U.S. patent application number 14/591573 was filed with the patent office on 2015-05-07 for golf club head with high specific-gravity materials.
The applicant listed for this patent is Cobra Golf Incorporated. Invention is credited to Tim A. Beno, Andrew Curtis, Ryan L. Roach, Peter L. Soracco, Michael S. Yagley.
Application Number | 20150126303 14/591573 |
Document ID | / |
Family ID | 47627283 |
Filed Date | 2015-05-07 |
United States Patent
Application |
20150126303 |
Kind Code |
A1 |
Roach; Ryan L. ; et
al. |
May 7, 2015 |
GOLF CLUB HEAD WITH HIGH SPECIFIC-GRAVITY MATERIALS
Abstract
Golf club heads comprising weighted materials that can be added,
removed, and moved in order to change the weight and center of
gravity of the club. In some instances, the weighted material is a
polymer composition comprising metal and having a specific gravity
greater than about 4. Also disclosed are methods of modifying the
center of gravity of a golf club head and methods of manufacturing
golf club heads.
Inventors: |
Roach; Ryan L.; (Carlsbad,
CA) ; Soracco; Peter L.; (Carlsbad, CA) ;
Beno; Tim A.; (San Diego, CA) ; Curtis; Andrew;
(San Diego, CA) ; Yagley; Michael S.; (Carlsbad,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cobra Golf Incorporated |
Carlsbad |
CA |
US |
|
|
Family ID: |
47627283 |
Appl. No.: |
14/591573 |
Filed: |
January 7, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13644516 |
Oct 4, 2012 |
8938871 |
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14591573 |
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|
12581975 |
Oct 20, 2009 |
8303433 |
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13644516 |
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|
12076322 |
Mar 17, 2008 |
8007371 |
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12581975 |
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11363098 |
Feb 28, 2006 |
7524249 |
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12076322 |
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11180406 |
Jul 13, 2005 |
7377860 |
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11363098 |
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11110733 |
Apr 21, 2005 |
7658686 |
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11180406 |
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Current U.S.
Class: |
473/335 |
Current CPC
Class: |
A63B 53/042 20200801;
B23P 6/00 20130101; A63B 53/0466 20130101; A63B 53/0416 20200801;
A63B 53/0433 20200801; A63B 2209/023 20130101; Y10T 29/49746
20150115; Y10T 29/49742 20150115; A63B 53/04 20130101; A63B 53/08
20130101; A63B 2053/0491 20130101; A63B 53/06 20130101; Y10T
29/49737 20150115; A63B 2210/50 20130101; A63B 53/0412 20200801;
A63B 2053/0495 20130101; A63B 53/0437 20200801; A63B 60/00
20151001; A63B 53/0408 20200801; Y10T 29/49716 20150115; A63B
2209/00 20130101; Y10T 29/49993 20150115 |
Class at
Publication: |
473/335 |
International
Class: |
A63B 53/04 20060101
A63B053/04; A63B 53/06 20060101 A63B053/06 |
Claims
1. A golf club head comprising: a body comprising a face, a back, a
heel, a toe, a sole, and a crown that together form a hollow,
interior volume of the club head, the body including a removable
portion providing access to the interior volume of the club head;
and a polymer composition comprising a metal and having a specific
gravity greater than about 4.
2. The golf club head of claim 1, wherein the polymer composition
comprises a polymer selected from the group consisting of epoxides,
urethanes, dimethylsiloxanes, polysiloxanes, chloroprenes,
acrylics, and acetates.
3. The golf club head of claim 1, wherein the metal is selected
from tungsten, nickel, copper, iron, gold, platinum, lead, silver,
molybdenum, silver, and uranium.
4. The golf club head of claim 1, wherein the golf club head
additionally comprises a port providing access to the interior of
the club head.
5. The golf club head of claim 1, wherein the polymer composition
contacts a portion of the interior volume of the club head.
6. The golf club of claim 5, wherein the interior of the club head
comprises a depression for receiving the polymer composition.
7. The golf club head of claim 1, wherein the polymer composition
contacts the exterior of the club head.
8. The golf club head of claim 1, wherein the polymer composition
contacts the sole of the club head.
9. The golf club head of claim 1, wherein the polymer composition
is a coating.
10. The golf club head of claim 1, wherein the polymer composition
is a putty.
11. The golf club head of claim 1, wherein the polymer composition
is a solid.
12. The golf club head of claim 1, wherein the polymer composition
is removable.
13. A golf club head comprising: a body comprising a face, a back,
a heel, a toe, a sole, and a crown that together form a hollow,
interior volume of the club head, the body including a port
providing access to the interior volume of the club head; and a
polymer composition comprising a metal and having a specific
gravity greater than about 4.
14. The golf club head of claim 13, wherein the metal is selected
from tungsten, nickel, copper, iron, gold, platinum, lead, silver,
molybdenum, silver, and uranium.
15.-22. (canceled)
23. A golf club head comprising: a body comprising a face, a back,
a heel, a toe, a sole, and a crown that together form a hollow,
interior volume of the club head, the body including a movable
portion providing access to the interior volume of the club head;
and a polymer composition comprising a metal and having a specific
gravity greater than about 4.
24. The golf club head of claim 23, wherein the polymer composition
comprises a polymer selected from the group consisting of epoxides,
urethanes, dimethylsiloxanes, polysiloxanes, chloroprenes,
acrylics, and acetates and the metal is selected from tungsten,
nickel, copper, iron, gold, platinum, lead, silver, molybdenum,
silver, and uranium.
25. The golf club head of claim 23, wherein the polymer composition
contacts a portion of an interior surface of the interior volume of
the club head.
26. The golf club head of claim 25, wherein the polymer composition
contacts an interior surface of the sole of the club head.
27. The golf club head of claim 23, wherein the polymer composition
is adjustable.
28. The golf club head of claim 23, wherein the polymer composition
is removable from the interior volume of the club head.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 12/581,975, filed Oct. 20, 2009, now pending,
which is a continuation-in-part of U.S. patent application Ser. No.
12/076,322, filed on Mar. 17, 2008, now U.S. Pat. No. 8,007,371,
which is a continuation-in-part of U.S. patent application Ser. No.
11/363,098, filed on Feb. 28, 2006, now U.S. Pat. No. 7,524,249,
which is a continuation-in-part of U.S. patent application Ser. No.
11/110,733, filed on Apr. 21, 2005, now U.S. Pat. No. 7,658,686.
U.S. patent application Ser. No. 11/363,098 is also a
continuation-in-part of U.S. patent application Ser. No.
11/180,406, filed on Jul. 13, 2005, now U.S. Pat. No. 7,377,860.
Each of these applications is incorporated herein by reference in
their entireties.
FIELD OF THE INVENTION
[0002] The present invention generally relates to a golf club head
with enhanced weight distribution and mechanical properties. In
particular, the present invention relates to a metal wood type club
with a moveable insert, which allows for a maximization of legal
club head dimensions and the ability to manipulate various
characteristics of the club head.
BACKGROUND OF THE INVENTION
[0003] Golf club heads come in many different forms and makes, such
as wood- or metal-type (including drivers and fairway woods),
iron-type (including wedge-type club heads), utility- or
specialty-type, and putter-type. Each of these styles has a
prescribed function and make-up. The present invention primarily
relates to hollow golf club heads, such as wood-type and
utility-type (generally referred to herein as wood-type golf
clubs).
[0004] Wood-type type golf club heads generally include a front or
striking face, a crown, a sole, and an arcuate skirt including a
heel, a toe, and a back. The crown and skirt are sometimes referred
to as a "shell." The front face interfaces with and strikes the
golf ball. A plurality of grooves, sometimes referred to as "score
lines," may be provided on the face to assist in imparting spin to
the ball and for decorative purposes. The crown is generally
configured to have a particular look to the golfer and to provide
structural rigidity for the striking face. The sole of the golf
club contacts and interacts with the ground during the swing.
[0005] The design and manufacture of wood-type golf clubs requires
careful attention to club head construction. Among the many factors
that must be considered are material selection, material treatment,
structural integrity, and overall geometrical design. Exemplary
geometrical design considerations include loft, lie, face angle,
horizontal face bulge, vertical face roll, face size, sole
curvature, center of gravity, and overall head weight. In addition,
the interior design of the club head may be tailored to achieve
particular characteristics, such as by including hosel or shaft
attachment means, perimeter weighting on the face or body of the
club head, and fillers within hollow club heads.
[0006] Club heads typically are formed from stainless steel,
aluminum, or titanium, and may be cast, stamped by forming sheet
metal with pressure, forged, or formed by a combination of any two
or more of these processes. In fact, clubs were originally
manufactured primarily by casting durable metallic material such as
stainless steel, aluminum, beryllium copper, etc. into a unitary
structure comprising a metal body, face, and hosel. However, as
technology progressed, it became more desirable to increase the
performance of the face of the club, usually by using a titanium
material. Today, the club heads may be formed from multiple pieces
that are welded or otherwise joined together to form a hollow head,
as is often the case of club heads designed with inserts, such as
sole plates or crown plates.
[0007] The multi-piece constructions facilitate access to the
cavity formed within the club head, thereby permitting the
attachment of various other components to the head such as internal
weights and the club shaft. The cavity may remain empty, or may be
partially or completely filled, such as with foam. In addition, due
to difficulties in manufacturing one-piece club heads to high
dimensional tolerances, the use of multi-piece constructions allows
the manufacture of a club head to adhere to a tighter set of
standards.
[0008] In the case of one-piece heads, it may be necessary to
inject an adhesive into the club head to provide the correct swing
weight and to collect and retain any debris that may be in the club
head. Known in the industry as "rat glue" or "rattle glue" this
adhesive is often used in the finishing of hollow club head such as
metal drivers and hybrid. The adhesive is typically injected as one
of the last steps in the fabrication process, and may be thermoset,
or hot-injected and allowed to cool and solidify. In some
instances, it is advantageous for the adhesive to remain tacky
throughout the life of the club in order to sequester internal
debris that is dislocated as the club is used, i.e., due to
repeated striking. Typically the adhesive is injected through a
small hole in the club head and allowed to distribute throughout
the interior.
[0009] With a high percentage of amateur golfers constantly
searching for more distance on their shots, particularly their
drives, the golf industry has responded by providing golf clubs
specifically designed with distance in mind. The head sizes of
wood-type golf clubs have increased, allowing the club to possess a
higher moment of inertia, which translates to a greater ability to
resist twisting on off-center hits. As a wood-type club head
becomes larger, its center of gravity will be moved back away from
the face and further toward the toe, resulting in hits flying
higher and further to the right than expected (for right-handed
golfers). And, because the center of gravity is moved further away
from hosel axis, the larger heads can also cause these clubs to
remain open on contact, thereby inducing a "slice" effect (in the
case of a right-handed golfer the ball deviates to the right).
[0010] While a reduction in loft of a larger club head, offsetting
the head, and/or incorporating a hook face angle may help to
compensate for this shift in the center of gravity and resulting
higher and right-biased hits by "squaring" the face at impact, none
of these methods are completely sufficient in solving the issues
relating to the larger club heads.
[0011] Another technological breakthrough in recent years to
provide the average golfer with more distance is to make larger
head clubs while keeping the weight constant or even lighter by
casting consistently thinner shell thicknesses and using lighter
materials such as titanium, magnesium, and composites. Also, the
faces of the clubs have been steadily becoming extremely thin,
because a thinner face will maximize what is known as the
Coefficient of Restitution (COR). For example, the more a face
rebounds upon impact, the more energy is imparted to the ball,
thereby increasing the resulting shot distance.
[0012] With the emphasis on thinner shells, strategic weighting has
become important to club manufacturers. Accordingly, weight
elements are usually placed at specific locations believed to have
a positive influence on the flight of the ball or to overcome a
particular golfer's shortcomings. As previously stated, a major
problem area of the higher handicap golfer is the tendency to
"slice," which, in addition to deviating the ball to the right,
also imparts a greater spin to the ball, thus further reducing the
overall shot distance.
[0013] As such, a need exists in the art to further enhance weight
distribution of a golf club head in order to reduce or eliminate
the higher spin and "slice effect" currently an issue with the
larger club heads. In addition, it would be advantageous to
maximize playability of the club by maximizing the dimensions
allowable by the USGA, both heel to toe and face to back. The
present invention contemplates such enhancements.
SUMMARY OF THE INVENTION
[0014] The present invention is directed to golf club heads and
methods for adjusting the distribution of weight in the heads,
thereby changing the center of gravity in the heads. The weight
distribution may be modified at various points in the club head
life. In some embodiments, the weight distribution is adjusted by
the user. In other embodiments, the weight is adjusted during
manufacturing or by a professional using specialized tools at a
fitting.
[0015] In one instance the invention is a golf club head comprising
a body defined by a face, a back, a heel, a toe, a sole, a crown,
and at least one adjustable insert. The adjustable insert is
capable of movement in the face to back direction. The adjustable
insert has at least one adjustment mechanism and at least one
locking mechanism, which allows for the insert to be locked into at
least one position. In one embodiment, the insert is capable of
movement in increments of less than about 0.05 inch. According to
one aspect of the invention, the adjustable insert is rotatable
about a center axis. The adjustment mechanism may take many forms.
For example, the adjustment mechanism may comprise a plurality of
notches located on the body of the club head and a deformable tab
located on the adjustable insert and designed to fit within a
notch.
[0016] The club head has a first distance from the toe to the heel.
In addition, the club head has a second distance from the face to
the back without the adjustable insert. Finally, the club head has
a third distance from the face to the back of the adjustable insert
when the insert is extended to a maximum in the face to back
direction. In one embodiment, the third distance is greater than
about 5 inches. The third distance may be greater than or equal to
the first distance times 1.10. The third distance may be greater
than or equal to the first distance times 1.05. In another
embodiment, the third distance may be greater than or equal to the
first distance times 1.00. The third distance may be greater than
or equal to 1.05 times the second distance. In another embodiment,
the third distance may be greater than or equal to 1.50 times the
second distance.
[0017] In one embodiment, the adjustable insert comprises a portion
with a specific gravity greater than the specific gravity of the
body. For example, the specific gravity of a portion of the insert
may be about 7 or more. The high specific gravity portion may
comprise less than about 40 percent of the total volume of the
adjustable insert. In one embodiment, the high specific gravity
portion may be less than about 20 percent of the total volume of
the adjustable insert. The high specific gravity portion may be
located substantially on the toe side, the heel side, or on both
sides of the insert.
[0018] According to one aspect of the invention, the adjustable
insert may have a low specific gravity portion with a specific
gravity lower than that of the body. For example, the specific
gravity of the low specific gravity portion may be less than about
4. In another embodiment, the adjustable insert further comprises a
first portion and a second portion, the second portion has a
specific gravity greater than the first portion, and the second
portion comprises up to about 30 percent of the total volume of the
adjustable insert.
[0019] In another instance, the invention is a golf club head
having a weighted component comprising a polymer composition and a
metal. The polymer composition, including the metal, has a specific
gravity greater than about 4. Typically, the weighted polymer
composition is used with a golf club head having a body comprising
a face, a back, a heel, a toe, a sole, and a crown that together
form a hollow, interior volume of the club head. The polymer
composition may be a spray coating, a putty, or an adhesive that
dries to a solid. In some embodiments, the club head has
depressions for receiving the polymer composition. In some
embodiments, the golf club head comprises a removable portion that
provides access to the interior of the club head. In other
embodiments, the golf club head comprises a port, and the polymer
composition is injected into the head through the port.
[0020] In another instance, the invention is a method of modifying
the center of gravity of a golf club head comprising removing a
portion of the club head to access the interior of the club head,
contacting the interior of the club head with a polymer composition
comprising a metal and having a specific gravity greater than about
4, and reassembling the club head. A related method may be used to
modify the center of gravity of a golf club head, comprising
removing a portion of a club head to access the interior of the
club head, removing from the interior of the club head a polymer
composition comprising a metal and having a specific gravity
greater than about 4, and reassembling the club head. Also
disclosed are kits for modifying the center of gravity of a golf
club head including instructions and a polymer composition
comprising a metal. In some embodiments, the kits additionally
include a club head and a tool for removing a portion of the club
head to access the interior of the club head. In some embodiments,
the kits additionally include a golf club, having a club head, and
a tool for removing a portion of the club head to access the
interior of the club head. In some embodiments, the instructions
comprise directions for accessing multimedia content regarding
modifying the center of gravity of a golf club head via a network,
e.g., via the internet.
[0021] In another aspect, the invention includes a method of
manufacturing a golf club head comprising inserting a directional
applicator through a port in the golf club head into the interior
volume of the club head and injecting a polymer composition having
a specific gravity greater than about 4 into the interior volume of
the club head. In some embodiments, the polymer composition is
injected substantially toward the toe or the sole of the club.
[0022] Additional aspects of the invention will be evident to one
of skill in the art upon viewing the below disclosure and
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The present invention is described with reference to the
accompanying drawings, in which like reference characters reference
like elements, and wherein:
[0024] FIG. 1 shows a golf club head of the present invention;
[0025] FIG. 2 shows a body member of the golf club head of FIG.
1;
[0026] FIG. 3 shows a second club head of the present
invention;
[0027] FIG. 4 shows a bottom view of the club head of FIG. 3;
[0028] FIG. 5 shows a bottom perspective view of a club head of the
present invention;
[0029] FIG. 6 shows a rear elevation view of the club head of FIG.
5;
[0030] FIG. 7 shows a heel elevation view of the club head of FIG.
5;
[0031] FIG. 8 shows a bottom schematic view of the club head of
FIG. 5;
[0032] FIG. 9 shows a front cross-sectional view of the club head
of FIG. 5;
[0033] FIG. 10 shows a bottom view of a golf club head of the
present invention;
[0034] FIG. 11 shows a bottom view of a golf club head of the
present invention;
[0035] FIG. 12 shows a cross-sectional view of the club head of
FIG. 11 taken along line 12-12;
[0036] FIG. 13 shows an exploded top view of a golf club head of
the present invention;
[0037] FIG. 14 shows an exploded top view of the golf club head of
FIG. 13;
[0038] FIG. 15 shows a first club head component and its projected
area;
[0039] FIG. 16 shows a second club head component and its projected
area;
[0040] FIG. 17 shows a top view of the club head of FIG. 13;
[0041] FIG. 18 shows a club head of the invention with an
adjustable insert;
[0042] FIG. 19 is a toe side view of the golf club head shown in
FIG. 18;
[0043] FIG. 20 is a top view of the golf club head of the club head
of FIG. 18;
[0044] FIG. 21 is a rear view of the golf club head of the club
head of FIG. 18;
[0045] FIG. 22 is a top view of a club head of the invention with a
fully extended adjustable insert;
[0046] FIG. 23 shows the adjustable insert of FIG. 22 according to
an embodiment of the invention;
[0047] FIG. 24 is a side view of a club head of the invention with
an adjustable insert;
[0048] FIG. 25 shows a top view of a club head of the
invention;
[0049] FIG. 26 shows an embodiment of a club head with a detachable
face plate to allow access to the interior of the club head;
[0050] FIG. 27 shows spraying a high-specific gravity coating
inside a club head;
[0051] FIG. 28 shows a high specific-gravity coating distributed on
the interior of the sole of a club head;
[0052] FIG. 29 shows placement of a high specific-gravity
conformable material inside a club head;
[0053] FIG. 30 shows placement of a high specific-gravity
conformable material inside a club head;
[0054] FIG. 31 shows placement of a high specific-gravity adhesive
mixture inside an indexed depression inside a club head; and
[0055] FIG. 32 shows a cured high specific-gravity adhesive in an
indexed depression inside a club head.
DETAILED DESCRIPTION OF THE INVENTION
[0056] The present invention is directed to enhanced weighting of a
club head. In one aspect of the invention, weight elements are
incorporated directly into the club head. The placement of weight
elements is designed so that the spin of the ball will be reduced
and also so that a "draw" (a right-to-left ball flight for a
right-handed golfer) will be imparted to the ball flight. This ball
flight pattern is also designed to help the distance-challenged
golfer because a ball with a lower spin rate will generally roll a
greater distance after initially contacting the ground than would a
ball with a greater spin rate.
[0057] In another aspect of the invention, the club head has an
adjustable insert that is capable of movement in the face to back
direction and is further capable of locking into a desired
location. The insert may be adjusted so that the total distance
from the face to the back of the club when the insert is fully
extended approaches about 5 inches. The total distance from the
face to the back of the club when the insert is fully extended may
be related to the distance from the toe to the heel. For example,
the total distance from the face to the back with the insert at a
fully extended position may be greater than the distance from the
toe to the heel of the golf club, which allows for the golfer to
adjust the face to back distance to approach a predetermined
distance.
[0058] In yet another aspect of the invention, at least a portion
of the club head of the invention is treated with a thermal or
combustion spray coating to alter the weight distribution of the
club head. The coating may be applied to the interior and/or
exterior of the club head. The club head may also be weighted using
conformable materials (shapeable to fill a space) with high
specific gravities, such as putties, glues, caulk, and adhesives.
In some instances, the conformable materials are applied with
special applicators using access ports in club heads.
[0059] A wide variety of materials are available that provide the
needed characteristics of high specific gravity, strength, and
workability. Table 1 shows an exemplary list of materials suitable
for use with the invention and corresponding specific gravities.
The materials may be incorporated into aspects of the invention,
described below, as pure materials, as alloys, or as mixtures, for
example tungsten filings in an epoxy resin.
TABLE-US-00001 TABLE 1 Specific Gravities of Some Materials
Specific Gravity Material (relative to pure water) Aluminum 2.5
Brass 8.2-8.7 Cast Iron 6.8-7.8 Copper 8.9 Gold 19.3 Lead 11.3
Molybdenum 10.2 Nickel 8.8 Platinum 21.4 Silver 10.5 Stainless
Steel 7.5-8.0 Tin 7.3 Tungsten 19.6 Uranium (depleted) 18.9 Zinc
7.1
[0060] Each aspect is discussed in greater detail below.
Weighted Inserts
[0061] FIG. 1 shows a golf club head 1 of the present invention.
The club head 1 includes a body 10 having a strike face 11, a sole
12, a crown 13, a skirt 14, and a hosel 15. The body 10 defines a
hollow, interior volume 16. Foam or other material may partially or
completely fill the interior volume 16. Weights may optionally be
included within the interior volume 16. The face 11 may be provided
with grooves or score lines therein of varying design. The club
head 1 has a toe T and a heel H.
[0062] The club head 1 is comprised of a plurality of body members
that cooperatively define the interior volume 16. A first body
member 101 includes a sole portion and a face portion. The first
body member 101 may include a complete face 11 and sole 12.
Alternatively, either or both the face 11 and the sole 12 can be
inserts coupled to the first body member 101. The club head 1 also
includes at least one second body member 102 coupled to the first
body member 101 along the skirt 14 in known fashion. The crown 13
can be unitarily a portion of either body member 101, 102 or it may
be an insert coupled to either of the body members 101, 102. The
second body member 102 includes a concave portion 20 that, when the
body members 101, 102 are coupled together, extends inward into the
interior volume 16. FIG. 2 shows an isolated view of an exemplary
second body member 102.
[0063] The first body member 101 preferably is formed of a metallic
material such as stainless steel, aluminum, or titanium. The
material of the first body member 101 is chosen such that it can
withstand the stresses and strains incurred during a golf swing,
including those generated through striking a golf ball or the
ground. The club head 1 can be engineered to create a primary load
bearing structure that can repeatedly withstand such forces. Other
portions of the club head 1, such as the skirt 14, experience a
reduced level of stress and strain and advantageously can be
replaced with a lighter, weight-efficient secondary material.
Lighter weight materials, such as low density metal alloys,
plastic, composite, and the like, which have a lower density or
equivalent density than the previously mentioned metallic
materials, can be used in these areas, beneficially allowing the
club head designer to redistribute the "saved" weight or mass to
other, more beneficial locations of the club head 1. These portions
of the club head 1 can also be made thinner, enhancing the weight
savings.
[0064] Exemplary uses for this redistributed weight include
increasing the overall size of the club head 1, expanding the size
of the club head "sweet spot," which is a term that refers to the
area of the face 11 that results in a desirable golf shot upon
striking a golf ball, repositioning the club head 1 center of
gravity, and/or producing a greater moment of inertia (MOI).
Inertia is a property of matter by which a body remains at rest or
in uniform motion unless acted upon by some external force. MOI is
a measure of the resistance of a body to angular acceleration about
a given axis, and is equal to the sum of the products of each
element of mass in the body and the square of the element's
distance from the axis. Thus, as the distance from the axis
increases, the MOI increases, making the club more forgiving for
off-center hits since less energy is lost during impact from club
head twisting. Moving or rearranging mass to the club head
perimeter enlarges the sweet spot and produces a more forgiving
club. Increasing the club head size and moving as much mass as
possible to the extreme outermost areas of the club head 1, such as
the heel H, the toe T, or the sole 12, maximizes the opportunity to
enlarge the sweet spot or produce a greater MOI, making the golf
club hotter and more forgiving.
[0065] The second body member 102 is light-weight, which gives the
opportunity to displace the club head center of gravity downward
and to free weight for more beneficial placement elsewhere without
increasing the overall weight of the club head 1. When the wall
thickness of the second body member 102 is at the minimum range of
the preferred thickness, a reinforcing body layer can be added in
the critical areas in case the member shows deformations. These
benefits can be further enhanced by making the second body member
102 thin. To ensure that the structural integrity of the club head
1 is maintained, these thin panels may preferably include a concave
portion 20. Inclusion of these concave portions 20 allow the second
body member 102 to withstand greater stress, both longitudinally
and transversely, without sustaining permanent deformation or
affecting the original cosmetic condition, ensuring the structural
integrity of the club head 1 is maintained.
[0066] In one embodiment, the thickness for the first body member
101 may range from about 0.03 inch to about 0.05 inch, preferably
from about 0.035 to about 0.045 inch. The thickness for the second
body member 102 may range from about 0.015 inch to about 0.025
inch, preferably from about 0.018 inch to about 0.022 inch.
[0067] The concave portion 20 may displace at least about 10 cubic
centimeters. More preferably, the concave portion 20 displaces at
least about 20 cubic centimeters, and even more preferably, about
25 cubic centimeters. While the club head 1 can be virtually any
size, preferably it is a legal club head. A plurality of concave
portions 20 may be used with the club head 1. For example, concave
portions 20 of uniform or varying size may be positioned in the
toe, heel, back, etc.
[0068] FIG. 3 shows a cross-sectional view taken substantially
perpendicular to the face 11 of a second club head 2 of the present
invention, and FIG. 4 shows a bottom view of the club head 2. In
the illustration of this embodiment, the concave portion 20 is
positioned at the back of the club head 2. The concave portion 20
preferably is not visible to the golfer at address. In addition to
the concave portion 20, the second body member 102 further includes
a convex bulge 22 that extends generally away from the interior
volume 16.
[0069] At least one insert 23 may be positioned within the convex
bulge 22. The insert 23 is not visible from outside the club head
2, and is thus illustrated using broken lines. In a preferred
embodiment, the insert 23 is a weight insert. The convex nature of
the bulge 23 allows the weight to be positioned to maximize the
mechanical advantage it lends to the club head 2.
[0070] As shown in FIG. 4, the club head 2 may include a plurality
of convex bulges 22, such as on a heel side and on a toe side of
the club head 2. The club designer may place inserts 23 as desired
within the bulges 22. The masses of the inserts may be
substantially equal. Alternatively, one of the inserts may have a
greater mass than the other. This may be beneficial to design the
club to correct a hook swing or a slice swing. A preferred mass
range for the weight insert 23 is from 1 gram to 50 grams.
[0071] As shown in FIG. 3, the first body member 101 may comprise a
majority of the sole 12 and the second body member 102 may include
a majority of the crown 13. This beneficially removes a large
majority of the mass from the upper part of the club head 2. In
this embodiment, the first body member 101 includes an attachment
perimeter 18 that extends around its edge. The second body member
102 is coupled to the first body member 101 along the attachment
perimeter 18. Thus, the first and second body members 101, 102
cooperatively define the interior volume 16.
[0072] The attachment perimeter 18 preferably may contain a step
defining two attachment surfaces 18a, 18b. As illustrated, the
second body member 102 may be coupled to both of these surfaces
18a, 18b to help ensure a strong bond between the body members 101,
102.
[0073] While the body members 101, 102 may be formed in a variety
of manners, a preferred manner includes forming a complete club
head shell (first body member 101) in known manner and removing
material to create openings to which the second body member 102 can
be coupled. The opening may be created in any desired manner, such
as with a laser. The second body member 102 may be joined to the
first body member 101 in a variety of manners, such as through
bonding or through a snap-fit in conjunction with bonding. If a
composite material is used for the concave inserts, molding six
plies of 0/90/45/-45/90/0 is preferred.
[0074] FIGS. 5-9 illustrate additional aspects of the present
invention. In the embodiment illustrated in these figures, the club
head 1 includes a crown portion 13, a sole 12, a heel portion H, a
toe portion T, a skirt portion 14 connecting the heel portion H to
the toe portion T, a front face 11 and a hosel 24 that extends from
the heel portion H. The club head 1 can be formed from sheets
joined together, such as by welding, or cast, preferably from a
titanium alloy. The crown portion 13 can be made from such
materials as carbon fiber composite, polypropylene, Kevlar,
magnesium, continuous fiber reinforced thermoplastic, BMC, or a
thermoplastic. Hosel 24 includes a bore defining a centerline axis
C/L.
[0075] As best depicted in FIG. 9, the club head 1 of the present
invention has a center of gravity G located at an extremely
rearward and low position. The location of the center of gravity G
is biased by the location of two secondary weights, a toe secondary
weight 26 and a heel secondary weight 28, which are both partially
outside the traditional look of a golf club head. As shown in FIGS.
5-9, the locations of the two secondary weight elements 26, 28 are
established by the relationship of their distances from established
points of contact. When the club head is at a lie angle o of
59.degree., the lowest contact point of the sole 12 is at a center
point C directly beneath the center of gravity G.
[0076] One method of establishing the locations of the secondary
weights 26, 28 is discussed herein. As shown in FIG. 8, the center
line C/L of hosel 24 intersects the sole plate 12 at a distance D
from the rear surface of the front face 11. When extending a line
B-B that is substantially parallel to the leading edge of the club
head (maintaining the distance D), an intersection point P is made
with a line A-A that is perpendicular to and extends rearward from
the midpoint of the front face 11. The line A-A extends through the
middle of the club head 1 and passes directly beneath the club head
center of gravity G. This intersection point P may also be defined
by the intersection of line A-A and a vertical plane positioned at
an intersection of the hosel center line C/L and the sole 12.
[0077] The center of gravity C/G of each secondary weight 26, 28 is
at a distance W of at least 1.50 inches rearward of the
intersection point P, a distance Z that is a maximum of 0.25 inch
above the lowest point of contact, which is the center point C of
the sole plate 12 and each secondary weight is at least about 0.75
inch away from line A-A in opposing directions, which is a distance
Y1 towards the toe T for the toe secondary weight 26 and a distance
Y2 towards the heel H for the heel secondary weight 28.
[0078] The locations of the secondary weights 26, 28 may also be
determined for the present invention by measuring from the center
point C. From center point C, the center of gravity of each
secondary weight 26, 28 is a distance X of at least about 0.50 inch
rearward along line A-A, the distance Z that is a maximum of about
0.25 inch above the center point C, and a minimum of about 0.75
inch away from line A-A in opposing directions, towards the toe T
for the toe secondary weight 26 and towards the heel H for the heel
secondary weight 28. Thus, each secondary weight 26, 28 is a
minimum of about 0.90 inch from the center point C.
[0079] The secondary weights 26, 28 can be selected from a
plurality of weights designed to make specific adjustments to the
club head weight. The secondary weights 26, 28 can be welded into
place or attached by a bonding agent. The weights 26, 28 can be
formed from typically heavy weight inserts such as steel, nickel,
or tungsten. Preferably, the body of the club head 1 is formed from
titanium, and the crown portion 13 from a light-weight material
such as carbon fiber composite, polypropylene, Kevlar,
thermoplastic, BMC, magnesium, or some other suitable light-weight
material.
[0080] Preferred volumes of the club head 1 include from 350 cc to
460 cc. The secondary weights 26, 28 preferably range in mass from
2 to 35 grams, with 10 grams to 35 grams being more preferred. It
is well known that by varying parameters such as shaft flex points,
weights and stiffness, face angles, and club lofts, it is possible
to accommodate a wide spectrum of golfers. But the present
invention addresses the most important launch consideration, which
is to optimize the club head mass properties (center of gravity and
moment of inertia) by creating a center of gravity that is low,
rearward, and wide of center. The club head 1 of the present
invention encompasses areas of the club head that are not typically
utilized for weighting because they adversely alter the traditional
look of a club head. The design of this club head 1 allows for a
portion of the secondary weights 26, 28 to bulge outside the normal
contour of the club head.
[0081] FIG. 10 shows a bottom view of a golf club head 1 of the
present invention. The skirt 14 includes an opening 30 towards the
rear of the club head 1. An insert 35 is positioned within the
opening 30 in known fashion, such as via an attachment perimeter
18, to cooperatively define the interior volume 16. Preferably, the
insert 35 is formed of a light-weight material such as a composite
material or a polymer material. Using a light-weight insert 35
inherently biases the club head mass toward the sole 12 of the club
head 1. It also allows the inclusion of a weight member to achieve
a specific moment of inertia and/or center of gravity location
while maintaining typical values for the overall club head weight
and mass.
[0082] FIG. 11 shows a bottom view of a golf club head 1 of the
present invention. In addition to secondary weights 26, 28, the
club head 1 includes an insert 27 intermediate the toe secondary
weight 26 and the heel secondary weight 28. The insert 27 may be a
weight insert similar to the toe and heel secondary weights 26, 28,
in which case it also has a preferable mass range of 2 to 35 grams.
Alternatively, or in addition to being a weight member, insert 27
may include one or more indicia, such as a model or manufacturer
designation.
[0083] The club head 1 further includes a sole insert 105; in the
illustrated embodiment, two such sole inserts 105 are shown. These
inserts 105 preferably are formed of a light-weight material as
described above. Such materials likely are robust enough to
withstand contact with the ground such as the sole 12 incurs
through normal use of the golf club. However, the arcuate shape of
the sole 12 in the illustrated embodiment minimizes the likelihood
of the inserts 105 contacting the ground. Inclusion of the sole
inserts 105 frees even more mass for more beneficial placement in
the club head, such as at toe insert 26, intermediate insert 27,
and/or heel insert 28. The location of the inserts 105 toward the
center of the sole 12 inherently biases the mass toward the outer
portions of the club head 1, improving the club head MOI.
[0084] FIG. 12 shows a cross-sectional view of the club head 1 of
FIG. 11 taken along line 12-12. Here it is seen that the crown 13
is an insert that is coupled to the metallic first body member 101.
The crown insert 13 preferably is formed of a light-weight
material, beneficially displacing the club head center of gravity
downward and freeing yet more weight for more beneficial placement
elsewhere without increasing the overall weight of the club head 1.
Due to the inclusion of holes in which to position the crown insert
13, the skirt insert 35, the second body member inserts 102, and
the sole inserts 105, the first body member 101 takes on the
appearance of a frame.
[0085] It should be noted that not every insert 13, 35, 102, 105
need be included in a particular embodiment of the present
invention, though all may be present. The frame-like nature of
first body member 101 is a load bearing structure that ensures that
the stresses and strains incurred during a golf swing, including
those generated through striking a golf ball or the ground, do not
detrimentally affect the light-weight portions of the club head 1,
which experience a reduced level of stress and strain. These club
head portions, which may include secondary body member 102, crown
13, skirt insert 35, and sole inserts 105, advantageously can be
formed of a lighter, weight-efficient secondary material such as
low density metal alloys, plastics, composites, and the like, which
have a lower density or equivalent density than the previously
mentioned metallic materials, beneficially allowing the club head
designer to redistribute the "saved" weight or mass to other, more
beneficial locations of the club head 1. These portions of the club
head 1 can also be made thinner, enhancing the weight savings.
[0086] The first body member 101 preferably includes an attachment
perimeter 18 for each insert (including the crown 13). These
attachment perimeters 18 extend around the edge of the respective
openings. Preferably, each attachment perimeter 18 includes a step
defining two attachment surfaces 18a, 18b, which provide additional
assurance of a strong bond between the respective club head
components. (While each attachment perimeter 18 of FIG. 12 includes
a step defining two attachment surfaces 18a, 18b, such attachment
surfaces 18a, 18b are called-out in only one location for the sake
of clarity.)
[0087] The openings in the club head 1 into which the inserts 13,
35, 102, 105 are positioned preferably may be created by forming a
complete club head shell in known fashion, and then creating the
openings therein. One preferred method of creating the openings is
by using a laser to remove portions of the metallic material of the
first body member 101. This method provides for tight tolerances.
The attachment perimeter 18, including attachment surfaces 18a,
18b, may be formed in a variety of manners, such as machining the
first body member 101 after laser cutting the opening in the club
head 1.
[0088] Each sole insert 105 preferably has a mass of 0.5 gram to 10
grams, and more preferably from 1 gram to 5 grams. The sole inserts
305, as well as the other inserts, may be beveled or stepped
slightly to provide a location for any excess adhesive. In one
embodiment, the toe and heel sole inserts 26, 28 each have a
preferred mass range of 4 grams to 7 grams, while the intermediate
insert sole 27 has a preferred mass range of 2 grams to 3 grams. In
one embodiment, the thickness of the club head components is
tapered such that the walls are thicker towards the face 11 and
thinner towards the rear of the club head 1. Such wall thickness
tapering frees more mass for more beneficial placement in the club
head 1.
[0089] As discussed above, certain golf club head geometries have
an inherent advantage over typical design shapes with respect to
the club head's mass properties, especially in view of the
dimension limits mandated by the United States Golf Association
(USGA) and the Royal and Ancient Golf Club of St. Andrews
(R&A), the governing bodies promulgating the Rules of Golf. Two
such properties of particular note are the club head center of
gravity (CG) height and the club head MOI in the heel/toe twisting
direction about a vertical axis passing through the CG. (The limit
for this MOI is 5900 gcm.sup.2.)
[0090] Further to the discussion above, material selection and
distribution plays an important role in determining the club head
properties, including these two specific properties.
[0091] Modern drivers have gone from predominately made of steel in
the 1990s to titanium alloys in the 2000s as the driver size,
measured by volume, have gone from around 250 cc to the maximum
allowed 460 cc. While maintaining a certain volume as a constant,
the surface area of the club head may be varied. A sphere would be
the smallest body for a given volume, while a rectangle with twice
the footprint can have the same volume as the sphere. For example,
a sphere has a minimum amount of surface area surrounding a given
volume while the rectangle has a much greater amount of surface
area. With that logic, and the fact that there are inherent limits
to how thin walls can be made using certain metals--and furthermore
if the walls do reach the desired minimal thickness, secondary
durability issues, such as denting, arise--certain materials reach
their practical limit. While stiffening ribs can be added to help
overcome denting, this becomes a complex and costly solution and
may offer only marginal improvement.
[0092] Considering for example titanium, which has a density of
approximately 4.43 gm/cc, current manufacturing techniques can
obtain wall thickness in the range of 0.5-0.7 mm at a reasonable
cost. For a "traditional" shaped profile for a 460 cc driver
approaching the Rule limits in width and depth of 12.7 cm, the
surface area (SA) required is approximately 380 cm.sup.2. Using a
wall thickness of 0.06 cm, the minimum amount material of titanium
required is 101 g titanium (calculated as areathicknessdensity).
However, certain areas of the club need to be substantially thicker
than the minimum wall thickness for a variety of reasons. One such
area is the face 11. Variable face thicknesses are typical in
modern drivers, with thicknesses ranging from about 0.2 cm near the
outer periphery and up to 0.4 cm or more in the central region.
Most face areas do not approach the Rule limit of 12.7 cm (5
in).times.7.1 cm (2.8 in), which represents a SA of 90 cm.sup.2.
Certain drivers manufactured by Cobra Golf have a large face area,
measuring around 54 cm2. Assuming for calculation purposes that a
uniform thickness of 0.28 cm is used for the face to achieve its
functional requirements, then 67 g of titanium is needed for the
face. Thus the total amount of titanium used is:
Total amount = face mass + body mass = ( face SA face thickness
density ) + [ ( body SA - face SA ) body thickness density ] = ( 54
cm 2 0.28 cm 4.43 g / cm 3 ) + [ ( 380 cm 2 - 54 cm 2 ) 0.06 cm
4.43 g / cm 3 ] = 67 g + 86.6 g = 153.6 g ##EQU00001##
[0093] For current driver club building specifications having a
shaft length of 45.5 in, the overall club head mass is about 200 g.
The amount of free mass is thus 46.4 g to optimize certain playing
characteristics. Furthermore, the maximum shaft length allowed by
the Rules is 48 in, and when shafts are lengthened the heads
traditionally become lighter. A rule of thumb is that for every 0.5
in shaft length increase, the head mass must decrease by 5 g. Thus,
with a 48 in. shaft, the maximum mass for the club head is 175 g,
leaving little discretionary mass for the club head designer to
manipulate.
[0094] Increasing the face area to the maximum allowable value
enhances the playability of the resulting golf club, but presents
additional challenges to the club head designer. Namely, the
inventive golf club head is contoured to control the club head
attributes and volume, which increases the club head body SA. At
the same time, the face thickness would most likely need to be
increased to maintain its functional requirements. For quick
calculations, the following assumptions are made: face SA=76
cm.sup.2, face thickness=0.34 cm, body SA=400 cm.sup.2, and body
thickness=0.06 cm. This results in a club head mass of 200 g,
virtually eliminating discretionary mass available to the club head
designer for strategically weighting the club head.
[0095] This suggests that there is a limit to how much surface area
of the club head can be provided in titanium. One aspect of the
instant invention is the use of lightweight metallic materials with
densities less than 4.0 g/cc as the primary or only (including
alloys) material for both the face and body in heads with large
volumes (i.e., greater than 400 cc), large overall surface areas
(i.e., greater than 350 cm.sup.2), large face areas (i.e., greater
than 60 cm.sup.2), and plan profiles approaching the Rule limits
(12.7 cm heel-toe distance, less than 12.7 cm face-back distance).
As used herein, plan profile means the smallest rectangle that can
be drawn around the widest toe-heel and front-back dimensions of
the club head projected onto a plane. The plan profile defines a
side wall ratio, which is defined as the widest toe-heel dimension
divided by the widest front-back dimension. Preferably, the club
head has a plan profile area of at least 130 cm.sup.2, and more
preferably at least 145 cm.sup.2. The inventive club, having these
dimensions and materials, has increased forgiveness and increased
playability for golfers of various skill levels.
[0096] Preferred materials for the inventive club head include
aluminum, its alloys, metal matrix aluminum composites, aluminum
cermets (ceramic-reinforced metals), and the like. Such materials
may have material strengths that are comparable to the widely used
titanium alloys. Use of such materials have a density less than 3
g/cc, yielding a lower total club head mass even with increased
wall thicknesses. For example, using such an aluminum-based
material having a density of 2.8 to form the body and face of a
golf club head having an overall surface area of 400 cm.sup.2, the
face having a surface area of 76 cm.sup.2 and a thickness of 0.4
cm, and the body having a thickness of 0.1 cm, the total club head
mass is about 175.8 g. This represents a "savings" of more than 24
g relative a titanium-based club head. The club head designer may
use this saved mass to strategically position weight members to the
club head, increasing the club head MOI, lowering the club head CG,
and enhancing the forgiveness and playability of the resulting golf
club.
[0097] In an alternate version of the inventive club head, a
combination of a relatively heavier material and a lightweight
material is used to form the club head body. FIG. 13 shows an
exploded top view of a golf club head 200 of the present invention.
The club head 200 includes a body formed of two major components. A
first component 210 is formed of a relatively heavier material,
preferably a metallic material, and includes the strike face 11,
which may be an insert or formed integrally therewith. The metallic
component 210 further includes wing-like projections 211, 212
extending rearward from toe and heel portions of the face 11,
respectively, partially forming the skirt 14 of the club head 200.
The wing extensions 211, 212 define voids therebetween, including
in crown and sole portions of the club head. Thus, the metallic
component 210 has a frame-like design.
[0098] A second major component 220 is formed of a lightweight
material and cooperates with the metallic component 210 to define
the club head 200. Preferred materials for the second component 220
include reinforced plastic and other composites. The first and
second components 210, 220 are coupled together in known manner,
such as through an adhesive, epoxy, or the like. The components
210, 220 can also be coupled via bladder molding or welding. To
facilitate their attachment, the components 210, 220 have
corresponding attachment surfaces. Preferably, at least the top,
outer surfaces of the projections 211, 212 and corresponding
surfaces of the lightweight component 220 are such attachment
surfaces. Preferably, at least portions of the bottom, outer
surfaces of the projections 211, 212 and corresponding surfaces of
the lightweight component 220 are also attachment surfaces.
[0099] The lightweight component 220 fills in the voids of the
metallic component 210. Thus, the lightweight component forms a
majority of the crown 13, a rear portion of the skirt 14, and a
central portion of the sole 12. This is illustrated in FIG. 14,
which shows an exploded side view of the club head 200. By
displacing the denser metallic material from the crown, the center
of gravity is inherently lowered. Similarly, by displacing the
metallic material from the central portion of the sole 13, mass is
inherently biased toward the heel and toe of the club head.
[0100] Similarly to the second body member 102 discussed above, the
club head 200 may further include additional lightweight bodies 230
positioned in front heel and toe portions of the skirt 14, near the
strike face 11. Inclusion of such additional lightweight components
displaces further metallic material, further allowing the club
designer to enhance the playing characteristics of the golf
club.
[0101] One way to characterize the relative amounts of each
material is by a ratio of the surface area comprised by the
relatively heavier material and that comprised by the lightweight
material. It should be noted that, preferably, the "relatively
heavier material" is less dense than the metallic materials
typically used to form golf club heads. The aluminum materials
discussed above are preferred for the "heavy" material, and carbon
fiber or otherwise reinforced plastic composites are preferred for
the lightweight material. The surface area ratio may be compared
with a ratio of the densities of the two club head components 210,
220. According to one preferred arrangement,
A 2 A 1 < .rho. 1 .rho. 2 < 5 A 2 A 1 , ##EQU00002##
where A.sub.1 is the surface area of the first component 210,
A.sub.2 is the surface area of the second component 220, .rho.1 is
the density of the first component 210, and .rho.2 is the density
of the second component 220. It is the outer surface areas that are
being referred to here. More preferably,
A 2 A 1 < .rho. 1 .rho. 2 < 3 A 2 A 1 . ##EQU00003##
[0102] Thus, the inventive club head 200 balances the amount of the
relatively heavier material (measured as a function of its surface
area) with the relative densities of the components 210, 200.
Preferably, the first density .rho.1 is less than or equal to 3.5,
and the first density .rho.1 divided by the second density .rho.2
is less than 2. The greater the difference in relative densities,
the greater is the difference in surface areas. This is an inverse
relationship, which an increase in the difference in densities
causing a decrease in the surface area comprised by the heavier
material.
[0103] In addition to the amounts of material present in the club
head, the present invention additionally controls the placement of
the different materials. This material placement aspect may be
quantified as a ratio of projected surface area to actual surface
area. That is, for a given portion of the club head, the outer
surface area of each component 210, 200 forming the club head is
projected onto a horizontal plane. FIGS. 15 and 16 illustrate this
concept. FIG. 15 shows the heavier first club head component 210.
The projected surface area 210a shown above the first club head
component 210 is a projection onto a horizontal plane of that
portion of the component 210 above the crown parting line of the
club head components 210, 220. The projected area 210b shown below
the first club head component 210 is a projection onto a horizontal
plane of that portion of the component 210 below the parting line.
The projected area for the first club head component 210 is the sum
of these partial projections 210a, 210b. The parting line is a
convenient location to use to separate the relative club head
"halves," though it is not the only such location available.
Similarly, FIG. 16 shows the lighter second club head component 220
with a first projected area 220a of that portion of the component
220 above the parting line and a second projected area 220b of that
portion of the component 220 below the parting line. The projected
area for the second club head component 220 is the sum of these
partial projections 220a, 220b.
[0104] Due to the contoured nature of the club head, the club head
body surface area is increased and the projected area is less than
the actual surface area. Preferably, the ratio of projected area
divided by actual area is 0.8 or less, and more preferably this
ratio is 0.7 or less.
[0105] The concept of equivalent density is useful in describing
the inventive club head 200. The equivalent density is calculated
as the density of the material forming each component as a
percentage of the surface area for the component relative the total
surface area:
.rho. eq = .rho. 1 A 1 + .rho. 2 A 2 A 1 + A 2 ##EQU00004##
where .rho..sub.eq is the equivalent density and the other terms
are as defined above.
[0106] Of course, equivalent density can be calculated for the
entire club head and for specific portions of the club head. FIG.
17 shows a top view of the club head 200 and its plan profile 250.
Two additional plan profiles 251, 252 are also shown, with all of
the plan profiles 250, 251, 252 having geometric centers that are
coincident. Plan profile 251 has an area equal to 90% of the first
plan profile 250 area, and plan profile 252 has an area equal to
80% of the first plan profile 250 area. Each of these secondary
plan profiles 251, 252 has the same side wall ratio as the primary
plan profile 250. Preferably, the inventive golf club head has an
equivalent density of less than 2 within the 80% plan profile 252.
Preferably, the inventive golf club head also has an equivalent
density of greater than 2 between the 90% plan profile 251 and the
primary plan profile 250. In another aspect of the present
invention, this equivalent density between the 90% plan profile 251
and the primary plan profile 250 is greater than 3, or greater than
4.
[0107] Table 2 below shows the attributes of one example of the
inventive golf club head 200 and a known golf club head:
TABLE-US-00002 TABLE 2 Example Comparative Main Body .rho. 2.7 4.43
SA 170 270 Lightweight insert .rho. 1.5 1.5 SA 290 110 Club Head SA
460 380 SA.sub.L/SA.sub.H 1.7 0.41 .rho..sub.H/.rho..sub.L 1.8
2.95
where density .rho. is in g/cm.sup.3, surface area SA is in
cm.sup.2, H designates the heavier material, and L designates the
lighter material. As shown, the properties of the inventive club
head are an improvement over known club heads.
[0108] The strike face 11 may be integral with or an insert
attached to the first component 210. If an insert, the strike face
may be formed of the same material as the first component 210.
Alternatively, the face insert may be formed of a different
material, such as titanium or a titanium alloy. Thus, the density
of the face may be greater than the density of any of the body
components.
[0109] More than one light-weight material can be used with the
inventive golf club head. These components may also be comprised of
layers of various light-weight materials. If so, the densities,
surface areas, and other attributes mentioned herein are of the
actual inserts used rather than just one of the various materials
used.
[0110] Additionally, the light-weight components of the club head
may be treated with a metallic coating to improve their wear
resistance. Other coatings may also be used. Preferably, the
coating is chosen such that it has only a minor impact, if any, on
the club head attributes.
[0111] As used herein, directional references such as rear, front,
lower, etc. are made with respect to the club head when grounded at
the address position. See, for example, FIG. 9. The direction
references are included to facilitate comprehension of the
inventive concepts disclosed herein, and should not be read or
interpreted as limiting.
[0112] Adjustable Inserts
[0113] Another way to alter the golf club head to maximize the
playability of the club is to maximize the dimensions. For example,
a club designer may desire to have the distance from the face to
the back (FB) set as close as possible to the distance from the
heel to the toe (HT). Without being bound to any particular theory,
it may not be desirable for FB to exceed HT.
[0114] While the current trend in golf club manufacturing is to
maximize the dimensions of the golf club to take advantage of the
various physical properties allowed by a larger club head, due to
manufacturing tolerances, it is not practical in terms of time,
labor, or expense to set the face to back (FB) distance near the
heel to toe (HT) distance. Thus, traditional methods of
manufacturing have set the target manufacturing level of the face
to back distance (FB) considerably less than the heel to toe
distance (HT), to remove the tolerance consideration.
[0115] However, the adjustable insert contemplated by the inventors
allows distance in the face-to-back direction to be maximized by
setting the target manufacturing level sufficiently below the HT
distance to remove the tolerance considerations while providing a
means for adjusting the overall length from face-to-back to
approach HT distance. In addition, positioning the insert at the
rear of the club and constructing at least a portion of the insert
out of a high specific gravity material serves to move the center
of gravity of the club head away from the face.
[0116] The relationship between the distance from the face to the
back of the club head with the insert at its maximum extension
(MFB) to the distance from the heel to the toe (HT) may be
described by the following equations:
MFB.gtoreq.HT*1.10 1)
MFB.gtoreq.HT*1.05 2)
MFB.gtoreq.HT*1.00 3)
[0117] By allowing for the MFB to be greater than the HT, the
player is ensured that the club head will have the ability to reach
the HT distance. The player may then adjust the insert to ensure
that the HT is greater than the MFB, if so desired.
[0118] In the alternative, adjustability of the insert may be
expressed as a relationship between the distance from the face to
the back of the club head with no insert (XFB) to the distance from
the face to the back of the club head with the insert at its
maximum extension (MFB). For example:
MFB.gtoreq.XFB*1.50 4)
MFB.gtoreq.XFB*1.25 5)
MFB.gtoreq.XFB*1.10 6)
MFB.gtoreq.XFB*1.05 7)
[0119] FIGS. 18-21 illustrate various adjustable inserts according
to the invention. For example, golf club head 300 is comprised of a
face 321, a back 320, a heel 345, a crown 336, an adjustable insert
325, an adjustment mechanism 328, a locking mechanism 330, and a
sole 338. In particular, FIGS. 18-19 demonstrate a weight insert
325 coupled to golf club head 300. Insert 325 is attached to golf
club head 300 by way of adjustment mechanism 328 and locking
mechanism 330. In the unlocked position, the insert 325 is capable
of movement in the several directions. For example, the insert 325
may be adjusted in a direction from face to back. In the
alternative (or in addition to this adjustment), the insert 325 may
be adjusted vertically from crown to sole. In the locked position,
the insert is incapable of movement.
[0120] Insert 325 may be composed of a single material or a
combination of multiple materials. In one embodiment, at least a
portion of the insert is composed of a material with a higher
specific gravity than the material of the body. For example, the
specific gravity of all or a portion of the insert may be about 5
or more, preferably about 7 or more, and more preferably about 9 or
more. In comparison to the specific gravity of the body components,
the specific gravity of at least a portion of the insert may be
greater than the specific gravity of the body by about 4 or more,
preferably by about 5 or more, and even more preferably by about 7
or more.
[0121] In one embodiment, the portion of the insert with a higher
specific gravity may be less than about 50 percent of the total
volume of the insert. In another embodiment, the high specific
gravity portion is less than about 40 percent of the total volume
of the insert. In still another embodiment, the high specific
gravity portion accounts for less than about 20 percent of the
total volume of the insert. In the alternative, the insert in its
entirety may have a specific gravity that exceeds that of the
specific gravity of the body.
[0122] In one embodiment, the portion of the insert with a higher
specific gravity than the body is aligned with the horizontal
center of the club face when the club is at an address position. In
another embodiment, the high specific gravity portion may be biased
toward either the toe or the heel of the club head. Biasing the
high specific gravity portion toward either the heel or the toe
allows for a golfer with a hook or slice swing to obtain a center
of gravity of the club head that will accommodate the golfer's
swing.
[0123] Suitable materials for the high specific gravity portion of
the insert include, but are not limited to, tungsten and alloys
thereof, tungsten loaded polymer, nickel, copper, steel, gold,
platinum, depleted uranium, and combinations thereof.
[0124] Alternatively, the insert 325 or at least a portion of the
insert 325 may be composed of a low specific gravity material. In
this aspect of the invention, the specific gravity of at least a
portion of the insert is equal to or less than the specific gravity
of the body. For example, the specific gravity of all or a portion
of the insert may be less than about 4, preferably less than about
3, and more preferably less than about 1.5.
[0125] In one embodiment, the portion of the insert with a low
specific gravity may be less than about 40 percent of the total
volume of the insert. In another embodiment, the low specific
gravity portion is less than about 30 percent of the total volume
of the insert. In yet another embodiment, the low specific gravity
portion makes less than about 20 percent of the total volume of the
insert.
[0126] The portion of the insert with a low specific gravity may be
aligned with the horizontal center of the club face when the club
is at an address position. In another embodiment, the low specific
gravity portion may be biased toward either the toe or the heel of
the club head.
[0127] Suitable materials for the low specific gravity portion of
the insert include, but are not limited to, aluminum, aluminum
alloys, magnesium, magnesium alloys, thermoplastics, thermosets,
resins, epoxies, bulk molding compound, BMC material, or similar
materials and combinations thereof.
The Adjustment Mechanism
[0128] The adjustment mechanism 328 may take a plurality of forms.
For example, while not shown in detail, the adjustment mechanism
328 may be in the form of a series of notches at a receiving point
on the body of club head 300 and deformable tabs that are located
on the insert 325. Applying force to the insert 325 in the back to
face direction causes the tabs to undergo elastic deformation when
they come into contact with a notch. As the tab passes a notch the
tab returns to its original shape, and the insert is successfully
relocated closer to the face. A similar process ensues when the
insert is pulled in the face to back direction, resulting in the
insert relocated further from the face.
[0129] The adjustment mechanism 328 may also be in the form of a
series of telescoping steps housed on the interior of the club head
300. For example, when insert 325 is compressed or pulled, the
steps act similar to sections of a telescope, sliding past the next
step allowing for the extension and compression of the insert in
the face to back direction. The steps may be immobilized by a
locking mechanism when insert 325 is at a desired location.
[0130] In another embodiment, adjustment mechanism 328 takes the
form of a track and roller combination. For example, insert 325 may
be coupled to a roller that is, in turn, located on a track. When
the locking mechanism is disengaged, the golfer may simply slide
insert 325 in toward the face or pull insert 325 away from the face
to achieve the desired dimensions.
[0131] In still another embodiment, adjustment mechanism 328 may
take the form of a receiving member located inside the club head
and an elastically deformable portion of insert 325 folds similar
to an accordion. When compressed, the accordion portion folds in on
itself at regular intervals allowing insert 325 to move toward the
face. When pulled, the deformable portion stretches to allow for
insert 25 to move away from the face. In this aspect, the
deformable portion may include less than about 10 percent of the
total volume of insert 25. For example, in one embodiment, the
deformable portion accounts for less than about 5 percent of the
total volume of insert 325.
[0132] In yet another embodiment of the invention, the insert 325
may have a section that is elastically deformable. This deformable
section engages a receiving portion on the club head that is
tapered toward the face. Applying pressure from the back of the
club toward the face results in the deformable section of the
insert squeezing into the tapered section of the groove, and the
insert is moved toward the face. Locking mechanism 330 keeps the
deformable section from expanding back to its original length.
Removing or loosening the locking mechanism allows for the
deformable section to expand toward its original form, pushing the
insert away from the face.
[0133] In another embodiment, one or more screws or other movement
limiting fasteners may be used to adjust insert 325. For example, a
screw may be received by a receiving member located inside the club
head. Tightening the screw pulls the insert closer to the face.
Alternatively, loosening the screw moves insert 325 further from
the face. This adjustment mechanism has the added benefit of not
requiring a locking mechanism.
[0134] In another embodiment shown in FIGS. 22-24, insert 325 is
coupled to a center pin 350. The insert is preferably round and
capable of rotation about center pin 350. Center pin 350 may be
coupled to track 360 or similar device that allows for mobility in
the face to back dimension. The track may have a locking mechanism,
such as a set screw, that prevents the center pin from moving.
[0135] As shown in FIG. 23, insert 325 is made up of a portion 325a
and portion 325b, where the portions 325a and 325b have different
specific gravities. For example, 325a may have a higher specific
gravity than the remainder of the insert and, more specifically,
portion 325b. In addition, 325a may have a higher specific gravity
than the body of the club head. The low specific gravity portion
may account for at least about 50 percent of the total volume of
the insert. In one embodiment, the low specific gravity portion
makes up at least about 75 percent of the total volume of the
insert. The low specific gravity portion 325b may have has a
specific gravity of less than about 4, preferably less than about
3, and more preferably less than about 2. In this aspect of the
invention, the high specific gravity portion 325a has a specific
gravity greater than about 5, preferably greater than about 7, and
most preferably greater than about 9. The golfer may rotate the
insert to position the high specific gravity portion as
desired.
[0136] In the alternative, the insert 325 is made up of a portion
325a and portion 325b, where the portion 325a has a lower specific
gravity than the remainder of the insert and, more specifically,
portion 325b. In addition, 325a may have a lower specific gravity
than the body of the club head. The low specific gravity portion
325a may account for about 30 percent or less of the total volume
of the insert. In one embodiment, the low specific gravity portion
makes up at least about 20 percent of the total volume of the
insert. The low specific gravity portion 325a may have has a
specific gravity of less than about 4, preferably less than about
3, and more preferably less than about 2. In this aspect of the
invention, the high specific gravity portion 325b has a specific
gravity greater than about 7, preferably greater than about 9. The
golfer may rotate the insert to position the low specific gravity
portion as desired.
[0137] In another embodiment, shown generally in FIG. 25, two
separate movable inserts may be coupled to the body by a rotatable
hinge. For example, FIG. 25 shows inserts 375a and 375b attached to
the inside of the body of the club 300 by hinges 380a and 380b. The
hinge is lockable by the use of a locking mechanism such as a screw
or other movement limiting fastener. Inserts 375a and 375b are able
to move into the body of the club as desired by the golfer along
the axis of hinge 380a and 380b. Dotted lines 390a and 390b
indicate the position of the inserts 375a and 375b when fully
compressed into the body.
[0138] In still another embodiment, insert 325 is removable. In
this embodiment, the golfer is free to choose an insert
configuration that conforms to his swing type. For example, a
golfer may not wish to have a weighted insert, but would still
prefer the option of maximizing the front to back dimension of the
club head. In this aspect of the invention, the golfer would be
able to select an insert formed solely from a low specific gravity
material to allow for the maximization without adding significant
weight to any part of the club. In another embodiment, the golfer
may desire an insert with a particular mass distribution. For
example, inserts may be weighted toward the heel or the toe.
[0139] The adjustable insert may be capable of a wide range of
movement. For example, in one aspect of the invention the insert is
capable of movement in less than about 0.05 inch increments. In
another embodiment the insert is capable of movement in less than
about 0.01 inch increments. The ability to move the insert in small
increments allows the user to reach a target front to back distance
with a higher precision.
The Locking Mechanism
[0140] Like the adjustment mechanism, locking mechanism 330 may
take a variety of forms. For example, the locking mechanism may
take the form of a screw. In this aspect of the invention, when the
screw is turned in the particular direction, e.g., clockwise, it
may act as a barrier to prevent the adjustment mechanism from
moving.
[0141] In another embodiment, the locking mechanism may take the
form of a peg that, when inserted into the adjustment mechanism,
prevents movement of the adjustment mechanism. One of ordinary
skill in the art would appreciate that there are many methods for
preventing the movement of the adjustment mechanism that would be
sufficient for use with the adjustable insert of the present
invention. For example, screws, pegs, pins, clips, and other
similar adjustable fasteners are all useful as locking
mechanisms.
[0142] Preferably, the locking mechanism is accessed at a point on
the bottom of the club to preserve the aesthetic quality of the
club. Additionally, the locking mechanism may only be engaged
through the use of a specialized tool designed specifically for use
with the locking mechanism.
Spray Coating
[0143] As an alternative to or in combination with the weighted
inserts and adjustable inserts above, any portion of the club head
of the invention may be treated with a thermal or combustion spray
coating to alter the weight distribution of the club head.
[0144] For example, certain designated portions of the golf club
designed to have a high specific gravity may be spray coating
according to this aspect of the invention. Examples of suitable
materials for the spray include, but are not limited to,
aluminum-oxide powders, tungsten-carbide powders, molybdenum based
powder, tungsten powders, or similar materials and combinations
thereof. In addition, various portions of the club head may have a
spray coating from a first material and other various portions with
a second material. The spray coating may be applied such that there
are at least three portions of the club head sprayed with different
coatings.
[0145] The spray coatings may include propellants as needed to
disperse the materials with high specific gravity. The propellants
may be compressed air or other gasses. In other instances, the
coatings may be applied with electrospray. The spray coatings may
include an adhesive component or the spray coatings may include a
binder (vehicle) such as an alkyd, acrylic, vinyl-acrylics, vinyl
acetate/ethylene (VAE), polyurethane, polyester, melamine, or epoxy
(epoxide). In some instances, the spray coating will be air-cured,
however the coatings could be cured with heat or with UV.
[0146] The specific gravity of the spray coating may be at least
about 7. In one embodiment, the specific gravity of the spray
coating is greater than about 9. In another embodiment, the
specific gravity of the spray coating is greater than about 12.
[0147] The portions of the club head that are spray coated may be
sprayed prior to assembly, after partial assembly, or post
assembly. For example, the spray coating may be applied only to the
interior of the club head. As such, if the club head is formed from
multiple components, as described above, the various components may
be spray coated in certain areas prior to assembly. Likewise, if
the interior of the club head remains accessible after assembly of
most of the components, the spray coating may occur prior to the
remainder of the assembly. The spray coating may also be applied to
select exterior portions of the club head. For example, the
interior or exterior of the skirt of the club may have one or more
pockets, depressions, or cavities. A spray coating may be employed
to fill the pockets, depressions, or cavities. In one embodiment,
portions of the sole, toe and heel of the club head are sprayed
with a coating in order to increase the forgiveness of the club
head. In another embodiment, a spray coating is applied to the
entire exterior of the club head. Alternatively, the spray coating
may be applied to the entire interior of the club head. A spray
coating may also be applied to every surface of the club except for
the face of the club.
[0148] In an embodiment, a club head, for example a driver head,
may be designed with removable elements that allow access to the
interior of the head at a later time. As shown in FIG. 26, a club
head 400 can be constructed with removable elements, such as a face
plate 410. Access to the interior of the body 420 can be gained by
removing screws 430, however other methods of releaseably attaching
an element of the club to gain post-production access may also be
used. For example, the club heads shown in FIGS. 13-16 allow access
to the interior space of the club head. Other methods may include a
two-piece body that parts at an equator that runs from the crown to
the sole (not shown) or a removable sole, or a portion of the sole,
with press-fittings or tabs. In the embodiment shown in FIG. 26,
once the face plate 410 is removed from the body 420, it is
possible to access the interior 440.
[0149] As shown in FIG. 27, once the interior 440 is accessible, it
is possible to change the weight distribution of the club head by
distributing a high-specific gravity composition, such as a spray
coating described above. For example, the interior 440, or portions
of the interior 440 may be coated with a tungsten-containing spray
coating 450. As shown in FIG. 28, the coating may be only sprayed
on the lower interior surfaces of the club head, allowing the
center of gravity to be lowered in the club head. Alternatively,
the coating may only be sprayed on the toe-end interior surfaces,
thereby moving the center of gravity away from the hosel.
[0150] As described herein, spray coatings allow flexibility in
where the weight is placed in the head, and also provide
flexibility as to the amount of weight that is added. In contrast
to the moveable insert systems described above, the amount of
weight added with spray coatings is continuously variable. More
weight can be added by simply applying another layer of spray
coating. When combined with a removable element, such as faceplate
410, it is possible for a user or a golf professional to adjust the
center of gravity of the club head in order to better suit the
swing of the user. Additionally, the spray coating may be used to
"true-up" the weight of the club head either after manufacture or
after the club has been played for some time.
[0151] The spray coating may have a thickness ranging from about 10
microns to about 10 mm. In one embodiment, the spray coating is
about 0.01 mm to about 5 mm. In another embodiment, the spray
coating is about 0.02 mm to about 4 mm. In still another
embodiment, the spray coating is about 0.04 mm to about 2 mm. In
addition, various portions of the club head may have a spray
coating with a first thickness and other various portions with a
second thickness. The spray coating may be applied such that there
are at least three portions of the interior of the club head with
different thicknesses ranging from about 10 microns to about 10
mm.
High-Specific Gravity Conformable Materials
[0152] As an alternative to or in combination with the weighted
inserts, adjustable inserts, and spray coatings described above,
gels, putties, epoxies, caulk, and glues having high-specific
gravity may be used to alter the weight distribution of the club
head. These formulations are referred to generally as conformable
materials because they conform to the contours of the space that
they are placed into spontaneously, or with manipulation by a user.
The specific gravity of the conformable materials may be at least
about 4, e.g., at least about 7. In one embodiment, the specific
gravity of the conformable material is greater than about 9. In
another embodiment, the specific gravity of the conformable
material is greater than about 12.
[0153] These materials may be added to the interior or the exterior
of the club head in order to change the center of gravity of the
club head or to change the total weight of the club head. The
materials may be shapeable, such as putties, or the materials may
begin as a liquid and harden into a solid, such as epoxies and
glues. As shown in FIGS. 29 and 30, a conformable material 470 may
be placed in the interior 440 of the body 420 of a club head,
thereby altering the center of mass of the club head 400. The
conformable material 470 may be pressed into an interior corner of
the body 420, or the conformable material may be distributed along
a surface of the body 420, for example the sole. Because the
conformable material is sticky, it binds to the interior surface
and remains in place even with regular striking of the head
400.
[0154] In an alternative embodiment, the conformable material may
be a high specific-gravity liquid that cures into a solid. For
example a two-part epoxy can be infused with tungsten filings and
then poured into a club head, for example the club head shown in
FIG. 26. By placing the club head in the correct orientation during
the curing process, the weight may be placed in the optimum
location to affect the center of gravity. For example, the epoxy
can be allowed to pool in the lower portion of the interior of the
club head, thereby moving the center of gravity down. An epoxy may
comprise and epoxide resin and a polyamine hardener. The specific
gravity of the modified epoxy may be at least about 4, e.g., at
least about 7. In one embodiment, the specific gravity of the
modified epoxy is greater than about 9. In other embodiments, the
modified epoxy may contain granules of high specific-gravity
materials, such as powders or shot.
[0155] As mentioned previously, adhesives are known to be used to
"true-up" the swing weight of a club and also to retain any debris
that may be left in the club head during fabrication. Unlike the
known adhesives, however, the specialty high-specific gravity
polymer compositions of the invention allow precise and removable
placement of weight within the club head. In some instances, this
feature will allow for a club to be rebalanced after fabrication to
achieve a more desirable center of gravity, or to compensate for
small errors in the fabrication process that have left the club
head with a less-than-optimal center of gravity.
[0156] High specific-gravity adhesives may be delivered through a
port in a club head after the head has been fabricated, as shown in
FIGS. 31 and 32. For example, as shown in FIG. 31 a high
specific-gravity adhesive can be injected into a club head 500
through a port 510 using a squeeze bottle 530 with a direction
applicator 535. Because of the direction applicator 535, it is
possible to carefully direct the high specific-gravity adhesive to
the desired location inside the club head, for example a corner of
the club furthest from the face and hosel.
[0157] In some clubs, such as shown in FIGS. 31 and 32, the club
head may have interior indexed depressions 540 that allow a trained
user, for example a golf professional or a club fitter, to locate a
specific location in the interior of the club head. Using the
direction applicator 535 it is possible to "feel" the interior
walls of the club head and then count indexed depressions to assure
that the adhesive is placed in the desired position in order to
improve the performance of the club. The indexed depressions 540
may be cast or forged into the head during fabrication or the
indexed depressions 540 may be cut into the head during
fabrication. The indexed depressions 540 may be placed throughout
the interior of the club, however they will often be fabricated
into the sole of the club. The indexed depressions 540 may be
overlayed to provide specific volumes to fill with adhesives, e.g.,
1 cc, then 2 cc, then 4 cc. Because the specific gravity of the
adhesive is measurable, it will be possible to know the volume
filled for a given weight change and vice-versa. Once the adhesive
has cured, it will form an indexed weighted portion 550.
[0158] The adhesive may be applied to a club in which the interior
is directly accessible, such as shown in FIG. 26. However, port
access will provide certain advantages in that the club will be
structurally unchanged after the process is complete. That is,
there will not be concerns about the relationship between the
various club angles which may be disrupted when the club head is
disassembled and re-assembled.
[0159] Kits for modifying the center of gravity of a golf club head
are also disclosed. Such kits may include instructions for
assessing if, by how much, and in which direction, the center of
gravity of the club head should be adjusted. The instructions may
teach how to disassemble a club head, e.g., a club head shown in
FIG. 26, in order to access an interior of the club head to add or
remove a weighted material. In some embodiments, the kit may
include a specialized tool, e.g., a star-shaped driver, to remove a
fastener that allows a portion of the club head to be removed to
give access to the interior. In other embodiments, the kit may
include instructions and a polymer composition comprising a metal,
to be used in adjusting the center of gravity of the club head.
[0160] The instructions for modifying the center of gravity of a
golf club head need not be in a written format. The instructions
may comprise an audio or video recording, a podcast, or cartoon
explaining how to modify the center of gravity of a golf club head.
The instructions may provide directions for accessing content
relevant to modifying the center of gravity of a golf club head
over a network, e.g., over the internet or with a smart phone. The
instructions may include tutorials for disassembling a golf club
head, reassembling a golf club head, inserting a high specific
gravity material, removing a high specific gravity material,
evaluating the weight of a golf club or a golf club head, or
evaluating the trajectory of a golf ball to determine how to modify
the center of gravity of a golf club head. In some embodiments, the
instructions are written and include pictures.
[0161] In some embodiments, the kit will additionally include a
golf club, having a club head. In some embodiments, the kit will
include a golf club head. In some embodiments, the kit will be a
set of a type of golf club heads, e.g., drivers, fairway woods,
hybrids, irons, putters, etc. In some embodiments, the kit will be
a set of a type of golf clubs, e.g., drivers, fairway woods,
hybrids, irons, etc. In some embodiments, the kit will comprise a
plurality of high specific gravity materials that may be placed in
or on the club to modify the center of gravity.
[0162] Other than in the operating examples, or unless otherwise
expressly specified, all of the numerical ranges, amounts, values
and percentages such as those for amounts of materials, moments of
inertias, center of gravity locations, loft and draft angles, and
others in the following portion of the specification may be read as
if prefaced by the word "about" even though the term "about" may
not expressly appear with the value, amount, or range. Accordingly,
unless indicated to the contrary, the numerical parameters set
forth in the following 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.
[0163] 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.
[0164] While the preferred embodiments of the present invention
have been described above, it should be understood that they have
been presented by way of example only, and not of limitation. It
will be apparent to persons skilled in the relevant art that
various changes in form and detail can be made therein without
departing from the spirit and scope of the invention. Thus the
present invention should not be limited by the above-described
exemplary embodiments, but should be defined only in accordance
with the following claims and their equivalents. Furthermore, while
certain advantages of the invention have been described herein, it
is to be understood that not necessarily all such advantages may be
achieved in accordance with any particular embodiment of the
invention. Thus, for example, those skilled in the art will
recognize that the invention may be embodied or carried out in a
manner that achieves or optimizes one advantage or group of
advantages as taught herein without necessarily achieving other
advantages as may be taught or suggested herein. U.S. Design Pat.
No. D567,888, is incorporated herein by reference.
* * * * *