Rewinding machine and rewinding method

A rewinding machine for the production of rolls (R1, R2) of web material wound around winding cores (A1-A4), the machine comprising:

• a winding cradle (3), comprising peripheral winding members (5, 7, 9) of the rolls;
• a feeding path of the web material (N) towards the winding cradle (3);
• an insertion channel (19) for inserting the winding cores (A1-A4) towards the winding cradle, having an entrance (19A) inside which the winding cores are introduced and an exit (19B) toward the winding cradle, the insertion channel being defined between a rolling surface (25) and a continuous flexible member (27), provided with a forward movement;
• an inserter (26) for inserting the winding cores (A1-A4) into the inserting channel (19);
• wherein at the entrance (19A) of the insertion channel (19) a pressing device (45) is arranged, which projects toward the inside of the insertion channel (19) and toward the continuous flexible member (27);
• wherein the pressing device (45) is arranged and configured to press the winding cores entering the insertion channel (19) towards the continuous flexible member (27),
• wherein the continuous flexible member (27) is guided around a severing roller (29) arranged at the entrance (19A) of the feeding channel (19) and around a winding member (5) forming part of the peripheral winding members,
• wherein the continuous flexible member (27) is driven into motion by the severing roller (29) around which the continuous flexible member is guided;
• and
• wherein the severing roller rotates at a peripheral speed controlled so that, at least in a step of inserting a core in the inserting channel, the peripheral speed of the severing roller (29) is lower than the peripheral speed of the winding member (5), the winding member (5) being associated with guide rollers of the continuous flexible member allowing said continuous flexible member to have a feed speed different from the peripheral speed of the winding member (5).

A rewinding machine for the production of rolls (R1, R2) of web material wound around winding cores (A1-A4), the machine comprising:

• a winding cradle (3), comprising peripheral winding members (5, 7, 9) of the rolls;
• a feeding path of the web material (N) towards the winding cradle (3);
• an insertion channel (19) for inserting the winding cores (A1-A4) towards the winding cradle, having an entrance (19A) inside which the winding cores are introduced and an exit (19B) toward the winding cradle, the insertion channel being defined between a rolling surface (25) and a continuous flexible member (27), provided with a forward movement;
• an inserter (26) for inserting the winding cores (A1-A4) into the inserting channel (19);
• wherein at the entrance (19A) of the insertion channel (19) a pressing device (45) is arranged, which projects toward the inside of the insertion channel (19) and toward the continuous flexible member (27);
• wherein the pressing device (45) is arranged and configured to press the winding cores entering the insertion channel (19) towards the continuous flexible member (27),
• wherein the pressing device (45) is resiliently biased in an idle position, in which it projects inside the insertion channel (19), the passage of the winding cores in the insertion channel (19) causing a movement of the pressing device (45) away from the continuous flexible member (27) against an elastic antagonistic force,
• wherein the pressing device (45) comprises a plurality of mutually aligned pressing elements (47), and
• wherein the pressing elements (47) are movable one independently to the other and each of them is provided with at least one resilient biasing member (53) biasing the respective pressing element (47) in said idle position.

A method for producing rolls (R1, R2) of web material wounded around winding cores (A1-A4), comprising:

• providing a winding cradle (3), comprising peripheral roll winding members (5, 7, 9);
• providing a feeding path of the web material (N) towards the winding cradle (3);
• providing an insertion channel (19) for inserting the winding cores towards the winding cradle (3), having an entrance (19A) where the winding cores (A1-A4) are inserted and an exit (19B) towards the winding cradle (3), the insertion channel (19) being defined between a rolling surface (25) and a continuous flexible member (27), provided with a forward movement;
• providing, at the entrance (19A) of the insertion channel (19) for the winding cores, a pressing device (45) projecting towards the inside of the insertion channel (19);
• providing an inserter (26) configured for inserting the winding cores (A1-A4) in the insertion channel (19);
• feeding the web material (N) along the feeding path of the web material towards the winding cradle (3) and winding a first roll (R1) of web material (N) around a first winding core (A1);
• when the first roll (R1) of web material has been completely wound, inserting by means of said inserter (26) a new winding core into the entrance (19A) of the insertion channel (19), between the continuous flexible member (27) and the pressing device (45) so that the new winding core (A1) is pressed toward the continuous flexible member (27) by the pressing device (45), said method further comprising:
• guiding the continuous flexible member (27) around a winding roller (5) forming part of the winding cradle (3) and around a severing roller (29) arranged at the entrance (19A) of the insertion channel (19) for the winding cores;
• at least during the step of inserting the new winding core (A2), rotating the severing roller (29) at a peripheral speed lower than a peripheral speed of the winding roller (5);
• pressing the new winding core by means of the pressing device (45) against the severing roller (29), generating a tension in the web material due to the effect of the difference between the speed of the severing roller (29) and that of the winding roller (5), the tension causing the web material (N) to be severed.