| 摘要 |
<p>1,090,553. Injection moulding. DOW CHEMICAL CO. July 15, 1965 [July 23, 1964], No. 30118/65. Heading B5A. A thermoplastic article having high multidirectional molecular orientation is moulded in a mould, one element of which is rotatable, means being provided for sensing when the cavity is filled, and means for terminating the rotation a predetermined time after the mould is filled or after a predetermined number of revolutions. The article may be produced in injection moulding apparatus similar to that in Specification 1,067,100, or by impact moulding (Fig. 3, not shown). The means for sensing when the mould is full may comprise a glass-insulated electrode (58) arranged flush with the mould surface, and connected to a source of power sufficient to cause sparking between the electrode and one of the mould elements. The thermoplastic material quenches the sparking and results in a signal being passed to control means to start the counting. After a predetermined number of revolutions the rotating mould element is stopped. In a preferred embodiment (Figs. 4, 5, not shown) the sensing means comprises a thermistor (90). In a modification a time delay relay terminates the rotation a predetermined time after the mould is filled.</p> |
