Machine for cutting to size rolls of predefined length from logs with a greater length

Machine for cutting to size rolls (R) with a defined length (L2) from logs having a greater length (L1),comprising:

• a first conveyor belt (20) which can be driven so as to convey a log (1) advancing in a longitudinal direction (X-X);
• a programming and control device (500) for controlling and commanding operating drives and performing the necessary synchronization for correct management of the machine cycle;
• a pair (30) of second conveyor belts, i.e. a bottom belt (31) and a top belt (32) respectively, which are parallel to each other and arranged downstream of the first belt (21) in the longitudinal direction (X-X);
• a cutting blade (2), downstream of second conveyor belts (30), which can be rotationally driven and which is fixed in the longitudinal direction and movable in the vertical direction (Z-Z);
• a third conveyor belt (60) for conveying finished rolls (R) towards the machine outlet;
• a first photocell (81) connected to the programming and control device (500) and arranged upstream of the second conveyor belts (30) in the longitudinal direction (X-X), for detecting the passage of the rear end (1b) of a log (1) being machined and sending a respective signal to the programming and control device (500);
• wherein the programming and control device (500) is configured to command feeding of a new log to be machined to the first conveyor belt (20), depending on said signal emitted by the first photocell (81);
• and wherein the programming and control device (500) is configured to control driving in the feeding direction of the first belt (20) at a first speed (V20) and of the second belts (31,32) with respective speeds (V20, VI30), such as to cause contact of the front end (1a) of a new log (1) to be machined with the rear end (1b) of the log preceding it along the longitudinal feeding path through the machine.

Process for cutting to size rolls (R) with a defined length (L2) from logs having a greater length (L1), comprising the following steps:

• supplying a first log (1) to be machined to a first conveyor belt (20) for conveying logs along a longitudinal direction (X-X);
• conveying the first log (1) by means of said first belt (20) to a pair (30) of second conveyor belts, i.e. bottom belt (31) and top belt (32) respectively, which are parallel to each other and arranged downstream of the first belt (21) in the longitudinal direction (X-X);
• taking-up of the log (1) by the second conveyor belts (30) and conveying thereof to a cutting blade (2) which can be rotationally driven and which is fixed in the longitudinal direction and movable in the vertical direction (Z-Z);
• cutting a leading trim (RT) of predefined length (L3) from the log (1) being machined by means of the cutting blade (2);
• controlled feeding of the log (1) being machined to the cutting blade (2) by means of the second conveyor belts (30), with sequential cutting of rolls (R) of predefined length (L2);
• detecting passage of the rear end (1b) of a log (1) being machined by means of a first photocell (81) arranged upstream of the second belts (30) in the longitudinal direction (X-X) and connected to a programming device (500) for controlling and commanding the various operating drives and performing the necessary synchronization for correct management of the process;
• sending a respective signal for detection of passage of the rear end (1b) of the log (1) being machined to the programming and control device (500);
• supplying a new log to be machined to the first conveyor belt (20), commanded by the control device (500) depending on said signal emitted by the first photocell (81);
• driving the first belt (20) at a first speed (V20) in the feeding direction and of the second belts (31, 32) at respective speeds (V20, VI30) such as to cause contact of the front end (1a) of the new log (1) to be machined with the rear end (1b) of the log preceding it along the longitudinal feeding path through the machine;
• conveying cut rolls (R) towards the machine outlet.