Patent GB-903558-A (GB)
Title: A machine for the manufacture of containers
IPC: B29C45/03
Filed: 1958-08-26
Abstract: 903,558. Injection moulding of containers. MAINARDI, T. Aug. 26, 1958 [Sept. 3, 1957], No. 27270/58. Class 87(2). In the manufacture of nozzle-headed containers, tubes 200 are fed along guides 801, Fig. 17, on to mandrels 500 and cut to length, and the nozzle heads are then injection moulded on to the ends of the tubes. The guides 801 extend freely through apertures in brackets 701a, 702a and are supported by the mandrels 500 during feeding of the tubes. Disposed within each aperture is an annular diaphragm 706, Fig. 21, which can be contracted to grip the tube 200 by compressed air supplied through passages 709 in the bracket 701a. Similar tube-gripping means 702 are provided in the lower bracket 702a, and also at 703, Fig. 5, surrounding the mandrels 500. Feeding of the tubes 200 on to the upwardly directed mandrels 500 is effected by means of a fluid pressure cylinder 724 and piston 723 connected to bracket 701a, the gripping means being operative during the downward stroke of the piston 723 and inoperative for its return stroke. The tubes are cut to length by means of a blade 749, Fig. 20, mounted on an ovalshaped carrier 741 which is slidable in grooves 739, 740 in a housing 738. When the housing 738 is rotated by means of a self-braking electric motor 730, Fig. 17, an eccentric bob weight 744 moves the carrier 741 in its slots so that the blade 749 contacts and cuts the adjacent tube 200. When the motor stops, the blade 749 is moved clear of the tube by means of springs 745, 746. The motor is connected to the housings through a pinion 731 and gear rings 733 . . . 736. While cutting is being effected, the tubes are being held by the gripping means 702, 703. The mandrels 500 project from a cross-bar 700 which also supports the gripping means 703 by means of arms 703c, Fig. 5. The crossbar 700 is pivoted on toothed trunnions in the side arms 400e, 400f of a carrier 400 which is vertically reciprocable in the frame 100 of the machine by means of a fluid pressure cylinder 482 and piston 1000. The cylinder 482 is secured to the frame 100 of the machine and its piston rod 1000 to a bridge portion 400h of the carrier. After cutting of the tubes by the blades 749, fluid is admitted to the cylinder 482 to move the carrier 400, cross bar 700 and mandrels 500 (with the cut lengths of tube) away from the guides 801. The mandrels 500 are then rotated through 180 degrees by means of fluid-operated racks, Fig. 6 (not shown) engaging the toothed trunnions of the cross-bar 700. The mandrels then point downwards towards the mould 300, and cams 700l, Fig. 5, on the cross-bar 700 engage push rods 798. The piston rod 1000 is then moved to the limit of its downward stroke, thus engaging the push rods 798 with mould stops 3001, registering the ends of the mandrels in the dies and depressing the mould against its supporting springs, Fig. 7 (not shown). Granular plastics material (e.g. polyethylene) in a hopper 145, Fig. 15, is forced by a piston 48a into a vertical duct 60 and by a piston rod 70a through a nozzle 41a into a die to form the head and nozzle on the end of each tube 200. The piston 48a has a blind bore which is a sliding fit over a spigot 44l formed on a block 44 disposed in a cylinder 43. The block 44 has axial splines 44a connected by inclined passages 44b to a block bore 44c in which is located a slidable non-return valve 45 provided with radial ports 45b and a grooved head 45e. A check valve 90a prevents discharge of plastic material through the nozzle 41a until the pressure due to piston rod 70a exceeds that produced by a spring 31 on the valve 90a. Thermostat-controlled heaters 49, 49a are provided, and coolant is circulated through the interior of the mould. After injection, the cross-bar 700 and mandrels 500 are raised and given a partial rotation to the position seen in Fig. 1 (not shown). The tube-gripping device 703 on the mandrels is relaxed and fluid is forced through a passage 20, Fig. 19, in the cross-bar 700 and through bores 500i into the interior of the mandrels. This fluid moves a piston 511 and hollow spindle 506 outwardly against the action of a spring 510 so as to displace the containers along the mandrels. When orifices 501 in the hollow spindle 506 are uncovered fluid passes to the space between the containers and mandrels to force the containers off the mandrels and into a receptacle. The effective length of the mandrels 500 can be varied by means of a worm 500m engaging a worm gear portion 5001 of the mandrel which is screwthreaded into the cross-bar 700 at 500n. The tubes 200 may be fed to the machine from spools, or direct from an extrusion machine. Figs. 11... 14 (not . shown) illustrate different types of nozzle heads. Where the nozzle is screw-threaded, the die is formed with a corresponding but deformed tapping so that axial extraction of the moulded threads will rectify the deformation produced by the die. The threaded nozzles are tapered to assist extraction. In Fig. 13 (not shown) a closure plug is moulded with the head of the container and subsequently cut off and reversed for insertion in the nozzle.