Roller for the Transformation of Tape Material, In Particular for Paper Material

Abstract

A roller (10) for converting tape material comprises a cylindrical pressure surface (11) defined by a coating element (21) made of resilient material of predefined hardness applied over a plurality of resilient annular pressure elements (15) made of elastic deformable material arranged axially side by side, so as to obtain an overall elastic yielding of the roller (10) independent from the superficial elastic yielding.

Claims

1.-8. (canceled)

9. A roller for the transformation of material in tape of the type used in cooperation with at least one further roller or other contrast surface so that the tape material is interposed between the side surface of the roller and the side surface of the further roller or the contrast surface, wherein the roller comprises at least one pressure surface made of an elastically deformable material externally associated in a rotatably fixed manner to a cylindrical body mounted to rotate around its axis, wherein the side pressure surface is defined by a coating element made of a resilient material applied on an outer surface of a plurality of resilient annular pressure elements arranged side by side in an axial direction, each of the resilient annular pressure elements including an annular body made of an elastic deformable material, comprising an outer ring, an inner ring mounted on the cylindrical body, and a plurality of connecting arms arranged inclined with respect to a radial direction and dimensioned for elastically connecting the inner ring with the outer ring.

10. The roller for the transformation of tape material according to claim 9, wherein the coating element is made of a resilient material having a hardness greater than 70 ShA.

11. The roller for the transformation of tape material according to claim 9, wherein the coating element is made of a resilient material having a hardness between 30 ShA and 70 ShA.

12. The roller for the transformation of tape material according to claim 9, wherein the coating element is associated with the roller by vulcanization,

13. The roller for the transformation of tape material according to claim 9, wherein the connecting arms are arranged inclined with respect to the radial direction.

14. The roller for the transformation of tape material according to claim 9, wherein each of the resilient annular pressure elements is mounted angularly staggered with respect to adjacent resilient annular pressure elements so as to achieve a substantially uniform elastic yielding of the pressure surface.

15. The roller for the transformation of paper tape material according to claim 9, wherein the cylindrical body is made of a lightweight material including any of one of aluminum or carbon fiber.

16. The roller for the transformation of paper tape material according to claim 9, wherein the resilient annular pressure elements are made of an elastically deformable material having a hardness greater than 70 ShA.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other advantages and characteristics associated with the roller of the present invention, will become, however, more easily understood through the illustration of non-limiting examplifing embodiments, as described below with the aid of the enclosed drawings, in which:

[0013] FIG. 1 shows a schematic side sectional view of an axial end portion of a roller according to the present invention;

[0014] FIG. 2 is a sectional view taken on the line II-II of FIG. 1;

[0015] FIG. 3 is a schematic sectional view taken along the line III-Ill of FIG. 2;

[0016] FIG. 4 is a schematic view of a machine for producing paper products with two embossed and laminated layers according to the NESTED method comprising two rollers according to the present invention;

[0017] FIG. 5 is an enlarged view of the detail “X” of FIG. 4;

[0018] FIG. 6 is an enlarged view of the detail “Y” of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] With reference to FIGS. 1 to 3, a roller 10, according to the present invention, is shown, which comprises a cylindrical side pressure surface 11 in this embodiment.

[0020] The roller 10 comprises a cylindrical tubular, 12, extending axially for the entire axial length of the roller 10, mounted coaxially, in rotatably fixed mode, outside two revolving end support bodies, 13 (of which is shown in FIG. 3 only the one on the left end of the roller 10). In the embodiment of FIG. 3 each revolving end support body 13 is composed of a tubular portion, 13a, to the outer surface of which is associated the cylindrical tubular 12 and a solid shaft portion, 13b, one end of which protrudes axially from the cylindrical tubular 12 and is arranged to be rotatably supported by support members, N, through the interposition of rolling bearings, B.

[0021] Externally, in a radial direction, a plurality of resilient annular pressure elements 15 are mounted to the cylindrical tubular 12, arranged side by side in an axial direction, coaxially mounted on the outer surface of the cylindrical tubular 12 in a rotatably fixed manner.

[0022] Each resilient annular pressure element 15 is made of a single body of elastically deformable material of hardness preferably greater than 70 ShA and comprises an outer pressure ring 16, an inner ring 18, mounted on the cylindrical tubular 12 of the cylindrical body and a plurality of connecting arms, 19, arranged and dimensioned for elastically connecting the inner ring 18 with the outer pressure ring 16.

[0023] The connecting arms 19 are arranged inclined with respect to the radial direction and form separation septa between a plurality of axial cavities, 20, made between the inner ring 18 and the outer pressure ring. Together with the characteristics of the elastically deformable material with which the resilient annular pressure element 15 is made, the dimensions of the cavities 20 and of the connecting arms 19 and the inclination of the latter define the properties of the overall elastic yielding of the portion of the roller 10 defined by the annular pressure element 15 itself.

[0024] In fact, because of the material of which they are made and of their sizing, the connecting arms 19 tend to bend in the plane orthogonal to the axis of the roller 10, with consequent deformation in the same plane of the outer pressure ring 16 which assumes a radially corrugated shape but does not deform in the axial direction nor it moves in this direction with respect to the inner ring 18.

[0025] According to a preferred embodiment, the resilient annular pressure elements 15 are made of elastomeric material of suitable hardness, as mentioned above preferably of 70 ShA, and their deformability is defined by suitably dimensioning the length, thickness and inclination of the relative connecting arms 19. Alternatively, the resilient annular pressure elements are made of materials having a high elasticity module but with a much greater hardness, such as for example the harmonic steel, and the desired deformability is provided by providing a substantially lower thickness of the relative connecting arms 19 and of the outer pressure ring 16 with respect to the embodiments in which the annular pressure elements 15 are made of elastomer.

[0026] As can be seen from the schematic section of FIG. 3, all the annular pressure elements 15 are identical to each other, but each resilient annular pressure element 15 is mounted angularly offset with respect to the adjacent ones of the same entity so as to provide a cylindrical lateral surface of the roller 10 with substantially uniform overall elasticity.

[0027] Externally to the outer ring 16 of the annular pressure elements 15 there is a coating element 21, made of resilient material, of suitable thickness, which extends to substantially cover the entire lateral surface of the roller 10, and whose outer surface constitutes the pressure surface 11 of the roller 10. The coating element 21 is applied around the annular pressure elements 15 directly by vulcanization of a rubbery material, or by gluing or by other techniques.

[0028] With reference to FIG. 4, the roller 10 above described is advantageously used in a process for the realization of two-ply embossed paper with NESTED pairing type in which a first, V1, and a second, V2, ply of tissue paper are dragged by a group of rollers which perform the embossing, the pairing and the bonding of the two plies. More specifically, each ply crosses a relative deflection roller, R1, R2, a relative contrast roller, C1, C2, and a relative engraving roller, G1, G2, provided with an embossed surface pattern, the interaction among which performs the NESTED pairing of the two plies V1 and V2. In correspondence of a first engraving roller G1 is present a group of glue application comprising a glue tank, S, in which catches a roller pad, T, which transfers the glue to an applicator roller, A, which applies the glue on the surface of the first ply V1. Before leaving the first engraving roll G1 the two paired paper plies are pressed one against the other by a pressing roller, P, which acts against the first engraving roll G1 itself to allow the glue to fasten together the two plies before exiting the machinery through a further deflection roller, R3.

[0029] In the group described above a first contrast roller 10′ and the pressing roller 10 are rollers according to the present invention.

[0030] As shown in the detail Y of FIG. 6, the “nip” between the engraving roller G1 and the contrast roller 10′, equal to the value d1, is high due to the high overall elastic yielding of the contrast roller 10′ conferred by the presence of the annular pressure elements 15. At the same time the engraving of the decorative pattern in the paper takes place effectively thanks to the high superficial yielding of the contrast roller 10′ conferred by the coating element 21′, which has advantageously hardness comprised between 30 ShA and 70 ShA and thickness suitable for embossing the decorative pattern in the paper tape product to be treated. In this case the high “nip” that is obtained allows a longer time of treatment of the veil which allows the resilient coating to deform obtaining a better embossing height compared to a traditional rubber roller.

[0031] As shown in the detail “X” of FIG. 5, the “nip” between the engraving roller G1 and the pressing roller 10, equal to the value d2, is also high thanks to the high overall elastic yielding of the contrast roller 10 conferred by the presence of the annular pressure elements 15. At the same time the re-embossing effect is completely avoided, thanks to an extremely reduced elastic surface yielding conferred by the high hardness of the resilient material with which the coating element 21 is formed which defines the pressure surface 11, advantageously superior to 70 ShA. Moreover, the coating element 21 provides a side pressure surface 11 free of discontinuity without the necessity of providing a very precise side-by-side arrangement of the annular pressure elements 15.

[0032] Moreover, in both cases, thanks to the lightness of the roller and to the elastic yielding of the resilient annular pressure elements 15, the pressure with which it is necessary to press the rollers 10, 10′ against the engraving roller G1 to obtain a large nip and a good drag of the roller itself is extremely modest compared to that required with conventional rollers. Thanks to this, the cylindrical body on which the annular pressure elements 15 are mounted can be of extremely simple and lightweight construction because it may not have the characteristics of robustness and flexural rigidity with which the conventional pressure rollers must be equipped in order to withstand the high pressures of contact.

[0033] It is certainly easy to understand that the application examples described above are merely illustrative of the peculiarity and versatility of a roller according to the present invention whose use can be advantageous whenever it is desirable a roll having a continuous side surface and with an overall elastic yielding and a superficial yielding of the roller completely independent from one another, without significant increase in production costs. For example, a roller according to the present invention can advantageously be used not only in applications in which it cooperates with a further roller, but also in association with flat surfaces, such as for example belt conveyors ones.

[0034] Obviously many variations to the roller structure of the invention described above by way of example are within the reach of a technician of the sector without this having to employ any inventive activity, such as for example the possibility of realizing a roller according to the invention in which the surface of pressure 11 is not cylindrical but concave, with a barrel, or with another arbitrary profile, or that the structure described is applied only on an axial portion of a roll which is overall longer than the portion which presents the structure according to the present invention.

[0035] In fact, the above made description of specific embodiments is useful to illustrate the invention core concept, in such a way that experts in the field may implement it modifying and adapting the above said embodiments to the various applications; such adaptations and modifications will therefore be considered as equivalent to the exemplified embodiments. It is understood that the phraseology or numbering used have purely descriptive and aid purposes for understanding the inventive concept and therefore are not limiting.