Iron type golf club head
View Patent ↗Iron-type golf club heads are disclosed having a heel portion, a sole portion, a toe portion, a top-line portion, a front portion, a rear portion, and a striking face. The iron-type golf club heads include a localized stiffened region that is located on the striking face of the club head such that the localized stiffened region alters the launch conditions of golf balls struck by the club head in a way that wholly or partially compensates for, overcomes, or prevents the occurrence of a rightward deviation. In particular, the localized stiffened region is located on the striking face such that a golf ball struck under typical conditions will not impart a right-tending sidespin to the golf ball.
1. A clubhead for an iron-type golf club comprising:
a heel,
a toe,
a sole,
a top-line, and
a striking face having a forward-facing ball-striking surface, a rearward-facing surface, and an ideal striking location;
wherein the striking face has a supported region and an unsupported region, with the ideal striking location lying within the unsupported region;
wherein a heel portion of the unsupported region of the striking face is located on a heel side of an imaginary center vertical plane that extends perpendicularly to the ground plane and that contains an imaginary line that extends in a direction normal to the striking face at the ideal striking location when the clubhead is in the normal address position, and wherein a toe portion of the unsupported region of the face is located on a toe side of the imaginary plane;
wherein the clubhead has a relative coefficient of restitution of at least −0.030; and wherein the following two inequalities are satisfied:
SA TOE >SA HEEL , (1)
and
[(Σ n=1 N E n t n 3 ׃( x,y ))÷ N ]÷[(Σ m=1 M E m t m 3 ׃( x,y ))÷ M]> 3.10 (2)
wherein:
SA TOE is the surface area of the ball-striking surface within the toe portion,
SA HEEL is the surface area of the ball-striking surface within the heel portion,
E n and t n are the effective Young's Modulus value and the thickness, respectively, for an nth cross-section of the toe portion of the unsupported region of the striking face,
E m and t m are the effective Young's Modulus value and the thickness, respectively, for an mth cross-section of the heel portion of the unsupported region of the striking face,
N and M hale values determined by discretizing SA TOE and SA HEEL , respectively, into 1 mm×1 mm sections; and
ƒ( x,y )= Ae −(a(x-x o ) 2 +2b(x-x 0 )(y-y 0 )+c(x-x 0 ) 2 )
wherein:
a two-dimensional x-y plane is defined to be tangent to the striking face and has an origin at the ideal striking location, with the x axis being parallel to the ground plane and having positive values extending toward the toe side, and the y axis being perpendicular to the x axis and having positive values extending toward the topline, and x is the x-coordinate and y is the y-coordinate for the center of an n th or m th cross-section:
a =(cos 2 θ÷2σ x 2 )+(sin 2 θ÷2σ y 2 );
b =(sin 2θ÷4σ x 2 )+(sin 2θ÷4σ y 2 ):
c =(sin 2 θ÷2σ x 2 )+(cos 2 θ÷2σ y 2 ):
A=1:
x 0 =7 mm:
y 0 =22 mm;
σ x =15 mm;
σ y =20 mm; and
Θ=30°.
2. The clubhead for an iron-type golf club of claim 1 having a relative coefficient of restitution of at least −0.025.
3. The clubhead for an iron-type golf club of claim 1 having a relative coefficient of restitution of at least −0.020.
4. The clubhead for an iron-type golf club of claim 1 having a relative coefficient of restitution of at least −0.010.
5. The clubhead for an iron-type golf club of claim 1 , wherein:
[
(
∑
n
=
1
N
E
n
t
n
3
×
f
(
x
,
y
)
)
÷
N
]
÷
[
(
∑
m
=
1
M
E
m
t
m
3
×
f
(
x
,
y
)
)
÷
M
]
>
4.0
.
6. The clubhead for an iron-type golf club of claim 1 , wherein:
[
(
∑
n
=
1
N
E
n
t
n
3
×
f
(
x
,
y
)
)
÷
N
]
÷
[
(
∑
m
=
1
M
E
m
t
m
3
×
f
(
x
,
y
)
)
÷
M
]
>
4.4
.