| 摘要 |
1,249,586. Moulding gear-wheels. IMPERIAL CHEMICAL INDUSTRIES Ltd. 16 Feb., 1970 [26 March, 1969], No. 15752/69. Heading B5A. [Also in Division F2] A gear wheel has a core 4 of a polyamide substantially free of molybdenum sulphide or p.t.f.e. moulded integrally with a substantially continuous surface skin 5 of a polyamide material containing up to 25% of the weight of the polyamide of molybdenum sulphide or p.t.f.e. The core and skin need not be of the same polyamide, but are selected from nylon 6, nylon 66, nylon 610, and copolymers of nylon 6 and nylon 66. The core may be reinforced with asbestos, glass, or carbon fibres, or with glass or mica plates. The skin may include carbon fibre reinforcement. The gear is formed by a twostage injection moulding process, the core material being injected after the skin material but before the latter has set. A third charge, comprising further skin material, may be injected to insure a continuous skin. |
