Patent GB-1428791-A (GB)
Title: Blow moulding method and apparatus
IPC: B29C49/04
Filed: 1973-03-05
Abstract: 1428791 Blow-moulding ETHYL DEVELOPMENT CORP 5 March 1973 [8 March 1972] 10550/73 Heading B5A Blow-moulding apparatus comprises means to supply a tubular parison, two pairs of blowmould halves each movable between the parison supply station and a blowing station, mould opening and closing means, and two blow pin assemblies one mounted at each blowing station. As shown, the apparatus comprises a frame 36, Fig. 2, of base 37, sides 38 and ends 39 with brackets 45, 46. Mould assemblies 47a, 47b run on wheels 48, Fig. 6, in tracks defined by front rails 42, 43 and rear rails 40, 40c on sides 38, the tracks having upwardly curved end sections 44, Fig. 15, and are moved thereon by cylinder 72 acting through shaft 95 and pivoted links 98-100 connected to the frame 49 of the assemblies 47a, 47b. Frame 49 comprises a base 50 and sides 51 connected by sleeves 52, 53 through which pass tie rods 54, 55. Tie rods 54, 55, Fig. 3, have a front platen 56 fixed thereto and carrying mould half 56a, a rear platen 59 slidable thereon and carrying mould half 59a and, on threaded ends 61 thereof, a forward platen adjustment assembly 62. A further cylinder 72, Fig. 6, rotates shaft 81 and cam wheel 90 therewith for mould opening and closing by means of rods 69a, 69b connected to platen 59 and rods 64a, 64b connected to assembly 62, the inner ends of rods 64, 69 following J-shaped slots in cam wheel 90. The upper frame 107, Fig. 8, of each blowing assembly 108 is mounted on brackets 46 or 47 and carries cylinder 109 fixed thereto. Its piston-rod 111 moves a support frame 114 along guide rods 120 also fixed to frame 107. A blow pin 117 is mounted on support frame 114 and is passable through a hole 122 in a stripper plate 119 on rods 120. The forward platen adjustment assembly 62 (also in Figs. 23, 24, not shown) may be provided to adjust the space between the platens for different sizes of blow-mould. Means are also provided (Fig. 25, not shown) to move cylinder assembly 72 between the sides 51 of frame 49 to shift mould closure plane and allow exact alignment with extruder 47. The blow pin assembly 108 may comprise three blow pins (Figs. 12, 13, not shown) for use with multi-cavity mould parts. A pedestal assembly 169, Fig. 1, may provide adjustment of the blow-moulding assembly relative to the extruder head 47 in all three planes (Figs. 17-19, not shown) or merely in the vertical plane (Figs. 20- 22, not shown). A travel cushion assembly (229, Figs. 26-28, not shown) cushions the travel of the mould assemblies 47a, 47b over the last half of their travel. In operation, a parison is continuously extruded from head 47 and one of the moulds is moved across to the parison supply station beneath it and closed on the parison which is severed by a knife (not shown). The mould assembly is then moved back to its blowing station while the other mould assembly is moved to the extruder. Blow pin 117 is lowered into the first mould, severing neck flash from the parison against the neck portion of the mould and blow-moulds the parison into contact with the mould. Blow pin 117 is then raised, stripping the blown container and flash against plate 124. The container may fall into a storage box or on to a conveyer belt. The power cylinders may be pneumatic. The blow-moulds may have channels for cooling fluid.