GB2397246A

GB2397246A - Golf putter

Info

Publication number: GB2397246A
Application number: GB0226782A
Authority: GB
Inventors: Robert Kirkwood; Andrew Kirkwood
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-11-16
Filing date: 2002-11-16
Publication date: 2004-07-21
Anticipated expiration: 2022-11-16
Also published as: GB0226782D0; GB2397246B

Abstract

A golf putter comprises a head 1 with an integral face 2, a sole 3 in the form of a backward extending flange with a flat area 13 on its underside to ensure accurate placement of the club on the putting surface, a flange 4 of similar thickness extending rearwardly from the upper edge of face 2 but only overlapping sole 3 to a limited extent in that rearward direction, and alignment marks on the upper surfaces of flange 4 and sole 3. When viewed from above, the alignment marks on both the sole 3 and the upper flange 4 form patterns determined by the relative position of the golfer's viewpoint and the clubhead.. With the clubhead correctly aligned in the desired putt direction, the golfer is able to adjust stance and therefore viewpoint until a predetermined and reproducible personal pattern appears. Preferably, the face is provided with negative loft so that with the ball point of contact above the vertical mid-point, an element of topspin is imparted by the putting stroke.

Description

GOLF PUTTER

Summary

The invention concerns a golf putter with features that are designed to help the golfer achieve greater accuracy in the direction and length of putts.

These features are: 1. A clubhead design that helps the golfer, when preparing to putt, to set the club to the ball so that it is square to the desired putt line, with accuracy and repeatability.

2. A club face design that helps the golfer, when playing a putt, to impart overspin to the ball so that rolling motion is enhanced and skidding, skipping and bobbling are minimised.

Background

It is well-documented (see, for example, John Jacobs4) that the behaviour of a golf ball after it has been struck by the club is greatly influenced by the path of the clubhead and the attitude of the club face at the moment of impact. During impact the clubhead must be moving in the direction of the target and the club face must be square to this direction if the ball is to move straight towards the target. If the club face is not square to the target direction, side spin is imparted to the ball and its path bends away from the correct direction. The inadvertent generation of side spin, causing the ball to veer off line in this way, is a common problem for golfers.

Avoiding side spin generation and, indeed, deliberately making the ball spin to control it, requires a high degree of skill.

The problem of spin and the skill needed to control it applies to all golf shots. In particular it applies to putts. Side spin affects the direction in which the ball travels after it has been struck, causing putts to miss the hole.

Whilst side spin is usually to be avoided, overspin in putts carries certain advantages and is desirable. When putts are struck in a manner that imparts overspin to the ball, and no side spin, the ball adheres better to the desired putt line. The overspin enhances the rolling motion so that the ball does not skid or skip on the putting surface and any bobbling due to imperfections in the putting surface are minimised.

This smooth rolling motion also makes it easier to judge how hard putts should be struck, so that distance accuracy is improved. Again, however, striking the ball in such a manner requires a high degree of skill.

John Jacobs, "Practical Golf", Stanley Paul & Co. Ltd. 1972.

2 Colin Montgomerie, "Playing to my strengths", Golf Monthly, July 2002, p21.

Evidently accurate putting requires: À The clubhead to be travailing in the direction of the desired putt line at the moment of impact with the ball.

À The face of the club to be square to the desired putt line at the moment of impact.

À The ball to be struck in a way that imparts overspin to it.

In addition to the above requirements correct set-up is very important when preparing to play a putt. The golfer must be able consistently to adopt a stance that produces the most successful putting results. In particular, the club must be set to the ball with its face square to the putt line. The golfer usually does this by setting the top edge of the putter face (as seen from above) square to the desired putt line but it can be shown (see Appendix 1) that this method is not reliable. Even though the top edge of the club face is perpendicular to the desired putt line, the club face may actually point in the wrong direction. Putts that are struck with the clubhead travailing in the correct direction, but with the club face incorrectly aligned, suffer side spin and tend to swerve off line.

Variability in putting set-up can also arise gradually over a period of time such that the golfer is unaware of any fault and believes that stance and set-up are correct when they are not. Putting accuracy unaccountably deteriorates. To avoid this the golfer must try to devise a routine by which set-up, stance and clubhead alignment can be checked quickly and reliably in preparation for a putt.

The invention described here is designed to: Provide a visual means by which the golfer can quickly and easily check that the set-up is correct before playing a putt so that putts are consistently struck on-line.

2 Provide a means by which overspin can be easily generated in putts so that they stay on-line and are more consistently struck to length.

According to the present invention there is provided a golf club for putting that has a head with an integral face, a sole of a certain thickness that extends backwards from the lower edge of the said face and having a flat area on its lower surface, a flange of similar thickness to the said sole that extends backwards from the upper edge of the said face to overlap a certain proportion of the said sole, an upward extension from the heel that carries a socket for attaching a shaft, and with alignment marks on the upper surface of the said flange and the upper surface of the said sole.

Description

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: À Figure 1 shows a side elevation, end elevation and plan view of the golf putter.

À Figure 2 shows typical patterns on the clubhead during set-up.

Referring to Figure 1, the clubhead (1) has a face (2) for striking the ball. An integral sole (3) extends backwards from the bottom edge of the face and a narrower flange (4) extends backwards from the top edge of the face. There is a gap, approximately equal the height of the club face, between the sole and the flange. An upward extension (5) at the heel of the club has a socket (6) for attachment to a shaft (7).

The design of the extension is such that the projected centre line of the shaft passes through the designed point of contact (8) between the club face and the ball.

A reference pattern (9) extends backwards from the top edge of the face to the rear edge of the flange on the upper surface of the flange. A corresponding pattern (10) is provided on the upper surface of the sole. Central marks (11, 12) on the upper surfaces of the flange and the sole align with the point of contact (8) on the face and all lie in a plane that is perpendicular to a flat area (13) on the lower surface of the sole. The outer edges of the lower surface of the sole are rounded to avoid interference with the putting surface when the clubhead is swung.

The club face (2) has negative loft which means that the top edge of the face (14) overhangs the bottom edge (15). The height of the face is such that when the club is properly set to the ball the point of contact (8) between club face and ball is above the ball equator (16).

It is intended that the golfer should follow a calibration procedure with the invented putter in which the combined patterns on the flange and sole are observed and a "personal parallax pattern" or "P3" is identified. This is the pattern observed by the golfer when the putter is set squarely to the ball and the golfer's stance is correct. It depends on the relative position of the golfer's eye(s) with respect to the clubhead, and the attitude of the clubhead. Typical patterns are shown in Figure 2.

The calibration procedure is done using a flat horizontal putting surface on which a straight line is marked to represent the desired putt line. The golfer sets the putter to a ball sitting on this line, with the flat area of the sole (13) resting on the surface and the centre marks (11, 12) parallel to the putt line and aligned with the centre of the ball. The club is now accurately set, square to the line of the putt. Keeping the club in this position, the golfer takes a normal (habitual) grip and adopts a normal (habitual) putting stance. The golfer then observes the flange pattern (9) and its alignment with the sole pattern (10). The appearance of this alignment pattern constitutes the golfer's personal parallax pattern (P3). It must be memorised and recalled during play.

To play any putt, the golfer selects the desired putt line and sets the putter to the ball with the sole flat on the putting surface. The centre reference line (10) on the flange is then set parallel to the putt line and aligned with the centre of the ball. The golfer adopts a normal (habitual) grip and stance as before, and mentally compares the observed alignment patterns on flange and sole with the P3 alignment. The attitude of the clubhead is adjusted until the alignment pattern is identical to P3. The club face is now pointing in the correct direction and if the club is swung along a line parallel to the reference marks (10, 11) the club face will be square to the putt line at impact.

With the club correctly set to the ball, when the golfer makes a normal putting stroke the negative loft of the club face ensures that the ball is struck above its equator. It can be shown (see Appendix 2) that this imparts overspin to the ball, and provided the club face is square to the putt line, no side spin will be generated.

Thus the club design enables the golfer to check the set-up quickly and reliably when preparing to putt, and to impart overspin, and enhanced rolling motion, to the ball when playing the putt. Variability in the direction and length of putts is minimised and putting accuracy increased.

Appendix 1 (Refer to Figure A1) Figure A1 (a) shows a view onto the face of the club when set flat and square to the putt line, and also when tilted. Figure A1 (b) shows a side view onto the toe of the club when set flat and square to the line of the putt and in contact with the ball.

Figure A1 (c) shows a similar view when the club is tilted. Figure A1 (d) and A1 (e) show plan views of the club when flat and in contact with the ball, and when tilted in contact with the ball.

In Figures A1 (d) and A1 (e) horizontal sections through the point of contact with the ball are shown. In Figure A1 (e), the horizontal section cuts the toe of the tilted club near the lower edge where the thickness is small, and cuts the heel of the club where the thickness is greater. The line where this section cuts the club face is no longer perpendicular to the putt line, even though the top and bottom edges of the club face remain perpendicular to the putt line.

G

Appendix 2 (Refer to Figure A2) Consider the club face, with negative loft, to be travailing in a horizontal direction when it strikes the ball. During contact the ball is compressed over a small area.

Because the clubhead momentum is horizontal, the force that the clubhead exerts on the ball will also be horizontal.

Now consider the clubhead to be composed of horizontal rod-like filaments. Those filaments within the compressed area have their length compressed by a small amount, the amount depending on the position of the filament in the flattened area.

We can calculate the force needed to compress a filament in terms of its original length, its compressed length and the elastic constant (Young's modulus) for the material of the ball. This is the force exerted on the filament by the club face.

First we calculate the amount by which the filament s shortened and divide it by the original length of the filament. This ratio is called the filamentary strain. We multiply the strain by Young's modulus to get the compressive stress in the filament, and then by the cross sectional area of the filament to get the force necessary to produce the compression. We assume this to be equal to the force exerted on the filament by the small area of the club face in contact with it.

If we then multiply the filamentary force by the perpendicular distance of the filament from the centre of the ball, we obtain the couple exerted on the ball by the small club face area at the filament. We repeat these steps for every filament in the compressed area.

Two points are noteworthy: 1. Each filamentary force can be replaced by an equal force through the centre of the ball and its corresponding couple about the centre. By adding these forces and couples for all the filaments we can get the total horizontal force acting through the centre of the ball by the club face, and the total couple about the centre of the ball.

2. Each filamentary couple can be split into two components, one trying to produce over or under spin and the other trying to produce side spin, depending on the position of the filament within the compressed area. If the club face is square to its line of travel, the compressed area of the ball will be symmetrical about a plane through the line of travel, the centre of the ball and the point of contact of the ball with the putting surface. The side spin couples cancel. By observation we can see that horizontal filaments above the ball equator exceed those beneath it, so that the clockwise (overspin) couples exceed the anticlockwise (back-spin) couples. The sum of the couples is one that tends to produce overspin. This can be shown to be true mathematically.

We conclude that overspin and enhanced rolling motion can be achieved in a normal putting stroke when the putter face has negative loft.

Claims

Claims 1. A golf club for putting that has a head with an integral face,

a sole of a certain thickness that extends backwards from the lower edge of the said face and having a flat area on its lower surface, a flange of similar thickness to the said sole that extends backwards from the upper edge of the said face to overlap a certain proportion of the said sole, an upward extension from the heel that carries a socket for attaching a shaft, and with alignment marks on the upper surface of the said flange and the upper surface of the said sole.
2. A golf club as claimed in Claim 1 with a head and integral face such that the upper edge of the face overhangs the lower edge thus constituting negative loft, the height of the face being a certain value such that when the clubhead is moved essentially parallel to the putting surface to make a putting stroke, the point of contact between the club face and the ball is above the ball equator.
3. A golf club as claimed in Claims 1 and 2 with a flat area machined on the lower surface of the said sole that acts as a reference surface for other parameters in the clubhead.
4. A golf club as claimed in Claims 1, 2 and 3 with a shaft attached to the said socket such that the projected centre line of the shaft passes through the point on the club face that is essentially the point of contact with the ball when a normal putting stroke is made.
5. A golf club as claimed in Claims 1 through 4 in which the said alignment marks on the said flange and sole form patterns when viewed from above that are affected by parallax when the clubhead or the view point, or both, are moved, the said patterns to be used as visual evidence that the clubhead is accurately set-up to the ball in preparation for making a putting stroke.
6. A golf club as claimed in Claims 1 through 5 that is designed to be used in accordance with the rules of golf.