Club head having balanced impact and swing performance characteristics
Described herein are embodiments of golf club heads having a balance of the following parameters: a low and back club head center of gravity position, a high moment of inertia, and low aerodynamic drag. Methods of manufacturing the embodiments of golf club heads having a balance of club head center of gravity position, moment of inertia, and aerodynamic drag are also described herein.
1. A hollow body golf club head comprising:
a body having a front end, a back end opposite the front end, a crown, a sole opposite the crown, a heel, a toe opposite the heel, a skirt adjoining the crown and the sole, and a hosel structure having a hosel axis extending centrally through a bore in the hosel structure;
a strikeface positioned at the front end and defining a geometric center, a loft plane tangent to the geometric center, and a head depth plane extending through the geometric center from the heel to the toe, perpendicular to the loft plane;
wherein:
a loft angle of the club head is between 12 degrees and 35 degrees;
a head center of gravity of the club head is located at a head CG depth from the loft plane, measured in a direction perpendicular to the loft plane, and at a head CG height from a head depth plane, measured in a direction perpendicular to the head depth plane;
the club head experiences a drag force F D when subjected to an air speed of 98 mph in a direction perpendicular to a plane extending through the geometric center of the strikeface, parallel to the hosel axis, and positioned at the loft angle from the loft plane;
the club head has a crown-to-sole moment of inertia I xx , a heel to toe
moment of inertia I yy , and a combined moment of inertia measured as the sum of the crown-to-sole moment of inertia and the heel to toe moment of inertia I xx +I yy ;
a rear radius of curvature that extends between the crown and the skirt of the club head along a rear transition boundary from a first rear transition point located at the junction between the crown and the rear transition boundary and a second rear transition point located at the junction between the rear transition boundary and the skirt of the club head;
a maximum crown height greater than 0.30 inch, wherein the maximum crown height is measured as the greatest distance between the surface of the crown and the crown axis; and
the club head satisfies relation A and one or more of relations B and C:
A
.
F
D
+
0.3
0.0002
(
I
xx
+
I
yy
)
<
1
B
.
F
D
<
1.0
lbf
C
.
I
xx
+
I
yy
>
5000
g
·
cm
2
.
2. The golf club head of claim 1 , wherein the club head further satisfies relation D:
D
.
F
D
+
0.4
0.0002
(
I
xx
+
I
yy
)
<
1.
3. The golf club head of claim 1 , wherein the head CG depth is greater than 1.0 inches and the head CG height is less than 0.20 inches.
4. The golf club head of claim 1 , further comprising one or more thin regions on the body having a thickness less than 0.02 inch.
5. The golf club head of claim 1 , further comprising:
a clock grid having at least:
a 12 o'clock ray;
a 3 o'clock ray;
a 4 o'clock ray;
a 5 o'clock ray;
a 8 o'clock ray; and
a 9 o'clock ray;
wherein:
the 12 o'clock ray is aligned with the geometric center of the strikeface and the clock grid is centered along the 12 o'clock ray at a midpoint between the front end and the back end of the club head;
the 3 o'clock ray extends towards the heel of the club head; and
the 9 o'clock ray extends towards the toe of the club head;
a weight structure located towards the sole and back end of the club head, the weight structure comprising a weight perimeter and a removable weight.
6. The golf club head of claim 5 , wherein the weight structure protrudes from an external contour of the sole.
7. The golf club head of claim 5 , wherein the weight structure comprises a removable weight having a weight center located between the 5 o'clock ray and the 8 o'clock ray of clock grid.
8. The golf club head of claim 1 , further comprises a crown angle less than 79 degrees, wherein the crown angle is measured as the acute angle between a front plane and a crown axis that extends through the crown transition point and the rear transition point of the club head.
9. The golf club head of claim 1 , further comprises a front radius of curvature between 0.18 to 0.30 inch, wherein the front radius of curvature extends from a top edge of the strikeface to a crown transition point, the crown transition point indicating a change in curvature from the front radius of curvature to a different curvature of the crown.
10. A hollow body golf club head comprising:
a body having a front end, a back end opposite the front end, a crown, a sole opposite the crown, a heel, a toe opposite the heel, a skirt adjoining the crown and the sole, and a hosel structure having a hosel axis extending centrally through a bore in the hosel structure;
a strikeface positioned at the front end and defining a geometric center, a loft plane tangent to the geometric center, and a head depth plane extending through the geometric center from the heel to the toe, perpendicular to the loft plane;
wherein:
a loft angle of the club head is between 12 degrees and 35 degrees;
a head center of gravity of the club head is located at a head CG depth from the loft plane, measured in a direction perpendicular to the loft plane, and at a head CG height from a head depth plane, measured in a direction perpendicular to the head depth plane;
the club head experiences a drag force F D when subjected to an air speed of 98 mph in a direction perpendicular to a plane extending through the geometric center of the strikeface, parallel to the hosel axis, and positioned at the loft angle from the loft plane
the club head has a crown-to-sole moment of inertia I xx , a heel to toe
moment of inertia I yy , and a combined moment of inertia measured as the sum of the crown-to-sole moment of inertia and the heel to toe moment of inertia I xx +I yy ;
a rear radius of curvature that extends between the crown and the skirt of the club head along a rear transition boundary from a first rear transition point located at the junction between the crown and the rear transition boundary and a second rear transition point located at the junction between the rear transition boundary and the skirt of the club head;
a maximum crown height greater than 0.30 inch, wherein the maximum crown height is measured as the greatest distance between the surface of the crown and the crown axis; and
the club head satisfies relation A and one or more of relations B and C:
A
.
F
D
+
1.65
2
(
head
CG
depth
)
<
1
B
.
F
D
<
1.0
lbf
C
.
head
CG
depth
>
1.0
inches
.
11. The golf club head of claim 10 , wherein the club head further satisfies relation D:
D
.
F
D
+
1.8
2
(
head
CG
depth
)
<
1.
12. The golf club head of claim 10 , wherein the combined moment of inertia is greater than 5000 g·cm 2 .
13. The golf club head of claim 10 , further comprising one or more thin regions on the body having a thickness less than 0.02 inch.
14. The golf club head of claim 10 , further comprising:
a clock grid having at least:
a 12 o'clock ray;
a 3 o'clock ray;
a 4 o'clock ray;
a 5 o'clock ray;
a 8 o'clock ray; and
a 9 o'clock ray;
wherein:
the 12 o'clock ray is aligned with the geometric center of the strikeface and the clock grid is centered along the 12 o'clock ray at a midpoint between the front end and the back end of the club head;
the 3 o'clock ray extends towards the heel of the club head; and
the 9 o'clock ray extends towards the toe of the club head;
a weight structure located towards the sole and back end of the club head, the weight structure comprising a weight perimeter and a removable weight.
15. The golf club head of claim 14 , wherein the weight structure protrudes from an external contour of the sole.
16. The golf club head of claim 14 , wherein the weight structure comprises a removable weight having a weight center located between the 5 o'clock ray and the 8 o'clock ray of clock grid.
17. The golf club head of claim 10 , further comprises a crown angle less than 79 degrees, wherein the crown angle is measured as the acute angle between a front plane and a crown axis that extends through the crown transition point and the rear transition point of the club head.
18. The golf club head of claim 10 , further comprises a front radius of curvature between 0.18 to 0.30 inch, wherein the front radius of curvature extends from a top edge of the strikeface to a crown transition point, the crown transition point indicating a change in curvature from the front radius of curvature to a different curvature of the crown.
19. The golf club head of claim 10 , wherein the combined moment of inertia is greater than 5,300 g·cm 2 .
20. The golf club head of claim 10 , wherein the combined moment of inertia is greater than 5,600 g·cm 2 .