| 摘要 |
Accumulating heads to produce preliminary blanks for the production of hollow plastic articles such as containers by the blow process (known as the "joint extrusion process"), such blanks, being of cylindrical "tube" configuration and also laminates which are layers of different material. Suitable accumulating tube heads for the joint extrusion process are disclosed wherein the layers retain their relative positions and thickness ratios over their entire length up until expelled from the nozzle. The accumulating heads each have a plurality of coaxial annular feed passages, each fed from a different extruder, which open into an annular space and passage. The annular passage is located between the facing walls of concentric inner and outer packing washers. Concentric inner and outer annular pistons slide on the opposed surfaces of the washers and reciprocate in the reservoir chamber for expelling the plastic laminate through an annular nozzle conduit and an annular nozzle to form the laminated preliminary blanks.
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