The present invention relates to a golf club head that may improve hitting sound without deteriorating appearance.
A golf club head provided a hollow portion therein is known. Since the golf club head of this type is designed within a range of a limited mass, there is a tendency that a thin-wall sole portion would be designed due to increase in head volume. In order to obtain a thin-wall sole portion, a press forming product made of a thin rolled steel strip, for example, may be employed as a sole member. This aspect is advantageous in terms of productivity and cost. On the other hand, there is a problem that a golf club head having a thin-wall sole portion generates low hitting sound that many golfers do not prefer.
In order to improve the hitting sound of the golf club head, it has been proposed to provide a rib on the inner surface, which faces the hollow portion, of the sole portion (See, Patent Document 1).
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2010-115334
The rib may be fixed by welding to the inner surface of the sole portion. Heat of the rib at the time of welding affects the metal structure of the sole portion. When the thickness of the sole portion is thin, for example, the thermal energy applied from inside of the sole portion at the time of welding may change the metal structure of the outer surface of the sole portion. In this case, a welding mark such as burnt with a color change may occur on the outer surface of the sole portion. Thus there is a problem that such a welding mark makes the appearance of the head worse.
In order to hide the welding mark on the outer surface of the sole portion, there is necessity that the welding mark is covered with painting. Unfortunately, by painting, the flexibility of the sole design of the club head may be limited and the productivity may be deteriorated.
The present invention has been worked in view of the problem described above, it is an object of the present invention to provide a golf club head having an improved hitting sound without deteriorating appearance. Another object of the present invention is the provision of a golf club head that is not required limited design, in particular that is capable of having a finish treatment without painting, regarding finish treatment of a sole portion
The present invention is a golf club head provided a hollow portion therein, including a sole portion forming a bottom surface of the head, the sole portion including a thin-wall portion and a thick-wall portion having a thickness larger than that of the thin-wall portion, and a rib fixed by welding on an inner surface of the thick-wall portion.
In another aspect of the golf club head in accordance with the present invention, the thick-wall portion may include a first thick-wall portion extending in a toe-heel direction, and the rib may extend in the toe-heel direction on the first thick-wall portion.
In another aspect of the golf club head in accordance with the present invention, the thin-wall portion may include a front thin-wall portion arranged forward of the first thick-wall portion and a rear thin-wall portion arranged backward of the first thick-wall portion.
In another aspect of the golf club head in accordance with the present invention, the thick-wall portion may include a second thick-wall portion arranged forward of the front thin-wall portion, and a third thick-wall portion arranged backward of the rear thin-wall portion.
In another aspect of the golf club head in accordance with the present invention, the rib may be intermittently welded on the inner surface of the thick-wall portion in a longitudinal direction of the rib.
In another aspect of the golf club head in accordance with the present invention, the rib may be intermittently welded on the inner surface of the thick-wall portion at positions of its longitudinal both ends and at least one place between the both ends.
In another aspect of the golf club head in accordance with the present invention, the rib may have a height of from 2 to 6 mm and a width of from 0.5 to 1.5 mm.
In another aspect of the golf club head in accordance with the present invention, the difference between thicknesses of the thick-wall portion and the thin-wall portion may be not less than 0.3 mm.
In another aspect of the golf club head in accordance with the present invention, the thick-wall portion may have a thickness of from 0.8 to 1.6 mm.
In another aspect of the golf club head in accordance with the present invention, the sole portion may have a region including a welded position of the rib, and an outer surface of the region may be finished without painting.
In another aspect of the golf club head in accordance with the present invention, the finish treatment may include mirror finish.
The sole portion of the golf club head in accordance with the present invention includes the thin-wall portion and the thick-wall portion having a thickness larger than that of the thin-wall portion. The thin-wall portion is useful for provision of a larger head volume by providing the sole portion with small mass. The rib is fixed by welding to the inner surface of the thick-wall portion. The rib may improve the hitting sound by increasing the rigidity of the sole portion so as to reduce its vibration.
Since the thermal capacity of the thick-wall portion of the sole portion is greater than that of the thin-wall portion, the effects of heat hardly lead to the outer surface of the sole portion when the rib is welded to the inner surface of the thick-wall portion of the sole portion. Accordingly, in the golf club head in accordance with the present invention, a welding mark does not appear on the outer surface of the sole portion at all, or appears in a small size that is unrecognized by naked eyes. Therefore the golf club head in accordance with the present invention may prevent the deterioration of appearance of the sole portion.
The sole portion of the golf club head in accordance with the present invention maintains an excellent appearance without painting. Accordingly, the finish treatment without painting such as mirror finish may be employed. This makes it possible to provide a degree of freedom for designing the sole portion of the golf club head and improve productivity of the golf club head.
An embodiment of the present invention will be explained below with reference to the accompanying drawings.
Referring to
As shown in
The head 1 in accordance with the present embodiment is a wood-type. The wood-type head typically includes both kinds of driver head (#1) and fairway wood head. Furthermore, the concept of the wood-type head further includes a kind of utility-type head having the different club name and numbers from those. The wood-type golf club head generally has a loft angle in a range of from 8 to 30 degrees.
The head 1 has a volume in a range of not less than 90 cm3, more preferably not less than 100 cm3. On the other hand, the head 1 has a volume in a range of not more than 470 cm3, more preferably not more than 460 cm3; in view of the golf rules.
The head 1 has a mass in a range of not less than 170 g, more preferably not less than 180 g, but preferably not more than 260 g, more preferably not more than 250 g for better golf swings.
As shown in
As used herein, various directions for the head 1 are defined. The front side of the head 1 means the side of the face 2 relatively, and the opposite side is the rear side of the head 1. Furthermore, the toe-heel direction of the head 1 refers to a direction parallel to the centerline CL of the shaft insertion hole 7a on the bottom view of the head 1 under the standard condition as shown in
The major part of the head 1, for example, is made of metallic material. Namely, the face portion 3, the crown portion 4, the sole portion 5 and the hosel portion 7 are made of metallic material. For example, the metallic material for forming the head 1 may be employed stainless steel, a maraging alloy, a titanium alloy or the like.
As shown in
The face member 1A includes the face 2. The face member 1A, for example, is formed of a plate shape. For the face member 1A, a cup-like shape including a flange (not shown) extending rearwardly from the periphery of the face 2 may preferably be used.
The head main body member 1B includes the crown portion 4 and the side portion 6. The face member 1A is fixed to the front side of the head main body member 1B. The head main body member 1B has a recess for attaching the neck member 1D on its heel side.
The sole member 1C includes the sole portion 5, and is formed of a plate shape. In this embodiment, the sole member 1C is a press formed product in which rolled steel or the like is plastically deformed by press forming. For example, the sole member 1C is fixed to lower edges of the respective face member 1A and the head main body member 1B by welding.
The neck member 1D includes the hosel portion 7, and is formed using NC machining. The neck member 1D is fixed to the recess of the head main body member 1B.
In order to optimize the location of the center of gravity of the head and the repulsion performance, the respective members 1A to 1D may be made of metallic materials having different specific gravities. In this embodiment, each of the members 1A to 1D is made of a titanium alloy. Preferably, the whole head 1 may be made of a metallic material. Alternatively, a fiber reinforced resin may be used as a part of the head 1.
In order to resist impact of hitting a golf ball, the face portion 3 is required to have sufficient strength. As shown in
In order to resist impact of hitting a golf ball, the crown portion 4 is also required to have sufficient strength. On the other hand, the thickness of the crown portion 4 is large, the head 1 tends to have high center of gravity. In view of the above, the thickness t2 of the crown portion 4 is preferably in a range of approximately 0.5 to 0.9 mm.
The side portion 6 preferably has a thickness t3 in a range of from 0.7 to 1.2 mm in order to maintain the lightweight of the head and high moment of inertia around the vertical axis passing through the center of gravity of the head in well balance.
The sole portion 5 includes a thin-wall portion 8 and a thick-wall portion 9 having a thickness larger than that of the thin-wall portion 8. The reduced mass from the sole portion 5 by providing the thin-wall portion 8 may be redistributed to the thick-wall portion 9. Thus the weight may be flexibly and arbitrarily distributed into the sole portion 5 based on locations of the thin-wall portion 8 and the thick-wall portion 9. Accordingly, the location of the center of gravity of the head and the amount of the moment of inertia may be designed.
Furthermore, the thick-wall portion 9 has bending rigidity larger than that of the thin-wall portion 8. Thus rigidity of the sole portion 5 may be changed due to the location of the thick-wall portion 9.
Thus, the center of gravity of the head, moment of inertia and rigidity distribution of the sole portion 5 may be flexibly designed by modifying the locations of the thin-wall portion 8 and the thick-wall portion 9. These specific examples will be described later.
In the present invention, as shown in
Furthermore, since the thermal capacity of the thick-wall portion 9 of the sole portion 5 is greater than that of the thin-wall portion 8, the effects of heat hardly lead to the outer surface 5o of the sole portion 5 when the rib 10 is welded to the inner surface 5i of the sole portion 5. Accordingly, in the golf club head 1 in accordance with the present invention, a welding mark does not appear at all on the outer surface 5o of the sole portion 5, or appears in a very small size that is unrecognized by naked eyes. Thus the outer surface 5o of the sole portion 5 may exhibit an excellent appearance. The outer surface 5o of the sole portion 5 may be finished as mirror treatment by buffing the sole member 1C without painting, for example. The head 1 in accordance with the present invention may offer a high degree of freedom for designing the outer surface 5o of the sole portion 5 while eliminating requirement of painting and improve productivity.
The cross sectional shape of the rib 10, which is not particularly limited, may include a semicircular shape, a triangular shape and the like. As shown in
The whole length of the rib 10 measured along the rib, which is not particularly limited, is preferably in a range of from 3% to 75% of the maximum toe-heel length L1 of the head 1, as shown in
The number of rib 10 provided on the sole portion 5, which is not particularly limited, is preferably in a range of from approximately 1 to 3.
As shown in
As shown in
The thin-wall portion 8, for example, includes a front thin-wall portion 8A arranged forward of the first thick-wall portion 9A and a rear thin-wall portion 8B arranged backward of the first thick-wall portion 9A. In the preferred embodiment, the thick-wall portion 9 further includes a second thick-wall portion 9B arranged forward of the front thin-wall portion 8A and a third thick-wall portion 9C arranged backward of the rear thin-wall portion 8B. Furthermore, the whole area of the heel side of the sole portion 5 in accordance with the present embodiment is formed of a fourth thick-wall portion 9D. Such a sole portion 5 may have high moment of inertia around a vertical axis because sufficient weight is distributed in the periphery of the sole portion 5. Furthermore, since the peripheral portion of the sole member 1C has a large thickness, the sole portion 5 may have high durability so as to prevent heat injury thereon when welding to the other member.
As shown in
In the embodiment as described above, the thermal energy applied to the sole portion 5 when welding is suppressed to be very low. Thus the thermal effect on the outer surface 5o of the sole portion 5 is also suppressed to be minimum, thereby effectively preventing the generation of the welding mark thereon. The specific process of welding is not particularly limited, but arc welding with small output, particularly TIG welding and the like is preferable.
As shown in
In order to prevent increase of mass while maintaining sufficient thermal capacity, the thickness t4 of the thick-wall portion 9 is preferably not less than 0.8 mm, more preferably not less than 0.9 mm, still further preferably not less than 1.0 mm, but preferably not more than 1.6 mm, more preferably not more than 1.4 mm, still further preferably not more than 1.2 mm.
In order to ensure durability of the sole portion while maintaining mass margin, the thickness t5 of the thin-wall portion 8 is preferably not less than 0.5 mm, more preferably not less than 0.6 mm, still further preferably not less than 0.7 mm, but preferably not more than 1.0 mm, more preferably not more than 0.9 mm, still further preferably not more than 0.8 mm.
The difference t4−t5 between the thickness t4 of the thick-wall portion 9 and the thickness t5 of the thin-wall portion 8 is preferably not less than 0.2 mm, more preferably not less than 0.3 mm. On the other hand, the thickness difference t4−t5 is excessively large, stress tends to concentrate the boundary between them and to lower the durability of the sole portion 5. Thus the thickness difference t4−t5 is preferably set not more than 0.8 mm.
The sole member 1C which includes the thick-wall portion 9 and the thin-wall portion 8, for example, is formed from a first molding product having a constant thickness. In this embodiment, the thin-wall portion 8 is shaped by dissolving a part of the first molding product through an etching process. The thick-wall portion 9 is formed of the non-etching part having the original thickness of the first molding product by being masked during the etching process. With this, the sole member 1C is obtained in high productivity.
In the head 1 in accordance with the present embodiment, the welding mark does not substantially appear on the outer surface 5o of the sole portion 5. Thus the sole portion 5 has a region including a welded position of the rib 10, wherein the outer surface of the region is finished without painting.
The finish treatment includes mirror finish, for example. The mirror finish is to polish a target area to obtain a smooth surface as a mirror by a buff or barrel type polishing means. For the degree of mirror finish, it is preferable that the outer surface 5o of the sole portion 5 is polished up to be able to reflect a skin color of a person.
Furthermore, in another aspect of the finish treatment, a hairline finish, a satin finish, or a satin-mirror finish may be employed. The hairline finish is a finish that has an outer surface with very narrow lines on it each of which appears as a hair, and a matte surface condition as compared to the mirror finish. Satin finish may provide a luster surface with matte appearance which is milder than the mirror finish by processing with abrasive paper coarser than buff, rubbing with a wire brush or using a combination of chemicals. Satin-mirror finish is an approximately intermediate finish between satin and mirror finishes with respect to a mirror condition. With respect to the finish treatment without painting to the outer surface 5o of the sole portion 5, it is not particularly limited to these.
While the particularly preferable embodiments in accordance with the present invention have been described in detail, the present invention is not limited to the specific embodiments, but can be modified and carried out in various aspects.
Wood type golf club heads having a basic structure shown in
Gas: Argon gas
Gas current: 5 to 10 (l/min.)
Welding current: 80 plus/minus 10 (A)
Welding speed: zero (spot welding)
Number of welding portions: five (one means a set of welded bead portions on both sides of rib in its width direction)
Maximum outer diameter of welding portions: 2 to 6 mm
Existence of Welding Mark
The existence of a welding mark on the outer surface of the sole portion of the respective heads was checked by naked eyes.
Natural Frequency
As for the hitting sound, a primary natural frequency of the head was measured. The primary natural frequency was measured in the head alone. The measurement method is as follow:
From the test results, it was confirmed that the example golf club heads had improved the hitting sound without deteriorating appearance.
Number | Date | Country | Kind |
---|---|---|---|
2012-264604 | Dec 2012 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2013/081481 | 11/22/2013 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2014/087851 | 6/12/2014 | WO | A |
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8647217 | Nishio | Feb 2014 | B2 |
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20100273574 | Yamamoto | Oct 2010 | A1 |
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20120142450 | Wada | Jun 2012 | A1 |
Number | Date | Country |
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11-114107 | Apr 1999 | JP |
2006-110008 | Apr 2006 | JP |
2007-7327 | Jan 2007 | JP |
2010-115334 | May 2010 | JP |
2010-252897 | Nov 2010 | JP |
2012-396 | Jan 2012 | JP |
Entry |
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International Search Report issued in PCT/JP2013/081481, dated Feb. 25, 2014. |
Number | Date | Country | |
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20150273290 A1 | Oct 2015 | US |