US20020077193A1 - Golf club and golf club head - Google Patents

Abstract

A golf club whose balance adjustment is easily performed without reducing the strength of a shaft. A golf club basically comprises a head body1with one side; a hosel hole4with an opening on the one side; and a shaft2fitted thereinto. The hosel hole4comprises a first hole5extending from the opening; and a second hole6extending from a bottom of the first hole5.The first hole5allows the shaft2to be fitted thereinto, while the second hole6allows one of weight-adjustment balance weights7to be provided therein.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0001]
• The present invention relates to a golf club and a golf club head.[0002]
• 2. Description of the Related Art[0003]
• Due to the increased number of golfers, golf clubs have been manufactured by mass production. Golf clubs have respective centers of gravity (i.e., C. G.) determined at a stage of designing. If the weight of a shaft and a grip is determined, then the position of the center of gravity is determined by the weight of a golf club head. Therefore golf clubs have respective standard weight determined, corresponding to the respective positions of the C.G. In mass production, however, it has actually been impossible to manufacture golf club heads so that all of them may have the weight in accordance with the respective standards when they are finished. Accordingly, tolerance has been given so far to the standard weight so that golf club heads could be manufactured within the weight tolerance in a range of 4 g. For a head heavier than the standard weight, the balance adjustment thereof is generally difficult. For this reason, a head body has preliminarily been manufactured so that it may be lighter than the standard weight, while the short weight has been compensated for by putting a balance weight within a shaft when they are assembled.[0004]
• FIG. 4 shows one example of conventional methods for adjusting the weight balance, in which a[0005]shaft hole12 is formed in agolf club head11, and after ashaft14 is fixed in theshaft hole12 with adhesive13,metal powder15 such as that of tungsten of a high specific gravity is measured to exactly weigh the deficit in weight, and then put into acavity14A of theshaft14 from a grip side, said metal powder being fixed at the lower end portion of theshaft14 by a plug such as acork plug16. Herereference numeral17 in FIG. 4 denotes a ferrule.
• FIG. 5 shows another example of conventional methods, wherein as the[0006]shaft14 is bonded with the adhesive13, a somewhat larger quantity of theadhesive13 is put into theshaft hole12. As theshaft14 is made of a hollow pipe and the center portion thereof is hollow, an excessive amount of theadhesive13 is allowed to get into thecavity14A, so that a slender andcylindrical lead body18 or the like can be put into theshaft14 from the grip side prior to the solidifying of theadhesive13 to thereby fix thelead body18 while solidifying the adhesive13.
• However, there have been the following problems in these conventional golf clubs:[0007]
• According to the conventional golf clubs of which the weight balance is adjusted by the foregoing former method, using the[0008]metal powder15 as the balance-adjustment material, there has been such a problem that the position of the C.G. of the head deviates from what was originally designed because themetal powder15 undesirably extends up to the grip portion in thecavity14A due to the high void content of the metal powder as well as the high volume-to-weight ratio thereof when the inside diameter of theshaft14 remains unchanged.
• Moreover if the cork plug comes off, such problem arises that clattering occurs due to the[0009]metal powder15 moving freely in thecavity14A of theshaft14.
• According to the conventional golf clubs of which the weight balance is adjusted by the foregoing latter method, the method is advantageously simple as one has only to insert the[0010]lead body18, yet it has a drawback that unless rapid work is done skillfully, thelead body18 cannot be fixed as the solidification of the adhesive13 proceeds. Further, to fix thelead body18 firmly, thelead body18 must be embedded into theadhesive13 to some depth, which in turn means that theadhesive13 extends beyond a line A at the upper end of theshaft hole12 in thecavity14A, In that case, however, the investigation by the present inventor has revealed that the mechanical strength of theshaft14 is lowered by about 20-30% as a result. Although it is not necessarily clear what has caused such lowered strength, it is presumably due to the fact that if theadhesive13 is solidified in a portion beyond the upper end A of theshaft hole12 within thecavity portion14, the elasticity of theshaft14 is lowered at that portion, and thus the impact at the time of hitting or the like is transmitted directly to theshaft14 without being reduced.
SUMMARY OF THE INVENTION
• To eliminate the aforementioned problems, it is, therefore, an object of the present invention to provide a golf club in which the adjustment of the weight balance is easily performed without reducing the strength of a shaft.[0011]
• It is another object of the present invention to provide a golf club head in which the adjustment of the weight balance is easily performed without reducing the strength of a shaft.[0012]
• To attain the above objects, there is proposed a golf club according to a first aspect of the present invention, comprising: a head body with one side; a hosel hole with an opening on said one side of the head body; and a shaft fitted thereinto, wherein said hosel hole comprises: a first hole extending from said opening; and a second hole extending from a bottom of said first hole, said first hole having said shaft fitted thereinto, while said second hole having one of weight-adjustment balance weights provided therein.[0013]
• Accordingly, the adjustment of the weight balance in a golf club can be performed simply by first inserting the weight-adjustment balance weight into the second hole and then fitting the shaft into first hole. Further, there can be obtained a good position of the C.G in the golf club as the weight-adjustment balance weight is disposed in the lowermost bottom portion of the hosel hole. Furthermore, no clattering occurs because no powder is used unlike conventional golf clubs. Additionally, there is no reduction in strength of a shaft because the adhesive does not need to be present in a portion beyond the upper end of the shaft hole in the hollow portion of the shaft.[0014]
• There is also proposed a golf club head according to another aspect of the present invention, comprising: a head body with a hosel hole on one side, wherein said hosel hole comprises: a first hole extending from an opening of said hosel hole; and a second hole extending from a bottom of said first hole, said first hole having a shaft fitted thereinto, while said second hole having one of weight-adjustment balance weights provided therein, said weight-adjustment balance weights being prepared in order that the difference in weight relative to standard weight may be within 0.5 g. Accordingly it is possible to mass-product golf club heads whose weight is closer to the standard weight than those conventionally produced, and to easily achieve the weight balance set in advance to respective golf clubs.[0015]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is an exploded perspective view showing a golf club in accordance with an embodiment of the present invention.[0016]
• FIG. 2 is a cross-sectional view illustrating a structure for attachment of a shaft in said embodiment.[0017]
• FIG. 3 is an exploded perspective view showing a balance weight for adjusting weight.[0018]
• FIG. 4 is a cross-sectional view showing a conventional structure for attachment of a shaft.[0019]
• FIG. 5 also is a cross-sectional view showing another conventional structure for attachment of a shaft.[0020]
DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Hereunder is a description of an embodiment of a golf club and a golf club head in accordance with the present invention with reference to FIG. 1 through FIG. 3.[0021]
• As shown in FIG. 1, a golf club of the present embodiment is an iron type golf club, comprising a[0022]metal head body1 that constructs a golf club head and ashaft2 that is a hollow pipe, saidshaft2 being fitted in ahosel hole4 which is formed in ahosel portion3 provided on one side of thehead body1.
• A structure for attaching the[0023]shaft2 is shown in FIG. 2. In the embodiment, a distal end of theshaft2 is 9.4 mm in diameter, while saidhosel hole4 including afirst hole5 of a larger diameter and asecond hole6 of a smaller diameter formed at the lower portion of thefirst hole5. Thefirst hole5 is formed to have a 9.5 mm φ diameter that is 0.1 mm larger than that of the distal end of theshaft2 and to have a 29 mm depth. Thesecond hole6 is formed to have a 5 mm diameter that is smaller than that of thefirst hole5 and to have a 5 mm depth.
• The weight-[0024]adjustment balance weight7 is housed in thesecond hole6. Said weight-adjustment balance weight7 is made of a tungsten alloy (the specific gravity: 17 to 18 g/cm3) manufactured by sintering process, and is formed into a short and columnar shape, of which the diameter and height are just enough to fit to thesecond hole6. As shown in FIG. 3, a through-hole8 is formed through the side face of said weight-adjustment balance weight7 according to where it is necessary. By varying the size of the diameter of the through-hole8, a plurality of thebalance weights7 each being of the same external shape but different in weight by 0.5 g, such as 4 g, 3.5 g, 3 g, . . . 0.5 g can be prepared beforehand. In the meantime,reference numeral10 in FIG. 1 and FIG. 2. denotes a ferrule.
• A golf club according to the foregoing structure can be produced in the following manner. That is:[0025]
• In the first place, a[0026]head body1 is manufactured by forging or the like, and then the difference between the weight of thehead body1 and standard weight is calculated so as to determine the weight to be adjusted. Thereafter, one of thebalance weights7 whose weight is the closest to the weight thus determined is selected so that thebalance weight7 thus selected is placed in thesecond hole6 of thehosel hole4 to thereby adjust the weight of thehead body1. Thereafter theadhesive9 is applied to the distal end of theshaft2 and the inner surface of thefirst hole5 of thehosel hole4, and then theshaft2 is fitted in thefirst hole5. As a result, a golf club with a correct position of the center of gravity as well as the excellent weight balance can be assembled. In that case, advance setting is desirable in order that thehead1 may be finished to a little lighter weight than the standard weight. In the case that the difference in weight between the head body and the standardized one is smaller than 0.5 g, anybalance weight7 does not need to be placed in thesecond hole6, or otherwise, alighter balance weight7 made of a material of a low specific gravity such as plastic may be prepared beforehand to be placed in thesecond hole6.
• As aforementioned, a golf club according to the above embodiment comprises: the[0027]head body1 having one side; thehosel hole4 with an opening on said one side of thehead body1; and theshaft2 attached thereto, wherein saidhosel hole4 comprises: thefirst hole5 extending from said opening; and thesecond hole6 extending from a bottom of saidfirst hole5, saidshaft2 being fitted into saidfirst hole5, while the weight-adjustment balance weight7 being placed in saidsecond hole6.
• Accordingly, the adjustment of the weight balance in a golf club can be performed simply by first inserting the weight-[0028]adjustment balance weight7 into thesecond hole6 and then fitting theshaft2 intofirst hole5. Further, good weight balance is achieved because the position of the C.G in the golf club can be free from substantial deviations as the weight-adjustment balance weight7 is disposed in a portion of thehead body1 that is in the bottom of thehosel hole4. Furthermore, no clattering occurs because no powder is used unlike conventional golf clubs. Additionally, there is no reduction in strength of a shaft because the adhesive does not need to be present in a portion beyond the upper end of the shaft hole in the hollow portion of theshaft2.
• Moreover, according to the[0029]head body1 that constructs a golf club head of the present invention, a plurality of thebalance weights7 are prepared in order that therespective balance weights7 may vary weight in units of 5 g, so that a tolerance of 0.5 g or below relative to the standard weight is achieved, thereby making it possible to mass-product golf club heads (corresponding to a head body1) whose weight is closer to the standard weight than those conventionally produced. Specifically, as the weight-adjustment of thebalance weights7 is performed by forming the through-hole8 in thebalance weight7 in the present embodiment, it is possible to prepare various weights each being of different weight but in the same external form, whereby the dimensions of thebalance weights7 can be in accord with that of thesecond hole6 in diameter and depth so that thebalance weight7 can be fitted firmly and tightly.
• Incidentally, the present invention should not be limited to the aforementioned embodiment, but various modifications are possible within the scope of the invention. For example, although the[0030]second hole6 is formed round and thebalance weight7 is formed short and columnar in the aforementioned embodiment, thesecond hole6 may be formed square, and thebalance weight7 cubic. Further, thefirst hole5 and the distal portion of theshaft2 may be each threaded so that both can be engaged to each other to be fitted. Although thefirst hole5 is formed larger in diameter and thesecond hole6 smaller in the aforementioned embodiment, both holes may be formed to define the same diameter. In that case, theholes5 and6 may be discriminated from each other in a manner that the portion in which thebalance weight7 is fitted defines thesecond hole6, while the portion into which theshaft2 is fixedly inserted defines thefirst hole5. Moreover, although weight is adjusted in units of 0.5 g in the aforementioned embodiment, several balance weights with varying weight in units of 0.3 g for example may be prepared so that finer adjustment of weight may be possible, corresponding to the resultant smaller differences in weight. Alternatively, it goes without saying that the present invention is not limited to an iron type golf club, but may be applied to a variety of golf clubs such as a metal or wooden wood golf club that needs to be adjusted in weight.

Claims (10)

What is claimed is:

1. A golf club which comprising: a head body with one side, a hosel hole with an opening on said one side of the head body; and a shaft fitted thereinto, wherein said hosel hole comprises: a first hole extending from said opening; and a second hole extending from a bottom of said first hole, said first hole having said shaft fitted thereinto, while said second hole having one of weight-adjustment balance weights provided therein.

2. A golf club head comprising a head body with a hosel hole on one side, wherein said hosel hole comprises: a first hole extending from an opening of said hosel hole; and a second hole extending from a bottom of said first hole, said first hole having a shaft fitted thereinto, while said second hole having one of weight-adjustment balance weights provided therein, said weight-adjustment balance weights being prepared in order that the difference in weight between the golf club head and a standardized one may be within 5 g.

3. A golf club according toclaim 1, further comprising a through-hole formed through a side face of said weight-adjustment balance weight, wherein the adjustment of weight is performed by varying a size of a diameter of said through-hole.

4. A golf club head according toclaim 2, further comprising a through-hole formed through a side face of said weight-adjustment balance weight, wherein the adjustment of weight is performed in units of 5 g by varying a size of a diameter of said through-hole.

5. A golf club according toclaim 3, wherein said weight-adjustment balance weight is of a short and columnar shape.

6. A golf club head according toclaim 4, wherein said weight-adjustment balance weight is of a short and columnar shape.

7. A golf club according toclaim 5, wherein said weight-adjustment balance weight is made of tungsten alloy.

8. A golf club head according toclaim 6, wherein said weight-adjustment balance weight is made of tungsten alloy.

9. A golf club according toclaim 5, wherein said weight-adjustment balance weight is made of plastic.

10. A golf club head according toclaim 6, wherein said weight-adjustment balance weight is made of plastic.

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