Dual contact system for folding in a concertina-fashion

Wrapping device merchandise in single packages, preferably palletized, with a blade (15) extensible tubular or cap, with stirrups (1) to fold and bodies (2) beams by which unfolds in the stirrups (1) folding, the sector of the sheet forming the shell of the side surfaces, and can move the stirrups (1) to fold in the direction (S) horizontally, to transversely extending blade (15) extendible after deployment, and being moveable stirrups (1) folding direction (W) vertically to pull the sheet (15) extensible over the goods in loose packing, preferably so that here the sheet (15) extensible extends along packages, and presenting each body (2) folding devices (5a, 5b) beams with which can be actuated simultaneously, at least temporarily, on the sheet (15) extensible in two zones (Z1, Z2) spaced from one another in the folding direction each comprising body (2) folding at least a first roller (5a) beam, and a second roller (5b) provided below, with reference to the direction of deployment, wherein the roller (5a) beam during operation deployment of the device at its periphery which contacts with the stretchable sheet, has a lower peripheral speed than the roller (5b), so that the sector (16) of the stretch film, which lies between the roller (5a ) and the roller beam (5b), preferably extends and is arranged without overlapping on the corresponding bracket (1) to fold.