GB1096548A - Method and apparatus for blow molding - Google Patents

Abstract

1,096,548. Blow-moulding; reciprocating extruder. SHIN-ETSU CHEMICAL INDUSTRY CO. Ltd., and S. TERAOKA. Nov. 18, 1965 [Nov. 20, 1964], No. 49075/65. Heading B5A. In an extrusion-blow moulding process, a parison preferably tubular [a, Fig. 1) is extruded from a downwardly-directed extruder head (6) mounted above at least two moulds (9, 10), the extrusion die being vertically reciprocable relative to the moulds, and extruding on the upward stroke. During the subsequent downward stroke, the parison is fed to one of the moulds (9 in Fig. 2, not shown) and it is then severed from the die (during which the upper end of the parison and the lower end of the next parison may be sealed), and blown while the next parison is extruded on a further upward stroke of the head (6). The moulds (9, 10) are reciprocated horizontally relative to the head (6) to align each in turn therewith while the other is cooled and opened for-removal of the article. Apparatus shown in Fig. 1 comprises a plasticizing and feed device (4), a downwardly-directed extrusion head (6) connected thereto, means for supporting the moulds e.g. movable platens 14, 141 mounted on guide rails and a fixed platen, 15, mounted between the movable platens, all of which are mounted on a movable carriage, 11, and operated by hydraulic piston (16) so as to align each mould alternately with the extrusion head (6), means for opening and closing the mould halves (9, 91, 10, 10<1>), e.g. hydraulic pistons (13, 131), means for moving the extrusion head vertically relative to the moulds, e.g. hydraulic pistons (7, 7<1>), and means to inject fluid into the parison to expand it, which may pass through the centre of the extrusion head.