Golf club wood head

Abstract

A metallic golf club wood head comprises a substantially planar face member welded to a container-shaped rear shell member having an open front face. A shaft connecting portion 7a is forged integrally with an upper portion of the face member 11a. A cut-out 14a is formed in an upper face of a front side of a rear shell member 12a for accommodating a lower portion of the shaft connecting portion 7a. As a result of this construction the number of structural members is reduced and the strength of the shaft connecting portion 7a is increased. Furthermore, the loft angle can be adjusted when manufacturing the face member 11a for example by forging. Moreover, since it is sufficient for the shaft connecting portion 7a to be formed at the top of the head only, the front side of the head can be lightened and the "sweet area" increased.

Description

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a hollow metallic golf club head of the so-called "wood" head type.

(b) Description of the Prior Art

Golf club wood heads having a hollow metallic head body as disclosed for example in Japanese Unexamined Patent Publication No. 63-154186 are known, and are referred to as "metal woods". With the head disclosed in this publication, the head body is constructed by welding together two or three forged shell members. The divisions may be for example into three sections, namely a face, sole, toe, and heel section, a back section, and a top section, or into two sections, namely a front section and rear section formed by a dividing line between sole, toe, heel, and top portions. A shaft connection pipe for connecting a separate shaft to the shell member is fixed to the shell member by welding. In fixing the shaft connection pipe, the lower end is inserted to abut against the sole of the shell member.

Since this construction of the head involves connecting together two or three shell members as well as the shaft connection pipe, the large number of components means that the number of operations such as welding required in the manufacturing process becomes large so that costs are increased. Moreover, since the shaft connection pipe is a separate body, the strength of the shaft connection can also be a problem. Furthermore, the shaft connection pipe which protrudes in an upward direction from the top of the head has its lower end extending as far as the sole. Hence the weight of the front side of the head is increased by the shaft connection pipe. This increase in weight of the front side of the head, reduces the "sweet area". Here "sweet area" refers to a region on the face where a ball that is struck by this region flies stably and directly ahead. The "sweet area" can be increased by moving the overall center of gravity of the head further rearward (lowering the center of gravity).

With Japanese Utility Model Unexamined Publication No. 58-185252, although an iron club head is disclosed and not a wood club head, there is disclosed a container-shaped balance weight having an open front face connected to a rear face of a substantially planar face member which is formed integrally with a shaft connecting portion. The connection face of the face member and the balance weight is a planar face. With a construction such as that of this disclosure, the head is formed as two members, so that the number of members is reduced. However, since the positional relationship between the face and shaft for the iron club head differs from that for the wood club head, the construction disclosed in this publication cannot be applied as is to the wood club head.

With the conventional hollow metallic golf club wood head as described beforehand, the head body construction involves welding together the two or three shell members and the separate shaft connection pipe. Due to the large number of members, the number of operations in the manufacturing process becomes large, so that costs are increased. Moreover there can be problems due to the strength of the shaft connection being weak. Furthermore, since the lower end of the shaft connecting pipe extends as far as the sole, the weight of the front side of the head is increased, thus reducing the "sweet area".

SUMMARY OF THE INVENTION

The present invention addresses the above-mentioned problems and has as a primary object to provide a golf club wood head of fewer structural members, thus enabling a reduction in the number of manufacturing operations and a reduction in cost, and wherein the strength at the shaft connecting portion can be increased, the loft angle can be easily adjusted in manufacture, and which can have a lower center of gravity. It is a second object of the present invention to provide a golf club wood head wherein the structural members thereof can be easily connected together. It is yet a third object of the present invention to provide a golf club wood head wherein the weight distribution of the head can be easily set.

According to a first aspect of the invention directed towards achieving the primary object, there is provided a golf club wood head having a hollow metallic body with a face on a front surface thereof and a shaft connecting portion protruding upward from an upper portion of a heel side, the head comprising a substantially planar face member, and a container-shaped rear shell member having an open front face connected to a rear side of the face member, wherein the shaft connecting portion is integrally formed with the face member on an upper portion of a heel side thereof and protruding rearward therefrom, while a cut-out is formed in the rear shell member in a heel side on an upper face of a front side, for accommodating a lower portion of the shaft connecting portion formed on the face member.

According to a second aspect of the invention directed towards achieving the second object, a separate lower rear side part of the shaft connecting portion is formed on the rear shell member.

According to a third aspect of the invention directed towards achieving the third object, a recess is formed in a rear face of the face member.

The golf club wood head according to the first aspect of the invention is constructed with a container-shaped rear shell member connected to a rear side of a substantially planar face member, and a shaft connected to a shaft connecting portion which is formed integral with the face member. The shaft connecting portion is formed on an upper portion of the face member and protruding rearward therefrom, and when connecting the rear shell member to the face member, fits into the cut-out portion on the upper face on the front side of the rear shell member. The face member and the shaft connecting portion are thus formed in this way as a single unit. Since the face member is also of a simple planar shape, then when manufacturing for example by forging, the loft angle can be easily adjusted. Moreover, since the shaft connecting portion is at the top of the face member but not at the bottom, the front side of the head can be lightened. As a result, the center of gravity can be lowered and the "sweet area" increased.

With the golf club wood head according to the second aspect of the invention, the separate lower rear side part of the shaft connecting portion is formed on the rear shell member, and the connection line between the face member and the rear shell member is made as straight as possible. As a result, joining such as by welding can be carried out easily.

With the golf club wood head according to the third aspect of the invention, a recess is formed in a rear face of the face member. The weight distribution on the face side can thus be set by setting the location and size of the recess. For example, if the recess is located towards the heel side, the weight distribution of the head is off-set towards the toe side, giving a golf club suitable for a player who tends to slice. On the other hand, if the recess is located towards the toe side, the weight distribution of the head is off-set towards the heel side, giving a golf club suitable for a player who tends to hook.

Other objects, features and advantages of the invention will become apparent to those skilled in the art from the following description of the preferred embodiments of the invention, wherein reference is made to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a first embodiment of a golf club wood head of the invention;

FIG. 2 is a perspective view of a rear side of a face member of the first embodiment;

FIG. 3 is a perspective view of the manufactured overall head of the first embodiment;

FIG. 4 is a cross-sectional view of the manufactured overall head of the first embodiment;

FIG. 5 is a rear view of a face member of a second embodiment of a golf club wood head of the invention;

FIG. 6 is a rear view of a face member of a third embodiment of a golf club wood head of the invention;

FIG. 7 is a rear view of a face member of a fourth embodiment of a golf club wood head of the invention; and

FIG. 8 is an exploded perspective view of a fifth embodiment of a golf club wood head of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As follows is a description of a first embodiment of a golf club wood head according to the present invention with reference to FIG. 1 through FIG. 4. The golf club wood head of this embodiment is hollow and made of a metallic material. For the metal a variety of metals may be used such as pure titanium, titanium alloy (with a specific gravity of approximately 4.6), stainless steel, or some other light weight alloys. In the figures, reference numeral la designates the face of a front side, 2a the back of a rear side, 3a the sole of a bottom side, 4a the top of an upper side, 5a the toe on one side, and 6a the heel on an other side. Extending upward from the heel 6a side is a tubular shaped shaft connecting portion (hosel) 7a to which is connected a shaft 8a. A lower portion of an outer peripheral face of the shaft connecting portion 7a comprises a curved face 9a formed so as to blend smoothly with the top 4a, the face 1a and the heel 6a, while a through-hole 10a for receiving for example a connecting portion of the shaft 8a, is formed in the shaft connecting portion 7a.

The head body is divided into two parts; a substantially planar face member 11a having the face la and the shaft connecting portion 7a; and an open faced container-shaped rear shell member 12a having the other portions of the head. The head body is constructed by welding the rear shell member 12a to the rear side of the face member 11a. The upwardly protruding shaft connecting portion 7a is integrally formed on the upper portion of the heel 6a side of the face member 11a and protruding rearward therefrom, while a cut-out 14a is formed in the rear shell member 12 a in the heel 6 a side on the upper face of the front side thereof. This cut-out 14a accommodates a base portion 13a at the lower side of the shaft connecting portion 7a formed on the face member 11a. The rear surface of the face member 11a with the exception of the periphery, is formed with a recessed portion 15a.

The face member 11a including the shaft connecting portion 7a, and the rear shell member 12a are basically fabricated by die-forging. However, parts such as the through-hole 10a in the shaft connecting portion 7a, can for example be machined after forging as necessary. Furthermore, the rear shell member 12a may have undercut configurations in optional directions. However even with a rear shell member 12a having such a configuration, this can be formed without problems by multistage die-forging.

The face member 11a and the rear shell member 12a thus fabricated are then welded together. At this time, the base 13a of the shaft connecting portion 7a formed on the face member 11a is fitted into the cut-out 14a provided in the rear shell member 12a. After welding the face member 11a to the rear shell member 12a, a filler such as foamed urethane may be introduced as necessary into the head via the through-hole 10a in the shaft connecting portion 7a. After this the shaft 8a is connected to the shaft connecting portion 7a.

With the construction of the above-mentioned embodiment, the head body comprises two members: the face member 11a including the shaft connecting portion 7a; and the rear shell member 12a. The number of members can thus be reduced so that the number of operations in the manufacturing process can be minimized with a saving in costs. Furthermore, since the shaft connecting portion 7a is integrally formed with the face member 11a, the strength of the shaft connecting portion 7a can be increased compared to welding a separate member to the face member 11a. Hence the connection strength of the shaft 8a can be increased, Moreover, since the face member 11a needs to be stronger than the other parts, necessitating the comparatively large thickness thereof, then as well as increasing the strength of the shaft connecting portion 7a there is the further advantage of increased strength of the face member 11a.

Although the strength of the shaft connecting portion 7a is ensured in the above manner, it should be noted that the shaft connecting portion 7a only extends to the upper portion of the face member 11a, and not to the lower portion, which enables the lightening of the front side of the overall golf club head. Accordingly, the rear side of the overall head can be weighted, corresponding to the lightening of the front side. As a result the center of gravity of the overall head can be lowered, thereby enlarging the sweet area. In this respect, the rear portion inside the rear shell member 12a may be integrally formed with a weight, or else a separate weight may be welded thereto.

With the above construction, a loft angle (that is, the angle of the face 1a to a vertical plane) can also be adjusted by the angle-setting of the shaft connecting portion 7a to the face 1a, and since the face member 11a is a simple planar shape, then this setting can be easily and correctly attained during manufacture. In this respect, the adjustment of the loft angle with respect to the face member 11a can be performed at each stage of a plurality of forging processes. In addition, after the forging process, a sizing process may be performed using a sizing press to give the final configuration and size of the face member 11a. In this sizing process also, the loft angle may be adjusted. Moreover, since the face member 11a is of a simple planar form, the loft angle can be adjusted by shaving off the front edge 16a of the upper or side surface of the rear shell member 12a as shown by the chain line in FIG. 4, using a machine such as a laser beam machine. Being able to adjust the loft angle in this way by a number of operations during manufacture is also advantageous for the accurate setting of the loft angle.

Furthermore, since the rear surface of the face member 11a, with the exception of the periphery, is formed with the recessed portion 15a, the weight distribution of the head is more concentrated around the periphery of the face 1a, so that the "sweet area" is enlarged.

Additionally, when forming the recess on the rear face of the face member, for example by forging, the number, size, location or depth of the recesses can be optionally and easily chosen, thus enabling the easy and optional setting of the weight distribution at the face side of the golf club head depending on the above choice.

In this respect second, third and fourth embodiments will now be described with reference to FIG. 5 through FIG. 7. In FIG. 5, FIG. 6, and FIG. 7 components corresponding to the components of the first embodiment are indicated by the same numerals with respective suffixes "b", "c", "d" added. Similarly in FIG. 8 to be discussed later in relation to a fifth embodiment, suffix "e" is added.

In the second embodiment shown in FIG. 5, the heel 6b side of the rear face of the face member 11b is formed with a recess 15b. Whereas, in the third embodiment shown in FIG. 6, a toe 5c side of the rear face of the face member 11c is formed with a recess 15c. Furthermore, in the fourth embodiment shown in FIG. 7, the upper side of the rear face of the face member 11d is formed with a recess 15d.

If as in the second embodiment, the recess 15b is located towards the heel 6b side, the weight distribution of the head is off-set towards the toe 5b side, giving a golf club suitable for a player who tends to slice. On the other hand, if as in the third embodiment the recess 15c is located towards the toe 5c side, the weight distribution of the head is off-set towards the heel 6c side, giving a golf club suitable for a player who tends to hook. Furthermore, if as in the fourth embodiment the recess 15d is located towards the top, the center of gravity can be further lowered thus helping to lift the ball giving an increase in range.

In FIG. 8, showing the fifth embodiment of the golf club wood head of the present invention, most parts of the shaft connecting portion 7e are still integrally formed on the face member 11e. However, a lower rear side 17e of the shaft connecting portion 7e is integrally formed on the rear shell member 12e in addition to the cut-out 14e for accommodating the lower portion of the shaft connecting portion 7e formed on the face member 11e side. As a result, the line of abutment of the face member 11e with the rear shell member 12e will be approximately a straight line or a plane, thereby simplifying the welding of the face member 11e to the rear shell member 12e. The lower rear side 17e of the shaft connecting portion 7e may be integrally formed on the rear shell member 12e at the time of forging, or may be formed as cladding at the time of welding.

The present invention is not limited to the before-mentioned embodiments, but also encompasses various modifications. For example with the before-mentioned embodiments, both the face member and the rear shell member were forged. However, either one or both may be forged. Moreover, with the before-mentioned embodiments, the hole in the shaft connecting portion for connection of the shaft is formed as a through-hole. However, this hole need not necessarily pass right through.

With the first aspect of the invention, the wood club head is constructed with a container-shaped rear shell member having an open front face connected to a rear side of a substantially planar face member. The shaft connecting portion is integrally formed with the face member on an upper portion of a heel side thereof and protruding rearward therefrom, while a cut-out is formed in the rear shell member in the heel side of the front side upper face, for accommodating a lower portion of the shaft connecting portion formed on the face member. As a result the number of structural members can be reduced, giving a reduction in the number of manufacturing operations and a reduction in cost. Furthermore, since the shaft connecting portion is integrally formed on the face member, the strength of the shaft connecting portion can be increased, and since the face member is of simple planar form, it can be manufactured for example by forging, and the loft angle can be easily adjusted. In addition, since the design is such that the shaft connecting portion need only be provided on the upper portion of the face member, the front side of the head can be lightened, and the center of gravity can be lowered, thereby enlarging the sweet area.

With the second aspect of the invention, since the lower rear side part of the shaft connecting portion is formed on the rear shell member, the line of abutment of the face member with the rear shell member will be approximately a straight line or a plane, thereby simplifying the joining, by welding and the like, of the face member to the rear shell member.

With the third aspect of the invention, a recess is formed in a rear face of the face member, thus facilitating the setting of the weight distribution of the head.

Claims

1. A golf club wood head having a hollow metallic body with a face on a front surface thereof and a shaft connecting portion protruding upward from an upper portion of a heel side, said head comprising: a substantially planar face member, and a container-shaped rear shell member having an open front face connected to a rear side of the face member, wherein said shaft connecting portion is integrally formed with said face member on an upper portion of a heel side thereof and protruding rearward therefrom, while a cut-out is formed in said rear shell member in a heel side on an upper face of a front side thereof, for accommodating a lower portion of the shaft connecting portion formed on said face member.

2. A golf club wood head as claimed in claim 1, wherein a separate lower rear side part of said shaft connecting portion is formed on said rear shell member.

3. A golf club wood head as claimed in either of claim 1 and claim 2, wherein a recess is formed in a rear face of said face member.