JP2001079123A - Iron club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the rotation of a head at the time of offset collision at impact, to improve directivity at the time of hitting of a ball and to increase a carry by making the plane ellipse when the spheroid centering at the centroid of a club head is virtually cut at a plane passing the centroid of the club head and paralleling to a loft angle nearly coincident with the variation distribution of the hitting points of general players. SOLUTION: A weight member having a specific gravity greater than the specific gravity of the metal constituting a head body 2 is fitted and integrated to the part from the upper part 8A at the front end of the toe of a peripheral edge weight arrangement part 7 in a back cavity part 6 and the central part of a sole part 9 to a heel part 10 of the iron club head 1 having a back cavity part 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron club head, and more particularly to an iron club head obtained when an inertial ellipsoid centered on the center of gravity of a club head is virtually cut along a plane passing through the center of gravity of the club head and parallel to the loft angle. An iron club that matches the plane ellipse with the distribution of hitting points of ordinary players, thereby suppressing the rotation of the head at the time of an offset collision in the event of an impact, improving the directionality at the time of hitting and increasing the flight distance. About the head.

[0002]

2. Description of the Related Art As a first conventional example of a conventionally known iron club head, there is one disclosed in Japanese Patent Application Laid-Open No. 7-67991. This passes through the center of gravity of the toe and hosel weight members by placing the center of mass above a horizontal axis drawn through the center of gravity of the club head when the golf club is lying at the address. A club head is disclosed that increases the moment of inertia about the horizontal and vertical axes.

As a second conventional example, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 9954 discloses that when an iron club head is installed on a plane, a plane formed by a tangential direction of the face surface and a direction perpendicular to the plane includes three principal axes of inertia whose origin is the center of gravity of the iron club head. An iron club head is disclosed in which the angle formed between the straight line projected in the tangential direction and the tangential direction is in the range of 10 to 40 °.

Further, as a third conventional example, Japanese Patent Application Laid-Open No. 1-300970 discloses a wood club in which the weight of the hosel portion is set to 5% or less of the weight of the head body and the length is set to 4%.
A wood club in which the principal axis of inertia is horizontal when the diameter is equal to or less than cm is disclosed.

As a method of improving the head directionality, a technique of increasing the moment of inertia of the head has been proposed as a fourth conventional example in which a hollow portion is provided inside an iron head body and the peripheral portion is thickened. It is a well-known fact that a so-called cavity structure or a hollow structure in which the inside of an iron head is completely hollow as a fifth conventional example is provided.

Further, as a sixth conventional example for improving the directionality of the head, a method of further improving the cavity structure, such as an iron head disclosed in Japanese Patent Application Laid-Open No. 9-329553, is to increase the thickness of the face portion. An iron head is known in which a thin amorphous metal is used as a face insert, and the weight of the thin portion is placed at the lower end of the toe of the head.

[0007]

Items required for a golf club include a flight distance and a directionality. In particular, the direction depends on the important factors related to fairway keeping and green keeping. The directivity largely depends on the position of the golf ball hit by the player. Apart from professional golfers and top amateurs, many general players hit golf balls at various positions on the golf head face, up, down, left and right. Therefore, when the golf ball collides with the center of gravity of the golf head, the directionality is good, but when the golf ball collides out of the center of gravity, the directionality deteriorates.

Accordingly, the moment of inertia of the head, particularly the moment of inertia in the toe heel direction when the club head is placed on a plane, is increased so that the directivity does not deteriorate even if the club head collides with the ball away from the center of gravity. A method has been proposed.

However, here, the magnitude and direction of the force at the time of collision between the golf club head and the golf ball will be considered. When hitting a golf ball with a golf club, as shown in FIG. 1, the club head receives a hitting force from the golf ball in the hitting direction. Since the golf club has a loft angle according to the count, the impact force F at the time of impact can be decomposed into a component force FH horizontal to the face surface and a component force FP perpendicular to the face surface as shown in FIG. The horizontal component force FH is a force for rotating the golf ball (producing back spin and side spin) together with the frictional force of the face surface. The vertical component force FP becomes a force for rotating the club face. When the hit point leaves the position of the center of gravity, the face rotates, and the directionality of the hit ball deteriorates.

Japanese Unexamined Patent Publication No. Hei 7-67991 cited as the first prior art discloses a method of increasing the moment of inertia. The club head is positioned at the center of the toe and hosel weight members. A club head that increases the moment of inertia about the horizontal and vertical axes passing through the center of gravity by positioning the center of mass above the horizontal axis drawn through the center of gravity of the golf club head when lying down. Therefore, there is a disadvantage that the moment of inertia in the direction perpendicular to the face surface is not increased.

[0011] Japanese Patent Application Laid-Open No. Hei 9 (1999) cited as a second conventional example.
Japanese Patent Application Laid-Open No. 149954 discloses that, when this club head is installed on a plane, a plane formed by a tangent direction of the face surface and a direction perpendicular to the plane has three principal axes of inertia having the origin at the center of gravity of the iron club head. Among them, there is disclosed an iron club head characterized in that an angle between a tangentially projected straight line and a tangential direction is in a range of 10 to 40 °.

However, in the second conventional example, only the direction of the principal axis of inertia is merely adjusted to the hit point distribution, and the moment of inertia perpendicular to the face surface for suppressing the rotation of the head at the time of hitting is merely described. I am not raising it.

Further, the distribution shape of the variation also varies in the vertical direction, and the shape changes depending on the number. Therefore, if only the moment of inertia in the variation direction is increased only indiscriminately, the variation in the vertical direction cannot be compensated for in the vertical direction. There is a drawback that variation in flight distance remains.

A point perpendicular to the face surface passing through the center of gravity of the club head is called a sweet spot. When the distance between the sweet spot and the hit point is increased, the head is easily rotated. In this method, only the principal axis of inertia centered on the center of gravity was considered, and especially when the loft angle was large, the sweet spot was located at a considerably higher position than the center of gravity, so the distance between the center of gravity and the hit point was adjusted. However, there is a drawback that the variation in directionality increases.

Further, in the golf club disclosed in JP-A-1-300970 cited as the third conventional example, the weight of the hosel portion of the wood club is set to 5% or less of the weight of the head body and the length is set to 4 cm or less. Thus, a wood club in which the principal axis of inertia is horizontal and the symmetry of the ball trajectory is ensured even when the sweet spot is removed, and the directionality is improved. However, this also has a good directionality with respect to the horizontal deflection of the head, but the hit ball distribution does not match the orientation of the main axis, and the variation in the flight distance in the ball line direction does not decrease so much as the variation in the vertical direction. There is a disadvantage that.

Further, in the technology for increasing the moment of inertia of the head, a so-called cavity structure has been conventionally provided in which a hollow portion is provided inside the iron head body and the peripheral portion is thickened. Although there is an effect of increasing the moment of inertia, there is a disadvantage that the effect of increasing the moment of inertia in the direction perpendicular to the face surface is small only by making the peripheral portion thicker unnecessarily. Similarly, the hollow structure described as the fifth conventional example also has the effect of increasing the moment of inertia, but this is also merely provided with a hollow part, and increases the moment of inertia in the direction perpendicular to the face surface. There is a disadvantage that the effect is small.

Further, Japanese Patent Application Laid-Open No.
In the golf club disclosed in JP-A-322295,
An iron head that uses a thin amorphous metal as the face insert member for the face part and the weight of this thin part is placed at the lower end of the toe of the head, so it can certainly distribute weight around the cavity. Although it has the effect of increasing the moment of inertia, if the process of processing the amorphous metal into the face insert member takes time, the cost of the co-amorphous metal itself is extremely expensive, so if it is commercialized as a golf club, it will be extremely expensive Had the problem mentioned.

Therefore, the main object of the present invention is to improve the inertia characteristics in the direction perpendicular to the face surface without increasing the moment of inertia in the horizontal direction and the vertical direction, and to improve the dispersion of the flight distance in the left-right direction and the flying ball line. An object of the present invention is to provide an iron club head in which the variation in the flight distance in the direction is reduced, the sweet spot and the center of the hitting point are made closer, and the reduction in the initial velocity of the ball is reduced.

[0019]

The invention according to claims 1 to 5 is an iron club head having a back cavity portion, wherein a peripheral weight arrangement portion of the back cavity portion is formed by an upper portion of a toe tip and a sole portion. The iron club head is characterized in that more is distributed and arranged in a portion from a center portion to a heel portion of the iron club head.

Further, a weight member having a higher specific gravity than the material of the head body is disposed in the upper portion of the toe tip and a portion from the center of the sole portion to the heel portion, and the shape of the peripheral weight disposing portion of the back cavity portion is changed. With an iron club head configured so that the height is gradually increased from the lower part of the tip to the back part of the heel of the sole part, so that the weight is arranged at the part from the center part of the toe tip upper part and the sole part to the heel part. is there.

Further, the shape of the peripheral weight arrangement portion of the back cavity portion is gradually increased from the lower portion of the toe tip to the back portion of the heel of the sole portion, and the sole width is increased from the lower portion of the toe tip to the heel portion. It is an iron club head characterized in that it gradually becomes smaller toward the portion.

[0022]

1 is a perspective view showing an iron club head having a back cavity portion according to a first embodiment of the present invention; An iron club head characterized in that a larger number of parts are distributed and arranged.

According to a second aspect of the present invention, there is provided an iron club head having a back cavity portion, wherein a portion extending from a central portion of the toe tip and a center portion of the sole portion to a heel portion of the peripheral weight disposition portion of the back cavity portion. An iron club head characterized in that a weight member having a specific gravity larger than that of a metal constituting the head body is fitted and integrated into the head body.

According to a third aspect of the present invention, there is provided an iron club head having a back cavity portion, wherein a portion extending from a center portion of the toe tip and a center portion of the sole portion to a heel portion of a peripheral weight disposing portion of the back cavity portion. An iron club head characterized in that a weight member having a specific gravity larger than that of a metal constituting the head body is fitted and integrated into the head body.

According to a fourth aspect of the present invention, there is provided an iron club head having the back cavity portion, wherein a shape of a peripheral weight arrangement portion of the back cavity portion extends from a lower portion of the toe tip to a heel back portion of the sole portion. , An iron club head whose height gradually increases.

According to a fifth aspect of the present invention, there is provided an iron club head having the back cavity portion, wherein a shape of a peripheral weight arrangement portion of the back cavity portion extends from a lower portion of a toe tip to a heel back portion of a sole portion. An iron club head characterized in that the height is gradually increased and the sole width is gradually reduced from the lower part of the toe tip to the heel part.

Next, FIG. 1 is a view for explaining the principle of the present invention. FIG. 1A is a view for explaining a striking force generated on a face surface when a golf ball 20 is hit with an iron club head 1. (B) is a view showing a state in which the face surface rotates at the time of impact and the golf ball 20 jumps out. In FIG. 1A, when the golf club 20 is hit with the iron club head 1, the golf club 20 hits the golf ball 20 with a striking force F at the striking position MP of the golf ball 20 with respect to the traveling direction of the swing.
Receive. In the golf club, the sole and the face are angled to change the launch angle of the golf ball 20 according to the count and obtain a flight distance for each count, and this angle is called a loft angle. Usually, it is set to about 10 ° for a driver, about 20 ° for a 3rd iron club, and about 40 ° for a 9th iron club, and the loft angle increases as the count increases.

The striking force F at the time of striking can be decomposed into a component force FH horizontal to the face surface and a component force FP perpendicular to the face because of the loft angle. The horizontal component force FH generates a force for rotating the golf ball 20 together with the frictional force of the face surface, that is, a back spin or a side spin. When the swing speed is high and the collision speed of the head is high, the striking force F increases, so that the horizontal component force FH also increases, and back spin and side spin are likely to be applied. It seems that the ball of an iron club such as a professional golfer soars upward after a shot and then falls vertically from the top, but this is due to the high head speed, backspin is applied, and This is because the ball rises and falls.

The vertical component force FP is a force acting perpendicular to the face surface as shown in FIG. 1B, and this force rotates the face. This rotation causes the ball after the shot to fly out in the left, right, up and down directions. On the other hand, a point at which a line drawn perpendicularly from the center of gravity G of the head to the face surface intersects the face surface is called a sweet spot SS. The sweet spot SS is the point where the golf ball flies the most, and if hit here, the head hardly rotates. However, when a general player makes a shot, he or she does not easily hit the sweet spot SS, but shoots around the sweet spot SS.

FIGS. 2 to 4 show the distribution of hit points of a general player. In particular, FIG.
FIG. 4 shows the hitting point distribution for a 9-iron. As apparent from FIGS. 2 to 4, it can be seen that a general player is hitting at various positions above and below and near the sweet spot SS. The player who has obtained this data has a golf score of around 100, and the circle mark in the figure indicates a dent on the face surface of the club head, the center of the hit point is indicated by a circle, and the 95% confidence interval. , The ellipse approximating the size and shape of the hit distribution is shown by a solid line.

Further, the solid line represents the A-axis passing through the center of the hit point on the face surface and parallel to the intersection line between the face surface and the ground, and the long axis of the ellipse approximating the variation of the hit point. From this result, the golf ball is hit at various points on the golf head face part, up and down, left and right, and it fluctuates in the left and right direction on the toe side and heel side, and also in the vertical direction on the leading edge side and the top edge side You can see that there is. This variation deteriorates the directionality of the ball after hitting the ball, so that an iron club head that maintains the directionality to some extent even if it fluctuates must be used.

On the other hand, as can be seen from the results of the hit point distribution, the hit point distribution has an elliptical shape having a long axis and a short axis. The angle formed by the angle in the long axis direction with respect to the intersection line between the cut surface and the ground is directed toward the upper side of the toe tip. Also, as the count increases, the angle of the major axis with respect to the line of intersection between the cutting plane and the ground gradually increases, and the shape gradually approaches a circle, and further, the center of the hit point from the ground It can be seen that the height has decreased as shown in FIGS. Thus, it can be seen that the hit point distribution shape of a general player has a specific tendency.

Here, the inertial resistance in the direction perpendicular to the face surface of the golf club was determined. 5 to 7 are views in which a golf club is set on a plane at a predetermined lie angle and loft angle.

In FIG. 5, the axis passing through the center of gravity G perpendicular to the ground is defined as the Z axis, and the axis parallel to the intersection of the tangent surface of the face center and the ground and passing through the center of gravity G perpendicular to the Z axis is defined as the Z axis. Let it be the X axis. An axis perpendicular to both the X axis and the Z axis and passing through the center of gravity G is defined as a Y axis.

First, as shown in FIG. 7, the direction vector of a plane parallel to the intersection of the tangent surface of the face surface with the ground and passing through the center of gravity is f (l, m, n) ^T. Calculate each vector of the expression.

F ₁ (l ₁ , m ₁ , n ₁ ) ^T = f × Z (0, 0, 1) ^T f ₂ (l ₂ , m ₂ , n ₂ ) ^T = f ₁ × f (1) f ₃ (l ₃ , m ₃ , n ₃ ) ^T = f ₁ × f ₂ where × represents an outer product.

Next, as shown in FIG. 6, an axis parallel to the intersection of the tangent surface of the face surface with the ground and the ground and passing through the center of gravity is an α axis, and an axis parallel to the surface and perpendicular to the α axis. Is the β axis, and the axis perpendicular to the α axis and the β axis is the γ axis, the conversion from the α, β, γ coordinate system to the X, Y, Z coordinate system is expressed by the following equation.

X = l ₁ · α + l ₂ · β + l ₃ · γ Y = m ₁ · α + m ₂ · β + m ₃ · γ (2) Z = n ₁ · α + n ₂ · β + n ₃ · γ where l ₁ and l ₂ , l ₃ , l ₁₂ , l ₁₃ , and l ₂₃ are X, Y,
Assuming the moment of inertia and the product of inertia about the Z axis, l ₁ · X ² + l ₂ · Y ² + l ₃ · Z ² + 2 · l ₁₂ · X · Y + 2 · l ₁₃ · X · Z + 2 · l ₂₃ · Y · Z = An ellipsoid represented by 1... (3) and Expression (3) is called an inertial ellipsoid. This indicates the magnitude of the inertial resistance in each direction. By substituting equation (2) into equation (3) and setting the term of γ to 0, equation (4) of the cut ellipsoid is obtained.

(I₁l₁ ^Two+ I_Twom₁ ^Two+ I_Threen₁ ^Two+ I₁₂l₁m₁+ I₁₃l₁n₁+ I_{twenty three}m₁n₁) Α^Two + (I₁l_Two ^Two+ I_Threem_Two ^Two+ I_Threen_Two ^Two+ I₁₂l_Twom_Two+ I₁₃l_Twon_Two+ I_{twenty three}m_Twon_Two) Β^Two + (I₁l₁l_Two+ I_Twom₁m_Two+ I_Threen₁n_Two+ I₁₂l₁m_Two+ I₁₂l_Twom₁+ I₁₃l₁n _Two ) + I₁₃l_Twon₁+ I_{twenty three}m₁n_Two+ I_{twenty three}m_Twon₁) Αβ = 1 (4) The size of this cut surface indicates the ease of rotation on this surface.
This indicates the magnitude of the inertial resistance, and
The section of the plane represents the vertical inertial resistance of that plane.
You. Further, as shown in FIGS. 6A, 6B, and 6C,
The shape of this cut surface is a three-dimensional inertial ellipsoid 30 and the cut surface of the surface.
Therefore, it is obvious that the plane ellipse is obtained.

Therefore, considering a golf club head, a plane ellipse obtained by cutting the inertial ellipsoid of the golf head at the face surface represents the rotation performance in the direction perpendicular to the face surface. Further, in the figure, a is the major axis length of the plane ellipse, b is the minor axis length, θ is the angle between the α axis and the major axis,
a / b is called an aspect ratio.

The hit point distribution of the general player shown in FIGS. 2 to 4 has an elliptical shape centered on the hit point center, and its major axis is directed toward the upper part of the toe tip. It is. That is, as shown in FIG. 2, in the case of the 3-iron, the angle of the long axis of the ellipse approximating the variation of the hit point with respect to the A-axis on the face surface is 5 °.
It is. Also, as shown in FIG. 3, in the case of the 6-iron, the angle of the long axis of the ellipse approximating the variation of the hit point with respect to the A-axis on the face surface is 7 °. Further, as shown in FIG. 4, in the case of the ninth iron, the angle of the long axis of the ellipse approximating the variation of the hitting point with respect to the A-axis on the face surface is 9 °.

Therefore, by making the center of the ellipse of a plane ellipse virtually cut at the face surface of the inertial ellipsoid substantially coincide with the sweet spot, the distance between the spot and the sweet spot due to the variation of the spot can be made as small as possible. In addition, since the rotation of the head can be suppressed and a shot is made in the vicinity of the sweet spot, the flight distance is increased by improving the ball speed.

Further, the angle of the plane ellipse in the major axis direction with respect to the line of intersection between the cut surface and the ground is matched with the angle of the player's hit point distribution toe tip toward the upper side, so that the horizontal deflection can be reduced. Can be suppressed. And by further matching the aspect ratio, which is the ratio of the major axis to the minor axis of the plane ellipse, with the elliptical shape aspect ratio of the hit point distribution of a general player, and substantially matching the inertial resistance in the vertical direction,
It is possible to suppress not only the variation in the horizontal runout in the left and right direction but also the variation in the flight distance in the flying ball line direction.

Therefore, as the count becomes larger, the angle of the major axis of the plane ellipse with respect to the intersection line between the cutting plane and the ground gradually increases, and the shape of the plane ellipse, that is, the major axis By gradually reducing the aspect ratio that is the ratio of the minor axis to the golf club set, the sweet spot is gradually lowered, so that any count can suppress the dispersion of the flight distance in the left and right direction and the ball line direction, As the speed of the ball improves, the flight distance increases.

[0045]

Next, specific examples of the present invention will be described. The embodiment of the present invention will be described with reference to FIG.
As shown in the figure, in the iron club head 1 having the back cavity portion 6, the peripheral weight disposing portion 7 of the back cavity portion 6 is moved from the toe tip upper portion 8A and the central portion 9A of the sole portion 9 to the heel portion 10 as shown in FIG. The iron club head 1 is characterized in that the iron club head 1 is more distributedly arranged in a region up to. As the head body 2 constituting the iron club head 1, stainless steel, pure titanium, a titanium alloy, or the like can be used. In this case, the peripheral weight disposition portion 7 of the back cavity portion 6, particularly the upper portion of the toe tip, is used. 8A
In addition, the thickness of the portion from the central portion 9A of the sole portion 9 to the heel portion 10 can be increased, or the weight distribution can be designed to be larger than designed.

The other embodiment of the present invention will be described, that is, as shown in FIG.
And the head body 2 is formed in a region from the toe tip upper portion 8A of the peripheral weight disposing portion 7 of the back cavity portion 6 and the central portion 9A of the sole portion 9 to the heel portion 10. An iron club head 1 in which a weight member 11 having a larger specific gravity than metal is fitted and integrated.

FIGS. 10A and 10B,
As shown in the cross-sectional views of (c), (d), and (e), the shape of the peripheral weight disposition portion 7 of the back cavity portion 6 extends from the toe tip lower side portion 8B to the heel back portion 10B of the sole portion 9. The iron club head 1 is characterized in that the height of the back 7A is gradually increased. As shown in the cross-sectional views of FIGS. 9B and 9E, the shape of the back 7A of the peripheral weight disposing portion 7 of the back cavity portion 6 is the lower portion 8B of the toe tip and the heel portion 1 of the sole portion 9.
0 is not a stand-up feature of the present invention. With this configuration, more weight can be distributed to the portion from the central portion 9A of the toe tip upper portion 8A and the sole portion 9 to the heel portion 10.

Further, FIGS. 10 (a) and 10 (b),
As shown in the cross-sectional views of (c), (d) and (e), the iron club head 1 is characterized in that the sole width 9W is gradually reduced from the lower part 9B of the toe tip to the heel part 10.

In more detail, one embodiment of the present invention will be described in detail. The head main body 2 is formed of pure titanium or a titanium alloy, and a tungsten alloy having a higher specific gravity than the head main body 2 is used as the weight member 11 for the back cabinet. Toe tip upper portion 8A and sole portion 9 of peripheral weight disposition portion 7 of tee portion 6
Can be press-fitted into a portion from the central portion 9A to the heel portion 10 to be fitted and integrated. The weight member 11 having a higher specific gravity than the head body 2 can be made of lead, beryllium copper alloy, brass or the like in addition to the above-mentioned tungsten alloy. It can be press-fitted into a portion from the central portion 9A of the sole portion 9 to the heel portion 10 of the toe tip upper portion 8A of the peripheral weight disposition portion 7 of the back cavity portion 6, and can be fitted and integrated.

The face part 3 and the back cavity part 6
The upper opening 7B of the peripheral weight disposing portion 7 is, for example, in the case of a 5 iron head, the distance from the back cavity 6 to the face surface 6A to the upper opening 7B is approximately 15 m.
m, the height of the back 7A of the peripheral weight disposition portion 7 of the back cavity portion 6 is 7 mm at a position 20 mm from the face center portion 3A to the toe portion side, and the face center portion 3A
9mm from face center 3A to heel 12mm
At a height of 12 mm. As a result,
The weight is disposed below the toe tip upper portion 8a and the heel portion 10, and the angle formed by the major axis direction of the plane ellipse with respect to the intersection line between the cut surface and the ground rises to the toe tip upper portion 8A, and Sweet spot decreases.

Next, the materials constituting the head body 2 are iron, stainless steel, aluminum, titanium, magnesium, tungsten, copper, nickel, zirconium, cobalt, and manganese which are commonly used in making a club head. , Zinc, silicon, tin, chromium, and other metal materials and alloy materials thereof, FRP, synthetic resin, ceramics, rubber, and the like. These materials may be manufactured from a single material, or two of these materials. It may be manufactured by a combination of the above. As a manufacturing method, the precision casting method is inexpensive in cost and has high dimensional accuracy, so that it is highly convenient. In addition, the head body can be manufactured by die casting, pressing or forging. On the other hand, parts are manufactured by pressing, forging, precision casting, metal injection, die casting, cutting, powder metallurgy, etc.
It is also possible to use a method of manufacturing a club head by bonding, pressing, screwing, brazing, or the like.

FIGS. 11 to 13 are diagrams for comparing variations in flight distance between the club head according to the embodiment of the present invention and the conventional club head. In particular, FIG. 12 shows an embodiment of the present invention, in which a flat ellipse is almost matched to the hit point distribution of a general player with a 3 iron having a loft angle of 21 °, and FIG. 13 shows a conventional club head. Is the case.

The test conditions are as follows. The golf robot sets the speed of the iron club head to 34.5 m / sec, and sets the hitting position in consideration of the variation of the hitting points of the general player as shown in FIG. C)
To toe tip (TM), toe tip upper part (TU),
Toe lower (TD), upper heel (HU), lower heel (HD), heel base (HM), upper center (CU), lower center (CD) This is the result of hitting at a distant position. Table 1 shows the specifications of the invention product and the conventional product.

[0054]

[Table 1]

On the other hand, the iron club head used for the measurement shown in FIG. 12 has the same weight (248 g) as the iron club head of FIG. 13, but the plane ellipse has an aspect ratio of 2.3 and a long axis direction. The angle formed by the angle with respect to the intersection line between the cut surface and the ground is 2 ° downward from the toe, and the center of the hit point is 20 mm. The results of the flight distance measurement test by the robot in FIG. 12 show that the variation in the right and left of the iron club head in FIG. 13 which is not matched with the hit point distribution of the general player is about 18 m, whereas the hit point distribution of the general player is a plane ellipse. 12 is about 15 m, which can reduce the variation of 17%.

On the other hand, the variation in the direction of the trajectory is about 24 m for the club head of FIG. 13 and about 13 m for the club head of FIG. 12, and the variation is reduced by 46%. Further, comparing the average flight distances, the club head of FIG. 13 is 155 m, while the club head of FIG.
It became 57 m, and the flying distance increased by about 2 m. In addition,
FIG. 12 and FIG. 13 show the average values when hitting the ball 11 times each.

Looking at the results of the impact on the upper part of the toe tip,
It can be clearly seen that there is a difference in rotation performance. That is, in the case of the club head of FIG. 13, the flight distance in the direction of the trajectory due to the impact of the upper portion of the toe tip is remarkable, and the ball falls to the right as compared to the average lateral displacement. 12
In the case of the club head, the flight distance is less reduced due to the impact on the upper end of the toe tip, and the side running is also reduced. This means that the rotation of the head is smaller in the iron club head in FIG. 12 than in the iron club head in FIG. 13, and it can be seen that the rotation performance of the head is superior.

[0058]

The present invention is characterized in that an advanced golfer can hit a ball with the feel of hitting like a conventional plain bag type iron club head with a thick back. In other words, the projecting portion formed on the face insert member allows the thickness of the face portion to be substantially increased, so that the feeling when hitting the ball is firm, and the feeling that the vibration when hitting is directly transmitted to the hand is felt. The golfer himself can satisfy feeling factors such as the strength of the hit golf ball itself and the strength of the hit golf ball, and can provide a low center of gravity and a wide sweet area at a low price. To play.

Further, according to the present invention, unlike the conventional iron club head, there is no need for a troublesome process for fitting a multi-stage face insert member.
Further, since it is not necessary to fit the weight members at a plurality of locations on the head main body, no trouble is involved in the manufacturing process, which leads to an increase in cost. Furthermore, even when the head body is manufactured by the precision casting method using lost wax, the number of these recesses for fitting is small, so that there is no possibility that the cast product of the completed head body itself is warped, and the yield can be improved. Was.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining the principle of an iron club head according to the present invention.

FIG. 2 is an explanatory diagram showing a distribution of hit points of a general player on a third iron.

FIG. 3 is an explanatory diagram showing a distribution of hit points of a general player on a 6-iron.

FIG. 4 is an explanatory diagram showing a distribution of hit points of a general player on a ninth iron.

FIG. 5 is an explanatory diagram for explaining an inertia ellipsoid and an X axis, a Y axis, and a Z axis of the iron club head according to the present invention.

FIG. 6 is an explanatory diagram for explaining an inertia ellipsoid and α-axis, β-axis, and γ-axis of the iron club head according to the present invention.

FIG. 7 is an explanatory diagram for explaining an inertia ellipsoid and a direction vector of the iron club head according to the present invention.

FIG. 8 is a perspective view showing an embodiment of the iron club head according to the present invention.

FIG. 9 is a perspective view showing an embodiment of an iron club head according to the present invention.

FIG. 10 is a perspective view showing another embodiment of the iron club head according to the present invention and portions AA to D in FIG. 10 (a).
Sectional drawing which shows the cross section of -D part.

FIG. 11 is an explanatory diagram showing a hitting position of the iron club head.

FIG. 12 is a graph showing the flight distance and variation of the iron club head according to the present invention.

FIG. 13 is a graph showing the flight distance and variation of a conventional iron club head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Iron club head 2 Head main body 3 Face part 3A Face central part 6 Back cavity part 7 Peripheral weight arrangement part 7A Back 7B Upper opening part 8 Toe part 8A Toe tip upper part 8B Toe tip lower part 9 Sole part 9A Central part 9W Sole width 10 Heel part 10B Heel back part 11 Weight member C Sweet spot T ・ M Toe tip part TU U Toe tip upper part TD Dee lower part H ・ U Heel upper part H ・ D Heel lower part H ・ M Heel base part Upper part of CU center Lower part of CD center 20 Golf ball 30 Inertia ellipsoid F Hitting force MP Hitting position FH Horizontal component FP Vertical component SS Sweet spot

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[Procedure amendment]

[Submission date] April 21, 2000 (200.4.2
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction contents]

On the other hand, the iron club head used for the measurement shown in FIG. 12 has the same weight (248 g) as the iron club head of FIG. 13, but has an aspect ratio of the plane ellipse of 2. 2. The angle between the major axis and the intersection line between the cut surface and the ground is 8 ° downward from the toe, and the center of the hit point is 20 mm. The results of the flight distance measurement test by the robot in FIG. 12 show that the variation in the right and left of the iron club head in FIG. 13 which is not matched with the hit point distribution of the general player is about 18 m, whereas the hit point distribution of the general player is a plane ellipse. 12 is about 15 m, which can reduce the variation of 17%.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kei Tsuji 1-12-35 Minami Kohoku, Suminoe-ku, Osaka-shi, Osaka F-term (reference) 2C002 AA03 CH04 LL01 MM04 PP03

Claims (5)

[Claims] 1. An iron club head having a back cavity portion, wherein a peripheral weight arrangement portion of the back cavity portion is more distributedly arranged in a portion from an upper portion of a toe tip and a center portion to a heel portion of a sole portion. An iron club head, characterized in that: 2. An iron club head having a back cavity portion, wherein a head main body is formed at a portion from an upper portion of a toe tip of a peripheral weight disposing portion of the back cavity portion and a center portion of a sole portion to a heel portion. An iron club head, wherein a weight member having a specific gravity greater than that of the metal to be fitted is integrated. 3. An iron club head having a back cavity portion, wherein a head body is formed at a portion from an upper portion of a toe tip of a peripheral weight disposing portion of the back cavity portion and a center portion of the sole portion to a heel portion. 2. The iron club head according to claim 1, wherein a weight member having a specific gravity greater than that of the metal is fitted and integrated. 4. An iron club head having the back cavity portion, wherein the shape of the peripheral weight disposition portion of the back cavity portion is gradually increased from a lower portion of the toe tip to a heel back portion of the sole portion. The iron club head according to claim 1, 2 or 3, wherein the height is increased. 5. The iron club head having the back cavity portion, wherein the shape of the peripheral weight arrangement portion of the back cavity portion is gradually increased from a lower portion of the toe tip to a heel back portion of the sole portion. 5. The iron club head according to claim 1, wherein the iron club head is formed to be high and the sole width is gradually reduced from the lower side of the toe tip to the heel.