| 摘要 |
1,001,016. Sealing bag necks. W. R. GRACE & CO. Dec.18, 1963 [March 21, 1963], No. 50083/63. Heading B8C. [Also in Division B5] The gathered end of a bag of heat-shrinkable material is sealed by first heating it, without applying appreciable pressure, and then cooling the heated mass while applying sealing pressure. In the machine illustrated, the neck of a filled bag is gathered by clamps 52, 53 (Fig. 1) drawn together by light springs and carried by an endless conveyer 48. Flanges 66, 67 (Fig. 5) on the clamps are then carried into heating bars 79, 80 (Fig. 1), and subsequently through converging bars 81, 82 which cool the gathered neck and apply pressure to seal it. The pressure should be sufficient to reduce the thickness of the neck at least 10%. The clamps may print or emboss the bag neck. The bars 81, 82 may be continuous with the bars 79, 80, or guiding rollers 34, 35, or a funnel-shaped guide, may assist in directing the gathered bag neck into the cooling bars 81, 82. The gathered neck may be trimmed at 101 before it is heated. The bag is preferably evacuated, before the neck is heated, by a suction nozzle which moves with the bag and is withdrawn immediately before the trimmer 101. The bags are subsequently carried through a heat-shrinking oven. |
