DE4400038A1 - Cutting process to cut short paper rolls from long rolls - Google Patents

Abstract

The cutting process involves cutting at least two short rolls (3) in the paper-cutting machine while the long rolls (ST1, ST2) are in an immobile position during the cutting period of the circular cutter. In the period during which the knife is not cutting, independent feeding and displacement of the two long rolls takes place. One of the rolls is fed in a pusher bed via a separately controlled drive. If there are more than two rolls, it is possible to move the individual ones independently or in groups by means of a separate drive for each one. The drives can also be controlled electronically as a combined unit.

Description

When producing products from hygiene paper in roll form, first of all the parent roll a so-called rod or wrap with the desired number of sheets or meters. Then this rod or wrap is passed through the circular knife machine in a continuous process desired width cut to length. The circular knife plunges so deep into the bar until it is cut the piece to be cut is completely separated from the rod.

Since different roll widths are to be cut in one cutting device, the Roll width optionally set via a computer-controlled feed.

The cutting device usually consists of a rotating knife disc (1) which is mounted eccentrically to the axis of rotation of a crank arm or an orbital disc (2).

During the cut, there must be no relative movement in the rod feed direction between the knife disc ( 1 ) and the paper rod ( 3 ). The paper rod ( 3 ) must only be advanced to the next cutting position in the periods of each orbital disk revolution if there is no engagement of the knife disk ( 1 ).

The time available depends on the knife and orbit disk geometry (diameter), the angular velocity of the orbit disk ( 2 ) and the movement sequences required to move the paper rod forward by the section length (positive acceleration, feed, negative acceleration to a standstill).

To increase the performance of the machine, several - at least two - paper bars can be used (ST1, ST2) are advanced at the same time. However, this increases the Angular range in which the cutting discs engage.

According to the innovation, the paper rods ( 3 ) are individually pushed so that the individual rod (ST1, ST2) only comes to a standstill for the period in which the circular knife ( 1 ) is engaged on the single rod (ST1, ST2).

When two bars ( 3 ) are cut at the same time, the feed movement of bar 1 can thus be initiated again when the circular knife has left the cutting area 1 but is still in the cutting area with bar 2 . The same applies to more than two bars, even with bars arranged one above the other or in different levels.

The bar feed in the so-called pusher bed ( 4 ) has a separate drive ( 5 ) for each bar or bar group ( 3 ). The drive can be controlled independently of each other via an electronic unit so that, depending on the knife position, the maximum local bit angle can be used for the feed into the next cutting position.

The so-called circular knife machines are regularly used in combination with a roll winder and a subsequent packaging machine unit operated. So that the circular knife machine does not have a bottleneck function in this constellation, is a particularly high performance, d. H. a high number of cuts per minute is required.

The innovation described makes it possible to further increase the performance of the circular knife machine and to optimally utilize the round trip times of the circular knife disc ( 1 ) for the rod feed.

Reference list

1 circular knife, knife disc
2 orbital disk
3 bars
4 pusher bed
5 drive for push belt
6 pushers
7 bar in loading position
8 pusher timing belts

Claims (5)

1. Device for minimizing the engagement time of the circular knife ( 1 ) when cutting several paper bars ( 3 ) in a paper cutting machine. 2. Device according to claim 1, characterized in that when cutting at least two paper rods ( 3 ) in paper cutting machines rod ST1 and ST2 are each only in the idle position during the engagement time of the circular knife ( 1 ). 3. Device according to claim 1, characterized in that the time in which there is no engagement of the rotating circular knife ( 1 ) in the paper rod ( 3 ), for each rod track (ST1, ST2) an independent advancement and movement of the individual paper rods takes place or . is possible. 4. The device according to claim 1, characterized in that the feed of individual paper rods ( 3 ) in the respective pusher bed ( 4 ) via a separately controlled and controllable drive. 5. The device according to claim 1, characterized in that with more than two paper rods ( 3 ) an independent feed of the individual rods or a grouped - each group independent - feed is possible by an associated separate drive.