The present invention relates to the handling of the embossing rollers in paper converting plants.
It is known that the embossing units are commonly used in the paper converting plants to produce, for example, rolls of kitchen paper, toilet paper, paper towels and so on. The embossing has the main function to confer greater volume, higher liquid absorption capacity and surface designs to the plies that form the paper web which is subsequently rolled on cardboard tubes by means of a rewinder and then subjected to transverse cut in cutting-off machines.
Essentially, the embossing process implies the passage of one or more plies of paper between an embossing roller, the surface of which is provided with tips or reliefs according to a predefined scheme, and a counter-roller. Therefore, a ply that is smooth before the embossing process takes place, is so shaped as to exhibit a set of reliefs and depressions corresponding to the arranged embossing pattern on the embossing roller. If the web is composed by more plies, for example two, these can be both embossed and then joined together by gluing in a so-called tip-to-tip configuration, in which the reliefs of a ply are opposite to the other's ply reliefs, or in so-called nested configuration in which the reliefs of a ply are in each other's ply depressions.
The machines in which the embossing process takes place are commonly called “embossing units”. Generally, the embossing units are arranged to allow the rollers exchange, i.e. the replacement of one or more embossing rollers to change the embossing patterns on the paper or for maintenance operations. Generally, such embossing units have a structure comprising a fixed part and a movable part which is moved with respect to the fixed part to allow access to the parts supporting the embossing rollers in order to release and replace the latter when required. U.S. Pat. No. 7,618,004, EP1765584 and U.S. Pat. No. 7,458,538 disclose embossing units of this type.
The embossing rollers for use in machines of the type described above are stored in special areas of the plant and are shaped specifically to be picked up and moved by suitable handling systems arranged in the paper converting plant.
The main purpose of the present invention is to provide a system which allows to move the embossing rolls in a paper converting plant in a simple, effective and automatable way.
This result has been achieved, in accordance with the present invention, by means of a paper converting plant comprising means for producing logs of paper material starting from one or more paper webs fed by corresponding reels, with one or more unwinders on which the paper reels are arranged, an embossing unit that receives at least one of the webs coming from the paper reels and provides to its embossing, a bridge crane with arms provided with grippers, and a rewinder that produces logs using the webs coming from the embossing unit, wherein the embossing unit is arranged to be configured in a first use configuration in which one or more embossing rollers positioned inside it are stably locked to respective supports and a second removal configuration in which said one or more embossing rollers are disengaged from said supports such that the one or more embossing rollers can be extracted from the embossing unit when the plant also comprising a storing unit in which are stored one or more embossing rolls according to a predefined storage order such that each embossing roller occupies a known and predetermined position in the same storage unit, the bridge crane being provided above the one or more unwinders, the embossing unit, the rewinder and the storing unit. Each embossing roller has a respective longitudinal axis. The plant further comprises interface means reversibly associable to the grippers of the bridge crane and to each of the embossing rollers in a phase of movement of the embossing rollers, which interface means are interposed between the bridge crane and an embossing roller selected among those located in the embossing unit and in the storage unit and exhibits a first part shaped to be engaged by the grippers of the bridge crane and a second part shaped to engage the axial ends of the embossing roller providing an axial constraint that prevents the translation of the same embossing roller along the direction of its longitudinal axis.
Thanks to the present invention, it is possible to move the embossing rollers in a safe and reliable way. Furthermore, the process can be automated, with further benefits in terms of safety and costs.
These and other advantages and characteristics of the invention will be best understood by anyone skilled in the art thanks to the following description and to the attached drawings, provided by way of example but not to be considered in a limitative sense, wherein:
A handling system in accordance with the present invention can be used, for example, in a plant of the type illustrated in
In this example, it is also provided a bridge crane (6) equipped with operating arms (60) arranged to handle both the parent reels (PR) and the embossing rollers (4). The handling of the parent reels (PR) is provided when a parent reel is almost exhausted on one of the unwinders (3) and must be substituted with a new one that is ready to be picked up in a waiting point (P) of the plant.
The handling of the embossing rollers (4) is provided to replace an embossing roller as further described in the following. The arms (60) of the bridge crane (6) are provided with grippers (61) at their free ends (
Advantageously, in accordance with the present invention, it is provided to arrange, in a predetermined point (A) of the plant, a pair of bars (8) each of which has an upper part (80) suitably shaped to be engaged by a corresponding arm (60) of the bridge crane (6) and a lower part (81) suitably shaped to engage an end (40) of an embossing roller (4). Bars (8) are shown in
With reference to the example shown in the drawings, the upper part of each bar (8) has a pin (82) placed transversely between two side surfaces (83) of the same bar (8) that are spaced apart by a predetermined value (t). The pin (82) is shown in
The lower part of each bar (8) has, on the outer side of a respective surface (83), an engagement area with a blind hole (85) perpendicular to the same surface (83) and, below the hole (85), an appendix (86) defining a step (86) with a ramp (87) descending towards the same side surface (83) as shown by way of example in
As shown by of example in
In the step of removing a roller (4) from the embossing unit (2), the latter is disposed in the unlocking configuration to allow the removal of the chosen roller (
Therefore, a system according to the present invention comprises:
The interface means, that according to the example described above are constituted by bars (8), allow the use of the bridge crane (6) for handling both the embossing rollers (4) as previously said and for handling the reels (PR). The grippers (61) and the arms (60) of the bridge crane (6) do not need to be configured in a special way to fit the conformation of the reels (PR) or the conformation of the embossing rollers (4). Therefore, the bridge crane (6) normally provided in the plant in order to move the reels (PR) and other heavy loads can also be used for safely moving the embossing rollers (4) and handling them according to a predefined handling program that can be automatically controlled by programmable control systems of the plant itself. In particular, as mentioned above, the bridge crane (6) is capable of moving the embossing rollers (4) between the embossing unit (2) and the storing unit (7) or the waiting point (K) where the embossing rollers (4) subjected to maintenance or the rollers (4) intended to be brought to the storing unit (7) can be placed. For example, in said waiting point (K) can be used an automated cart of the AGV type (100) on which the embossing rollers are arranged (4). The waiting point (K) is shown by way of example in
Alternatively, or in addition, at the point (K) the embossing rollers (4) can be arranged on simple carriages (101). On the same AGV (100) can be positioned a support (110) on which can be placed, for example, the rollers (4) to be subjected to maintenance. The support (110) can have, for example, a box-like shape e adapted to hold a roll (4).
It is understood that the term “grippers” designates any gripping device mounted on the bridge crane arms.
The bridge crane (6) shown in the accompanying drawings slides along a corresponding fixed guide (9) which develops above the machines constituting the plant. The bridge crane is of the type in which the arms (60) are each bound to a carriage (64) mounted on a superstructure (62) that slides along the fixed guide (9) and are operated by respective actuators (63). The carriages (64) are moved in a transverse direction relative to the guide (9) by corresponding horizontal actuators (65) for moving the arms (60) towards each other or away from each other by moving them parallel to themselves as indicated by arrows “F”.
As schematically shown in
The bridge crane is therefore freely usable also for other actions and not only for handling the embossing rollers. In practice the details of execution of the present invention may vary in any equivalent way for what concerns the individual elements described and illustrated without thereby departing from the scope of the adopted solution and thus remaining within the limits of the protection granted to the present patent.
Number | Date | Country | Kind |
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UB2016A0458 | Jan 2016 | IT | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IT2016/000285 | 12/2/2016 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2017/130228 | 8/3/2017 | WO | A |
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Number | Date | Country | |
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20190071272 A1 | Mar 2019 | US |