U.S. patent application number 11/284769 was filed with the patent office on 2006-09-21 for shaft for use in golf clubs and other shaft-based instruments and method of making the same.
Invention is credited to Michael H.L. Cheng.
Application Number | 20060211511 11/284769 |
Document ID | / |
Family ID | 25163266 |
Filed Date | 2006-09-21 |
United States Patent
Application |
20060211511 |
Kind Code |
A1 |
Cheng; Michael H.L. |
September 21, 2006 |
Shaft for use in golf clubs and other shaft-based instruments and
method of making the same
Abstract
A shaft for use in a golf-club or other shaft-based instrument,
including a base member and a metal layer, and a method of making
the same.
Inventors: |
Cheng; Michael H.L.; (Simi
Valley, CA) |
Correspondence
Address: |
HENRICKS SLAVIN AND HOLMES LLP;SUITE 200
840 APOLLO STREET
EL SEGUNDO
CA
90245
US
|
Family ID: |
25163266 |
Appl. No.: |
11/284769 |
Filed: |
November 22, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10998298 |
Nov 26, 2004 |
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11284769 |
Nov 22, 2005 |
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09794657 |
Feb 28, 2001 |
6908401 |
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10998298 |
Nov 26, 2004 |
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Current U.S.
Class: |
473/316 ;
473/319; 473/320; 473/321 |
Current CPC
Class: |
A63B 60/06 20151001;
A63B 60/52 20151001; A63B 2209/023 20130101; A63B 53/10 20130101;
A63B 2209/02 20130101; A63B 60/08 20151001; A63B 53/12 20130101;
A63B 60/10 20151001 |
Class at
Publication: |
473/316 ;
473/319; 473/320; 473/321 |
International
Class: |
A63B 53/12 20060101
A63B053/12; A63B 53/10 20060101 A63B053/10 |
Claims
1-43. (canceled)
44. A golf club shaft for use with a golf club head including a
hosel having a predetermined length, the golf club shaft
comprising: a polymer base member defining a tip end, a tip section
adapted to be inserted into the hosel, a main body section, a grip
section, and a butt end; and a metal layer extending around and
secured to at least a portion of the base member and defining
distal and proximal ends and first and second longitudinally
extending side edges that abut one another.
45. A golf club shaft as claimed in claim 44, wherein the base
member comprises a plurality of resin layers.
46. A golf club shaft as claimed in claim 45, wherein the plurality
of resin layers comprises a plurality of fiber reinforced resin
layers.
47. A golf club shaft as claimed in claim 46, wherein the base
member defines a longitudinal axis and the plurality of fiber
reinforced resin layers include a group of layers with fibers
angled with respect to the longitudinal axis of the shaft and a
group of layers with fibers substantially parallel to the
longitudinal axis.
48. A golf club shaft as claimed in claim 44, wherein the metal
layer is located such that the distal end of the metal layer is
less than the predetermined length from the tip end and the
proximal end of the metal layer is greater than the predetermined
length from the tip end.
49. A golf club shaft as claimed in claim 48, wherein the distal
end of the metal layer is substantially aligned with the tip end of
the base member.
50. A golf club shaft as claimed in claim 48, wherein the metal
layer covers at least a portion of the tip section and at least a
portion of the main body section.
51. A golf club shaft as claimed in claim 48, wherein the metal
layer covers the entire tip section and at least a portion of the
main body section.
52. A golf club shaft as claimed in claim 44, wherein the metal
layer is secured to at least a portion of the tip section.
53. A golf club shaft as claimed in claim 52, wherein the metal
layer covers the entire tip section.
54. A golf club shaft as claimed in claim 44, wherein the tip
section defines a first shape and the main body section defines a
second shape different than the first shape.
55. A golf club shaft as claimed in claim 54, wherein the tip
section defines a cylindrical shape and the main body section
defines a frusto-conical shape.
56. A golf club shaft as claimed in claim 44, further comprising: a
bonding layer between the base member and the metal layer.
57. A golf club shaft as claimed in claim 56, further comprising:
an outer layer, including a resin and a cloth within the resin,
over the metal layer.
58. A golf club shaft as claimed in claim 44, further comprising:
an outer layer, including a resin and a cloth within the resin,
over the metal layer.
59. A golf club shaft as claimed in claim 44, wherein the
longitudinally extending side edges are linear from the proximal
end of the metal layer to the distal end of the metal layer.
60. A golf club shaft, comprising: a polymer base member defining a
circumference, a tip section, a main body section, and a grip
section; a bent metal sheet on at least a portion of the base
member that extends at least once around the circumference of the
portion of the base member; and an outer layer, formed from a fiber
reinforced resin or a resin with a cloth within the resin, covering
the bent metal sheet and extending beyond the bent metal sheet.
61. A golf club shaft as claimed in claim 60, wherein the tip
section defines a first shape and the main body section defines a
second shape different than the first shape.
62. A shaft as claimed in claim 60, further comprising: a bonding
layer between the base member and the bent metal sheet.
63. A golf club shaft as claimed in claim 60, wherein the polymer
base member comprises a plurality of fiber reinforced resin
layers.
64. A golf club shaft for use with a golf club head including a
hosel having a predetermined length, the golf club shaft
comprising: a polymer base member defining a tip end, a tip section
adapted to be inserted into the hosel, a main body section, a grip
section, and a butt end; and a metal layer secured to at least a
portion of the base member, defining distal and proximal ends and
first and second longitudinally extending side edges, and extending
around the portion of the base member such that a first portion of
the metal layer overlaps a second portion of the metal layer; and a
bonding layer between the polymer base member and metal and between
first and second portions of the metal layer.
65. A golf club shaft as claimed in claim 64, wherein the base
member comprises a plurality of resin layers.
66. A golf club shaft as claimed in claim 65, wherein the plurality
of resin layers comprises a plurality of fiber reinforced resin
layers.
67. A golf club shaft as claimed in claim 64, wherein the metal
layer is located such that the distal end of the metal layer is
less than the predetermined length from the tip end and the
proximal end of the metal layer is greater than the predetermined
length from the tip end.
68. A golf club shaft as claimed in claim 67, wherein the distal
end of the metal layer is substantially aligned with the tip end of
the base member.
69. A golf club shaft as claimed in claim 67, wherein the metal
layer covers at least a portion of the tip section and at least a
portion of the main body section.
70. A golf club shaft as claimed in claim 67, wherein the metal
layer covers the entire tip section and at least a portion of the
main body section.
71. A golf club shaft as claimed in claim 64, wherein the metal
layer is secured to at least a portion of the tip section.
72. A golf club shaft as claimed in claim 71, wherein the metal
layer covers the entire tip section.
73. A golf club shaft as claimed in claim 64, wherein the metal
layer extends exactly a whole number multiple of times around the
base member.
74. A golf club shaft as claimed in claim 73, wherein the metal
layer extends exactly two times around the base member.
75. A golf club shaft as claimed in claim 64, further comprising:
an outer layer, including a resin and a cloth within the resin,
over the metal layer.
76. A golf club shaft as claimed in claim 64, wherein the tip
section defines a first shape and the main body section defines a
second shape different than the first shape.
77. A golf club shaft as claimed in claim 76, wherein the tip
section defines a cylindrical shape and the main body section
defines a frusto-conical shape.
78. A golf club shaft as claimed in claim 64, wherein the first
portion of the metal layer continuously overlaps the second portion
of the metal layer from the distal end to the proximal end.
Description
BACKGROUND OF THE INVENTIONS
[0001] 1. Field of the Inventions
[0002] The present inventions relate generally to shaft-based
instruments and, more particularly, to shafts for use in golf clubs
and other shaft-based instruments.
[0003] 2. Description of the Related Art
[0004] Over the years, there have been a variety of attempts to
improve shaft-based instruments such as golf clubs, ski poles and
hockey sticks. With respect to golf clubs, many substitutes have
been introduced for the hard wood shafts originally used in golf
club drivers and irons. Early substitute materials included
stainless steel and aluminum. More recently, carbon fiber
reinforced resin shafts have become popular. Such shafts are
typically hollow and consist of a shaft wall formed around a
tapered mandrel. The use of fiber reinforced resin has allowed golf
club manufacturers to produce shafts having varying degrees of
strength, flexibility and torsional stiffness. Carbon fiber
reinforced resin shafts have also become popular in other
shaft-based instruments. As such, manufacturers are able to produce
shafts which suit the needs of a wide variety of applications.
[0005] Nevertheless, manufactures of shaft-based instruments are
faced with a variety of design issues that have proven difficult to
overcome using conventional fiber reinforced resin technologies.
One issue associated with shaft design is related to the torsional
and longitudinal stiffness of the shafts and, in the golf club
shaft context, the attempts of designers to increase torsional
stiffness (especially near the club head) in order to improve shot
accuracy and increase longitudinal stiffness in order to cope with
the ever increasing swing velocities of golfers. Another issue
associated with shaft design is the location of the shaft flex
point. More specifically, the inability of shaft designers to
precisely predict the location of the flex point when designing a
shaft without using excessive amounts of composite material, which
can lead to weight and thickness issues, can be problematic.
Breakage prevention is another important design issue. With respect
to golf club shafts, for example, breakage often occurs within the
region of the main body section that is adjacent to the club
head.
SUMMARY OF THE INVENTIONS
[0006] The general object of the present inventions is to provide
shafts that eliminate, for practical purposes, the aforementioned
problems. In particular, one object of the present inventions is to
provide golf club shafts and other shafts that have greater
torsional and longitudinal stiffness than conventional fiber
reinforced resin shafts. Another object of the present inventions
is to provide golf club shafts and other shafts which facilitate
precise location of the flex point. Still another object of the
present inventions is to provide golf club shafts and other shaft
that resist breakage.
[0007] In order to accomplish these and other objectives, a shaft
in accordance with the present invention includes a plurality of
fiber reinforced resin layers and a metal layer. The metal layer
may, for example, be formed from a lightweight, high modulus of
elasticity and tensile strength material such as titanium. Such a
shaft provides a number of advantages over conventional shafts. For
example, the metal layer augments the shafts torsional and
longitudinal stiffness. Shaft designers can also adjust the
location of the flex point by simply adjusting the length of the
metal layer. The metal layer will also prevent breakage. In golf
club shafts, for example, the metal layer may extend along the tip
section from a point within the club head hosel to a point outside
the hosel. This arrangement strengthens the area of the tip section
adjacent to the club head that is a frequent area of breakage in
conventional golf club shafts and also provides torsional
rigidity.
[0008] The above described and many other features and attendant
advantages of the present inventions will become apparent as the
inventions become better understood by reference to the following
detailed description when considered in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Detailed description of preferred embodiments of the
inventions will be made with reference to the accompanying
drawings.
[0010] FIG. 1 is a side view of a golf club in accordance with a
preferred embodiment of a present invention.
[0011] FIG. 2 is a section view taken along line 2-2 in FIG. 1.
[0012] FIG. 3 is a partial, exploded view of the portion of the
golf club shaft illustrated in FIG. 2.
[0013] FIG. 4 is a cutaway view of a portion of the golf club shaft
illustrated in FIG. 1 with various layers of the shaft cutaway by
different amounts to expose the layers.
[0014] FIG. 5a is a section view of the tip region of the golf club
illustrated in FIG. 1.
[0015] FIG. 5b is a plan view showing the relative sizes of the
metal layer and outer layer in the golf club illustrated in FIG.
5a.
[0016] FIG. 5c is a section view of the tip region of a golf club
in accordance with a preferred embodiment of a present
invention.
[0017] FIG. 5d is a section view of the tip region of a golf club
in accordance with a preferred embodiment of a present
invention.
[0018] FIG. 6 is a cutaway, partial section view of the golf club
shaft in accordance with a preferred embodiment of the present
invention.
[0019] FIG. 7 is perspective view of a pair of metal layer members
in accordance with a preferred embodiment of a present
invention.
[0020] FIG. 8 is a plan view of a metal layer blank in accordance
with a preferred embodiment of a present invention.
[0021] FIG. 9 is a perspective view of the metal layer formed by
the metal layer blank illustrated in FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] The following is a detailed description of the best
presently known modes of carrying out the inventions. This
description is not to be taken in a limiting sense, but is made
merely for the purpose of illustrating the general principles of
the inventions. The scope of the inventions is defined by the
appended claims. Additionally, although the present inventions are
described herein in the golf club shaft context because the
inventions are particularly well suited to golf club shafts, the
inventions are not so limited. The inventor herein has determined
that present inventions have application in other shaft-based
devices such as, for example, ski poles and hockey sticks.
[0023] As illustrated for example in FIG. 1, a golf club shaft 10
in accordance with a preferred embodiment of a present invention
includes a hollow shaft 12, a grip 14, and a club head 16. The
exemplary shaft 12 is divided into three sections--the grip section
18 which is covered by the grip 14, the tip section 20 which
supports the club head 16, and the main body section 22 which
extends from the distal end of the grip section to the proximal end
of the tip section. The tip section/main body section intersection
is identified by reference numeral 23. In the illustrated
embodiments, the grip section 18 is substantially cylindrical, the
tip section 20 is substantially cylindrical, and the main body
section 22 has a frusto-conical shape with a substantially constant
taper. The exemplary shaft 12 also includes a butt (or "proximal")
end 24 and a tip (or "distal") end 26. The present inventions are
not, however, limited to such a configuration. Other grip section,
tip section and main body section configurations and shapes, such
as those disclosed in commonly assigned U.S. Pat. Nos. 5,944,618
and 5,957,783, both of which are incorporated herein by reference,
may also be employed.
[0024] It should be noted that the dimensions of the shafts
illustrated in the drawings are exaggerated and often not to scale.
Commercial embodiments of golf club shafts in accordance with the
present inventions may range from about 33 inches to about 46
inches in overall length. With respect to the tip section 20, the
length may range from about 3 inches to about 8 inches and the
outer diameter (OD) may range from about 0.370 inch to about 0.500
inch for irons and from about 0.335 inch to about 0.500 inch for
woods. The typical club head hosel, i.e. the portion of the club
head that receives the shaft, is about 1 inch. Thus, the tip
section 20 will extend proximally beyond the hosel in the manner
illustrated in FIGS. 1 and 5a. The length of the grip section 18
may range from about 6 inches to about 10 inches. The exemplary
grip section may be either substantially cylindrical (as shown)
with an OD of about 0.58 inch to about 0.62 inch or tapered from an
OD of about 0.81 inch to about 1.0 inch at the butt to an OD of
about 0.55 inch to about 0.70 inch at the grip section/main body
section intersection. The wall thickness is preferably between
about 0.024 inch and about 0.059 inch (between about 0.6 mm and
about 1.5 mm).
[0025] The exemplary shaft 12 consists of two primary components--a
polymer base member 28 and a metal layer 30. Referring to FIGS.
2-4, the exemplary base member 28 is a fiber reinforced resin base
member that may be formed in conventional fashion by wrapping
multiple layers (typically 10-20 layers total) of a fiber
reinforced resin composite over a mandrel until the desired wall
thickness is obtained. The layers are preferably arranged in groups
that each include a plurality of fiber reinforced resin layers. In
the illustrated embodiment, layer groups 32, 34 and 36 are oriented
at different angles with respect to the longitudinal axis of the
shaft 12. The fibers within the respective layers of each group are
parallel to one another. More specifically, the fibers 32a and 34a
in the layers within groups 32 and 34 are angled from 30-90 degrees
with respect to the longitudinal axis of the shaft, while the
fibers 36a in layer group 36 are parallel to the longitudinal axis.
Other layer and layer group combinations may also be employed in
embodiments of the present invention. For example, layer groups 32
and 34 may be combined (a total of 5-10 layers, for example) and
the individual layers arranged such that the fibers in successive
layers are oriented at different angles with respect to the
longitudinal axis.
[0026] The exemplary base member 28 may be manufactured using any
of the materials typically used to produce composite resin/fiber
golf club shafts. Suitable resins include, for example,
thermosetting resins or polymers such as polyesters, epoxies,
phenolics, melamines, silicones, polimides, polyurethanes and
thermoplastics. Suitable fibers include, for example, carbon-based
fibers such as graphite, glass fibers, aramid fibers, and extended
chain polyethylene fibers. After the successive layers of fiber
reinforced resin are wrapped around the mandrel, the shaft is cured
in an oven. Curing times and temperatures depend on the polymer
used in the composite and are well known to those of skill in the
art.
[0027] The metal layer 30 in the exemplary embodiments is
preferably formed from a metal having relatively high tensile
strength (about 200-350 Mpa) and a relatively high modulus of
elasticity (about 70-200 GPa). Commercially pure titanium, 7000
series aluminum, and low alloy steel are suitable metals. Aluminum
alloys, such as scandium-aluminum alloys, that have the desired
tensile strength and modulus of elasticity characteristics may also
be used. The thickness of the metal layer 30 will range from about
0.001 inch to about 0.006 inch when formed from these materials.
Although not so limited, the metal layer will preferably be
positioned such that it extends along the shaft from a point on the
shaft within the club head hosel to a point on the shaft outside
the club head hosel. This is because the area adjacent to the club
head 16 is the area which is most effected by torsional forces and
is also the area where conventional shafts are most likely to
break. As illustrated in FIGS. 1 and 5a, the metal layer 30 in the
exemplary embodiment is aligned with tip end 26 and extends along
the tip section 20 to a point distal of the main body section
22.
[0028] The length of the metal layer 30 will depend upon the
dimensions of the overall shaft 12 and the intended shaft
characteristics, such as stiffness and flex point location.
Suitable lengths for golf club shafts range from about 5 inches to
about 30 inches. However, there may be some instances where the
metal layer 30 would extend over the entire length of the shaft.
There may also be some instances where the metal layer 30 would
extend over only a portion of the tip section 20 that will not be
within the club head hosel when the golf club is assembled (FIG.
5c), or would extend over only some or all of the main body section
22 (FIG. 5d), or would extend over only some or all of the tip
section and some or all of the main body section (FIG. 6),
depending on the intended results. With respect to shafts for other
shaft-base instruments, the metal layer may extend over the entire
length of the base member, or over only a portion thereof,
depending on the intended application.
[0029] The metal layer 30 is wrapped around the fiber reinforced
resin composite base member 28 through the use of a rolling process
during manufacturing. The rolling process may be performed by hand
or with a rolling table. The metal sheet (or sheets) that make up
the metal layer 30 should preferably be sized such that the metal
wraps exactly a whole number multiple of times around the base
member 28, e.g. exactly one time or exactly two times, but not 21/2
times, in order to prevent the formation of spines.
[0030] Preferably, there will be a bonding layer 38 that secures
the base member 28 and metal layer 30 to one another in the manner
illustrated for example in FIGS. 3 and 4. The bonding layer 38,
which has approximately the same measurements as the metal layer
30, can be formed from any suitable material. Suitable bonding
layers include, but are not limited to, high resin content scrim
cloth (about 40% resin content by weight or higher), a sheet of
epoxy, spray on epoxy, tacking film, and a layer of fiber
reinforced resin that is pre-impregnated with epoxy (about 40%
resin content or higher). The bonding layer 38 should be secured to
the metal layer 30 prior to wrapping the metal layer 30 around the
base member 28. The bond between the metal layer 30 and the bonding
layer 38 may be improved by roughening the surface of the metal
layer that is in contact with the bonding layer prior to adding the
bonding layer. This may be accomplished by, for example, chemical
etching, sand blasting, or brushing the surface of the metal sheet
(or sheets) used to form the metal layer 30.
[0031] The metal layer 30 may have enough metal memory to cause it
to unwind a bit after the rolling process. Thus, although not
required, the exemplary shaft 12 also includes an outer layer 40
that is used to hold down the metal layer 30. Suitable outer layers
include high resin content scrim cloth (about 40% resin content by
weight or higher) and fiber reinforced resin that is
pre-impregnated with epoxy (about 40% resin content or higher). The
scrim cloth is advantageous in that the metal layer 30 will be
visible through the scrim cloth. As shown in FIG. 5b, the outer
layer 40 extends at least slightly beyond the metal layer 30 on at
least two sides (e.g. at least 1/8 of an inch on two sides) in the
exemplary embodiment so that an adhesive regions 41a and 41b will
extend slightly beyond the metal layer 30. The adhesive region 41a
will bond to the base member 28 and the adhesive region 41b will
slightly overlap, and bond to, a portion of the outer layer 40. The
outer layer 40 may, alternatively, cover the entire base member 28
(FIG. 6) or may cover the metal layer and some, but not all of the
portion of the base member proximal of the metal layer.
[0032] Another suitable manufacturing technique is the bladder mold
process. Here, the fiber reinforced resin, metal, adhesive, outer
layers are prearranged and then wrapped together around a bladder
with a small mandrel inside the bladder. A heated mold is placed
over the wrapped bladder, the bladder is expanded to force the
material against the mold, and the shaft is then cured in the mold.
Curing times and temperatures depend on the polymer used in the
composite and are well known to those of skill in the art. Filament
winding techniques, where the process is stopped to change
materials, may also be used. No adhesive is required here because
the graphite tow is wet with epoxy or other adhesive.
[0033] As noted above, the tip section 20 is substantially
cylindrical, while the main body section 22 has a frusto-conical
shape with a substantially constant taper. In some embodiments,
such as that illustrated in FIG. 6, it may be desirable to extend
the metal layer 30 into the main body section 22. The inventor
herein has determined that the discontinuity of shape at the tip
section/main body section junction 23 can, in some instances, make
rolling the metal layer 30 onto the base member 28 difficult when
the metal layer is formed from a single, continuous sheet of metal.
One way to obviate this issue is to form the metal layer 30 from
two separate metal layer members. As illustrated for example in
FIG. 7, a metal layer 30' may be formed from a cylindrical metal
layer member 44 and a frusto-conical metal layer member 46 that are
arranged as close to one another as practicable in the assembled
shaft. The metal layer members 44 and 46 are formed from separate
sheets of metal that may be rolled onto the base member 28
separately or simultaneously.
[0034] The rolling issue may also be obviated by forming a metal
layer 30'' from a metal sheet (or "blank") 48 having a plurality of
longitudinally extending slits 50 formed therein in the manner
illustrated for example in FIGS. 8 and 9. The length of the slits
is 50 equal to the length of the portion of the metal layer within
the main body section 22 (assuming that the end of the metal layer
30'' opposite of the slits will be aligned with the tip end 26 of
the shaft 12). When the metal sheet 48 is wrapped around the base
member 28, the resulting metal layer 30''will include a cylindrical
metal layer member 52 and a series of longitudinally extending
metal layer members 54 that fan out from the cylindrical metal
layer member to form the frusto-conical portion of the metal layer.
The longitudinally extending slits 50 cause the formation of relief
areas 56 between adjacent metal layer members 54, which increase in
size as the distance from the cylindrical metal layer member 52
increases.
[0035] Although the present inventions have been described in terms
of the preferred embodiment above, numerous modifications and/or
additions to the above-described preferred embodiments would be
readily apparent to one skilled in the art. By way of example, but
not limitation, the present inventions include golf clubs including
any of the shafts described above. It is intended that the scope of
the present inventions extends to all such modifications and/or
additions and that the scope of the present inventions is limited
solely by the claims set forth below.
* * * * *