| 摘要 |
1,233,224. Bag making; seaming non-metallic sheet material. WINDMOLLER & HOLSCHER. 13 Aug., 1968 [18 Aug., 1967], No. 38639/68. Headings B5D and B5K. Machine for heat-sealing continuously moving workpieces of plastics film e.g. tube sections for making bags, has a plurality of heatsealing jaw sets secured to endless conveyer chains, each heat-sealing jaw set being arranged to be energized in dependence on the machine cycle and to be de-energized by means of a timing element after a predetermined interval of time. Tubular material is cut into bag lengths S, each of which is fed at position 37 into a pair of retaining and heat-sealing jaws 8-37, mounted on conveyer chains 2, 2<SP>1</SP>. Heat-sealing begins when the workpiece enters on the lower run of the conveyer. The retaining and sealing jaws are guided by rollers in suitable guide rails and are closed by a pair 38, 38<SP>1</SP> of a series of pairs of rails, acting on rollers 89, 89<SP>1</SP> to close the heat-sealing jaws 86, 91 (Figs. 3-5, not shown). The rails 38, 38<SP>1</SP> are pivotally mounted on levers 58, 59; 60, 61 &c. and acted upon by a respective piston-cylinder unit 63-72 through a corresponding beam 82. These units are controlled by respective cams 145-154 driven by the machine which cams also operate time relays in the heating circuits, to interrupt the heating current after a pre-set time interval. Current is conveyed to the heating jaws through current collectors 101, 101<SP>1</SP> from a common neutral bar 102 and a respective bus-bar 48 of a series of bus-bars 48-57. After the heat sealing the heating jaws are separated through release of the rails 38, 38<SP>1</SP> by the piston-cylinder unit. Subsequently the retaining means are opened and the bag deposited on a delivery container. The arrangement is such that each corresponding cam, piston-cylinder unit, pair of rails and current collectors control one of a number (10 as shown) of heat-sealing jaw sets along the lower run of the conveyer and as each set leaves said control a further set is introduced at the beginning of the run, thus enabling, say 10 out of say 30, heat-sealing jaws to be operative at the same time. |
