JP3919846B2 - Iron golf club head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an iron golf club head, and in particular, a sole is formed from a lower end of a face surface that hits a ball to a back surface side, and is recessed in a central portion surrounded by ribs provided around the back surface. The present invention relates to an iron golf club head called a so-called cavity back.
[0002]
[Prior art]
The head of an iron golf club is called a muscle back, a plain back, a cavity back, or the like depending on the shape of the back surface. Since the position of the center of gravity can be moved according to the degree of fleshing on the back surface of the head, various designs and designs are applied to this back surface. A muscle back is a muscle back that has a bulge like muscle, a plain back is the one with the same thickness, and a cavity back is the one from which the meat in the center is shaved off. In an iron golf club head, it has been attempted to increase the moment of inertia about the vertical axis and the horizontal axis of the head in order to improve the lateral and vertical stability of the hit ball, thereby expanding the sweet area. Therefore, as a representative example of various measures taken for that purpose, on the back surface of the head, the meat is shaved off leaving the minimum necessary thickness between the head surface and the shaved meat on the periphery. By adding, a structure in which a wide depression (cavity) and a thick peripheral edge (rib) surrounding the depression are formed on the back surface, that is, a cavity back structure has been widely adopted. With a structure where the thickness of the center part of the head is reduced and the surrounding area is heavy, that is, the weight is distributed around the head, the entire head can be enlarged, the sweet area can be enlarged, there is less blur due to miss shots, and less power loss. Therefore, mistakes are less likely to appear in both direction and distance.
[0003]
[Problems to be solved by the invention]
In the peripheral weight distribution by the cavity, if the top blade is made thick, that is, if the upper part of the head is thick and the bottom part is thick, the center of gravity becomes high, the ball is hard to rise and the long iron is hard to hit. . For this reason, the sole side has a maximum thickness, and the thickness is gradually reduced from the sole side to the toe portion, the heel portion, and the top blade. The wall thickness at the position of the top blade is one third or less of the wall thickness on the sole side. Such a head is easy to raise the ball and is excellent in the direction stability of the hit ball, but the vibration caused by the impact at the time of swing increases near the thin top blade, which makes the player's hand uncomfortable. There was a problem of giving. In order to solve such a problem, an attempt has been made to arrange a thermosetting resin such as CFRP or a thermoplastic resin along the peripheral edge of the cavity on the top blade side, but it has not been sufficiently effective. Further, in the case where the thickness between the face surface and the bottom of the recess, that is, the thickness of the impact portion is made as thin as possible, there is a drawback that the ball feels good but the hit feeling is poor. The unpleasant sensation based on the vibration is a problem that occurs not only in the cavity back but also in other types when hit with the core removed.
[0004]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an iron golf club head that is not easily transmitted to the hand at the time of impact and has an excellent hit feeling.
[0005]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention forms a recess in the center part of the back surface on the back side of the face surface that hits the ball, surrounded by ribs, and becomes the bottom of the recess on the back side of the face surface. A plate-like body of a magnesium-based alloy having a magnesium amount exceeding 50% is provided, and an insulating layer made of an electrical insulator is provided on the entire bottom between the plate-like body and the bottom of the recess, and the insulating layer is made of epoxy resin or It consists of glass fiber reinforced resin .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the drawings.
[0007]
In the embodiment shown in FIG. 1, a sole 3 is formed from the lower end of the face surface 1 that hits the ball to the back surface 2 side, and is surrounded by ribs 4 provided around the back surface 2. A recess 5 is formed in the bottom. A hosel 6 for mounting a shaft (not shown) is provided on the head. Further, a plate-like body 7 of a magnesium base alloy is provided on the back side of the face surface 1 at a location that becomes the bottom 5A of the recess 5.
[0008]
FIG. 2 is a longitudinal sectional view of FIG. 1, and in this embodiment, an insulating layer 8 is provided between the back side of the face surface 1 and the plate-like body 7. In this embodiment, the recess 5 is shallow at the top position, the depth is gradually increased in the direction of the sole 3, and is deepest at a position closest to the sole 3. The rising height of the rib 4 is also increased according to the depth of the recess 5 depending on the position. Although the epoxy resin insulating layer 8 is provided on the entire bottom 5A of the recess 5, an insulating material having a predetermined strength, such as a glass fiber reinforced resin, can be used as the insulating layer 8. The plate-like body 7 was a JIS symbol MC2 magnesium base alloy having a thickness of about 1 mm. In the drawing, the plate-like body 7 having the same thickness from the top blade side to the sole 3 side is used. However, since the specific gravity of the magnesium base alloy is as small as about 2.0, the depression 5 is filled to fill the depression 5. The position where the depth of 5 is shallow can be made thin, and the position where the depth is deep can be made thick. Further, various materials such as stainless steel, soft iron, titanium and alloys thereof, copper alloys, aluminum and alloys thereof can be used for the head itself. Further, a so-called composite head in which only the portion of the head that impacts the ball is formed of a separate material may be used.
The plate-like body 7 can be provided not only in the cavity back type shown in FIGS. 1 and 2 but also in other types, in the entire back surface or in a central region other than the peripheral portion of the back surface. It is also possible to cover the plate-like body thus provided with a resin layer.
[0009]
As the plate 7 of the magnesium base alloy, the surface of the magnesium base alloy is washed by blasting or the like, followed by dichromate 0.2 to 0.4 mol / liter, nitric acid (60%) 7 to 15 ml / liter. It is desirable to form a protective coating on the surface by dipping in a treatment solution having a composition of primary phosphate 0.5 to 0.7 mol / liter and selenious acid 10 to 20 g / liter. A more preferable composition of the treatment liquid is as follows.
Sodium dichromate 65-80 g / liter nitric acid (60%) 7-15 ml / liter primary sodium phosphate 65-80 g / liter selenious acid 10-20 g / liter After being immersed in such a treatment solution, it is washed with water and dried. A protective coating was formed on the surface of the alloy. As a more preferable processing condition, it is immersed in a processing solution heated to 80 to 90 ° C. for 2 to 8 minutes. Here, as a comparative example, an alloy called “AZ92” in a magnesium base alloy is subjected to pretreatment before blasting, and then hydrofluoric acid (46%) at a liquid temperature of 20 to 30 ° C. in 248 ml / liter for 30 seconds to 5 seconds. Immerse for 5 minutes, wash with water, then immerse in 50 g / liter of acidic sodium fluoride (or acidic potassium fluoride or acidic ammonium fluoride) with a liquid temperature of 20-30 ° C. for 5 minutes and wash with water, 120-130 g of sodium dichromate / Litter and calcium fluoride (or magnesium fluoride) 50g / Litter solution boiled for 30 minutes, washed with water, finally immersed in warm water, dried and prepared for corrosion protection did. As a result of observing the plate-like body 7 of the magnesium-based alloy and the comparative example with the above-described protective coating by damaging with a wire brush, the comparative example remained exposed when the magnesium-based alloy was exposed, but formed a protective coating. When the magnesium base alloy was exposed, a local battery was formed between the magnesium and selenium, and selenium oxide was deposited, so that a protective coating was formed on the surface of the magnesium base alloy again. In addition, as a result of observing the corrosion resistance by the salt spray test method of JIS Z 2371, it was found that the magnesium base alloy on which the protective film was formed had excellent corrosion resistance.
[0010]
The magnesium-based alloy forming the plate-like body 7 refers to an alloy having a magnesium amount exceeding 50%. In addition to magnesium, other metal components such as Al, Zn, Mn, Zr, Si, Cu, and Ni may be included. As a magnesium-based alloy that can be suitably used, MC2 and MC3 can be suitably used as JIS symbols. By providing the insulating layer 8 as described above between the bottom 5A of the recess 5 and the plate-like body 7, even if the protective film is not formed, corrosion of the plate-like body 7 is well prevented. be able to.
[0011]
An impact impact test was conducted using a golf club having the example head shown in FIGS. 1 and 2 and a golf club having a head in which nothing is provided in the recess 5 as a comparative example. As the material of the head, soft iron (S20C) was used in both the examples and the comparative examples, and a No. 3 iron was used as the club used. The hosel 6 was provided with a steel shaft. The plate-like body 7 in the embodiment is a magnesium based alloy of MC2 with JIS symbol, having a thickness of 1 mm, and the insulating layer 8 is an epoxy resin. The result of the example of this impact test was as shown in the graph of FIG. 3, and the comparative example was as shown in the graph of FIG. In the example, it can be seen that the amplitude of vibration is very small as shown in the graph of FIG.
[0012]
When the plate-like body 7 is provided on the bottom 5A directly or via the insulating layer 6, means such as fitting or bonding to the inner peripheral surface of the rib 4 and fastening with screws or the like can be employed. In addition, the size of the plate-like body 7 is preferably a size that covers the entire bottom 5A, but may be a size that is more than half of the area of the bottom 5A and is behind the impact portion.
[0013]
【The invention's effect】
As described above, according to the present invention, the back surface on the back side of the face surface that hits the ball is surrounded by ribs so that a recess is formed in the center, and the bottom of the recess is formed on the back side of the face surface. A plate-like body of a magnesium-based alloy having a magnesium amount exceeding 50% is provided, and an insulating layer made of an electrical insulator is provided on the entire bottom between the plate-like body and the bottom of the recess, and the insulating layer is made of epoxy resin or Since it is made of glass fiber reinforced resin , vibrations are not easily transmitted to the hand, and the feel is excellent. In addition, by providing an insulating layer between the back side of the face surface and the plate-like body, it is possible to further prevent transmission of vibration and obtain a soft feel. Since an insulating material having a predetermined strength is used as the insulating layer, corrosion prevention of the magnesium-based alloy can be achieved. A magnesium-based alloy with a protective coating is also effective in preventing corrosion.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a preferred embodiment of the present invention.
FIG. 2 is a longitudinal sectional view.
FIG. 3 is a graph showing the impact test results of the examples.
FIG. 4 is a graph showing an impact test result of a comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Face surface 2 Back surface 3 Sole 4 Rib 5 Indentation 5A Indentation bottom 7 Plate-shaped body

Claims (4)

The back surface on the back side of the face surface that hits the ball is surrounded by ribs to form a recess in the center,
A plate-like body of a magnesium-based alloy having a magnetism amount exceeding 50% is provided at the bottom of the recess on the back side of the face surface,
An insulating layer made of an electrical insulator is provided on the entire bottom between the plate-like body and the bottom of the depression ,
An iron golf club head, wherein the insulating layer is made of epoxy resin or glass fiber reinforced resin .   After cleaning the skin of the magnesium-based alloy forming the plate-like body, dichromate 0.2-0.4 mol / liter, nitric acid (60%) 7-15 ml / liter, primary phosphate 0.5 The iron golf club head according to claim 1, wherein a protective film is formed on the surface by dipping in a treatment liquid having a composition of -0.7 mol / liter and selenious acid of 10-20 g / liter. Iron golf club head according to any one of claims 1 or 2, characterized in that the thickness of the plate-like body and 1 mm. The iron golf club head according to any one of claims 1 to 3 , wherein a resin layer is coated on the plate-like body.

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