GB2232895A

GB2232895A - Golf ball

Info

Publication number: GB2232895A
Application number: GB8914000A
Authority: GB
Inventors: John Richard Aldridge
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-06-17
Filing date: 1989-06-17
Publication date: 1991-01-02
Anticipated expiration: 2009-06-17
Also published as: GB2232895B; GB8914000D0

Abstract

A golf ball 1 is of generally solid construction and has a cylindrical, diametrical blind bore 3. A threaded bolt 4 is received with a clearance C in the bore. A spring 5 has one end 5b secured to hexagonal nut 5 threadably engaged on bolt 4; the end 5a of the spring is secured to the circular end surface 3a of bore 3. Rotation of the bolt results in a translational movement of the nut along the bore and thus to a displacement of the centre of gravity of the golf ball. The golf ball 1, with its displaced centre of gravity, may be used to simulate putting strokes on a sloping surface whilst actually playing on a flat surface. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO GOLF This invention relates to improvements in or relating to Golf and more particularly to a Golf ball for skill practice sessions.

A major contributory factor in developing playing ability in Golf is in frequent "putting" practice sessions. Hence, purpose made putting greens are quite commonplace in order to enable putting skills to be practised and developed and these are sometimes constructed with an artificial playing surface. Additionally, keen golfers may be able to practise in the comfort of their own home or office on a carpet or generally flat playing surface, whilst using a purpose made or makeshift accessory for the hole which is aimed at during the putting stroke and which is to receive the golf ball. In order to improve putting ability the playing parameters present in the putting practice sessions (even if only in the home or office) should ideally be as close as possible to those present on the golf course.As a matter of convenience the playing surface employed for such practice sessions is usually flat and it is believed that this tends to be disadvantageous since greens on the golf course will usually have a slope and the behaviour of the golf ball on a slope will, of course, be different to its behaviour on a flat surface. Additionally, parts of the same golf course will normally have different slopes on different greens and the golfer needs to acquire a repertoire of putting shots from different distances over different slopes. Practice sessions on a generally flat playing surface would thus seem of little or no value to the acquiring and maintenance of such a repertoire.Such sessions may help in generally acquiring a "feel" for estimating the strength necessary for playing a putting stroke over a specific distance (given that the playing surface will be somewhat different to that of the golf course which is itself variable due to relative wetness and length of grass and so on) but still tend to be disadvantageous or lacking in certain respects since they would not appear to provide a high enough level of convenient "putting", or variation in putting practice, at least for the serious golfer.

An object of the present invention is to provide a golf ball for practising putting skills and the strokes required for sloping playing surfaces.

According to a first aspect of the present invention there is provided a golf ball provided with a displaced, preferably adjustable, centre of gravity.

By this aspect of the present invention the centre of gravity of the golf ball is displaced so that, on suitable orientation of the ball before striking, it may be struck by a putting iron and travel over a flat playing surface in such manner as to simulate or mimic travel over a sloping surface of a green of a golf course.

An alternative solution to the problem of providing a suitable putting practice session for a sloping playing surface may simply be to provide a sloping rather than flat playing surface, for example on the carpet or on the practice putting greens. However, such a solution would seem expensive and/or impractical in many situations (for example in the office or corridor where practice puts of up to twenty feet or so may be required). Additionally, practice is required over a range of sloping surfaces and the provision of a suitable range of bulky playing slopes, at least for use in the home or office, to enable putting over such distances would seem to be even more impractical.

It is envisaged that the golf ball will usually have a centre of gravity which may be conveniently adjusted over a range of preselectable positions to enable simulation of various putts over particular distances with particular slopes of playing surface. Preferably, these preselectable positions will be calibrated on the ball.

Further according to the present invention there is provided a method of simulating a putting stroke on a slope comprising: a) aiming to one side of a hole, b) striking a golf ball with a displaced and, preferably adjustable, centre of gravity such that the ball is pulled either to the left or right of the stroke towards the hole whilst travelling on a flat playing surface.

Still further according to the present invention there is provided a series of golf balls all having a centre of gravity which is displaced, the degree of displacement of the centre of gravity being different in each case in order to simulate different putting conditions over slopes of different angles and/or over different distances from a hole. Some or all of the balls may have a centre of gravity which is adjustable and the calibration of the adjustment may be different in each case.

Usually the same golf ball will be provided with a sufficient degree of adjustment of its centre of gravity that it may be used to simulate a putt over precorrelated different angles of slope from similar distances away from a practice target hole when aiming at a pre-correlated distance to one side of the hole. Such pre-correlated distances are, preferably, marked out to one side of the hole.

Therefore, still further according to the present invention there is provided apparatus for practising golf putting, said apparatus comprising at least one golf ball with a displaced, preferably adjustable, centre of gravity and a target hole (or golf ball receiving means), and marker means being provided, in use, to one side of the hole which is pre-correlated to one or more distances from the hole such that a player is able to aim in the direction of a defined mark of the marker means from a pre-correlated distance away from the hole when making the putting stroke.

In one embodiment of the present invention the golf ball has a centre of gravity which is adjustable, preferably along a radial line of the ball, by relative rotation of part of the ball. The ball may be provided with a bore or recess receiving a threaded bolt retained in said bore or recess such that rotation of said bolt relative to the remainder of the ball causes translational movement of a nut or weight threaded on the bolt along said radial line and/or along the bore or recess, preferably, whilst maintaining the axial location of the bolt (i.e. whilst restraining movement of the bolt in or out of the bore or recess).

The nut may also be arranged to move against the action of a spring biassing force. The ball may have a tension spring means (e.g. a close coiled spring) secured at a blind end of the bore or recess (e.g. by adhesive), with said nut being secured to one end of the spring means remote from said blind end, and on appropriate rotation of the bolt, the nut is induced to translate along the bore/recess whilst being restrained against rotation by the spring means and under the action of spring biassing provided by the spring means.

The bore or recess may extend almost all the way through the bore such that a free end of the bolt is accessible for rotation (the bolt may be provided with a slot or the like for turning by a coin or other tool) or, alternatively, the ball may be divided generally into two halves which are, preferably, snap-fitted together by resilient snap-fit engagement means, said bore or recess possibly only extending through one half of the ball and the bolt being fixed to the other half and rotatable therewith relative to said first half.

Most preferably, a scale is provided on the ball such that a preset angular orientation of the bolt (the relative rotational part) represent a defined position of the centre of gravity of the ball required in order to simulate a particular putt over a particular distance over a particular slope from a target practice hole. The scale may be a generally circular scale provided around the free end of the bolt (or around one half of the ball where one half is relatively rotatable with respect to the other) and, preferably, a relatively small degree of relative rotation will provide a suitably large adjustment of the centre of gravity.For example, a 1/4 turn adjustment may allow a putt to be made from twelve feet away from the practice hole over a suitable simulated angle of slope and a 1/2 turn adjustment may allow a putt to be made from twelve feet away over a greater simulated angle of slope.

Alternatively, the golf ball may be such that weights can be introduced into a bore in a pre-defined manner to alter the position of the centre of gravity in a correlated manner.

In yet a further embodiment, the golf ball is provided with a bore of matching configuration to a nut or weight (e.g. a square bore with a square nut) and a bolt is permanently secured in a bearing member which itself is secured at a blind end of the bore. Thus the axial position of the bolt is fixed whilst rotational movement of the bolt is allowed, and translational movement of the nut is induced along the bore on appropriate rotation of the bolt.

Any suitable means may be employed for adjusting the centre of gravity of the ball.

Other advantageous features of the present invention will be asertainable from the following description.

Embodiments of a golf ball, apparatus, and method of simulating a putting stoke on a sloping green, in accordance with the present invention will now be described, by way of example only, with reference to the accompanying simplified diagrammatic drawings in which: FIGURE 1 shows a cross section taken through the first embodiment of a golf ball; FIGURE 2 shows a similar cross section taken through the second embodiment; FIGURE 3 shows a similar cross section taken through the third embodiment; FIGURE 4 shows a similar cross section taken through the fourth embodiment, and FIGURE 5 shows the general ideal pattern of paths travelled of the golf ball to a hole from various distances.

Referring to FIGURE 1 of the drawings, a golf ball 1 (shown in cross section) is of generally solid construction (any suitable material may be used, for example hard rubber) with an outer shell 2 conforming to the usual contoured and textured surface of a standard golf ball (the detail of the outer surface of the golf ball is not shown for ease of illustration).

A generally cylindrical, diametrical, blind bore or recess 3 is provided in the ball 1 as shown and a bolt 4 with an external screw thread is received with a clearance c in the bore and is arranged co-axially therewith. The bolt 4 extends all the way into the bore 3, which bore extends almost all the way through the ball 1, and has a flat circular end surface 4a which engages the flat circular end surface 3a defined at the blind end of the bore 3. A close coiled tension spring 5, of slightly lesser external diameter than the bore 3, is permanently secured at one end 5a thereof in the bore 3, in coaxial relation therewith, for example by means of an adhesive, to the end surface 3a.

The other end 5b of the spring 5 is permanently secured (for example by adhesive or welding) to a hexagonal nut 6 which is threadably engaged on the external screw thread of the bolt 4. The hexagonal nut is such that the maximum dimension across its apices is just less than the diameter of the bore 3. The bolt 4 is passed through the spring 5 and the external thread of the bolt 4 is free from meshing engagement with the internal surface of the spring 5. At the open end 3b of the bore 3, the bolt 4 is received in a plug 7 (for example of hard rubber or the like) which seats the bolt and is secured (for example by adhesive) into the bore.

The plug 7 effectively seals the bore 3 from the ingress of moisture and the like.

In this example, the bolt 4 is of headless form and the end 4b of the bolt 4 received in the plug 7 is shaped to conform to the exterior surface of the golf ball (the free end of the plug 7 is also shaped similarly to conform to the exterior surface of the ball). End 4b is, in this instance, provided with a slot 4c suitably shaped for the insertion of a coin or the like, which coin may thus be used to rotate the bolt 4 about its axis, said rotation being relative to the nut 6 and plug 7. On assembly, initially the spring 5 is introduced into the bore 3, and end 5a is secured to the end 3a of bore 3 (e.g. by adhesive), and then the nut 6 is secured to the spring, or, alternatively the spring and nut are introduced as a unit into the bore and secured thereto.

Then the bolt 4 is introduced into the bore 3 and screwed through the nut 6 (the nut 6 is restrained from rotation about its axis by its securement to the spring 5) until the end surface 4a of the bolt engages the blind end surface 3a of the bore 3. Thus the bolt 4 is correctly axially located relative to the bore 3. Further rotation of the bolt 4 in an effort to screw the bolt further into the bore 3 results in a translational movement of the nut 6 (against the tension spring force provided by spring) along the bore in the direction of arrow A, since- the bolt is prevented from further axial movement into the bore by its engagement with end surface 3a. As the nut 6 moves in the direction of arrow A, the coiling of the spring 5 stretches out to accommodate the movement of the nut whilst still restraining rotation of the nut on its axis.Clearly, rotation of the bolt 4 in the opposite sense will cause the nut 6 to return to its original position as shown in FIGURE 1 with the spring 5 once again in its close-coiled position.

In conclusion, rotation of the bolt 4 in the screwing-in direction (i.e. clockwise) from the position as shown in FIGURE 1 will cause a translational movement of nut 6 in the direction of arrow A, whilst the relative axial location of the bolt in the bore remains unchanged (largely by the action of the tension force of the spring 5). As the nut 6 is translated, so the centre of gravity of the golf ball will move also in the direction of arrow A.

The centre of gravity may be arranged at the centre of the ball (so that it behaves as a normal golf ball) at any convenient axial location of the nut 6, for example as shown in FIGURE 1 the centre of gravity may be at the centre of the ball. The pitch of the mating threads of the bolt 4 and nut 6, and ratio of the weight of the nut to the weight of the ball are preferably such that a relatively small degree of rotation of the bolt -(for example 90 ) causes a lateral movement or pull of the ball on a flat surface of approximately 1 foot (.30 metres) on a putt 12 feet (3.66 metres) from the hole.

In any event, a circular scale is provided (possibly on the exterior surface of plug 7 or at least around the free end 4b of the bolt) to indicate the set angular orientations of the bolt required to move the centre of gravity of the ball by a specified amount. The slot 4c itself may be used as a pointer to be aligned with set marks of the scale.

FIGURE 1 illustrates an arrangement for varying the centre of gravity of a golf ball in a preselectable manner and the reasons for varying the centre of gravity and preferable scale calibrations which may be applied will be discussed later on in relation to FIGURE 5 after discussion of FIGURES 2, 3 and 4 which now follows.

FIGURE 2 shows an arrangement similar in essence to FIGURE 1 except that the bore or recess 3' is only provided in one half h1 (the left half as shown in the FIGURE) of the golf ball 1'. The two halves h1, h2 of the ball 1' are snap-fitted together by any suitably resilient snap-fit engagement means (not shown but e.g.

circular co-operating resilient ribs provided around adjoining rims r1, r2 of the halves hl, h2) which allows relative rotation of the two halves hl, h2 about the axis of bolt 4' whilst retaining the two halves h1, h2 together. Bolt 4' is permanently attached to, and rotatable with, half h2. This arrangement works similarly to that shown in FIGURE 1 since rotation of the half h2 in the clockwise direction relative to half h1 will cause a translational movement of the nut 6 in the direction of arrow A and thus a movement of the centre of gravity.Additionally, half h2 is lockable in any one of a plurality of preselected angular orientations with respect to half h1 on rotation about the axis of bolt 4 Such locking may be provided by any convenient means such as a plurality of resilient pips p attached to half h1 which freely locate in a circular groove g but which engage raised projection receiving means (not shown) in the groove g at selected angular locations to positively lock the angular orientation of half h1 with respect to half h2 , in such manner that the locking may be freed when desired on the application of a suitably manually applied positive unlocking force.

The selective locking of the halves h1, h2 in relative preset angular orientations may itself be provided on, or as part of, the resilient snap fit engagement means. Once again a suitable circular scale (not shown) may be provided on the ball 1' and this is conveniently provided around the circumference of half h1 adjacent half h2 in a manner which should easily be envisaged with a particular mark or pointer on half h2 being alignable selectively with markings on the scale.

FIGURE 3 represents a third embodiment of the golf ball 1'' which has a through bore 3'' provided as shown.

The bore 3?? has shaped plugs 7' at either end and it is envisaged that weights of various sizes may be located at fixed positions within the bore, by any convenient means (for example one or more weights could be located in the bore by suitable spacer blocks - e.g. of high density foam), in order to vary the position of the centre of gravity of the ball along the axis of the bore in a manner which should readily be determinable.

FIGURE 4 shows a fourth possible embodiment of a golf ball 100. In FIGURE 4 bolt 102 has a plain cylindrical end 102' provided with a circumferential groove 103. Bolt 102 is received into a bore 104 of square cross-section which corresponds to the square cross-section of nut 105. End 102' is received into a plastics box-like restraining and bearing member 106 which has a square section corresponding with that of bore 104 and which is permanently secured (for example by adhesive) at the blind end of the bore. The engagement of the member 106 and bolt end 102' is such that the bolt cannot be withdrawn from the member.Wall 106a may have been sufficiently resilient to admit end 102' into member 106 through circular hole 106b in wall 106a (hole 106b being of slightly less diameter than the bolt end 102') until wall 106a snap engages into groove 103, or alternatively member 106 could be moulded in situ around end 102'. An optional compression spring S is provided loosely in between member 106 and nut 105 as shown to take up any axial play of the wall 106a in the groove 102 and possibly allow an easier translational movement of the nut 105. As in the previously described arrangements the relative axial position of the bolt is fixed and appropriate rotation of the bolt causes translational movement of the nut. In this instance, the bolt 102 is shown with a head H which spans the square bore 104 and is seated in an appropriately shaped recess at the end of the bore.Once again a suitable scale may be provided on the ball.

FIGURE 5 illustrates how a golf ball of the present invention can be used to practice various putting strokes over various distances on a flat playing surface but simulating play on a sloping surface such as that more usually encountered on a golf course. The golf ball 1, 1', 1'', 100 is set up at position A shown in FIGURE 5, distance a from the hole, which distance may be, for example, twelve feet from the hole. The centre of gravity of the ball is set by rotating the bolt on its axis to a preset position against the scale (preferably a 1/4 turn) which will pull the ball one foot laterally over a putt of twelve feet. Therefore, the player when standing opposite the hole at position A, as shown, should aim at the position marker 11 (which is one foot from the hole to the right of the player) in order for the ball to travel along the track X (indicated by dashed lines) into the hole.Obviously, before making the putting stoke from left to right in FIGURE 5, the ball should be oriented with the bolt axis horizontal and generally transverse to the direction of the stroke and the centre of gravity should act through the ball at a position displaced to the left of centre, so that the ball will be biassed to the left and travel approximately in the curved track X as indicated. Thus, the putting stroke can be made under conditions which simulate play on a sloping green with the direction of the slope as shown in FIGURE 2, the curved track X simulating a falloff of the ball down the slope.

Similarly, under the aforedescribed parameters, for a putting stroke to be played from distance 2a (e.g.

twelve feet) away from the hole (position B) the player aims at marker 21 at a position two feet (.61 metres) to the right of the hole (downward direction as shown in FIGURE 5) and the optimum track the ball should travel to the hole is along track y. The golf ball may be such that this second putt simulates play on a green having the same angle of slope as simulated in the first putt from six feet 1.83 metres away and no further adjustment of the bolt need be necessary to alter the centre of gravity. Once again, play on the same slope may be simulated for a putt of distance 3a (e.g. eighteen feet) from the hole (position C) and the player aims at marker 31 (3 feet - .91 metres) to the right of the hole; the optimum track for the ball is along track Z. Again the golf ball may be such that no further adjustment of the bolt or centre of gravity is required.

It is envisaged that the ball will be calibrated such that the putt will simulate play on a slope of known angle and if it is desired to simulate play on a different slope the bolt may be rotated accordingly a pre-set degree in order to move the centre of gravity of the ball accordingly and alter the pull on the ball in a predirected manner. Thus, the player will need to aim further to the right of the hole from the same distance away for a centre of gravity displaced further from the centre of the ball and thus under simulation of a slope of greater angle. If a player wishes to practice for a slope angled in the opposite direction as shown in FIGURE 5, the ball is oriented with the centre of gravity on the right of the ball in order to pull the ball to the right and the tracks to the hole will be the appropriate mirror images of the tracks X, y, z from the distances a, 2a, 3a (6 feet, 12 feet, 18 feet).

It is to be understood that individual features as aforementioned or as shown in the drawings or combinations thereof, or functions appertaining thereto, may be patentably inventive and any specific term as used herein should not be construed as unnecessarily limiting and the scope of such term should extend to, and may be replaced by, any reasonable equivalent or generic expression.

Claims

1. A golf ball provided with a displaced, preferably adjustable, centre of gravity.

2. A golf ball as claimed in Claim 1 having a centre of gravity which is adjustable over a range of preselectable positions.

3. A golf ball as claimed in Claim 2 in which said preselectable positions are calibrated on the ball.

4. A golf ball as claimed in any one of the preceding claims having a sufficient degree of adjustment of its centre of gravity that it can be used to simulate a putt over pre-correlated different angles of slope from similar distances away from a practice target hole.

5. A golf ball as claimed in any one of the preceding claims having a centre of gravity which is adjustable by relative rotation of part of the ball.

6. A golf ball as claimed in Claim 5 in which the centre of gravity is adjustable along a radial line of the ball.

7. A golf ball as claimed in Claim 5 or Claim 6 in which the ball has a bore or recess receiving a threaded bolt retained in said bore or recess such that rotation of said bolt relative to the remainder of the ball causes translational movement of a nut or weight threaded on the bolt along said radial line and/or along the bore or recess.

8. A golf ball as claimed in Claim 7 in which the axial location of the bolt is maintained during said translational movement of the nut or weight.

9. A golf ball as claimed in Claim 7 or Claim 8 in which the nut or weight is arranged to move against the action of a spring biassing force.

10. A golf ball as claimed in Claim 9 having tension spring means secured at a blind end of the bore or recess with said nut being secured to one end of the spring means remote from said blind end, and on appropriate rotation of the bolt, the nut is induced to translate along the bore/recess whilst being restrained against rotation by the spring means and under the action of spring biassing provided by the spring means.

11. A golf ball as claimed in any one of Claims 7 to 10 in which the bore or recess extends almost all the way through the bore such that a free end of the bolt is accessible for rotation.

12. A golf ball as claimed in any one of Claims 7 to 10 in which the ball is divided generally into two halves.

13. A golf ball as claimed in Claim 12 in which said halves are snap-fitted together by resilient snap-fit engagement means.

14. A golf ball as claimed in Claim 13 in which said bore or recess only extends through one half of the ball and the bolt is fixed to the other half and rotatable therewith relative to said first half.

15. A golf ball as claimed in any one of the preceding claims in which a scale is provided on the ball such that a preset angular orientation of the bolt (the relative rotational part) represents a defined position of the centre of gravity of the ball..

16. A golf ball as claimed in Claim 15 in which the scale is a generally circular scale provided around the free end of the bolt, or around one half of the ball where one half is relatively rotatable with respect to the other.

17. A golf ball as claimed in any one of Claims 1 to 4 which is such that weights can be introduced into a bore in a predefined manner to alter the position of the centre of gravity in a correlated manner.

18. A golf ball as claimed in Claim 5 with a bore of matching configuration to a nut or weight and with a bolt permanently secured in a bearing member which itself is secured at a blind end of the bore, the arrangement being such that the axial position of the bolt is fixed whilst rotational movement of the bolt is allowed, and translational movement of the nut is induced along the bore on appropriate rotation of the bolt.

19. A golf ball substantially as herein described and illustrated with reference to FIGURE 1, or FIGURE 2, or FIGURE 3, or FIGURE 4 of the accompanying drawings.

20. A method of simulating a putting stroke on a slope comprising: a) aiming to one side of a hole, b) striking a golf ball with a displaced and, preferably adjustable, centre of gravity such that the ball is pulled either to the left or right of the stroke towards the hole whilst travelling on a flat playing surface.

21. A method as claimed in Claim 20 in which the golf ball is used to simulate a putt over pre-correlated different angles of slope from similar distances away from a practise hole.

22. A golf ball as claimed in Claim 21 in which said pre-correlated distances are marked out to one side of the hole.

23. A method as claimed in Claim 21 and substantially as herein disclosed with reference to Figure 5 of the accompanying drawings.

24. A series of golf balls all having a centre of gravity which is displaced, the degree of displacement of the centre of gravity being different in each case in order to simulate different putting conditions over slopes of different angles and/or over different distances from a hole.

25. A series of golf balls as claimed in Claim 24 in which some or all of the balls have a centre of gravity which is adjustable.

26. A series of golf balls as claimed in Claim 25 in which the calibration of the adjustment is different in each case.