Abstract
A folding roller for use in a folding device for folding a fold is disclosed. At the folding device a substrate to be folded is pushed into an inlet roller nip of folding rollers rotating in opposite directions by a folding knife for forming a fold. The folded-away substrate is transferred from the folding rollers to a belt line guided about the folding rollers and consisting of transport belts for the purpose of onward transporting the folded product. The folding roller in the regions in axial extension in which at least one transport belt at least partially wraps the folding roller includes at least one rubber-elastic insert.
Claims
1. A folding roller, comprising: a cylindrical folding roller body, wherein the folding roller body has a circumferential insert groove that is part of a circumferential groove which, in addition to the circumferential insert groove, has a circumferential transport belt groove; a transport belt, wherein the transport belt is guided on the cylindrical folding roller body in an axial region of the cylindrical folding roller body; and a rubber-elastic insert disposed on the axial region, wherein the rubber-elastic insert is disposed in the circumferential insert groove.
2. The folding roller according to claim 1, wherein the rubber-elastic insert has a width such that the transport belt lies at least partially on the rubber-elastic insert.
3. The folding roller according to claim 1, wherein an outer shell surface of the folding roller body protrudes over an outer shell surface of the rubber-elastic insert and wherein the transport belt projects into the circumferential groove.
4. The folding roller according to claim 1, wherein the rubber-elastic insert is a compressible material.
5. The folding roller according to claim 1, wherein the rubber-elastic insert is an incompressible material.
6. The folding roller according to claim 1, wherein the rubber-elastic insert is an endless ring of rubber-elastic material.
7. The folding roller according to claim 6, wherein the endless ring has a circular or polygonal cross-section.
8. The folding roller according to claim 1, wherein the folding roller has a region in limited axial extension which is not covered by a transport belt and wherein a second rubber-elastic insert is stocked in the region in limited axial extension.
9. The folding roller according to claim 1, wherein the rubber-elastic insert is a strip of finite length of rubber-elastic material and wherein the finite length corresponds to a length of a circumference of a neutral fiber in an assembled state on the folding roller.
10. The folding roller according to claim 1, wherein the circumferential insert groove has a cross-section such that no fixing element is used for clamping the rubber-elastic insert in the circumferential insert groove.
11. The folding roller according to claim 10, wherein the circumferential insert groove has a cross-section that diminishes in an outward radial direction.
12. The folding roller according to claim 1, wherein the rubber-elastic insert has a hardness of approximately 25 to approximately 100 shore.
13. The folding roller according to claim 1, further comprising: a second rubber-elastic insert disposed on a second axial region of the cylindrical folding roller body; wherein the second axial region is adjacent to the axial region.
14. The folding roller according to claim 13, wherein a width and/or an elasticity of the rubber-elastic insert differs from a width and/or an elasticity of the second rubber-elastic insert.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 is a schematic folding device for forming a fold by a folding knife and folding rollers;
(2) FIG. 2 is a three-dimensional representation of a folding roller pair consisting of two folding rollers with associated belt line;
(3) FIG. 3 is a two-dimensional representation of a folding roller pair with shown folding roller nip;
(4) FIG. 4 is a folding roller according to the invention without transport belts, but with rubber-elastic inserts;
(5) FIGS. 5a-c illustrates possible configurations of the rubber-elastic inserts, wherein the transport belt lies on the insert over its entire width;
(6) FIGS. 6a-c illustrate possible configurations of the rubber-elastic inserts, wherein the transport belt over its width lies on the insert only partially;
(7) FIGS. 7a-c illustrate possible configurations of the rubber-elastic inserts, wherein the transport belt over its entire width lies on the insert and in the region of the wrap forms a calotte-shaped outer shell surfaces; and
(8) FIG. 8 illustrates a possible embodiment of the folding roller according to the invention with rubber-elastic inserts in first and second regions.
DETAILED DESCRIPTION OF THE DRAWINGS
(9) The present invention relates to a folding roller with a cylindrical folding roller body with one or more regions in axial extension, in which in each case at least one transport belt is guided and on which at least one transport belt at least partially wraps the folding roller, and includes at least one rubber-elastic insert.
(10) In addition to this, the invention relates to a device for forming a fold which comprises at least one folding roller according to the invention.
(11) FIG. 1 shows schematically a folding device 1 for folding sheets of a substrate, as are employed for example in offset, intaglio or even printing machines with variable print form printing processes such as for example inkjet printing. The sheet to be folded comes to lie on the folding table 4 above the folding rollers 10 and is pushed into the roller nip 15 of the folding rollers 10 by the folding knives 3. As an exemplary embodiment of such a knife folding or chopper folding device, an embodiment with folding drum 2 is shown. Here, the folding drum 2 rotates about its longitudinal axis and comprises a gearing which likewise rotates the folding knife 3 about its longitudinal axis. By suitably matching the geometries of folding drum 2 and folding knife 3, the tip of the folding knife 3 moves on a vertical plane, which preferentially runs through the middle of the folding roller nip. As alternative forms of the folding knife 3, rocker arms are also known in the prior art which perform a rotatoric movement in a plane that is parallel to the axis of rotation of the folding rollers 11. Alternatively, a rocker arm with oscillating movement of a folding knife 2 can likewise be employed, which with its rocking movement pushes the sheet to be folded between the folding rollers.
(12) When the sheet to be folded or the stack of sheets to be folded is pushed into the folding roller nip 15, the same is gripped by the outer shell surface of the folding rollers 10 and the at least one transport belt 21 at least partially wrapping the folding rollers 10 and pulled through the roller nip 15, whereby a fold parallel to the axis of rotation of the folding rollers 11 is formed. The folded product is transported onwards with the belt line 20 with the folding spine up front and delivered on a delivery belt 34 for example via a paddle wheel 30.
(13) FIG. 2 shows the folding roller pair consisting of two folding rollers 10 rotating in opposite directions about the respective axis of rotation 11. In addition, the belt line 20 which ensures the transport of the product to be folded, is shown in FIG. 2. The belt line 20 consists of at least one transport belt 21 each, which is driven by the rotation of the folding roller 10, clamps the folded product or product to be folded between the two transport belts 21 and transports the same by frictional connection. For this reason, a transport belt generally has a higher coefficient of friction than the outer shell surface of the folding roller body 12. Preferentially, multiple transport belts 21 are employed over the length of the folding roller 10 and thus over the maximum width of the product to be folded, whereby these transport belts 21 in axial extension of the folding roller 10 are located on both folding rollers 10 in the same position, so that the respective opposite transport belts 21 can clamp the product to be folded. In the shown example, three transport belts 21 are employed over the width of a folding roller 10.
(14) FIG. 3 shows the folding roller body 12 of the folding rollers 10 in lateral and front view; it shows that in the regions of axial extension, in which the transport belts 21 are positioned and at least partially wrap the folding roller, a groove 13 each is present.
(15) The low thickness of the transport belts 21 and the stiffness in the radial direction of the folding roller 10 resulting from this produces a low flexibility or elasticity so that the roller nip 15 has to be exactly adjusted to the respective thickness of the product to be folded. The dimension for the roller nip 15 approximately corresponds to the thickness of the finished folded product, which is obtained from the number of the substrate layers and the thickness of the substrate.
(16) However, the adjustment of the roller nip 15 also depends on the shell surface condition of the folding roller 10, of the transport belts 21 but also of the shell surface and of the friction characteristic of the substrate. Accordingly, when adjusting the roller nip 15 appropriate care is required for a roller nip adjusted too narrowly results in damage of the product to be folded such as marks, abrasion or even transverse folds. In an extreme case, the product to be folded is not pulled through the folding roller nip and remains on the folding table 4 of the folding device 1 resulting in so-called stoppers. Furthermore, an adjustment of the roller nip 15 that is too narrow results in increased wear of the transport belts 21, of the folding knife 3 or even of the folding rollers 10. With a folding roller nip 15 that is adjusted too large, the product to be folded is not gripped by the folding rollers 10 or the transport belts 21 and is likewise not reliably pulled through the roller nip 15, which can likewise result in stoppers and thus production interferences.
(17) With the folding rollers 10 known from the prior art, the transport belts 21 are subjected to wear as a result of which on the one hand the friction coefficient of the transport belts 21 and on the other hand the folding away-characteristic changes since the wear of the transport belt 21 results in a low protrusion of a transport belt 21 relative to the outer shell surface of the folding roller body 12.
(18) FIG. 4 shows a configuration of a folding roller 10 according to the invention, which in the regions in axial extension, in which the transport belts 21 wrap the folding roller 10 at least partially, at least one rubber-elastic insert 16 is provided on the folding roller 10 in each case. Here, the circumferential grooves 3 in the folding roller body 12 are matched to the thickness of the insert 16 and of the transport belt 21 in the manner that the transport belt has a protrusion of approximately 0.05 to 0.5 mmdependent for example on the elasticity of the insert 16 and for example the friction coefficient of the transport belt 21 employedrelative to the outer shell surface of the folding roller 10. The transport belts 21, in the case of the folding roller 10 according to the invention, no longer run directly on the folding roller body 12, but on the rubber-elastic insert 16. This produces a flexibility of the transport belt 21 in the radial direction of the folding roller 10, which reduces the wear of the transport belts 21 and at the same time renders the adjustment of the folding roller nip 15 no longer so sensitive. Accordingly, the risk of damage to the print products can be reduced and the production safety increased by avoiding stoppers.
(19) Another configuration of the invention which is not shown by the FIG. 4 is that the folding roller 10 according to the invention does not have a rubber-elastic insert 16 in each region in which a transport belt 21 at least partially wraps the folding roller, but a rubber-elastic insert 16 only attached in at least one region in which a transport belt 21 at least partially wraps the folding roller 10.
(20) In the case of the exemplary configuration of a folding roller 10 according to the invention shown in FIG. 4 in the regions of an axial extension, in which a transport belt 21 at least partially wraps the folding roller 10, a circumferential groove 13 is embodied. This circumferential groove 13 in the folding roller body 12 can be embodied as a circumferential insert groove 19 in which the rubber-elastic insert 16 is positioned.
(21) However it is also possible to embody the circumferential groove 13 in the form that the circumferential insert groove 17 is only a part of the circumferential groove 13 and the circumferential groove in addition to the circumferential insert groove 17 has a circumferential transported belt groove 14. In a groove 13 that is embodied offset in such a manner the rubber-elastic insert is positioned in the region of the groove that is radially inside, i.e., in the insert groove 17, whereas the transport belt groove 14 located radially outside serves for guiding a transport belt 21 in the axial direction. In this configuration, the outer shell surface of the folding roller body 12 protrudes over the outer enveloping shell surface of the rubber-elastic insert 16 and the respective transport belt 21 projects into the circumferential groove 13.
(22) In the case of the folding roller 10 shown in FIG. 4, exemplarily four closed rings or rubber-elastic material with circular cross-section are shown as insert 16 for a transport belt 21, which however corresponds only to one embodiment, for as insert 16, an annular structure or any number of annular structures can also be employed in each case.
(23) Furthermore, there are various possibilities when selecting the materials of the inserts 16: accordingly, inserts 16 of compressible material can be employed or incompressible materials can be used for this purpose. The choice of suitable material in this case is based on the one hand on the combination of the materials for transport belts 21, insert 16 and the substrate to be folded as well as the geometry such as for example the cross-section of the insert 16 and of the groove 13. Furthermore, the choice is also dependent on the configuration of the insert 16.
(24) In the shown example of FIG. 4, multiple rings closed as inserts made from rubber-elastic material such as for example NBR-70 or polyurethane are employed. Dependent on the dimensions of the groove 13 and of the transport belt 21 used, a single ring of rubber elastic material can however be used as insert 16. This ring or these rings are pushed onto the folding roller 10 from the face end in the axial direction. In the process, the folding roller 10 need not be removed from the mounting shown in FIG. 4. However, since the inserts 16 are subject to a certain wear a region of limited axial extension is formed as stocking 19 of at least one insert 16 or preferentially of multiple inserts 16 on the folding roller 10 which preferentially does not come into contact with the product to be folded during the folding operation. This stocking 19 of inserts 16 has the advantage that in the case of wear of the insert 16 and thus for the replacement of the same, the folding roller 10 does not have to be removed from the mounting shown since for replacing an insert 16 the same is cut openif this is still required, so that the worn insert 16 can be removed, a new insert 16 is pushed in the axial direction of the folding roller 10 into the appropriate position in a groove 13 from the region of the stocking 19 of inserts 16.
(25) In a further advantageous embodiment of the invention which is not shown, multiple regions formed as stocking 19 can also be embodied in axial extension of the folding roller 10.
(26) FIG. 5 shows an embodiment in which the transport belt 21 lies on an insert 16 over the entire width. To neatly position or guide insert 16 and transport belt 21, the groove 13 is advantageously embodied in an offset manner. Accordingly, the groove 13 consists of a transport belt groove 14 located as seen in the radial direction on the outside and an insert groove 17 located as seen in the radial direction further inside. However, such an embodiment is not absolutely necessary provided the transport belt 21 is otherwise guided in the correct axial position.
(27) While FIG. 5a shows inserts 16 with circular cross-section, inserts 16 with polygonal cross-section are shown for example in FIG. 5b. This example illustrates that as insert 16 rings with different cross-sections can be employed. This increases the choice of commercially available rings or rubber-elastic material which preferentially have a hardness of approximately 25 to approximately 100 shore.
(28) While in FIGS. 5a and 5b inserts 16 of closed, in other words endless rings are shown, an embodiment of an insert 16 is exemplarily shown in FIG. 5c which can also be produced from a strip of rubber-elastic material with finite extension. The reason is that such a configuration of an insert 16 has the advantage that for replacing the insert 16 the folding roller 10 need not be removed from the shown mounting since such an insert 16 can be applied onto the folding roller 10 in the radial direction from the outside. Preferentially, the strip-shaped insert 16 of FIG. 5c has a length which corresponds to the circumference of the neutral fiber in the assembled state on the folding roller 10. Accordingly, the insert 16 in this configuration has a joint seen in the circumferential direction but this is not a disadvantage in the case of clocked folding rollers.
(29) Advantageously, the insert groove 17 in this configuration of the insert 16 is configured in such a manner that for clamping the rubber-elastic insert 16 additional fixing elements can be omitted. This is achieved for example in that the circumferential insert groove 17 for receiving the insert 16 has a cross-section which, seen in the radial direction, has a cross-section diminishing towards the outside, which for example can have a trapezium-like shape. Preferably, but not absolutely necessarily, compressible materials such as for example foamed polyurethanes are employed with such a configuration of the insert 16.
(30) Alternatively, to ensure the fixed position of the insert 16 on the folding roller 10, an additional fixing element such as for example an adhesive substance can also be employed.
(31) FIGS. 6a, 6b and 6c show a configuration of the invention in which a transport belt 21 over its width lies only partially on a respective insert 16. Such a configuration has the advantage that by neatly demarcating the transport belt groove 14 and the insert groove 17 optimal guidance of the transport belt 21 is ensured.
(32) FIGS. 7a, 7b and 7c show an embodiment in which a transport belt 21 over its width lies on a rubber-elastic insert 16 with merely a relatively small portion. Through this variation of the width of the insert 16, the resilience and thus the elasticity of the insert 16 can be varied with the same material or with the same commercially available rings employed. Thus, it is either possible for different products to be folded, i.e., for example for folding products from different materials or for example for products to be folded of different thickness, to use or provide different types of folding rollers 10 with inserts 16 of different width thereby with different elasticity without having to stock different rings as wear parts.
(33) A particular configuration of the folding roller 10 according to the invention is using inserts 16 of different width in axial extension of the folding roller 10, which in particular seen in axial extension of the folding roller is advantageous in the case of asymmetrical folding products.
(34) As is evident from FIGS. 5 to 7, a combination of different folding rollers 10 with different inserts 16 or even the combination of folding rollers 10 with inserts 16 and folding rollers 10 without inserts is likewise possible and advantageous in particular dependent on the peripheral parameters of the product to be folded.
(35) FIG. 8 shows a further advantageous form of a folding roller 10 according to the invention in which in addition to the insert or inserts 16 in first regions 16 in axial extension, on which the transport belts 21 at least partially wrap the folding roller 10 and which have a circumferential groove 13 and an insert 16 introduced therein, a second region 16 is provided on the folding roller 10, which likewise has a circumferential groove 13 with an insert 16 introduced therein. Advantageously, but not absolutely necessarily, the inserts of the second regions 16 are arranged in relative proximity next to the inserts of the first regions 16. The distance however should be configured at least in such a manner that in the first region 16 and in the second region 16 transport belts 21 can run simultaneously in order to ensure an adequate distance of the first regions 16 from the second regions 16. This configuration offers the advantage that in the case of a worn insert in a first region 16 the relative transport belt 21 only has to be repositioned laterally into the relevant second region 16 so that the maintenance efforts are thereby additionally minimized and the availability additionally increased, in particular when this embodiment is embodied combined with the stocking 19 of inserts 16. A requirement of this embodiment is that the two transport belts 21 of both folding rollers 10 corresponding in axial extension are relocated from a first region 16 into a second region 16 or vice versa and the belt line 20 for avoiding the lateral runoff in the region downstream of the folding rollers 10 next to guide elements in alignment with the first regions 16 have additional guide elements aligned with the second regions 16.
(36) A particularly advantageous configuration of the invention is that the width and/or the elasticity of the insert of the first regions 16 differs from the width and/or the elasticity of the insert of the second regions 16 since because of this embodiment of the folding roller 10 according to the invention the elasticity and thus the folding or conveying behavior of the folding rollers 10 can be exclusively adapted to the respective substrate or the product to be folded by laterally repositioning the transport belts 21 and thus without replacing the folding roller 10 or the inserts 16.
LIST OF REFERENCE NUMBERS
(37) 1 Folding device 2 Folding drum 3 Folding knife 4 Folding table 10 Folding roller 11 Axis of rotation 12 Folding roller body 13 Groove 14 Transport belt groove 15 Roller nip 16 Insert 16 First region 16 Second region 17 Insert groove 18 Projection transport belt 19 Stocking 20 Belt line 21 Transport belt 30 Paddle wheel 31 Delivery belt
(38) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
