| 摘要 |
1,254,374. Seaming non-metallic sheet material. FR. HESSER MASCHINENFABRIK-AG. 7 March, 1969 [7 March, 1968], No. 12215/69. Heading B5K. [Also in Division B8] A packaging container constructed from a multi-layer packaging material has an overlap seam 16 protected by a cover band 18 composed of a carrier foil 21 and at least one plastics layer 19 weldable to the inner layer 13 of the container body, the arrangement being such that a part 24 of the band 18 lies between the overlapping seam margins 17, 25 of the container body and the band 18 passes around the edge of the inner margin 17 to lie on the inside of the container and abut against the inner side of the margin 17, the abutting part 22, 23 of the band 18 being folded through 180 degrees on to itself. The packaging material may comprise outer polyethylene layers 12, 13, an aluminium foil layer 14 and a paper layer 15. Preferably, the band 18 comprises an aluminium foil layer 21 sandwiched between plastics layers 19, 20 of the same material as the layers 12, 13. Adjacent plastics layers of the band and the container body are joined by welding. In one embodiment, Fig. 1, the parts 22, 23, 24 of the band 18 are of substantially equal width. The band 18 may be extended outwardly around the edge of the margin 25 and folded around itself and welded to the layer 12, shown in broken lines. In a second embodiment, Fig. 2 (not shown), the part (23) is wider than the parts (22), (24) together. To make a tubular container having the seam of Fig. 1, the band 18 is fed from a supply and passes between rollers which form two longitudinally extending grooves defining the parts 22, 23, 24. The part 22 is folded on to the part 23 and the part 24 is folded on to the part 22 and then outwardly again, Fig. 7 (not shown). The strip is applied by rolls to the edge 17 of a web of packaging material, is welded thereto by warm air heated by electrical resistors 31 and discharged through a nozzle 32, Fig. 10, is pressed by rollers (33), Fig. 11 (not shown), and is cooled by an air blast, Fig. 12 (not shown). The web is formed into a tube-like structure 26, Fig. 13, so that the edges 17, 25 are adjacent to each other. Hot air is applied by an air jet and the edges (17), (25) are pressed together by rolls (35), (36), Fig. 14 (not shown). The tubular web is subdivided into individual containers. In a modification, the web is subdivided into sections 11a, Fig. 17, prior to being formed into a tube and, after heating of the edges, is formed into a tube about a mandrel 45 by a resilient pressing tool 41 secured to a drive 40 on which are positioned two folding tools 42, 43 which are moved against the mandrel 45. The edges of the section 11a are pressed together by a tool 46. |
