GB1178716A - High-Strength Container and Container Blank having Seamless Bottom Walls, and Method of Forming Same - Google Patents

Abstract

1,178,716. Forming and erecting boxes; blow-moulding. CHEVRON RESEARCH CO: 5 April, 1967 [5 April, 1966], No. 15594/67. Headings B5A and B5D. [Also in Division B8] Plastics blanks 15 are produced and erected into boxes having a top closure and a reentrant seamless bottom (97), Figs. 11, 13 (not shown) comprising tuck-up panels (100), (101) adhered to a bottom panel (98) (see Division B8) by producing an array of joined pairs of blank preforms 12 by blow moulding or extrusion and severing the array into preform pairs 12 and then individual preforms which are flattened, printed, scored and erected into the completed containers. Palletized plastics material from a hopper 11, Fig. 1, is heated and passed through dual-head dies 23 to form a soft parison 22, portions of which are successively sealed between the two hinged halves 20a, 20b of each of a series of water and/or air cooled moulds arranged on a rotary wheel 21 and closed by air cylinders 24. A hollow blow needle (not shown) is placed within the mould and penetrates the parison 22, forming blank preform pairs 12 connected by webs 12a. Each blank preform pair 12, Figs. 2-4 (not shown) has closed opposite arcuate edges (29), is elliptical in cross-section and may be circular in central cross-section (28). A cutting device 25 severs the web 12a and cuts each preform pair 12 across its central portion (28) into individual preforms which are aligned by a guide 26 relative to rollers 24 between which they are flattened. First and second printing and back-up rollers 44, 45 with an inking mechanism 46 print each side of a preform after which it passes through an ink dryer 47. Scoring rollers 51, 52 with back-up rollers 53, 54 produce fold lines defining side and end panels, Figs. 7 and 8 (not shown) and a second pair of rollers 55, 56 cut the preforms along their upper edge (27), Fig. 5 (not shown). Waste material is then removed from the completed blanks 15 which are mechanically stacked and packed. The blanks 15 may be fed to a mechanism 172, Fig. 16, where they are formed with rectangular cross-section and then fed to a mandrel assembly 146 upon which they are mechanically indexed to erecting stations where the tuck-up panels (100), (101) are formed and rotated into contact with the bottom panel (98) and adhered thereto. An air blast at a stripper 170 removes the completed containers which are then filled and secured at the top closure. The plastics material may be an aliphatic polyolefin such as polyethylene or polypropylene, a vinyl polymer or copolymer, e.g. of vinyl butyral and vinyl chloride, or an acrylic polymer or copolymer.