Method for folding sheets of fiber-based material in a folding machine

Abstract

A method according to the invention for folding sheets of fiber-based material in a folding machine, wherein a pocket folding unit (4) with at least one folding pocket (4a) is used, wherein the folding in the pocket folding unit (4) is supported by blowing air (10) and wherein a flow parameter of the blowing air (10) is set depending on the material (22), is characterized in that, for setting the blowing air (10), a test strip (23) of the material (10) is supplied with auxiliary blowing air (11) in an adjustment device (30) and is thereby deformed into a predetermined target shape (26), for which purpose a flow parameter of the auxiliary blowing air (11) is set, and that the flow parameter of the blowing air (10) is set depending on the flow parameter of the auxiliary blowing air (11).The invention advantageously simplifies the necessary adjustments for pneumatically assisted folding in folding pockets, avoids errors, and consequently improves the production of folded products. The invention is used, for example, in folding machines with pocket folding units.

Description

invention

[0001] The invention relates to a method having the features of the preamble of claim 1. field of technology

[0002] The invention lies in the technical field of the graphic industry and there in particular in the area of ​​pocket folding of flexible, sheet-shaped printed materials or the industrial, i.e. high-quality and high-productivity production of folded products such as brochures, preferably made of paper, cardboard, corrugated board, plastic or composite material, in particular of printed paper. State of the art

[0003] Industrial folding machines with preferably multiple folding units (folding stations) for producing folded products from sheet-shaped substrates, for example, paper, and with conveying units for moving the folded products are known in the prior art. The folding units can be, for example, pocket folders and / or blade folders for producing preferably multiple folds. The conveying units can be, for example, roller tables with inclined conveying rollers. Such folding machines also typically include a feeder, e.g., a stack feeder, for the sheets to be folded and a delivery unit for the folded products. The sheets to be folded can preferably be conveyed as a stream and particularly preferably as a shingled stream to the first folding unit. Conveying between the folding units as a so-called shingled stream is also possible in high-end machines. Such folding machines further include a machine control system in the form of a digital computer with control software.Folding in pocket folding machines can be supported and thus improved by blown air.

[0004] DE102004012692A1 discloses a method for folding sheets in a folding machine, wherein a pocket folding unit with at least one folding pocket and several folding rollers is used, wherein the folding in the pocket folding unit is supported by blown air.

[0005] DE102011018859A1 discloses a similar process.

[0006] Such processes are used, for example, in the "Stahlfolder" sheet folding machines from Heidelberger Druckmaschinen AG. Depending on the product being folded, a flow parameter of the blowing air is set based on the product material. The operators have access to setting tables for the various materials to be folded. These tables are complex to create and must be updated for all available materials. The setting process is time-consuming, and errors can occur. Technical task

[0007] It is therefore an object of the present invention to provide an improvement over the prior art which in particular makes it possible to simplify necessary adjustments for air-assisted folding in folding pockets, to avoid errors and consequently to improve the production of folded products. Inventive solution to the problem

[0008] This problem is solved according to the invention by a method according to claim 1.

[0009] A method according to the invention for folding sheets of fiber-based material in a folding machine, wherein a pocket folding unit with at least one folding pocket is used, wherein the folding in the pocket folding unit is supported by blown air and wherein a flow parameter of the blown air is set depending on the material, is characterized in that, for setting the blown air, a test strip of the material is supplied with auxiliary blown air in an setting device and is thereby deformed into a predetermined target shape, for which purpose a flow parameter of the auxiliary blown air is set, and that the flow parameter of the blown air is set depending on the flow parameter of the auxiliary blown air.

[0010] An adjusting device according to the invention for use in one of the preceding methods is characterized in that the adjusting device comprises an auxiliary blowing nozzle for generating the auxiliary blowing air, wherein the auxiliary blowing nozzle is directed towards an area of ​​the test strip.

[0011] A folding machine according to the invention with an adjusting device according to the invention is characterized in that the adjusting device is provided on the folding machine.

[0012] Advantageous and therefore preferred embodiments of the invention are evident from the dependent claims as well as from the description and the drawings. Advantageous forms and effects of the invention

[0013] The invention advantageously simplifies the necessary adjustments for pneumatically assisted folding in folding pockets, avoids errors, and consequently improves the production of folded products. The invention is used, for example, in folding machines with pocket folding units.

[0014] The invention particularly simplifies the adjustment of the blowing air during air-assisted folding in a folding pocket, i.e., for example, the adjustment of the pressure, volume flow, and / or velocity of the blowing air. The adjustment can be made remotely from the installed folding pocket, preferably in an easily accessible area of ​​the folding machine. The adjustment is performed using the same material to be folded. Therefore, materials for which no predefined setting values ​​exist can also be processed optimally.

[0015] The blowing air in the folding machine is preferably perfectly adjusted when the auxiliary blowing air in the adjustment device is also perfectly adjusted, i.e., when the test strip assumes the specified target shape or a corresponding curvature. A test strip made of thicker or less flexible sheet material must be supplied with more auxiliary blowing air to assume the specified target shape than a test strip made of thinner or more flexible sheet material. Therefore, if sheets are to be folded that require, for example, more blowing air for a perfect fold, the test strip made of the same material must also be supplied with more auxiliary blowing air. In this way, the blowing air pressure can be advantageously adjusted away from the folding pocket at a more accessible location using the test strip.

[0016] The feature "that the flow parameter of the blown air is adjusted depending on the flow parameter of the auxiliary blown air" can be realized, for example, by preferably setting both flow parameters identically or substantially identically. This can be implemented technically, for example, by designing the compressed air supply such that the pressure of the blown air at a blown nozzle and at an auxiliary blown nozzle is substantially identical, e.g., by using lines of identical or substantially identical length (with the same cross-sectional area) or by resulting in comparable pressure losses. Alternatively, the feature can be realized by setting both flow parameters proportionally to each other, preferably using a predetermined proportionality factor.

[0017] Adjusting the pressure of the auxiliary blowing air at the auxiliary blowing air nozzle can affect the blowing air pressure at a single folding pocket. However, it may also be possible to adjust multiple folding pockets simultaneously in this way. Ideally, the entire folding process in the blowing air-assisted folding pockets should be calibrated using a test strip. Further developments of the invention

[0018] Preferred embodiments of the invention are described below as methods (hereinafter referred to as embodiments). These can be combined with one another, unless technically impossible.

[0019] Further training can be characterized by the fact that the test strip is cut from the material. The cutting can be done by the operating personnel, e.g., from a waste sheet of the material to be folded. The test strip is preferably cut to a predetermined dimension. It can be provided that the test strip is cut to a predetermined dimension with a length L and a width B, where L1>1*B, L1>2*B, L1>3*B, L1>4*B, or L1>5*B. It can also be provided that the test strip is folded in the middle so that its length is halved to L2=0.5*L1.

[0020] A further development can be characterized by the fact that the test strip is clamped at one end in the setting device. This clamping can be done using a clamping device within the setting device. The clamping device can be an existing paper thickness measuring device or part thereof. Thus, a paper thickness measurement can be performed simultaneously, the result of which can be used for other settings in the folding machine. It can be provided that the test strip is clamped in the setting device with a folded end. It can be provided that at least one opposite, open end protrudes from the setting device. It can be provided that the protruding open end has a length L3 ≥ 0.5 * L2.

[0021] A further development can be characterized by the fact that a movable area of ​​the test strip is supplied with auxiliary blowing air. The movable area is preferably flexible, in particular pliable. It can be provided that the movable area comprises the open end of the test strip.

[0022] A further development process can be characterized by the fact that the movable area is curved under the influence of the auxiliary blowing air. For this purpose, a sufficiently strong force is exerted on the movable area by means of the auxiliary blowing air. It can be provided that the flow parameter of the auxiliary blowing air is changed, i.e., increased or decreased, until a curvature corresponding to the desired shape is achieved. The desired shape or curvature is preferably defined by a correspondingly curved surface. It can be provided that the flow parameter of the auxiliary blowing air is changed by actuating a pressure control regulator, in particular a control valve. Once the desired shape is achieved, the pressure control regulator or the control valve can remain in its position. The setting of the auxiliary blowing air, and thus also the blowing air, is now optimal.

[0023] Further education can be characterized by the fact that the fiber-based material is paper, cardboard or corrugated board.

[0024] Further training can be characterized by the fact that the flow parameter includes a single parameter or several parameters: pressure of the blown air and / or volume flow of the blown air and / or velocity of the blown air.

[0025] Preferred embodiments of the invention as a device (adjusting device) (hereinafter referred to as: embodiments) are described below. These can also be combined with one another, unless technically precluded.

[0026] A further development can be characterized by the fact that the auxiliary blowing nozzle is directed towards the movable area of ​​the test strip, i.e., that the blowing air is directed towards this area, preferably towards a central point of the area. The auxiliary blowing nozzle can be configured to be activated and deactivated. Activation and deactivation can be effected by an activation unit for the auxiliary blowing air, in particular a shut-off valve in an auxiliary blowing air line (alternatively or simply: supply line) to the auxiliary blowing nozzle.

[0027] A further development can be characterized by the fact that a second line branches off from the auxiliary blowing air line to the auxiliary blowing nozzle between the activation unit for the auxiliary blowing air or the shut-off valve and the auxiliary blowing nozzle. This second line leads to a flow compensator. The flow compensator serves to generate a nearly laminar flow of the auxiliary blowing air and to reduce disruptive turbulence, especially when the activation unit is actuated (or when the shut-off valve is opened), thereby directing the auxiliary blowing air jet precisely onto the test strip. The auxiliary blowing air line may branch off from a supply line between a compressed air source and a blowing nozzle strip of an air-assisted folding pocket.

[0028] Preferred embodiments of the invention as a device (folding machine) (hereinafter referred to as "embodiments") are described below. These embodiments can also be combined with one another, unless technically precluded.

[0029] Further training can be characterized by the fact that the adjustment device is provided at an operator-accessible section of the folding machine.

[0030] A further development process can be characterized by the fact that a blower nozzle strip is operated at the folding pocket to expel the blowing air. The blower nozzle strip may comprise a large number of blower nozzles arranged in a row.

[0031] The technical features disclosed in the above sections Technical Field, Invention and Further Developments, as well as in the section Exemplary Embodiments, may represent further advantageous developments of the invention as combinations of features which can be derived from this application. Exemplary embodiments of the invention and figures

[0032] The figures show preferred embodiments of the invention and its further developments. Corresponding features are identified by the same reference numerals in the figures. For clarity, some reference numerals that are repeated in the figures have been omitted. Fig. Figure 1 shows a schematic representation of the structure of a preferred embodiment of an adjustment device according to the invention on a folding machine. Fig. Figure 2 shows a schematic representation of the production of a test strip within the framework of a method according to the invention.

[0033] In Fig. Figure 1 shows a folding machine 1 with a sheet feeder 2 and an operator-accessible section 3. The machine 1 comprises a pocket folding unit 4 with at least one folding pocket 4a and several folding rollers 4b, as well as an adjustable stop 4c for the folding pocket 4a. The folding process in the pocket folding unit 4 is air-assisted, for which a blower nozzle bar 5 with several blower nozzles 6 is provided, which blows air 10 onto each sheet 21 to be folded, thereby ensuring a perfect folding result or a perfect fold 21a.

[0034] An adjustment device 30 according to the invention is provided, and in particular arranged, at the operator-accessible part 3 of the machine 1. The device 30 comprises, as its functionally central element, an auxiliary blowing nozzle 31, which discharges auxiliary blowing air 11 directed onto a test strip 23. The sheets 21 of the sheet stack 20 of the folding machine 1 to be processed are made of material 22, preferably paper, and the test strip 23 is also made of this material.

[0035] In Fig. Figure 2 shows how such a test strip 23 can be produced: A test strip 23 with a predetermined length L1 and a predetermined width B is cut from a sheet 21, for example a waste paper sheet, and then preferably folded in the middle to a length L2. The folded test strip 23 then comprises a folded end 23a and an open end 23b.

[0036] The test strip 23 is preferably inserted into a clamping device 25 with its folded end 23a and clamped there. A movable (flexible, bendable) area 24 of the test strip 23 protrudes from the clamping device 25 and can be deformed, in particular curved, by the auxiliary blowing air 11. A desired shape 26 is predetermined, preferably by a curved surface 27, to which the movable area 24 of the test strip 23 conforms under the influence of the auxiliary blowing air 11 and thereby assumes a predetermined curvature 28.

[0037] The blow nozzles 6 of the folding machine 1 are connected to a compressed air supply: A compressed air source 40 is connected to the blow nozzles 6 via a supply line 41, and the supply line 41 includes a pressure control regulator 42, for example a control valve, and a pressure gauge 43. The pressure of the compressed air 10 can be adjusted at the pressure control regulator 42, for example manually, and read on the pressure gauge 43. In this way, the pressure of the compressed air 10 can be set to a predetermined value, for example to a value from a table containing the pressure values ​​for various materials 22.

[0038] An auxiliary blowing air line 32 branches off from the supply line 41, which serves as a supply line to the auxiliary blowing nozzle 31 and which includes an activation unit 33 for the auxiliary blowing air 11, for example a shut-off valve.

[0039] Furthermore, a second line 34 branches off from line 32, which forms a compensation line 34 and includes a flow compensator 35.

[0040] With the aid of the auxiliary blowing nozzles 31 or the auxiliary blowing air 11 according to the invention, the pressure of the blowing air 10 can be perfectly adjusted even if no pressure value is known for a given material 22, for example, if it is not listed in the table mentioned above. In this way, even new and / or rarely used materials can be folded perfectly.

[0041] The procedure for adjusting the blowing air 10 in the folding machine 1 can include the following steps: • First, a test strip 23 is prepared as described above and inserted into the clamping device 25 and clamped. • Then the activation unit 33 is actuated and thereby activated, so that auxiliary blowing air 11 is directed onto the movable area 24 of the test strip 23. • Then the pressure of the blown air is changed at the pressure adjustment regulator 42, i.e. increased or decreased, until the movable area 24 has assumed the desired shape 26 or the curvature 28. • The activation unit is then activated again and thereby deactivated. • The pressure of the auxiliary blowing air 11 set in this way simultaneously leads to the setting of the pressure of the blowing air 10 in the folding machine 1. The two pressures 10 and 11 are preferably essentially identical. • With the pressure of the blowing air 10 set in this way, the blowing air-assisted folding process can take place in the folding machine 1. • In a subsequent folding process with different sheets 21 or different material 22, the same adjustment process can be carried out in the same way with a new test strip 23. Reference symbol list 1 folding machine 2 investors 3. Operator-accessible section 4 pocket folding mechanism 4a Folding pocket 4b Folding rollers 4c adjustable stop 5 air nozzle strip 6 air nozzles 10 blown air 11 Auxiliary blower air 20 stacks of sheets 21 sheets 21a Fold break 22 Material 23 test strips 23a folded end 23b open end 24 movable area 25 clamping device 26 Target form 27 curved surface 28 Curvature 30 Adjustment device 31 Auxiliary blower nozzle 32 Auxiliary blowing air line (supply line) 33 Activation unit for the auxiliary blowing air, in particular shut-off valve 34 Compensation line (second line) 35 Flow compensator 40 Compressed air source 41 Supply line 42 Pressure adjustment regulators, in particular control valves 43 Pressure gauges L1 length L2 halved length B Width

Claims

[1] Method for folding sheets of fiber-based material in a folding machine, wherein a pocket folding unit (4) with at least one folding pocket (4a) is used, wherein the folding in the pocket folding unit (4) is assisted by blowing air (10) and wherein a flow parameter of the blowing air (10) is set depending on the material (22), characterized by , that to adjust the blowing air (10) a test strip (23) of the material (10) is subjected to auxiliary blowing air (11) in an adjustment device (30) and thereby deformed into a predetermined target shape (26), for which a flow parameter of the auxiliary blowing air (11) is set, and that the flow parameter of the blowing air (10) is set as a function of the flow parameter of the auxiliary blowing air (11). [2] Method according to claim 1, characterized by , that the test strip (23) is clamped with one end (23a) in the adjusting device (30). [3] Method according to claim 2, characterized by, that the test strip (23) is clamped in the adjusting device (30) with a folded end (23a). [4] Method according to claim 3, characterized by , that at least one opposite, open end (23b) protrudes from the adjusting device (30). [5] Method according to claim 4, characterized by , that a movable area (24) of the test strip (23) is supplied with the auxiliary blowing air (11). [6] Method according to claim 5, characterized by , that the movable area (24) is curved under the influence of the auxiliary blowing air (11). [7] Method according to any one of the preceding claims, characterized by , that the flow parameter of the auxiliary blowing air (11) is changed, i.e. increased or decreased, until a curvature (28) specified according to the target shape (26) is achieved. [8] Method according to claim 7, characterized by, that the flow parameter includes a single parameter or several parameters: pressure of the blowing air (10) and / or volume flow of the blowing air (10) and / or velocity of the blowing air (10). [9] Adjustment device for use in one of the preceding methods, characterized by , that the adjusting device (30) comprises an auxiliary blowing nozzle (31) for generating the auxiliary blowing air (11), wherein the auxiliary blowing nozzle (31) is directed towards an area (24) of the test strip (23). [10] Adjustment device according to claim 9, characterized by , that the auxiliary blowing nozzle (31) is directed towards the movable area (31) of the test strip (23). [11] Adjustment device according to claim 10, characterized by , that the auxiliary blower nozzle (31) can be activated and deactivated. [12] Adjustment device according to one of claims 10 or 11, characterized by, that on the auxiliary blowing air line (32) to the auxiliary blowing nozzle (31) between an activation unit (33) for the auxiliary blowing air (11) and the auxiliary blowing nozzle (31) a second line (34) branches off as a compensation line (34) and that the second line (34) leads to a flow compensator (35). [13] Adjustment device according to one of claims 10, 11 or 12, characterized by , that the auxiliary blowing air line (32) branches off from a supply line (41) between a compressed air source (40) and a blowing nozzle strip (5) of a blowing air-assisted folding pocket (4a). [14] Folding machine with an adjustment device according to one of claims 9 to 13, characterized by , that the adjusting device (30) is provided on the folding machine (1). [15] Folding machine according to claim 14, characterized by , that the adjusting device (30) is provided at an operator-accessible section (3) of the folding machine (1).

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