Golf ball dimple plan shape
The present invention is directed to golf balls having improved aerodynamic performance due, at least in part, to the selection of the plan shapes of the dimples thereon. In particular, the present invention is directed to a golf ball that includes at least a portion of its dimples having a plan shape defined by low frequency periodic functions along a closed simple path. In addition, the present invention provides methods for designing dimples having a plan shape defined by a low frequency periodic function along a closed simple path.
1. A golf ball having a generally spherical surface and comprising a plurality of dimples on the spherical surface, wherein at least a portion of the plurality of dimples have a non-circular plan shape defined by a low frequency periodic sawtooth function mapped along a circular simple closed path resulting in the following function:
Q ( x )= F path ( l,scl,x )* F periodic ( s,a,p,x )
where F path is a circular function of length l, with scale factor scl, defined along the vertices x;
and F periodic is a periodic sawtooth function defined by the equation:
f
(
x
)
=
s
-
a
π
(
sin
(
π
px
)
+
1
2
sin
(
2
π
px
)
+
1
3
sin
(
3
π
px
)
+
1
4
sin
(
4
π
px
)
)
,
with sharpness factor s, amplitude a, and period p defined at the vertices x, and wherein period p is about 15 or less and amplitude a is about 1 or less.
2. The golf ball of claim 1 , wherein at least a portion comprises about 50 percent or more of the dimples on the golf ball.
3. The golf ball of claim 1 , wherein at least a portion comprises about 80 percent or more of the dimples on the golf ball.
4. The golf ball of claim 1 , wherein the low frequency periodic sawtooth function has a period of about 10 or less.
5. The golf ball of claim 1 , wherein the low frequency periodic sawtooth function has a period of about 8 or less.
6. The golf ball of claim 1 , wherein the low frequency periodic sawtooth function has a period of about 5 or less.
7. The golf ball of claim 1 , wherein the plan shape has an amplitude, A, of less than about 0.500 inches.
8. The golf ball of claim 1 , wherein the circular path has a radius of from about 0.025 inches to about 0.150 inches.
9. The golf ball of claim 8 , wherein the maximum distance at any point on the plan shape from the circular path is from about 0.001 inches to about 0.015 inches.
10. The golf ball of claim 8 , wherein the maximum distance at any point on the plan shape from the circular path is from about 0.002 inches to about 0.008 inches.
11. The golf ball of claim 1 , wherein the plan shape has an amplitude A of about 0.0005 inches to about 0.1000 inches.