U.S. patent application number 17/303093 was filed with the patent office on 2021-11-25 for golf club strikeface with off-axis directional grain structure.
The applicant listed for this patent is KARSTEN MANUFACTURING CORPORATION. Invention is credited to Matthew W. Simone.
Application Number | 20210362012 17/303093 |
Document ID | / |
Family ID | 1000005768330 |
Filed Date | 2021-11-25 |
United States Patent
Application |
20210362012 |
Kind Code |
A1 |
Simone; Matthew W. |
November 25, 2021 |
GOLF CLUB STRIKEFACE WITH OFF-AXIS DIRECTIONAL GRAIN STRUCTURE
Abstract
The golf club head described herein has a metal alloy strikeface
formed from a faceplate having an off-axis directional grain
structure. The directional grain structure can be formed of
elongated grains. The faceplate can have a horizontal reference
axis, extending in a heel to toe direction. The elongated grains
can be angled in a longitudinal direction that is offset from the
horizontal reference axis by an angle of between 5 and 85 degrees.
The directional grain structure can be oriented from a low-heel
region to a high-toe region of the strikeface. In some embodiments,
the golf club head can have a relatively uniform characteristic
time (CT) across the strikeface. Specifically, a CT differential
across the strikeface can be between 0 and 7 .mu.s.
Inventors: |
Simone; Matthew W.;
(Phoenix, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KARSTEN MANUFACTURING CORPORATION |
Phoenix |
AZ |
US |
|
|
Family ID: |
1000005768330 |
Appl. No.: |
17/303093 |
Filed: |
May 19, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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63029459 |
May 23, 2020 |
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63198378 |
Oct 14, 2020 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A63B 53/08 20130101;
A63B 53/0408 20200801; A63B 53/0462 20200801 |
International
Class: |
A63B 53/08 20060101
A63B053/08; A63B 53/04 20060101 A63B053/04 |
Claims
1. A golf club head comprising: a club head body comprising, a
heel, a toe, a crown, a sole, a rear, and a strikeface positioned
adjacent the sole and the crown and opposite the rear; wherein: the
club head further comprises a loft plane tangent to the strikeface;
the strikeface comprises: a geometric center; a horizontal
reference axis extending from the toe to the heel within the loft
plane and through the geometric center of the strikeface; a
faceplate; the faceplate comprises a directional grain structure
formed of elongated grains oriented on average in a longitudinal L
direction; the longitudinal L direction is angularly offset from
the horizontal reference axis by an offset angle .theta. of between
5 and 85 degrees; and the offset angle .theta. is measured
counterclockwise from the horizontal reference axis.
2. The golf club head of claim 1, wherein the offset angle .theta.
is selected from the group consisting of: between 20 and 70
degrees, between 35 and 55 degrees, between 5 and 45 degrees, and
between 45 and 85 degrees.
3. The golf club head of claim 1, wherein the offset angle .theta.
is selected from the group consisting of: 5 degrees, 10 degrees, 15
degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40
degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65
degrees, 70 degrees, 75 degrees, 80 degrees, and 85 degrees.
4. The golf club head of claim 1, wherein the faceplate comprises a
titanium alloy material selected from the group consisting of:
Ti-6A1-4V (or Ti 6-4), Ti-7S+(or Ti-7S, T-7S, or ST721), Ti-9S (or
T-9S), Ti-9S+, HST-180, FS2S, Super-TiX 51AF, Super-TiX 51 Premium,
Ti-662, Ti-8-1-1, Ti-65K, Ti-6246, and IMI 550.
5. The golf club head of claim 1, wherein the faceplate comprises a
steel material selected from the group consisting of: C300 steel,
C350 steel, 455 steel, 431 steel, 475 steel, 565 steel, 17-4
stainless steel, maraging steel, Ni--Co--Cr steel alloy, AerMet 310
steel, and AerMet 340 steel.
6. The golf club head of claim 1, wherein the elongated grains are
oriented within 0 to 30 degrees of each other.
7. The golf club head of claim 1, wherein: the strikeface further
comprises an inner surface and an outer surface; the strikeface
further comprises a thickness measured between the inner surface
and the outer surface, perpendicular to the loft plane; and the
thickness varies across the strikeface.
8. The golf club head of claim 7, wherein: the strikeface further
comprises a central region, a transition region surrounding the
central region, and a peripheral region surrounding the transition
region; the thickness of the central region is greater than the
thickness of the peripheral region; and the thickness of the
transition region varies.
9. The golf club head of claim 7, wherein a minimum thickness of
the strikeface is between 1.5 mm and 0.4 mm.
10. The golf club head of claim 7, wherein the central region
comprises an elliptical or egg-shaped boundary.
11. The golf club head of claim 1, wherein the characteristic time
(CT) of the golf club head is lower than a similar golf club head
lacking a directional grain structure oriented at the offset angle
.theta. of between 5 and 85 degrees.
12. The golf club head of claim 1, wherein: the golf club head
comprises a characteristic time (CT) differential of between 0 and
7 .mu.s, and the characteristic time differential is measured as
the difference between a maximum characteristic time (CT) of the
strikeface and a minimum characteristic time (CT) of the
strikeface.
13. The golf club head of claim 1, wherein: the faceplate further
comprises a transverse T direction oriented perpendicular to the
longitudinal L direction; the faceplate comprises a longitudinal
modulus of elasticity measured in the longitudinal L direction and
a transverse modulus of elasticity measured in the transverse T
direction; and the longitudinal modulus of elasticity is lower than
the transverse modulus of elasticity.
14. The golf club head of claim 13, wherein: the longitudinal
modulus of elasticity ranges between 108 GPa and 118 GPa (15.66
Mpsi and 17.11 Mpsi); and the transverse modulus of elasticity
ranges between range between 118 GPa and 146 GPa (17.11 Mpsi-21.17
Mpsi).
15. The golf club head of claim 1, wherein: the offset angle
.theta. is approximately 45 degrees; and the modulus of elasticity
taken along the horizontal reference axis is between 116 GPa and
130 GPa.
16. A golf club head comprising: a club head body comprising, a
heel, a toe, a crown, a sole, a rear, and a strikeface positioned
adjacent the sole and the crown and opposite the rear; wherein: the
club head further comprises a loft plane tangent to the strikeface;
the strikeface comprises: a geometric center; a vertical reference
axis extending from the crown to the sole within the loft plane and
through the geometric center of the strikeface; a horizontal
reference axis extending from the toe to the heel within the loft
plane and through the geometric center of the strikeface; a
high-toe region defined above the horizontal reference axis and on
a toe side of the vertical reference axis; a high-heel region
defined above the horizontal reference axis and on a heel side of
the vertical reference axis; a low-toe region defined below the
horizontal reference axis and on a toe side of the vertical
reference axis; a low-heel region defined below the horizontal
reference axis and on a heel side of the vertical reference axis;
and a metal material with a directional grain structure that is
oriented in a direction from the low-heel region to the high-toe
region.
17. The golf club head of claim 16, wherein: the strikeface
comprises a faceplate; the faceplate further comprises a transverse
T direction oriented perpendicular to the longitudinal L direction;
the faceplate comprises a longitudinal modulus of elasticity
measured in the longitudinal L direction and a transverse modulus
of elasticity measured in the transverse T direction; and the
longitudinal modulus of elasticity is lower than the transverse
modulus of elasticity.
18. The golf club head of claim 16, wherein: the golf club head
comprises a characteristic time (CT) differential of between 0 and
7 .mu.s, and the characteristic time differential is measured as
the difference between a maximum characteristic time (CT) of the
strikeface and a minimum characteristic time (CT) of the
strikeface.
19. The golf club head of claim 16, wherein the angled orientation
of the directional grain structure causes a reduction in the
characteristic time (CT) of the high-toe region, compared to a club
head comprising a strikeface having a horizontal-oriented
directional grain structure.
20. The golf club head of claim 16, wherein the strikeface
comprises a titanium alloy material selected from the group
consisting of: Ti-6A1-4V (or Ti 6-4), Ti-7S+(or Ti-7S, T-7S, or
ST721), Ti-9S (or T-9S), Ti-9S+, HST-180, FS2S, Super-TiX 51AF,
Super-TiX 51 Premium, Ti-662, Ti-8-1-1, Ti-65K, Ti-6246, and IMI
550.
Description
FIELD
[0001] The present disclosure relates generally to golf equipment,
and more particularly, to a golf club head having an anisotropic
faceplate with an off-axis grain structure angled from low-toe to
high-heel.
BACKGROUND
[0002] The flexibility of a strikeface (colloquially known as how
"hot" the face is) correlates to the speed imparted to a golf ball
upon impact. There are two methods for measuring the flexibility of
a strikeface: characteristic time (CT) and coefficient of
restitution (COR). Characteristic time (CT) is the amount of time,
measured in microseconds, that the strikeface of the club head
remains in contact with a metal ball used in a testing apparatus.
CT measures the spring-like reaction of the strikeface. Coefficient
of restitution (COR) is the ratio of final relative velocity to
initial relative velocity between two objects after they collide.
In golf, COR is tested by firing a golf ball at a stationary
faceplate or club head strikeface. COR is measured as the ratio of
the final relative velocity of the golf ball after collision/impact
with the club head strikeface to the initial relative velocity of
the golf ball prior to collision/impact. The COR indicates how much
energy is transferred from the golf club to the golf ball at
impact. In other words, COR shows the efficiency of the golf club
head. Both CT and COR relate to the strikeface material properties,
such as the modulus of elasticity.
[0003] The spring effect and dynamic properties of club heads with
loft angles of 35 degrees or less is governed by the Equipment
Rules Part 2, Section 4c, as administered by the R&A Rules,
Ltd. (The R&A) and the United States Golf Association (USGA).
Measurement of characteristic time (CT) is employed by the R&A
and the USGA to determine conformance of a club head to the
equipment rules. The characteristic time (CT) test was developed as
a simpler method of testing the flexibility of a strikeface,
compared to the more realistic but more time-intensive and
equipment-intensive coefficient of restitution (COR) test.
[0004] To be conforming to the CT requirement, a golf club head
(which includes the club face) must not have the effect of a spring
which exceeds the limit set forth in the Pendulum Test Protocol
(also called the Protocol for Measuring the Flexibility of a Golf
Clubhead) on file with the R&A and the USGA (TPX3004 Rev. 2.0,
Apr. 9, 2019) (available at
https://www.usga.org/content/dam/usga/pdf/2019/equipment-standards/TPX300-
4%20Protocol%20for%20Measuring%20the%20Flexibility%20of%20a%20Golf%20Clubh-
ead.pdf). In particular, for most wood-type golf club heads, a club
head will be non-conforming if the CT value at the center of the
face is greater than 239 microseconds (.mu.s), plus an 18 .mu.s
tolerance. Furthermore, the club head will be non-conforming if the
CT value exceeds 239 .mu.s plus an 18 .mu.s tolerance anywhere
within the impact area, or exceeds 257 .mu.s plus an 18 .mu.s
tolerance outside the impact area.
[0005] Due to the high strength and high flexibility of the metal
materials used to make faceplates in current golf club heads, some
equipment manufacturers are producing club heads that achieve close
to the maximum CT limit. As described above, a club head having a
CT above 239 .mu.s (+/-18 .mu.s) in any region within the impact
area will be non-conforming. Therefore, if a region of the
strikeface away from the geometric center has a higher CT value
than the geometric center, the strikeface will be non-conforming
while also failing to provide the maximum spring like rebound for
the golf ball at the strikeface geometric center. The herein
described strikeface design comprises a more uniform CT that not
only conforms to the R&A and USGA regulations, but also
provides golfers with a uniform and maximum efficiency response
across the face.
[0006] Traditionally, the CT of a strikeface or faceplate was
altered by changing the overall thickness of the faceplate. An
overall thicker faceplate bends less, resulting in a lower CT. An
overall thinner faceplate bends more, resulting in a higher CT. The
anisotropic faceplate described herein lowers the CT value of the
high-toe region without thickening the strikeface. In addition to
correlating to the thickness of the strikeface, the CT value also
correlates to the modulus of elasticity of the strikeface material.
The CT value of the strikeface increases as the modulus of
elasticity of the strikeface is decreased. Similarly, the CT value
decreases as the modulus of elasticity is increased. The club head
described herein employs a strikeface with an off-axis directional
grain structure, which achieves a lower modulus of elasticity than
similar strikefaces lacking the off-axis directional grain
structure. This lower overall modulus of elasticity reduces the CT
value of the high-toe region of the strikeface without
necessitating an increase in the overall thickness of the
strikeface.
[0007] Due to the mechanics of a golf swing, a majority of hits
happen within the high-toe region of the strikeface. The prior art
touts that aligning a faceplate's longitudinal grain structure
(roll direction) in a high-toe to low-heel (HTLH) direction
allegedly increases the strength and durability of the strikeface
in the high-impact regions compared to aligning the faceplate's
longitudinal grain structure (roll direction) in a low-toe to
high-heel (LTHH) direction. However, as the examples below show,
HTLH and LTHH grain structure orientations exhibit similar
durability. Furthermore, advances in material strength properties
have reduced the need for durability increases. Therefore, although
sufficient durability is needed, the strikeface CT value carries
greater importance for the instant disclosure.
[0008] As stated above, there is now a need to focus on creating a
uniform CT across the strikeface so that the overall CT value can
be raised. Raising the CT value increases shot ball speed. There is
also a need in the art for a means of controlling the CT value so
that the golf club head remains within the USGA and R&A
conformance requirements.
[0009] Most golf club heads have metal faceplates intended for
striking golf balls. Each metal faceplate is cut from a rolled
sheet of metal, which has a directional grain structure aligned
with the rolling direction. The metal has different properties
along the rolling direction (longitudinal) compared to
perpendicular to the rolling direction (transverse). Typically, a
faceplate is formed so that the longitudinal grain structure
direction (roll direction) of the metal is aligned horizontally in
the faceplate. However, some faceplates are cut so that the
longitudinal direction of the metal is angled from a high-toe
region to a low-heel region (HTLH). Said high-toe to low-heel
(HTLH) angulation of the rolled metal allegedly result in an
anisotropic faceplate having a greater strength and durability in
the high-toe region than a similar club without the angulation of
the rolled metal. The prior art teaches HTLH angulation, in part,
because players typically hit balls from the low-heel to the
high-toe region on the faceplate. The prior art alleges that
angulation of the metal grain structure increases the high-toe and
low-heel strength and decreases the modulus of elasticity in these
regions.
[0010] To manufacture a golf club head, a faceplate component is
welded to a body component. The faceplate is created by running a
unidirectional metal sheet (typically a titanium alloy) through a
series of rollers to achieve a desired faceplate thickness. Once
run through the rollers, the metal sheet has a directionality along
the roller direction. Next, unformed faceplates are cut out of the
metal sheet with stamps, punches, or lasers. Then, the unformed
faceplates are individually run through a press wherein a set of
press dies forms the desired faceplate bulge and thickness.
Alternately, the unformed faceplates can be milled to the desired
thickness. The faceplate is then laser welded to the body component
of the golf club head.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows a perspective view of a golf club head,
according to one embodiment.
[0012] FIG. 2 shows a heel-side view of the golf club head of FIG.
1.
[0013] FIG. 3 shows a front view of the golf club head of FIG.
1.
[0014] FIG. 4 shows a cross-sectional diagram of material grain
structure and its formation during a rolling process.
[0015] FIG. 5 shows a second front view of the golf club head of
FIG. 1.
[0016] FIG. 6 shows a front view of a golf club head, according to
an embodiment.
[0017] FIG. 7 shows a cross-sectional rear view of the golf club
head of FIG. 1, taken along line VII-VII of FIG. 2.
[0018] FIG. 8 shows a cross-sectional view of the faceplate of the
golf club head of FIG. 7, taken along line VIII-VIII of FIG. 7.
DEFINITIONS
[0019] Described herein, the term "anisotropy" means a property of
a substance having different physical properties in different axial
directions. For example, a component that exhibits different moduli
of elasticity or different strength values when measured along
different axial directions.
[0020] Described herein, the term "characteristic time" (CT) means
the amount of time, measured in microseconds, that the strikeface
of a club head remains in contact with a metal ball used in a
testing apparatus.
[0021] As described above, the coefficient of restitution (COR) is
the ratio of final relative velocity to initial relative velocity
between two objects after they collide. COR is measured as the
ratio of the final relative velocity of the golf ball after
collision/impact with the club head strikeface to the initial
relative velocity of the golf ball prior to collision/impact.
DESCRIPTION
[0022] Described herein below is a club head with an anisotropic
faceplate, having an intermediate modulus of elasticity value that
contributes to more uniform characteristic time (CT) across the
faceplate.
[0023] The present invention uses low-toe to high-heel (LTHH)
angulation of the metal grain structure to increase the high-toe
and low-heel modulus of elasticity. The orientation of the material
grain structure is determined by the rolling direction of the base
material during manufacturing. The present invention orients the
directional grain structure (also rolling direction) from low-toe
to high-heel (LTHH) to control the modulus value in the high-toe
and low-heel regions. Due to the geometry of a golf club head, the
high-toe region typically experiences high characteristic time
(CT). Increasing the elasticity in the high-toe and low-heel
regions, makes these regions less flexible and hot. In this way,
the present invention's orientation of the metal grain structure
(roll direction) achieves a faceplate having a more balanced or
uniform CT across the faceplate. Presented below is a golf club
head comprising a faceplate having a metal grain structure that
extends from low-toe to high-heel (LTHH).
[0024] Referring to FIGS. 1-3, the golf club head 50 described
herein can be a wood-type golf club head, such as a driver, a
fairway wood, a hybrid, or any other wood-type club head. The golf
club head 50 comprises a heel 56, a toe 60 opposite the heel 56, a
hosel 58, a crown 52, a sole 54 opposite the crown 52, a rear 62,
and a strikeface 64 opposite the rear 62. The strikeface 64 is
positioned adjacent and between the sole 54 and the crown 52. The
strikeface 64 is configured to withstand impact with a golf ball
during a golf swing. The golf club head 50 can comprise a body 98
and a faceplate 68. The faceplate 68 forms at least a portion of
the strikeface 64.
[0025] Referring to FIG. 3, the strikeface 64 of the club head
defines a geometric center 66. In some embodiments, the geometric
center 66 can be located at the geometric centerpoint of a
strikeface perimeter, and at a midpoint of a height 92 of the
strikeface 64. In the same or other examples, the geometric center
66 also can be centered with respect to an engineered impact zone,
which can be defined by a region of grooves on the strikeface 64.
As another approach, the geometric center 66 of the strikeface 64
can be located in accordance with the definition of a golf
governing body such as the United States Golf Association (USGA).
For example, the geometric center 66 of the strikeface 64 can be
determined in accordance with Section 6.1 of the USGA's Protocol
for Measuring the Flexibility of a Golf Clubhead (TPX3004 Rev. 2.0,
Apr. 9, 2019) (available at
https://www.usga.org/content/dam/usga/pdf/2019/equipment-standards/TPX300-
4%20Protocol%20for%20Measuring%20the%20Flexibility%20of%20a%20Golf%20Clubh-
ead.pdf).
[0026] Referring to FIGS. 2 and 3, the club head 50 further defines
a loft plane 12 tangent to the geometric center 66 of the
strikeface 64. The face height 92 can be measured parallel to the
loft plane 12 between a top end of the strikeface perimeter near
the crown 52 and a bottom end of the strikeface perimeter near the
sole 54. In these embodiments, the strikeface perimeter can be
located along the outer edge of the strikeface 64 where the
curvature deviates from the bulge and/or roll of the strikeface 64.
A loft angle 14 can be measured as the angulation of the loft plane
12 from a ground plane 10.
[0027] Referring to FIG. 3, the strikeface geometric center 66
further defines a coordinate system having an origin located at the
strikeface geometric center 66, the coordinate system having a
horizontal reference axis 16 and a vertical reference axis 18. The
vertical reference axis 18 extends within the loft plane 12,
through the strikeface geometric center 66 in a direction from the
crown 52 to the sole 54. The horizontal reference axis 16 extends
within the loft plane 12, through the strikeface geometric center
66 in a direction from the heel 56 to the toe 60 of the club head
50.
[0028] The strikeface 64 further comprises a high-toe region 70, a
high-heel region 72, a low-toe region 74, and a low-heel region 76.
The high-toe region 70 is defined above the horizontal reference
axis 16 and on the toe side of the vertical reference axis 18 (the
toe side is closer to the toe 60 than the heel 56). The high-heel
region 72 is defined above the horizontal reference axis 16 and on
the heel side of the vertical reference axis 18 (the heel side is
closer to the heel 56 than the toe 60). The low-toe region 74 is
defined below the horizontal reference axis 16 and on the toe side
of the vertical reference axis 18. The low-heel region 76 is
defined below the horizontal reference axis 16 and on the heel side
of the vertical reference axis 18.
[0029] The golf club head body 98 can form the crown 52, sole 54,
rear 62, toe 60, and at least a portion of the heel 56. In some
embodiments, the body 98 further forms at least a portion of the
strikeface 64. In some embodiments, the body 98 comprises a front
opening that receives the faceplate 68. The faceplate 68 can be
welded, swedged (swagged), or otherwise secured to the body 98. The
body 98 can integrally comprise weighted portions and/or be
configured to receive at least one removable weight. The body 98 of
the golf club head 50 can be formed from a metal alloy material or
a polymer composite material.
[0030] In many embodiments, for example, those comprising driver
club heads, the loft angle 14 of the club head 50 is less than
approximately 16 degrees, less than approximately 15 degrees, less
than approximately 14 degrees, less than approximately 13 degrees,
less than approximately 12 degrees, less than approximately 11
degrees, or less than approximately 10 degrees. Further, in many
embodiments, the volume of the club head is greater than
approximately 400 cc, greater than approximately 425 cc, greater
than approximately 450 cc, greater than approximately 475 cc,
greater than approximately 500 cc, greater than approximately 525
cc, greater than approximately 550 cc, greater than approximately
575 cc, greater than approximately 600 cc, greater than
approximately 625 cc, greater than approximately 650 cc, greater
than approximately 675 cc, or greater than approximately 700 cc. In
some embodiments, the volume of the club head 50 can be
approximately 400 cc-600 cc, 425 cc-500 cc, approximately 500
cc-600 cc, approximately 500 cc-650 cc, approximately 550 cc-700
cc, approximately 600 cc-650 cc, approximately 600 cc-700 cc, or
approximately 600 cc-800 cc.
[0031] In many embodiments, for example, those comprising fairway
wood-type club heads, the loft angle 14 of the club head 50 is less
than approximately 35 degrees, less than approximately 34 degrees,
less than approximately 33 degrees, less than approximately 32
degrees, less than approximately 31 degrees, or less than
approximately 30 degrees. Further, in many embodiments, the loft
angle of the club head is greater than approximately 12 degrees,
greater than approximately 13 degrees, greater than approximately
14 degrees, greater than approximately 15 degrees, greater than
approximately 16 degrees, greater than approximately 17 degrees,
greater than approximately 18 degrees, greater than approximately
19 degrees, or greater than approximately 20 degrees. For example,
in some embodiments, the loft angle of the club head can be between
12 degrees and 35 degrees, between 15 degrees and 35 degrees,
between 20 degrees and 35 degrees, or between 12 degrees and 30
degrees.
[0032] In many embodiments, for example, those comprising fairway
wood-type club heads, the volume of the club head 50 is less than
approximately 400 cc, less than approximately 375 cc, less than
approximately 350 cc, less than approximately 325 cc, less than
approximately 300 cc, less than approximately 275 cc, less than
approximately 250 cc, less than approximately 225 cc, or less than
approximately 200 cc. In some embodiments, the volume of the club
head can be approximately 150 cc-200 cc, approximately 150 cc-250
cc, approximately 150 cc-300 cc, approximately 150 cc-350 cc,
approximately 150 cc-400 cc, approximately 300 cc-400 cc,
approximately 325 cc-400 cc, approximately 350 cc-400 cc,
approximately 250 cc-400 cc, approximately 250-350 cc, or
approximately 275-375 cc.
[0033] In many embodiments, for example, those comprising
hybrid-type club heads, the loft angle 14 of the club head 50 is
less than approximately 40 degrees, less than approximately 39
degrees, less than approximately 38 degrees, less than
approximately 37 degrees, less than approximately 36 degrees, less
than approximately 35 degrees, less than approximately 34 degrees,
less than approximately 33 degrees, less than approximately 32
degrees, less than approximately 31 degrees, or less than
approximately 30 degrees. Further, in many embodiments, the loft
angle of the club head is greater than approximately 16 degrees,
greater than approximately 17 degrees, greater than approximately
18 degrees, greater than approximately 19 degrees, greater than
approximately 20 degrees, greater than approximately 21 degrees,
greater than approximately 22 degrees, greater than approximately
23 degrees, greater than approximately 24 degrees, or greater than
approximately 25 degrees.
[0034] In many embodiments, for example, those comprising
hybrid-type club heads, the volume of the club head 50 is less than
approximately 200 cc, less than approximately 175 cc, less than
approximately 150 cc, less than approximately 125 cc, less than
approximately 100 cc, or less than approximately 75 cc. In some
embodiments, the volume of the club head can be approximately 100
cc-150 cc, approximately 75 cc-150 cc, approximately 100 cc-125 cc,
or approximately 75 cc-125 cc.
Metal Grain Structure of Faceplate
[0035] Referring to FIG. 4, the faceplate material of the golf club
head comprises a directional grain structure. The alloy metal
microstructure is made of grains (or units) 30 that can be formed
in a circular (or "equiaxed") fashion. As described below, the
directional grain structure is formed during the rolling process,
which turns a metal slab into a thinner sheet form. During rolling,
the grains 30 themselves are flattened and elongated during the
rolling process, creating elongated grains 32. This sheet is used
to form the faceplate and the long axis of the elongated grains 32
are aligned in roughly the same direction within the faceplate 68.
In some embodiments, the elongated grains 32 are aligned within
between 0-10 degrees, between 0-20 degrees, or between 0-30 degrees
of each other. The average angle of the elongated grains 32 defines
the orientation of the directional grain structure. The directional
grain structure causes the faceplate to exhibit anisotropy.
[0036] Referring to FIGS. 5 and 6, the orientation of the
directional grain structure is known as the longitudinal ("L")
direction 20. In other words, the elongated grains of the
directional grain structure are oriented in the longitudinal L
direction 20. The longitudinal L direction 20 corresponds to the
direction in which the faceplate material is rolled during
manufacturing. A transverse direction ("T") 22 is perpendicular to
the longitudinal L direction 20.
[0037] Referring to FIG. 5, the L direction 20 of the faceplate
material can be aligned so that it is angularly offset from the
horizontal reference axis 16 by an offset angle .theta.. The offset
angle .theta. is measured counterclockwise from the horizontal
reference axis 16. The offset angle .theta. can be greater than 0
and less than 90 degrees (0<0<90 degrees). In some
embodiments, the offset angle .theta. can range between 5 degrees
and 85 degrees. In some embodiments, the offset angle .theta. can
range between 10 and 80 degrees, 20 and 70 degrees, 30 and 60
degrees, 40 and 50 degrees, between 35 and 55 degrees, between 5
and 45 degrees, or between 45 and 85 degrees. In some embodiments,
the offset angle .theta. can be 5 degrees, 10 degrees, 15 degrees,
20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45
degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70
degrees, 75 degrees, 80 degrees, or 85 degrees. The offset angle
.theta. determines the material properties of the strikeface 64
along the horizontal and the vertical reference axes 16, 18 of the
club head 50.
[0038] The faceplate material can comprise a modulus of elasticity
ranging between 98.5 GPa and 151.7 GPa (14 Mpsi-22 Mpsi). Due to
the anisotropy of the faceplate 64, the modulus of elasticity
differs between the longitudinal L direction 20 and the traverse T
direction 22. The modulus of elasticity measured in the L direction
20 is lower than the modulus of elasticity measured in the T
direction 22. The modulus of elasticity in the L direction 20 can
range between 98.5 GPa and 151.7 GPa (14 Mpsi-22 Mpsi). In some
embodiments, the modulus of elasticity in the L direction 20 can be
98 GPa, 99 GPa, 100 GPa, 101 GPa, 102 GPa, 103 GPa, 104 GPa, 105
GPa, 106 GPa, 107 GPa, 108 GPa, 109 GPa, 110 GPa, 111 GPa, 112 GPa,
113 GPa, 114 GPa, 115 GPa, 116 GPa, 117 GPa, 118 GPa, 119 GPa, 120
GPa, 121 GPa, 122 GPa, 123 GPa, 124 GPa, 125 GPa, 126 GPa, 127 GPa,
128 GPa, 129 GPa, 130 GPa, 132 GPa, 134 GPa, 126 GPa, 128 GPa, 130
GPa, 132 GPa, 134 GPa, 136 GPa, 138 GPa, 140 GPa, 142 GPa, 144 GPa,
146 GPa, 148 GPa, or 150 GPa. The modulus of elasticity in the T
direction 22 can range between 118 GPa and 146 GPa (17.11
Mpsi-21.17 Mpsi). In some embodiments, the modulus of elasticity in
the T direction 22 can be between 118 GPa and 122 GP, 122 GPa and
126 GPa, 126 GPa and 130 GPa, 130 GPa and 134 GPa, 134 GPa and 138
GPa, 138 GPa and 142 GPa, or 142 GPa and 146 GPa.
[0039] Additionally, the modulus of elasticity can be measured
along any direction between the L and T directions 20, 22. By
nature of the material structure, the modulus of elasticity along a
direction between the L and T directions has a value between the
modulus of elasticity in the L direction 20 and the modulus of
elasticity in the T direction 22. The modulus of elasticity
measured at 45 degrees from the L direction 20 (between the L and T
directions) can range between 110 GPa and 131 GPa (16 Mpsi-19
Mpsi). In some embodiments, the modulus of elasticity measured at
45 degrees from the L direction 20 can range between 110 GPa and
130 GPa, 110 GPa and 120 GPa, 113 GPa and 119 GPa, or 118 GPa and
125 GPa. In some embodiments, the modulus of elasticity measured at
45 degrees from the L direction 20 can be 110 GPa, 111 GPa, 112
GPa, 113 GPa, 114 GPa, 115 GPa, 116 GPa, 117 GPa, 118 GPa, 119 GPa,
120 GPa, 121 GPa, 122 GPa, 123 GPa, 124 GPa, 125 GPa, 126 GPa, 127
GPa, 128 GPa, 129 GPa, 130 GPa, or 131 GPa.
[0040] In the embodiment of FIG. 6, the faceplate material
longitudinal L direction 20 is aligned with the horizontal
reference axis 16 of the club head 50. The transverse T direction
22 of the faceplate material is aligned with the vertical reference
axis 18 of the club head 50. In this embodiment, the modulus of
elasticity in the horizontal reference axis direction 16 will be
lower than the modulus of elasticity measured in the vertical
reference axis direction 18. The horizontal modulus of elasticity
(along the width 90) has a greater effect on faceplate flexibility
than the vertical modulus of elasticity (along the height 92),
because the faceplate's width 90 is greater than the faceplate's
height 92. Therefore, a faceplate 68 having a lower horizontal
modulus of elasticity than vertical modulus of elasticity will flex
or bend more freely than faceplates lacking this anisotropic
property/configuration. For example, consider a golf club head (not
shown) wherein the faceplate material longitudinal L direction 20
is aligned with the vertical reference axis 18 of the club head 50,
and the transverse T direction 22 is aligned with the horizontal
reference axis 16. In this golf club head 50, the horizontal
modulus of elasticity (along the width 90) will be higher than the
vertical modulus of elasticity (along the height 92). Therefore,
this faceplate 68 would flex or bend less, and transfer less energy
back to an impacted golf ball.
[0041] The offset angle .theta. can be altered to control the
modulus of elasticity in the horizontal direction. As described
above, an increase in the modulus of elasticity will lower CT,
while a decrease in the modulus of elasticity will raise CT.
Therefore, altering the offset angle .theta. indirectly controls
the CT of the strikeface. Angularly offsetting the directional
grain structure of the faceplate material so that it is off-axis
(that is angled from the horizontal reference axis 16), allows the
strikeface 64 to exhibit a horizontal modulus of elasticity value
that is in-between the material longitudinal L direction 20 modulus
and the transverse T direction 22 modulus. In some embodiments, a
faceplate with an offset angle .theta. of approximately 45 degrees
can exhibit a horizontal modulus of elasticity between 116 GPa and
130 GPa, 116 GPa and 120 GPa, 117 GPa and 119 GPa, or 118 GPa and
125 GPa.
[0042] A faceplate with a steeper (greater) offset angle .theta.
exhibits a higher modulus of elasticity in the horizontal reference
axis direction 16 than a faceplate with a shallower (lesser) offset
angle .theta.. A faceplate with a shallower (lesser) offset angle
.theta. exhibits a lower modulus of elasticity in the horizontal
reference axis direction 16 than a faceplate with a steeper
(greater) offset angle .theta.. A steeper (greater) offset angle
.theta. will result in a lower CT than a shallower (lesser) offset
angle .theta.. A shallower (lesser) offset angle .theta. will
result in a higher CT than a steeper (greater) offset angle
.theta.. Therefore, the offset angle .theta. can be set/designed at
a value that retains the CT value below the required threshold set
by the USGA (239 .mu.s+/-18 .mu.s across impact area).
[0043] In addition to controlling overall CT of the strikeface 64,
in some embodiments, the off-axis directional grain structure can
also locally control CT within regions of the strikeface 64. The
geometry of a golf club head 50 causes a strikeface 64 to have
points of higher and lower CT across the strikeface 64. Typically,
the high-toe region 70 exhibits the highest CT values. To maximize
the energy transferred to an impacted golf ball, the CT must be as
high as possible at all points on the strikeface 64, not only in
the high-toe region 70. Angling the faceplate longitudinal L
direction 20 from the low-toe region 74 towards the high-heel
region 72, causes the low-heel region 76 and the high-toe region 70
to have lower CT values than the low-toe region 74 and high-heel
region 72. Angling the directional grain structure from the low-toe
region 74 to the high-heel region 72 (at an offset angle .theta.),
encourages a more uniform CT across the strikeface 64 since it
lowers the CT in the hottest high-toe region 70 of the strikeface
64.
[0044] To quantify the uniformity of the CT across the strikeface
64, a CT differential can be measured as the difference between a
maximum CT and a minimum CT of the strikeface 64. A strikeface with
a directional grain structure aligned parallel with the horizontal
reference axis 16 (i.e. a heel-to-toe alignment) can comprise a CT
differential across the face of greater than or equal to 5 .mu.s.
In some embodiments, the CT differential for a heel-to-toe
directional grain structure can be between 5-10 .mu.s. In
comparison, a strikeface 64 with a directional grain structure
angled at an offset angle .theta. of 45 degrees, can comprise a CT
differential of less than or equal to 5 .mu.s, less than or equal
to 4 .mu.s, less than or equal to 3 .mu.s, or between 0-5 .mu.s. In
some embodiments, the CT differential for the herein described
strikeface 64 can range between 0-1 .mu.s, 1-2 .mu.s, 2-3 .mu.s,
3-4 .mu.s, or 4-5 .mu.s. In some embodiments, the CT differential
can be 0 .mu.s, 1 .mu.s, 2 .mu.s, 3 .mu.s, 4 .mu.s, or 5 .mu.s.
[0045] By creating a more uniform CT across the face, the overall
CT can be increased without breaching the USGA pendulum test
requirements. More specifically, in some embodiments, the CT at the
geometric center 66 and/or sweet spot of the strikeface 64 can be
increased. In some embodiments, the off-axis alignment of the
directional grain structure, with offset angle .theta.>0, can
provide a ball speed increase of between 0.25 and 5 mph (compared
to a horizontal grain structure strikeface, with offset angle
.theta.=0). In some embodiments, the off-axis alignment of the
directional grain structure allows for a ball speed increase of 1/4
mph, 1/2 mph, 3/4 mph, 1 mph, 1.5 mph, 2 mph, 2.5 mph, 3 mph, 3.5
mph, 4 mph, 4.5 mph, 5 mph, or any value therebetween.
[0046] The faceplate 68 can be formed from a metal alloy, such as a
steel, a titanium alloy, or any other suitable metal material. In
some embodiments, the faceplate material is a steel alloy, such as
C300 steel, C350 steel, 455 steel, 431 steel, 475 steel, 565 steel,
17-4 stainless steel, maraging steel, Ni--Co--Cr steel alloy,
AerMet 310 steel, or AerMet 340 steel. In some embodiments, the
faceplate material is an a-P titanium (a-P Ti) alloy. The a-P Ti
alloy may contain neutral alloying elements such as tin and a
stabilizers such as aluminum and oxygen. The a-P Ti alloy may
contain P-stabilizers such as molybdenum, silicon and vanadium. All
numbers described below regarding weight percent are a total weight
percent (wt %). The total weight percent of a-stabilizer aluminum
in a-P Ti alloy may be between 2 wt % to 10 wt %, 3 wt % to 9 wt %,
4 wt % to 8 wt %, 5 wt % to 7 wt %, 2 wt % to 20 wt %, 3 wt % to 19
wt %, 4 wt % to 18 wt %, 5 wt % to 17 wt %, 6 wt % to 16 wt %, 7 wt
% to 15 wt %, 8 wt % to 14 wt %, 9 wt % to 13 wt %, 10 wt % to 12
wt %, 7 wt % to 9 wt %, 7 wt % to 10 wt %, 7 wt % to 11 wt %, 7 wt
% to 12 wt %, 7 wt % to 13 wt %, 7 wt % to 14 wt %, 7 wt % to 15 wt
%, 7 wt % to 16 wt %, 7 wt % to 17 wt %, 7 wt % to 18 wt %, 7 wt %
to 19 wt %, 7 wt % to 20 wt %, 8 wt % to 10 wt %, 8 wt % to 11 wt
%, 8 wt % to 12 wt %, 8 wt % to 13 wt %, 8 wt % to 14 wt %, 8 wt %
to 15 wt %, 8 wt % to 16 wt %, 8 wt % to 17 wt %, 8 wt % to 18 wt
%, 8 wt % to 19 wt %, 8 wt % to 20 wt %, 9 wt % to 11 wt %, 9 wt %
to 12 wt %, 9 wt % to 13 wt %, 9 wt % to 14 wt %, 9 wt % to 15 wt
%, 9 wt % to 16 wt %, 9 wt % to 17 wt %, 9 wt % to 18 wt %, 9 wt %
to 19 wt %, 9 wt % to 20 wt %, 10 wt % to 13 wt %, 10 wt % to 14 wt
%, 10 wt % to 15 wt %, 10 wt % to 16 wt %, 10 wt % to 17 wt %, 10
wt % to 18 wt %, 10 wt % to 19 wt %, 10 wt % to 20 wt %, 11 wt % to
13 wt %, 11 wt % to 14 wt %, 11 wt % to 15 wt %, 11 wt % to 16 wt
%, 11 wt % to 17 wt %, 11 wt % to 18 wt %, 11 wt % to 19 wt %, 11
wt % to 20 wt %, 12 wt % to 14 wt %, 12 wt % to 15 wt %, 12 wt % to
16 wt %, 12 wt % to 17 wt %, 12 wt % to 18 wt %, 12 wt % to 19 wt
%, 12 wt % to 20 wt %, 13 wt % to 15 wt %, 13 wt % to 16 wt %, 13
wt % to 17 wt %, 13 wt % to 18 wt %, 13 wt % to 19 wt %, 13 wt % to
20 wt %, 14 wt % to 16 wt %, 14 wt % to 17 wt %, 14 wt % to 18 wt
%, 14 wt % to 19 wt %, 14 wt % to 20 wt %, 15 wt % to 17 wt %, 15
wt % to 18 wt %, 15 wt % to 19 wt %, 15 wt % to 20 wt %, 16 wt % to
18 wt %, 16 wt % to 19 wt %, 16 wt % to 20 wt %, 17 wt % to 19 wt
%, 17 wt % to 20 wt %, or 18 wt % to 20 wt %.
[0047] In certain embodiments, the total weight percent of
a-stabilizer aluminum in a-P Ti alloy may be between 7 wt % to 13
wt %, 8 wt % to 13 wt %, 9 wt % to 13 wt %, 10 wt % to 13 wt %, 11
wt % to 13 wt %, or 12 wt % to 13 wt %. The total weight percent of
a-stabilizer oxygen in a-P Ti alloy may be between 0.05 wt % to
0.35 wt %, or 0.10 wt % to 0.20 wt %. The total weight percent of
0-stabilizer molybdenum in a-P Ti alloy may be between 0.2 wt % to
1.0 wt %, or 0.6 wt % to 0.8 wt %, or trace amounts. The total
weight percent of P-stabilizer vanadium in a-P Ti alloy may be
between 1.5 wt % to 7 wt %, or 3.5 wt % to 4.5 wt %. The total
weight percent of P-stabilizer silicon in a-P Ti alloy may be
between 0.01 to 0.10 wt %, or 0.03 wt % to 0.07 wt %. The a-P Ti
alloy may be Ti-6Al-4V (or Ti 6-4), Ti-7S+(or Ti-7S, T-7S, or
ST721), Ti-9S (or T-9S), Ti-9S+, HST-180, FS2S, Super-TiX 51AF,
Super-TiX 51 Premium, Ti-662, Ti-8-1-1, Ti-65K, Ti-6246, or IMI
550.
[0048] Referring to FIGS. 7 and 8, to provide region-specific
strength and uniform CT, some embodiments of the club head 50
described herein can also comprise a varying thickness across the
strikeface 64. The strikeface 64 comprises an inner surface 84 and
an outer surface 86. A strikeface thickness 88 is measured between
the inner surface 84 and the outer surface 86, perpendicular to the
loft plane 12. The strikeface thickness 88 can differ between
regions of the strikeface 64. The strikeface 64 can comprise a
central region 78 overlapping a sweet spot and/or the geometric
center 66 of the strikeface 64, a transition region 80 adjacent and
surrounding the central region 78, and a peripheral region 82
adjacent and surrounding the transition region 80. The peripheral
region 82 of the strikeface 64 can be adjacent the toe 60, heel 56,
crown 52, and sole 54 edges of the club head 50. The central region
78 can have a thickness 88 greater than the transition region 80
and/or the peripheral region 82 of the strikeface 64. The
peripheral region 82 of the strikeface 64 can be the thinnest
portion of the strikeface 64. The thickness differences between the
regions of the strikeface 64 can cause the inner surface 84 of the
strikeface 64 to be non-planar. In some embodiments, the variable
face thickness of the strikeface 64 results in an oval-shaped or
egg-shaped thickened region. The position and shape of this
thickened region can provide additional CT control by reducing the
CT within the thickened region.
[0049] A minimum thickness of the strikeface 64 can be between 1.5
millimeters (0.059 inch) and 0.4 millimeters (0.016 inch). In some
embodiments, the minimum thickness of the strikeface 64 can be 1.5
millimeters, 1.4 millimeters, 1.3 millimeters, 1.2 millimeters, 1.1
millimeters, 1.0 millimeters, 0.9 millimeters, 0.8 millimeters, 0.7
millimeters, 0.6 millimeters, 0.5 millimeters, or 0.4
millimeters.
[0050] A maximum thickness of the strikeface 64 can be between 1.5
millimeters (0.059 inch) and 5 millimeters (0.197 inch). In some
embodiments, the maximum thickness of the strikeface can be between
1.5 millimeters and 3.0 millimeters, 3.0 millimeters and 4.0
millimeters, 3.2 millimeters and 4.2 millimeters, 3.4 millimeters
and 4.4 millimeters, or greater than 4.4. millimeters.
[0051] The strikeface 64 can further comprise a curvature defined
by a bulge radius and roll radius. The bulge radius is measured in
a toe-to-heel direction across the strikeface 64 and can range
between 8 and 14 inches. In some embodiments, the bulge radius can
be 8 inches, 9 inches, 10 inches, 11 inches, 12 inches, 13 inches,
or 14 inches. The roll radius is measured in a crown-to-sole
direction across the strikeface 64 and can range between 7 and 15
inches. In some embodiments, the roll radius is 7 inches, 8 inches,
9 inches, 10 inches, 11 inches, 12 inches, 13 inches, 14 inches, or
15 inches. In some embodiments, the bulge and roll radii are
constant across the strikeface 64, but in other embodiments one or
both of the bulge and roll radii vary across the strikeface. The
formation of the bulge and roll radii negligibly affects the grain
structure of the strikeface material.
Method of Manufacture
[0052] To produce the faceplate 68, a sheet of the desired
strikeface material is subject to a rolling process. The raw
material comprises an equiaxed grain structure. The raw material
sheet is pressed and forced between two opposing rollers to reduce
the thickness of the sheet. This rolling process is repeated
multiple times in the same direction, until the desired sheet
thickness is reached. The sheets are typically rolled 2 to 15
times. The repeated rolling alters the grain structure of the
material, causing the equiaxed grains to deform into elongated
grains. The elongated grains are oriented in the direction that the
rolling occurs.
[0053] The rolling process can be done as a cold rolling process or
a hot rolling process. A hot rolling process is done with material
temperatures over 200 degrees Centigrade. Hot rolling is often done
between 700 and 1000 degrees Centigrade. A cold rolling process is
done with material temperatures under 200 degrees Centigrade. Cold
rolling can be done at any temperature between 0 and 200 degrees
Centigrade. In some embodiments, the faceplate 64 is formed by a
combination of hot rolling and cold rolling. A hot rolling process
can be repeated 2 to 7 times. Next, a cold rolling process can be
repeated 5 to 7 times. The sheets are not annealed or heat treated
after rolling, because further processing the material at a high
temperature could alter or destroy the elongated grain
structure.
[0054] After the rolling of the sheet material, one or more
faceplates can be stamped, laser cut, or punched from the sheet
material. In some embodiments, the one or more faceplates are
milled, either prior to or after stamping. The inner surface of
each faceplate can be milled to create the variable face thickness.
Once the faceplate is prepared, it can be attached into a receiving
opening on the body of the club head. The club head body can be
cast, forged, or otherwise produced. The faceplate can be welded or
swedged (swagged) into the receiving opening of the body.
[0055] The sheets which are rolled prior to the stamping of the
faceplates have set width and length dimensions. Angling the
faceplates allows more faceplates to be produced from each sheet,
thus reducing waste metal. For example, when the faceplates are
stamped so that the grain structure is oriented with the
longitudinal L direction running heel to toe, approximately 504
faceplates can be stamped out of each sheet. However, when the
faceplates are stamped so that the grain structure is oriented at a
45 degree angle (LTHH or HTLH), each sheet yields 540 faceplates.
Therefore, the angled grain structure not only helps with CT
control, but also reduces waste and manufacturing cost.
Example 1
[0056] A CT comparison test was done between a control set of
faceplates, a first set of example faceplates, a second set of
example faceplates, and a third set of example faceplates. The
control set of faceplates comprised a heel-to-toe oriented
directional grain structure. The first set of example faceplates
comprised a crown-to-sole oriented directional grain structure. The
second set of example faceplates comprised a low-toe to high-heel
(LTHH) oriented directional grain structure. The third set of
example faceplates comprised a high-toe to low-heel (HTLH) oriented
directional grain structure. Each of the sets of faceplates
(control, first, second, and third) comprised five faceplates. The
control, first, second, and third sets of faceplates were all
formed from T9S+ titanium alloy material.
[0057] Every faceplate within the control, first, second, and third
sets of faceplates comprised the same face thickness profile. The
faceplates comprised a variable face thickness, with a minimum
thickness of 0.089 inch (2.26 mm) and a maximum thickness of 0.139
inch (3.53 mm).
[0058] Measurements were taken of the average CT at the geometric
center of each faceplate and the average CT in the high-toe region
of the faceplate. The first, second, and third sets of example
faceplates comprised average CT values lower than the control set
at both the geometric center and in the high-toe region. Table I,
below, presents the results of the CT comparison.
TABLE-US-00001 TABLE I Example 1 CT Results Control First Second
Third (heel-to-toe) (crown-to-sole) (LTHH) (HTLH) Center CT Avg
244.3 237.6 238.4 238.0 High Toe CT Avg 250.2 242.6 242.4 241.6 CT
Differential 5.9 5.0 4.0 3.6
[0059] The first, second, and third sets of example faceplates
exhibited lower CT without compromising the durability of the
faceplates. Orienting the directional grain structure of the
faceplate material at an offset angle from the horizontal reference
axis reduces the CT. Using directional grain structure to control
CT can prevent the faceplate from exceeding the maximum CT limit
for conformance (239 .mu.s+/-18 .mu.s). Additionally, the second
(LTHH) and third (HTLH) sets of example faceplates exhibited lower
CT differentials than the control (heel-to-toe) and first
(crown-to-sole) sets. Therefore, the second and third faceplate
sets would both provide a golfer with a more uniform response
across the face and allow the golf club designer to raise the
average CT through other club head technologies without exceeding
the USGA CT limit.
Example 2
[0060] A durability test was done between a control set and a
first, second, and third set of example faceplates, similar to the
first, second, and third sets of example faceplates introduced in
Example 1 above. The first set of example faceplates comprised a
crown-to-sole oriented directional grain structure. The second set
of example faceplates comprised a low-toe to high-heel (LTHH)
oriented directional grain structure. The third set of example
faceplate comprised a high-toe to low-heel (HTLH) oriented
directional grain structure. All the example faceplate sets were
formed from T9S+ titanium alloy material. In this durability test,
each of the sets of faceplates (first, second, and third) comprised
three faceplates.
[0061] Every faceplate within the control, first, second, and third
sets of faceplates comprised the same face thickness profile. The
faceplates comprised a variable face thickness, with a minimum
thickness of 2.26 mm (0.089 inch) and a maximum thickness of 3.53
mm (0.139 inch).
[0062] The control, the first, second, and third sets of example
faceplates were each repeatedly impacted by a golf ball traveling
at a speed of approximately 120 mph. The testing was conducted
using an air cannon system. The number of hits to failure was
tested for the each faceplate set. The control set endured on
average approximately 2700 hits from a golf ball traveling at
approximately 120 mph before failure. The first set of example
faceplates endured on average approximately 1400 hits from a golf
ball traveling at approximately 120 mph before failure. The second
set of example faceplates (LTHH) endured on average approximately
2150 hits from a golf ball traveling at approximately 120 mph
before failure. The third set of example faceplates (HTLH) endured
on average approximately 2120 hits from a golf ball traveling at
approximately 120 mph before failure. Therefore, both the second
set of example faceplates, having low-toe to high-heel oriented
directional grain structure, and the third set of example
faceplates, having high-toe to low-heel oriented directional grain
structure, were more durable than the first set of example
faceplates, having crown-to-sole oriented directional grain
structure. Although the control set was slightly more durable than
the second and third sets of example faceplates, any faceplate that
endures 2000 hits or more without failure is considered highly
durable and suitable for professional performance.
[0063] The durability of the second and third sets differed by less
than 8 shots out of over 2100 shots. Therefore, this durability
test revealed that faceplates with a low-toe to high-heel (LTHH)
oriented directional grain structure and faceplates with a high-toe
to low-heel (HTLH) oriented directional grain structure exhibit
roughly equivalent durability. Combining this knowledge with the
results from Example 1 above, an angled grain structure (either
LTHH or HTLH) maintains sufficient durability (over 2000 hits at
120 mph), while also beneficially reducing the CT value.
Durability
[0064] Golfers hit most often within the low-heel region and/or
high-toe region of the strikeface. The mechanics of a golf swing
causes this higher probability of hits within the low-heel region
and high-toe region. A dispersion of shots across a strikeface
often falls within an elliptical region whose major axis is angled
from the low-heel region to the high-toe region. In some
embodiments, this elliptical hit region major axis (not shown) is
angled clockwise from the horizontal reference axis by between 0
and 90 degrees. To maintain long-term durability of a strikeface,
the faceplate material must be strong enough to withstand these hit
impacts. In theory. the strength of the faceplate material is
greater along the longitudinal L direction than along the
transverse T direction. Therefore, in prior art club heads, the
longitudinal L direction has been aligned from the high-toe region
to the low-heel region (HTLH). In other words, the longitudinal L
direction has been aligned approximately parallel to the major axis
of the elliptical mishit region. However, as shown in Example 2
below, in actuality, a faceplate with the longitudinal L direction
aligned low-toe to high heel (LTHH) exhibits equal or greater
durability than a faceplate with the longitudinal L direction
aligned high-toe to low-heel (HTLH).
[0065] Aligning the longitudinal L direction of the grain structure
in either a LTHH or HTLH direction results in a durability that is
greater than the durability exhibited by a faceplate with the
longitudinal L direction aligned crown to sole. In some
embodiments, faceplates with LTHH or HTLH orientations are able to
withstand up to 30% more hits, 40% more hits, 50% more hits, 60%
more hits, or 70% more hits than a faceplate with a crown to sole
oriented grain structure.
[0066] Although aligning the longitudinal L direction of the grain
structure in either a LTHH or HTLH direction reduces the durability
compared to a heel to toe alignment, the LTHH and HTLH orientations
maintain sufficient durability to withstand up to at least 2000
hits without failure.
[0067] The herein described low-toe to high-heel (LTHH) angulation
of the faceplate material increases the modulus of elasticity
within the high-toe and low-heel regions. This increase of the
modulus of elasticity within the high-toe and low-heel regions
reduces the CT within said regions and thus lowers the CT
differential across the strikeface. The lower CT differential
allows the overall CT or the CT at the geometric center to be
raised without any region within the strikeface impact area
reaching the maximum CT limit for conformance (239 .mu.s+/-18
.mu.s). A higher overall CT and/or a higher CT at the geometric
center of the strikeface can increase the rebound and ball speed
potential of the strikeface. In addition to providing an increase
in the rebound properties of the overall strikeface, the uniform CT
(low CT differential) causes the herein described club head to
respond to impact more consistently, regardless of the region of
the strikeface that is impacted. This consistency allows a golfer
to more accurately predict where his or her shot will land and/or
the distance a shot will travel.
[0068] As the rules to golf may change from time to time (e.g., new
regulations may be adopted or old rules may be eliminated or
modified by golf standard organizations and/or governing bodies),
golf equipment related to the methods, apparatus, and/or articles
of manufacture described herein may be conforming or non-conforming
to the rules of golf at any particular time. Accordingly, golf
equipment related to the methods, apparatus, and/or articles of
manufacture described herein may be advertised, offered for sale,
and/or sold as conforming or non-conforming golf equipment. The
methods, apparatus, and/or articles of manufacture described herein
are not limited in this regard.
[0069] Although a particular order of actions is described above,
these actions may be performed in other temporal sequences. For
example, two or more actions described above may be performed
sequentially, concurrently, or simultaneously. Alternatively, two
or more actions may be performed in reversed order. Further, one or
more actions described above may not be performed at all. The
apparatus, methods, and articles of manufacture described herein
are not limited in this regard.
[0070] While the invention has been described in connection with
various aspects, it will be understood that the invention is
capable of further modifications. This application is intended to
cover any variations, uses or adaptation of the invention
following, in general, the principles of the invention, and
including such departures from the present disclosure as come
within the known and customary practice within the art to which the
invention pertains.
* * * * *
References