GLUE DISTRIBUTION DEVICE AND EMBOSSING-LAMINATION ASSEMBLY PROVIDED THEREWITH

Abstract

 Glue distributing device comprising a glue distributor roller (13) coupled along a generatrix with a transport roller (14) for collecting glue (17) from a doctor chamber (15) comprising a container (16) closed by lateral walls (18) tightly coupled against said transport roller (14), wherein in said container (16) at least one intermediate wall (19) is provided, tightly coupled against the inner surface of the wall of the container (16) and with said transport roller (14), and being translatable parallel to the axis of said roller (14), and wherein means are provided for applying a lubricant (23) on a surface of said transport roller (14) not involved by the glue (17). Embossing-lamination assembly (10) provided with the glue distributing device and comprising at least one embossing roller (11) coupled along a generatrix with said glue distributor roller (13) and along another generatrix with an embossing counter-roller (11').

Description

[0001] The present invention relates to an embossing-lamination assembly of a rewinder machine for rolls of paper, handkerchiefs or depliants or other materials provided with an improved glue distribution device.

[0002] Normally an embossing-lamination assembly for paper comprises at least one embossing roller in steel, at least one embossing counter-roller in rubber, at least one roller for distribution of the glue and at least one transport roller for the glue.

[0003] In more common practice the embossing roller and the respective counter-rollers are normally two and serve to emboss two sheets of paper to be coupled one to the other with possible interposition of other sheets. One or two glue distribution devices are used for the coupling of the sheets.

[0004] Here below, merely for simplicity of description, reference will be made to a single device of distribution of glue on a sheet of embossed paper exiting from a pair of embossing rollers.

[0005] The transport roller, also known as metering roller or anilox roller, takes the glue from a container, also known as doctor chamber, and transfers it to the distributor roller, also known as plate roller, with which it is coupled along a generatrix, which in turn distributes the glue on a sheet of embossed paper.

[0006] The width of the distributor roller has to be smaller than the width of the paper, in order to avoid the glue exiting from the paper material and ending up on the steel embossing roller, soiling it.

[0007] To avoid this disadvantage which, as well as the waste of glue, leads also to the tearing of the paper and in any case to a malfunctioning of the embossing assembly, the replacement is carried out, by means of an overhead crane or machine interior movement systems, of the distributor roller as a function of the width of the paper to be processed. For example if the paper is 2000 mm wide a distributor roller will be mounted with breadth smaller than 2000 mm, typically 1980 mm. If the paper is 3000 mm wide, a distributor roller typically of 2980 mm will be mounted. The 20 mm are necessary for leaving a margin at the sides for avoiding possible slipping, etc.

[0008] This procedure of replacement of the distribution roller as a function of the width of the paper to be processed is disadvantageous both economically due to the high costs of these rollers and due to the complexity of the operation of replacement, which requires considerable machine down times.

[0009] Alternative solutions have been proposed in order to seek to avoid this disadvantage.

[0010] One of these solutions proposed in the patent application EP 2749359 A provides for making axially movable at least the distributor roller or the transport roller, so as to vary the width of coupling between the two rollers as a function of the width of the paper to be processed.

[0011] Such a solution is somewhat complex due to the fact of having to provide means apt to allow the axial movement of the aforesaid rollers and of the accessory components connected to them.

[0012] Another solution proposed in the patent application EP 2025503 A2 provides for giving the doctor chamber lateral walls, placed in contact with the transport roller, movable transversely, so as to reduce, if necessary, the length of the glue container, and therefore the length of the section of transport roller involved by the glue, as a function of the width of the paper.

[0013] The disadvantage of this solution is that the transport roller does not transfer glue onto the end sections of the distributor roller and therefore there is a "dry" contact between the two rollers, due to the absence of glue which performs also a role of lubricant.

[0014] This condition causes premature damage to the distributor roller, or in any case an anomalous temperature due to the surface rubbing.

[0015] The object of the invention is that of eliminating the disadvantages of the prior art. More particularly an object of the invention is that of improving the solution proposed in the aforementioned patent application EP 2025503 A2, avoiding damage to the distributor roller in the zone not involved by the glue.

[0016] Another object of the invention is that of providing such a glue distribution device which is simple and economical to manufacture and at the same time extremely reliable.

[0017] These and other objects of the present invention are achieved by the embossing assembly with glue distribution device as disclosed in the independent claim 1.

[0018] Advantageous embodiments of the invention are disclosed by the dependent claims.

[0019] Substantially an embossing-lamination assembly according to the invention comprises at least one embossing roller coupled along a generatrix with a respective embossing counter-roller for embossing a sheet of paper fed between them, a glue distributor roller coupled along a generatrix with said embossing roller for distributing glue on said sheet of embossed paper, and along another generatrix with a transport roller which collects the glue from a doctor chamber comprising a container closed by lateral walls tightly coupled against said transport roller, wherein at least one wall is provided in said container, tightly coupled against the inner surface of the wall of the container and against said transport roller, said at least one wall being translatable parallel to the axis of said transport roller to vary the width of the chamber of said container of glue according to the width of said sheet of paper, and wherein means are provided, apt to apply a lubricant on the surface of said transport roller not involved by the glue.

[0020] Further features of the invention will be made clearer by the following detailed description, referred to its embodiments purely by way of a non-limiting example and illustrated in the accompanying drawings, wherein:

Figure 1 is a schematic side elevation view showing an embossing assembly of the so-called point-to-point type of a rewinder machine;

Figure 2 is a schematic view of the glue distribution device according to a first embodiment of the invention, taken in the direction of the arrow F of Figure 1;

Figure 3 is a sectioned axonometric view taken along plane III-III of Figure 2;

Figure 4 is a schematic axonometric view of the doctor chamber taken from the side turned towards the transport roller, whereon two different embodiments of the invention are schematised;

Figure 5 shows enlarged and in schematic form the means used in the second embodiment of the invention.

[0021] Referring initially to Figure 1, an embossing-lamination assembly is shown of the so-called point-to-point type, denoted overall by reference numeral 10.

[0022] This assembly comprises a first embossing roller in steel 11 and a counter-roller in rubber 11', between which passes, in order to be embossed, a first sheet of paper V1 along the path indicated in the drawing.

[0023] A second sheet of paper V2 is fed, in order to be embossed, between a second embossing roller in steel 12 and a respective counter-roller in rubber 12'.

[0024] On one of the two sheets, in the case illustrated on the sheet V1, a layer of glue is applied as will be described in greater detail here below, in order to produce the coupling between the two sheets passing in the space between the two rollers 11, 12, obtaining in this way a tape in output denoted by the letter N.

[0025] This type of embossing is called point-to-point in that the two sheets V1 and V2 are coupled between the two rollers 11, 12 with the tips of the respective embossings opposed.

[0026] Obviously the glue distribution device according to the invention is also applicable to so-called "nested" embossing assemblies, i.e. in which the coupling between the two sheets takes place in a random manner and a so-called marrying roller is provided which presses the two sheets against one of the embossing cylinders to produce the coupling thereof.

[0027] Referring again to Figure 1, the device for distribution of glue on the sheet V1 comprises substantially a distributor roller or plate roller 13, a transport roller, or metering roller, or anilox roller 14 and a doctor chamber 15, which will be described in greater detail here below.

[0028] The distributor roller 13 is coupled along two different generatrices with the first embossing roller 11 and, respectively, with the transport roller 14, which, in turn, is in contact with the doctor chamber 15.

[0029] Therefore the glue taken from the doctor chamber 15 by the transport roller 14 is transferred to the distributor roller 13, which applies it to the sheet of paper V1 which passes on the first embossing roller 11.

[0030] Figure 2 shows schematically the glue distribution assembly, comprising the elements previously mentioned, and i.e. the doctor chamber 15, the transport roller 14, the distributor roller 13, and shows also the first embossing roller 11 and the sheet of paper V1 interposed between it and the distributor roller 13, the width of the sheet V1 being smaller than the length of the distributor roller 13.

[0031] The doctor chamber 15 comprises a container substantially with a C shape 16 (visible in Figure 3), apt to contain a fluid glue 17.

[0032] The container 16 is closed by two lateral walls 18, schematised in Figure 2, which are tight against the surface of the transport roller 14.

[0033] In order to adapt the width of the layer of glue to be transferred to the width of the sheet of paper V1 being processed, two movable walls 19 are placed inside the container 16, translatable parallel to themselves in the direction of the axis of the transport roller 14, in order to regulate the working width of containment of the glue 17. One single intermediate movable wall 19 could optionally be provided in order to perform this regulation.

[0034] One of these walls 19 is shown in greater detail in Figure 3 and has at least one perimeter covering in rubber 20 such as to be sealed against the internal walls of the C-shaped container 15 and against the surface of the transport roller 14, in such a way that a translation thereof, with means in themselves known and therefore not shown, in the direction of the arrows shown in Figure 3, varies the width of the opening of dispensing of the glue.

[0035] In the lower part of the doctor chamber 15, with reference to Figure 3, externally to the container 16 a blade scraper 21 is provided, apt to limit the thickness of the layer of glue to be dispensed on the transport roller 14, in order to avoid waste.

[0036] To avoid a dry contact between the transport roller and the distributor roller, at the end sections of these rollers, where the application of glue is not foreseen which, as mentioned, performs also a role of lubricant, according to the invention application of a liquid is provided, which can be water or oil, at these end sections.

[0037] According to a first embodiment of the invention, shown schematically in Figure 2 and, at an illustrative level, also in Figure 4, between the lateral walls 18 and the intermediate walls 19 of the container 16 respective end chambers 22 are formed, which are filled with water 23 or another humidifying/lubricant liquid. In Figure 4 these chambers 22 are indicated with two rectangles placed at the sides of a longer central rectangle indicating the actual doctor chamber for containment of the glue 17.

[0038] In this way on the transport roller 14, as well as the layer of glue 17, of width corresponding to the width of the sheet of paper V1, layers of liquid 23 are also transferred, apt to moisten the end sections of the transport roller 14. Therefore, during the transfer of the glue to the distributor roller 13, and then to the sheet of paper V1, the liquid present on the end sections of the transport roller 14 is transferred onto the end sections of the distributor roller 13, avoiding a dry contact between these rollers, with the disadvantages disclosed previously.

[0039] It has been noted that with this solution, which even though it eliminates the disadvantages arising from a dry contact between the transport roller and the distributor roller, the lubricant liquid was at times transferred to the steel embossing roller 11, soiling it, given that the gap between the distributor roller and the embossing roller is of a few hundredths of a millimetre. Moreover this liquid could also be transferred to the rubber-covered embossing counter-roller 11', deteriorating the features or soiling it. In the case of frequent changes of breadth when returning to produce with wide breadth (after having turned with the narrower one), it was therefore necessary to clean the rubber covering, possibly at that point soiled by glue or something else.
Therefore an alternative embodiment of the invention provides, in place of the lubricant 23 contained in the aforementioned lateral chambers 22, the spray application of a thin layer of glue by means of a series of atomising nozzles 25, carried by respective box-type bodies 26, of length equal to the maximum length of the end sections of the transport cylinder, on which it is foreseen to have to apply the layer of lubricant 23.

[0040] In Figure 4 the series of nozzles 25, or the respective box-type bodies 26, are shown with thick lines above rectangles showing the aforementioned lateral chambers 22.

[0041] In Figure 5 the arrows indicate the inlets of the lubricant liquid, which is then atomised through the nozzles 25, at least some of which can be occluded, in such a way as to be able to regulate the width of the lateral lubricant bands.

[0042] The nozzles 25, by spraying an atomised mixture of air and oil, lubricate slightly the transport roller 14, avoiding a dry contact with the distributor roller 13, yet preventing this lubricant from being transferred to the rollers placed downstream.

[0043] The automation of the atomised spray system provides for the regulation of the system so as never to form a patina of such thickness as to transfer the material to the steel.

[0044] Knowledge of the speed of the machine is sufficient for the correct distribution of the minimal quantity of lubricant and the atomisation makes control elementary, given that the gap between the distributor roller and the embossing roller is in fact of a few hundredths of a millimetre but which are proportionally a measurement controllable also by a rudimentary system of atomisation proportional to the machine speed.

[0045] From what has been disclosed the advantages of the solution proposed by the invention appear clear, which eliminates a dry contact between rollers and the disadvantages which derive therefrom and, in the embodiment with spray nozzles 25 of the lubricant, avoids the possible transfer of this lubricant to the steel embossing roller.

[0046] Naturally the invention is not limited to the particular embodiments previously described and illustrated in the accompanying drawings, but numerous detailed changes may be made thereto, within the reach of the person skilled in the art, without thereby departing from the scope of the invention itself as defined by the appended claims.

Claims

1. Embossing-lamination assembly (10) comprising
at least one embossing roller (11) coupled along a generatrix with a respective embossing counter-roller (11') for embossing a sheet of paper (VI) fed between them,
a glue distributor roller (13) coupled along a first generatrix with said embossing roller (11) to distribute glue (17) on said sheet of embossed paper (V1), and along a second generatrix with a transport roller (14) which collects the glue (17) from a doctor chamber (15) comprising a container (16),
wherein at least one wall (19) is provided, tightly coupled against the inner surface of the wall of the container (16) and with said transport roller (14),
said at least one wall (19) being movable parallel to the axis of said roller (14) to modify the width of the chamber of said container (16) containing said glue (17) based on the width of said sheet of paper (V1),
characterised in that said container (16) is closed by lateral walls (18) coupled tightly against said transport roller (14),
and in that means are provided, apt to apply a lubricant (23) on the surface of said transport roller (14) not involved by the glue (17).

2. Embossing assembly according to claim 1, characterised in that said means for applying a lubricant (23) on the surface of said transport roller (14) are constituted by at least one chamber (22) delimited by said at least one intermediate wall (19) and by a corresponding lateral wall (18), said chamber (22) being apt to contain said lubricant (23).

3. Embossing assembly according to claim 2, wherein said lubricant is water or oil.

4. Embossing assembly according to claim 1, characterised in that said means for applying a lubricant on the surface of the transport roller (14) consist of at least one box-type body (26) comprising a series of nozzles (25) apt to spray said lubricant (23) in the form of an atomised mixture of air and oil such as to form a thin layer of lubricant on said transport roller (14).

5. Embossing assembly according to claim 4, characterised in that at least some of said nozzles (25) are closable such as to vary the width of the lubricant layer sprayed by such nozzles.

6. Embossing assembly according to claim 4 or 5, characterised in that said box-type body (26) carrying the series of nozzles (25) is placed on said container (16) of the doctor chamber (15) adjacent to said at least one lateral chamber (22).

7. Embossing assembly according to any one of the preceding claims, characterised in that said at least one intermediate movable wall (19) has a rubber coating (20) along its perimeter.

8. Embossing assembly according to any one of the preceding claims, characterised in that two intermediate movable walls (19) are provided, each one apt to be positioned substantially at the same distance from a corresponding lateral wall (18), such that said lubricant (23) is applied on end sections of the transport roller (14).

9. Embossing assembly according to any one of the preceding claims, wherein said container (16) of the doctor chamber (15) has a substantially C shape and is provided with a blade scraper element (21) apt to limit the thickness of glue (23) applied on the transport roller (14).

10. Glue distributing device of an embossing-lamination assembly, comprising
a doctor chamber (15) comprising a container (16) closed by lateral walls (18) and containing at least one intermediate wall (19) translatable parallel to the axis of a transport roller (14) which collects the glue (17) from said doctor chamber (15), said lateral walls (18) being tightly coupled against said transport roller (14),
a glue distributor roller (13) which can be coupled along a first generatrix with an embossing roller (11) of an embossing-lamination assembly to distribute glue (17) on said embossed sheet of paper (V1),
means apt to apply a lubricant (23) on the surface of said transport roller (14) not involved by the glue (17),
as defined in any one of the preceding claims.

Drawing