Games using tangible projectile – Golf – Club or club support
Reexamination Certificate
1999-12-13
2001-11-27
Passaniti, Sebastiano (Department: 3711)
Games using tangible projectile
Golf
Club or club support
C473S331000, C473S345000
Reexamination Certificate
active
06322459
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a golf club head having a hollow structure. More specifically, the invention relates to a golf club head capable of setting an optional spin characteristic of a ball without giving any substantial effects on a center of gravity or a total weight, and thereby satisfying a request made by a golfer.
The golf club head generates rotation around its center of gravity when it hits a ball by a portion shifted from a sweet spot, and then gives a spin to the ball. This spin generating mechanism is generally called a gear effect. For example, in a conventional head structure, because of the gear effect, the quantity of backspin is reduced more for a ball hit by a head upper portion compared with a ball hit by a center portion. The quantity of backspin is increased more for a ball hit by a head lower portion compared with a ball hit by a center portion. In the case of a ball hit by a head toe portion, hook rotation (left rotation) is generated and, in the case of a ball hit by a heel portion, slice rotation (right rotation) is generated. In addition, it is generally known that the gear effect is increased as a thickness of a face portion is thinner, and the gear effect is reduced as a thickness thereof is thicker.
Thus, to control a spin characteristic of a ball, efforts have been made to reduce the gear effect by changing the thickness of the face portion to change its rigidity. However, the changed thickness of the face portion resulted not only in the change in the rigidity of the face portion but also in the change in the center of gravity or total weight of the golf club head. Moreover, the changed thickness of the face portion resulted in the complexity of designing a core used for molding. Consequently, thickness accuracy was difficult to obtain, and a molten metal flow failure and other manufacturing difficulties easily occurred. The changed thickness also caused inconveniences such as a deteriorated hitting sound as a golf club head.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a golf club head capable of setting an optional spin characteristic of a ball without giving any substantial effects on a center of gravity or a total weight.
In order to achieve the above object, a golf club head of the present invention comprises: a hollow structure composed of a face portion constituting a ball hitting face, a crown portion and a sole portion each provided successively from the face portion; and a plurality of grooves provided in the face portion. Depths of the grooves are gradually changed in accordance with a position of the face portion. More specifically, depths of the grooves are set larger in a position for reducing rigidity of the face portion more.
As described above, the plurality of grooves are provided in the face portion of the golf club head, and depths of the grooves are gradually changed in accordance with a position of the face portion. Accordingly, only rigidity of the face can be changed while keeping constant a thickness of the face portion or without changing a thickness of the same. Thus, a ball spin characteristic can be optionally set without any substantial effects given on a center of gravity or a total weight. With this constitution, various requests made by golfers can be satisfied without any great designing changes for the golf club head.
Furthermore, since it is not necessary to change a thickness of the face portion, designing of a core used during molding can be simplified, and thickness accuracy can be increased. Accordingly, inconveniences such as a molten metal flow failure or the like can be prevented. Moreover, since it is not necessary to change a thickness of the face portion, good hitting sound as a golf club head can be maintained.
Regarding the plurality of grooves, score lines provided in an outer surface of the face portion can be utilized. In particular, according to the present invention, since depths of the grooves are changed in accordance with a position of the face portion, rigidity of the face portion can be adjusted without changing the appearance of the score lines at all. But these grooves may be provided in an inner surface of the face portion.
REFERENCES:
patent: 4508349 (1985-04-01), Gebauer
patent: 4550914 (1985-11-01), McCallister
patent: 4792140 (1988-12-01), Yamaguchi
patent: 5090702 (1992-02-01), Viste
patent: 5591092 (1997-01-01), Gilbert
patent: 5601501 (1997-02-01), Kobayashi
patent: 5611742 (1997-03-01), Kobayashi
patent: 5676605 (1997-10-01), Kobayashi
patent: 5688186 (1997-11-01), Michaels
patent: 5711722 (1998-01-01), Miyajima
patent: 5735755 (1998-04-01), Kobayashi
patent: 5755626 (1998-05-01), Shira
patent: 5762566 (1998-06-01), King
patent: 5766087 (1998-06-01), Kawamatsu
Miyamoto Masahiko
Nishimura Toshinori
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Passaniti Sebastiano
The Yokohama Rubber Co. Ltd.
LandOfFree
Golf club head does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Golf club head, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Golf club head will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2613661