Games using tangible projectile – Player held and powered – nonmechanical projector – per se,... – Racket or paddle; accessory therefor
Reexamination Certificate
1999-12-03
2001-10-16
Chiu, Raleigh W. (Department: 3711)
Games using tangible projectile
Player held and powered, nonmechanical projector, per se,...
Racket or paddle; accessory therefor
Reexamination Certificate
active
06302812
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a games racket frame, more particularly, but not exclusively, a racket frame for use in tennis, squash or badminton.
Rackets for the games of tennis, squash and badminton need to be stiff, strong and light. Better quality racket frames are now made from composite materials composed of fibres of carbon, glass or aramid (or combinations of these) in a matrix of a thermosetting resin, usually epoxy resin. The fibres are usually in continuous form and are made into sheet material for subsequent processing, either by weaving into a fabric which is then coated with resin or alternatively by assembling the fibres in parallel where they are located together by the adhesive qualities of the resin coating subsequently applied.
Rackets constructed in the above way are generally satisfactory except as regards vibration damping. That is, vibrations occurring in the racket upon impact with a ball or shuttlecock are insufficiently damped, resulting in a shock to the hand and arm of the player.
Consequently, there is a need for a games racket frame having improved vibration damping characteristics.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a games racket frame, comprising: a main frame in the form of a hollow tubular structure made of a fibre reinforced composite including a thermosetting material; and at least one additional component including a thermoplastic material and integrated with the main frame in order to change the vibration characteristics of the main frame.
Preferably, the additional component is fitted around the hollow tubular structure of the main frame; this can be achieved by providing at least one internal through hole through which the main frame is inserted.
Preferably also, the main frame is a modulated frame and the additional component is consolidated into the main frame during the moulding process.
Embodiments of the invention include: (i) two additional components, one at each of two corresponding points on either side of the racket frame; (ii) an additional component forming the bridge of the racket frame, so as to join together two portions of the main frame; and (iii) an additional component provided at a shaft of the main frame, passing around two parallel portions of the hollow tubular structure. Any combination of these embodiments is possible.
In the case of (i), each additional component is preferably a hollow cylinder, the axis of which is curved to fit the tubular structure at the part of the head where it is positioned. In the case of (ii), the additional component preferably comprises two legs each of similar form as in (i) and joined by an integrally-formed cross-piece. In the case of (iii), preferably the additional component comprises a body passing around both portions of the tubular structure, and two legs extending from the body along respective single portions of the tubular structure.
For the materials of the main frame and additional component(s), a composite of carbon fibre and epoxy resin is preferably used for the main frame, and for the additional component, nylon, polypropylene or polyurethane may be used, with or without reinforcing fibre.
According to another aspect of the present invention, there is provided a method of manufacturing a games racket frame, comprising the steps of: making a main frame by forming a hollow tubular structure from a composite including a thermosetting material; making at least one additional component including a thermoplastic material; and integrating the or each additional component with the main frame, thereby changing the vibration characteristics of the main frame.
In this method, preferably, the main frame is made by applying the thermosetting material to impregnate the fibrous material, wrapping layers of a fibrous material around a mandrel, so that adjacent layers adhere together, removing the mandrel, and then bending the hollow tubular structure into a desired shape;
the or each additional component is made by injection moulding or the thermoplastic material; and
the or each additional component is integrated with the main frame by fitting it around a portion of the main frame and then applying a moulding process to the main frame together with the or each additional component.
Thus, by means of the present invention, one or more additional components including thermoplastic material are consolidated into the structure of a main frame formed using thermosetting material, thereby improving the vibration damping properties of the games racket frame.
REFERENCES:
patent: 4028477 (1977-06-01), Goppel et al.
patent: 4070019 (1978-01-01), Segal et al.
patent: 4604319 (1986-08-01), Evans et al.
patent: 4643857 (1987-02-01), Cousin et al.
patent: 4770915 (1988-09-01), Nakagawa et al.
patent: 4913434 (1990-04-01), Fischer
patent: 5076872 (1991-12-01), Nakagawa et al.
patent: 5770313 (1998-06-01), Furumoto et al.
Chiu Raleigh W.
Dunlop Slazenger Group Limited
Lorusso & Loud
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