GB1399923A - Machine for manufacturing plastics bottles and other hollow articles - Google Patents

Abstract

1399923 Extrusion blow-moulding B STRONG 1 Sept 1972 [27 Dec 1971] 40734/72 Heading B5A Extrusion blow moulding apparatus comprises frame 1A, 1B, 19, 2A, 2B, 27 on which are mounted carriages 3, 5 connected by rods 22A, 22B and traversed on rollers 9, 11, respectively, in a horizontal path by rod 13 of cylinder 12. Front cylinders 4A, 4B with mandrels 14A, 14B and blowing air orifices 10A, 10B are mounted on carriage 3. Carriage 5 carries extruder 6 with crosshead 7 with pre-blow orifices 8A, 8B and rear cylinders 4C, 4D having mandrels 14C, 14D and blowing air orifices 10C, 10D. Rods 17A, 17B carrying heated knife 15 are also carried by carriage 5 and traversed by cylinder 18. A front platen 33 carries mould halves 16A, 16E mating with mould halves 16B, 16F, respectively, on central platen 34. Also on platen 34 are mounted mould halves 16C, 16G which mate with mould halves 16D, 16H respectively, on platen 35. From the position of Fig. 1, parisons 28A, 28B are extruded between mould halves 16A, 16B, 16E, 16F which are closed to seal the lower end thereof while mould halves 16C, 16D, 16G, 16H open to release the formed articles (30C, 30D, Fig. 2, not shown) therein, platen 34 moving in the direction Y, platens 33, 35 in the opposite direction. The enclosed parisons are then partially pre-blown by air from orifices 8A, 8B (Fig. 2), leaving upper flared sections (29A, 29B) after severing thereof by rightward movement of knife 15. After stripping of articles (30C, 30D) from the right-hand station, carriages 3, 5 are traversed to the right so that blowing mandrels 4A, 4B may be lowered into the left blow moulds halves 16A, 16B, 16E, 16F to form articles (30A, 30B, Fig. 3, not shown) and fresh parisons 28A, 28B may be extruded from crosshead 7 between right mould halves 16C, 16D, 16G, 16H which are then closed and mould halves 16A, 16B, 16E, 16F opened. The new parisons are then severed by knife 15 and pre-blown as before. Bottom flash (31, Fig. 2) on the formed articles may be removed by grippers before or after mould opening. Ejection is effected by air from mandrels 14 which also sever flared sections (29) at points (32) by co-operation with the mould-parts. Sections (29) are stripped from mandrels 14 against carriage 5 as they are raised by cylinders 4 before traversing of carriages 3, 5. Extrusion is interrupted during traversing of carriages 3, 5 but may be made continuous by provision of cylinder (59, Fig. 2) which pivots extruder 6 about point (75) during this time. In Figs. 6, 7 (not shown), there is only one mould at each station requiring a stirrup (40, 41, 42) for vertical movement of right-hand blowing mandrel (38). In Figs. 8, 9 (not shown), the extruder (64) is vertically reciprocable. An electrical, mechanical or fluid pressure operated timing mechanism may be used.