Games racket
AssigneeDunlop Limited
InventorRobert C. Haines
Life of this patent
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AssigneeDunlop Limited
InventorRobert C. Haines
Estimating the term…
The invention relates to a method of making a hollow frame for a games racket by injection moulding of fibre-reinforced thermoplastics material around a fusible core. The core is formed with holes through it corresponding to the desired stringing holes. The core holes are stepped so that the hole in one face of the core is larger than the hole in the opposite face. A stepped mould pin is inserted through each hole through the core, the pins being of such dimensions that the bore of the larger hole is completely filled giving positive location but the bore of the smaller hole is of greater diameter than that of its corresponding portion of the pin. Injection of the thermoplastics material, followed by setting of that material and then removal of the core results in a product having reinforcing tubular projections inwardly from one wall of the hollow frame.
A method of making a frame for a games racket, the frame comprising a hollow head and a shaft, said head being defined by inner and outer circumference walls and having stringing holes through said walls, which method comprises the following steps:
A method according to claim 14, in which the larger holes are all formed in one of said faces of the core and the smaller holes in the opposite face of the core.
A method according to claim 14, in which the edges defining the larger holes in the core are radiused.
A method according to claim 14, in which the smaller bore of the stepped holes extends through at least half the thickness of the core.
Dependencies are inferred from the claim text.