| 摘要 |
1,242,972. Moulding gear-wheels. USM CORP. 10 Oct., 1969 [11 Oct., 1968], No. 49765/69. Heading B5A. [Also in Division F2] A method of making a gear member comprises the steps of (a) providing a mould cavity having mould surfaces including a circular series of gear teeth, (b) placing within the cavity closely adjacent to the teeth and uniformly spaced therefrom a preheated rigid metal annular member of generally uniform cross-section (c) introducing heated thermoplastic material under pressure into the mould cavity to envelope substantially the entire annular member and (d) removing the completed gear member from the mould cavity, in step (b) the annular member being pre-heated to a temperature above that of the heated thermoplastic material in order to retard and control the rate of cooling of the thermoplastic material as it sets. Preferably the metal ring is of steel or sintered iron and the thermoplastic material an acetal. The gear may be the torque reaction member in a harmonic drive mechanism. |
