Sheet feed compensator - for intermittent heat sealing/cutting of thermoplastic sheet during bag manufacture

摘要

Sheet movement compensating device for a accommodating cyclic surging of sheet delivery between a continuous processing step (extrusion, calendering, lamination or unrolling from stock) and an intermittent operation (heatsealing and cutting). Particular reference to a compensating unit in which the path between a series of rollers on a pivoted frame can be varied from a series of fixed rollers by oscillating the edge pivotted frame through an arc. Pref. the compensating unit is contained in a portable or travelling housing which can be mounted at various positions on the frame work of a cutting and sealing apparatus (for making thermoplastic bags). Pref. a pair of such units are mounted in parallel over a sheet line and may be moved in unison or independently by a belt drive arrangement. An S-shaped drive system for traversing the compensators by means of a toothed reinforced rubber or synthetic drive belt is claimed. Said to provide a more versatile and/or compact machine than prior art compensator drives.