Golf ball dimple profile
The present invention concerns a golf ball having dimples with a cross-sectional profile comprising a conical top portion and a bottom portion. More particularly, the profiles of the present invention are defined by three independent parameters: dimple diameter (D D ), edge angle (Φ EDGE ), and saucer ratio (S r ). These parameters fully define the dimple shape and allow for greater flexibility in constructing a dimple profile versus conventional spherical dimples. The dimples optionally have a transition surface connecting the conical top portion to the land area of the golf ball and/or a transition surface connecting the conical top portion to the bottom portion.
1. A golf ball having a generally spherical surface and comprising a plurality of dimples separated by a land area formed on the ball surface, wherein at least a portion of the dimples are conical-protruding bottom dimples consisting of a top conical sidewall and a protruding bottom portion, wherein:
a first transition surface connects the top conical sidewall to the land area;
a secondary transition surface connects the top conical sidewall to the protruding bottom portion;
the protruding bottom portion consists of a protruding conical sidewall and a protruding spherical cap;
the conical-protruding bottom dimples have a protrusion bottom portion ratio, defined as the ratio of the protruding bottom portion diameter (D PB ) to the dimple diameter (D D ), of from about 0.05 to about 0.75; and
the conical-protruding bottom dimples have a protrusion saucer ratio, defined as the ratio of the protruding spherical cap diameter (D PS ) to the protruding bottom portion diameter (D PB ), of from about 0.05 to about 0.75.
2. The golf ball of claim 1 , wherein the secondary transition surface has a length L 2T and L 2T =D PS .
3. The golf ball of claim 1 , wherein the secondary transition surface has a length L 2T and L 2T <D PS .
4. The golf ball of claim 1 , wherein the secondary transition surface has a length L 2T and L 2T >D PS .
5. The golf ball of claim 1 , wherein the secondary transition surface has a length L 2T and L 2T =D D −D T , where D T is the diameter of the dimple at the point of intersection between the first transition surface and the top conical sidewall.
6. The golf ball of claim 1 , wherein the secondary transition surface has a length L 2T and L 2T <D D −D T , where D T is the diameter of the dimple at the point of intersection between the first transition surface and the top conical sidewall.
7. The golf ball of claim 1 , wherein the secondary transition surface has a length L 2T and L 2T >D D −D T , where D T is the diameter of the dimple at the point of intersection between the first transition surface and the top conical sidewall.
8. The golf ball of claim 1 , wherein the secondary transition surface has a length L 2T and L 2T =D PS =D D −D T , where D T is the diameter of the dimple at the point of intersection between the first transition surface and the top conical sidewall.
9. The golf ball of claim 1 , wherein the protruding bottom portion does not extend at any point beyond the phantom surface of the dimple.
10. The golf ball of claim 1 , wherein the protruding bottom portion does not extend at any point beyond the chord plane of the dimple.
11. The golf ball of claim 1 , wherein the conical-protruding bottom dimple has a protrusion angle θ P between the chord plane of the dimple and the protruding conical sidewall of from 10° to 30°.
12. The golf ball of claim 11 , wherein the difference between the edge angle θ EDGE of the dimple and the protrusion angle θ P of the dimple is 1° or less.
13. The golf ball of claim 11 , wherein the difference between the edge angle θ EDGE of the dimple and the protrusion angle θ P of the dimple is greater than 1°.
14. The golf ball of claim 1 , wherein the difference between the protrusion bottom portion ratio and the protrusion saucer ratio is 0.05 or less.
15. The golf ball of claim 1 , wherein the difference between the protrusion bottom portion ratio and the protrusion saucer ratio is greater than 0.05.
16. The golf ball of claim 1 , wherein the first transition surface is defined by a spherical arc rotated about a central axis.
17. The golf ball of claim 16 , wherein the secondary transition surface is defined by a spherical arc rotated about a central axis.
18. The golf ball of claim 17 , wherein the first transition surface and the secondary transition surface are opposite in concavity.
19. The golf ball of claim 1 , wherein the first transition surface is defined by a linear function rotated about a central axis.
20. The golf ball of claim 19 , wherein the secondary transition surface is defined by a spherical arc rotated about a central axis.