U.S. patent application number 15/379906 was filed with the patent office on 2017-04-06 for variable thickness golf club head and method of manufacturing the same.
This patent application is currently assigned to Acushnet Company. The applicant listed for this patent is Acushnet Company. Invention is credited to Uday V. Deshmukh, Gentry Ferguson, Takeshi Casey Funaki, Stephanie Luttrell, Mark C. Myrhum.
Application Number | 20170095711 15/379906 |
Document ID | / |
Family ID | 58447269 |
Filed Date | 2017-04-06 |
United States Patent
Application |
20170095711 |
Kind Code |
A1 |
Ferguson; Gentry ; et
al. |
April 6, 2017 |
VARIABLE THICKNESS GOLF CLUB HEAD AND METHOD OF MANUFACTURING THE
SAME
Abstract
A method of forming a crown of a golf club head including
casting the crown of the golf club head, the crown including an
internal surface adjacent a hollow interior of the golf club head,
and an external surface opposite the internal surface, the crown
including a first region and a second region adjacent the first
region, the first region including a recess formed in the internal
surface, the first region including a sacrificial protrusion on the
external surface extending outwards beyond the second region;
applying a mask to the external surface of the second region;
exposing the crown of the golf club head to an etching chemical,
wherein the etching chemical removes the sacrificial protrusion
from the external surface of the crown; removing the etching
chemical from the crown of the golf club head; and removing the
mask from the second region.
Inventors: |
Ferguson; Gentry;
(Encinitas, CA) ; Funaki; Takeshi Casey; (San
Diego, CA) ; Luttrell; Stephanie; (Carlsbad, CA)
; Myrhum; Mark C.; (Del Mar, CA) ; Deshmukh; Uday
V.; (Carlsbad, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Acushnet Company |
Fairhaven |
MA |
US |
|
|
Assignee: |
Acushnet Company
Fairhaven
MA
|
Family ID: |
58447269 |
Appl. No.: |
15/379906 |
Filed: |
December 15, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14330165 |
Jul 14, 2014 |
|
|
|
15379906 |
|
|
|
|
13467102 |
May 9, 2012 |
|
|
|
14330165 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A63B 53/0437 20200801;
A63B 53/0408 20200801; A63B 2209/00 20130101; A63B 53/0466
20130101; A63B 60/00 20151001; A63B 53/0416 20200801; B21K 25/00
20130101; A63B 53/0425 20200801; A63B 53/0458 20200801; B21D 31/00
20130101; C23F 1/02 20130101; B21K 17/00 20130101; A63B 53/0429
20200801; A63B 53/04 20130101; B21K 23/00 20130101; A63B 53/045
20200801 |
International
Class: |
A63B 53/04 20060101
A63B053/04 |
Claims
1. A method of forming a crown of a golf club head, comprising:
casting said crown of said golf club head, said crown of said golf
club head comprising an internal surface adjacent a hollow interior
of said golf club head, and an external surface opposite said
internal surface, said crown of said golf club head comprising a
first region and a second region adjacent said first region, said
second region substantially surrounding said first region, said
first region comprising a recess formed in said internal surface,
said first region comprising a sacrificial protrusion on said
external surface extending outwards beyond said second region,
wherein said first region of has an as-cast thickness T.sub.1, and
thickness T.sub.1 is greater than or equal to 0.48 mm; applying a
mask to said external surface of said second region; exposing said
crown of said golf club head to an etching chemical, wherein said
etching chemical removes said sacrificial protrusion from said
external surface of said crown; removing said etching chemical from
said crown of said golf club head; and removing said mask from said
second region.
2. A method of forming a portion of a golf club head, comprising:
casting said portion of said golf club head, said portion of said
golf club head comprising an internal surface adjacent a hollow
interior of said golf club head, and an external surface opposite
said internal surface, said portion of said golf club head
comprising a first region and a second region adjacent said first
region, said first region comprising a recess formed in said
internal surface, said first region comprising a sacrificial
protrusion on said external surface extending outwards beyond said
second region; applying a mask to said external surface of said
second region; exposing said portion of said golf club head to an
etching chemical; removing said etching chemical from said portion
of said golf club head; and removing said mask from said second
region.
3. The method of claim 2, further comprising polishing said
external surface of said portion of said golf club head.
4. The method of claim 2, wherein said first region of has an
as-cast thickness T.sub.1, and thickness T.sub.1 is greater than or
equal to 0.48 mm.
5. The method of claim 4, wherein said thickness T.sub.1 of said
first region, after exposing said portion of said golf club head to
an etching chemical, is reduced to less than or equal to 0.45
mm.
6. The method of claim 4, wherein said thickness T.sub.1 of said
first region, after exposing said portion of said golf club head to
an etching chemical, is reduced to less than or equal to 0.35
mm.
7. The method of claim 4, wherein said thickness T.sub.1 of said
first region, after exposing said portion of said golf club head to
an etching chemical, is reduced to less than or equal to 0.25
mm.
8. The method of claim 2, wherein exposing said portion of said
golf club head to an etching chemical removes said sacrificial
protrusion from said first region.
9. The method of claim 2, wherein exposing said portion of said
golf club head to an etching chemical is completed when said
external surface is substantially flush at the intersection of said
first region and said second region.
10. The method of claim 2, wherein said second region substantially
surrounds said first region.
11. The method of claim 2, wherein said second region has a
thickness T.sub.2, and wherein said recess has a depth D.sub.r, and
wherein D.sub.r is greater than or equal to T.sub.2/2.
12. A method of forming a crown of a golf club head, comprising:
casting said crown of said golf club head, said crown of said golf
club head comprising an internal surface adjacent a hollow interior
of said golf club head, and an external surface opposite said
internal surface, said crown of said golf club head comprising a
first region and a second region adjacent said first region, said
first region comprising a recess formed in said internal surface,
said first region comprising a sacrificial protrusion on said
external surface extending outwards beyond said second region;
applying a mask to said external surface of said second region;
exposing said crown of said golf club head to an etching chemical,
wherein said etching chemical removes said sacrificial protrusion
from said external surface of said crown; removing said etching
chemical from said crown of said golf club head; and removing said
mask from said second region.
13. The method of claim 12, further comprising polishing said
external surface of said crown of said golf club head.
14. The method of claim 12, wherein said first region of has an
as-cast thickness T.sub.1, and thickness T.sub.1 is greater than or
equal to 0.48 mm.
15. The method of claim 14, wherein said thickness T.sub.1 of said
first region, after exposing said crown of said golf club head to
an etching chemical, is reduced to less than or equal to 0.45
mm.
16. The method of claim 14, wherein said thickness T.sub.1 of said
first region after exposing said crown of said golf club head to an
etching chemical is reduced to less than or equal to 0.35 mm.
17. The method of claim 14, wherein said thickness T.sub.1 of said
first region after exposing said crown of said golf club head to an
etching chemical is reduced to less than or equal to 0.25 mm.
18. The method of claim 12, wherein exposing said crown of said
golf club head to an etching chemical is completed when said
external surface is substantially flush at the intersection of said
first region and said second region.
19. The method of claim 12, wherein said second region
substantially surrounds said first region.
20. The method of claim 12, wherein said second region has a
thickness T.sub.2, and wherein said recess has a depth D.sub.r, and
wherein D.sub.r is greater than or equal to T.sub.2/2.
Description
RELATED APPLICATIONS
[0001] The current application is a continuation-in-part (CIP) of
U.S. patent application Ser. No. 14/330,165, filed on Jul. 14,
2014, currently pending, which is a continuation-in-part (CIP) of
U.S. patent application Ser. No. 13/467,102, filed on May 9, 2012,
abandoned, the disclosure of which are incorporated by reference in
their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a variable thickness golf
club head and a method of manufacturing the same. More
specifically, the present invention relates to systems, devices,
and methods related to constructing portions of a golf club head
incorporating variable thickness.
BACKGROUND OF THE INVENTION
[0003] Ever since the metalwood golf club burst onto the scene to
replace the traditional persimmon wood, golf club designers have
constantly sought to find ways to improve upon this groundbreaking
design.
[0004] U.S. Pat. No. 5,474,296 to Schmidt et al. illustrate one of
the earlier attempts to improve upon the design opportunity created
by a hollow metalwood golf club by disclosing a golf club with a
variable faceplate thickness. One way a variable faceplate
thickness improves the performance of a metalwood club is by
reducing the amount of weight at low stress areas of the striking
faceplate to create more discretionary weight that can be placed at
alternative locations in the golf club head to improve the
performance of the golf club head. In addition to the above
benefit, the incorporation of variable faceplate thickness can also
improve upon the performance of the golf club head by adjusting the
coefficient of restitution of the striking face.
[0005] U.S. Pat. No. 6,863,626 to Evans et al. illustrates this
secondary benefit of adjusting the coefficient of restitution of a
golf club by disclosing a golf club having a striking plate with
regions of varying thickness. More specifically, U.S. Pat. No.
6,863,626 identifies this benefit by indicating that striking plate
having regions of varying thickness allows for more compliance
during impact with a golf ball, which in turn, could generate more
ballspeed.
[0006] U.S. Pat. No. 7,137,907 to Gibbs et al. illustrates the
ability to further improve upon the design of a striking face
having a variable face thickness for a purpose that is different
from saving weight and improving coefficient of restitution. More
specifically, U.S. Pat. No. 7,137,907 illustrates a way to expand
upon the "sweet spot" of a golf club head in order to conform to
the rules of golf that puts a cap on the maximum coefficient of
restitution allowed by a golf club. U.S. Pat. No. 7,137,907 does
this by disclosing a golf club face or face insert wherein the face
has an interior surface with a first thickness section and a second
thickness region. The first thickness section preferably has a
thickness that is at least 0.025 inch greater than the thickness of
the second thickness region. The face or face insert with variable
thickness allows for a face or face insert with less mass in a golf
club head that conforms to the United States Golf Association
regulations.
[0007] With the incorporation of variable face thickness into
hollow metalwood type golf club heads, various methodologies of
manufacturing have been developed to create this complicated
geometry. U.S. Pat. No. 6,354,962 to Galloway et al. illustrates
one methodology to create a striking wherein the face member is
composed of a single piece of metal, and is preferably composed of
a forged metal material, more preferably a forged titanium
material. However, due to the need for precise geometry, the
variable face geometry created by this conventional forging process
may often exhibit waviness which will often need to be machined to
the exact precise geometry. U.S. Pat. No. 7,338,388 to Schweigert
et al. discusses this machining process by utilizing a ball end
mill revolving about an axis generally normal to the inner surface
of the face plate at an initial location on a circumferential
intersection between the outer edge of the central thickened region
and a transition region. The inner surface of the face plate is
machined by moving the revolving ball end mill in a radial
direction outwardly toward and through the transition region and
the peripheral region to machine the inner surface of the face
plate creating a tool channel having a width as the ball end mill
traverses the transition region and thereby vary the thickness of
the face plate in the tool path.
[0008] Although the machining process described above may be
capable of creating a very precise geometry, the resulting striking
face could still be flawed due to some inherent machining side
effects. Undesirable side effects such as the existence of machine
marks, circular cutting patterns, discontinuity of machine lines,
starting and stopping marks, and/or machine chatters could all
adversely affect the striking face.
[0009] U.S. Pat. No. 6,966,848 to Kusumoto attempts to address this
issue of trying to create an improved striking face of a golf club
head by disclosing a methodology wherein the stamped out face
material is placed in a die assembly, wherein the face material is
being thinned by causing the face material to plastically deform
via pressing an upper die together with the lower die. Although
this particular type of conventional forging methodology eliminates
the adverse side effects of machining above described, it suffers
from an entirely different set of adverse side effect. More
specifically, the conventional forging of a face insert suffers
from lack of material consistency and material transformation that
results when a material is melted and plastically deformed
resulting in grain growth and oxidation; both of which can lower
the material strength of a material.
[0010] In addition to the above flaws in the current manufacturing
techniques, these flaws of the current techniques become even more
apparent when a designer seeks to further advance the performance
of a striking face by implementing non-symmetrical geometries that
would either require extensive machining, or extreme sacrifice in
material property depending on the solution selected.
[0011] Hence, as it can be seen from above, despite all the
attempts in addressing the consistency and accuracy issue in
creating the variable thickness geometry in a golf club head, the
current art falls short in providing a methodology that can address
the issues above. Ultimately, it can be seen from above that there
is a need in the art for a methodology of creating portions of a
golf club head with variable thickness without relying on
conventional property changing forging techniques or simple
machining techniques to ensure more precision and consistency for
basic symmetrical geometries and even extreme asymmetrical
geometries.
BRIEF SUMMARY OF THE INVENTION
[0012] One non-limiting embodiment of the present technology
includes a method of forming a crown of a golf club head,
including: casting the crown of the golf club head, the crown of
the golf club head including an internal surface adjacent a hollow
interior of the golf club head, and an external surface opposite
the internal surface, the crown of the golf club head including a
first region and a second region adjacent the first region, the
second region substantially surrounding the first region, the first
region including a recess formed in the internal surface, the first
region including a sacrificial protrusion on the external surface
extending outwards beyond the second region, wherein the first
region of has an as-cast thickness T.sub.1, and thickness T.sub.1
is greater than or equal to 0.48 mm; applying a mask to the
external surface of the second region; exposing the crown of the
golf club head to an etching chemical, wherein the etching chemical
removes the sacrificial protrusion from the external surface of the
crown; removing the etching chemical from the crown of the golf
club head; and removing the mask from the second region.
[0013] One non-limiting embodiment of the present technology
includes a method of forming a portion of a golf club head,
including: casting the portion of the golf club head, the portion
of the golf club head including an internal surface adjacent a
hollow interior of the golf club head, and an external surface
opposite the internal surface, the portion of the golf club head
including a first region and a second region adjacent the first
region, the first region including a recess formed in the internal
surface, the first region including a sacrificial protrusion on the
external surface extending outwards beyond the second region;
applying a mask to the external surface of the second region;
exposing the portion of the golf club head to an etching chemical;
removing the etching chemical from the portion of the golf club
head; and removing the mask from the second region.
[0014] An additional non-limiting embodiment of the present
technology includes polishing the external surface of the portion
of the golf club head.
[0015] In an additional non-limiting embodiment of the present
technology the first region of has an as-cast thickness T.sub.1,
and thickness T.sub.1 is greater than or equal to 0.48 mm.
[0016] In an additional non-limiting embodiment of the present
technology the thickness T.sub.1 of the first region, after
exposing the portion of the golf club head to an etching chemical,
is reduced to less than or equal to 0.45 mm.
[0017] In an additional non-limiting embodiment of the present
technology the thickness T.sub.1 of the first region, after
exposing the portion of the golf club head to an etching chemical,
is reduced to less than or equal to 0.35 mm.
[0018] In an additional non-limiting embodiment of the present
technology the thickness T.sub.1 of the first region, after
exposing the portion of the golf club head to an etching chemical,
is reduced to less than or equal to 0.25 mm.
[0019] In an additional non-limiting embodiment of the present
technology exposing the portion of the golf club head to an etching
chemical removes the sacrificial protrusion from the first
region.
[0020] In an additional non-limiting embodiment of the present
technology exposing the portion of the golf club head to an etching
chemical is completed when the external surface is substantially
flush at the intersection of the first region and the second
region.
[0021] In an additional non-limiting embodiment of the present
technology the second region substantially surrounds the first
region.
[0022] In an additional non-limiting embodiment of the present
technology the second region has a thickness T.sub.2, and wherein
the recess has a depth D.sub.r, and wherein D.sub.r is greater than
or equal to T.sub.2/2.
[0023] One non-limiting embodiment of the present technology
includes a method of forming a crown of a golf club head,
including: casting the crown of the golf club head, the crown of
the golf club head including an internal surface adjacent a hollow
interior of the golf club head, and an external surface opposite
the internal surface, the crown of the golf club head including
first region and a second region adjacent the first region, the
first region including a recess formed in the internal surface, the
first region including a sacrificial protrusion on the external
surface extending outwards beyond the second region; applying a
mask to the external surface of the second region; exposing the
crown of the golf club head to an etching chemical, wherein the
etching chemical removes the sacrificial protrusion from the
external surface of the crown; removing the etching chemical from
the crown of the golf club head; and removing the mask from the
second region.
[0024] An additional non-limiting embodiment of the present
technology includes including polishing the external surface of the
crown of the golf club head.
[0025] In an additional non-limiting embodiment of the present
technology the first region of has an as-cast thickness T.sub.1,
and thickness T.sub.1 is greater than or equal to 0.48 mm.
[0026] In an additional non-limiting embodiment of the present
technology the thickness T.sub.1 of the first region, after
exposing the crown of the golf club head to an etching chemical, is
reduced to less than or equal to 0.45 mm.
[0027] In an additional non-limiting embodiment of the present
technology the thickness T.sub.1 of the first region after exposing
the crown of the golf club head to an etching chemical is reduced
to less than or equal to 0.35 mm.
[0028] In an additional non-limiting embodiment of the present
technology the thickness T.sub.1 of the first region after exposing
the crown of the golf club head to an etching chemical is reduced
to less than or equal to 0.25 mm.
[0029] In an additional non-limiting embodiment of the present
technology exposing the crown of the golf club head to an etching
chemical is completed when the external surface is substantially
flush at the intersection of the first region and the second
region.
[0030] In an additional non-limiting embodiment of the present
technology the second region substantially surrounds the first
region.
[0031] In an additional non-limiting embodiment of the present
technology the second region has a thickness T.sub.2, and wherein
the recess has a depth D.sub.r, and wherein D.sub.r is greater than
or equal to T.sub.2/2.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The foregoing and other features and advantages of the
invention will be apparent from the following description of the
invention as illustrated in the accompanying drawings. The
accompanying drawings, which are incorporated herein and form a
part of the specification, further serve to explain the principles
of the invention and to enable a person skilled in the pertinent
art to make and use the invention.
[0033] FIG. 1 shows a perspective view of a golf club head that is
disassembled.
[0034] FIG. 2 shows an internal rear view of a face insert.
[0035] FIG. 3 shows a cross-sectional view of a face insert.
[0036] FIG. 4a shows a side view of one of the steps used to create
a face insert.
[0037] FIG. 4b shows a side view of one of the steps used to create
a face insert.
[0038] FIG. 4c shows a side view of one of the steps used to create
a face insert.
[0039] FIG. 5a shows a side view of one of the steps used to create
a face insert.
[0040] FIG. 5b shows a side view of one of the steps used to create
a face insert.
[0041] FIG. 5c shows a side view of one of the steps used to create
a face insert.
[0042] FIG. 6a shows a cross-sectional view of a face insert.
[0043] FIG. 6b shows a cross-sectional view of a face insert.
[0044] FIG. 7 shows a perspective view of one embodiment a golf
club head including a striking face, a crown, a sole, and a
hosel.
[0045] FIG. 8 shows a front elevation view of the golf club head of
FIG. 7.
[0046] FIG. 9 shows a top view of the external surface of one
embodiment of a crown of a golf club head.
[0047] FIG. 10 shows a bottom view of the internal surface of the
crown of FIG. 9.
[0048] FIG. 11 shows a cross-sectional view of the crown of FIG. 9
taken across cross-sectional line C-C' as shown in FIGS. 9 and
10.
[0049] FIG. 12 shows one embodiment of a crown of a golf club head
including heel toe ribs.
[0050] FIG. 13 shows one embodiment of a crown of a golf club head
including a criss-cross rib pattern.
[0051] FIG. 14A shows a cross sectional view of the first step of
the stamped forging process wherein the crown is placed between a
top punch and a bottom cavity configured to deform the crown.
[0052] FIG. 14B shows a cross sectional view of the next step of
the stamped forging process wherein the top punch compresses
towards the bottom cavity to alter the shape and geometry of the
crown.
[0053] FIG. 14C shows the next step of the stamped forging process
wherein the top punch is retracted away from the bottom cavity and
off of the crown.
[0054] FIG. 15A shows a cutter about to remove excess material from
the crown and the cutting line.
[0055] FIG. 15B shows an intermediary stage of the cutting process
wherein the cutter begins to remove excess material from the crown
along the cutting line.
[0056] FIG. 15C shows the crown wherein the excess material has
been removed by the cutter.
[0057] FIG. 16A shows the crown positioned between an external die
and an internal die.
[0058] FIG. 16B shows the crown after being bent to the desired
curvature by the internal die and external die.
[0059] FIG. 17A shows a cross sectional view of a deformed crown
between a curved top punch and a curved bottom cavity.
[0060] FIG. 17B shows a cross sectional view of the crown being
machined by the cutter.
[0061] FIG. 17C shows a cross sectional view of the crown after
being machined by the cutter.
[0062] FIG. 18 illustrates a perspective view of a golf club head
1000 including a striking face 1100, a crown 1200, a sole 1300, and
a hosel 1400.
[0063] FIG. 19 illustrates a perspective view of the golf club head
1000 of FIG. 18, including a thin region 1230 located in the crown
1200.
[0064] FIG. 20 illustrates a cross-sectional view of the crown 1200
of FIG. 19.
[0065] FIG. 21A illustrates a cross-sectional view of the crown
after casting.
[0066] FIG. 21B illustrates a cross-sectional view of the crown
after masking.
[0067] FIG. 21C illustrates a cross-sectional view of the crown
during etching.
[0068] FIG. 21D illustrates a cross-sectional view of the crown
after removing the masking.
[0069] FIG. 22 illustrates the method of creating variable
thickness geometries in golf club heads.
DETAILED DESCRIPTION OF THE INVENTION
[0070] The following detailed description describes the best
currently contemplated modes of carrying out the invention. The
description is not to be taken in a limiting sense, but is made
merely for the purpose of illustrating the general principles of
the invention, since the scope of the invention is best defined by
the appended claims.
[0071] Various inventive features are described below and each can
be used independently of one another or in combination with other
features. However, any single inventive feature may not address any
or all of the problems discussed above or may only address one of
the problems discussed above. Further, one or more of the problems
discussed above may not be fully addressed by any of the features
described below.
[0072] FIG. 1 of the accompanying drawings shows a perspective view
of a golf club head 100 wherein a body portion 102 and a face
insert 104 are disassembled to show the variable face thickness at
a rear portion of the face insert 104. It should be noted in FIG. 1
the golf club head has the face insert 104 forming the striking
face portion of the golf club head 100 as one of the exemplary
embodiments. However, a face insert 104 type geometry is not the
only way to form the striking face portion, in fact numerous other
geometries can be used to form the striking face portion such as a
C shaped face cup, a L shaped face cup, a T shaped face cup, or any
other suitable geometry all without departing from the scope and
content of the present invention.
[0073] FIG. 2 of the accompanying drawings shows a more detailed
enlarged perspective view of a face insert 204 in accordance with
an exemplary embodiment of the present invention. More
specifically, the internal back view of the face insert 204 allows
the face center 210, central region 212, transition region 214, and
the perimeter region 216 to all be easily shown. In addition to
showing the various regions, FIG. 2 of the accompanying drawings
shows a cross-sectional line A-A' horizontally dividing the face
insert 204 to illustrate the relative thicknesses of the various
regions in FIG. 3. This cross-sectional line A-A' may also be known
as the horizontal dividing line, spanning horizontally through the
heel and toe portion of said face insert passing through a face
center 210. FIG. 2 also shows a vertical dividing line B-B', that
spans vertically through the crown and sole portion of said face
insert passing through a face center 210.
[0074] FIG. 3 of the accompanying drawings shows a cross-sectional
view of the face insert 304 taken across cross-sectional line A-A'
as shown in FIG. 2. It should be noted that FIG. 3 of the present
invention shows a central region 312 having a first thickness d1, a
first transition region 314 having a second thickness d2, a first
perimeter region 316 having a third thickness d3, a second
transition region 313 having a fourth thickness d4, and a second
perimeter region 315 having a fifth thickness d5. In one exemplary
embodiment, wherein the geometry of the variable face thickness is
symmetrical, the thickness of the first and second transition
regions 313 and 314 are the same and the thickness of the first and
second perimeter region 315 and 316 are the same. It should be
noted that due to the fact that the transition regions 313 and 314
are constantly transitioning in thickness from the central region
312 to the perimeter regions 315 and 316, the thickness of the
transition regions 313 and 314 are measured at the center of the
transition regions 313 and 314. In some instances it is preferred
to have symmetry in the variable face thickness geometry, as it
makes for fairly simple and straight forward machining. However,
the symmetrical geometry may not truly optimize the weight and
performance characteristics of a striking face, and has generally
stemmed from the machining problems that can come with asymmetrical
geometries.
[0075] Hence, in accordance with an alternative and preferred
embodiment of the present invention, the face insert 304 may have
an asymmetrical geometry. More specifically, the first transition
region 314 may have a second thickness d2 that is different from
the fourth thickness d4 of the second transition region 313, and
the first perimeter region 316 may have a third thickness d3 that
is different from the fifth thickness d5 of the second perimeter
region 315. Removing the restriction of symmetrical variable face
thickness geometry removes unnecessary design restrictions to allow
a golf club designer to truly optimize the face design. In fact,
the preference for symmetrical face geometries in a face insert has
always been driven by manufacturing preferences. In one exemplary
embodiment, a golf club designer could further thin out different
regions of the striking face that is not subjected to the highest
level of stress, creating more discretionary mass to be moved to
different regions of the golf club head itself.
[0076] In this exemplary embodiment, thickness d1 of the central
region 312 may generally be greater than about 3.0 mm, more
preferably greater than about 3.30 mm, and most preferably greater
than about 3.60 mm. Thickness d2 and d4 of the transition regions
314 and 313 respectively may generally decrease from about 3.60 mm
to about 2.7 mm, more preferably from about 3.60 mm to about 2.65
mm, and most preferably from about 3.60 mm to about 2.60 mm.
Finally, thickness d3 and d5 of perimeter regions 316 and 315
respectively may generally also be decreasing from about 2.70 mm to
about 2.55 mm, more preferably from about 2.65 mm to about 2.50 mm,
and most preferably from about 2.60 mm to about 2.45 mm.
[0077] Based on the above, it can be seen that a new methodology
needs to be created to effectively create this constantly changing
face thickness without the need to machine complicated geometry
that is asymmetrical. The current invention, in order to achieve
this goal has created an innovative machining process detailed in
FIGS. 4a, 4b, 4c, 5a, 5b, and 5c shown in the later figures.
[0078] FIG. 4a through FIG. 4c illustrates graphical depiction of
the new innovative face insert forming technique associated with an
exemplary embodiment of the present invention called "stamped
forging". Although this new innovative forming technique may have
some similarities to the conventional forging process, it is
completely different. In fact, the conventional forging process
involves deformation of the face insert 404 pre-form material to
create the material flow into a cavity. This melting of the
material is undesirable when used to form the striking face portion
of the golf club head, as the melting of the material, combined
with the phase transformation of the material, could result in
grain growth and oxidation of the titanium material, both of which
diminishes the material strength of titanium.
[0079] The current process is completely different from the
conventional forging process because it involves the elements of
stamping as well as forging, and can be more accurately described
as "stamped forging" or "embossed forging". During this "stamped
forging" or "embossed forging" process the face-insert 404 pre-form
does not experience any phase transformation, but is merely warmed
to a malleable temperature to allow deformation without the actual
melting of the face insert 404 pre-form.
[0080] More specifically, in FIG. 4a, a side view of the first step
in the current forming technique is shown. In FIG. 4a, the various
components used for the formation of the face insert 404 such as
the top punch 421 and bottom cavity 422 are shown in more detail.
More specifically, as it can be seen from FIG. 4a, the top punch
421 has a protrusion 424 created in roughly the shape of the
desired variable face thickness geometry; while the bottom cavity
422 has a corresponding depression 426 that also roughly
corresponds to the shape of the desired variable face thickness
geometry. Although not shown in extreme detail, FIG. 4a shows that
the bottom cavity 422 could be non-linear along the perimeter edges
427 to create a constantly variable thickness across the entire
perimeter surface of the face insert 404 pre-form.
[0081] FIG. 4b shows the next step of the current inventive stamped
forging methodology wherein the top punch 421 compresses against
the bottom cavity 422 to alter the shape and geometry of the face
insert 404. Although the current inventive methodology does not
involve the melting of the material used to create the face insert
404, the face insert 404 is generally heated up to about
830.degree. C. for about 300 seconds on a conveyor belt to increase
the malleability of the face insert 404 to allow for the
deformation. In this current exemplary embodiment of the invention
the top punch 421 generally applies about 100 MPa of pressure onto
the face insert 404 for about 2 seconds to create the desired
geometry.
[0082] FIG. 4c shows the next step of the current inventive stamped
forging methodology wherein the shape of the variable face
thickness geometry begins to take place when the top punch 421 is
removed from the bottom cavity 422. It should be noted here that in
this current exemplary embodiment of the present invention, the
side of the face insert 404 that faces the top punch 421 will
eventually form the external surface of the face insert 404 as it
gets assembled in the golf club head, while the side of the face
insert 404 that contacts the bottom cavity 422 will eventually form
the internal surface of the face insert 404 as it gets assembled in
the golf club head. This type of methodology ensures that a precise
geometry could be achieved on the internal side of the face insert
404 without the need for excessive machining, even if a
non-symmetrical organic shape is desired to maximize the
performance of the face insert 404.
[0083] Although the steps described above in FIGS. 4a through 4c
may be sufficient to create the desired geometry in some
circumstances, additional steps similar to the ones described above
may be repeated to achieve more precise and complicated geometries.
In the alternative embodiments wherein multiple stamped forging
steps are required, the process could be repeated for rough and
fine stamped forging without departing from the scope and content
of the present invention. In fact, the steps described could be
repeated three time, four times, or any number of times necessary
to achieve the desired geometry all without departing from the
scope and content of the present invention. In cases wherein
multiple stamped forging steps are needed, the shape and geometry
of the top punch 421 and the bottom cavity 422 may even be slightly
different from one another, with each finer mold having a closer
resemblance to the final finished geometry.
[0084] Once the geometry of the internal surface of the face insert
404 is formed via the above prescribed methodology, the external
surface of the face insert 404 can be machined off a flat geometry,
which is a significant improvement than the conventional
methodology of actually machining in the complicated geometry on
the rear internal surface of the face insert 404. FIGS. 5a through
5c illustrate the final steps involved in machining off the excess
material in this the current face insert 504 stamped forging
methodology.
[0085] FIGS. 5a-5c show side views of a face insert 504 together
with the bottom cavity 522 after the top punch (not shown) has
created the desired geometry by deforming the shape of the face
insert 504 in the previous steps. In these final steps, the excess
material of the face insert 504 is removed via a cutter 530. The
excess material, as shown in this current exemplary embodiment of
the present invention, may generally be defined as any material
that is above the cutting line 531 shown in FIG. 5a. This cutting
line 531 is generally defined by the flat surface that
significantly aligns with the bottom of the rear indentation 528 of
the formed face insert 504. In fact, in most exemplary embodiments,
the cutting line 531 may actually be placed slightly below the
bottom of the rear indentation 528 of the formed face insert 504 to
allow for a precise finish of the face insert 504.
[0086] The position of this cutting line 531 can be important, as
it determines the relative thickness of the face insert 504. Hence,
in order to more accurately define this cutting line 531, distance
d6 and d7 are identified in FIG. 5a. Here, in this current
exemplary embodiment distance d6 signifies the distance of the
final thickness of the perimeter relative to the perimeter surface
of the bottom cavity 522. This distance d6 may generally vary from
about 2.2 mm to about 2.6 mm, more preferably from about 2.3 mm to
about 2.6 mm, and most preferably from about 2.4 mm to about 2.6
mm. However, as it has already been discussed before the perimeter
region of the face insert 504 could very well have a variable
thickness, thus making it difficult to determine the thickness of
d6; as the thickness d6 would be a function of the perimeter of the
face insert 504. Thus, in order to properly index the cutter 530 to
remove the correct amount of material from the frontal surface of
the striking face 504, an additional thickness d7 is identified;
measuring the distance from the bottom of the depression 526 of the
bottom cavity 522 to the cutting line 531 from which the removal of
material is indexed. Distance d7, as it is shown in this current
exemplary embodiment of the present invention, may generally be
between about 3.5 mm to about 3.8 mm, more preferably between about
3.6 mm to about 3.7 mm, and most preferably about 3.65 mm.
[0087] The cutter 530 shown in this current exemplary embodiment of
the present invention may generally be a fly cutter type cutter to
ensure a smooth surface that will eventually form the frontal
surface of a golf club head, however, numerous other types of
cutters may be used without departing from the scope and content of
the present invention. More specifically, alternative cutters 530
may include an end mill clutter, a ball nose cutter, a side and
face cutter, a woodruff cutter, a shell mill cutter, or any type of
milling cutter all without departing from the scope and content of
the present invention. In fact, the finished surface could even
potentially be achieved by any alternative finishing techniques
that could create a flat surface all without departing from the
scope and content of the present invention.
[0088] FIG. 5b shows an intermediary stage of the cutting process
wherein the cutter 530 begins to remove excess material from the
formed face insert 504 along cutting line 531. Finally, FIG. 5c
shows the finished product of a face insert 504 in accordance with
an exemplary embodiment of the present invention wherein the excess
material has been removed by the cutter 530. The finished face
insert 504 can then be bent to the required curvature to match the
bulge and roll of a golf club head and installed to complete the
golf club head. As it can be seen from above, the innovative
forming and finishing method is a major improvement in simplifying
the machining process involved to a simple one pass finish,
especially when compared to the conventional method of machining
the actual variable thickness geometry. This advantage of not
having to machine the actual geometry becomes even more apparent
when the variable geometry implemented involves non-symmetrical
shapes, as those types of geometries become extremely difficult to
machine using conventional machining methods.
[0089] FIGS. 6a and 6b show alternative embodiments of the present
invention wherein the frontal indentation 628 of the striking face
insert 622 are preserved and not machined off. In these
embodiments, the frontal indentation 628 could be filled with a
secondary material that is different from the material used to
create the face insert 622 to create a striking face insert 622
that incorporates multiple materials. The filler 630 in this
current exemplary embodiment could be made out of steel, aluminum,
tungsten, composites, or any other types of material that can be
reasonably adhered to the rear indentation 628 of the face insert
622 without departing from the scope and content of the present
invention. The filler 630 material may have a have a second density
greater than a density of the material used to create the face
insert 622 in one exemplary embodiment of the present invention;
however, in an alternative embodiment of the present invention, the
filler 630 material may also have a second density that is less
than the density of the material used to create the face insert 622
without departing from the scope and content of the present
invention. In an alternative embodiment, the frontal indentation
628 could be filled with a filler 630 that is made out of a similar
type material as the remainder of the face insert 622 to ensure
sufficient bonding and cohesion between the materials. More
specifically, in this alternative embodiment, the filler 630
material could be Ti-64, Ti-811, SP-700, ATI-425, or any other type
of titanium alloys all without departing from the scope and content
of the present invention.
[0090] FIG. 6b shows a further alternative embodiment of the
present invention wherein the external surface of the face insert
622 could be covered with a cover layer 632 to ensure that the
entire external surface of the face insert 622 has the same
material to conform with the requirements of the USGA. In one
exemplary embodiment of the present invention the cover layer 632
may be made out of titanium type material similar to the remainder
of the body; however, different types of titanium alloys could be
used without departing from the scope and content of the present
invention as long as it is capable of covering the external surface
of the face insert 622.
[0091] In additional embodiments, the characteristics and methods
illustrated and described herein can be applied to other portions
of the golf club head which may include for example, the sole, the
crown, etc. Each step of the "stamped forging" process described
above in reference to the face insert or the striking face can be
applied to another portion of the golf club head which may include,
for example, the sole, the crown, etc.
[0092] FIG. 7 of the accompanying drawings shows a perspective view
of a golf club head 1000 including a striking face 1100, a crown
1200, a sole 1300, and a hosel 1400. The golf club head 1000
includes a forward portion 1500 including the striking face 1100
and an aft portion 1600 opposite the striking face 1100. FIG. 8 of
the accompanying drawings shows a front elevation view of the golf
club head 1000 of FIG. 7. The golf club head 1000 includes a heel
portion 1700 adjacent the hosel 1400 and a toe portion 1800
opposite the heel portion 1700. In some embodiments, the golf club
head 1000 can comprise a face insert construction. In additional
embodiments, the golf club head 1000 can comprise other
constructions which may include for example, a C shaped face cup,
an L shaped face cup, a T shaped face cup, or any other suitable
geometry all without departing from the scope and content of the
present invention.
[0093] In some embodiments, various portions of the golf club head
1000 such as the striking face 1100, crown 1200, and sole 1300 can
be formed separately and adjoined to form the golf club head 1000.
It can be advantageous to vary the thickness of the different
portions to reduce weight, reduce stress, alter the performance of
the golf club head 1000, and even to alter the acoustic
characteristics of the golf club head 1000. FIGS. 9-16 illustrate
various embodiments and methods of construction of the crown
portion 1200 of a golf club head 1000. In additional embodiments,
the characteristics and methods illustrated and described herein
can be applied to other portions of the golf club head 1000 which
may include for example, the sole 1300, the striking face 1100,
etc.
[0094] FIG. 9 of the accompanying drawings shows a top view of the
external surface 1210 of one embodiment of a crown 1200. In some
embodiments, including the one illustrated in FIG. 9, the external
surface 1210 of the crown 1200 can be smooth to create a clean
appearance when viewing the golf club head from the address
position. FIG. 9 of the accompanying drawings shows a
cross-sectional line C-C' dividing the crown 1200 to show the
relative thicknesses of the various regions in FIG. 11. This
cross-sectional line C-C' may also be known as a crown dividing
line, spanning horizontally through the heel 1700 and toe portion
1800 of the crown 1200 and providing a view from the forward
portion 1500 looking toward the aft portion 1600 of the crown 1200.
FIG. 10 of the accompanying drawings shows a bottom view of the
internal surface 1220 of the crown 1200 of FIG. 9. FIG. 10 also
shows a cross-sectional line C-C' dividing the crown 1200 to show
the relative thicknesses of the various regions in FIG. 11
[0095] FIG. 11 of the accompanying drawings shows a cross-sectional
view of the crown 1200 taken across cross-sectional line C-C' as
shown in FIGS. 9 and 10. In some embodiments the crown 1200 can
include variable thickness. The crown 1200 can include at least one
thick region 1240 and at least one thin region 1230. In some
embodiments, as illustrated in FIGS. 10 and 11, the crown 1200 can
include a plurality of thin regions 1230 with a thickness D8 and a
plurality of thick regions 1240 with a thickness D9. The
thicknesses D8 of the thin regions 1230 is measured at the center
of the thin regions 1230 and the thickness D9 of the thick regions
1240 is measured at the center of the thick regions 1240. The
thickness in the transition regions between the thick regions 1240
and thin regions 1230 can vary between the thickness D9 of the
thick region 1240 and the thickness D8 of the thin region 1230. In
some embodiments, the transition regions between the thick regions
1240 and thin regions 13230 can comprise a taper or a curve. In
additional embodiments, the crown 1200 can include additional
regions with thicknesses different than the thin regions 1230 and
thick regions 1240. In some embodiments, the thickness of the thin
region 1230 can be thicker in the forward portion 1500 and thinner
in the aft portion 1600.
[0096] In some embodiments, the thickness D8 of the thin regions
1230 can generally be between 0.1 mm and 1.0 mm. In some
embodiments, the thickness D8 of the thin regions 1230 can
generally be between 0.2 mm and 0.5 mm. In some embodiments, the
thickness D8 of the thin regions 1230 can generally be between 0.3
mm and 0.4 mm. In some embodiments, the thickness D8 of the thin
regions 1230 can generally be between 0.325 mm and 0.375 mm. In
some embodiments, the thickness D8 of the thin regions 1230 can
generally be between 0.340 mm and 0.360 mm. In some embodiments,
the thickness D9 of the thick regions 1240 can generally be between
0.1 mm and 1.0 mm. In some embodiments, the thickness D9 of the
thick regions 1240 can generally be between 0.2 mm and 0.8 mm. In
some embodiments, the thickness D9 of the thick regions 1240 can
generally be between 0.3 mm and 0.7 mm. In some embodiments, the
thickness D9 of the thick regions 1240 can generally be between 0.4
mm and 0.6 mm. In some embodiments, the thickness D9 of the thick
regions 1240 can generally be between 0.45 mm and 0.55 mm. In some
embodiments, the thickness D9 of the thick regions 1240 can
generally be between 0.48 mm and 0.52 mm. In some embodiments, the
thickness D9 of the thick regions 1240 can generally be between
0.49 mm and 0.51 mm.
[0097] The geometry and orientation of the thick regions 1240 and
thin regions 1230 can include ribs 1250 extending away from the
thin region 1230. In some embodiments, the thick regions 1240 can
comprise for example, forward aft ribs 1250 as illustrated in FIGS.
10 and 11. As illustrated in FIG. 11, the ribs 1250 can comprise a
protrusion extending into the interior of the golf club head 1000
from the internal surface 1220 of the crown 1200. The ribs 1250 can
add structural support to the crown 1200 and the thin regions 1230
can minimize the weight of the crown 1200, providing a golf club
manufacturer with the ability to place weight elsewhere in the golf
club head 1000 to maximize performance. The thickness D9 of the
thick region 1240 comprises both the thickness D8 of the thin
region 1230 in addition to the distance the thick region 1240
protrudes away from the inner surface 1220 of the thin region 1230.
In some embodiments, the plurality of thick regions 1240 may share
the same thickness D9. In some embodiments, the plurality of thin
regions 1230 may share the same thickness D8.
[0098] In additional embodiments, the thickness of various thick
regions 1240 or thin regions 1230 may vary in order to optimize the
performance of the golf club head 1000. In some embodiments, at
least one of the plurality of thick regions 1240 can comprise a
different thickness than another thick region 1240. In some
embodiments, at least one of the plurality of thin regions 1230 can
comprise a different thickness than another thin region 1230. In
some embodiments, the thickness of at least one thick region 1240
or thin region 1230 may vary along its length. In some embodiments,
at least one thick region 1240 can be thicker near the forward
portion 1500 of the golf club head 1000 and thinner near the aft
portion 1600 of the golf club head. In some embodiments, at least
one thick region 1240 can be thicker near the forward portion 1500
and the aft portion 1600 of the golf club head of the golf club
head 1000 and thinner in portion between the forward portion 1500
and aft portion 1600. In some embodiments, at least one thin region
1230 can be thicker near the forward portion 1500 of the golf club
head 1000 and thinner near the aft portion 1600 of the golf club
head. In some embodiments, at least one thin region 1230 can be
thicker near the forward portion 1500 and the aft portion 1600 of
the golf club head of the golf club head 1000 and thinner in
portion between the forward portion 1500 and aft portion 1600. In
other embodiments, the thickness of the thick regions 1240 and thin
regions 1230 can vary from the heel side of the golf club head 1000
to the toe side.
[0099] In additional embodiments, the thick regions 1240 and thin
regions 1230 can include additional geometries and orientations,
which may include for example, the heel toe ribs 1250 as
illustrated in FIG. 12 or the criss-cross rib 1250 pattern as
illustrated in FIG. 13. In additional embodiments (not
illustrated), thick regions 1240 can extend outward from the
external surface 1210 of the crown 1200. In additional embodiments
(not illustrated), the thick regions 1240 can both extend inward
into the interior of the golf club head 1000 from the internal
surface 1220 of the crown 1200 and outwards from the external
surface 1210 of the crown 1200.
[0100] Machining the geometries described herein can be difficult
and cost prohibitive. In some embodiments, the geometries described
herein can be constructed utilizing an innovative process called
"stamped forging" detailed in FIGS. 14A-C, 15A-C, 16A-B and
described herein. During the "stamped forging" process the crown
1200 does not experience any phase transformation, but is merely
warmed to a malleable temperature to allow deformation without the
actual melting of the crown 1200.
[0101] FIG. 14A shows a cross sectional view of the first step of
the stamped forging process wherein the crown 1200 is placed
between a top punch 2000 and a bottom cavity 3000 configured to
deform the crown 1200. The top punch 2000 can comprise a plurality
of protrusions 2100 arranged to reflect the pattern of thick
regions 1240 in the crown 1200. The bottom cavity 3000 can comprise
a corresponding plurality of depressions 3100 which also reflects
the pattern of thick regions 1240 in the crown 1200. Although not
illustrated, in some embodiments, the top punch engagement surface
2200 or the bottom cavity engagement surface 3200 can vary in depth
to vary the thickness among the thin regions 1230 of the crown
1200. In addition, in some embodiments, the depth of the
protrusions 2100 in the top punch 2000 and depressions 3100 in the
bottom cavity 3000 can vary to create a variable thickness among
the plurality of thick regions 1240 of the crown 1200.
[0102] FIG. 14B shows a cross sectional view of the next step of
the stamped forging process wherein the top punch 2000 compresses
towards the bottom cavity 3000 to alter the shape and geometry of
the crown 1200. In some embodiments, the crown 1200 can be heated
to about 830.degree. C. for about 300 seconds to increase the
malleability of the crown 1200 to allow for deformation. In some
embodiments, the top punch 2000 generally applies about 100 MPa of
pressure onto the crown 1200 for about 2 seconds to create the
desired geometry. In other embodiments, the crown 1200 can be
heated to about 1080.degree. C. for about 300 seconds to increase
the malleability of the crown 1200 to allow for deformation. In
additional embodiments, the crown can be heated to a temperature
between about 700.degree. C. and 1300.degree. C. In another
embodiment, the crown can be heated to a temperature between about
750.degree. C. and 900.degree. C. In another embodiment, the crown
can be heated to a temperature between about 800.degree. C. and
850.degree. C. In another embodiment, the crown can be heated to a
temperature between about 1000.degree. C. and 1200.degree. C. In
another embodiment, the crown can be heated to a temperature
between about 1050.degree. C. and 1100.degree. C.
[0103] FIG. 14C shows the next step of the stamped forging process
wherein the top punch 2000 is retracted away from the bottom cavity
3000 and off of the crown 1200. In some embodiments, the portion of
the crown 1200 facing the top punch 2000 will eventually become the
external surface 1210 of the crown 1200 while the portion of the
crown 1200 facing the bottom cavity 3000 will eventually become be
the internal surface 1220 of the crown 1200. This process ensures
that a precise geometry can be achieved on the internal surface
1220 of the crown 1200 without the need for excessive machining. In
other embodiments, not illustrated, the opposite may be true and
the portion of the crown facing the top punch 2000 will eventually
become the internal surface 1220 of the crown 1200 while the
portion of the crown 1200 facing the bottom cavity 3000 will
eventually become be the external surface 1210 of the crown
1200.
[0104] Although the steps described above in FIGS. 14A-14C may be
sufficient to create the desired geometry in some circumstances,
additional steps similar to the ones described above may be
repeated to achieve more precise and complicated geometries. In the
alternative embodiments wherein multiple stamped forging steps are
required, the process could be repeated for rough and fine stamped
forging without departing from the scope and content of the present
invention. In fact, the steps described could be repeated three
time, four times, or any number of times necessary to achieve the
desired geometry all without departing from the scope and content
of the present invention. In cases wherein multiple stamped forging
steps are needed, the shape and geometry of the top punch 2000 and
the bottom cavity 3000 may even be slightly different from one
another, with each finer mold having a closer resemblance to the
final finished geometry.
[0105] Once the geometry of the internal surface 1220 of the crown
is formed via the above prescribed methodology, the external
surface 1210 of the crown can be machined flat. Machining the
external surface 1210 flat can be more cost effective then
machining the geometry into the internal surface 1220 of the crown
1200. FIGS. 15A-15C illustrated the steps involved in machining off
the excess material of the crown 1200. FIGS. 15A-15C show side
views of a crown 1200 together with the bottom cavity 3000 after
the top punch (not shown) has created the desired geometry by
deforming the shape of the crown 1200 in the previous steps. As
illustrated in FIGS. 15A-15C, the excess material of the crown 1200
is removed via a cutter 4000. The excess material, as shown in the
embodiment illustrated in FIG. 15A, is generally defined as any
material that is above the cutting line 4100. In some embodiments,
the cutting line 4100 can be located along a flat surface that
significantly aligns with the bottom of the indentations 1260
formed in the crown 1200. In most embodiments, the cutting line
4100 can be offset slightly below the bottom of the indentations
1260 of the crown 1200 to allow for a precise finish of the
external surface 1210 of the crown 1200.
[0106] The position of the cutting line 4100 can be important, as
it determines the thickness D8 of the thin region 1230. In order to
more accurately define the cutting line 4100, the distance D10 is
identified in FIG. 15A. The distance D10 signifies the distance
between the bottom cavity engagement surface 3200 and the cutting
line 4100. In some embodiments, the distance D10 mirrors the
thickness D8 of the thin region 1230 of the crown 1200. However, in
some embodiments, the thin region 1230 of the crown 1200 could have
a variable thickness, making it difficult to determine the
thickness D8 of the crown 1200 and the height of the cutting line
4100 from the bottom cavity engagement surface 3200. The distance
D10 may not be consistent across the cross section of the crown
1200 if the bottom cavity engagement surface 3200 is not flat. In
such embodiments, the corresponding thickness D8 of the thin region
1230 may vary across the crown 1200. Thus, a distance D11 is
identified in FIG. 15A, which represents the distance from the
bottom of the depressions 3100 of the bottom cavity to the cutting
line 4100. In some embodiments, the distance D11 mirrors the
thickness D9 of the thick region 1240 of the crown 1200.
[0107] The cutter 4000 may generally be a fly cutter type cutter to
ensure a smooth surface that will eventually form the external
surface 1210 of the crown 1200, however, numerous other types of
cutters 4000 may be used without departing from the scope and
content of the present invention. More specifically, alternative
cutters 4000 may include an end mill clutter, a ball nose cutter, a
side cutter, face cutter, a woodruff cutter, a shell mill cutter,
or any type of milling cutter all without departing from the scope
and content of the present invention. In fact, the finished surface
could even potentially be achieved by any alternative finishing
techniques, which may include, for example, polishing, that could
create a flat surface all without departing from the scope and
content of the present invention.
[0108] FIG. 15B shows an intermediary stage of the cutting process
wherein the cutter 4000 begins to remove excess material from the
crown 1200 along cutting line 4100. Finally, FIG. 15C shows the
crown 1200 in accordance with an exemplary embodiment of the
present invention wherein the excess material has been removed by
the cutter 4000. The crown 1200 can then be bent as illustrated in
FIGS. 16A and 16B to the required curvature. The crown 1200 can be
removed from the bottom cavity 3000 and positioned between an
external die 5000 and an internal die 6000 as illustrated in FIG.
16A. The external die 5000 can comprise a concave engagement
surface 5100 configured to engage the external surface 1210 of the
crown 1200. The internal die 6000 can comprise a convex engagement
surface 6100 configured to engage the internal surface 1220 of the
crown 1200. The external die 5000 can be forced towards the
internal die 6000, curving the crown 1200 to the desired geometry
as illustrated in FIG. 16B. In some embodiments, not illustrated,
the internal die 6000 can comprise depressions similar to the
bottom cavity 3000 described earlier to receive the ribs 1250 of
the crown 1200. As it can be seen from above, the innovative
forming and finishing method is a major improvement in simplifying
the machining process involved to a simple one pass finish,
especially when compared to the alternatives of machining the
actual variable thickness geometry or masking off the geometry and
utilizing chemical etching techniques.
[0109] In another embodiment, the steps of the stamped forging
process described in reference to FIGS. 14A-14C and 16A-16C can be
completed simultaneously. FIG. 17A shows a cross sectional view of
a deformed crown 1200 between a curved top punch 7000 and a curved
bottom cavity 8000. The top punch 7000 can be curved, much like the
curved external die 5000 illustrated in FIGS. 16A-B, and the
engagement surface 7200 comprise a plurality of protrusions 7100
arranged to reflect the pattern of thick regions 1240 in the crown
1200. The bottom cavity 8000 can be curved, much like the curved
internal die 6000 illustrated in FIGS. 16A-B, and the engagement
surface 8200 can comprise a corresponding plurality of depressions
8100 which also reflect the pattern of thick regions 1240 in the
crown 1200. After the crown is deformed by the curved top punch
7000 and curved bottom cavity 8000, excess material can be machined
off the crown. FIG. 17B shows a cross sectional view of the crown
1200 being machined by the cutter 4000. FIG. 17C shows a cross
sectional view of the crown 1200 after being machined by the cutter
4000. In some embodiments, as illustrated in FIG. 17B, the crown
1200 can remain positioned on the curved bottom cavity 8000 during
the machining. In some embodiments, rather than machining a flat
surface as described in relation to FIGS. 15A-15C, the cutter 4000
will machine excess material off the crown 1200 to create a curved
external surface 1210, as illustrated in FIGS. 17B and 17C, while
leaving the ribs 1250 on the internal surface 1220 of the
crown.
[0110] In additional embodiments, the characteristics and methods
illustrated and described herein can be applied to other portions
of the golf club head which may include for example, the sole, the
striking face, etc. Each step of the "stamped forging" process
described above in reference to the crown or the striking face can
be applied to another portion of the golf club head which may
include, for example, the sole, the striking face, the crown, etc.
The "stamped forging" methods described herein are particularly
useful for imparting a variable thickness geometry to a portion of
a golf club head, particularly one in which the external surface is
desired to have a smooth surface and the inside surface desirably
includes thick regions of a particular geometry to alter the
performance characteristics of the golf club head. Additional
thickness variations and geometries of various portions of the golf
club head are possible utilizing the methods described herein. For
example, the process could be modified such that the variable
thickness geometry is exposed on the exterior surface of the golf
club head rather than the interior as illustrated and described
herein. In addition, the methods described herein can be applied to
irons and putters in addition the metal wood clubs illustrated in
the Figures. The face of an iron type golf club, for example, could
be formed utilizing the stamped forging methods described herein
and then welded or bonded to the body of the golf club head.
[0111] FIG. 18 illustrates a perspective view of a golf club head
1000 including a striking face 1100, a crown 1200, a sole 1300, and
a hosel 1400. The striking face and crowns described earlier were
created using a stamped forging process. In some embodiments, it
can be advantageous and more cost effective to create portions of
the golf club head 1000 via casting. For illustrative purposes, we
will assume the golf club head 1000 is a face-pull cast
construction, which means the body portion 1610, the majority of
the golf club head 1000, is cast and the casting tooling is pulled
through a window in the striking face 1100 of the golf club head
1000. Once the body portion 1610 of the golf club head 1000 is cast
then a face insert 1110 is welded to the golf club head 1000,
filling the window. Other castable constructions are possible and
compatible with the construction techniques described herein. Most
golf club heads are cast via investment casting techniques, but
other casting methods can be used such as sand casting, die
casting, etc.
[0112] Casting does have its limitations, one of which being the
minimum wall thicknesses required. During casting, the molten metal
needs to flow through the various portions of the golf club head
and that flow can be inhibited by very thin portions. Casting
thinner than a minimum castable thickness can lead to voids and
porosity in the casting which decrease the strength and increase
stress risers in the golf club head. Therefore, it can be
impossible to cast some of the geometries described herein if the
thin regions are thinner than the minimum castable thickness. One
desirable geometry that is difficult to achieve with existing
casting methods, is a crown incorporating at least one thin region
that is thinner than the minimum castable thickness, one example of
which is illustrated in FIGS. 19 and 20. FIG. 19 illustrates a
perspective view of the golf club head 1000 of FIG. 18, including a
thin region 1230 located in the crown 1200. FIG. 20 illustrates a
cross-sectional view of the crown 1200 of FIG. 19. The crown 1200
of the golf club head 1000 includes a variable thickness geometry.
The crown 1200 includes an external surface 1210 and an internal
surface 1220. The internal surface 1220 is adjacent the hollow
interior of the golf club head 1000 and the external surface 1210
is opposite the internal surface 1220. The external surface is
substantially smooth. The internal surface includes a recess 1270,
causing the crown 1200 to have a thin region 1230 and a thick
region 1240. The thin region has a thickness T.sub.thin which is
less than the minimum castable thickness. The thick region has a
thickness T.sub.thick which is thicker than the thickness
T.sub.thin. The recess has a depth D.sub.r.
[0113] The minimum castable thickness to create repeatable quality
castings is typically greater than or equal to 0.52 mm. Recent
developments in casting techniques have had success casting as thin
as 0.48 mm. The "minimum castable thickness" will be defined as
0.48 mm herein unless noted otherwise. Typically, the thick region
will have a thickness greater than or equal to the minimum castable
thickness. The thickness of the thin region T.sub.thin is
preferably less than or equal to 0.45 mm. In an additional
embodiment, the thickness of the thin region T.sub.thin is
preferably less than or equal to 0.35 mm. In an additional
embodiment, the thickness of the thin region T.sub.thin is
preferably less than or equal to 0.25 mm. The depth of the recess
D.sub.r can be greater than or equal to 0.05 mm and less than or
equal to 0.35 mm. In an additional embodiment, the depth of the
recess D.sub.r can be greater than or equal to 0.15 mm and less
than or equal to 0.25 mm. In an additional embodiment, the depth of
the recess D.sub.r can be approximately 0.20 mm.
[0114] One way to overcome the casting limitations described above,
is a new and creative method of creating variable thickness
geometries in golf club heads, which is illustrated in FIGS. 21 and
22. This method can be applied to a crown, as described herein, or
it can be applied to other portions of a golf club head, which may
include for example, the striking face, the sole, etc. The method
is particularly applicable to a face-pull cast construction as
described above wherein the body portion is cast. The method
incorporates specific casting geometries and chemical etching,
which can also be referred to as chemical milling or industrial
etching. Chemical etching uses etching chemicals to remove material
from a golf club head. The material to be removed is normally put
in a bath of the etching chemical, a corrosive chemical, sometimes
called an etchant, which reacts with the material and causes the
material to be dissolved. The amount of material dissolved
generally depends on how long the material is exposed to the
etching chemical.
[0115] Masking can be utilized to prevent the etching chemical from
removing material from particular portions of the golf club head.
Masking layers are generally formed of inert substances and can be
applied to the golf club head in a variety of ways, which may
include, for example, dipping, painting, flow coating,
electrostatic deposition, adhesive sheet, etc. After the chemical
etching is complete, the masking layer can be removed.
[0116] The casting and etching method is illustrated in FIGS.
21A-21D and outlined in FIG. 22. First 10001, the body portion of
the golf club head is cast. In this embodiment, the desired
variable thickness geometry is located in the crown 1200 of the
golf club head. FIG. 21A illustrates a cross-sectional view of a
crown 1200 after casting. Like the finished crown in FIG. 20, the
crown 1200 in FIG. 21A includes a recess on the internal surface
1220. Unlike the finished crown 1200 in FIG. 20, the crown 1200 in
FIG. 21A includes a sacrificial protrusion 1280 on the external
surface of the crown 1200. The crown 1200 includes a first region
1201 and a second region 1202. The first region 1201 is where the
final product will include a thin region 1230. The first region
1201 includes the protrusion 1280 and the recess 1270. The second
region is adjacent the protrusion 1280 and recess 1270. In some
embodiments, the second region 1202 substantially surrounds the
first region 1201. The protrusion 1280 extends outwards beyond the
external surface of the second region 1202. The second region 1202
has a thickness T.sub.2. The first region 1201 has a thickness
T.sub.1. Thickness T.sub.2 is equal to or greater than the minimum
castable thickness in order to facilitate quality and consistent
casting results. In some embodiments, thickness T.sub.1 is
substantially similar to thickness T.sub.2. The face insert 1110,
or any other portion of the golf club head 1000, can be welded to
the body portion 1610 at this time as well.
[0117] Next 10002, a mask 9000 is applied to the external surface
1210 of the second region 1202 of the crown 1200, as illustrated in
FIG. 21B. A mask is not applied to the external surface 1210 of the
first region 1201. Masking can be applied the entire casting minus
the first region 1201. Additionally, any holes from the hollow golf
club head interior to the exterior of the golf club head can be
plugged, preventing the etching material from entering the hollow
interior of the golf club head.
[0118] Next 10003, the crown 1200 is exposed to an etching
chemical, as illustrated in FIG. 21C. The etching chemical removes
material from the first region 1201, removing the sacrificial
protrusion 1280, until the external surface 1210 of the first
region 1201 is substantially flush with the external surface 1201
of the second portion. In another embodiment, the etching chemical
removes material from the first region 1201, until the thickness
T.sub.1 is less than the minimum castable thickness, or until it
reaches T.sub.thin. After a specified amount of time 10004, the
etching chemical is removed from the golf club head. In one
embodiment, the entire club head is dipped into the etching
chemical. In another embodiment, a specific portion of the club
head can be lowered into an etching chemical, such as the crown,
only partially submerging the golf club head.
[0119] Finally 10005, the mask 9000 is removed from the second
region 1202 of the crown 1200. The end product is a crown 1200, as
illustrated in FIG. 21D, where the external surface 1210 of the
first region 1201 is substantially flush with the external surface
1210 of the second region 1202. The chemical etching has reduced
the thickness of the first region 1201 by removing the sacrificial
protrusion, creating a thin region 1230 adjacent the thick region
1240. Some embodiments include an additional step 10006 of
polishing the external surface 1210 of the golf club head 100 to
ensure the external surface 1210 is smooth and the external surface
1210 of the first region 1201 is substantially flush with the
external surface 1210 of the second region 1202.
[0120] The casting and chemical etching method described herein can
be used to create a variety of variable thickness geometries,
including but not limited to those described herein relative to the
chemical etching method as well as the stamped forging process.
[0121] Other than in the operating example, or unless otherwise
expressly specified, all of the numerical ranges, amounts, values
and percentages such as those for amounts of materials, moment of
inertias, center of gravity locations, loft, draft angles, various
performance ratios, and others in the aforementioned portions of
the specification may be read as if prefaced by the word "about"
even though the term "about" may not expressly appear in the value,
amount, or range. Accordingly, unless indicated to the contrary,
the numerical parameters set forth in the above specification and
attached claims are approximations that may vary depending upon the
desired properties sought to be obtained by the present invention.
At the very least, and not as an attempt to limit the application
of the doctrine of equivalents to the scope of the claims, each
numerical parameter should at least be construed in light of the
number of reported significant digits and by applying ordinary
rounding techniques.
[0122] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations,
the numerical values set forth in the specific examples are
reported as precisely as possible. Any numerical value, however,
inherently contains certain errors necessarily resulting from the
standard deviation found in their respective testing measurements.
Furthermore, when numerical ranges of varying scope are set forth
herein, it is contemplated that any combination of these values
inclusive of the recited values may be used.
[0123] It should be understood, of course, that the foregoing
relates to exemplary embodiments of the present invention and that
modifications may be made without departing from the spirit and
scope of the invention as set forth in the following claims.
* * * * *