WO2008110842A1

WO2008110842A1 - Improvements relating to sports clubs, bats and rackets

Info

Publication number: WO2008110842A1
Application number: PCT/GB2008/050170
Authority: WO
Inventors: Martin John Lenzini
Original assignee: Martin John Lenzini
Priority date: 2007-03-12
Filing date: 2008-03-12
Publication date: 2008-09-18
Also published as: GB0704804D0

Abstract

The positioning of multiple holes, which are left open to atmosphere and are opposite to a source of vibration to create a nodal point in the area directly below said holes. This in the instance of a golf club face allows the vibration sound waves to dissipate rearward and by positioning steps on front face directly opposite these holes a constant impact dynamic can be obtained. The reduction in vibration allows for a much improved performance and extra comfort to the player with irons and woods.

Description

Improvements relating to Sports Clubs, Bats and Rackets

This invention relates to clubs, bats and rackets used in playing ball games such as golf, cricket, tennis, table tennis, hockey, baseball etc.

Designers of such equipment are constantly faced with the problem of transferring the greatest possible amount of energy to the ball. Conventionally such clubs, bats and rackets have a sweet spot located at a central position and of fairly small in size compared with the overall surface used for striking the ball. Only if the ball is struck by this sweet spot is the maximum amount of energy transferred. Therefore, increasing the size of the sweet spot is one factor of importance. Particularly when an impact occurs away from the sweet spot, energy is wasted by causing vibrations in the club etc.

This invention arose from an observation made by the inventor in the course of machining operations in an engineering workshop using a work piece holder formed from a plate formed with numerous holes, each extending from a top surface of the plate to a position close to the bottom surface. These holes are used to extract air for the purpose of holding a work piece in position by vacuum. The inventor noticed that lubrication fluid spilt onto the bottom surface of the plate was caused, by vibrations during the machining operation creating a vacuum, to collect in circles exactly corresponding to the position and size of the holes. This indicated that the vibration was being greatly suppressed close to the closed ends of the holes. The inventor conjectured that this effect could be usefully applied to suppress vibration in sports equipment and thereby to improve performance. Experiments involving drilling holes in the rear face of a golf club to form a honeycomb pattern were found to be particularly effective in improving performance particularly for off-sweet-spot hits.

The invention therefore provides, according to a first aspect, a golf club head comprising a group of apertures. According to a second aspect there is provided a club, head, bat, or racket for use in playing a ball game comprising a body defining a front face for use in striking the ball, characterised by an array of holes, each extending into the body and terminating at a closed end adjacent to the said front face. According to a third aspect of the invention there is provided a component that in use is subjected to unwanted vibration comprising a body defining front and rear surfaces and an array of holes extending from the rear surface to positions adjacent the front surface thereby reducing vibration of the component.

Particular examples of how the invention may be employed will now be described with reference to the accompanying drawings in which: -

Figure 1 is a perspective view of a golf putter head, showing its rear face;

Figure 2 is similar to Fig 1 but showing the front face;

Figure 3 is a vertical cross-section through a driver constructed in accordance with the invention;

Figure 4 illustrates the rear face of an iron type golf club head constructed in accordance with the invention; and

Figure 5 shows some test data, derived using a launch monitoring machine, to define benefits

Referring to Figs 1 and 2 there is shown a putter head formed from a block 1 of metal formed with a ferrule IA designed to receive a handle (not shown). An array of small bores IB extend from a rear face 1C to a position close to a front face ID. The depth of the holes IB can be varied to adjust the amount of vibration feedback and various combinations of depths on the same head could be employed to fine tune the head with deeper holes each end to allow more dissipation of vibration where more vibration is generated on off centre hits . The holes IB are nested so as to form a honeycomb-like configuration. They are arranged in rows, with the rows of each row being staggered so that they nest together i.e. the holes of one row lie partly between the holes of the adjacent row or rows. The spacing between each hole and the adjacent holes is less than the diameters of the holes so that, in the region of the holes, there is more volume of space than there is metal.

Two relatively large holes 1 E at opposite ends of the head are filled with a relatively dense material (as compared with the main body of the head 1) such as lead to provide the required mass.

Referring in particular to Fig 2, the front face ID is machined to form raised circular lands I F, each being co-axial with respect to a corresponding hole IB. These lands have the effect that, when the club strikes a ball, the major forces of the impact are experienced in the regions of the lands IF where vibration is most strongly suppressed by the effects of the aligned holes IA. Though not shown on the drawing, additional lands matching those shown at IF may be added to the face ID so that the whole face is uniformly covered, including the parts opposite the large holes IE.

Fig 3 shows a driver type golf club head having a body 2 formed with a ferrule 2A for its shaft and formed with three six rows of holes 2B (alternate rows only being visible in the cross-section. These holes are analogous to the holes IB of Figs 1 and 2. There are no lands IE as these would adversely interfere with the performance of a driver.

Fig 4 shows the rear face of an iron type golf club head 3 having a ferrule 3 A for its shaft and an array of holes 3B exactly analogous to the holes IA and IB of the other embodiments. The holes 3 A open onto a conventional recess 3 C on the rear surface of the head, recess 3. The holes 3B are created by drilling and form a closely nested honeycomb structure in the material which is left after the drilling. This process creates an extremely strong, thin and lightweight face and allows perimeter weighting of club head to be maximised to help with off centre shots.

Fig 5 shows the results of tests conducted on a number 6 iron constructed essentially as shown on Fig 4 using a top professional to perform similar strokes of a golf club and to measure the resulting flight of the ball. The columns of the table are as follows. Carry is distance of ball flight

Offline -3 is 3 yards to left 3 is 3 to right 0 is straight down middle.

Total is total ball distance (flight + roll)

Ball Speed is initial ball speed off the face

Launch Angle is initial angle of ball off the club face

Back Spin is the rotation speed off the club face. The rotation with the dimples in the golf ball creates lift get ball airborne and help stop ball quicker on green. With our club the lower spin does not stop the ball stopping as quick as other clubs which must mean similar spin down range and but slower acceleration of rotation off club face.

Side Spin Sideways rotation of ball. Too much spin causes ball to go left or right

Side Angle is angle of ball travel in first few feet of ball travel. This is usually also representative of angle of club face at impact

Club Speed is club head speed directly before impact with ball.

Shot Score is the launch monitor manufactures calculation of how good a shot was. Higher the score the better. Used more to monitor player's improvement over a period

The first 6 rows item "Own" is the testers Wilson 6 iron he uses regularly. The first row shows averages and shows that an average carry figure of 164 yds.

The next 3 are for Mizumo mp57 6 iron which is probably best iron on market, the first row of these three showing averages and including an average carry value of 166 yds.

The next 4 are for the club illustrated in Fig 4 with holes 5 mm deep in rear face of 11 mm thickness. Again the first row of this group of four rows shows average figures. It can be seen that the average carry value is a very significant improvement on the other results at 174 yds and that the shot dispersion in distance was only 3.8 yds which was much more accurate than first 2 clubs. The last 4 are for a model similar to that of Fig 4 but modified to have holes 7.5 mm deep in rear face of 11 mm thickness. Here it can be seen that the average jumped to a remarkable 184 yds with similar club head speed but the shot dispersion moved back in line with the percentages achieved by the first two standard clubs.

The ratio of club head speed to ball speed off the face of 28 different make 6 irons on test 1.29 to 1.38 which is backed up by testers own iron at 1.36 and 1.37. The figures for the Fig 4 model went up to 1.4 and jumped to 1.43 for model modified version with 7.5 mm holes, suggesting that more energy is transferred to the ball as the distance between the base of the hole and the front face of the club head is reduced from 6 mms to 3.5 mms. It is presumed that further reductions would result in further improvement subject to enough metal being present to provide strength to withstand the impact.

A good driver which has a very thin titanium face only achieves a ratio of 1.46.

Claims

I . A golf club head comprising a group of apertures.

2. A golf club head according to Claim 1 comprising a body of material defining a front, ball-striking face, the apertures extending, within the body towards the front face but terminating at a position spaced from the front face.

3. A golf club head according to Claim 2 characterised in that the apertures extend from a rear face of the body of material towards the front face.

4. A golf club head according to Claim 2 or 3 characterised in that the apertures define channels having parallel axes.

5. A golf club head according to Claim 2, 3 or 4 characterised in that the parallel axes are substantially perpendicular to the front face.

6. A golf club head according to any one of claims 2 to 5 characterised in that the apertures are spaced by distances smaller than a dimension of the apertures in a plane parallel to the front face.

7. A golf club according to any preceding claim characterised in that the apertures have a linear axis.

8. A golf club head according to Claim 7 characterised in that the apertures are arranged in staggered rows so that the apertures of one row lie partly between the apertures of an adjacent row.

9. A golf club head according to any preceding Claim characterised by at least five apertures.

10. A golf club head according to Claim 9 characterised by at least ten apertures.

I I. A golf club head according to Claim 10 characterised by at least twenty apertures

12. A golf club head according to Claim 2 or any other preceding Claim when dependent thereon characterised in that each aperture has a cross -section area in a plane parallel to the front face of up to 1.5 sq cm.

13. A golf club head according to Claim 2 or any other preceding Claim when dependent thereon characterised in that each aperture has a cross-section area in a plane parallel to the front face of 1.0 sq cm or less.

14. A golf club head according to Claim 2 or any other preceding Claim when dependent thereon characterised in that the apertures define a pattern having a characteristic that varies adjacent to different parts of the front face so as to give the head a desired performance.

15. A golf club head according to Claim 2 or any other preceding Claim when dependent thereon characterised in that the apertures have depths that differ adjacent to different parts of the front face so as to give the head a desired performance.

16. A golf club head according to Claim 2 or any other preceding Claim when dependent thereon characterised by contour features on the front face associated with respective apertures.

17. A golf club according to any preceding claim characterised in that the club is classed as an iron.

18. A golf club according to any preceding claim characterised in that the club is classed as a wood or driver.

19. A golf club according to any preceding claim characterised in that the club is classed as a putter.

20. A golf club according to any preceding claim characterised in that the club is classed as a rescue club.

21. A golf club according to any preceding claim characterised by additional holes containing material of higher density than a main body of the head to increase its mass.

22. A club, head, bat, or racket for use in playing a ball game comprising a body defining a front face for use in striking the ball, characterised by an array of holes, each extending into the body and terminating at a closed end adjacent to the said front face.

23. A golf club head according to Claim 22 characterised in that the holes extend from a cavity or recess in a rear side of the head towards the front face.

24. A component that in use is subjected to unwanted vibration comprising a body defining front and rear surfaces and an array of holes extending from the rear surface to positions adjacent the front surface thereby reducing vibration of the component.

25. A component according to any one of Claims 2 to 22 characterised in that the distance between closed ends of the holes and the front face is about 6 mms or less.

26. A component according to Claim 23 characterised in that the distance between closed ends of the holes and the front face is about 3.5 mms or less.