Patent Application
20250099824
This patent specification is based on Japanese patent application, No. 2023-158509 filed on Sep. 22, 2023 in the Japan Patent Office, Japanese patent application, No. 2023-215432 filed on Dec. 21, 2023 in the Japan Patent Office, Japanese patent application, No. 2024-151374 filed on Sep. 3, 2024 and Japanese patent application, No. 2024-151375 filed on Sep. 3, 2024 in the Japan Patent Office, the entire contents of which are incorporated by reference herein.
The present invention relates to a golf club shaft, a golf putter shaft, a golf club grip, a golf club set, and a golf club.
Multiple golf clubs with different lengths are provided according to flying distance. The center of gravity and spin effect of a golf club naturally change depending on the weight and center of gravity point of the golf shaft itself, the weight and center of gravity point of the grip and head, the stiffness of the shaft, and torque value of the shaft. Conventional golf clubs disclosed in Patent Document 1 focus on the center of gravity of the entire club, and there is no indication of the center of gravity point of the golf club shaft alone. Even in the iron golf club shown in Patent Document 1, the center of gravity is focused on, and the position of the center of gravity is set at about 76.5% to 79.5% of the total length of the golf club toward the head side. When actually measuring the center of gravity point of a golf club shaft, except for short ones in the range of 9 to 7 irons, it was at a position biased toward the head side relative to the total length of the shaft. Even for short ones in the range of 9 to 7 irons, the center of gravity point of the shaft was less than 60% from the head side at most.
In addition, multiple golf grips with different weights and lengths are provided according to the golf club.
Regardless of the material, the position of the center of gravity of golf clubs called irons and woods is at a position biased toward the head side from the center relative to the total length of the golf club, except for short golf clubs. There are also some for advanced players that intentionally bring the center of gravity position closer to the head by attaching weights to the golf shaft. When the position of the center of gravity is biased toward the head side relative to the total length of the golf club like this, it feels heavy when swinging the golf club, making operability and reproducibility difficult. Except for professional golfers who can secure frequent practice time on a regular basis, it is difficult for beginners and intermediate players to hit accurate shots with longer golf clubs. For this reason, in iron sets, short irons in the range of 9 to 7 irons are often used, and longer irons of 6 iron and below are becoming unused. Conventionally, it was not possible to adjust the center of gravity with the golf club shaft, so the swing balance sense of the golf club as a whole, specifically numerical values of C5 to D5 are common. In addition, the golf club grip is necessary not only for slip prevention but also for buffering the impact from the shaft at the time of hitting. The grip has only been focused on for buffering and slip prevention at the time of hitting, and furthermore, the position of the center of gravity was naturally determined by the material and shape, and there was no recognized need to change it.
Those with a center of gravity position close to the head side from the center of the total length are called tip-heavy, and those with a center of gravity point position in the length direction close to the grip side from the center of the total length are called butt-heavy.
The present invention provides a golf club shaft, a golf putter shaft, a golf club grip, a golf club set, and a golf club that are easy to handle not only for beginners and intermediate players but also for advanced players.
The golf club shaft of the present invention is a CFRP or GFRP golf club shaft with a body weight of 50 g to 140 g and a total length of 36.5 inches or more, wherein the position of the center of gravity point in the length direction is set closer to the grip side than the center of the total length. In conventional golf clubs with a total length of 36.5 inches or more, the center of gravity position was naturally at a position closer to the head side than the center of the total length. In the above configuration, in the CFRP or GFRP golf club shaft, the position of the center of gravity point in the length direction is set closer to the grip side than the center of the total length. The conventional ones are called tip-heavy, and the present invention is called butt-heavy.
Since the position of the center of gravity point is closer to the grip side than the center of the total length, the swing stability improves like golf clubs with a total length of less than 36.5 inches. In another aspect of the present invention, the position of the center of gravity point or kick point is within the range of 45 to 49% of the total length from the grip side. In the above configuration, to make it butt-heavy while improving swing stability, the position of the center of gravity point is set within the range of 45 to 49% of the total length from the grip side. As a more preferable range for improving stability, the position of the center of gravity point may be set within the range of 46 to 49% of the total length from the grip side. As an even more preferable range, the position of the center of gravity point may be set within the range of 47 to 49% of the total length from the grip side.
In another aspect of the present invention, the center of gravity position is adjusted by resin or heavy metals with high specific gravity impregnated into the base tube for each predetermined part in the length direction. In the above configuration, for carbon shafts of golf clubs with a body weight of 50 g to 140 g and a total length of 36.5 inches or more, they naturally become tip-heavy by conventional manufacturing methods. However, it is possible to adjust the center of gravity position by adding resin or heavy metal systems impregnated into the base tube for each predetermined part in the length direction. Also, since it is adjusted by impregnated prepreg, the shaft can maintain a true circle with respect to the axis center.
In another aspect of the present invention, electroless plating is applied. In the above configuration, carbon shafts are made by bundling fibers, so they tend to twist easily, but by applying electroless plating on the surface, they become less likely to twist even though the inside is a fiber bundle.
In another aspect of the present invention, electric plating is applied on the surface of the electroless plating to make it double plated. In the above configuration, by applying electroless plating, it becomes possible to apply electric plating on its surface. Electric plating allows easy thickness increase, making it possible to utilize the lightweight core of the base tube while enabling weight adjustment.
In another aspect of the present invention, the electric plating is copper plating. In another aspect of the present invention, the electric plating is chrome plating.
In another aspect of the present invention, it is a golf club set including golf clubs formed with shafts as described above. In the above configuration, it becomes a golf club set that is easy to swing by making short golf clubs to long golf clubs butt-heavy. On the other hand, as a carbon shaft for golf clubs for advanced players, it can be configured to have a body weight of 50 g to 140 g, and the position of the center of gravity point in the length direction is within the range of 43 to 49% of the total length from the tip side for CFRP or GFRP shafts of golf clubs.
It is also possible to configure a CFRP or GFRP shaft for a golf putter by applying electroless plating on the surface of the underlying carbon shaft and adding electric plating on its surface. It is possible to easily adjust the center of gravity position and weight while using CFRP or GFRP shafts.
Furthermore, the golf club shaft of the present invention has a tip diameter of 8.4 to 9.4 mm, a weight of 40 to 100 g (±3 g), and the position of the center of gravity point is at a position 55% to 85%, preferably 60% to 80% (±5 mm) from the tip. Hereinafter, the second golf club shaft refers to this golf club shaft. Since the position of the center of gravity point is quite close to the grip side from the center of the total length, swing stability improves by setting the position of the center of gravity point in the length direction within the range of 45 to 49% of the total length from the grip side as in other aspects, but it was still a bit difficult for golf beginners or weak golfers.
In another aspect of the present invention, the position of the center of gravity point is within the range of 55% to 85%, preferably 60 to 80% (±5 mm) of the total length of the shaft body from the tip head side. However, it is possible to correct the up and down adjustment of the ball by adjusting the center of gravity point position and kick point. Regarding the torque angle, by using a range of 8 to 2 degrees for the torque angle from weak people to competition-oriented people, it becomes possible to easily correct the left and right of the ball by spin.
In another aspect of the present invention, the golf club shaft according to the second golf club shaft, being a wood club shaft, characterized in that the stiffness is 210 to 240 CPM (±5 cpm) and the weight is 40 to 70 g (±3 g).
Further, in another aspect of the present invention, the golf club shaft according to the second golf club shaft, being a wood club shaft, characterized in that the stiffness is 240 to 260 CPM (±5 cpm) and the weight is 50 to 80 g (±3 g).
Further, in another aspect of the present invention, the golf club shaft according to the second golf club shaft, being a wood club shaft, characterized in that the stiffness is 260 to 270 CPM (±5 cpm) and the weight is 60 to 100 g (±3 g).
Further, in another aspect of the present invention, the golf club shaft according to the second golf club shaft, being an iron club shaft, characterized in that the stiffness is 210 to 230 CPM (±5 cpm), the tip diameter is 9.4 mm, and the weight is 50 to 70 g (±3 g).
Further, in another aspect of the present invention, the golf club shaft according to the second golf club shaft, being an iron club shaft, characterized in that the stiffness is 220 to 240 CPM (±5 cpm), the tip diameter is 9.4 mm, and the weight is 60 to 90 g (±3 g).
Further, in another aspect of the present invention, the golf club shaft according to the second golf club shaft, being an iron club shaft, characterized in that the stiffness is 230 to 260 CPM (±5 cpm), the tip diameter is 9.4 mm, and the weight is 70 to 120 g (±3 g).
Further, in another aspect of the present invention, the golf club shaft according to the second golf club shaft, being a putter shaft, characterized in that the tip diameter is 9.0 to 9.4 mm and the weight is 80 to 140 g (±3 g).
Further, in another aspect of the present invention, the golf club shaft according to the second golf club shaft, characterized in that electroless plating is applied. Such electric plating can be copper plating or chrome plating. And ion plating processing can be further applied on the surface of the shaft.
In addition to moving the center of gravity point, by adding leather or synthetic leather to the surface of the tip side of the grip, resulting on two different surface materials on the grip, stability and control were improved.
In another aspect of the present invention, the center of gravity position is adjusted by adding glass to the resin impregnated into the base tube for each predetermined part in the length direction, specifically by adding materials with high specific gravity such as glass to the resin impregnated into carbon fibers for each predetermined part in the length direction to adjust the center of gravity position. By conventional manufacturing methods, it naturally becomes tip-heavy from around the center. However, it becomes possible to adjust the center of gravity position by adding prepreg of glass or heavy metal systems impregnated into the base tube for each predetermined part in the length direction. Also, since it is adjusted by impregnated resin or metals, the shaft can maintain a true circle with respect to the axis center.
In another aspect of the present invention, it is a golf club set including golf clubs formed with shafts as described above. In the above configuration, it becomes a golf club set that is easy to swing with good operability by making short golf clubs to long golf clubs butt-heavy. On the other hand, for carbon shafts of golf clubs for advanced players, reinforcement is needed to make the shaft harder towards the head side direction from around the center.
In the golf club grip of the present invention, the weight is 25 to 150 g, and the center of gravity position is within the range of 66 to 85% from the tip on the head side. In the above configuration, for grips with a weight of 25 to 150 g, the center of gravity position is within the range of 66 to 85% from the tip on the head side, so compared to conventional grips where it was at 60%, the center of gravity position of golf clubs using this golf grip of the present invention becomes closer to the butt end.
Furthermore, the present invention has a configuration where the main component on the head side and the main component on the end side are different. Changing the center of gravity position is possible by changing the material of the golf grip. Since the material of the grip end often differs, the material is changed on the part that contacts the side surface of the golf shaft. By making the main component on the head side and the main component on the end side different, and making the main component on the head side lighter and the main component on the end side heavier, the center of gravity position can be changed. Changing the material can also simultaneously achieve changing the friction coefficient of the surface, as described later. It also includes making the golf grip separate parts for the head side part and the grip end side part. In this case, it is sufficient to specify the center of gravity position as an integrated state.
The present invention also has a configuration where the center of gravity position is within the range of 66 to 80% from the tip on the head side. Furthermore, the present invention has a configuration where, at least in the range up to a maximum of 40% from the tip on the head side and at least in the range up to a maximum of 60% from the end side, the friction coefficient of the surface is smaller on the tip side. The present invention also has a configuration where, at least in the range up to a maximum of 30% from the tip on the head side and at least in the range up to a maximum of 70% from the end side, the friction coefficient of the surface is smaller on the tip side.
Furthermore, the present invention has a configuration where at least the range up to a maximum of 40% from the tip on the head side is leather or synthetic leather on the surface, and at least the range up to a maximum of 60% from the end side is rubber or silicone on the surface. The present invention also has a configuration where the leather or synthetic leather on the head side is lighter than the rubber or silicone on the end side. Furthermore, the present invention has a configuration of a golf club where the weight is 25 to 150 g, the center of gravity position is within the range of 66 to 85% from the tip on the head side of the grip, and the position of the center of gravity is at a position 50% or more towards the grip side relative to the total length of the golf club. In this way, according to the present invention, with the grip alone, it is possible to move the center of gravity point towards the grip end side and move the center of gravity point of the entire club towards the grip end side. Since the center of gravity position of the golf club moves towards the butt end, operability and reproducibility improve when swinging the golf club. On the other hand, although attaching a counterbalance can move the center of gravity point towards the grip end side, the overall weight of the club increases. In the present invention, the center of gravity point is moved towards the grip end side without changing the weight of the grip alone.
According to the present invention, it is possible to provide a golf club shaft, a golf putter shaft, a golf club grip, and a golf club set that are easy to handle for beginners and intermediate players.
The embodiments of the present invention will be explained below based on the drawings.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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%.
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.
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.
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.
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.
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%.
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.
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.
The measurement values of the golf club shaft in this embodiment are as follows:
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.
The measurement values of the golf club shaft in this embodiment are as follows:
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.
The measurement values of the golf club shaft in this embodiment are as follows:
The position of the center of gravity point of the shaft is at 55% to 85% (±5 mm) from the tip.
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.
The measurement values of the golf club shaft in this embodiment are as follows:
The position of the center of gravity point of the shaft is at 55% to 85% (±5 mm) from the tip.
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.
The measurement values of the golf club shaft in this embodiment are as follows:
The position of the center of gravity point of the shaft is at 55% to 85% (±5 mm) from the tip.
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.
The measurement values of the golf club shaft in this embodiment are as follows:
The position of the center of gravity point of the shaft is at 55% to 85% (±5 mm) from the tip.
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.
The measurement values of the golf club shaft in this embodiment are as follows:
The position of the center of gravity point of the shaft is at 55% to 85% (±5 mm) from the tip.
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.
The suitable grip for use with such golf club shafts is as follows:
The measurement values of the golf club grip in this embodiment are as follows:
The range up to 30% from the grip tip uses leather-related materials including synthetic leather.
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.
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.
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.
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.
Next, we will explain examples of golf club grips.
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.
As an example of this method,
Also,
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.
Next,
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.
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.
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.
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.
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.
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.
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.
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.
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.
The suitable grip for use with such golf club shafts is as follows:
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.
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:
Applying by appropriately changing the combination of interchangeable components and configurations disclosed in the above embodiments
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
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-158509 | Sep 2023 | JP | national |
| 2023-215432 | Dec 2023 | JP | national |
| 2024-151374 | Sep 2024 | JP | national |
| 2024-151375 | Sep 2024 | JP | national |
