Rewinding machine and method for controlling the speed of the motors in a rewinding machine

A method for rewinding a web material, the method comprising the steps of:

• unwinding a primary reel of web material comprising at least one ply of tissue paper by at least one unwinding member controlled by an unwinding motor;
• winding the web material in a winding station by at least one winding motor and forming at least one secondary reel in the winding station;
• detecting a parameter function of a tension of the web material along a path between the at least one unwinding member and the winding station;
• controlling a difference between a speed of the winding motor and of the unwinding motor as a function of said parameter.

A start-stop tissue paper rewinding machine for unwinding primary reels of a tissue paper web material and rewinding the web material in secondary reels through successive winding cycles spaced by stops for replacement of the secondary reels with new winding cores, the machine comprising:

• a winding station with winding members operated by at least one winding motor;
• at least two unwinders, each of the at least two unwinders comprising at least a respective unwinding member operated by at least one respective unwinding motor;
• for each unwinder, at least one respective guide roller along a feed path of the web material unwound from a respective one of the unwinders;
• at least one respective load sensor associated with each guide roller, the at least one respective load sensor being configured to detect a parameter proportional to a tension of the respective web material guided around the guide roller;
• and
• a control unit configured to modulate a difference in speed between the winding members and the unwinding member of each unwinder as a function of a signal from the at least one respective load sensor.

A method for rewinding tissue paper web materials, from primary reels to secondary reels, through successive winding cycles spaced by stops for replacement of the secondary reels with new winding cores, the method comprising the steps of:

• unwinding a first primary reel of tissue paper web material comprising at least one ply of tissue paper by a first unwinding member controlled by a first unwinding motor;
• unwinding a second primary reel of tissue paper web material comprising at least one ply of tissue paper by a second unwinding member controlled by a second unwinding motor;
• winding the first web material and the second web material in a winding station by at least one winding motor and forming at least one secondary reel in the winding station, wherein a plurality of secondary reels are produced in a sequence of start-stop cycles by winding the first web material from the first primary reel and the second web material from the second primary reel;
• detecting a parameter function of a tension of the first web material and of the second web material along a respective path between the first unwinding member and the second unwinding member and the winding station;
• and
• controlling a difference between a speed of the winding motor and of each unwinding motor as a function of said parameter.