IMPROVEMENTS IN GOLF CLUBS

This invention relates to golf clubs and, in particular, provides a shock-absorbing insert for insertion into the grip end of a golf club shaft, a shock-absorbing insert for insertion into the grip end of a golf club shaft.

BACKGROUND TO THE INVENTION

All golfers are searching for ways to increase the distance that they can hit a golf ball using a particular club.

High handicap golfers frequently mishit the ball and in so doing hit the ground with consequent jarring of their hands, wrists and/or elbows which can lead to injuries such as, for example bursitis.

A means of alleviating the jarring effects of mishit shots and of allowing golfers to hit the ball greater distances would be of great benefit to golfers.

SUMMARY OF THE INVENTION

This invention provides an insert for insertion into the grip end of the shaft of a golf club and which is to be covered with a conventional grip, which provides a shock- absorbing effect and also changes the resilience of the shaft providing a higher clubhead speed thereby allowing the ball to be hit further than with an unmodified club.

According to the invention a shock-absorbing insert for insertion into the grip end of a golf club shaft comprises a plug comprising an outer body of resilient material having generally the same diameter as the grip end of the shaft of a golf club, the resilient material encompassing an elongate stiffening element of higher rigidity than

that of the golf club shaft with which it is to be used and running at least the entire length of the plug.

The resilient material will normally be a relatively hard natural or synthetic rubber of IRHD hardness between 60 and 90, more preferably about 80, and may, for example, be a nitryl-butadiene rubber of such IHRD hardness.

The stiffening element may, for example, be a tubular element and may, in fact, be a section of golf club shaft providing that it is stiffer than the remainder of the shaft. Preferably, however, the stiffening element comprises a strip of resilient material, for example, spring steel, having a rectangular section with its width greater than its thickness.

The plug is preferably tapered in the manner of a conventional golf club shaft and is preferably formed with a narrower portion at one end for fitting into the shaft. Since golf club shafts vary somewhat in their dimensions, the plug will normally be made a bit larger than the greatest shaft diameter so that it can be tailored to fit any particular shaft by removing surplus material. This is particularly so when the insert is to be retro-fitted since it will not be known prior to fitting what the diameter of the insert end of the plug should be.

Typically the resilient elastomeric material will have a length of about 130 to 170, preferably about 150, mm with a narrower part length about 1/3 of the overall length. The smallest diameter will usually be about 12 mm and the largest diameter about 15 mm. The stiffener element may have a length up to about 5 to 10 mm greater than that of the elastomeric material. When the stiffener element is a strip of material it preferably has a width of about 9 mm and a height about 3 to 6 mm.

The insert may be incorporated into a club during manufacture or be retro-fitted. In the latter case it will usually be necessary to cut off a length of existing shaft approximately equal to the length of the wider end of the insert.

As manufactured the stiffener element preferably protrudes somewhat beyond the larger end of the resilient material so that during insertion of the insert the protruding end can be gripped to allow the insert to be rotated to a desired orientation.

For fitting the insert, the length of the shaft of the club is, if necessary, first adjusted by removing an unwanted portion. The narrower end of the insert is then tailored to fit snugly inside the shaft, inserted and fixed immovably in position. When the stiffener element is a strip, before fixing it in position, the insert will usually be adjusted to a position in which the width of the strip lies substantially parallel to the leading edge of the sole of the club by turning it using a protruding end of the stiffener element. The protruding end may then be removed. The golf club grip is then slid over the insert and a part of the shaft of the club in the normal manner.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which

Fig. 1 is an end view of one form of insert according to the invention;

Fig. 2 is a section through the insert of Fig. 1; and Fig. 3 is an isometric view of the insert of Figs. 1 and 2.

As shown in the drawings, the insert comprises a body 1 of nitryl-butadiene rubber of IHRD hardness about 80 having a narrow end 2 and a wider end 3 separated by a step 4. The overall length of body 1 is 150 mm while the diameters of narrow end 2 and wider end 3 are 12mm and 15 mm, respectively. Encompassed within body 1 is a stiffener element in the form of a rectangular strip 5 of spring steel having a long side 6 of length of 150 mm, a second side 7 with a width of 9 mm and a third side 8

of width 3 mm. Depending on the degree of flex desired in the stiffeher strip its height may vary between 3 and 6 mm.

The insert provides a number of advantages. First, the resilience of the body of the insert gives a soft feel and greatly reduces the jarring effect on the hands and arms when a golfer hits the ground or other hard surface. Moreover, the clubs are very forgiving and even a mishit shot will go further than a similar shot played with the same club without the insert. There also seems to be a slice reducing effect although a hooked shot is not affected. Secondly, the presence of the stiffener element means that the rigidity of the club at the grip end is higher than that at the head end so that greater clubhead speed is generated. Thirdly, the weight of the insert has an effect on the balance of the club so that it is easier to swing.