GB1597526A - Golf clubs - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO GOLF CLUBS (71) I, FRANCIS LAMBERT ROBSON, a British Subject, and New Zealand Citizen, of 131 Koutu Road, Rotorua, New Zealand, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to golf clubs and has particular application to putters.

Conventional putters suffer from the disadvantage that a slight twist of the putter shaft during the putting stroke will cause the putter head to twist from its proper position of having its flat striking face at right angles to the intended line of travel of the ball and consequently the ball will be deflected from the intended line of travel. By way of example, it is believed that a twist of about 3 of the flat striking face of a conventional putter about the shaft would be sufficient for the ball to completely miss the hole on a putt of 1 metre. Similarly a twist of about 2 of such a putter would probably prevent the ball from falling within the hole unless its speed was sufficiently exact to stop the ball on the lip of the hole.

Hitherto, putters have been provided with the shaft entering the head at a fixed angle or lie. Conventional putters have relatively small heads and the lie of the shaft is determined by drilling a hole into the head at a predetermined angle. As the lie of the shaft, whether right handed, left handed, or at a particular angle to the vertical, is important to a player's performance, top tournament players have their putters made to their individual requirements involving the drilling of a hole into the putter head at the angle most suited to that player's stance. On the other hand, putters available to the general public are usually manufactured in three standard lies.It will be appreciated that whilst it is less expensive to produce production runs of three different putters than it is to individually drill putter heads to suit a particular player, it is not generally possible to obtain a good putting stance with a commercially available putter.

It is an object of this invention to go some way towards overcoming the above mentioned problems in providing a putter which minimises the effect of twist of the putter head on the resulting shot, or which will at least provide the public with a useful choice.

Accordingly, the invention provides a putter comprising a head having an outwardly curved striking face, the radius of curvature of a central region of the face being such that the effect, on striking a ball, of twisting a shaft of the putter in either direction about the shaft axis by up to a given angle determined by half the angle subtended by the central region at its centre of curvature is minimised.

In order that the invention may be readily understood, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is a top plan view of a preferred putter head; FIGURE 2 is a front elevation of the putter head of Figure 1, viewed on arrow A; FIGURE 3 is a side elevation of the putter head of Figure 1, viewed on arrow B; FIGURE 4 is a detailed plan view showing the development of the putter face curvature; FIGURE 5 illustrates a plan view of a putter head having provision for shaft adjustment; FIGURE 6 illustrates a rear view of the putter head of Figure 5, (along arrow A); FIGURE 7 illustrates an exploded side elevation of the putter head of Figure 5.

A preferred putter head 10 has a striking portion 11 and a rear portion 12. As is best seen from figure 1, the preferred putter head is relatively deep (i.e. from striking portion to rear protrusion) with the depth being slightly less than the width.

The striking portion 11 has a front striking face 13 and side faces 14, 15. The rear portion 12 has a convex rearwardly facing protrusion 1 2a contiguous with concave sides 12b 12c conjoined with the side faces 14, 15.

The upper face 20 of the putter head has a shaft entry 21 at or adjacent the centre line C-C. The shaft entry can be formed at any desired angle.

The bottom face 22 may be curved as desired to minimise scuffing of the putter on the green. The putter head may be made of any convenient material, although it is preferred that the putter head 10 is formed of a resilient material. For example the putter head may be formed of nylon or other suitable plastics material. In the case of nylon, it is desirable to load the head, for example by positioning weights 23, 24 within the head. Conveniently, the weights may be formed of a high density material such as lead. The weights 23, 24 may have a cylindrical portion 25 and a downwardly depending pintle 26 with the dimensions of the cylindri cal portion being varied to vary the weight required for a particular head. By providing downwardly depending pintles on the weights. it is possible to position the weights within a mould, and to mould the plastics material around the weights.

Sighting means 30 may be provided on rear portion 12. Conveniently, this can take the form of a disc coloured white or some other readily visible colour to assist a golfer to keep aware of the swing line of the putter.

This disc can be of equivalent size to the diameter of a golf ball for convenient sight ing. The striking portion of the putter head has an outwardly curved (i.e. convex) strik ing face 13. The curvature of the striking face is best seen in top plan view of figure 1 and in the plan view of figure 4. An additional sighting zone 36 may be provided above the striking face leading to a striking face leading to a straight edge 37 to provide a sighting edge for golfers used to sighting on the straight edge of a flat faced putter.

Apart from the curvature of the striking face, the striking face 13 may be inclined rearwardly with respect to the vertical to provide a degree of loft. The degree of loft is shown by angles X in figure 3. A suitable amount of loft for this putter would be X=3 , although it will be appreciated that this figure is given by way of example only.

The degree of curvature of the striking face can be modified to take into account the permissable angle of twist of the putter head.

By way of example, I have found that on a putt of 48 inches, with a hole 44 inches diameter a 2 '1 twist either side of normal on a flat faced putter will produce lines of ball travel which are tangents to the edge of the 441 inch diameter hole, with the ball thereby grazing the edge of the hole.

The illustrated putter has been designed to minimise the effect of twist of the putter head and to this end I have designed a curved striking face based on a permissable degree of twist of y either side of normal. Turning now to figure 4, line R1, corresponds to the centre line of the head, whilst R2 and R3 are radii drawn at angles y to the centre line.

Line T, is tangent to line R1, whilst lines T2, T3 are tangent to radii R2, R3, respectively. It will be evident that T2 and T3 intersect line T, at angles y. R4 is a radius drawn to an outlying portion of the curved face. Other tangents drawn to radii between R2 and R3 have been omitted for the purpose of clarification. However, it will be appreciated that the medial portion of the curve (between R2 and R3) has a corresponding bundle of tangents.

If the line of swing coincides with centre line R, of the striking face, the ball will follow the line of swing as it will be hit by the centre of the curved striking face corresponding to tangent T1. This would be equivalent to hitting the ball "square-on" with a flat faced putter.

If the head is twisted through y" so that the line of swing corresponds to line R2 then the ball will still follow the line of swing as it will be hit by that portion of the striking face corresponding to tangent T2. Similarly, if the head is twisted in the other direction so that R3 corresponds to the swing line of the striking face corresponding to tangent T3. In the light of the above example, it is preferred that y=2:", allowing the putter head to minimise the effect of twist on striking a ball.

With this angle of permissable twist, it is preferred that the outlying portions of the curved striking face (e.g. corresponding to R4), are of a lesser degree of curvature than the medial portion (i.e. corresponding to R2-R1-R3). This is by no means essential however, as the striking face may be formed from a simple curve rather than a developed curve.

It will be appreciated that conventional putters are of relatively small size compared to the putter illustrated in figure 5. Conventional putters have a relatively shallow head, that is to say the distance between the striking face and the rear face is only slightly larger than the diameter of the shaft; with the shaft being inserted towards one end of the head.

The putter illustrated in figure 5 has a much greater distance between the striking face and the rear most portion of the putter than is the case with a conventional putter.

This putter head is substantially the same as that shown in figures 1 to 4, with the exception of the shaft mounting; conse quently features common to both putter heads will not be repeated in describing the embodiment shown in figures 5 to 7.

Putter head 50 has a striking face 51 and a rear protrusion 52. This putter head has an upper face 53 in which an elongate slot 54 is provided. As shown, this slot is disposed symmetrically with respect to centre line 59 of the putter head, with the major axis of the slot extending at right angles to centre line 59. This elongate slot 54 extends downwardly into the putter head to near the bottom of the putter head but does not extend completely therethrough (see figure 7).

A cavity 55 provided within the head intersects with the slot 54. Conveniently, this cavity is in the form of an aperture which extends through the rearward protrusion of the putter head about the centre line 59 and extends slightly beyond the slot 54. The rear protrusion is provided with a substantially flat abutment face 64. Holding means 56 is designed to fit within cavity 55.

Preferably, the holding means consists of a cylindrical tube or boss movable within cavity 55. Conveniently, the holding means 56 has a hole 57 extending therethrough at right angles to the major axis of the holding means and disposed adjacent the inner end of the holding means so as to be aligned with slot 54, when the holding means is positioned within cavity 55. Preferably, the holding means is provided with adjustment means to position the holding means in aperture 55 with respect to the slot 54. Conveniently, this is provided by a threaded portion 60 on the outer end of the holding means and a nut 61 adapted to fit onto the threaded portion 60, and contact the abutment face 64.

The putter head can be assembled on a shaft 62 as follows. Shaft 62 is positioned in slot 54 with holding means 56 such that shaft 62 can pass down through the slot 54 and through the hole 57. The desired angle of the shaft with respect to the putter head can then be determined for a particular player and the shaft aligned by moving the shaft relative to the putter head and thereby causing the holding means 56 to rotate about its central axis. The shaft and putter head are then held in place relative to one another and the nut 61 is screwed onto the holding means to press against abutment face 64, and thereby move the holding means with respect to the aperture and thus pull the shaft 62 into tight engagement against the rearward face 66 of the slot 54.By so clamping the shaft with respect to the slot and the holding means, it is possible to fix the shaft at a predetermined angle with respect to the putter head. The shaft may then be locked permanently in place, if necessary, by suitable means, e.g. by use of a locking nut, or the use of an adhesive thread locking compound between the holding means and the nut.

It will be appreciated with the available angle of the shaft with respect to the putter head can be determined by the length of the slot 54. Figure 6 shows a variation of a degrees either side of vertical. This may for example be about 22 either side of vertical as this has been found to accommodate the variations required by different players. It will be appreciated that this angular variation is by no means essential to the invention and that wider variation can be provided if desired.

The putter head is preferably formed of a suitable plastics material, for example, nylon, together with suitable ballast, e.g. lead weights, as has been described above. By this means, it is possible to provide a putter head of desirable characteristics and yet provide a sufficient depth between the striking face and the rear face to allow for provision of the holding means of this invention.

It will be appreciated that whilst the provision of shaft adjustment has particular application to the relatively deep putter head with curved striking face shown in figure 5, it also has application to shapes other than that illustrated. For example, the putter head could substantially triangular when viewed in plan with a striking face and a rearward protrusion formed by the apex of the triangle. In which case the portion of the rear face could be undercut to provide an abutment face for the nut or the like. Indeed the nut could be replaced by some other adjustment such that the holding means can be moved relative to the slot to clamp the shaft in place.

Finally, it will be appreciated that the different aspects of this invention have been described by way of example only and that various alterations or modifications may be made to the foregoing without departing from the scope of this invention as set forth

Claims (17)

in the claims. WHAT I CLAIM IS:

1. A putter comprising a head having an outwardly curved striking face, the radius of curvature of a central region of the face being such that the effect, on striking a ball, of twisting a shaft of the putter in either direction about the shaft axis by up to a given angle determined by half the angle subtended by the central region at its centre of curvature is minimised.

2. A putter as claimed in claim 1, wherein the given angle is substantially 2+ in either direction.

3. A putter as claimed in claim 1 or 2, wherein the outwardly curved striking face is a developed curve having a medial portion of greater curvature than outlying peripheral portions.

4. A putter as claim in claim 1, 2 or 3, wherein an upper portion of the head is provided with a sighting edge.

5. A putter as claimed in any preceding claim wherein the striking face is inclined rearwardly to provide loft.

6. A putter as claimed in any preceding claim wherein the head has a rearwardly facing protrusion with sighting means thereon.

7. A putter as claimed in any one of claims 1 to 5, wherein the head has a striking portion including the striking face; a rearwardly facing protrusion contiguous with the striking portion; the rearwardly facing pro trusion having a convex portion and being conjoined to the striking portion by concave side walls; and a mounting aperture for a shaft in an upper portion of said head.

8. A putter as claimed in any preceding claim wherein the head is formed of a plastics material.

9. A putter as claimed in claim 8, wherein the plastics material is nylon.

10. A putter as claimed in any preceding claim wherein the head is weighted.

11. A putter as claimed in claim 10, wherein a pair of substantially cylindrical metal weights are provided within the head.

12. A putter as claimed in claim 11, wherein the metal weights have a downwardly depending pintle portion of reduced cross section.

13. A putter as claimed in any preceding claim having a shaft receiving slot in an upper portion thereof, and holding means within said head to hold a shaft at a desired angle with respect to the head.

14. A putter as claimed in claim 13, wherein the head is provided with a holding cavity intersecting said slot.

15. A putter as claimed in claim 13 or 14, wherein the holding means includes a body member having a shaft receiving hole therein, and wherein the body member can be moved relative to the slot to lock a shaft in tight engagement with a side of the slot, and in a released position the body member can pivot to allow adjustment of shaft lie.

16. A putter as claimed in claim 15 wherein the body member is in the form of a tube and is provided with a screw-thread and a nut, said nut abutting against a portion of said head to enable said tubular member to be moved with respect to said slot.

17. A putter substantially as herein described with reference to the accompanying drawings.