GB1342625A - Injection moulding apparatus for heat plasticized material - Google Patents

Abstract

1342625 Injection moulding nozzle VULCAN CORP 18 March 1971 7254/71 Heading B5A A plurality of moulds 15, each defining a pair of "right" and "left" shoe insole cavities, e.g. 18, containing a two ply insert piece 17 between which injection is effected, and provided with a sprue bush 35, are successively indexed upon a rotary table 9 to an injection station, whereat injection into each cavity is simultaneously effected from one of a pair of injection nozzles 48, 49 which are simultaneously displaceable each by a fluid piston motor, e.g. 50, between a retracted position within a block 42 heated by electrical heaters 67 and whereat transverse and axial nozzle passages, e.g. 65, 61 are obturated from block passages, e.g. 70, 71 connecting to a passage 72 from a pressurized source of thermoplastic, and an injection position advanced from the block 42 whereat each conical nozzle head e.g. 63 is in abutment with a bush 35 and nozzle passages 65 are in registry with the passages 70 to permit injection from the passage 72 into each mould cavity 18. Each mould 15 comprises a lower part 23 and an upper part 24 which is separable therefrom by a bell crank lever 28 operated by a fluid pressure piston 28, and at the injection station the table 9 and mould are clamped against a bolster 13 by a clamp engaging a plate 25 to which the upper mould part 24 is attached. The rotary table 9 indexes at several mould cooling stations, a station at which the moulds are opened and the insoles discharged, and a station at which is inserted the insole piece 17 for the lower ply thereof to locate at an opening therein around a sprue bush nipple 37 permitting the injection between the plies. The block 42 is mounted in spaced insulating relationship 45 beneath the bolster at trunnions located within grooves or spaced legs 14 which support the bolster 13. The passage 72 extends from a screw injection pressure source through an electrically heated barrel 75 coupled to the block 42 for stabilizing it on its trunnions. In operation, the fluid pressure motors 50 are actuated through a solenoid reversing valve, from a limit switch actuated by the mould clamp, the injection screw being actuated through an injection period timer from an upper limit switch actuated by an arm 57 attached to the piston-rod of motor 50, the timer also acting to reverse the solenoid valve for retraction of the nozzles which, via the arm 57, actuates a lower limit switch which actuates the drive means indexing the table 9. The temperature of the plastics material injected, with respect to the timer controlled injection time, is controlled to ensure that. the sprue breaks within the insole.