Apparatus and method for positionally defined transport of sheets

Abstract

The invention relates to an apparatus, in particular a roll cross cutter, for forming a shingled stream of underlapping or overlapping sheets, in particular paper or cardboard sheets, comprising a transport device for transporting sheets, a shingling device for underlapping or overlapping of the sheets at least in some regions, a braking device following the shingling device in the transport direction of the sheets for braking of shingled sheets, in particular by the formation of a brake gap for the passage of sheets brought together in a shingled manner, and a cross-cutting device upstream of the shingling device for cutting a material strip into individual sheets. According to the invention, an intake section is provided between the shingling device and the braking device for intake and further transport of a sheet, trailing in the shingled stream, into the braking device.

Claims

1. An apparatus, in particular roll-type cross-cutter, for forming a shingled stream of underlapping or overlapping sheets, in particular paper or cardboard sheets, the apparatus having: a transport device for transporting sheets; a shingling device for underlapping or overlapping the sheets in regions; a braking device which is situated downstream of the shingling device in a transport direction of the sheets and which serves for braking shingled sheets, in particular by forming a braking gap for the passage of sheets that have been brought together in shingled form; a cross-cutting device which is positioned upstream of the shingling device and which serves for cutting a material strip into individual sheets; a first suction intake section provided upstream of the shingling device and extending between the cross-cutting device and the shingling device; and a second suction intake section provided upstream of the braking device and extending between the shingling device and the braking device and which serves for sucking up and further transporting a trailing sheet in the shingled stream into the braking device; wherein between the first suction intake section and the second suction intake section and directly below the shingling device, a portion of a transport plane of the sheets is provided with no negative pressure or a less strong negative pressure in comparison to a negative pressure generated by the first and second suction intake sections.

2. The apparatus as claimed in claim 1, wherein a pressure level in the region of the second suction intake section is reduced less severely than in the region of the first suction intake section.

3. The apparatus as claimed in claim 1, wherein the shingling device is designed to be adjustable in and/or counter to the transport direction of the sheets in a manner dependent on a cut length.

4. The apparatus as claimed in claim 1, wherein the transport device has at least one suction belt, in particular a belt arrangement having a plurality of suction belts running parallel to one another; and wherein the at least one suction belt is guided continuously in the transport direction of the sheets over the first and second suction intake sections and the portion of the transport plane of the sheets directly below the shingling device.

5. The apparatus as claimed in claim 1, wherein at least one suction intake device is provided for forming the first suction intake section; and wherein the suction intake device has a suction profile or a suction box and/or is connected thereto.

6. The apparatus as claimed in claim 1, wherein at least one continuous suction profile is provided, in particular an arrangement of a plurality of suction profiles lying one behind another transversely with respect to the transport direction of the sheets, or a continuous suction box is provided for reducing the pressure and forming the first and second suction intake sections.

7. The apparatus as claimed in claim 6, wherein a non-continuous decrease in the reduction in pressure in the portion of the transport plane of the sheets directly below the shingling device is provided over the length of the suction profile or suction box; wherein, preferably, the suction profile or the suction box has a lock which is movable in and/or counter to the transport direction of the sheets and serves for forming the non-continuous decrease in the reduction in pressure; and wherein, furthermore preferably, the movable lock is designed to be adjustable together with the shingling device in and/or counter to the transport direction of the sheets.

8. A method for forming a shingled stream of underlapping or overlapping sheets, in particular paper or cardboard sheets, furthermore in particular for forming a shingled stream of individual sheets cut from a material strip by means of a cross-cutting device, wherein separated sheets are transported to a shingling device and are underlapped or overlapped in regions in order to generate a shingled stream; wherein the shingled sheets are braked by means of a braking device which is situated downstream of the shingling device in a transport direction of the sheets, in particular carried out with an apparatus as claimed in claim 1; and wherein a trailing sheets of the shingled stream is transported into the braking device under the action of intake suction.

9. An apparatus, in particular roll type cross cutter, for forming a shingled stream of underlapping or overlapping sheets, in particular paper or cardboard sheets, the apparatus having: a transport device for transporting sheets; a shingling device for underlapping or overlapping the sheets in regions; a braking device which is situated downstream of the shingling device in a transport direction of the sheets and which serves for braking shingled sheets, in particular by forming a braking gap for the passage of sheets that have been brought together in shingled form; a cross-cutting device which is positioned upstream of the shingling device and which serves for cutting a material strip into individual sheets; a first suction intake section provided upstream of the shingling device and extending from the cross-cutting device to the shingling device; and a second suction intake section provided upstream of the braking device and extending from the shingling device to the braking device and which serves for sucking up and further transporting a trailing sheet in the shingled stream into the braking device; wherein a magnitude of a vacuum generated in the region of the second suction intake section is less than a magnitude of a vacuum generated in the region of the first suction intake section.

10. The apparatus as claimed in claim 9, wherein the second suction intake section and the first suction intake section are interrupted directly below the shingling device.

11. The apparatus as claimed in claim 9, wherein the shingling device is designed to be adjustable in and/or counter to the transport direction of the sheets in a manner dependent on a cut length.

12. The apparatus as claimed in claim 9, wherein the transport device has at least one suction belt, in particular a belt arrangement having a plurality of suction belts running parallel to one another; and wherein the at least one suction belt is guided continuously in the transport direction of the sheets over the first and second suction intake sections and directly below the shingling device.

13. The apparatus as claimed in claim 9, wherein at least one suction intake device is provided for forming the first suction intake section; and wherein the suction intake device has a suction profile or a suction box and/or is connected thereto.

14. The apparatus as claimed in claim 9, wherein at least one continuous suction profile is provided, in particular an arrangement of a plurality of suction profiles lying one behind another transversely with respect to the transport direction of the sheets, or a continuous suction box is provided for generating the vacuum and forming the first and second suction intake sections.

15. The apparatus as claimed in claim 14, wherein a non-continuous decrease in the magnitude of the vacuum directly below the shingling device is provided over the length of the suction profile or suction box; wherein, preferably, the suction profile or the suction box has a lock which is movable in and/or counter to the transport direction of the sheets and serves for forming the non-continuous decrease in the magnitude of the vacuum; and wherein, furthermore preferably, the movable lock is designed to be adjustable together with the shingling device in and/or counter to the transport direction of the sheets.

16. A method for forming a shingled stream of underlapping or overlapping sheets, in particular paper or cardboard sheets, furthermore in particular for forming a shingled stream of individual sheets cut from a material strip by means of a cross-cutting device, wherein separated sheets are transported to a shingling device and are underlapped or overlapped in regions in order to generate a shingled stream; wherein the shingled sheets are braked by means of a braking device which is situated downstream of the shingling device in a transport direction of the sheets, in particular carried out with an apparatus as claimed in claim 9; and wherein a trailing sheets of the shingled stream is transported into the braking device under the action of intake suction.

17. The apparatus as claimed in claim 1, wherein at the portion of the transport plane of the sheets that is provided with no negative pressure or the less strong negative pressure, a significantly reduced suction force, if any at all, acts on a rear edge of the trailing sheet.

18. The apparatus as claimed in claim 6, wherein a non-continuous decrease in the reduction in pressure in the portion of the transport plane of the sheets directly below the shingling device is provided over the length of the suction profile or suction box.

19. The apparatus as claimed in claim 18, wherein the suction profile or the suction box has a lock which is movable in and/or counter to the transport direction of the sheets and serves for forming the non-continuous decrease in the reduction in pressure.

20. The apparatus as claimed in claim 14, wherein a non-continuous decrease in the magnitude of the vacuum directly below the shingling device is provided over the length of the suction profile or suction box.

21. The apparatus as claimed in claim 20, wherein the suction profile or the suction box has a lock which is movable in and/or counter to the transport direction of the sheets and serves for forming the non-continuous decrease in the magnitude of the vacuum.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in more detail below with reference to the figures, in which

(2) FIG. 1 shows a schematic illustration of an apparatus for forming a shingled stream of underlapping sheets according to the prior art in a side view,

(3) FIG. 2 shows a schematic illustration of an apparatus according to the invention for forming a shingled stream of underlapping sheets in the operating state in a side view,

(4) FIG. 3 shows a schematic illustration of a further embodiment of an apparatus according to the invention for forming a shingled stream of underlapping sheets in the operating state in a side view, and

(5) FIG. 4 shows a schematic illustration of a further embodiment of an apparatus according to the invention for forming a shingled stream of underlapping sheets in the operating state in a side view.

DETAILED DESCRIPTION

(6) FIG. 1 schematically shows an apparatus 1 known from the prior art for forming a sheet stream 2 of underlapping sheets 3 of paper, foil or cardboard. The apparatus 1 has a feed device (not illustrated) which conveys a virtually endless paper or cardboard strip 4. The strip is provided from a paper or paperboard roll on a feed side by means of an unrolling device (not illustrated) and can be guided through a paper store connected in between. A cross-cutting device 5 positioned downstream of the feed device (not illustrated) in a transport direction X of the sheets 3 cuts the strip 4 into sheets 3 of a defined length. The cross-cutting device 5 is designed in the form of a rotatably mounted shaft 6 which, on its circumference, has a cutting edge 7. If the cutting edge 7 arranged on the shaft 6 and a fixed cutting edge 8 are in engagement, the strip 4 is cut. The sheet length can be set by changing the rotational speed of the shaft 6 and by the feed speed.

(7) The sheets 3 are transported onward in the transport direction X on a belt section with at least one fast-running transport belt 9. A belt section having a plurality of transport belts 9 is preferably provided, the transport belts lying one behind another and being spaced apart from one another transversely with respect to the transport direction X. The following explanations with regard to the transport belt 9 refer to said belt section.

(8) A shingling device 10 situated downstream of the cross-cutting device 5 consists of a raising unit 11 and a decelerating unit 12. The decelerating unit 12 has at least one suction belt 13 arranged above the transport plane Y of the sheets 3. The suction belt 13 is formed by a transport belt which is provided with holes and which interacts with a vacuum-generating suction box 14. The raising unit 11 has a beater shaft 15 with at least one beater 16. The beater 16 of the raising unit 11, during each revolution of the beater shaft 15, presses a sheet 3 against the suction belt 13. Since the suction belt 13 is moved at a lower speed than the fast-running transport belt 9, the front edge of a trailing sheet 3 is conveyed under the raised rear edge of a leading sheet 3. With the next revolution of the beater shaft 16, the trailing sheet 3 is raised at the rear edge such that the next trailing sheet 3 can be conveyed under the trailing sheet 3. In this way, a sheet stream 2 of underlapping sheets 3 is generated. When the rear edge of the leading sheet 3 is no longer situated in the engagement region of the suction belt 13, the leading sheet 3 is held above the transport plane by the trailing sheet 3 since the trailing sheet 3 is already held up by the suction belt 13 before the leading sheet 3 leaves the engagement region of the suction belt 13.

(9) A braking device 17 is provided downstream of the shingling device 10 in the transport direction X of the sheet stream 2. The braking device 17 has at least one nip roll 18 which, together with at least one slow-running transport belt 19, forms a braking gap. The spacing between the braking device 17 and the shingling device 10 is set such that the sheet front edge of a sheet 3 preferably runs straight into the braking gap, and is decelerated, just as the rear sheet region, in particular the rear edge of the sheet 3, is pressed by the beater 16 of the raising unit 11 against the suction belt 13. The sheet 3 is thereby braked or decelerated preferably approximately simultaneously by the nip roll 18 and by the slow-running transport belt 19 in the front region and by the suction belt 13 in the rear sheet region. In order to tension the sheet and to reduce sagging of the sheet, the suction belt 13 has a slightly reduced speed in comparison to the slow-running transport belt 19. Following the braking device 17, the sheet stream 2 is transported onward at the same speed, and in particular with substantially the same shingling length, i.e. with a same spacing from the front edge of the leading sheet 3 to the front edge of the trailing sheet 3, on a transfer table (not illustrated) to a transfer point (not illustrated) of a further-processing machine.

(10) In the region between the cross-cutting device 5 and the shingling device 10, a suction box 20 can be arranged below the transport belt 9. The transport belt 9 is then preferably designed as a suction belt. A negative pressure is generated in the suction box 20, as a result of which the sheets are pulled against the transport belt 9. By this means, the sheet 3 or the material web 4 is transported on the transport belt 9 before, during and after cutting in the cross-cutting device 5.

(11) As can be seen in FIG. 1, the braking device 17 is designed to be adjustable in and/or counter to the transport direction X of the sheets 3. This is illustrated by the double arrow 21. If the apparatus 1 is changed to a different sheet format, the braking device 17 is adjusted in such a manner that the spacing between the braking device 17 and the shingling device 10 substantially corresponds to the sheet length of the new sheet format. The spacing between the braking device 17 and the shingling device 10 is intended to be set in such a manner that the sheet 3 is braked substantially simultaneously at its front edge by the braking device 17 and at its rear edge by the suction belt 13 of the shingling device 10.

(12) The shingling device 10 can then be moved, offset or displaced relative to the braking device 17 in or counter to the transport direction of the sheets 3 depending on the current (new) sheet length, and therefore, for each sheet length which can be set, a leading sheet 3 is braked approximately simultaneously at the front by the braking device 17 and at the rear by the shingling device 10. In particular, it is made possible to keep the spacing between the transfer point and the braking device 17 or the transfer length in the event of a format change constant, wherein the braking device 17 is preferably not adjusted in the event of a format change. Instead, the spacing between the braking device 17, which is preferably arranged in a fixed position, and the shingling device 10 is adapted to the actual sheet length by adjustment of the shingling device 10. The spacing between the front transfer point of the sheets 3 to a sheet-processing machine and the braking device 17 or the transfer length thus remains the same for different formats or cut lengths, which leads to a considerable simplification in the setting of the apparatus to a different sheet format. In particular, when the transfer length remains the same, it is unnecessary to change the overlapping length of the sheets 3 in the shingled stream in the event of a format change.

(13) It has been shown in the case of the apparatus 1 illustrated in FIG. 1 that the transport of the sheet front edge of the sheet 3 between the shingling device 10 and the braking device 17 is susceptible to faults. The front edge of the sheet 3, in particular at high transport speeds, may thus become detached from the fast-running transport belt 9. Detaching of the sheet front edge from the transport belt 9 may cause the sheet 3 to be damaged as it enters the braking gap of the braking device 17. Furthermore, detaching of the sheet front edge can cause the sheet 3 to be brought out of its position, and therefore, subsequently, an inexact shingling length is formed between the front edge of the leading sheet 3 and the front edge of the trailing sheet 3. Furthermore, during the detaching from the fast-running transport belt 9 or by means of slipping, the sheet front edge can enter into frictional contact with the leading sheet 3. The sheet 3 can thereby be additionally braked, and therefore the desired shingling length is likewise not reached.

(14) FIG. 2 shows schematically another apparatus 1 for forming a shingled stream 2 of underlapping sheets 3 in a side view. Identical or corresponding functional units, assemblies, components and other corresponding features of the apparatus 1 shown in FIGS. 1 and 2 are provided with the same reference signs. The formation of a shingled stream 2 of underlapping sheets 3 from paper, foil or cardboard takes place, in the embodiment shown in FIG. 2, in a corresponding manner to the above-described formation of a shingled stream in the apparatus 1 from FIG. 1.

(15) In a departure from the apparatus 1 shown in FIG. 1, in the embodiment according to FIG. 2 it is provided that the shingling device 10 is designed to be adjustable in and/or counter to the transport direction X depending on the sheet length or the sheet format. This is shown schematically in FIG. 2 by the double arrow 21. By contrast, the braking device 17 is designed to be non-adjustable in and/or counter to the transport direction X of the sheets 3. In other words, this means that the shingling device 10, when the cut length of the sheets 3 is changed or when there is a change in the sheet format, the shingling device 10 is offset, displaced or moved relative to the braking device 17 in such a manner that, for each sheet length set, a leading sheet 3 is braked approximately simultaneously at the front by the braking device 17 and at the rear by the deceleration unit 12 of the shingling device 10. The spacing between the transfer point (not illustrated) of the sheets 3 to a further-processing machine and the braking device 17 or the transfer length thus remains the same for different formats or cut lengths of the sheets 3, which leads to a considerable simplification in the setting of the apparatus 1 shown in FIG. 2 to a different sheet format. For a format change, the shingling device 10 can be adjusted in its entirety in or counter to the transport direction X of the sheet stream 2, i.e. the raising unit 11 and the deceleration unit 12 are moved together and, for this purpose, can be accommodated or mounted in an undercarriage or frame or carrier movable in and/or counter to the transport direction X of the sheets 3. In principle, it is, however, also possible for only the beater shaft 15 with the beater 16 to be adjusted in or counter to the transport direction X if the suction belt 13 extends sufficiently in the transport direction X.

(16) In the apparatus 1 illustrated in FIG. 2, a suction profile 22 is provided between the shingling device 10 and the braking device 17 below the fast-running transport belt 9, said suction profile being designed as a hollow profile and being connected to a suction intake device (not illustrated), for example a suction blower. Preferably, in the case of a belt section having a plurality of transport belts 9 designed as suction belts, each transport belt 9 is assigned a suction profile 22.

(17) Above a length portion of the suction profile 22 and the assigned portion of the transport belt 9, a first suction intake section 24 is formed between the shingling device 10 and the braking device 17, and a further suction intake section 25 is formed in the region between the shingling device 10 and the cross-cutting device 5. Via the suction profile 22 and the transport belt 9, a negative pressure acts on the sheets 3 at least in the region of the front edge of the sheets 3. The applied negative pressure prevents the front edge of a sheet 3 from being detached. At the same time, the formation of the suction intake section 24 causes the trailing sheet 3 to be transported onward in a defined position after passing through the shingling device 10. A defined under-shingling configuration of the sheets 3 is therefore possible without the sheets 3 obstructing one another. The suction profile 22 preferably extends over the entire length of the region between the cross-cutting device 5 and the braking device 17. In the region upstream of the shingling device 10, the further suction intake section 25 is formed by the suction profile 22.

(18) The negative pressure present at the suction profile 22 is intended to be to be significantly less strong here in the region of the suction intake section 24 positioned downstream of the of the shingling device 10 in the transport direction X than the negative pressure present in the region of the further suction intake section 25 between the cross-cutting device 5 and the shingling device 10. In the region of the shingling device 10, more precisely in the region of the beater shaft 15 with the beater 16, a portion 23 is provided at which no negative pressure or a comparatively less strong negative pressure is present. The sheet 3 can thereby be raised in a simple manner in the region 23 and pressed against the suction belt 13. In the region of the sheet rear edge, the raising unit 11 therefore does not have to counteract a negative pressure which would hold the sheet 3 by its rear edge on the fast-running transport belt 9. A positionally precise transport of the trailing sheet 3 under the upturned leading sheet 3 is therefore possible while at the same time the sheet rear edge can be pressed by the beater 16 against the suction belt 13 without being impaired.

(19) The suction profile 22 can preferably be formed by a continuous hollow profile. The different magnitudes of the vacuum in the region of the suction intake section 24 and the suction intake section 25 can be achieved by a lock or seal in the region of the shingling device 10. In this case, it is possible to provide just one device which generates negative pressure and is connected to the suction profile 22 in the region of the suction intake section 25. A low negative pressure is simultaneously generated in the suction intake section 24 via the lock. The reduction in pressure in the region of the suction intake section 24 in relation to the ambient pressure is preferably significantly smaller than the reduction in pressure in the region of the suction intake section 25.

(20) It is advantageous if the lock in the profile that forms the suction intake sections 24, 25 is designed to be movable, in particular displaceable, in and/or counter to the transport direction X of the sheets 3. The length of the suction intake section 24 can therefore be adapted in a simple manner to the sheet format by adjustment of the lock. At the same time, the length of the suction intake section 25 is also changed, and therefore the sheets 3 are transported in a defined position and appropriately in terms of position from the cross-cutting device 5 to the shingling device 10.

(21) It is particularly advantageous if the movable lock is designed to be adjustable together with the raising unit 11 and/or the entire shingling device 10 in and/or counter to the transport direction X of the sheets 3. For this purpose, a carriage, a framework or a frame (not illustrated) can be provided in which the shingling device 10 and the movable lock are arranged, wherein the carriage can be moved in and/or counter to the transport direction X of the sheets 3. The apparatus 1 can therefore be set in a simple manner to a new or changed sheet format.

(22) If the suction belt 13 of the shingling device 10 extends over a sufficiently long section in the transport direction X of the sheets, it can also be provided that only the raising unit 11 and the movable lock are adjusted together in and/or counter to the transport direction X of the sheets 3.

(23) FIG. 3 schematically shows another apparatus 1 for forming a shingled stream 2 of underlapping sheets 3 in a side view. Identical or corresponding functional units, assemblies, components and other corresponding features of the apparatus 1 shown in FIGS. 1, 2 and 3 are provided with the same reference signs. The formation of a shingled stream 2 of underlapping sheets 3 of paper, foil or cardboard takes place, in the case of the embodiment shown in FIG. 3, in a manner corresponding to the above-described formation of the shingled stream in the apparatus 1 from FIG. 1.

(24) In a departure from the apparatus 1 from FIG. 2, the braking device 17 is designed to be displaceable or adjustable in and/or counter to the transport direction X of the sheets 3 in accordance with the double arrow 21 in order to be able to adapt the apparatus 1 to a changed sheet format. The shingling device 10 in the apparatus 1 shown in FIG. 3 is fixed in position and is therefore not adjustable in and/or counter to the transport direction X of the sheets 3.

(25) The suction intake section 24 is formed according to FIG. 3 by at least one telescopic suction profile which consists of suction profile portions 26 and 27 which can be pushed into one another, and is connected to a suction intake device. The suction profile portion 27 is preferably arranged in a fixed position and the suction profile portion 26 is preferably designed to be displaceable in and/or counter to the transport direction X of the sheets 3. The length of the suction intake section 24 can thus likewise be adapted to the sheet format.

(26) FIG. 4 shows schematically a further apparatus 1 for forming a shingled stream 2 of underlapping sheets 3 in a side view. Identical or corresponding functional units, assemblies, components and other corresponding features of the apparatus 1 shown in FIGS. 1, 2, 3 and 4 are provided with the same reference signs. The formation of a shingled stream 2 of underlapping sheets 3 of paper, foil or cardboard takes place, in the case of the embodiment shown in FIG. 2, in a manner corresponding to the above-described formation of a shingled stream in the apparatus 1 from FIG. 1.

(27) The embodiment of the apparatus 1 shown in FIG. 4 differs from the embodiment of the apparatus 1 shown in FIG. 3 to the effect that the suction intake section 24 is formed from at least 2 intermeshing suction profiles 28 and 29 which can overlap at least in sections transversely with respect to the transport direction X of the sheets 3. The suction profiles 28, 29 are connected in turn to at least one suction intake device. The meshing suction profiles 28, 29 can be formed in an alternating manner transversely with respect to the transport direction X of the sheets 3.

(28) If the rear edge of the suction profile 29 is located at the height of the front edge of the suction profile 28, the maximum length of the suction intake section 24 is reached. If the suction profiles 28, 29 are pushed into one another in a meshing manner, for example the suction profile 28 counter to the transport direction X of the sheets, the length of the suction intake section 24 is reduced.

LIST OF REFERENCE SIGNS

(29) 1 Apparatus 2 Sheet stream 3 Sheet 4 Belt 5 Cross-cutting device 6 Shaft 7 Cutting edge 8 Cutting edge 9 Transport belt 10 Shingling device 11 Raising unit 12 Deceleration unit 13 Suction belt 14 Suction box 15 Beater shaft 16 Beater 17 Braking device 18 Nip roll 19 Transport belt 20 Suction box 21 Double arrow 22 Suction profile 23 Portion 24 Suction intake section 25 Suction intake section 26 Suction profile portion 27 Suction profile portion 28 Suction profile 29 Suction profile X Transport direction Y Transport plane