JPH0642954A - Method and apparatus for measurement of bend condition of golf-club shaft - Google Patents

Abstract

PURPOSE:To obtain the measuring method, of a bend condition, wherein the bend condition of a club shaft can be grasped intuitively. CONSTITUTION:In the measuring method of the bend condition of a golf-club shaft, the golf-club shaft is arranged in the nearly horizontal X-direction, its grip side is fixed, a load is made to act on the side of its free end part, the club shaft is bent, and the point of intersection of a tangent line at the load point of a bend curve under its load or at a point nearer to the grip side than the load point with the x-axis is found. Then, the distance lambda from a specific point on the side of the fixed end part or on the side of the free end part of the club shaft up to the point of intersection is found, and the distance lambda is regarded as the representation amount of the bend condition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method and apparatus for measuring the bending condition of a golf club shaft.

[0002]

2. Description of the Related Art Bend values are conventionally known as a parameter expressing the deflection of a golf club shaft. The bend value is the maximum amount of displacement on the tip side when the butt (grip) side of the club shaft is fixed and a weight having a constant weight is suspended on the tip (head) side. The harder the material, the less the deformation. Therefore, the hardness can be expressed by the magnitude of the bend value. However, depending on this bend value, it is not possible to know the overall bending degree (bending condition) of the club shaft.

There is a concept of a kick point as another quantity for expressing the bending tone. This shows whether the most deformable part of the club shaft is on the tip side or the butt side.The bat side and tip side in the above-mentioned bend value measurement are exchanged, and a load is applied to the bat side to give the bend value. (Bat side bend value) is measured in the same manner. The ratio of this bend value to the above-mentioned bend value (chip side bend value) (butt side bend value / chip side bend value) is defined as a kick point. If this ratio is, for example, about 2.3, it is called middle tone, if it is larger (for example, 3.0), it is called first tone, and if it is smaller (for example, 1.8), it is called original tone. However, since this kick point is a dimensionless quantity and does not represent a length (distance), it is difficult to grasp intuitively.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bending tone measuring method and apparatus capable of intuitively grasping the bending tone of a club shaft.

[0005]

SUMMARY OF THE INVENTION The present invention is based on the idea that the bending angle (deflection characteristic) of a club shaft is measured as an amount that can be more intuitively grasped by utilizing the deflection angle at or near the load point. Is. According to the present invention, a golf club shaft is arranged in a substantially horizontal x-axis direction, its grip side is fixed, a load is applied to its free end side to bend the club shaft, and the flexure under load Find the intersection of the x-axis and the tangent at the load point of the curve or in the vicinity of the grip side from the load point, and determine the distance λ from the specified point on the fixed or free end side of the club shaft to this intersection. The feature is that this distance λ is used as the expression amount (parameter) of the bending tone.
Since the amount of expression of this bending tone has a dimension of distance (length), it is possible to intuitively grasp the easily bendable portion of the club shaft.

According to one aspect of the device of the present invention,
A means for arranging the club shaft in a substantially horizontal x-axis direction, fixing the grip side of the club shaft, and applying a constant load to a portion distant from the free end portion by a predetermined distance; a neutral shaft of the club shaft in an unloaded state From these, means for obtaining the force point and the displacement amount of the free end portion respectively; and these two displacement amounts, the distance S ₀ -Z from the fixed end to the force point, and the distance Z from the free end to the force point. Is used to approximate the λ / S ₀ ratio; and λ is a tangent line at the load point of the deflection curve of the shaft from the fixed end when the club shaft is subjected to the above load. It means the distance to the intersection that intersects the axis.

According to another aspect of the device of the present invention, the golf club shaft is arranged in the substantially horizontal x-axis direction, the grip side of the club shaft is fixed, and a constant load is applied to the free end portion. Means for determining at least two measurement points separated by a distance d from the force application point of this load to the grip side, and means for obtaining the amount of displacement from the x-axis to the two measurement points under load; and the two displacements. Means for approximating the λ / P ratio using the quantity, the distance P from the fixed end to the intermediate point between the two measurement points, and the distance d / 2 from the intermediate point to the two measurement points; Where λ means the distance from the fixed end to the intersection at which the tangent of the flexure curve of the shaft at the intermediate point intersects the x-axis when the load is applied to the club shaft. According to the above device, the λ / S ₀ ratio, the λ / P ratio, and the λ
Can be easily calculated and displayed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below with reference to the drawings. FIG. 1 shows a conceptual diagram of a method for measuring the bending tone of a club shaft according to the present invention. According to the method of the present invention, first, the club shaft 11 is held in the substantially horizontal x-axis direction, and the grip G side thereof is fixed to form a cantilever beam.
A constant load W is applied to the free end T of the club shaft 11 to bend the club shaft 11 (displacement amount δ). Although the deflection amount is exaggerated in the figure, the deflection amount at the time of actual measurement is small, and the deflection is assumed to occur in the direction perpendicular to the x axis.

In this flexed state, the tangent line V of the flexure curve D of the club shaft 11 at the load point T,
The intersection point R with the x-axis is obtained (deflection angle θ). Then, the distance λ of the intersection R from the fixed end G is used as the expression amount of the bending tone. Alternatively, the length (total length) from the fixed end G of the club shaft 11 to the free end T is S ₀ , and the ratio λ
Let / S _{0 be} another expression amount of curving tone. Therefore, as the distance λ and the ratio λ / S ₀ are larger, it means that the tone is sharper (the bendable portion is on the free end T side). Then, according to the distance λ and the ratio λ / S _0, it is possible to intuitively know the bending tone of the club shaft 11 based on the magnitude thereof.

According to the method of the present invention, as shown by the chain line in FIG. 1, due to the difference in the flexural rigidity distribution of the club shaft 11, a deflection curve D'which is sufficiently different on the grip G side from the free end portion (force application point) T is obtained. Even if it is obtained, there is an advantage that it can be evaluated as the same bending tone as long as the deflection angle θ and the displacement amount δ are the same. That is, since actual club shafts have different flexural rigidity distributions in the length direction, different flexural curves may be obtained even if the same flexure angle θ and displacement amount δ are shown. However, according to the expression amount λ of the bending tone of the present invention, even if the bending curves are sufficiently different on the grip G side from the force application point T, the club shafts having the same bending angle θ and the bending amount δ have the same bending tone. Can be evaluated as

This distance λ can also be obtained by calculation from the deflection amount δ, the deflection angle θ, and the total length S _{0 in} a small range of θ where θ (radian) ≈tan θ. That is, tan θ = δ / (S ₀ −λ) ≈θ S ₀ −λ = δ / θ λ = S ₀ −δ / θ λ / S ₀ = 1−δ / S ₀ θ

The total length S ₀ is the distance from the fixed end G to the load point T in this calculation formula, but S at the ratio λ / S ₀
The value of ₀ does not have to be exactly this distance, and the entire length of the club shaft 11 or the length in the vicinity thereof can be used.

Although the tangent line at the load point S has been discussed in the above description, the club shaft 11 can be regarded as a straight line in the vicinity of the load point when the load W (displacement amount δ) is small. Therefore, the grip G from the load point T
The tangent at a specific point on the side may be discussed, and the position (distance λ) at which this tangent intersects the x-axis may be used as the amount of expression of the bending tone.

Further, in the above embodiment, the fixed end G is the specific point for measuring the distance λ, but the specific point is, for example, the free end T, and the distance (length) from the free end to the intersection R. May be used as the amount of expression in a curved tone.

FIG. 2 shows a first embodiment of a measuring device for simply obtaining the λ / S ₀ ratio. This device applies a load W to a point T ₁ separated from the free end T of the club shaft 11 by a distance Z, and calculates the displacement amounts δ ₁ and δ ₂ from the x-axis at the force application point T ₁ and the free end T. It is measured by the displacement sensors 12 and 13. The displacement amounts δ ₁ and δ ₂ detected by the displacement sensors 12 and 13 are input to a calculator 14, where λ or (and) λ / is given by the following equation using known distances Z and S _0.
S ₀ is calculated and displayed on the display unit 15. λ = S ₀ −δ ₁ · Z / (δ ₂ −δ ₁ ) λ / S ₀ = 1− {δ ₁ · Z / (δ ₂ −δ ₁ ) · S ₀ }

FIG. 3 shows the principle of another measuring device. This device applies a load W to a load point T at the free end of the club shaft 11. In the range where the deflection is small, a constant short distance from the load point T to the grip G side can be regarded as a straight line. Grip that can be regarded as a straight line G
From the point T ₂ of length P to the measuring point T of a distance d / 2 in the front and back
₃ and T ₄ thinking, x in the measurement points T ₃ and T ₄
Assuming that the displacements from the axis are δ ₃ and δ ₄ , respectively, the curved tone expression amounts λ and λ / P can be obtained by the following equations.

Λ = P− {2 (δ ₃ + δ ₄ ) d} / (δ ₄ −δ ₃ ) λ / P = 1− {2 (δ ₃ + δ ₄ ) d} / (δ ₄ −δ ₃ ) P Specific measurement of δ ₃ and δ ₄ can be performed according to the apparatus shown in FIG.

[0018]

As described above, according to the method of the present invention, the bending tone of the club shaft can be intuitively measured. Further, according to the device of the present invention, the bending tone can be easily obtained by approximation calculation.

[Brief description of drawings]

FIG. 1 is a skeleton diagram illustrating the principle of a method for measuring the bending tone of a golf club shaft according to the present invention.

FIG. 2 is an explanatory diagram in which a specific example of a bending shaft measuring device for a club shaft according to the present invention is drawn by a skeleton.

FIG. 3 is an explanatory diagram in which another specific example of the method and apparatus for measuring the bending tone of the golf club shaft according to the present invention is drawn with a skeleton.

[Explanation of symbols]

11 Club shaft S ₀ Total length λ Distance (bending tone expression amount) D Deflection curve V Tangent line R Intersection point W Constant load 12 13 Displacement sensor 14 Computing unit 15 Display

Claims (5)

[Claims] 1. A golf club shaft is arranged in a substantially horizontal x-axis direction, its grip side is fixed, and a load is applied to its free end side to bend the club shaft. The intersection point between the tangent line at the load point of the flexure curve or the point near the load point on the grip side and the x-axis, and the distance from the specific point on the fixed end side or the free end side of the club shaft to this intersection point A method for measuring the bending tone of a golf club shaft, wherein λ is obtained, and this distance λ is used as an expression amount of the bending tone. 2. The club shaft according to claim 1, wherein the total length of the club shaft is S ₀ , the distance from the grip-side fixed point to the intersection is λ, and λ / S ₀ is another expression of bending tone. And how to measure the bending tone of the golf club shaft. 3. A step of arranging a golf club shaft in a substantially horizontal x-axis direction, fixing a grip side of the club shaft, and applying a load to a free end side thereof; The step of obtaining the intersection of the x-axis and the tangent line at the load point or a point near the grip side from the load point; and the distance from the specific point on the fixed end side or the free end side of the club shaft to this intersection point. A method for measuring the bending tone of a golf club shaft, the method including: a step of obtaining. 4. A means for arranging a golf club shaft in a substantially horizontal x-axis direction, fixing the grip side of the club shaft, and applying a constant load to a portion distant from a free end thereof by a predetermined distance; Means for obtaining the displacement amount of the force application point and the displacement amount of the free end from the neutral axis of the club shaft in the state; and the two displacement amounts and the distance S ₀ − from the fixed end to the force application point.
Using Z and the distance Z from the free end to the force applied point, λ / S
Means for approximating the ₀ ratio; where λ is the distance from the fixed end to the intersection point where the tangent line at the load point of the flexure curve of the shaft intersects the x axis when the load is applied to the club shaft; A device for measuring the bending tone of a club shaft, which is characterized in that 5. A means for arranging a golf club shaft in a substantially horizontal x-axis direction, fixing a grip side of the club shaft, and applying a constant load to a free end portion thereof; a grip side from an application point of this load. Means for determining at least two measurement points separated by a distance d from the x-axis to the displacement amount from the x-axis to the two measurement points under load; and these two displacement amounts and the two measurement points from the fixed end. Means for approximating the λ / P ratio using the distance P to the intermediate point and the distance d / 2 from the intermediate point to the two measurement points; where λ is
When the above load is applied to the club shaft, from the fixed end,
The tangent of the deflection curve of the shaft at the intermediate point is x
A device for measuring the bending tone of a club shaft, which is provided with a distance to an intersection that intersects the axis.