GB1395727A - Blowmoulding apparatus - Google Patents

Abstract

1395727 Blow-moulding METAL BOX CO Ltd 20 Oct 1972 [4 Nov 1971] 51221/71 Heading B5A Blow-moulding apparatus comprises a plurality of openable moulds movable serially along a path through a loading station where each mould opens to receive a parison and closes thereon, means to grip and pull the parison from an extruder into each mould and to cut off an appropriate length of parison. As shown, the apparatus comprises a wheel 10 rotating in direction A and carrying moulds 12A-12J openable by pivoting the halves on an axis tangential to wheel 10. A parison 16 is extruded from extruder 14. Each mould opens at position 12A, the parison 16 is fed into it and the mould closed thereon at position 12B and the parison cut off. The parison is expanded by air blow into it as the wheel rotates further and the bottle formed cools before falling out on mould opening at position 12A. Air and water are fed to the moulds through connections (48, 50, 52, Fig. 2, not shown), and trunking (54). Gripping and cutting arms.-Arms 60A-60J, Fig. 3, comprise a cranked tube portion 64 pivoted to wheel 10 at 66 and having a cam roller 68, and an extension 70 slideable in portion 64, carrying jaws 72 and having a roller 76 to govern sliding. Jaws 72 are opened and closed with the mould halves. Arms 60A-60J are spring-biased into contact with the leading face of each mould, but may be advanced to contact the trailing face of the preceding mould by contact of roller 68 with a fixed cam (80). In Fig. 3, the jaws of arm 60B are gripping the parison 16 at the leading face of mould 12B and those of arm 60A grip it at the trailing face of this mould, the latter having cut the parison on mould closure. As the wheel 10 rotates, roller 76 of arm 60A enters a fixed cam channel (82), drawing extrusion 70 inwardly and with it the cut-offend of parison 16. As the wheel 10 rotates further, arm 60A hauls off further parison into mould 12A and is allowed to drop back by cam (80) into contact with the leading face thereof. Arm 60J contacts the trailing face thereof to sever an appropriate parison length on closure thereof and so on. Immediately before mould opening, the arm 60 is moved forward slightly and then back by cam (80) to remove tail flash. Mould opening and closing.-Mould halves 100, 102, Fig. 7, are pivoted together on shaft 103 rotatably mounted in holder (104, Fig. 6, not shown), mounted on wheel 10. A crank 108 is pivoted to holder (104) at 110 and links 112, 114 connect it to webs 105, 106 of mould halves 100, 102 for mould opening/closing. The other, bifurcated end of crank 108 engages a boss (120) on a block 116 slidable on a fixed rod 118 as a roller 136 on block 116 follows the surface of cam arm 122 or 124. Each arm 122 or 124 carries a roller 128, 130 which is spring-urged into engagement with cams 38, 40 which are rotated in direction B. For mould opening, arm 122 is urged inwardly by cam 38, pushing in roller 136 and raising block 116 to open the mould. For mould closure, roller 136 moves along the outer surface of arm 124 which is urged outwardly by cam 40, pushing out roller 136 and lowering block 116. Guide cams 138, 140 may be provided. Blowing mechanism.-A blowing spigot (150), Fig. 8, is mounted on an arm 152 which is fixed to a rod 156 sliding in a tube 158 fixed to one of the mould halves. A forked crank member 164 is pivoted to tube 158 at (166), carries a cam roller 168 and is connected by links 172 to collar 160 on rod 156, link 172 also carrying a cam roller 174. A third cam roller 176 is mounted on spigot arm 152. Before mould closure, spigot (150) is held away from the mould axis for parison collection. Cam 182 then contacts roller 176 swinging arm 152 round so that spigot (150) lies on the mould axis. Cam 184 then contacts roller 174, straightening link 172 and pushing collar 160 and tube 158 apart to insert the spigot (150) into the mould for blowmoulding and where it also forms the bottle neck by means of its enlarged portion (194, Fig. 10, not shown), pressing the parison against the mould bore and simultaneously forming and cutting off flash in recess (192). After almost full wheel rotation, roller 168 strikes cam 178 for partial withdrawal of spigot (150) so as to separate neck flash before mould opening. On mould opening, spigot (150) engages stripper plate 154 and swings away from the mould axis. Roller 168 then strikes cam 180 for full retraction of the spigot (150) from the moulded bottle.