EP0167717B1 - Method of making multilayer paper bags with an echelon closure flap - Google Patents

Description

The invention relates to a method for producing paper bags, in particular multilayer gusseted bags, with a staggered closure flap made of a possibly multilayer paper tube.

Paper bags with staggered flaps are made on relatively expensive machines. Perforation and tear-off devices are required for each individual paper layer. The relatively high level of mechanical engineering is nevertheless undertaken because paper sacks with a staggered cut are technically advantageous, in particular because of the low material consumption.

In contrast, the technical facilities for the production of paper bags with a smooth cut edge are much cheaper. However, the smooth cut has various technical disadvantages, in particular it requires a significantly higher material consumption. Two folds are always necessary for smooth-cut bags. Paper bags with a smooth cut can be made in most paper bag factories because they usually have smooth cut facilities.

The invention has for its object to provide a method for producing paper bags with a staggered closure flap, in which a smooth cutting machine can be used, the material consumption is reduced and the production of a paper bag with only one fold is possible.

The solution according to the invention is achieved in that the paper tube is cut off smoothly, starting from the end edge formed in this way, is slit along the longitudinal outer fold edges in accordance with the length of the flap, then one of the possibly multilayer flaps formed thereby is bent back transversely to the longitudinal direction of the sack and the other flap is cut back becomes.

It has proven to be expedient for the cutting back to be carried out by means of knives which can be brought into engagement from different sides.

The method according to the invention permits the production of a paper sack with a staggered closure flap, using largely smooth-cutting machines. Inexpensive additional equipment is sufficient to turn the smoothly cut sack into a paper sack with a staggered closure flap, i.e. a paper sack that has all the advantages of a relay sack, which can otherwise only be produced with much greater mechanical engineering effort.

• Figur 1 - eine perspektivische Ansicht eines Endes eines Papierschlauchs, der nach dem erfindungsgemäßen Verfahren hergestellt wurde,
• Figur 2 - einen Längsschnitt durch das in Figur 1 dargestellte Papiersackende im flachgelegten Zustand,
• Figur 3 - die Endausbildung des flachgelegten Papiersacks in einer ersten Ausführung mit einer Falz,
• Figur 4 - die Endausbildung des Papiersacks mit zwei Falzungen,
• Figur 5 - einen Längsschnitt durch das glattgeschnittene Ende eines flachgelegten Papiersacks mit seitlich geschlitzten Falzkanten,
• Figur 6 - das Ende des flachgelegten Papiersacks mit einem hochgeklappten Laschenbereich,
• Figur 7 - eine schematische Darstellung des Zurückschneidens der nicht zurückgebogenen Papierlagen.

Preferred embodiments of the invention are described below with reference to the drawing. Show it:

• Figure 1 is a perspective view of one end of a paper tube made by the process of the invention.
• FIG. 2 shows a longitudinal section through the paper bag end shown in FIG. 1 in the flat state,
• Figure 3 - the final formation of the flattened paper bag in a first embodiment with a fold,
• Figure 4 - the final formation of the paper bag with two folds,
• 5 shows a longitudinal section through the smoothly cut end of a flat paper bag with laterally slit fold edges, FIG.
• FIG. 6 - the end of the flat paper sack with a flap area that has been folded up,
• Figure 7 - a schematic representation of the cutting back of the non-bent back paper layers.

The paper bag has an outer layer 1 or 1a. The outer layer 1 is connected to the inner layer 2 via a cross bond 3. The outer layer 1 a opposite the first outer layer 1 is also connected to the inner layer 2 a behind it by means of a transverse bond 3. The two inner gussets are designated by 8, while the outer gussets are designated by 9 and 9a. Along the outer side folds 9, the paper layers 1 and 2 glued together are provided with the longitudinal section 7.

From Figure 2, the final formation of the paper bag shown in Figure 1 can be seen in the flat state. The end edge 4 of the paper layers 1 and 2 glued transversely to one another lies by an amount a in front of the end edge 5 of the paper layers 1 a and 2 a which are connected to one another via a transverse glue 3.

In the embodiment according to FIG. 3, all layers of paper are folded over the transverse fold line 10.

In the end region, on the one hand, the outer sides of the paper layers 1 a lie on top of one another and are glued to one another via the adhesive point 6. The paper layer 2 glued transversely to the first outer layer 1 overlaps the glue point 6 and the inner paper layer 2, which is glued transversely to the first outer layer 1, in turn lies on the outside of the paper layer 1a and is connected to this paper layer via the glue point 6a.

FIG. 4 shows a development of the embodiment according to FIG. 3, in which the second outer layer 1 is additionally folded over twice with the inner layer 2a connected to it. The outer, simply folded ends of the paper layers 1, 2 are glued to the second outer layer 1 via the adhesive point 6a. The inner ends of the paper layers 1 a, 2 a are connected to the ends of the paper layers 1, 2 via a first adhesive point 6 and outward behind the second fold to the second outer layer 1 a via a second adhesive point 6 before the second fold.

FIGS. 5 to 6 show the cutting back process. The paper layers 1 and 2 are up to the area of the counter-holder 11 slotted. They are bent away from the paper layers 2a and 1a into the position according to FIG. 6. This can be done using a suction tape, guide rod or other elements. After folding back, the cutting device consisting of separating knife 12 and counter knife 13 is used to cut off the area of the paper layers 1a and 2a which is dash-dotted in FIG.

Claims (3)

1. Process for producing paper bags, especially multi-layer gusseted bags, with a staggered closing flap, from a paper tube which, if appropriate, is multi-layer (1, 1a; 2, 2a), characterized in that the paper tube is cut off smooth and, starting from the end edge (4) thereby formed, is slit along the longitudinal outer folding edges (9) according to the length of the closing flap, and subsequently one of the tabs thereby formed which, if appropriate, is multi-layered (1, 2), is bent back transversely relative to the longitudinal direction of the bag, and the other tab is cut back.

2. Process according to Claim 1, characterized in that the paper layers (1a, 2a) not bent back are cut back to the end of the slit (7).

3. Process according to Claim 1 or 2, characterized in that cutting back is carried out by means of knives (12 and 13) which can be engaged from different sides of the paper tube.

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