U.S. patent application number 11/019815 was filed with the patent office on 2007-06-28 for golf club head with uniform response front face.
This patent application is currently assigned to Karsten Manufacturing Corporation. Invention is credited to Mustapha Hayouna, John C. Souza, David E. Wright.
Application Number | 20070149311 11/019815 |
Document ID | / |
Family ID | 38194591 |
Filed Date | 2007-06-28 |
United States Patent
Application |
20070149311 |
Kind Code |
A1 |
Wright; David E. ; et
al. |
June 28, 2007 |
Golf club head with uniform response front face
Abstract
A golf club head has a face insert the effective resiliency of
which varies across a striking surface on a front face of the club
head. The face insert, which is disposed in a cavity formed in the
club head, is supported from beneath by a substrate which is formed
of one or more materials to form a low resiliency region near a
central of the cavity and a high resiliency region near heel and
toe regions of the cavity. By varying the resiliency of the
substrate behind the face insert, the effective resiliency, which
is a composite of the face insert and the substrate, may be
manipulated so that the effective coefficient of restitution
between the club head and a golf ball may be made uniform across
the entire front face.
Inventors: |
Wright; David E.; (Glendale,
AZ) ; Hayouna; Mustapha; (Phoenix, AZ) ;
Souza; John C.; (Phoenix, AZ) |
Correspondence
Address: |
KARSTEN MANUFACTURING CORPORATION
LEGAL DEPARTMENT
2201 WEST DESERT COVE
PHOENIX
AZ
85029
US
|
Assignee: |
Karsten Manufacturing
Corporation
Phoenix
AZ
|
Family ID: |
38194591 |
Appl. No.: |
11/019815 |
Filed: |
December 21, 2004 |
Current U.S.
Class: |
473/329 ;
473/332; 473/340; 473/342 |
Current CPC
Class: |
A63B 53/0441 20200801;
A63B 60/54 20151001; A63B 53/0425 20200801; A63B 53/0487 20130101;
A63B 53/0416 20200801 |
Class at
Publication: |
473/329 ;
473/332; 473/342; 473/340 |
International
Class: |
A63B 53/00 20060101
A63B053/00 |
Claims
1. A golf club head comprising: a body having a front face, a rear
surface and a cavity extending from the front face toward the rear
surface, said cavity having a bottom surface; a first face insert
formed of a first material, said first face insert having a front
surface and a back surface, said first face insert disposed within
the cavity with the back surface of said first face insert adjacent
the bottom surface of the cavity; a second face insert formed of a
second material, said second face insert having a front surface and
a back surface, said second face insert disposed within the cavity
with the back surface of said second face insert adjacent the
bottom surface of the cavity; and a third face insert disposed
within the cavity atop said first face insert and said second face
insert, said third face insert including a plurality of elongate
rod elements each having a first end, a second end and a side
surface, said plurality of elongate rod elements arranged in a
parallel closely packed array such that the side surface of each of
said plurality of elongate rod elements is in contact with the side
surface of an adjacent one of said plurality of elongate rod
elements, the first ends of said plurality of elongate rod elements
abutting the front surface of one of said first face insert and
said second face insert, and said second ends of said plurality of
elongate rod elements exposed to form a striking surface on the
front face of the body.
2. The golf club head of claim 1, wherein the second material
forming said second face insert has a lower resiliency than the
first material forming said first face insert.
3. The golf club head of claim 2, wherein said second material is
an elastomer.
4. The golf club head of claim 3, wherein said first material is a
metal alloy.
5. The golf club head of claim 1, wherein said cavity comprises a
central region, a heel region and a toe region, and wherein said
first face insert is disposed in one of said heel and toe regions
and said second face insert is disposed in said central region.
6. The golf club head of claim 5, wherein the second material
forming said second face insert has a lower resiliency than the
first material forming said first face insert such that said front
face proximal said central region will exhibit the same effective
coefficient of restitution as said front face proximal said one of
said heel and toe regions.
7. The golf club head of claim 1, wherein said cavity comprises a
central region, a heel region and a toe region, and wherein said
first insert is disposed in said heel region of said cavity and
said second face insert is disposed in said central region of said
cavity.
8. The golf club head of claim 7, further comprising a fourth face
insert disposed in said toe region of said cavity and formed of the
first material.
9. The golf club head of claim 8, wherein the second material
forming said second face insert has a lower resiliency than the
first material forming said first face insert and said fourth face
insert, such that said front face proximal said central region will
exhibit the same effective coefficient of restitution as said front
face proximal said heel region and said toe region.
10. A golf club head comprising: a body having a rear surface, a
front face, a heel end, a toe end and a cavity extending from the
front face toward the rear surface, said cavity having a central
region and a bottom surface; a face insert having a front surface
and a back surface, said front surface including a striking surface
on the front face of said body; and a substrate disposed in said
cavity sandwiched between the back surface of said face insert and
the bottom surface of said cavity, said substrate having a
resiliency that varies from a high resiliency value proximal the
toe end of said body to a low resiliency value proximal the central
region of said cavity such that said golf club head exhibits a
substantially uniform effective coefficient of restitution across
the face insert when striking a golf ball.
11. The golf club head of claim 10, wherein said face insert
comprises a plurality of elongate rod elements each having a first
end, a second end and a side surface, and said plurality of
elongate rod elements arranged in a parallel closely packed array
such that the side surface of each of said plurality of elongate
rod elements is in contact with a side surface of an adjacent one
of said plurality of elongate rod elements.
12. The golf club head of claim 10, wherein said substrate
comprises a first insert and a second insert, said first insert
being formed of a first material having a first resiliency value,
said second insert being formed of a second material having a
second resiliency value less than said first resiliency value, and
said second insert being located proximal the central region of
said cavity.
13. The golf club head of claim 11, wherein said substrate
comprises a first insert and a second insert, said first insert
being formed of a first material having a first resiliency value,
said second insert being formed of a second material having a
second resiliency value less than said first resiliency value, and
said second insert being located proximal the central region of
said cavity.
14. The golf club head of claim 13, wherein said first material is
a metal alloy and said second material is an elastomer.
15. The golf club head of claim 10, wherein said substrate also has
said high resiliency value proximal the heel end of said body.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to golf equipment and, in
particular, to golf club heads.
[0002] As is well known to golf manufacturers and many golfers, the
"sweet spot" of a golf club head is the point on the front face at
which a line drawn normal to the front face passes through the
center of gravity of the golf club head. If a golfer swings a golf
club so that the club head impacts the golf ball at the sweet spot,
few if any harmonic vibrations are excited within the golf club
head and shaft system. Consequently, the maximum amount of energy
from the golfer's swing is available for momentum transfer to the
golf ball. Conversely, if the golfer swings the golf club so that
it impacts the golf ball away from the sweet spot, the impact
frequently excites various torsional and bending oscillations. Such
a mis-hit has two deleterious consequences. The harmonic
oscillations are felt as unpleasant vibrations transmitted to the
golfer's hands and the energy lost through the harmonic
oscillations is not available for momentum transfer to the golf
ball thus resulting in a shorter distance of travel for the golf
ball for the same swing speed. This effect is compounded by the
fact that in many cases the sweet spot on the front face is at or
near the point of the front face which has the highest compliance
and therefore, the highest effective coefficient of restitution.
Thus, a golf ball hit at the sweet spot will travel substantially
further than a golf ball hit at a point on the front face away from
the sweet spot. Accordingly, it would be advantageous to provide a
golf club head having a lower resilience toward the center of the
club head and a higher resiliency toward heel and toe ends of the
club head so that the energy transferred to the golf ball would be
uniform across the front face irrespective of where the impact
occurs.
[0003] U.S. Pat. No. 5,807,190 to Krumme, et al. discloses a club
head in which the face insert is composed of many small rods
arranged in a closely packed array. According to the Krumme patent,
use of individual rod segments to form the front face allows the
properties of the front face to vary in any pattern over the impact
area, simply by varying the materials out of which the individual
rods are made. Use of multiple materials within the array of rods
could render a front face having the desired distribution of
resiliency. Such use of multiple materials would, however, render
the club hard non-conforming, for Rule 5(b) of Appendix II of the
United States Golf Association requires that the whole of the
impact area of a club head be of the same material. Accordingly,
what is needed is a golf club head in which the resiliency of the
face may be varied across the front face without varying the rod
material.
SUMMARY OF THE INVENTION
[0004] The present invention comprises a golf club head having a
face insert the effective resiliency of which varies across a
striking surface on a front face of the club head body. According
to an illustrative embodiment, the club head body has a cavity for
receiving a face insert. The face insert, which is disposed in the
cavity, is supported from beneath by a substrate sandwiched between
a back surface of the face insert and a bottom surface of the
cavity. The substrate is formed of one or more materials to provide
the substrate with low resiliency near a central region of the
cavity and higher resiliency near either a heel region or a toe
region of the cavity. By varying the substrate, the effective
resiliency, which is a composite of the face insert and substrate,
may be manipulated so that the effective coefficient of restitution
between the club head and a golf ball may be made uniform across
the entire front face.
DESCRIPTION OF THE DRAWINGS
[0005] The present invention will be better understood from a
reading of the following detailed description, taken in conjunction
with the accompanying drawings figures in which like references
designate like elements and, in which:
[0006] FIG. 1 is a front perspective view of a golf club head
incorporating features of the present invention;
[0007] FIG. 2 is a cross-sectional view of the golf club head of
FIG. 1 taken along line 2-2; and
[0008] FIG. 3 is a cross-sectional view of an alternative
embodiment of a golf club head incorporating features of the
present invention.
DESCRIPTION OF THE INVENTION
[0009] The drawing figures are intended to illustrate the general
manner of construction and are not necessarily to scale. In the
detailed description and in the drawing figures, specific
illustrative examples are shown and herein described in detail. It
should be understood, however, that the drawing figures and the
detailed description are not intended to limit the invention to the
particular form disclosed but are merely illustrative and intended
to teach one of ordinary skill how to make and/or use the invention
claimed herein and for setting forth the best mode for carrying out
the invention.
[0010] With reference to FIGS. 1 and 2, a golf club head 10,
preferably a golf putter head, comprises a club head body 12
attached to a golf club shaft 14. Typically, the club head body 12
is made of a suitable metal such as steel formed by an investment
casting process, however, metal materials such as titanium,
aluminum, tungsten, brass, bronze and beryllium copper may be used
to form club head body 12. Those skilled in the art will recognize
also that the club head body 12 may be made of other metallic or
non-metallic materials without departing from the spirit and scope
of the present invention. Club head body 12 has a front face 16, a
rear surface 18, a heel end 20 and a toe end 22, as well as a top
rail 24 and sole 26.
[0011] As shown most clearly in FIG. 2, club head body 12 is formed
with a cavity 28 that extends from the front face 16 toward the
rear surface 18 and is defined by side wall 30 and bottom wall or
surface 32. A striking surface 34 on the front face 16 of club head
body 12 is provided by a front face insert 36 supported by a
substrate 38 disposed in cavity 28. Substrate 38 is preferably
composed of additional face inserts 40, 42 and 44. Face insert 36
preferably comprises a plurality of individual rod elements 46. Rod
elements 46 are all of substantially identical geometry except for
their individual lengths. Accordingly, the individual rod elements
46 are not separately described herein in detail. Rod elements 46
are packed together in an array such that each side surface 48 is
in contact with the side surface of an adjacent rod element 46.
Face insert 36 is positioned in cavity 28 such that the bottom ends
50 of the rod elements 46 are supported by the upper surfaces 52,
54 and 56 of face inserts 40, 42 and 44. The exposed ends 58 of rod
elements 46 are finished flat to form the striking surface 34 on
the front face 16. Face insert 36 may be formed of individual rod
elements of circular cross-section (not shown), but preferably
comprises a plurality of metal alloy rod elements 46 of hexagonal
cross-section (as seen in FIG. 1) arranged in a close-packed array
surrounded by an epoxy binder 60 that holds the rod elements 46 in
place.
[0012] Face insert 40, which is positioned in a central region 62
of cavity 28 is preferably made from an elastomer such as
polyurethane having a resiliency of between 0.5 and 0.85. Face
inserts 42 and 44 may be made of a metal alloy, ceramic or
elastomer having a resiliency greater than that of face insert 40.
The material choices for face inserts 40, 42 and 44 will vary from
club head to club head depending on the location of the vibrational
nodes and anti-nodes of the golf club head.
[0013] Where a principal node of the club head is located in the
central region 62 of cavity 28, little energy is lost due to the
excitation of harmonic vibrations within the club head 10.
Accordingly, a golf ball will travel a greater distance for a given
club head speed. Conversely, if a golf ball is struck in a heel
region 64 of cavity 28 proximal face insert 42, energy will be lost
due to the excitation of harmonic vibrations in club 10 and the
ball will not travel as far. Similarly, if a golf ball is struck in
a toe region 66 of cavity 28 proximal face insert 44, energy will
be lost due to the excitation of harmonic vibrations in club head
10. The energy lost in a "toe hit" versus a "heel hit" may or may
not be the same. Therefore, in order to compensate separately for a
"toe hit" or "heel hit", the material chosen for face inserts 42
and 44 may be of different resiliencies so as to dissipate
different amounts of energy.
[0014] The effective coefficient of restitution, as used herein, is
the ratio of the velocity of a golf ball struck by the golf club
head at various locations on the front face as compared to the
velocity of the golf ball in a perfectly elastic collision. The
apparent coefficient of restitution C for a golf club of mass M1
travelling at a velocity V1 and striking a stationary golf ball of
mass M2 may be described by the following equation:
C=(V.sub.2b-V.sub.2c)/(V.sub.1c-V.sub.1b) Where V.sub.1c is the the
club head velocity before impact, V.sub.1b is the ball velocity
before impact, V.sub.2c is the club head velocity after impact, and
V.sub.2b is the ball velocity after impact.
[0015] The effective coefficient of restitution will be a function
of not only the composite resiliency of face insert 36 and any one
of face inserts 40, 42 and 44 but also the energy lost due to the
aforementioned excitation of vibrations within the club head. Since
the material of face insert 36 must be the same across the entirety
of striking surface 34, and since the losses introduced as a result
of exciting harmonic vibrations within golf club head 10 are
difficult to control, the effective coefficient of restitution can
be made uniform across the striking surface 34 most effectively by
reducing the resiliency of face insert 40 relative to face inserts
42 and 44 so that the sum of the energy lost due to the resiliency
of the face inserts 42, 44, 46 plus the energy lost due to the
excitation of harmonic vibrations is equal across the front face 16
of the body 12. Although the resiliency of face insert 36 has some
effect on the overall resiliency, the overall resiliency of
striking surface 34 is dominated by the resiliency of substrate 38.
Therefore, the overall resiliency of striking surface 34 can be
manipulated by altering the resiliency of substrate 38
notwithstanding the presence of face insert 36. The result is that,
for a given club head velocity, the golf club head will impart the
same initial velocity to a golf ball irrespective of where on the
front face the golf ball is hit.
[0016] With reference to FIG. 3, an alternative embodiment of a
golf club head incorporating features of the present invention
comprises a club head body 312 having a front face 316, a rear
surface 318, a heel end 320 and a toe end 322. A cavity 328 with a
side wall 330 extends from the front face 316 toward the rear
surface 318 and terminates in a bottom wall 329. As with the
illustrative embodiment of FIG. 2, a face insert 336 is supported
by a substrate 338 composed of face inserts 340, 342 and 344. In
order to provide a smoother transition from the high resiliency
heel and toe regions 341, 343 proximal face inserts 342 and 344 to
the low resiliency region 345 proximal face insert 340, transition
regions 346 and 348 are provided in which face insert 340 is
partially supported by face inserts 342 and 344, which causes the
effective coefficient of restitution in transition regions 346 and
348 to be a composite that includes the resiliency of face insert
340 as well as the resiliency of face insert 342 and face insert
344.
[0017] Although certain illustrative embodiments and methods have
been disclosed herein, it will be apparent from the foregoing
disclosure to those skilled in the art that variations and
modifications of such embodiments and methods may be made without
departing from the spirit and scope of the invention. For example,
first face insert may be a solid insert or a veneer rather than a
plurality of rod elements. Accordingly, it is intended that the
invention should be limited only to extent required by the appended
claims and the rules and principals of applicable law.
* * * * *