Patent GB-811866-A (GB)
Title: Method and mould for moulding tubular containers from plastics material
IPC: B29C45/14
Filed: 1956-05-23
Abstract: 811,866. Moulding tubular containers. REGOMA CO. Ltd. May 23, 1956 [May 28, 1955], No. 15954/56. Class 87(2). Tubular containers are moulded by placing a tubular blank in the die of a mould and injecting plastic material into a neck-forming part of the die through a passage which is closed after injection of the material but before separation of the moulded article and the die. Fig. 3 illustrates a procedure in which a tubular blank 1 of plastic material is disposed around a hollow mandrel 2 and then inserted within a die 5. The mandrel is fitted with a loose head 3 having a projection 6 which enters a bore 7 in the die. Within the mandrel is inserted an injection nozzle comprising two separable sleeves 9, 14. The upper end of sleeve 14 terminates in a head 10. In operation the sleeve 14 is pushed upwardly as shown in Fig. 4, the mandrel head 3 being raised off the mandrel and a channel 15<SP>1</SP> being formed between the various parts. Plastic material then passes upwardly through the space 12 between the sleeves 9, 14 and through the channel 15<SP>1</SP> into the mould cavity C where a screw-threaded container head is formed and welded onto the upper end of the blank 1. The nozzle is heated by fluid passing through pipe 13. In the space 11 between the nozzle and the mandrel is disposed thermal insulation or a cooling fluid. The die may be cooled or kept at a constant temperature by cooling ducts (not shown). To discharge the article the nozzle is closed and withdrawn from the mandrel and the (onepiece) die is unscrewed, Fig. 7, a rod 17 being pushed down against mandrel head 3 to keep it in place during unscrewing. Compressed air is then blown into the mandrel to separate the head 3 therefrom and disengage the formed container. The die may be in several parts, disengagement being effected radially : or there may be a combined axial and radial disengagement. Figs. 9 and 10 show an apparatus for carrying out the operations described above, comprising an intermittently-rotating disc 18 which carries six mandrels 2, 3 and six dieclamping members 19, at the positions I .... VI, four transportable dies 5 and a dietransporting arm 24 pivotally mounted at the centre of the disc. In operation, (1) the disc being stationary, a tube blank 1 is placed upon the mandrel which is at position I. (2) The arm 24 (at position V) rises and lifts the die 5 which is at that position off a moulded container. The arm then swings from position V to position I, descends to lower the die over the blank, the die resting on the disc, rises and swings back to position V. (3) The disc turns clockwise through 60 degrees, the assembly at position I being thus indexed to position II together with its clamping member 19. During this turning movement the clamping member turns clockwise through 90 degrees and then descends to clamp the die down onto the disc. (4) At position II the injection nozzle is inserted into the mandrel and moulding is effected as des -  cribed above. (5) As the disc rotates stepwise the material in the mould cavity hardens. Between positions IV and V the clamp is removed. (6) At position V the die is removed and carried to position I, as described above. (7) At position VI the moulded container is ejected. The dies may be cooled by a stream of air or of solid CO 2 . The clamps may be controlled by toggles, levers or hydraulic means. Fig. 12 shows a modified one-piece mandrel having injection orifices 33 therein, and a modified nozzle having orifices 35 which can be aligned or misaligned with orifices 33 by rotation of the nozzle about its longitudinal axis. In Fig. 13 the mandrel has a fixed part 39 and a movable part 40 and the nozzle has a fixed part 43 and a movable part 42. When moulding has been partly effected, as shown, the parts 40 and 42 are raised to shut off the supply of material and complete the formation of the container head. In a modification of Fig. 13, Fig. 14 (not shown), the mandrel is in one piece which rises with the nozzle part 42 to shut off the supply and complete the moulding. Fig. 15 shows injection from outside the mandrel 53, the supply being shut off by pushing the mandrel and the outer nozzle part 55 upwardly. In modification of Fig. 15, Fig. 16 (not shown), the shutting-off surfaces S extend horizontally.