| 摘要 |
1,015,181. Valve bags. MASCHINENFABRIK WINDMOLLER & HOLSCHER. Sept. 29, 1961 [Oct. 6, 1960], No. 35354/61. Heading B8K. [Also in Division B5] An insert valve in a multiply paper or like bag comprises two superposed sheets, one of paper, the other of plastics, the plastics sheet protruding inwardly beyond the paper in the bag 10 as to form flexible closure lips. To produce the insert, paper and plastics web 1, 2 respectively are drawn from rolls 24, 26, the web 1 passing round the roll 26 and being fed, slightly offset transversely, by rolls 29, 30 to perforating means 31, 32. Both webs are perforated simultaneously, but in order to offset the perforations longitudinally, one web passes over an adjustable roll 2 so that the plastics line of perforations trails that of the paper (by a distance b, as shown). The webs advance to a folding wheel 46 where elements 45, 59 engage the leading and (on a line 6, as shown) to turn the projecting area of the paper and a strip 7 of the plastics material on to the latter. At the same time, the greater speed of the wheel 46 relative to the web feed causes tearing along the foremost perforations. The web may be checked by a brake 48 during tearing. Elements 60-63 apply adhesive and the insert is laid on the open bottom of the bag with the fold 6 outermost and the portion 12 of the plastics sheet against what will be the inside of the bag. The bottom flaps are then folded in and secured, the flap 19 being folded first. |
