Note: Descriptions are shown in the official language in which they were submitted.
LIGHTWEIG2IT STEEL GOLF SHAFT
Backqround Of The Invention
This invention relates to lightweight steel golf
shafts and, more particularly, to golf clubs having lightweight
steel shafts with a plurality of step~ arranged in ~ets along the
lengths of the ~haft~ and to their methods of fabrication.
E~ e~ Of The Backqround Alt
In the game of golf, a player holds a club at a
grip at the upper or butt end and 6wings it 80 that the head at
the lower or tip end hits a ball to propel it toward a hole. The
game of golf ha~ been played for hundreds of years and has
produced numerous technical advancements in the ball, the golf
course, and the club in an effort to lower scores and add to the
en~oyment of the game. One area of particular importance is the
golf club shaft, the part of the club between the grip and the
head.
A large number of shaft improvements relate to
materials. Shafts have been fabricated of materials ~uch as
wood, steel, glass, etc. as well a~ more complex and expensive
composite graphite materials. Advancements in materials allow
for proper strength, weight, flexibility, torque, etc.
Mechanical advancements have also been made to
promote proper shaft performance. Consider shaft BiZe, length,
diameter, thickness, taper, weight distribution and steps. Steps
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have been long utilized for ~tengthening shafts along their
lengths to compensate for material and weight reduction. Such
stepped shafts, however, generally employ a limited number of
steps spaced along the length for strengthening purposes. They
are ~ot, however, arranged in sets with pluralities of steps in
each set in the manner a~ set forth herein for controlling the
regions of torque abatement and flexibility enhancement.
While these prior art approaches discussed above,
as well as the prior art patent referred to in the Information
Di~closure Statement of this application, describe advantages in
golf club shaft constructions, none discloses the structure by
which applicant's invention may be utilized to optimize golf
~haft design and performance for lower scores and greater
en~oyment during a golf game.
As illustrated by a great number of prior patents
and known techniques, efforts are continuously being made in an
attempt to improve golf shafts and render their use more
efficient, convenient, reliable and economical. None of these
previous efforts, however, provides the benefits attendant with
the present invention. Additionally, prior techniques do n~ot
suggest the pre~ent inventive combination of component elements
as disclosed and claimed herein. The present invention achieves
its intended purposes, ob~ectives and advantages over the prior
art devices through a new, useful and unobvious golf shaft which
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is 6imple to u~e, with the utilization of a minimum number of
component parts, at a reasonable cost to manufacture, and by
employing only readily available materials.
Although many ~uch advances are noteworthy to one
extent or another, none achieves the ob~ectives of an efficient,
reliable, inexpensive, golf shaft designed to accommodate the
needs of a full range of clubs.
Therefore, it is an object of this invention to
pxovide an improved golf club comprising a head section with a
grip thereon, a tip section with a head thereon, and a shaft
therebetween, the shaft being formed of a plurality of ~ets of
6tep6 along its length with decreasing diameters from the head
6ection to the tip ~ection, the sets of steps being spaced from
each other and from the ends of the shaft.
It is another object of this invention to step golf
club shaft6 for creating 6tiff and flexible sections designed to
accommodate the intended movement of the golf club shaft during a
player'6 ~wing.
It is a further ob~ect of the invention to abate
torque in golf club shafts during a player's swing.
Lastly, it is an ob~ect of the present invention to
engineer golf club~ to produce the intended action and convert
the movement of a player' 8 hands, arms and body to the action of
t the golf club head during the hitting of the ball.
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The foregoing ha~ outlined some of the more
pertinent objects of the invention. These objects should be
construed to be merely illustrative of some of the more prominent
features and applications of the intended invention. Many other
beneficial results can be attained by applying the di~closed
invention in a different manner or by modifying the invention
within the scope of the disclosure. Accordingly, other ob~ects
and a fuller understanding of the invention may be had by
referring to the summary of the invention and the detailed
description of the preferred embodiment in addition to the scope
of the invention defined by the claims taken in conjunction with
the accompanying drawings.
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SUMMARY OF THE INVENTION
The invention i~ defined by the appended claims
with the specific embodiment shown in the attached drawings. For
the purpose of summarizing the invention, the invention may be
inco~porated into an improved golf club shaft formed of steel in
a generally cylindrical configuration with a tip end and a butt
end and a central aperture extending axially the entire length
thereof. A plurality of ~ets of steps are formed on the shaft
continuously decreasing in diameter externally and internally
from the butt end to the tip end. About 5-1/4 inche~ to about 8-
3/4 inches of the upper 6haft ad~acent to the butt end and about
9-1/2 inches to about 12 inches of the lower shaft ad~acent the
tip end are of a common exterior diameter. The shaft has three
spaced sets of steps and four un-stepped regions. The ~teps of
the central region are spaced greater than the steps ad~acent to
the ends of the shaft. The set of steps constitutes between
about 16-1/4 inches and 20 inches of the length of the shaft.
~he regions between the stepped sections constitute between about
6 inches of the length of the shaft. The shaft weighs between
about 3.81 and 4.00 ounces. The shaft has a thickness of about
0.016 inche~ to about 0.020 inches ad~acent to its ends and about
0.014 inchQs therebetween.
The invention may also be incorporated into an
improved steel golf shaft formed in a generally cylindrical
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configuration with a tip end and a butt end, the shaft having a
centrai aperture extendinq axially the entire length thereof,
three set~ of steps continuously decreasing in diameter
externally and internally from the butt end to the tip end, the
~teps of the central set being spaced from each other by a
distance greater than the distance between the steps of the other
sets.
La~tly, the invention may be incorporated into an
improved golf club comprising a head section with a grip thereon,
a tip section with a head thereon, and a shaft therebetween, the
6haft being formed of a plurality of sets of steps along its
length with decreasing diameters from the head section to the tip
section, the sets of steps being spaced from each other and from
the ends of the shaft.
The foregoing ha~ outlined rather broadly the more
pertinent and important features of the present invention in
order that the detailed description of the invention that follows
may be better understood 80 that the present contribution to the
art can be more fully appreciated. Additional features of the
invention will be described hereinafter which form the sub~ect of
the claim~ of the invention. It should be appreciated by those
skilled in the art that the conception and the disclosed specific
~mbodiment may be readily utilized as a basis for modifying or
designing other structures for carrying out ~he same purposes of
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the present invention. It should also be realized by those
skilled in the art that such equivalent constructions do not
depart from the 8pirit and ~cope of the invention as set forth in
the appended claims~
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BRIEF DESCRIPTION OF THE DRAWINGS
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For a fuller understanding of the nature and
ob~ects of the invention, reference should be had to the
following detailed description taken in con~unction with the
accompanying drawings in which:
Figure 1 is a perspective illustration of a golf
clu~ employing a shaft constructed in accordance with a primary
embodiment of the present invention.
Figure 2 is a plan view of the shaft shown in
Figure 1.
Figures 3, 4, and 5 are plan views similar to
Figure 2 buS showing alternate shaft constructions.
Figure 6 is an enlarged sectional view taken along
line 6-6 of Figure 2.
Figures 7 and 8 are graphs of the results of tests
performed with irons, comparing shafts of the present invention
(Figure 7) with those of conventional shafts (Figure 8).
Figures 9 and 10 are graphs of the results of tests
similar to Figures 7 and 8 but of tests performed with woods,
comparing the shaft of the present invention (Figure 9) with
those of conventional woods (Figure 10).
Similar referenced character~ refer to similar
parts throughout ~he several Figures.
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DETAILED DESCRIPTION OF THE INV~NTION
Shown in Figure 1 is a golf club 10 having a grip
12 and head 14 coupled by a shaft 16 constructed in accordance
with the principles of the present invention. The shaft of
Figures 1 and 2 i6 for an iron club of regular flexibility. The
upper or butt section 18 is 5-1/4 inches in length and 0.625
inches in exterior diameter. This second section or upper
stepped section 20 is 3-1/2 inches in length with steps 22 of 1/2
inch whereby the shaft decreases to 0.620, 0.615, 0.610, 0.605,
0.600, 0.595 and 0.590 inches in exterior diameters. The upper
interior un-stepped section 24 is 2-1/2 inches in length and has
an exterior diameter of 0.580 ~nches. The central stepped
section 26 is 11-1/4 inches in length with a plurality of widely
spaced 6teps 28 of 1-1/4 inch at 0.565, 0.550, 0.535, 0.515,
0.495, 0.475, 0.460, 0.445 and 0.430 inches in exterior diameter.
The next section is the lower interior un-stepped section 30
which i8 of a length of 3-1/2 inches at an exterior diameter of
0.415 inches. Next comes the lower stepped section 32 which is
1-1/2 inches in length. The diameters of the steps 34 are 0.400,
0.390 and 0.380 inches, closely 6paced steps as in the upper
stepped section 20. For aesthetic purposes this lower stepped
~ection is provided with silk screen rings 38 at its extremitie~.
~astly, the lower~or stepped section is 11-1/2 inches in length
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with a common exterior diameter of 0.370 inches ending in a lower
or tip 6ection 42 for coupling with head 44.
The shaft 16 iB fabricated of steel in a generally
cylindrical configuration with a central aperture extending
axially through the entire lenqth thereof. The shaft is
lightweight, about 3.87 ounces, plus or minus 1/8 ounce. The
wall has a thickness of about 0.016 inches at the butt section 16
and 0.020 inches ad~acent to the tip ~ection 42 for greater
rigidity but a thickness of about 0.014 inches therebetween for
reduced weight.
The ~haft is formed with three sets of steps at
sections 20, 26 and 32, continuously decreasing in diameter
externally and internally from the butt section 18 to the tip
section 42. At least about 5-1/4 inches of the shaft ad~acent
the butt end and about 11-1/2 inches of the shaft ad~acent the
tip end are not stepped and are of a common diameter internally
and externally~ The stepped sections con6titute about 16-1/4
inches of the length of the shaft whereas the un-stepped sections
between the stepped sections constitute about 6 inche~ of the
shaft.
The Figure 3 shaft is also a shaft for an iron
club. It is of an identical construction to the Figure 2 shaft
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except that the tip section is 2 inches shorter and the butt
section i~ 2 inches longer. The weight i~ 4.00 ounces plu8 or
minus 1/8 ounce. This effectively creates a stiffer shaft.
Shown in Figure 4 i8 a shaft 46 also consSructed in
accordance with the principles of the present invention. The
shaft of Figure 4 i~ for a wood club of regular flexibility. The
upper or butt section 48 i8 7 inches in length and 0.625 inches
in exterior diameter. This second section or upper stepped
section 50 i8 3-1/2 inches in length with steps 52 whereby the
shaft decreases to 0.620, 0.515, 0.610, 0.605, 0.600, 0.595,
0.590 and 0.585 inches in exterior diameters. The upper interior
un-stepped section 54 is 2-1/2 inches in length and has the
exterior diameter of 0.580 inches. The central stepped section
56 i8 15 inches in length with a plurality of widely spaced steps
58 at 0.565, 0.550, 0.535, 0.520, 0.505, 0.490, 0.475, 0,460,
0.4~5, 0.430, 0.415 and 0.400 inches in exterior diameter. The
next section is the lower interior un-stepped section 60 which i~
of a length of 3-1/2 inches at an exterior diameter of 0.385
inches. Next comes the lower stepped fiection 62 which is l-l/2
inches in length. The diameters of the steps 64 are 0.370,
0.355, and 0.345 inqhes, closely spaced steps as $n the upper
stepped section 50. For aesthetic purposes this lower stepped
BeCtion i8 provided with silk screen rings 38 at its extremities.
~astly, the lower or stepped section is 12 inches in length with
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a common exterior diameter of 0.335 inches ending in a lower or
tip section 72.
The shaft 46 i5 also fabricated of steel in a
generally cylindrical configuration with a centsal aperture
extending axially through the entire length thereof. The shaft
is lightweight, about 3.87 ounces, plus or minus 1/8 ounce. The
wall has a thickness of abaut 0.016 inches at the butt section 76
and and a thickness of about 0.020 inches ad~acent to the tip
section 42 for greater rigidity but a thickness of about 0.014
inches therebetween for reduced weight.
The shaft 46 is formed with three sets of steps at
6ection 50, 56 and 62, continuously decreasing in diameter
externally and internally from the butt section 48 to the tip
~ection 72. At least about 7 inches of the 6haft ad~acent to the
butt end and about 12 inches of the 6haft adjacent the tip end
are not stepped and are of a common diameter internally and
externally. The stepped sections constitute about 20 inches of
the length of the shaft whereas the un-stepped sections between
the stepped sections constitute about 55-1/2 percent of the
shaft.
The Figure 5 shaft 46 is also a shaft for a wood
club. It is of an identical construction to the Figure 4 shaft
except that the tip section is 1-3/4 inches shorter while the
butt section iB 1-3~4 inches longer. The weight i6 4.00 ounce~
plus or minu~ 1/8 ounce. Thi~ effectively creates a ~tiffer
shaft.
Greater detail of the 6haft can be seen with
reference to the cross-~ectional illustration in Figure 6. Each
6tep~reduces the diameter of the shaft interiorly and exteriorly
in the direction from the butt end to the tip end. At each step,
the shaft is formed with curves forming a smooth radius during
the conventional fabrication technique.
Golf clubs provided with shafts in accordance with
the present invention are lightweight steel golf shafts with a
slightly larger and stiffer butt than standard to remove the flex
from the butt area of the shaft and to create more kick lower in
the shaft for ea~e in launching the ball. The shaft tip is not
designed with a small weak tip that would create unwanted
whipiness. In fabricating a matched set of clubs, the shafts as
described above are cut or trimmed from the tip end to an
appropriate amount to couple with appropriate heads 14 for
creating ma~ched sets of clubs. The progressively trimmed shaft
tips create a matched set of golf shafts which 8110w the long
irons to have more kick than conventionally designed steel~
shafts, the mid irons somewhat more kick than conventionally
designed steel shafts, and the short irons an average amount of
kick when compared to conventional steel shafts.
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The same tip trLmming concept i8 used to also
fabricate a matched set of shafts for golf woods. The longest
wood has the most kick, the next longest has the next most kick,
etc. while the shortest wood is more conventional in its kick.
U~ing golf clubs with exactly the ~ame loft, lie,
length, and swing weight on the irons and the exact same loft,
lie, face angle, roll, bulge length, and swing weight on the
woods, a test was conducted with a robotic golfer to determine
any difference in performance comparing the shaft of the present
invention against a control of the most popular weight steel
shaft.
The same power source, swing speed, set up and
6tandard test balls were used. A serie~ of face scanning hits
were performed in a center hit, toe hit, center hit, heel hit,
etc. sequence to show the scatter of shots that would occur from
these different types of hits that would simulate the tendencies
of live golfers.
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The test re~ults are as follows:
Gontrol Club with
Standard Steel Shaft Avg. Lateral Deviation
#5 Iron Distance from Center Line (Yds.)
Center Hit 166 .5 left
Toe Hit 162 .8 right
Heel Hit 161 3.6 left
Present Invention
#5 Iron
Center Hit 169 .1 right
Toe Hit 165 1.3 right
Heel Hit 164 .45 left
Control Club with Standard
Steel Shaft #l Wood
Center Hit 250 1.4 right
Toe Hit 236 18.6 right
Heel Hit 250 7.7 left
Present Invention
~1 Wood
Center Hit 256 1.5 left
Toe Hit 247 6.3 right
Heel Hit 253 3.8 left
As we can see from the distance results, the #5
iron of the present invention outdistanced the control #5 iron by
3 yards on each impact point on the club face. The "spread,~
average farthest shot left added to the average farthest shot
right, is shown to be 4.4 yards for the control club versus'a
much tighter or more accurate shot by 1.75 yards for the #5 lron
of the present invention. The wood club results show greater
di~tance produced ~ the shafted club of the present invention by
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3 to 11 yards, depending on the impart point on the club face.
The ~spread~ for the control club is 26.3 yards ver~us a very
much tighter 10.1 yards with the shafted wood of the pre~ent
invention.
Computer generated elipses are attached to show the
landing locations of the golf balls hit by each club. ~H", "T",
and "C" indicate the landing areas of the balls hit on the heel,
toe and center of the head, respectively. The larger the elipses,
the less accurate the club hits were. The larger the spread of
sll the elipses together, the less accurate the club hits were.
The data and the elipses both clearly 6how that the shafted clubs
of the present invention were longer and more accurate in
producing their hits.
The shaft is lightweight to create easier swings
and increased club head speed. The club's overall weight is
nearly as light as a club with a high modulus graphite shaft due
to a ~oint usage of the present inventive lightweight shaft and a
lighter than conventional weight grip. Even with the lighter
overall weight, conventional swing weight~ are achieved.
The butt of a shaft of the present invention is
firmer than conventional shafts to remove any unnecessary flex in
the hands area, thus creating a slightly lower flex point without
the need for a whippy flexible tip design.
The long iron shafts are designed to have the most
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amount of kick to aid in achieving proper ball tra~ectory, while
the mid-irons exhibit some increased kirk and the short irons,
the scoring clubs, yield firmer more conventional feel.
The shaft of the pre~ent invention has been proven
to be slightly longer in carry than conventional shafts but its
greater attribute i8 its extreme accuracy versus standard steel
and even the expensive high modulus graphite shafts. ~he landing
area from balls hit with shafts of the pre~ent invention are half
that of other conventional shafts.
The herein described lightweight steel golf shafts
may be used in any golf clubs. Superior results are realized
during use. Particularly superior results are realized when the
herein described shafts are used with golf clubs having the grip
as set forth in my co-pending U. S. Patent Application Serial
Number (Attorney Docket Number P-2907) filed
concurrently herewith.
The present disclosure includes that contained in
the appended claims as well as that of the foregoing description.
Although this invention has been described in its preferred forms
with a certain degree of particularity, it is understood that the
present disclosure of the preferred form has been made only by
way of example and numerous changes in the details of
construction and c,ombination and arrangement of parts may be
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re~orted to without departing from the spirit and scope of the
invention.
Now that the invention has been described,
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