GOLF CLUB HOSEL CONSTRUCTION
TECHNICAL FIELD
This invention relates to the construction of golf clubs and the like, and in particular to the manner in which the shaft is attached to the club head. BACKGROUND ART
In my International patent application WO/01578 I described the advantages which may be obtained by reducing the weight of the hosel region, particularly as a result of the redistribution of weight which is then possible. DISCLOSURE OF THE INVENTION
The present invention is directed to the provision of an improved technique for the attachment of a golf club shaft to the club head, which enables the mass of the club head in the region of this connection to be reduced, while providing adequate strength in the connection.
In one broad form presently contemplated, the invention resides in a fitting for the attachment of a hollow shaft to the head of a club or the like, said fitting comprising a first portion the outside dimensions of which correspond substantially with the inside dimensions of the shaft, and a second portion extending beyond the first portion and adapted for fixing within a cavity in said head..
In another aspect the invention resides in means for the attachment of a hollow shaft to the head of a club or the like comprising a fitting dimensioned for adhesive attachment to the shaft end, said fitting comprising at least one longitudinally extending rib means engaging within a complementarily shaped groove means in the head of said club.
BRIEF DESCRIPTION OF THE DRAWINGS
To facilitate an understanding of the invention, a presently proposed embodiment thereof will now be described by way of example only, in relation to the accompanying drawings, in which :
Fig. 1 is a cross-sectional elevation of a hosel
fitting incorporating the present invention; Fig. 2 is a fragmentary cross-sectional elevation of a golf club head assembly incorporating the hosel fitting of Fig. 1; Fig. 3 is a section taken on the line 3-3 of Fig. 1; and Fig. 4 is a fragmentary cross-sectional elevation of a hosel fitting in a wood club head. MODES OF CARRYING OUT THE INVENTION The club head assembly shown in the accompanying drawings comprises a hosel fitting 10 of cylindrical configuration, comprising an upper sleeve portion 11 and a concentric lower sleeve portion 12 of reduced diameter. The upper sleeve portion 11 is dimensioned to provide a close fit within the lower end of the club shaft 13, and is provided with an outwardly extending peripheral flange 14, the outside diameter of which corresponds with the outside diameter of the shaft 13.
Extending over the length of the lower sleeve portion 12 is a longitudinal rib 20, which is provided for the purpose of increasing the rotational security of the fitting within the club head, as referred to further below.
As shown in Fig. 2, the hosel fitting 10 is dimensioned for reception within the hosel 15 of the club head, the hosel region being for this purpose provided with a bore having an upper portion 16 the diameter of which provides a close fit for the shaft 13, and a lower section 17 the diameter of which enables a force fit of the portion 12 of the hosel fitting 10, with the flange 14 and the shoulder 18 formed by the step between the two diameters of the fitting 10, seated on a shoulder 19.
The lower bore section 17 is provided with a longitudinal slot 21 extending over its entire length, dimensioned and shaped for the reception of the rib 20. The engagement of the rib 20 within the slot 21, greatly assists in ensuring the security of the bond between the hosel fitting and the club head, against the effects of
the rotational forces encountered at impact.
While the manner by which the components of the assembly are fixed together is a matter of choice, a suitable approach will be to bond the fitting 10 within the shaft 13 by means of a suitable adhesive, and similarly to employ adhesive bonding of the end of the shaft 13 within the upper portion 16 of the bore in the hosel 15. The lower section 12 of the fitting 10 may be force bonded with the bore section 17, or again adhesive may be used. If desired, a space 22 may be provided between the foot of the portion 12 and the lower end of the bore 17, and this space may be filled with a suitable material or by other
to provide a pleasing finish to the club head in this region. The effect of such an arrangement will be that the entire hosel area becomes a unified structure of great strength, particularly as a result of the fact that both surfaces of the shaft wall are bonded, providing much greater strength than that of conventional construction where only one surface of the shaft wall is bonded, either to an inner spigot or to an external sleeve.
A modified version of the present invention is illustrated in Fig. 4, for the case of a wood club head. In this form of the invention, a sleeve 23 is fitted from below, into a bore 24 in the club head, the inside diameter of the sleeve 23 providing a close fit for the shaft 13.
The rib 20 is fitted within a correspondingly dimensioned slot cut in the wood of the club head, and the lower end of the bore 24 is closed by the sole plate 25 which also presses the fitting 23 against an upper end 26 of the bore 14. The fitting 23 is fixed within the club head preferably by means of a suitable high strength adhesive. After the fitting 23 has been fixed within the club head, the shaft 13 is introduced through the bore 16, and again preferably a high strength adhesive is used to fix the shaft within the fitting 23 and within the head.
As a result of the use of this approach to the fixing of the shaft within a wooden club head, the hosel region 15 of the head is relatively short, and for aesthetic purposes may be continued by a false hosel 27 of lightweight material which need not have any structural function. This false hosel may be provided with the binding which is traditional for wooden club heads, so that the appearance of the head will be traditional.
As a consequence of the strength achieved by the use of a hosel fitting of the kind described, the weight of the hosel portion of the club head may be reduced without sacrificing strength in this region, and in fact significant weight reduction can be achieved while obtaining increased strength compared with conventionally built clubs.
This weight reduction has several important consequences. Firstly, the mass of the club head may more readily be located symmetrically in relation to the centre of percussion of the head, thereby reducing the tendency of the club head upon impact to skew from the correct alignment in relation to the path of the swing. Secondly, the mass of the club as a whole may be redistributed to modify the. dynamic behaviour of the club in order to improve the efficiency of the golf swing. Thus, for example, part of the saving in mass in the hosel region can be used to increase the mass of the head in the striking region of the club head, while the remainder of the mass saving can be relocated in the region of the grip for the purpose of adjusting the balance and feel of the club. In this way a significant increase in positive weight sensation can be provided for the strong player, with a negligible increase in dead weight of the club.
Alternatively, a smaller proportion of the saved mass may be relocated to the head, and a larger proportion to the grip area, providing a more neutral feel which will enable the weaker player to concentrate on his swing, rather than on control of the head.
It will be appreciated that the weight saving obtained may be redistributed in other ways, and may for example be used entirely for altering the balance of the club or reducing the overall weight of the club. A further consequence of the weight saving in the hosel region, lies in the effect of this on the choice and design of shaft. With reduction of head mass by 15 - 18% as a result of the reduction of the mass of the hosel region, a "regular" shaft will behave in the manner of a stiffer shaft, approximately an XX stiffness shaft, and of course few golfers are strong enough to use a shaft of this stiffness. A significantly lighter shaft may now be employed in view of the reduced lever end loadings, and this weight saving in the shaft may be employed to produce an overall weight saving and to facilitate the redistribution of weight described above.
A further advantage which flows from the reduction in mass of the hosel region possible with the present invention, arises from the consequent reduction in size of this region. Because the hosel region is so small, it no longer intrudes on the visual field of the golfer, so that the club head, viewed from above, looks larger and longer than it really is. Furthermore, the mass can better be concentrated about the "sweet spot" on the face, and the head may be shorter and lower in profile than is conventional.
Specific advantages also flow from the application of the invention to wooden club heads in the manner described above. Because a long hosel is no longer required, the head block from which the head is machined can now be much smaller, and it may be possible to cut two or even three heads from the same block size currently required for the production of one head. Where expensive timber such as persimmon is used, this represents a significant saving in material cost. This reduction in the amount of machining required has the further advantage of reduced cost in tools and tool maintenance, and will facilitate the employment of timber such as Australian hardwoods, since
the reduced amount of cutting required will mitigate the disadvantage of these timbers in the greater rate of wear of tools when working with them.
While the present invention has been described herein in relation to specific examples, it will be appreciated that it is capable of embodiment in other forms, and the scope of the invention is not to be regarded as limited by the particularity of the preceding description. For example, the longitudinal rib and slot which have been described may be replaced by splines, or by other shaping of the hosel fitting and club head bore, or of the shaft end. In a further modification in the application of the invention to iron club heads, the tip of the shaft may be provided, for example by casting, with an internal rib or other internal formation engaging with a complementary formation on the portion of the hosel fitting which enters the shaft tip.