GOLF CLUB SHAFT, GOLF PUTTER SHAFT, GOLF CLUB GRIP, GOLF CLUB SET AND GOLF CLUB

Abstract

The stiffness of the golf wood shaft is 210 to 240 CPM (5 cpm), the tip diameter is 8.4 to 9.4 mm, the weight is 40 to 70 g (3 g), the torque measurement at the shaft tip is adjusted to 8 to 6 degrees (0.2 deg), and the position of the center of gravity point of the shaft is set at 55% to 85% (5 mm) from the tip. If possible, with an indication of the center of gravity point of the shaft body or grip body, it is possible to manufacture a golf club that is easy to swing with a butt-heavy center of gravity. Furthermore, it is possible to propose a golf club that is kind and easy not only for professionals but also for amateur golfers.

Claims

1. A golf club shaft characterized in that a tip diameter of the golf club shaft is 8.4 to 9.4 mm, a weight of the golf club shaft is 40 to 100 g (3 g), and a position of the center of gravity point is at 55% to 85% (5 mm) from a tip of the golf club shaft.

2. The golf club shaft according to claim 1, the golf club shaft is a wood club shaft, characterized in that a stiffness of the golf club shaft is 210 to 240 CPM (5 cpm) and the weight of the golf club shaft is 40 to 70 g (3 g).

3. The golf club shaft according to claim 1, the golf club shaft is a wood club shaft, characterized in that the stiffness of the golf club shaft is 240 to 260 CPM (5 cpm) and the weight of the golf club shaft is 50 to 80 g (3 g).

4. The golf club shaft according to claim 1, the golf club shaft is a wood club shaft, characterized in that the stiffness of the golf club shaft is 260 to 270 CPM (5 cpm) and the weight of the golf club shaft is 60 to 100 g (3 g).

5. The golf club shaft according to claim 1, the golf club shaft is an iron club shaft, characterized in that the stiffness of the golf club shaft is 210 to 230 CPM (5 cpm), the tip diameter of the golf club shaft is 9.4 mm, and the weight of the golf club shaft is 50 to 70 g (3 g).

6. The golf club shaft according to claim 1, the golf club shaft is an iron club shaft, characterized in that the stiffness of the golf club shaft is 220 to 240 CPM (5 cpm), the tip diameter of the golf club shaft is 9.4 mm, and the weight of the golf club shaft is 60 to 90 g (3 g).

7. The golf club shaft according to claim 1, the golf club shaft is an iron club shaft, characterized in that the stiffness of the golf club shaft is 230 to 260 CPM (5 cpm), the tip diameter of the golf club shaft is 9.4 mm, and the weight of the golf club shaft is 70 to 120 g (3 g).

8. The golf club shaft according to claim 1, the golf club shaft is a putter shaft, characterized in that the tip diameter of the golf club shaft is 9.0 to 9.4 mm and the weight of the golf club shaft is 80 to 140 g (3 g).

9. The golf club shaft according to claim 1, characterized in that electroless plating is applied on the golf club shaft.

10. The golf club shaft according to claim 9, characterized in that the electric plating is copper plating.

11. The golf club shaft according to claim 9, characterized in that the electric plating is chrome plating.

12. The golf club shaft according to claim 9, characterized in that ion plating processing is further applied on a surface of the golf club shaft.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0036] FIG. 1 shows the swing and center of gravity position of the shaft.

[0037] FIG. 2 shows a carbon shaft for an iron set according to one embodiment of the present invention.

[0038] FIG. 3 shows a conventional carbon shaft for an iron set.

[0039] FIG. 4 shows a carbon shaft for an iron set according to another embodiment.

[0040] FIG. 5 shows a carbon shaft for a wood set according to one embodiment of the present invention.

[0041] FIG. 6 shows a tip-heavy carbon shaft for an iron set.

[0042] FIG. 7 shows a carbon shaft for a wood set according to another embodiment.

[0043] FIG. 8 shows the configuration of a putter shaft.

[0044] FIG. 9 is a schematic diagram showing a golf club grip according to one embodiment of the present invention.

[0045] FIG. 10 is a schematic diagram showing a golf club grip according to a specific example of the present invention.

[0046] FIG. 11 is a schematic diagram showing a golf club grip according to a specific example of the present invention.

[0047] FIG. 12 is a schematic diagram showing a golf club grip according to a specific example of the present invention.

[0048] FIG. 13 is a schematic diagram showing a golf club with the golf club grip applied.

[0049] FIG. 14 is a schematic diagram showing a conventional golf club grip.

DETAILED DESCRIPTION OF THE INVENTION

[0050] The embodiments of the present invention will be explained below based on the drawings. FIG. 1 shows the swing and center of gravity position of the shaft, FIG. 2 shows a carbon shaft for an iron set according to one embodiment of the present invention, and FIG. 3 shows a conventional carbon shaft for an iron set. In the following, golf club refers to a single club, golf club set refers to a set including several golf clubs of irons or woods, iron set refers to a set including several iron golf clubs, and wood set refers to a set including several wood golf clubs.

[0051] In sumo and golf sports, the stability of the center of gravity point (waist position) is more important than increasing body weight. In golf clubs as well, the change in the center of gravity point is more important than the weight feel of the shaft, contributing greatly to the stability of the swing, and is a very important factor. The inventor has confirmed from data from pros and competition-oriented golfers, based on over 50 years of experience in golf, that not only is the butt-heavy center of gravity on the grip side an important element for swing stability (operability), but there is also a need to adjust the ball's spin rotation, left-right deviation, and ease of catching the ball.

[0052] In the case of golf clubs, because the swing rotational movement becomes complex, it was confirmed that prioritizing the stability (operability) of the butt end of the shaft, which occupies an important part of the contact point between the golf club and the body, and the rhythm sense of the swing, is particularly meaningful. In other words, we focused on the fact that the center of gravity point of the shaft body strongly affects the operability of the golf club, and proceeded to create it. In this invention, to correspond to the subtle sensibilities of individual golfers, we focused on the center of gravity point rather than the weight or weight feel of the golf club shaft.

[0053] FIG. 1 shows a simplified view of the golfer's swing planes P1 and P2. In the figure, G indicates the center of gravity point, CD shows the position of the shaft at impact, and CU shows the position of the shaft in the process of lifting. Since the center of gravity point G becomes the center point when the shaft is pushed down by gravity, the distance from the grip during the swing has a significant impact on operability. And it can be understood that the distance from the grip is felt as the stability (operability) of the butt end of the shaft.

First Embodiment

[0054] FIG. 2 shows a carbon shaft for an iron set according to one embodiment of the present invention. It shows the total length, center position, center of gravity point position, center of gravity point position ratio, and distance from the center. The right side of the figure is the head side, and the left side of the figure is the grip side. The center of gravity point G represents the length from the head side. Therefore, if the center of gravity point G is longer than the center, the center of gravity point G will be closer to the grip side, resulting in a butt-heavy design. On the other hand, if the center of gravity point G is shorter than the center, the center of gravity point G will be closer to the head side, resulting in a tip-heavy design.

[0055] In this embodiment, we have adopted carbon shafts (CFRP) as an example for golf club shafts. Shafts that are made butt-heavy in the present invention can be GFRP shafts in addition to carbon shafts. The center of gravity point position ratio shows the ratio of the distance of the center of gravity point G from the grip side to the total length. The distance from the center shows the distance between the center of gravity point G and the center.

[0056] We prepared carbon shafts in 5 different weights (90 g, 100 g, 110 g, 120 g, 130 g). Golf clubs generally called iron sets correspond to this weight. The weight of carbon shafts can also be around 140 g.

TABLE-US-00001 Center of Center of gravity Distance Total length Center gravity position from Gravity (inches/cm) position position ratio center classification 39.0/99.1 49.5 cm 51.0 cm 48.5% 1.5 cm Butt-heavy 38.5/97.8 48.9 cm 50.5 cm 48.4% 1.6 cm Butt-heavy 38.0/96.5 48.3 cm 50.0 cm 48.2% 1.7 cm Butt-heavy 37.5/95.3 47.6 cm 49.5 cm 48.0% 1.9 cm Butt-heavy 37.0/94.0 47.0 cm 49.0 cm 47.9% 2.0 cm Butt-heavy 36.5/92.7 46.4 cm 48.5 cm 47.7% 2.1 cm Butt-heavy

[0057] General golfers are immature in both practice amount and sensibility. The butt-heavy center of gravity can be said to be a center of gravity position that prioritizes operability. Therefore, it is desirable to design such a center of gravity position to be butt-heavy for each club number of each club.

[0058] Also, in terms of whether it's butt-heavy or tip-heavy, even for carbon shafts of relatively short golf clubs that were butt-heavy by conventional manufacturing methods, from longer golf club carbon shafts to shorter golf club carbon shafts, by making the deviation of the center of gravity point position ratio small and making the distance of the center of gravity point position from the grip end shorter in proportion to the length, operability becomes easier.

[0059] Thus, for carbon shafts of golf clubs with a total length of 36.5 inches or more, the position of the center of gravity point in the length direction is closer to the grip side than the center of the total length. In this embodiment, the body weight is set to 90 g to 130 g, but as mentioned above, this is for iron sets. For wood sets to be described later, lighter ones are desired, and we created ones with a body weight of 50 g to 90 g.

[0060] Also, the position of the center of gravity point is within the range of 47 to 49% of the total length from the grip side. In this embodiment, we manufactured it to be within the range of 47 to 49% with an emphasis on stability. However, from the viewpoint of yield, it is possible to expand the range while keeping it butt-heavy. For this reason, the position of the center of gravity point can be set within the range of 46 to 49% of the total length from the grip side, or even within the range of 45 to 49% of the total length from the grip side. If the range expands like this, the yield during manufacturing can be improved.

[0061] FIG. 3 shows a conventional carbon shaft for an iron set. Conventionally, liquid resin is evenly impregnated into a shaft woven with carbon as the material, and it is formed by applying a predetermined pressure in a mold. As shown in the figure, conventional carbon shafts for golf clubs with a total length of 36.5 inches or more are tip-heavy. Carbon shafts for golf clubs with a total length of 36 inches or less are butt-heavy. This was inevitable as a result of evenly impregnating liquid resin into a shaft woven with carbon.

[0062] However, even with such a conventional position of the center of gravity point G, competition-oriented professional golfers are rich in both practice amount and sensibility, and there was no need to change the position of the center of gravity point G for each club number. However, for general golfers, it must be said that carbon shafts with such scattered center of gravity positions as in the conventional ones are difficult in both distance and operability.

TABLE-US-00002 Center of Center of gravity Distance Total length Center gravity position from Gravity (inches/cm) position position ratio center classification 39.0/99.1 49.6 cm 47.4 cm 54.3% 3.0 cm Tip-heavy 38.5/97.8 48.7 cm 46.7 cm 53.0% 1.6 cm Tip-heavy 38.0/96.5 48.3 cm 46.7 cm 52.1% 1.0 cm Tip-heavy 37.5/95.3 47.6 cm 46.6 cm 51.7% 0.2 cm Tip-heavy 37.0/94.0 47.0 cm 46.5 cm 50.0% 0.5 cm Tip-heavy 36.5/92.7 46.4 cm 46.0 cm 49.7% 1.6 cm Tip-heavy

[0063] As shown in the figure, in conventional golf club carbon shafts, the center of gravity point position ratio changes over a large range from 46.7% to 54.3%. Furthermore, what was butt-heavy on the short side changes to tip-heavy on the long side, and this change was also a major factor in making general golfers feel that long golf clubs are difficult to operate.

Second Embodiment

[0064] FIG. 4 shows a carbon shaft for an iron set according to another embodiment.

TABLE-US-00003 Center of Center of gravity Distance Total length Center gravity position from Gravity (inches/cm) position position ratio center classification 39.0/99.1 49.5 cm 50.6 cm 48.9% 1.1 cm Butt-heavy 38.5/97.8 48.9 cm 49.7 cm 49.2% 0.8 cm Butt-heavy 38.0/96.5 48.3 cm 49.3 cm 49.0% 1.0 cm Butt-heavy 37.5/95.3 47.6 cm 48.7 cm 48.9% 1.0 cm Butt-heavy 37.0/94.0 47.0 cm 48.0 cm 48.9% 1.0 cm Butt-heavy 36.5/92.7 46.4 cm 47.0 cm 49.3% 0.7 cm Butt-heavy

[0065] In this iron set, the center of gravity point position ratio is butt-heavy, falling within the range of 48.9% to 49.3% from the grip side (51.1% to 50.7% from the tip side). General golfers are immature in both practice amount and sensibility, so it is desirable to design the position of the center of gravity point G to be constant while prioritizing operability with a butt-heavy center of gravity. Here, constant refers to that the range of variation is very narrow, and in this example, it can be said to be almost 51%.

Third Embodiment

[0066] FIG. 5 shows a carbon shaft for a wood set according to one embodiment of the present invention.

TABLE-US-00004 Center of Center of gravity Distance Total length Center gravity position from Gravity (inches/cm) position position ratio center classification 46.0/116.8 58.4 cm 58.7 cm 49.8% 0.2 cm Butt-heavy 42.0/106.7 53.3 cm 53.6 cm 49.8% 0.2 cm Butt-heavy

[0067] In this wood set, the center of gravity point position ratio is butt-heavy at 49.8% from the grip side (50.2% from the tip side). We manufactured ones with a body weight in the range of 50 g to 90 g. Similar to the iron set, it is butt-heavy and the center of gravity point position ratio is constant, so for general golfers, the stability of rhythm feeling and operability improve.

[0068] On the other hand, by using the method of adjusting the center of gravity position by adding glass to the resin impregnated into the base tube for each predetermined part in the length direction, it has become possible to make adjustments more oriented towards advanced players rather than emphasizing stability for general golfers.

Fourth Embodiment

[0069] FIG. 6 shows a carbon shaft for an iron set that is tip-heavy.

TABLE-US-00005 Center of Center of gravity Distance Total length Center gravity position from Gravity (inches/cm) position position ratio center classification 39.0/99.1 49.6 cm 44.6 cm 55.0% 4.9 cm Tip-heavy 38.5/97.8 48.7 cm 43.8 cm 55.2% 5.2 cm Tip-heavy 38.0/96.5 48.3 cm 43.5 cm 55.0% 4.8 cm Tip-heavy 37.5/95.3 47.6 cm 43.0 cm 54.9% 4.6 cm Tip-heavy 37.0/94.0 47.0 cm 42.3 cm 55.0% 4.7 cm Tip-heavy 36.5/92.7 46.4 cm 41.5 cm 55.2% 4.9 cm Tip-heavy

[0070] In this iron set, the center of gravity point position ratio is tip-heavy, falling within the range of 54.9% to 55.3% from the grip side (54.7% to 55.1% from the tip side). This iron set is not butt-heavy, but the center of gravity point position is in the tip-heavy position. Even for weak or immature golfers with little practice, there is a preference for prioritizing distance. Tip-heavy sets have the advantage that the head runs well, so they become lighter overall and are preferable for general golfers or weak players. For this reason, while making it tip-heavy, to improve operability, we have designed a light club with the tip-heavy position as constant as possible.

[0071] The thickness, length, and weight of the carbon shaft are the same as conventional ones, but it is designed to be tip-heavy by adjusting the position of the weight.

Fifth Embodiment

[0072] FIG. 7 shows a carbon shaft for a wood set according to another embodiment. Wood sets emphasize directionality and operability, so they can be said to be golf clubs originally suited for competition-oriented golfers. However, tip-heavy sets can also be said to be preferable for general golfers or weak players because the head runs well, making them lighter overall. The thickness, length, and weight of the carbon shaft are the same as conventional ones, but it is designed to be butt-heavy and tip-heavy by adjusting the position of the weight.

TABLE-US-00006 Center of Center of gravity Distance Total length Center gravity position from Gravity (inches/cm) position position ratio center classification 46.0/116.8 58.4 cm 56.0 cm 52.1% 2.4 cm Tip-heavy 42.0/106.7 53.3 cm 47.3 cm 55.7% 6.0 cm Tip-heavy

[0073] In this wood set, the center of gravity point position ratio is tip-heavy, from 52.1 to 55.7% from the grip side (44.3 to 47.9% from the tip side). In this example, it is 45 to 48%, and considering processing errors, it can be made tip-heavy from 43% to 49%.

Sixth Embodiment

[0074] FIG. 8 shows the configuration of a putter shaft. This carbon shaft for putters has electroless plating applied to the surface of the carbon shaft body, followed by copper plating as electric plating on the surface. On the surface of this copper plating, decorative processing can be done as preferred to the extent that it does not affect the thickness of the copper plating. In other words, it consists of layers of electric plating (copper plating) part, electroless plating part, carbon shaft body (base tube), and electroless plating from the surface.

[0075] Carbon shafts, as an example of CFRP or GFRP, have a soft feel and a light image. First, the carbon shaft for putters in this embodiment had electroless plating applied to both front and back surfaces. By applying electroless plating, it becomes possible to apply metal plating afterwards. In this embodiment, copper plating was applied to the surface of the carbon shaft for putters that had electroless plating applied. By applying copper plating, it is possible to alleviate the anxiety of lightness towards carbon shafts for putters, and to make it feel like a weight somewhere between steel and carbon, somewhat similar to the feel of steel.

[0076] Also, there is a carbon feel, and the carbon feel, unlike steel, allows you to feel the weight of the head, which can prevent early hitting, pushing out, and pulling. Furthermore, because carbon has flexibility, the ball rolls well and extends. However, carbon alone is not preferable due to twisting. In this embodiment, by applying copper plating to the surface and further adjusting its thickness, twisting can be suppressed. Therefore, it can be hit with a steel-like feel, improving directionality. When using a putter, it is often hit off-center, so being resistant to impact point deviation can prevent mistakes and have a positive effect on improving scores. Next, we will explain examples of golf club shafts where the position of the center of gravity point is within the range of 15 to 45% of the total length from the grip side, that is, within the range of 55 to 85% of the total length from the head side.

Seventh Embodiment

[0077] The measurement values of the golf club shaft in this embodiment are as follows: [0078] Stiffness of golf wood shaft: 210 to 240 CPM (5 cpm) [0079] Tip diameter: 8.4 to 9.4 mm [0080] Weight: 40 to 70 g (3 g) [0081] Torque measurement at the shaft tip is adjusted to 8 to 6 degrees (0.2 deg). [0082] The position of the center of gravity point of the shaft is at 55% to 85% (5 mm) from the tip.

[0083] By using such a golf club shaft, it is possible to manufacture a golf club that is easy to swing with a butt-heavy center of gravity. Note that for torque measurement, it is shown as a more preferable example.

Eighth Embodiment

[0084] The measurement values of the golf club shaft in this embodiment are as follows: [0085] Stiffness of golf wood shaft: 240 to 260 CPM (5 cpm) [0086] Tip diameter: 8.4 to 9.4 mm [0087] Weight: 50 to 80 g (3 g) [0088] Torque measurement at the shaft tip is adjusted to 5 to 4 degrees (0.2 deg). [0089] The position of the center of gravity point of the shaft is at 55% to 85% (5 mm) from the tip.

[0090] By using such a golf club shaft, it is possible to manufacture a golf club that is easy to swing with a butt-heavy center of gravity. Note that for torque measurement, it is shown as a more preferable example.

Ninth Embodiment

[0091] The measurement values of the golf club shaft in this embodiment are as follows: [0092] Stiffness of golf wood shaft: 260 to 270 CPM (5 cpm) [0093] Tip diameter: 8.4 to 9.4 mm [0094] Weight: 60 to 100 g (3 g) [0095] Torque measurement at the shaft tip is adjusted to 3 to 2 degrees (0.2 deg).

[0096] The position of the center of gravity point of the shaft is at 55% to 85% (5 mm) from the tip.

[0097] By using such a golf club shaft, it is possible to manufacture a golf club that is easy to swing with a butt-heavy center of gravity. Note that for torque measurement, it is shown as a more preferable example.

Tenth Embodiment

[0098] The measurement values of the golf club shaft in this embodiment are as follows: [0099] Stiffness of golf iron shaft: 210 to 230 CPM (5 cpm) [0100] Tip diameter: 9.4 mm [0101] Weight: 50 to 70 g (3 g) [0102] Torque measurement at the shaft tip is adjusted to 8 to 6 degrees (0.2 deg).

[0103] The position of the center of gravity point of the shaft is at 55% to 85% (5 mm) from the tip.

[0104] By using such a golf club shaft, it is possible to manufacture a golf club that is easy to swing with a butt-heavy center of gravity. Note that for torque measurement, it is shown as a more preferable example.

Eleventh Embodiment

[0105] The measurement values of the golf club shaft in this embodiment are as follows: [0106] Stiffness of golf iron shaft: 220 to 240 CPM (5 cpm) [0107] Tip diameter: 9.4 mm [0108] Weight: 60 to 90 g (3 g) [0109] Torque measurement at the shaft tip is adjusted to 5 to 4 degrees (0.2 deg).

[0110] The position of the center of gravity point of the shaft is at 55% to 85% (5 mm) from the tip.

[0111] By using such a golf club shaft, it is possible to manufacture a golf club that is easy to swing with a butt-heavy center of gravity. Note that for torque measurement, it is shown as a more preferable example.

Twelfth Embodiment

[0112] The measurement values of the golf club shaft in this embodiment are as follows: [0113] Stiffness of golf iron shaft: 230 to 260 CPM (5 cpm) [0114] Tip diameter: 9.4 mm [0115] Weight: 70 to 120 g (3 g) [0116] Torque measurement at the shaft tip is adjusted to 3 to 2 degrees (0.2 deg).

[0117] The position of the center of gravity point of the shaft is at 55% to 85% (5 mm) from the tip.

[0118] By using such a golf club shaft, it is possible to manufacture a golf club that is easy to swing with a butt-heavy center of gravity. Note that for torque measurement, it is shown as a more preferable example.

Thirteenth Embodiment

[0119] The measurement values of the golf club shaft in this embodiment are as follows: [0120] Tip diameter of golf putter shaft: 9.0 to 9.4 mm [0121] Weight: 80 to 140 g (3 g) [0122] Torque measurement at the shaft tip is adjusted to 8 to 2 degrees (0.2 deg).

[0123] The position of the center of gravity point of the shaft is at 55% to 85% (5 mm) from the tip.

[0124] By using such a putter club shaft, it is possible to manufacture a golf putter that is easy to control and swing with a butt-heavy center of gravity. Note that for torque measurement, it is shown as a more preferable example.

Fourteenth Embodiment

[0125] The suitable grip for use with such golf club shafts is as follows:

[0126] The measurement values of the golf club grip in this embodiment are as follows: [0127] Total weight of grip: 25 to 150 g [0128] Center of gravity position is within the range of 65 to 85% (5 mm) from the tip [0129] The range up to 70% from the grip end is made of rubber-related materials.

[0130] The range up to 30% from the grip tip uses leather-related materials including synthetic leather.

[0131] Because carbon shafts use fibers as their basic material, they tend to twist easily. Therefore, it is a reality that professionals and competition-oriented golfers often use steel shafts with less twisting not only for putters but also for many golf clubs.

[0132] It is also a fact that not only competition-oriented golfers but also general amateur golfers are recommended to use heavy steel shafts. This can be said to be unfavorable in terms of various health issues from continuously swinging heavy clubs not only for long hours but also over long periods, including practice. It is a well-known fact that there is a focus on making shafts and grips lighter to increase distance for beginners, juniors, and senior golfers. Also, it is true that many people, after seeing or hearing information and advertisements about clubs used by pros or competition-oriented golfers who practice a lot regularly, ignore the center of gravity point of clubs and shafts, misunderstand that using such clubs will magically improve their skills even as beginners, and rush to buy new products.

[0133] Regarding the adjustment of shaft torque angle, specifically for adjustments of 2 to 8 degrees of torque, by adopting low to high elastic carbon fiber wraps or boron fibers in the internal design of carbon shafts, it becomes possible to easily adjust and tailor to individual golfers' power and swing speed. Conventional tip-heavy clubs, especially when the shaft is light, the grip is light, and the entire club becomes light, run well at the head and produce good distance, which seems impressive, but the ball tends to deviate left and right and doesn't go as intended.

[0134] Even with such clubs, through harsh practice, one might achieve a somewhat straight flight and desired trajectory, but in a situation where one has to work hard in practice to enjoy such golf, unless one is willing to devote themselves to golf practice even at great expense or is a wealthy golfer, it is difficult to enjoy golf. Conventional clubs with the center of gravity from the tip to near the center and slightly closer to the butt are designed as a natural course, and shafts are currently being produced ignoring the issue of the center of gravity point. In the past and present, in the important specifications for manufacturing golf shafts worldwide, there are no shafts that specifically indicate the position of the center of gravity point. With the shafts of this invention, clubs based on this butt center of gravity point specification, if used with adjusted weight, stiffness, and torque, can become clubs that allow sufficient enjoyment of golf without excessive practice.

[0135] Next, we will explain examples of golf club grips. FIG. 9 is a schematic diagram showing a golf club grip according to one embodiment of the present invention. In this figure, the golf club grip 10 of the present invention has a tip diameter of 15 to 16 mm and a weight of 40 to 100 g (3 g). The position of the center of gravity point of this grip 10 is at 66% to 85% from the tip of the grip, that is, from the head side. The weight of the grip can be in the range of 25 to 150 g.

[0136] However, it is not easy to move the center of gravity point towards the grip end without increasing the weight of the grip alone, and more realistically, the position of the center of gravity point of the grip of this invention may be within the range of 66% to 80% from the head side. Since the position of the center of gravity point is quite close to the end side of the total length of the grip, the stability of the swing improves. When moving the center of gravity point towards the grip end like this, it is preferable to move the center of gravity point without increasing the overall weight.

[0137] As an example of this method, FIG. 10 shows a grip 20 with a composition that is partially different, that is, partially different materials in the length direction. Specifically, the head side region 21 is formed with a light composition, and the grip end side region 22 is formed with a heavy composition.

[0138] Also, FIG. 11 shows a grip 30 formed by intertwining two compositions 31, 32 with different specific gravities like a double thread. In this case, rather than changing the material in the length direction, the center of gravity point is moved by partially changing the composition ratio. Specifically, on the head side, the composition ratio of composition 32 is larger than that of composition 31, and on the grip end side, the composition ratio of composition 31 is larger than that of composition 32. Even with this method, it can be said that the main composition on the head side and the main composition on the end side are different.

[0139] Furthermore, in parallel with these, for example, when forming anti-slip grooves on the surface, making the grooves larger on the head side and smaller on the grip end side also contributes to moving the center of gravity point. Specifically, by making the head side a so-called concave finish and the grip end side a so-called convex finish, the center of gravity point can be moved towards the grip end side.

[0140] Next, FIG. 12 schematically shows a golf club grip with partially different surface materials. In this grip 40, the surface material of the tip side 41 of grip 40 is leather or synthetic leather, etc., and the grip end side 42 is rubber products or silicone products. Changing the surface material also contributes to moving the center of gravity point towards the grip end side. In this example, it is good if leather or synthetic leather, etc., is lighter than the rubber products on the grip end side.

[0141] In addition to moving the center of gravity point, by adding leather or synthetic leather, etc., to the surface of the tip side of the grip, resulting in two different surface materials on the grip, stability and control were improved. A tendency was obtained where adopting leather products rather than the non-slip characteristic of rubber products for the tip side 41 of grip 40 is preferred to utilize the subtle sensation of fingertips. Specifically, it is difficult with rubber products to feel the smooth flow of the swing with the fingertips.

[0142] We have confirmed that for the flow of golf swings as well, just like smooth steering of a car, using leather products for the parts where fingertips touch assists the smooth flow of the grip, providing a comfortable sensation for fingertips and palms. As a specific example appealing to sensation like this, while leather or synthetic leather, etc., is adopted on the head side, it is also good to make the friction coefficient of the surface different between the head side and the end side, with the tip side having a smaller friction coefficient. Specifically, this can be realized by changing materials or altering the anti-slip pattern on the surface.

[0143] For the purpose of moving the center of gravity as well, for example, make the surface friction coefficient smaller on the tip side for at least the range up to a maximum of 40% from the tip on the head side and at least the range up to a maximum of 60% from the end side. If necessary, the surface friction coefficient may be made smaller on the tip side for at least the range up to a maximum of 30% from the tip on the head side and at least the range up to a maximum of 70% from the end side.

[0144] As mentioned earlier, in sumo and golf sports, the stability of the center of gravity point (waist position) is more important than increasing body weight. In golf clubs as well, the change in the center of gravity point contributes more to the stability of the swing than the weight feel of the shaft and is a very important factor. In the case of golf clubs, because the swing rotational movement becomes complex, we confirmed that prioritizing the stability (operability) of the butt end of the shaft, which occupies an important part of the contact point between the golf club and the body, is particularly meaningful.

[0145] However, the heavier the overall weight of the grip, the more the center of gravity point of the golf club moves towards the butt end, reaching an ideal position. In this case, while the center of gravity position becomes close to ideal, not only does the overall weight of the grip increase but the entire club becomes heavier, leading to quicker fatigue and a decrease in swing speed. Also, because the center of gravity point as a club moves further towards the head, not only operability but also distance becomes unstable.

[0146] Furthermore, not only does the swing speed decrease, but as time passes, stamina is also consumed, resulting in the disadvantage of instability not only in distance but also in directionality. This invention can make swings easier by making the grip that golfers conventionally use even slightly lighter while moving the center of gravity point of the club towards the grip end side, improving not only operability but also rhythm sense and enabling distance.

[0147] In other words, while premising on making it as light as possible, if the center of gravity point is not moved towards the grip end side, not only operability but also distance will decrease. Also, what strongly affects the operability of a golf club is not only the center of gravity point of the shaft body, but to correspond to the subtle fingertip and palm sensibilities of individual golfers, we focused not only on the weight or weight feel of the golf club shaft, but also on the center of gravity point of the shaft, along with the center of gravity point of the grip and two types of textures of rubber and leather materials.

[0148] Thus, this invention designed not only the center of gravity point but also the hand slip during swings, separating the palm and fingertips. We felt the need to improve the surface part of the grip body divided into palm and fingertip parts. Specifically, for the range of 50 to 70% from the tip (where the thumb, index finger, and middle finger touch), a design with plain, smooth, and light material is good. This is because many people are dexterous with their fingertips, and unnecessary force tends to be applied to the flow during the swing, so it needs to be made as slippery as possible.

[0149] On the other hand, for the remaining end part, it is desirable to design with unevenness, using hard and soft materials on either the concave or convex side. By doing so, it will suppress the slipping of the palm as much as possible, resulting in a grip that is more stable, less prone to deviation, and smoother in operation.

[0150] The suitable grip for use with such golf club shafts is as follows: [0151] The measurement values of the golf club grip in this embodiment are as follows: [0152] Total weight of grip: 25 to 150 g [0153] Center of gravity position is within the range of 65 to 80% (1 mm) from the tip [0154] The range of 60 to 70% from the grip end is made of rubber-related materials. [0155] The range of 30 to 40% from the grip tip uses leather-related materials including synthetic leather.

[0156] FIG. 13 is a schematic diagram showing a golf club with the golf club grip applied. Suppose that the grip 51 of this golf club 50 has moved its center of gravity point Gg1 towards the grip end side compared to the center of gravity point Gg0 of conventional grips, without increasing weight. Then, the center of gravity point of the golf club 50 equipped with this grip 51, which would have been at center of gravity point Gc0 conventionally, moves to center of gravity point Gc1 as the grip 51 moves its center of gravity point without increasing weight. This golf club 50 has a weight of 25 to 150 g and is equipped with a grip whose center of gravity position is within the range of 66 to 85% from the tip on the head side, with the position of the center of gravity being at 50% or more towards the grip side relative to the total length of the golf club.

[0157] By applying this invention, it is possible to produce a butt-heavy effect focused not only on the shaft of the golf club but also together with the grip.

[0158] It goes without saying that this invention is not limited to the above embodiments. It is needless to say for those skilled in the art that:

[0159] Applying by appropriately changing the combination of interchangeable components and configurations disclosed in the above embodiments

[0160] Appropriately replacing and applying components and configurations not disclosed in the above embodiments but known in the art and interchangeable with components and configurations disclosed in the above embodiments, or changing their combinations

[0161] Appropriately replacing and applying components and configurations that those skilled in the art can assume as substitutes for components and configurations disclosed in the above embodiments based on known technologies not disclosed in the above embodiments, or changing their combinations are disclosed as embodiments of this invention.

Description of the Reference Numerals

[0162] P1, P2: Swing plane, G: Center of gravity point position, 10: Grip, 20: Grip, 21: Head side region, 22: Grip end side region, 30: Grip, 31, 32: Composition, 40: Grip, 41: Tip side, 42: Grip end side, 50: Golf club, 51: Grip