Cutting – With product handling means – Including means to form or hold pile of product pieces
Reexamination Certificate
1999-06-18
2001-05-22
Rada, Rinaldi I. (Department: 3724)
Cutting
With product handling means
Including means to form or hold pile of product pieces
C083S099000, C083S155000, C083S161000, C083S949000
Reexamination Certificate
active
06234053
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns a label stacker for a rotary punching apparatus having a punching roll with cutting edges and a smooth counter-pressure roll for, during operation, jointly punching labels out of a thin web conveyed between the rolls while these are rotating in different directions.
BACKGROUND
Labels are normally printed on thin webs of plastic film or paper of thicknesses down to 0.01 mm. The thin labels leave the rotary punching apparatus with a speed of e.g. 5.0 m/sec. With such high speeds, it has turned out to be difficult to control the label flow from the rotary punching apparatus and get the labels stacked correctly in the stacking area. The label stacker will furthermore have a considerable linear extent, because the rotary punching apparatus with the above speed sends out a label flow of a length of 50 m to the label stacker each second.
An object of the invention is to provide a label stacker of the kind mentioned in the opening paragraph, which has a compact structure, and which can effectively control the label flow from the rotary punching apparatus and be certain to stack the labels in orderly stacks in the stacking area.
SUMMARY OF THE INVENTION
According to the present invention, the label stacker includes a belt conveyor with at least one endless conveyor belt that, during operation, is driven with a lower speed than the circumferential speed of the rolls about a first rotating roll at the discharge end of the rolls and a second rotating roll at the stacking area. In this way, the labels in the label flow will be made to overlap each other on the conveyor and, therefore, can be dimensioned with a correspondingly smaller linear extent. The reduced conveying speed furthermore means that the label flow can be properly controlled to the stacking area, and the labels are therefore certain to be stacked in orderly stacks. The stacking is facilitated, because the labels have been made to overlap each other already on the belt. This formation only needs to be pushed together to form the finished stack.
The rotary punching apparatus puts, with great regularity, each of the punched labels down in a specific place in the formation of labels on the conveyor belt. In order to avoid that the finished stack of labels becomes disarranged, it is important that each label remains exactly in its place in the formation all the way to the final stacking operation.
To obtain this, the conveyor belt, which typically can be made of an elastomer, can be perforated and subjected to a differential pressure for sticking the labels to the belt by means of a low pressure along the underside of the belt.
The negative pressure can, in an advantageous embodiment, be made by enclosing the belt with an open body connected to a vacuum source and by letting the belt part of the conveyor run close to the opening of the body.
The labels are thin and light. The air resistance they encounter during conveyance to the stacking area is therefore likely to blow them up and tear them off the conveyor belt or disarrange the formation. To avoid this, an air duct can, according to the invention, be placed above the belt part of the conveyor. Air flows through this air duct with a greater speed than the conveying speed in the conveyance direction and serves for keeping the labels down. Therefore, the air flow has the useful effect of preventing the labels from getting up and being disarranged or torn off, because the labels meet air resistance during transportation on the belt conveyor.
The air flow can, in an advantageous embodiment, be coming from a second air duct connected to a compressed-air source, and which, at the first rotating roll, pass into the first air duct. In the transition of the two ducts, there can furthermore be placed a number of reversing blades for, already from the beginning, ensuring that the air flow is blown evenly and regularly over the formation of labels on the conveyor belt and will therefore not, in itself, disarrange the formation.
The air speed through the first air duct can be regulated in the longitudinal direction by letting the upper wall of the first air duct be pivotally hinged to the second air duct at the transition from the first air duct to the second. The upper wall can, e.g., be put in such that the cross section of the first air duct is gradually decreasing in the conveyance direction, whereby the air speed is proportionally increased. Thereby, the labels are advantageously pressed even harder down on the conveyor belt until finally being safely blown into, e.g., a case for stacking the labels. At the same time, there is compensated for the amount of air drawn through the belt.
The geometry in the area between the discharge end of the rolls and the belt part of the conveyor means that an open gap will necessarily be made here into which the labels can fall down, or which can cause them to be placed in a disadvantageous way on the conveyor belt. To eliminate this disadvantage, a bridge can be placed extending between the counter-pressure roll and the start of the belt part of the conveyor, so that the labels are also supported entirely in this area. The top side of the bridge can advantageously be smooth so that the labels do not encounter any resistance of importance when they are sliding across the bridge.
The belt conveyor can have just one belt, and in this case, the labels will be conveyed at the same speed all the way. However, when the belt conveyor has several successively placed belts running with speeds which are decreasing with every belt, the label flow will be slown proportionally down before the final stacking operation which furthermore can take place safely and effectively, as the labels in the formation, now already in advance, are pushed almost together and therefore only need to be pushed together a short distance to cover each other in the finished label stack.
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Olsen Arne
Olsen Steen
Flores-Saánchez Omar
Interket Trykkeri A/S
Pennie & Edmonds LLP
Rada Rinaldi I.
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