EP0591099B1 - Method and device for making tied stacks of paper products - Google Patents

Abstract

By means of the device according to the invention, which has a feed means (1), a stack shaft (2) and a tying device (3), a continuous stream of products (U) consisting of paper, especially of those products which are difficult to stack, such as, for example, letter envelopes with content and viewing windows, is processed to form tied stacks. For this purpose, auxiliary stacks (AS) are erected on an auxiliary supporting surface (25) and fall in a controlled way into the stack shaft (2) as individual products. One or more auxiliary stacks (AS) form a stack (S) which is pushed out of the stack shaft (2) and is looped around at least once in the tying device (3) to form a tied stack (G). <IMAGE>

Description

The invention is in the field of further processing of paper products and relates to a method and a device according to the corresponding independent patent claims, with which stacks are made of paper products, in particular of envelopes with or without content.

Paper products, such as newspapers, booklets, etc., are usually produced as a continuous stream from manufacture or further processing and are then often collected and bound in stacks for storage or shipping. For this purpose, the products fall into a stacking shaft which advantageously has a turntable for folded products. When the stack has reached a predetermined height, it is conveyed out of the stacking shaft and guided by means of a conveyor belt to a binding device, where it is pressed together and strapped at least once.

Known methods of this type require that the free fall of the products into the stacking shaft is controlled in such a way that they approach one another exactly come to lie. Furthermore, these known methods require that the stacks are so stable that they can be transported without being disintegrated.

It can now be seen that the fall characteristics of the products depend on the ratio of their weight to their areal extent and on their rigidity, and that the stability of stacks depends above all on whether the products are folded and how strongly the fold is pressed. The easiest way to stack book-like products, for example, is that they have a regular thickness and are relatively stiff and heavy. Newspapers have to be stacked in cross stacks because of the fold.

It also shows that envelopes are not easy to stack. This stems from the fact that empty envelopes or envelopes with little content are light and stiff. Stacking difficulties can also arise from the moveable flaps of open envelopes and the edges of viewing windows where adjacent envelopes can line up.

According to the prior art, these problems are countered by not dropping the products freely into a stacking shaft, but rather pushing them onto the stack, which is possible if the height difference between the top of the stack and the feeder is very small. So that this height difference can be kept small during the entire stacking process, the stacking surface on which the products are stacked is usually moved downwards during the stacking process, correlated with the increase in the stacking height. Stacking devices which operate according to this method are known, for example, from the publications EP-A-0133945 and US-A-4977827.

It is the object of the invention to demonstrate a method with which stacks of paper products, in particular of such difficult to stack products, such as envelopes with content and viewing windows, can be created in the simplest possible way. It is also the object of the invention to provide a device for carrying out the method, which device, in comparison to known devices for stacking paper products, is intended to be simpler, less complex and space-saving despite its applicability for products which are difficult to stack. The device should be able to be easily converted to different formats of envelopes.

It should be applicable for an output of up to approx. 20,000 products per hour.

This object is achieved by the method and the device according to the corresponding, independent patent claims.

Figur 1

eine beispielhafte Ausführungsform der erfindungsgemässen Vorrichtung;

Figuren 2a bis 2h

verschiedene Stadien im erfindungsgemässen Verfahren.

The method according to the invention and an exemplary embodiment of the device according to the invention are to be described with the aid of the following figures. Show:

Figure 1

an exemplary embodiment of the device according to the invention;

Figures 2a to 2h

different stages in the process according to the invention.

FIG. 1 shows an exemplary embodiment of the device according to the invention. This essentially has a feed means 1, a stacking shaft 2 and a binding device 3. With the aid of the feed means 1, envelopes U are in a continuous stream from an envelope manufacturing or processing (filling, addressing, sorting etc.) device with a feed direction Z dem Stacking shaft 2 fed. The envelopes are collected in a stack S in the stacking shaft 2. When the stack has reached a predetermined size, it is ejected from the stacking chute 2 with an ejection direction A, which is directed transversely to the feed direction Z, into the binding device 3, in which the stack S is tied together to form a bound stack G.

The feeding means 1 is designed such that it feeds the envelopes U to be fed in a precisely defined position, advantageously held at least on the trailing edge. This is advantageously, as shown in the figure, a double conveyor belt, the envelopes to be fed being clamped between the two belts 11.1 and 11.2. However, it can also be, for example, a conveyor belt with clamps or a similar means of transport. The feed means opens into the stacking shaft 2 at the top, advantageously on the broad side thereof.

The stacking shaft 2 has a support surface 21 and a front and a rear guide means 22 and 23, which are arranged transversely to the feed direction Z. Furthermore, on a third side, the stacking shaft has an ejection means 24 arranged parallel to the feed direction Z. The ejection means 24 is arranged to be displaceable in the ejection direction A (transverse to the feed direction Z) such that it can be moved between the front and the rear guide means (22 and 23) in the ejection direction A for ejecting a stack S. On the fourth side (ejection side), the stacking chute 2 is open for ejecting the finished stack (as shown) or is designed with guide means which can be removed accordingly for ejection.

The front and rear guide means 22 and 23 of the stacking shaft extend as far as possible in one piece to the binding device 3 and in this extension take over the lateral guidance of the stack S during the ejection. The support surface 21 of the stacking shaft 2 also extends (advantageously in one piece) into the region of the binding device. It does not act as a means of transport, but as a sliding surface over which the stack S is pushed when it is ejected. The bearing surface 21 therefore advantageously has an absolutely flat and as fine a surface as possible; for example, it exists Made of high-gloss polished stainless steel or another slippery material.

A little below the mouth of the feed means 1 in the stacking shaft 2, an auxiliary support surface 25 is arranged therein, for example in the form of a support fork, as shown in the figure. The auxiliary support surface 25 is arranged such that it can be moved in a substantially horizontal direction, advantageously in the feed direction Z, in the stacking shaft 2 and can be removed again in the opposite direction. The function of the auxiliary support surface is to be described in detail in connection with FIGS. 2a to 2h. A front and a rear stop 22.1 and 23.1 are attached above the auxiliary support surface in the feed direction Z and have the same orientation as the front and the rear guide means 22 and 23. The front and the rear stops 22.1 and 23.1 can, for example, be shown on the front in this case and the rear guide means 22 and 23 are integrally formed. The ejection means 24 is designed in terms of height such that it can be moved through under the auxiliary support surface 25.

The binding device 3 corresponds essentially to a known binding device. It advantageously has only one binding point 31 with a press beam, plus a front stop 32 and a conveying means 33. The conveying means 33 is, for example, a conveyor belt which, on the side of the binding point 31 facing away from the stacking shaft 2, represents a support surface and means of transport for the bound stacks. If necessary, the conveying means can also be supplemented on the side of the binding point 31 facing the stacking shaft 2 by corresponding further auxiliary belts or rollers which adjoin the support surface 21 or are arranged laterally therefrom. It must simply be ensured that one of the ejection means 24 is in the binding position pushed stack can be moved by the conveyor 33 after binding.

The ejection means 24 can, for example, as shown, have the shape of an ejection fork, which is arranged displaceably in corresponding slots in the support surface 21. The ejection fork occupies two extreme positions: a stacking position 24.1 and an ejection position 24.2. For ejection, the ejection means 24 moves from the stacking position 24.1 into the ejection position 24.2. The ejection fork is advantageously moved back to the stacking position 24.1 in the same way. However, it can also be moved back into the stacking position 24.1 in another way, for example under the stacking shaft or past the stacking shaft.

In its stacking position 24.1, the ejection means 24 is advantageously slightly spaced from the stack S, so that products that are shifted slightly laterally do not come into conflict with it. However, it can also be used as a lateral guide means of the stacking shaft, in particular together with a second lateral guide means on the ejection side of the stacking shaft. The two lateral guide means are then at a distance from one another which corresponds exactly to the width of the envelopes to be stacked, and they are arranged symmetrically to the feed means 1.

The front stop 32 of the binding device 3 serves for the vertical alignment of the envelopes of a stack in the binding position. This stop is designed in such a way that it can be moved away laterally, for example, to convey the bound stack G away.

As already mentioned, the simplest variant of the device according to the invention has only one binding point 31. If the stacks are to be bound in the middle (only one binding position of the stack relative to the binding point 31), the control of the removal means 33 can be directly coupled to the control of the ejection means 24 will. If the stacks are to be provided with two wraps running parallel to one another (two binding positions of the stack relative to the binding point 31), the conveying means 33 must be controlled in such a way that it promotes a bound stack before it is effectively transported away into a second binding position. Of course, binding devices with two parallel binding sites or binding devices for producing crossed wraps can also be used.

In order to adapt the device to envelopes of different formats, which can differ from one another both in length and in width, the center lines of the feed (arrow Z) and the ejection (arrow A) are centered on a plan of the device cross the stacking shaft at a right angle, keep.

The positions of the front and rear guide means 22 and 23 and of the front and rear stops 22.1 and 23.1 are set to adapt to the expansion of the envelopes in the feed direction Z, the opening point of the feed means 1 in the stacking shaft 2 also advantageously being adjusted. This is realized, for example, in the case of guide means which are molded or fastened to one another and have a corresponding stop, in that the two deflection rollers 12.1 and 12.2 of the double conveyor belt are coupled to the rear guide means 23 or stop 23.1 and are displaced therewith. In order to adjust the length of the conveyor belts, they can be guided, for example, on their return runs via corresponding rollers which can be displaced in a substantially vertical direction (not shown).

To adapt to the expansion of the envelopes transversely to the feed direction Z, the two positions 24.1 and 24.2 of the ejection means 24 and the position of the front stop 32 are set accordingly. The three positions to be set are advantageously coupled to one another in such a way that a single setting action is sufficient for this. For readjustment for smaller envelopes, positions 24.1 and 24.2 are shifted the same distance to the left (in the figure) and stop 32 by the same distance to the right (in the figure). In this case, the movement of the conveyor 33 is not dependent on the format of the envelopes. With such an adjustable device, all stacks are either wrapped in the middle (only one binding position) or are given two wraps with a constant distance from one another (two binding positions). If the distance between the two parallel wraps should be different depending on the envelope format, positions 24.1 and 24.2 and stop 32 must be adjustable independently of one another. Likewise, the control of the removal means 33 must be adjustable, which of course makes the device considerably more complex.

In a further embodiment of the device according to the invention, the feed means 1 can be part of the device delivering the envelopes. Such a feed means must also be designed such that it holds the envelopes in a precisely defined position at least at their trailing edge at least in the region of the mouth into the stacking shaft.

In the feeder, the envelopes can be conveyed one after the other with or without spacing from one another or overlapping one another (scale flow).

Another embodiment of the device according to the invention has two binding devices, one being arranged on each side of the stacking shaft and processing every other stack. Such an embodiment has more capacity. In particular, the ejection means does not have to be moved back from the ejection position to the stacking position, because the ejection position of the ejection means for a stack for one binding device is at the same time the stacking position of the same ejection means for a next stack for the other binding device.

Another embodiment of the device according to the invention differs from that shown in FIG. 1 in that the feed is essentially the same as the ejection. In this case, the envelopes are advantageously guided with a shorter edge against the narrow side of the stacking shaft. In this case, the ejection means can be moved in the same direction as the auxiliary support surface.

The special advantages of the device according to the invention are that it is very compact. The feed means 1 needs a minimal or actually no length and the binding device 3 is arranged directly next to the stacking shaft 2. The auxiliary support surface 25 can be guided into the stacking shaft 2 from one side. The guide means 22 and 23 of the stacking shaft are also guide means for the ejection. For a double wrapping of the stack, only one binding point 31 has to be provided.

FIGS. 2a to 2h now show the method according to the invention in various stages. The device corresponds to the embodiment which was described in connection with FIG. 1, but is no longer shown completely for a better overview.

FIG. 2a shows the feeding of the envelopes U by the feeding means (1, FIG. 1), not shown, in the feeding direction Z. The auxiliary support surface 25 is positioned above the stacking shaft 2. Since the level of the auxiliary support surface is only slightly below the mouth of the feed means, the envelopes do not fall onto the auxiliary support surface 25 or onto other envelopes lying thereon, but are stacked on top of it by the feed means. An auxiliary stack HS is formed on the auxiliary support surface 25. When stacked, the envelopes are aligned in the feed direction Z by the front stop (not shown, 22.1, FIG. 1) and have a fairly exact position transversely to the feed direction thanks to the leading of the trailing edge by the feed means. A complete auxiliary stack HS comprises a predetermined number n (for example 10) envelopes and thus represents a "product" with better fall characteristics than a single envelope, since it is heavier than a single envelope with the same area.

FIG. 2b shows the case of the auxiliary stack HS in the stacking shaft, which is triggered by removing the auxiliary stacking surface 25 when a predetermined number n (for example 10) of envelopes are stacked on the auxiliary supporting surface 25. The auxiliary support surface is advantageously removed from the stacking shaft counter to the feed direction Z (as shown). The auxiliary stack HS is held in position by the rear stop (not shown, 23.1, FIG. 1). The auxiliary support surface could also be moved out of the stacking shaft in the feed direction Z, the auxiliary stack being held in position by the front stop. The movement of the auxiliary support surface from the stacking shaft should be completed as soon as possible as soon as the last envelope of the auxiliary stack has been piled up.

Figure 2c shows the return movement of the auxiliary support surface 25 after the fall of the auxiliary stack HS in the stacking shaft 2. This return movement must be completed, at the latest when the trailing edge of the first envelope of the next auxiliary stack leaves the feed means. This return movement in the feed direction Z advantageously takes place at at least the same speed as the feeding of the envelopes.

FIG. 2d shows a predetermined number m (for example 6) auxiliary stacks HS in the stacking shaft, which form a whole stack S. This can now be pushed out.

Figure 2e shows the ejection process. In this case, by moving the ejection means 24 in the ejection direction A into the ejection position 24.2, the stack S is pushed into a binding position in which the envelopes of the stack are aligned in the ejection direction A by the front stop 32. The ejection means 24 must be moved back into its stack position 24.1 (FIG. 2d) before the first auxiliary stack HS for the next stack is finished.

FIG. 2f shows the stacking chute ready for receiving a next stack, while the stack S that has just been ejected is pressed and wrapped in the binding device (first binding position). As soon as the wrapping is finished, the front stop 32 is removed from the path of the bound stack (as shown) and the conveying means (33, FIG. 1) is activated in such a way that it conveys the bound stack into a second binding position.

FIG. 2g shows the stack S which has already been bound once in the second binding position. The second loop must be completed before the next stack in stacking shaft 2 is finished and has to be ejected.

FIG. 2h shows the ejection of the next stack from the stacking shaft 2 and the simultaneous removal of the bound stack G from the binding device, for example.

With an output of 18,000 envelopes per hour, an envelope is layered on an auxiliary stack HS every 0.2 seconds. Approximately the same amount of time is available to move the auxiliary support surface away from the stacking shaft and also to reposition it. The formation of an auxiliary stack HS of, for example, 10 envelopes U takes 2 seconds. The same time is available to eject a stack and to position the ejection means in the stack position again. The formation of a stack S of, for example, 12 auxiliary stacks (120 envelopes) takes 24 seconds. This period of time is available to bind the stack (in the case of two wraps, therefore approx. 12 seconds per wrapping) and to convey it out of the binding device. From this example of an implementation of the method according to the invention it can be seen that the necessary movements of device parts (ejection means, conveying means, binding device) can be realized with known drives and transmission means.

If the device according to the invention processes a regular, continuous flow of envelopes, such as is supplied, for example, from a device that produces envelopes, it can be controlled purely on a cycle basis, that is to say the control of the auxiliary support surface, the ejection means, the binder and the means of conveyance are carried out by a common cycle correlated with each other. Processes the device An irregular flow of envelopes, such as might arise from a sorting machine, must be fitted with sensor means, for example to determine the height of the auxiliary stack or to count the envelopes fed, the measuring pulses of which are used to control the movement of the auxiliary stack surface. All other movements must be correlated with this control or realized with the help of additional sensory means.

Of course, the device according to the invention can also be controlled in such a way that each stack has an individual size that is dependent on other parameters. The size of the auxiliary stack is advantageously kept constant, so that the smallest stack consists of only one auxiliary stack.

Claims (19)

1. Method for producing bound stacks of paper products (U), particularly those products which are difficult to stack such as envelopes with a content and viewing windows, the method having the following method stages:

   a. continuous supply in a supply direction (Z) of the products (U) in a continuous stream to a supply position at the upper edge of a stacking shaft (2), at least the trailing edge of each product being held in a clearly defined position,

   b. formation of an auxiliary stack (HS) by stacking a predetermined number n of products on an auxiliary bearing surface (25) positioned below the supply position in the stacking shaft, the products being positioned at the front and rear by a front and a rear stop (22.1, 23.1) at least in the supply direction (Z) and the position of the auxiliary bearing surface (25) in the stacking shaft remains unchanged,

   c. formation of a stack (S) by removing the auxiliary bearing surface (25) and allowing the auxiliary stack (HS) to drop onto a bearing surface (21) located below the auxiliary bearing surface in the stacking shaft (2), the auxiliary stack (HS) being guided by guidance means (22, 23) at least on the sides at right angles to the supply direction (Z) and in which the position of the bearing surface remains unchanged,

   d. repositioning the auxiliary bearing surface (25) and formation of a further auxiliary stack,

   e. repetition of stages b. to d. until a predetermined number m of auxiliary stacks has been collected in the stacking shaft (2),

   f. ejection of the stack (S) in an ejection direction (A) into a binding position during the formation of the next auxiliary stack (HS), the stack (S) being moved by an ejecting means (24) over the bearing surface (21) and laterally guided by the guidance means (22, 23), and repositioning of the ejecting means (24),

   g. looping the stack in the binding position for producing a bound stack (G) during the formation of the next stack in the stacking shaft (2),

   h. conveying away of the stack from the binding position prior to the ejection of the next stack.
2. Method according to claim 1, characterized in that the products (U) are supplied with their longer edge at right angles to the supply direction (Z) and the supply direction (Z) is directed at right angles to the ejection direction (A).
3. Method according to one of the claims 1 or 2, characterized in that, after looping in a first binding position, the stack is conveyed into a second binding position and looped a second time.
4. Method according to one of the claims 1 or 2, characterized in that the stack is looped crosswise or parallel.
5. Method according to one of the claims 1 to 4, characterized in that the products are supplied jammed between two conveyor belts (11.1 and 11.2).
6. Method according to one of the claims 1 to 5, characterized in that the auxiliary bearing surface (25) is removed from the stacking shaft counter to the supply direction (Z) and is repositioned in said supply direction (Z).
7. Method according to claim 6, characterized in that the auxiliary bearing surface (25) is moved at at least the same speed into the stacking shaft with which the products are moved by the supply means (1) into said stacking shaft (2).
8. Method according to one of the claims 1 to 7, characterized in that during ejection, the ejecting means (24) are moved over an ejection path from a stacking position (24.1) into an ejection position (24.2) and is moved back over the ejection path for repositioning in its stacking position (24.1).
9. Method according to one of the claims 1 to 7, characterized in that during ejection the ejecting means (24) is moved over an ejection path from a stacking position (24.1) into an ejection position (24.2) and that it is moved back into the stacking position (24.1) over a path differing from the ejection path.
10. Method according to one of the claims 1 to 9, characterized in that the products (U) of a stack (S) in the binding position are oriented in the ejection direction (A) by a front stop (32).
11. Method according to one of the claims 1 to 10, characterized in that n is approximately 10 and m is at least 1.
12. Method according to one of the claims 1 to 11, characterized in that the stacks are ejected alternately in two mutually opposite ejection directions and that the ejection position (24.2) of the ejecting means (24) relative to one binding device is the stacking position (24.1) of the ejecting means relative to the other binding device.
13. Method according to claim 1, characterized in that the products (U) are supplied with their shorter edge at right angles to the supply direction (Z) and that the ejection direction (A) is substantially the same as the supply direction (Z).
14. Apparatus for producing stacks of paper products having a supply means (1) for supplying a continuous stream of products (U) in a supply direction (Z), a stacking shaft (2) for forming a stack (S) and a binding device (3), in which

    a. the binding device (3) is located in an ejection direction (A) from the stacking shaft (2) and the ejection direction (A) is substantially at right angles to the supply direction (Z),

    b. the supply means (1) has holding means with which at least the trailing edge of the products (U) is held in a clearly defined position,

    c. at the upper wide side of the stacking shaft (2) the supply means (1) issues into the latter,

    d. the stacking shaft (2) has a bearing surface (21) extending against the binding device (2) and invariably positioned relative to the height of the stacking shaft and has front and rear guidance means (22, 23) arranged at right angles to the supply direction (Z) and extending counter to the binding device (3),

    e. an ejecting member positioned parallel to the supply direction (Z) for ejecting the stack (S) from the stacking shaft (2) displaceably arranged in the ejection direction (A) in such a way that it is movable from a stacking position (24.1) into an ejection position (24.2),

    f. additionally in its upper area below the issuing point of the supply means (1), the stacking shaft (2) has an auxiliary bearing surface (25), which is so displaceably driven that it is movable substantially in the supply direction (Z) into the stacking shaft (2) and is removable from the latter counter to the supply direction, its position in the stacking shaft being invariable relative to its height,

    g. above the auxiliary bearing surface (25) a front and a rear stop (22.1, 23.1) is oriented on the front and rear guidance means (22, 23),

    h. the ejecting means (24) has a height such that it can be moved under the auxiliary bearing surface (25),

    i. the binding device (3) has a binding point (31), as well as conveying away means (33) connected to the bearing surface (21) in the vicinity of the binding point and a front stop (32) orienting the products of a stack in the binding position, which is displaceable in such a way that it can be moved into and removed out of the conveying away path of the stack.
15. Apparatus according to claim 14, characterized in that the front stop (22.1) is shaped onto the front guidance means (22) and the rear stop (23.1) onto the rear guidance means (23).
16. Apparatus according to claim 14 or 15, characterized in that the front and rear guidance means (22, 23) for adapting the apparatus to envelopes having a different extension in the supply direction (Z) are displaceably arranged parallel to said supply direction.
17. Apparatus according to claim 16, characterized in that the supply means (1) is coupled to the rear stop (22.1) in such a way that its issuing point into the stacking shaft is displaceable with the stop.
18. Apparatus according to one of the claims 14 to 17, characterized in that the two positions (24.1, 24.2) of the ejecting means (24) and the position of the front stop (32) for adapting the apparatus to envelopes with different extensions at right angles to the supply direction (Z) can be displaced.
19. Apparatus according to one of the claims 14 to 17, characterized in that the supply means (1) form part of a device for producing or further processing the products connected upstream of the apparatus.

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