Patent GB-949747-A (GB)
Title: Packaging method and apparatus
IPC: B65B31/06
Filed: 1962-09-07
Abstract: 949,747. Packaging methods and apparatus. R. A. MAHAFFY, J. R. HARDER, and AMERICAN CAN CO. Sept. 7, 1962, No. 34367/62. Heading B8C. A method of packaging a product, e.g. luncheon meat, in a container and evacuating same consists of forming the containers from two sheet portions sealed around their peripheries, an opening having been cut in one of the sheets and being covered by the imperforate sheet, evacuation being effected by moving the imperforate sheet away from the opening to form a channel and connecting the channel to a vacuum source. Finally, the surfaces of both sheets are sealed around the opening to hermetically isolate it. In one embodiment, a sheet 1 is drawn from a roll by a draw-roll unit 3 under a roller 4 where it is applied to an endless chain of intermittently moving trays 5, each mounting a pair of clamps 6, Figs. 3, 11, which open and close to secure the sheet to the surface of the trays. The sheet is then carried under a heater 7, so that in the next position of the tray the sheet can be drawn into cavities 9 in the trays by suction applied through a connection 85. There are two cavities in each tray so that the sheet is formed into a pair of cup-like containers 10. Additional suction connections 85a, 85b, Fig. 1, also serve to withdraw air from under the cups 10 in positions e, f respectively, in order that the initial forming process should not cause any retrograde motion of the sheet. In lieu of suction moulding, fluid pressure of mechanical means may be used (not detailed). A conveyer 8, conveys the articles to be packaged to the trays for manual loading on to the cups. The trays and sheet now move to a position g where a knife 13, on a vertically reciprocating head 12 descends to cut a slit 14 in the sheet between each pair of cups. Another sheet 15 is now applied to the top of sheet 1 and in position h the two sheets are sealed around the periphery of the tray, except for a small region between the cavities, by heat-sealing bars 19 on the head 12. In this position the sheets are cut transversely between the trays by a knife 21. The partially-sealed filled containers now move to position j under sealing clamp 22 on the head 12 which seals them from the atmosphere except for the opening through the slit 14. A pin 91 mounting a separator 90, Figs. 9, 11, is now moved into the slit to engage sheet 15 and lift it from sheet 1 so that a channel is formed between the cups 10 and the slit. An assembly 93 also moves with the separator and engages the underside of the tray so that air can be withdrawn from the cups through 94. If it is desired to fill the packages with inert gas, the separator may have a bore connected alternatively to a vacuum and the gas (Fig. 15, not shown). The cups are then completely sealed by a sealing bar 23 which descends immediately after separator 90 has been withdrawn. Finally, the packages are moved to position l where suction cups 25 carry each pair on to conveyer belts 27 after the clamps 6 have been disengaged by an actuator 96. The pairs are cut into individual packages 102, by shear knives 28, while travelling along the conveyer belts. In an alternative embodiment (Fig. 12, not shown), each tray has one pocket only and the slit in the lower sheet is made within a complete peripheral seal and at one side of the package. The separator and final sealer are then mounted to one side of the path of tray movement instead of centrally. The tray pocket sizes may be varied by inserting shaped blocks (Fig. 7, not shown).