JP2007151851A - Iron golf club head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To disclose the reference for the combination of different metals in obtaining a golf club head having the depth of the center of gravity enough to raise a ball. <P>SOLUTION: As regards an iron golf club head comprising two or more kinds of different metals, the distance between the center of gravity at the right angle to the face between a portion made of a meal occupying the largest volume out of the metals and other metals is 1.7 mm as the minimum for the number 3, 1.8 mm for the number 5, 1.4 mm for the number 7 and 1.5 mm for the number 9. The distance satisfies the following expressions in the order of the number 3, the number 5, the number 7 and the number 9: The minimum value <L×W2/(W1+W2)-H1, wherein H1=L×k×W2/(W1+k×W2), L is the distance between the centers of gravity at the right angle to face between metal of the body and other metals, W1 is the weight of the body, W2 is the total weight of the other metals, H1 is a correction item for position of the center of gravity of the whole of original head (without notch for filling), namely, distance between the center of gravity of body before the same metals are combined and that after the combination, k=r1/r2 (r1 is the specific gravity of the body metal and r2 is the specific gravity of the filled metal). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an iron golf club head, and more particularly to an iron golf club head formed of two or more different kinds of metals.

  The depth from the face to the center of gravity of the iron golf club head (perpendicular to the face) is called the center of gravity depth. It is known that the ball easily rises when the center of gravity depth (unit: mm) becomes deeper. If the head has the same loft angle, the greater the depth of the center of gravity, the easier the ball will rise and the easier it will be to hit.

  Many golfers feel that the iron on the cavity back is easier to hit than the iron on the muscle back when comparing the conventional iron of the muscle back with the same loft angle and the iron of the cavity back. As a result of measuring the depth of the center of gravity of 6 types of commercially available muscle backs 3 to 9 iron sets and 9 types of similar iron sets of cavity backs, the graph shown in FIG. 3 was obtained. As is apparent from this graph, the iron of the cavity back has a deeper center of gravity than the iron of the muscle back, so that the ball is easy to rise and feels easy to hit.

  From the graph of FIG. 3, the difference between the center back depth of the muscle back iron and the cavity back iron was quantitatively grasped, and the results shown in the following Table 1 were obtained.

In order to increase the center of gravity depth and make it easier to raise the ball, it is more advantageous to form the head from a different metal than from the same material, so the face side of the head is formed from a material with a low specific gravity, It has been proposed to form the rear part of the head with a material having a large specific gravity. And the technique of firmly integrating dissimilar metals has also been developed (see Patent Document 1).
JP-A-6-335541 (2nd page, FIG. 1)

  A hybrid structure in which the head is made of a different metal can increase the depth of the center of gravity and improve the performance of the head. However, the advantages of having a hybrid structure have been fully considered and few have been designed, and even with the hybrid structure head disclosed in Patent Document 1, the face member is firmly attached to the surface of the cavity-backed weight member. In many cases, there is no difference between the cavity back iron formed of the same material and the depth of the center of gravity.

  It goes without saying that a head having a hybrid structure using a combination of different metals may have a greater degree of design freedom than a single metal head. However, the effect varies greatly depending on how it is used. It is an object of the present invention to disclose a dissimilar metal combination criterion that enables an efficient hybrid structure design for obtaining a golf club head having a depth of center of gravity that facilitates the ball to rise.

The present invention relates to an iron golf club head made of two or more kinds of different metals, the main body being a portion formed from the metal occupying the largest volume, and the center of gravity perpendicular to the face of the main body and the other metal. The distance between every other number is 1.7mm for No.3, 1.8mm for No.5, 1.4mm for No.7, 1.5mm for No.9 with the minimum value of No.3, No.5 , 7 and 9 in order, the following expressions are satisfied.
Minimum value <L × W2 / (W1 + W2) −H1
H1 = L × k × W2 / (W1 + k × W2)
L: Distance between the center of gravity in the direction perpendicular to the face of the main body and the other metal W1: Weight of the main body W2: Total weight of the other metal H1: Position of the center of gravity of the original head (no filling notch) Correction term, ie
The distance between the center of gravity of the main body and the center of gravity after combining the same metal k = r1 / r2 r1: Specific gravity of the main body metal r2: Specific gravity of the filling metal

  According to the present invention, it is not the ideal effect of simply forming a hybrid structure head made of dissimilar metals and making the depth of the center of gravity deeper than that made of the same metal, but to the extent that the golfer really feels easy to hit It is possible to provide a head having a hybrid structure in which the depth of the center of gravity can be designed.

  The feeling of how easy it is to lift and hit the ball varies depending on the golfer. For example, if there is a golfer who feels easy to hit even with a small difference (1.3 mm difference), such as a muscle back No. 5 with a center of gravity depth of 2.6 mm and a cavity back iron No. 5 with a diameter of 3.9 mm, the depth of center of gravity is 1 Some golfers do not feel easy to hit unless the difference is as large as a 5.8mm muscle back # 5 and a 5.7mm cavity back iron # 5. This is summarized in Table 2 for each count.

  As described above, the inventor sets the minimum value of the limit feeling the difference as the difference between the lower limit centroid depth of the cavity back iron and the upper limit centroid depth of the same number of muscle back irons, as a more preferable difference of the limit feeling difference. In order to realize the difference in the performance of the club head that can be experienced by the center of gravity depth as the difference between the center of gravity depth of the upper limit of the cavity iron and the center of gravity lower limit of the muscle back iron of the same number, It was necessary to achieve this difference. More preferably, it is necessary to achieve a difference in the center-of-gravity depth that is equal to or greater than the above preferred value.

  On the other hand, the limit of the difference in the center of gravity depth is limited by the physical shape of the iron. That is, if the distance between the plane parallel to the face surface and the surface on the back side of the head is the head thickness, it is impossible to set the center of gravity beyond that. There is a head thickness of about 40 mm for a hollow iron, which is considered the limit.

Based on the above-mentioned consideration results, as shown in FIGS. 1 and 2, the largest volume among the iron golf club heads 1 made of two or more different metals is used as a reference for designing the head of the hybrid structure. The portion formed from the occupied metal is the main body 1A, and the distance between the centers of gravity in the direction perpendicular to the face 2 between the main body 1A and the other metal 1B is every other number of counts.
Minimum value (shown in Table 2) <L × W2 / (W1 + W2) −H1
It is assumed that the iron head having a hybrid structure is an efficient hybrid design.
H1 = L × k × W2 / (W1 + k × W2)
L: Distance between the center of gravity in the direction perpendicular to the face of the main body and the other metal W1: Weight of the main body W2: Total weight of the other metal H1: Position of the center of gravity of the original head (no filling notch) Correction term, ie
The distance between the center of gravity of the main body and the center of gravity after combining the same metal k = r1 / r2 r1: Specific gravity of the main body metal r2: Specific gravity of the filling metal

Even more preferably, for every second count,
Maximum value (shown in Table 2) <L × W2 / (W1 + W2) −H1
It is assumed that the iron head having a hybrid structure is an efficient hybrid design.
H1 = L × k × W2 / (W1 + k × W2)
L: Distance between the center of gravity in the direction perpendicular to the face of the main body and the other metal W1: Weight of the main body W2: Total weight of the other metal H1: Position of the center of gravity of the original head (no filling notch) Correction term, ie
The distance between the center of gravity of the main body and the center of gravity after combining the same metal k = r1 / r2 r1: Specific gravity of the main body metal r2: Specific gravity of the filling metal

  FIG. 1 shows the center of gravity positions G1 and G2 of the main body 1A and the other filling metal 1B, and FIG. 2 shows a cross section of the head 1 having a hybrid structure in which they are combined. Further, the distance between the centers of gravity of the main body 1A and the filling metal 1B orthogonal to the face 2 is shown as L, the weight of the main body 1A is W1, and the weight of the filling metal 1B is W2. The center of gravity of the head 1 in FIG. A distance between the center of gravity G and the center of gravity G1 of the main body 1A is indicated by H. The above-mentioned “H1” means that when the main body 1A and the filling metal 1B are made of the same metal having the same specific gravity, for example, soft iron, the center of gravity of the head when the main body 1A and the filling metal 1B are combined and the center of gravity of the main body 1A before the combination. And called the “correction term for the center of gravity of the entire head (without the filling notch)”. “H” is the distance between the center of gravity G1 of the main body 1A when the dissimilar metals are combined and the center of gravity G after combining.

When the main body 1A is formed of soft iron (specific gravity 7.8 g / cm ^2), the filler metal 1B formed with tungsten alloy (specific gravity 18 g / cm ^2), to form, for example, 5 iron, the total volume of the head 1 By providing the filling metal 1B so as to occupy 20%, the value of “L × W2 / (W1 + W2) −H” can be made larger than the minimum value of 1.3 mm (see Table 2) of the No. 5 iron, It became a 5 iron with a depth of center of gravity that was easy to hit.

  Assuming that the distance L between the centers of gravity in FIG. 2 is 10 mm, the center of gravity G of the head 1 is a position deeper than the center of gravity G1 of the main body 1A by H (mm). Since the distance of H is H = L × W2 / (W1 + W2), assuming that the head weight of the No. 5 iron is 315 g, the main body 1A (soft iron) is 200 g, the filling metal 1B (tungsten) is 115 g, and H = 3.65 mm. Note that “H1” has a head weight of 250 g (main body 1A = 200 g, filled metal 1B = 50 g), and when both metals 1A and 1B are made of soft iron, H1 = 2 mm. If the head weight of 315 g of the fifth iron of this hybrid structure is too heavy, as shown in FIG. 3, a main body 1A having a hollow 4 is formed, and W1 = 135 g, and the total head weight is 250 g. (W2 = 115 g).

  Although an example in which the main body 1A is made of soft iron has been described, it can be formed of a low specific gravity metal such as titanium, an alloy thereof, or an aluminum alloy. By forming the main body 1A of a low specific gravity metal, the face 2 side is lightened. It is possible to make the center of gravity deeper.

  In the above-described embodiment, every other count (# 3, # 5, # 7, # 9) has been described, but # 4, # 6, and # 8 are designed according to the adjacent counts.

Sectional drawing before assembling and integrating two types of dissimilar metals. Cross-sectional view of a hybrid structure head. FIG. 6 is a cross-sectional view of a head showing another embodiment. The graph which shows the gravity center depth of a commercially available golf club.

Explanation of symbols

1 Head 1A Body 1B Metal 3 Notch W1 Body weight W2 Metal weight

Claims (2)

Regarding the iron golf club head composed of two or more kinds of different metals, the portion formed from the metal occupying the largest volume among them is the main body, and the distance between the center of gravity in the direction perpendicular to the face of the main body and the other metal is For every other count, No. 3 is 1.7 mm, No. 5 is 1.8 mm, No. 7 is 1.4 mm, No. 9 is 1.5 mm and the minimum value is No. 3, No. 5, No. 7, An iron golf club head characterized by satisfying the following formulas in the order of No. 9.
Minimum value <L × W2 / (W1 + W2) −H1
H1 = L × k × W2 / (W1 + k × W2)
L: Distance between the center of gravity in the direction perpendicular to the face of the main body and the other metal W1: Weight of the main body W2: Total weight of the other metal H1: Position of the center of gravity of the original head (no filling notch) Correction term, ie
The distance between the center of gravity of the main body and the center of gravity after combining the same metal k = r1 / r2 r1: Specific gravity of the main body metal r2: Specific gravity of the filling metal The distance between the centers of gravity is 3.7 mm for No. 3, 3.9 mm for No. 5, 4.1 mm for No. 7, and 5.0 mm for No. 9, and the following formulas are satisfied in the order of these numbers. The iron golf club head according to claim 1.
Maximum value <L × k × W2 / (W1 + k × W2) −H1

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