Method of forming hollow plastic articles

Abstract

Abstract 758,299. Moulding hollow plastic articles. OWENS-ILLINOIS GLASS CO. Sept. 2, 1954 [Sept. 21, 1953; Sept. 21, 1953; Sept. 21, 1953], No. 25485/54. Class 87(2) In making a hollow plastic article a measured quantity of plastic material is transferred from a main supply into a tubular cavity and separated from the' main supply; then an end part on the measured quantity is initially formed to substantially final form (e.g. a screwthreaded neck part of a container); then a thin-walled hollow tubular part is extruded from the measured quantity but still forms an integral part of the initially formed portion; and finally the hollow tubular form is blown to final shape (e.g. the body of the container). Plastic material is forced through a conduit 13, Fig. 3, into a cylinder 10 where it is compressed by a piston 14 that slides upwardly around a fixed mandrel 11. The leading part of the material is forced into a mould that forms the neck part of a bottle, this mould comprising separable outer parts 15 and a tubular core 16. Then the neck mould and piston 14 rise to the Fig. 4 position, the plastic material being extruded as a tube T from the cylinder 10. Then, Fig. 5, the body mould parts 17 close in on the tube, the bottom of the tube being pinched by the mould to close it, a blade 20 severs the tube from the material in cylinder 10, and air is blown into the tube through core 16 to expand the tube against the mould 17, as in Fig. 9. The waste 21 is trimmed off. In modifications of this method, (a) the tube T may be extruded downwardly, horizontally or slantwise; (b) (Fig. 8, not shown), the blade 20 may sever the tube before the mould parts 17 close in; (c) (Figs. 6 and 7, not shown), a plurality of bottles are formed simultaneously; (d) the tube is severed. then pinched, then blown as in Fig. 11, trimming being unnecessary; (e) (Figs. 12-17, not shown), a larger diameter mandrel 11 is used and; (f), the neck mould is of the modified construction shown in Fig. 20 in which the halves of the neck mould 36 are opened and closed by pins 49. Various combinations of these methods may be used.

Inventors

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