Golf club head

Abstract

A golf club having an increased moment of inertia and improved ball-hitting directionality is provided. A metal hollow golf club head comprises: a face portion; a crown portion; and a sole portion, and when the golf club has a lie angle of 60° with its club head volume being within 470 cm3, a moment of inertia about the axial line centered on the plumb line passing through the golf club head center of gravity is 5000 to 6000 g-cm2. In order to increase the moment of inertia, the thickness of the center portion of the crown portion is reduced by chemical etching, and a mass, including the portion of mass reduction, is positioned in the sole portion on the side of the toe portion; moreover, the separation distance from the center of gravity to the mass is increased.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is a Continuation-in-Part of Non Provisional Application No. 11 / 937,868 filed on Nov. 9, 2007, which claims priority to Japanese Application No. 2006-305003, filed on Nov. 10, 2006.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a golf club head with improved ball-hitting directionality, and more specifically, relates to a golf club head having a large moment of inertia and improved stability of direction of a hit ball.[0004]2. Description of the Related Art[0005]Various improvements have been made to golf clubs, to extend flight distances, and to enable stable hitting of the ball. Flight distances directly affect scores, and so through improvements so as to broaden the effective range (“sweet” area) of the striking point on a golf club head (hereafter also simply called a “head”), improvements in the position of the effective area, improvements in the material of the face s...

AI Technical Summary

Benefits of technology

The invention is about a new golf club made of metal that has a larger volume and higher moment of inertia, which makes it easier for the club to hit the ball with precision. This makes it possible for golfers to improve their scores and hit the ball in a more stable manner. The club is also made of metal, which provides durability and a good sound when hitting the ball.

Problems solved by technology

There is a trend toward larger heads, but the masses of the constituent parts of a head adds up, and the swing balance, which is a criterion for ease of swinging of a club, becomes heavy.

As a result, head masses have in the prior art been no greater than approximately 210 g. That is, given the configuration of the prior art, although heads have tended to increase in size the total mass has been limited, and so excess mass to control the position of the center of gravity, or in other words, excess mass to increase the moment of inertia has in the prior art been limited to approximately 10 g, due to the constraint that the total mass should not be increased.

Further, the hosel portion connected to the shaft is positioned on one end of the face portion, and the weight of this portion is also relatively great.

Due to such constraints, it is extremely difficult to increase the weight or other excess mass so as to increase the moment of inertia.

Thus various measures have been taken to extend the flight distance of golf clubs, but at present club performance remains not entirely satisfactory.

While the technologies described above have represented partial improvements, problems remain, and there is still room for improvement.

Metal hollow golf club heads tend to increase in size, as described above, and if the moment of inertia is increased, the volume tends to increase as well; if the volume is increased while making efforts to limit mass, strength-related problems arise; and so there have been limits to the methods employed in the prior art.

When for example using fiber-reinforced resins as described above, not only do strength-related limits appear, but there are the problems of unsatisfactory ball-hitting sounds and resistance to damage.

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