GB2154923A - Severing sheets from a web - Google Patents

Abstract

When a set of paper sheets, arranged so that their ends over- or under-lap, are laminated to a continuous film it is not possible subsequently to sever individual laminated sheets from the resulting web with a conventional blade. Accordingly, one or more cuts are made in the film lamination only, these cuts being parallel to the longitudinal axis of web 10 and in the area if overlap, e.g. using rotary discs 28 near one edge of the web; the weakened web is then severed by pairs of rollers, 30,36 applying tension. This arrangement is particularly appropriate in the production of laminated book jackets. <IMAGE>

Description

SPECIFICATION Improvements in or relating to coated paper production apparatus The present invention concerns improvements in or relating to paper production apparatus, especially but not exclusively to apparatus for separating sheets of paper from a continuous film which has been laminated on to a series of sheets arranged, generally, in end-to-end relationship.

A decorative or protective film of clear plastics material is often applied to printed sheets to be used, for example, as book jackets. The laminating operation is carried out on a machine which feeds a series of separate sheets to a laminating station where the sheets, with an edge portion of one overlapping or underlapping its neighbour, has a continuous film of clear plastics material laminated thereto. It will be realised therefore that the product of the machine is a roll of paper sheets arranged in end-to-end overlapping relationship coated on one side with a continuous film of plastics.

A web of sheets of this nature will be referred to hereinafter as "laminated sheets of the type defined".

It is then necessary to return the sheets to their separate condition for further processing and in view of the automated nature of this further processing it is essential that the size of the sheets remains unaltered. It will be realised therefore that a simple guillotine operation to separate one sheet from its neighbour cannot take place as this would result in at least one part of the sheet being lost.

It is an object of the present invention to provide a machine which separates the sheets from a continuous film lamination without altering the size of the sheets.

According to the present invention there is provided a sheet separator for laminated sheets of the type defined, comprising feed means for a web of laminated sheets, blade means for making at least one cut in only the film lamination in a direction substantially parallel to the longitudinal axis of the web at an area of overlapped sheets and, downstream of said blade arrangement, a tensioning arrangement for applying tension to the web whereby the lamination rips along the overlapped edge of a sheet.

Preferably the blade means comprises a plurality of disc blades arranged in side-byside relationship and driven about an axis transverse to the longitudinal axis of the web.

Preferably the blade means are mounted for fine adjustment towards and away from a web support roller thereunder.

Preferably between a supply drum for the web and the blade means there are provided additional guide rollers, for example an anticurl bar.

Preferably immediately downstream of the blade means there is provided a pair of pressure rollers defining a nip through which the web is fed. Conveyor means are provided for carrying the web and separated sheets downstream of the pressure rollers and at a distance spaced from the pressure rollers by an amount greater than the length of a separate sheet, there is provided a pair of separating rollers defining a nip therebetween, the separating rollers being driven at a speed greater than the pressure rollers whereby they exert tension on the laminating film of the web intermediate the pressure and separating rollers.

To assist in the separating process there is provided a sheet deflection wheel upstream of the separating rollers to laterally distort the web and assist in the ripping of the film.

Preferably the spacing of the deflection wheel from the pressure rollers is slightly less than the length of a sheet to be separated.

Preferably an adjustable sheet collection tray is located at the discharge from the conveyor means.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 shows a diagrammatic plan of a sheet separating apparatus; and Figure 2 shows a diagrammatic sectional elevation of the apparatus.

A web 10 of laminated paper sheets arranged in end-to-end overlapping or underlapping relationship with the continuous lamination film maintaining the otherwise separate paper sheets in position is stored on a drum 1 2 which is freely rotatably mounted at the inlet of the machine. The web is guided over an anti-curl bar 14 and under a first guide roller 1 6 prior to moving over a second guide roller 1 8 arranged at a higher level than the first guide roller 1 6 whereby the web is deflected over the roller 1 8. A blade bar 20 extends across the web above the second guide roller 1 8 and its mounting means 22 include vertical adjustment means for raising or lowering the cutter bar away from or towards the second guide roller.The cutter bar is driven by a motor 25 by way of a transmission belt 26 and carries a cutting head 28 which is mounted for rotation with the bar and comprises a plurality of knife-edge cutting discs spaced apart by a small distance along the head. It will be realised that by operating the blade height adjustment the cutting discs can be made to cut slashes in the laminate film only parallel to the longitudinal axis of the web at those areas of the web of increased thickness, i.e. at the overlapped or underlapped edges of adjacent sheets. This results in an area of weakness in the lamination film at one edge of the web 10, but not in damage to the sheet and gives an opportunity for a sheet separating arrangement ar ranged downstream of the cutter bar to separate one laminated sheet from its neighbour.

The separating arrangement includes a first pair of rollers 30 urged towards each other such that they exert a pressure on the web passing therethrough. At least one of the rollers of this first pair is driven by a second drive motor 32 by way of a drive belt 34.

Spaced downstream of the pressure rollers are a pair of separating rollers 36 at least one of which is driven by a motor 38 by way of a drive belt 40. The separating rollers 36 are spaced from the pressure rollers 30 by a distance greater than the length of the sheet to be separated and arranged on the side of the separating rollers 36 nearest to the pressure rollers 30 there is provided a sheet deflecting wheel 42 the axis of rotation of which is angled to the longitudinal axis of the web. The deflection wheel 42 is spaced from the pressure rollers 30 by a distance which is less than the length of a sheet to be separated and consequently it will be realised that the line of intended separation is located between the deflecting wheel 42 and the separating rollers 36.The speed of rotation of the separating'rollers 36 is greater than that of the pressure rollers 30 so that a tension is applied to the web and this tension, in combination with the distortion at the edge of the sheet caused by the deflecting wheel 42, gives rise to a transverse ripping action through the laminating film which is encouraged by the areas of weakness provided at the edge of the film by the cuts made by the cutting discs 28.

As a result, when the film is ripped across the edge of one sheet, the downstream sheet is pulled away from the upstream sheet by the separating rollers and after being returned to its original orientation by correcting rollers 44 downstream of the separating rollers 36, the separated sheet is transported to an adjustable sheet collection tray 46 at the outlet from the machine by an arrangement of continuous conveyor belts 48 the upper run of which extends from the outlet from the pressure rollers 30 the outlet from the machine with an interruption guided by two pairs of S-rollers 50 around the lower separating roller 36.

To accommodate sheets of varying sizes the assembly comprising the separating rollers 36, its drive arrangement 38, 40, the deflecting wheel 42, the correcting rollers 44 and the conveyor belt S-rollers 50 are all mounted for movement as an assembly towards or away from the pressure rollers 30.

The pressure exerted by the pressure rollers 30 and by the separating rollers 36 is adjustable by means of a cam arrangement at one end of the rollers.

Various modifications can be made without departing from the scope of the invention, for example the cutting drum 28 may include only one cutting disc, although more than one closely spaced cutting discs are preferable. The arrangement of rollers may be modified in any convenient manner and sheet transportation means other than conveyor belts may be provided.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to whether or not particular emphasis has been placed thereon.

Claims (11)

1. A sheet separator for laminated sheets of the type defined, comprising feed means for a web of laminated sheets, blade means for making at least one cut in only the film lamination in a direction substantially parallel to the longitudinally axis of the web at an area of overlapped sheets, downstream of said blade arrangement, a tensioning arrangement for applying tension to the web whereby the lamination rips along the overlapped edge of a sheet.

2. A separator as claimed in claim 1, in which the blade means comprises a plurality of disc blades arranged in side-by-side relationship and driven about an axis transverse to the longitudinal axis of the web.

3. A separator as claimed in claim 2, in which the blade means are mounted for fine adjustment towards and away from a web support roller thereunder.

4. A separator as claimed in any one of claims 1 to 3, in which between a supply drum for the web and the blade means there are provided additional guide rollers, for example an anti-curl bar.

5. A separator as claimed in any one of claims 1 to 4, in which immediately downstream of the blade means there is provided a pair of pressure rollers defining a nip through which the web is fed.

6. A separator as claimed in claim 5, in which conveyor means are provided for carrying the web and separated sheets downstream of the pressure rollers and at a distance spaced from the pressure rollers by an amount greater than the length of a separate sheet, there is provided a pair of separating rollers defining a nip therebetween, the separating rollers being driven at a speed greater than the pressure rollers whereby they exert tension on the laminating film of the web intermediate the pressure and separating rollers.

7. A separator as claimed in claim 6, in which there is provided a sheet deflection wheel upstream of the separating rollers to laterally distort the web and assist in the ripping of the film.

8. A separator as claimed in claim 7, in which the spacing of the deflection wheel from the pressure rollers is slightly less than the length of a sheet to be separated.

9. A separator as claimed in any one of claims 6 to 8, in which an adjustable sheet collection tray is located at the discharge from the conveyor means.

1 0. A sheet separator for laminated sheets of the type defined, substantially as hereinbefore described with reference to the accompanying drawings.

11. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.