Abstract

An apparatus for forming packaging material into a tubular form includes angularly disposed forming rollers for causing the longitudinal edges of the packaging material to overlap one another so that they can be sealed together. To prevent the packaging material tube from being trapped between adjacent rollers, each of the forming rollers can be provided with one straight roller edge and one chamfered roller edge. The rollers are positioned such that the chamfered roller edge of one forming roller cooperates with the straight roller edge of the adjacent roller, thereby defining a nip directed generally tangentially to an adjacent portion of the packaging material tube. Alternatively, to achieve the same objective, two different types of forming rollers can be employed, one type in which both roller edges are straight and another type in which both roller edges are chamfered. In this latter case, the two types of rollers are alternated with one another.