Method and apparatus for winding up coreless and soft-core rolls of film materials

An apparatus for winding up coreless and soft-core rolls of film materials, according to which a film is made to advance along a drawing path, comprising a drawing drum conformed to corrugate the plastic film as it is being wound onto a roll, said apparatus comprising:

• first and second drawing units for the film, spaced apart along said drawing path, each drawing unit being provided with a respective electric control motor;
• a signal generator connected to each control motor;
• the second drawing unit comprising a corrugating drum having a plurality of longitudinally extending slots;
• means for generating an air jet to urge the film against the corrugating drum to at least partially penetrate the same film into the slots of the corrugating drum;
• means for forming a floating loop of film between said first and second drawing units, and sensing means for detecting the floating loop;
• the apparatus also comprising an electronic control unit, said control unit being conformed and programmable to control the feeding of the film by the first drawing unit at a first speed, and the drawing of the film by the second drawing unit at a second speed lower than the first speed, in relation to control signals received from said signal generators and from said sensing means for controlling the floating loop.