Golf club head
Golf club heads including a striking face with a variable thickness, a shell including a crown, and an internal weight pad located on a lower portion of the shell. The center of gravity depths of at least two golf club heads in a set satisfy the equation: D=a−b*LA, with 19 mm<a<22 mm and b=0.36 mm/degrees, and the at least two golf club heads have a difference in loft angle LA of at least 5 degrees. A moment of inertia about a vertical axis through the center of gravity of each of the at least two golf club heads is at least 2900 g*cm 2 . In one aspect, a striking face has a center region having a first thickness T1, an intermediate region having a second thickness T2, and a perimeter region having a third thickness T3, with T2<T1<T3.
1. A set of iron-type golf clubs, comprising:
at least two golf clubs each including a golf club head that, when oriented in a reference position, comprises:
a striking face comprising a face center and a variable thickness such that the striking face has a perimeter region proximate an outer boundary of the striking face and a maximum thickness of the striking face is located in the perimeter region;
a shell including a crown, a sole opposite the crown, a heel, a toe, and an internal weight pad located on a lower portion of the shell;
a loft angle LA of at least 20 degrees; and
a center of gravity having a center of gravity depth D, wherein the center of gravity depths of the at least two of the golf club heads satisfy the equation:
19 mm-0.36 mm/degrees* LA<D< 22 mm-0.36 mm/degrees* LA,
wherein the at least two golf club heads have a difference in loft angle LA of at least 5 degrees, and
wherein a moment of inertia about a vertical axis through the center of gravity of each of the at least two golf club heads is at least 2900 g*cm 2 .
2. The set of iron-type golf clubs of claim 1 , wherein the weight pad and the shell comprise a unitary investment casted component.
3. The set of iron-type golf clubs of claim 1 , wherein the weight pad is entirely spaced apart from the striking face.
4. The set of iron-type golf clubs of claim 1 , wherein the striking face comprises a face insert.
5. The set of iron-type golf clubs of claim 4 , wherein the face insert comprises a material different from the shell.
6. The set of iron-type golf clubs of claim 1 , wherein a moment of inertia about a horizontal axis substantially parallel to the striking face through the center of gravity of the at least two golf club heads is at least 900 g*cm2.
7. The set of iron-type golf clubs of claim 1 , wherein the weight pad of the higher lofted head of the at least two golf club heads has a first center of gravity located toe-ward of the center of gravity of the head center of gravity and the weight pad of the lower lofted head of the at least two golf club heads has a second center of gravity that is more toe-ward than the first center of gravity.
8. The set of iron-type golf clubs of claim 1 , wherein the weight pad comprises a weight port and the at least two golf club heads each include a removable weight received in the weight port.
9. The set of iron-type golf clubs of claim 1 , wherein the center of gravity depths of at least two of the golf club heads satisfy the equation: D=a−b*L, with 20 mm<a<21 mm and b=0.36 mm/degrees.
10. The set of iron-type golf clubs of claim 1 , wherein the striking face comprises a center region having a first thickness T1, an intermediate region having a second thickness T2 surrounding the center region, and a perimeter region surrounding the intermediate region having a third thickness T3, and wherein T2<T1<T3.
11. The set of iron-type golf clubs of claim 10 , wherein the striking face of the at least two golf clubs have substantially the same variable thickness pattern.
12. The set of iron-type golf clubs of claim 1 , wherein the golf club head has a weighted COR of at least 0.70, the weighted COR being determined based on the following relationship:
Weighted COR=Σ i=1 n Σ j=1 m p ij *c ij ,
wherein:
(a) a rectangular virtual evaluation region is superimposed onto the striking face, the rectangular virtual evaluation region comprising a first pair of horizontal sides having a length of 35 mm, a second pair of vertical sides having a length of 25 mm, and a geometric center that coincides with the face center;
(b) the rectangular virtual evaluation region is divided into 5 rows (m) having an equal height of 5 mm and is divided into 7 columns (n) having an equal width of 5 mm, thereby forming a matrix of bins having coordinates i and j;
(c) c ij corresponds to an average COR value associated with bin i, j;
(d) p ij corresponds to a bin-specific impact probability value in accordance with the following:
i = 1
i = 2
i = 3
i = 4
i = 5
i = 6
i = 7
j = 1
0.42%
0.43%
0.30%
0.22%
0.11%
0.03%
0.03%
j = 2
3.58%
3.64%
2.96%
2.23%
1.20%
0.76%
0.31%
j = 3
5.46%
8.29%
8.54%
6.50%
4.42%
2.43%
1.06%
j = 4
3.36%
5.97%
6.55%
6.65%
5.01%
2.83%
1.19%
j = 5
1.52%
2.43%
3.31%
3.18%
2.49%
1.80%
0.81%
13. An iron type golf club head that, when oriented in a reference position, comprises:
a striking face comprising a face center and a variable thickness with a center region having a first thickness T1, an intermediate region having a second thickness T2 surrounding the center region, and a perimeter region surrounding the intermediate region having a third thickness T3, and wherein T2<T1<T3;
a shell including crown, a sole opposite the crown, a heel, a toe, and an internal weight pad located on a lower portion of the shell;
a loft angle LA of at least 20 degrees; and
a center of gravity having a center of gravity depth D that satisfies the equation:
19 mm-0.36 mm/degrees* LA<D< 22 mm-0.36 mm/degrees* LA,
wherein a moment of inertia about a vertical axis through the center of gravity of each of the at least two golf club heads is at least 2900 g*cm 2 .
14. The iron-type golf club head of claim 13 , wherein the weight pad and the shell comprise a unitary investment casted component.
15. The iron-type golf club head of claim 13 , wherein the weight pad is entirely spaced apart from the striking face.
16. The iron-type golf club head of claim 13 , wherein the striking face comprises a face insert.
17. The iron-type golf club head of claim 13 , wherein the weight pad comprises a U shape.
18. The iron-type golf club head of claim 13 , wherein the weight pad is located substantially toe-ward of the head center of gravity.