U.S. patent application number 14/632947 was filed with the patent office on 2016-09-01 for counterbalanced wedges.
This patent application is currently assigned to Taylor Made Golf Company, Inc.. The applicant listed for this patent is Taylor Made Golf Company, Inc.. Invention is credited to Sean Patrick Griffin, Derek Luther.
Application Number | 20160250532 14/632947 |
Document ID | / |
Family ID | 56798062 |
Filed Date | 2016-09-01 |
United States Patent
Application |
20160250532 |
Kind Code |
A1 |
Griffin; Sean Patrick ; et
al. |
September 1, 2016 |
COUNTERBALANCED WEDGES
Abstract
Described are embodiments of wedge-type golf clubs that include
a counterbalance weight located at the butt end of the shaft. The
shaft and/or grip of disclosed clubs can have reduced mass while
the club head and the butt of the shaft can have increased mass
compared to conventional clubs, which provides a similar overall
total mass but with an increase in the moment of inertia (MOI). The
increase in MOI compared to a conventional club of similar style
and mass can provide increased swing stability during a stroke,
decreasing unintentional waggling about the hand grip fulcrum. The
added weight in the head and the added weight in the butt of the
shaft can counterbalance each other so that the overall swingweight
of the club can be about the same as for a conventional,
non-counterbalanced club having the same total mass, thereby
providing a familiar feel and easy playability.
Inventors: |
Griffin; Sean Patrick;
(Encinitas, CA) ; Luther; Derek; (Manhattan Beach,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Taylor Made Golf Company, Inc. |
Carlsbad |
CA |
US |
|
|
Assignee: |
Taylor Made Golf Company,
Inc.
Carlsbad
CA
|
Family ID: |
56798062 |
Appl. No.: |
14/632947 |
Filed: |
February 26, 2015 |
Current U.S.
Class: |
473/292 |
Current CPC
Class: |
A63B 2053/0479 20130101;
A63B 2209/00 20130101; A63B 53/00 20130101; A63B 53/047 20130101;
A63B 60/24 20151001; A63B 53/10 20130101 |
International
Class: |
A63B 53/14 20060101
A63B053/14; A63B 53/04 20060101 A63B053/04; A63B 53/10 20060101
A63B053/10 |
Claims
1. A wedge-type golf club comprising: a club head having a static
loft angle greater than 45.degree.; a shaft having an upper end and
a lower end that is coupled to the club head; a hand grip coupled
to the shaft between the upper end and the lower end; and a
counterbalance weight coupled to the upper end of the shaft, the
counterbalance weight having a mass of at least 40 grams; wherein
the golf club has a total mass of at least 500 grams, a total
length of from about 35 inches to about 38 inches, an MOI.sub.CG of
at least 600 kg*cm.sup.2, and an inertial efficiency of at least
13.5%, wherein inertial efficiency is a unitless ratio of the
MOI.sub.CG per unit length squared divided by the total club
mass.
2. The golf club of claim 1, wherein the golf club has an inertial
efficiency of at least 14.8%.
3-5. (canceled)
6. The golf club of claim 1, wherein the counterbalance weight has
a mass of at least 50 grams.
7. The golf club of claim 1, wherein the golf club has a
swingweight that is between 2.6 N*m and 2.8 N*m.
8. The golf club of claim 1, wherein the counterbalance weight is
removably coupled to the upper end of the shaft, or is positionally
adjustable relative to the shaft.
9. (canceled)
10. The golf club of claim 1, wherein the hand grip has an outer
gripping surface and the counterbalance weight has an outer
surface, and the counterbalance weight is positioned above the hand
grip such that the outer surface of the counterbalance weight is
substantially contiguous with the outer gripping surface of the
hand grip.
11. The golf club of claim 1, wherein the shaft comprises a
bi-matrix shaft that comprises graphite material in an upper
portion of the shaft and steel in a lower portion or tip portion of
the shaft.
12. A wedge-type golf club comprising: a club head having a static
loft angle greater than 45.degree.; a shaft having an upper end and
a lower end that is coupled to the club head; a hand grip coupled
to the shaft between the upper end and the lower end; and a
counterbalance weight coupled to the upper end of the shaft
separate from the grip; wherein the counterbalance weight has a
mass of at least 40 grams; and wherein the golf club has a total
mass of at least 500 grams, a total length of from about 35 inches
to about 38 inches, an MOI.sub.CG of at least 600 kg*cm.sup.2, and
a swingweight that is in a range from about 2.5 N*m to about 3.0
N*m.
13. The golf club of claim 12, wherein the couterbalanance weight
has a mass of at least 50 grams.
14. The golf club of claim 12, wherein the golf club has a
swingweight that is in a range from about 2.6 N*m to about 2.8
N*m.
15. (canceled)
16. The golf club of claim 12, wherein the golf club's total mass
is between 500 grams and 600 grams.
17. The golf club of claim 12, wherein the counterbalance weight is
removably coupled to the upper end of the shaft, or is positionally
adjustable relative to the shaft.
18. The golf club of claim 12, wherein the club head has a total
mass of between 300 grams and 320 grams.
19. The golf club of claim 12, wherein the hand grip has a radial
outer gripping surface and the counterbalance weight has a radial
outer surface, and the counterbalance weight is positioned above
the hand grip such that the radial outer surface of the
counterbalance weight is substantially contiguous with the radial
outer gripping surface of the hand grip.
20. The golf club of claim 12, wherein the shaft comprises a
bi-matrix shaft that comprises graphite material in an upper
portion of the shaft and steel in a lower portion or tip portion of
the shaft.
21. The golf club of claim 1, wherein the club head has a total
mass of between 300 grams and 320 grams.
22. The golf club of claim 21, wherein the hand grip and the shaft
have a combined mass of 150 grams or less.
23. The golf club of claim 18, wherein the hand grip and the shaft
have a combined mass of 150 grams or less.
24. A wedge-type golf club comprising: a wedge-type club head
having a static loft angle greater than 45.degree.; a shaft having
an upper end portion and having a lower end portion that is coupled
to the club head; a hand grip coupled to the upper end portion of
the shaft, the hand grip having a lower hand grip portion
positioned around the shaft and an upper hand grip portion that is
positioned around the upper end portion of the shaft, wherein the
upper hand grip portion has an outer diameter that is smaller than
an outer diameter of the lower hand grip portion; and a
counterbalance weight positioned around the upper hand grip portion
of the hand grip and positioned above the lower hand grip portion,
the counterbalance weight having a greater density than the hand
grip and the shaft; wherein the lower hand grip portion has a
radial outer gripping surface and the counterbalance weight has a
radial outer surface, and the counterbalance weight is positioned
above the radial outer gripping surface such that the radial outer
surface of the counterbalance weight is substantially contiguous
with the radial outer gripping surface of the lower hand grip
portion.
25. The wedge-type golf club of claim 24, wherein the
counterbalance weight increases in diameter from a lower end of the
counterbalance weight to an upper end of the counterbalance
weight.
26. The wedge-type golf club of claim 24, wherein the upper hand
grip portion extends at least partially over the upper end of the
shaft, and the counterbalance weight extends at least partially
over an upper end of the upper hand grip portion.
Description
FIELD
[0001] This application relates to golf clubs, and more
particularly to wedges.
BACKGROUND
[0002] Golf is a game in which a player, choosing from a variety of
different golf clubs, seeks to hit a ball into each hole on the
golf course in the fewest possible strokes. A wedge is one type of
golf club, and is designed for hitting short, precise shots onto a
green, hitting high-lofted shots, and for hitting shots from
difficult lies, such as from tall grass or from a sand bunker. In
some wedge shots, the head of a wedge may travel through turf,
sand, or other materials prior to striking the ball. When swinging
a wedge, it is desirable to maintain a smooth, stable stroke to
provide optimal accuracy and precision.
SUMMARY
[0003] Described below are embodiments of wedges and other
iron-type golf clubs that are counterbalanced with significant mass
located near the butt of the shaft above the grip location.
Additional mass may also be added to the club head compared to a
conventional club head. In the disclosed golf clubs, the club head
and the butt end of the club can have increased mass compared to an
analogous conventional club, which provides an increase in overall
total mass, an increase in the moment of inertia about the CG of
the club (MOI.sub.CG), while maintaining a balance about the hand
grip fulcrum location that provides a similar swingweight compared
to a conventional club. The increase in club head mass and
MOI.sub.CG compared to a conventional club of similar style can
provide increased swing stability during a stroke, decreasing
unintentional waggling about the hand grip fulcrum, and thus
providing increased accuracy and precision to wedge shots. The
increase in club head mass and MOI.sub.CG can also help the club
head travel through soil, grass, sand, etc., with more momentum and
less interruption, providing more consistent and accurate ball
striking. The familiar swingweight of the disclosed clubs compared
to conventional clubs makes the disclosed club feel familiar to a
golfer and therefore the disclosed clubs can be readily playable in
place of a conventional club without the golfer having to
significantly change his swing.
[0004] The foregoing and other objects, features, and advantages of
the disclosed technology will become more apparent from the
following detailed description, which proceeds with reference to
the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 shows a conventional wedge-type golf club.
[0006] FIG. 2 shows an exemplary wedge-type golf club having a
counterbalance weight positioned at the butt end of the club.
[0007] FIG. 3 is a cross-sectional view of a butt end of an
exemplary club having a counterbalance weight positioned at the top
end of a hand grip and having a radial outer surface that is
substantially contiguous with a radial outer gripping surface of
the hand grip.
[0008] FIG. 4 is a cross-sectional view of a butt end of another
exemplary club having a counterbalance weight positioned within the
top end of the hand grip and secured to the top end of the
shaft.
[0009] FIG. 5 shows a wedge-type golf club at a point in a swing
just prior to striking a ball or contacting the ground behind the
ball.
[0010] FIG. 6 shows the wedge-type golf club at a point in the
swing after travelling through the ground behind the ball and just
after striking a ball.
[0011] FIG. 7 is a graph that illustrates displacement in the
ground direction as a function of time for two different wedge-type
golf clubs from the time they club head contacts the ground to a
time after the club head lifts above the ground.
DETAILED DESCRIPTION
[0012] Disclosed herein are embodiments of wedges and other golf
iron-type clubs that are counterbalanced with a counterbalance
weight located at or near the upper end or "butt end" of the shaft
above the gripping location. As used herein, the terms "wedge" and
"wedge-type golf club" mean any iron-type golf club having a static
loft angle that is greater than 45.degree.. Any of the disclosure
described herein in relation to a wedge or wedge-type golf club can
be embodied in any of various wedges having different loft angles,
such as a pitching wedge, gap wedge, sand wedge, lob wedge, flop
wedge, and/or wedges having static loft angles of 46.degree.,
48.degree., 50.degree., 52.degree., 54.degree., 56.degree.,
58.degree., 60.degree., greater than 60.degree., and any other
angles greater than 45.degree.. The disclosed technology can also
be embodied in iron-type golf clubs having static loft angles of
45.degree. or less, such as a 9-iron or lower-numbered irons.
[0013] In disclosed embodiments, the club head and the butt end of
the shaft have increased mass compared to a conventional club of
the same loft and style. Such clubs can have an increased overall
total mass as compared to a conventional club of similar type, and
can have an increase in the moment of inertia (MOI) of the club
about the CG and/or about the hand grip fulcrum location (e.g.,
where the club pivots when a golfer rotates his hands/wrists). The
increase in MOI can provide increased swing stability during a
swing stroke, decreasing unintentional waggling about the CG and
hand grip fulcrum, and thus providing increased accuracy and
precision to shots. In addition, the increase in MOI, and in
particular the increase provided by the added mass in the club
head, can provide greater momentum and stability as the club head
travels through turf, sand, or other material, leading to less
disruption of the path, orientation, and velocity of the club
head.
[0014] At the same time, the added weight in the club head and the
added weight in the butt end of the shaft can counterbalance each
other in such a way that the overall swingweight of the club (e.g.,
rotational moment about the hand grip fulcrum location due to
gravity) can be about the same as for a conventional,
non-counterbalanced club having significantly less total mass.
Having the same or similar swingweight can provide the golfer a
familiar feel and sensation during a swing that makes the disclosed
clubs readily playable in place of a conventional club without
having to adjust one's swing.
Club Length Dimensions
[0015] FIG. 1 shows a conventional wedge-type golf club 10 and
illustrates an exemplary methodology for measuring club length
dimensions based on the center of gravity (CG) and other features
of the club. Club 10 has a shaft 14 that couples its grip 16 to its
head 12. The overall shaft length (L.sub.1) of the club 10 can be
measured from a point 18 where the shaft center axis intersects the
bottom/sole of the head 12 to the butt end 20 of the club. A
dimension "d.sub.1" can be defined as the distance from the CG to
the lower shaft axis intersection point 18 and a dimension
"c.sub.1" can be defined as the distance from the CG to the butt
end 20 of the club.
[0016] Club Swingweight
[0017] FIG. 1 also illustrates a methodology for calculating the
swingweight of a golf club. The club 10 has a hand grip fulcrum
point 22, which is an approximation of the pivot point about which
a club pivots when a golfer holding the club rotates his
hands/wrists. The fulcrum point 22 can be defined as being a
predetermined distance "e" from the lower shaft axis intersection
point 18 along the shaft axis. For example, the distance "e" can be
defined as 30 inches. The swingweight of the club can then be
defined as the moment about the fulcrum point 22 caused by gravity
when the club is horizontal and fixed at the fulcrum point. This
swingweight moment "M.sub.e" can be calculated as the product of
the gravitational force "Fab" multiplied by the distance from the
CG to the fulcrum point 22, which is equal to the distance "e"
minus the distance "d.sub.1". F.sub.club is equal to the total mass
"m" of the club multiplied by the gravitational constant "g". Thus,
M.sub.e=(e-d.sub.1)*m*g. Accordingly, changing the total mass of a
club and/or shifting the location of the CG along the shaft axis
(changing the distance "d.sub.1") can change the swingweight of the
club and cause the club to feel different when held and during a
swing. Thus, it can be desirable to provide a club that maintains a
similar swingweight compared to conventional clubs such that a
golfer is provided with a familiar feel and sensation when
switching to a new club. In some embodiments, the swingweight can
be maintained at a similar level when additional mass is added to
the club by increasing the mass at the butt end of the club, which
shifts the CG toward the butt end of the club and increases
d.sub.1, thereby counterbalancing a smaller amount of mass added to
the club head.
Club MOI
[0018] The moment of inertia (MOI) of a wedge or other iron-type
golf club can be determined based on a selected axis perpendicular
to the shaft. The MOI about a given axis provides a measure of the
club's inertial resistance to rotating about that axis. For
example, the MOI of the club 10 about an axis extending
perpendicular to the shaft axis (e.g., perpendicular to the page in
FIG. 1) and passing through the CG of the club is referred to as
the "MOI.sub.CG" of the club 10. Similarly, the MOI of the club 10
about an axis extending perpendicular to the shaft axis and passing
through the grip fulcrum point 22 is referred to as the "MOI.sub.e"
of the club.
[0019] Calculating the true MOI of a club about any axis can be
difficult. One method of calculating the MOI of a club about a
selected axis is by measuring the undamped period of oscillation of
the club while it is fixed to a torsional spring of a testing
machine at a point where the selected axis intersects the shaft
axis, with the torsional spring being aligned with the selected
axis. The overall MOI of the system (club plus torsional spring
fixture) can then be calculated using the formula
MOI=(k*T.sup.2)/(4.pi..sup.2), where "k" is the coefficient of the
torsional spring, and T is the undamped period of oscillation of
the whole system. The MOI of the club about the selected axis is
then equal to the overall MOI of the system minus the MOI of the
torsional spring fixture by itself. Thus, the MOI of the club about
the selected axis can be calculated as
MOI.sub.club=(k/4.pi..sup.2)*(T.sup.2-(T.sub.fixt).sup.2), where
"T.sub.fixt" is the period of oscillation of the torsional spring
fixture by itself without a club fixed to it. T.sub.fixt can be a
known value for a given MOI testing system. Using such a testing
system and method, the MOI of the club about any axis intersecting
the shaft can be calculated, such as the MOI.sub.CG or the
MOI.sub.e.
[0020] MOI values for a club can also be approximated, such as by
assuming the mass of the shaft and grip are negligible and
representing the club head as a point mass at the center of the
head. The MOI about a given axis perpendicular to and intersecting
the shaft axis can then be approximated as the mass of the club
head multiplied by the square of the distance from the center of
the head to the given axis. This is illustrated in FIG. 1 for the
club 10. The club head 12 has a center 24 (e.g., CG of the head or
geometric center of the head, etc.) and the distance from the
center 24 to the grip fulcrum point 22 is shown as "X.sub.1", such
that the MOI.sub.e of the club 10 about the grip fulcrum axis 22
can be approximated as the mass "N.sub.1" of the head 12 multiplied
by the square of the distance "X.sub.1", or
N.sub.1*X.sub.1.sup.2.
Exemplary Counterbalanced Clubs
[0021] FIG. 2 shows an exemplary counterbalanced wedge-type golf
club 50 that comprises a head 52, a shaft 54, a grip 56, and a
counterbalance weight 57 at or near the butt end of the club. The
overall length "L.sub.2" of the club 50 is measured from the lower
shaft axis intersection point 58 to the butt end 60 of the club,
which can be the end of the counterbalance weight 57. The
MOI.sub.CG of the club 50 can be increased due the presence of the
counterbalance weight 57 and/or additional mass added to the club
head. The MOI.sub.e of the club 50 about the fulcrum point 62 can
also be increased. Note that the fulcrum point 62 is the same
predetermined distance e (e.g., 30 inches) from the lower shaft
axis intersection point 58 as in the conventional club 10.
[0022] The MOI.sub.e of the club 50 can be approximated as the sum
of the inertial effect of the head 52 and the inertial effect of
the counterbalance weight 57. As described above, the inertial
effect of the head 52 can be approximated as N.sub.2*X.sub.1.sup.2,
where "N.sub.2" is the mass of the head 52. Similarly, the inertial
effect of the counterbalance weight 57 can be approximated as
N.sub.3*X.sub.2.sup.2, where "N.sub.3" is the mass of the
counterbalance weight 57 and "X.sub.2" is the distance from the
center 66 of the counterbalance weight to the grip fulcrum point
62, as shown in FIG. 2. Thus, the MOI.sub.e of the club 50 can be
approximated as the sum of
(N.sub.2*X.sub.1.sup.2)+(N.sub.3*X.sub.2.sup.2).
[0023] The MOI.sub.CG of the club 50 can be approximated in a
similar manner using analogous dimensions from the mass centers 64
and 66 to the CG. The MOI.sub.e and MOI.sub.CG of the club 50 will
therefore be greater than the MOI.sub.e and MOI.sub.CG of the club
10 if the mass of their heads are equal or if the mass of the head
52 of club 50 is greater than the mass of the head 12 of club 10.
The greater MOI.sub.e and/or greater MOI.sub.CG of the club 50 can
provide greater swing stability during a swing and can make it more
difficult for a golfer to accidentally adjust the swing path of the
club when it is in motion, giving the golfer more consistent,
predictable ball striking. This also gives the club head more
inertial resistance while traveling through turf, sand, or other
material prior to striking the ball, thereby maintaining swing
speed and swing path.
[0024] While an increase in MOI.sub.e and/or MOI.sub.CG is
desirable, it can also be desirable to increase the mass of the
club head and/or maintain the same or similar swingweight compared
to a conventional club 10. To add mass to the club head 52 and add
mass to the butt end of the club in the form of the counterbalance
weight 57, it may be desirable to subtract mass from elsewhere in
the club so the club does not become too heavy and feel awkward to
the golfer. For example, the mass of the shaft and/or the mass of
the grip can be reduced to accommodate the added mass of a
counterbalance weight and the added mass in the club head. In some
embodiments, a lightweight shaft can be used instead of a
conventional shaft. For example, the shaft can comprise
substantially all graphite and/or other lightweight materials. In
another example, a bi-matrix shaft can be used that comprises
graphite and/or other lightweight material in an upper portion and
steel and/or other strong, plastically deformable material in a
lower portion or tip portion to allow the tip portion to be
plastically bent to adjust the orientation of the head relative to
the shaft axis. The grip can also be comprised of lightweight
material and/or can be reduced in volume to reduce its mass
contribution to the club. By reducing the mass of the shaft and/or
grip, more mass can be added to the club head and counterbalance
weight without making the club overly heavy.
[0025] The counterbalance weight 57 can comprise any dense
material, can have any shape, and can be coupled to the shaft
and/or grip in any manner. In some embodiments, the counterbalance
weight can be adjustable and/or removable. In some embodiments, two
or more counterbalance weights can be provided to allow a user to
select which one to couple to the club. For example, the different
counterbalance weights can have different masses, different shapes,
different lengths, and/or different aesthetic appearances. A person
may be able to remove one weight from the shaft and attach another
weight to the shaft to change the characteristics of the club. In
some embodiments, two or more counterbalance weights may be
attached to the club at the same time, such as one on top of the
other or side-by-side, etc. For example, a first weight may attach
to the shaft and a second weight may attach to the first weight. In
some embodiments, the different weights can appear identical, but
have different masses (e.g., different materials and/or hollow
regions). In some embodiments, the counterbalance weights can
require a tool to be removed from the club or to be secured to the
club, while in other embodiments no tool is required. When attached
to the club, the counterbalance weights may be non-adjustable or
may be adjustable.
[0026] In embodiments where a counterbalance weight is adjustable
when attached to the club, the axial position of the counterbalance
weight relative to the shaft and/or grip may be adjusted. For
example, the counterbalance weight may be adjustable along the
shaft axis by rotating the counterbalance weight relative to the
shaft. A threaded attachment with the shaft may be used, for
example. In some embodiments, the positional adjustability can be
limited to a group of discrete positional settings, rather than a
continuous or analog range of positions. In such embodiments, the
weight can be fixable at each of the discrete positional settings,
such as by using a tool to tighten a set screw, or the like.
[0027] FIGS. 3 and 4 are cross-sections of exemplary butt ends of
clubs that include a counterbalance weight. FIG. 3 shows a club 70
that comprises a shaft 72, a grip 74 mounted around the top end of
the shaft, and an external counterbalance weight 76 mounted around
the top end of the grip. In this example, the grip 74 includes a
thin or narrowed upper and a top portion 82 that extends around the
top end of the shaft 72. The counterbalance weight 76 has a recess
that receives the upper portion 80 and top portion 82 of the grip.
The counterbalance weight 76 can have a top portion 84 that covers
the top portion 82 of the grip and forms the upper surface of the
club 70. The grip can be secured to the shaft with an adhesive or
other means, and the counterbalance weight can be secured to the
grip with an adhesive or other means.
[0028] A counterbalance weight can have a radial outer surface that
is substantially contiguous with and/or blends into the radial
outer gripping surface of the grip, such that a smooth transition
is formed at an annular joint 78 (see FIG. 3) between the radial
outer surfaces of the grip and the weight. In some embodiments, the
appearance of the grip and the weight can be similar such that the
transition at the joint 78 is minimally noticeable visually or
tactiley, while in other embodiments, they may have different
colors or finishes such that the transition at the joint 78 is
visually noticeable but minimally noticeable by feel. As shown in
FIG. 3, the counterbalance weight may increase in diameter or width
moving upwardly from the joint 78. This can provide more volume and
mass per vertical length of the counterbalance weight.
[0029] FIG. 4 is a cross-sectional side view of the butt end of
another exemplary club 90 that has an internal counterbalance
weight 96. The club 90 comprises a shaft 92, the counterbalance
weight 96 mounted to the top end of the shaft, and a grip 94
mounted around the top end of the shaft and covering the
counterbalance weight, including a grip top portion 100 positioned
over the top of the weight 96. The weight 96 includes a lower
portion 98 that is inserted into and secured to the top end of the
shaft, such as by threads, friction fit, welding, adhesive, etc. In
this embodiment, substantially the entire outer surface of the butt
end of the club 90 is provided by the grip 94. The weight 96 can
have about the same diameter as the shaft 92, such that the weight
effectively extends the length of the shaft.
[0030] In any of the embodiments disclosed herein, the
counterbalance weight can have any axial length, provided the width
and density of it are sufficient to provide the desired mass
addition to the butt end of the club. In some circumstances, it may
be undesirable for the butt end of a club to extend too far above
the golfer's hands. For example, rules may prohibit the butt end of
the club from contacting or being anchored to the golfer's torso or
other body portion other than the hands. Further, the butt end of
the club may undesirably contact the golfer's legs or other body
part during a swing if it projects too far above the golfer's
hands. Thus, a shorter counterbalance weight can be desirable. To
provide a maximum mass per axial length added to the club, the
counterbalance weight can be made wider (e.g., as wide as the grip
or wider) and can be made from a relatively dense material, such as
steel, tungsten, or other dense metals. In some embodiments, the
axial length of the counterbalance weight is less than four inches,
less than 3 inches, less than 2 inches, and/or less than 1 inch.
The overall length "L.sub.2" of a counterbalance wedge-type clubs
as described herein including a counterbalance weight can be less
than or equal to 40 inches, less than or equal to 39 inches, less
than or equal to 38 inches, less than or equal to 37 inches, and/or
less than or equal to 36 inches.
[0031] The mass added to the club head 52 can be added in any
manner. In some embodiments, one or more adjustable and/or
removable weights can be coupled to the club head. Such weights may
be removable and interchangeable with other weights having
different masses. In other embodiments, the size and/or materials
of the club head may be changed to increase the mass of the club
head a desired amount.
[0032] The disclosed counterbalanced clubs can have any overall
mass, though in some embodiments the overall mass of the club,
including any weights, can be at least about 400 grams, at least
about 450 grams, at least about 475 grams, at least about 500
grams, and/or at least about 525 grams.
[0033] The counterbalance weight(s) itself can also have any mass,
though in some embodiments the mass of the counterbalance weight is
at least about 25 grams, at least about 40 grams, at least about 50
grams, at least about 70 grams, and/or at least about 100
grams.
[0034] The mass of the club head can be, for example, at least
about 280 grams, at least about 300 grams, at least about 310
grams, at least about 320 grams, and/or at least about 340
grams.
[0035] The mass added to the club head, whether in the form of one
or more weights movable relative to the head body or increased mass
of the head body, can be at least 5 grams, at least 8 grams, at
least 10 grams, and/or at least 15 grams. In one particular
example, the club head has a total mass of about 309 grams,
including added mass in the form of one or more weights that have a
mass of about 9 grams, while the counterbalance weight has a mass
of about 50 grams.
[0036] The shaft can have any mass, such as 130 grams or less, 100
grams or less, 80 grams or less, 70 grams or less, and/or 60 grams
or less. In one particular example, a bi-matrix shaft is included
that has a graphite upper portion with a mass of about 50 grams and
a steel lower portion with a mass of about 20 grams, providing a
total of about 70 grams.
[0037] The grip can also have any mass, such as 100 grams or less,
50 grams or less, 40 grams or less, and/or 35 grams or less. In
some embodiments, the grip comprises a lightweight EVA
material.
[0038] The total mass of the shaft and grip together can be lower
than in a conventional club, such as less than 200 grams, less than
150 grams, less than 125 grams, less than 110 grams, and/or less
than 100 grams.
[0039] The disclosed counterbalance clubs can have any MOI.sub.CG,
such as at least 500 kg*cm.sup.2, at least 525 kg*cm.sup.2, at
least 550 kg*cm.sup.2, at least 575 kg*cm.sup.2, at least 600
kg*cm.sup.2, and/or at least 625 kg*cm.sup.2. Similarly, the
disclosed counterbalance clubs can have any MOI.sub.e (with e=30
inches), such as at least 2000 kg*cm.sup.2, at least 2025
kg*cm.sup.2, at least 2050 kg*cm.sup.2, at least 2075 kg*cm.sup.2,
at least 2100 kg*cm.sup.2 and/or at least 2200 kg*cm.sup.2.
[0040] Another meaningful parameter type for counterbalanced golf
clubs are ratios of a club moment of inertia divided by the club
length squared (L.sup.2). For example, the ratio MOI.sub.CG per
unit length.sup.2 (in units of kg*cm.sup.2/inch.sup.2) for the
disclosed counterbalance clubs can be from about 1.4:1 to about
1.1:1, from about 1.35:1 to about 1.15:1, and/or from about 1.3:1
to about 1.2:1.
[0041] Yet another meaningful parameter for counterbalanced golf
clubs are ratios of a club moment of inertia divided by the total
club mass. For example, the ratio MOI.sub.CG per unit mass (in
units of kg*cm.sup.2/g) for the disclosed counterbalance clubs can
be at least 1.05, at least 1.10, at least 1.15, at least 1.20, and
or at least 1.23.
[0042] Still another meaningful parameter type for counterbalanced
clubs is the ratio of the MOI.sub.CG per unit length.sup.2 divided
by the total club mass. This parameter can be expressed in terms of
a unitless percentage and can be referred to as "inertial
efficiency" since it represents how effectively the mass and length
of the club are utilized to maximize the MOI.sub.CG. The disclosed
counterbalance clubs can have an inertial efficiency of at least
13%, at least 13.3%, at least 13.5%, at least 13.8%, at least
14.0%, at least 14.2%, at least 14.4%, at least 14.6%, at least
14.8%, and/or at least 15.0%.
[0043] The disclosed counterbalance clubs can have a swingweight
that is similar to a conventional club of the same type having less
mass. For example, the disclosed counterbalance clubs can have a
swingweight (with e=30 inches) of less than 3.0 N*m, less than 2.8
N*m, less than 2.7 N*m, greater than 2.6 N*m, greater than 2.64
N*m, greater than 2.68 N*m, between 2.5 N*m and 3.0 N*m, between
2.6 N*m and 2.8 N*m, between 2.63 N*m and 2.75 N*m, and/or between
2.66 N*m and 2.70 N*m.
[0044] Table 1 below provides representative data for two different
exemplary wedges. Wedge A is an exemplary embodiment of the
counterbalanced clubs described herein, having a 58.degree. loft.
Wedge B is an exemplary conventional wedge having the same
58.degree. loft and same general style as Wedge A, but without a
counterbalance weight at the butt end of the shaft and less club
head mass. As shown in Table 1, Wedge A is slightly longer than
Wedge B due to the counterbalance weight added to the butt end of
the shaft. Wedge A also has a greater mass, greater MOI.sub.CG, and
greater inertial efficiency than Wedge B. However, Wedges A and B
have about the same swingweight.
TABLE-US-00001 TABLE 1 Sole- MOI.sub.CG per Inertial Length to-CG
Mass MOI.sub.CG Unit Mass Efficiency Swingweight Wedge (in) (in)
(g) (kg * cm.sup.2) (kg * cm.sup.2/g) (unitless) (N * m) A 35.75
9.50 527 647 1.23 14.9% 2.693 B 35 7.55 471 489 1.04 13.2%
2.632
Ground Interaction
[0045] FIGS. 5 and 6 illustrate the interaction of an exemplary
wedge 100 with the ground 104 during a swing prior to and just
after striking a ball 102. FIG. 5 shows the head of the wedge 100
just prior to contacting the ground 104, while FIG. 6 shows the
head of the wedge 100 contacting the ball 102 after traveling
through a section of the ground 104.
[0046] FIG. 7 is a graph showing the depth of the lower surface of
the head of the wedge 100 below the surface of the ground 104 as a
function of time, for an exemplary 58.degree. counterbalanced
wedged (dashed line) and for a convention 58.degree. wedge of the
same general style (solid line), each traveling at 80 mph club head
speed relative to the ground. The data in FIG. 7 was generated
using a simulation method wherein the ground model is simulated
using smoothed particle hydrodynamics to represent soft sand,
wherein the solid mesh turns into particles when the solid mesh
reaches 0.01 strain and thereafter the particles interactions are
modeled. In the simulation, the counterbalanced wedge includes an
additional 40 gram counterbalance weight located 0.5 inches above
the butt end of the shaft (where the conventional shaft ends) and
an additional 10 grams of mass added to the club head compared to
the convention club head (via increased density), with the same
size club head in both wedge models. The same velocity conditions
were used with both wedge models.
[0047] As shown in FIG. 7, the counterbalanced wedge digs further
below the surface of the ground (about 10 mm, compared to about 9
mm for the conventional wedge), which illustrates that the
counterbalanced wedge has more downward momentum and is less
impeded by the ground. In addition, the counterbalanced wedge
rebounds from the lowest point quicker than the conventional wedge
and also exits the ground (displacement >0) slightly sooner than
the conventional wedge, again illustrating less disruption from the
ground. Because the counterbalanced wedges as disclosed herein have
greater inertia and suffer less disruption from the ground prior to
striking the ball, compared to conventional wedges, the
counterbalanced wedges provide more consistent, accurate ball
striking and maintains a greater velocity while traveling through
the ground, leading to greater shot distances.
Exemplary Materials
[0048] The components of the embodiments disclosed herein can be
formed from any of various suitable metals, metal alloys, polymers,
composites, or various combinations thereof.
[0049] In addition to those noted elsewhere herein, examples of
metals and metal alloys that can be used to form the components
include, without limitation, carbon steels (e.g., 1020 or 8620
carbon steel), stainless steels (e.g., 304 or 410 stainless steel),
PH (precipitation-hardenable) alloys (e.g., 17-4, C450, or C455
alloys), titanium alloys (e.g., 3-2.5, 6-4, SP700, 15-3-3-3,
10-2-3, or other alpha/near alpha, alpha-beta, and beta/near beta
titanium alloys), aluminum/aluminum alloys (e.g., 3000 series
alloys, 5000 series alloys, 6000 series alloys, such as 6061-T6,
and 7000 series alloys, such as 7075), magnesium alloys, copper
alloys, nickel alloys, and tungsten.
[0050] Examples of composites that can be used to form the
components include, without limitation, glass fiber reinforced
polymers (GFRP), carbon fiber reinforced polymers (CFRP), metal
matrix composites (MMC), ceramic matrix composites (CMC), and
natural composites (e.g., wood composites).
[0051] Examples of polymers that can be used to form the components
include, without limitation, thermoplastic materials (e.g.,
polyethylene, polypropylene, polystyrene, acrylic, PVC, ABS,
polycarbonate, polyurethane, polyphenylene oxide (PPO),
polyphenylene sulfide (PPS), polyether block amides, nylon, and
engineered thermoplastics), thermosetting materials (e.g.,
polyurethane, epoxy, and polyester), copolymers, and elastomers
(e.g., natural or synthetic rubber, EPDM, and Teflon.RTM.).
[0052] In view of the many possible embodiments to which the
principles of the disclosed technology may be applied, it should be
recognized that the illustrated embodiments are only examples and
should not be taken as limiting the scope of the disclosure.
Rather, the scope of the disclosure is at least as broad as the
following exemplary claims. We therefore claim all that comes
within the scope of the following claims.
* * * * *