Games using tangible projectile – Golf – Club or club support
Reexamination Certificate
1999-09-23
2001-03-20
Passaniti, Sebastiano (Department: 3711)
Games using tangible projectile
Golf
Club or club support
C473S350000
Reexamination Certificate
active
06203449
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a golf club head and, more particularly, to a metallic hollow golf club head which is generally called as a metal wood.
2. Description of the Related Art
Recently, a large-sized metallic hollow golf club head has been proposed in order to attain a large moment of inertia and a low center of gravity. In a case of so called wood-type golf club head, it is said that an appropriate weight of the golf club head is approximately 200 g for an average golf player. Therefore, it is required to enlarge a golf club head within the aforementioned weight limitations.
A proposal on this kind of conventional golf club head has been made by Japanese Patent Laid-open Publication No. Hei 9-192273. In this golf club head, in order to enlarge the golf club head without changing the weight, the central area of the face including a sweet spot, is formed to have a thickness enduring the impact caused when hitting a ball, and the peripheral area around the central area is formed to have a thickness thinner than that of the central area. This enhances a spring performance of the face as a whole.
Another proposal has been made by Japanese Patent Laid-open Publication No. Hei 9-308713. According to this proposal, in order to provide a large-sized golf club head with a sufficient strength, a plurality of ridges are provided on a rear surface of the face vertically and/or horizontally.
In the meantime, enlarging the size of the golf club head and thinning the thickness of the face remarkably enhances the repulsion force, thereby enabling a longer carry due to so-called spring effects of the face. Therefore, many golf players prefer to use this kind of golf club.
On the other hand, there is a tendency that the player's score is greatly influenced by the selection of the golf club rather than the practice or technique of the player. Accordingly, the U.S.G.A. (United States Golf Association) is now trying to revise the golf rules so as to clearly regulate the spring effects of a golf club head.
In detail, the U.S.G.A is now trying to eliminate the unclear conventional definition on an “excess spring effect” by defining a concrete measuring method for measuring a repulsion coefficient of a spring effect, or a concrete devise for measuring the same.
In view of the above-mentioned trend, the metallic golf club head proposed by Japanese Patent Laid-open Publication No. Hei 9-192273 may become an improper golf club head in view of the revised golf rules because of the excessive spring effect.
On the other hand, the metallic golf club head proposed by Japanese Patent Laid-open Publication No. Hei 9-308713 may have a higher center of gravity because of the plurality of ridges formed on the whole area of the face. This contradicts the requirement for lowering the center of gravity of the golf club head.
SUMMARY OF THE INVENTION
The present invention was conceived to overcome the above-described problems. It is an object of the present invention to provide a metallic golf club head which is capable of enlarging the head size and restraining the spring effect while keeping the mechanical strength of the face.
According to one aspect of the present invention, a metallic golf club head includes a face having a plurality of scoring lines formed horizontally on a front surface of the face, and a plurality of reinforcing ridges formed on a rear surface of the face within a sweet area thereof. The plurality of ridges are formed along the scoring lines.
It is preferable that each reinforcing ridge is positioned right behind the corresponding scoring line so as to compensate the partially decreased thickness of the face caused by forming the scoring line.
Although a plurality of reinforcing ridges may be formed along all of the scoring lines, if the face is divided into three zones, i.e., an upper zone, a middle zone and a lower zone, the reinforcing ridges are not always required to be formed in the lower zone.
It is preferable that the width of each reinforcing ridge falls within the range of from 1.0 to 3.5 mm, and the height thereof falls within the range of from 0.8 to 2.0 mm, because of the following reasons: if the width or height of the reinforcing ridge is lower than the respective lower limit, the reinforcing effect by the reinforcing ridge decreases. On the other hand, if the width or height exceeds the respective upper limit, the weight of the golf club head increases. More effective size of the reinforcing ridge may be decided within the aforementioned range, considering the materials and the thickness of the face, the depth and width of the scoring line and the intervals of the adjacent scoring lines, and the like.
It is preferable that the thickness of the face falls within the range of from 2.5 to 3.5 mm, and the thickness of the other portion, i.e., the crown, the sole, the toe and the neck, falls within the range of from 0.5 to 1.5 mm.
In this specification, the word “titanium” denotes a titanium and its alloy including a titanium as a main ingredient and an aluminum, a vanadium, or the like, as an additive. The word “sweet area” denotes an area including a center portion of the face and a portion around thereof by which 90% or more of the maximum carry is obtained.
REFERENCES:
patent: 572436 (1896-12-01), Mills
patent: 4511145 (1985-04-01), Schmidt
patent: 4635941 (1987-01-01), Yoneyama
patent: 5090702 (1992-02-01), Viste
patent: 5377985 (1995-01-01), Ohnishi
patent: 5533729 (1996-07-01), Leu
patent: 5611742 (1997-03-01), Kobayashi
patent: 5665013 (1997-09-01), Kobayashi
patent: 5676605 (1997-10-01), Kobayashi
patent: 5711722 (1998-01-01), Miyajima
patent: 5735755 (1998-04-01), Kobayashi
patent: 5908357 (1999-06-01), Hsieh
patent: 9-192273 (1997-07-01), None
patent: 9-308713 (1997-12-01), None
Armstrong Westerman Hattori McLeland & Naughton LLP
Passaniti Sebastiano
Royal Collection Incorporated
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