DEVICE AND METHOD FOR FOLDING SHEETS

Abstract

A folding unit has two folding rollers with a common folding nip. A first insertion slot has a first insertion plane for a selectively insertable buckle plate and is configured so that a buckle plate mouth of the buckle plate is at an inlet side of the folding nip. A second insertion slot has a second insertion plane for a buckle plate. The second insertion plane is inclined with respect to the first insertion plane and the second insertion slot is designed for the buckle plate mouth of the selectively inserted buckle plate to be arranged on the inlet side of the folding nip. Printing substrates with different properties are processed in a high-quality and highly productive manner in a pocket folding process, especially in buckle folding units of industrial folding machines.

Claims

1. A device for folding sheets, comprising two folding rollers (20, 21) with a common folding nip (23) which has an inlet side (24) and an outlet side (25), comprising a first insertion slot (30) with a first insertion plane (31) for a selectively insertable folding pocket (40) having a folding pocket mouth (41), wherein the first insertion slot (30) is designed such that the folding pocket mouth (41) of the selectively inserted folding pocket (40) is arranged on the inlet side (24) of the folding nip (23), and comprising a second insertion slot (32) with a second insertion plane (33) for a selectively insertable folding pocket (40) having a folding pocket mouth (41), wherein the second insertion plane (33) is formed with an inclination (a) with respect to the first insertion plane (31), and wherein the second insertion slot (32) is designed such that the folding pocket mouth (41) of the selectively inserted folding pocket (40) is arranged on the inlet side (24) of the folding nip (23).

2. The device as claimed in claim 1, wherein the selectively insertable folding pocket (40) is arranged either in the first insertion slot (30) or in the second insertion slot (32).

3. The device as claimed in claim 1 or 2, wherein the device (1) comprises a roller frame (10) with the two folding rollers (21, 22) and at least two further folding rollers (22).

4. The device as claimed in claim 3, wherein the device (1) comprises at least one insertion slot (34) on a first side (13) of the roller frame (10) and at least one insertion slot (30, 36) on the opposite second side (14) of the roller frame (10).

5. The device as claimed in claim 4, wherein the insertion slots (34, 36), or the insertion planes (35, 37) thereof, are formed without an inclination with respect to the first insertion plane (31).

6. The device as claimed in any of the preceding claims 3 to 5, wherein the device (1) comprises insertion slots (30, 32, 34, 36) that follow one another at positions P1 to Pn in the transport direction (2) of the sheets (3) through the roller frame (10), wherein n2 and wherein odd n are located on the first side (13) and even n are located on the second side (14), and wherein the first insertion slot (30) and the second insertion slot (32) are located at position P2.

7. The device as claimed in claim 6, wherein selectively a sheet diverter (43) is arranged in or next to an insertion slot (34) at position P1.

8. The device as claimed in either of the preceding claims 6 and 7, wherein the selectively insertable folding pocket (40) is arranged in the second insertion slot (32) at position P2, and wherein selectively no folding pocket(s) is/are arranged in the further insertion slot (36) or in the further insertion slots (36) on the second side (14), i.e. at least at position P4.

9. The device as claimed in claim 8, wherein selectively a sheet diverter (43) or sheet diverters (43) is/are arranged in the further insertion slot (36) or in the further insertion slots (36) on the second side (14).

10. The device as claimed in claim 9, wherein at least two sheet diverters (43) are coupled together (44) such that they are jointly insertable into and removable from the device (1).

11. The device as claimed in any of the preceding claims 6 to 10, wherein the further position or the further positions on the second side (14), i.e. at least position P4, comprise(s) a respective further insertion slot (36) with a respective further insertion plane (37), and wherein these further insertion planes (37) are each formed with an inclination (1) with respect to the first insertion plane (31).

12. The device as claimed in claim 11, wherein these further insertion planes (37) are each formed with an identical inclination (1) compared with the second insertion plane (33).

13. The device as claimed in claim 11, wherein these further insertion planes (37) are each formed with a different inclination (1) compared with the second insertion plane (33).

14. The device as claimed in any of the preceding claims 6 to 13, wherein the further position or the further positions on the first side (13), i.e. at least position P1, comprise a respective further insertion slot (34) with a respective further insertion plane (35), and wherein these further insertion planes (35) are each formed with an inclination (2) with respect to the first insertion plane (31).

15. The device as claimed in claim 14, wherein these further insertion planes (35) are each formed with an identical inclination (2) compared with the second insertion plane (33).

16. The device as claimed in claim 14, wherein these further insertion planes (35) are each formed with a different inclination (2) compared with the second insertion plane (33).

17. A method for folding sheets, wherein a device (1) as claimed in any of the preceding claims is used, wherein, for a first folding task, the selectively insertable folding pocket (40) is inserted into the first insertion slot (30), and wherein, for a second folding task, the selectively insertable folding pocket (40) is inserted into the second insertion slot (32).

18. The method as claimed in claim 17, wherein the sheets (3) are fed to the device (1) in an overlapping stream, and wherein a first sheet (6) emerges at least from one folding pocket (40), while a subsequent second sheet (4) enters the folding pocket.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0041] FIGS. 1 and 2 show a schematic illustration of a sectional view of the same device according to the prior art.

[0042] FIGS. 3 to 6 are schematic illustrations, each showing a sectional view of a preferred exemplary embodiment of the device according to the invention.

[0043] Mutually corresponding features are identified with the same reference signs throughout the figures. Reference signs that repeat in the figures have partially been omitted for the sake of clarity.

DETAILED DESCRIPTION OF THE INVENTION

[0044] Referring now to the figures of the drawing in detail, it should be noted that the technical features shown in FIGS. 1 and 2 are preferably also present in the respective exemplary embodiments of the device according to the invention shown in FIGS. 3 to 6. For this reason they will not be explained again in detail there.

[0045] FIG. 1 shows a device 1 having a transport and processing direction 2 for sheets 3 to be processed, i.e. to be folded. The sheets are preferably fed to the device 1 as an overlapping stream. The device 1 comprises a folding roller frame 10 having a plurality of folding rollers 11 that are arranged in succession. Each of the rollers 11 has an axis of rotation 12. The folding roller frame 10 defines a first side 13 (for example on the left in the figure) and a second side 14 (for example on the right in the figure). The connecting lines 15 between the axes of rotation 12 form a zigzag arrangement 16. The device 1 is preferably part of a folding machine 50 or of a folding unit 51.

[0046] FIG. 1 shows a first folding roller 20, a second folding roller 21 arranged downstream thereof, and further folding rollers 22 of the folding roller frame 10. The first folding roller 20 and the second folding roller 21 form a folding nip 23, as do respective pairs of the further folding rollers. The folding nip 23 defines an inlet side 24 and an outlet side 25, wherein a sheet 3 to be folded enters the folding nip 23 on the inlet side 24 and emerges therefrom again on the opposite outlet side 25 of the folding nip 23. The folding roller frame 10 also comprises an upstream roller 26.

[0047] FIG. 2 shows on the second side 14 a first insertion slot 30 with a first insertion plane 31, and further insertion slots 34 with further insertion planes 35 on the first side 13 and further insertion slots 36 with further insertion planes 37 on the second side 14. A buckle plate 40, also referred to as a buckle plate 40, having a buckle plate mouth 41 for a specific folding task can be selectively inserted into each insertion slot and removed therefrom again (direction 60), wherein the buckle plate mouth 41 is positioned in each case in the vicinity of a folding nip. Via the buckle plate mouth 41, a sheet 3 to be folded enters the respective buckle plate and emerges therefrom again. Each buckle plate 40 preferably has an adjustable buckle plate stop 42. The insertion slots may be located at the consecutively numbered positions P1 to P6, which correspond to respective folding nips. In FIG. 1, all six illustrated insertion slots, or all six positions P1 to P6, are equipped with buckle plates 40. In FIG. 2, only two insertion slots at the positions P2 and P3 are equipped with buckle plates 40; at the remaining positions P1 and P4 to P6, sheet diverters 43 are arranged instead.

[0048] FIG. 1 shows (only partially for illustration reasons) a sheet 4 entering a buckle plate 40 with a portion 5 and a sheet 6 emerging from the same buckle plate 40 with a portion 7, wherein the portions 5 and 7 pass one another in the case of overlapping folding. In order that no printing substrate-specific problems arise during this process, in particular when successive sheets 3 pass one another, an inclined, second insertion slot is additionally provided according to the invention. This and further inclined insertion slots are explained in the following figures.

[0049] It is apparent from FIG. 3 that, in addition to the first insertion slot 30 with the first insertion plane 31 in position P2, there is a second insertion slot 32 with a second insertion plane 33 in position P2. The second insertion slot 33 is in this case inclined at the angle with respect to the first insertion plane 31 (inclined downwardly by way of example in the illustration), preferably at approximately 17.

[0050] It is apparent from FIG. 4 that a buckle plate 40 having a buckle plate mouth 41 has been selectively inserted into the second insertion slot 32 for a specific folding task. Furthermore, a buckle plate 40 has also been inserted in position P3 for the specific folding task, while there are selectively no buckle plates in the further insertion slots for the specific folding task, there selectively being sheet diverters 43 there instead. The two sheet diverters at positions P4 and P6 are in this case connected mechanically together via a coupler 44 and can in this way be introduced and removed again together.

[0051] It should be noted here that the insertion slots and the buckle plates in actual folding devices are usually longer than illustrated, and that therefore the inclined insertion slot 30 and the inclined buckle plate 40 in position P2 may cross the insertion slots 36 in the positions P4 and P6. In such a case, there may be no buckle plates 40 in the positions P4 and P6 when there is a buckle plate 40 in the inclined insertion slot 32 in position P2.

[0052] It is apparent from FIG. 5 that there may also be inclined insertion slots 36 with inclined insertion planes 37 in positions P4 and P6in addition to the non-inclined insertion slots located there. In this case, the inclination 1 may be identical to, or different from, the inclination . Furthermore, it is apparent from FIG. 6 that there may also be inclined insertion slots 34 with inclined insertion planes 35 on the opposite side in the positions P1, P3 and P5. In this case, the inclination 2 and/or 3 may be identical to or different than the inclination and/or 1. If there are a plurality of insertion slots on one of the two sides 13 and 14, they may in particular be parallel to one another.

[0053] Provision may be made for the folding rollers 17 illustrated in FIG. 4 (all three of them or only the two upper ones) to be arranged in a manner offset upward by a few millimeters compared with the arrangement in FIG. 1, i.e. preferably as early as during assembly and permanently. Or put another way: the group of the two or three folding rollers 17 exhibits a spacing with respect to the group of the further folding rollers of the roller frame, this differing from, and preferably being greater than, the spacing of the respective folding rollers from one another. As a result, the angle at which a sheet 3 to be folded enters the inclined buckle plate 40 advantageously changes, as does the angle at which it emerges therefrom again.

[0054] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0055] 1 Device [0056] 2 Transport direction [0057] 3 Sheet, (overlapping) stream of sheets [0058] 4 Entering sheet [0059] 5 Portion of the entering sheet [0060] 6 Emerging sheet [0061] 7 Portion of the emerging sheet [0062] 8 Folding roller frame [0063] 11 Folding rollers [0064] 12 Axes of rotation of the folding rollers [0065] 13 First side [0066] 14 Second side [0067] 15 Connecting lines [0068] 16 Zigzag arrangement or zigzag line [0069] 17 Folding rollers [0070] 18 First folding roller [0071] 21 Second folding roller [0072] 22 Further folding rollers [0073] 23 Folding nip(s) [0074] 24 Inlet side of the folding nip [0075] 25 Outlet side of the folding nip [0076] 26 Upstream roller [0077] 30 First insertion slot [0078] 31 First insertion plane [0079] 32 Second insertion slot [0080] 33 Second insertion plane [0081] 34 Further insertion slot(s) on the first side [0082] 35 Further insertion plane(s) [0083] 36 Further insertion slot(s) on the second side [0084] 37 Further insertion plane(s) [0085] 40 Buckle plate(s), Folding pocket(s) [0086] 41 Buckle plate mouth, folding pocket mouth, mouth [0087] 42 (Adjustable) buckle plate stop, buckle stop [0088] 43 Sheet diverter(s) [0089] 44 Coupler for sheet diverters [0090] 50 Folding machine [0091] 51 Folding unit [0092] 60 Direction on insertion and removal [0093] P1-Pn Positions 1 to n [0094] Inclination(s) or angle(s) [0095] 1 Inclination(s) or angle(s) [0096] 2 Inclination(s) or angle(s) [0097] 3 Inclination(s) or angle(s)