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| United States Patent |
6,179,725
|
|
Doolen
|
January 30, 2001
|
Golf club having angular grooves
Abstract
A golf club has grooves across its face that are angled from an upper face
section positioned relatively toward a toe of the club to a lower face
section positioned relatively toward the heel with respect to the sole of
the golf club instead of being parallel with a sole of the club. The
angled grooves cause a sideways spin to be imparted to a struck golf ball.
In one application, the angled grooves impart a spin that corrects for
what would otherwise be a slice. The grooves can be at different angles,
depending upon the golf club and the application. In an embodiment, the
low irons and woods will have the grooves at a relatively higher angle
than the mid irons, which will have the grooves at a higher angle than the
approach irons and wedges. Clubs having such angled grooves can be
structured according to USGA or other rules, but need not be.
| Inventors:
|
Doolen; Shaun R. (P.O. Box 5571, Vail, CO 81658)
|
| Appl. No.:
|
328984 |
| Filed:
|
June 9, 1999 |
| Intern'l Class: |
A63B 053/00; A63B 053/04 |
| Field of Search: |
473/330,331,289,324,287,290
D21/733,750,751
|
References Cited
U.S. Patent Documents
| D55278 | May., 1920 | Kraeuter.
| |
| D96478 | Aug., 1935 | Jansky.
| |
| D193098 | Jun., 1962 | Davis.
| |
| D210033 | Jan., 1968 | Johnston.
| |
| D346840 | May., 1994 | Fenton.
| |
| 2005401 | Jun., 1935 | Storz.
| |
| 2034936 | Mar., 1936 | Barnhart.
| |
| 4252262 | Feb., 1981 | Igarashi.
| |
| 4792140 | Dec., 1988 | Yamaguchi.
| |
| 5354059 | Oct., 1994 | Stuff.
| |
| 5688186 | Nov., 1997 | Michaels.
| |
| 5690531 | Nov., 1997 | Rowland et al.
| |
| 5785610 | Jul., 1998 | Birmingham.
| |
| Foreign Patent Documents |
| 9-131421 | May., 1997 | JP.
| |
Primary Examiner: Passaniti; Sebastiano
Attorney, Agent or Firm: Swanson & Bratschun LLC
Claims
I claim:
1. A set of golf clubs comprising:
at least two 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 groove 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.
2. The set of golf clubs of claim 1 wherein the grooves extend in parallel
continuously from an upper face section positioned relatively toward the
toe to a lower face section positioned relative toward the heel.
3. The set of golf clubs of claim 1 wherein as between golf club heads the
groove angle increases as the select loft angle decreases.
4. The set of golf clubs of claim 1 wherein each club head is an iron and
the groove angle varies with the loft angle as follows.
TBL
LOFT ANGLE (.degree.) GROOVE ANGLE (.degree.)
17 45
20 45
24 45
28 45
32 40
36 35
40 30
44 25
48 20
52 10
54 10
56 10
60 -20
5. The set of golf clubs of claim 1 wherein each club head is a wood and
each groove angle is about 45 degrees.
6. The set of golf clubs of claim 1 wherein each shaft has a length and the
length is a function of the loft angle.
7. The set of golf clubs of claim 6 where the shaft length decreases as the
loft angle increases.
8. The set of golf clubs of claim 1 wherein for clubs having a loft angle
of less than 56 degrees, the grooves extend in parallel continuously from
an upper face section positioned relatively toward the toe to a lower face
section positioned relatively toward the heel, and for clubs having a club
head that is an iron and a loft angle of object 60 degrees or greater, 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.
9. The set of golf clubs of claim 8 wherein for clubs having a club head
that is an iron and a loft angle of about 60 degrees or greater, the
groove angle is about 20 degrees.
10. The set of golf clubs of claim 1 wherein for club heads that have a
loft angle of less than about 56 degrees, the groove angle is between
about 10-45 degrees.
11. The set of golf clubs of claim 10 wherein the groove angle increases as
the loft angle decreases.
Description
FIELD OF THE INVENTION
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
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.
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.
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. However, because the club head carries the ball somewhat during
and immediately after impact, there is a high likelihood of imparting a
slicing horizontal spin.
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. 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.
In addition to a horizontal spin that would cause a slice or hook, a struck
golf ball generally also has a backspin, which is the spinning of the ball
in a clockwise manner in relation to the vertical axis of the golfer, from
the golfer's perspective. 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.
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.
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).
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.
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.
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.
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
The present invention includes a golf club head having a golf club face
with a plurality of grooves 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 grooves is to impart
a corrective spin on a struck 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.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1L are elevation views of the faces of a set of golf clubs
according to an embodiment of the present invention.
FIG. 2 is a schematic view illustrating the gear effect according to an
embodiment of the present invention.
FIG. 3 is a perspective view of a golfer illustrating different swing arcs
for different club heads.
FIG. 4 is an elevational view depicting decreasing shaft length as the loft
angle of club heads increases.
DETAILED DESCRIPTION
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.
Representative groove angles are shown in FIGS. 1A-1H, with reference to
the table 5 below.
TABLE
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
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.
1-1L, a number of additional clubs are shown having grooves of different
angles, as can be determined with reference to the TABLE. For the loft
wedge of FIG. 1L, a negative slope (meaning the lines angle in the
opposite direction) is shown.
The angular groove design imparts a corrective horizontal spin 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. 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 clubhead 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.
The angled grooves 16 run across the impact area 14 of the of the club face
from the sole 22 to the top edge 24 of the face 12. 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.
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.
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.
It should be appreciated that groove angles listed in the above table are
merely illustrative embodiments of the invention and are not intended to
limit the scope of the invention, except as to a specific embodiment. The
precise angles are not necessarily critical and deviations should also
produce acceptable results. To the contrary, 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. The deviations from the parameters listed
in the table 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. 1, 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.
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 continues. 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 to a golf ball, and other equivalent means may fall within
the inventive scope.
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