Normal or conventional golf club heads are not generally perceived to make any noticeable sound when the head of the golf club makes contact with the ball when the player is playing golf and has the intention to hit the ball during his swing. Because of the variation in materials used in the manufacture of golf club heads it is possible to notice slight variations in the usual noise caused by some golf heads when the striking face makes contact with the ball. However, it is generally the case that golfers do not notice, or pay any attention to the sound of a golf ball making contact with the face of the golf club head.

In the game of golf, any sound being made by a golf ball coming in contact with the striking face of the club head is unimportant and has no bearing, nor does it play any part in the golf swing, or the result of the shot being played.

It is also unimportant to the player, or his golf score, whether the execution of the swing causes any kind of special noise, or sound, during the moment his club head is in contact with the face of his golf club. This is generally because the average golfer does not expect to be able to create any special, or unusual sound, when his club head strikes the golf ball.

It is generally accepted that the majority of golf clubs sound the same when hitting a golf ball and any variation in the normal sound usually relates to the fact that the golf ball has made solid contact with the face of the golf head at the optimum point on the face generally referred to as the sweetspot.

In the game of golf, for example, it is the desired intention of the player to swing the golf club in such a manner that as the club head decends in an arc towards the ball the face of the golf head makes contact with the ball on the sweetspot at the exact moment that the face of the club head is square to the target line. When this happens it is quite often referred to as a good strike by experienced players. Under normal circumstances, it is considered a perfect strike by good golf players when the club head emits a solid crack, or click, as the ball is struck and generally speaking this is the only sound which good players like to hear when hitting a golf ball.

It is an object of this invention to provide the golfer with a special kind of sound when his club makes contact with the ball and that this special sound is distinct from any previous sounds made by golf clubs when hitting the golf ball.

It is also an object of this invention that the sound which is made is quite audible from a distance and that the actual sound can be regarded as pleasing to the ear. Furthermore, it is the aim of the invention to provide any golf club head with a distinct sound of its own, which may be compared with other similar sounds being emitted by other club heads having the sound properties which are provided by this invention.

I provide a golf club head with sound properties unlike any other golf club head, such that the club head emits a variation of musical sounds, or notes, depending on where the golf ball makes contact with the striking face. Furthermore, it is an object of this invention to provide the golfer with a golf club, the club head of which is constructed in such a way as to cause a musical note to be emitted when striking the ball and to enable the player to judge the correctness of the strike at the ball by the tone emitted from the head of the club during the stroke, or swing through the ball.

It is generally understood by most golfers that a range of new materials are now being used in the manufacture of both wood clubs and iron clubs. Furthermore, it is generally understood and accepted that the best material for producing a wood club head is metal. Metal has been regarded as the most suitable material for'wood'head clubs mainly because of the hardness of the metal and also because of its hard wearing properties, but also metal wood heads are considerably more easy to manufacture than wooden headed clubs.

It is an object of this invention to utilise all the beneficial properties of metal headed golf clubs, including woods and irons and to add an extra unique and important property, namely a distinctive, musical sound, which can be heard from a significant distance.

It is an object of this invention to provide all golf club heads used on irons, woods and putters with a pleasing and distinctive musical tone when striking the golf ball.

Until now, practically all golf clubs have no"sound"when a golf ball is struck, other than the normal crack, or clunking sound which is heard when a metal golf head comes in contact with a very hard golf ball made of a solid rubber core and covered by a thin layer of thermoplastic material commonly known as Surlyn, a material manufactured by the Dupont Company.

I provide a golf club head which when assembled with a shaft and grip and used to strike, or hit a golf ball, emits a distinctive sound, which can be easily identified as being very unusual and of a more musical tone than is otherwise heard when using conventional golf clubs.

Sounds can be created by various means, specially in the case of metal wood heads.

For instance, a normally"foam filled"head can be left hollow, and when a golf ball is struck a rather"tinny", or clanking sound is emitted. This is not the kind of sound that I preferably choose to provide with this invention.

I provide a golf"wood"head, or"iron"head, with a device known commonly as a "tuning-fork", which is located in the head in such a way as to set the twin forks vibrating at the moment of impact as the face of the club head strikes the ball.

In accordance with one aspect of the invention, a golf club is provided which when struck by an object will emit a sound or tone lasting a duration greater than half a second (and preferably upto two seconds).

In accordance with another aspect of the invention, a golf club is provided which when struck by an object will/a tone or sound having the key or tone G3 or above (suitably the key G4 or above, and preferably the key G5 or above).

In accordance with a further aspect of the invention, a golf club is provided which when struck by an object emits a tone or sound having an intensity, loudness or sound level greater than 40 phons (preferably greater than 50 phons, more preferably greater than 60 phons, even more preferably greater than 70 phons, and most preferably greater than 80 phons).

In accordance with a yet further aspect of the invention, a golf club is provided which when struck by an object emits a tone or sound which is musical and/or pleasing to the ear of a listener.

In accordance with a final aspect of the invention, a golf club is provided which when struck by an object emits a tone or sound which when measured and plotted as a function of time, a curve is obtained which is for the majority of the time smooth.

Preferably the plotted curve is substantially smooth (ie not a very irregular shape with jagged peaks and valleys), and the tone or sound has a substantially regular frequency and phase.

Suitably, the invention is achieved by a golf club either in the form of an iron which is mounted with a tuning fork in the back of the head or in form of a wood preferably made of Titanium with a tuning fork mounted inside the head thereof, the arrangements being such that when the golf club hits a golf ball, a pleasant sound is emitted by the head of the club corresponding to the key G5 (or preferably the tone A above middle C) at an intensity/loudness of between 40 and 80 phons for at least half a second in duration, and preferably upto two seconds.

The invention will now be described by way of example with reference to the following drawings in which:- Figure 1 is a cross-sectional view of a wood-type golf club in accordance with the invention; Figure 2 is a cross-sectional view of an alternative embodiment of wood in accordance with the invention; Figure 3 is the front view of the woods of both Figure 1 and 2; Figure 4 shows the rear of an iron-type golf club embodiment in accordance with the invention; and Figure 5 is the iron of Figure 4 shown from one end.

In Figures 1 to 3, a wood-type club is shown, which when struck by an object, will emit a sound or tone lasting a duration greater than half a second (and preferably up to 2 seconds). Furthermore, the golf club, when struck by an object will emit a tone or sound having the key or tone G3 or above, (suitably the key G4 or above, and preferably the key G5 or above). Furthermore, the golf club, when struck by an object, emits a tone or sound having an intensity, loudness or sound level greater than 40 phons (preferably greater than 50 phons, more preferably greater than 60 phons, even more preferably greater than 70 phons, and most preferably greater than 80 phons).

The golf clubs of Figures 1 to 3, when struck by an object, will emit a tone or sound which is musical and/or pleasing to the ear of a listener. In particular, the club, when struck by an object emits a tone or sound which when measured and plotted as a function of time, a curve is obtained which is for the majority of the time smooth. Preferably, the plotted curve is substantially smooth (ie. not a very regular shape with jagged peaks and valleys), and the tone and sound has a substantially regular frequency and phrase.

In particular, the woods of Figures 1 to 3 are mounted with tone or sound-emitting means mounted within the head of the wood, preferably in the form of a tuning fork made of stainless steel or titanium. In particular, the tone or sound emitting means is a singular uniformly circular rod made of stainless steel mounted substantially vertically on the metal sole of the head by welding. In particular the rod is made of SKD 61 carbon steel, and is mounted parallel to the front face of the head.

In Figure 1, the tuning rod is mounted close to the front face of the wood, To test the musical"tone"emitted by different metal woods, we enclose herewith details of experiments that have been conducted, the results of which are in Table 1. From Table 1, it will be noted that a series of No. 1 metal woods with rods of different widths have been struck by an object. The results are that different key tones are emitted for rods which are of different widths. For the first two examples in the table, the rod is 3.5mm in width, whilst for the next two examples the rod is 4mm in width, whilst for the next two examples the rod is 5mm in width and for the final two metal woods the rod is 6mm in width. In this test, the metal woods are identical in every other respect save the width of the rod. The tests are made in respect of two similar woods with the same width of rod in order to see if the same tone is consistently given.

Further experiments were conducted, and the results of such are shown in Table 2.

In particular, Table 2 shows the results of tests conducted on identical No. 1 metal woods, where the rods are of varying lengths (20mm-28mm) and the mounting position is also varied. Furthermore, the width of the rods are also varied between 3.5mm, 4mm, 5mm and 6mm In the"reference number"given in Table 2, the number given (ie. 3,4,5 or 6) corresponds to the width of the rod tested (ie 3.5mm, 4mm, 5mm and 6mm respectively), whilst the provision of a dot before the number indicates that the rod was in a front position, whilst the dot behind the number indicates that the rod was located in the back position. The provision of a single dot indicates that a rod of 28mm in length was used whilst the provision of a double dot indicates that a rod of 20mm in length was used.

Examples in this respect are as follows:- . 3 this equates to a rod having a width of 3.5mm located in the front position, and a length of 28mm 5. this equates to a rod having a width of 5mm which is located in the back position, and a length of 28mm : 4 this equates to a rod having a width of 4mm which is located in the front position, and a length of 20mm For those heads marked with:, rods were treated to 1050° rather than the normal 650°. Heat tempering of rods for increased hardness has been found to contribute to the overall sound quality (in other words, harder is better).

In particular, when rods are heat treated, in order to make them harder, they are treated preferably between 800 and 2000°C and preferably in the range of 1000 to 1200°C.

It will be noted from the results that the position of the rods in the front or back position is not terribly relevant. Preferably, the thickness of the rods is between lmm and lOmm, and more preferably 3.5 to 6mm, whilst the length of the rods is preferably between 20 and 50mm, and most preferably between 20 and 40 mm Preferably the rods have a hardness value between 431 and harder than 17-4 (most preferably 17-4). In this regard, the harder the material that is used, the more"solid"that the note that is emitted.

Although the examples given relate to wood-type clubs made of metal, it has been found that woods made of any material can be designed in order to emit a pleasing tone or sound. In consequence the invention relates to any material for a wood head, in other words, composite, wood or metal materials.

It has been found that the distance from the top of the rod, to the top of the head, is not important.

Preferably the woods are made of a stainless steel material having a hardness of 17-4 PH.

Alternatively, the heads can be made of a titanium/aluminium composite comprising 90% titanium and 6% aluminium.

Suitably, other materials that can be used for the heads of clubs according to the invention are 431 stainless steel with a Rockwell hardness of C20,17-4 stainless steel with a Rockwell hardness of C35,15-5 stainless steel with a Rockwell hardness of C40, and 6-4 titanium with a Rockwell hardness of C35. Furthermore, the golf wood-head can be made of 6A4V- titanium having a Rockwell hardness of 32 (C and D). Suitable other materials that could be used for the head are maraging steel, A-G aluminium, standard aluminium, titanium and cerent. In particular, 7075-T6 aluminium and 6AL4V titanium can be used.

In all the woods tested for which results are shown in Tables 1 and 2, a stainless steel wood having a hardness of 17.4 PH have been used. Suitably, the hardness of the heads in accordance with the invention is between B60 and C100, preferably C20 to C50, and most preferably C35. The hardness is expressed in the Rockwell Scale, which is a test performed to rank materials for their ability to resist penetration of a diamond indenter pressed into the material.

Suitably, the material has a density between 0.1 and 0.4 lbs/in3, and most preferably between 0.25 and 0.31bs/in3. The modulus of elasticity is preferably between 10 million and 35 million lbs/in2, and preferably between 25 million and 30 million lbs/in2. Suitably, the yield strength is between 50,000 and 200,000 lbs/i*, and preferably between 140,000 and 180,000 lbs/in2. The strength/weight ratio is preferably between 400,000 and 900,000, and preferably between 500,000 and 600,000. Suitably, the moment of inertia is between 0.05 and 2.5, and preferably between 0.07 and 0.09. Suitably, the yield strength is between 50,000 and 200,000 psi, and preferably in the range of 140,000 to 180,000 psi. Finally, the maximum allowable moment is preferably between 15,000 and 130,000 inch lbs, and preferably between 20,000 and 30,000 inch lbs.

In order to actually produce the metal wood with a rod, it has been found that one can simply drill a hole in the sole of the wood, and then place the rod within the hole, and weld the base of the rod to the sole.

In accordance with the invention, the idea can also be applied to iron-type clubs, in addition to wood-type clubs, and an example of an iron mounted with a rod is shown in Figures 4 and 5.

In Figure 4, it will be seen that the rod is mounted horizontally, and in particular, the rod is mounted within the rear cavity of the iron. In Figure 4, the rod is mounted to the toe end of the club. However, the rod could alternatively be mounted to the heel end of the club.

The cavity is preferably provided with a rear face made of metal or plastic materials or such like, in order to"hide"the rod from view for aesthetic considerations. Finally, the rod is mounted behind the sweet spot of the front face of the wood or iron. In particular the outer end of the rod is near the centre of the wood or iron when one looks from the front face of the wood or iron.

In Figure 2, meanwhile, a wood is shown with the tuning rod mounted close the front face of the wood, the tuning fork being mounted in a support ring integral with the base of the wood, the rod being welded to the support ring, the weld being enough to prevent the rod from becoming detached, whilst not being excessive in order to effect the"vibration of the rod", which would happen if there was excess welding.

Finally, whilst the means to provide a sound in the various Figures is a tuning fork, such can be provided by other means, such as, for instance, an electronic chip inlaid in the head, or some other type of electronic means which could cause a sound to be emitted when an object was struck by the golf head.