| 摘要 |
1475007 Making plastic bags; seaming non- metallic sheet material UNIFLEX Inc 17 Dec 1974 [16 April 1974] 54528/74 Headings B5D and B5K An attachment, for a bag forming machine 54, Fig. 3, of the type in which a longitudinally folded web W, is advanced continuously to a compensating roll assembly 60 and then intermittently while bag forming operations are performed thereon, comprises a supporting frame 10, Fig. 1, having means for supporting a supply roll of heat-sealable web material; means 66 for continuously folding the web longitudinally and guiding it to the machine 54; a plurality of guide rollers 76, 78, 80, 84, 86, 88, 90, 92 located on the frame to establish a loop-like path for the web as it passes from the supply roll to the folding means; edge capping means 82 on the frame for providing an additional thickness of material at one edge of the web in a first part of the loop-like path; heating means 116 movably supported on the frame and operable along a second part of said path to fuse the additional thickness to the web; and means for withdrawing the heating means from the web upon interruption of web movement along said path. As described heat-sealable material from rolls 24, 26 is fed over rollers 76, 78 to form a double thickness web which is then fed via roller 80 to the edge-capping means 82, which comprises a pair of plates 100, 102, Fig. 5 having angled slots 108. The edge or edges of the web, and/or edge-capping strips fed from rolls 40 Fig. 1 are folded by passage through the slots 108, Fig. 5, to provide additional thicknesses of material at the web edge(s). The plates 100, 102 are adjustable laterally by hand screws 106 to cater for different widths of web. The web then passes over rollers 84, 86, Fig. 1, to the heating means 116; 118, Fig. 5, each including heated wires 138 which fuse the thicknesses of web material together. Each heating meads includes plates 128 with tubes 140 for coolant, the plates being mounted on rods 130 interconnected by pinions 132. The pinions can be moved by rams 134 to move the heating elements from the operative positions shown to the inoperative dashed-line positions. The heating elements are adjustable laterally by screws 126. The web is then folded by passage over rods 66, Fig. 3 and is advanced continuously by a driven capstan 58 to compensating rolls 60 whereafter it is fed intermittently through the rest of the bag-forming machine 54. Should the intermittent feed be interrupted a bar 62 carrying the rollers 60 falls to operate a switch 144 which causes the drive to the capstan 58 to be halted, and sends a signal to a control unit 146 which operates the rams 134 to move the heating elements away from the now stationary web. |
