IE42940L - Production of hollow thermoplastic bodies. - Google Patents

Abstract

1480322 Blow moulding SOLVAY & CIE 5 Jan 1976 [7 Jan 1975 27 June 1975] 166/76 Heading B5A A blow-moulding lay-out (see Fig. 1) comprises an extruder 1 which feeds a tubular parison to a series of axially aligned split moulds carried by a rotary carrier 2. The moulds blow the parison into preforms each having a final neck configuration above which is located a false neck (see Fig. 3). The preforms are removed from the moulds by a release device 3 and presented to the hinged jaws (see Figs. 4 and 5, not shown) of carriers carried by an endless chain 4 whence the false neck is removed by a deflashing device 5. The deflashed preforms are passed around a cooling device 8, at which a cooling fluid, such as liquid nitrogen is introduced into the preforms, and fed to a series of blow moulds carried by a rotating carrier device 7 via an oven 6 in which they are brought to molecular orientation temperatures. Finally, the blown articles are presented to a heating device 9 to thermally stabilize them against stress cracking. All the elements of the lay-out are driven through suitable gearing and chains (see Fig. 2, not shown) from a single motor to ensure synchronization and the chain is tensioned by a pair of adjustable devices 11 and 12. The chain is actually driven either by drive gears each located in a different stretch of chain between the tensioning devices or by the carriers 2 and 7 themselves. One of the drive gears may be attached either to the release device 3 or the deflashing device 5. The preform is blown from the parison by a needle 41 which pierces the false neck of the preform and which is carried by a block 43 reciprocable by a bent lever 52, 50 actuated from a fixed cam by a follower 51. The needle engages the end of a holding screw 44 having a central channel in communication with that of the needle at one end and at the other end with a source of fluid via radial passages 45 in the screw and passage 47 in the block 43. The needle is not withdrawn after the mould is open to retain the preform in the mould half 39 prior to ejection. Retention and ejection may alternatively be effected by an undercut recess 67 (see Fig. 6) in the mould wall and a reciprocable plunger 65 located in the base of the recess. [GB1480322A]