EP0144861A2 - Machine for the zig-zag folding and stacking of webs - Google Patents

Abstract

The material web (23) to be folded is passed through a passage opening (10) which is fixed by two rollers (6, 7). The latter are freely rotatably mounted in a carriage (2) which is driven to move back and forth below the stack (21). Belts (13, 14) are guided over these deflecting rollers (6, 7) and are attached to a fixed frame (1) at both ends (15, 16; 17, 18). These belts (13, 14) are further S-shaped over two further deflection rollers (8, 11; 9, 12), one of which (8, 9) is also rotatable on the carriage (2) and the other (11, 12) is rotatably mounted in the frame (1). A return brake (32) is arranged below the passage opening (10). During the back and forth movement of the carriage (2), the material web (23) is folded in a zigzag manner, the individual material web sections (22) being simultaneously applied to the stack (21) from below.

Description

The present invention relates to a device for forming a stack consisting of superimposed sections of a material web that is zigzag folded along transverse folds, predetermined by weakening lines, according to the preamble of claim 1.

A device of this type is known from AT-PS 181 590, which is used for folding textile webs, ie heavy and stretchable material webs. In this known device, pull rollers are arranged in a carriage arranged below the stack, over which the material web runs and which are driven in opposite directions in a rotating manner. The material web is drawn by these driven pull rollers and conveyed against the underside of the stack. The deflection rollers thus serve as conveyor rollers and keep the web under tension. Because of their opposite direction of rotation, the pull rollers must be pivotally mounted on the carriage so that only one pull roller comes into contact with the underside of the stack. Since one of the two pull rollers must therefore always take up a position lifted from the stack, the stack is not adequately supported in the area of the pull rollers. At the reversal points of the carriage, the material web separates from one pull roller and comes to rest on the other side on the other pull roller. Since the latter is continuously driven in rotation, the material web is accelerated again at the moment in which it comes into contact with the rotating drawing roller, which results in a jerky tensile load. This has no adverse effects with stretchable textile material webs, but can lead to damage to the same in the case of non-stretchable and also thin material webs. in the Furthermore, the material web can move back slightly from one pulling roller to the other pulling roller during this change, since the material web is not supported on any pulling roller during this change. This backward movement of the material web now has the consequence that the point at which the folding takes place is not precisely defined. However, this is also not necessary for the intended use of the known device, namely for folding textile webs. However, this known device is not suitable for protecting thin material webs and in particular paper webs, which have to be folded precisely at locations specified by lines of weakness to process the material web in the desired way.

Furthermore, from DE-OS 24 02 027 a device for folding endless webs of material is known, in which stationary, revolving driven conveyor belts are arranged below the reciprocating stack. Between these two conveyor belts there is a passage gap for the material web, below which a feed device formed from two conveyor rollers is arranged. These conveyor rollers push the web up through the passage gap against a board or the underside of the stack. The material web subsequently captured by the conveyor belts is clamped between these conveyor belts and the board or the underside of the stack. In the end positions of the stack, the direction of rotation of the conveyor belts must be reversed, which now has the consequence that undesirable creasing can occur, especially in the case of thin material webs. In addition, it cannot be achieved with this device that the folding at precisely predetermined, e.g. made by lines of weakness.

The present invention has for its object to provide a device of the type mentioned, which with a simple construction enables gentle folding even of thin and only limited tensile material webs precisely at the specified points.

This object is now achieved according to the invention by the features of the characterizing part of claim 1.

In the present invention, only the function of guiding the application elements is assigned to the deflection rollers. There is no rotating drive of these deflection rollers for the purpose of advancing and retightening the material web. This makes it possible to arrange the deflection rollers in the carriage so that they maintain their position during the carriage stroke. This now has the advantage that the material web is not subjected to shock-like tensile stresses in the reversal points of the carriage and that no drive effect is exerted on the material web in terms of a feed. This allows the material web to be folded gently and in the correct position. Due to the abutment elements which abut or detach from the stack during the carriage movement, gentle application of the material web sections to the stack is made possible without the risk of the material web being wrinkled.

Preferred further developments of the device according to the invention form the subject of the dependent claims.

• Fig. 1 eine Ausführungsform einer erfindungsgemässen Vorrichtung in Seitenansicht und teilweise im Schnitt mit dem Schlitten in einer Endlage,
• Fig. 2 die Vorrichtung gemäss Fig. 1 in Stirnansicht und ebenfalls teilweise im Schnitt,
• Fig. 3 + 4 den Bereich des Stapels der Vorrichtung gemäss Figur 1 mit dem Schlitten in verschiedenen Positionen,
• Fig. 5 + 6 den Stapel und die zu faltende Materialbahn in Seiten- und Frontansicht, und
• Fig. 7 - 9 in gegenüber der Fig. 1 vergrössertem Massstab einen Eckbereich des Stapels mit dem Schlitten in verschiedenen Positionen zu Beginn einer neuen Hubbewegung.

An exemplary embodiment of the subject matter of the invention is explained in more detail below with reference to the drawing. It shows purely schematically:

• 1 shows an embodiment of a device according to the invention in side view and partly in section with the slide in an end position,
• 2 shows the device according to FIG. 1 in front view and also partially in section,
• 3 + 4 the area of the stack of the device according to FIG. 1 with the slide in different positions,
• Fig. 5 + 6 the stack and the material web to be folded in side and front view, and
• 7 - 9 on a larger scale than in FIG. 1, a corner region of the stack with the slide in different positions at the start of a new lifting movement.

The device shown in the figures has a frame 1, which is only partially shown in FIG. In this frame, a slide is slidably guided, which can be moved back and forth in the direction of arrows A and B. In Figure 1, the carriage 2 is shown in its left end position, while the right end position is indicated by dashed lines and designated 2 '. The carriage 2 has a frame 3, on the upper side of which two support plates 4 and 5 are fastened, which end at a distance from one another in the central region of the carriage 2 and thus define an intermediate space. In the area of this intermediate space, two deflection rollers 6 and 7 are arranged, which are freely rotatable, but are immovably mounted in the slide frame 3 in their mutual position. In the front and rear area of the carriage 2, seen in the direction of movement A, B of the carriage 2, two further deflection rollers 8 and 9 are freely rotatably mounted in the frame 3. The axes of rotation of the four deflection rollers 6, 7, 8 and 9 mounted in the slide frame 3 run parallel to one another and at right angles to the direction of movement A, B of the slide 2. The opposite deflection rollers 6 and 7 define between them a passage opening 10 which is substantially perpendicular to the direction of movement A, B of the carriage 2. Below the deflection rollers 6, 7, 8 and 9 mounted on the carriage 2, two further deflection rollers 11 and 12 are arranged, the axis of rotation of which runs parallel to the axis of the deflection rollers 6, 7, 8, 9, which, in contrast to the latter, is stationary, ie in the frame 1, are freely rotatable.

A flexible band 13 or 14 is guided in an S-shape over these deflection rollers 6, 8, 11 or 7, 9, 12. Instead of a single belt 13, 14, a plurality of belts arranged next to one another can also be provided, which are guided in the same way as the belt 13 and 14. The straps 13 and 14 are of finite length and are attached to the frame 1 at their ends at the locations designated by 15 and 16 or 17 and 18 (FIG. 1). A first section 13a or 14a of the belts 13, 14 runs from the one fastening point 15 or 17 in the direction of movement A, B of the slide above the support plates 4 and 5 to the first deflection rollers 6 or 7. A second belt section 13b or 14b which maintains its length during the slide movement runs approximately parallel to the first belt section 13a or 14a from the first deflection roller 6 or 7 to the second deflection roller 8 or 9. The adjoining belt section 13c or 14c runs from the deflection roller 8 or 9 to stationary deflection roller 11 or 12. The band section lying between the latter deflection rollers 11 or 12 and the second fastening point 16 or 18 is designated by 13d or 14d. These band sections 13d and 14d also do not change their length during the carriage movement. The belt sections 13c, 13d and 14c, 14d likewise run essentially parallel to the first belt section 13a and 14a.

Above the carriage 2, stops 19 and 20 (FIG. 1) are arranged, which define a footprint for a stack 21. However, these stops 19 and 20 are not absolutely necessary, since the slide movement does not cause any displacement of the stack 21, as will be explained below. This stack 21, whose base area is designated by 21a and its sides by 21b and 21c, is indicated by Superimposed sections 22 of an endless material web 23 are formed, which can be a paper web, for example. This material web 23 is folded in a manner to be described at the fold points designated 24. These fold points 24 are defined by perforations 25 (FIG. 6), which are arranged at regular intervals a and run at right angles to the longitudinal extent of the material web 23. These perforations 25 are made in a manner known per se and not shown in detail before the material web 23 is folded. As FIG. 1 shows, the material web 23 passing through the passage opening 10 between the deflection rollers 6 and 7 hangs freely downward and forms a loop 25. The material web 23 is guided over a guide roller 27 and by means of a transport device known per se in the direction the arrow C deducted from a supply roll, not shown. The transport device has two transport members 29, of which only one is visible in FIG. 1. Each transport member is provided with protruding pins 29a which engage in a transport perforation 30 (FIG. 6) on each side edge of the material web 23. Each transport member 29 is driven by a drive motor 31, which is preferably a stepper motor.

A return brake 32, shown only schematically, is arranged below the deflection rollers 6, 7 and the passage opening 10 for the material web 23. As shown in the figures, this can be done by two braking elements 33 and 34. are formed, which are opposite each other with respect to the material web 23 and each of which rests on one side of the material web 23. This return brake 32 is designed or set in such a way that the movement of the material web 23 in the feed direction C is at most slightly influenced, but that the material web 23 does not run back. The braking elements 33, 34 can be leaf springs, for example, which, as shown in the figures, can be arranged obliquely against the material web 23. However, these braking elements 33 and 34 can also be formed by material strips provided with a pile in the manner of velvet or plush ribbons, which are designed and arranged in such a way that there is essentially no resistance to movement of the material web 23 in the direction of the line, but that a return movement of the material web 23 against the grain is prevented.

The reciprocation of the carriage 2 is generated by a crank mechanism 35. This has a rocker arm 36 (FIG. 1) which is pivotally mounted at one end about its axis 36a and at the other end engages on the ring 3 of the carriage 2. This rocker arm 36 is articulated to a drive lever 37 which is eccentrically attached to a drive wheel 38 at the other end. The latter is driven in rotation by a motor 39. This orbital movement of the drive wheel 38 has a known manner in which the rocking lever 36 swings back and forth and thus a corresponding back and forth movement of the slide 2.

• In der Figur l ist der Schlitten 2 in seiner linken Endstellung dargestellt. In dieser Endstellung wird der Stapel 21 durch die Stützplatte 4 abgestützt. Der unterste Abschnitt 22 der Materialbahn 23, welcher die Stapelgrundfläche 21a bildet, liegt auf dem ersten Bandabschnitt 13a des Bandes 13 auf. Die Durchtrittsöffnung 10 befindet sich ausserhalb der Stapelgrundfläche 21a benachbart zur Stapelseite 21c. Das andere Band 14 steht mit dem Stapel 21 nicht in Berührung. In dieser Endstellung des Schlittens 2 haben die Bandabschnitte 13a und 14c ihre grösste Länge, während die Bandabschnitte 13c und 14a ihre geringste Länge aufweisen. Aus dieser linken Endstellung heraus wird nun der Schlitten 2 in Richtung des Pfeiles A nach rechts verscho_- ben. Während dieser Verschiebung des Schlittens 2 bewegt sich nun die Durchtrittsöffnung 10 entlang der Stapelgrundfläche 21a von der Stapelseite 21c zur Stapelseite 21b. In Figur 3 ist der Schlitten 2 in einer Zwischenstellung dargestellt. Während dieser Bewegung des Schlittens 2 von links nach rechts wird der Bandabschnitt 13a von der Stapelgrundfläche 21a abgelöst. Dabei verkürzt sich dieser Bandabschnitt 13a, während sich der Bandabschnitt 13c entsprechend verlängert. Gleichzeitig wird nun der Bandabschnitt 14a auf den nächsten Materialbahnabschnitt 22'' zur Einwirkung gebracht und legt diesen unter Bildung eines Falzes 24 an der Stelle der Querperforation 25 von unten an den Stapel 21 an, was ein Anheben dieses Stapels 21 zur Folge hat. Die Verlängerung des Bandabschnittes 14a wird durch eine entsprechende Verkürzung des Bandabschnittes 14c ausgeglichen.

The operation of the device described above is as follows:

• In Figure 1, the carriage 2 is shown in its left end position. In this end position the Stack 21 supported by the support plate 4. The lowermost section 22 of the material web 23, which forms the stack base surface 21a, lies on the first belt section 13a of the belt 13. The passage opening 10 is located outside the stack base 21a adjacent to the stack side 21c. The other band 14 is not in contact with the stack 21. In this end position of the carriage 2, the band sections 13a and 14c have their greatest length, while the band sections 13c and 14a have their smallest length. From this left end position, the carriage 2 in the direction of the arrow A is now verscho right _- ben. During this displacement of the carriage 2, the passage opening 10 now moves along the stack base surface 21a from the stack side 21c to the stack side 21b. In Figure 3, the carriage 2 is shown in an intermediate position. During this movement of the carriage 2 from left to right, the belt section 13a is detached from the stack base 21a. This band section 13a shortens, while the band section 13c lengthens accordingly. At the same time, the band section 14a is now applied to the next material web section 22 ″ and, with the formation of a fold 24 at the location of the transverse perforation 25, places it on the stack 21 from below, which results in this stack 21 being raised. The lengthening of the band section 14a is compensated for by a corresponding shortening of the band section 14c.

In the right end position of the carriage 2, which is dashed in Figure 1 and shown in Figure 4, the stack is now supported by the other support plate 5. The passage opening 10 is now again outside the stack base area 21a, this time adjacent to the other stack side 21b. From this right end position, the carriage is now moved to the left in the direction of arrow B, which is in a corresponding manner a creation of the next material web section 22 with the simultaneous formation of a fold 24 along a perforation line 25 results.

Since the belt sections 13a and 14a are detached from the stack base surface 21a as described in the course of the slide movement or are placed against this stack base surface 21a, no force acts on the stack 21 in the displacement direction A, B of the slide 2, with the result that the stack 21 does not move with the carriage 2, but stays in place. The stops 19 and 20 thus do not have the function of preventing the stack 21 from shifting and can therefore also be omitted. By reversing the movement of the carriage 2 in its end positions, which are spaced apart by a dimension that is greater than the distance a between two adjacent perforation lines 25 (FIG. 6) or fold points 24, a zigzag-shaped folding of the material web 23 at the intended locations, i.e. along the perforation lines 25, and a superimposition of the folded material web sections 22 to a stack 21 is achieved. The stack 21 always remains supported during this application of the material web sections 22.

The fold forming process, which takes place each time the carriage 2 is moved from an end position in the opposite direction, will now be explained with reference to FIGS. 7 shows the carriage 2 again in its left end position, in which the passage opening 10 is located to the left of the stack side 21c defined by the fold points 24. The last material web section applied to the stack 21 is designated 22 '. The next material web section 22 ", which is applied to the stack 21 during the subsequent lifting movement of the carriage 2, is guided in its upper region over the deflection roller 6 and the curvature thereof is bent accordingly. In FIG 8, the carriage 2 is shown in a position shortly after leaving the left end position. As can be seen from FIG. 8, the material web section 22 "has now detached from the deflection roller 6 or the region of the belt 13 running over it and is in the process of being carried along by the other deflection roller 7 or the section of the belt 14 running over it 8, the material web section 22 "is not guided over either of the two deflection rollers 6 and 7 for a short period of time. The return brake 32 now prevents the material web 23 from running back during this time period during which the material web section 22 ″ runs freely in the passage opening 10. Since the material web 23 cannot run back, a bulge 40 () forms in the uppermost section of the material web section 22 ″. Figure 8), which is curved according to the previous bend of this material web section 22 "around the guide roller 6. When the carriage 2 continues to move in the direction of arrow A, the material web section 22 ″ now runs onto the deflection roller 7 and lies against it (FIG. 9). The material web section 22 ′ is bent out in its uppermost region, in the opposite direction to the bulge 40. This in turn has the consequence that when the carriage 2 continues to move, the material web section 22 ″ is now placed on the underside of the stack 21, a fold 24 being formed at the location of a perforation line 25. The fact that the return brake 32 prevents the material web 23 from running back and causes the bulge 40 to form, ensures that the described application of the next material web section 22 ″ to the stack 21 and not detachment of the material web section 22 previously applied to the stack 21 'is caused by the stack 21. Under certain conditions and when processing material webs 23 with certain properties, the return brake 32 can possibly be applied to be dispensed with. However, this return brake 32 is important, among other things, when material webs with a low specific weight are to be processed.

The advantages of the device according to the invention can easily be derived from the preceding description. With this device it is possible to form the stack from below. It should also be noted that at the beginning of the stack formation it is necessary to exert a certain pressure on the first stack layers with the aid of suitable means. This external pressure effect can be dispensed with as soon as the stack has reached a certain height and, due to its own weight, is able to exert a sufficiently large pressure on its stand area. The stacking of the material web sections 22 from below enables the formation of high stacks which do not have the tendency to be inclined and thus have sufficient inherent stability. The stack 21 can be dismantled from above while the formation of the stack continues from below.

The change to a format of a different size, i.e. for folding material webs 23 with a different distance a between adjacent perforation lines 25 can be done in a simple manner by changing the stroke length of the crank mechanism 35. The adjustment of the feed speed of the transport members 29, i.e. The drive speed of the motor 31 can be carried out from the crank mechanism 35 via an electrical control, which means that only a change on the crank mechanism 35 is necessary for the change to another format size.

The described device according to the invention is capable of folding the material web 23 and forming the stack 21 at high speed, even with material webs with a low specific weight.

It goes without saying that the described device can be designed in various parts differently than as shown and described. Only a few of the different possible variants are discussed below.

In order to reduce the friction between the support plates 4 and 5 and the band sections 13a and 14a during the movement of the carriage 2, an air cushion can be generated between the support plates 4 and 5 and the band sections 13a and 14a. This can be done, for example, by providing the support plates 4 and 5 with through holes through which air is blown between the top of the support plates 4 and 5 and the band sections 13a and 14a. The deflection rollers 11 and 12 do not necessarily have to be rotatable. If the other deflection rollers 6, 7, 8 and 9 were not rotatably mounted, the belts 13 and 14 would have to slide over these rollers, which would have disadvantages.

The fact that the material web 23 hangs freely underneath the passage opening 10 in the form of a loop 25 ensures that a sufficiently large material web supply is available to enable a perfect folding and stacking even when the material web 23 is fed discontinuously. For the regulation of the _D loop urchhanges 25 can in this one dancer roller of a known sag control be inserted.

Instead of guiding the belts 13 and 14 over the deflection rollers 11 and 12 and attaching them to the frame 1 at points 16 and 18, it is also possible to use these belts 1 ₃ and 14 to attach to the pulleys 11 and 12 and to arrange straps between the latter and the anchoring points 16 and 18. The latter can be kept tensioned by means of a tensioning mechanism, which also results in the belts 13 and 14 being kept tensioned via the rotatable deflection rollers 11, 12. In other words, in this variant, the band sections 13d and 14d are replaced by tensioning bands separated from the bands 13 and 14.

Although the device described is not exclusively suitable, it is particularly suitable for processing paper webs that have previously been used in a printer, such as that e.g. used in data processing systems, have been printed and run through this printer at high speed.

Although the device described is particularly suitable for placing the material web sections on the stack from below, it is also conceivable to feed the material web from above and to fold it in a corresponding manner in a zigzag manner, the material web sections being placed on the stack from above.

Claims (13)

1. Device for forming a stack (21) consisting of superimposed sections (22) of a material web (23) folded along transverse transverse fold lines (25) predetermined by weakening lines (25), with a carriage (2) which is between two end positions is movable back and forth and the one which runs essentially at right angles to its direction of movement (A, B), during carriage movement along an end face (21a) of the fixed stack (21) from one side (21c; 21b) to its other side ( 21b; 21c) movable passage opening (10) for the material web (23) to be folded, further two deflection rollers (6, 7) which define this passage opening (10) between them and run essentially parallel to each other, and arranged on both sides of the passage opening (10), has in the direction of movement (A, B) of the carriage (2) each to a deflection roller (6, 7) extending and guided around this positioning elements (13, 14), so that at each carriage stroke, the contact element (14; front; viewed in the direction of movement (A, B) with respect to the passage opening (10); 13) can be detached from the last material web section (22 ') applied to the stack (21), while the other, rear application element (13; 14) applies the subsequent material web section (22 ") to the stack (21), characterized in that the Deflection rollers (6, 7) are arranged in the carriage (2) while maintaining their position with respect to the carriage (2). 2. Device according to claim 1, characterized in that the deflection rollers (6, 7) freely rotatable in the carriage (2) are stored. 3. Device according to claim 1 or 2, characterized in that the carriage (2) is arranged below the stack (21) and is designed as a support for the latter. 4. Device according to one of claims 1-3, characterized in that each of the two application elements is formed by at least one flexible band (13, 14), the first, with the stack (21) along one of its end faces (21a) in contact bringable section (13a, 14a) extends from a fixed attachment point (15, 17) to the associated deflection roller (6, 7). 5. The device according to claim 4, characterized in that each band (13, 14) from the associated deflection roller (6, 7) to a compensating arrangement (8, 9; 11, 12), which changes the length of the carriage movement compensates for the first section (13a, 14a) of the associated band (13, 14). 6. The device according to claim 5, characterized in that each band (13, 14) behind the associated deflection roller (6, 7) to a second deflection roller (8, 9) which is arranged on the carriage (2) and is preferably freely rotatable, and is guided around it and then runs in the opposite direction to a stationary element (11, 12), so that the section (13c, 14c) lying between the second deflection roller (8, 9) and the stationary element (11, 12) each band (13, 14) changes in length in accordance with the change in length of the first band section (13a, 14a) in the opposite sense. 7. The device according to claim 6, characterized in that a further band section (13d, 14d) runs between each fixed element (11, 12) designed as a preferably freely rotatable deflection roller and a second fastening point (16, 18). 8. Device according to one of claims 1-7, characterized by one of the passage opening (10) upstream return brake (32). 9. The device according to claim 8, characterized by two with respect to the path of movement of the material web (23) opposite and each on one side of the material web (23) to act certain brake elements (33, 34). 10. Device according to one of claims 3-9, characterized in that the carriage (2) on both sides of the passage opening (10) each has a plate-like support member (4, 5) for supporting the stack (21), via which the first section ( 13a, 14a) of the band (13, 14). 11. The device according to claim 10, characterized in that between the first portion (13a, 14a) of each band (13, 14) and the underlying support element (4, 5), a gas cushion, preferably an air cushion, can be generated or is present. 12. Device according to one of claims 1-11, characterized in that the drive for the carriage (2) is designed as a crank mechanism (35). 13. Device according to one of claims 2-12, characterized characterized by a feed mechanism (29) for advancing the material web (23) to form a loop (25) sagging downward from the passage opening (10).

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