1. Field of the Invention
The present invention relates to a golf club. In more detail, it relates to a golf club which is improved by arranging a weight, chiefly in the crown section, in order to improve carry.
2. Description of the Related Art
Usually, when teeing off, a golf club called a “driver” is employed in order to achieve a long carry. The carry directly influences the score, so conditions at the impact point on the head of the golf club represent a vital factor. Although the face section i.e. the striking surface is the most important factor, the loft angle is also a factor which cannot be neglected in achieving carry.
In general, if the loft angle is small, the ball flies in a condition closer to the horizontal and a long carry is not usually obtained. On the other hand, if the loft angle is large, the ball flies upwards and in this case also a long carry is not obtained. As described above, the optimum loft angle is set for each club on the basis of experience, though it is also affected by the coefficient of restitution at the position of impact on the face section. Typically, the loft angle is about 11°. The angle of launching of the trajectory of the ball that is struck increases as the loft angle is made larger and, even in this condition, ideally, the golf club should be such as to easily hit the ball in a manner that decreases the amount of backspin.
In order to achieve this, golf clubs are known of a construction facilitating flexing by making the crown section of another material, but they are liable to the formation of cracks. Thus there are various problems concerning golf clubs and various studies have been made. For example, Laid-open Japanese Patent Application No. 11-333037 proposes a golf club in which a weight is disposed at the crown section and the face section, but this does not guarantee an optimum relationship of the speed of backspin rotation and carry. The factors that give a golf ball a long carry are basically three: namely, increasing the initial speed of the ball, the correct amount of backspin, and the correct launching angle. Of these, the coefficient of restitution (C. O. R.) of the face section may be raised in order to increase the initial speed of the ball, but a limit on the coefficient of restitution is imposed by the rules.
On the other hand, the amount of backspin and the launching angle are mutually opposing factors. Ideally, the launching angle is fairly large and the amount of backspin is small, so for example backspin of about 2000 to 3000 rpm is suitable. Even more preferably, the amount of backspin should be as close as possible to 2000 rpm. However, although, in order to obtain a large launching angle, the loft angle suitably tends to be large, as described above, this increases the amount of backspin, giving rise to the problem that the ball rises and hence does not travel far.
As described above, expedients have been adopted in order to increase the carry under various conditions, but the problems have not necessarily been satisfactorily solved. Whereas there are restrictions on increasing the coefficient of restitution in order to achieve a good golf strike, and although, conventionally, the loft angle was increased in order to increase the launching angle, the ideal would be to employ a golf club capable of achieving a long carry by reducing the amount of backspin.
Development of a golf club is therefore desired which, without differing greatly from the conventional shape and without restricting function, should be close to the ideal condition described above, enabling the carry to be extended in a stable fashion.
The present invention was made in view of the prior art described above to achieve the following objects.
An object of the present invention is to provide a golf club wherein impact performance is maintained even if the launching angle is small and in which the amount of backspin is small even if the launching angle is large, by providing a weight in the crown section.
A further object of the present invention is to provide a golf club which is of the same basic shape as conventionally yet wherein impact performance is improved compared with conventionally, by the provision of a weight, towards the inside surface of the crown section, that is offset towards the face section.
Yet a further object of the present invention is to provide a golf club capable of manufacture at low cost.
The present invention adopts the following means in order to achieve the above objects.
According to a first aspect of the present invention, in a golf club comprising: a face section having a striking surface for striking a golf ball arranged at the front face with respect to the striking direction of a hollow metal golf club head; a sole section forming the bottom of said hollow metal golf club head; a crown section forming the top of said hollow metal golf club head; a back section forming the back portion with respect to the striking direction of said hollow metal golf club head; a toe section forming the front of said hollow metal golf club head; and a heel section forming the rear of said hollow metal golf club head, a weight is arranged so as to have a center of gravity near to the face section than a centerline (B) of the width (A) from said face section to the back surface of said crown section, when said golf club is arranged in an address position and projected in the vertical direction.
According to a second aspect of the present invention, in a golf club according to the first aspect of the present invention, said weight is arranged in said crown section.
According to a third aspect of the present invention, in a golf club according to the first or second aspect of the present invention, said weight is arranged in a plurality on the inside surface of said crown section.
According to a fourth aspect of the present invention, in a golf club according to the first or second aspect of the present invention, the loft angle of said hollow metal golf club head is an angle within the limited range of allowed values of the coefficient of restitution and is an angle of 11±2°.
According to a fifth aspect of the present invention, in a golf club according to the first or second aspect of the present invention, the loft angle of said hollow metal golf club head is an angle outside the limited range of allowed values of the coefficient of restitution, and is an angle of more than 15°.
According to a sixth aspect of the present invention, in a golf club according to the first or second aspect of the present invention, said weight is a weight member that is fixed by welding or spray coating on the inside surface of said crown section.
According to a seventh aspect of the present invention, in a golf club according to the first or second aspect of the present invention, said weight includes a weight arranged in one or more locations selected from said sole section, said back section, said toe section and said heel section, other than the weight in said crown section.
According to an eighth aspect of the present invention, in a golf club according to the first or second aspect of the present invention, when said width is 70 to 127 mm, said weight is a weight of 5 to 25 g whose center of gravity is arranged in a position separated by 5 to 60 mm from said face section towards said back surface.
According to a ninth aspect of the present invention, in a golf club according to the seventh aspect of the present invention, said weight comprises weights that are arranged in three locations, namely, said crown section, said sole section and said back section.
According to a tenth aspect of the present invention, in a golf club according to the seventh aspect of the present invention, said weight comprises weights that are arranged in three locations, namely, said crown section, said toe section and said heel section.
According to an eleventh aspect of the present invention, in a golf club according to the ninth aspect of the present invention, when said width is 70 to 127 mm, said weight is a weight of 5 to 25 g whose center of gravity is arranged in a position separated by 5 to 60 mm from said face section towards said back surface.
According to a twelfth aspect of the present invention, in a golf club according to the tenth aspect of the present invention, when said width is 70 to 127 mm, said weight is a weight of 5 to 25 g whose center of gravity is arranged in a position separated by 5 to 60 mm from said face section towards said back surface.
As described in detail above, a golf club according to the present invention is a golf club whereby the amount of backspin can be decreased not only when the loft angle is small but also when the loft angle is large, thanks to the provision of a weight towards the back surface of the crown section, and as a result can achieve a long carry even when the trajectory is low. Also, while the external appearance is the same as conventionally, in comparison with a conventional golf club the cost aspect involves solely addition of a weight. Thus, considering the benefit obtained, low cost is achieved.
FIG. 1 and
The drive club head 1 of this embodiment is a golf club head made of metal with a hollow interior. That is, it is a golf club of the so-called wood type of drivers or fairway woods. The head 1 is of an integral construction; in production, it may be constituted by an individual or a plurality of members which are integrated for example by welding after press forming of the individual members. It comprises five components, namely, the face section 4, sole section 3, crown section 2, hosel 7 and weight.
The back section 3a is the portion between the crown section 2 and sole section 3 and corresponds to the rear of the driver club head 1, being arranged opposite the face section 4. Such a head 1 is obtained by blanking sheet material to the prescribed shape and press forming while heating. After pressing, flash is removed and TIG welding performed. In this embodiment, the material employed is titanium alloy. Regarding the components, the face section 4 and sole section 3 are butted together and then joined with the hosel 7 and the members associated with the pressed crown section 2 are coupled by TIG welding. In this way, an integral driver club head 1 is constituted.
This embodiment is described below in further detail. FIG. 1 and
In this embodiment, the size of this driver club head 1 is indicated by the dimension A from the face section 4 to the back surface 10 of the crown section 2 (or back section 3a). Specifically, the dimension A is the width (see
In this embodiment of the present invention, a weight 8 is provided further towards the face section 4 than this centerline B, in other words, between the face section 4 and the centerline B. As will be described, in the case where a plurality of weights are provided, the center of gravity of the weights as a whole is provided further towards the face section 4 than the centerline B. As this weight 8, a weight member made for example of metal is welded or spray coated at the interior back surface of the crown section 2. It would be possible to provide the weight 8 on the outside surface of the crown section 2, but the external appearance would be adversely affected, so it is preferable to provide the weight at the interior back surface of the crown section.
This weight 8 may be positioned in any position at the wall surface at the interior back surface of the crown section 2, but, as mentioned above, may be provided further towards the face section 4 than the centerline B. Specifically, if the dimension A is 70 to 127 mm, the position of this weight 8 is preferably at an intermediate position separated by about 5 to 60 mm from the face section 4 towards the centerline B i.e. from the face section 4 towards the back surface 10. The weight of the weight 8 is 5 to 25 g.
Also, the weights 8 that are provided at the internal back surface of the crown section 2, apart from a weight directly provided on the inside wall surface of the crown section 2, may include a weight provided at a single or a plurality of locations in the sole section 3 or back section 3a, or in the toe section 5 or heel section 9. Furthermore, when this plurality of weights is provided divided between two or more locations, for example if the weights are provided in the sole section 3 and/or back section 3a, or are provided in the toe section 5 and/or heel section 9, these weights may be arranged so that the center of gravity of this plurality of weights 8 is arranged further towards the face section 4 than the centerline B, even if some of the weights are further towards the back section 3a than the centerline B.
In manufacture of this driver club head 1, the head 1 is finally completed by welding the crown section 2, the weight 8 being provided at the back surface of the crown section 2 prior to this step. There is no restriction on the shape of this weight 8 but, as described above, the weight 8 may be provided in a position such that the position of the center of gravity is shifted further towards the face section 4 than conventionally.
In this embodiment, as shown in
It is also possible to provide a further weight 8a in the vicinity of the centerline B, in addition to this weight 8. Furthermore, although it is possible to provide some of the weights 8 in divided fashion towards the back section 3a within the crown section 2, even if the weights 8 are arranged in this way, the position of the center of gravity of the weights as a whole may be further towards the face section 4 than the centerline B. This applies in the same way even in the case where the weights are provided in the sole section 3 or back section 3a, or in the toe section 5 or heel section 9 in addition to the crown section 2.
Strictly, a plurality of weights may be arranged such that the center of gravity is further towards the face section than the centerline (B) when projected in the vertical direction, with the golf club arranged in the address position with a lie angle of 60°.
The weight 8, constituted by a weight member as shown in
It has been stated that the object of the present invention can be achieved by the provision of weights in other locations in addition to the crown section 2; specific examples thereof will now be described. In addition to the weight in the crown section 2, weights may be provided in at least one or more locations of arrangement in the sole section 3, back section 3a, toe section 5 or heel section 9; examples in which three weights are provided in different locations will be described.
In these embodiments, it was found by a test of hitting that, irrespective of the magnitude of the loft angle, the amount of backspin was decreased and longer carry was obtained. Specifically, the properties of a golf club whose loft angle is less than 15° and which is subject to restrictions regarding the C.O.R. relating to for example the allowed value of the coefficient of restitution, showing a spring effect, and the properties of a golf club of a loft angle of 15° or more are likewise improved.
From the results obtained with the above embodiment, while it is preferable that the loft angle should be about 11°, specifically, 11±2°, even with a loft angle as large as 15° or more, good results are obtained. In this way, a golf club may be realized whereby a suitable amount of backspin is obtained and a good strike can be achieved by increasing the loft angle, compared with conventionally. This is because, for most golfers, it is psychologically more satisfying to be able to view the face section during address, making it easier to strike the ball. The results of hitting are described below with reference to practical examples (test examples), using tables of the data obtained.
Embodiments of improved performance with a construction according to the present invention as described above are described below with reference to data.
FIG. 12 and
Next, the views shown in
When the results are compared with the results obtained in the case of
In all cases, good results were obtained in that good carry was obtained and the amount of backspin was small. Of the three examples, best results were obtained in the case of
According to the results of these tests, with a construction according to the present invention, if the loft angle is 11°, good results are obtained in terms of both carry and backspin, confirming the effect of the present invention. Even if a high loft angle of 15.5° is employed, the amount of backspin is small (less than 3000 rpm), demonstrating the effect of the present invention.
Number | Date | Country | Kind |
---|---|---|---|
2003-046632 | Feb 2003 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
3084940 | Cissel | Apr 1963 | A |
3863932 | Lezatte | Feb 1975 | A |
5076585 | Bouquet | Dec 1991 | A |
5447309 | Vincent | Sep 1995 | A |
5570886 | Rigal et al. | Nov 1996 | A |
5755624 | Helmstetter | May 1998 | A |
6254494 | Hasebe et al. | Jul 2001 | B1 |
6315678 | Teramoto | Nov 2001 | B1 |
Number | Date | Country |
---|---|---|
11-333037 | Dec 1999 | JP |
Number | Date | Country | |
---|---|---|---|
20040166960 A1 | Aug 2004 | US |