Variable density golf club

• US 20060035721A1
• Filed: 08/11/2004
• Published: 02/16/2006
• Est. Priority Date: 08/11/2004
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Bennett, Thomas O., Knutson, Scott A., Gilbert, Peter J.
• Granted Patent: US 7,815,523 B2
• Time in Patent Office: Days
• US Class Current: 473/335
• CPC Class Codes: A63B 2053/0491 with added weights, e.g. changeable, replaceable
• CPC Class Codes: A63B 53/047 iron-type
• CPC Class Codes: A63B 60/02 Ballast means for adjusting the centre of mass A63B60/24, A63B60/54 take precedence

Abstract

A golf club head having portions of varying density is disclosed and claimed. The club head includes a body with a recess in the back between the heel and toe and extending toward the sole. An insert that is configured to matingly correspond to the recess is positioned within the recess. The insert has a lower specific gravity than the club head body, biasing the club head mass toward the club head perimeter. The insert can form a muscle of the club head. The club head is forged, and the recess is formed by machining. After the insert is positioned within the recess, the club head-insert combination is subjected to additional forging and finishing steps. The present invention increases the club head moment of inertia and/or enlarges the club head sweet spot while retaining the golfer'"'"'s ability to work the golf ball and shape the golf shot. The present invention can be used with forged, blade, and muscle back clubs, which have not heretofore been enhanced in these manners.

Claims

1. A golf club head, comprising:

a body defining a front surface, a top line, a sole, a back, a heel, and a toe, said back containing a recess extending toward said sole, said body formed of a material having a first specific gravity; and

an insert positioned within said recess, said insert being configured to matingly correspond to said recess, said insert having a second specific gravity less than said first specific gravity.

2. The golf club head of claim 1, wherein said insert extends above said recess along said back to form a muscle of the club head.

3. The golf club head of claim 1, wherein said back is substantially free of any cavity.

4. The golf club head of claim 1, wherein said insert includes a lock groove to engage with said body to retain said insert within said recess.

5. The golf club head of claim 4, wherein said insert further includes a rib to impose a preload upon said body.

6. The golf club head of claim 4, wherein said insert is retained within said recess by swaging.

7. The golf club head of claim 1, wherein said first specific gravity is at least 8.

8. The golf club head of claim 1, wherein said second specific gravity is at most 8.

9. The golf club head of claim 8, wherein said first specific gravity is at least 8.

10. The golf club head of claim 1, wherein said second specific gravity is at most

11. The golf club head of claim 1, wherein a difference between said first and second specific gravities is at least 3.

12. The golf club head of claim 1, wherein said body is forged.

13. The golf club head of claim 1, wherein said insert is metallic.

14. The golf club head of claim 1, wherein said insert substantially fills said recess.

15. A golf club head, comprising a unitary body defining a front surface, a top line, a sole, a back, a heel, a toe, and a hosel, said body including a first material with a first specific gravity and a second material with a second specific gravity greater than said first specific gravity.

16. The golf club head of claim 15, wherein:

said first specific gravity is from 2.5 to 7; and

said second specific gravity is from 10 to 20.

17. The golf club head of claim 16, wherein:

said first specific gravity is from 3.5 to 5.5; and

said second specific gravity is from 15 to 20.

18. The golf club head of claim 15, wherein said second specific gravity is at least twice said first specific gravity.

19. The golf club head of claim 18, wherein said second specific gravity is at least three times said first specific gravity.

20. The golf club head of claim 15, wherein at least a portion of said toe includes said second material.

21. The golf club head of claim 15, wherein at least a portion of said hosel includes said second material.

22. The golf club head of claim 15, wherein at least a portion of said toe and at least a portion of said hosel includes said second material.

23. The golf club head of claim 15, wherein said back contains a recess extending toward said sole, and further comprising an insert positioned within said recess.

24. The golf club head of claim 23, wherein said insert has a third specific gravity less than said first and second specific gravities.

25. The golf club head of claim 23, wherein said third specific gravity is at most 8.

26. The golf club head of claim 25, wherein said third specific gravity is at most 5.

27. The golf club head of claim 23, wherein said insert is metallic.

28. A golf club head, comprising:

a body having a front surface, a top line, a sole, a back, a heel, a toe, and a hosel, said body including a first material with a first specific gravity;

a hosel insert including a second material with a second specific gravity; and

a toe insert including a third material with a third specific gravity.

29. The golf club head of claim 28, wherein said second and third specific gravities are greater than said fist specific gravity.

30. The golf club head of claim 29, wherein said second and third specific gravities are substantially equal.

31. The golf club head of claim 29, wherein said second specific gravity is greater than said third specific gravity.

32. The golf club head of claim 29, wherein said third specific gravity is greater than said second specific gravity.

33. The golf club head of claim 28, wherein:

said body includes titanium or a titanium alloy; and

said inserts include tungsten or a tungsten alloy.

34. The golf club head of claim 28, further including a center of gravity and wherein the club head has a moment of inertia as measured about a vertical axis passing through said center of gravity greater than 250 kg·

mm².

35. The golf club head of claim 34, wherein said moment of inertia is from 250 kg·

mm² to 300 kg·

mm².

36. The golf club head of claim 28, further including a center of gravity and wherein the club head has a moment of inertia as measured about a horizontal axis passing through said center of gravity greater than 55 kg·

mm².

37. The golf club head of claim 36, wherein said moment of inertia is from 55 kg·

mm² to 65 kg·

mm².

38. The golf club head of claim 28, wherein said hosel insert is a sleeve configured to overlie said hosel.

39. The golf club head of claim 38, wherein said sleeve is coupled to said hosel by press fit, bonding, or brazing.

40. The golf club head of claim 28, wherein:

said body includes a recess therein; and

said toe insert is configured to fit within said recess.

41. The golf club head of claim 40, wherein said toe insert is configured to substantially fill said recess.

42-43. -43. (canceled)