This application claims a priority to Japanese Patent Application No. 2015-117059 filed on Jun. 9, 2015, which is hereby incorporated by reference in its entirety.
The present invention relates to a golf club head.
In recent years, various golf club heads provided with a weight member in a sole portion thereof have been proposed. For example, in the golf club head disclosed in JP 5678004, the sole portion has a weight member that extends out past the natural outline of the golf club head. This weight member is arranged, however, so as to not be visible to the golfer when he or she in the address position.
However, the weight member protrudes from the sole portion of the golf club head, and thus there is a concern that the weight member will catch on the ground when the golf club head is swung. Also, the weight member is attached with the object of lowering the center of gravity of the head, but to lengthen the flight distance, there is demand for a golf club head with an even lower center of gravity. The present invention was made in order to resolve these problems, and an object thereof is to provide a golf club head with which a lower center of gravity can be realized without a weight member protruding from the sole portion.
A golf club head according to the present invention includes a crown portion, a face portion, and a sole portion having at least one recessed portion. The recessed portion is configured to house a weight member such that the weight member does not protrude externally, the sole portion is provided with a raised portion that includes the recessed portion, protrudes downward and is at least partially placed on a placement surface in a reference state, and a center of the recessed portion is arranged further to a back side in a face-back direction and to a heel side in a toe-heel direction than a center of gravity of the head.
The above golf club head can be configured such that the raised portion is surrounded by a first edge portion that runs along a vicinity of a boundary between the sole portion and the face portion, a second edge portion that extends from the heel side to a vicinity of a midpoint in the toe-heel direction, along a vicinity of a boundary between the sole portion and the crown portion, and a third edge portion that joins an end portion of the second edge portion on a toe side and an end portion of the first edge portion on the toe side.
Each of the above golf club heads can be configured such that the second edge portion has a protruding portion formed by a part of a peripheral edge of the recessed portion protruding on the heel side.
Each of the above golf club heads can be configured to further include a weight member and a decoration member to be arranged in the recessed portion, and such that the decoration member is fixed in the recessed portion by the weight member.
Each of the above golf club heads can be configured such that, when the head in the reference state is seen in back view, at least 60% of an area of the raised portion is arranged further to the heel side than a line extending in the face-back direction through a furthest point on the back side of the sole portion.
With a golf club head according to an one aspect of embodiment, a lower center of gravity can be realized without the weight member protruding from the sole portion.
An embodiment of a golf club head according to the present invention will be described below with reference to the drawings.
1. Overview of Golf Club Head
As shown in
The face portion 1 has a face surface, which is the surface that hits the ball, and the crown portion 2 is adjacent to the face portion 1 and constitutes the upper surface of the head. The sole portion 3 constitutes the bottom surface of the head, and is adjacent to the face portion 1 and the side portion 4. Also, the side portion 4 is the region between the crown portion 2 and the sole portion 3, and extends from the toe side of the face portion 1 to the heel side of the face portion 1 across the back side of the head. Furthermore, the hosel portion 5 is the region provided adjacent to the heel side of the crown portion 2, and has an insertion hole 51 for insertion of the shaft (not shown) of the golf club. A central axis Z of the insertion hole 51 coincides with the axis of the shaft.
The following describes the aforementioned reference state. First, as shown in
In the present embodiment, the boundary between the crown portion 2 and the side portion 4 can be defined as follows. Specifically, if a ridge line is formed between the crown portion 2 and the side portion 4, that ridge line serves as the boundary. In contrast, if a clear ridge line is not formed, the boundary is the outline that is seen when the head is placed in the reference state and viewed from directly above the center of gravity of the head. Similarly, in the case of the boundary between the face portion 1 and the crown portion 2 and between the face portion 1 and the sole portion 3, if a ridge line is formed, that ridge line serves as the boundary. However, if a clear ridge line is not formed, the peripheral edge (boundary) of the face portion 1 is defined by positions Pe where, in each cross-section E1, E2, E3 and so on that include a straight line N connecting the center of gravity G of the head and a sweet spot SS as shown in
Also, in the present embodiment, the boundary between the sole portion 3 and the face portion 1 and between the sole portion 3 and the side portion 4 can be defined as follows. Specifically, if a ridge line is formed between the sole portion 3 and the face portion 1 and between the sole portion 3 and the side portion 4, that ridge line serves as the boundary. Also, although the golf club head according to the present embodiment has the side portion 4, in cases such as where, for example, the side portion 4 is not provided, the side portion 4 cannot be clearly distinguished and is included in the sole portion 3, or the sole portion 3 is directly connected to the crown portion 2, the ridge line between the sole portion 3 and the crown portion 2 serves as the boundary between both portions. Also, if a clear ridge line is not formed, the boundary is the outline that is seen when the head is placed in the reference state and viewed from directly above the center of gravity of the head 10. Note that, in consideration also of the case where the side portion cannot be clearly distinguished as described above, the “sole portion” according to the present invention is deemed to include the side portion.
Next, the sole portion will be described. As shown in
A circular recessed portion 31 is formed inside the raised portion 30. As described below, a decoration member 6 and a fixing member 7 for fixing this decoration member 6 in the recessed portion 31 are arranged in the recessed portion 31. Also, in order to fix the fixing member 7 in the recessed portion 31, a fixing hole 312 in which a female thread is formed is provided in the center of a bottom surface 311 of the recessed portion 31. The position of this fixing hole 312 is arranged further to the back side in the face-back direction and to the heel side in the toe-heel direction than the center of gravity of the head.
Furthermore, a part of the peripheral edge of the recessed portion 31 protrudes from the second edge portion 302 toward the heel side, and accordingly an arc-shaped protruding portion 304 that constitutes part of the peripheral edge of the recessed portion 31 is formed in the second edge portion 302.
Also, as shown in
Thus, the rear region 307 extends so as to incline from the boundary 309 toward the back side. Specifically, the rear region 307 inclines so as to be oriented upward toward the back side. At this time, the rear region 307 and the placement region 306 are preferably connected so as to intersect each other at an angle α of approximately 4° to 10°. This is because, as described below, rigidity decreases and vibrations from the face portion 1 are fully transmitted to the rear region 307 if the angle α is less than 4°, and the center of gravity of the sole portion 3 is raised if the angle α is more than 10°.
The raised portion 30 is mainly arranged on the heel portion side of the sole portion 3, and when the head 10 in the reference state is seen in back view, at least 60% of the area of the raised portion 30 can be arranged further to the heel side than a line extending in the face-back direction through the furthest point on the back side of the sole portion 3. Note that the furthermost point on the back side of the sole portion 3 is specified from the outline of the head in the reference state when seen in back view.
The volume of this golf club head is, for example, preferably 300 cm3 or more, more preferably 400 cm3 or more, and particularly preferably 420 cm3 or more. A head having such a volume serves to make the golfer feel more confident when the club is held at address, and also to increase the sweet spot area and the moment of inertia. Note that although an upper limit of the head volume is not particularly defined, in terms of practical use, it is, for example, desirably 500 cm3 or less, and desirably 470 cm3 or less when complying with R&A or USGA rules and regulations.
Also, the head can be formed from, for example, a titanium alloy (e.g., Ti-6Al-4V) having a specific gravity of approximately 4.4 to 4.5. Besides a titanium alloy, the head can be formed from one or a plurality of materials selected from among stainless steel, maraging steel, an aluminum alloy, a magnesium alloy, an amorphous alloy, and the like. Such a golf club head can be produced using various methods, and can, for example, be manufactured by casting using a known lost wax precision casting method or the like.
Note that the head according the present embodiment is configured by assembling a head body that has at least the sole portion 3 and another portion. For example, the head can be configured by constituting only the face portion 1 as a separate member and attaching the face portion 1 to the head body, or alternatively, the head can be configured by forming a head body with an opening provided in the crown portion 2 or the side portion 4 and blocking the opening with a separate member. Also, a cup face structure provided with a peripheral edge portion surrounding the face portion 1 can be employed.
2. Fixing Member
Next, the fixing member 7 will be described with reference to
As shown in
The material forming the fixing member 7 is not particularly limited, and a metal such as aluminum or stainless steel, a resin material or the like can be used, for example. Also, this fixing member 7 is used as a weight for adjustment. Specifically, a plurality of types of differently weighted fixing members 7 with substantially the same shape are prepared. The weight and the center of gravity of the head can then be changed by using one of the plurality of types of fixing members 7.
3. Decoration Member
Next, the decoration member 6 will be described with reference to
As shown in
The through hole 61 is formed in order to attach the fixing member 7, and is constituted by three cylindrical regions. Specifically, the through hole 61 is constituted by a first portion 611 into which the shaft portion 72 of the fixing member 7 is to be inserted, a second portion 612 having a larger diameter than the first portion 611 and in which the head portion 71 is to be arranged, and a third portion 613 having a larger diameter than the second portion 612 and forming a gap on the peripheral edge of the head portion 71, and the first to third portions 611 to 613 are formed in the stated order so as to be continuous from the lower side to the upper side of the through hole 61.
The first portion 611 is formed with a slightly larger diameter than the shaft portion 72 of the fixing member 7. The second portion 612 has a larger diameter than the diameter of the first portion 611, and thus a first step portion 614 is formed between the second portion 612 and the first portion 611, and the lower surface of the head portion 71 of the fixing member 7 is configured to be placed on this first step portion 614. At this time, the depth of the first step portion 614 is prescribed such that the upper surface of the head portion 71 and the upper surface of the decoration member 6 are arranged generally on the same plane. Also, the inner wall surface of the second portion 612 is formed with a taper whose diameter decreases downward, and corresponds to the taper of the outer peripheral surface 713 of the head portion 71 of the fixing member 7.
The third portion 613 is formed with a slightly larger diameter than the diameter of the second portion 612, and when the head portion 71 of the fixing member 7 is mounted in the decoration member 6, the third portion 613 forms a gap with the peripheral edge of the head portion 71 of the fixing member 7. Specifically, a gap D is formed between the outer peripheral surface 713 of the head portion 71 and the inner wall surface of the third portion 613 (see
The material forming the decoration member 6 is not particularly limited, and the decoration member 6 can also be formed with a metal such as stainless steel or aluminum, a resin material or the like, for example. Also, similarly to the fixing member 7, the decoration member 6 can be used as a weight for adjustment.
4. Attachment of Fixing Member and Decoration Member
Next, attachment of the fixing member and the decoration member will be described with reference to
First, after an adhesive is applied to the lower surface of the decoration member 6, the decoration member 6 is arranged in the recessed portion 31 of the sole portion 3. Then, the fixing member 7 is arranged in the through hole 61 of the decoration member 6, and a hex wrench is inserted into the tool hole 712 of the upper surface of the fixing member 7 and rotated. The male thread of the shaft portion 72 of the fixing member 7 is thereby screwed into the female thread of the recessed portion 31. Then, when the fixing member 7 has been completely screwed in, the upper surface of the head portion 71 and the upper surface of the decoration member 6 are substantially level with each other. Attachment of the fixing member 7 and the decoration member 6 is thus completed, as shown in
5. Features
According to the present embodiment, as described above, the following effects can be obtained.
(1) The raised portion 30 protruding downward is formed on the sole portion 3, and thus the position of the center of gravity of the head 10 can be lowered. In particular, because the recessed portion 31 to which the fixing member 7 and the decoration member 6 that function as weights are attached is formed inside the raised portion 30, the center of gravity of the head can be further lowered. The hitting angle can thereby be increased and the flight distance can be lengthened. Also, the fixing member 7 and the decoration member 6 can be prevented from protruding by being arranged inside the raised portion 30, and thus these members can be prevented from catching on the ground when the club is swung.
(2) The center of the recessed portion 31 is further to the back side in the face-back direction than the center of gravity of the head, and thus the depth of the center of gravity is increased. Furthermore, because the recessed portion 31 is arranged on the heel side in the toe-heel direction, slicing is less likely to occur (so-called “ball holding” improves). Slicing can also be suppressed due to the raised portion 30 being formed to have a triangular shape as described above and being mainly arranged on the heel side of the sole portion 3.
(3) Even if the recessed portion 31 is arranged further to the back side in arranging the recessed portion 31 inside the raised portion 30, the recessed portion 31 can be housed inside the raised portion 30 due to the second edge portion 302 of the raised portion 30 protruding in an arc shape (protruding portion 304). Accordingly, the recessed portion 31 can be arranged on the back side, without impairing the design of the raised portion 30.
(4) The fixing member 7 and the decoration member 6 are both arranged in the recessed portion 31, and therefore the decoration member 6 can also be used as a weight.
(5) In the raised portion 30, the placement region 306 and the rear region 307 are formed in the face-back direction, and the rear region 307 inclines upward from the boundary 309 between both regions. Specifically, the two regions 306 and 307 are connected so as to bend at the boundary therebetween. For this reason, compared to when the two regions 306 and 307 are flatly connected, the rigidity of the raised portion 30 can be enhanced. The frequency of the vibration thereby increases when the ball is hit, and the pitch of the ball hitting sound can be raised. In particular, in the present embodiment, if the fixing member 7 and the decoration member 6 that function as weights are arranged in the vicinity of the antinode of vibration of the raised portion 30, the frequency of the vibration tends to decrease. Accordingly, such a structure is particularly advantageous in that, when an angle is given to the boundary 309 between the placement region 306 and the rear region 307 as described above, the rigidity of the raised portion that receives the vibration caused by hitting the ball is enhanced, and the pitch of the ball hitting sound can be raised.
6. Variations
Although an embodiment of the present invention has been described above, the present invention is not limited to the foregoing embodiment, and various modifications can be made without departing from the gist of the invention. The following are examples of modifications that can be made.
6.1
In the above embodiment, the raised portion 30 is formed to have a triangular shape, but the shape of the raised portion 30 is not particularly limited to this shape, as long as the recessed portion 31 is arranged inside the raised portion 30, and the center of the recessed portion 31 is arranged on the back side in the face-back direction and on the heel side in the toe-heel direction. Also, the height of the rise in the raised portion 30 is not particularly limited, and as described in the aforementioned embodiment, the height of the rise may be changed depending on location or set to a constant height in all places. It is preferable, however, for the raised portion 30 to be arranged on the heel side as a whole.
6.2
In the aforementioned embodiment, the placement region 306 and the rear region 307 are connected at an angle in the raised portion 30, but the regions do not necessarily need to be arranged in this manner, and the regions 306 and 307 may be flat.
6.3
In the aforementioned embodiment, both the fixing member 7 and the decoration member 6 are arranged in the recessed portion 31, but the golf club head according to the present invention is constituted even if only the fixing member 7 is arranged in the recessed portion 31, or even if neither the fixing member 7 nor the decoration member 6 is arranged in the recessed portion 31. Also, a plurality of recessed portions can be provided. Furthermore, the fixing member 7 and the decoration member 6 are not particularly limited in shape or fixing method, as long as they do not extend outside the recessed portion 31. Also, the recessed portion 31 may be other than circular, and may have a polygonal shape. Furthermore, the recessed portion 31 need only be arranged in the raised portion 30, and thus is not necessarily required to protrude from a peripheral portion.
6.4
In the aforementioned embodiment, a wood-type golf club was described, but the golf club according to the present invention is not limited to this. For example, the golf club may have a hollow head, such as so-called utility clubs and hybrid clubs.
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2015-117059 | Jun 2015 | JP | national |
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