# US 5,702,311 A · Multi-piece solid golf ball

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,702,311 A
- Document ID: US5702311A
- Status: Granted
- Kind: A
- Application number: 08/637,602
- Filed: 1996-04-25
- Granted: 1997-12-30
- Earliest claimed: 1995-05-12
- Assignees: Bridgestone Sports Co., Ltd.
- Inventors: Hiroshi Higuchi; Hisashi Yamagishi
- Web page: https://patentgrep.com/patent/US5702311A

## CPC

- A63B 37/0003: {Golf balls}
- A63B 37/0062: {Hardness}
- A63B 37/0031: {Hardness}
- A63B 37/0066: {Density; Specific gravity}
- A63B 37/0075: {Three piece balls, i.e. cover, intermediate layer and core}
- A63B 37/0076: {Multi-piece balls, i.e. having two or more intermediate layers}
- A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H)

## Abstract

In a multi-piece solid golf ball wherein a solid core of a multilayer structure including an innermost core and at least one intermediate layer enclosing the innermost core is surrounded by a cover, the golf ball has a specific gravity of 1.0-1.1 g/cm.sup.3 and a distortion A of 2.5-4.0 mm under a load of 100 kg, the innermost core has a distortion B of 3.0-6.0 mm under a load of 100 kg, wherein 1.2.ltoreq.B/A.ltoreq.1.7, and the cover has a greater hardness than the hardness of the innermost core. The ball will follow an appropriate high trajectory when hit by those golf players with a head speed of less than 40 m/sec. The ball is improved in flying performance, flying distance, feeling, impact, and durability.

## Claims

### Claim 1

A multi-piece solid golf ball comprising; a solid core of a multilayer structure including innermost core and at least one intermediate layer enclosing the innermost core, and a cover enclosing the solid core,
said golf ball having a specific gravity of 1.0 to 1.1, a weight of 40.8 to 44.9 g and a distortion of A mm under a load of 100 kg,
said innermost core having a distortion of B mm under a load of 100 kg, wherein B/A ranges from 1.2 to 1.7, and
said cover having a shore D hardness of at least 50 and a greater hardness than the hardness of the innermost core.

### Claim 2 (depends on 1)

The golf ball of claim 1 wherein said golf ball has a distortion A of 2.5 to 4.0 mm under a load of 100 kg and said innermost core has a distortion B of 3.0 to 6.0 mm under a load of 100 kg.

### Claim 3 (depends on 1)

The golf ball of claim 1 wherein said innermost core is formed of a rubber composition comprising a base rubber containing 1,4-polybutadiene having at least 40% of cis-structure, a crosslinking agent in the form of an organic peroxide, a co-crosslinking agent in the form of a metal salt of acrylic acid or methacrylic acid and a filler, said intermediate layer is formed of a rubber composition or a resin composition, said rubber composition comprising a base rubber containing 1,4-polybutadiene having at least 40% of cis-structure, a crosslinking agent in the form of an organic peroxide, a co-crosslinking agent in the form of a metal salt of acrylic acid or methacrylic acid and a filler, and said resin composition being based on an ionomer resin, said cover composition is formed of a composition based on an ionomer resin.

### Claim 4 (depends on 1)

The golf ball of claim 1 wherein said intermediate layer has a Shore D hardness in the range of 30 to 55.

### Claim 5 (depends on 1)

The golf ball of claim 1 wherein said intermediate layer has a diameter in the range of 25 to 35 mm.

### Claim 6 (depends on 1)

The golf ball of claim 1 wherein said innermost core has a weight in the range of 17.5 to 28.0 g.

### Claim 7 (depends on 1)

The golf ball of claim 1 wherein said cover has a Shore D hardness in the range of 60-70.

### Claim 8 (depends on 1)

The golf ball of claim 1 wherein said intermediate layer comprises inner and outer layers surrounding said innermost core.

### Claim 9 (depends on 8)

The golf ball of claim 8 wherein said innermost core has a weight in the range of 8.3 to 23.5 g.

### Claim 10 (depends on 8)

The golf ball of claim 8 wherein said inner layer has a Shore D hardness in the range of 55 to 75 and said outer intermediate layer has a Shore D hardness in the range of 30-55.

### Claim 11 (depends on 8)

The golf ball of claim 8 wherein said innermost core has a diameter in the range of 25 to 35 mm.

### Claim 12 (depends on 1)

The golf ball of claim 1 wherein said cover has a radial thickness in the range of 1.4 to 2.4 mm.

### Claim 13 (depends on 1)

The golf ball of claim 1 wherein said golf ball has a diameter in the range of 42.67 to 44.20 mm.

### Claim 14 (depends on 1)

The golf ball of claim 1 wherein said innermost core has a diameter in the range of 32 to 37 mm.