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  Golf clubUSPTO Application #: 20060009302Title: Golf club Abstract: A golf club comprises a shaft and a head, wherein a moment Ix of inertia of the golf club head around a vertical axis passing through the center of gravity of the club head is not less than 3800 (g·sq.cm), and a shaft-torque T (degrees) of the golf club shaft and the moment Ix of inertia satisfy the following condition (1): T=<0.0025×Ix−6.0. (end of abstract)
Agent: Birch Stewart Kolasch & Birch - Falls Church, VA, US Inventor: Hitoshi Oyama USPTO Applicaton #: 20060009302 - Class: 473282000 (USPTO) Related Patent Categories: Games Using Tangible Projectile, Golf, Club Or Club Support The Patent Description & Claims data below is from USPTO Patent Application 20060009302. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] The present invention relates to a golf club and more particularly to a combination of a club head having a specific moment of inertia and a club shaft having a specific shaft-torque. [0002] Heretofore, in improving the directional stability of the struck balls, it has been considered to be effective to increase the moment of inertia of the club head or to change the bending rigidity and twist rigidity of the club shaft as shown in Japanese patent application publication NOS. 7-112041, 8-187308, 9-38254 and 11-76479. These prior arts, however, failed to provide discussion about the relationship between such parameters of the club head and shaft. [0003] In general, in the case of golf clubs targeted at professionals and advanced golfers, the moment Ix of inertia of the head is relatively small, and also the shaft-torque is relatively small. Contrary, in the case of golf clubs targeted at high-handicapped golfers, the moment Ix of inertia and shaft-torque T are relatively large. [0004] AS to golf swing, the professionals and advanced golfers can make a body-led swing, and the swing path or swing circle and ball hitting position are stable. And as the head speed is high, the backspin tends to become excessively increased. Therefore, in the club heads targeted at professionals and advanced golfers, it is desirable that the center of gravity of the club head is relatively low in order to avoid an excessive backspin rather than that the moment Ix of inertia is increased on the assumption of miss shots. Further, it is also desirable that the club is sensitive about the golfer's swing motion, therefore, the moment Ix of inertia and shaft-torque are limited to small values. In the case of the golf clubs targeted at professionals and advanced golfers, the traditional design concepts would appear like that. [0005] On the contrary, high-handicapped golfers tend to make a hand swing as the body-led swing is difficult. Especially, the wrist is much more likely to move largely near the impact position. As a result, the swing path and ball hitting position become unstable. Thus, in the case of golf clubs targeted at high-handicapped golfers, on the assumption of miss shots, it is desirable that the club head is increased in the moment Ix of inertia as large as possible. As to the club shaft, on the other hand, it is considered as ideal that the torque is increased so as to cancel the variation of the golf club swing motions and also in order to increase the ball launch angle. In the case of a club shaft having a large torque, its twist can absorb unfavorable wrist motion, and thus the directional stability is not so decreased by the unfavorable wrist motion. During downswing from the top position, the club head is rotated around the shaft center line due to the twist of the club shaft, because the center of gravity of the club head is positioned at a certain distance from the shaft center line. Accordingly, the amount of the rotation becomes larger as the shaft-torque becomes larger. If this rotational motion is large, the ball launch angle becomes increased owing to the loft angle. [0006] In general, it is ideal that, during downswing from the top position, the club face is once largely opened, and the opened club face is gradually corrected so as to return the club face to square at impact. However, if the moment Ix of inertia is large, as the club head is hard to rotate, it is difficult to return the club face to square at impact, and the club face is liable to open at impact as shown in FIG. 6. Thus, there is a tendency for the high-handicapped golfers to further twist the wrist to make the club face at square, and as a result, the swing is further disturbed and the ball direction becomes unstable. SUMMARY OF THE INVENTION [0007] It is therefore, an object of the present invention to provide a golf club easy to use for high-handicapped golfers, in which the returning of the club face at impact and the head movement when missed a shot are improved and the directional stability is improved. [0008] According to the present invention a golf club comprises a golf club shaft and a golf club head attached to a tip end of the golf club shaft, wherein a moment Ix of inertia of the golf club head around a vertical axis passing through the center of gravity of the club head is not less than 3800 (gsq.cm), and a shaft-torque T (degrees) of the golf club shaft and the moment Ix of inertia satisfy the following condition (1): T=<0.0025.times.Ix-6.0. BRIEF DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 is a front view of a golf club according to the present invention showing a club head and a club shaft. [0010] FIG. 2 is a front view of the club head. [0011] FIG. 3 is a top view of the club head. [0012] FIG. 4 is a diagram for explaining a method of measuring a shaft-torque. [0013] FIG. 5 shows prepreg pieces used to make the club shaft. [0014] FIG. 6 is a diagram for explaining an inadequate returning of the club face at impact. DESCRIPTION OF THE PREFERRED EMBODIMENT(S) [0015] Embodiment of the present invention will now be described in detail in conjunction with the accompanying drawings. [0016] According to the present invention, golf club 1 comprises a club head 2 and a shaft 3 having an end attached to the head and a butt end provided with a grip 4. The golf club 1 is a wood type club inclusive of number one to five wood. The golf club 1 in this embodiment is a number one wood. [0017] The club head 2 comprises a face portion 2a whose front face defines a club face F for striking a ball, a crown portion 2b intersecting the club face F at the upper edge thereof, a sole portion 2c intersecting the club face F at the lower edge thereof, a side portion 2d between the crown portion and sole portion which extends from a toe-side edge to a heel-side edge of the club face through the back face of the club head, and a hosel portion 2e to be attached to an end of a club shaft 3. [0018] Here, the definitions of the undermentioned terms are provided: [0019] "Standard state" of the club head is that the club head is set on a horizontal plane HP so that the shaft center line CL is, within a vertical plane VP, inclined at its lie angle alpha with respect to the horizontal plane HP, and the club face F is inclined at its face angle beta with respect to the vertical plane VP, wherein the face angle beta is, as shown in FIG. 3, an angle between a horizontal tangential line N to the sweet spot SS on the club face F the vertical plane VP. [0020] "Sweet spot SS" is a point on the club face F which is the intersecting point of a straight line, which is drawn perpendicular to the club face F from the center G of gravity of the club head, with the club face F. Continue reading... Full patent description for Golf club Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Golf club patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Golf club or other areas of interest. ### Previous Patent Application: Directional practice device Next Patent Application: Golf putter Industry Class: Games using tangible projectile ### FreshPatents.com Support Thank you for viewing the Golf club patent info. IP-related news and info Results in 2.20739 seconds Other interesting Feshpatents.com categories: Medical: Surgery , Surgery(2) , Surgery(3) , Drug , Drug(2) , Prosthesis , Dentistry |
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