U.S. patent application number 10/537609 was filed with the patent office on 2006-03-23 for golf club head and golf club.
Invention is credited to Tomoaki Mori, Norihiko Nakahara, Yoh Nishizawa.
Application Number | 20060063605 10/537609 |
Document ID | / |
Family ID | 32500800 |
Filed Date | 2006-03-23 |
United States Patent
Application |
20060063605 |
Kind Code |
A1 |
Nakahara; Norihiko ; et
al. |
March 23, 2006 |
Golf club head and golf club
Abstract
The inner surface of the hollow portion of the golf club head
according to the present invention includes either or both of a
concave surface and a flat surface. On the other hand, the
projecting portion provided on the inner surface of the hollow
portion, if any, is so formed that it has a convex surface with a
radius of curvature equal to or greater than 3 mm, or chamfered at
a level of C3 or more (JIS B0701-1987 standard). Owing to such
structure, the golf club head can be manufactured with good
efficiency even if the molding is performed using a bladder because
the rate of molding failure upon such molding is reduced while the
characteristics of the golf club head are ensured. The golf club of
the present invention has such a golf club head as above.
Inventors: |
Nakahara; Norihiko;
(Kanagawa, JP) ; Mori; Tomoaki; (Kanagawa, JP)
; Nishizawa; Yoh; (Kanagawa, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
32500800 |
Appl. No.: |
10/537609 |
Filed: |
December 8, 2003 |
PCT Filed: |
December 8, 2003 |
PCT NO: |
PCT/JP03/15668 |
371 Date: |
June 3, 2005 |
Current U.S.
Class: |
473/305 ;
473/324; 473/345; 473/349 |
Current CPC
Class: |
A63B 2053/0491 20130101;
B29L 2031/5227 20130101; A63B 53/0466 20130101; A63B 53/0437
20200801; A63B 53/0433 20200801; A63B 53/0475 20130101; A63B
2209/02 20130101; B29C 70/44 20130101; B29C 70/68 20130101; A63B
60/02 20151001 |
Class at
Publication: |
473/305 ;
473/324; 473/345; 473/349 |
International
Class: |
A63B 53/02 20060101
A63B053/02; A63B 53/04 20060101 A63B053/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 6, 2002 |
JP |
2002-355806 |
Claims
1. A method for manufacturing a golf club head which comprises
outer shell members and a hollow portion surrounded by the outer
shell members, comprising the steps of: integrating first outer
shell members to form a face portion, a side portion and a sole
portion, in which a projecting portion is provided on an inner
surface of the hollow portion; and setting a second outer shell
member on the integrated first outer shell members to form the
hollow portion and bonding the second outer shell member to the
integrated first outer shell members by applying pressure from
inside to outside of the the hollow portion on inner surfaces of
the first integrated outer shell members and the second outer shell
member, thereby forming a crown portion of the golf club head,
wherein the projecting portion is formed so as to have a convex
surface with a radius of curvature equal to or greater than 3 mm,
or the projecting portion is chamfered by chipping off a corner
edge of an angular portion, where two surfaces of the projecting
portion intersect at an angle, by 3 mm or more along the two
surfaces, before the second outer shell member is bonded to the
first integrated outer shell members.
2. The method according to claim 1, wherein the convex surface is
formed by using a sheet member comprising a resin on a surface of
the projecting portion.
3. The method according to claim 2, wherein the sheet member
comprises a fiber reinforced resin material.
4. (canceled)
5. The method according to claim 1, wherein a columnar neck member
having a shaft insertion hole into which a golf club shaft is
inserted, is provided to the first outer shell members, the hole
being closed at one end, wherein the neck member projects into the
hollow portion and its end on a projection side is so formed that
the end has a convex surface with a radius of curvature equal to or
greater than 3 mm, or chamfered by chipping off a corner edge of an
angular portion, where two surfaces of the end on the projection
side intersect at an angle, by 3 mm or more along the two
surfaces.
6. The method according to claim 5, wherein a lateral surface of
the columnar neck member on a heel side is joined to the first
outer shell members and the lateral surface on the heel side is
covered with a joining surface of the first outer shell members so
that a concave space may not be formed between the lateral surface
on the heel side and the first outer shell members within the
hollow portion.
7. A golf club head comprising an outer shell member and a hollow
portion surrounded by the outer shell member, wherein: an inner
surface of the hollow portion includes either or both of a concave
surface and a flat surface and the inner surface has no projecting
portion formed thereon.
8. A golf club which has a grip, a golf club shaft, and a golf club
head, wherein: the golf club head comprises an outer shell member
and a hollow portion surrounded by the outer shell member; an inner
surface of the hollow portion includes either or both of a concave
surface and a flat surface and a projecting portion is formed on
the inner surface; and the projecting portion is so formed that it
has a convex surface with a radius of curvature equal to or greater
than 3 mm, or chamfered by chipping off a corner edge of an angular
portion, where two surfaces of the projecting portion intersect at
an angle, by 3 mm or more along the two surfaces.
9. A golf club which has a grip, a golf club shaft, and a golf club
head, wherein: the golf club head comprises an outer shell member
and a hollow portion surrounded by the outer shell member; and an
inner surface of the hollow portion includes either or both of a
concave surface and a flat surface and the inner surface has no
projecting portion formed thereon.
Description
TECHNICAL FIELD
[0001] The present invention relates to a golf club head provided
with a hollow portion which is surrounded by an outer shell member
and to a golf club having such a golf club head.
Prior Art
[0002] It has come to be known in recent years that a coefficient
of restitution of a golf ball can be increased by using a titanium
alloy or the like in the golf ball-striking surface of a hollow
golf club head made of metal. In addition, the coefficient of
restitution can be increased by making a face member that
constitutes the striking surface thinner, or by making a joining
edge portion where the face member joins to another member such as
a crown member or a sole member partially thinner. An outer shell
member of such golf club head is formed by a method in which
members made from substantially similar metallic materials are
joined together by welding, brazing, and so forth.
[0003] On the other hand, an internal pressure molding method is
also known. An outer shell member of a golf club head is placed in
a predetermined molding die, a bag or bladder is inserted within a
hollow portion of the golf club head that is surrounded by the
outer shell member, and an internal pressure is imparted to the
bladder with high temperature air introduced in the bladder, thus
expanding the bladder and applying a pressure from the inside of
the hollow portion. The outer shell member can thus be molded into
a predetermined shape. The term "bladder" refers to a bag-like
element composed of a freely expandable nylon material or the like.
Air can be filled into such a bladder at a predetermined
temperature so as to mold the outer shell member of a golf club
head into a desired shape.
[0004] However, with the internal pressure molding method, small
holes are formed in the inserted bladder during a long use, thus
causing air leaks, depending upon the structure of the golf club
head to be manufactured. Accordingly, a predetermined internal
pressure is not reached, and the outer shell member cannot be
molded into the desired shape, causing a problem of molding
defects.
[0005] There is also a production problem in that such defects of a
bladder are not visible. There are many cases where lots of
manufactured golf club heads must then be treated as defective
units since defects in a bladder only come to light by examining
molded golf club heads one by one after manufacturing golf clubs in
a large quantity.
[0006] In order to solve the problems described above, an object of
the present invention is to provide a golf club head in which the
rate of molding failure upon molding by using a bladder can be
lowered so that the golf club head can be manufactured with good
efficiency while ensuring the characteristics of a golf club head
having a hollow portion and to provide a golf club which has such a
golf club head.
DISCLOSURE OF THE INVENTION
[0007] The present invention provides a golf club head comprising
an outer shell member and a hollow portion surrounded by the outer
shell member, wherein: an inner surface of the hollow portion
includes either or both of a concave surface and a flat surface and
a projecting portion is formed on the inner surface; and the
projecting portion is so formed that it has a convex surface with a
radius of curvature equal to or greater than 3 mm, or chamfered by
chipping off a corner edge of an angular portion, where two
surfaces of the projecting portion intersect at an angle, by 3 mm
or more along the two surfaces.
[0008] The projecting portion as above is assumed to be a convex
portion projecting from the surface of the hollow portion by 3 mm
or more. A metallic mass for adjusting the center of gravity
provided on a sole portion, a part of a neck portion projecting
into the hollow portion, or the like corresponds to the projecting
portion. The expression "chamfered by chipping off by 3 mm or more"
should be understood to mean the chamfering at a level of "C3 or
more" as defined by the JIS B0701-1987 standard.
[0009] The convex surface is provided by using, for instance, a
sheet material comprising a resin for the surface of the projecting
portion. The sheet material may comprise a fiber reinforced resin
material.
[0010] The outer shell member is formed by joining at least two
members together by bonding and the members are joined together by
bonding preferably when the outer shell member is molded by an
application of a pressure from the inside of the hollow portion
toward the outside.
[0011] Preferably, the golf club head further comprises a columnar
neck member having a shaft insertion hole into which a golf club
shaft is inserted, the hole being closed at one end, wherein the
neck member projects into the hollow portion and its end on a
projection side is so formed that the end has a convex surface with
a radius of curvature equal to or greater than 3 mm, or chamfered
by chipping off a corner edge of an angular portion, where two
surfaces of the end on the projection side intersect at an angle,
by 3 mm or more along the two surfaces.
[0012] In that case, it is more preferable that a lateral surface
of the columnar neck member on a heel side is joined to the outer
shell member and covered with a joining surface of the outer shell
member so that a concave space may not be formed between the
lateral surface on the heel side and the outer shell member within
the hollow portion.
[0013] The lateral surface of the neck member on the heel side is
to be understood as the heel-side half of the lateral surface of
the columnar neck member as evenly divided into two halves on the
heel side and the toe side.
[0014] The present invention also provides a golf club head
comprising an outer shell member and a hollow portion surrounded by
the outer shell member, wherein an inner surface of the hollow
portion includes either or both of a concave surface and a flat
surface and the inner surface has no projecting portion formed
thereon.
[0015] The present invention further provides a golf club which has
a grip, a golf club shaft, and a golf club head, wherein: the golf
club head comprises an outer shell member and a hollow portion
surrounded by the outer shell member; an inner surface of the
hollow portion includes either or both of a concave surface and a
flat surface and a projecting portion is formed on the inner
surface; and the projecting portion is so formed that it has a
convex surface with a radius of curvature equal to or greater than
3 mm, or chamfered by chipping off a corner edge of an angular
portion, where two surfaces of the projecting portion intersect at
an angle, by 3 mm or more along the two surfaces.
[0016] The present invention also provides a golf club which has a
grip, a golf club shaft, and a golf club head, wherein: the golf
club head comprises an outer shell member and a hollow portion
surrounded by the outer shell member; and an inner surface of the
hollow portion includes either or both of a concave surface and a
flat surface and the inner surface has no projecting portion formed
thereon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is an exploded perspective view schematically showing
an embodiment of the golf club head which the golf club of the
present invention has.
[0018] FIG. 2A shows a section A-A of the golf club head of FIG. 1,
taken along a line A-A.
[0019] FIG. 2B shows a section A'-A' of the golf club head of FIG.
1, taken along a line A'-A'.
[0020] FIG. 2C is an illustrative diagram showing another example
of the projecting portion.
[0021] FIG. 3 is a partial cross-sectional view of the golf club
head shown in FIG. 2B, taken along a line B-B.
[0022] FIG. 4 is a diagram for explaining internal pressure molding
carried out during the manufacture of the golf club head of the
present invention.
[0023] FIG. 5 is a sectional view showing the structure of another
embodiment of the golf club head of the present invention.
[0024] FIG. 6 is a sectional view showing a golf club head
structure other than that shown in FIG. 2B.
BEST MODE OF IMPLEMENTING THE INVENTION
[0025] The golf club head of the present invention is described in
detail below based on preferred embodiments shown in the
accompanying drawings.
[0026] FIG. 1 is an exploded perspective view schematically showing
a golf club 1 which has a golf club head 10 that is an embodiment
of the golf club head of the present invention.
[0027] The golf club 1 has the golf club head 10, a golf club shaft
2, a grip 4 and a socket 6. The golf club head 10 is connected to
one end of the golf club shaft 2 through the socket 6. The grip 4
is provided at the other end of the golf club shaft 2.
[0028] The golf club head 10 as shown in FIG. 1 is provided with a
face portion that strikes a golf ball, a crown portion that is
connected to the face portion, and a sole portion that is connected
to the face portion, and has a crown member 12 that forms the major
part of the crown portion, a side member 14 that mainly forms the
side portion, a sole member 16 that forms the sole portion, and a
face member 18 that mainly forms the face portion and is provided
with a golf ball-striking surface, each as an outer shell
component, as well as a columnar neck member 20 that has a shaft
insertion hole 19 closed at one end, into which the golf club shaft
2 is inserted.
[0029] The side member 14, the sole member 16, and the face member
18 are integrated with one another by welding in advance. In the
side member 14, an extension portion 22 is provided which has an
edge curving to a crown portion side, extending to the crown
portion and forming a part of the crown portion. In the face member
18, an extension portion 24 is provided which has an edge curving
to the crown portion side, extending to the crown portion and
forming a part of the crown portion. That is, the side member 14,
the sole member 16, and the face member 18 are previously
integrated with one another to become a state as shown in FIG. 1.
The crown member 12 is then joined to the extension portions 22 and
24 by using an adhesive, the golf club head 10 being thus
constructed.
[0030] Various types of alloy materials may be used for the side
member 14, the sole member 16, and the face member 18, such as a
titanium alloy, an aluminum alloy, or a stainless steel alloy.
[0031] The crown member 12 is structured by using a composite
material in which a plurality of layers of a carbon fiber
reinforced plastic material having different orientation angles are
laminated together. An epoxy resin, an unsaturated polyester resin,
a vinyl ester resin, or the like may be used as a matrix. It should
be noted that reinforcing fibers other than carbon fibers, such as
glass fibers, aramid fibers, and PBO
(poly(p-phenylene-benzobisoxazole)) fibers, may also be used in the
present invention. In addition, various types of alloy materials,
such as magnesium alloys, aluminum alloys, and titanium alloys, may
also be used in the crown member 12, apart from composite
materials.
[0032] FIG. 2A shows a section A-A of the golf club head 10 of FIG.
1, taken along a line A-A. FIG. 2B shows a section A'-A' of the
golf club head 10 of FIG. 1, taken along a line A'-A'. FIG. 3 is a
partial cross-sectional view of the golf club head 10 shown in FIG.
2B, taken along a line B-B (line perpendicular to the central axis
of the shaft insertion hole 19).
[0033] As shown in FIG. 2A, a hollow portion 26 is formed in the
golf club head 10, as being surrounded by the crown member 12, the
side member 14, and the sole member 16. A metallic mass 28 for
adjusting the center of gravity is provided in a surface of the
sole member 16 in the hollow portion 26 as a projecting portion
that projects into the hollow portion 26. An angular portion of the
metallic mass 28 is formed by a surface (curved surface) having a
radius of curvature equal to or greater than 3 mm. It should be
noted that the term "projecting portion that projects into the
hollow portion 26" refers to a portion that projects from a surface
of the outer shell member comprising the crown member 12, the side
member 14, and the sole member 16 by 3 mm or more perpendicularly
to a region of the surface in the neighborhood of the portion.
[0034] Further, the neck member 20 projects into the hollow portion
26. As shown in FIG. 2B, the lateral surface of the neck member 20
on the heel side is welded to the side member 14, and is thus
integral with the outer shell member comprising the crown portion
12, the side member 14, and the sole member 16. The welding of the
neck member 20 to the side member 14 is performed so that a narrow
concave space may not be formed between the lateral surface of the
neck member 20 on the heel side and the side member 14. As shown in
FIG. 3, the lateral surface of the neck member 20 on the heel side
is covered with a joining surface 14a of the side member 14. In
addition, an end portion 20a of the neck member 20 on the
projection side is formed by a curved surface having a radius of
curvature equal to or greater than 3 mm.
[0035] According to the present invention, it is also possible to
chamfer the angular portions of the projecting portion and the end
portion of the neck member on the projection side at a level of C3
or more instead of forming the projecting portion and the end of
the neck member on the projection side so that they may have a
surface with a radius of curvature equal to or greater than 3 mm as
described above. The denotation "C3" indicates that chamfering is
carried out by chipping off the corner edge of an angular portion,
where two surfaces intersect at an angle, by 3 mm along the two
surfaces. Accordingly, the chamfering at a level of "C3 or more" is
carried out by chipping off the corner edge of an angular portion
by 3 mm or more along the two intersecting surfaces. Such
chamfering is defined by the JIS B0701-1987 standard.
[0036] The golf club head 10 is thus structured.
[0037] The projecting portion that projects into the hollow portion
of the golf club head of the present invention may also be made by
covering the surface of a projecting member with a sheet member so
as to obtain a projecting portion having a radius of curvature
equal to or greater than 3 mm, as shown in FIG. 2C. By using a
sheet member comprising a fiber reinforced plastic material, for
instance, the projecting portion having a curved surface with a
radius of curvature equal to or greater than 3 mm is obtained
during the molding of the outer shell member. It should be noted
that the present invention is not limited to wood-type golf club
heads but applied to any golf club head as long as it has a hollow
structure.
[0038] The golf club head 10 as described above is obtained by
integrating the side member 14, the sole member 16, and the face
member 18 with one another by welding in advance as shown in FIG.
1, and then joining the crown member 12 with the extension portions
22 and 24 by using an adhesive.
[0039] Internal pressure molding is then performed as shown in FIG.
4.
[0040] Specifically, the golf club head 10, in a state where the
bonded joining surfaces are partially dry, is disposed in a
predetermined molding die 30. A pipe 34 having a nylon bladder 32
at its one end is inserted into the hollow portion 26 from a
through hole 16a formed in the sole member 16. The pipe 34 is
connected to a supply apparatus that supplies high temperature air,
and supplies a desired amount of air at a desired temperature. The
through hole 16a that is formed in the sole member 16 is closed
with a closing member after internal pressure molding.
[0041] As shown in FIG. 4, high temperature air, for example, air
at 150.degree. C., is supplied within the bladder 32 up to nearly 5
(kgf/cm.sup.2) to cause the bladder 32 to expand within the hollow
portion 26 and, in addition, cause the outer shell member composed
of the crown member 12, the side member 14, the sole member 16, and
the face member 18 to expand. In this respect, angular portions 28a
and 28b of the metallic mass 28 and the end portion 20a of the neck
member 20 are formed by surfaces having a radius of curvature equal
to or greater than 3 mm, the shaft insertion hole 19 of the neck
member 20 projecting into the hollow portion 26 is closed at the
end on the projection side, and, moreover, a narrow concave space
is not formed between the lateral surface of the neck member 20 on
the heel side and the side member 14, so that there are no
protrusions or recesses within the hollow portion 26 which may
cause defects in the freely expandable bladder 32. The probability
of defects occurring in the bladder 32 can thus be made low.
[0042] Since the outer shell member is disposed in the molding die
30 at this point, its expansion is restrained in accordance with
the shape of the inner surface of the molding die 30 and, in
consequence, the outer shell member assumes the shape corresponding
to that of the inner surface of the molding die 30. For example,
the crown member 12 composed of a composite material is molded into
the shape corresponding to that of the inner surface of the molding
die 30 as a result of the deformation due to heat and pressure. At
the same time, a joining surface of the crown member 12 and joining
surfaces of the extension portions 22 and 24 are pressed in a high
temperature state so that the curing of an adhesive is promoted
under pressure and the crown member 12 is strongly bonded to the
side member 14 and the face member 18.
[0043] The crown member 12 is joined with the side member 14 and
the face member 18 by bonding in the embodiment described above.
However, there are no particular limitations in the present
invention to members that are to be joined by bonding. For example,
the sole member 16 may also be joined with the side member 14 and
the face member 18 by bonding.
[0044] In addition, in the golf club head of the present invention,
the surface of the hollow portion which is located inside the head,
as being surrounded by the outer shell member, may be formed by a
concave surface or a flat surface.
[0045] FIG. 5 shows another embodiment of the golf club head of the
present invention.
[0046] A golf club head 50 shown in FIG. 5 is structured such that
a surface of a hollow portion 52 is formed by concave surfaces 54a
through 54d and flat surfaces 56a and 56b, and a neck member 58
does not project into the hollow portion 52.
[0047] The probability of defects occurring in a bladder can be
reduced also when the golf club head 50 having the above structure
is molded using a bladder as described above because no protrusions
or recesses exist within the hollow portion 52 which may develop
defects in a freely expandable bladder.
EXAMPLES
[0048] Hollow golf club heads of a structure as shown in FIG. 1
were manufactured and the rate of failure in golf club head molding
was determined.
[0049] The crown member 12 used for the manufacture was structured
by using a composite material in which four layers of a carbon
fiber reinforced plastic material were laminated. The side member
14, the sole member 16, and the face member 18 were structured by
using a titanium alloy material. After welding the side member 14,
the sole member 16, and the face member 18 together, these members
were bonded to the crown member 12 by using a specified adhesive.
The golf club head thus fabricated was expanded from the inside and
molded by using the bladder 32 as shown in FIG. 4.
[0050] For the golf club heads manufactured as Examples 1, 2 and 3
as well as Comparative Examples 1 and 2, the specifications as
shown in Tables 1 and 2 below had been set.
[0051] In Examples 1 and 2, edge removal from the projecting
portion was carried out by rounding off the angular portion of the
projecting portion so as to allow the projecting portion to have a
surface with a radius of curvature equal to or greater than 3 mm.
In Example 3, a sheet member comprising a fiber reinforced plastic
material (FRP sheet) was used to allow the projecting portion to
have a curved surface with a radius of curvature equal to or
greater than 3 mm as shown in FIG. 2C, the edge removal from the
projecting portion being thus effected. Joining of the neck member
was performed in two ways as follows. Specifically, the joining was
carried out such that the lateral surface of the neck member 20
projecting into the hollow portion 26 was covered with the joining
surface of the side member 14 entirely on the heel side according
to the embodiment as shown in FIG. 3 so that a narrow concave space
might not be formed between the lateral surface of the neck member
20 on the heel side and the side member 14, as described before.
According to another embodiment as shown in FIG. 6, the lateral
surface of a neck member 62 projecting into a hollow portion 60 was
joined with the joining surface of a side member 64 partly on the
heel side. TABLE-US-00001 TABLE 1 Edge removal Shaft Joining of
Molding from projecting insertion neck failure portion hole member
rate (%) Example 1 Removed Closed 0.5 Example 2 Removed Closed 1
Comparative Not removed Closed 7 Example 1 Comparative Not removed
Through 15 Example 2
[0052] TABLE-US-00002 TABLE 2 Edge removal Shaft Joining of Molding
from projecting insertion neck failure portion hole member rate (%)
Example 3 Removed Closed 0.6 (FRP sheet)
[0053] Five types of golf club heads whose specifications were as
shown in the tables were manufactured, four hundred each in number,
and the defectively molded heads were counted. The molding failure
rate (%) was determined as shown in Table 1.
[0054] The term "defectively molded" or "molding failure" means
that the crown member is incompletely joined by bonding because of
the defects (holes) developed in the bladder 32 as shown in FIG. 4
that lead to the failure in molding under a predetermined inner
pressure. The molding failure as such can be found out by checking
whether or not air bubbles are generated from the joining surface
of the crown member when the manufactured golf club head is
immersed in water.
[0055] As seen from Tables 1 and 2, the rate of molding failure was
extremely low in Examples 1, 2 and 3 compared to the rate of
molding failure in Comparative Examples 1 and 2, which indicates
that efficient manufacturing was accomplished for the three
Examples. Further, the metallic mass used for adjusting the center
of gravity can be provided in the hollow portion, similar to a
conventional golf club head, and therefore the characteristics of
the golf club head do not change.
[0056] The golf club head of the present invention has been
described in detail above. However, the present invention is not
limited to the above Examples. It is, of course, also possible to
make various types of modifications and changes without deviating
from the gist of the present invention.
INDUSTRIAL APPLICABILITY
[0057] As described in detail above, according to the present
invention, the surface of the hollow portion of the golf club head
includes either or both of a concave surface and a flat surface. On
the other hand, the projecting portion provided on the surface of
the hollow portion, if any, is so formed that it has a convex
surface with a radius of curvature equal to or greater than 3 mm,
or chamfered at a level of C3 or more. In consequence, the golf
club head can be manufactured with good efficiency even if the
inner pressure molding is performed using a bladder because the
rate of molding failure upon such molding is reduced while the
characteristics of the golf club head are ensured.
* * * * *