Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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IMPROVED GOLF CLUB SHAFT WITH MULTIPLE KICK POINTS
Background
Field of the invention
This invention is directed to golf club shafts, in
general, and to golf club shafts made of carbon fiber
composite materials which are assembled with a unique
configuration, in particular.
Prior art
In recent years, the equipment used for the game of golf
has evolved dramatically. For example, so-called "wood" clubs
now include clubs referred to as "metal woods". The shafts in
the clubs have evolved from hickory to rolled steel to
aluminum to graphite to exotic materials such as titanium.
Shafts are also made of carbon fiber type materials.
All of the shafts have been designed to provide
substantial strength so that the shaft does not break. In
addition, the shafts are designed to provide various amounts
of flexure and/or stiffness. The golf club shafts have been
designed to provide varying types of energy storage and
release during the back swing and the forward swing in order
to impart greater amounts of energy at the striking of a golf
ball.
Wherever possible, manufacturers are continuing to
experiment and develop new golf club shafts by introducing new
types of materials and new types of assembly. The ultimate
golf club shaft is always pursued.
Summary of the Invention
This invention is directed to a golf club shaft made of a
composite material such as carbon prepreg or the like. The
shaft incorporates three cylindrical (or parallel) sections
integrally joined together by a pair of tapered sections. By
utilizing appropriate materials, the shaft can attain a
suitable amount of flexure and strength.
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The shaft is assembled by a unique method of providing
the composite materials, assembling the composite materials
and finishing the shaft.
Brief Description of the Drawinqs
Figure 1 is a schematic representation of a preferred
embodiment of the golf club shaft made in accordance with the
instant invention.
Figure 2 is a representation of the component pieces
which are assembled to form the golf club shaft of the instant
invention.
Figure 3 is a plan view of a partial assembly of the golf
club shaft of the instant invention.
Figure 4 is a plan view of another partial assembly of
the golf club shaft of the instant invention.
Figure 5 is a block diagram flow chart of the process by
which the golf club shafts of the instant invention are
assembled.
Description of a Preferred Embodiment
Referring now to Figure 1, there is shown a perspective
view of a golf club shaft made in accordance of the instant
invention. In this Figure, the golf club shaft 100 comprises
three parallel chambers 101, 102 and 103. These chambers or
sections are denoted as a parallel in that they are, in
effect, right cylinders.
The parallel sections 101 and 102 are joined by a tapered
section 104. Similarly, parallel sections 102 and 103 are
joined together by tapered section 105. As shown in Figure 1,
the tapered sections 104 and 105 are quite exaggerated.
The same general construction is equally applicable to
golf club shafts for so-called wood clubs and for iron clubs.
The most significant difference in the structure of the wood
or iron club shafts is the overall length dimensions. For
example, the shaft used with a wood club is typically on the
order of 45 inches in length while the shaft for an iron club
is on the order of 39 inches in length. The diameters of the
shafts at the butt end are approximately 0.60 inches (wood)
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and 0.615 inches (iron) while the diameters at the tip end are
approximately 0.335 inches (wood) and 0.370 inches (iron).
Referring now to TABLE 1, there is shown a listing of the
approximate dimensions (in millimeters) for the respective
sections of the wood club shafts and the iron club shafts.
TABLE 1 (mm)
SECTION
CLUB 101 104102 105 103 TOTAL
Length200 110 330 400 1001140
WOOD
Diam.15.2415.24-11.5 11.511.5-8.5 8.5
Length200 100 250 340 100990
IRON
Diam.15.6215.62-13.3 13.313.3-9.4 9.4
Referring now to Figure 2, there is shown a plurality of
components which are planar sheets of the appropriate carbon
fiber material. As noted, one of the suitable types of
material for a preferred embodiment of the invention is
referred to as a 5218 prepreg systems which is manufactured by
Cytec Structural Materials, Inc. of Anaheim, California. This
material is obtained in rolls or sheets which can be cut into
preferred configurations such as are shown in Figure 2.
The prepreg material includes carbon fibers and resins
which are arranged in a particular orientation. By
appropriately cutting the sheet, pieces of material having
different carbon fiber orientations can be provided.
For example, as shown in Figure 2, the pieces 210 and 220
are planar cuts of the prepreg material. The pieces 210 and
220 are, in essence, mirror images of one another. These
pieces are cut upon different biases in the prepreg material.
For example, piece 210 is cut on a +45 line while piece 220
is cut on a -45 line. Thus, pieces 210 and 220 are comprised
of elements which are disposed at a 90 relative bias overall.
In this embodiment, the pieces 210 and 220, referred to
as the bias layers, have butt ends and tip ends which are
identical in dimensions.
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In addition, each of the pieces 210 and 220 is cut to
eliminate certain triangular portions 211 and 212 thereof
which are designed to assist in developing the parallel
sections 101, 102 and 103 and the tapered sections 104 and 105
shown in Figure 1.
The other elongated components 250 and 260 have the same
length as the pieces 210 and 220, in this case approximately
1010 mm. The tip end of piece 250 is slightly wider than the
tip end of pieces 210 and 220. The tip end of piece 260 is
slightly wider than the tip end of piece 250. The butt end of
piece 260 is slightly wider than the width of the butt end of
piece 250 which is slightly wider than the butt end of pieces
210 and 220.
The pieces 250 and 260 are referred to as layers 1 and 2
and are both cut with a 0 bias in the prepreg material. That
is, in each piece the carbon fiber orientation is parallel to
the long axis of the piece.
The reinforcing layers 230 and 240 are also cut with a 0
bias. The reinforcing layer 230 is, of course, a right
triangular piece while the reinforcing piece 240 is right
trapezoidal in configuration.
It should also be noted that the prepreg material,
typically, has a thickness of approximately 0.15 mm. In
addition, this material can be formed to have different
tensile strength or tensile modulus. Typically, the pieces
210 and 220 are formed of the so-called 30 ton or high modulus
carbon fiber (as defined by the manufacturer) which includes
31~ resin content. Conversely, the layers 1 and 2 are
fabricated of an intermediate modulus carbon fiber material
with 34~ resin. The reinforcing layers are fabricated of
intermediate modulus carbon fiber material with 36~ resin.
The specific dimensions and modulus for the pieces as
shown and described, is not absolute. Modifications thereto
can be incorporated into the invention. The modifications
merely address the flexure and/or the strength of the shaft.
Referring now to Figure 3, there is shown a preliminary
step in the assembly of the shaft. In particular, the
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reinforcing layer 240 is laid up or affixed to the surface of
the piece 220. In the preferred arrangement, the right angle
corner of the right trapezoidal reinforcing layer 240 is
placed in the right angle corner of the tip end of bias layer
220. Typically, these layers are merely laid against each
other. That is, the layers tend to adhere to each other
sufficiently due to the tackiness of the material so that the
layers can be worked on subsequently.
Referring now to Figure 4, there is shown another step in
the preparation of the shaft. In this case, the bias layer
220 with the reinforcing layer 240 thereon is covered by the
bias layer 210 and the triangular reinforcing layer 230. In
particular, the bias layer 210 is aligned at the end thereof
with the reinforcing layer 240. However, the lower straight
edge of bias layer 210 is displaced from, but aligned in
parallel with, the lower straight edge of the reinforcing
layer 240. The offset between the two bias layers is,
generally, equal to the diameter of the mandril 401 on which a
rolling operation will take place.
After the bias layer 210 has been placed on top of the
bias layer 220 with the reinforcing layer 240 in place, the
triangular reinforcing piece 230 is placed on top thereof.
The right angle corner of the triangular reinforcing layer 230
is aligned with the right angle produced by the tip end of
bias layers 210 and 220 and the bottom edge of the bias layer
210 which is disposed on top of bias layer 220.
Referring now to Figure 5, there is shown a schematic
diagram or functional flow chart of the manufacturing process
for producing the improved golf club shafts of the invention.
In the flow chart, the stage or phase is defined as the
time when the individual pieces of composite material are
operated upon. Thus, the pieces that are cut during step 501
are the layers 210, 220, 230, 240, 250 and 260 which are shown
in Figure 2. In step 502, the layers are then assembled as
shown in Figures 3 and 4 and placed on the mandril 401. In
step 503, the assembled layers, together with the mandril 401,
are then placed in a conventional rolling machine which is
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adapted to roll the layers of prepreg material around the
mandril 401. The mandril is slightly tapered in accordance
with the desires of the shaft manufacturer.
In this case, the reinforcing layer 240 is rolled into
the tip end of the shaft as is the triangular reinforcing
layer 230. These components add strength and rigidity to the
shaft at the tip end and, together with the cut outs shown in
pieces 210 and 220, establish the parallel portions 101, 102
and 103 of the shaft 100 (see Figure 1).
In step 504, a second rolling operation is performed in a
conventional rolling machine. In this step, the first 0
layer comprising layer 250 is rolled around the mandril and
the rolled up layers 210, 220, 230 and 240 as occurred during
the first rolling operation.
In step 505, a third rolling operation is conducted
wherein layer 260 is rolled around the apparatus which was
produced during the second rolling operation in step 504.
In step 506, the unit, as produced by the third roll, is
wrapped in a suitable wrapper such as, but not limited to,
cellophane. This wrapper is fairly securely and snugly
wrapped around the assembly produced in step 505. This wrap
layer retains the other prepreg layers in a desired
configuration.
In step 507, the apparatus is heat treated. In
particular, the entire apparatus is placed in an oven where it
is heated to 250F for approximately two hours. Thus, the
wrap layer retains the shape of the apparatus. After the heat
treating is completed and the assembly has cooled to room
temperature, the wrap that was applied in step 506 is removed
in step 508.
The shaft is then run through a grinding operation in
step 509 wherein the surface of the assembly is rendered quite
smooth.
In step 510, the outer surface of the assembly is painted
in a conventional fashion. Many appropriate paint applicators
are known in the art. The type of paint used is also
conventional.
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In step 511, the assembly is run through a fine grind
procedure in order to smooth any imperfections which may have
been produced during the painting step.
In step 512, the assembly is submitted to a suitable
process for applying logos, or other indicia to the surface of
the assembly. Typically, this process can be done with a silk
screening operation.
In step 513, the completed assembly is given a clear coat
of lacquer, paint or the like to provide the ultimate finish
which can be either glossy or matt, as desired.
The shaft is now fully completed and ready to be
assembled to grips and heads to complete the manufacture of a
golf club. The shafts are not limited to the particular
configuration of wood or iron, except as noted above with
regard to the dimensions thereof.
While the process shown is Figure 5 is typical, it is
understood that modifications thereto can be made without
departing from the sphere of this invention. For example, the
third rolling step, i.e. step 505, can be omitted in some
cases, in particular, in the manufacture of shafts for iron
clubs.
Likewise, in step 506, material other than cellophane can
be used to wrap the shafts in some instances.
The temperature and time profile recited in regard to
step 507 can be altered, as desired, or as a function of the
material used to form the shaft.
It is possible, in some instances, to combine steps 508
and 509 wherein the grinding operation could remove the
wrapper.
While it is unlikely, the painting step 510 could be
omitted to leave the shaft in a natural state.
The finalizing steps of fine grindin~ (step 511),
applying a logo or similar indicia (step 512) and applying
clear coat (step 513) can be omitted or modified.
As described above, when the process shown in Figure 5 is
completed, the shaft 100 shown in Figure 1 is produced. This
shaft has a high standard of strength modulus, has flexibility
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suitable for most golfers and has two energy kick points such
as shown in Figure 1 wherein the energy stored in the shaft
during the backswing is released during the downswing by the
golfer.
Thus, there is shown and described a unique design and
concept of a golf club shaft and the method of making same.
While this description is directed to a particular embodiment,
it is understood that those skilled in the art may conceive
modifications and/or variations to the specific embodiments
shown and described herein. Any such modifications or
variations which fall within the purview of this description
are intended to be included therein as well. It is understood
that the description herein is intended to be illustrative
only and is not intended to be limitative. Rather, the scope
of the invention described herein is limited only by the
claims appended hereto.
