# US 4,340,226 A · Games racket

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- Number: US 4,340,226 A
- Document ID: US4340226A
- Status: Granted
- Kind: A
- Application number: 06/177,394
- Filed: 1980-08-12
- Granted: 1982-07-20
- Earliest claimed: 1979-08-24
- Assignees: Dunlop Limited
- Inventors: Robert C. Haines
- Web page: https://patentgrep.com/patent/US4340226A

## CPC

- A63B 49/10: made of non-metallic materials, other than wood
- A63B 60/00: Details or accessories of golf clubs, bats, rackets or the like
- A63B 60/08: characterised by the material
- A63B 2049/0212: {with defined weight}
- A63B 2049/103: {string holes produced during moulding process}
- Y10S 273/08: Urethane
- A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A hollow injection moulded thermoplastics games racket frame comprising a head (21) and a shaft (20), the head (21) having integrally-formed internal supports (25) containing the stringing holes (23) and the moulding being polyurethane foam-filled. The foam filling is provided in two parts, a lighter filling (32) for the head and a denser filling (33) for the shaft. The shaft filling (33) is integrally-formed with a foam handle portion (34). The handle end of the shaft is preferably provided with moulded-in holes (31) through which filling (33) can flow during its foaming.

## Claims

### Claim 1

A games racket comprising:
A head and a shaft, the head being of hollow tubular cross section over a majority of its perimeter, the shaft having a hollow tubular cross section in communication with the hollow tubular cross section of the head so that both said hollow tubular cross sections may be filled with foam material injected from the distal end of said shaft,
a first foam material of polyurethane foam of density from 0.10 to 0.25 g/c.c., filling at least the hollow cross section of said head,
a second foam material of rigid polyurethane foam of density from 0.30 to 0.50 g/c.c., filling the entire remaining hollow portion of said shaft from an interface with said first foam, said second foam material also covering the outer surface of the shaft adjacent the distal end thereof so as to form a handle thereon of a larger diameter than said shaft which is integral with the second foam material inside said hollow cross section of said shaft.

### Claim 2 (depends on 1)

A games racket frame according to claim 1 in which said filling of the head is of rigid foam.

### Claim 3 (depends on 2)

A games racket frame according to claim 2, in which said head filling and said shaft filling are of substantially the same polyurethane foam formulation.

### Claim 4 (depends on 1, 2, 3)

A games racket frame according to claim 1, 2 or 3, in which said polyurethane foam is a reaction product of a polyol with methylene diisocyanate or tolylene diisocyanate.

### Claim 5 (depends on 1, 2, 3)

A games racket frame according to claim 1, 2 or 3, in which the foam used for said head filling has a free-rise density of 0.03 to 0.04 g/c.c.

### Claim 6 (depends on 1, 2, 3)

A games racket frame according to claim 1, 2 or 3, in which the foam used for said shaft filling has a free-rise density of 0.20 to 0.22 g/c.c.

### Claim 7 (depends on 1, 2, 3)

A games racket frame according to claim 1, 2 or 3, in which said handle portion of the shaft has holes through which the shaft foam filling can flow during its foaming.

### Claim 8 (depends on 7)

A games racket frame according to claim 7, in which said holes are integrally moulded in the shaft of the frame.

### Claim 9 (depends on 1, 2, 3, 8)

A games racket frame according to any one of claims 1, 2, 3 or 8, in which said internal support means is a row of centrally-disposed pillars, the row extending around the head portion of the frame.

### Claim 10 (depends on 7, 8)

A games racket frame according to claim 7 or 8, in which said handle is integrally-formed with the shaft through the holes in the shaft.

### Claim 11 (depends on 1)

A games racket frame according to claim 1, in which said handle is also integrally-formed with the shaft by surrounding the distal end thereof.

### Claim 12 (depends on 1)

A games racket frame according to claim 1, in which said handle is integrally-formed with the shaft by surrounding the distal end thereof.

### Claim 13 (depends on 1)

A games racket frame according to claim 1, in which said head has stringing holes, the wall of said head which lies at the outer perimeter of said head is joined to the wall which lies at the inner perimeter of said head by an internal support means, and said stringing holes pass through said support means, and said walls and support means of the head are integrally-formed.