EP1266854B1 - Transport device for sheets and method for assembling sheets - Google Patents

Description

The invention relates to a conveyor for sheet layers, which in particular at least one collecting area can be fed, with at least two successively arranged conveying devices, of which the forward conveying device in the conveying direction has a lower speed than the rear, wherein at least one ionizer is included, by means of which the sheet layers electrostatically are rechargeable. The invention further relates to a method for bringing sheet layers together.

In the case of corresponding generic conveyors, a continuous flow of, for example, sheets or sheet layers coming from a cross cutter is fed to a collection area, such conveyors being fed at a comparatively high speed work. At such high speeds, it is difficult to deposit the sheet layers in a collection area without damaging them. The speed of the sheet or sheet layers must be significantly reduced when depositing, otherwise no regular storage of the sheet layers is possible. In the case of large differences in speed, a number of speed reduction stages have hitherto been connected in series. However, this means a considerable construction effort.

From DE-PS 2 100 980 a generic conveyor or conveyor is known in which in particular by means of an ionizing the sheet and at least one of the conveyor belts is electrostatically charged, so as to allow an electrostatic braking of the bow. In this case, it is preferable to arrange ionizers on both sides of the cut sheets in motion, whereby control of the sheets to one of the collecting areas is feasible.

DE-AS 1 245 702 discloses a device for conveying, overlapping and depositing, for example, sheets of paper or the like ejected from cross-cutters with a conveyor belt and a further conveyor belt of lower speed connected downstream of it and arranged lower in the conveying direction. In this case, individual sheets are tightened on a slowly moving belt, the so-called. Abbremsband by suction. A device acc. This document is not suitable for several superimposed sheets, so-called sheet layers or paper clips.

From DE 34 09 548 C2 of the Applicant a method and apparatus for braking and overlapping of paper sheets in paper processing machines is known in which the individual sheets or sheet layers are braked by means of at least one brake roller. However, such a machine or such a method and such a device is less suitable for sensitive papers and for very high speeds, as this can damage the sheet or sheet layers.

Compared to this prior art, it is an object of the present invention to provide a conveyor of the type mentioned, in which the example. From sheets cut or sorted sheet can be transported at very high speed and this high conveying speed on a relatively short distance to a to drop suitable speed is reduced. This should be excluded damage to the sheet or sheet layers.

This object is achieved by a conveyor according to claim 1.

By combining an ionizer and a suction device is not expected for the expert and realized unexpectable advantage, namely that at a low mechanical complexity sheet layers can be slowed down from very high speed to lower speed and overlapped without damaging them. The combination of the ionization of the sheet layers and a concomitant electrostatic cohesion of the sheet from the respective sheet position and the use of a suction device for braking and tightening the sheet layers overall, the success of the invention is ensured.

By the embodiment that the at least one region of the sheet layers is arranged in the conveying direction in the rear region of the sheet layers, in particular in the vicinity of the edge of the respective sheet layer, it is possible long format sections or long sheet layers at a slower speed in the slow conveyor, ie the front conveyor to transport, as this has been possible. Furthermore, this means a non-contact braking of the sheet layers at the trailing edge, whereby no damage to the leading edge takes place even at high paper web speeds or sheet speeds. Here, the long format sections or sheet layers are no longer pushed together in the braking phase, as this happens in the otherwise conventional inertia of sheet layers when braking at the front edge.

A particularly preferred embodiment is given when the front conveyor device comprises suction openings. By providing suction openings in the front conveyor, in particular in corresponding conveyor belts, a particularly simple constructive and inventive design of the front conveyor possible. Preferably, the suction openings pass through at least one conveyor belt of the front conveyor. The at least one conveyor belt can then be called, for example, also suction belt. In the context of the invention, a plurality of juxtaposed conveyor belts or suction belts are preferably used. These are preferably three.

A particularly effective braking or bringing down the speed to the speed of the front conveyor belt or the front conveying direction is given when the suction device comprises at least one suction box with suction slots, which can be brought into operative connection with the suction openings. If the suction openings are arranged at a predeterminable, in particular uniform, distance from one another on the at least one conveyor belt, a format-independent overlapping distance can be selected. The overlap distance is accordingly preferably adaptable and depends on the hole spacing of the corresponding suction holes in the at least one conveyor belt.

A particularly effective ionization or electrical charging of the sheet layers can be realized if the conveying device or at least one further element is at least partially electrically conductive in the region of the ionizing device. For this purpose, an electrically conductive element is preferably provided, which is in particular stationary.

A particularly preferred embodiment of the conveyor device according to the invention is realized when a phase shift as a function of the speed of the conveyor between the at least two is provided behind one another arranged conveying devices. The phase shift serves to compensate for the inertia of the sheet layers to higher speeds of the conveyor. It should be noted that the higher the speed of the sheet layers, the sheet layers to slip over the corresponding suction holes, before a complete fixation is done by the suction air to the corresponding conveyor belt. Preferably, there is a linear relationship between the phase shift and the speed of the conveyor. Further preferably, the greater the speed of the conveyor, the more the phase of the front conveyor of the phase of the rear conveyor.

According to the invention, a paper processing machine is provided with at least one of the aforementioned conveyors. Such a paper processing machine processes in particular paper, but also so-called. Tissue. Such a paper processing machine serves, in particular, to cut, stack and package paper as well as tissue.

The object is further achieved by a method for bringing together sheet layers with the method steps of claim 12.

The inventive method steps, it is possible to bring together without slipping the sheet in the sheet layers, in particular on a slower conveyor belt or Abbremsband and in particular to overlap, with a very fast process control and a very gentle process management is possible. Furthermore, it is possible to set the difference in speeds between the supplied sheet layers and the overlapping sheet layers significantly higher, so that a slower striking the overlapping sheet layers on the front stop a collection box a corresponding paper processing machine is possible, making this attack is also gentle. As a result of the slow impact on the front stop, the sheet layers brought to overlap are thus gently accumulated, preferably subsequently to the abovementioned method steps, to form a sheet stack.

If the application of suction air in relation to the time of transporting the sheet layers in the overlap region with a phase shift occurs, which is a function of the speed of transporting, a very secure process management is possible. If the phase shift is such that the application of suction air is the earlier, the faster the transport of the sheet layers, especially in a first transport device, is possible to generate a very high degree of overlap.

Fig. 1

eine Seitenansicht eines wesentlichen Teils der Fördereinrichtung in schematischer Darstellung,

Fig. 2

eine Detailansicht des Überlappungsbereichs der Fördereinrichtung aus Fig. 1,

Fig. 3

eine Aufsicht auf einen Teil der Fördereinrichtung aus Fig. 1 in schematischer Darstellung,

Fig. 4

eine Detailansicht aus der Fig. 3, und

Fig. 5

ein Diagramm der Phasenverschiebung als Funktion der Maschinengeschwindigkeit.

The invention will be described below without limiting the general inventive idea using exemplary embodiments with reference to the drawings, wherein all details not described in detail in the text according to the invention in the drawings explicitly referenced. Show it:

Fig. 1

a side view of an essential part of the conveyor in a schematic representation,

Fig. 2

a detailed view of the overlapping region of the conveyor of FIG. 1,

Fig. 3

a plan view of a part of the conveyor of FIG. 1 in a schematic representation,

Fig. 4

a detail view of FIG. 3, and

Fig. 5

a diagram of the phase shift as a function of the machine speed.

In the following figures, the same elements are provided with the same reference numerals, so that apart from a renewed idea.

Fig. 1 shows a side view of the essential part of a conveyor according to the invention.

Paper clips 33 are between a top belt 20 and a conveyor belt 23 in the conveying direction 10 in the direction a Abbremsbandes 24 transported. The upper belt 20 is deflected by means of deflection rollers 21 and by means of a drive roller or a drive unit, which is not shown in Fig. 1, driven. Accordingly, the conveyor belt 23 is deflected via deflection rollers 21 and driven by a drive roller 22. The same applies to the Abbremsband 24 and the lower band 25th

The paper clips consisting of some paper sheets, such as 4 to 7 sheets, are electrically charged by means of an ionizer 30 provided with an electrical connection 31 and the electrostatic field 32 produced thereby, so that the paper sheets are held together in the respective paper clip 33 , To reinforce the electrostatic field or to focus a corresponding field, a counter electrode 27 is preferably provided, which is preferably electrically conductive. A corresponding ionizer, which may be, for example, an electrically conductive rod, which may be connected to a van der Graf generator or other commercially available high voltage source, is known, for example from DE-PS 2,100,980.

The correspondingly loaded paper clips 33 are then transported into the overlap area 26 where they are in the rear area, i. in Fig. 1 in the left area, are pulled by suction down and brought into the engagement region of the Abbremsbandes 24. In order to allow suction air 35 to engage the paper clips 33, a suction box 34 is provided in this embodiment, which is shown broken in Fig. 1.

Instead of the suction box shown in Fig. 1, it is also possible to provide a Abbremsband or conveyor belt 24, which is hollow in itself and the cavity with Vacuum can be applied or in which the gas of the cavity can be sucked out. There are also other suction devices conceivable.

In the overlap region 26 so several paper clips 33 come to overlap. These are then overlapped between the upper belt 20 and the lower belt 25 further transported in the transport direction to the right, where this is then posted to a front stop, which is not shown, gently and slowly, so that corresponding sheet stacks are generated. The speed of the Abbremsbandes 24 corresponds approximately to the speed of the lower belt 25th

FIG. 2 shows a detail of FIG. 1 in more detail. In particular, the suction slot 36 of the suction box 34 is shown more clearly in this figure.

In Fig. 3 is a plan view of a portion of the conveyor of FIG. 1 is shown schematically. It is a machine frame 40 and a carrier 41 is shown, wherein above the carrier 41 are each three suction boxes side by side each side by side led stream of paper clips 33 are provided. In particular, the suction slots 36 and the suction holes 37 are shown. In Fig. 3, a lower paper clip 38 is shown by 38 and a line from bottom left to top right and only schematically on the right side of the two Papierclipströme. Further, an upper paper clip 33 is shown, which is lined from top left to bottom right. This ruling has been made for the sake of clarity. It can be seen that the suction holes 37 located at the top in FIG. 3 lie in the region of the suction slots 36, that is to say that suction air acts on the paper clip 33 lying on top. The bottom in Fig. 3rd shown suction holes 37 are outside the range of the suction slots 36, so that no more suction occurs through this. Thus, the lower paper clip 38 is no longer held by suction, but only by the weight itself. The Abbremsbänder 24 and brake belts are indicated in Fig. 3 only. These are extended further upwards and downwards in FIG. 3 as well as in FIG. 4 to introduce, whereby suction holes 37 are provided correspondingly at preferably equidistant intervals.

4, a detail of Fig. 3 is shown in detail. The thin lines drawn in Fig. 4 are under objects that are above them. For example, a lower paper clip 38 and an upper paper clip 33 are shown, wherein the upper paper clip 33 has been interrupted in the lower region of FIG. Furthermore, both the Abbremsbänder 24 and the suction boxes 34 are below the paper clips 33 and 38. The suction box 34 with the suction slots 36 is further below the Abbremsbänder 24 with the suction holes 37 located in these. Also in Fig. 4, the conveying direction 10th the paper clips 33 and 38 shown.

The following exemplary embodiment is to be named for the method of operation for contacting sheet layers or paper clips: First, a paper clip 33 is electrostatically charged by means of the ionizer 30 and optionally the counter electrode 27, so that the paper clips or the sheets are held together in the paper clip. Upon further transporting the loaded paper clips in an overlap area 26, the paper clips 33 are brought to overlap, being transported in the rear region of the just in the overlap area Paper clip 33 suction air is applied. This happens in that at the moment where the rear portion of the clip 33 enters the overlap region, the corresponding suction holes 37 of the Abbremsbänder 24 are brought into the effective range of the suction box 34, ie above the respective suction slots 36.

On the further transport path, the paper clip 33 is held by the suction air as long as the suction holes 37, which are in engagement with the suction slot 36, are still in engagement therewith. Once they are outside the range of the suction slots, no suction air is passed through the suction openings, so that the tightening of the paper clips 33 is terminated by means of the suction air. In the further course of conveying the paper clips they are pushed together in a front stop, which is not shown in the figures, and indeed to stacks of paper.

At faster transport speeds of the pulse of paper clips 33 is correspondingly larger. In order to achieve a sufficient fixation with the suction air, it is useful to provide a phase shift between the Abbremsband 24 and the upper belt 20. The faster the speed, the sooner the suction air should be able to attack the paper clips to compensate for the increasing momentum.

FIG. 5 shows a diagram in which two functions of the phase shift 50 are shown as a function of the machine speed 51. With 52 a linear function is shown and with 53 another function, for example, at low machine speeds an exponential or quadratic Rise is provided and to higher machine speeds a linear course. The size of the suction openings, the size of the paper clips, the size of the vertical distance, for example. Of the upper band 20 and the Abbremsbandes 24, the roughness of the paper and / or the suction power, for example, the suction boxes or the number the suction boxes, different functional characteristics can be advantageous. Thus, for example, with a correspondingly very high suction power or a high degree of adhesion of the paper clips 33 on the braking belt 24, the further curve 53 may be preferred.

LIST OF REFERENCE NUMBERS

10

conveying direction

20

top belt

21

idler pulley

22

capstan

23

conveyor belt

24

Abbremsband

25

low band

26

overlap

27

counter electrode

30

ionizer

31

electrical connection

32

electrostatic field

33

paper clip

34

suction box

35

suction

36

suction slot

37

suction hole

38

lower paper clip

40

machine frame

41

carrier

50

phase shift

51

machine speed

52

linear curve

53

another curve

Claims (15)

1. Conveying apparatus for quires (33) of sheets, said apparatus having at least two conveying devices (23, 24) which are disposed one behind another and of which the conveying device (24) which is at the front in the direction of conveyance has a lower speed than the rear conveying device, wherein at least one ionising apparatus (30, 31), by means of which the quires (33) of sheets can be electrostatically charged, is included, characterised in that there is disposed, in the region of the front conveying device (24), a suction apparatus (34) by means of which the quires (33) of sheets can be impinged upon by suction air (35) in at least one rear region of said quires (33), the sheets from the individual quire of sheets being held together electrostatically by ionisation of the quires (33) of sheets in such a way that said quires (33) of sheets are not telescoped into each other in the braking phase.
2. Conveying apparatus according to claim 1, characterised in that the at least one region of the quires (33) of sheets is disposed, in the direction of conveyance, in the rear region of said quires (33).
3. Conveying apparatus according to claim 1 and/or 2, characterised in that the front conveying device (24) comprises suction apertures (37).
4. Conveying apparatus according to claim 3, characterised in that the suction apertures (37) pass through at least one conveyer belt (24) belonging to the front conveying device (24).
5. Conveying apparatus according to claim 3 and/or 4, characterised in that the suction apparatus (34) comprises at least one suction box (34) which has suction slits (36) and can be brought into operative connection with the suction apertures (37).
6. Conveying apparatus according to claim 4 and/or 5, characterised in that the suction apertures (37) are disposed at a predeterminable, in particular uniform, distance from one another on the at least one conveyer belt (34).
7. Conveying apparatus according to one or more of claims 1 to 6, characterised in that, in the region of the ionising apparatus (30, 31), the conveying device (23) or at least an additional element (27) is partly electrically conductive.
8. Conveying apparatus according to one or more of claims 1 to 7, characterised in that a phase displacement (50) in dependence upon the speed of the conveying apparatus is provided between the at least two conveying devices (23, 24) disposed one behind another.
9. Conveying apparatus according to claim 8, characterised in that a linear correlation exists between the phase displacement (5) and the speed (51) of the conveying apparatus.
10. Conveying apparatus according to claim 8 and/or 9, characterised in that the phase of the front conveying device (24) runs further ahead of the phase of the rear conveying device (23), the greater the speed (51) of the conveying apparatus.
11. Paper-processing machine having at least one conveying apparatus according to one or more of claims 1 to 10.
12. Process for bringing together quires (33) of sheets, said process comprising the following process steps:

    - electrostatic charging of the quires (33) of sheets, so that the sheets of the individual quires (33) are held together electrostatically in such a way that said quires (33) of sheets are not telescoped into each another in the braking phase.

    - transporting of the charged quires (33) of sheets into an overlapping region (26) in which the quires (33) of sheets which are disposed one behind another in the direction of transport are caused to overlap, and

    - impingement of suction air (35) upon the quires (33) of sheets which are to be caused to overlap, at the end of said quires which is at the rear in the direction of conveyance, in order to bring said quires to a speed which approximately corresponds to that at which the quires (33) of sheets which have already been caused to overlap are transported.
13. Process according to claim 12, characterised in that the quires (33) of sheets which have been caused to overlap are subsequently accumulated to form a stack of sheets.
14. Process according to claim 12 and/or 13, characterised in that the impingement of suction air (35) takes place, in relation to the point in time at which the quires (33) of sheets are transported into the overlapping region (26), with a phase displacement (50) which depends upon the speed (51) of transportation.
15. Process according to claim 14, characterised in that the phase displacement (50) is such that the impingement of suction air (35) takes place earlier, the quicker the transportation of the quires (33) of sheets.

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