GB2048223A

GB2048223A - Apparatus for Feeding a Multi- layer Web Conveyed Without Interfacial Slip

Info

Publication number: GB2048223A
Application number: GB8014297A
Authority: GB
Original assignee: Jagenberg AG; Jagenberg Werke AG
Current assignee: Jagenberg AG; Jagenberg Werke AG
Priority date: 1979-05-08
Filing date: 1980-04-30
Publication date: 1980-12-10
Also published as: DE2918449C2; DE2918449A1; ES491268A0; ES8101011A1; GB2048223B; IT8021783A0; IT1130340B

Abstract

Apparatus for feeding a multi-layer paper web, without slip at interface of layers, comprises upper and lower endless conveyor belts 23, 24, arranged to travel over guide rollers. The conveyor belts form a passageway therebetween for the web and in the region of this passageway being supported on their rear sides by support tables (27, 28). The support tables have flat, non-resilient support surfaces arranged parallel to the plane in which the web is guided. <IMAGE>

Description

SPECIFICATION Drawing Part for a Multi-layer Web of Material to be Conveyed The invention relates to a drawing part for a multilayer web of material to be conveyed, which in particular is located in front of a transverse cutting part and consists of upper and lower conveyor belts travelling over guide rollers, which conveyor belts form a passageway therebetween for the web of material and are supported in the region of this passageway on their rear sides by support tables.

It is known occurrence that when conveying a multilayer material web, the various layers of the material web are displaced with respect to each other to a greater or lesser extent on passing through the drawing part. If the drawing part is followed by a transverse cutter, then this displacement results in differences of format, which are known generally as a so called stair-cut effect.

In order to keep the displacement of the individual layers as slight as possible, various measures have been implemented. In a known machine of the aforementioned type, the drawing part comprises special rollers, in which a compressible air cushion is provided between the roll body and a resilient roll shell. The roll body is connected to the roll shell by way of interengaging teeth so that it is unable to move in the tangential direction but is able to move in the radial direction. This special construction of the rollers allows the rollers to be pressed flat in the roll gap (German Patent Specification 1 786 341). The degree of displacement is less in a drawing part of the aforementioned type, in which the support tables are formed by air cushions.The intended effect of the air cushions is that the material webs are engaged with gentle and uniform pressure between the conveyor belts.

On the one hand, a drawing part of this type requires substantially higher constructional expenditure than the drawing part consisting of a pair of rollers and on the other hand, the reduction of the displacement of the individual layers of the material web achieved in comparison with the drawing part consisting of rollers no longer satisfies current requirements.

The object of the invention is to provide a drawing part with which the displacement of the individual layers resulting when conveying a multi-layer material web is less in comparison with that occurring in known drawing parts.

This object is achieved according to the invention due to the fact that the support tables comprise flat, non-resilient support surfaces arranged parallel to the plane in which the web is guided. On account of the special construction of the support tables, although the drawing part according to the invention has a simpler construction as compared with a drawing part with support tables constructed as air cushions, the degree of displacement of the individual layers is less. It was found that it is not the resilient support with uniform pressure which is critical for reduced displacement, but the flat surfaces of the support tables defined exactly as regards their position.If the multilayer material web is guided between air cushions, then whilst compressing the air cushion with a uniform application of pressure, it can be deflected, but with non-resilient support surfaces, a deflection of this type is not possible, whereby the local pressure can increase. Accordingly, the drawing part according to the invention operates according to a principle other than that of the known drawing part.

In order to facilitate the introduction of the material web into the passageway between the support tables, the non-resilient support surfaces may be preceded by further divergent, nonresilient support surfaces.

Although, on account of the construction of the tables, the drawing part according to the invention has a simpler construction as compared with tables constructed as air cushions, better results are achieved as regards the displacement of the individual layers. It was found that the gentle, uniform pressure in the region of the drawing part, considered as necessary in the known drawing part with air cushions, not only is unnecessary, but leads to a higher degree of displacement of the individual layers. This result is surprising since with a pair of rollers as the drawing part with a slightly resilient covering, poorer results were obtained than with a drawing part with belts and a resilient support table.

The invention is described in detail hereafter with reference to the drawing illustrating one embodiment.

The drawing shown an apparatus for longitudinal and transverse cutting, diagrammatically and in side view.

A multi-layer paper web 1 is supplied by way of a guide roller 2 to a longitudinal cutting part 3, 4. The material web 1 passes over suspended strips 5 arranged below the plane in which the web is guided, into a drawing part 6, from there over suspended strips 7 likewise arranged below the plane in which the web is guided, to a transverse cutting part 8,9. Instead of suspended strips 5,7, other web-supply members, for example conveyor belts or guide plates may be provided.

In a conventional drawing part, the individual layers are displaced with respect to each other in the drawing part so that the central layer precedes the outer layers. This has the result that in the adjoining transverse cutting part 8,9, the individual layers have different lengths. With the drawing part according to the invention, the displacement of the individual layers with respect to each other is reduced to a value which satisfies current requirements.

The drawing part consists of a lower and upper part, which are constructed in the same way. The lower part is arranged to be stationary, whereas the upper part held in a frame 10 can be swung upwards about a pivot 12 by means of a lifting member 11. Each part consists of a conveyor belt 23,24 travelling over guide rollers 13 to 20 and a drive roller 21,22 as well as of a support table 25,26.

Each support table 25,26 comprises a flat, non-resilient support surface 27,28 which is parallel to the plane in which the web is guided and at the inlet side comprises an inclined support surface 29,30 adjoining the flat support surface 27,28.

The multi-layer material web entering the passageway formed by the support tables 25,26 is engaged and thus compressed by the preceding diverging support surfaces 29,30, without the support surfaces 29,30 yielding at right angles to the plane in whilch the web is guided. In the adjoining region of the flat support surfaces 27,28, the support surfaces likewise do not yield.

The material web emerging from the drawing part then enters the transverse cutting part 8,9 virtually without displacement of the individual layers.

Claims

1. Drawing means for a multi-layer web of material to be conveyed, for example a paper web, said means comprising upper and lower conveyor belts arranged to travel over guide rollers and forming a passageway therebetween for the web of material and in the region of this passageway being supported on their rear sides by support tables having flat, non-resilient support surfaces arranged parallel to the plane in which the web is guided.

2. Drawing means as claimed in claim 1, wherein the non-resilient support surfaces are preceded by further diverging, non-resilient support surfaces.

3. Drawing means for a multi-layer web of material to be conveyed, for example a paper web, susbstantially as herein described with reference to and as illustrated in the accompanying drawing.