Golf club

Abstract

A golf club which comprises a head which is less deformable by the heat in welding. Separate reinforcing members 12 and 13 are provided on inner surface of a front edge 8A of a crown shell 8. Thus, the front edge 8A side is thickened and then the upper edge 4A of the face shell 4 is joined to the front edge 8A of the crown shell 8, by welding. The front edge 8A of the crown shell 8 is formed with a plurality of projections 11 which are anchored by the upper edge 4A of the face shell 4. front edge 8A of the crown shell 8 is thickened by adding the thickness of the reinforcing members 12, 13 to the thickness of crown shell 8 itself. Thus, thermal deformation and the sinking of the front edge 8A at the time of welding can be prevented, thus enabling the upper edge 4A to be joined to the front edge 8A as designed.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a golf club with a head made of a plurality of separate shells, having a shaft connected thereto.

[0003] 2. Description of the Prior Art

[0004] Conventionally, in order to produce wood golf club heads or so-called “metal Wood”, it is known art to join a plurality of metallic shells together. In those types of heads, respective peripheries of plural metallic shells are integrally welded to one another.

[0005] As golf club heads are progressively large-sized, with lower centers of gravity thereof being pursued, respective separate shells for constructing a head also are getting thinner and thinner. For example, in the case that a beta titanium alloy is used, face is normally as thin as 2.5 to 3.0 mm, sole and crown are each as thin as 1 mm or below. When welding such thin separate shell together, there occurs a problem that heat by the welding causes deformation. More specifically, when welding a crown to a face, a front edge of the crown is likely to sink toward the inside. In that case, excessive grinding would be needed as a post-processing to obtain a predetermined configuration, so that the resultant thickness of welded portions becomes too small. As a result, a golf club head thus produced is likely to become irresistible to impact at the time of striking balls, resulting to a likelihood to cause cracks therein.

[0006] On the other hand, while the peripheral edges of a plurality of metallic shells are welded together in metal wood golf clubs, welding is performed by abutting the adjacent peripheral edges to one another, so that there is another problem that an excessive amount of welding bead enters inside. While welding bead is to be heaped up in an approximately even manner along the welding advancing direction, if a portion of the welding bead sinks into the inside, then the portion is depressed, and thus another welding bead must be heaped up again. If beads are repeatedly heaped up this way, more welding heat is applied due to the welding, so that the undesirable deformation is more likely to occur. On the other hand, if the excessive welding bead is heaped, then it would be difficult to visually confirm the configuration of parts where respective shells are joined. Further, there would occur a further problem that the applied heat causes a change in strength property of titanium alloy material so that the fragility is increased, thus leading to the possible destruction of the neighborhood of the parts to bewelded. Even though non-solution treatment material is used, yet the welding bead is likely to cause deformation to some extent.

[0007] Whereas, in paragraphs 0008 to 00010 in Japanese Un-Examined patent publication No 11-114106 is disclosed a method for manufacturing a golf club, wherein in a golf club head comprising a hollow metallic body shell and a face shell joined to an opening of said body shell which is open to the face shell, at least one of an end face of the opening of the body shell or an edge of the face shell is formed with a plurality of projections to be abutted to the other, while beads 15 are buried in recesses formed between the projections, to fix the face shell to the opening of the body shell; and also a method for manufacturing a golf club wherein a welding member is heated while being abutted to the recesses formed between the above projections when abutting the face shell to the head body, so that the welding member is fused to be filled in said recesses, to thereby fix the face shell to the opening of the head body. The prior art teaches that such methods ensure beads to be properly positioned in the recesses between the projections in a position where the body shell and the face shell are joined, without overlapping with the body shell or the face shell, so that the face shell is lightened.

[0008] According to the prior art, however, there still remains a problem that when joining respective thin separate shells together by welding, they are deformed due to the heat in welding. Further, the prior art involves a further problem that as one of the members to be abutted is provided with projections, and beads are buried in recesses formed between the projections, excessive amount of welding beads is likely to enter the inside through the recesses.

SUMMARY OF THE INVENTION

[0009] To eliminate the above problems, it is, therefore, a main object of the present invention to provide a golf club having a head constructed by joining a plurality of metallic shells, and a shaft connected to the head, wherein said head is less likely to be deformed by the heat in welding.

[0010] It is another object of the present invention to provide a golf club having a head constructed by joining a plurality of metallic shells, wherein said head is protected from the excessive welding beads entering the inside and excessive heat being applied thereto.

[0011] To attain the above objects, there is provided, in accordance with a first aspect of the invention, a golf club, which comprises: a head formed by joining a plurality of separate shells one another, said separate shells including a first separate shell and a second separate shell; a shaft connected to said head, and a reinforcing means provided for reinforcing joint strength between said first separate shell and second separate shell, said reinforcing means being provided in a peripheral portion of at least said first separate shell.

[0012] With the structure thus made, the reinforcing means can improve the joint strength between the first and second separate shells to be joined. Thus, thermal deformation at the time of welding can be prevented.

[0013] According to a second aspect of the invention, there is provided a golf club according to the first aspect, wherein the peripheral portion of said first separate shell is thickened partially or entirely.

[0014] According to a third aspect of the invention, there is provided a golf club according to claim 1, wherein said reinforcing means is a separate reinforcing member which is partially or entirely provided on an inner surface of said peripheral portion of said first separate shell, so that it is thickened.

[0015] With the structures, welding portions in the shells to be joined are reinforced and thickened, thereby enabling the shells to withstand the heat in welding, and thus they are prevented from being thermally deformed by the heat. Further, said head is protected from the excessive welding beads entering the inside and excessive heat being applied thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other objects, features and advantages of the invention will be 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, of which:

[0017] FIG. 1 is an exploded perspective view showing a golf club according to a first embodiment of the invention.

[0018] FIG. 2a is a section of a golf club according to the first embodiment of the invention, while FIG. 2b is an enlarged section thereof.

[0019] FIG. 3 is a bottom view of a crown shell of a golf club according to the first embodiment of the invention.

[0020] FIG. 4 is an exploded perspective view showing a golf club according to a second embodiment of the invention.

[0021] FIG. 5 is a bottom view of a crown shell of a golf club according to the second embodiment of the invention.

[0022] FIG. 6a is a section of a golf club according to a third embodiment of the invention, while FIG. 6b is an enlarged section thereof.

[0023] FIG. 7 is an exploded perspective view showing a golf club according to the third embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0024] Hereinafter will be described an embodiment of the invention with reference to the attached drawings.

[0025] In FIGS. 1 to 3 showing a first embodiment of the invention, a metallic wood golf club commonly known as “metal wood club”, comprises a head 1 having a hosel 2 serving as a shaft attachment portion and a shaft 3 connected to the hosel 2. The head 1 is integrally formed by joining a plurality of metallic shells together. In the present embodiment, such metallic shells consist of: a face shell 4 on a front; a sole and side-peripheral shell 7 forming a sole 5 and a peripheral side portion 6; and a crown shell 8, which are made of beta type titanium alloy, respectively, and joined together by welding the respective peripheral edges one another. In the meantime, the head 1 has a hollow portion 9 with a shaft attachment pipe 10 disposed therein through the hosel 2, while a lower portion of the shaft 3 is inserted into said pipe 10. The thickness of the crown shell 8 is smaller than that of the sole and peripheral side shell 7, while the thickness of the sole and peripheral side shell 7 is smaller than that of the face shell 4.

[0026] The crown shell 8 has a front edge 8A which is formed with a plurality of projections 11, while the face shell 4 has an upper edge 4A so that said projections 11 may be anchored by resting on the upper edge 4A. Each projection 11 has a projection length A of about 2 to 3 mm, which is at most equal to a thickness B of the upper edge 4A of the face shell 4, or otherwise, slightly shorter than the thickness B. While each projection 11 has a width C of about 2 mm for example, which is nearly as wide as the said projection length A. In the embodiment, there are four projections 11 laterally spaced from each other.

[0027] Further, the front edge 8A of the crown shell 8 has reinforcing members 12 and 13 integrally fixed thereto along the inside of the front edge 8A. These reinforcing members 12 and 13 are provided at right and left sides of the front edge 8A, along the front edge 8A only, each being formed into a thin plate, having a thickness D of about 1 mm for example, approximately equal to a thickness E of the said front edge 8A, while a width W of about 5 mm so that each extends along the front edge 8A. In the embodiment, these reinforcing members 12 and 13 are integrally provided at both sides of the front edge 8A, by spot welding or the like. These reinforcing members 12 and 13 have respective front edges 12A and 13A, which project out from the end of the front edge 8A by a projection length F that is about 1 mm, for example, less than the aforesaid projection length A.

[0028] Next, a manufacture method of a golf club according to the invention will be described. The head 1 is integrally constructed by welding the respective edges of the face shell 4, the sole and peripheral side shell 7 and the crown shell 8 one another. While the welding is performed by TIG welding, the sole and peripheral side shell 7 and the crown shell 8 have such small thickness E as thin as about 1 mm or less, as above-mentioned, and thus a value of an electric current for the welding should desirably be set at 40 to 50 A that is lower than 80 to 90 A for the welding of the face shell 4 having the larger thickness B of 2 to 3 mm or above.

[0029] When welding the upper edge 4A of the face shell 4 to the front edge 8A of the crown shell 8, the distal ends of the reinforcing members 12 and 13 are abutted to the rear face of the face shell 4 while the projections 11 are allowed to rest on the upper edge 4A of the face shell 4, thereby locking the former shell relative to the latter shell. By arranging the face shell 4 and the crown shell 8 this way, a clearance 14 of about 1 mm, for example, is formed between the rear face of the face shell 4 and the front edge 8A of the crown shell 8 in these reinforcing members 12 and 13. Then, welding is performed in such a manner that beads 15 are placed between the upper edge 4A of the face shell 4 and the front edge 8A of the crown shell 8. At this moment, even though the front edge 8A of the crown shell 8 is subjected to the welding heat so that it is exposed to the risk of thermal deformation, yet the front edge 8A is reinforced by the reinforcing members 12 and 13, so that it can withstand such thermal deformation and prevent the deformation. Further, as welding is performed with the projections 11 being anchored in such a manner that rests on the upper edge 4A of the face shell 4, the front edge 8A can be prevented from sinking into the inside of the head 1 by the thermal deformation, whereby the upper edge 4A of the face shell 4 can be welded to the front edge 8A of the crown shell 8 as originally designed. Additionally, as the front edges 12A, 13A of the reinforcing members 12, 13 protruding from the front edge 8A of the crown shell 8 are abutted to the rear surface of the face shell 4 to thereby form the narrow clearance 14 between the laterally paired reinforcing members 12 and 13, the reduced amount of the sinking beads 15 as well as the better formation of the beads 15 can be achieved.

[0030] As is apparent from the foregoing, according to the foregoing embodiment of the invention, there is provided a golf club comprising the head 1 and the shaft 3 connected thereto, said head 1 consisting of the face shell 4; the sole and side-peripheral shell 7 forming the sole 5 and the peripheral side portion 6; and the crown shell 8, wherein the reinforcing members 12 and 13 are provided partly along the front edge 8A of the crown shell 8 so as to thicken the front edge 8A side of the crown shell 8 by adding the thickness D of the reinforcing members 12 and 13 to its thickness E, and then welding is performed, whereby thermal deformation at the time of welding can be prevented.

[0031] Whereas, in order to enlarge a sweet area, the center of gravity (hereinafter called C.G., not shown in the drawings) of the head 1 must be lowered and the depth of the C.G., defined as a distance between the C.G. of the head and the face shell 4, must be prolonged, and thus the crown shell 8 must be formed thin. According to the embodiment of the invention, however, only the front edge 8A of the crown shell 8 is formed thick, so that the thermal deformation at the time of welding can be prevented, even though the crown shell 8 is formed thin as a whole.

[0032] Further, the front edge 8A of the crown shell 8 is provided on a part of its inner surface with the separate reinforcing members 12, 13 so that the front edge 4A of the face shell 4 and the front edge 8A of the crown shell 8 can be welded to each other with the crown shell 8 being comparatively thickened at the front edge 8A side, whereby the front edge 8A of the crown shell 8 can have an increased thickness by adding the thickness D of the reinforcing members 12, 13 to its thickness E, thereby preventing the thermal deformation at the time of welding. Specifically, as the separate reinforcing members 12, 13 are fixed to the inner surface of the front edge 8A of the crown shell 8, scrap pieces produced when forming the respective shells 4, 7 and 8 can be used therefor, while if these reinforcing members 12 and 13 are formed thin in advance, to the preset small thickness D, the front edge 8A of the crown shell 8 can be formed to the preset thickness of “E+D”. Furthermore, as the reinforcing members 12 and 13 are separate from the crown shell 8, they can be easily arranged in any position on the crown shell 8 you like, while as the reinforcing members 12 and 13 are only arranged along the front edge 8A of the crown shell 8, they can be reduced to a minimized size to be lightened, thus minimizing the influence on the weight distribution of the head 1.

[0033] Additionally, the front edges 12A and 13A of the said reinforcing members 12 and 13 are allowed to protrude from the front edge 8A of the crown shell 8 with the front edge 8A side being thickened (E+D), and that the upper edge 4A of the face shell 4 and the front edge 8A of the crown shell 8 are joined to each other by welding, with the distal ends of the front edges 12A and 13A being abutted to the rear surface of the face shell 4, whereby there can be formed the narrow clearance 14 of a preset small dimension, between the rear surface of the face shell 4 and the front edge 8A of the crown shell 8, thus enabling better beads 15 to be formed.

[0034] In addition to the foregoing, as the welding of the upper edge 4A of the face shell 4 to the front edge 8A of the crown shell 8 is performed with the plural projections 11 provided on the front edge 8A of the crown shell 8 being anchored by the upper edge 4A of the face shell 4, the front edge 8A can be prevented from sinking at the time of welding, so that it is possible to weld the upper edge 4A to the front edge 8A as originally designed.

[0035] In FIGS. 4 and 5 showing a second embodiment of the invention, and in FIGS. 6 and 7 showing a third embodiment of the invention, the same portions as those described in the foregoing embodiment will be designated by the same reference numerals, and their repeated detailed descriptions will be omitted.

[0036] In the second embodiment, a reinforcing member 21 is integrally fixed to the inside of the front edge 8A of the crown shell 8 along the edge thereof. This reinforcing member 21 is disposed along an entirety of the front edge 8A, i.e., continuously from one side of the front edge 8A to the other side thereof, having a thickness of about 1 mm, for example, which is nearly as thin as the front edge 8A, and a width of about 5 mm. In the present embodiment, the reinforcing member 21 is integrally provided by spot welding at both sides of the front edge 8A, having a front edge 21A protruding from the front edge 8A. The projection length of the reinforcing member 21 is about 1 mm, for example, which is smaller than that of the projection 11.

[0037] Accordingly, when welding the upper edge 4A of the face shell 4 to the front edge 8A of the crown shell 8, the distal end of the reinforcing member 21 is abutted to the rear face of the face shell 4 while the projections 11 are allowed to rest on the upper edge 4A of the face shell 4, thereby anchoring the former to the latter. After that, beads 15 are placed between the upper edge 4A of the face shell 4 and the front edge 8A of the crown shell 8, to thereby perform the welding. As discussed above, even though the front edge 8A of the crown shell 8 is subjected to the welding heat so that it is exposed to the risk of thermal deformation, yet the front edge 8A is reinforced by the reinforcing member 21, so that it can withstand such thermal deformation and prevent the deformation. Further, as welding is performed with the projections 11 resting on the upper edge 4A of the face shell 4, the front edge 8A can be prevented from sinking into the inside of the head 1, when welding the upper edge 4A of the face shell 4 to the front edge 8A of the crown shell 8.

[0038] As is apparent from the foregoing, the second embodiment also is advantageous in that thermal deformation at the time of welding can be prevented like the first embodiment, and specifically advantageous in that as the reinforcing member 21 is provided along the entire length of the front edge 8A, it can be reinforced in an entire region of the front edge 8A.

[0039] In the third embodiment, cladding 31 is integrally provided in advance on the inside face of the front edge 8A of the crown shell 8, said cladding 31 being provided along the edge 8A only. The cladding 31 is provided by putting weld bead, along a part or entire length of the front edge 8A, having a thickness of about 1 mm, for example, nearly as thin as the front edge 8A, and a width of about 5 mm.

[0040] Accordingly, when welding the upper edge 4A of the face shell 4 to the front edge 8A of the crown shell 8, the upper edge 4A of the face 4 is abutted to the front edge 8A of the crown shell 8, and then, welding is carried out with the beads 15 being placed between the upper edge 4A and the front edge 8A. Thus, the front edge 8A can be reinforced by the cladding 31 when the front edge 8A side is exposed to the risk of thermal deformation by the welding heat.

[0041] Specifically, in a golf club comprising the head 1 having the shaft 3 connected thereto, said head 1 being integrally formed by joining the face shell 4; the sole and side-peripheral shell 7; and the crown shell 8, the front edge 8A of the crown shell 8 is partly or entirely provided with the cladding 31, so that the front edge 8A side of the crown shell 8 is formed thicker by adding the thickness of the cladding 31 to the thickness of the front edge 8A, whereby the thermal deformation can be prevented like in the first embodiment.

[0042] Also, as the cladding 31 is disposed along only the front edge 8A of the crown shell B, the cladding 31 can be reduced to a minimum in volume, and lightened, without uselessly disposing it where it actually is not necessary, thus minimizing the influence on the weight distribution of the head 1.

[0043] Still also, as the cladding 31 by welding is provided so as to thicken the front edge 8A side of the crown shell 8, it suffices to add the cladding step to the welding process as a preliminary treatment prior to welding the face shell 4 to the crown shell 8, said cladding step being simply providing the cladding 31 in a desired position along the front edge 8A of the crown shell 8.

[0044] Incidentally, the present invention should not be limited to the foregoing embodiments, but may be modified within the scope of the invention. For example, the present invention may apply to the welding between other shells than the face shell and the crown shell.

Claims

1. A golf club comprising:

a head formed by joining a plurality of separate shells one another, said separate shells including a first separate shell and a second separate shell;

a shaft connected to said head; and

a reinforcing means provided for reinforcing joint strength between said first separate shell and second separate shell, said reinforcing means being provided in a peripheral portion of at least said first separate shell.

2. A golf club according to claim 1, wherein said peripheral portion of said first separate shell is thickened partially or entirely.

3. A golf club according to claim 1, wherein said reinforcing means is a separate reinforcing member which is partially or entirely provided on an inner surface of said peripheral portion of said first separate shell, so that it is thickened.

4. A golf club according to claim 3, wherein said seperate reinforcing member protrudes from an end of said first separate shell.

5. A golf club according to claim 1, wherein a plurality of projections are provided on an end of at least said first separate shell so that said projections are anchored by an end of said second separate shell.

6. A golf club according to claim 1, wherein cladding is partially or entirely provided on an inner surface of said first separate shell.

7. A golf club according to claim 1, wherein said head is of a wood type.

8. A golf club according to claim 5, wherein said projections protrude by a length which is less than or at most equal to a thickness of said second separate shell.

9. A golf club according to claim 7, wherein a clearance is formed between an upper edge of a face shell and a front edge of a crown shell, while a weld bead is provided in the clearance.