Hollow golf club head

• US 7,108,612 B2
• Filed: 08/15/2005
• Issued: 09/19/2006
• Est. Priority Date: 12/28/2001
• Status: Expired due to Fees

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Miyamoto, Masahiko, Mori, Tomoaki, Nakahara, Norihiko
• Primary Examiner(s): Passaniti, Sebastiano
• Application Number:
  US11/203,093
• Publication Number:
  US 20050272525A1
• Time in Patent Office: 400 Days
• Field of Search: 473/329, 473/324, 473/332, 473/345, 473/346, 473/347, 473/348, 473/349, 473/350
• US Class Current: 473/329
• CPC Class Codes: A63B 2209/00 Characteristics of used materials
• CPC Class Codes: A63B 2209/02 with reinforcing fibres, e.g. carbon, polyamide fibres
• CPC Class Codes: A63B 2209/023 Long, oriented fibres, e.g. wound filaments, woven fabrics, mats
• CPC Class Codes: A63B 53/0408 characterised by specific dimensions, e.g. thickness
• CPC Class Codes: A63B 53/0416 Heads having an impact surface provided by a face insert
• CPC Class Codes: A63B 53/0433 with special sole configurations
• CPC Class Codes: A63B 53/0437 with special crown configurations
• CPC Class Codes: A63B 53/045 Strengthening ribs
• CPC Class Codes: A63B 53/0454 Strengthening ribs on the rear surface of the impact face plate
• CPC Class Codes: A63B 53/0458 with non-uniform thickness of the impact face plate
• CPC Class Codes: A63B 53/0466 wood-type

Abstract

A hollow golf club head allowing to increase the repulsion and the degree of design freedom, while maintaining the durability. A hollow golf club head having a head body formed from a metal, wherein a hole is formed in the vicinity of the middle of a crown portion in the head body, the hole is closed with a cover member made of a material different from the head body, the ratio (ρm/ρf) of the specific gravity ρm of the head body and the specific gravity ρf of the cover member is set equal or superior to 1.3, and the ratio of the face area of a portion where the reinforcement and the head body are combined to the face area of the head body is set equal or superior to 20%.

Claims

1. A hollow golf club head comprising a hollow head body formed from a metal and having a hole formed in the vicinity of the middle of a crown portion and a hole formed in a vicinity of the middle of a sole portion of said head body, wherein each of the holes is closed with a cover member made of a material different from said head body, a ratio (ρ

m/ρ

f) of the specific gravity ρ

m of said head body and the specific gravity ρ

f of said cover member is set equal to or greater than 1.3, the face portion of the head body is laminated with a reinforcement made of a fiber reinforced plastic, and the ratio of the face area of a portion where said reinforcement and said head body are combined to the face area of said head body is set equal to or greater than 20%.

2. The hollow golf club head of claim 1, wherein said reinforcement is laminated inside the face portion of said head body.

3. The hollow golf club head of claim 1, wherein a material of the face portion of said head body is a titanium alloy, and the thickness of the titanium alloy of said face portion is equal to or less than 3.0mm.

4. The hollow golf club head of claim 1, wherein a material of the face portion of said head body is an iron alloy, and the thickness of the iron alloy of said face portion is equal to or less than 2.5 mm.

5. The hollow golf club head of claim 1, wherein a material of the face portion of said head body is an aluminum alloy, and the thickness of the aluminum alloy of said face portion is equal to or less than 4.0 mm.

6. The hollow golf club head of claim 1, wherein a coefficient of elasticity of a fiber of said fiber reinforced plastic is not more than 35 tons/mm².

7. The hollow golf club head of claim 1, wherein a total mass Wf of the cover member closing each hole is made lighter than the total mass Wx of the removed portion of said head body determined from the product of the virtual area of said hole, the virtual thickness of said hole and a specific gravity ρ

m of said head body.