GB1425638A - Method of blow moulding hollow articles - Google Patents

Abstract

1425638 Moulding glass tubular blanks RHONE-PROGIL 16 Feb 1973 [16 Feb 1972] 7721/73 Heading C1M [Also in Division B5] A molecularly oriented article particularly a bottle, is formed from a cold tubular preform by heating it, placing it into a blow mould which is closed thereon, longitudinally drawing it in the closed mould by simultaneously moving the two ends of the preform apart and blowmoulding. As shown in Fig. 3, mould halves each comprising three parts 7, 8, 9 and 10, 11, 12 are mounted on securing plates 5, 6 on platens 3, 4 for opening and closing by piston rods 1, 2. The upper parts 7, 10 are vertically movable by rod 16 connected thereto by horizontal bar 17 and vertical columns 18, 19 movable on bar 17 on bushes 24. Similarly, lower mould parts 9, 12 are vertically movable by rod 20 via bar 21 and columns 22, 23. In operation, a tubular preform (25, Fig. 1, not shown), held by spring clip 28 on a. carrier 26 which has a blowing passage 27 is heated and inserted into the open and contracted mould (Fig. 1) which is closed on to it so that it is held by neck mould parts 29, 30 and gripping means 31, 32, leaving waste portion 34 (Fig. 2, not shown). Rods 16, 20 are then moved apart to expand the mould, leaving spaces 35, 36, and to draw the preform, which is thus contracted at 37, Fig. 3, The preform is then blow-moulded by fluid through passage 27 and ejected. If the article has a recessed base 33, the lower mould parts 9, 12 may be lowered before ejection. In the embodiment of Figs. 4, 5 (not shown), each mould half comprises two parts (43, 44) and (45, 46). The mould parts may provide strengthening ribs, may be heated or cooled, and may be also be vented or porous to allow escape of air from between preform 25 and the mould. The material may be polystyrene, polyvinyl chloride, superchlorinated polyvinyl chloride, polyolefins, e.g. polyethylene, polypropylene, or glasses. The machine may be controlled manually or automatically being programmed or controlled by electromagnetic, pneumatic, hydraulic or mechanical systems. Blow-moulding may be effected after or simultaneously with drawing. The properties of the article may be modified locally by varying the heating and/or cooling with the speed of longitudinal movement and/or the pressure of blowing fluid.