Golf club heads are described comprising a striking surface that includes a center zone that is free of scorelines and an impact zone having an impact zone area, Aiz, and having a plurality of scorelines in the impact zone having an impact zone scoreline area, Asliz, such that a ratio Asliz/Aiz is at least 0.10.
1. A wood-type golf club head comprising:
a body having a crown, a sole, a heel, and a toe, the body defining an internal cavity having a front opening;
a striking plate attached to the body at the front opening, the striking plate comprising:
a composite face plate having a front surface, and
a cover layer attached to the front surface of the face plate, the cover layer defining a forward facing striking surface having a plurality of scorelines, each such scoreline having a scoreline depth of at least 0.1 mm,
a peripheral edge,
a center zone that is defined by an outer border constituting a center zone circle having a diameter Dcz, with the center of the center zone circle corresponding with a USGA center face location,
an impact zone that surrounds but does not include the center zone and that is defined by an outer border constituting a rectangle having its center at the USGA center face location and having upper and lower sides aligned parallel to an address position ground plane and heel and toe sides aligned perpendicular to the address position ground plane, with the upper and lower sides each having a length of 45 mm and the heel and toe sides each having a length of 30 mm, and with the impact zone having an impact zone area, Aiz, and
a peripheral zone that surrounds but does not include the impact zone and that extends to the peripheral edge, with the peripheral zone having a peripheral zone area, Apz;
wherein:
the club head defines a striking surface area of at least 4,000 mm 2 , and
the center zone circle diameter Dcz is between 1 mm to 10 mm,
wherein the portion of the cover layer within the center zone of the striking plate does not include any scorelines;
wherein the impact zone is provided with a plurality of scorelines having a scoreline area, Asliz, such that the ratio Asliz/Aiz is at least 0.17; and
wherein each of the scorelines outside the center zone extends across substantially the full width of the striking surface.
2. The golf club head of claim 1 , wherein the impact zone is provided with a plurality of scorelines having a scoreline area, Asliz, such that the ratio Asliz/Aiz is at least 0.20.
3. The golf club head of claim 1 , wherein the center zone circle diameter Dcz is between 3 mm to 8 mm.
4. The golf club head of claim 1 , wherein the center zone circle diameter Dcz is between 3 mm to 6 mm.
5. The golf club head of claim 1 , wherein the club head defines a striking surface area of at least 5,000 mm 2 .
6. The golf club head of claim 1 , wherein the peripheral zone is provided with a plurality of scorelines having a scoreline area, Aslpz, such that the ratio Aslpz/Apz is at least 0.10.
7. The golf club head of claim 1 , wherein the peripheral zone is provided with a plurality of scorelines having a scoreline area, Aslpz, such that the ratio Aslpz/Apz is at least 0.17.
8. The golf club head of claim 1 , wherein the peripheral zone is provided with a plurality of scorelines having a scoreline area, Aslpz, such that the ratio Aslpz/Apz is at least 0.20.
9. The golf club head of claim 1 , wherein the cover layer has an average thickness of between 0.2 mm to 0.75 mm throughout at least the center zone and impact zone, and the plurality of scorelines in the impact zone have an average depth that is between 0.1 mm and 0.4 mm.
10. The golf club head of claim 1 , wherein a ratio of the average depth of the plurality of scorelines in the impact zone to the average thickness of the cover layer in the impact zone is between 0.2 to 0.9.
11. The golf club head of claim 1 , wherein a ratio of the average depth of the plurality of scorelines in the impact zone to the average thickness of the cover layer in the impact zone is between 0.5 to 0.8.
12. The golf club head of claim 1 , wherein a ratio of the average depth of the plurality of scorelines in the impact zone to the average thickness of the cover layer in the impact zone is between 0.6 to 0.8.
13. The golf club head of claim 1 , wherein a volume of the golf club head is between 390 cc and 475 cc.
14. The golf club head of claim 1 , wherein a volume of the golf club head is greater than 400 cc.
15. The golf club head of claim 1 , wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5 for at least 50% of the scorelines in the impact zone.
16. The golf club head of claim 1 , wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5 for at least 75% of the scorelines in the impact zone.
17. The golf club head of claim 1 , wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:4 for at least 50% of the scorelines in the impact zone.
18. The golf club head of claim 1 , wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:4 for at least 75% of the scorelines in the impact zone.
19. The golf club head of claim 1 , wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5 for at least 50% of the scorelines in the peripheral zone.
20. A wood-type golf club head comprising:
a body having a crown, a sole, a heel, and a toe, the body defining an internal cavity having a front opening;
a striking plate attached to the body at the front opening, the striking plate comprising:
a composite face plate having a front surface, and
a cover layer attached to the front surface of the face plate, the cover layer defining a forward facing striking surface having a plurality of scorelines, each such scoreline having a scoreline depth of at least 0.1 mm,
a peripheral edge,
a center zone that is defined by an outer border constituting a center zone circle having a diameter Dcz, with the center of the center zone circle corresponding with a USGA center face location,
an impact zone that surrounds but does not include the center zone and that is defined by an outer border constituting a rectangle having its center at the USGA center face location and having upper and lower sides aligned parallel to an address position ground plane and heel and toe sides aligned perpendicular to the address position ground plane, with the upper and lower sides each having a length of 45 mm and the heel and toe sides each having a length of 30 mm, and with the impact zone having an impact zone area, Aiz, and
a peripheral zone that surrounds but does not include the impact zone and that extends to the peripheral edge, with the peripheral zone having a peripheral zone area, Apz;
wherein:
the club head defines a striking surface area of at least 4,000 mm 2 , and
the center zone circle diameter Dcz is between 1 mm to 10 mm,
wherein the portion of the cover layer within the center zone of the striking plate does not include any scorelines;
wherein the impact zone is provided with a plurality of scorelines having a scoreline area, Asliz, such that the ratio Asliz/Aiz is at least 0.17; and
wherein the scorelines additionally comprise a width of at least 0.6 mm, and a uniform scoreline spacing of less than 3 mm such that the impact zone comprises at least 10 scorelines.