Patent Grant
11479010
The invention relates to machines for paper converting, particularly but not exclusively for converting tissue paper for the production of toilet paper, kitchen towels and similar products. More specifically, the invention relates to embossing devices and embossing methods.
In the continuous web manufacturing industry, such as webs of tissue paper or the like, for example to produce rolls of toilet paper, paper napkins, rolls of kitchen towels and similar, machines are used to emboss cellulose web materials, by means of which the originally smooth material is subjected to a permanent deformation resulting in the formation of embossed protrusions. Two or more plies of web material are usually embossed separately from one another and then bonded, using glue, with different mutual arrangements of the protuberances produced by embossing on the one or more plies. Generally speaking, the embossed plies are bonded using so-called tip-to-tip technology, or using a so-called ‘nested’ technology, or using variants of these two base technologies.
The embossing patterns for one or the other of the plies forming the embossed tissue paper are changed with a certain frequency, both in order to obtain a variation in the outer appearance of the product, and for technical reasons, for example because certain patterns are more suitable for the production of toilet paper while others are preferable for the production of kitchen towels, or vice-versa. Therefore, when switching from the production of one type of item to another it may be necessary or useful to change one or more embossing rollers on the embossing device. Furthermore, embossing patterns must be selected as a function of the embossing technique used, for example some patterns used for tip-to-tip embossing may not be suitable for nested embossing, and vice-versa. Embossing devices exist, with which it is possible to produce both types of item, and in this case there is a further need to change the embossing rollers.
Embossing devices also exist, which are fitted with a plurality of interchangeable embossing rollers, forming a sort of storage unit. For example, U.S. Pat. No. 6,688,366 discloses an embossing device with a plurality of pairs of interchangeable embossing rollers, fitted onto a rotating support, or onto sliding supports that can move from a standing-by position to a working position. This embossing device is complex and not very efficient, since it does not permit the replacement of single rollers, but rather only the replacement of pairs of rollers.
The production of tissue paper may sometimes be carried out in small batches, meaning that in some cases, replacement of the embossing rollers may also be quite frequent.
A need, therefore, exists for embossing devices, wherein the embossing rollers can be changed quickly, by means of simple, easily-automated operations.
According to one aspect, in order to fully or partially overcome the drawbacks of the prior art, an embossing device is provided with at least a first embossing roller, a second embossing roller, a first pressure roller co-acting with the first embossing roller and a second pressure roller co-acting with the second embossing roller, which rollers are arranged in an embossing area. The embossing device also comprises a substantially vertical storage unit, in which spare embossing rollers can be stored, for replacing one or the other of the working embossing rollers. The vertical development of the storage unit, wherein the seats for the embossing rollers are mutually superposed, allows easier access to the embossing rollers and to the seats thereof for replacement.
In the present context the term “substantially vertical”, in reference to the development of the embossing roller storage unit, refers to a storage unit in which the various seats for the embossing rollers are located at different levels, i.e. at different heights from a base, for example from the base of the embossing device. In this sense, the seats do not have to be exactly superposed one above the other in a vertical line, but can be superposed, i.e. at different heights, but staggered horizontally, for example with a step-like arrangement. According to advantageous embodiments, the storage unit may be at a distance from and laterally aside the embossing area, where the embossing rollers temporarily in use are installed. In this way, maintenance and control of the embossing device are made easier. Furthermore, the embossing rollers waiting in the storage unit are less likely to get dirty due to the dust and other detritus present in the embossing area. Furthermore the total capacity of the storage unit has virtually no limits or constraints in terms of available space.
In some embodiments, for instance, the storage unit may be placed upstream of the embossing area with respect to the direction in which the plies are fed to the embossing device. In this way, the storage unit may be part of a bearing structure, on which idler rollers or guide rollers for the plies of tissue paper fed to the embossing area may be mounted.
In advantageous embodiments, between the storage unit and the sides supporting the working embossing rollers, a passage for equipment, or personnel responsible for the management and control of the embossing device, can be provided.
For instance, the storage unit may be mounted on a base, on which are also mounted sides that support the rollers in the embossing area, thereby creating a single structure.
In advantageous embodiments, the embossing device may be provided with a transfer device that (on request and according to the various production needs, based on the set-up that the embossing device has to take) transfers the required embossing rollers to the machine and the unused rollers to the storage unit, and vice-versa. The transfer device may be movable along crossbeams arranged at a height higher than the embossing area where the working embossing rollers and the respective pressure rollers are located, together with the other organs defining the ply routes. The presence of a transfer device can simplify roller replacement operations.
The crossbeams on which the transfer device can move may extend from the storage unit to the sides supporting the rollers in the embossing area. The crossbeams may advantageously be arranged at a height from the base of the embossing device such as to allow the transit of personnel responsible for managing the embossing device. The crossbeams may be used as a support for guide rollers for the plies of tissue paper.
In practice, the storage unit, the crossbeams and the sides supporting the rollers in the embossing area may form a sort of gantry structure, which can be mounted on a common base of the embossing device.
The transfer device may be movable according to two translation axes, preferably orthogonal to one another, for example a vertical axis and a horizontal axis. Advantageously, in some embodiments, movement along the two axes can be numerically controlled by means of suitable servo-motors. In this way, it is possible to have the replacement of the embossing rollers controlled by a programmable central control unit. The operator only needs to set the type of material to be manufactured, and the transfer device automatically selects and replaces the rollers. However, it is not excluded that in simpler and less expensive embodiments, these operations will be carried out manually, i.e. with manual control of movements of the transfer device.
The transfer device may comprise a pair of arms ending with engagement hooks for engaging the embossing rollers. The engagement hooks may co-act with annular grooves idly mounted on supporting and rotation journals of the embossing rollers, to facilitate manipulation of the rollers. For example, at each one of the two ends of the supporting and rotation journals of each embossing roller a respective sleeve may be mounted, idly supported on the respective journal of the embossing roller, said sleeve being provided with an annular groove, which may be provided with bevels to facilitate engagement by the hooks of the transfer device.
In some embodiments, the storage unit may comprise seats for cliché rollers, or glue applicator rollers, of a glue dispenser. Where present, the transfer device can be controlled and arranged to exchange the glue applicator roller in the embossing area with a glue applicator roller located in the storage unit. In this way it becomes simpler to adapt the embossing device to the different paper formats that it may be required to produce. Indeed, plies of tissue paper may have different widths and the glue applicator roller used each time preferably has an axial length roughly equal to or slightly less than the width of the tissue paper. The term axial length refers to the size in an axial direction of the working cylindrical surface of the glue applicator roller. Sometimes, it is also necessary to use glue applicator rollers with particular surface patterns, so as to distribute the glue in a particular pattern. In this case, too, replacement of the glue applicator roller using the transfer device and provision of glue applicator rollers standing-by in the storage unit can be useful to simplify and speed up the operation of setting-up the embossing device.
According to another aspect, the invention also concerns a method for replacing rollers in an embossing device, comprising the following steps:
Further according to the method, the passage extends vertically from a base of the embossing device to crossbeams supporting movement of the transfer device and extends laterally between the storage unit and the embossing area for enabling transit of the passage by personnel responsible for management and control of the embossing device after carrying out said stopping operation of the embossing device and before said starting operation of the embossing device again
The roller may be an embossing roller, or a glue applicator roller, or a cliché roller, of a glue dispenser.
The steps for transferring the roller from the embossing area to the storage unit and vice-versa can be performed using a transfer device.
An example of an embodiment of an embossing device and its various possible modes of use will be described in greater detail below, with reference to the accompanying drawings, wherein:
With initial reference to
Embossing rollers and pressure rollers are arranged between the two opposing sides 3C, 3D. The number of embossing rollers associated with an embossing device 1 may vary, so as to be able to set up the embossing device 1 in different ways, using a sub-set of available embossing rollers, for example in order to produce embossed web material with a different structure and configuration.
In general, in some embodiments of the embossing device disclosed herein, it is possible to change quickly the paths of the plies processed by the embossing device, for example to switch from the production of a tip-to-tip-type web material to a material bonded using the nested technique, or so-called DESL (Double Embossing Single Lamination), or even a so-called DERL (Double Embossing Random Lamination) product. In a product manufactured according to tip-to-tip bonding, two or more plies are embossed separately from one another and then bonded between two embossing rollers by pressing therebetween embossing protuberances belonging to the two embossing rollers. In a product made using the nested, DESL or DERL technique, the two plies are embossed separately and then bonded between one of the embossing rollers and a lamination roller. Depending on the mutual position between the embossed protrusions of the two plies, a distinction is made between nested, DESL and DERL. In general, in every case one of the two plies is removed from the embossing roller that embossed it and is placed on the other of the two embossing rollers on top of the other ply. In this way, both plies pass through an embossing nip formed between one of the two embossing rollers and the lamination roller.
As will become clear from the following description, a first advantage of the embodiment of an embossing device according to the present disclosure, is that it can facilitate the change of configuration from a configuration for the production for example of an embossed and tip-to-tip laminated multi-ply material, to an embossed multi-ply product laminated using the nested, DERL or DESL technique. The operations to be performed on the embossing device described below, which involve a change to the path of the plies as they pass through the embossing device, are substantially simpler and quicker than those required in prior art machines, which as known require not only roller replacement but also structural changes and the addition of other parts to the machine such as rubber-coated rollers, “bowed” rollers, arms for embossing rollers, etc. Another type of configuration change is associated with the type of pattern on the surface of the rollers, without needing to change the path of the plies inside the machine. This happens, for example, when one wants to switch from a DESL or nested embossing to a different type of DESL or nested embossing, changing the embossing pattern, but not the path of the plies in the embossing device. The embossing device disclosed herein facilitates this type of change.
There will be identified below a first embossing roller, a second embossing roller and a third embossing roller inside the embossing device 1, between the sides 3C and 3D. These first, second and third embossing rollers can change from one setup (or configuration) to another setup of the embossing device 1, in the sense that they can be replaced with other embossing rollers temporarily waiting in a storage unit for interchangeable rollers. Therefore, depending upon how many rollers are mounted on the embossing device 1, the first embossing roller, the second embossing roller or the third embossing roller may be different and variable as a function of the configuration and setup of the embossing device 1.
With particular reference to
Each embossing roller 5, 7, 9 is provided with embossing protuberances, schematically shown in the detailed enlargements shown in
During operation of the embossing device 1, the first embossing roller 5 provided with the first embossing protuberances 5P rotates around a rotation axis 5A and co-acts with a first pressure roller 11, rotating around a rotation axis 11A substantially parallel with the rotation axis 5A. The pressure roller 11 may be coated with a layer of elastically yielding material, schematically indicated by reference number 11B. The elastically yielding layer 11B may be made of rubber, synthetic rubber, or any other yielding material, preferably an elastically yielding material.
Between the first embossing roller 5 and the first pressure roller 11 a first embossing nip 13 is formed, through which the path of a first ply V1, for example a ply of cellulose fiber, such as a ply of tissue paper, extends. The ply V1 is embossed in the first embossing nip 13 due to the effect of the mutual pressure exerted between the first embossing roller 5 and the first pressure roller 11. As a result of said pressure, the protuberances 5P of the first embossing roller 5 penetrate into the thickness of the elastically yielding coating 11B covering the cylindrical surface of the first pressure roller 11.
Similarly, the second embossing roller 7, which rotates about a rotation axis 7A, substantially parallel to rotation axis 5A of the first embossing roller 5, co-acts with a second pressure roller 15 which, like the first pressure roller 11, may be coated with a layer of elastically yielding material 15B, for example rubber. The second pressure roller 15 rotates about a rotation axis 15A substantially parallel to rotation axis 7A of the second embossing roller 7. Between the second embossing roller 7 and the second pressure roller 15 a second embossing nip 17 is formed. A path for a second ply of cellulose material V2 may extend through the second embossing nip 17.
As will become clear from the following description, in some operating modes, both plies V1 and V2 are not necessarily present in the embossing device 1. For example, in some operating modes, the ply V2 may be omitted.
Furthermore, with reference to the above and to the description below, it must be understood that the plies may in turn be formed from two or more layers and may be delivered from a single reel or by several reels of cellulose material.
When present, the ply V2 is embossed, in other words it is permanently deformed in the embossing nip 17 due to the mutual pressure exerted between the second embossing roller 7 and the second pressure roller 15, said pressure causing penetration of the embossing protuberances 7P of the second embossing roller 7 into the elastically yielding material forming the coating 15B of the second embossing roller 15.
The third embossing roller 9 co-acts with a third pressure roller 19, rotating about a rotation axis 19A substantially parallel to a rotation axis 9A, about which the third embossing roller 9 rotates, and to the rotation axes 11A, 5A, 7A and 15A mentioned above.
The third pressure roller 19 may be coated with an elastically yielding material which forms a coating 19B, similar to coating 11B and coating 15B of the first pressure roller 11 and the second pressure roller 15. Reference number 21 designates a third embossing nip, formed between the third embossing roller 9 and the third pressure roller 19. A third ply of web material V3 may be fed along a third feed path through the third embossing nip 21 where the third ply V3 can be embossed, in other words permanently deformed due to the mutual pressure exerted between the third pressure roller 19 and the third embossing roller 9, said pressure causing penetration of the embossing protuberances 9P of the third embossing roller 9 into the elastically yielding material 19B of the third pressure roller 19.
A glue dispenser 23 co-acts with the first embossing roller 5, by applying glue to the embossed ply V1, when it comes into contact with the cylindrical surface of the first embossing roller 5. The glue is applied to the surface portions of the embossed ply V1 corresponding with some or all of the head surfaces of the embossing protuberances 5P of the first embossing roller 5. In some embodiments the glue dispenser 23 may comprise an anilox roller 25 and an applicator roller 27. The anilox roller 25 may draw the glue from a glue storage tank 29 and transfer it to the applicator roller 27. The latter transfers the glue received from the anilox roller 25 to the embossed ply V1.
The glue dispenser 23 may be mounted on a trolley, slide or other movable unit 31, sliding in the direction of the double arrow f31 on guides 33 constrained to the base 3B of the load-bearing structure 3 of the embossing device 1. This makes it possible to move the glue dispenser 23 towards and away from the first embossing roller 5 for reasons that will be made clear below.
Still with reference to
The first embossing roller 5, together with the glue dispenser 23 and the first pressure roller 11, co-act with a lamination roller 41, which rotates about a rotation axis 41A substantially parallel with the rotation axis of the remaining rollers described above. The lamination roller 41 may be coated with an elastically yielding material, forming a coating layer 41B, or may be provided with a surface made of steel or another rigid material. The reference number 43 indicates an actuator configured for pushing the lamination roller 41 against the side cylindrical surface of the first embossing roller 5. Between the first embossing roller 5 and the lamination roller 41, a lamination nip 45 is formed, through which a web material can pass, formed for example by the pair of plies V1 and V2, superposed and guided around the first embossing roller 5.
Between the first embossing roller 5 and the third embossing roller 9, a nip 47 is formed for the passage of the embossed plies. A multi-ply product can pass through the nip 47, in the configuration shown in
The assembly of pressure rollers, embossing rollers, glue dispenser 23, and lamination roller 41 together constitute an embossing system.
The embossing device 1 may comprise a storage unit 51 which may contain a plurality of embossing rollers ready to be used to replace the embossing rollers 5, 7 and 9 temporarily mounted on the embossing device 1 between the sides 3C, 3D for processing the plies V1, V2 and V3. In the embodiment shown, the storage unit 51 is integrated into the embossing device 1, inasmuch as it is supported on the same base 3B that supports the sides 3C, 3D.
In other embodiments, not shown, the storage unit 51 may be separate from the actual embossing device 1 and may be placed laterally aside the embossing device at a distance therefrom.
The storage unit 51 may also be used in embossing devices other than the exemplary embodiment disclosed herein, for example in traditional tip-to-tip or nested type embossing units, or in embossing-gluing units, convertible embossing units, and in general any time it might be useful to have a store of interchangeable embossing rollers. Therefore, the features and embodiments shown herein of the storage unit 51 are independent from the specific characteristics of the embossing device.
The storage unit 51 may comprise a plurality of seats 53 specifically shaped to receive embossing rollers 55, 57, 59 that can be used to replace the embossing rollers supported by the sides 3C, 3D. As will be made clearer below, in practice the rollers in the storage unit 51 are provided to replace, preferably automatically, the embossing rollers 5 and 7, while the third embossing roller 9 may be fixed, i.e. not interchangeable, or interchangeable only by means of more complex, less frequent maneuvers.
In the embodiment shown, four seats are provided to support interchangeable embossing rollers, but it must be understood that the number of embossing rollers that can be housed in the storage unit 51 may be different, by providing a greater or lower number of seats 53. One of the seats of the storage unit 51 remains empty to allow replacement of the embossing rollers 5, 7.
Advantageously, in the example shown, the seats 53 of the storage unit 51 are vertically superposed, i.e. the storage unit 51 develops substantially in height, in other words it develops vertically. As shown in the accompanying drawings, the storage unit 51 is integrated into the embossing device, in the sense that it can be connected to the same load-bearing structure, typically the same base 3B.
Preferably, the storage unit 51 is laterally aside and separated at a distance from the embossing rollers that are in the working position (i.e. those temporarily supported between the sides 3C, 3D). In this way it is possible to avoid or reduce contamination of the embossing rollers in the storage unit by dust, splashes of glue or other contaminants that may be present in the embossing area, i.e. near the sides 3C, 3D. Furthermore, between the storage unit 51 and the sides 3C, 3D supporting the working rollers, a passage may be provided offering access to the storage unit 51 by an operator, or by a transfer device 65, described in greater detail below.
In some embodiments, as shown in
By means of the cross members 63 and the movement along them by the transfer device in the direction of the arrow f65, the storage unit 51 can be placed entirely separate from the embossing area, laterally aside and at a certain distance from the embossing area (between the sides 3C, 3D), upstream thereof with respect to the direction of advancement of the plies V1, V2, V3, i.e. towards the unwinder (not shown) where the parent reels wherefrom the plies are located. The structure thus defined, comprising the cross members 63 suitably supported by the sides 3C, 3D, and the advantageously vertically extending storage unit 51, may in some cases also serve as a structural support element for guide rollers for the plies fed to the embossing device 1.
Contrary to other known solutions, wherein the embossing rollers are held by a revolver transfer device, with an architecture of the type described, operation of the embossing device 1 is possible even if the transfer device 65 is broken down.
Placing the storage unit 51 laterally aside entirely separate from and upstream of the embossing area and at a certain distance therefrom allows for better access to the actual embossing device 1, contrary to what happens in known systems, where the embossing roller storage unit and the embossing area are superposed one above the other.
The architecture described makes it possible, for example, to access the embossing area and replace the embossing rollers using equipment other than the transfer device 65, if the transfer device is broken down, for example. The distance between the storage unit 51 and the embossing area makes it possible, if necessary, to access the embossing rollers located between the sides 3C, 3D by means of a bridge crane or other equipment external to the embossing device.
The seats 53 of the storage unit 51 are shaped with a curved lower portion so as to be able to hold end journals of the embossing rollers 55-59, 5, 7.
Some of the seats 53 of the storage unit 51 may be configured for receiving interchangeable cliché rollers 27. The transfer device 65 can be controlled and positioned to replace the temporarily operational cliché roller 27 with another cliché roller waiting in the storage unit 51. This is possible thanks to the way in which the transfer device 65 is mounted and moved with respect to the rest of the machine. In substance, there is obtained a system for the automatic replacement of cliché rollers, which may be useful, for example, when the embossing device 1 has to process plies V1-V3 of different widths, i.e. when there is a change of format. In this case, the cliché roller is replaced so that the axial length of the cylindrical working surface of the cliché roller is always roughly equal (or slightly less) than the width of the plies being processed.
Replacement of the cliché roller may also be useful when said roller does not have a continuous surface, but rather is designed to distribute glue according to a predetermined pattern. Automatic replacement of the cliché roller with the transfer device 65 allows for an easy change of the pattern according to which the glue is applied.
To enable easy replacement of the embossing rollers 5 and 7, they are supported in seats that can be easily opened and closed. More specifically, as can be seen in
In the embodiment shown, to simplify replacement thereof the second embossing roller 7 is supported by means of supporting bearings 73, in respective seats 75 formed by two portions 75A, 75B, similar to the portions 71A, 71B of the seat 71 that supports each supporting bearing 69 of the first embossing roller 5. In the embodiment shown, each seat of the second embossing roller 7 comprises a portion 75A solidly connected to the respective side 3C or 3D and a second portion 75B solidly connected to the movable unit 31. In this embodiment the portion 75B of each seat 75 of the supporting bearing 73 of the second embossing roller 7 has an angular extension greater than portion 75A and supports the respective supporting bearing 73 from below, so that when the movable unit 31 is moved away from the sides 3C, 3D of the load-bearing structure 3, taking the position shown in
Advantageously, to facilitate this movement, the second pressure roller 15 can be lowered by the actuator 37, thus moving the cylindrical surfaces of the second pressure roller 15 and the second embossing roller 7 mutually away from one another. A similar movement can be imparted to the first pressure roller 11 to facilitate removal of the first embossing roller 5 from the seat portion 71A.
When the movable unit 31 is in the position shown in
To that end, the transfer device 65 may comprise a pair of arms 81 vertically sliding along a numerically controlled vertical axis Z. This vertical movement may be guided along suitable guides 83 of the transfer device 65, in the direction of the double arrow f85. The arms 81 may end in hooks 81A that can engage the journals of the embossing rollers 5, 7, 55, 57, 59. A threaded bar 84 driven by a gear motor 85 can be used to move the arms 81 in the direction of the double arrow f85 for picking up and releasing the embossing rollers from the seats of the storage unit 51 and of the embossing device 1.
To facilitate engagement of the embossing rollers by the transfer device 65, the hooks 81A can interact with end support elements, mounted on the embossing roller journals.
The end support element 121 may also have an external sleeve 125, coaxial with the internal sleeve 122. The external sleeve 125 may be swivelingly supported on the internal sleeve 122, for example by means of rolling bearings 126, 127. The internal sleeve 122 and the external sleeve 125 are mounted so as to be free to rotate with respect to one another, but are axially blocked to one another.
In the embodiment shown, the external sleeve 125 is provided with an annular groove 128 with large bevels for engaging the hook 81A with which each arm 81 of the transfer device 65 ends. The lower part of the arm 81 and associated hook 81A are shown in a side view in the enlargement shown in
The end support element 121 allows precise centering of the hook 81A of the transfer device 65 in both a transversal and longitudinal direction, thanks to the bevels of the annular groove 128. Furthermore, the end support element 121 allows free rotation of the embossing roller on which the element is fitted, with respect to the hook 81A of the transfer device 65. This facilitates introduction of the embossing roller into the embossing device, and engagement between the teeth of a toothed wheel fitted onto the embossing roller (described below) and the respective transmission belt (also described below), or with a toothed wheel driving the embossing device.
In simplified embodiments, the internal sleeve 122 may be omitted and the external sleeve 125, on which the annular groove 128 is provided, may be mounted directly on the journal of the embossing roller with interposed bearings 126, 127, to allow rotation of the sleeve and the groove 128 with respect to the embossing roller journal.
The structure described enables easy replacement of the embossing rollers 5 and 7, while the third embossing roller 9 can be substantially immovable or in any case may be replaced by means of more complex operations, since its replacement may only be necessary from time to time.
To facilitate removal of the embossing rollers 5 and 7 and their replacement with one or other of the embossing rollers 55-59 present in the storage unit 51, according to advantageous embodiments a specific system for transmitting movement to the embossing rollers 5 and 7 is provided. Movement transmission is shown in detail in
Each embossing roller is provided with a toothed wheel fitted onto one of the journals. The wheel remains mounted on the embossing roller when it is transferred from the storage unit 51 to the working area and vice-versa. In
In particular, the toothed belt 91 is entrained around idle toothed wheels 95, 97 and around a driving toothed wheel, not shown, which is driven by a motor 99. Similarly, the toothed belt 93 is entrained around idle toothed wheels 101 and 103 and around a driving toothed wheel, not shown, that takes its movement from a second motor 105.
The third embossing roller 9 may be rotated by a third motor 106. In this way, the three embossing rollers 5, 7, 9 are each provided with their own independent motor. The pressure rollers 11, 15, 19 and the lamination roller 41 can be rotated through contact with the respective embossing rollers.
Each of the two toothed belts 91 and 93 forms a closed path, and is configured so that the toothed wheels 5D and 7D fitted on the embossing rollers 5 and 7 can be moved away from the toothed belts 91 and 93 without the need to take off the belts, due to the fact that the engagement contact between the toothed wheels 5D and 7D and the toothed belts 91 and 93 takes place on the outer surface of the toothed belts, i.e. on the surfaces of the toothed belts 91 and 93 facing the outside of the respective closed paths formed by the toothed belts. As will be understood by comparing
This makes it very easy to replace the first embossing roller 5 and the second embossing roller 7 with any one of the embossing rollers 55-59 present in the storage unit 51. Clearly, it is also possible to switch the position of roller 5 with roller 7 or vice-versa. As seen above with reference to
Having described the general structure of the embossing device 1, with reference to
In the configuration shown in
The second ply V2 is embossed by the second embossing roller 7 and by the second pressure roller 15 in the second embossing nip 17, and is then transferred from the second embossing roller 7 to the first embossing roller 5 in the first transfer nip 6 for the embossed plies V1 and V2.
Downstream of the first transfer nip 6 for the embossed plies, the two plies V1 and V2 are guided along the cylindrical surface of the first embossing roller 5 and through the lamination nip 45, where the first embossed ply V1 and the second embossed ply V2 are laminated between the first embossing roller 5 and the lamination roller 41, which is pressed against the embossing protrusions 5P of the first embossing roller 5. The plies V1 and V2 are thereby pressed against one another and caused to adhere to one another by the glue applied by the glue dispenser 23.
The third ply V3 is embossed between the third embossing roller 9 and the third pressure roller 19 in the third embossing nip 21 and is laminated or bonded to the first embossed ply V1 and to the second embossed ply V2 in the second transfer nip 47 for the embossed plies, formed between the first embossing roller 5 and the third embossing roller 9. The embossing protuberances 5P of the first embossing roller and the protuberances 9P of the third embossing roller can be configured and arranged so that in the transfer nip 47 at least some of the protuberances 5P of the first embossing roller 5 and at least some of the embossing protuberances 9P of the third embossing roller 9 are in a tip-to-tip configuration, i.e. pressed against one another. The pressure causes the glue applied by the glue dispenser 23 to bond the three plies V1, V2, V3 by seeping through the cellulose fibers that form them.
While the embossing rollers 5 and 9 may be configured so that the embossing protuberances 5P and 9P are in a tip-to-tip configuration in the second transfer nip 47 for the embossed plies, the embossing protuberances 5P of the first embossing roller and the embossing protuberances 7P of the second embossing roller 7 may be configured and arranged so that the embossed plies V1 and V2 are bonded in a nested configuration. In practice, the protrusions embossed by the second embossing roller 7 on the second ply V2 nest between the protrusions embossed by the first embossing roller 5 on the first ply V1.
The ply V1 is embossed between the first embossing roller 5 and the first pressure roller 11 in the first embossing nip 13 and receives the glue applied by the glue dispenser 23 on the head surfaces of the protrusions S1 formed on the ply V1. The ply V3 is embossed between the third embossing roller 9 and the third pressure roller 19 in the third embossing nip 21. In the second transfer nip 47 for the embossed plies, at least some of the protuberances 5P and 9P of the first embossing roller 5 and third embossing roller 9 are in a tip-to-tip arrangement similar to that described with reference to
While in
Using an embossing roller 9 provided with a micro-embossing engraving to obtain protrusions S3 of the type shown in
The web material N thus obtained is shown schematically in
The embossing rollers that are used as second embossing rollers 7 may be provided with embossing protuberances 7P of a height substantially less than the embossing protuberances 5P of the first embossing roller and with much greater density, thereby forming a base micro-embossing. The embossed protrusions S2 formed on the second embossed ply V2 may in this case not penetrate between the embossed protrusions S1 formed on the first embossed ply V1, as shown schematically in
A third ply V3 may also be applied in a tip-to-tip arrangement to a web material N thus formed, as shown in
While
In each of the
In the setup shown in
In
The embossing roller C, corresponding to the third embossing roller described above, is not operational.
In the various roller replacements described above, in order to find the correct synchronization between embossing rollers, it is sufficient to refer to the toothed wheels solidly fitted onto the roller rotation journals. References may be provided on the toothed wheels enabling the embossing rollers co-acting with one another to be correctly synchronized (for example tip-to-tip or nested).
In other possible configurations, the first embossing roller 5 and the second embossing roller 7 may be arranged in a “random” manner, instead of being nested.
The exemplary embossing device 1 of
The embossing device 1 of
The storage unit 51 includes a second stand 66, providing further seats 53 for additional spare embossing rollers 60, 62.
The storage unit 51 is integrally mounted on the supporting structure 3 of the embossing device 1, in quite the same way as in
The cross members or cross-beams 63, along which the transfer device 65 can move, can be connected to the base portion of the load bearing structure 3 of the embossing device 1 by means of uprights which develop vertically from the stands 64, 66. A double gantry structure can thus be obtained, which extends from the base of the support bearing structure 3 of the embossing device 1. This results in a compact layout, which is capable of withstanding high loads.
Similarly to the embodiment of
Quite in the same way as in the embodiment of
The vertical extension of the storage unit 51 improves accessibility to the spare embossing rollers by an external crane, bridge crane, overhead travelling crane, or other handling machinery and by the transfer device 65.
In some embodiments, the storage unit 51 can be further improved to provide enhanced accessibility to the spare embossing rollers and thereby improving handling thereof, e.g. in case a bridge crane is not available.
For instance,
The carriage 90 can be provided with wheels 94, which may rest and roll on the ground. A motor, for example an electric motor 95, can further be provided, to move the carriage 90 back and forth along guides 92 according to double arrow f 90 (
In the embodiment of
The carriage 90 allows removing the embossing roller supported thereon from the storage unit 51 even if no bridge crane or similar facility is available. Once the carriage 90 has been moved sideways out of the storage unit 51, the embossing roller supported thereon can be removed and replaced with another roller using any suitable means, for instance a shuttle external to the embossing device 1. The carriage 90 can be operated while the embossing device is operation.
Moreover in an embodiment according to
Handling of the rollers with the transfer device of
While in the above description, reference has been specifically made to a storage unit housing spare embossing rollers, it shall be understood that in all embodiments disclosed herein, specifically also the embodiments of
| Number | Date | Country | Kind |
|---|---|---|---|
| 102016000086447 | Aug 2016 | IT | national |
| Filing Document | Filing Date | Country | Kind |
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| PCT/EP2017/069860 | 8/4/2017 | WO |
| Publishing Document | Publishing Date | Country | Kind |
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| WO2018/036793 | 3/1/2018 | WO | A |
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