AU2001100301A4 - Improvements relating to golf clubs - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

SPECIFICATION

INNOVATION

PATENT

Invention Title: Improvements relating to golf clubs The following statement is a full description of this invention, including the best method of performing it known to us: Freehills Carter Smith Beadle Melbourne\003882934 Printed 21 August 2001 (17:22) page 2 IMPROVEMENTS RELATING TO GOLF CLUBS This invention relates to the manufacture of sporting articles for use in ball sports, particularly golf clubs and the like.

The popularity of golf as a sport and recreation has increased significantly over recent years, and golfers and other sportsmen are continually looking for developments in equipment which can improve their performance in their chosen sport. New technology has led to many recent improvements in the design and manufacture of golf clubs. For instance, traditional wooden shafts have given way to metal and graphite, and the heads of woods and irons are now manufactured from different metals, such as titanium, and have seen several changes in their shape and weight distribution.

Golf putters have also experienced various changes in their design and manufacture, including the incorporation of polymer inserts into the face of the putter to provide a softer feel. However, a principal factor in the design of a successful putter is its balance.

Various manufacturers of putters have realised that every putter has a natural "hang"; that is if the putter shaft is balanced at two points spaced apart along its length, the head of the putter will naturally hang at a particular angle to the vertical.

For example, the PING (registered trade mark) putter manufactured by the Karsten Manufacturing Company has a "hang" of approximately 450 to the vertical. Other manufacturers have produced putters which, when balanced at two spaced points along the length of the shaft, naturally occupy a position in which the plane of the striking face of the putter is substantially horizontal. This type of putter is called "face balanced".

Putters which have a natural hang, however, suffer from the disadvantage in use that if the golfer putts with a relaxed grip, the head of the putter has a tendency to turn or pivot about the longitudinal axis of the shaft which will usually result in a "pulled" or "pushed" missed putt. While this tendency may be overridden by the golfer, this requires the golfer to use a firmer grip which will adversely affect the "feel" of a putt.

Melbourne\003876820 Printed 17 August 2001 (16:14) 2 There have previously been attempts to provide a truly balanced putter. U.S.

Patent No. 5,228,332 (Bernhardt) discloses a golf putter which has a shaft with a substantially straight handle portion and a substantially straight neck portion attached to the head, the neck portion being at an inclined angle to the handle portion. The method of manufacturing the golf putter disclosed in U.S. 5, 228,332 involves determining the front and rear and end to end centre of gravity cutting planes for the putter head, establishing the point of attachment of the neck portion to the putter head based on the locations of the centre of gravity cutting planes, and turning the putter head and shaft relative to each other in order to make adjustments which are said to achieve "true balance" for the putter.

Whilst a putter manufactured by the method of U.S. 5,228,332 may be balanced about the two horizontal centre of gravity cutting planes of the putter head, such a putter is not truly balanced about the longitudinal axis of the substantially straight handle portion of the shaft because it has a natural "hang" in which the club face of occupies a substantially vertical orientation when balanced at two points spaced apart along the length of the shaft of the putter. Such a putter may be said to have a "positive" balance, rather than "true" balance.

It is desirable to provide a sporting article having a head attached to a shaft, and more particularly a golf club, with improved balance which does not suffer from the tendency of the head to turn or pivot relative to the shaft when the club is swung with a relaxed grip.

It is also desirable to provide a method of manufacturing such a sporting article with improved balance.

According to one aspect of the invention, there is provided a sporting article comprising an elongate shaft having a substantially straight handle portion at a first end and a head provided on a second end of the shaft, wherein when the article is rotatably supported at a first point at said one end of the shaft on the central longitudinal axis of the handle portion of the shaft and a second point along the length of the handle portion such that the article is freely rotatable about the central longitudinal axis of the handle portion, the article is able to balance with its head in Melbourne\003876820 Printed 17 August 2001 (16:14) 3 any orientation and does not rotate to a position of natural hang.

According to another aspect of the invention, there is provided a method of manufacturing a sporting article comprising the steps of: providing an elongate shaft having a handle portion at a first end and a second end remote from the handle portion; providing a head for the article; attaching the second end of the shaft to the head; rotatably supporting the article at a first point on the central longitudinal axis of the handle portion at said first end of the shaft, and at a second point disposed along the length of the handle portion so that the article is freely rotatable about the central longitudinal axis of the handle portion; and if the head rotates to a position of natural hang, adjusting the attachment of the shaft to the head and/or the mass distribution of the head until the article is able to balance on said first and second points with its head in any orientation such that the head does not have a position of natural hang.

A sporting article in accordance with the invention is preferably a golf club, and more preferably a golf putter.

A golf club with no natural hang in accordance with the invention may have a shaft which is substantially straight along its entire length from the handle portion at the first end of the shaft to the second end of the shaft which is attached to the club head.

When a golf club having substantially straight shaft is balanced in accordance with the invention such that it does not have a natural hang, it is believed that the centre of gravity of the club head lies precisely on the central longitudinal axis of the straight shaft.

In an alternative embodiment in accordance with the present invention, the shaft of the golf club has a substantially straight handle portion and a bent neck portion adjacent to its point of attachment to the head at the second end. In this case, it has been realised that the head and/or shaft must be adjusted during manufacture such that the combined centre of gravity of the head and neck portion Melbourne\003876820 Printed 17 August 2001 (16:14) 4 is arranged to lie precisely on the central longitudinal axis of the main elongate shaft portion and handle portion.

Preferably, the golf club is a putter having an elongate head. In one preferred embodiment, the head of the putter is substantially symmetrical about a vertical plane extending through its centre of gravity and has striking surfaces on both its major side faces. Such a putter with striking surfaces on both its major side faces may be used by either a right handed or left handed golfer.

Preferably, the lower surface or sole of the putter head is rounded and is narrower than the other surface of the putter head so that a golfer is less likely to "stub" the surface of the putting green with the sole of the club when executing a putt.

The centre of gravity of the putter head is preferably spaced from the lowest point of the sole of the putter by a distance which is substantially the same as the radius of a golf ball. This assists the golfer in imparting a degree of top spin to the ball when executing a putting stroke. This promotes better ball roll and a ball struck with such a putter is less likely to "skip" on the putting surface before commencing its roll.

The present invention will now be described in greater detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side view of a first embodiment of a golf putter in accordance with the invention; Figure 2 is a cross-sectional view of the head of the putter in Figure 1; Figure 3 is a plan view of the head of the putter of Figure 1; Figure 4 is a side view of a second embodiment of a golf putter in accordance with the invention; Figure 5 is an end view of the head of the putter of Figure 4; Figure 6 is a plan view of the head of the putter of Figure 4; Figure 7 is a side view of a device for testing the balance of a golf club; Figure 8 is an end view of the device of Figure 7; Figure 9 is a side view of the device of Figure 7 used to test a face balanced Melbourne\003876820 Printed 17 August 2001 (16:14) putter; Figure 10 is a section on the line X X of Figure 9; Figure 11 is a side view of the device of Figure 7 testing a positive balanced putter; Figure 12 is a section on the line XII XII of Figure 11; Figure 13 is a side view of the device of Figure 7 testing a "heel-toe weighted putter"; Figure 14 is a section on the line XIV of Figure 13; Figure 15 is a side view of the device of Figure 7 testing a "reality balanced" putter in accordance with the invention; Figure 16 is a schematic view similar to Figures 10, 12 and 14 illustrating the testing of a putter in accordance with the invention which may balance in any orientation on the device of Figure 7; Figure 17 is a sectional view through the head of a putter in accordance with the invention next to a golf ball; Figure 18 is a sectional view of the putter head of Figure 17 striking a golf ball to impart top spin to the golf ball; Figure 19 is a sectional view through a prior art putter striking a golf ball to impart under spin to the golf ball; Figure 20 is a schematic perspective view of a prior art putter striking a golf ball in a putting stroke; and Figure 21 is a schematic perspective view of a putter in accordance with the invention striking a golf ball in a putting stroke.

The putter 1 shown in Figure 1 comprises a elongate shaft 10 having a handle portion 12 at first end 11 and a putter head 20 attached to a second end 13 of the shaft 10. A grip 14 is provided on the handle portion 12.

As shown in Figure 1, the shaft is substantially straight and is of circular cross-section. The shaft 10 may be a cylindrical tube of uniform cross-section.

Alternatively, the shaft may be slightly tapered with its handle portion 12 having a wider diameter than the end 13 which is attached to the putter head 20. The shaft Melbourne\003876820 Printed 17 August 2001 (16:14) 6 may be made of metal such as steel, or any other convenient material, such as graphite. The grip 14 is preferably formed from a relatively soft material, such as a natural or synthetic rubber material. The grip 14 may be circular in cross section, but preferably is of non-uniform cross-section having a flat surface 15 on one side extending perpendicularly to a flat side face 21 of the putter head 20 which forms the striking surface of the putter. The grip 14 has a central recess 16 in its end surface 17 at the first end 11 of the putter.

The putter head 20 as shown in Figures 1 to 3 is of oblong form having two flat major side surfaces 21, 22, upper and lower surfaces 23, 24, and front and rear ends 25, 26. The end 25, 26 of the putter head are generally rounded as shown in Figures 1 and 3. The lower surface 24 of the head is also rounded, and the putter head as shown in the cross-sectional view of Figure 2 has tapered lower sides surfaces 27, 28 leading to the rounded lower surface 24 so as to form a cambered sole.

The putter head 20 has a centre of gravity C, and is substantially symmetrical about longitudinal and lateral vertical planes A and B which extend through the centre of gravity C. The head also has a horizontal plane D passing through its centre of gravity C.

As shown in Figures 17 and 18, the distance from the lowest point of the lower surface 24 to the horizontal plane D passing through the centre of gravity is substantially the same as the radius of a golf ball 30. This assists the golfer in striking a golf ball at a level substantially at or slightly above the centre 32 of the golf ball so as to impart a degree of top spin to the ball 30 when putting. A ball struck with top spin starts rolling sooner, and is more likely to drop in the hole when it reaches the end of its travel at the rim of the hole. The top spin imparted by a putter in accordance with the invention is illustrated in Figure 18.

Figure 19 illustrates the adverse effect of a putter head 40 having a low centre of gravity 42 striking a golf ball 30. When the putter 40 strikes the golf ball it has a tendency to lift the golf ball 30 off the putting surface 34 which causes the golf ball to "skip" before it starts rolling. When the putter 40 strikes the golf Melbourne\003876820 Printed 17 August 2001 (16:14) 7 ball 30, it also has a tendency to impart back or under spin to the golf ball as illustrated by the arrows in Figure 19. Further, a putter with a sharp front lower edge 44 leads to a greater tendency for the golfer to stub the lower edge 44 on the putting surface 34 when executing a putting stroke, in contrast to the putter of the present invention with its cambered sole 24.

As shown in Figure 1, the putter head 20 is attached to the shaft 10 with the central longitudinal axis S at the shaft 10 extending at an acute angle to the vertical, as is conventional in most putters.

The putter of Figures 1 to 3 differs from conventional putters in that it is manufactured so that the central longitudinal axis S of the shaft 10 passes precisely through the centre of gravity C of the head 20. In conventional putters, the centre of gravity of the putter head is offset in one direction or another from the central longitudinal axis of the handle portion of the elongate shaft. This results in the head of conventional putters having a natural position of "hang" when the shaft of the putter is balanced on two points spaced apart along the axis of the shaft. In contrast to conventional putters, a putter in accordance with the invention has no natural position of hang, and is said to be "reality balanced".

Referring to Figures 7 and 8, there is shown a simple device 70 for testing the balance of putters, which also assists in manufacturing a putter in accordance with the invention.

The device 70 of Figures 7 and 8 comprises an elongate member 71 having a handle attachment portion 72 at one end and a shaft support portion 73 at its opposite end. The handle attachment portion 72 extends generally perpendicularly from said one end of the elongate member 71 and has a screw 74 extending through an aperture in the attachment portion 72. At one end of the screw 74, there is a metal loop 75 which forms a manually engageable member for rotating the screw 74. The screw 74 also extends through plastic washers 76, 77 on opposite sides of the handle attachment portion 72.

The shaft support portion 73 extends from the opposite end of the elongate member and has a curved end surface 78 between two prongs 79 that is adapted to Melbourne\003876820 Printed 17 August 2001 (16:14) 8 support the shaft of a golf club in such a manner as to allow the shaft to rotate freely about its longitudinal axis.

Figures 9 to 16 show the device of Figure 7 and 8 in use for balancing a variety of different putters. In each case, the screw 74 is inserted into the recess 16 in the end surface 17 of the putter grip 14, and the shaft 10 is placed in the curved end surface 78 of the shaft support portion 73. The manually engageable loop 75 is used to lightly tighten the screw 74 to an extent such that the putter is rotatably supported at a first point on the longitudinal axis of the shaft 10 at the first end 11 of the grip 14, and at a longitudinally spaced apart point by the shaft support portion 73 at the other end of the grip 14.

Figures 9 and 10 show a face balanced putter 90 rotatably supported by the device 70. As shown particularly in Figure 10, a face balanced putter automatically rotates into a position in which the striking surface 91 of the putter head 92 lies in a substantially horizontal plane. This is because the centre of gravity C is offset from the central longitudinal axis S of the shaft, and the weight of the putter head is evenly distributed on either side of a vertical plane P passing through the axis S and the centre of gravity C.

Referring to Figures 11 and 12, there is shown a "positive balanced" putter rotatably supported on the device 70 in similar manner to that of Figures 9 and and corresponding reference numerals have been applied to corresponding parts.

The positive balanced putter 100 shown in Figures 11 and 12 automatically rotates to a position of natural hang such that the ball striking surface 101 of the putter head 102 lies in a vertical plane extending through the central longitudinal axis of the shaft S and the centre of gravity C of the putter head 102 as shown in Figure 12. This is achieved by having the centre of gravity C of the putter head 102 offset from the axis S and the weight of the putter head 102 evenly distributed on either side of the longitudinal plane P extending through the axis S and the centre of gravity C. As shown in Figure 12, a positive balanced putter may have ball striking surfaces 101 and 103 on the front and rear major side faces of the putter head 102.

Melbourne\003876820 Printed 17 August 2001 (16:14) 9 Referring to Figure 13, there is shown a heel toe weighted putter 130 rotatably balanced on the device 70, and corresponding reference numerals have been applied to corresponding parts. As shown in Figure 13, the putter 130 has a bent shaft portion 134 at the lower end of the main shaft portion 10 and attached to the putter 132. The heel-toe weighted putter 130 has a natural hang position in which the striking face 131 extends at an angle of approximately 45 0 to a vertical plane passing through the central longitudinal axis S of the shaft and the centre of gravity C of the putter head 132.

Figures 15 and 16 show the device 70 used in the manufacture and testing of a putter 1 in accordance with the invention. The putter 1 is initially manufactured with the putter head 20 attached to the shaft 10 such that the centre of gravity C of the putter head lies approximately on the central longitudinal axis S of the shaft However, owing to manufacturing tolerances, it can be very difficult to initially arrange for the centre of gravity C to lie exactly on the shaft axis S so that it is balanced in accordance with the invention.

In order to test the balance of the putter 1, the screw 74 of the handle attachment portion 72 is screwed into the small recess 16 in the top surface 11 of the putter grip 14 by the manually engageable member 75, and the main portion of the shaft 10 below the grip 14 is balanced in the part-circular recess 78 in the shaft support portion 73 so that the shaft is freely rotatable about the central longitudinal axis S of the shaft 10. The recess 16 in the upper surface 17 of the grip 14 lies on the central longitudinal axis S of the shaft 10. Thus, when the putter 1 supported on the device 70 is perfectly balanced in accordance with the invention with the centre of gravity C lying exactly on the central longitudinal axis S of the shaft the putter head will have no natural plane of "hang" and may be balanced at any one of an infinite number of positions with the plane of its striking surface 21 occupying any angle relative to the vertical plane P passing through the central longitudinal axis S of the shaft 10 as shown in Figure 16.

If, however, the putter 1 is not perfectly balanced in accordance with the invention, the centre of gravity C will be slightly offset from the central longitudinal Melbourne\003876820 Printed 17 August 2001 (16:14) axis S of the shaft 10, and so the putter head 20 will rotate when supported on the device 70 to a position of natural hang in which the plane of its striking surface 21 is at a particular angle relative to the vertical plane P. In this case, the manufacturer of the putter must make adjustments, either to the attachment of the putter shaft to the putter head 20 and/or to the weight distribution of the putter head 20 so that the centre of gravity C is located precisely on the central longitudinal axis S of the shaft Referring to Figures 20 and 21, there is shown the beneficial effect of a putter balanced in accordance with the present invention during a putting stroke, as opposed to a heel-toe weighted putter or a face balanced putter.

As shown in Figure 20, when a heel-toe weighted putter 130 is swung in a pendulum action with a relaxed grip, the striking face 131 of the putter head 132 is at an angle to the target line T of the putt which is the direction in which the shaft of the putter 130 moves during the putting stroke. Therefore, as the striking surface 131 is open at the point of impact, the actual line on which the ball travels after impact is at an angle to the target line T. This results in a missed putt which appears as though the golfer has pushed the putt to the right, whereas it is the natural hang of the heel-toe weighted putter which has resulted in the missed putt.

As shown in Figure 21, when a putter 1 in accordance with the invention is swung with a pendulum action along the target line T, there is no natural tendency for the striking surface 21 of the putter head 20 to either open or close, and so the plane of the striking surface 21 remains perpendicular to the target line T regardless of whether the putter 1 is swung with a firm or relaxed grip, so that the actual line on which the golf ball 30 travels is the target line T.

In order to assist the golfer in striking the golf ball 30 at the "sweet spot" on the striking surface 21 which is substantially in front of the centre of gravity C, a guide mark or groove 29 may be provided on the upper surface 23 of the putter head substantially above the centre of gravity C.

It is also possible to simulate a putt with a relaxed grip using the device 70 of Figures 7 and 8 in the following manner.

Melbourne\003876820 Printed 17 August 2001 (16:14) 11 If the handle attachment portion 72 of the device 70 is attached by the screw 74 to the upper surface 17 of the putter grip 14, and the shaft 10 is rested on the shaft support portion 73 with the elongate member 71 extending in a vertical plane, a putting action with a relaxed grip can be simulated by holding the elongate member 71 instead of the actual grip 14 of the putter. When the putter is swung in a pendulum action holding the elongate member 71, the putter head of a heel-toe weighted putter or a face balanced putter will rotate relative to the central longitudinal axis S of the shaft 10 such that the putter head 92, 132 either "opens" or "closes" relative to the target line T. However, when a putter in accordance with the invention is swung using the device 70, the putter head 20 does not rotate relative to the central longitudinal axis S of the shaft 10 so that the plane of the striking surface 21 of the putter head 20 is maintained perpendicularly to the target line T.

Figures 4 to 6 of the drawings show a modified embodiment of a putter 50 in accordance with the invention. The putter 50 is similar to the putter 1 of Figures 1 to 3 and corresponding reference numerals have been applied to corresponding parts. Thus, the putter 50 has an elongate shaft 10 having a handle portion 12 at one end on which a grip 14 is provided.

The putter 50 of Figures 4 to 6 differs from that of Figures 1 to 3 in that the shaft 10 has a lower straight main portion 51 and a bent lower neck portion 52 which is attached to the putter head 20. Thus, the lower part of the neck portion 52 attached to the head 20 extends at an angle to the central longitudinal axis S of the main portion 51 and handle portion 12 of the shaft The putter head 60 of Figures 4 to 6 is generally similar in shape to the putter head 20 of Figures 1 to 3. However, because of the bent neck portion 52, a putter head with its centre of gravity C lying on the central longitudinal axis S of the main shaft portion 51 and handle portion 12, will not be balanced so that it has no natural position of "hang".

It has been realised in the present invention that in order to make a "reality balanced" putter which has no natural position of hang when balanced on a device Melbourne\003876820 Printed 17 August 2001 (16:14) 12 such as that of Figures 7 and 8, the combined centre of gravity G of the putter head and the lower shaft portion 52 must be arranged to lie on the central longitudinal axis S of the main shaft portion 51 and handle portion 12 of the shaft It will therefore be appreciated that the centre of gravity C of the head 60 of the "reality balanced" putter 50 will actually be offset from the central longitudinal axis S of the shaft 10 in order to counteract the bent neck portion 52 of the shaft as shown in Figures 4 and 6.

The putter of the embodiment of Figures 4 to 6 may be manufactured in accordance with a similar method to that described with reference to Figures 1 to 3.

In this case, the neck portion 52 of the shaft 10 is attached to the putter head 60 in such a manner that the centre of gravity C of the head 60 is slightly offset from the central longitudinal axis S of the straight main portion 51 of the shaft 10, the golf club is rotatably on a device such as that of Figure 7 and 8, and subsequently adjustments are made to the angle of attachment of the neck portion 52 of the shaft to the head and/or the mass distribution of the head 60 until the combined centre of gravity G of the head 60 and neck portion 52 lies precisely on the central longitudinal axis S of the main shaft portion 51. This results in a putter which has no natural position of hang and whose putter head 60 may occupy any orientation when balanced on the device 70 of Figures 7 and 8.

A preferred material for a putter head 20, 60 of a putter in accordance with the invention is brass because it is renowned for providing a satisfactory weight and feel for putters, and also it is malleable and convenient to machine in order to alter its weight distribution and shape. Such a putter head can be manufactured from a base block of brass repetitively until it has the correct weight distribution when attached to a shaft to provide a putter which has no natural hang. It is, however, envisaged that when a satisfactory design of putter with no natural hang has been achieved, such a putter design may be mass produced, e.g. in a metal sand-casting process, although when such a cast head is attached to a putter shaft, hand finishing of the putter head is likely to be required to produce a putter which has no natural position of hang in accordance with the present invention.

Melbourne\003876820 Printed 17 August 2001 (16:14) 13 It will be appreciate that various modifications may be made to putters in accordance with the invention as described above without departing from the scope and spirit of the present invention. For instance, the putter shaft may have neck portions of different shapes and orientations, provided the weight distribution of the putter head and/or the attachment of the putter head to the shaft is adjusted during manufacture so that the combined centre gravity of the putter head and neck portion is arranged to lie precisely on the central longitudinal axis S passing through the main shaft and handle portion to produce a putter which has no natural hang when balanced on a device such as that of Figures 7 and 8.

Further, whilst the embodiments described with reference to Figures 1 to 3 and Figures 4 to 6 have a vertical axis of symmetry and striking faces 21 and 22 on opposite sides, it is possible for putters that have no natural hang in accordance with the invention to be manufactured in other putter designs, such as "flanged back" and "mallet-style" putters. It is also possible for putters in accordance with the invention to include face inserts of polymer or other materials, provided the weight distribution of the material of the putter head on the opposite side of the centre of gravity is adjusted accordingly to produce a putter which has no natural hang.

Melbourne\003876820 Printed 17 August 2001 (16:14) 14

Claims (5)

1. A sporting article comprising an elongate shaft having a substantially straight handle portion at a first end and a head provided on a second end of the shaft, wherein when the shaft is rotatably supported at a first point at the first end of the shaft on the central longitudinal axis of the handle portion and a second point along the length of the handle portion such that the article is freely rotatable about the central longitudinal axis of the handle portion, the article is able to balance with its head in any orientation and does not rotate to a position of natural hang.

2. A sporting article according to claim 1 wherein the sporting article is a golf club having a shaft which is substantially straight along its entire length from the handle portion at the first end of the shaft to the second end which is attached to the club head.

3. A sporting article according to claim 1 wherein the sporting article is a golf club and the shaft has a substantially straight elongate handle portion and a bent neck portion attached to the head.

4. A sporting article according to claim 2 or claim 3 wherein the golf club is a putter and the centre of gravity of the putter head is spaced from the lowest point of the sole of the putter head by a distance which is substantially the same as the radius of a golf ball.

5. A method of manufacturing a sporting article comprising the steps of: providing an elongate shaft having a handle portion at a first end and a second end remote from the handle portion; providing a head for the sporting article; attaching the second end of the shaft to the head; rotatably supporting the article at a first point on the central longitudinal axis of the handle portion at the first end of the shaft and at a second point along the length of the handle portion such that the article is freely rotatable about the central longitudinal axis of the handle portion; and if the head rotates to a position of natural hang, adjusting the attachment of the shaft to the head and/or the mass distribution of the head until the article is able Melbourne\003876820 Printed 17 August 2001 (16:14) to balance on said first and second points with its head in any orientation such that the head does not have a position of natural hang. Melbourne\003876820 Printed 17 August 2001 (16:14) 16