WO2002047771A1

WO2002047771A1 - Golf club

Info

Publication number: WO2002047771A1
Application number: PCT/SE2001/002727
Authority: WO
Inventors: Stein G. Ahlqvist
Original assignee: Ahlqvist Stein G
Priority date: 2000-12-12
Filing date: 2001-12-10
Publication date: 2002-06-20
Also published as: SE518176C2; SE0004592D0; EP1345660A1; US20040038745A1; AU2002221240A1; SE0004592L

Abstract

The invention relates to a golf club (1) comprising a shaft (3) provided with a handle portion (2) and a club blade (5) projecting from the lower portion (4) of said shaft (3), the hitting surface (6) of said blade is provided with a plurality of scores or grooves (7). Those grooves (7) are arranged at a predetermined mutual distance and do extend in a diverging or parallel pattern or area over at least the hitting surface (6) of the club blade (5).

Description

Golf club

The present invention relates to a golf club which comprises a shaft, provided with a handle portion, and a club blade projecting from the lower portion of the shaft, a plurality of depressions or grooves extending across the hitting surface of the blade .

The golf clubs which today are available in the market do, practially all of them, on the hitting surface on the club blade exhibit some form of patterns or grooves, the primary purpose of which is to increase the friction and accordingly also inter alia the ball backspin generated in the hitting moment between the club blade and the golf ball. In those cases when a golf ball is hit exactly in the correct point on a standard club blade and with a correct force, which can never be guaranteed, the golf ball travels to the intended spot and the player can use any standard club to reach a completely satisfactory result . If, however, when a conventional standard club hits the ball above the ideal hit point the ball will travel a shorter distance than intended due to the fact that this portion of the blade moves slower than the central point because in that case the radius of the rotation circle of the club blade is shorter. The opposite will occur when the ball hits a standard blade at its lower part meaning that in this case the ball will travel farther than desired because the radius of the rotational circle of the club blade will be greater. The difference in terms of speed between the upper and the lower point on the blade amounts to a number of significant percent values. In addition thereto attention^' has to be paid to the fact that when a stroke is made and the lower portion of. the blade hits the ball the blade will move at the higher speed, also due to the fact that in this case the blade cuts less or not at all down in the ground. When this occurs there will be generated a certain resistance which reduces the speed. On the other hand, if the upper portion of the blade hits the ball, the soil will always present a resistance because the blade does then dig itself deeper down than ideal . Irrespective of how the club blade hits the ball the latter is all the time at the same distance from the solid support layer. The perfect stroke, a so called "square hit" does not exist in reality because the movement of the golf player's hips is slower than the club blade movement through the air. Consequently, a club blade moves almost exactly along the periferi of its rotational circle in response to a stroke and, for this reason, the ball travelling distance will be different in response to the location of the golf ball hitting point on a standard blade .

The object of the present invention is to provide a golf club of the type mentioned above which comprises a club blade having grooves on its hitting surface, said grooves being oriented in such a way that the problems existing in the prior art golf club have been eliminated. The characteristic features of the invention are set out in the patent claims .

Thanks to the invention there has now been provided a golf club which in an excellent manner satisfies the demands and, in addition thereto, can be manufactured in a convenient way.

Accordingly, as distinct from the golf clubs of today, a club according to the present invention offers a automatic compensation of "bad" hits. Stated in other words, the ball will always stop in desired positions irrespective of whether it has been hit at a high or a low level, at the toe which moves quicker than the heel or at the heel or in some other spot . This result is achieved thanks to the fact that the grooves are arranged at a predetermined distance between themselves so that they generate different friction forces and/or in the way that the grooves exhibit a diverging or parallel extension over at least the hitting^' surface of the club blade. It is also possible, by variation of the spacing between the grooves, when the stroke is made to create different "backspins" . The design of the blade according to the ^■ invention does also involve that. that irrespective of the ball hitting point on the blade the trajectory of the ball will always be correct including its movement through the air and its rolling along the ground until it has stopped. Stated in other words, a long air passage yields a large backspin effect and a short air passage yields a small backspin effect. The final result is that the ball will always stop in the correct position, the desired distance which could be expected from a certain club.

Some preferred embodiments of the invention will now be described, reference being made to the drawing.

Fig. 1 illustrates a club blade having diverging grooves running from the toe to the heel of the club blade,

fig. 2 shows a club blade having diverging grooves which are displaced in respect of their relative positions as extending over the hitting surface of the club blade,

fig. 3 shows an alternative embodiment illustrating a club blade at which the grooves are diverging and located in the hitting surface of the blade, the distance between them being smaller lower down than higher up. The grooves diverge from the toe towards the heel,

fig. 4 shows a club blade having parallel grooves with an interdistance between them which is smaller at the lower portion of the hitting surface than at the upper portion,

fig. 5 does diagrammatically illustrate the rotation circle of a club blade upon the stroke and different hitting points on the blade at different radii,

fig. 6 is a diagrammatical view showing different travelling distances of a golf ball in response to which portion of the blade that hits the ball and to how the ball moves on the ground after the stroke which in the second case is somewhat stronger than in the first case,

fig. 7 does diagrammatically illustrate the type of back backspin rotation performed by a ball when a club blade according to the invention is used and in response to the hitting position on the blade and the lateral spreading determined by whether the hit takes place high up or lower down on the blade,

fig. 8 does diagrammatically show different ball travelling distances, where a) refers to a perfect stroke - perfect speed, b) too high speed with a hitting position low down on the blade and intensive backspin, and c) low speed - hitting position high up on the blade - small backspin.

As appears from the drawings they do show a golf club 1 comprising a shaft 3 provided with a handle portion 2 and a club blade 5 projecting from the lower portion 4 of shaft 3. Extending over the hitting surface 6 is a plurality of depressions or grooves 7 located at predetermined interspacings and exhibiting a diverging or parallel pattern over the surface 6 of club blade 5. The width and the cross-sectional profile of grooves 7 are the same in all the embodiments illustrated, along all of the hitting surface 6 and also in the longitudinal . direction of grooves 7. According to the invention the hitting surface 6 of club blade 5 may exhibit a plurality of grooves 7, the distances between them being different at the foot and at the top of the blade 5 of club 1. The grooves 7 can diverge in one direction from the toe 8 of the club blade 5 to the heel 9 of the club blade 5. Alternatively, grooves 7 may extend f om the heel 9 towards the toe 8 or at other imaginable angles.

Grooves 7 may also as an alternative diverge from the foot to the top or the other way around. Stated in other words grooves 7 may converge and/or diverge at all imaginable angles and directions. Fig. 2 illustrates combinations of various grooves 7 positioned in other patterns than those mentioned above, the grooves being displaced relatively each other in their diverging longitudinal direction.

Another alternative embodiment has been shown in fig. 3 where the grooves 7 diverge from the toe 8 towards the heel 9, the grooves 7 also being closer to each other at the foot than at the top of club blade 5.

Thanks to the positioning according to the invention of the grooves 7 with different distances between them at the foot and • at the top, as shown in figs. 3 and 4, there has been created a possibility to vary the backspin in response to whether a golf ball 10 hits at the top or at the foot. Different backspins means that the ball 10 will roll, or tends to roll, different distances backwards on the ground with which it comes into contact following its passage through the air. An arrangement' of grooves 7 closer to each other on the club blade 5 creates more backspin and, accordingly, ball 10 will pass somewhat too long through the air after having been hit by the lower portion 11 of blade 5 performing a quicker movement than the upper portion 12 and, as shown for example in fig. 5, still travel a approximately correct distance and, when the grooves 7 are less close to each other less backspin will be generated meaning that the ball 10 also in that case travels the correct distance. Consequently, thanks to the invention one can compensate the stroke distance to a correct value, corresponding to that the ball 10 is hit by the centre portion 13 irrespective of whether it does actually hit the top or the foot of blade 5. The same function is achieved disregarding whether ball 10 hits the toe 8 of blade 5 or its heel 9. Contact at the toe 8 gives the ball 10 a higher spin than at heel 9, meaning that the grooves 7 should then be located closer at the toe 8 than at the heel 9 resulting in that a hit at the toe 8 causes more backspin than a hit at heel 9. The divergence of grooves 7 at the heel 9 compensates the total length of the movement including the air travel and the ground rolling irrespective of whether ball 10 is hit by blade 5 at the toe 8 thereof or at the heel 9, the wanted correct distance being always achieved.

Consequently, as has been mentioned above, the contact point on the club blade 5 with the ball 10 will always yield a correct travelling distance of ball 10 up to the moment when it is lying still on the ground after having finished its air travel and the rolling.

In the case when the club blade 5 hits the ball 10 to high it does actually do so to late. The result of this will be that the ball 10 will deviate to the left for a right-handed player and to the right for a left-handed player. If the ball 10 hits the blade 5 too low this means at the blade 5 hits the ball 10 too early and the ball 10 will then in a logical manner deviate to the right if the player is right-handed. The explanation of this becomes obvious if one, for each of the different hitting points, places any imagined vertical plane at the right angles to the stroke direction. When the ball -10 is hit by the centre of blade 5 the direction will be correct but all other hitting points will cause a greater or smaller incorrect direction. The spread in the lateral direction can amount to as much as 7-8 metres after an air travel with our without a rolling distance, for example 175 m. The characteristic feature of the invention, diverging grooves 7, means that the backspin rotation of ball 10 will vary in response to the actual hitting point of ball 10 on club blade 5. This has been illustrated more in detail in figs. 5 and 6. A hitting point at the centre of blade 5, which also is the ideal point, yields a "straight" backspin. If the ball 10 is hit by the blade 5 to high up, the result will, due to the presence of the diverging grooves 7, become a screwed backspin causing the ball 10 to rotate to the right. Since, at a hit too high up, the vertical plane mentioned above causes the ball 10 in a normal manner to deviate to the left and the ball 10 now is in a rotation movement to the right, those two parametres will cancel each other and, finally, the ball 10 will stop at the wanted spot, namely correctly in the desired stroke direction. Conversely, if the ball 10 is hit by the blade 5 too low, it will be given it a backspin directed to the left . This does in its turn compensate away the lateral error which otherwise would have caused the ball 10 to travel too far to the right. It can consequently be said that irrespective of where on the blade 5 it contacts the ball 10 the diverging or parallel grooves 7 will compensate away all erroneous hits and the ball 10 will always reach the wanted spot. Moreover, after its air travel ball 10 will roll on the ground in its screwed backspin to the right or to the left, respectively, and still more compensate a lateral error so that the ball 10, when eventually resting still on the ground, will be found in the wanted position.

Accordingly, the final result will be that thanks to the concept according to the invention the ball 10 will reach the correct spot in both the longitudinal and the lateral direction and this irrespective of whether the club hits the ball 10 correctly, to the left, to the right, at the top or at the foot, too early or too late . This is not the case at the golf clubs today available in the market. The old concept, featuring parallel grooves with the same spacing, does accordingly not offer any compensation for bad hits be it in the longitudinal or in the lateral direction. The final position of a ball after its air travel and the rolling on the ground can thus be controlled both longitudinally and laterally in an optimal way when a golf club according to the invention is in use.

Claims

1. A golf club comprising a shaft (3) provided with a handle portion (2) and a club blade (5) projecting from it^'s lower portion (4) and, on the hitting surface (6) of the blade (5) , a plurality of scores or grooves (7) , which are located at a predetermined distance from each other and over at least the hitting surface (6) of the club blade (5) are arranged in a diverging or parallel pattern, characterized in that said grooves (7) on the hitting surface (6) of the club blade (5) are at different mutual distances, as counted from the blade bottom to its top or from its toe (8) to its heel (9) , or in the opposite direction, and do at the same time diverge from the toe (8) towards the heel (9) or from the bottom towards the top.

2. A golf club as claimed in claim 1, characterized in that said grooves (7) are arranged at a smaller mutual distance at the bottom than at the top of the club blade (5) .

3. A golf club as claimed in claim 1, characterized in that the distances between said grooves (7) are selected so as to match the wanted backspin effect .

4. A golf club as claimed in claim 1, characterized in that the distances between said grooves (7) vary in relation to the distance from the centre of a club blade (5) towards the grooves (7) .

5. A golf club as claimed in claim 1, characterized in that said grooves (7) are diverging and also arranged over the hitting surface (6) of the club blade (5) at varying mutual distances.

6. A golf club as claimed in claim 1, characterized in that the extension of each groove (7) over the hitting surface (6) of the club blade (5) is displaced relatively an adjacent groove

(7) .

7. A golf club as claimed in claim 1, characterized in that said grooves (7) extend continously and/or discontinously over the hitting surface (6) of the club blade (5) .