GB959968A - Improved sealing and severing device for packaging machines - Google Patents

Abstract

959,968. Seaming and cutting non-metallic sheet material. KISAB A.B. Aug. 22, 1962 [Sept. 11, 1961], No. 32335/62. Headings B4B and B5K. A sealing and severing device in packaging machines for effecting sealing and simultaneously therewith severing of packages transversely to the feeding direction of the packages by means of two rotating rolls resiliently pressed against each other and against opposite sides of the package sheet material and having surfaces designed to form narrow, mutually co-operating sealing zones parallel to the axes of the rolls, one of two co-operating zones being provided with a knife and the other with a striking bar having a counter surface perpendicular to the knife, both members extending all along the length of the zones, is characterized in that the knives and/or the striking bars are slidably fitted in radial slots in the rolls and are provided with end portions protruding from the end walls of the rolls, which end portions, at the severing moment move into engagement with and are pressed radially outwards by two cam surfaces which are movable in a plane perpendicular to the tangential plane of the rolls against the urge of resilient members. In the embodiment shown, lower roll 1 is rotatably journalled in two fixed arms 4 whilst the upper roll 2 is rotatably journalled in two lever arms 6 pivoted on frame 3 by shaft 8. Also on shaft 8 are pivoted two further arms 9, each of which supports a roller 11 rotatably journalled on a shaft 10. The rolls 1, 2 are formed with surfaces which form mutually coacting sealing zones 12, 13 and 14, 15 in which zones the rolls have radial slots 16, 17, 18, 19. Striking bars 20 are fixedly mounted in slots 16, 18 and knives 21 are slidably fitted in slots 17, 19 and have end portions protruding from the end wall of the roll 2. The free ends of arms 6 and 9 are resiliently attached to the arms 4 by means of rods 22 and 23 and springs 24, 25 adjustable by nuts 26, 27. As rolls 1, 2 are rotated, units 28 to be packaged in sealable sheet wrapper material are advanced between rolls 1, 2. The radius of rolls 1, 2 and the number of sealing zones are so adapted that seals are obtained intermediate the package units. At every sealing operation the end portions of a knife 21 pass under the rolls 11 so that the knife is pressed outwards and into engagement with the corresponding striking bar and is pressed thereagainst by spring 25. The bars 20 are sunk below the surface so that the sheet material is clamped during the cutting operation. If desired, it is possible to give the knife a tilting motion during the cutting operation. It is also possible for the rolls to have a reciprocating motion the rolls being parted during the backward motion.