, there is provided the above object, in a golf club including a head that hits a ball, a grip that a player grips, and a flexible shaft that connects the head and the grip, in a longitudinal direction of the shaft. A plurality of high-rigidity materials are arranged at desired desired positions along the space so that a plurality of the high-rigidity materials are present at intervals, and the bending rigidity is lowered and the position is raised again by each of the intervals. Is solved by a golf club.

[Work]

In the present invention having the above-described configuration, the bending rigidity of the shaft formed by the intervals between the high-rigidity members disposed on the shaft decreases and rises again, which is the bending point of the shaft during the swing. The bending point of occurs on the grip side of the shaft, and in the next downswing process, the bending point gradually moves to the head side, the bending point is near the head just before the impact of hitting the ball, and the shaft becomes a straight line at the time of impact. Become. In the process of this downswing, the weight M from the bending point to the head at the tip of the shaft has a certain speed V,
Since the bending point moves toward the tip side, the weight M gradually decreases, while the speed V thereof gradually increases according to the law of energy conservation. Therefore, at the time of impact, the weight from the bending point to the tip of the club becomes the minimum, and conversely, the speed of the head becomes maximum and a large acceleration is given. This acceleration is added to the speed of the head generated by the movement of the club itself during the swing, and the head speed is significantly increased.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show the first embodiment of the present invention, and the third embodiment
As shown in the figure, the golf club includes a head 1 for hitting a ball, a grip 2 held by a player, and a shaft 3 connecting the head 1 and the grip 2. In addition, the shaft 3 is head 1 from the grip 2 side.
The diameter is gradually reduced toward the side so that the weight per unit length becomes smaller toward the head side. 1 and 2
As shown in the figure, a large number of skeletons 4 made of highly rigid metal such as stainless steel, various fiber reinforced plastics (FRP), ceramics, etc. are provided inside the shaft 3 over its entire length.
Are arranged so as to be connected to each other by the spherical joint portion 5, and constitute the main body portion of the shaft 3. The outer periphery of the shaft 3 is formed by covering the outer periphery of the bone body 4 joined and joined with the tubular outer layer material 6 having a low bending rigidity and made of a material such as soft vinyl chloride, polyethylene, or rubber. Since the bone-shaped members 4 constituting the main part of the shaft 3 are spherically bonded, they can be bent in a direction such as a right angle to the axis of the shaft 3 and the rigidity of the bonded part 5 is extremely low. The skeleton 4 has a hollow structure to reduce the weight of the shaft 3. Further, the shaft 3 is the outer layer material 6
Since the bone-like body 4 is exposed, the bone-like body 4 is prevented from being exposed and the aesthetic appearance is not impaired. In addition to the above materials, the outer layer material 6 may be made of thin steel or FRP material having high flexibility.

The operation of this embodiment configured as described above will be described with reference to FIG. The figure shows the bent state in an exaggerated manner in order to clarify the action of the shaft.

In FIG. 4, (A) shows the start of the downswing of the club, (B) and (C) show the intermediate stage during the downswing, and (D) shows the time when the head hits the ball. ing. The shaft 3 bends with the joint portion 5 of the skeleton 4 as a bending point during the downswing,
First, at the start of the downswing (A), the bending point a occurs on the rear end side of the shaft, that is, on the side closest to the grip 2. According to the progress of the downswing, this bending point occurs on the tip side from the above a at the first intermediate point (B), that is, on the head 1 side b, and the next second point.
At the intermediate point (C), the bending point occurs at the point d closest to the head 1 immediately before the impact of hitting the ball, the shaft 3 becomes a straight line at the time of impact, and the energy due to the bending of the shaft is generated. Is converted into kinetic energy of the head, and the head speed increases.

Considering the kinetic energy during the downswing of this club, at the start of the downswing (A), there is no energy in the stationary state between the end of the grip 2 and the bending point a, but from the bending point a to the head. The bent parts up to 1 have some energy E _A. That is, the weight M _A of the shaft portion from the bending point a to the head 1 has the velocity V _A , and as a result, this portion has the kinetic energy E _A. At each stage (B), (C), and (D) of the downswing, the weight of the shaft portion from the bending point to the head and the head, its velocity, and the kinetic energy are M _B , M _C , M _D , V, respectively.
_{Assuming B} , V _C , V _D , and E _B , E _C , E _D , the kinetic energy at each stage is E _A = E _B = E _{C according to the} law of energy conservation.
= Is the E _D. However, in each stage of the downswing, the bending points of the shaft 3 are a, b, c and d as described above.
The distance from the inflection point to the head gradually decreases, and M _A > M _B > M _C > M _D = the weight of the head 1. On the other hand, with respect to the speed, since the kinetic energy is constant, on the contrary, V _A / V _B <V _C <V _D = the speed of the head 1.
As a result, the head is accelerated to the maximum degree at the time of impact. Then, the acceleration of the head given by the restoring force of the bending of the head is added to the speed of the head generated by the movement of the club itself, and the overall speed of the head is remarkably increased.

FIG. 5 shows a second embodiment of the present invention.

In the present embodiment, a carbon fiber reinforced resin (CFRP) shaft is provided with a large number of locations along the longitudinal direction of the shaft where bending rigidity decreases and increases again. The outer layer of the shaft 3 is a hollow body 7 of carbon fiber reinforced resin, and a large number of tubular bodies 8 are arranged inside the hollow body 7 at intervals 9 in the longitudinal direction of the shaft 3. As the material of the tubular body 8, the same material as in the first embodiment can be used. Since the portion between the tubular bodies is only the thickness of the outer layer 7, there is formed a portion 10 where the bending rigidity is lowered and the tubular body is raised again.

In the present embodiment, by changing the position of the tubular body 8 in the longitudinal direction with respect to the outer layer 7, it is possible to adjust the transmission transition time of the bending point between the grip and the head, and the golf club adapted to the swing time of the player can be obtained. can get.

FIG. 6 shows a third embodiment of the present invention.

In this example, carbon fiber reinforced resin (CR
FP) shaft manufacturing, the glass fiber 11 is wound around the shaft axis at a right angle.
Carbon fiber was wound around the shaft except for the portion 11 and the portion of the glass fiber 11 was set as the portion where the bending rigidity was lowered and the glass fiber was raised again. Also this fiberglass
Reference numeral 11 narrows the gap toward the tip of the shaft 3, that is, toward the head side, and lowers the bending rigidity on the tip side of the shaft.

According to this embodiment, since the bending rigidity on the head side is particularly low, it is possible to obtain a club in which the head is easy to move even with a light force and the head speed is further increased.

FIG. 7 shows a fourth embodiment of the present invention.

In this example, in the production of a fiber reinforced resin (FRP) sheet by the sheet method, the glass fiber is wound in a belt shape at an arbitrary position in the longitudinal direction of the shaft, and the portion between the belt shapes is bent and the rigidity is lowered and the portion is raised again. It is what

The manufacturing process is as follows.

(1) Wrap a glass fiber sheet around the molding mandrel.

(2) A suitable portion is cut out in a ring shape in the longitudinal direction of the shaft to leave a wide belt-shaped glass fiber layer.

(3) The FRP sheet 12 is wound on it, and the portion where the glass fiber is cut off is set as the portion 14 where the bending rigidity is lowered and rises again.

According to this embodiment, the shaft can be easily manufactured.

FIG. 8 shows a fifth embodiment of the present invention.

In this embodiment, in the shaft formed by winding the carbon fiber 13, the low rigidity portion 14 is formed by changing the winding angle of the portion which should be the portion where the bending rigidity decreases and rises again. That is, the carbon fiber at the portion where the bending rigidity decreases and rises again is wound with a large inclination with respect to the axis of the shaft as compared with other portions having large rigidity, and the rigidity of this portion 14 is made particularly low. There is.

With such a configuration, it is possible to form a portion having low rigidity with one type of material at an arbitrary position.

〔The invention's effect〕

Since the present invention has the above-described function, it is possible to artificially set a large number of factors such as the material, length and diameter of the shaft, the relationship between the shaft and the head, etc., at the intended bending point of the shaft. Regardless of the setting, it can be set easily and surely. The bending point of the shaft gradually shifts from the grip side to the head side from the start of the downswing during play to the impact, so that the speed of the head side at the tip of the shaft increases rapidly at the time of impact, and the head accelerates significantly. As a result, a golf club capable of extending the flight distance of the ball can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing the inside of a shaft according to a first embodiment of the present invention, FIG. 2 is an enlarged longitudinal sectional view of an essential part of the same embodiment, FIG. 3 is a general perspective view of the same embodiment, and FIG. An explanatory view showing the process of bending of the shaft during the downswing of the same embodiment, FIG. 5 is a perspective view showing the inside of the shaft of the second embodiment of the present invention, and FIG. 6 is a view of the third embodiment of the present invention. Front view, FIG. 7 is a perspective view showing the inside of the shaft of the fourth embodiment of the present invention,
FIG. 8 is a front view of the fifth embodiment of the present invention. 1 ... Head, 2 ... Grip, 3 ... Shaft, 4 ... Bone-like body, 6 ... Outer layer material, 7 ... Hollow body outer layer, 8 ... Tubular body, 9 ... Spacing, 10,14 ... … Bending stiffness decreases and rises again, 11 …… glass fiber, 12 …… sheet, 13 …… carbon fiber,

Claims (7)

[Claims] 1. A golf club comprising a head that hits a ball, a grip that is gripped by a player, and a flexible shaft that connects the head and the grip, at any desired position along the longitudinal direction of the shaft. 2. A golf club, wherein a plurality of high-rigidity materials are arranged at intervals so that a plurality of the high-rigidity materials are present, and the bending rigidity is lowered by each of the distances, and a portion is raised again. 2. The golf club according to claim 1, wherein the high-rigidity material is a skeleton. 3. The golf club according to claim 1, wherein the high-rigidity material is a tubular body. 4. The golf club according to claim 1, wherein the high-rigidity material is a glass fiber layer. 5. The golf club according to claim 1, wherein the high-rigidity material is made of a fiber reinforced resin, and the portion where the bending rigidity is lowered is made of a glass fiber layer. 6. The golf club according to claim 5, wherein the intervals of the glass fiber layers are sequentially made denser from the grip side to the head side to further reduce the bending rigidity on the head side. 7. The main body of the shaft is formed by winding carbon fiber, and the portion where the bending rigidity is lowered is formed by winding the carbon fiber so as to be inclined with respect to the axis of the shaft more than other portions. The golf club according to claim 1.