JP2826696B2 - Golf club shaft deflection characteristic measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a golf club shaft .
In which it relates to a device for measuring the deflection characteristics.

[0002]

2. Description of the Related Art It has been known that the bending characteristics of a golf club shaft (hereinafter, simply referred to as "shaft") have a great influence on the timing and feeling of a swing. As a method for examining the bending characteristics of the shaft, the Kenneth-Smith method shown in FIG. 5A is widely used. In the Kenneth-Smith method, the grip side 1a of the shaft 1 is held horizontally, a constant load W is applied to the head side 1b, and the maximum deflection (distance) Y caused by the load is defined as the deflection characteristic value of the shaft. However, as shown in FIG. 5B, the shaft 1 and the shaft 1A show the same evaluation value Y but have different bending curves, so that the actual bending during the swing is different between the two. . Therefore, when used by the player, the timing of the hit ball may be different, or the directionality of the hit ball may be adversely affected. That is, there is a disadvantage that a shaft having the same swing characteristics cannot be provided.

On the other hand, a measuring method for measuring a kick point Kp shown in FIG. 6 is also performed. The measurement of the kick point Kp is performed on the grip side 1a and the head side 1 of the shaft 1.
b, a compressive load Wp is applied from both ends of the shaft 1 along the axis S, and the bending characteristic is evaluated based on the position of a point Kp (kick point) on the shaft 1 which is farthest from the axis S. However, it is difficult to specify the kick point Kp, and therefore, it is not practical.

Therefore, conventionally, a measuring method for measuring the deflection of the shaft at a plurality of locations is known (for example,
Japanese Patent Publication No. 3-36172 and Japanese Patent Publication No. 74783). However, since the bending stiffness of the shaft does not change linearly and sometimes changes discontinuously, accurate bending characteristics cannot be obtained only by measuring the bending stiffness at a plurality of locations.

In both of the above prior arts, the bending stiffness is measured based on the bending of the shaft. However, since the shaft is flexible and has a large bending, the S / N ratio for the change in the measured bending is deteriorated. It is inevitable. Accordingly, accurate bending characteristics cannot be obtained.

In addition, the shaft is supported at a plurality of positions,
Since a lateral load (load perpendicular to the axis) is applied to the shaft, shear deformation occurs at the point of application. Further, since the shaft is a thin hollow rod, the cross section of the shaft is deformed at the fulcrum and the point of action. Thus, again, have a give to measure accurate bending stiffness.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an apparatus for measuring the bending characteristics of a golf club shaft enables accurate measurement of bending stiffness and measurement accuracy of the bending characteristics. The purpose is to improve.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, first, a first aspect of the present invention is a golf club.
With the bending moment applied to the shaft,
Along the axial direction of the club shaft.
The detection device moves while contacting the surface of the
Continuous detection of deflection or deflection angle of the club shaft
By calculating the bending stiffness of the golf club shaft,
With a measuring device to measure the deflection characteristics of golf club shaft
At least one end of the golf club shaft
Retaining beam that holds the golf club shaft on the side axis
And connect the golf club shaft and holding beam to one
It is supported by a support device in the state of a simple beam, and the load is
It is characterized in that a load applying device for acting is provided. This
Here, “continuously” means “the axis of the golf club shaft”.
Move while contacting the surface of the shaft along the line direction
Detection using a CCD camera.
It is intended to exclude those that are measured by a computer.

According to the first aspect of the present invention, the bending or the bending angle of the shaft can be continuously measured along the axial direction of the shaft, so that the bending rigidity of the shaft which changes in a complicated manner can be accurately measured. it can. The analysis can be easily performed using a computer.

Next, the relationship between the bending angle of the shaft and the bending rigidity is described.
The relationship will be described. Assuming that the deflection angle at an arbitrary point of the shaft is (dy / dx), the bending rigidity EI is calculated from the variation (d ² y / dx ² ) of the deflection angle by the following equation (1), as is well known. You can ask. EI = −M / (d ² y / dx ² ) (1) where M is the bending moment. Therefore, the bending rigidity can be obtained by measuring the amount of change in the deflection angle between two adjacent points .

Further, according to the first aspect of the present invention, since a load is applied to the holding beam connected to the shaft to apply a bending moment to the shaft, there is no need to apply a load directly to the shaft. Therefore, there is no possibility that cross-sectional deformation or shear deformation due to a lateral load will occur in the shaft.

On the other hand, the first and second holding beams for holding the shaft are continuously provided on the axial lines on both ends of the shaft, and the shaft and the two holding beams are connected by one simple line. A first and a second load applying device that is supported by a supporting device in a state of a beam and applies a load to both of the holding beams may be provided.

Further, it is preferable that the bending moment acting on the shaft is set to be smaller from the butt portion to the tip portion of the shaft by using the apparatus according to the first or second aspect of the present invention.

According to this measuring method, the bending moment is set so as to gradually decrease from the butt portion having a large bending stiffness to the tip portion having a small bending stiffness. M) changes are small. Therefore, since the deflection curve approaches a certain curvature, the measurement accuracy at each point on the axis of the shaft tends to be uniform .

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, a first holding beam 11 and a second holding beam 12 that hold the shaft 1 are continuously provided on the axis of the grip side 1 a and the tip side 1 b of the shaft 1, respectively. The two holding beams 11, 12
As shown in FIG. 2, the grip 1a or the tip side 1b is sandwiched between a pair of V-blocks 13, for example, so that the shaft 1 and both holding beams 11, 12 in FIG. It has a structure.

The support device 2 supports the shaft 1 and the holding beams 11 and 12 in a simple beam state as described below. The support device 2 includes a pair of left and right first support devices 21 and second support devices 22. The two support devices 21 and 22 are respectively provided by bearings 23.
While the shaft 1 is rotatable in the direction of the arrow, the shaft 1
I support. The second support device 22 is supported by a linear bearing 24 so as to be movable in the horizontal direction with respect to the base 20. Therefore, the beam 10 is shown in FIG.
As shown in (a), it is simply supported.
The first support device 21 shown in FIG. 1 slides on the base 20 by rotating the handle 25, and the support position can be changed according to the length of the shaft 1. I have.

The first holding beam 11 is attached to the base 20.
And the first lateral load W _{1 on} the second holding beam 12, respectively.
And first and second load applying devices 31, 32 for applying a _second lateral load W2. The two load applying devices 31 and 32 are connected to the suspension members 3 via bearings 33 rotatably fixed to the holding beams 11 and 12 in the direction of the arrow.
4 and the box 35 are suspended. The weights 36 and 37 provided in the box 35 are supported by a lifting device 38, and the weights of the weights 36 and 37 are added to the holding beams 11 and 12 by lowering the lifting table 39.

A detection device 40 is slidably provided on the base 20. The detection device 40 has a detection elevating table 41 that is vertically movable with respect to a mast 42.

In FIG. 3, in the case of the present embodiment, the detecting device 40 moves along the axial direction of the shaft 1 to continuously detect the deflection angle θ of the shaft 1 as described below. Things. The detection lift 41 is provided with a displacement sensor 47, and a tilt tracer 45 is rotatably attached to a pin 44 at the lower end of the support bar 43. The tilt tracer 45 has a pair of rollers 46, 46. When the detecting device 40 moves left and right, both rollers 46, 46
Move while touching f. Therefore, the inclination of the surface of the inclination tracer 45 becomes a value approximate to the bending angle of the beam 10.

The displacement sensor 47 includes a tilt tracer 45.
The vertical displacement dh of the free end portion 45a is measured by measuring the vertical distance to the free end portion 45a, and the displacement dh is measured.
Is output to a microcomputer (hereinafter referred to as “microcomputer”) 50 built in a personal computer (not shown). On the other hand, the microcomputer 50 receives the movement amount from a rotary encoder 51 that measures the movement amount of the detection device 40 in the horizontal direction. As described below, the CPU 52 of the microcomputer 50 determines the shaft 1 based on the change in the bending angle θ.
Computing means for calculating the bending stiffness EI in each part of the above.

In FIG. 4A, a bending moment M at an arbitrary point C on the shaft 1 is expressed by the following equation (2). M = L ₁ (W ₂ −W ₁ ) · x / L ₃ + L ₁ W ₁ (2) where L ₁ ≦ x ≦ L ₃ −L ₁ L ₁ : Load W ₁ or W ₂ from point A or B L ₃ : Length of beam 10 x: Distance from point A to point C

On the other hand, the relationship between the bending rigidity EI and the bending moment M is expressed by the following equation (1). EI = −M / (d ² y / dx ² ) (1) where dy / dx: deflection angle (see FIG. 4B). The deflection angle dy / dx is expressed by the following equation (3). Is done. dy / dx = tan ^-1 (dh / La) (3) where La is a horizontal distance corresponding to the height dh in FIG.

Therefore, the height d at two adjacent points
By measuring h, the change in the deflection angle (d ² y / dx
By knowing ² ), the bending rigidity EI along the axial direction of the shaft 1 can be obtained. The CPU 52 in FIG.
The obtained bending rigidity EI is stored in the memory 53 and output from output means such as the CRT 54 and the printer 55.

Next, a measuring method will be briefly described. FIG.
The lifting table 39 is raised, and the weights 36 and 37 are
The detector 40 is moved over the entire length of the shaft 1 in a state where no load is applied, and the vertical position of the upper end surface of the shaft 1 is detected by the displacement sensor 47 (FIG. 3). The position in the horizontal direction is detected by the rotary encoder 51 of FIG. 3, and these detected values are stored in the memory 53 of the microcomputer 50. Subsequently, after lowering the elevator 39 of FIG. 1 to apply the lateral load by the weights 36 and 37 to the first holding beam 11, the vertical position of the shaft 1 is detected and detected in the same manner as described above. The horizontal position of the elevator 41 is detected. Thus, the bending stiffness EI of the reference shaft 1 is obtained by expressing the bending stiffness EI by the function of the distance x or (x−L ₁ ) = x ₁ in FIG. 4B. Based on the bending stiffness EI, a shaft is produced or an inspection is performed by comparing the bending stiffness of the produced shaft with a reference shaft bending stiffness.

The shaft 1 is connected to the grip side 1a.
From the tip side 1b, the diameter becomes smaller, and the steel shaft has a stepped portion. for that reason,
The bending stiffness EI does not change linearly, but shows a discontinuous and quadratic or higher curve change.

On the other hand, this measuring device uses the shaft 1
Along the axial direction of the shaft 1 (dy / d
x) can be measured continuously, that is, since the number of measurement points is large or infinite, the shaft 1 that changes in a complicated manner
Can be accurately measured. Therefore, the bending characteristics of the shaft 1 can be accurately measured.

By the way, since the shaft 1 is flexible, the deflection y of the shaft 1 shown in FIG. Here, when the deflection y which greatly changes is directly detected, the deflection y
Is too large, the detection accuracy of the change in the deflection y is deteriorated. That is, the S / N ratio deteriorates. Here, in the present embodiment, the inclination (dh / L) as shown in FIG.
Since a) is required, the S / N ratio is improved. Accordingly, accurate bending characteristics can be obtained.

Since the deflection of the shaft 1 is extremely large, each point of the shaft 1 is greatly displaced in the axial direction. Therefore, it is necessary to express the bending rigidity EI as a function of x based on the above-mentioned equations (1) to (3) in consideration of the displacement in the axial direction.

In this embodiment, the two holding beams 1 shown in FIG.
A bending moment is applied to the shaft 1 by applying a lateral load to the shafts 1 and 12. Therefore, since a lateral load is not directly applied to the shaft 1, cross-sectional deformation or shear deformation of the shaft 1 due to the lateral load hardly occurs. As a result, the bending rigidity EI of the shaft 1 can be accurately known.

In this embodiment, since the first and second load applying devices 31 and 32 are provided, the weight 36 is
7 or the length L ₁ , ₁ in the first and second holding beams 11 and 12 in FIG.
By making L ₁ different from each other, the bending moment can be set to be smaller as going from the butt portion 1d of the shaft 1 to the tip portion 1e as shown in FIG.
Therefore, from the butt portion 1d having a large bending rigidity EI,
Since the bending moment M gradually decreases toward the tip portion 1e having a small bending rigidity EI, the change in (EI / M) over the entire length of the shaft 1 decreases. As a result, the deflection curve approaches a certain curvature, so that the measurement accuracy at each point of the shaft 1 tends to be uniform.

As described above, in this measuring apparatus, the shaft 1
The bending stiffness of each part can be accurately examined, and unlike the past, there is no unique mechanical setting, so it is possible to accurately and easily compare shafts based on the measured bending stiffness In addition to this, comparison with bending stiffness measured by another measuring device becomes possible.

In this embodiment, both holding beams 1 shown in FIG.
Although a lateral load is applied to the shafts 1 and 12, in the present invention, a bending moment may be applied to the shaft 1 by applying a bending moment to both of the holding beams 11 and 12 using a motor or the like.

In this embodiment, a pair of holding beams 11,
In the first aspect of the present invention, for example, the first
May be provided, and the load applying device 31 may apply a lateral load to the holding beam 11.

In this embodiment, the displacement sensor 4 shown in FIG.
The deflection angle was measured by 7 and the tilt tracer 45.
In the present invention, rather than the deflection angle, by measuring the deflection, but it may also be asked to bending rigidity EI.

[0035]

As described above, according to the present invention ,
Since the bending or the bending angle of the shaft can be continuously measured along the axial direction of the shaft, the bending rigidity of the shaft, which changes in a complicated manner, can be accurately measured. Therefore, the measurement accuracy of the bending characteristics of the shaft is improved. Moreover, since it is possible to obtain a continuous bending stiffness based on the bending stiffness, Ru can be compared of the shaft cross accurately and easily. In particular, the present invention, and continuously provided to hold the beam to the shaft, so adding load to the holding beam, deformation of a section along a lateral load is not Na occurs in the shaft.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a measuring apparatus showing one embodiment of the present invention.

FIG. 2 is a perspective view illustrating a method of holding a shaft.

FIG. 3 is a schematic configuration diagram illustrating a detection device.

FIG. 4A is a conceptual diagram showing a supported state of a shaft,
(B) is a conceptual diagram showing a bending curve of a shaft, and (c) is a bending moment diagram.

FIG. 5 is a conceptual diagram showing the Kenneth-Smith method.

FIG. 6 is a conceptual diagram illustrating a kick point method.

[Explanation of symbols]

 1: Shaft 1d: Butt part 1e: Tip part 2: Supporting device 11: First holding beam 12: Second holding beam 31, 32: Load applying device 40: Detection device

Claims (2)

(57) [Claims] 1. A bending moment applied to a golf club shaft.
In the axial direction of the golf club shaft
Along with the surface of the golf club shaft
The deflection of the golf club shaft by the moving detection device
Or, by continuously detecting the deflection angle, the golf club shuffling
Golf club shaft deflection by determining the bending stiffness
A measuring device for measuring only characteristics, wherein a holding beam for holding the golf club shaft is continuously provided on an axis of at least one end of the golf club shaft, and the golf club shaft and the holding beam are formed of one simple beam. A deflection characteristic measuring device for a golf club shaft, further comprising a load applying device which is supported by a supporting device in a state and applies a load to the holding beam. 2. A bending moment applied to a golf club shaft.
In the axial direction of the golf club shaft
Along with the surface of the golf club shaft
The deflection of the golf club shaft by the moving detection device
Or, by continuously detecting the deflection angle, the golf club shuffling
Golf club shaft deflection by determining the bending stiffness
A first and second holding beams for holding the golf club shaft are connected to each other on an axis at both ends of the golf club shaft, and the golf club shaft and the two holding beams are connected to each other. A deflection characteristic measuring device for a golf club shaft, comprising first and second load applying devices that are supported by a supporting device in a state of one simple beam and apply a load to the both holding beams.