WO2008085021A2

WO2008085021A2 - Golf club

Info

Publication number: WO2008085021A2
Application number: PCT/NL2007/000300
Authority: WO
Inventors: Karel Nieuwenhuijsen
Original assignee: Karel Nieuwenhuijsen
Priority date: 2006-12-05
Filing date: 2007-12-05
Publication date: 2008-07-17
Also published as: WO2008085021A3

Abstract

A golf club for putting has a clubhead (11) and a shaft (12), the clubhead having a striking face (15) for moving a ball on impact. The striking face has a curvature for, in address position of the clubhead, controlling the movement of the ball on impact when striking. The curvature may have a vertical curvature (16) arranged, in address position of the clubhead, vertically along the striking face from a sole (13) of the clubhead to a top side (14) of the clubhead, and/or a horizontal curvature (17) arranged, in address position of the clubhead, horizontally along the striking face from a heel of the clubhead near a player to a toe of the clubhead away from the player. The vertical curvature (16) provides top-spin, while the horizontal curvature (17) compensates an arc-shaped trajectory of the clubhead due to the swinging movement of the player's arms.

Description

GOLF CLUB

FIELD OF THE INVENTION

The invention relates to a golf club, in particular a putter, the golf club having a clubhead and a shaft, the clubhead having a striking face for moving a ball on impact. Golf is a well-known sport where a golf ball is moved towards a hole using dedicated golf clubs.

BACKGROUND OF THE INVENTION

Golf clubs are known in various forms. A distinction may be made with respect to the use in a respective phase or circumstances of playing the ball, usually called woods, irons and putters. The final shots are taken on a field near the hole called a putting green. The golf clubs dedicated for use on the putting green are called putters.

The book "Decisions on the Rules of Golf 2004-2005; by the R&A Rules Limited and the United States Golf Association; ISBN 0 600 60894 8", in particular the Appendix II, pages 516-523 thereof, describes the shapes and requirements for golf clubs for being allowed in the official game of golf. In particular the nature and shape of the club head of a putter are extensively described.

Putters are used for playing the ball near the hole, and require a high degree of precision and control for the direction of moving the ball at relatively low speeds. However, a problem of the known putters is that precise control of the movement of the ball is difficult.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a putter that has improved control of the movement of the ball.

For this purpose, according to a first aspect of the invention, the golf club as defined in the opening paragraph is characterized in that the striking face has a curvature for, in address position of the clubhead, controlling the movement of the ball on impact when striking. The curvature has the following effect. Traditionally the putter has a straight striking face, and the player will try to swing the putter so as to move the striking face along an imaginary straight line in the direction of the hole. The intention is to have the point of impact on the ball in line with the imaginary line. On impact the ball start moving in a direction along a line to the actual point of impact and the centre of gravity of the ball, i.e. the centre of a spherical symmetric ball. Due to resistance of the ground surface of the green the ball will also rotate when moving. The curvature of the striking face allows controlling and optimizing the point of impact on the ball so as to have the ball moving along the imaginary line the player has in mind. Hence, advantageously, the curved striking face allows modifying the point of impact on the ball with respect to a straight striking face when putting.

In an embodiment of the golf club the curvature comprises a vertical curvature arranged, in address position of the clubhead, vertically along the striking face from a sole of the clubhead to a top side of the clubhead. The vertical curvature allows controlling the height of the point of impact on the ball. In particular, the height of the point of impact may be controlled to be above the centre of the ball, which causes a top spin, i.e. the top side of the ball moves forward faster than the bottom side of the ball.

The invention is also based on the following recognition. During putting the ball. will be moved in a trajectory along the ground surface. Necessarily the ball will spin. The inventor has seen that by immediately providing a top spin on impact with the striking face the top spin will depend less on the actual ground surface conditions, which will differ randomly. Hence a more reliable control of the direction and spin of the ball is achieved by the top spin on impact. Moreover, by providing a slightly vertically curved striking face, the player may intentionally hit the ball a little higher for achieving some additional top spin.

In an embodiment of the golf club the curvature comprises a horizontal curvature arranged, in address position of the clubhead, horizontally along the striking face from a heel of the clubhead near a player to a toe of the clubhead away from the player. The horizontal curvature allows controlling the line of movement due to the point of impact on the ball. In practice, due to a slight horizontal curve of the striking face, the actual line of movement of the ball corresponds to the imaginary line.

The invention is also based on the following recognition. During putting the golf club is moved by the player along a substantially straight line corresponding to the imaginary straight line in the direction of the hole. However, the inventor has seen that, in practice, whereas the player has the intention to move the clubhead along the imaginary straight line, the actual movement of the clubhead follows an arc due to the fact that the player swings the golf club while his/her feet on the ground provide a fixed centre point. The radius of the arc may be around the effective length of the arms of the player and the length of the shaft when projected on the ground surface. The player may, probably subconsciously, try to compensate and straighten the arc. Nevertheless, the inventor has found in practice, the movement of the clubhead is not a straight line but along an arc. When the ball is hit early or late in the arc, the straight surface will have an angle with respect to the imaginary line. The combined misjudgment of the player with respect to the presence of the arc in combination with the early of late hit results in a deviation of the ball with respect to the imaginary line towards the hole. Misjudgments of the average player resulting in a deviation due to the arc may correlate with the point of impact in horizontal direction between the heel and toe of the striking surface. Furthermore, a prolonged contact between ball and striking face may effectively result in a deviation due to the arc. Surprisingly, the inventor has found that the horizontal curvature of the striking surface compensates various combined effects and misjudgments of the player.

In an embodiment of the golf club, the curvature comprises a vertical curvature arranged, in address position of the clubhead, vertically along the striking face from a sole of the clubhead to a top side of the clubhead, and a horizontal curvature arranged, in address position of the clubhead, horizontally along the striking face from a heel of the clubhead near a player to a toe of the clubhead away from the player. The combination of the vertical and horizontal curvature surprisingly improves the control of the player on the movement of the ball when putting.

In an embodiment of the golf club, the vertical curvature comprises a substantially circular vertical segment. In general it is noted that the vertical curvature may have any suitable shape, e.g. elliptical or a-spherical. However, a substantially circular, spherical, vertical segment provides a suitable control of the top spin of the ball.

In an embodiment of the golf club, the horizontal curvature comprises a substantially circular horizontal segment. In general it is noted that the horizontal curvature may have any suitable shape, e.g. elliptical or parabolic. However, a substantially circular, spherical, horizontal segment appears to correctly compensate the misjudgment of the average player while putting. Further preferred embodiments of the golf club according to the invention are given in the appended claims, disclosure of which is incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will be apparent from and elucidated further with reference to the embodiments described by way of example in the following description and with reference to the accompanying drawings, in which Figure 1 shows golf club for putting,

Figure 2 shows a front view of a clubhead for putting,

Figure 3 shows a side view of a clubhead for putting,

Figure 4 shows a top view of a clubhead for putting,

Figure 5 shows a side view of a clubhead with striking face having a vertical curvature, and

Figure 6 shows a top view of a clubhead with striking face having a horizontal curvature. Corresponding elements in different Figures may have identical reference numerals.

DETAILED DESCRIPTION OF EMBODIMENTS

Figure 1 shows golf club for putting. Figure 1 shows a 3-dimensional view of the golf club and a ball 10. The golf club has a clubhead 11 attached to a shaft 12. The shaft as such is well-known, and may be provided with a grip on the top and to be held by the player. The clubhead 11 has a striking face 15 for hitting a ball 10. The golf club is depicted in the normal position to hit the ball 10, which is usually called the address position. Further Figures also show the clubhead oriented according to the address position.

The clubhead is provided with a curvature at the striking face. The curvature may include a vertical curvature 16 as indicated by arrows, and/or a horizontal curvature 17 as indicated by further arrows. The curvature improves the control when putting the ball as elucidated below.

Figure 2 shows a front view of a clubhead for putting. The top side 14 of the clubhead may be substantially flat and the bottom side, usually called sole 13, may also be flat, or slightly curved as shown in Figure 2. The shaft 12 is curved towards the player to facilitate the putting. The shaft may be removably fixed to allow remounting for left and right handed use. In the horizontal plane the end of the striking face near the player is called the heel 22 and the end of the striking face 15 away from the player is called the toe 21. Figure 3 shows a side view of a clubhead for putting. The height 31 from top side 14 of the clubhead may to the sole 13, may be around 40 mm, i.e. substantially equal to the diameter of the ball. In the horizontal plane the back end 32 opposite to the striking face may have an arbitrary shape. The material may extend backwards as far as the common rules of the game of golf allow, e.g. a total depth of around 110 mm using a striking face width of 115 mm.

The clubhead shown in Figure 3 is provided with a vertical curvature 16 as indicated by arrows. The vertical curvature allows hitting the ball above its center of gravity, which results in top spin. The vertical curvature 16 may be slightly curved in an arbitrary pattern, e.g. elliptical. Due to the vertical curvature the golf ball will always start with topspin. This moves the ball in a straight line from the moment of impact. The ball starts direct with a rolling speed and it follows a straight line from the beginning.

In an embodiment the vertical curvature has a substantially circular vertical segment. The segment is shown with respect to a straight dash-dotted line 33. The radius of the substantially circular vertical segment may be any value between 1 cm and 10m. In practice a value between 0.04 m and 1 m appeared to be very effective, and a value around 12 cm proved to optimal.

In an embodiment the substantially circular vertical segment has a centre between 2 cm and 1 m above the sole of the clubhead. It is noted that the centre of the segment may be around the middle of the height of the striking face. However, the centre may also be put higher, e.g. around the top 14, or even higher above and outside the clubhead. This position has the effect that the striking face tends to face downwards, and thereby the point of impact on the ball is higher, resulting in additional top spin. Figure 4 shows a top view of a clubhead for putting. The striking face 15 of the clubhead may be around 150 mm wide as indicated by arrows 40. In the horizontal plane the back end 32 opposite to the striking face may have lobes 41 , and/or the sides of the clubhead may have indents 42. The material may be shaped in order to increase the inertia, which prevents the clubhead from rotating when the ball is hit off-centre. A center line 43 indicates the center of gravity with respect to the striking face 15

The clubhead shown in Figure 4 is provided with a horizontal curvature 17 as indicated by arrows. The horizontal curvature 17 allows hitting the ball at a straight line via its center of gravity and the hole, which improves directional control while putting.

In practice various explanations for the improved control may apply in dependence of circumstances. In general the movement of the golfer's arms is not accurate for moving the clubhead in a straight line. The current golf club will correct these movements through the horizontal curvature of the striking face of the clubhead. The ball will always follow the direction of the putting line, because the club face is always in a transverse position with the putting line. The result is that the ball will leave in a straight line with the putting line. An example based on misjudgment of the player with respect to early or late hits of the ball has been given in the introductory part. Furthermore, during a prolonged contact between ball and clubhead, the clubhead may follow an arc due to the player swinging the golf club from a fixed standing position. Due to the arc the clubhead deviates slightly from the intended straight line, and during impact the point of contact on the striking face may shift towards the toe of the clubhead. The shift of the point of impact results in a small arc of impact along the horizontal curvature of the striking face. Assuming that the radius of the horizontal curvature (i.e. the small arc) roughly corresponds to the radius of the arc (i.e. the involuntary arc in the player's swing), the force of the striking face will remain oriented in the direction of the hole.

The horizontal curvature 17 may be slightly curved in an arbitrary pattern, e.g. elliptical or hyperbolical. In an embodiment the horizontal curvature has a substantially circular vertical segment. A circular segment is shown with respect to a straight dash-dotted line 44. The radius of the substantially circular horizontal segment may be any value between 10 cm and 100m. In practice a value between 0.25 m and 5 m appeared to be very effective, and a value around 1 m proved to optimal.

Figure 5 shows a side view of a clubhead with striking face having a vertical curvature. The striking face has a vertical curvature 16 as indicated by arrows. The vertical direction according to the normal address position is indicated by line 51. In the embodiment the vertical curvature has a central part 53 that is only slightly curved, e.g. having a large radius or even substantially flat. Furthermore, an upper curved segment is provided having an average upper radius, whereas a lower curved segment is provided having an average lower radius. The upper radius and the lower radius may be selected independently as appropriate for achieving the required amount of spin, in dependence of practical circumstances, materials used for the surface of the golf club, and preferences of the players. A practical value for the upper and low radius is between 0.1 and 0.2 m.

Figure 6 shows a top view of a clubhead with striking face having a horizontal curvature. The striking face has a horizontal curvature 17 as indicated by arrows. In the embodiment the horizontal curvature has a central part 60 that is only slightly curved, e.g. having a large radius, or even substantially flat. Furthermore, a toe side curved segment 61 is provided having an average toe angle, whereas a heel side curved segment 62 is provided having an average heel angle. The toe angle and the heel angle may be selected independently as appropriate for achieving the required control of the putting direction, in dependence of practical circumstances, materials used for the surface of the golf club, and preferences of the players. A practical value for the toe and heel angles is around 3 degrees.

In an embodiment the striking face 15 is provided with both curvatures as follows. The striking face may have a vertical curvature 16 as shown in Figure 3 and a horizontal curvature as shown in Figure 4, the combination being shown in Figure 1.

In an embodiment the golf club has a second striking face. The striking face may have a curvature as described above, or may be a traditional straight striking face. Currently the rules of golf require a putter having two similar striking faces, e.g. for right-handed and left-handed use. However, different faces, e.g. having different curvatures, may be advantageously applied as well.

A practical prototype for the putter has been manufactured and tested. The technical data are as follows. The weight of the components of the putter is: shaft 123 gram, grip: 72 gram and club head: 308 gram, the total weight is 503 gram. The grip is based on a standard grip with a flat side. The shaft is made of steel, which provide a stiff shaft. The shaft angles at 20 degrees towards the player at approximately 40 mm above the club head. The length is approximately 860 mm. The shaft does not lean forwards nor backwards, and is attached in the middle of the club head. The club head material is beech wood. The height of the clubface from top to sole is 40 mm; the depth of the clubface from striking face to back end is 145 mm, and the width of the club head from toe to heel is 150 mm. Although the invention has been explained mainly by embodiments of a golf club for putting, the same curvature may be applied to any golf club or stick for a similar game in which a ball is to be hit to be moved with high precision. Furthermore, the precise dimensions of the face and clubhead may be varied in practice as required to achieve the effects as elucidated above.

It is noted, that in this document the word 'comprising' does not exclude the presence of other elements or steps than those listed and the word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements, that any reference signs do not limit the scope of the claims, that the invention may be implemented by means of any type or combination of material, including metal, wood, rubber or plastic, and that several 'means' may be represented by the same item of hardware. Further, the invention is not limited to the embodiments, and lies in each and every novel feature or combination of features described above.

Claims

1. Golf club for putting, the golf club having a clubhead (11 ) and a shaft (12), the clubhead having a striking face (15) for moving a ball (10) on impact, characterized in that the striking face has a curvature (16,17) for, in address position of the clubhead, controlling the movement of the ball on impact when striking.

2. Golf club as claimed in claim 1 , wherein the curvature comprises a vertical curvature (16) arranged, in address position of the clubhead, vertically along the striking face (15) from a sole (13) of the clubhead to a top side (14) of the clubhead.

3. Golf club as claimed in claim 1 , wherein the curvature comprises a horizontal curvature (17) arranged, in address position of the clubhead, horizontally along the striking face from a heel (22) of the clubhead near a player to a toe (21) of the clubhead away from the player.

4. Golf club as claimed in claim 1 , wherein the curvature comprises a vertical curvature (16) arranged, in address position of the clubhead, vertically along the striking face from a sole (13) of the clubhead to a top side (14) of the clubhead, and a horizontal curvature (17) arranged, in address position of the clubhead, horizontally along the striking face from a heel (22) of the clubhead near a player to a toe (21) of the clubhead away from the player.

5. Golf club as claimed in claim 2 or 4, wherein the vertical curvature comprises a substantially circular vertical segment (35).

6. Golf club as claimed in claim 5, wherein the substantially circular vertical segment (35) has a radius between 0.04 m and 1 m.

7. Golf club as claimed in claim 5, wherein the substantially circular vertical segment (35) has a centre between 0.02 m and 1 m above the sole of the clubhead.

8. Golf club as claimed in claim 3 or 4, wherein the horizontal curvature comprises a substantially circular horizontal segment (45).

9. Golf club as claimed in claim 8, wherein the substantially circular horizontal segment (45) has a radius between 0.25 m and 5 m.

10. Golf club as claimed in claim 1 , wherein the clubhead has a second striking face opposite to the striking face, the second striking face having a curvature as defined for the striking face in any of the claims 1 to 9.