Abstract: A machine for the production of weldable plastic film bags from a strip reel, and for the filling of the said bags, comprises means of supporting and unwinding a first strip reel (B.sub.1); means of supporting a second reserve strip reel (B.sub.2); and means (41, 49) of cutting and welding the strip (N), to automatically make the join between the trailing end of the strip being unwound from the first reel (B.sub.1) and the leading end of the strip on the second reel (B.sub.2) when the first reel is about to be used up. In order to bring the strip on reel (B.sub.1) into phase with the strip on reel (B.sub.2), there are provided means (5, 7, 9) of delimiting a predetermined length of the path of the strip between the means of forming, filling and sealing the bags and the means (41, 49) of cutting and welding the strip; a first reference (151) down-line from the means of welding and cutting the strip; and a second reference (153) for the strip from the second reel.

Abstract: For the continuous formation of bags for containing bulk materials--in the form of granules, powders and the like--the end of the web (EN), from a new bobbin (BA) in readiness, is laid, with the surface to be welded on the outside, around a welding bar (18) carried by a movable element (12), and the bar (18) is positioned opposite a counterbar (20), along which the web (N) being exhausted from the previous bobbin (B) runs; bar and counterbar are brought close to one another to carry out transverse welding and cutting, in such a manner that a superimposed and welded edge (BS) emerges transversely from the continuous web thus joined, from the surface opposite that of welding. (FIG.