GB713419A - Improvements in or relating to the production of hollow moulded articles from thermoplastic material - Google Patents

Abstract

713,419. Glass. LACRINOID PRODUCTS, Ltd., and HAGEN, R. Dec. 24, 1952, No. 32715/52. Class 56 [Also in Group V] The leading end of an extruded tube 2 Fig. 1, of a length greater than that of the article to be produced, is passed over a compressed air nozzle 3, and a severed length of the tube is enclosed between the sections 4, 5 of a mould, the leading end of the tube being pinched by the mould into sealing contact with the nozzle and the other end of the tube being sealed between the mould sections. Then air is blown into the tube to conform it to the shape of the mould (Fig. 2). In Figs. 1 and 2 the extruded tube is of smaller cross-section than the mould, but it may be of larger cross-section, as in Fig. 4, in which case excess material 20, Fig. 5, is squeezed out at the sides. As shown, a bottle having an open neck is formed, but for. making other articles the open-ended portion may be sealed or cut off: other articles mentioned are balls, dolls, ampoules and fountain-pen bodies, and the tubes described in Specification 709,370. The processes illustrated are for batch procedure, but continuous production may be achieved by (a) continuously extruding a tube to a succession of sectional moulds which move past cutting and blowing stations, each mould incorporating a reciprocating air nozzle which at the stages required is brought into communication with a scource of pressure air; or (b) feeding at spaced intervals a succession of batches of material to an extruder which delivers an extruded tube between the sections of a mould, the subsequent operations of blowing and ejection being effected without moving the mould relatively to the extruder, and a single air nozzle being arranged to reciprocate from a position in which it registers with the extruded tube to a position in which it assists in discharging the formed shape.