| 摘要 |
1,187,055. Folding and welding bag bottoms. UNION CARBIDE CORP. 13 April, 1967 [14 April, 1966], No. 17081/67. Heading B5D. An internal former 24 (Figs. 2 and 5) is inserted under one end flap 12 of a cut and openedout bag bottom and the side flaps 16, 18, which have previously been folded outwardly, are folded inwards to overlap by means which hold them down while they are heat sealed. In the form illustrated the side flap 16 is folded in by a roller 28 from which unwinds a flexible curtain 25 clamped at 32. A roller 30 then folds in the side flap 18, unwinding a curtain 26, and the roller 28 retreats before the roller 30 so that the curtain 26 is eventually left holding down both flaps, after the roller 30 has passed right over the bag bottom to the opposite side. The flaps are then welded through the curtain 26 which is formed of glass cloth coated with polytetrafluoroethylene. The internal former 23 may be coated with silicone rubber. |
