JP2001025519A - Shaft for golf club - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft which can improve a carry and is suitable for a low-centroid and large-sized club head by packing an elastic body capable of suppressing the deformation of a hollow shaft with the repulsive power of the shaft when sharp force is exerted to the shaft and easily deforming when gentle force is exerted thereto into the shaft. SOLUTION: The elastic body 4 is packed into the hollow shaft 1 by winding and forming a paralleling sheet, etc., consisting of high-strength and high- elasticity fibers impregnated with a synthetic resin. The elastic body 4 is packed to a range from 30 to 40 cm from the top end 31 of a neck part 3 to the upper part of the shaft 1 and the upper part thereof is fixed by adhesion 5 over the entire periphery of the inside surface of the shaft 1. An elastic body of a high- polymer system of the nature to exhibit the high repulsive force and to suppress the deformation under the exertion of the sharp force and to be liable to be deformed under the exertion of the gentle force, for example, urethane, etc., are used as the elastic body 4. The shaft which can improve the carry and is suitable for the low-centroid and large-sized club head may be obtained by this concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a shaft for a golf club.

[0002]

2. Description of the Related Art Conventionally, a golf club has a shaft,
Using a high-strength high-elastic fiber (for example, carbon fiber) to form a hollow shape to reduce the weight and increase the head speed due to the deformation (bending) of the material at the time of swing, and when the deformed shaft returns to its original position The initial speed and the flight distance of the ball are improved by increasing the generated repulsive force. In addition, the tendency of recent golf clubs is to increase the size of the club head and lower the center of gravity, and to increase the head speed and repulsion by making the shaft longer and softer, further improving the ball's initial speed and flight distance. Is being planned.

[0003]

The factors that increase the flight distance are, in addition to the head speed and repulsion force, the center of gravity of the club head 100 as shown in FIG.
It is known that by hitting the ball 103 above the intersection of a perpendicular line lowered from 01 to the face surface, the ball initial speed is more effectively improved and the flight distance is extended.

This is what is called a vertical gear effect. At the time of impact, when the ball 103 collides with the club head 100 advancing in the direction of the arrow 102 in the direction of the arrow 104, the club head 10
0, a counterclockwise couple 105 is generated.
Deforms the shaft 106 so as to crush it from the arrow 107.

That is, the correlation between the couple 105 of the club head 100 and the deformation of the shaft 106 is determined by the ball 10.
By rotating the club head 3 clockwise, the backspin affecting the flight distance is reduced and the launch angle is increased. Therefore, recently, the club head 100 is enlarged in the vertical direction and at the same time, the center of gravity is lowered. There is also a device to try.

[0006] However, as a result of the lowering of the center of gravity and the increase in the size of the club head 100 as described above, as shown in FIG.
6 was too large, and the energy loss due to the deformation of the shaft 106 was too large, so there was a limit to increasing the initial velocity of the ball.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances. It is an object of the present invention to suppress excessive deformation of a shaft at the time of impact and to generate a strong repulsive force while making the shaft proper at the time of a swing. Accordingly, it is an object of the present invention to improve the initial velocity of the ball, thereby further improving the flight distance, and to provide a golf club shaft which is extremely suitable for using a low center of gravity and a large club head.

[0008]

The present invention employs the following technical means in order to achieve the above object.

The technical means according to the first aspect of the present invention is a resilient material having such a property that when a force is applied suddenly, a strong repulsive force acts on the entire interior of the hollow shaft, and the hollow shaft is not easily deformed. That is, the golf club shaft is formed by filling the body.

According to the first aspect of the present invention, the elastic body filled therein acts on the deformation of the shaft.

That is, since a gentle force is applied to the shaft during the swing, the filled elastic body is easily deformed, and the bending of the shaft during the swing is ensured. Further, at the time of impact, a sudden force is applied to the shaft due to the impact of the ball on the club head, so that a strong repulsive force is generated in the filled elastic body, making it difficult for the filled elastic body to be deformed. The repulsive force acts as a repulsive force of the shaft, and the repulsive force suppresses the deformation of the shaft, thereby reducing energy loss at impact.

The technical means according to the first aspect of the present invention is configured such that the entire shaft is filled with an elastic body. However, the present invention is not limited to this configuration. Good.

For example, as in the technical means of claim 2,
A sharp repulsive force acts on the tip inside the hollow shaft to apply a sudden repulsive force to prevent deformation, and a golf club shaft filled with an elastic material that easily deforms when a gentle force is applied. That was done.

That is, the tip portion of the shaft is the portion where deformation due to couple occurs most at the time of impact, and it is the portion that most affects the flight distance and directionality, so by filling this portion with an elastic body, The same operation as the first aspect is achieved.

[0015] As a specific range of the range of the front end portion, the range of the front end portion to be filled with the elastic body may be changed from the neck end portion or the vicinity of the end portion. It is preferably 30 cm to 40 cm.

In the above, the elastic body alone is used to suppress the excessive deformation of the shaft and to secure the repulsive force. A mandrel is built in along with the lower end of the mandrel fixed to the tip of the shaft, and the mandrel is inserted into the elastic body so as to suppress excessive deformation of the shaft and ensure repulsion. Is also good. According to the technical means of the fourth aspect, a repulsive force from a deformation such that the elastic body is crushed by the mandrel from inside is added to a repulsive force from a deformation accompanying the deformation of the shaft at the time of impact. That is,
Since the repulsive force of the elastic body acts on the shaft and the mandrel, it is possible to more effectively suppress excessive deformation of the shaft and secure a strong repulsive force.

Further, according to the technical means of claim 5,
By fixing the mandrel and the elastic body by bonding, it is possible to more effectively suppress excessive deformation of the shaft and secure a strong repulsive force, as in the technical means of the fourth aspect. The shaft is slightly deformed due to the deformation of the shaft, but the elastic body integrated with the mandrel is deformed at the same time as the mandrel, so that the repulsive force of the elastic body and the shaft without causing time loss are generated. Can be told.

Further, the elastic body may be adhered and fixed to the shaft as in the technical means of claim 6, whereby the repulsive force of the elastic body acts on the torsion of the shaft. This makes it difficult to twist, and is effective in improving the directionality.

The elastic body is not limited to the whole body which is bonded and fixed, and may be a part of which is bonded and fixed. For example, as in the technical means of claim 7, the upper end of the elastic body is fixed to the shaft. In this configuration, it is preferable that the elastic body is filled at the tip of the shaft as in the second and third aspects.

The elastic body according to the present invention includes all elastic bodies which are hardly deformed due to a strong repulsive force when a sudden force is applied, and are easily deformed when a gentle force is applied. Specifically, a polymer-based elastic body is preferable.

More specifically, the following elastic bodies can be mentioned.

For example, polyurethane (foam obtained by mixing a polyisocyanate and a polyol), polyethylene (foam), polystyrene (foam), latex foam, foamed rubber, pounding putty (impregnated with siloxane containing boron atom), and Is a butadiene-acrylonitrile copolymer, chloroprene polymer, ethylene propylene copolymer, acrylic copolymer, styrene-
Butadiene copolymer, isobutylene-isoprene, polybutadiene, natural polyisoprene, synthetic polyisoprene, natural rubber, polyvinyl chloride rubber, polyamide rubber, polyvinyl chloride copolymer, polyolefin,
Synthetic rubber, propylene, nitrile, isoprene,
It is a silicone-based, urea-based, phenol-based, or foam selected from or a mixture thereof.

In the shaft of the present invention, since the elastic body is easily deformed at the time of swing, it is preferable to increase the head speed at the time of swing by using an elastic material which greatly deforms at the time of swing. It is optimal to use it, especially at the tip of the shaft.

The method of filling the shaft with the elastic body is arbitrary, including forming the elastic body into a shape corresponding to the inside of the shaft and inserting the same. In the case where the mandrel is provided with the mandrel, the mandrel may be inserted into the shaft with the elastic body attached to the mandrel, or the mandrel may be fixed to the shaft, and then the elastic body formed into a shape corresponding to the inside of the shaft may be inserted. You may.

The mandrel and the elastic body may be inserted into the mandrel by inserting the mandrel into the elastic body, winding the mandrel around the mandrel, or forming the mandrel directly inside the shaft.

Table 1 (conventional products) and Table 2 show the results of measuring the ball initial speed and flight distance of golf clubs using the conventional shaft and the shaft of the present invention by the following methods.
(Invention of the present application).

Measurement method: A constant swing speed (50 m) was measured using a golf club swing mechanism manufactured by Miyama Co., Ltd.
/ S) to hit the ball, Bridgestone Sports Co., Ltd.
The initial speed (m / s) of the ball is measured by a ballistic measuring device manufactured by the Company, and the flight distance (carry) is measured from the speed by computer simulation.

The configuration of the club used is as follows: Shaft: Both the conventional product and the product of the present invention have the same length and the same number of carbon fibers of the same ply number.
5g thing. Club head: Loft angle 1 for both conventional and present products
0.5 degree, lie angle 55 degree, weight 193g. Elastic body (product of the present invention only) Material: Polyurethane foam Density: 0.3 (g / cubic cm) Asuka C hardness: 33 Rebound resilience: 50 (%) Residual compression: 4 (%) Usage: 30 cm at tip

[0029]

[Table 1]

[0030]

[Table 2]

From the above measurement results, the product of the present invention has a maximum ball speed of 6 m / s and an average of 3 m / s higher than the conventional product, and the configuration of the present invention is extremely effective in improving the initial speed of the ball. Proven to be. In addition, the flight distance is 42 meters at the maximum and 24 meters on average, which is significantly higher.

[0032]

According to the present invention, the shaft is filled with an elastic body which has a property of being easily deformed due to a strong repulsive force when a force is applied suddenly and being easily deformed when a gentle force is applied. As proved from the above measurement results, it is possible to provide a golf club shaft having an extremely improved initial ball speed and flight distance.

According to the fourth and fifth aspects of the present invention, excessive deformation of the shaft can be suppressed and repulsive force can be secured more effectively, so that further improvements in ball initial speed and flight distance can be expected.

According to the inventions of claims 6 and 7, the elastic body can also act on the deformation of the shaft in the torsion direction, which is extremely effective in stabilizing the directionality of the ball. The golf club shaft is extremely excellent not only in the initial ball speed and the flight distance but also in the directionality.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B show a golf club A using a golf club shaft 1 according to the present invention. Is shown. First, the configuration of the golf club A will be described.

The shaft 1 is a drawn sheet made of a high-strength high-elastic fiber impregnated with a synthetic resin (for example, carbon fiber), or a hollow structure wound with a high-strength high-elastic filament impregnated with a synthetic resin. It is. This structure is well known and will not be described in detail.

Reference numeral 2 denotes a club head, which is formed in a predetermined shape using a known material (for example, titanium), and has a shaft 1 inserted and fixed in a neck portion 3 provided integrally on the upper surface.

Reference numeral 4 denotes an elastic body, which is filled into the shaft 1 within a range of 30 cm from the upper end 31 of the neck portion 3 to the upper portion of the shaft 1, and the upper portion is provided with an adhesive 5.
Thus, it is bonded and fixed to the inner surface of the shaft over the entire circumference.

The elastic body 4 is a polymer material having a property that when a force is applied suddenly, a strong repulsive force acts thereon and the elastic body 4 is hardly deformed. .

An example of a method of filling the elastic body 4 will be described. The outer diameter of the elastic body 4 is formed to be larger than the inner diameter of the shaft 1 at the portion where the elastic body 4 is filled, and the adhesive is used. After application to a predetermined position, the shaft 1 is pushed from the upper end side or the lower end side (not shown) to be filled. Note that the filling method is not limited to the above-mentioned method, and it is optional to perform the filling by another method.

Next, with reference to FIGS. 2 and 3, a description will be given of a series of deformation states of the shaft 1 when the ball 6 is hit with the golf club A configured as described above.

First, at the time of a downswing, the shaft 1 is appropriate because the elastic body is easily deformed, and this bending increases the head speed.

Next, at the time of impact, as shown in FIG.
A shock D in the direction of the arrow C2 at the time of collision causes a couple D in the club head 2, and the couple D deforms the shaft 1 so as to crush the shaft 1 from the arrow E.

The time required for the shaft 1 to be deformed at the time of impact is about 100 to 1000 times faster than the time required for the shaft 1 to perform at the time of a downswing. Will be added.

At this time, the filled elastic body 4 is compressed along with the shaft 1 to be deformed, and a strong repulsive force is generated by the compression. This repulsive force minimizes the deformation of the shaft 1 due to the impact. And at the same time, the deflection of the shaft 1 is suppressed. That is, the loss of energy at impact is reduced, and the repulsive force of the shaft at impact is concentrated on the ball 6, so that the ball initial speed and the flight distance are improved.

Further, since the elastic body 4 is adhered to the shaft 1, a repulsive force acts on the shaft 1 even when the shaft 1 is deformed in the torsion direction, so that stable directionality is realized.

FIG. 4 shows a golf club A1 using another example of a shaft according to the embodiment of the present invention. In addition, the explanation about the part which overlaps with the above-mentioned example
The description is omitted by attaching the same symbol.

The golf club A1 of this embodiment has a shaft 1
And a mandrel 7 penetrating the elastic body.

The mandrel 7 is at least harder than the elastic body.
And a mandrel 71 having the same length as the entire length of the elastic body 4 using a material (for example, metal, carbon fiber, glass fiber, hard synthetic resin, or the like) having a tension enough to compress the elastic body. At the rear end of the mandrel, a fixing portion 72 having the same length as the entire length of the neck portion 3 is formed.

The mandrel 71 is formed in a thin rod shape and penetrates the elastic body 4 along the axis of the shaft 1. The fixing portion 72 is formed to have an outer diameter substantially conforming to the inner diameter of the shaft 1 corresponding to the neck portion 3, and is adhered and fixed by the adhesive 51.

Incidentally, one example of a method of filling the elastic body 4 in this embodiment will be described. The outer diameter of the elastic body 4 is formed to be larger than the inner diameter of the shaft 1 at the portion where the elastic body 4 is filled. At the same time, a through hole 41 through which the mandrel 71 penetrates along the axis thereof is opened. Then, the mandrel 7 is inserted into the through hole 41 from the lower end and attached, and an adhesive is applied to a predetermined position of the elastic body 4 and the fixing portion 72.
Alternatively, it is filled by pushing in from the lower end side (not shown).
Note that the filling method is not limited to the above-mentioned method, and it is optional to perform the filling by another method.

Next, with reference to FIGS. 2 and 5, a description will be given of a deformed state of the shaft 1 when the golf club A1 having the above-described structure hits the ball 6. FIG.

First, at the time of the downswing, the shaft 1 is appropriate because the elastic body is easily deformed similarly to the above-described example, and this bending increases the head speed.

Next, at the time of impact, as shown in FIG. 5, the ball 6 is applied to the club head 2 which advances in the direction of arrow C1.
A shock D in the direction of the arrow C2 at the time of collision causes a couple D in the club head 2, and the couple D deforms the shaft 1 so as to crush the shaft 1 from the arrow E.

At this time, the filled elastic body 4 applies a compressive force from the outside by the deformed shaft 1 to the shaft 1.
A compressive force acts from the inside by the mandrel 71 having a smaller deformation amount. That is, since the elastic body 4 is compressed from both the inside and the outside, a strong repulsive force is generated by the compression, and the repulsive force minimizes the deformation of the shaft 1 and the deflection of the shaft 1. Therefore, the loss of energy at impact is reduced, and the repulsive force of the shaft 1 at impact is concentrated on the ball 6, so that the ball's initial speed and flight distance are also improved by this example. .

In this embodiment, the golf clubs are all wood types. However, the golf clubs are not limited to the wood types, but may be iron types. In the case of this iron type (not shown), a long iron type used when a flight distance is required is optimal.

[Brief description of the drawings]

FIG. 1A is a partially cutaway side view showing a main part of a golf club using a golf club shaft according to the present invention. (B) is an enlarged sectional view taken along the line (b)-(b) of (a).

FIG. 2 is an operation diagram showing a deformed state of a shaft from a downswing to an impact.

FIG. 3 is a partially cutaway side view showing a deformed state of a shaft at the moment of impact.

FIG. 4A is a partially cutaway side view showing a main part of a golf club using a golf club shaft of another example according to the present invention. (B) is an enlarged sectional view taken along the line (b)-(b) of (a).

FIG. 5 is a cutaway side view of a main part showing a deformed state at the moment of impact in the shaft of FIG. 4;

FIG. 6 is an operation diagram showing a deformed state of the conventional shaft from a downswing to an impact.

FIG. 7 is a side view showing a deformation state of the conventional shaft at the moment of impact.

[Explanation of symbols]

 1: shaft 2: club head 3: neck 4: elastic body 5: adhesive 7: mandrel 71: mandrel 72: fixed part A, A1: golf club

Claims (7)

[Claims] An interior of a hollow shaft is filled with an elastic body that has a property of being hardly deformed by a strong repulsive force when a force is applied suddenly and easily deformed when a force is applied gently. Golf club shaft. 2. When a force is applied suddenly to a tip portion inside the hollow shaft, a strong repulsive force acts, so that the shaft is hardly deformed.
A golf club shaft filled with an elastic body having a property of being easily deformed when a gentle force is applied. 3. The golf club shaft according to claim 2, wherein the range of the tip portion filled with the elastic body is 30 cm to 40 cm from the end of the neck or the vicinity of the end. 4. A shaft having a built-in mandrel inside the shaft along its axis, wherein the mandrel has a lower end fixed to the tip of the shaft and a mandrel inserted into the elastic body. The golf club shaft according to any one of claims 1 to 3. 5. The golf club shaft according to claim 4, wherein the mandrel and the elastic body are bonded and fixed. 6. The golf club shaft according to claim 1, wherein the elastic body is bonded and fixed to the shaft. 7. The golf club shaft according to claim 1, wherein an upper end of the elastic body is bonded and fixed to the shaft.