Golf Club Head

Abstract

A golf club head (20) having a center of gravity located relatively forward toward the front wall (30) or striking plate (40) of the golf club head (20), and a relatively high moment of inertia about the Iyy axis through the center of gravity of the golf club head (20) is disclosed. The golf club head (20) preferably has a volume between 300 cubic centimeters and 500 cubic centimeters. The golf club head (20) preferably has a mass between 105 grams and 300 grams. The positioning of the of the center of gravity of the golf club head (20) and the relatively high moment of inertia Iyy through the center of gravity provide for a golf club with greater robustness and better performance.

Description

CROSS REFERENCES TO RELATED APPLICATIONS [0001] The present application is a divisional of U.S. patent application Ser. No. 10 / 250,001, which was filed on May 27, 2003.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable BACKGROUND OF THE INVENTION [0003] 1. Field of the Invention [0004] The present invention relates to a golf club head designed with a forward center of gravity and a relatively high moment of inertia about the Iyy axis through the center of gravity. [0005] 2. Description of the Related Art [0006] As driver golf club heads became larger in volume (>300 cubic centimeters) the moments of inertia of the drivers became larger, which provided greater forgiveness for off-center hits. The conventional method for enlargement of golf club heads was to maximize the spatial distribution of mass in all three orthogonal orientations. Although this approach was effective in increasing the moments of inertia of the golf club heads, it also result...

AI Technical Summary

Benefits of technology

The present invention is a golf club head that has a forward center of gravity and high moments of inertia about the Y and Z axes through the center of gravity. This design provides increased distance and straightness for off-center hits, a more stable feel, and increased spin robustness. By positioning the center of gravity closer to the front wall, the gear effect is reduced, resulting in a more consistent ball flight, improved accuracy, and increased distance.

Problems solved by technology

Although this approach was effective in increasing the moments of inertia of the golf club heads, it also resulted in the center of gravity of the golf club head being positioned substantially rearward from the face center point of the golf club head.

As the center of gravity is positioned rearward from the face, deleterious effects result for shots struck off-center from the sweet spot of the golf club head.

Increased gear effect is the main cause of the deleterious effects.

For heel-ward or toe-ward off-center hits, the increased gear effect can cause increased side-spin, which increases dispersion, reduces distance and reduces robustness.

For off-center hits above the sweet spot, the increased gear effect causes reduced backspin, which can cause an undesirable trajectory having insufficient carry length or time of flight which in turn can result in reduced distance and reduced robustness.

In addition, the same conventional golf club head designs are limited with regard to the maximum face area, both physical and practical limitations.

The physical limitation is due to the golf club head having insufficient mass to both increase the length and width of the golf club head, and also increase the face size without exceeding the upper range of the preferred total golf club head mass.

The practical limitation is that as the face size is increased, hit locations in certain regions around the face perimeter will yield an unsatisfactory ball flight due to the aforementioned deleterious effects which are accentuated for larger faces.

The deleterious effects increase in a non-linear manner as distance from the face center increases so that the incremental face area gained by increasing face size will be subject to the most extreme deleterious effects.

This limits the practical length of the club because probable hit distribution across the surface of the face broadens as the club length increases.

Further, conventional head designs having a center of gravity positioned substantially rearward from the face are subject to significant dynamic loft effects, which can be undesirable.

This is opposite of what is desired as higher head speeds generally require less loft, otherwise excess back spin will be generated, which negatively affects trajectory and performance.

However, the Kajita invention does not address a high moment of inertia about the horizontal axis.

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