Rotary jaw assembly for packaging machines

摘要

A rotating-jaw assembly (1) for packaging machines comprises two rotating elements (21, 22; 31, 32) that are able to rotate in opposite directions about respective axes of rotation (X4, X5). Each of the aforesaid rotating elements carries at least one closing jaw (7, 8), which during the movement of rotation of the respective rotating element (21, 22, 31, 32) performs an orbital movement about the respective axis of rotation (X4, X5). The jaws (7, 8) are thus able to co-operate in opposed pairs in a relationship of closing with the successive portions of the wrapping material containing the articles being packaged, which is fed through the two units (2, 3) of which the rotating-jaw assembly 1 is made up. At least in the unit (3) situated in the lower position, i.e., in a position intermediate between the jaws (8), there is set a supporting structure having a general tile-like conformation, comprising three rolling bodies, such as three rollers (13), which are also mounted on the respective rotating element (21, 22) in a position that is generically set alongside the jaws (8). An actuation mechanism (15 to 20) causes, during rotation of the unit (3), the aforesaid rollers (13) to rotate in the same direction as the direction of rotation of the rotating-jaw unit so as to be able to exert, on the wrapping material that is riding on them, not only an action of support but also an action of drawing along, the foregoing in order to keep the wrapping material in proper conditions of tensioning, so facilitating the formation of areas for closing of the ends, particularly as regards bellows-shaped areas.