Sleeve, winding device and method for multiple, successive winding of webs into material rolls

Description

[0001] The invention relates to a winding device and a method for the multiple, successive winding of webs into material rolls. The prior art involves unwinding film and webs onto winding cores, with these webs remaining on the winding core for further transport and processing. These cores can be made of cardboard, plastic, or metal, with cardboard being the most common. To reduce material costs and waste, there are approaches to coreless winding. The material is wound directly onto a winding shaft, which can be reduced in outer diameter after the winding process. During the reduction, the innermost layers of the roll assume the supporting function of the core. Winding shafts known in the prior art generally have the design shown below.

[0002] These winding shafts have three or more shells arranged around the circumference. These shells can be expanded to a larger diameter by inflating an air hose inside the winding shaft core. The film is wound up in this state. After the winding process is complete, the air is released, and the shells retract to their original, smaller diameter under spring force. In this state, the inner layers of the roll support the film roll, creating a gap between the shell and the winding shaft. This allows the finished roll to be pulled off the winding shaft.

[0003] The publication US 2013 / 01 86997 A1 shows an exemplary sleeve for use with a winding shaft, wherein the features of the preamble of claim 1 are disclosed.

[0004] However, this solution has two major disadvantages. The clamping elements are heavy and significantly reduce the load-bearing cross-section of the winding shaft. This results in narrow working widths and / or low line speeds, especially for 2" applications (2" is the outer diameter of the winding cores).

[0005] The second disadvantage is the gaps that form between the trays when the winding shaft is expanded. Film is pressed into these gaps during winding. This makes it difficult to impinge on the trays after winding, reducing the reliability of the peel-off process. Furthermore, the gaps are visible inside the roll, which is a negative quality indicator.

[0006] Coreless winding shafts are also known, which consist of a tube with numerous holes. After the winding is carried out on the tube, compressed air is used to create an air cushion between the tube and the winding, which facilitates the removal process. However, this process is not very reliable.

[0007] The object of the present invention is therefore to propose a winding device and a method in which the aforementioned disadvantages are eliminated or at least reduced.

[0008] According to the invention, this object is achieved by all features of claim 1.

[0009] The idea is based on a standard winding shaft for conventional winding cores, which can, however, be converted to a coreless winding shaft by sliding on a core and / or can be used without conversion. The standard winding shaft preferably comprises adjusting elements which can be moved relative to the winding shaft, with a component of the displacement pointing radially outwards. To enable displacement, the adjusting elements are drivable, with a pressure chamber and / or a flexible hose preferably being provided within the winding shaft. A pressure chamber can, for example, be filled with a fluid which is pressurized for the purpose of moving the adjusting elements. A flexible hose can also be easily inflated, i.e. pressurized with a larger volume of fluid.

[0010] By sliding on and securing a very thin-walled spiral sleeve, this shaft is transformed into a coreless winding shaft. This sleeve consists of a one-piece, cylindrical shell comprising two edge regions that overlap to form an overlap area. In its resting state, this sleeve, according to the invention, has an inner diameter that is smaller than or equal to the outer diameter of the winding shaft. This creates a nearly circular surface that can be adjusted to different diameters by tensioning and untensioning. In its untensioned state, the sleeve has a first diameter. If the adjusting elements are then moved – with a radial outward movement component – the sleeve is transferred into a tensioned state, whereby the overlap area decreases. One could also say that the mutual shortest distance between the two edges decreases.In this tensioned state, the sleeve has a second diameter, which differs from the first diameter. In particular, the second diameter is larger than the first diameter.

[0011] The material is elastic, meaning that after relaxing it returns to its original position and resumes its original geometry.

[0012] To ensure sufficient preload on the winding shaft, a sleeve can have an inner diameter that is smaller than the outer diameter of the winding shaft. Thus, the inner diameter of the sleeve can be up to 10%, preferably up to 5%, smaller than the outer diameter of the winding shaft. The inner diameter of the sleeve refers to the diameter the sleeve assumes when it is not pushed onto the winding shaft. This inner diameter ensures that the sleeve returns from the tensioned state to the relaxed state.

[0013] Travel limiters and / or force limiters can act on the adjusting elements within the winding shaft, with the travel limiters and / or force limiters being particularly adjustable. In this way, the travel of the adjusting elements can be limited radially outward, so that the second diameter assumes a desired value. With conventional winding cores, such travel limiters or force limiters are not necessary, since a core known from the prior art already limits the travel or force due to its strength.

[0014] A key advantage of the invention is that one winding shaft can be used for winding both with and without conventional winding cores. Only the core needs to be pushed on. This reduces conversion times and the high initial costs associated with two complete winding shafts.

[0015] Another very important advantage of the invention is the absence of gaps when tensioned. This results in a substantially round interior of the material roll. This is a quality feature for the sale of the material rolls.

[0016] In an advantageous embodiment of the invention, the edges of the core run parallel to the core's main axis of inertia. In this case, the edges run parallel to the rotational axis of the winding shaft when the core is pushed onto it. The core is preferably attached to the winding shaft in such a way that the edge resting in the area of the overlap is located at the rear end of the core, viewed in the direction of rotation of the winding shaft. In this case, the front end of the material web can be placed behind the trailing edge of the core when it is rewound. This reduces the impact that occurs after each revolution of the winding shaft when the material web hits the beginning of the web, resulting in a more even wind. This is even advantageous for thin material webs.

[0017] In another advantageous embodiment, the edges extend at an angle to the main axis of inertia of the sleeve, in particular in a spiral shape. With such an embodiment, an imbalance of the sleeve can be reduced or even eliminated.

[0018] It is also advantageous if the sleeve material is made of carbon fiber reinforced plastic (CFRP). In particular, the sleeve can be made entirely of this material. A sleeve made of CFRP can have very thin walls. This prevents imbalances in the winding shaft fitted with the sleeve, allowing the winding shaft to run smoothly, which is particularly advantageous at high winding speeds. The high strength of this material also ensures that the outer circumference retains a very good circular shape when the diameter is increased, which has a positive effect on the quality of the winding.

[0019] In an alternative or additional embodiment of the invention, the material of the sleeve comprises at least partially steel, in particular spring steel. This material allows for the production of very cost-effective sleeves.

[0020] Furthermore, the above-mentioned object is achieved by a method according to claim 7 for successively winding material web sections into material rolls.

[0021] With this method, the same advantages are achieved as with the winding device according to the invention, whereby the sleeve can remain on the winding core in this method or can be removed with the finished material roll. Fig. 1A coreless winding shaft according to the state of the art Fig. 2How Figure 1 , but with outwardly shifted adjusting elements Fig. 3Cross section of a winding shaft with a sleeve in the relaxed state Fig. 4How Figure 3, but in the tensioned state Fig. 5Perspective view of the essential components of the Figure 3 Fig. 6Perspective view of a further embodiment of a sleeve Fig. 7An embodiment of a winding shaft arrangement provided with a fixing element Fig. 8An embodiment of a winding shaft arrangement provided with another fixing element Fig. 9A winding device according to the invention

[0022] The Figure 1shows a section through a so-called coreless winding shaft 1 according to the prior art. The actual winding shaft can be seen, which comprises a supporting tube 10. The supporting tube 10 is surrounded by a plurality of shell parts 11, which in their entirety preferably surround the tube 10 concentrically and can rest on its outer circumference in the relaxed state. The shell parts 11 can be displaced in the radial direction of the supporting tube 10 via adjusting elements 12, of which at least one is assigned to each shell part 11. In order to be able to displace the adjusting elements evenly and simultaneously, at least one force supply device is provided, which in the present Figure 1as an expandable cavity, for example, as a tube 13. By filling it with a pressurized fluid, preferably air, this cavity can be expanded in the radial direction and thus pushes the adjusting elements outwards, which is illustrated by the arrows 14. The state in which the adjusting elements are displaced outwards is shown in the Figure 2 shown.

[0023] The Figure 3 now shows a first embodiment of a sleeve 50 in a sectional view. This sleeve can be pushed onto a winding shaft, which also comprises a supporting tube 10. Also provided within the supporting tube 10 are adjusting elements 12 and an expandable cavity 13, the structure and function of which are analogous to the prior art. Features that are associated with the Figures 1 and 2 can therefore be associated with characteristics related to the Figures 3 to 6described or shown by these figures. The sleeve extends in the circumferential direction around the supporting tube 10, the sleeve extending over an angle of more than 360°. In other words, the edge 51 of the sleeve lies on the outer circumference of the sleeve 50 and the edge 52 of the sleeve lies on the inner circumference of the sleeve 52. In still other words, the sleeve 50 overlaps itself in an overlap region which is represented by the double arrow 53. In this relaxed state, in which the sleeve 50 can have touching contact with the supporting tube 10, the sleeve 50 has a first diameter D1, it being noted that due to the overlap the sleeve does not have an ideally round cross-section.

[0024] The Figure 4 now shows the arrangement of the Figure 3, but with the adjusting elements 12 displaced outwards, as seen in the radial direction of the supporting tube 10. The displacement of the adjusting elements again preferably proceeds as in the prior art. During the displacement of the adjusting elements, the parts of the sleeve that lie one above the other in the overlap region move relative to one another. In other words, the edges 51 and 52 approach one another. One can also say that the overlap region 53 is or will be reduced in size. In this tensioned state, the sleeve 50 has a diameter D2 that is larger than the diameter D1.

[0025] Once the tensioned state has been reached, the winding process can now begin and a material roll can be formed on the core 50. If a material roll has been wound completely and must now be removed from the core, the core 50 is returned to the relaxed state according to Figure 3in which the diameter D1 of the sleeve 50 is now smaller than the inner diameter of the material roll.

[0026] The Figure 5 now shows a perspective view of a supporting tube 10 and the sleeve 50 pushed onto it. It can be seen that the edge 51 runs parallel to the main axis of inertia of the sleeve 51, which runs close to or on the axis of rotation of the winding shaft and thus of the supporting tube 10.

[0027] The Figure 6 now shows a further embodiment of a sleeve 50. The illustration is also perspective. Deviating from the embodiment according to the Figure 5Here, the edge 51 (and thus also the edge 52 (not shown) does not run parallel, but at an angle to the principal axis of inertia of the sleeve 50. In other words, the edge 51 runs spirally. The circumferential angle of the edge 51 is preferably more than 360°. Also present, but not shown, in this embodiment is an overlap region. The properties according to which the edges approach each other or the overlap region decreases to transfer the sleeve from a relaxed state to a tensioned state are also retained.

[0028] To prevent axial displacement of the sleeve 50 relative to the supporting tube 10, in an advantageous embodiment, at least one fixing element can be provided, which reduces or even prevents said axial displacement. This is particularly important when a finished roll of material is to be removed from the sleeve. Without a fixing element, there is a risk that the sleeve will be accidentally displaced. With an automatic roll change, this would require additional intervention to properly reposition the sleeve. Figure 7shows a first embodiment in which a pin 20 is provided on the supporting sleeve, the pin representing the fixing element. The sleeve 50 has a complementary hole 60 into which the pin can engage. To facilitate sliding on the sleeve 50, the pin 20 can comprise a bevel 21 or be movably mounted on the supporting tube. In the embodiment according to Figure 8 a ring 22 is provided which can be pushed onto the supporting pipe and fastened there.

[0029] This ring can now support the fixing element. Such a ring can also be part of a fixing element. The advantage of this embodiment is that the ring can be removed again, so that the winding shaft can also be used with conventional winding cores, which remain connected to the material roll after winding. In the present embodiment, the fixing element can be designed as a screw 23, with which the core can be pressed against the supporting tube.

[0030] A sleeve and a winding shaft explained in the context of this description can together form a winding shaft arrangement according to the invention.

[0031] The Figure 9shows a winding device 100 according to the invention, which comprises a winding shaft arrangement 101 according to the invention. A material web 102, which is, for example, a plastic web, can be fed to a contact roller 104 via at least one guide roller 103. It is preferred if the contact roller can be used to press the material web 102 against the winding shaft arrangement. The winding device is constructed and operated in such a way that the winding shaft arrangement rotates in the direction R. When a new beginning 105 of a material web 102 is fed to form a new roll, it is advantageous if the beginning 105 is placed on the core shortly behind the edge 51, viewed in the direction R. "Short" refers to an angular range from 0 to a maximum of 30 degrees. In this way, the step 51 resulting from the edge 51, but also the step resulting from the beginning 105, is reduced.

Claims

1. Winding device with a winding shaft (10) and a sleeve (50) for successively winding up sections of material web into material windings, wherein the material windings are in direct contact with the sleeve, wherein the material windings are displaceable relative to the sleeve, wherein the sleeve remains in a fixed position during the displacement of the material winding relative to the winding shaft, wherein the sleeve comprises a one-piece workpiece circumscribing a cylinder, which comprises two edge regions (51, 52) each having an edge, wherein the sleeve has a first diameter in a relaxed state, wherein the sleeve has a second diameter in a tensioned state which differs from the first diameter, wherein the sleeve undergoes an elastic deformation in the tensioned state compared to the relaxed state, characterized in that the edge regions overlap, and in a resting state, in which the sleeve is not located on the winding shaft, the sleeve has an inner diameter which is smaller than or equal to the outer diameter of the winding shaft.

2. Winding device according to claim 1, characterized in that the edges of the sleeve extend parallel to the main axis of inertia of the sleeve.

3. Winding device according to any one of the preceding claims, characterized in that the edges of the sleeve extend in a spiral form to the main axis of inertia of the sleeve.

4. Winding device according to any one of the preceding claims, characterized in that the material of the sleeve comprises carbon fiber-reinforced plastic.

5. Winding device according to any one of the preceding claims, characterized in that the material of the sleeve at least partially includes steel, in particular spring steel.

6. Winding device according to any one of the preceding claims characterized in that the inner diameter of the sleeve in the idle state is up to 10%, preferably up to 5%, smaller than the outer diameter of the winding shaft.

7. Method for the successive winding of sections of material web into material windings, wherein - a sleeve (50) is or is arranged on a winding shaft (10) while the sleeve is in a relaxed state with a first diameter, - the sleeve is brought into a tensioned state with a second diameter, wherein the second diameter is greater than the first diameter, - the section of material web is wound onto the sleeve to form the material winding, - the sleeve is returned to the relaxed state, - the material winding is pulled off the sleeve, wherein the sleeve comprises a one-piece workpiece circumscribing a cylinder, which comprises two edge regions (51, 52) each having an edge, wherein during the transfer of the sleeve from the relaxed state to the tensioned state, the distance between the edges is reduced, characterized in that the edge regions overlap and in a resting state, in which the sleeve is not located on the winding shaft, the sleeve has an inner diameter which is smaller than or equal to the outer diameter of the winding shaft.