U.S. patent application number 10/748670 was filed with the patent office on 2004-08-12 for iron-type golf club head with sole having stable static address position.
This patent application is currently assigned to Roger Cleveland Golf Co., Inc.. Invention is credited to Poincenot, Lionel, Roberts, Douglas E..
Application Number | 20040157679 10/748670 |
Document ID | / |
Family ID | 32829708 |
Filed Date | 2004-08-12 |
United States Patent
Application |
20040157679 |
Kind Code |
A1 |
Poincenot, Lionel ; et
al. |
August 12, 2004 |
Iron-type golf club head with sole having stable static address
position
Abstract
An iron-type golf club head having a sole, a center of gravity
CG, and a static contact point SCP on the sole substantially
vertically below the CG for providing stability when the club head
is in an address position, but the sole has no points lower than
the SCP when the club head is in the address position.
Additionally, the club head may have a centerline plane orthogonal
to the plane of the club face and containing the centerline of the
club face, with the center of gravity lying in the centerline plane
and the lowest point LP on the sole also lying substantially in the
centerline plane when the centerline plane is substantially
vertical, for minimizing mis-hits with the club head.
Inventors: |
Poincenot, Lionel;
(Carlsbad, CA) ; Roberts, Douglas E.; (La Palma,
CA) |
Correspondence
Address: |
PARKHURST & WENDEL, L.L.P.
1421 PRINCE STREET
SUITE 210
ALEXANDRIA
VA
22314-2805
US
|
Assignee: |
Roger Cleveland Golf Co.,
Inc.
Cypress
CA
|
Family ID: |
32829708 |
Appl. No.: |
10/748670 |
Filed: |
December 31, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60437047 |
Dec 31, 2002 |
|
|
|
Current U.S.
Class: |
473/324 ;
473/314 |
Current CPC
Class: |
A63B 53/0433 20200801;
A63B 53/047 20130101 |
Class at
Publication: |
473/324 ;
473/314 |
International
Class: |
A63B 053/04 |
Claims
What is claimed is:
1. An iron-type golf club head comprising a sole, a center of
gravity CG, and a static contact point SCP on said sole, said SCP
being substantially vertically below the CG when said club head is
in an address position, and said sole has no points lower than said
SCP when said club head is in the address position.
2. The golf club head of claim 1, wherein the SCP and at least one
other point substantially vertically below the CG define a static
contact line SCL.
3. The golf club head of claim 1, wherein the SCP and at least two
other points substantially vertically below the CG define a static
contact surface area SCA.
4. The golf club head of claim 3, wherein the static contact
surface area SCA is planar.
5. The golf club head of claim 3, wherein the static contact
surface area SCA is non-planar.
6. An iron-type golf club head, comprising a sole, a center of
gravity CG, and having a centerline plane orthogonal to the plane
of the club face and containing the centerline of the club face,
with the center of gravity lying in said centerline plane and the
lowest point LP on said sole also lying substantially in said
centerline plane when the centerline plane is substantially
vertical.
7. The golf club head of claim 6, wherein the sole additionally
comprises a lowest point surface area LPA which is comprised of
points substantially vertically below the center of gravity when
the centerline plane is vertical, and no points on the sole are
lower than said LP when the centerline plane is vertical.
8. The golf club head of claim 7, wherein the lowest point surface
area LPA is planar.
9. The golf club head of claim 7, wherein the lowest point surface
area LPA is non-planar.
10. The iron-type golf club head of claim 1, additionally having a
centerline plane orthogonal to the plane of the club face and
containing the centerline of the club face, with the center of
gravity lying in said centerline plane and the lowest point LP on
said sole also lying substantially in said centerline plane when
the centerline plane is substantially vertical.
11. The golf club head of claim 10, wherein the SCP and at least
one other point substantially vertically below the CG define a
static contact line SCL.
12. The golf club head of claim 10, wherein the SCP and at least
two other points substantially vertically below the CG define a
static contact surface area SCA.
13. The golf club head of claim 12, wherein the static contact
surface area SCA is planar.
14. The golf club head of claim 12, wherein the static contact
surface are SCA is non-planar.
15. The golf club head of claim 10, wherein the sole additionally
comprises a lowest point surface area LPA which is comprised of
points substantially vertically below the center of gravity when
the centerline plane is vertical, and no points on the sole are
lower than said LP when the centerline plane is vertical.
16. The golf club head of claim 15, wherein the lowest point
surface area LPA is planar.
17. The golf club head of claim 15, wherein the lowest point
surface area LPA is non-planar.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This U.S. utility patent application claims the benefit of
U.S. provisional patent application Serial No. 60/437,047, filed
Dec. 31, 2002, the entire disclosure of which is incorporated by
reference herein.
BACKGROUND
[0002] The present invention relates to the design of golf clubs,
and more particularly to designs to provide golf club heads of
iron-type golf clubs improved static stability when oriented in the
address position.
[0003] The address position of a golf club usually refers to the
orientation of the head of a golf club when a player is holding the
grip and shaft of the club in a substantially vertical plane with
the club head, attached to that shaft, being located just behind a
golf ball before hitting same, i.e., "addressing the ball," resting
on the ground just behind the golf ball. The sole of a golf club
head is the bottom surface(s) thereof, which may rest on the ground
when the club head is in an address position.
[0004] As discussed later herein, the sole portion of an iron-type
golf club often increases in total width (as measured in the club
face-to-back direction) at locations progressing from the heel
portion to the toe portion of the sole of the club head. The sole
of an iron-type golf club head may be substantially flat, or may be
curved from heel to toe (the so-called "radius" of the sole of a
club head) and/or curved from leading edge to trailing edge of the
sole (the so-called "camber" of the sole of a club head), such
curves causing the sole to bulge downwardly in a convex manner.
[0005] The "radius" of the sole of an iron type golf club is
preferably symmetrical with respect to the centerline plane of the
club head (which plane is discussed later herein). For example, the
earlier Hogan Radius irons, and Cleveland 792 VAS irons, are
examples of club heads having convex "radius" and "camber" sole
curvatures. Additionally, sand wedges often exhibit such sole
curvatures.
[0006] Iron-type golf club heads are ideally designed to strike a
ball with the face centerline, as shown in FIG. 1, in a centerline
plane perpendicular to both the hitting face of the club head, and
the ground. However, it is well known to those skilled in the art
that during a golf swing the shaft of a golf club bows outwardly
away from the body of the player swinging the club, causing the toe
of the club head to droop slightly. To compensate for such toe
droop at impact with the ball, the lie angle of a club head with a
given shaft should be chosen so that at impact with the ball the
centerline plane is perpendicular to both the hitting face and the
ground, as shown in FIG. 1. This lie angle of a club is said to be
"dynamically-proper." The "lie angle" of a club head is usually
said to be the angle, in a vertical plane, between the axis of the
hosel portion of the club head and a horizontal plane, measured
when the club head is oriented with its centerline plane in a
vertical position.
[0007] Herein the "address position" means a position wherein the
toe of a club head will be slightly raised, that is pivoted
upwardly about the heel, as schematically shown somewhat
exaggerated in FIG. 2. In other words, in the address position the
contact point of the club head with the ground, called the "static
contact point" SCP will be slightly heel-biased (located somewhat
toward the heel) from the aforementioned centerline plane. This is
in part due to the chosen "dynamically-proper" lie angle.
[0008] Many golf clubs, especially iron-type clubs, also exhibit
sole inversion or "bounce" to prevent the clubs from undesired
digging into the turf while hitting a golf ball. In a conventional
golf club the bounce angle of a club head in ball striking position
is the angle between a line (in the centerline plane, for example)
from the leading edge of the club face rearwardly toward the low
point of the sole of the club head and a horizontal line (in the
same plane), is generally between zero and twenty degrees, and
uniform along the entire length of the sole. A "bounce line" is
defined by the lowest points of the club head in a plurality of
planes perpendicular to the club face. This line is also the lowest
line in the face profile view of the club head. When in the address
position, a conventional club head is statically unstable, as shown
in FIG. 3, because the uniform bounce angle of the sole causes the
aforementioned heel-biased static contact point SCP of the club
head with the ground to be laterally (in the face-to-back
direction) offset a distance D with respect to a vertical line
through the center of gravity CG of the club head (i.e., at address
the ground contact point of a conventional golf club head is not
vertically below the center of gravity of the club head, but is on
a line vertically to the rear (or front) thereof, as viewed from
the heel looking toward the toe of the club head). Due to this
instability, the face of a conventional club head tends to open or
close at address, depending on whether the static ground contact
point is on a vertical line forward or rearward of the center of
gravity, as indicated in FIG. 3. A golf club having a propensity to
open or close at address does not feel balanced to the player, thus
undermining the player's confidence in the club. When a club is in
the address position, players expect it to feel steady, even when
applying only minimal grip pressure, and they also expect the club
head to look square to the desired initial line of ball flight.
[0009] Those skilled in the art will appreciate that when hitting a
golf ball, a golf club should make initial dynamic contact with the
ground at a low point LP on the sole, that lies substantially in
the centerline plane as discussed with respect to FIG. 1. This is
the low point of the usually symmetrical sole radius. If the club
head is not so designed, the accuracy of shots therewith may
suffer. For example, initial dynamic contact of the sole with the
ground toward the toe causes the club face to open, thereby
producing an undesired fade or slice shot. Similarly, initial
dynamic contact of the sole with the ground toward the heel causes
the club face to close, producing an undesired draw or hook shot.
As shown in FIG. 4, even if the lie angle of a conventional golf
club is "dynamically proper," the initial dynamic contact point of
the sole with the ground is typically still somewhat undesirably
toward the toe because the bounce angle is constant along the
entire length of the sole and the width of the sole increases from
heel to toe. FIG. 4 shows that the amount of sole surface exposed
in a face view of an iron-type club head is greater near the toe
portion of the sole (Distance B) than near the heel portion of the
sole of the club head (Distance A). Thus, on the downswing, the
sole of a conventional club typically will initially contact the
ground at a point along the bounce line somewhat toward the toe as
indicated in FIG. 5, causing the club face to open and an undesired
fade or slice shot to result.
[0010] The ground contact lowest point LP is located slightly
toward the toe a distance from the centerline plane of from about
0.050 inches to about 0.250 inches among clubs of a set of irons.
To eliminate such differences, the lie angle of the club head may
be adjusted by about 0.5 to about 1.5 degrees. This slight
adjustment in lie angle will cause the centerline plane to be
slightly out of perpendicular to a horizontal ground plane, which
can result in off-center ball strikes. However, the present
invention provides a solution to these problems.
BRIEF SUMMARY OF THE INVENTION
[0011] Hence, a need exists for an iron-type golf club that is
stable and feels steady at address, thus increasing the player's
confidence in that club. It is also desirable to provide a golf
club having a club head which will make initial dynamic contact
with the ground at the centerline plane junction with the sole, and
preferably vertically below the center of gravity of the club head,
thereby minimizing the possibility of club head-induced hook or
slice shots. The centerline plane can be maintained perpendicular
to the ground plane by modifying sole width, radius, camber and
bounce. Before such dynamic ball striking and ground contact,
steady address is achieved in the golf club head of the present
invention by providing in the sole of the club head a static
contact point, line and area preferably vertically below the center
of gravity of the club head when in an address position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Other advantages and further features of the advantageous
golf club head of the present invention are shown in and described
in conjunction with the following drawings:
[0013] FIG. 1 is a partially schematic face view of an iron-type
golf club head additionally illustrating certain aspects of the
present invention;
[0014] FIG. 2 is a schematic view of an iron-type golf club head
additionally schematically illustrating a status contact point when
the club head is at address position;
[0015] FIG. 3 is a partially schematic heel view of an iron-type
golf club head additionally illustrating certain aspects of the
present invention;
[0016] FIG. 4 is another face view like FIG. 1 but illustrating
further aspects of the present invention;
[0017] FIG. 5 is a partially schematic sole view of an iron-type
golf club head additionally illustrating still further aspects of
the present invention;
[0018] FIG. 6 is another sole view like FIG. 5, but illustrating
yet further aspects of the present invention; and
[0019] FIG. 7 is still another sole view like each of FIGS. 5 and
6, and illustrating even further aspects of the present
invention.
DETAILED DESCRIPTION
[0020] Referring to FIG. 6, consider an imaginary horizontal plane
(parallel to the ground plane) that is orthogonal to the plane
containing the face centerline, and which contains a point X which
is substantially on this centerline plane. The intersection of such
an imaginary plane with the sole surface of a club head, designated
Area 2, is a small area called the lowest point area LPA. For a
golf club initially to contact the ground at point X rather than at
a point LP on the downswing, any portion of the sole of the club
head lower than point X should be removed, such that point X and no
point lower than point X is the initial contact point of the club
head with the ground during ball striking. Removal of such lower
points may result in a lowest point area like LPA Area 2. While, as
initially identified above, LPA Area 2 is planar, it need not
necessarily be planar. And, while it is illustrated as elliptical
or circular, it need not have that perimeter shape. And, it could
be simply two or more points, a line or other surface area. Once
any excess material has been removed in forming LPA Area 2, as
generally described above, curvature, such as curvature similar to
the sole radius, may be imparted to that area as desired, so long
as no point in the LPA is lower than point X which remains the
initial contact point with the ground during ball striking with a
club having such a club head.
[0021] FIG. 7 illustrates the sole of the club head in address
position with the toe slightly elevated. An imaginary horizontal
plane that is parallel to the ground plane and which contains the
intersection point between the sole surface (Area 1) and the
vertical line passing through the center of gravity, intersects the
sole surface forming an Area 3. To minimize face to back offset
with respect to the center of gravity of the club head, of the
static point of contact SCP, and to prevent the club head from
undesirably opening or closing at address, any portion of the sole
of the club head lower than the static contact point SCP when the
club head is in an address position should be removed. Such
material is preferably removed so that the point of intersection
between a substantially vertical line passing through the center of
gravity and the sole surface is the static contact point SCP
between the club head and the ground plane when the club is in an
address position. Removal of such lower material may result in a
static contact surface area SCA like Area 3. If SCA Area 3 is
removed as described above, curvature also may be imparted thereto
as desired, so long as the point of intersection between the
vertical line passing through the center of gravity and the sole
surface remains the lowest static contact point SCP when the club
head is in an address position. While the static contact area SCA
is illustrated as elliptical in shape, it need not have that
perimeter shape, and it could be simply two or more points, a line
or other surface.
[0022] Thus, as indicated in FIGS. 6 and 7, LPA Area 2 and SCA Area
3 will have bounce angles different from those of the sole surface
Area 1. Those skilled in the art will appreciate that the bounce
angle specified for Area 2 may be between zero and about 20
degrees. The bounce angle of each of LPA Area 2 and SCA Area 3 may
vary with respect to the bounce angle specified for Area 1, by up
to about 5 degrees. It will also be appreciated that the present
invention may be facilitated by modifying sole width, sole radius,
and/or sole camber in addition to or in lieu of modifying bounce
angle. And, the specific topographies of each of LPA Area 2 and SCA
Area 3 may be achieved by using a number of different manufacturing
methods, including casting, machining, grinding, polishing, or any
other method of appropriately shaping those specific areas of a
club head.
* * * * *