GB2089219A - Wooden racket frames - Google Patents

Wooden racket frames Download PDF

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Publication number
GB2089219A
GB2089219A GB8136251A GB8136251A GB2089219A GB 2089219 A GB2089219 A GB 2089219A GB 8136251 A GB8136251 A GB 8136251A GB 8136251 A GB8136251 A GB 8136251A GB 2089219 A GB2089219 A GB 2089219A
Authority
GB
United Kingdom
Prior art keywords
frame
throat
wooden
piece
plastics material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8136251A
Other versions
GB2089219B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dunlop Ltd
Original Assignee
Dunlop Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dunlop Ltd filed Critical Dunlop Ltd
Priority to GB8136251A priority Critical patent/GB2089219B/en
Publication of GB2089219A publication Critical patent/GB2089219A/en
Application granted granted Critical
Publication of GB2089219B publication Critical patent/GB2089219B/en
Expired legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A63—SPORTS; GAMES; AMUSEMENTS
    • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
    • A63B49/00—Stringed rackets, e.g. for tennis
    • A63B49/02—Frames
    • A63B49/03—Frames characterised by throat sections, i.e. sections or elements between the head and the shaft

Landscapes

  • Health & Medical Sciences (AREA)
  • Pulmonology (AREA)
  • General Health & Medical Sciences (AREA)
  • Physical Education & Sports Medicine (AREA)
  • Laminated Bodies (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)

Abstract

A wooden racket frame comprises a head-portion (10), a handle-portion (11) integrally formed therewith, reinforcing members (12,13,14) and a throat-piece (15). At least the throat- piece (15) is made of a cellular plastics material, which may comprise a polyurethane foam or a polymethacrylimide foam. The use of a plastics material for the throat-piece results in an overall decrease in weight of up to 12 g when compared with an "all-wood" frame. <IMAGE>

Description

SPECIFICATION Wooden racket frames This invention relates to wooden racket frames.
Whilst the present invention will be described herein with particular reference to wooden racket frames comprising a head portion and a handle portion integrally formed therewith, it is not to be construed as being limited thereto.
Wooden racket frames are conventionally made by laying-up a plurality of laminae of one or more woods (e.g. ash, beech and maple), applying an adhesive to the adjacent surfaces of the laminae, forming the assembly into a "keyhole" configuration with the aid of additional wooden components including a throat piece and applying pressure thereto to form an integral structure.
Subsequently, other wooden components are bonded to the structure to complete the frame, such inserts including handle-reinforcements and framereinforcements. The frame may then be further strengthened by the application of reinforcing laminae which are bonded to the frame by means of thermosettable adhesives.
With the recent increase in popularity of games involving the use of wooden-framed rackets (especially tennis and squash) the supply of suitable woods of sufficiently low density has decreased, whilst the demand for lighter-weight frames has increased.
We have found that the weight of a wooden racket frame may be considerably reduced, without adverse effect on the physical dynamic and playing properties of the rackets, if the conventional wooden throat-piece is replaced by a throat-piece made of a cellular plastics material.
Accordingly, the present invention provides a wooden racket frame comprising a head-portion and a handle-portion integrally formed therewith, together with a throat-piece and other reinforcing members, in which at least the throat-piece is made of a cellular plastics material.
The cellular plastics material should have a density of less than 350 Kg/m3, a Young's Modulus in the range 30 to 110 N/mm2 (preferably about 70 N/mm2) and a flexural strength in the range 0.5 to 2.7 N/mm2 (preferably about 1.6 N/mm2).
Suitable cellular plastics material include polyurethane foams and polymethacrylimide foams.
The present invention will be illustrated, merely by way of example, in the following description and with reference to the accompanying drawing.
The drawing shows schematically a side elevation of a racket frame comprising a head-portion 10, a handle-portion 11, reinforcing members for the head-portion (12, 13 and 14 respectively) and a throat-piece 15.
Example 1 A polyurethane foam having a free-height density of 200 to 220 Kg/m3 was moulded to a shape suitable for use as a throat-piece and bonded into position in a wooden tennis racket frame. The frame was subsequently faced with five laminae 0.8 mm thick of vulcanised fibre in the region between X and Z on each side of the frame. The frame was about 6 g lighter than a comparable frame with a mahogany throat-piece. The durability and impact-resistance was acceptable, as was the performance of the frame in play.
Example 2 A polymethacrylimide foam, available from Roehm GmbH as ROHACELL 51 was machined to a shape suitable for use as a throat-piece and bonded in position in a wooden tennis racket frame. The frame was subsequently faced with glass-fibrereinforced laminae 0.4 mm thick in the region between X and Z on each side of the frame and further laminae 0.8 mm thick in the region between X and Y on each side of the frame.
The throat-piece of ROHACELL 51 weighed approximately 1.65 g (compared to one of mahogany which weighed about 13 g). The overall reduction in weight for the racket when compared with an "all-wood" racket was lotto 12 g.
1. Awooden racket frame comprising a head portion and a handle-portion integrally formed therewith, together with a throat-piece and one or more reinforcing members, in which at least the throat-piece is made of a cellular plastics material.
2. A frame according to Claim 1, in which the cellular plastics material has a density of less than 350 kg/m3.
3. A frame according to Claim 1 or 2, in which the cellular plastics material has a Young's Modulus in the range 30 to 110 N/mm2.
4. A frame according to Claim 3, in which the cellular plastics material has Young's Modulus of 70 N/mm2.
5. A frame according to any one of Claims 1 to 4, in which the cellular plastics material has a flexural strength in the range 0.5 to 2.7 N/mm2.
6. Aframe according to Claim 5, in which the cellular plastics material has a flexural strength of 1.6 N/mm2.
7. Aframe according to any of Claims 1 to 6, in which the cellular plastics material comprises a polyurethane foam.
8. A frame according to any one of Claims 1 to 6, in which the cellular plastics material comprises a polymethacrylimide foam.
9. Awooden racket frame, substantially as hereinbefore described with reference to either of the Examples.
10. A racket having a wooden frame according to any one of the preceding claims.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Wooden racket frames This invention relates to wooden racket frames. Whilst the present invention will be described herein with particular reference to wooden racket frames comprising a head portion and a handle portion integrally formed therewith, it is not to be construed as being limited thereto. Wooden racket frames are conventionally made by laying-up a plurality of laminae of one or more woods (e.g. ash, beech and maple), applying an adhesive to the adjacent surfaces of the laminae, forming the assembly into a "keyhole" configuration with the aid of additional wooden components including a throat piece and applying pressure thereto to form an integral structure. Subsequently, other wooden components are bonded to the structure to complete the frame, such inserts including handle-reinforcements and framereinforcements. The frame may then be further strengthened by the application of reinforcing laminae which are bonded to the frame by means of thermosettable adhesives. With the recent increase in popularity of games involving the use of wooden-framed rackets (especially tennis and squash) the supply of suitable woods of sufficiently low density has decreased, whilst the demand for lighter-weight frames has increased. We have found that the weight of a wooden racket frame may be considerably reduced, without adverse effect on the physical dynamic and playing properties of the rackets, if the conventional wooden throat-piece is replaced by a throat-piece made of a cellular plastics material. Accordingly, the present invention provides a wooden racket frame comprising a head-portion and a handle-portion integrally formed therewith, together with a throat-piece and other reinforcing members, in which at least the throat-piece is made of a cellular plastics material. The cellular plastics material should have a density of less than 350 Kg/m3, a Young's Modulus in the range 30 to 110 N/mm2 (preferably about 70 N/mm2) and a flexural strength in the range 0.5 to 2.7 N/mm2 (preferably about 1.6 N/mm2). Suitable cellular plastics material include polyurethane foams and polymethacrylimide foams. The present invention will be illustrated, merely by way of example, in the following description and with reference to the accompanying drawing. The drawing shows schematically a side elevation of a racket frame comprising a head-portion 10, a handle-portion 11, reinforcing members for the head-portion (12, 13 and 14 respectively) and a throat-piece 15. Example 1 A polyurethane foam having a free-height density of 200 to 220 Kg/m3 was moulded to a shape suitable for use as a throat-piece and bonded into position in a wooden tennis racket frame. The frame was subsequently faced with five laminae 0.8 mm thick of vulcanised fibre in the region between X and Z on each side of the frame. The frame was about 6 g lighter than a comparable frame with a mahogany throat-piece. The durability and impact-resistance was acceptable, as was the performance of the frame in play. Example 2 A polymethacrylimide foam, available from Roehm GmbH as ROHACELL 51 was machined to a shape suitable for use as a throat-piece and bonded in position in a wooden tennis racket frame. The frame was subsequently faced with glass-fibrereinforced laminae 0.4 mm thick in the region between X and Z on each side of the frame and further laminae 0.8 mm thick in the region between X and Y on each side of the frame. The throat-piece of ROHACELL 51 weighed approximately 1.65 g (compared to one of mahogany which weighed about 13 g). The overall reduction in weight for the racket when compared with an "all-wood" racket was lotto 12 g. CLAIMS
1. Awooden racket frame comprising a head portion and a handle-portion integrally formed therewith, together with a throat-piece and one or more reinforcing members, in which at least the throat-piece is made of a cellular plastics material.
2. A frame according to Claim 1, in which the cellular plastics material has a density of less than 350 kg/m3.
3. A frame according to Claim 1 or 2, in which the cellular plastics material has a Young's Modulus in the range 30 to 110 N/mm2.
4. A frame according to Claim 3, in which the cellular plastics material has Young's Modulus of 70 N/mm2.
5. A frame according to any one of Claims 1 to 4, in which the cellular plastics material has a flexural strength in the range 0.5 to 2.7 N/mm2.
6. Aframe according to Claim 5, in which the cellular plastics material has a flexural strength of 1.6 N/mm2.
7. Aframe according to any of Claims 1 to 6, in which the cellular plastics material comprises a polyurethane foam.
8. A frame according to any one of Claims 1 to 6, in which the cellular plastics material comprises a polymethacrylimide foam.
9. Awooden racket frame, substantially as hereinbefore described with reference to either of the Examples.
10. A racket having a wooden frame according to any one of the preceding claims.
GB8136251A 1980-12-12 1981-12-01 Wooden racket frames Expired GB2089219B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8136251A GB2089219B (en) 1980-12-12 1981-12-01 Wooden racket frames

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8039957 1980-12-12
GB8136251A GB2089219B (en) 1980-12-12 1981-12-01 Wooden racket frames

Publications (2)

Publication Number Publication Date
GB2089219A true GB2089219A (en) 1982-06-23
GB2089219B GB2089219B (en) 1984-05-23

Family

ID=26277831

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8136251A Expired GB2089219B (en) 1980-12-12 1981-12-01 Wooden racket frames

Country Status (1)

Country Link
GB (1) GB2089219B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5217223A (en) * 1991-07-11 1993-06-08 Lisco, Inc. Tennis racket with metal/composite frame
WO1994013365A1 (en) * 1992-12-10 1994-06-23 Prince Sports Group, Inc. Monoshaft composite tennis racquet

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5217223A (en) * 1991-07-11 1993-06-08 Lisco, Inc. Tennis racket with metal/composite frame
WO1994013365A1 (en) * 1992-12-10 1994-06-23 Prince Sports Group, Inc. Monoshaft composite tennis racquet

Also Published As

Publication number Publication date
GB2089219B (en) 1984-05-23

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)