Method and apparatus for enhanced cutter throughput using an exit motion profile
View Patent ↗A method and apparatus are for decelerating a sheet of paper in a paper-cutting system. The sheet of paper is cut using a cutter, and the sheet is then accepted into a take-away nip. The take-away nip is operated at an initial rate in order to move the sheet of paper away from the cutter at an initial speed. The take-away nip is then operated at a rate decreasing to a final rate, in order to decelerate the sheet of paper to a final speed by the time the sheet of paper exits the take-away nip. The take-away nip is subsequently operated at the initial rate again, prior to accepting another sheet of paper at the initial speed.
1. A method for accelerating and decelerating sheets of paper in a paper-cutting system, the method comprising:
cutting a web of paper using a cutter, when the paper is substantially stopped, to form a sheet of paper having dimensions exceeding at least one threshold, the sheet comprising a leading end and a tail end;
securing the leading end of the sheet of paper in a nip;
operating the nip to move the sheet of paper away from the cutter;
decelerating the nip based on the threshold in order to slow the sheet of paper to a final speed at least by the time the tail end of the sheet of paper exits the nip;
repeating operation of the nip in order to move further sheets of paper away from the cutter;
wherein the final speed of each sheet of paper is suitable for processing the sheet in a downstream processing component;
wherein an average speed of each sheet of paper, while it is secured in the nip, is greater than the final speed; and
wherein the average speed is high enough to avoid contact between each sheet of paper and the web, but low enough to prevent the leading end of each sheet of paper from contacting a downstream sheet.
2. The method of claim 1 , wherein the at least one threshold is a ratio of sheet length divided by sheet width.
3. The method of claim 2 wherein the final speed depends upon said ratio of sheet length divided by sheet width.
4. The method of claim 1 , wherein the downstream processing component comprises a right angle turn device,
wherein, when the sheet of paper has the final speed, the nip has a corresponding final rate equal to a substantially constant rate of a downstream nip, and
wherein the downstream nip precedes the turn of the right angle turn device.
5. The method of claim 4 wherein the final rate of the nip substantially equals the constant rate of the downstream nip.
6. An apparatus for accelerating and decelerating sheets of paper in a paper-cutting system, the apparatus comprising:
a cutter configured to cut a web of paper when the paper is substantially stopped, in order to form a sheet of paper having dimensions exceeding at least one threshold, the sheet comprising a leading end and a tail end;
a nip configured to secure the leading end of the sheet of paper;
a motor and motor controller configured to operate the nip to move the sheet of paper away from the cutter, and further configured to decelerate the nip based on the threshold in order to slow the sheet of paper to a final speed at least by the time the tail end of the sheet of paper exits the nip, and furthermore configured to repeat operation of the nip in order to move further sheets of paper away from the cutter;
wherein the final speed of each sheet of paper is suitable for processing the sheet in a downstream processing component wherein an average speed of each sheet of paper, while it is secured in the nip, is greater than the final speed, and
wherein the average speed is high enough to avoid contact between each sheet of paper and the web, but low enough to prevent the leading end of each sheet of paper from contacting a downstream sheet.
7. The apparatus of claim 6 , wherein the at least one threshold is a ratio of sheet length divided by sheet width.
8. The apparatus of claim 7 wherein the final speed depends upon said ratio of sheet length divided by sheet width.
9. The apparatus of claim 6 , wherein the downstream processing component comprises a right angle turn device,
wherein, when the sheet of paper has the final speed, the nip has a corresponding final rate equal to a substantially constant rate of a downstream nip, and
wherein the downstream nip precedes the turn of the right angle turn device.
10. The apparatus of claim 9 , wherein the final rate of the nip substantially equals the constant rate of the downstream nip.