U.S. patent application number 09/769200 was filed with the patent office on 2002-04-25 for golf club having angular grooves.
Invention is credited to Doolen, Shaun R..
Application Number | 20020049096 09/769200 |
Document ID | / |
Family ID | 23283336 |
Filed Date | 2002-04-25 |
United States Patent
Application |
20020049096 |
Kind Code |
A1 |
Doolen, Shaun R. |
April 25, 2002 |
Golf club having angular grooves
Abstract
A method of imparting a directional corrective horizontal spin
component to a golf ball includes providing a plurality of golf
clubs each having a golf club head with a ball striking face having
grooves angled relative to a sole of the club. Each club has a
select loft angle and a groove angle which varies as a function of
the select loft angle. The method further includes selecting a club
having a desired loft angle for striking a golf ball, aligning the
club head with the sole perpendicular to a desired line between the
ball and the target and striking the golf ball with the sole
perpendicular to the desired line between the ball and the
target.
Inventors: |
Doolen, Shaun R.; (Aurora,
CO) |
Correspondence
Address: |
SWANSON & BRATSCHUN L.L.C.
1745 SHEA CENTER DRIVE
SUITE 330
HIGHLANDS RANCH
CO
80129
US
|
Family ID: |
23283336 |
Appl. No.: |
09/769200 |
Filed: |
January 24, 2001 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09769200 |
Jan 24, 2001 |
|
|
|
09328984 |
Jun 9, 1999 |
|
|
|
Current U.S.
Class: |
473/330 |
Current CPC
Class: |
A63B 53/047 20130101;
A63B 53/005 20200801; A63B 53/04 20130101; A63B 60/00 20151001;
A63B 53/0445 20200801 |
Class at
Publication: |
473/330 |
International
Class: |
A63B 053/04 |
Claims
I claim:
1. A method of imparting a directional corrective horizontal spin
component to a golf ball, the method comprising: providing a
plurality of golf clubs, each club comprising a shaft and a club
head, each club head having a heel attached to one end of the
shaft, a toe opposite the heel and a sole defining the bottom of
the club head extending between the heel and the toe, the club head
further including a ball-striking face with an intended impact area
covering part of the face and extending continuously across the
face from near the heel to near the toe, the intended impact area
having a plurality of grooves therein, each groove extending at a
groove angle relative to the sole, each club head further having a
select loft angle, the groove angle for each club head being a
function of the select loft angle; selecting a club having a
desired loft angle for striking a golf ball; aligning the club head
with the sole perpendicular to a desired line between the ball and
the target; and striking the golf ball with the sole perpendicular
to the desired line between the ball and a target.
2. The method of claim 1 further comprising providing alignment
indicia on the club face parallel to the club sole and aligning the
club head with the alignment indicia perpendicular to the desired
line between the ball and the target.
3. The method of claim 1, wherein the grooves are substantially
straight lines.
4. the method of claim 1, wherein each face has a heel and a toe
and the grooves are angled such that each groove runs from an upper
face section positioned relatively toward the toe to a lower face
section positioned relatively toward the heel.
5. The method of claim 1, wherein the face has a heel and a toe and
the grooves are angled such that each groove runs from an upper
face section positioned relatively toward the heel to a lower face
section positioned relatively toward the toe.
6. The method of claim 1, wherein the golf clubs are irons having
grooves angled from a lower heel portion to an upper toe portion
having loft angles and corresponding groove angles in the following
ranges:
6 LOFT ANGLE (.degree.) GROOVE ANGLE (.degree.) 40-55 10-20 30-40
10-30 15-30 25-45
7. The method of claim 1, wherein as between golf club heads the
groove angle increases as the select loft angle decreases.
8. The method of claim 1, wherein the golf clubs are woods having
grooves angled from a lower heel portion to an upper toe portion
having loft angles and corresponding groove angles in the following
ranges:
7 LOFT ANGLE (.degree.) GROOVE ANGLE (.degree.) 5-20 10-30 >15
20-45
9. A set of golf clubs comprising: a plurality of golf clubs, each
club comprising a shaft and a club head, each club head having a
heel attached to one end of the shaft, a toe opposite the heel and
a sole defining the bottom of the club head extending between the
heel and the toe, the club further including a ball-striking face
with an intended impact area covering part of the face and
extending continuously across the face from near the heel to near
the toe, the intended impact area having a plurality of grooves
therein, each club head further having a select loft angle, wherein
at least two of the golf clubs have club heads have alignment
indicia on the club face defining a horizontal line and the grooves
of the at least two golf club heads extend a groove angle relative
the horizontal line defined by the alignment indicia, the groove
angle for each such club head being a function of the select loft
angle.
10. The set of golf clubs of claim 9, wherein the grooves of the at
least two club heads extend parallel continuously from an upper
face section positioned relatively toward the toe to a lower face
section positioned relatively toward the heel.
11. The set of golf clubs of claim 9, wherein as between the at
least two golf club heads the groove angle increases as the select
loft angle decreases.
12. The set of golf clubs of claim 9, wherein all the club heads
have the reference indicia and angled grooves and for club heads
having a loft angle less than 56.degree., the grooves extend in
parallel continuously from a lower face section positioned
relatively toward the toe to an upper face section positioned
relatively toward the heel.
13. The set of golf clubs of claim 9, wherein for the at least two
club heads the range of groove angles corresponds to the range of
loft angles as follows:
8 CLUB TYPE LOFT ANGLE (.degree.) GROOVE ANGLE (.degree.) Irons
40-55 10-20 30-40 10-30 15-30 25-45 Drivers 5-15 10-45 Fairway
Woods >15 20-45
14. A method of making a golf club having a club head with a ball
striking face having parallel grooves therein for imparting a
corrective spin on golf balls struck by a golfer, the method
comprising: measuring an unwanted spin imparted by the golfer in
hitting a golf ball; determining an angle for the grooves to be
inclined relative to a leading edge of the club head to impart a
spin correcting the unwanted spin; and forming the grooves in the
club head face at the determined angle relative to a leading edge
of the club head.
Description
FIELD OF THE INVENTION
[0001] This application is a continuation-in-part of copending U.S.
application Ser. No. 09/328,984 filed on Jun. 9, 1999. The present
invention relates to the field of golf, and more particularly to
golf clubs that impart corrective spin on a golf ball to impart
desired flight characteristics.
BACKGROUND
[0002] The sport of golf has a long history and is enjoyed by many
participants throughout the United States and the world. The sport
is well known and need not be described in detail except as is
necessary to describe the present invention. Briefly, a player
strikes a golf ball with a golf club. The golf club includes a
shaft gripped by the player ("golfer"), to which is attached a golf
club head which strikes the ball. The portion of the head that
strikes the ball is called the "face," which is a generally planar
surface. The bottom perimeter of the golf club face (as defined
when the club is used in its intended manner to strike the ball) is
called the "sole." It is noted here that the golf clubs relevant to
the present invention are all "distance" clubs, as opposed to
"putters," which are used in a substantially different manner from
distance clubs and which are not relevant to the present
invention.
[0003] A phenomenon all too familiar to most recreational golfers
and even professional golfers is the "slice," which is a
description of the path of a golf ball that moves in an increasing
curve away from a golfer in the direction the golfer is facing.
While it is in some cases be desirable to slice the ball, a slice
is much more commonly the result of flaws in the golfer's swing.
Slicing the ball misdirects the ball from its intended trajectory,
which can frustrate the golfer and prevent the golfer from
obtaining a satisfactory score.
[0004] A slice is caused by a horizontally glancing blow of the
club, which imparts spin. Such a glancing blow is influenced by the
club face angle and by the swing path at the moment of impact. To
avoid a slice, the face angle and the swing path should be at right
angles at the absolute point of impact, which imparts a back spin
about a horizontal axis perpendicular to the desired line of
travel. The ball therefore rotates in a clockwise manner in
relation to the vertical axis of the golfer, from the golfer's
perspective. However, because the club head carries the ball
somewhat during and immediately after impact, there is a high
likelihood of imparting a horizontal component to the spin, in
essence tipping the desired horizontal axis clockwise from a
perspective behind the ball facing the direction of travel so that
a slicing spin results.
[0005] A related phenomenon is the "hook," which is a description
of the path of a golf ball that moves in a curve away from the
direction the golfer is facing. With a hook, axis of rotation is
tipped counter-clockwise when viewed from behind the ball facing
the direction of travel. Because of the swing path of a typical
golfer, hooking is much less common than slicing. Like the slice,
the hook is sometimes intended but it more often unintended, and
can also prevent a golfer from achieving a good score. However, the
difficulty of hooking the ball and its perceived aesthetics are
such that sometimes a golfer will attempt to hook the ball, in a
shot called a "draw." The ability to make a draw show is often a
source of accomplishment to the golfer.
[0006] As discussed above, in addition to a horizontal spin
component that would cause a slice or hook, a struck golf ball
generally also has a backspin. The spinning ball rises because of
the Magnus Effect (as described in more detail herein), thus
affecting the trajectory. More backspin results in a higher
trajectory. Additionally, backspin aids in the ability to stop the
ball on the green without excess roll.
[0007] A number of different golf clubs are used by a golfer
depending upon the position of the ball on the course and its
distance to the hole. Typical golf clubs are a set of "woods," a
set of "irons" in the range of 1-9, and several of wedges. The
difference between the clubs (within a class of clubs) are the
"loft" of the golf head, which is the angle between the club head
face and the axis of the shaft, and the length of the shaft. The
higher lofted clubs typically have shorter shafts; the combination
of high loft and a short shaft results in greater backspin.
[0008] A consequence of the longer shaft lengths of the lower
lofted clubs is increased head speed. This is because such a club
is swung in an arc of greater radius than a shorter club. The
increased head spin increases the horizontal spin and exaggerates a
slice (or a hook).
[0009] Presently, all commercially available clubs known to the
inventor have grooves in the club face that are parallel to the
club face sole. Such grooves increase the friction between the club
face and the ball and therefore increase the spin imparted to the
ball. While such grooves are useful for increasing backspin, they
do not assist in imparting a desired horizontal spin that could
correct for a hook or slice.
[0010] U.S. Pat. No. 5,785,610 of Birmingham (1998) describes a
golf club having grooves in a what is a described as a "chevron"
pattern. The chevron pattern grooves may serve to impart horizontal
spin to the ball. However, the chevron pattern is not believed to
be useful because it assumes that horizontal spin that is imparted
on the ball is solely a function of the portion of the club face
that the impacts the ball. It therefore has grooves of different
angular slopes across the club face. It is believed that the
chevron pattern is not effective in reducing slice, and further,
even if grooves of different slope across the club face are used,
the slopes should not be as shown in the Birmingham patent.
[0011] Japanese patent publication no. JP9299518 A2 to Hideaki
discloses a set of iron clubs having grooves on the club face which
are inclined plus or minus 15.degree. from a phantom horizontal
reference line. The angle of the grooves decreases by 1.degree. to
3.degree. successively as the club number (or loft angle)
increases. Hideaki teaches that the inclined grooves are used as an
alignment device by a golfer to help compensate for errors in the
golfer's swing. When a golfer addresses a ball, the parallel lines
are aligned perpendicular to a line between the ball and an
intended target area. The intent is that when a golfer makes an
ordinary swing the club face will be properly aligned to drive a
golf ball closer to the intended target area. Because the grooves
of the Hideaki reference are intended for use as an alignment aid,
there is no teaching or suggestion of stroking a ball with the
grooves at an angle relative to a leading edge or sole of the club
for imparting a corrective spin on a ball.
[0012] Japanese patent publication JP2005980 A2 to Sheihei
discloses a wood golf club head having inclined grooves forming an
angle of about 90.degree. with a golf club shaft. This provides
grooves which are inclined between a lower heel portion and lower
toe portion about 3720 -35.degree. from a leading edge of a club.
The '980 publication teaches that the purpose of these grooves is
to minimize slicing and induce a high trajectory, draw type drive.
The '980 publication teaches only providing a single club with a
select groove angle. Thus, the '980 publication does not teach
varying the groove angle to vary the amount of corrective spin
applied to a ball as between clubs of different loft angles.
[0013] An understanding of the principles behind the present
invention requires an understanding of the "Magnus Effect." This
well understood effect is a particular manifestation of Bernoulli's
theorem that fluid pressure decreases as fluid speed increases.
This effect explains the "curve" of rotating balls such as
baseballs and golf balls. Pressure differences develop in a fluid
through which a spinning sphere moves. Greater pressure on the side
where the airflow is slowed down forces the ball in the direction
of the low-pressure region on the opposite side, where there is a
relative increase in airflow.
[0014] Finally, it should be noted that while the principles on
which the present invention is based are believed to be well
understood, the effectiveness of the present invention has been
verified through experiment and therefore the scope the invention
should not be limited by the validity of any scientific theory.
SUMMARY
[0015] The present invention is directed to a method of imparting a
corrective spin to a golf ball as well as a set of golf clubs for
imparting a corrective spin. Each club includes a golf club head
having a golf club face with a plurality of grooves. At least two
of the clubs have grooves which are angled across the face at an
angle that is substantially non-parallel with the club sole, the
grooves being sloped in the same direction as one another. The
purpose of the angled grooves is to impart a corrective spin on a
struck golf ball that counteracts a horizontal spin component
imparted by a glancing blow to a golf ball. The angle of the
grooves is preferably varied depending upon the loft angle of the
club. An advantage of the present invention is that slicing is
eliminated or greatly reduced, and a golfer can much more easily
draw the ball if desired. Alternatively, the grooves can be angled
to eliminate or reduce an unwanted hook.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIGS. 1A-1L are elevation views of the faces of a set of
golf clubs according to an embodiment of the present invention.
[0017] FIG. 2 is a schematic view illustrating the gear effect
according to an embodiment of the present invention.
[0018] FIG. 3 is a perspective view of a golfer illustrating
different swing arcs for different club heads.
[0019] FIG. 4 is an elevational view depicting decreasing shaft
length as the loft angle of club heads increases.
[0020] FIG. 5 is a view of a club head in accordance with the
present invention from the perspective of a golfer preparing to
strike a ball illustrating alignment of the club head before
striking the ball.
DETAILED DESCRIPTION
[0021] The present invention includes golf clubs having grooves
that are angled across the club face with respect to the sole of
the club. Currently used clubs have parallel grooves with respect
the sole of the club, which is defined to be an angle of zero
degrees herein.
[0022] Representative groove angles for a first embodiment of golf
clubs are shown in FIGS. 1A-1L, with reference to Table I
below.
1TABLE I FIGURE CLUB LOFT ANGLE (.degree.) GROOVE ANGLE (.degree.)
1B 1 Iron 17 45 1C 2 Iron 20 45 1D 3 Iron 24 45 1E 4 Iron 28 45 1F
5 Iron 32 40 1G 6 Iron 36 35 1H 7 Iron 40 30 1I 8 Iron 44 25 1J 9
Iron 48 20 1K P 52 10 Not Shown A 54 10 Not Shown S 56 10 1L L 60
-20 1A Woods 6-32 45
[0023] With reference to FIG. 1A, a club 10 having a face 12 with
an intended impact area 14 is shown. The intended impact area 14 is
the primary portion of the face 12 that would normally strike a
golf ball, and may be relatively larger or smaller than shown. A
plurality of grooves 16 traverse the impact area. In FIG. 1A, the
grooves angle from an upper toe section 18 toward a lower heel
section 20 at a 45 degree angle. In FIGS. 1B-1L, a number of
additional clubs are shown having grooves of different angles, as
can be determined with reference to TABLE I. For the loft wedge of
FIG. 1L, a negative slope (meaning the lines angle in the opposite
direction) is shown.
[0024] Table II below sets forth club number, loft angle and groove
angle for a second embodiment of golf club irons. Likewise, Table
III below sets forth the club number, loft angle and groove angle
for a third embodiment of golf club irons. Table IV sets forth
preferred groove angles for a driver for use by an amateur golfer
and a highly skilled or professional golfer. Table V sets forth
preferred ranges of groove loft angles for irons, drivers and
fairway woods.
2TABLE II CLUB LOFT ANGLE (.degree.) GROOVE ANGLE (.degree.) 2 15
25 3 18 25 4 21 25 5 24 25 6 27 25 7 32 25 8 34 20 9 38 15 PW 42
10
[0025]
3TABLE III CLUB LOFT ANGLE (.degree.) GROOVE ANGLE (.degree.) 1 18
33 2 20 32 3 23 31 4 26 30 5 30 29 6 34 28 7 38 25 8 42 20 9 46 15
PW 50 10 AW 52 5 SW 56 -10 LW 60 -20
[0026]
4TABLE IV CLUB LOFT ANGLE (.degree.) GROOVE ANGLE (.degree.) Driver
(Amateur) 10.5 28 Driver (Professional) 9.5 18
[0027]
5 TABLE V CLUB LOFT ANGLE (.degree.) GROOVE ANGLE (.degree.) Irons:
40-55 10-20 30-40 10-30 15-30 25-45 Drivers: 5-20 10-30 Fairway
Woods: >15 20-45
[0028] The angular groove design imparts a corrective horizontal
spin component to the ball, while still providing for the
availability of backspin. With reference to the schematic diagram
of FIG. 2, the angled grooves induce a gear effect as the club
impacts the ball. The ball is depressed into the grooves creating a
meshing of the grooves with the contacting portion of the ball. As
the club carries the ball forward, this gear effect causes an
angular spin which counteracts the golfer's slice. Whereas a
glancing blow of a slice tips the ideal horizontal axis of a
backspin clockwise from a perspective behind the ball facing the
target, the angled grooves and resulting gear effect essentially
tips the axis counter-clockwise from this same perspective, thereby
counteracting the effect of the slice and even possibly imparting a
draw. The higher degree of groove angle with the lower irons and
woods is generally desirable because the club head speed is faster
and greater corrective spin must be induced (the difference is
swing path between clubs is shown in FIG. 3). The mid irons (#4-6)
require a less steep groove angle because the swing place is
steeper and the club head speed is less. The approach irons and
wedges are the shortest length clubs and have the steepest swing
plane of the clubs. Therefore, the groove angle may be the least,
thus providing relatively more backspin and less corrective
horizontal spin.
[0029] The angled grooves 16 run across the impact area 14 of the
of the club face from an alignment line 21 which is generally
parallel to the sole or leading edge 22 to the top edge 24 of the
face 12. Alternatively, the angled grooves may extend from the sole
or leading edge 22 itself to the top edge 24. As an alternative to
the reference line 21, alignment dashes 26 or other indicia
defining a horizontal line corresponding to the alignment line may
be used (see FIG. 5). The angled grooves 16 are parallel with one
another. It can be appreciated that the grooves can traverse the
entirety of the club face 10, or a smaller portion of the club face
that corresponds to the impact area. They are preferably inclined
relative to the alignment indicia.
[0030] In one embodiment of the invention, the grooves are
structured to conform to the United States Golf Association rules,
the contents of which are incorporated by reference. Briefly
summarizing the rules as they currently stand, any rounding of the
groove edges shall be in the form of a radius which does not exceed
0.020 inches (0.5 mm); the groove width shall not exceed 0.035
inches (0.9 mm) using the thirty degree measurement method; the
distance between edges of adjacent grooves must not be less than
three times the width of a groove, and not less than 0.075 inches
(1.9 mm); and the depth of the grooves must not exceed 0.020 inches
(0.5 mm). It will be readily understood that these rules may be
changed over time, and thus the structure of a club according to
this embodiment could be correspondingly changed. While the above
parameters describe the maximum size and density of grooves, a club
according this embodiment could have smaller and/or less dense
grooves. The grooves may have any allowable shape, such as what are
known as "U" shaped grooves or "V" shaped grooves. Of course, the
standards of any other golfing organization besides the USGA could
also be adopted, so long as such rules do not prohibit grooves that
are angled with respect to the sole of the club.
[0031] In another embodiment of the invention, the grooves may be
structured so that they do not conform to the United States Golf
Association rules. In such an embodiment, the grooves could have
any shape, size, and density.
[0032] It should be appreciated that groove angles listed in the
above tables are merely illustrative embodiments of the invention
and are not intended to limit the scope of the invention, except as
to the specified embodiments. The precise angles are not
necessarily critical and deviations should also produce acceptable
results. Thus, it is contemplated that a club of a given loft might
be manufactured in a number of different versions of differing
groove angles, because the amount of corrective spin that is
desirably imparted on the ball depends to some extent upon the
swing of an individual golfer. However, it is believed that a
groove angle of at least 15.degree. is necessary to apply a
corrective spin to balls struck with an iron ranging from a two
iron (18.degree.-20.degree. loft) to a nine iron
(42.degree.-48.degree. loft). The present invention also
contemplates that a testing device could be provided to measure the
amount of unwanted side spin (slice or draw) imparted by a golfer,
and then corrective groove angles in the ranges set forth in Table
V could be provided on a customized basis to provide a required
amount of corrective spin. This could be accomplished by
determining groove angles necessary to impart a given corrective
spin as a function of unwanted spin and factors such as club head
speed or by trial and error in varying groove angles. The
deviations from the parameters listed in the tables may be minor,
such as several degrees, or major. In an example of a major change,
the groove angles may be sloped in the opposite direction (at any
angle) from that shown in FIG. 1A-K, as illustrated in FIG. 1L,
which would be useful for golfers who have an unusual tendency to
hook the ball. It will also be apparent that the depicted clubs are
"right-handed," and that the invention has equal applicability to
"left-handed" clubs.
[0033] The use of the clubs to impart a corrective spin is
illustrated in part by reference to FIG. 5. FIG. 5 is a view of a
club head from the perspective of a standing golfer addressing a
ball (not shown). The club head 10 is oriented with the alignment
dashes 26 (and the leading edge or sole of the club head) defining
a straight line illustrated by phantom line 28 perpendicular to an
intended line of travel 30 of the golf ball. Therefore, in use the
golfer would view an intended target area along the intended line
of travel 30 and orient the club with the alignment dashes
perpendicular to this intended line of travel. In this manner, the
grooves 24 are at an angle relative to the ball so as to impart the
corrective spin as discussed above when a golf ball is struck.
[0034] It will also be appreciated that a club could be constructed
according to the present invention but could have a different
appearance from these shown in FIGS. 1A-1L. For example, the
grooves 16 could be replaced with grooves that are not continuous.
Grooves could be used that would have some degree of curvature
(i.e., are not straight line segments). Or, a plurality of grooves
could be used that are not identical to one another in some
respects. None of these variations (or other variations that may be
apparent to those skilled in the art) should necessarily be deemed
to place such a club outside of the scope of the present invention.
The above described invention provides means of a club face to
achieve a corrective horizontal spin component to a golf ball, and
other equivalent means may fall within the inventive scope.
* * * * *