| 摘要 |
1469671 Making bags; seaming ROBERT BOSCH GmbH 17 Oct 1974 [19 Oct 1973] 44988/74 Headings B5D and B5K A method of producing bags from a longitudinally folded thermoplastic plastics foil web comprises advancing the folded web to a first welding station whereat the folded web is transversely welded over only a portion or portions of its width, advancing the thus welded web to a further welding station or stations whereat, after hardening of the first welded portion or portions, the folded web is transversely welded over the remaining portion or portions of its width, and advancing the welded, folded web to a cutting device for severing a bag from a chain of bags joined at transverse weld seams 10, 11. The welding stations may produce single welds or double welds 12 to 17 as shown. Each seam 10, 11 may comprise three or more welded regions produced at two or more welding stations. For example, the web may be welded in its central region at the first welding station and at its marginal regions at a second welding station, or vice-versa. An apparatus, Fig. 2 (not shown), for performing the method may comprise a folding triangle (20) and guide (21) for longitudinally folding the web, spaced pairs of welding jaws (23, 24), pairs of cooling jaws (25, 26) located downstream of the associated welding jaws, and feed rollers (22) located downstream of the welding and cooling jaws and upstream of a web cutting device (29). |
