JP2000342725A - Iron club head - Google Patents

Abstract

(57) [Problem] To provide a club head for effectively correcting the tendency of a player who tends to bend a hit ball in a certain direction. SOLUTION: In a Cartesian coordinate system in which a point at which a shaft axis inclined at a prescribed lie angle (θ) intersects a ground line is set as an origin and a horizontal axis is a grind line passing through the origin, the height HG of the center of gravity of the iron club head is defined as HG. The relationship shown in the following equation (1) or (2) is set between and the center of gravity position XG from the toe end. Formula (1); HG ≧ (XG-L) tan (θ) + A, Formula (2); HG ≦ (XG-L) tan (θ) + B where (L) is the face length, and the A or B term is , The number determined by the number of clubs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the relationship between the direction of a hit ball of an iron club head and the position of the center of gravity.

[0002]

2. Description of the Related Art The position of the center of gravity of the head of a conventional iron club is, as shown in an embodiment described later, a ground line (horizontal ground) according to the results of actual measurements of various commercially available clubs performed by the inventor. With the point at which the shaft axis intersects as the origin, it is distributed about 30 mm in horizontal distance from the origin.

If the player hits the ball with the center of gravity of the head, the hit ball will fly straight if the face surface is perpendicular to the target direction. However, always striking at the position of the center of gravity of the head, that is, almost at the center of the face,
It is considerably difficult for a player of ordinary skill, and usually, the hit points are varied on the left and right of the center of gravity of the head. As a result, there is a problem that the flight trajectory of the hit ball bends right and left and the ball flies in an unintended direction. Particularly, for a player called a hooker or a slicer, which has a habit of always hitting a ball in a certain direction, a weight of a lead plate is pasted to the head on the toe or hill as a correction method. In general, measures are taken to change the position of the center of gravity of the head.

[0004]

On the other hand, regarding the position of the center of gravity and the directionality of the hit ball, if the center of gravity of the head is arranged close to the toe side on the face surface, the hit point is generally on the heel side from the position of the center of gravity. Therefore, it is said that the ball is turned into a so-called hook ball that flies leftward when the face surface rotates leftward with the center of gravity as a fulcrum due to the impact at the time of hitting the ball (right-handed). . Conversely, if the center of gravity of the head is moved to the toe side, when the club is swung, the face becomes difficult to return immediately before the hit and the hit ball flies to the right, a so-called slice bar.
It is also said that it will be. That is, conventionally, there is no established theory regarding the relationship between the position of the center of gravity on the face surface and the directionality of the hit ball.

[0005] Therefore, the measures against the bending of the hit ball must be made by trial and error, such as repeating the test hitting while changing the position where the weighted lead is applied in various ways. Furthermore, designing the club head itself in advance for the above-mentioned hooker or slicer can be a trial-and-error inefficient development under the current situation where there is no established theory regarding the center of gravity and the direction of the head. The sex is great. In view of such circumstances, an object of the present invention is to provide a club head that effectively corrects the tendency of a player who tends to bend a ball in a certain direction. .

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an iron club head according to the present invention is used for a player who has a tendency of hitting a ball to the left (in the case of right-handing). 1, the regular lie angle (θ)
In an iron club head that has a normal address posture by taking a loft angle, orthogonal coordinates are assumed with the point where the shaft axis intersects with the ground line as the origin and the ground line from this origin toward the toe side as the horizontal axis. do it,
The vertical distance from the ground line to the center of gravity of the head is the height of the center of gravity HG, the horizontal distance from the toe end to the center of gravity of the head is the center of gravity position XG, and the horizontal distance from the toe end to the origin is the face length (L ), There is a relationship expressed by the following equation (1) between the center of gravity height HG and the center of gravity position XG. Formula (1); HG ≧ (XG−L) tan (θ) + A where A is the number of clubs (N) and A = 1.
2N + 74.2.

In the above equation (1), as shown in FIGS. 4 and 5, a point at which a shaft axis inclined at a prescribed lie angle (θ) intersects a ground line is defined as an origin 0, and passes through the origin 0. In the orthogonal coordinates with the grind line as the horizontal axis and the vertical line to the ground line passing through the origin 0, the distance (XG-L) from the origin is taken in the horizontal axis direction, and the ground line is taken in the vertical axis direction. Height of the center of gravity from above (HG)
For each of the existing iron clubs, plot the coordinate values of the center of gravity for each count, and draw a line segment parallel to the shaft axis passing through the origin at a position close to the point plotted on the most toe side ( That is, HG = (XG-L) tan
When (θ) + A) is subtracted, it indicates that the position of the center of gravity of the club head according to the present application exists above this line segment. Hereinafter, the line segment parallel to the shaft axis is referred to as an (upper) limit line.

The term A in equation (1) is a value of the ordinate at a point where a line segment parallel to the shaft axis crosses the ordinate of the coordinate, as shown in each figure, and It is a numerical value that changes according to the formula A = 1.2N + 74.2 depending on the number (N). Note that the value of HG is a range of 5 mm in the horizontal toe direction from the (upper) limit line of the equation (1) because of the empirical restrictions on the shape and material of the head and the limit of shifting the position of the center of gravity to the toe side. Since it is preferable that A = 1.2 in the equation (1).
The value set as N + 74.2 + 5tan (θ) is set as the upper limit.

When swinging with the iron club head according to the first aspect of the present invention, the center of gravity of the head is located closer to the toe than the area where the center of gravity of the conventional product exists, ie, near the center of the face surface. In addition, as shown in FIG. 3, a so-called toe-down phenomenon in which the toe side of the head hangs down in the ground direction with respect to the shaft axis occurs, and
The ball has a posture (i.e., open) that is greatly opened with respect to the target direction of the hit ball. In other words, the dynamic lie angle becomes flat and the face opens, and as a result, the ball tends to fly rightward (in the case of right-handed),
The leftward flight of the so-called hooker, which always has a habit of hitting the ball to the left, is corrected, and a straight hit ball can be obtained.

Further, in the iron club head according to the present invention, in which the hit ball has a tendency to bend to the right (in the case of a right hit), for a player, a regular club is provided. In the iron club head having a lie angle (θ) and a loft angle and a normal address posture, a point at which the shaft axis intersects with the ground line is defined as an origin, and a ground line from the origin toward the toe side is defined as a horizontal axis. The vertical distance from the ground line to the center of gravity of the head is defined as the height of the center of gravity HG, the horizontal distance from the toe end to the center of gravity of the head is defined as the center of gravity position XG, and the horizontal distance from the toe end to the origin is assumed. Is the face length (L)
In this case, there is a relationship between the height HG of the center of gravity and the position XG of the center of gravity in the following equation (2). Equation (2); HG ≦ (XG−L) tan (θ) + B where B is the number of clubs (N) and B = 0.
67N + 60.3.

In this case, in the existing product plotted in the coordinate axis described in the equation (1), a line segment parallel to the shaft axis passing through the origin at a position close to the point plotted on the heel side. (That is, HG = (XG-L) ta
When n (θ) + B) is subtracted, it indicates that the position of the center of gravity of the club head according to the present application exists below this line segment. Hereinafter, the line segment parallel to the shaft axis is referred to as a (lower) limit line.

The term B in the equation (2) is the value of the ordinate at the point where the line segment parallel to the shaft axis crosses the vertical axis, as shown in FIGS. It is a numerical value that changes according to the formula B = 0.67N + 60.3 depending on the number (N). The value of HG is set at 5 mm from the (lower) limit line of the formula (2) to the heel side in the horizontal direction from the limit of shifting the position of the center of gravity to the heel side due to empirical restrictions on the shape and material of the head. Since it is preferable to be within the range, B in equation (2)
= 0.67N + 60.3-5tan (θ) is defined as the lower limit.

When the golf club swings with the iron club head according to the present invention, since the center of gravity of the head is changed closer to the hill than the region where the center of gravity of the conventional product exists, the dynamic lie angle (the club swings) (The lie angle when the ball is hit) is more upright than the conventional product, the degree of opening of the face is reduced, and the tendency of the hit ball to go to the left is strengthened. The right-sided ball muscle is corrected.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to FIGS. FIG. 1 shows a front view (a) and a side view (b) of a 5-iron head according to the present invention. A solid line A is Example 1, a solid line B is Example 2, and a broken line C is shown.
Indicates a head 1 of each club of a conventional product as a comparative example. Each club has a club length of 37.5 inches and a shaft to be mounted is R-flex.

First, in the club head 1 of the comparative example used as a reference for comparison, the face length (L) is 79.6 mm and the face width (M) is 51.8 mm. Represents 30.1 on the horizontal toe 3 side from the origin at a height of 20.1 mm from the origin on the coordinate axes described above.
It is arranged at a distance of 1.5 mm.

In the iron club head according to the first embodiment, as shown in the table of FIG. 2, the face length (L) is required to move the position of the center of gravity of the head 2 toward the toe 3 with respect to the conventional product of the comparative example. ) Is 7.4 mm and the face width (M) is 2.
It is set to be 2 mm larger. As a result, the center of gravity of the head 2
Is located at a height of 23 mm from the origin 0 and at a distance of 35 mm from the origin to the horizontal toe 3 side. Therefore, the center of gravity is shifted by 3.5 mm toe in the horizontal direction as compared with the comparative example.

In the second embodiment, the face length (L) is 4.6 mm and the face width (M) is different from the conventional product of the comparative example in order to move the position of the center of gravity of the head 2 toward the heel 4. Is set to be smaller by 0.4 mm. As a result ,
The position of the head center of gravity 2 is located at a height of 19 mm from the origin 0 and at a distance of 26 mm from the origin to the horizontal toe 3 side. Therefore, the center of gravity is shifted in the horizontal direction toward the heel of 5.5 mm from the comparative example.

A hitting robot performs a hitting test at a head speed of 40 m / s with respect to each club to which the above head is mounted, and shoots an image by a strobe photograph from a position where the swing surface is viewed at a right angle. The amount of bending of the shaft 5 shown was confirmed. The head of Example 1 had a deflection amount of 9.1 mm, which was 1.0 compared to the head of Comparative Example.
mm down head down. Therefore, the face 6 is opened to that extent, and the tendency to hit the ball in the right direction occurs. On the other hand, in the case of the second embodiment, the deflection amount is 7.1.
1.0 mm with respect to the head of the comparative example as a reference.
The lower the head down, the more. Therefore, the face 6 is closed as compared with the head of the reference club of the comparative example, and there is a tendency for the hit ball to fly to the left.

When the direction of the face 6 changed as a result of the toe-down was confirmed, the normal to the face 6 when the amount of deflection of the shaft was 8.1 mm in the club head of the comparative example was confirmed. On the basis of the case where the direction matches the target direction of the impact, in the case of the first embodiment, the normal direction set on the face 6 when the head of the first embodiment has a deflection amount of 9.1 mm is the aforementioned. It was observed that it was inclined rightward by about 0.7 degrees with respect to the normal direction of the reference. That is, in this case, it was observed that the face was turned right about 0.7 degrees, and in the case of Example 2, the face was turned left about 0.7 degrees. As a result, in the club of the first embodiment, the hit ball is extremely effective in correcting the hitting of a hooker having a tendency to fly to the left, and in the club of the second embodiment, the hitter has a habit of a slicer having a tendency to hit the right. It turns out that it is extremely effective in correcting the hit ball.

[0020]

By setting the center of gravity of the head within the range defined by the present invention, it is possible to effectively change the dynamic lie angle as compared with the existing club, which is a problem with the conventional club. It is possible to effectively correct a hooker or slicer having a habit in the direction of the hit ball. Also, in changing the dynamic lie angle, there is no need to change the rigidity of the shaft or the weight of the head, so there is no adverse effect on the swing timing and swing feeling, and further, the change of the lie angle of the club itself Since the address is not required, the feeling at the time of addressing is not adversely affected.

[Brief description of the drawings]

FIG. 1 shows a front view (a) and a side view (b) of an iron club head according to an embodiment of the present invention.

FIG. 2 is a table showing head specifications and characteristic values of an example and a comparative example.

FIG. 3 is a diagram illustrating the deflection of a shaft during a club swing.

FIG. 4 is a diagram showing the position of the center of gravity of the head of a No. 5 iron club.

FIG. 5 is a diagram showing the position of the center of gravity of the head of a ninth iron club.

[Explanation of symbols]

 1 Head 2 Head center of gravity 3 Toe 4 Heel 5 Shaft 6 Face

Claims (2)

[Claims] In an iron club head having a normal lie angle (θ) and a loft angle and a normal address posture, a point at which a shaft axis and a ground line intersect is defined as an origin, and the toe side is defined from the origin. The vertical distance from the ground line to the center of gravity of the head is assumed to be the height of the center of gravity HG, and the horizontal distance from the toe end to the center of gravity of the head is assumed to be the center of gravity position XG,
When the horizontal distance from the toe end to the origin is the face length (L), the height HG of the center of gravity and the position of the center of gravity XG
And an iron club head having a relationship represented by the following equation (1). HG ≧ (XG−L) tan (θ) + A where A = 1.2N + 74.2, where the club number is (N). 2. An iron club head having a normal lie angle (.theta.) And a loft angle and a normal address posture, the origin of which is the point where the shaft axis intersects with the ground line, and from the origin to the toe side. Assuming orthogonal coordinates having the ground line as the horizontal axis, the vertical distance from the ground line to the center of gravity of the head is defined as the center of gravity height HG, the horizontal distance from the toe end to the center of gravity of the head is defined as the center of gravity position XG, and When the horizontal distance to the origin is the face length (L), the height of the center of gravity HG and the position of the center of gravity XG
And an iron club head having a relationship represented by the following equation (2). HG ≦ (XG−L) tan (θ) + B where B = 0.67N + 60.3 where the club number is (N).