| 摘要 |
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 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 or other of the hollow frame. |
