JPH0547228B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the shape of the club face (striking surface) of a wooded golf club, and in particular, to a club face that can extend the flight distance when shot at a position below the standard hitting point. Regarding the shape of the roll.

In the case of a wood golf club, the face (hitting surface) of the club head fixed to one end of the shaft is formed of a convex curved surface. This curved surface is formed by a bulge having a horizontal radius of curvature (bulge radius) and a roll having a vertical radius of curvature (roll radius). Therefore, the normal direction at each point on the face is different.

Additionally, a reference hitting point (face center) is provided within the face for achieving an ideal shot.

Therefore, the shape of the bulge is related to the left and right launch angle, initial velocity, and side pin of the pole, and has a direct effect on the left and right wobbling of the ball's landing point.On the other hand, the shape of the roll related to the vertical launch angle, initial velocity and backspin,
It directly affects the vertical deflection in the vertical plane, including the trajectory of the ball.

The present invention relates to the shape of this roll, and FIG. 1 is a diagram showing the shape of a general roll.

In Figure 1, the tangent angles at each point on the roll, that is, the angles between the tangent and the vertical line, are all different, but among these tangent angles, the tangent angle θ at the reference hitting point (face center) C is the loft angle. It is called. This loft angle is appropriately selected within the range of, for example, 10 degrees to 25 degrees depending on the intended use of the club, and the number of the club is determined by selecting a plurality of loft angles for each predetermined angle.

However, in the case of conventional wood golf clubs, the roll has a single radius of curvature, for example, 127 mm (5 mm).
It is formed with a single roll radius within the range of 381 mm (15 inches) to 381 mm (15 inches), and given the roll radius at the reference point C (hereinafter referred to as the reference roll radius) and the loft angle θ, the tangent angle at each point is was to be determined uniquely. Therefore, when hitting a ball at a position away from the standard hitting point C, the launch angle, initial velocity, and amount of spin (backspin) are determined by the uniquely determined tangential angle, and the trajectory is also determined by this. It turns out.

On the other hand, when hitting the ball at a position away from the standard hitting point C, the tangential angle to ensure sufficient flight distance is determined by the physical characteristics of the club head (center of gravity, weight, moment of inertia, etc.) and the size of the loft angle. Except for special cases, it is impossible to ensure a sufficient flight distance by determining the distance uniquely as described above.

That is, the conventional face shape having a single roll radius has the disadvantage that if the hitting point deviates from the reference hitting point C, the flight distance cannot be increased sufficiently.

Although the deviation of the dot occurs both above and below the reference dot, the present invention is directed to the case where the dot shifts downward, that is, to the roll shape below the reference dot.

The present invention has been made in view of the problems of the prior art, and it is an object of the present invention to provide a wood golf club that can extend the flying distance at the hitting point position when the hitting point deviates downward from the reference hitting point. purpose.

The present invention uses kinematic analysis and experiments to explore the relationship between flight distance and tangential angle when the hitting point deviates downward from the reference hitting point, and the present invention makes it possible to increase flight distance even when the loft angle and player power differ. The above object is achieved by determining the range of tangential angles and forming the roll shape with a plurality of roll radii so as to obtain these tangential angles.

Regarding the player's power, the head speed of a professional golfer who makes strong shots is around 50 m/s (for example, 46 to 55 m/s).
s), and in the case of normal strength such as an ordinary adult male.
It is around 43m/s (e.g. 40-46m/s), and for weak people such as elderly people it is around 38m/s (e.g. 35-40m/s).
m/s) and varies considerably depending on the player.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 11.

Solid lines A, B, and C in FIG. 2 are graphs showing, for each loft angle, the optimum tangential angle at a position 10 mm below the reference hitting line, that is, the tangential angle at which the maximum flight distance at the relevant hitting point can be achieved. Line A is for head speed 50m/s, line B is for head speed 43m/s, and line C is for head speed 38m/s.
The case of m/s is shown respectively.

The dashed line D in FIG. 2 is a line indicating the tangential angle of a conventional club having a single roll radius (254 mm=10 inches).

The difference in loft angle is usually referred to as the difference in club number, with 9 to 13 degrees being #1, 14 to 18 degrees being #3, and 17 to 21.
degree corresponds to #4, and 20 to 24 degrees approximately corresponds to #5.

For conventional single roll radius clubs, if the impact point deviates to the bottom, for high club clubs with a loft angle of about 16 degrees or more, the tangential angle becomes excessive, the initial velocity decreases, and backspin becomes excessive. Therefore, there was a problem that a sufficient flight distance could not be secured. On the other hand, clubs for driver shots with a loft angle of about 10 degrees or less have a problem in that the tangential angle is too small, resulting in a low trajectory and an inability to secure sufficient flight distance.

For these reasons, even if the maximum flight distance could be maintained at the standard RBI point, if the RBI point deviated to the lower side, the launch angle, etc. would deviate from the appropriate value, resulting in the drawback that sufficient flight distance could not be secured at that RBI point. .

The inventors of the present invention have grasped these facts and have repeatedly investigated and experimented mechanically or kinematically, and as a result, below the reference hitting point, as shown by solid lines A, B, and C in Figure 2. It has been discovered that by providing a tangential angle, it is possible to extend the flight distance and approach the maximum flight distance compared to conventional clubs.

In other words, for a club with a loft angle above a certain value, by reducing the tangential angle by the amount shown in the figure and increasing the initial velocity by a predetermined amount, it is possible to increase the flight distance even when the head speed is different. It has been found that for a club with a small loft angle, flight distance can be increased by increasing the tangential angle and correcting the trajectory upward.

Figure 2 shows a standard roll radius of 254 mm (10 inches).
Big head speed is 50 m/s (solid line A), 43
m/s (solid line B) and 38 m/s (solid line C), this is a graph showing the most effective tangential angle for achieving the maximum distance for each loft angle, and in practice By setting the tangential angle within a predetermined range that includes the graph, it is possible to increase the flight distance when the hitting point deviates to the lower side than before.

Therefore, according to the present invention, the range of the roll radius is determined for each loft angle so as to obtain a tangential angle that can extend the flight distance when the ball deviates downward from the reference point as described above. Ru. As described above, these tangential angles can be set within a predetermined range including the graph of FIG. 2, so the roll radius can also be appropriately set within a range having a predetermined width. The larger the absolute value is, the wider the allowable range of this roll radius is, and the smaller the absolute value is, the narrower it is.

FIG. 3 is a graph showing roll radii A, B, and C corresponding to the tangent angles A, B, and C mentioned above. That is, solid lines A, B, and C in FIG. 3 correspond to solid lines A, B, and C in FIG. 2, respectively, and the standard roll radius is
254 mm is a graph showing the optimum roll radius for each head speed at a position 10 mm below the reference hitting point. Note that when determining the roll shape using these roll radii, the roll is usually formed by smoothly connecting the roll radius to the reference roll radius.

As is clear from Figure 3, the head speed
50m/s (solid line A), 43m/s (solid line B) and 38
The optimum roll radius in the case of m/s (solid line C) all have similar trends, decreasing as the loft angle increases, and tending to saturate to a constant value in the regions at both ends of the loft angle. ing.

Therefore, as shown by the two-dot chain lines placed above and below graphs A, B, and C in Figure 3, it is effective to extend the flight distance when shooting below the standard hitting point. You can set upper and lower limits for the roll radius.

From Fig. 3, the roll radius below the reference hitting point of the face is approximately the same as the reference roll radius (254 mm in the example shown) at a predetermined angle within the loft angle of 10 degrees to 18 degrees, and when exceeding the predetermined angle It can be seen that by making the radius smaller than the standard roll radius and making it larger than the standard roll radius below the predetermined angle, the flight distance when the hitting point deviates to the lower side can be extended compared to the conventional method.

In addition, the standard roll radius is approximately 254 mm (10 inches)
If the loft angle is 20 degrees or more, the roll radius should be set to 150 mm at a position approximately 10 mm below the reference hitting point.
If the loft angle is 10 degrees or less, it is preferable to set it to the standard roll radius or more.

Figure 4 is a graph showing the initial velocity of the ball when shot at a position approximately 10 mm below the reference hitting point, and solid lines A, B, and C are graphs shown in Figures 2 and 3, respectively.
The solid lines A, B, and C in the figure show the cases, and the chain lines near each solid line show the case of a conventional single roll radius (254 mm). From these graphs, it is also possible to confirm the state of change in initial velocity when changing to the optimum tangential angle at each head speed.

5 to 7 are graphs showing the amount of backspin corresponding to FIG. 4. Figure 5 shows head speed 50m/s, Figure 6 43m/s, Figure 7 38m/s.
The solid lines A, B, and C in each figure show the case of the optimum roll radius, and the dashed line shows the case of the conventional single roll radius. Of course, the dot position is 10mm below the standard dot. From these figures, it can be seen that the amount of backspin changes in response to changes in the tangential angle.

FIGS. 8 to 10 are graphs in which solid lines A, B, and C indicate flight distances when the present invention is implemented, and dashed lines illustrate flight distances when a conventional single roll radius is used. The hitting points are all approximately 10mm below the standard hitting point, and A has a head speed of 50.
m/s, B shows the case of 43 m/s, and C shows the case of 38 m/s.

From these graphs, it can be seen that if the roll radius is set as in the present invention, the flight distance will be longer than before for each loft angle (club number) even if the power of the player, that is, the head speed is different.

Although the present invention is directed to a wood golf club, it does not matter what kind of material it is made of as long as it has a conventional wood shape.

FIG. 11 is a graph showing the trajectory of the product according to the present invention in comparison with the trajectory of the conventional product. The solid line is for the product of the present invention, and the chain line is for the conventional product. Note that these trajectories were obtained when a club with a loft angle of 23 degrees was used and the shot was made with a head speed of 47 m/s and a point that was off to the bottom.

From this diagram, it is possible to clearly understand differences in ball trajectories such as launch angle and flight distance.

As is clear from the above description, according to the present invention, a club head is fixed to one end of the shaft, and the club head has a convex face surface and a loft angle of more than 18 degrees or less than 10 degrees. In a golf club, the standard roll radius at the standard impact point is in the range of 127 mm to 381 mm, and if the loft angle exceeds 18 degrees, the roll radius below the standard impact point is made smaller than the standard roll radius, and the loft is adjusted. When the angle is 10 degrees or less, the loft angle is changed so as to be larger than the reference roll radius, and the roll of the face is configured to have a plurality of smoothly continuous radii of curvature above and below the reference hitting point. Therefore, when shooting at a position below the standard hitting point, if the loft angle exceeds 18 degrees,
By reducing the tangential angle to reduce spin and increase initial velocity by a predetermined amount, distance can be increased, and for clubs with a loft angle of 10 degrees or less,
To provide a wooded golf club that can extend flight distance by increasing the tangential angle and correcting the trajectory upward.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the roll shape of the club head, Figure 2 is a graph showing the appropriate tangent angle below the standard hitting point along the loft angle, and Figure 3 is a graph showing the appropriate roll radius below the standard hitting point. Graph shown along the corner, Figure 4 is a graph showing the initial speed when using the club with the tangential angle of Figure 2 compared to the conventional product,
Figures 5 to 7 are graphs showing the amount of backspin when using a club with the tangent angle shown in Figure 2 compared to the conventional product at each head speed, and Figures 8 to 10
The figure is a graph showing the flight distance of the product of the present invention in comparison with the conventional product, and shows the trajectory for each head speed, and FIG. 11 is a graph showing the trajectory when shot with the product of the present invention in comparison with the conventional product. C...Standard hitting point (face center), R...
Standard roll radius, θ...loft angle.

Claims (1)

[Claims] 1. A club head is fixed to one end of the shaft,
In a wood golf club with a convex face surface formed on the club head and a loft angle of more than 18 degrees or less than 10 degrees, the standard roll radius at the standard hitting point is in the range of 127 mm to 381 mm, and the standard hitting point The lower roll radius is made smaller than the standard roll radius when the loft angle exceeds 18 degrees, and is made larger than the standard roll radius when the loft angle is 10 degrees or less according to the loft angle. A wood golf club characterized in that the roll of the face is formed with a plurality of smoothly continuous radii of curvature above and below a reference hitting point. 2. The standard roll radius is approximately 254 mm, and the roll radius at a position approximately 10 mm below the standard hitting point is 150 mm or less for loft angles of 20 degrees or more, and is larger than the standard roll radius for loft angles of 10 degrees or more. A wood golf club according to claim 1.