U.S. patent application number 10/301866 was filed with the patent office on 2003-09-25 for iron type golf club head.
This patent application is currently assigned to BRIDGESTONE SPORTS CO., LTD.. Invention is credited to Shimazaki, Hideo.
Application Number | 20030181259 10/301866 |
Document ID | / |
Family ID | 27641637 |
Filed Date | 2003-09-25 |
United States Patent
Application |
20030181259 |
Kind Code |
A1 |
Shimazaki, Hideo |
September 25, 2003 |
Iron type golf club head
Abstract
An iron type golf club head including a face portion having a
planar face surface, and a hosel portion connected to the heel side
of the face portion. A shaft insertion hole is provided in the
hosel portion so as to penetrate the hosel portion. The distance
from the center of gravity is 28-33 mm, the height of the center of
gravity is 12-21 mm, the depth of the center of gravity is 5-15 mm,
and the goose distance is 4-15 mm.
Inventors: |
Shimazaki, Hideo; (Tokyo,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 Pennsylvania Avenue, NW
Washington
DC
20037-3213
US
|
Assignee: |
BRIDGESTONE SPORTS CO.,
LTD.
|
Family ID: |
27641637 |
Appl. No.: |
10/301866 |
Filed: |
November 22, 2002 |
Current U.S.
Class: |
473/350 ;
473/314; 473/338; 473/349 |
Current CPC
Class: |
A63B 53/047 20130101;
A63B 53/0408 20200801; A63B 2053/0491 20130101; A63B 60/02
20151001; A63B 53/0433 20200801; A63B 53/0416 20200801 |
Class at
Publication: |
473/350 ;
473/314; 473/338; 473/349 |
International
Class: |
A63B 053/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 8, 2002 |
JP |
P2002-001540 |
Claims
What is claimed is:
1. An iron type golf club head comprising: a face portion having a
face surface; a hosel portion connected to a heel side of the face
portion; and a sole portion; wherein a loft angle is 15-25.degree.;
wherein a distance from a center of gravity is 28-33 mm; and height
of the center of gravity is 12-21 mm.
2. The golf club head according to claim 1, wherein depth of the
center of gravity from the face surface is 5-15 mm.
3. The golf club head according to claim 1, wherein a goose
distance is 4-15 mm.
4. The golf club head according to claim 1, wherein the face
portion has a circumferential edge portion and an inside portion;
wherein the circumferential edge portion and the inside portion are
made of different materials; and wherein specific gravity of the
material of the inside portion is smaller than specific gravity of
the material of the circumferential edge portion.
5. The golf club head according to claim 1, wherein a high specific
gravity member is provided in the sole portion; and wherein the
high specific gravity member is disposed near or behind a
longitudinal midpoint of the sole portion.
6. The golf club head according to claim 1, wherein, the distance
from the center of gravity is 29-32 mm.
7. The golf club head according to claim 1, wherein the height of
the center of gravity is 13-19 mm.
8. The golf club head according to claim 1, wherein the depth of
the center of gravity is 6-12 mm.
9. The golf club head according to claim 1, wherein the goose
distance is 6-12 mm.
10. The golf club head according to claim 4, wherein the specific
gravity of the circumferential edge portion is 7-8; and the
specific gravity of the inside portion is 1.3-5.
11. An iron type golf club comprising: a head; and a shaft; wherein
the head includes: a face portion having a face surface; a hosel
portion connected to a heel side of the face portion and defining a
through-hole; and a sole portion; wherein the shaft is inserted
into the through-hole; wherein a loft angle of the head is
15-25.degree.; wherein a distance from a center of gravity of the
head is 28-33 mm; and wherein height of the center of gravity is
12-21 mm.
12. The golf club according to claim 11, wherein depth of the
center of gravity from the face surface is 5-15 mm.
13. The golf club according to claim 11, wherein a goose distance
of the head is 4-15 mm.
14. The golf club according to claim 11, wherein the face portion
has a circumferential edge portion and an inside portion; wherein
the circumferential edge portion and the inside portion are made of
different materials; and wherein specific gravity of the material
of the inside portion is smaller than specific gravity of the
material of the circumferential edge portion.
15. The golf club according to claim 11, wherein a high specific
gravity member is provided in the sole portion; and wherein the
high specific gravity member is disposed near or behind a
longitudinal midpoint of the sole portion.
16. The golf club according to claim 11, wherein the distance from
the center of gravity of the head is 29-32 mm.
17. The golf club according to claim 11, wherein the height of the
center of gravity of the head is 13-19 mm.
18. The golf club according to claim 11, wherein the depth of the
center of gravity of the head is 6-12 mm.
19. The golf club according to claim 11, wherein the goose distance
of the head is 6-12 mm.
20. The golf club according to claim 14, wherein the specific
gravity of the circumferential edge portion is 7-8; and wherein the
specific gravity of the inside portion is 1.3-5.
Description
[0001] The present disclosure relates to the subject matter
contained in Japanese Patent Application No. 2002-1540 filed on
Jan. 8, 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 type golf club
head, and particularly relates to an iron type golf club head
applicable to a long iron having a small loft angle.
[0004] 2. Description of the Related Art
[0005] As known well, an iron type golf club head has a face
portion having a planar face surface, and a hosel portion connected
to the heel side of the face portion and provided with a shaft
insertion hole. A shaft is inserted into the shaft insertion hole
and fixedly attached thereto by a bonding agent. A distance
(distance in front view) between the center of gravity of the golf
club head and the extension of the shaft axis is called a distance
from the center of gravity.
[0006] A long iron is a club difficult for beginners to make a good
shot because it has a smaller loft angle and a longer shaft than
that of a short iron. Thus, the long iron is apt to be kept away
from the beginners. In order to make the long iron easy to hit a
shot, there has been an attempt that the golf club head of the long
iron is enlarged to increase its sweet area. However, when the golf
club head is enlarged, the distance from the center of gravity is
increased and the height of the center of gravity is also
increased. As a result, it is difficult for beginners or powerless
golfers to hit a ball high or the hit ball is apt to travel to the
right (in the case of right-handed golfers, the same thing will be
applied hereinafter) or slice heavily.
SUMMARY OF THE INVENTION
[0007] It is an object of the invention to provide a golf club
having an iron type golf club head small in loft angle, with which
club it is easy even for beginners or powerless golfers to hit a
ball high.
[0008] The iron type golf club head according to the invention has
a loft angle of 15-25.degree., and has a feature in that the
distance from the center of gravity is 28-33 mm, and the height of
the center of gravity is 12-21 mm.
[0009] In such an iron type golf club head, each of the distance
from the center of gravity and the height of the center of gravity
is smaller than that in a long iron head in the related art. Thus,
it becomes easy to hit a ball high even if a beginner uses a long
iron having the golf club head.
[0010] According to the invention, it is preferable that the depth
of the center of gravity from the face surface is 5-15 mm, and the
goose distance is 4-15 mm. In addition, it is desirable that the
circumferential edge portion of the face surface is made of a
material different in specific gravity from the material of the
area inside the circumferential edge portion, and the specific
gravity of the material of the inside area is smaller than that of
the material of the circumferential edge portion.
[0011] The definitions of the loft angle, the distance from the
center of gravity, the height of the center of gravity, the goose
distance and so on in the invention will be described with
reference to FIGS. 6 and 7.
[0012] First, a shaft is attached to a golf club head, and the
shaft is attached to a lie angle measuring instrument. The lie
angle measuring instrument chucks the shaft so that the shaft axis
always stays in a vertical plane. Then, the face surface is
adjusted to be square to a target. In addition, the sole surface of
the golf club head is adjusted so that toe-side and heel-side gaps
.alpha..sub.1 and .alpha..sub.2 are equal to each other with
respect to a reference plane (the level of a horizontal surface
plate). Incidentally, it is assumed that the sole surface between
the left end and the right end of corrugations (grooves long from
side to side in the face surface) is tangent to the reference
plane. The length of the corrugations is typically about 54-58 mm.
After that, the crossing angle of the reference plane and the shaft
axis (according with the axis of the hosel portion) is measured,
and this is regarded as the lie angle.
[0013] The distance between the center of gravity G and the shaft
axis in the front view of FIG. 6 (in which the face surface is
viewed from the square direction and projected on a plane
perpendicular to the reference plane) is the distance from the
center of gravity. In addition, the distance between the reference
plane and the center of gravity G is the height of the center of
gravity. The distance between a plane F.sub.1 closest to the toe
side and a plane F.sub.2 closest to the heel side of planes
perpendicular to the reference plane and tangent to a plane
parallel with the face square direction is the face portion
length.
[0014] As shown in FIG. 7, the distance between the face surface
and the center of gravity G is the depth of the center of gravity.
The crossing angle of the face surface and the shaft axis in the
side view of FIG. 7 is the loft angle. The distance between the
foremost end of the face surface and a plane F.sub.3 including the
foremost edge of the hosel portion (this plane F.sub.3 is
perpendicular to the face square direction) is the goose distance.
The distance between the face surface and a plane F.sub.4 including
the rearmost end (rearmost end in a direction perpendicular to the
face surface) of the golf club head is the maximum thickness of the
golf club head.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a front view of an iron type golf club head
according to an embodiment;
[0016] FIG. 2 is a side view of the iron type golf club head
according to the embodiment;
[0017] FIG. 3 is a sectional view taken on line III-III in FIG.
1;
[0018] FIG. 4 is a perspective view of the golf club head according
to the embodiment, viewed from its front;
[0019] FIG. 5 is a perspective view of the golf club head according
to the embodiment, viewed from its rear;
[0020] FIG. 6 is a view for explaining a method of measuring
characteristic values of a golf club head; and
[0021] FIG. 7 is a view for explaining the method of measuring
characteristic values of a golf club head.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Description will be made below on an embodiment with
reference to the drawings. FIG. 1 is a front view of an iron type
golf club head according to an embodiment. FIG. 2 is a side view of
the iron type golf club head according to the embodiment. FIG. 3 is
a sectional view taken on line III-III in FIG. 1. FIG. 4 is a
perspective view of the golf club head according to the embodiment,
viewed from its front. FIG. 5 is a perspective view of the golf
club head according to the embodiment, viewed from its rear.
[0023] This iron type golf club head 1 has a face portion 2 and a
hosel portion 3. The face portion 2 has a planar face surface 2f,
and the hosel portion 3 is connected to the heel side of the face
portion 2. A shaft insertion hole 4 is provided in the hosel
portion 3 so as to penetrate the hosel portion 3. The shaft
insertion hole 4 as a whole is disposed in front of a plane
including the face surface 2f so as to form a so-called goose neck,
as shown in FIG. 2.
[0024] Since the invention is suitably applied to a long iron, the
loft angle is set to be 15-25.degree.. Incidentally, it is
preferable that the club length of the long iron is 38-42 inches
(965-1,067 mm), particularly 38.5-41 inches (975-1,042 mm).
[0025] The distance from the center of gravity is set to be 28-33
mm, preferably 29-32 mm. When the distance from the center of
gravity is larger than this range, it becomes difficult
particularly for beginners to turn the head so that a hit ball is
apt to travel to the right or slice. On the contrary, when the
distance from the center of gravity is smaller than this range, it
becomes easy to turn the head excessively so that a missed shot
called a smothered ball or an excessive hook ball is apt to
appear.
[0026] The height of the center of gravity is set to be 12-21 mm.
The lower limit is preferably not smaller than 13 mm. It is
preferable that the upper limit is not larger than 21 mm,
especially not larger than 19mm, more especially not larger than 18
mm. When the height of the center of gravity of the golf club head
is made lower than that in the related art, it becomes easy to hit
a ball high. Incidentally, since the diameter of a golf ball is
about 43 mm, it is desirable that the height of the center of
gravity is lower than half the diameter (21.5 mm). Thus, the upper
limit is set at 21 mm. Technically, it is possible to make the
height of the center of gravity lower than 12 mm when the height of
the face portion 2 is reduced. In this case, however, the vertical
width of the sweet area is reduced, or there arises the feeling of
insecurity to the eyes of beginners (the feeling of insecurity that
it may be difficult to hit a ball on the face), or a missed shot
caused by the golf club head sneaking through the lower side of the
ball is produced in the rough easily. Accordingly, the lower limit
of the height of the center of gravity is set at 12 mm.
[0027] Incidentally, in order to reduce the height of the center of
gravity, a high specific gravity material 6 may be embedded in the
sole portion. The high specific gravity material preferably has a
specific gravity of 8 or higher. Specifically, tungsten, a tungsten
alloy, a copper alloy or the like is preferable. When the high
specific gravity material is disposed close to the rear (back
surface side) of the sole portion, the center of gravity is close
to the heel, and the depth of the center of gravity can be
increased, as will be described later.
[0028] The depth of the center of gravity is preferably 5-15 mm,
more preferably 6-12 mm. When the depth of the center of gravity is
made larger than that in the related art, it becomes easy to hit a
ball high. However, when the depth of the center of gravity is made
larger than 15 mm, the sole thickness increases correspondingly so
that it becomes difficult to hit a ball sinking in the rough or a
ball in a divot correctly. Thus, the upper limit of the depth of
the center of gravity is set at 15 mm.
[0029] Incidentally, in order to increase the depth of the center
of gravity, the high specific gravity material may be provided on
the back surface side of the sole bottom surface, or in the lower
portion of the back surface of the face portion.
[0030] It is preferable that the sole maximum thickness is 15-35
mm, especially 18-30 mm. When the sole maximum thickness is smaller
than 15 mm, the golf club head becomes easy to eat the ground at
the time of a fat shot (meaning a shot in which the golf club head
hits the ground short of a ball). On the contrary, when the sole
thickness is larger than 35 mm, it becomes difficult to hit a ball
sinking in the rough or a ball in a divot correctly.
[0031] It is preferable that the goose distance is 4-15 mm.
Particularly, it is preferable that the lower limit value of the
goose distance is not smaller than 6 mm, especially not smaller
than 8 mm, and the upper limit value thereof is not larger than 12
mm.
[0032] When the goose distance is made large to be not smaller than
4 mm, it becomes easy to turn the golf club head so that the
probability of a missed shot traveling to the right is reduced.
However, when the goose distance is larger than 15 mm, the
difference from the goose distance of the golf club head in the
related art is so significant that a missed shot is apt to be hit
or it takes much time unnecessarily for a user to adapt himself or
herself to the golf club head.
[0033] According to the invention, in order to increase the moment
of inertia around the axis of the center of gravity to thereby
expand the sweet area or in order to increase the depth of the
center of gravity, the circumferential edge portion of the face
portion may be made of a steel material such as stainless steel or
marageing steel while disposing a lower specific gravity material
in the area inside the circumferential edge portion. Incidentally,
the specific gravity of stainless steel or marageing steel is about
7-8. Examples of such lower specific gravity materials include
titanium, titanium alloys, aluminum alloys, magnesium alloys, and
fiber reinforced resin (for example, carbon fiber reinforced
resin), which are materials having a specific gravity of about
1.3-5.
[0034] Incidentally, in this embodiment, a crossing point P of the
axis of the shaft insertion hole 4 and the lower end surface of the
hosel portion 3 is located under an upper edge 2t of the face
portion 2 and above a lower edge 2b of the face portion, as
illustrated in FIG. 1.
[0035] In addition, in this embodiment, the axial length of the
shaft insertion hole 4 is preferably 25-35 mm, more preferably
27-32 mm. Further, in this embodiment, the lower end surface of the
hosel portion 3 is formed into a slope which is oblique with
respect to the axis of the shaft insertion hole 4 so that a part
closer to the lower end in the axial direction of the shaft
insertion hole 4 is closer to the face surface 2f.
[0036] More accurately, the point P is defined as a crossing point
of the axis of the shaft insertion hole 4 and a plane including the
lower end surface of the hosel portion 3. The plane including the
lower end surface of the hosel portion 3 (hereinafter referred to
as "hosel portion lower end surface" occasionally) is formed into a
slope in which a part closer to the lower end in the axial
direction of the shaft insertion hole 4 is closer to the face
surface 2f as described above. The hosel portion lower end surface
looks to the front lower portion of the face portion 2. In this
embodiment, the hosel portion lower end surface is bent to be
slightly concave in its section taken on a plane perpendicular to
the hosel portion lower end surface and including the axis of the
shaft insertion hole.
[0037] It is preferable that the angle with which a plane tangent
to the hosel portion end surface crosses the face surface 2f at the
point P where the plane including the lower end surface of the
hosel portion 3 crosses the axis of the shaft insertion hole 4 is
120-155.degree., especially 125-150.degree..
[0038] The tip of the shaft is inserted into the shaft insertion
hole 4 of the golf club head 1 and fixedly attached thereto by a
bonding agent. The tip of the shaft is ground to be flush with the
lower end surface of the hosel portion 3. When the shaft is hollow,
the shaft tip is sealed off with a filler. This filler is also
ground to be flush with the lower end surface of the hosel portion
3.
[0039] Since the shaft insertion hole 4 penetrates the hosel
portion 3 in such a manner, the axial length of the shaft insertion
hole 4 (the distance between the point P and the upper end surface
of the hosel portion 3) can be secured to be not smaller than 25 mm
even if the length of the hosel portion 3 as a whole is reduced.
Thus, the hosel portion 3 and the shaft can be fixedly attached to
each other sufficiently firmly. Then, by reducing the length of the
hosel portion 3 in such a manner, the upward protrusion length of
the hosel portion 3 is reduced so that the center of gravity of the
golf club head 1 is lowered. Thus, with the golf club provided with
the golf club head 1 whose center of gravity is low, it is easy
even for high handicapped golfers or low head speed golfers to hit
a ball high.
[0040] Incidentally, it is preferable that the hosel height is
40-57 mm, especially 40-53 mm. Since the hosel portion is
substantially cylindrical, the hosel height is defined as the
distance between the center point of the upper end surface of the
hosel portion and the reference plane.
[0041] In addition, when the shaft insertion hole 4 penetrates the
hosel portion 3, there is no metal material provided for closing
the lower portion of the shaft insertion hole, unlike the related
art. The golf club head is lightened by the weight of the metal
material. For example, when the weight by which the golf club head
is lightened is added to the sole of the golf club head, the golf
club head can be made lower in the position of the center of
gravity than that in the related art though the total weight of the
golf club head is equal to that in the related art.
[0042] The golf club head 1 has a shape in which the face surface
side of the lower end portion of the hosel portion 3 is cut
obliquely. Thus, it is difficult to hit a shank (hit a ball with a
socket).
[0043] Incidentally, according to the invention, it is preferable
to adopt a cavity back structure in which a concave portion 5 is
provided in the central portion of the back surface as shown in
FIG. 5. In addition, it is preferable to adopt a structure in which
the thickness is increased both on the heel side and on the toe
side. Such a shape is formed for expanding the sweet area of the
golf club head.
[0044] The golf club head 1 having a shape shown in FIGS. 1 to 5
was manufactured out of a titanium alloy having a specific gravity
of about 5 as its metal material, while a tungsten alloy having a
specific gravity of about 12 was embedded in the sole portion.
Table 1 shows the characteristic of this golf club head.
Incidentally, Table 1 also shows the measurement result of the
characteristic of a commercially available product having the same
loft angle.
[0045] Incidentally, the outer diameter of the hosel portion 3 was
made 13 mm, the inner diameter of the shaft insertion hole 4 was
made 9.4 mm, the axial length of the shaft insertion hole 4 was
made 30 mm, and the lie angle was made 60.degree..
1TABLE 1 loft angle distance from center height of center depth of
center sole maximum goose No. (degree) of gravity (mm) of gravity
(mm) of gravity (mm) thickness (mm) distance (mm) Example
23.degree. 31.8 17.5 6.8 28.4 10.2 Comp. 23.degree. 35.7 21.5 2.2
18.9 3.6 Example
[0046] A carbon shaft was attached to each of the golf club heads
so as to manufacture a golf club (long iron) having a club length
of 38.5 inches (978 mm). Thus, evaluation was made by trial shots.
As a result, a high handicapped golfer could not hit any shot but a
ground ball to the right using the golf club with the iron type
golf club head in Comparative Example. On the other hand, the high
handicapped golfer could hit a ball substantially straightly about
170 yards repeatedly using the golf club with the iron type golf
club head according to the invention.
[0047] As described above, according to the invention, a golf club
head is provided in which the center of gravity is low, and with
which it is easy even for beginners to hit a ball high, while there
is a little fear that a hit ball travels to the right or
slices.
* * * * *