Field of the Invention

This invention relates to golf clubs.

Background of the Invention

All golf clubs are limited in their design, to conform with the rules laid down by the governing body of golf, the "Royal and Ancient" (R&A). The requirements of a putter head are a weighted object and a flat surface to strike the ball.

When putting, the golfer has four main aims: (i) that his eye should be over the top of the ball; (ii) that the face of the putter should be normal to the line in which the ball is to be hit; (iii) that he should hit "through the ball"; and (iv) that he should hit the ball with the so-called "sweet spot", of the putter.

Putters having a line or other mark, to indicate the "sweet spot", are known. However, such marks do not allow the golfer to meet all the given aims.

In order to ensure that a putt is successful and is holed on a flat surface, there are essentially only two requirements. One is that the ball must be travelling at the correct velocity to drop into the hole, and the other is that the putter face must strike the ball adjacent to the line of putt that joins the centres of the hole and the ball. There is only one point on a golf ball where the putter face can strike the ball to propel the ball on its intended line (described herein as "the critical point"). The area where the putter must strike is less than 1.5 mm in width if the putt is to be successful over a distance of only 1.2 metres. A player can line up the putter so it indicates this critical point and in so doing have the face square to the intended line.

Another problem faced by the golfer is when the ball is up against the fringe grass just off the putting surface. In this case, club players and PGA professionals tend not to use the putter, because of the resistance presented by the grass.

One option is a lofted wedge. This provides less grass resistance than a putter. It is used to strike the ball exactly at its equator with the sharp leading edge of the wedge. The difficulty in this is the wedge has a rounded leading edge and must meet the ball exactly in the centre of the edge, or the ball will travel at an angel to the selected line across the green; not to mention the difficulty of striking the ball at its equator.

A second option is a fairway wood/metal. These clubs are difficult to use due to the length of the shaft. They are designed to strike the ball vast distances from the fairway. They also have a rounded face and, if the contact is not central on the face, the ball will not travel on the selected line across the green.

The most common head weight for a putter, found by player's preference, is around 335 grams. Depending on the material used in the manufacture, this limits where the mass of weight is located. In most good quality putters, the material used is stainless steel. This has a density of around 7.5 grams/cm ³ . Consequently, for a head weight of 335 grams, the volume of the head must be 44.66 cm ³ .

Most putters have a face length of around 1 1-12 cm. The face depth is around 2.5 cm. Given these parameters, the width must be only 1.556 cm to get the volume required.

If the putter head is made as one straight length, with the dimensions above, the weight will be distributed along its entire length. However, the ball- contacting area, conducted through field trials, is only around 3 cm of the putter face. In other words, the area of contact when the ball is struck is only 26% of the putter face/weight. The bulk of the mass (74%) is not directly behind the ball impact area. To overcome this, the bulk of the weight is typically placed at the ends of the putter face; this is known as periphery weighting.

The face loft, on most good putters, is set at 4 degrees from upright. This is good for putting on the green as it promotes the hands leading the putting stroke. If the face is vertical and the player's hands lead the stroke, the ball is likely to be driven partially into the ground. This would reduce the forward momentum of the ball and reduce the required travel to the hole. If the hands lag the head in the stroke, due to the length of the sole sitting inline with the ground, it will lift the face away from the ball and be struck by the underside of the putter.

Summary of the Invention

One aspect of the present invention is based in part on the realisation that, in addition to the aims given above, two further points also hold true. One is that the putter head does not have to be travelling on the line of the putt, providing the face contacts the critical point on the ball. The other is that, if the putter head is travelling on the line of the putt and the putter face is only 1.5 degrees open, or closed to that line, the ball will miss the hole over a distance of 2 metres. That is because it is impossible for the putter face to make contact at the critical point on the ball. Accordingly, a player need only (A) determine the critical point on the back of the golf ball in relation to the line, and (B) ensure that the putter, irrespective of the putter head line, strikes the critical point. It should be borne in mind that the critical point is less than the width of a dimple on the golf ball at a range of 1 metre or more.

Further, it has been appreciated that, instead of trying to ensure that the face of the putter is normal to the intended line, a different approach can be used. In this approach, the player simply look down at a pointer and aim at the back of the hole. If a ball was placed in front of this pointer it would indicate the critical point on the ball. Also if this pointer was on the putter head the face would be exactly 90 degrees to that line.

According to a first aspect of the present invention, a golf putter has, on the top side of the club head, extending normal to its face, an area contrasting appearance defining an arrow lying along the line of putt. Whereas known putters may include a thin line, the novel putter has as its characteristics an area that is sufficiently striking to cause the golfer to concentrate on that area only.

A putter of the invention is designed to assist the player to fulfil both A and B of the above requirements. This is due to an indication pointer located on the putter head.

The process of putting requires a set procedure:

Select an imaginary line the ball must travel on when it is struck (achieved by reading the green)

Place the putter face at 90 degrees to this imaginary line.

Take the putter back away from the ball, then return the face at 90 degrees through the balls location where it was at address.

The only point on a golf ball that must be contacted to propel it on a given line is adjacent to the selected line through the ball. With an indicator situated on top of the putter head at 90 degrees to the face, the face must be square to the selected line when the indicator is aimed through the ball.

On a flat green, for ease of explanation, with no borrows, using a putter of the invention, the procedure is different, as follows;

Aim the indicator directly through the ball at the hole. The face is automatically 90 degrees square to the hole; not an imaginary line and the indicator is pointing exactly at the critical point on the ball.

The contrast in colour of the indicator and the head of the putter will give the player "Residual Vision" when the head is taken back. This makes it easier to return the putter to the position it was at address.

The indicator also offers other advantages. If it is assumed that the player has assessed there is 300 mm borrow on the putt. The putter can be aimed directly at the hole, then rotated slightly to aim off 300 mm, to allow for borrow.

The face angle of the putter at impact cannot be emphasised enough

(laws of motion, the ball will travel 100% adjacent to the point of contact with the ball). If the putter face is only 1 degree open or closed, the ball will miss the hole over a distance of 2.5 metres. When the indicator on a putter of the invention is aligned so that it is pointing directly at the hole, the face is automatically normal to the line.

As can be seen in Fig. 1 , it is easier to point the indicator at the hole than trying to square the putter face to an imaginary line. Field trials were conducted using this method. The users' comments verify the ease of using this technique, i.e. by using the indicator.

An advantage of this invention is that, once the putter is in the correct position, a caddy could look along through the indicator and confirm this to be the case. The player can then use this indicator to move the putter away directly on that line with confidence. Another advantage is that, if the putt is on a side hill slope and requires borrow of, say 300 mm to the left, the indicator is aimed 300 mm to the left of the hole.

A second aspect of the invention, instead of shying away from the problem of choosing a putter or a wedge, tackles it head on. In particular, this aspect of the invention appreciates that a reason for this problem is that the fringe grass creates resistance in the back and through swing of the putter. The reason for this resistance is the putter's leading face and back edge catching the grass. By eliminating the reason for squaring the face to the line, it is possible to reduce the length of the face and cut down on resistance through the grass. The degree of cut-away can be 5 to 30%, relative to the case in which the base of the face is parallel to the ground.

Field trials indicate that only 20% of the face is used to strike the ball. Therefore, by removing a portion of the lower part of the face, resistance is reduced when putting from the fringe. Since not all the putter face is used to strike the golf ball, the novel putter minimises or avoids the area that is not of any use. However, the player must have confidence when looking down at the putter, ensuring there is sufficient area to hit the ball. The answer is to keep the top view of the face the same and reduce the area not required, thus reducing the effect of grass. If only 20% of the face is removed at the bottom, this will reduce the resistance of the grass by 65-70%.

Fig. 2 shows the actual impact area of a golf ball striking the face of a putter. The putter has the smallest available length face (outlined in black). This clearly demonstrates the redundant area of the face, even on a putter with a small face length.

According to a third aspect of the invention, a golf putter has a head that is made of different materials, wherein one material is relatively dense and constitutes the core of the head, including the ball-contacting face, and another material is relatively less dense and constitutes the periphery of the head. The materials are, for example, stainless steel and a synthetic resin, respectively. By means of the present invention, it is possible to provide 80% mass directly behind the ball impact zone and increase the head volume to 100 cm ³ .

Fig. 3 shows that, internally, 80% of the mass is directly behind the impact zone. This provides what may be called a "hammer" effect, as it gives the most consistent strike to the ball over the whole of the impact zone. To achieve this, weighting is made of stainless steel and placed directly behind the impact zone; density 7.5 g/cm ³ . The remainder of the head is manufactured from a specially formulated synthetic resin with a density of only 1 .03 g/cm ³ . The stainless steel accounts for 80% of the weight and the resin for only 20% of the weight. More generally, the proportions of relatively dense material (e.g. 4 to 15 g/cm ³ ) and relatively less dense material (e.g. 0.5 to 2 g/cm ³ ) may be from 40:60 to 90:10.

In use of other putters, the impact feel diminishes as the ball is struck further away from the centre of the face, due to weight distribution.

By rounding as much as possible the leading edge of the face, resistance can be cut down. Now by rounding the back edge of the sole, further resistance can effectively be eliminated.

Fig. 4 shows that the leading and back edges of the face and sole have been rounded to reduce further grass resistance.

According to a fourth aspect of the invention, a golf putter has a base that is at an angle to the ground when the putter is held upright, whereby lying the base on the ground provides increased loft on the face of the putter.

Playing from the fringe grass would be greatly assisted if the putter face had more loft than 4 degrees. This problem has been overcome by sweeping the putter body upwards from front to back.

If the player, when playing from the fringe grass, allowed the putter head to lead the hands it would increase the face loft, thus lifting the ball from the grass. The angle between ground and base may be 5 to 20°; the loft may be similar, e.g. 5 to 25°.

The invention is described herein by way of example only with reference to the accompanying drawings. Fig. 1 is partial cross-sectional top view of a golf ball and of the head of a putter embodying the present invention. The drawings are not necessarily to scale.

Fig. 1 shows a golf ball 1 , a putter having a handle 2 (shown in cross- section), a blade 3 and also a member 4 extending normal to the face of the blade. The top of the member 4 and part of the top of the blade 3 define an arrow-shaped area 5 whole apex 6 is at the face of the blade 3. The area 5 is in visual contrast to the remainder of the top at least of the club.

In use, a golfer can easily line up the apex 6 with the centre of the golf ball 1 , with his eye over the top of the ball. The area 5 provides clearly visible directional aid, so that the blade hits the ball normal to the desired line of travel. The golfer can readily ensure that, by keeping the area 5 and apex 6 in line with the centre of the golf ball 1 , the putter hits through the ball. Further, provided that the area 5 is aligned with the correct parts of the blade, the golfer can also ensure that the ball is hit on the "sweet spot" of the putter. It will thus be apparent that all the four aims identified above are met, very simply, in use of a putter of the invention.

Perhaps more importantly, in use of a putter of this invention, the pointer on the putter can be placed directly behind the ball, pointing through the centre towards the hole. The pointer is now indicating both the line and critical point on the ball. Further, since the line to the hole is still indicated while the player is looking down at the ball, focus can now be given more to the point of contact between putter and ball (the critical point).

The indicating area which is the primary feature of the present invention may be formed of any suitable material. It may be cast as part of the putter head, and be coloured, e.g. yellow, for good contrast with a typical grey metallic head.

The contrasting area may be formed on a member that is somewhat proud of, level with, or recessed with respect to the top of the putter head. It is the top view that is important, minimising the problem that a golfer has by virtue that his eye cannot be in a line with the ball and the hole.

With respect to known putters, a putter of the invention provides the golfer with greater confidence of success in putting. In particular, it may achieve one, more or all of:

1. The easiest way to square the putter face to a selected line of ball travel

2. The best way of increasing the consistency of stroke, across the largest ball impact area

3. How to enable the putter to be played from the fringe grass

4. How to reduce any grass resistance when playing from the fringe grass

5. How to enable a player to use the putter and increase the face loft when the ball is just in the fringe grass

6. How to part the fringe grass on the back stroke to eliminate grass resistance 7. How to reduce resistance caused by the putter face when playing from the fringe grass on the forward stroke.

8. How to locate 80% of the putter weight to be directly behind the ball impact area.

9. How to combine all of the above and still conform to the rulings of the R&A.

By laying the head back, it is possible to increase the face loft to lift the ball from the fringe grass. This is shown in Fig. 5.

In order to minimise further grass resistance on the backward movement of the putter head, it is shaped to part the grass. Coupled with the upward sweep at the back end of the body, grass resistance is reduced even more. As can be seen in Fig. 6, by making the back end of the putter body pointed, its design is to cut through the grass on the back swing when used in the fringe grass.