U.S. patent application number 13/115026 was filed with the patent office on 2011-12-01 for golf club by reverse interlaminar placement (rip) technology.
This patent application is currently assigned to ALDILA, INC.. Invention is credited to Kevin EGELHOFF.
Application Number | 20110294593 13/115026 |
Document ID | / |
Family ID | 45022572 |
Filed Date | 2011-12-01 |
United States Patent
Application |
20110294593 |
Kind Code |
A1 |
EGELHOFF; Kevin |
December 1, 2011 |
GOLF CLUB BY REVERSE INTERLAMINAR PLACEMENT (RIP) TECHNOLOGY
Abstract
A golf club shaft is formed having a flexural rigidity layer at
last one third the length of which is encased in an outer layer.
The shaft is formed by applying sheets of composite material to a
mandrel. Sheets forming the flexural rigidity layer include
unidirectional fibers oriented substantially in parallel with the
longitudinal axis of the shaft. The outer layer may include
composite material sheets each having unidirectional fibers
oriented at an angle with respect to the shaft's longitudinal axis.
An innermost layer of the shaft may be formed of composite material
sheets having fibers oriented at an angle with respect to the
shaft's longitudinal axis.
Inventors: |
EGELHOFF; Kevin; (Poway,
CA) |
Assignee: |
ALDILA, INC.
Poway
CA
|
Family ID: |
45022572 |
Appl. No.: |
13/115026 |
Filed: |
May 24, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61350446 |
Jun 1, 2010 |
|
|
|
Current U.S.
Class: |
473/319 ;
156/191; 156/192 |
Current CPC
Class: |
A63B 60/00 20151001;
A63B 60/08 20151001; A63B 2209/023 20130101; A63B 60/06 20151001;
A63B 60/10 20151001; B29L 2031/5227 20130101; B29C 70/30 20130101;
A63B 53/10 20130101; A63B 60/0081 20200801 |
Class at
Publication: |
473/319 ;
156/192; 156/191 |
International
Class: |
A63B 53/10 20060101
A63B053/10; B65H 81/06 20060101 B65H081/06 |
Claims
1. A golf club shaft, comprising: an elongated, generally tapered
shaft having a generally circular transverse cross-sectional shape,
the circular wall of the shaft including: at least one flexural
rigidity layer disposed around the entire length of the shaft,
reinforcement fibers of the flexural rigidity layer substantially
oriented in the longitudinal direction of the shaft, and an outer
layer, having no longitudinally-oriented fibers, disposed
concentrically about an outermost flexural rigidity layer and
extending at least one third the length of the shaft from a tip end
of the shaft.
2. The golf club shaft according to claim 1, wherein the outer
layer comprises at least one outer bias layer, each outer bias
layer having unidirectional reinforcement fibers angled with
respect to the shaft's longitudinal axis, the unidirectional
reinforcement fibers of each successive outer bias layer oriented
at a substantially equal but opposite angle with respect to the
orientation of fibers belonging to any adjacent outer bias
layer.
3. The golf club shaft according to claim 1 or claim 2, wherein the
at least one outer layer extends the entire length of the
shaft.
4. The golf club shaft according to claim 2, further comprising: at
least two inner bias layers alternatingly disposed beneath the
entire length of the innermost flexural rigidity layer, each inner
unidirectional bias layer having unidirectional fibers angled
complementarily to the fibers of the next of the inner
unidirectional bias layers with respect to the shaft axis and
disposed substantially from the tip end to the butt end of the
shaft.
5. The golf club shaft according to claim 3, further comprising: at
least two inner unidirectional bias layers alternatingly disposed,
for the entire length of the shaft, beneath an inner surface of the
innermost base unidirectional flex layer, each inner unidirectional
bias layer having unidirectional fibers angled complementarily to
the fibers of the next of the inner unidirectional bias layers with
respect to the shaft axis and disposed substantially from the tip
end to the butt end of the shaft.
6. The golf club shaft according to claim 2, wherein the
unidirectional fibers of the outer unidirectional bias layers are
oriented between about +35.degree. and +55.degree. or between about
-35.degree. and -55.degree. with respect to the longitudinal axis
of the shaft such that the fibers of one outer unidirectional bias
layer are oriented at a substantially equal but opposite angle with
respect to the orientation of fibers belonging to the next outer
unidirectional bias layer.
7. The golf club shaft according to claim 4, wherein the
unidirectional fibers of the inner unidirectional bias layers are
oriented between about +35.degree. and +55.degree. or between about
-35.degree. and -55.degree. with respect to the longitudinal axis
of the shaft such that the fibers of one inner unidirectional bias
layer are oriented at a substantially equal but opposite angle with
respect to the orientation of fibers belonging to the next inner
unidirectional bias layer.
8. The golf club shaft according to claim 2, wherein the outer
unidirectional bias layers are formed by a tape having
unidirectional reinforcement fibers and wound spirally along the
selected longitudinal portion of the shaft.
9. The golf club shaft according to claim 1 wherein the outer layer
extends at least half the length of the shaft from a tip end of the
shaft.
10. A method of producing a golf club shaft, comprising: providing
an elongated mandrel having an outside surface shaped to form the
inside surface of the shaft; applying about the entire length of
the mandrel at least one flexural rigidity layer of composite
material, reinforcing fibers of which are oriented substantially
parallel to the longitudinal axis of the mandrel; to form a tubular
body for the shaft; and applying concentrically about the at least
one flexural rigidity layer, at least one outer layer having no
longitudinally-oriented fibers, the at least one outer layer
disposed over at least one third the longitudinal length of the
shaft.
11. The method according to claim 10, further comprising: applying
about the entire length of the mandrel at least one bias layer of
composite material, unidirectional reinforcing fibers of which are
oriented at an angle with respect to the shaft's longitudinal axis,
the unidirectional reinforcement fibers successive bias layers
oriented at substantially equal but opposite angles with respect to
the orientation of fibers belonging to an adjacent bias layer,
wherein the at least one flexural rigidity layer is applied to the
mandrel first, forming an innermost one or more bias layers of the
shaft, the at least one flexural rigidity layer and at least one
outer layer respectively disposed about the mandrel.
12. The method according to claim 10, wherein the at least one
outer layer includes unidirectional reinforcement fibers oriented
at an angle with respect to the longitudinal direction of the
shaft, each adjacent outer layer having its reinforcement fibers
oriented at a substantially equal but opposite angle with respect
to reinforcement fibers of an adjacent outer layer.
13. The method according to claim 11 wherein the angle of the
unidirectional reinforcing fibers of the at least one bias layer is
between about +35.degree. and +55.degree. or between about
-35.degree. and -55.degree. with respect to the longitudinal axis
of the shaft.
14. The method according to claim 10 wherein at least one of the
outer layers is formed by spirally wrapping a tape comprising the
unidirectional fibers.
15. The method according to claim 11 wherein at least one of the
bias layers is formed by spirally wrapping a tape comprising the
unidirectional fibers of each bias layer.
16. The method according to claim 10 wherein the at least one outer
layer is disposed over at least half the longitudinal length of the
shaft.
Description
[0001] This Nonprovisional application claims priority under 35
U.S.C. .sctn.119(e) on U.S. Provisional Application No(s).
61/350,446 filed on Jun. 1, 2010, the entire contents of which are
hereby incorporated by reference.
FIELD OF INVENTION
[0002] This disclosure relates to golf club shafts, and more
particularly to unique disposition of fiber layers in composite
golf club shafts having elongated tubular bodies composed of
fiber-and-resin composite materials.
BACKGROUND OF THE INVENTION
[0003] Composite golf club shafts typically have hollow tubular
bodies that taper longitudinally from larger, so-called "butt" or
"grip" ends toward smaller, so-called "tip" ends upon which golf
club heads are mounted in the completed golf clubs. Such shafts
typically are generally circular in transverse cross-sectional
shape, both at the outside and inside surfaces of the shaft, having
walls that are of selected thicknesses and compositions to provide
the strength, flexibility and weight desired for a particular golf
club.
[0004] The design and manufacture of composite golf club shafts are
highly developed arts, providing a wide variety of different shafts
with characteristics that are intended to suit the abilities and
personal preferences of a wide variety of golfers. Typically,
composite shafts are designed to be concentric about their
longitudinal axis while varying substantially in outside diameter
from the larger grip end to the smaller tip end. The concentricity
of the inside and outside surfaces is designed to be very precise,
to produce the desired wall thickness and flexing characteristics,
and remains stable when at rest, that is, when not loaded and
stressed by outside forces.
[0005] During the swing, however, the forces acting on the shaft as
the club is swung through the golf stroke are great enough to
deform the shaft, longitudinally in flexing of the length of the
shaft and torsionally in twisting of the shaft, and also
transversely, causing the cross-sectional shape of the shaft to
deform and become oval or elongated. Thus deformation is resisted
by the wall strength of the shaft, referred to as "hoop strength",
but occurs in different degrees and directions, first in the
so-called "swing plane (or planes)" of the golfer's swing and
secondarily in the so-called "droop plane" that is generally
perpendicular to the swing plane. The amounts of these deformations
are functions of the forces applied throughout the swing and ball
impact, and the physical properties of the shaft resisting these
forces.
[0006] In the industry, various approaches are available to provide
the desired properties in the shaft for improved performance,
including increasing the wall thickness and the amounts of
different composite materials in the wall, and varying the angles
of the fibers in the composite materials relative to the
longitudinal axis of the shaft.
[0007] However, conventional composite golf shafts typically
include bias plies with fibers substantially oriented plus and
minus 45.degree. to the shaft axis to influence torsional
(twisting) flexibility, and longitudinal plies with fibers parallel
to the shaft axis to influence longitudinal (bending) flexibility.
The bias plies 30a, 30b illustrated in FIG. 7 are applied closest
to the center core of the golf shaft and the longitudinal fiber
plies 32a to 32d are applied concentrically about the inner bias
plies 30a, 30b last, and furthest from the core of the shaft.
Although the figure shows two bias plies and four longitudinal
plies, the number may vary. After curing, an amount of material is
removed from the outermost longitudinal ply 32d of the golf shaft
(e.g., by sanding) to obtain a desired shaft stiffness. A
significant portion of the longitudinal fibers are thus sanded
away. The conventional composite golf shaft loses approximately
5.75% of its stiffness during this material removal process.
SUMMARY OF THE DISCLOSURE
[0008] Consistent with one or more embodiments described in detail
herein, a golf club shaft includes an elongated, generally tapered
shaft having a generally circular transverse cross-sectional shape.
The circular wall of the shaft has at least one flexural rigidity
layer and at least one outer layer. The flexural rigidity layer(s)
are disposed around the entire length of the shaft, and
reinforcement fibers of the flexural rigidity layer(s) are
substantially oriented in the longitudinal direction of the shaft.
The outer layer(s) have no longitudinally-oriented fibers and are
disposed concentrically about the outermost flexural rigidity, and
extend at least one third the length of the shaft from a tip end of
the shaft.
[0009] Consistent with one or more method embodiments described in
detail herein, a golf club shaft is produced by steps including
providing an elongated mandrel, applying flexural rigidity layer(s)
and applying outer layers. The mandrel has an outside surface
shaped to form the inside surface of the shaft. The flexural
rigidity layer, of composite material, is applied about the entire
length of the mandrel and includes reinforcing fibers which are
oriented substantially parallel to the longitudinal axis of the
mandrel to form a tubular body for the shaft. The outer layer(s)
are applied concentrically about the flexural rigidity layer(s),
and at least one outer layer has no longitudinally-oriented fibers.
The at least one outer layer is disposed over at least one third
the longitudinal length of the shaft.
[0010] Further scope of applicability of the present invention will
become apparent from the detailed description given hereinafter.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art from
this detailed description.
BRIEF DESCRIPTION OF THE FIGURES
[0011] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
[0012] FIG. 1 is a plan view of a golf club shaft incorporating
features consistent with some embodiments of the present
disclosure;
[0013] FIG. 2 is a transverse cross-section view near the tip end
of a golf club shaft incorporating features consistent with some
embodiments of the present disclosure;
[0014] FIG. 3 is a transverse cross-section view near the butt end
of a golf club shaft incorporating features consistent with some
embodiments of the present disclosure;
[0015] FIG. 4 is a plan view illustrating unidirectional fiber
plies used in construction of a golf club consistent with some
embodiments of the present disclosure;
[0016] FIG. 5 is a plan view of unidirectional fiber plies used in
construction of a golf club consistent with other embodiments of
the present disclosure;
[0017] FIG. 6 is a plan view of unidirectional fiber plies used in
construction of a golf club consistent with other embodiments of
the present disclosure;
[0018] FIG. 7 is a plan view of materials used in conventional
construction of golf club.
[0019] FIG. 8 is a plan view of a mandrel used in construction of a
golf club consistent with embodiments of the present
disclosure.
DETAILED DESCRIPTION
[0020] The following detailed description refers to the
accompanying drawings. The same reference numbers in different
drawings identify the same or similar elements. Also, the following
detailed description does not limit the invention. Instead, the
scope of the invention is defined by the appended claims and
equivalents thereof.
[0021] As shown in the drawings for purposes of illustration, a
composite golf club according to at least some embodiments of the
invention is indicated generally by the reference number 10, having
an elongated tubular body 11 that has a butt or grip end 12, the
upper right hand end in FIG. 1, and a tip end 13. A club head (not
shown) will be mounted on the tip end, and a grip (not shown) will
be disposed around the butt end portion to complete the golf club
in the conventional fashion.
[0022] The body 11 of the golf club shaft 10 shown in FIG. 1 has a
longitudinal taper, as is typical in such shafts, from the larger
butt end 12 toward the smaller tip end 13, and has a conventional
cross-sectional shape that normally is circular or annular as shown
in FIG. 2 when at rest, having inside and outside surfaces 14 and
15 that are circular in transverse cross-section and are generally
concentric about the longitudinal axis of the shaft, indicated by
the line 17 in FIGS. 1-3. It is to be understood that shafts may be
designed and manufactured with variations in the wall thickness
along the length of the shaft, for purposes of variations in the
performance of the shaft in a golf club.
[0023] As discussed in general in the Background section, composite
golf club shafts are composed of fiber-and-resin materials that are
formed into the desired tubular shape on a tapered mandrel,
typically composed of metal and having an outside shape that is the
shape desired for the inside surface of the shaft to be produced,
usually longitudinally tapered and of circular cross-sectional
shape. The fiber-and-resin material is wrapped around the mandrel,
usually in sheet form that is cut into selected geometric shapes
and applied to form a plurality of layers of the sheet materials to
make up a body of selected wall thickness and length, which may be
in the range of thirty to sixty inches before being cut down to
final size. Various materials, with various fiber types and
orientations, are used according to the design of each shaft, in
accordance with principles and methods that are well known in the
industry. The term "composite material" is used in the broad sense
used in the industry, and the types of fibers in the composite
materials may be of a variety of types, including, but not limited
to, graphite, fiberglass, boron, various metallics and spectra,
according to the principles that are well known by those skilled in
the art.
[0024] Typically, the assembled shaft then is wrapped in a shrink
wrap film and cured in an oven (not shown) to form the hardened
hollow composite body of the golf club shaft. The mandrel then is
withdrawn from the assembly, leaving the shaft with its inside
surface matching the outside surface of the mandrel. Subsequently,
the shaft can be cut to a desired length for assembly into a golf
club. It is to be noted that other procedures, such as filament
winding of fiber-and-resin tape or roving onto a mandrel, may be
used for applying the composite material, wrapping of sheet
material being the illustrative manner of forming the shaft body
described herein.
[0025] According to at least one embodiment of the shaft shown in
FIGS. 2 and 3, transverse cross-sections of the shaft at areas near
the tip end and the butt end, respectively, reveal the different
layers constituting the shaft at the respective portions. One or
more sheets of bias material form inner bias layer 22. Each sheet
of bias material includes unidirectional reinforcing fibers
oriented at an angle selected between +35.degree. and +55.degree.
or -35.degree. and -55.degree. with respect to longitudinal axis
17. When two or more bias layers are applied as the inner-most
layer, each sheet includes unidirectional reinforcing fibers
oriented at a substantially equal but opposite angle with respect
to an adjacent bias layer. For example, if a first bias layer has
fibers oriented at +45.degree. with respect to the longitudinal
axis, fibers of a next bias layer are oriented at -45.degree. with
respect to the longitudinal axis.
[0026] A flexural rigidity layer 20 is, in the embodiment
illustrated in FIGS. 2 and 3, disposed on the inner bias layer 22.
Each of one or more sheets of composite material constituting the
flexural rigidity layer includes unidirectional fibers oriented
substantially parallel to the longitudinal axis 17.
[0027] FIG. 2 includes an outer material layer 24 which may include
one or more outer bias layers similar to the inner bias layers or a
coating of non-fibrous material. The outer material layer 24 is
disposed along at least one third the length of the shaft,
typically from the tip end to at least one third the length of the
shaft. It will be appreciated by those of skill in the art,
however, that the outer material layer may be disposed at other
locations, and may include lengths between one third and full
length of the shaft. As shown if FIG. 3, a length near the butt end
of the shaft may be devoid of outer material layer 24.
[0028] FIGS. 4-7 illustrate sheets of materials used in manufacture
of a golf club shaft according to the present disclosure. In the
Figures, the materials shown from top to bottom respectively
correspond to layers beginning at the inner surface 14 and
concluding with the outer surface 15. Although particular numbers
of sheets are illustrated, it will be appreciated by one having
ordinary skill in the art that the number of sheets may be varied
according to design. For example, the Figures show four sheets of
flexural rigidity material in each figure, whereas the number of
sheets may be as few as one or have many more.
[0029] FIG. 4 provides sheets of composite materials according to
one embodiment of the invention in which no inner bias layers are
included. Thus, the inner surface 14 of the golf club shaft 10 is
formed by flexural rigidity layer 20, comprising sheets 20a, 20b of
composite material having unidirectional fibers oriented
substantially in parallel with the longitudinal axis 17. Outer
surface 15 is formed by outer layer 24, comprising sheets 24a and
24b of composite material, each alternately having fibers
unidirectionally oriented at an angle between +35.degree. and
+55.degree. or at an equal but opposite angle between -35.degree.
and -55.degree.. Alternatively, outer layer 24 may instead comprise
a non-fiber coating as described above. In either case the outer
surface may be sanded or otherwise diminished without substantially
affecting the flexural rigidity layers. Because at most only a
portion of the flexural rigidity layer(s) is exposed, removal of
portion of the outer surface decreases flexural rigidity far less
than the approximately 5.75% decrease resulting from removal in the
conventional method. (In some disclosed embodiments, for example,
only 1.9% of flexural rigidity is lost during sanding.) Although
the FIG. 4 illustrates the outer layer having a length similar to
that of the flexural rigidity layers, it will be appreciated in
view of this disclosure that the outer layer 24 may be as short as
one third the length of the shaft.
[0030] FIG. 5 provides sheets of composite materials for forming
another embodiment of golf club shaft 10. In addition to the
flexural rigidity layer 20 and outer 24, this embodiment includes
inner bias layer 22 comprising bias material sheets 22a, 22b, each
alternately having fibers unidirectionally oriented at an angle
between +35.degree. and +55.degree. or at an equal but opposite
angle between -35.degree. and -55.degree.. In this embodiment, it
is clear that outer layer 24, including sheets 24a, 24b, has a
length n greater than or equal to one third the shaft length m.
[0031] FIG. 6 illustrates an embodiment similar to that of FIG. 5
except the outer layer 24, including sheets 24a, 24b has a length
equal to that of the flexural rigidity sheets 20a-d and inner bias
sheets 22a, 22b.
DESCRIPTION OF THE METHOD
[0032] The method of the invention includes steps of applying to a
mandrel 40, in a particular order, sheets of composite material
each having reinforcing fibers oriented in a single direction. The
applied sheets are cured, and the resulting tubular shaft is
removed from the mandrel 40. Portions of material of the outer-most
layer may be removed; for example, to achieve a particular target
weight, stiffness, and/or size targets.
[0033] The mandrel 40, illustrated in FIG. 8, is conventional in
its configuration. It has an elongated shape with an outside
surface 42 shaped to form the inside surface 14 of a shaft, herein
tapered and of circular cross section. A coupling 35 projects
outwardly from the mandrel's larger end, and may be variously
formed. The coupling 35 may have, for example, a hexagonal head on
a coaxial stem 46 joined to the shaft, for engagement by a tool
(not shown) for turning the mandrel as it is withdrawn endwise from
the shaft 10. In some embodiments consistent with this disclosure,
the first sheets of composite material applied to the mandrel have
fibers oriented in a direction substantially parallel to the
longitudinal axis of the mandrel, thus providing flexural rigidity
to the shaft. The number of sheets, type of reinforcing fibers, and
type(s) of composite material may be selected for their stiffness,
thickness, weight, etc.
[0034] Concentrically disposed upon at least a portion of the
flexural rigidity layers may be added one or more outer layers of
material. The outer layers are disposed over at least one third the
length of the shaft starting at the smaller, tip end of the shaft,
although it will be appreciated that the outer layers may be
disposed over portions of the shaft other than the tip end. In one
embodiment, the outer layers may include sheets of composite
material having unidirectional reinforcement fibers bias-oriented
at an angle with respect to the longitudinal axis of the mandrel.
The bias-orientation of reinforcement fibers contributes torsional
stiffness to the shaft portion upon which it is applied. In this
case, the unidirectional fibers of each subsequently applied sheet
of composite material are oriented at an equal, but opposite, angle
with respect to an adjacent outer layer sheet. For example, if the
first outer layer sheet has fibers oriented at +45.degree. with
respect to the longitudinal axis, the reinforcement fibers of the
next outer layer sheet thus may be oriented at -45.degree. with
respect to the longitudinal axis.
[0035] In another embodiment, the outer layer(s) may include one or
more coatings of varnish, paint, plastic, or the like. Whether
composite fiber sheets or coatings, the outer layers may be at
least partially removed by sanding or other means to adjust the
weight, size, stiffness, structural smoothness, or other
characteristics.
[0036] In another embodiment, at least one inner, bias layer is
applied to the mandrel prior to the addition of flexural rigidity
layers. Each inner bias layer includes unidirectional reinforcement
fibers oriented at an angle with respect to the mandrel's
longitudinal axis such that the unidirectional reinforcement fibers
of adjacent inner bias layers are oriented at more-or-less equal
but opposite angles. For example, if an inner bias layer is applied
to the mandrel such that the unidirectional reinforcement fibers of
one inner bias layer are oriented at +45.degree. with respect to
the longitudinal axis of the mandrel and shaft, an adjacent inner
bias layer is next applied such that its unidirectional
reinforcement fibers are oriented at about -45.degree. with respect
to the longitudinal axis of the mandrel and shaft.
[0037] In the case of either the inner bias layers or outer layers
that include reinforcing fibers, the complementary angles of fibers
for adjacent layers may be in the range of +35.degree. to
+55.degree. or -35.degree. to -55.degree.. That is, adjacent bias
layers (inner or outer), for example, may be substantially oriented
at +35.degree. and -35.degree.. It is to be appreciated that when a
multiplicity of bias layers are applied, the complementary angles
selected for the unidirectional fibers may all be the same equal,
but opposite angles, or pairs of layers may have varying equal but
opposite angles.
[0038] The terms "a" and "an" herein do not denote a limitation of
quantity, but rather denote the presence of at least one of the
referenced item. Unless defined otherwise, technical and scientific
terms used herein have the same meaning as is commonly understood
by one of skill in the art to which this disclosure belongs.
[0039] While the invention has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
disclosure without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiments disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the appended
claims.
* * * * *