JP2001161869A - Iron club head - Google Patents

Abstract

(57) Abstract: The present invention relates to an iron club head, and in particular, an inertial ellipsoid centered on the center of gravity of the club head is virtually cut by a plane passing through the center of gravity of the club head and parallel to the loft angle. By making the ellipse of the time almost match the distribution of the hit points of the general player,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron club head capable of suppressing rotation of a head at the time of an offset collision at the time of impact, improving directionality at the time of hitting a ball, and increasing a flight distance. SOLUTION: To describe an iron club head according to the present invention, a back cavity type iron in which a concave portion 2A is formed in a back face portion 2 of a head main body 1A and a peripheral edge weight portion 3 is formed on a peripheral edge of the concave portion 2A. In the club head 1, a weight addition portion 5 </ b> B is formed at the toe upper end portion 5 </ b> A of the peripheral weight portion 3, and the height of the portion from the central portion 6 </ b> B on the sole portion 6 side of the peripheral weight portion 3 to the heel portion 8. An iron club head 1 in which a lower weight adding portion 6A having an increased height is formed.

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 disclosed in Japanese Patent Application Laid-Open No. 7-67991 as a first conventional example of a conventionally known iron club head, a golf club is provided with an address at the center of weights of a head portion and a hosel portion. An iron club head that increases the moment of inertia about the horizontal and vertical axes through the center of gravity by positioning the center of mass above the horizontal axis drawn through the center of gravity of the club head when lying down Is disclosed.

Further, 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, in a wood club head, as disclosed in JP-A-1-300970, 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 cm or less. By doing so, a wood club having a horizontal principal axis of inertia is already known.

Further, 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, a hollow portion is provided inside a head body of an iron club head, and a peripheral portion is formed. It is a well-known fact that a so-called cavity structure in which the thickness is increased, or a hollow structure in which the inside of the head body of the iron club head is completely hollow as a fifth conventional example is provided.

[0006]

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 hitting position of the golf head when the player hits the ball. Apart from professional golfers and top amateurs, most general players play golf at various positions on the golf club head, such as up, down, left and right. Hitting the ball.

For this reason, when the golf ball collides with the center of gravity of the golf head, the directionality is good. However, when the golf ball collides with the center of gravity, the directionality is deteriorated.

Therefore, the moment of inertia of the head, especially the moment of inertia in the 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 way to do that 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 ball with a golf club, the club head receives a hitting force from the ball in the hitting direction as shown in FIG.

Since the golf club has a loft angle depending on the iron count, the impact force F at the time of impact can be divided 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 serves as a force for rotating the ball (producing back spin and side spin) together with the frictional force on the face surface.

The vertical component force FP is a force for rotating the club face. When the hit point leaves the position of the center of gravity, the face is rotated, and the directionality of the hit ball deteriorates.

Japanese Unexamined Patent Publication No. 7-67991 cited as the first prior art discloses a method of increasing the moment of inertia. A club head is provided at the center of the weight members of the toe portion and the hosel portion. A club head that increases the moment of inertia about the horizontal and vertical axes 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 at the address Therefore, there is a disadvantage that the moment of inertia in the direction perpendicular to the face surface is not increased.

Further, Japanese Patent Application Laid-Open No.
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 increased. It was not.

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 unnecessarily, the variation in the vertical direction cannot be compensated for in the vertical direction. There is a disadvantage that the flight distance varies.

A point that passes through the center of gravity of the club head and intersects perpendicularly with the face surface is called a sweet spot. When the distance between the sweet spot and the hit point is increased, the head is more likely to rotate. 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 directional variation increases.

Further, in Japanese Patent Laid-Open Publication No. 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. The main axis of inertia is horizontal and the symmetry of the ball trajectory is secured even if the sweet spot is removed,
A wood club with improved directionality is disclosed. 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 was a disadvantage.

Further, in the technology for increasing the moment of inertia of the head, a so-called cavity structure is conventionally provided in which a hollow portion is provided inside the iron head body and the peripheral portion is thickened. Although it has the effect of increasing the moment, 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 edge 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 was a drawback that the effect was small.

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.

[0022]

SUMMARY OF THE INVENTION The present invention relates to a back cavity type iron club head in which a concave portion is formed in a back face portion of a head body and a peripheral weight portion is formed on a peripheral edge of the concave portion. A weight addition portion is formed at the upper end of the toe of the weight portion, and a lower weight addition portion is formed in which the height of a portion from the center portion on the sole portion side to the heel portion of the peripheral weight portion is increased. Iron club head.

[0023]

FIG. 1 is a diagram for explaining the principle of the present invention, and FIG. 1A is a diagram for explaining a striking force generated on a face surface when a golf ball is hit with a club head. FIG. 1B is a diagram showing a state in which the face rotates and the ball jumps out when hit.

In FIG. 1A, when hitting a ball with a golf club, the club head 1 receives a hitting force F from the ball 20 in the direction of the swing at the hitting point of the ball. In the golf club, the sole and the face surface are angled in order to change the projecting angle of the ball 20 according to the count and obtain a flight distance for each count, and this angle is called a loft angle. Usually one with a driver
The loft angle is set to about 0 °, about 20 ° for the 3rd iron, and about 40 ° for the 9th iron, 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. This horizontal component FH is a force that rotates the ball 20 together with the frictional force of the face surface,
That is, back spin and side spin are generated. 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 such as a professional golfer soars upward after the shot and then falls vertically from the top.However, because of the high head speed, the backspin is applied and the ball Is to rise and fall.

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 golf ball after the shot to fly out in the left, right, up and down directions.

On the other hand, a point where a line drawn perpendicularly to the face surface from the center of gravity G of the head intersects the face surface is called a sweet spot SS.

This sweet spot SS is the point where the ball flies the most, and if hit, the head hardly rotates. However, when a general player made a shot, the sweet spot SS was not easily hit, and in most cases, shots were made around the sweet spot SS.

FIGS. 2 to 4 are diagrams showing the distribution of hit points of a general player. In particular, FIG.
FIG. 4 shows the hitting point distribution for a 9-iron.

As is apparent from FIGS. 2 to 4, it can be seen that a general player is hitting at various positions above and below, near the sweet spot SS, and on the left and right. The player who has obtained this data has a golf score of about 100, and the circle in the figure indicates a dent on the face surface of the club head, the center of the hit point is indicated by a dot, and a 95% confidence interval is shown. , 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 these results, it can be seen that the golf ball is hit at various points on the golf head face, up and down, left and right, and also in the left and right directions on the toe side and the heel side, and in the vertical direction on the leading edge side and the top edge side. It can be seen that there is some variation. Because of this variation, the directionality of the golf ball after hitting is deteriorated. Therefore, it is necessary to use an iron club head that maintains the directionality to some extent even if it fluctuates.

On the other hand, as can be seen from the result of the hit point distribution, the hit point distribution has an elliptical shape having a major axis and a minor axis. The angle formed by the angle in the long axis direction with respect to the line of intersection between the cut surface and the ground is upward of the toe.

As the count increases, the angle of the major axis with respect to the line of intersection between the cut surface and the ground gradually increases, and the shape gradually approaches a circle. It can be seen that the height from the ground 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.

FIG. 5 to FIG. 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 passing through the center of gravity G perpendicular to the Z axis and parallel to the intersection line between the tangent surface of the face center and the ground and the ground. 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 line of intersection between the tangent surface of the face surface and the ground and passing through the center of gravity is f (l, m, n) ^T. Each vector of the equation is calculated by Equation 1.

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 at the centroid 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 Equation 2.

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 Equation 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. 6 (a), 6 (b) and 6 (c), since the shape of the cut surface is a three-dimensional inertial ellipsoid and a cut surface of the surface, it is apparent that the cut surface is a plane ellipse. It is.

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. 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, and a / b
Is called an aspect ratio.

Here, 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 the major axis thereof is directed to the toe upward. That is, as shown in FIG. 2, in the case of the 3-iron, the toe upward angle of the major axis of the ellipse approximating the variation of the hit point is 5 ° with respect to the A-axis on the face surface. Further, as shown in FIG. 3, in the case of the 6-iron, the toe upward angle of the major axis of the ellipse approximating the variation of the hit point is 7 ° with respect to the A-axis on the face surface. Further, as shown in FIG. 4, in the case of the 9-iron, the toe upward angle of the major axis of the ellipse approximating the variation of the hit point is 9 ° with respect to the A-axis on the face surface.

Thus, 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 reduced as much as possible. , The rotation of the head can be suppressed,
Because you will be shooting near the sweet spot,
As the ball speed increases, the flight distance increases.

Further, by adjusting 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 to the upward angle of the hit point distribution toe of the player, it is possible to suppress the lateral displacement in the left-right direction. it can. Furthermore, the aspect ratio, which is the ratio of the major axis to the minor axis of the plane ellipse, is adjusted to the elliptical aspect ratio of the hit point distribution of a general player, and is substantially matched with the inertial resistance in the vertical direction, so that the horizontal direction in the horizontal direction is It is possible to suppress not only the fluctuation of the blur but also the fluctuation of the flight distance in the direction of the flying ball.

Therefore, as the count increases, the angle of the major axis direction 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.

[0049]

Next, specific examples of the present invention will be described. That is, as shown in FIG. 8 and FIG.
A recess 2A is formed in the back face portion 2
A back cavity type iron club head 1 in which a peripheral weight portion 3 is formed on the peripheral edge of A, wherein a weight addition portion 5B is formed at an upper end 5A of the toe of the peripheral weight portion 3, and The iron club head 1 is characterized in that a lower weight adding portion 6A having an increased height from the center 6B on the sole portion 6 side to the heel portion 8 is formed.

As shown in FIGS. 10 and 11, the weight adding portion 5B and / or the lower weight adding portion 6 of the toe upper end portion 5A formed on the peripheral weight portion 3 of the back face portion 2.
An iron club head 1 characterized in that a weight member 7 having a higher specific gravity than the metal constituting the head main body 1A is mounted on one or both of the head members A.

Since the present invention has the above-mentioned constitutional requirements, the upper end 5A of the toe is made thicker and the height of the cavity portion below the heel is increased so that the weight is arranged.

An iron club head in which a weight member 7 having a higher specific gravity than the head body material is provided on the heel portion 8 side of the sole portion 6 so as to place the weight at a more desirable portion.

As another embodiment of the present invention, the head main body 1A is made of S35C soft iron, the toe upper end 5B is provided with a triangular thick portion having a thickness of 3 mm, and further has a cavity back. Although the thickness is 3 mm, its height is 5 mm on the heel side and 3 mm on the center and
mm, and a weight member made of a tungsten alloy having a higher specific gravity than the head body is provided on the heel side of the sole portion.
g Press-fit.

As a result, the weight is placed above the toe and below the heel, and the angle formed by the major axis of the plane ellipse with respect to the line of intersection between the cut surface and the ground increases. Decrease.

Incidentally, iron, stainless steel, aluminum, titanium, magnesium, tungsten, copper, nickel, zirconium, cobalt, manganese, zinc, silicon, tin, which are materials commonly used for making a club head, are generally used. Chrome, FRP, synthetic resin,
Ceramics, rubber and the like can be mentioned, and they can be manufactured from a single material thereof, or can be manufactured by combining three or more of these materials. As a manufacturing method, a precision casting method can be used because the cost is low and the dimensional accuracy is high. Others
The head body can also be manufactured by die casting, pressing or forging. On the other hand, each part is manufactured by pressing, forging, precision casting, metal injection, die casting, cutting, powder metallurgy, etc., and they are joined by welding, bonding, press fitting, fitting, pressing, screwing, brazing, etc. A method of fabricating the club head by bonding or bonding is also possible.

FIGS. 12 and 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 were as follows. The golf robot set the speed of the iron club head to 34.5 m / sec, and set the hitting point from the sweet spot as shown in FIG. This is the result of hitting the toe tip, toe above, toe below, heel above, heel below, heel base, center above and below the center respectively. Table 1 shows the specifications of the product of the present invention and the conventional product.

[0058]

[Table 1] On the other hand, the club head shown in FIG. 13 has the same weight (248 g) as the club head shown in FIG. 12, but its plane ellipse has an aspect ratio of 2.3, and the angle in the major axis direction is the intersection between the cut surface and the ground. The angle made with respect to the line is 2 ° downward, and the center of the hit point is 20 mm. From the results of the flight distance measurement test performed by the robot in FIG. 13, the variation between the left and right of the club head in FIG.
In contrast to 0 m, the variation of the club head in FIG. 12 in which the ellipse is matched to the distribution of the hit points of a general player is about 8 m, and the variation of 20% can be reduced.

On the other hand, the variation in the direction of the trajectory is about 15 m for the club head of FIG. 13 and about 8 m for the club head of FIG. 12, indicating a 47% reduction in variation.

FIG. 1 shows a comparison of the average flight distance.
The club head of No. 3 is 154 m, whereas the club head of FIG. 12 is 159 m, and the flying distance is increased by about 5 m.

FIG. 12 and FIG. 13 show the average values when hitting the ball twice, respectively.

The results of the impact on the upper end of the tow clearly show that there is a difference in rotational performance. That is, FIG.
In the case of the club head shown in FIG. 12, the flight distance in the direction of the flying ball due to the impact on the upper end of the toe is remarkable, and the ball is falling to the right as compared with the average lateral displacement. In this case, the flight distance is less reduced due to the impact on the upper end of the toe, and the side running is also reduced. This means that the club head of FIG. 12 is suppressed in rotation of the head as compared with the club head of FIG. 13, and it can be seen that the head rotation performance is excellent.

[0063]

Since the present invention is an iron club head having the above-described configuration, an inertia ellipsoid centered on the center of gravity of the club head passes through the center of gravity of the club head and is virtually formed on a plane parallel to the loft angle. By matching the plane ellipse when cut to almost the distribution of hitting points of a general player, the rotation of the head at the time of an impact collision when a golf ball is impacted is suppressed, the directionality at the time of hitting is improved, and An iron club head capable of exhibiting an effect of increasing a flight distance can be supplied.

[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 an embodiment of an iron club head according to the present invention.

FIG. 11 is a perspective view showing an embodiment of an iron club head according to the present invention.

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.

FIG. 14 is an explanatory view showing a hitting position of the iron club head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Iron club head 1A Head main body 2 Back face part 2A recess 3 Peripheral weight part 3A recess 4 Face part 5 Toe part 5A Toe upper end part 5B Weight addition part 6 Sole part 6A Lower weight addition part 6B Central part 7 Weight member 8 Heel part 9 Sole part C Sweet spot T ・ M Toe tip part TU U toe upper part TD Toe lower part H ・ U Heel upper part H ・ D Heel lower part H ・ M Heel base part C ・ U Center upper part C ・ D Center lower part 20 Golf ball 30 Inertia ellipsoid F Impact force MP Hitting position FH Horizontal component FP Vertical component SS Sweet spot

Continuation of front page (72) Inventor Hiroshi Nagao 1-12-35 Minami Kohoku, Suminoe-ku, Osaka City, Osaka Prefecture F-term (reference) 2C002 AA03 CH02 CH03 LL01 MM04 MM07

Claims (2)

[Claims] 1. A back cavity type iron club head in which a concave portion is formed in a back face portion of a head body and a peripheral weight portion is formed on a peripheral edge of the concave portion, wherein a weight is provided on an upper end of a toe of the peripheral edge portion. An iron club head, wherein an additional portion is formed, and a lower weight additional portion is formed in which a height of a portion from a central portion on a sole portion side of the peripheral edge portion to a heel portion is increased. 2. A specific gravity greater than a metal constituting a head main body at one or both of a weight adding portion and / or a lower weight adding portion at an upper end portion of a toe formed at a peripheral weight portion of the back face portion. The iron club head according to claim 1, wherein a weight member is mounted.