| 摘要 |
The invention relates to a device for injecting a thermoplastic material in a liquid state into a moulding cavity. Close to the moulding cavity (4), a centering and thermal insulation ring (31), which is arranged between the outer peripheral surfaces of an injection nozzle (14) and the inner peripheral surfaces of the cavity (6) of a matrix (1) partially defining the mould cavity (4), is provided with two lips (49,50) in the direction of injection (2), one of which being internal and the other external, wherein at least the internal lip (50) is flush with an inner peripheral surface (8,9), which flares out towards the rear, of the cavity (6) of the matrix (1) in order to define a chamber in the matrix, said chamber (24) leading outwards via an injection opening (7), and a closed chamber (51). The amount of thermoplastic material which is lost with each colour change is reduced, tightness is increased vis à vis leakages and thermal insulation is improved between the nozzle (14) and the matrix (1).
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