U.S. patent application number 10/863253 was filed with the patent office on 2004-11-11 for golf club set.
This patent application is currently assigned to BRIDGESTONE SPORTS CO., LTD.. Invention is credited to Hasebe, Yu.
Application Number | 20040224785 10/863253 |
Document ID | / |
Family ID | 28035061 |
Filed Date | 2004-11-11 |
United States Patent
Application |
20040224785 |
Kind Code |
A1 |
Hasebe, Yu |
November 11, 2004 |
Golf club set
Abstract
As the club number increases so that the loft angle is larger,
the center-of-gravity height HG of each head becomes larger, and
the center-of-gravity depth ZG thereof becomes smaller. Each head
is hollow, and a face portion becomes thicker in its lower portion.
The back bottom thickness T is smaller in an iron shorter in club
length.
Inventors: |
Hasebe, Yu; (Tokyo,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
BRIDGESTONE SPORTS CO.,
LTD.
|
Family ID: |
28035061 |
Appl. No.: |
10/863253 |
Filed: |
June 9, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10863253 |
Jun 9, 2004 |
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10386683 |
Mar 13, 2003 |
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6780123 |
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Current U.S.
Class: |
473/287 ;
473/291 |
Current CPC
Class: |
A63B 53/0408 20200801;
A63B 53/0458 20200801; A63B 53/047 20130101; A63B 53/04 20130101;
A63B 53/0454 20200801; A63B 53/0475 20130101; A63B 60/02 20151001;
A63B 60/00 20151001; A63B 53/045 20200801; A63B 53/005
20200801 |
Class at
Publication: |
473/287 ;
473/291 |
International
Class: |
A63B 053/00; A63B
053/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 14, 2002 |
JP |
P2002-070478 |
Claims
1. (Cancelled).
2. A golf club set comprising: a plurality of iron-type golf clubs
different in club length, each golf club having a head whose loft
angle increases step by step as club length thereof becomes shorter
step by step, wherein as the loft angle of the golf club head of
each golf club increases, center-of-gravity height HG projected on
a face surface of the golf club head becomes larger and
center-of-gravity depth ZG of the golf club head becomes shallower,
wherein center-of-gravity height HGR of the golf club head of each
golf club is constant among the golf clubs.
3.-7. (Cancelled).
8. A golf club set comprising: a plurality of iron-type golf clubs
different in club length, each golf club having a head whose loft
angle increases step by step as club length thereof becomes shorter
step by step, wherein each of golf club heads includes a hollow
portion: and wherein as the loft angle of the golf club head of
each golf club increases, center-of-gravity height HG projected on
a face surface of the golf club head becomes larger and
center-of-gravity depth ZG of the golf club head becomes shallower,
wherein center-of-gravity height HGR of the golf club head of each
golf club is constant among the golf clubs.
9.-12. (Cancelled).
Description
[0001] The present disclosure relates to the subject matter
contained in Japanese Patent Application No. 2002-70478 filed on
Mar. 14, 2002, which is incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an iron golf club set made
up of a plurality of iron golf clubs.
[0004] 2. Description of the Related Art
[0005] In an iron golf club set made up of a plurality of iron golf
clubs different in club length, the loft angle of a head is
increased as the club length is shorter, that is, as the club
number is larger. In addition, in recent years, a hollow golf club
head having a hollow portion for increasing the depth of the center
of gravity to thereby expand the sweet area has been commercially
available.
SUMMARY OF THE INVENTION
[0006] It is an object of the invention to provide an iron golf
club set in which each golf club applies a proper quantity of spin
to a ball in accordance with its club number and it is easy to stop
a ball with a short iron while it is easy to hit a ball high with a
middle iron or a long iron so as to obtain a large carry.
[0007] A golf club set according to the invention includes a
plurality of iron-type golf clubs different in club length, each
golf club having a head whose loft angle increases step by step as
club length thereof becomes shorter step by step. As the loft angle
of the golf club head of each golf club increases,
center-of-gravity height HG projected on a face surface of the golf
club head becomes larger and center-of-gravity depth ZG of the golf
club head becomes smaller.
[0008] In the golf club set according to the invention,
center-of-gravity height HGR of the golf club head of each golf
club may be constant among the golf clubs, or the center-of-gravity
height HGR may be lower as the loft angle is larger.
[0009] In the golf club set according to the invention, the higher
the club number of a club is, the higher the center-of-gravity
height HG of its golf club head is, and the shallower the
center-of-gravity depth ZG thereof is. Thus, it becomes easier to
apply spin to a ball. Incidentally, with a short iron whose club
number is large, a ball (hit ball) is hit sufficiently high by its
large loft angle in spite of its large center-of-gravity height HG.
In this case, importance is attached to the quantity of ball spin
rather than the ball height, and increase in the quantity of ball
spin to thereby make it easy to stop the ball on the green is
favorable for making the score of a golfer better.
[0010] On the other hand, for reducing the rate of missed shots
with a middle iron or a long iron, generally, it is favorable that
the height (height during flight) of a ball rather than the ball
spin is increased to thereby make it easy to secure a large carry.
In the golf club set according to the invention, therefore, as the
club number is smaller, the center-of-gravity height HG is made
lower and the center-of-gravity depth ZG is made deeper. Thus, a
ball is allowed to be hit high easily.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is an exploded perspective view from the rear of a
head used in a golf club according to an embodiment of the
invention.
[0012] FIG. 2 is an exploded perspective view from the front of the
head shown in FIG. 1.
[0013] FIG. 3 is an exploded sectional view taken on line III-III
in FIG. 1.
[0014] FIG. 4A is a longitudinally sectional view of the golf club
head according to the embodiment, and FIG. 4B is a dimensional
drawing of the golf club head.
[0015] FIG. 5 is a sectional view taken on line V-V in FIG. 1,
showing a back portion.
[0016] FIG. 6 is a perspective view from the front of the golf club
head.
[0017] FIG. 7 is a perspective view from the rear of the golf club
head.
[0018] FIG. 8A is a perspective view from the rear of a face
portion of a golf club head according to another embodiment of the
invention, and FIG. 8B is a sectional view taken on line B-B in
FIG. 8A.
[0019] FIG. 9A is a perspective view from the rear of a face
portion of a golf club head according to a further embodiment of
the invention, and FIG. 9B is a sectional view taken on line B-B in
FIG. 9A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] An embodiment of the invention will be described below with
reference to the drawings. FIG. 1 is an exploded perspective view
from the rear of a golf club head according to an embodiment of the
invention. FIG. 2 is an exploded perspective view from the front of
the golf club head according to the embodiment. FIG. 3 is an
exploded sectional view taken on line III-III in FIG. 1. FIG. 4A is
a longitudinally sectional view of the golf club head according to
the embodiment, and FIG. 4B is a dimensional drawing of the golf
club head. FIG. 5 is a sectional view taken on line V-V in FIG. 1,
showing a back portion. FIG. 6 is a perspective view from the front
of the golf club head. FIG. 7 is a perspective view from the rear
of the golf club head.
[0021] This golf club head 1 is an iron head in which a face
portion 10 and a back portion 20 made of metal respectively have
been welded integrally.
[0022] The face portion 10 has a circumferential edge portion 11 in
its back surface. The circumferential edge portion 11 is formed of
a flat surface all over its circumference. In the rear surface of
the face portion 10, a part other than the circumferential edge
portion 11 is formed as a recess portion 12. The face portion 10 is
integrated with a hosel 16.
[0023] In the bottom surface of the recess portion 12, a first
bottom surface 12a which is the deepest, a second bottom surface
12b which is the second deepest, a third bottom surface 12c which
is the third deepest, and a fourth bottom surface 12d which is the
shallowest are formed in descending order. The respective bottom
surfaces 12a to 12d are parallel with the face surface (the front
surface of the face portion 10), and the borders among the
respective bottom surfaces 12a to 12d form steps. Accordingly, the
recess portion 12 becomes shallower stepwise in its lower portion,
and the thickness of the face portion 10 corresponding to the
recess portion 12 becomes thicker stepwise in its lower
portion.
[0024] Three ribs 13, 14 and 15 are provided vertically to extend
through the recess portion 12. The central rib 14 is located on the
rear side in the substantially central portion of the face surface
in the toe-heel direction. The ribs 13 and 15 are located on both
sides of the rib 14, respectively.
[0025] Incidentally, scorelines (grooves) 17 are provided in the
face surface.
[0026] The back portion 20 has a circumferential edge portion 21
formed of a flat surface, and a first recess portion 22 formed as a
part other than the circumferential edge portion 21. Incidentally,
in this embodiment, a second recess portion 23 is provided on the
toe side of the upper portion of the back surface of the back
portion 20, and a small hole 24 is provided in this second recess
portion 23.
[0027] In this back portion 20, the thickness on the rear side of
the first recess portion 22 becomes thicker in a lower portion of
the back portion.
[0028] The circumferential edge portion 21 of the back portion 20
is laid to overlap the circumferential edge portion 11 of the face
portion 10, and the both are welded with each other. Thus, a golf
club head 1 is formed. This golf club head 1 is a hollow head
having a hollow portion 30 formed by joining the recess portion 12
and the first recess portion 22 together.
[0029] A shaft 2 is inserted into the hosel 16 of the golf club
head 1 and fixedly attached thereto by a bonding agent. Thus, a
golf club (iron) is formed. The loft angle of the golf club is not
larger than 43.degree.. That is, the golf club is an iron whose
club number is 9 or smaller.
[0030] In the golf club having the golf club head 1, the center of
gravity is deep because the golf club head 1 is a hollow head. That
is, the distance ZG between the center of gravity G and the face
surface is long. Thus, the sweet area is wide.
[0031] In the golf club head 1, the height HGR or HG of the center
of gravity G can be designed to be low because the face portion 10
is thicker in thickness as approaching to its lower portion.
Incidentally, as shown in FIG. 4B, the height HGR of the center of
gravity G designates the height between a horizontal plane and the
center of gravity G when the golf club is soled on the horizontal
plane. The height HG designates the height between the horizontal
plane and a projected point of the center of gravity G on the face
surface.
[0032] It is preferable that the height HGR of the center of
gravity is not larger than 17.7 mm, particularly 15.5-17.7 mm. It
is preferable that the depth ZG of the center of gravity is 4.3-7
mm, particularly 4.5-6.5 mm.
[0033] When the height HG or HGR of the center of gravity is
reduced, it becomes easy to hit a ball high with a middle iron or a
long iron. Incidentally, such middle irons include a #5 iron, a #6
iron, and a #7 iron or include a #5 iron and a #6 iron, and such
long irons include irons whose club number is 4 or lower (for
example, #2-#4).
[0034] The golf club set according to the invention is, for
example, formed as a set of #2-#9 irons. Incidentally, the #2 iron
or the #3 iron may be excluded from the set, and occasionally, the
#4 iron may be also excluded from the set.
[0035] It is preferable that the loft angle of each golf club
constituting the golf club set is not larger than 43.degree.,
preferably not larger than 42.degree.. It is preferable that the
loft angle is not smaller than 18.degree., particularly not smaller
than 20.degree..
[0036] According to the invention, as the club number is larger,
that is, from the long irons toward the short irons, the length of
the shaft is reduced so that the club length of the golf club is
reduced.
[0037] According to the invention, it is preferable that the
thickness of the upper portion of the face portion, for example,
the thickness a of the first bottom surface 12a, the thickness B of
the upper portion of the back portion 20, and the thickness (top
thickness) t between the upper end of the hollow portion 30 and the
golf club head top surface are increased as the club number is
larger. When the thickness of the upper portion of the golf club
head is increased as the club number is larger, the height HG of
the center of gravity is increased correspondingly. Thus, back spin
can be applied to a ball with a short iron easily enough to make it
easy to stop the ball falling on the green.
[0038] Incidentally, the loft angle of the short iron is
sufficiently large so that the ball is hit high enough in spite of
the large height HG of the center of gravity. Although the loft
angle is reduced in an iron longer in club length, the height HG of
the center of gravity becomes small so that the launch angle of a
ball becomes high enough to make it easy to hit a ball high. In
addition, as the height HG of the center of gravity becomes
smaller, the spin applied to the ball is reduced to increase a run
after the ball falls. However, long irons are often used not to
apply spin to a ball to thereby stop the ball on the green but to
hit a ball out in an intended direction with a good orientation and
roll the ball from short of the green to thereby make the ball on
the green. It is therefore more important to increase the launch
angle of a hit ball to thereby obtain an intended carry than to
increase the spin.
[0039] According to the invention, the height HGR of the center of
gravity of one golf club head may be made equal to that of another
club even if those clubs have different club numbers.
Alternatively, the height HGR of the center of gravity may be
increased as the club number increases. Even when the height HGR of
the center of gravity is constant among the golf clubs different in
club number, the height HG of the center of gravity can be made
higher as the club number is larger. This is because the larger the
club number of the club is, the larger the loft angle of the club
is.
[0040] In order to apply spin to a ball more easily with an iron
shorter in club length, it is preferable to make a design such that
the thickness (back bottom thickness) T of the intersecting portion
of the back portion and the sole portion is narrower in an iron
shorter in club length. The smaller the back bottom thickness T is,
the higher the height HG of the center of gravity is, and the
shallower the depth ZG of the center of gravity is. In this
embodiment, the intersecting portion is defined as a point E where
the sole width S is maximal, and the thickness T of the
intersecting portion is defined as a shortest distance between the
point E and the inner surface of the hollow portion 30. The point E
is defined as a point at the rear end of the head where a plane
parallel to the face surface first comes in contact with the back
portion when the parallel plane is made to approach the back
portion from behind. The sole width S is a distance between the
parallel plane including the point E and the face surface.
[0041] In order to apply spin to a ball easily, it is also
preferable that the depth ZG of the center of gravity is made
shallower in an iron shorter in club length. According to the
invention, it is preferable that the depth ZG of the center of
gravity is 4.3-7 mm, particularly 4.5-6.5 mm.
[0042] According to the invention, it is preferable that the
thicknesses are changed whenever the club number is increased by
one. However, for example, the thicknesses may be set as follows.
That is, the thicknesses are fixed among a group of long irons (for
example, #2, #3 and #4), the thicknesses are fixed among a group of
middle irons (for example, #5, #6 and #7 or #5 and #6), and the
thicknesses are fixed among a group of short irons (for example, #8
and #9 or #7, #8 and #9). Then, the thicknesses are changed among
the long iron group, the middle iron group and the short iron
group.
[0043] Although the thickness of the face portion is changed in the
four stages of the first to fourth bottom surfaces in the
embodiment, it may be changed in three stages or in five or more
stages. From the point of view of easiness to produce, three to six
stages are preferable. From the point of view of easiness to adjust
the center of gravity, about four or five stages are preferable.
Two stages are not enough to adjust the center of gravity.
[0044] It is preferable that the thickness of the first bottom
surface in the upper portion of the face portion is about 1-2 mm.
It is preferable that the thickness of the n-th bottom surface in
the lowest portion is about 2.5-3.5 mm. It is preferable that the
thickness of the n/2-th (or integer closest to n/2) bottom surface
near the midpoint is about 1.5-3 mm. It is preferable that the sole
width S is about 15-20 mm. It is preferable that the thickness B of
the upper portion of the back portion is about 1-2 mm.
[0045] According to the invention, the thickness of the face
portion may be changed gradually from the toe side to the heel
side. For example, it can be considered that a long iron is
designed so that the thickness is increased on the toe side while
the thickness is reduced on the heel side; a middle iron is
designed so that the face thickness is made substantially uniform
between the toe side and the heel side; and a short iron is
designed so that the thickness is reduced on the toe side while the
thickness is increased on the heel side. Alternatively, the
thickness may be changed in a contrary way. When the design of the
center of gravity is made by changing the thickness in the above
mentioned manner, the easiness to turn over the gold club head can
be adjusted so that the design of golf club heads can be made for
each swing type.
[0046] According to the invention, a similar change may be made on
the thickness of the back portion from the toe side to the heel
side.
[0047] According to the invention, a visco-elastic polymer, an
adhesive material, a foamable resin, or a visco-elastic resin may
be poured into the hollow portion 30 through the small hole 24. In
addition, a chip may be fitted into the second recess portion 23 or
a resin mold may be applied thereto so as to close the small hole
24 while an indication item such as a trade mark or a part number
is formed in the second recess portion 23.
[0048] Metal forming the golf club head may have a specific gravity
of about 6-9. Specific examples of such metals include steels such
as soft iron, marageing steel and stainless steel, and copper
alloys such as beryllium copper and bronze.
[0049] Incidentally, since the ribs 13, 14 and 15 are provided in
the golf club head 1 according to this embodiment, the feeling of
hitting a ball can be adjusted subtly. In order to make it possible
to adjust the feeling of hitting a ball subtly, a thick portion 40
or 41 may be provided, in place of the ribs, in the central portion
of the back surface of the face portion in the toe-heel direction
as shown in FIGS. 8A and 8B or FIGS. 9A and 9B.
[0050] In a face portion 10A in FIGS. 8A and 8B, the thick portion
40 at the same level as the fourth bottom surface 12d crosses the
third bottom surface 12c upward, and extends halfway up the second
bottom surface 12b. The second and third bottom surfaces 12b and
12c on both sides of the thick portion 40 have the same structures
as those in FIGS. 1-7.
[0051] According to the invention, the thick portion 40 may be
provided to be longer than that in FIGS. 8A and 8B, for example, to
reach the first bottom surface 12a. On the contrary, the thick
portion 40 may be provided to be shorter than that in FIGS. 8A and
8B, for example to be present only in the third bottom surface 12c.
The thick portion 40 may be thicker than the illustrated one, for
example, may be formed to rise from the fourth bottom surface
12d.
[0052] In a face portion 10B in FIGS. 9A and 9B, the thick portion
41 is provided continuously between the upper end of the recess
portion 12 and the lower end thereof. The thickness of the face
portion 10B in the thick portion 41 becomes larger in its lower
portion as shown in FIG. 9B. The back surface of the thick portion
41 becomes a slope inclined to the bottom surfaces 12a to 12d of
the recess portion 12.
[0053] The other configurations of the face portions 10A and 10B in
FIGS. 8A and 8B and FIGS. 9A and 9B are the same as the face
portion 10 described previously. Each of the face portions 10A and
10B is also welded with the back portion so as to form a golf club
head.
[0054] When such a thick portion 40 or 41 is provided, a response
can be felted particularly by a senior golfer as if a ball hit by
the golfer were crushed.
EXAMPLE
[0055] Description will be made below on an example of the
invention and a comparative example. A golf club head, as shown in
FIGS. 1-7, was made of stainless steel whose specific gravity was
7.8. The face portion and the back portion were formed separately
from each other by casting in a lost-wax process, and they were
welded integrally with each other. The ribs 13, 14 and 15 on the
back surface of the face surface were set at 4.2 mm in thickness
and 2.2 mm in width. The interval between the ribs was set at 11
mm. The thicknesses a, b, c and d of the face surface, the top
thickness t and the back bottom thickness T are shown in Table 1.
The depth ZG of the center of gravity, the heights HGR and HG of
the center of gravity and the sole width S of each golf club head
are shown together in Table 1.
[0056] As a comparative example, a golf club set was made up in the
same manner as that in Example 1, except that the recess portion 12
was set to have a uniform depth (face thickness 3.5 mm), and no rib
was provided.
1 TABLE 1 (unit other than loft angle: mm) Example Comparative
Example Number #3 #5 #7 #9 #3 #5 #7 #9 loft angle 20.5.degree.
26.degree. 34.degree. 42.degree. 20.5.degree. 26.degree. 34.degree.
42.degree. face thickness a 1.5 1.6 1.8 2.2 3.5 3.5 3.5 3.5 face
thickness 1.8 2.0 2.2 2.4 3.5 3.5 3.5 3.5 b face thickness c 2.6
2.6 2.6 2.7 3.5 3.5 3.5 3.5 face thickness 3.4 3.2 3.2 3.2 3.5 3.5
3.5 3.5 d top thickness t 1.5 1.6 1.6 2.2 3.5 3.5 3.5 3.5 back
bottom 10.5 9.5 8.5 5.5 7 8.5 8.5 10 thickness T depth (Zg) of 6.2
5.4 5 4.7 4.1 3.9 3.5 3.0 center of gravity height (Hgr) of 16.4
17.2 17.4 17.7 18.8 18.4 18.0 17.8 center of gravity height (Hg) of
18.6 19.7 20.4 21.1 20.3 20.2 20.1 20.0 center of gravity maximum
sole 18.7 18.7 18 18 19.6 19.3 19.8 19.2 width
[0057] Practical shots were hit with the golf clubs, and evaluation
was performed thereon.
[0058] First, in the evaluation with the #3 iron, it was easier to
hit a ball high with the club according to the invention than with
the club in the comparative example. In addition, the feeling of
hitting the ball with the club according to the invention was
steadier than with the club in the comparative example. Further,
the #9 iron according to the invention was evaluated to be
preferred to that according to the comparative example because the
quantity of back spin was larger so that the ball was stopped
easily on the green. In addition, each iron head according to the
invention had a usual iron head shape in appearance. Accordingly,
each of the irons according to the invention was evaluated as
"there is no uncomfortable feeling with the club at the ready.",
"the club head is preferably easy to handle because it is not as
large as a utility club head.", and "as the set, each club shows a
function corresponding to its own club number preferably while
having a usual iron shape."
[0059] As described above, according to the invention, a golf club
head easy to hit a ball high and a golf club set provided with such
golf club heads are provided. According to the invention, design
can be made so that the launch angle is high enough to hit a ball
high with a middle iron or a long iron while the spin is great
enough to stop a ball easily with a short iron.
* * * * *