Folding apparatus for a continuous web

A folding apparatus for a continuous web being fed in a plant for production of absorbent hygiene articles to be folded into a “V” or “U” shape in a first longitudinal portion and in a second longitudinal portion according to a longitudinal folding line parallel to a feeding line of the continuous web, said folding apparatus comprising:

• a folding section comprising:
• a contact unit for the continuous web extending along the feeding line of the continuous web and defining the longitudinal folding line;
• a first guide having a first sliding surface for the continuous web and a second guide having a second sliding surface for the continuous web, the first guide and the second guide being positioned on opposite sides of the contact unit,
• wherein the first sliding surface and the second sliding surface of extend in a helical fashion,
• wherein the first sliding surface and the second sliding surface extend along said feeding line,
• wherein the first sliding surface and the second sliding surface each have a respective infeed section, where the web is not folded, and a respective outfeed section, positioned downstream of the respective infeed section according to a web feeding direction, where the continuous web is folded in two and has the first longitudinal portion and the second longitudinal portion set at an angle to each other,
• wherein the infeed sections of the first and the second sliding surfaces are substantially coplanar,
• wherein the outfeed section of the first sliding surface and the outfeed section of the second sliding surface are transversal to the respective infeed sections and at least partly converging in the web feeding direction;
• wherein at least one of said first guide or said second guide is movable about an axis of rotation transversal to the feeding line,
• an adjusting system for a relative position of longitudinal edges of the continuous web once the continuous web has been folded, said adjusting system comprising:
• at least one position sensor for checking a relative position of the longitudinal edges of the continuous web once the continuous web has been folded,
• at least one actuator connected to the at least one of said first guide or said second guide for moving the at least one of said first guide or said second guide about the axis of rotation,
• a computerized control unit in communication with the at least one position sensor and said at least one actuator and configured for moving, via said at least one actuator, said at least one of said first guide or said second guide about the axis of rotation depending on a significant piece of information about the relative position of the longitudinal edges as received from the at least one position sensor.