WO2005089884A1

WO2005089884A1 - Head for a golf club

Info

Publication number: WO2005089884A1
Application number: PCT/GB2005/001000
Authority: WO
Inventors: Douglas Boyd Buchanan
Original assignee: Topsport Golf Bv
Priority date: 2004-03-16
Filing date: 2005-03-16
Publication date: 2005-09-29
Also published as: GB0620517D0; GB2427827A; GB2412070A; GB2427827B; GB0405916D0

Abstract

A head (10) for a golf club is provided. The head (10) has the shape of an inverted isosceles triangle. The vertex (18) of the triangle provides a natural aiming point for the golfer. The head includes a thin plate (924) forming the striking face (21) which is plain and has no upper flange as in conventional cavity back irons. A thin rear flange (25) extends from the bottom of the striking face to a large bulbous flange (28) which assists the follow through movement. Heel and toe supporting side flanges are provided but stop short of the upper rim so that it remains plain. The apex or vertex (18) of the isosceles triangle occurs approximately one third in from the toe which moves the centre of gravity towards the heel.

Description

HEAD FOR A GOLF CLUB

This invention relates to a head for a golf club. More particularly, the invention is concerned primarily with a head for golf clubs of the iron type but the invention could be applied to putters and other specialized clubs such as driving irons. Golf clubs known as cavity back irons or so-called "Game improvement clubs" have been known for some time. More recently, there has been a development wherein the cavity back head is provided with an undercut channel. A problem with this design is that in order to accommodate the undercut channel a relatively large mass of material must be provided at the bottom of the club head.

JP-A-2002/272886 discloses a cavity back putter which is symmetrical in both plan and elevation.

EP-A-0608069 discloses a typical cavity back iron with rearwardly extending upper flange portion. It is also conventional in that the toe is higher than the heel. According to the present invention, there is provided a head for a golf club, the head having a heel portion and a toe portion, a lower flanged sole portion extending between the heel portion and the toe portion and an upper edge portion, the upper edge portion being plain and free of any rearwardly extending flange portion, the head including a striking face and a hosel wherein the head is in the form substantially of an isosceles triangle, the vertex of the triangle being adjacent the centre-line of the striking face thereby being displaced from the toe and on the side of the head opposite the sole portion, whereby the centre of gravity of the head is displaced towards the heel.

The invention will now be described by way of example only with reference to the undemoted drawings wherein:

Figure 1 is a frontal view of a golf club head in accordance with the invention. Figure 2 is an end view of the head shown in Figure 1. Figure 3 is a perspective view looking on the front face of the head. Figure 4 is a sectional view taken through the vertex of the head. Figure 5 is a perspective view looking on the rear of the head. Figure 6 is a sectional view on a horizontal plane A - A through the head . In Figure 1 there is shown a frontal view of a head 10 in accordance with the invention . Head 10 has a heel portion 11, a toe portion 12 and a lower sole portion 13 extending between the heel portion 11 and toe 12 . The sole portion 13 is relieved

5 slightly at 14 and 15 which assists in making a clean strike. Head 10 includes a hosel

16. From Figure 1 it can be seen head 10 has a top or upper edge portion 17 and is shaped generally or substantially in the form of an isosceles triangle having a vertex 18 with sole portion 13 being on the opposite side of head 10 to vertex 18 and with vertex 18 being adjacent to the centre-line 19 approximately bisecting the length g of sole portion 13 . Vertex 18 forms a natural aiming point when the player addresses a ball thus contributing to the accuracy of strike. The toe side of upper edge 17 has a more acute slope than the heel side of upper edge 17 but generally speaking head 10 gives the appearance of an isosceles triangle. Both vertex 18 and toe 12 are curved as is sole portion 13. A notional point 20 on striking face 21 has a significance best ₅ explained with reference to Figure 2. Figure 2 illustrates an end view of head 10 from which it can be seen that the notional point 20 represents the intersection of an extension of striking face 21 with the centre-line 16A of hosel 16. Figure 2 shows a head 10 with striking face 21 having a loft of 32 degrees which is representative of a six iron but the principles of the invention can be utilised throughout the set of irons_n including pitching and sand wedges . With putters and driving irons the loft will be considerably smaller say of the order 0 to 15 degrees. A front portion 22 of sole portion 13 may be relieved at 23 by the angle θ which can range from 0 to 20 degrees throughout the set of irons and can provide, for example, the so called "bounce" angle in the sand wedge. Relieved portion 23 assists in preventing scuffing and making a clean strike. Striking face 21 is formed by a relatively thin parallel sided striking plate-like member 24 of between 1 to 6mm thickness, preferably 2-3mm. A reinforcing side web 25 on rear of toe portion 12 extends upwardly from sole portion 13 to a position on strike plate 24 short of vertex 18 as best seen in rear view of Figure 5 and partially dotted in Figure 1. Reinforcing web 25 generally follows the contour of upper edge 17 but stops well short of vertex 18, for example, web 25 has a height of approximately 40mm measured vertically. A somewhat similar web 26 is arranged to merge with hosel 16 on the heel side of head 10. It is important to note that upper edge 17 is plain and free and consists of the thickness of strike plate 24, that is, there is no upper rearwardly extending flange as in a conventional cavity back iron. An important aspect of the invention is best explained with reference to Figure 4 which is a section on X-X of Figure 3 taken generally through vertex 18. Firstly it can be seen that plate-like member 24 forming striking face 21 extends to sole portion 13 which facilitates the attainment of uniformity of reaction properties from strike face 21 during impact. People who have tried clubs fitted with this particular head have said it exhibited an improved feel and it is believed this could be due to the relative thinness and relatively large area of strike plate 24 supported between side webs or supports 25,26. Extending rearwardly from strike plate 24 at the bottom thereof is a relatively thin horizontal web 27 having somewhat similar thickness dimensions to strike plate 24. Web 27 extends towards and merges with a symmetrically disposed curvilinear relatively large, preferably, bulbous shaped rear flange 28 which from Figure 4 is seen to be much larger than thin web 27. Web 27 ^■

can have a length of up to 25mm but preferably is in the range 6 to 10mm. Toe web 25 also merges with rear flange 28. The mass of the bulbous flange 28 at the rear of the head supported mainly by thin web 27 is believed to provide a moment assisting the follow through. As seen from Figure 6 which is a sectional view on A - A of Figure 5 rear flange 28 extends in a gradual curve sloping towards respective heel and toe portions 11, 12 The convergence towards respective heel and toe portions means that the moment arm diminishes from a maximum at approximately the centre of rear flange 28 to a mimimum at the heel and toe portions 11, 12 which facilitates the follow through after the strike. The maximum face dimension occuring at vertex 18 near the middle of the head instead of near the toe as in conventional clubs means that the centre of gravity of the head is disposed towards the heel. This is somewhat contrary to conventional practice and, therefore, all the more surprising that testing of golf clubs using the head of the invention is found to provide a smooth strike. As represented by the dots in Figure 3 plain striking face 21 can be finished with a frictional surface , for example, a thermal spray coating, diamond faced coating , tungsten carbide coating , plated nickel alloy or the like. The main aim is that striking face 21 is provided with a mildly abrasive hard coated surface. Whilst there is no reason why conventional grooves could not be used it is much preferred that a frictional coating as enumerated is used. Alternatively striking face 21 may be provided with a smooth visually matt surface which has been found to provide a satisfactory feel at impact. In a practical embodiment of the present invention the distance between vertex 18 and centre line 19 is in the range 6 to 20mm. The centre line of the centre of gravity of the head is between 30 and 40mm from the heel 11. The vertical distance or height from the sole 13 to vertex 18 is approximately 53mm bearing in mind that Figure 1 is a view normal to striking face 21. The length from toe to heel could be up to 120mm but preferably is 97mm. The radii of the toe 12 and vertex 18 could be respectively 13 and 20mm. The material of the head may be stainless steel, cast steel or forged steel. Other materials could be used, for example, high impact plastics or glass, ceramic or suitably weighted composite materials. If a light material, for example, an alloy is used then suitable weighting, preferably, in the sole would be provided.

It should be noted that we believe that because of the higher impact forces in irons and woods, as compared with putters, the position of the centre of gravity is more important.

Claims

1. A head for a golf club, the head having a heel portion and a toe portion, a lower flanged sole portion extending between the heel portion and the toe portion and an upper edge portion, the upper edge portion being plain and free of any rearwardly extending flange portion, the head including a striking face and a hosel wherein the head is in the form substantially of an isosceles triangle, the vertex of the triangle being adjacent the centre-line of the striking face thereby being displaced from the toe and on the side of the head opposite the sole portion, whereby the centre of gravity of the head is displaced towards the heel.

2. A head according to claim 1, wherein the vertex is displaced from the toe by about one third of the length of the sole portion.

3. A head according to any of the preceding claims, wherein the striking face is formed by a relatively thin plate like member.

4. A head according to claim 3, wherein the upper edge portion of the strike plate is free of any flange member.

5. A head according to claim 3 or claim 4 including a relatively thin web member extending rearwardly from the strike plate and merging with a relatively large flange member.

6. A head according to claim 5, wherein the rear web member is located substantially at the bottom of the strike plate.

7. A head according to claim 5 or claim 6, wherein the relatively large flange member is bulbous shaped.

8. A head according to any of claims 5 to 7, wherein the flange member extends in a symmetrically disposed curve between the toe portion and the heel portion.

9. A head according to any of claims 3 to 8, wherein the strike plate and rear web member is between 1 to 6mm, preferably 2 to 3mm, in thickness.

10. A head according to claim 3 and claim 5 including a web member supporting the strike plate at the toe.

11. A head according to claim 10, wherein the supporting web member generally follows the contour of the upper edge portion but stopping short of the vertex so that the upper edge portion is free of any flange member.

12. A golf club head according to any of the preceding claims, wherein the striking face includes a frictional surface.

13. A head according to claim 12, wherein the frictional surface is selected from the group comprising thermal spray coating, diamond faced coating, tungsten carbide coating or plated nickel alloy coating.

14. A head for golf club according to any of the preceding claims, wherein the strike plate is provided with a plain surface having a visually matt finish.

15. A golf club having a head in accordance with any of the preceding claims, wherein the golf club is selected from the group comprising woods, irons and putters.