BACKGROUND OF THE INVENTION The game of golf has never been as popular as it is today and some recent estimates have suggested that there may be as many as 35 to 40 million golfers worldwide. The level of participation in the sport of golf is rising every year. With the increased participation in golf there comes also an increase in the participation in golf related activities such as the use of golf driving ranges, indoor golf courses, mini golf and the like. In fact, golfers are known for their passion for their sport and will go to great lengths to ensure that their passion for the game can be satisfied, in even the most unlikely surroundings.

For example, it has become common place for cruise ships (the popularity of which are also on the rise) to offer a golf driving range facility where golf balls can be hit from the boat into the sea. Similar facilities exist at various sea or lakeside resorts. Such activities are obviously associated with a negative environmental impact given that"regulation"golf balls for use in competition golf are produced of polymeric material that is not readily degradable.

The result being that man's passion for golf, or at least some form of golf related activity, is causing a build up of used golf balls on sea and lake beds and in other areas.

It is with these environmental concerns in mind that the present invention has been conceived.

The invention, however, relates not only to the provision of balls for use in golf related activities but also for balls useful in practice or leisure relating to sporting activities such as cricket, baseball, softball, hockey, hurling, ice hockey or roller hockey where persons interested in such pursuits may wish to strike a ball that takes the general form of a regulation ball from their chosen sport, with a striking means as used in their sport and propel the ball into the sea, lake, rivers or streams, bush, desert, into a snow field, from a mountain peak or cliff or into other areas.

As the biodegradable balls of the invention may have limited elastomeric properties relative to regulation balls from the sport concerned, it may be necessary to modify the striking means used to propel them, to more closely approximate the flight profile and feel associated with striking a regulation ball with a regulation striking means (eg. club, bat, stick, etc.). The "feel"associated with striking a regulation golf ball in the central region of a regulation golf club face is very important to golfers and involves a combination of minimal vibration through the golfers hands and a sound indicative of sweet contact.

With this background in mind, it is an object of the present invention to provide biodegradable balls that can be used in practice or leisure activities relating to sports such as those mentioned above, as well as modified striking means that may be used in conjunction with them.

Other objects of the present invention will become apparent from the following detailed description thereof.

SUMMARY OF THE INVENTION According to one embodiment of the present invention there is provided a biodegradable ball adapted to be propelled by contact with a striking means; the ball comprising a mixture of a biocompatible particulate material and a water soluble biocompatible binding agent formed into an appropriate conformation. According to another embodiment of the present invention there is provided a method of producing a biodegradable ball adapted to be propelled by contact with a striking means; the method comprising mixing a biocompatible particulate material and a water soluble biocompatible binding agent and forming the resulting mixture into an appropriate conformation, under conditions appropriate to cause binding of the mixture.

According to a further embodiment of the present invention there is provided a biodegradable ball adapted to be propelled by contact with a golf club and having size, weight and shape approximating that of a regulation golf ball; the ball comprising a mixture of a biocompatible particulate material and a water soluble biocompatible binding agent.

According to a still further embodiment of the present invention there is provided a sporting or leisure kit comprising a biodegradable ball as referred to above and a striking means adapted for propelling the ball by contact; the striking means having an elastomeric material provided on a striking surface thereof.

According to a still further embodiment of the present invention there is provided a practice or leisure golf kit comprising a biodegradable ball as referred to above and a golf club adapted for propelling the ball by contact; the golf club having an elastomeric material provided on a club face thereof.

In a preferred embodiment the particulate material is selected from one or more of sand, salt and particulate plant matter. Preferably the binding agent is a plant or animal derived binding agent or the binding agent is selected from one or more of gelatin, starch, gluten, sugar and gyprock. Particularly preferably the particulate matter is sand and the binding agent is gelatin.

In a preferred embodiment of the invention the biodegradable ball is formed into a conformation approximating the size, weight and shape of a regulation golf ball, cricket ball, baseball, softball, hockey ball, hurling ball, ice hockey or roller hockey puck.

In another aspect of the invention a biocompatible pigment is included in the mixture and/or a biodegradable pigment on a surface of the ball.

According to another embodiment of the present invention there is provided a golf club head comprising a striking plate and a body having a hozzle and face; an elastomeric material being located between the face and the striking plate.

In a preferred embodiment of the invention the striking plate and elastomeric material are affixed to the face of the body by a screw or screws.

In another aspect of the invention the striking plate is affixed to the elastomeric material by heat welding or adhesive.

In a further embodiment of the invention the elastomeric material is affixed to the face of the body by adhesive.

In a still further embodiment of the invention the elastomeric material is affixed to the face of the body by an interlocking tongue and groove arrangement.

According to another embodiment of the present invention there is provided a golf club comprising a shaft affixed to the hozzle of a golf club head as defined above.

According to another embodiment of the invention there is provided a golf club to which there is releasably affixed to a face thereof a striking plate; an elastomeric material being located between the face and the striking plate.

In a preferred embodiment of the invention a releasable adhesive is located on a surface of the elastomeric material which is affixed to the golf club face.

In another embodiment of the invention there is provided a kit comprising a golf club as defined above and one or more golf balls having limited elastomeric properties.

BRIEF SUMMARY OF THE DRAWINGS The present invention will be further described with reference to Fig. 1 which shows a perspective front view from above of one example of a golf club according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Throughout this specification and the claims which follow, unless the context requires otherwise, the word"comprise", and variations such as"comprises"and"comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

As explained above it is an intention of the invention to provide biodegradable balls for practice sporting or leisure pursuits that can be propelled by contact with a striking means into the natural environment, whether that be a water or dry land environment or indeed within a man made environment such as a golf driving range. It is therefore generally the case that the balls according to the invention will be for single use only, although there may be occasions where a ball can be retrieved and re-used. In order to avoid the negative environmental aspects associated with deposit of non-degradable balls into the natural environment, the balls according to the invention must be biodegradable and produced of environmentally benign or biocompatible materials that will not result in a substantial negative impact on water or soil, animal, plant, insect or marine life etc. located in the areas to where the balls may be propelled.

By the term"biodegradable"it is intended to mean that the balls according to the invention will over time break down at least into their constituent parts of biocompatible particulate material and water soluble biocompatible binding agent. It is possible, depending upon the particulate material and binding agent adopted, that these materials themselves will break down into smaller components. It is preferred that breakdown of binding between the particulate material and the binding agent should take place over a period not exceeding one year, preferably over a period of up to a couple of months and particularly preferably over a period of days to weeks. The rate of biodegradation will of course depend upon factors such as the components incorporated within the ball and their relative amounts and the prevailing environmental conditions in the areas where balls are deposited.

The balls according to the invention are to be adapted to be propelled by contact with a striking means. In the case of balls that take the general form of regulation golf balls the ball will generally be contacted with a golf club, from a stationary position, to be propelled some distance away. In the example of cricket, baseball or softball the ball is more likely to be contacted when moving through the air or along the ground after having been thrown or bowled by another person or propelled by a machine of some description. In other practice sporting or leisure pursuits that may be based on for example hurling, roller or ice hockey or field hockey it may be the case that the ball is contacted by a striking means appropriate for that pursuit several times, perhaps by two or more players, before being contacted and propelled away and left to degrade.

The balls according to the invention comprise a mixture of biocompatible particulate material and a water soluble biocompatible binding agent that is formed into an appropriate conformation. The biocompatible particulate material will preferably be selected from one or a combination of sand, salt and particulate plant matter. It is of course possible for the particulate material to be of varying particle size or grade. For example, the particulate material chosen will depend upon the properties required in the ball that is to be produced.

The particulate material can be selected based upon particle size and weight to ensure that the ball produced is of a weight that approximates that of a regulation ball of the sport concerned when produced according to regulation size and shape. Similarly, it may be appropriate to select particulate matter with smaller particle size if fine features are to be designed into the conformation of the ball, such as for example dimples or an imitation seam or stitching.

The proportions of components utilised within the biodegradable balls of the invention can be varied depending upon the nature of the particulate material and binding agent, and the characteristics required of the ball (for example the weight, size and shape of the ball). In one example 3 parts washed river sand is mixed with 1 part gelatin and 2 parts water (excess of which is subsequently dried off). Other binding agents could be used in relatively higher or lower proportions.

The term"sand"is intended to encompass all manner of particulate debris or crushed particulate matter obtained from rocks, coral or the like, including sea sand, silica sand, river sand and coral sand, amongst others. Similarly the term"salt"is intended to encompass a broad range of mineral salts that have a generally benign impact on the environment, at least at the relatively low levels that would be incorporated into the balls of the invention. Non- limiting examples include epsom salts (hydrated magnesium sulphate), sodium chloride and potassium chloride, amongst others. The particulate plant matter envisaged by the invention includes a broad array of plant derived material that is provided in a particulate form, such as plant seeds or parts of seeds or wood, bark or leaf particles. It is also to be recognised that various types of particulate material may be combined depending on the requirements of the ball that is to be produced. In one slightly unusual embodiment of the invention viable plant seeds may be included within the biodegradable ball such that as the ball degrades the seeds are released into the environment to allow the generation of new plants.

The binding agent utilised in the invention is also to be biocompatible in the sense that it or its breakdown products are essentially environmentally benign. The binding agent should also be water soluble, which will serve to aid breakdown of binding between the particulate material and the binding agent. The binding agent may conveniently be a binding agent that is derived from a plant or animal source such as for example tree sap, sugars, starches, gluten or cellulose related materials derived from plants or animal derived materials such as gelatin that will cause binding of the particulate material when used under the appropriate conditions.

Another example of a suitable binding agent is gyprock or plaster. The appropriate conditions necessary for causing binding of the mixture that comprises the binding agent and the particulate material will depend upon the nature of the binding agent selected. For example, in the case of gelatin, starch, gluten and gyprock it may be appropriate for the particulate material and binding agent to be combined with water before forming into the appropriate shape of the ball to be produced and then either allowing the water to evaporate naturally or to provide some accelerated drying mechanism such as oven heating or warm air application. In contrast, in the case of the use of sugars (that may of course include a broad range of sugars such as for example sucrose, fructose, glucose, amylose, sugar mixtures, etc.) it may be necessary for heat to be applied to a mixture of the binding agent and particulate material in order to allow formation of the mixture into the appropriate conformation, and such that cooling of the formed ball will allow hardening or curing into the chosen conformation.

Preferably the balls formed according to the invention will be formed into a conformation, that is shape, size and weight that approximates that of a regulation ball of the sport concerned, eg. a regulation golf ball, cricket ball, baseball, softball, hockey ball, hurling ball, ice hockey or roller hockey puck. By"regulation"it will be understood that each of such sports has national or international governing bodies that regulate upon the competition approved ball dimensions and weight, and details of such regulations can easily be obtained.

Although the balls do not need to be especially durable, due to the fact that they will generally be used only once, they should be rigid and hard enough to withstand being contacted at least once, without shattering or splitting into many pieces.

According to another aspect of the invention it is possible to incorporate pigment material either into the mixture of the particulate material and binder agent or onto the surface of the ball produced in order that the produced balls are coloured. As with the other components of the balls the pigments used should also be biocompatible so that following degradation of the balls the pigment material will not adversely affect the local environment.

The mixture of particulate material and binding agent can be formed into the appropriate conformation by, for example, moulding and optional compression. The forming method adopted will naturally depend upon the nature of the binding agent and the conditions required for effecting binding of the mixture.

It is desired, although not essential, that the finished ball will perform in a similar manner to a regulation ball of the sport concerned, after it has been contacted with a striking means and propelled. By this it is meant that it should be possible for the ball to be propelled a similar distance or at least a distance of a similar order and for the ball to adopt a similar profile through the air or along the ground (depending on the type of ball) after it has been contacted, to that of a regulation ball. For example the balls will preferably travel at least a third, preferably at least a half, particularly preferably at least two thirds and most preferably at least three quarters the distance of a regulation ball. In some circumstances, depending upon the nature of components incorporated within the ball, it may be necessary for the striking means used in the particular sport or leisure activity to be altered. For example, in the case of golf, regulation balls include elastomeric substances that allow the ball to deform once it is contacted with a golf club. This characteristic contributes significantly to the distance achieved upon striking the ball and the"feel"experienced by the golfer upon contact. Given that the materials incorporated within the balls according to the invention are not likely to be particularly elastomeric, it may be necessary in some situations to provide an elastomeric material on a striking surface of the striking means; for example providing an elastomeric material on the club face in the case of a golf club. Elastomeric materials may include rubbers, elastomeric polymers or even leather, amongst others. Golf clubs provided with elastomeric panels or layers on the club face are known and are described in US patent No. 5,697,588, US patent No. 5,333,861 and US patent No. 5,688,190. Arrangements such as these are envisaged by the present invention, and as will be understood such arrangements can easily be modified for use with the striking means adopted in other sports, such as for example with cricket bats, softball or baseball bats, hockey sticks, hurling sticks, etc.

It is also possible to better approximate the sound emitted when a regulation ball is contacted by providing a thin layer of a hard material (such as for example metal, wood, a hard polymer or a carbon or boron composite material, as well known in sporting goods manufacture) so that the elastomeric material will be located between it and the striking surface.

The invention also relates to modified striking means intended for use in conjunction with balls of the invention. In particular the invention relates to modified golf clubs. The golf clubs according to the present invention are not intended for use in competition golf play and are not considered to meet the requirements of"regulation"golf clubs as defined within the rules of golf. The clubs according to the invention are particularly intended to be used in conjunction with golf balls having minimal elastomeric properties, such as for the biodegradable golf balls of the type described above.

The simplest form of the golf club head according to the invention has a body with a face and a hozzle as is usual for any regulation golf club head. As will be understood the hozzle is the section of the club head adapted to receive a distal end of a shaft which at its proximal end will usually be equipped with a grip that is used by the golfer to hold the club. In a simple form of the invention the body of the club head may simply constitute a regulation golf club head with the striking surface of the regulation golf club head constituting the face. In other forms of the invention where the golf club head is purpose produced or modified for use as a golf club head according to the present invention the face is a side of the club head to which an elastomeric material can be affixed, to which in turn is affixed a striking plate. Although the face may in some forms of the invention be planar and angled, relative to the angle of the shaft when inserted in the hozzle, between about 5° and about 85°, it may also take other configurations. For example the face may include ridges, grooves, troughs and peaks, indented section/s or the like which may serve to aid the attachment of the elastomeric material thereto. The face may also be equipped with holes or the like for receiving fastening means that serve to aid attachment of the elastomeric material and/or the striking plate.

Naturally, the body of the club head can be produced from any material routinely used in golf club head manufacture including timber, metal, metal alloys and the like. The body may in fact include a cavity or cavities that could be filled with air or other gases or materials such as for example, cork, foam, elastomeric material, plastics material or the like. A cavity such as this may open to the face and in such an arrangement location within the cavity of elastomeric material is preferred. In one embodiment of the invention a hemispherical cavity of this type having elastomeric material located within may be adopted.

The elastomeric material according to the invention includes substances such as, but not limited to, natural rubber, polybutadiene, butyl rubber (BR), styrene-butadiene (SBR), nitrile rubber (NBR), ABS rubber, polychloroprine, silicone polymers and polyurethane. It is to be understood, however, that these specific polymer materials have been mentioned by way of example only. The elastomeric material may even constitute a spring in one form of the invention, particularly a metal spring.

The striking plate incorporated within the golf club head according to the invention may conveniently take the form of a planar plate of generally hard and impact resistant material that may for example vary in thickness between a few millimetres up to about 2cm, depending upon the resilience of the material concerned. Generally, striking plates formed of hard materials such as for example metals may be quite thin whereas those formed from plastics materials having some limited resilience may be of greater thickness. Preferred striking plates incorporated within the invention may take the approximate size of a regulation golf club face although they may of course be somewhat smaller or larger depending upon the size of the golf club head to which it will be affixed. It is possible for the surface of the striking plate that will make contact with the ball when the golf club head is in use to be contoured in a manner which may increase the coefficient of friction between the club head and ball during contact. Contouring of this nature will aid the player to impart spin upon the ball and to prevent the ball simply sliding from the striking plate during contact. For example, the surface of the striking plate can be provided with score lines, grooves or ridges or small projections or pimples that will serve to increase its surface area.

There are numerous means by which the elastomeric material and striking plate can be attached to the body of the golf club head. For example, the elastomeric material may be affixed to the face of the body by the use of adhesive or by heat welding. It is possible for the adhesive to be either a permanent adhesive or to be a releasable adhesive material.

Adhesive materials of this type are well known and readily commercially available. In the case of a releasable adhesive the elastomeric material and striking plate attached to it can be affixed to an existing or regulation golf club so that it can be temporarily modified for use in conjunction with balls having limited elastomeric properties.

In another embodiment of the invention the elastomeric material and face of the golf club head may be fixed by the use of an interlocking tongue and groove arrangement. Such an arrangement can involve a groove within the face having sides that narrow towards the face and a tongue within the elastomeric material having corresponding dimensions to the groove and which widens towards its extreme. By adopting such an arrangement the elastomeric material can be affixed to the face of the body by sliding the tongue of the elastomeric material within the groove of the body. Other fixing means such as the use of screws, clips or adhesive can simultaneously be adopted.

In another aspect of the invention the striking plate and elastomeric material can simultaneously be attached to the body by virtue of screws or clips. For example screws penetrating through holes within the striking plate and elastomeric material may threadably engage within holes through the face of the body. Similarly, it is possible for clips of various descriptions to engage with the striking plate to hold both it and the elastomeric material in position about the face of the body. Such clips may be adapted for permanent or releasable attachment of the striking plate and elastomeric material to the body of the club head.

While a number of the arrangements outlined above serve to allow simultaneous attachment of the striking plate and elastomeric material to the body of the club head it is also possible for the striking plate to be separately attached to the elastomeric material, for example by the use of an adhesive or heat welding. The elastomeric material and striking plate may also be configured to allow permanent or temporary attachment together via some form of interlocking means.

The striking plate may be produced from a variety of substances including, but not limited to, metals, metal alloys and plastics materials such as thermoplastics including polyethylene, polypropylene, poly (vinylchloride) (PVC), poly (methylmethacrylate) (PMMA) and poly carbonates or thermosetting polymers such as phenolic resins, amino resins, and epoxy resins.

Particularly preferred materials that can be utilised in forming the striking plate include metals and metal alloys, high density polyethylene, polypropylene, polycarbonates and poly vinylchloride. These materials are mentioned by way of example only and are not intended to be limiting upon the scope of the invention. A variety of materials that have the appropriate qualities of hardness and impact resistance, that would be apparent to a person skilled in the art, may be adopted.

The present invention naturally also relates to golf clubs that include the golf club heads as outlined above. Such golf clubs will generally have a shaft attached at a distal end thereof to the hozzle of the golf club head body, preferably with a grip located at the proximal end of the shaft. Preferably the layer of elastomeric material located between the face and the striking plate is between about 2mm and about 25mm, preferably between about 5mm and about 15mm in thickness. The elastomeric material may for example cover the face or just a portion of the face, for example the central section or the periphery of the face.

An example of the golf club head 1 according to the invention including a body 2 attached via its hozzle 3 to a shaft 4 is shown in Fig. 1. Only the distal portion of the shaft is shown in the figure. The club head shown in the figure takes the form of a driver. However, it is to be understood that the present invention can equally be adapted for use in relation to other types of clubs such as drivers with different loft or"irons". In the drawing the elastomeric material 5 is affixed to the face 6 of the body 2 by virtue of a tongue and groove interlocking arrangement 7. This interlocking arrangement 7 has a groove within the face 6 that has edges narrowing towards the face, with a tongue of corresponding shape located within the elastomeric material 5. Affixed to the elastomeric material 5 is the striking plate 8 having grooves 9 provided therein which serve to increase the surface are of the striking plate in the region that is intended to make contact with a ball.

In another form, the invention relates to kits that may be practice sporting or leisure kits comprising the balls of the invention in combination with the striking means that has an elastomeric material provided on its striking surface. The kits of the invention may also include a biodegradable golf ball as described above and a modified golf club as also described above. The components of such kits are intended of course to be used in combination and will be complementary to one another in the sense that elastomeric material provided on the striking means is necessary for producing the desired contact and propulsion of the particular ball concerned.

It is to be understood that the present invention has been described by way of example only and that modifications and/or alterations to the invention that has been described, that would be obvious to persons skilled in the art based upon this description, are also intended to be included within the scope and spirit of the invention as described herein and defined in the appended claims.

The invention will now be further described with reference to the following non-limiting examples: EXAMPLES Example 1 Biodegradable Golf Ball Production Using a commercially available silicon moulding compound a mould was taken of a "regulation"golf ball.

Three parts of medium grade washed river sand were mixed with 1 part of domestic powdered cooking gelatin (McKenzieSTM) and 2 parts of boiling water. The mixture was placed into the mould and allowed to cool to room temperature, after which time it was removed from the mould and allowed to dry and cure at room temperature for 48 hours.

Example 2 Performance Testing of Biodegradable Golf Balls A regular, non-professional golfer played numerous shots from the same position using a 3 wood club, with both biodegradable and regulation golf balls. The same repeatable swing was adopted in each instance. When striking the biodegradable balls a 3mm rubber pad was affixed with adhesive to the club face. There was no significant difference detected in the flight in the air and distance travelled between the two groups of balls.

Example 3 Biodegradable golf ball composition Balls sized and shaped as regulation golf balls were produced by the method outlined in example 1 and according to the following formulation which weighed 45g after 5 days air drying: 3/6 calcium based sand 2/6 silica based sand 1/6 gelatin binding agent This mix results in a sufficient degree of hardness, and a good degree of shatter resistance.

Example 4 Golf club heads Club A A wooden driver was produced with a 12mm thick special rubber pad, a 3mm thick polycarbonate face plate with 1.5mm wide x 0.25mm deep grooves at 2.5mm intervals horizontally. The club has 15 degree loft.

Club B A wooden driver was produced with an 18mm concave inserted rubber pad with a 2mm thick "balata"type golf ball material laminated on the striking face. The club has 15 degree loft.

Example 5 Ball striking test results Tests were conducted with two professional par golfers hitting the balls as described in example 3 and using both club A and club B.

Club A propelled the balls an average of 200yds (2/3 that of the distance using a normal club and ball hit by the same golf professional).

The strike sound was crisp, and the feel was"solid"and satisfying, with a good"grip"and control.

Club B propelled the balls an average of 200yds (2/3 that of the distance using a normal club and ball hit by the same golf professional).

The strike sound was dull, and the feel was"rubbery"and unsatisfying.

Club B was then fitted with a 3mm polycarbonate face plate, with grooves. 25mm x. 25mm at 3mm intervals. The sound was better, but the feel was less"solid"than with Club A, with slightly less grip and control.