Putters typically have a loft of 6" or less.

Background Art At present, golf 'woods' (which includes 'drivers') are made of wood or other suitable materials, often with inserts of different materials in the striking face. Golf 'irons' are made of metal, and until 1990, international golf regulations did not permit the use of inserts in irons. Inserts in irons are now permitted.

Typical insert materials for both woods and irons are graphite, ceramics, and titanium.

Woods and irons made of, or faced with, softer materials such as wood are preferred by players, because the clubs are capable of absorbing more of the shock when the club strikes the ball, and hence feel 'softer' to the player.

However, softer materials simply do not have the required strength to take the impact forces of the club on the ball without damage, and as golf balls have tended to increase in hardness over recent years, it has become necessary for manufacturers to use harder materials for woods and irons (and their inserts) to avoid breakage.

It is therefore an object of the present invention to provide a golf wood or iron with an insert which, although hard and tough, is nevertheless shock- absorbent and capable of giving a 'soft' feel to the club in use.

Disclosure of the Invention Unexpectedly, the applicants have discovered that jade combines these desirable properties. This is surprising, in that jade is the toughest known mineral and is known to be extremely hard (approximately 6.5-7 on the Moh hardness scale). Jade therefore would have been expected to give a hard and non-absorbent feel to a golf club. However, the applicants have discovered that the crystalline structure of jade is such that jade effectively acts as if it were a fibrous material, and thus is capable of providing a very hard insert with a 'soft' feel. As used herein, the term 'jade' means nephrite or jadeite.

The long monoclinic crystals of jade characteristically are formed like closely felted fibres - the greater the degree of felting, the tougher the jade. In addition, jade is very dense: jadeite typically has a specific gravity of 3.3 - 3.5, nephrite a specific gravity of 3.1 - 3.3.

It is known to make golf putters with heads wholly of jade, or with decorative jade face inserts, but this is for novelty or decorative purposes only, and has no functional advantage or value. Indeed, putters require a softer face and do not need the hardness necessary to propel the ball iong distances, which woods and irons require.

The present invention provides a golf club designed to provide a loft of a least 7°, wherein a major portion of the striking face of the club comprises a sheet of jade.

The present invention further provides a method of making a golf club which is designed to provide a loft of at least 7°, said method including the steps of: ( 1 ) providing a golf club head; (2) forming in said head a recess which covers a major portion of the striking face of said club; (3) providing a sheet of jade dimensioned in length and width to fit said recess and having a thickness greater than the depth of said recess; (4) forming a plurality of indented keys on one face of said sheet of jade; and (5) securing said sheet of jade into said recess with said keyed surface inwards.

The sheet may be secured in the recess using any suitable glue e.g.

An epoxy resin glue.

The outer face of the sheet may be ground to any of a range of desired finished shapes, then polished, and grooved if required.

Preferably, the jade sheet has a thickness of between 4 and 8 mm.

Brief Description of the Drawings

By way of example only, a preferred embodiment of the present invention is described in detail with reference to the accompanying drawings, in which:- Fig. 1 is an isometric view of a golf club head in accordance with the present invention; Fig. 2 is a plan view of the rear face of the insert; and Fig. 3 is a section on line 3-3 of Fig.2.

Best Mode for Carrying Out the Invention Referring to the drawings, a golf club in the form of a driver 2 comprises a head 3, a shaft socket 4, and a shaft (not shown). The head 3 may be any of a range of shapes, and may be made of any suitable material e.g. Aluminium alloy, graphite, or suitable plastics material.

The striking face of the club is formed from an inserted sheet of jade 5 secured into a recess 6 formed in that face of the club. The recess 6 is formed in the club when the club head is made, or is machined out afterwards. The recess 6 occupies a major part of the striking face of the club, with only a thin rim 7 of the original club face around the recess. The recess is depicted as an irregular ellipse, but in fact may be of any desired shape. The depth of the recess is slightly less than the thickness of the insert 5.

The insert 5 is cut from a sheet of high-grade nephrite jade, at a predetermined angle to the grain of the mineral. The insert is cut approximately 10 mm thick, and is shaped to fit the recess in length and width.

As shown in Fig. 2, the rear surface of the insert is formed with a plurality of semi-circular cut-outs 8 which form keys. The cut-outs 8 are angled (see Fig. 3) and extend between 1.5 and 2.5 mm into the thickness of the insert.

The insert 5 is secured to the recess 6 by spreading a suitable glue (e.g. Epoxy resin) over the keyed surface of the insert, working the glue well into the keys 8, and over the surface of the recess 6. The insert 5 is then placed in the recess, initially being placed at a slight angle, to allow any trapped air to be expelled. The insert is positioned so as to be in register with the recess and completely fills the recess. Excess glue is wiped away. The insert is then pressed into place until the glue sets.

The insert 5 now forms substantially the whole of the striking face of the club. The insert 5 is finished by grinding the outer surface of the insert to give the bulge and roll required by the customer:- typically the outer face of the insert is outwardly convex.. The outer face is then polished and may also be grooved. The jade usually is worked with diamond cutting and/or grinding tools.

The jade can be finished to a high degree of accuracy and the user's particular requirements can be catered for much more readily than with a conventional metal club. The insert can be finished to produce a very wide range of loft, lie, bulge and roll characteristics.

The finished insert typically is about 6.5 mm thick for irons and about 7.0 mm thick for divers, At these thicknesses, the jade is very strong and

tough and stands up to heavy use.

Because of the high density of jade, the finished club is front-weighted, which gives improved ball flight characteristics. This weight of the remainder of the club generally is reduced, to compensate for the weight of the insert, so that the completed club remains within the approved weight limits. It will be appreciated that the head must be designed so that the recess into which the insert is fitted gives solid, continuous support for the insert.

If the insert is too thick, the high density of the jade makes the club too heavy; the maximum practical thickness of the insert is about 8 mm. If the insert is too thin, there is a risk it will crack or split. The minimum thickness is about 4 mm.