Games using tangible projectile – Golf – Club or club support
Reexamination Certificate
1999-03-16
2001-05-15
Chapman, Jeanette (Department: 3711)
Games using tangible projectile
Golf
Club or club support
C473S305000, C473S316000
Reexamination Certificate
active
06231457
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field
This invention pertains to golf club shafts, golf clubs, and methods for producing them. More particularly, it pertains to a nodal controlled kick-point lightweight golf club shaft for attachment to a lightweight golf club head made of titanium or other lightweight materials of similar or lessor density, and a method to produce the same.
2. State of the Art
Numerous lightweight golf club shafts and golf clubs are known. Conventional golf club drivers have heads weighing approximately 200-210 grams. In comparison, the newer lightweight titanium golf club drivers have heads weighing approximately 180-190 grams and require a lighter weight golf club shaft to lower the center of gravity of the club to provide better swing balance. Present lightweight golf club shafts are made of hollow tapered steel, which weigh approximately 120 grams, or hollow tapered graphite, which weigh approximately 95 grams. Czeck, U.S. Pat. No. 4,157,181 is an example of a typical narrow diameter graphite fiber tapered shaft having a handle end onto which are slid solid pre-wrapped and capped one-piece handles weighing approximately 46 to 52 grams. Inouet et al, U.S. Pat. No. 3,998,458 is another example of a typical narrow diameter graphite fiber tapered shaft generally having a dimension of 6 to 9 mm in diameter at the tip portion, and a 14-17 mm in diameter at the shaft butt portion onto which a solid one piece handle is inserted thereon. These solid one piece handles act to shift the center of gravity of the club toward the handle end; thus giving an unbalanced feel which also does not concentrate the weight of the club in the club head, during the swing.
Also, the flex of present graphite shafts is not adjusted to match the club head striking characteristics. Traditional wood and club head designs prevented the shaft from being located closer to the sweetspot (the clubheads' center of gravity). Thus anything less than a dead center impact caused the shaft, especially early graphite shafts, to over-torque, causing directional problems and less-than-perfect feel. To counteract this, graphite shafts had to be designed with stronger, heavier materials. This produced a stiffer, less-responsive shaft and a decrease in distance and feel, particularly for off-center hits.
In addition, the clubhead was not matched to the shaft's flexing characteristics. The easiest way to design a solid feeling, more forgiving clubhead is to drop the center of gravity very close to the sole of the club. This increases the amount of backspin, causing the ball to climb higher. Although this is effective, the trade off was a loss of forward momentum and excessive shot trajectory. High, short shots became the trademark of the standard metal wood design.
Newer 55-60 gram hollow graphite shafts, the solid one piece handles are even more top heavy, and accentuate the unbalanced feel. There therefore remains a need for a new shaft, club, and handle design to control the shaft torque and flex and concentrate the weight of the club in the club head to provide an optimum pendulum striking effect. The invention described below, provides such an improvement and method for making the same.
SUMMARY OF THE INVENTION
The invention comprises a low center of gravity golf club shaft for attachment to a lightweight golf club heads having a toe, heel, face, sole, and top made of titanium or similar or lower density material. The one piece combination handle and shaft is hollow and tapered, with the smaller club attachment end having a diameter for attachment to the driver heads of approximately 8.5 mm, and of approximately 9.4 mm for attachment to iron heads. Preferably the shaft is made of graphite wrapped with filament embedded in a resin matrix, or uni-direction tape angle wound to selectively stiffen and build up tapered nodes to allow the shaft to flex at pre-selected points along the shaft. These nodes also impede club torque on a miss hit shot. The wound, reinforced, shaft weighs approximately 55 to 65 grams. The shaft is preferably hollow to reduce the handle weight, but could also be of solid construction. The thickneses of the hollow shaft walls are sufficient to provide rigidity to the shaft to maintain its integrity during use. However, the actual shaft wall thicknesses vary depending upon the strength of the graphite and filament windings or tapes employed.
In conventional shafts, the flexpoint or angle of bend of the shaft (commonly referred to as the kick point of the shaft) varies considerably, depending upon shaft length, types of materials, swing types, and swing speed. This in turn materially affects the angle the club head meets the ball affecting the club performance. For example, with a short iron, it is desirable for the shaft to have a lower kick point such that the club face of the iron strikes at a greater angle under the ball to provide higher trajectory, and backspin to the ball. For drivers, a shaft with a higher kick point is desired to hit the ball at less of an angle to provide a lower trajectory with increased distance. Thus, the loft and spin of the ball is varied by using different club heads. For example, an iron with a low center of gravity and increased height of the club face provides higher loft and more backspin. Conversely, the driver employs a lesser angled club face and an increased club head height to raise the center of gravity of the club head and provide more distance and less backspin when hit. Thus if the kick point of the shaft does not match the club head, the hitting characteristics of the shot may be materially affected.
Both drivers and iron heads may also have increased widths to provide a more forgiving club head, which is easier to play, if miss hit. However, conventional shafts do not resist shaft torque, if the club miss hits the ball causing loss of performance.
Thus, control of the shaft kick point and torque is imperative to optimize the performance of the club. The kick point of the improved shaft is controlled by at least two built up tapered nodes placed on the lower one half to one-third of the shaft toward the club head. These tapered nodes are separated sufficiently apart to allow the shaft to bend therebetween at the desired flex point. These tapered nodes are built-up and made of the same materials as the shaft, and control the flex point angle of shaft bend so that the shaft angle that the club head meets the ball corresponds to the desired club face angle for optimal performance. The kick point of the shaft is thus controlled by the shaft tapered thicknesses between the nodes, the angle of windings of the two built up tapered nodes, and the stiffness of the materials and windings employed.
In addition, a third tapered node just below the handle may be included to dampen vibration of the club head hitting the ball. This third node also acts to provide balance to the club.
The shaft club attachment ends are attached to the club head proximate the heel via a recessed ferrule affixed to the club attachment end. The ferrule covered club attachment end is then inserted within a socket in the top of a no neck golf club head, or the neck of a golf club head. Golf club irons have necks to vary the angle of the face. These golf club iron necks are normally covered by a hosel. In the improved embodiment, the hosel of the golf club iron is shortened and the hosel on the wood is eliminated in favor of the recessed cushioned minimal weight ferrule to further lower the center of gravity of the golf club. The ferrule covers the shaft club attachment end to reinforce the club attachment end to prevent splitting and breakage of the shaft proximate its point of attachment to the head or iron. This ferrule is matched to each club head's hand beveled, progressively tapered bore. This ferrule adds strength to the shaft club attachment end by sitting down inside the club socket or neck to provide a 360-degree cushion that moves with the normal flexing and twisting of the shaft. This continuous cushioning prevents damage with the inside of the soc
Chapman Jeanette
Theodore Marcus G.
Varma Sneh
LandOfFree
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