| 摘要 |
703,970. Blow-moulding plastic bottles &c. LORENZ, F. April 22, 1952, No. 10068/52. Class 87 (2) Apparatus for making seamless hollow articles of thermoplastic material by extrusion of the material through an annular nozzle formed between a sleeve and a plunger which is displaceable relative to the sleeve, the material being subsequently expanded by blowing, is characterized in that the plunger is disposed outside the sleeve and aligned lengthwise with the bore of the sleeve, the plunger and the sleeve extending in opposite directions when viewed from the annular nozzle. The principle of the invention is illustrated in a diagrammatic way in Fig. 4, in which the annular nozzle 1 is formed between a sleeve 3 and a plunger 4 which is outside the sleeve but aligned therewith, the material being extruded through the nozzle by a piston 10 and expanded into contact with mould 7 by compressed air introduced through a channel 12 formed in a plug 9 or in the plunger. Figs. 5 to 9 show an apparatus in more detail, comprising sleeve 3, plunger 4, piston 10, mould 7 and plug 9 with air passage 12, as in Fig. 4. With the parts in the position shown in Fig. 5, plastic material is injected through passage 3a and annular channel 15 into sleeve 3 and thence into the space between plug 9 and mould 7 to form the neck 6 of a container. Then the parts are moved to the Fig. 6 position in which a valve 13 isolates the material 14 within the sleeve from the channel 15, a heating element 15 is moved up to the end of the sleeve, the sleeve is retracted a little way from the mould, and the piston 10 advances to extrude the material 14 through the annular nozzle 1. In the third stage, Fig. 7, the sleeve and plunger 4 descend and air issues from passage 12. The parts descend to the Fig. 8 position, whereupon the heating element 16 is withdrawn from the end of the sleeve and a multi-sectional bottom-forming mould 17, which is linked to the mould 7, is fitted around the sleeve. The extrusion and blowing continue until the final position, Fig. 9, is reached, and the piston 10 is cooled by liquid through passages 18, 19 to facilitate separation of the blown article from the piston. In a modification, Fig. 12, the body of the container may be blown without a mould, in which case the sleeve, piston and heater, Fig. 10, may form an entity which can be charged with plastic material 11, heated, and fitted in the bottom plate 17 of the blowing apparatus. The blown article 8 may be sprayed with drops of cooling liquid to form patterns thereon, or patterns may be formed by cooling the discharge edge of sleeve 3 or the lower end of plunger 4 during extrusion, whereby the material is torn and scars are formed.
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