Spreader roller with roughened, helical surface

Abstract

Spreader roller with a rigid base body, an elastically deformable layer made of a rubber or an elastomer applied to the rigid base body, the surface of this elastic layer having a surface in the form of two oppositely extending helices (3, 4), the inner ends of which emanate from a central region and which extend outwards, characterized in that the elastic layer has a roughened or structured surface at the helices and the regions (5, 6) adjacent to the helices (3, 4) have a smooth surface.

Description

[0001] The invention relates to a spreading roller for spreading running flexible web material.

[0002] German patent application DE 20 51 425 A describes a device used to pull wet fabric during the dyeing and printing process. The device has a cylindrical roller with a rough or corrugated surface to grip the wet fabric.

[0003] German patent application DE 196 05 788 C1 discloses an abrasive machine for processing textile fabrics. The machine has an abrasive roller with segments attached to its surface. These segments are arranged in a spiral, starting in the middle of the roller and sloping downwards towards the ends.

[0004] The publication DE 32 33 214 A1 relates to a helical roller for stretching and expanding fabrics. The roller has a main roller body covered with spirally arranged brushes. These brushes are positioned at an angle and point in opposite directions from the center of the roller to its ends.

[0005] US Patent 4,566,162 A discloses a roller used for stretching and separating strips of material cut from a larger web. The roller has a rotating inner core covered with a flexible, rubber-like material. The outer surface of this roller has spiral grooves that ensure the material remains gripped and is pulled as it rolls. These grooves are angled to allow the roller to operate effectively, with the grooves becoming deeper from the center to the edges of the roller.

[0006] Publication EP 1,209,109 A2 describes a spreading roller for industrial applications. The roller has a rigid core covered with a flexible material containing slits. These slits are filled with another flexible material, allowing the roller to conform to different surfaces. Publication US 4,664,058 A describes a machine for coating flexible materials such as cardboard with a sterilizing liquid, such as hydrogen peroxide. The machine includes two rollers arranged one above the other, with a space (or gap) between them in which the coating takes place. The upper roller serves as a support, while the lower roller applies the sterilizing liquid. The lower roller has grooves on its surface that help distribute the liquid evenly as the material passes through.

[0007] From German patent application DE 295 22 011 U1, a spreading roller for spreading running flexible web material is known, comprising a rigid roller body with end bearing journals. A shell-shaped coating of elastomeric material is applied to the roller body. The elastomeric coating has incisions extending from its outer surface, inclined obliquely to the longitudinal axis of the roller body, and inclined from the inside out towards the respective end of the roller on both sides of the radial center plane of the roller. The incisions run in the form of uniform helixes and cause spreading during operation.

[0008] To prevent inadequate spreading effect in the central area, the inner cuts are offset from each other by 180°. To avoid impressions and damage in thin, delicate material webs, the outer edges facing the radial center plane of the roller are rounded or chamfered.

[0009] An elastomeric coating wears out within a few years. The roller body is then stripped of the remaining coating and a new one is applied. Spirals are then cut into this newly applied coating. Finally, the edges of the coating surface are rounded.

[0010] The production of the cuts in the coating significantly contributes to the repair costs of such a roller. Furthermore, the elastomeric coating is relatively thick to allow for sufficiently deep cuts. Commercially available spreading rollers of this type have an elastomeric coating at least 15 mm thick on the rigid roller body.

[0011] From US patent 2,594,846 A, a spreading roller is known which consists of two roller body sections with, among other things, conically tapered outer surfaces. This roller also features angled incisions whose inclination changes towards the ends of the roller, resulting in high manufacturing costs.

[0012] WO 2005 / 118 446 A1 discloses a spreading roller with helical incisions, which tapers towards the center and is covered with a sleeve to spread material webs without damage. The manufacture of this spreading roller is relatively expensive.

[0013] German patent application DE 202 19 858 U1 discloses a spreading roller in which incisions in an elastomeric coating are filled with a rubber material of a different hardness. This is intended to prevent damage to a delicate, thin web of material. However, the production of this spreading roller is relatively expensive.

[0014] Publication WO 2004 / 013399 A1 discloses a roller in which a roughened metallic foil is applied to a roller body. Among other things, the roughened surface can have a spiral pattern. However, it is not possible to stretch material webs wide, as there are no suitable opposing helixes. Practical experience has shown that it is difficult to apply metallic foils, or foils made of other materials, sufficiently firmly and permanently to a roller base.

[0015] The object of the present invention is to provide an inexpensive and functional spreading roller.

[0016] The problem is solved by the features of the independent patent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0017] To solve the problem, an elastically deformable layer is applied to a rigid, preferably cylindrical, base body. The base body does not necessarily have to be a straight cylinder; a concave or banana-shaped base body is also possible. The elastically deformable layer can consist of rubber or an elastomer. The surface of this elastic layer is treated to create a roughened or structured surface in the form of two opposing helixes. The cylindrical base body can be a conventional roller body, known, for example, from publication WO 2005 / 118 446 A1, and in particular made of metal. However, the cylindrical base body can also simply be a sleeve, preferably made of a plastic, and more preferably of a fiber-reinforced plastic.The cylindrical base body is preferably one piece, but can also consist of several parts, for example, it can be composed of two parts.

[0018] The roughened or textured surface is relatively slip-resistant compared to unroughened areas. The two helixes produced in this way, with their comparatively slip-resistant surface, facilitate the spreading of material webs. Since no relatively deep incisions are required, as specified, for example, in DE 295 22 011 U1, the flexible layer can be very thin. This allows for material and therefore cost savings compared to the prior art, which involves relatively deep incisions. Furthermore, producing a helically roughened or textured surface is relatively inexpensive compared to creating helixes through incisions. A helical roughening can be achieved cost-effectively by grinding. Since no relatively deep incisions are required, for example,In accordance with DE 295 22 011 U1, the material web cannot enter such incisions, which could damage the material web. Therefore, the present invention allows even particularly problematic material webs, such as aluminum foils or thin plastic films, to be stretched. Markings in the material webs then do not occur, or at least hardly at all. If a helical surface has worn down, it can be restored quickly and inexpensively. It is not necessary to first renew the elastically deformable layer. Instead, it only needs to be sanded down in order to then roughen or restructure the desired surface area.

[0019] The invention is generally based on the idea of ​​creating cost-effective, counter-helically oriented surfaces radiating from a central area that are slip-resistant, i.e., provide good grip compared to adjacent surface areas. If the elastic coating is already highly slip-resistant from the outset, it may suffice to only slightly recess the surfaces adjacent to the counter-helically oriented surfaces by, for example, no more than 1 mm, preferably no more than 0.5 mm, and particularly preferably no more than 0.2 mm, to achieve the desired results. However, it will generally be necessary to roughen the helically oriented surface areas to achieve the required slip resistance of these surface areas.

[0020] Unlike a spreading roller, such as that known from German patent application DE 295 22 011 U1, the elastically deformable coating can be thin. A coating thickness of just a few millimeters is sufficient. For single use, even a coating thickness of just a few tenths of a millimeter is adequate. Applying an elastic layer, for example 10 mm thick, is advantageous if the coating is to be restored according to the invention after wear, as described. It is also advantageous for manufacturing reasons to initially apply an elastic layer several millimeters thick. Therefore, an elastic coating initially applied to a rigid substrate will generally be at least a few millimeters thick, and in particular at least 3 mm, preferably at least 5 mm.Therefore, thinner layers of less than 3 mm are generally only found when the surface has been repeatedly sanded down due to wear and tear, resulting in the helical rough or textured surfaces becoming progressively thinner. Only in this way are elastic layer thicknesses of 0.2 to 3 mm achieved in practice.

[0021] In the case of spreader rollers with incisions, such as those designed according to DE 295 22 011 U1, the elastic layer is at least 15 mm thick. In contrast to such a prior art design, the present invention requires an elastic coating thickness of up to 12 mm, preferably up to 10 mm.

[0022] In one embodiment of the invention, areas adjacent to the helically extending roughenings or structuring are recessed. These helical recesses improve the spreading effect. The outward transport of a material web (spreading) takes place via webs with a roughened surface. Unlike the prior art, the recesses are not incisions several millimeters deep. Instead, each recess is only a few tenths of a millimeter, for example, only 1 / 10 of a millimeter. The sole purpose of the recesses is to prevent direct contact between a material web being spread and the areas that are not roughened during spreading.The material web should therefore lie firmly on the roughened areas during spreading, due to the indentations, but not on the areas in between. The depth of a indentation is thus advantageously chosen to achieve this goal while simultaneously minimizing the indentation depth. If a indentation is very shallow, the material web cannot penetrate it in such a way as to cause damage. Therefore, a depth of 1 mm is generally not exceeded. Typically, the depth is significantly less than this value and is less than 0.5 mm.

[0023] The helical indentations can be produced cheaply and quickly by grinding.

[0024] In one embodiment of the invention, the intended helical surface area is structured using a laser. While grinding can roughen the desired surface more cost-effectively, a surface roughened by grinding becomes unstable and brittle. This leads to relatively rapid wear and a relatively short service life of a manufactured spreading roller. Despite the higher manufacturing costs, surface treatment using a laser is therefore preferable in order to achieve a structured, grippier surface. Surface damage that leads to increased wear is thus avoided. Furthermore, the spreading roller surfaces can be produced reproducibly. A single type of spreading roller can therefore be manufactured identically with the same surface finish as often as desired.If a particular surface design has proven to be especially suitable or practical, the same three-dimensional surface structure can always be reproduced.

[0025] To create roughness or texturing on a surface using a laser, a mask can be employed. Laser light passes through openings in the mask and onto the surface to be roughened. Components of the surface are thus removed without damaging adjacent areas. Instead of a mask, the laser is preferably controlled and moved by computer to create the desired rough surface. After processing, the surface is no longer smooth, but instead exhibits, for example, small indentations distributed across it. The indentations are preferably very small. Their dimensions are particularly in the range of a few tenths of a millimeter or even a few hundredths of a millimeter. The maximum diameter of a indentation is preferably less than 1 mm, and particularly preferably less than 0.5 mm.The minimum diameter of a recess is preferably more than 0.01 mm, particularly preferably more than 0.05 mm. The maximum depth of a recess is preferably up to 1 mm, particularly preferably up to 0.5 mm. The minimum depth of a recess is preferably at least 0.01 mm, particularly preferably at least 0.1 mm.

[0026] Instead of numerous cutouts, the grip of the surface can also be increased by a different type of structuring. For example, a herringbone pattern could be created on the surface to appropriately increase the grip.

[0027] If a rough, helical surface is produced using a laser, in one embodiment of the invention the areas adjacent to the helical, rough surface are also ablated using the laser. This creates the desired helical depressions on which a material web should not lie during spreading. In this way, the desired surface of a spreading roller can be (re)produced in a single operation.

[0028] The elastic coating can be applied to a preferably metallic roller, which constitutes the aforementioned base body. In one embodiment of the invention, however, sleeves are used as the base body. Such a sleeve is made, in particular, of GRP or CFRP. One is made of glass fiber reinforced plastic (GRP). The other is made of carbon fiber reinforced plastic (CFRP). Such a sleeve is sufficiently rigid on one side. On the other hand, it is possible to elastically stretch the diameter of such a sleeve to a suitable degree. Furthermore, the sleeves are then advantageously relatively lightweight. To widen a web of material, such a sleeve with the spreading roller coating on it is mounted onto a preferably metal mother cylinder.

[0029] To fit such a sleeve onto a master cylinder, compressed air is pumped through bores in the master cylinder. The compressed air causes a minimal expansion of the sleeve's diameter, for example, by only one-tenth of a millimeter. With appropriate dimensions, this expansion is sufficient to slide the sleeve onto the master cylinder. The supply of compressed air is then stopped. This causes the sleeve to relax and then fit firmly onto the master cylinder. This technique is used in printing technology. It has been found that a sleeve can be connected to the master cylinder with sufficient strength in this manner that this technique can also be applied to spreading rollers.

[0030] The advantage of this design with a sleeve is that the wear parts are considerably easier to transport. This is due, firstly, to a significant weight saving, as there is no need to transport a complete roller with a heavy roller body. Furthermore, sleeves of different diameters can be nested inside one another, reducing the space required for transport and storage. According to the prior art, a used roller body of a spreading roller must be removed after the elastic lining has worn out and fitted with a new elastic lining, including the necessary cuts. Since this is generally not possible on-site, a worn spreading roller must first be transported to a supplier who can renew the elastic lining. In the case of sleeves, it is sufficient to replace only the sleeve. Because a sleeve is very inexpensive, sleeves with a spreading roller lining can be kept in stock.The replacement can then be carried out immediately on site. There is no need to provide two expensive roller bodies to perform such a replacement without production downtime.

[0031] Furthermore, a single master cylinder is sufficient to accommodate different spreading roller profiles and lengths. The appropriate sleeve is simply slid onto the master cylinder whenever, for any reason, the surface coating of a spreading roller needs to be changed or a different length of the spreading roller is required.

[0032] A master cylinder expediently has a multitude of holes or bores at only one end, through which compressed air escapes. This ensures that the compressed air can expand a sleeve as desired from the outset. While additional bores can be distributed across other areas of the master cylinder, it is advantageous to provide only a relatively small number of these additional holes through which compressed air is pumped. With such a distribution of bores or holes in the master cylinder, it is beneficial that the sleeve is always adapted to the master cylinder in terms of length. This ensures that the compressed air can expand the sleeve regardless of its position. Preferably, a master cylinder includes a stop up to which the sleeve can be pushed. In this embodiment of the invention, there are therefore no sleeves of different dimensions or lengths.However, since the spreading roller covering does not always have to extend the entire length of the sleeve, the invention includes an embodiment in which the sleeve is longer compared to the spreading roller covering, i.e., the area of ​​an elastic layer provided with helixes. The sleeve then always has the same length, matched to the master cylinder. The spreading roller covering, however, extends only over a portion of the sleeve.

[0033] In one embodiment of the invention, the sleeve is completely covered with an elastic coating. However, only a portion of the elastic surface is provided with helixes, so that only a portion acts as a spreading roller. The helixes therefore do not extend completely outwards to encompass all outer edge areas of the elastic coating. Manufacturing the elastic coating on the base body is relatively inexpensive.

[0034] Therefore, it can be advantageous to always provide a sleeve completely with an elastic coating as standard and to prepare only the required portion of the surface as the spreading roller covering. In this embodiment of the invention, only one type of sleeve with an elastic surface is required to produce spreading roller coverings of various dimensions. It is not necessary to stock a large number of different variants of sleeves with elastic surfaces in order to provide the desired spreading rollers.

[0035] The advantages of a sleeve can also be achieved with conventional spreading roller coatings. Such a sleeve can therefore also be provided with an elastic coating that, for example, has helical or annular undercuts in a manner known from the prior art, with the undercuts extending in opposite directions from a central area to achieve a spreading effect. The incisions can be filled with an elastic material of a different hardness, as described, for example, in EP 1 209 109 A2. The sleeve can, for example, be provided on its surface with helically arranged brushes or bristles running in opposite directions. Starting from a central area, the brushes or bristles can be inclined in opposite directions towards the outer ends of the sleeve, thus achieving a spreading effect.A spreading roller can taper towards a central area, as described in publication WO 2005 / 118 446 A1, and / or be covered with a sleeve described in that publication. A spreading roller can also thicken towards a central area. Incisions can always have the same depth. However, the depth of incisions can also increase or decrease from a central area. Therefore, in the case of sleeves, the desired surface finish of a spreading roller can be easily and cost-effectively provided for every application without having to replace a heavy and expensive roller body.

[0036] Spreading rollers according to the invention can comprise elastic coatings on the surface with more than two helixes extending in opposite directions from a central region. Two helixes extending in opposite directions need not necessarily originate from the center. Thus, "central region" does not mean that it is located exactly in the middle of a spreading roller. Rather, it refers to a region from which, for example, helixes extend outwards in opposite directions. The opposing helixes may have offset starting points. However, the starting points of the helixes in the central region can also be adjacent to one another. A central region can also initially be free of opposing helixes. The sleeve or a rigid roller body and / or the elastic surface can be electrically conductive. However, it is also possible that the rigid roller body or...the sleeve and / or the elastic surface with the incorporated coils are not electrically conductive.

[0037] Both cylindrical and tapered nut cylinders can be used in the case of a sleeve. The inner diameter of the corresponding sleeve can then be tapered and adapted to the shape of the nut cylinder.

[0038] An elastic surface coating or the spreading roller can be concave or convex. The surface coating or the spreading roller as a whole can, for example, be banana-shaped. The elastic surface coating can taper towards the middle, as is known, for example, from publication WO 2005 / 118 446 A1. Helixes can be uniform or non-uniform. In contrast to the prior art, there is no longer any, or practically no, cost difference depending on the helix shape chosen when a surface is processed using a laser.

[0039] If a spreading roller according to the invention comprises a conventional rigid roller body, this can be supported internally, for example by a continuous axle or by axle stubs. However, external support with fixed journals is also possible. If a spreading roller according to the invention comprises a master cylinder, this generally has external support, i.e., fixed journals, since air supply can then easily occur through a journal. However, master cylinders with internal support are also possible.

[0040] A spreading roller according to the invention can be actively driven by its own drive unit. Preferably, however, for cost reasons, it is a free-running spreading roller, which therefore rotates solely due to the tension of an adjacent web of material in conjunction with the web speed and the wrap angle that the web has with the spreading roller.

[0041] If a conventional rigid roller body is used as the rigid base body, it is made of aluminum, for example.

[0042] The two inner starting points of the opposing helixes can be radially offset in the manner known from DE 295 22 011 U1, but can also lie next to each other radially. These two starting points can be spaced apart axially, so that a central area is free of helixes. These two starting points can begin at the same height axially or even overlap slightly.

[0043] Multi-turn spreading rollers, i.e., rollers with several oppositely running helixes, can also be manufactured in order to achieve a more product-specific spreading or smoothing effect on the web being processed, tailored to the application.

[0044] Unless expressly stated otherwise, rollers according to the invention may have features known from the prior art, individually or in combination.

[0045] Fig. Figure 1 shows a cylindrical sleeve 1 made of fiber-reinforced plastic with an elastic coating 2 applied to it. The elastic coating 2 consists of an elastomer and is 5 to 10 mm thick. Starting from a central area, two helical sections 3 and 4 extend in opposite directions from the inside out. The two helical sections 3 and 4 have a roughened surface. The areas 5 and 6, which adjoin the two helical sections 3 and 4, are slightly recessed. As a result of the recession, the surfaces of these areas 5 and 6 are 1 / 10 mm below the roughened surface 3 and 4. The inner tabs 7 and 8 of the two helical sections 3 and 4 are offset from each other. Fig.Figure 2 shows the construction of a master cylinder 7. The master cylinder comprises a rigid metallic roller body 8. A line 9 for the supply of compressed air runs centrally through the roller 8. This compressed air supply 9 opens into bores 10 at one end of the master cylinder, which extend radially outwards. The sleeve 1 is slid over the master cylinder at this end. Compressed air is pumped outwards through the bores 10 via the supply 9. The sleeve 1 can be easily slid onto the master cylinder until a stop (not shown) is reached. The supply of compressed air is then stopped. The sleeve 1 then contracts slightly and now sits very tightly on the master cylinder. The recessed surfaces can also be roughened, but this is generally disadvantageous. Therefore, the surfaces of the recessed areas are generally smooth compared to the roughened areas.These areas adjacent to the spirals with roughened surfaces are particularly smooth if they have not been recessed.

[0046] If a sleeve needs to be replaced, compressed air is first supplied. This causes the sleeve to expand slightly, allowing it to be removed from the master cylinder.

[0047] The bores 10 need not be limited to one end of the master cylinder. Additional bores can also be distributed across the rest of the roller body, through which compressed air can be pumped to the outside.

Claims

[1] Spreading roller with a rigid base body, an elastically deformable layer applied to the rigid base body, the layer being made of a rubber or an elastomer, wherein the surface of this elastic layer has a surface in the form of two oppositely extending helixes (3, 4) the inner ends of which extend from a central region and extend outwards, characterized by , that the elastic layer on the helixes has a roughened or structured surface and the areas (5, 6) adjacent to the helixes (3, 4) have a smooth surface. [2] Spreading roller according to claim 1, wherein the elastic layer (2) applied to the rigid base body is up to 10 mm thick, preferably up to 5 mm thick. [3] Spreading roller according to one of the preceding claims, wherein the areas (5, 6) adjacent to the helixes (3, 4) are recessed relative to the surface of the helixes (3, 4), preferably by 1 / 10 millimeter to 1 mm. [4] Spreading roller according to one of the preceding claims, wherein the rigid base body is a sleeve (1). [5] Spreading roller according to the preceding claim, wherein the sleeve (1) is made of a fiber-reinforced plastic. [6] Spreading roller according to one of the two preceding claims, wherein the sleeve (1) sits on a mother cylinder (7). [7] Method for producing a spreading roller according to one of the preceding claims, wherein an elastic surface is roughened or structured helically using a laser or by grinding. [8] Method for manufacturing a spreading roller according to the preceding claim, wherein a sleeve (1) with a spreading roller covering (2, 3, 4) located thereon is pushed onto a mother cylinder (7).

Images