EP3002240B1 - Brake for printed sheets - Google Patents

Description

Technical area

The present invention relates to a device and a method for braking and positioning a printed sheet in a processing machine with at least one braking force generating means.

This braking and positioning of the printed sheet is available for a basic operation, which is preferably associated with the production of folded printed sheets in a folder, the folder typically being equipped with a transverse and / or longitudinal folder.

The printed sheets are typically processed from a paper roll, which is first printed by a printing machine (digital or offset) and then fed inline into the folder, the braking and positioning of the printing sheet initially creating the conditions for the folding to be qualitative and constant during the entire production can be maintained, even at high cycle rates.

With the secured positioning of the printed sheet before the folding operation, already printed paper rolls can also be used. Loose printed sheets can also be fed to the folding device in isolation, whereby it must also be ensured here that a secure prior positioning takes place in front of the folding device.

State of the art

Folding the various substrates (papers), especially in the longitudinal fold, is particularly challenging from a process engineering point of view, since the printed sheet is deflected by 90 ° from the feed direction by means of a sword and fed to a so-called pair of folding rollers. Before the printed sheet parts are fed to the pair of folding rollers by means of a sword or other folding device, the printed sheet part, typically coming from a cross folder, must be decelerated from the feed speed to 0 in a very short time (a few milliseconds or fractions of milliseconds). With longitudinal folding devices known today, this happens either with a printing sheet stop or with a combination of printing sheet stop and brush.

The purpose of the brush is to slow down and smooth the incoming print sheet parts within the width of the brush. The printed sheet parts mostly come into the longitudinal folding device with the folding edge (cross fold) first. However, unfolded ones (i.e. without a cross fold) can also be fed to the longitudinal folder.

The longitudinal hemming process is basically state of the art. The main problem with the print sheet deflection into the folding rollers is above all the braking of the print sheet at the so-called print sheet stop. When the printed sheets hit the printed sheet stop, the entire deceleration energy is generated suddenly. This leads to the fact that the individual print sheet is compressed in the area of the print sheet stop or, in the case of stiff print sheets, part of the energy is converted in the form of a spring back.

The compression of the printed sheets can, depending on the speed and type of paper, lead to damage to the folded edge and thus to poor products. When the printed sheets spring back, they can also twist slightly in relation to the optimal geometric position: When the sword is then pierced, this leads to oblique or parallel folds. To this negative A wide variety of measures have already been proposed to reduce or eliminate effects, which are part of the state of the art.

For example, the brake brush or brushes are located in the area in front of the sheet stop. These must each be set to the product thickness. The disadvantage of this solution is that the brake brushes are subject to severe mechanical wear and the adjustment of the thickness on the paper is usually complex. The feeding upper belts can also only be guided to the end of the printed sheet part. This prevents kickback or the product is returned to the stop. In this case, however, injuries to the printed sheet at the stop are not prevented. A combination with the above solution is also conceivable. Further known systems are actively controlled braking devices which brake the printed sheet at the end so that it is only aligned with the stop.

the end DE19921169 C2 a device for braking sheets of paper has become known. With this device, the products are advantageously braked and stopped at the rear so that they can be stretched and smoothly placed on the surface, e.g. B. rest on a folding table. The device has a compact and simple structure with few components. This facility is easy to control. The device can be used as a sheet brake on folding tables, as a brake in slowing stations or in front of the compartments of paddle wheels, so that the products can be further processed undamaged according to the description. Paper sheets are conveyed over a support by conveyor belts (not shown in the drawing), for example to a folding table of printing machines. These paper sheets can be products cut from paper webs by cross-cutting devices, which products can be unfolded or folded one or more times. The products can be collected or uncollected. A carrier is fastened to a frame and runs above along the direction of paper travel. At its end facing away from the frame, an electromagnet is arranged on the carrier. An armature preferably moves in its bobbin perpendicular to the direction of movement and surface of the paper sheets. At its end facing the course of the path, the anchor carries a brake shoe to which a brake lining is attached. The brake shoe is by means of a spring element, for. B. a leaf spring made of spring steel or plastic material, resiliently movable, connected by a receptacle on the carrier. However, a helical spring that is received directly by the armature and is supported both on the housing of the electromagnet and on a shoulder of the armature would also be conceivable. By electrically activating the electromagnet, a magnetic flux field is generated, by the force of which the sheet of paper is pressed from the armature via the brake shoe with its brake lining against another brake lining which is fixedly arranged on the support.

the end DE4307383 A1 discloses a device for braking sheets, in particular sheets of paper. The sheets are guided one after the other to a braking device by a high-speed belt section, consisting of several lower belts and upper belts arranged at a distance from one another. While the outlet-side deflection rollers of the lower belts are located in front of the braking device, the upper belts extend further into the area of the braking device. The braking device consists of a guide plate which is arranged below the inlet level and extends over the working width. At the end of the guide plate on the web outlet side, a slot nozzle is arranged, from which compressed air is blown against the sheet travel direction over the top of the guide plate and is directed upwards from its upwardly curved end. The air flow creates a negative pressure that pulls the trailing edge of the sheets down and at the same time brakes the sheets. Immediately after the air nozzle, there is a machine-wide, circumferential overlapping cloth that is moved at the slower depositing speed. The sheets deflected downwards by the air flow from the nozzle detach from the upper belts and lie on the cloth. The leading edge of the following, still unbraked printed sheet slides over its trailing edge, creating an imbricated flow that is transported on at the slower depositing speed.

the end EP 0 955 257 A2 a method or a device emerges in which it is a reproducible feeding of sheet-like material, preferably sheet metal, to bring about alignment stops of a printing or painting machine, the sheet-like material being moved along a feed path that may have slide rails. It is provided that the friction between the sheet-like material (see FIGS. 4 and 5, item 15) and the feed path can be changed at least along a section of the feed path. It can be provided that a rear corner area (see FIGS. 4 and 5, item 26), viewed in the feed direction, is elastically bent out of the plane of the sheet-like material by the application of force. Accordingly, this publication does not reveal a device with at least one first means and at least one second means for generating braking force, in which different measures and different effects are used to transmit the braking force.

Presentation of the invention

The invention is based on the object, in a device and method of the type mentioned at the outset, to decelerate printed sheets at a high speed in a very short time with precise positioning, stable and complete, before these printed sheets are then subjected to further processing as intended.

In most cases, this precise braking is closely related to further processing of the printed sheets, in which precise positioning is a prerequisite for achieving the desired quality.

However, there are also cases in which the precise position braking of the printed sheets is only an intermediate step that does not have to be directly or necessarily in operative connection with subsequent further processing.

Regardless of the final purpose of this precisely positioned braking, the invention is therefore based on the object that, on the one hand, the printed sheets are neither damaged nor injured during this braking, and, on the other hand, that their positioning always remains exact throughout the entire production process.

Starting from a preferably operated further processing, the printed sheets are fed to a folding device after their position-accurate braking, such further processing, as already mentioned, is not to be understood as exclusive and mandatory.

The invention seeks to propose a qualitative and economical development of the prior art, which involves a device and a method with the aim of braking the printed sheet at the exact position:
This braking takes place by pneumatic means, which inject braking force-releasing air impulses, and in which the resulting braking force acts directly and / or indirectly on the printed sheet in the broader sense.

With direct implementation, the air impulses that trigger the braking force are aimed directly at the printed sheet and implement their effect there, with the number, strength and location of these air impulses being adapted to the given conditions.

In the case of indirect implementation, the air impulses that trigger the braking force act on at least one mechanical element which is arranged intermediately between the printed sheet and the source of the air pulse, such that the effective braking effect on the printed sheet then takes place through said element, such an element can have different dynamic configurations.

In addition, the precise braking of the printed sheet in the delivery direction can also be achieved, at least in part, by a negative pressure that can be generated on the printed sheet, which can be achieved by taking suitable precautions within the table-like documents, usually located below the conveyor belts, with an effect on the printed sheet. This increases the friction between the surface of the table-like documents and the underside of the printed sheet in such a way that this frictional force can preferably also be used as a fine adjustment for an exact end positioning of the printed sheet. As already mentioned above in connection with the air pulses, the number, strength and location of action can also be adapted to the given conditions for the implementation of the negative pressure on the printed sheet.

The two braking forces, i.e. the braking force-triggering impulses on the printed sheet, be they operated directly or indirectly, as well as the increase in friction due to negative pressure, can be controlled interdependently or independently of one another, with the braking force component of the two changing or. can be customized.

Of course, an additional braking force can also be achieved by at least one mechanically activatable element, which, for example, can be used for fine adjustment in addition to the pneumatic braking force-triggering pulses acting on the printed sheet, such a mechanical element being easily carried out by an autonomous control or, in the above sense, purely by air pulses can be operated.

The braking force-releasing precautions mentioned on the printed sheet allow continuous optimization of the braking and frictional forces that act, in that a controlled procedure is used in which the precautions mentioned are used interdependently or individually.

Such a procedure, which provides for the integration of the direct and / or indirect braking as well as the braking by triggering additional friction effects on the printed sheet, has a particularly advantageous effect when it comes to feeding the printed sheet before or after the folding process, for example to form flakes or to achieve a corresponding flake unbundling or flake isolation.

1. 1. Die positionsgenaue Abbremsung im Sinne eines punktgenauen Stillstandes des Druckbogens wird allein durch bremskraftauslösende Impulse und/oder durch weitere Bremskrafteinbringungen bewerkstelligt. Bei letzteren Mitteln lässt sich dies beispielsweise durch Bildung eines auf den Druckbogen wirkenden Unterdruckes und/oder durch den Einsatz mindestens eines mechanischen Elementes erzielen.
2. 2. Die positionsgenaue Abbremsung im Sinne eines punktgenauen Stillstandes des Druckbogens lässt sich durch bremskraftauslösende Impulse und/oder durch weitere Bremskrafteinbringungen, wie oben unter Ziff. 1 beschrieben, bewerkstelligen, welche dafür sorgen, dass die Zustellgeschwindigkeit des Druckbogens bezogen auf die vorgegebene Endposition soweit abgebremst wird, dass sie betragsmässig annähernd Null ist oder gegen Null strebt. Der endgültige punktgenaue Stillstand des Druckbogens wird dann unter Zuhilfenahme eines Anschlages bestimmt, auf welchen der Druckbogen mit seiner Remanenz Geschwindigkeit auftritt. Da diese Remanenz Geschwindigkeit mikroskopisch klein ausfällt, besteht keine Gefahr, dass die vordere Kante des Druckbogens in Zustellrichtung beim Anprall gegen die Anschlagfläche verletzt werden oder von dieser Anschlagfläche zurückfedern resp. zurückspringen könnte. Diese sanft vollzogene Endstellung des Druckbogens hat darüber hinaus den Vorteil, dass sich dieser ganz an den Verlauf der Anschlagfläche angleichen kann, wodurch daraus eine maximierte genaue Ausrichtung des Druckbogens gegenüber der Anschlagfläche resultiert.

Thus, according to the invention, several alignments can be provided for pure position-accurate braking in the sense of a precise standstill of the printed sheet in the infeed direction:

1. 1. The exact position braking in the sense of a precise standstill of the printed sheet is accomplished solely by braking force-releasing pulses and / or by further braking force applications. In the case of the latter means, this can be achieved, for example, by creating a negative pressure acting on the printed sheet and / or by using at least one mechanical element.
2. 2. The exact position braking in the sense of a precise standstill of the printed sheet can be achieved by braking force-releasing impulses and / or by additional braking force applications, as described above under item 1, which ensure that the delivery speed of the printed sheet is braked to the specified end position is that it is approximately zero in terms of amount or tends towards zero. The final precise standstill of the printed sheet is then determined with the aid of a stop on which the printed sheet occurs with its remanence speed. Since this remanence speed is microscopically small, there is no risk that the front edge of the printed sheet in the delivery direction will be injured when it hits the stop surface or spring back or spring back from this stop surface. could jump back. This gently completed end position of the printed sheet also has the advantage that it can adapt completely to the course of the stop surface, which results in a maximized, precise alignment of the printed sheet with respect to the stop surface.

The following procedure is relevant: The speed of the printed sheet is slowed down at approx. 10 cm in front of the stop by means of a printed sheet brake so that it only occurs with a small residual kinematic energy at the stop, with the speed of the printed sheet <1 m / s on impact amounts to. With such a top speed, no damage to the printed sheet is possible, and the printed sheet also does not experience any springback due to excessive impact speed.

The course of the delay in the delivery speed of the printing sheet can preferably be provided according to an exponential function or quasi (similar) e-function, with truncation of the original curve progression by another mathematical progression is also possible. Truncation is generally understood to mean the cutting off or severing of something, mostly in a figurative sense (truncation from Latin truncare; English truncation). As an example, it could be stated that the course of the exponential function is no longer monotonously continued at a certain point, but instead the continuation of the braking course is perceived by another mathematical function.

In both cases described, paragraphs 1 and 2, it applies that the dynamics of the combustion-triggering precautions must take into account the way in which the printed sheets are transported. If conveyor belts are used to transport the printed sheets, the control of all braking force-releasing provisions must be in operative connection with the kinematic force exerted on the printed sheets by the conveyor belts. The braking effect by the means provided should not be in collision with the kinematic forces exerted by the conveyor belts, although in certain constellations it cannot be ruled out that an at least partial superposition of the two forces (braking force and transport force) is deliberately sought.

1. a) Es lassen sich intermittierende, gleichmässige oder oszillierende bremskraftauslösende Impulse anbringen, welche die Bremskraft direkt, semi-direkt oder indirekt auf den Druckbogen anbringen. Solche Impulse lassen sich mit der nötigen Intensität und Kraftentfaltung vorzugsweise durch den Einsatz einer gesteuerten Luftzuführung erreichen.
2. b) Die bremskraftauslösenden Impulse lassen sich vorzugsweise durch pneumatische Luftimpulse oder reibungsauslösende Elemente bewerkstelligen, wobei auch autonom betriebene elektronisch oder hydraulisch Elemente zum Einsatz kommen können. Auch diese letztgenannten Elemente können eine direkte oder indirekte Bremskraft auf den Druckbogen ausüben.
3. c) Vorzugsweise erfolgen die pneumatisch betriebenen bremskraftauslösenden Impulse durch mindestens einen direkt auf den Druckbogen gerichteten Luftstrahl, der auf ein intermediär oberhalb des Druckbogens angeordnetes flexibles Element bläst, wobei dieses Element mit der Form eines Hebels direkt auf Grund des Luftstrahls nachgibt oder über eine Lagerung beweglich ist.
4. d) Wird die Hebelwirkung des genannten Elementes direkt umgesetzt, so ist beispielsweise von Vorteil, wenn dieses Element aus einem faserverstärkten textilähnlichem Band besteht, womit eine Nachgiebigkeit in Abhängigkeit seiner Federkonstante resultiert.
5. e) Wirkt der Luftimpuls beim Einsatz eines Hebels auf einen Hebelarm, kann die Normalkraft und infolgedessen die resultierende Bremskraft durch Hebelgesetz verstärkt werden.
6. f) Mit den beschriebenen Vorkehrungen lassen sich vorteilhaft auch asymmetrisch zusammengesetzte Falzbögen verarbeiten, ausgehend von der Tatsache, dass solche Falzbögen den Nachteil haben, dass die Masse links und rechts unterschiedliche Werte aufweist. Zu diesem Zweck kann erfindungsgemäss die Kraft des Luftimpulses und infolgedessen auch die daraus resultierende Bremskraft durch automatische Druckregler eingestellt werden. Dabei werden die notwendigen Einstellwerte automatisch von der Steuerung resp. von dem übergeordneten Prozessleitsystem errechnet und umgesetzt.
7. g) Die bremskraftauslösenden Impulse können gleichzeitig oder zeitunterschiedlich mit gleichen oder unterschiedlichen Bremskraftgrössen auf eine vordere und/oder eine hintere Kante des Druckbogens in Zustellrichtung wirken, womit bei dieser Vorkehrung gleichzeitig eine Glättung resp. Streckung des Druckbogens erreicht werden kann.

With regard to the technical nature of the braking forces as well as their integration and use in relation to a precise positioning according to the invention of the printed sheet in the delivery direction, the following relationships can be recognized:

1. a) Intermittent, uniform or oscillating braking force-releasing impulses can be applied, which apply the braking force directly, semi-directly or indirectly to the printed sheet. Such impulses can be achieved with the necessary intensity and power development, preferably through the use of a controlled air supply.
2. b) The braking force-releasing impulses can preferably be brought about by pneumatic air impulses or friction-releasing elements, whereby autonomously operated electronically or hydraulic elements can also be used. These last-mentioned elements can also exert a direct or indirect braking force on the printed sheet.
3. c) The pneumatically operated braking force-releasing impulses are preferably carried out by at least one air jet directed directly onto the printed sheet, which blows onto a flexible element arranged intermediately above the printed sheet, this element giving way in the form of a lever directly due to the air jet or movable via a bearing is.
4. d) If the leverage of the element mentioned is implemented directly, it is advantageous, for example, if this element consists of a fiber-reinforced, textile-like band, which results in flexibility depending on its spring constant.
5. e) If the air impulse acts on a lever arm when using a lever, the normal force and consequently the resulting braking force can be increased by the law of the lever.
6. f) With the measures described, it is also advantageously possible to process folded sheets that are asymmetrically composed, based on the fact that such folded sheets have the disadvantage that the dimensions on the left and right have different values. For this purpose, according to the invention, the force of the air pulse and consequently also the braking force resulting therefrom can be adjusted by automatic pressure regulators. The necessary setting values are automatically generated by the control resp. calculated and implemented by the higher-level process control system.
7. g) The braking force-releasing pulses can act simultaneously or at different times with the same or different braking force values on a front and / or a rear edge of the printed sheet in the delivery direction, whereby with this precaution at the same time a smoothing resp. Stretching of the printed sheet can be achieved.

Accordingly, the device for braking and precise positioning of a printed sheet in a processing machine has means which develop a pneumatic and / or mechanical braking force and / or some other type of frictional force on the printed sheet along the feed direction of the printed sheet.

This precise positioning of the printed sheet is related to the operational process of a downstream processing station and must then be aligned so that the precise positioning is closely interdependent with the operational needs of the downstream processing station.

In particular, the pneumatically operated braking force-releasing impulses and the frictional forces caused by negative pressure can be used optimally when it comes to generating intermittent, even or oscillating braking forces on the printed sheet.

For this purpose, a control unit can advantageously be provided which provides control profiles resulting from the queried operating parameters, it also being possible for control profiles stored as required to be called up.

The intermittent, uniform or oscillating braking force-releasing impulses on the printed sheet, which cannot only be achieved by supplying air, are due to a direct, semi-direct or indirect braking effect on the printed sheet designed so that the braking forces that can be achieved with it can be related to mechanically, electronically, hydraulically operated components.

Particularly when it comes to decelerating and positioning imprinted printed sheets, the application of a negative pressure acting on the lower surface of the printed sheet in the delivery direction proves to be particularly advantageous, since the scale formation formed in the printed sheet is not destroyed in an interfering manner, which is always to be feared if only a purely vertical or quasi-vertical air supply is provided. Such a negative pressure can also be regulated well, so that the friction introduced thereby can fine-tune the printed sheets in a stable position, whereby with this procedure it is not excluded that further complementary braking forces can be used.

Thus, a further possibility for targeted braking of the printed sheet along the feed direction is made available, which consists in creating a negative pressure on the underside of the printed sheet, at which the printed sheet is pressed onto the base by the resulting suction, and so for a provides further braking by friction.

Both the active air injection onto the printed sheet and its braking by the vacuum-induced suction can be operated both individually and in combination with one another, with intermittent regulation between the two also being possible.

If air-dependent braking forces are used, it is advantageous if each air-operated nozzle is individually controlled by a switching valve, taking into account the feed speed and the nature of the printed sheet.

A controlled interdependence between the individual switching valves increases the targeted effect of the air jets, so that proactive against further on the Operative incongruences resulting from printing sheets in the downstream processing operations Remedur can be created.

The invention also relates to a method for braking the printed sheet with precise positioning in the sense of a precise standstill in accordance with the above orientations 1 or 2, the operational processes of the downstream processing station being included in summary for a better understanding:
The air pressure required for braking is calculated on the basis of the specified production data such as the folding scheme, paper weight, paper width, section length and the information is sent to the automatic pressure regulator. The printed sheets can have different values on the left and right depending on the folding scheme.

The pressure accumulator in front of the pneumatic switching valve in the direction of flow is filled to the calculated pressure by means of a pressure regulator.

If the downstream processing station is a folding operation, the printed sheet entering / fed into the folding area is detected at the rear edge by means of a light barrier. At the same time, the light barrier is used to synchronize the folding blade with precise timing and thus compensates for any irregularities during the transport of the printed sheet.

On the basis of the triggered trigger signal, taking into account dead time and speed compensation, a signal to activate the pneumatic switching valve is triggered.

The air stored in the pressure accumulator is then suddenly released, whereupon the air nozzle emits a pulse-like blast of air.

The released blast of air can either act directly (unreinforced) on the printed sheet or indirectly (reinforced) on a lever (in the present case formed by a fiber-reinforced textile fabric), which transfers the force triggered by the blast of air to the printed sheet.

The printed sheet is pressed onto a table-like base and thus generates an inherent braking force that can be transmitted to the printed sheet through friction.

If necessary, a braking force can be exerted on the trailing edge of the printed sheet at the same time or at different times. Thus, the mass of the leading printed sheet part (kinetic energy) causes the material to stretch due to the energy released by the braking effect, which leads to a stiffening effect of the printed sheet.

The braking force dynamics are selected so that the printed sheet is safely braked in the sense of the two inventive alignments 1 or 2 shown above, or when it rests against the printed sheet stop or the folding blade takes over the printed sheet. When a printing sheet stop is operationally active, the folding knife penetration point can start slightly delayed.

However, it is a strong further aspect of the invention that the exact positioning of the printed sheet in the sense of a precise standstill can be achieved by the braking forces described and their control even without a stop.

After the air pulse has been emitted, the pneumatic switching valve is closed immediately and the pressure regulator fills the air reservoir again with the preset pressure and is available for the next cycle.

However, operation with an air reservoir is not indispensable: the cycle-related, pulsed delivery of a certain amount of air under a certain pressure can also be achieved through a dynamic control system, which directly ensures a continuous supply of compressed air.

The method according to the invention for braking the printed sheet with precise positioning can accordingly also be supplemented by activating a negative pressure acting on the printed sheet.

1. 1. Gegenüber herkömmlichen Lösungen zeichnet sich die Erfindung dadurch aus, dass praktisch keine mechanisch bewegten Teile im Einsatz stehen und somit praktisch keine Verschleisserscheinungen entstehen können, auch nicht bei hohen Taktzahlen.
2. 2. Die zur Erzeugung der kurzen Luftimpulse benötigten Schnellschaltventile sind erprobte Elemente und sind dementsprechend operativ stabil, dies im Gegensatz zu Bremsbürsten nach Stand der Technik, welche immer sehr genau auf die Papierdicke der Druckbogen eingestellt werden müssen, und somit auch einem ständigen Verschleiss ausgesetzt sind.
3. 3. Vorteilhaft ist es auch, dass die erfindungsgemässen Vorkehrungen zur Erzielung einer positionsgenauen Abbremsung im Sinne eines punktgenauen Stillstandes des Druckbogens durch die im Bereich des Falzschwertes an sich minimierte Platzverhältnisse nicht eingeschränkt werden, was im Staufall eine einfache Zugänglichkeit zur Behebung einer Havarie sicherstellt.
4. 4. Die Druckbogen bleiben während der beschriebenen Operationen von jeglicher Beeinträchtigung oder Verletzung verschont.

The main advantages of the invention can be summarized as follows:

1. 1. Compared to conventional solutions, the invention is characterized in that practically no mechanically moving parts are in use and thus practically no signs of wear can arise, even at high cycle rates.
2. 2. The quick-acting valves required to generate the short air pulses are tried and tested elements and are therefore operationally stable, in contrast to prior art brake brushes, which always have to be set very precisely to the paper thickness of the printed sheet and are therefore exposed to constant wear and tear .
3. 3. It is also advantageous that the provisions according to the invention for achieving precise braking in the sense of a precise standstill of the printed sheet are not restricted by the minimized space available in the area of the folding blade, which ensures easy accessibility for repairing an accident in the event of a jam.
4. 4. The printed sheets are spared any impairment or injury during the operations described.

Brief description of the figures

The invention is explained below with reference to the drawing, to which express reference is made with regard to all details essential to the invention and not highlighted in the description. All elements that are not essential for a direct understanding of the invention have been omitted; the same elements are provided with the same reference symbols in the various figures.

Figur 1

eine Gesamtübersicht einer Längsfalzvorrichtung mit Einbezug eines Transportbandes für die Zustellung von Druckbogen;

Figur 2

die Darstellung einer Abbremsung und Positionierung des Druckbogens im Zusammenhang mit der Anbringung eines Luftimpulses als Bremskraft;

Figur 3

die Anbringung einer Bremskraft auf ein intermediäres mechanisches Element

In the drawing shows:

Figure 1

a general overview of a longitudinal folding device with the inclusion of a conveyor belt for the delivery of printed sheets;

Figure 2

the representation of a deceleration and positioning of the printed sheet in connection with the application of an air pulse as a braking force;

Figure 3

the application of a braking force to an intermediate mechanical element

Ways of Carrying Out the Invention

Figure 1 shows the surroundings of a longitudinal folding device 100, which essentially consists of a longitudinal folding device 101, which can be operated with a folding blade 102. The figure also shows the configuration of the pair of folding rollers 103. The operation of this longitudinal folding device 101 is symbolized by the longitudinally folded printed sheet 104 shown. Of course, the folding of the printed sheets can also be done by a transverse folding device, not shown in detail take place, this being in operative connection with the longitudinal folding device 101 shown, or being able to be operated as an autonomous unit. The printed sheet 105 is brought in via conveyor belts 106 and brought to a standstill at the folding position 107, either via a first precaution, after which:
The exact position braking in the sense of a precise standstill of the printed sheet is accomplished solely by braking force-releasing impulses and / or by further braking force applications. In the case of the latter means, this can be achieved, for example, by creating a negative pressure acting on the printed sheet and / or by using at least one mechanical element.

Or about a second precaution, according to which

the precise position braking in the sense of a precise standstill of the printed sheet by braking force-releasing impulses and / or by further braking force applications, as described above, can be brought about, which ensure that the delivery speed of the printed sheet is braked so far in relation to the specified end position, and that it is approximately in terms of amount Is zero or tends towards zero. The final precise standstill of the printed sheet is then determined with the aid of a stop (not shown in more detail in the figures) on which the printed sheet occurs with its remanence speed.

Since this remanence speed is microscopically small, there is no risk that the front edge of the printed sheet in the delivery direction will be injured when it hits the stop surface or spring back or spring back from this stop surface. could jump back. This gently completed end position of the printed sheet also has the advantage that it can adapt completely to the course of the stop surface, which results in a maximized, precise alignment of the leading edge of the printed sheet with the stop surface.

The following procedure is relevant for this last-mentioned precaution:
The speed of the printed sheet is slowed down at approx. 10 cm before the stop, which is not shown in detail, but which is familiar to those skilled in the art, by applying braking force to such an extent that it only occurs with a small amount of residual kinematic energy at the stop, with the speed of the printed sheet <1 m on impact / s is. With such a top speed, no damage to the printed sheet is possible, and the printed sheet also does not experience any springback due to excessive impact speed.

The course of the delay in the delivery speed of the printing sheet can preferably be provided according to an exponential function or quasi (similar) e-function, with truncation of the original curve progression by other mathematical progressions is also possible. Truncation is generally understood to mean the cutting off or severing of something, mostly in a figurative sense (truncation from Latin truncare; English truncation). As an example, it could be cited that the course of the exponential function is no longer continued at a certain point, and the continuation of the braking course is perceived by another mathematical function in its place.

In both of the precautions described, however, it is true that the dynamics of the precautions triggering the combustion must take into account the way in which the printed sheets are transported. If conveyor belts are used for the transport of the printed sheets, a control unit 117 must take into account all the provisions that trigger the braking force in operative connection with the kinematic force exerted on the printed sheets by the conveyor belts. The braking effect should not be in collision with the kinematic forces of the conveyor belts due to the means provided, whereby in certain constellations it cannot be ruled out that an at least partial superposition of the two forces (braking force and transport force) is deliberately sought.

The figure also shows a trailing printed sheet 108, with which the cyclical operation of the longitudinal folding device 100 is to be shown.

The operation of such a longitudinal folding device in operative connection with precise positioning of the printed sheet 105 is as follows:
Based on the specified production data such as the folding scheme, paper weight, paper width, section length, the air pressure required for braking is calculated and the information is sent via the control unit 117 to the automatic pressure regulator, taking into account that, depending on the folding scheme, the print sheet on the left and right side has different values having;

Furthermore, based on the specified production data such as folding scheme, paper weight, paper width, section length, the air pressure required for braking is calculated to decelerate the printed sheet 105 and the information is sent via the control unit 117 to the automatic pressure regulator 109, taking into account that, depending on the folding scheme, the Press sheet can have different values on the left and right sides.

The amount of air is introduced onto the printed sheet by the air nozzle 110 shown, which acts directly. When calculating the required amounts of air, it is taken into account at the same time that a further amount of air could be required to neutralize any fluttering movements that may occur when the printed sheet 105 is drawn in, and this is also taken into account. Of course, it should then also be taken into account that even after the printing sheet 105 has been completely braked, further stabilizing air introduction onto the printing sheet 105 may be necessary.

The pressure accumulator 111 located upstream of a pneumatic switching valve in the flow direction is then filled to the calculated pressure by means of a pressure regulator 109.

The printed sheet 105 entering / fed into the folding area is detected at the rear edge by means of a light barrier, which is not shown in detail, this light barrier simultaneously serving to synchronize the folding blade 102 with precise timing, the operation of the light barrier also recognizing irregularities within the tape transport of the printing sheet 105 and using the Control unit 117 compensates.

On the basis of the triggered trigger signal, taking into account dead time and speed compensation, a signal to activate the pneumatic switching valve is triggered.

The air stored in the pressure accumulator 111 is then suddenly released, whereupon the air nozzle 110 releases a pulse-like blast of air which acts on the printed sheet 105.

The released blast of air can act either directly on the printed sheet 105 or on a lever (see Figure 2 , Item 112), which transfers the air blast and the resulting force to the printed sheet. Of course, a configuration can also be provided in which the air blast acts both on the printed sheet 105 and on the lever 112, with the direct and indirect braking force application also being intermittent and with different pulse strengths of the air pulses (see Fig Figure 2 , Item 114) can be controlled by means of the control unit 117.

During the delivery process and / or during the folding process, the pneumatically triggered forces force the printed sheet 105 onto a table-like one And then generates a braking force on the printed sheet through friction.

If necessary, an additional braking force can also be applied to the trailing edge of the printed sheet 105, simultaneously or out of phase, with the material stretching triggered by the braking effect resulting in a stiffening of the printed sheet 105.

The braking time (see Figure 3 , Item 115) is selected so that the printed sheet 105 is safely braked to 0, and, in a figurative sense, also when using a printed sheet stop, as described above. This specification can also be achieved if the braking of the printed sheet 105 to 0 has that fictitious fixed edge ( Figure 3 , Pos. 113) at which the folding blade 102 takes over the printed sheet 105 as intended. The detection of the printed sheet 105 by the folding blade 102 can therefore be coordinated in such a way that this coincides at the same time with the fictitious fixed edge 113 of the printed sheet end.

A possibility, not shown in more detail, for braking the printed sheet 105 in a precise position can be achieved by activating an additional braking force which is based on friction. This can be achieved by the formation of a negative pressure acting on the underside of the printed sheet, whereby this possibility can easily be used in cooperation with the other braking forces explained. Figure 2 also shows the folding position 116 of the printing sheet 105.

Figure 3 shows the geometric relationships and the resulting forces in the course of the braking of the printed sheet. Such values, namely the distances 230 and 240 as well as the forces F _impuls (200), F _brakes (210), F _normal (220) occurring during the braking process, are qualitative in nature and are used as a basis for controlled braking, whereby these values are parameterized for a control / regulation of the braking process is also possible.

After delivery of the air impulses ( Figure 2 , Pos. 114) the pneumatic switching valve is closed immediately and the pressure regulator 109 fills the compressed air reservoir 111 again with the preset pressure and is available for the next cycle.

Claims (24)

1. Device for braking and positioning a printed sheet (105) in a processing machine, wherein there is at least one means along the feed direction of the printed sheet which exerts a braking-force action on the printed sheet, and thus the positioning of the printed sheet is feasible in connection with the operational process of a downstream processing station (100, 101), characterized in that the device includes at least one first means which is designed for pneumatic braking-force triggering pulses acting on the printed sheet, and at least one second means for braking-force production, in that the first means (110, 114, 200) provides braking-force triggering pulses (112, 114) acting directly or indirectly on the printed sheet (105) that are pneumatic and/or caused by a mechanical element (112), in that the second means provides at least one additional braking-force generating frictional force (210, 220) acting on the printed sheet which, in the feed direction (210), generates the formation of a negative pressure force acting on the underside of the printed sheet, in that, by means of the first and/or second means, intermittent, uniform or oscillating braking forces are generable on the printed sheet, and in that the braking forces are guided by a control unit (117), which are operable with variable control profiles resulting from the retrieved operating parameters and/or by means of stored control profiles.
2. Device according to Claim 1, characterized in that the intermittent, uniform or oscillating braking forces are implementable by a direct, semi-direct or indirect effect on the printed sheet (105).
3. Device according to either of Claims 1 and 2, characterized in that the one braking force acting on the printed sheet from above effects an increase in the friction between a table-like base (106) and the printed sheet.
4. Device according to Claim 1, characterized in that the mechanical element for the exertion of a braking force is arranged autonomously or intermediately opposite the printed sheet, and the mechanical element is operable using the air supply.
5. Device according to Claim 4, characterized in that the mechanical element is designed in the form of a lever (112), which is made flexible by its spring constant or flexible via a bearing arrangement.
6. Device according to one of Claims 1 to 5, characterized in that the braking of the printed sheet is supplemented by a further braking force, which is focused on the rear edge of the printed sheet (105) in the feed direction.
7. Device according to one of Claims 1 to 6, characterized in that the downstream processing station comprises at least one longitudinal folding device (100) and/or transverse folding device.
8. Device according to Claim 7, characterized in that at least one folding device (100) is operable mechanically (102, 103) and/or pneumatically.
9. Method for operating a device for braking and positioning a printed sheet (105) in a processing machine, wherein there is at least one means along the feed direction of the printed sheet which exerts a braking-force action on the printed sheet, and thus achieves the positioning of the printed sheet in connection with the operational process of a downstream processing station (100, 101), characterized in that at least one first means (110, 114, 200) is operated for pneumatic braking-force triggering pulses (112, 114) on the printed sheet (105), in that at least one second means is operated for providing at least one braking-force generating frictional force (210, 220) acting on the printed sheet, in that intermittent, uniform or oscillating braking forces on the printed sheet are generated by the first and/or second means, and in that the braking forces are guided by a control unit (117), which is being operated with variable control profiles resulting from the retrieved operating parameters and/or by means of stored control profiles.
10. Method according to Claim 9, characterized in that the positioning is achieved with the effect of a precise stoppage of the printed sheet (105) by braking-force triggering pulses (112, 114) and/or by further braking-force applying means, wherein the latter means creating a negative pressure force acting on the printed sheet (105) and/or the action being brought about by the use of at least one mechanical element.
11. Method according to Claim 9, characterized in that the positionally accurate braking is provided with the effect of a precise stoppage of the printed sheet by means of braking-force triggering pulses (112, 114) and/or by further braking-force applying means, which are operated in such a way that the feed speed of the printed sheet (105) is braked in relation to the predefined end position to such an extent that its magnitude is approximately zero or tends towards zero.
12. Method according to Claim 11, characterized in that at approximately 10 cm before a stop surface arranged at the end, the speed of the printed sheet (105) is braked by means of braking-force applications to such an extent that the printed sheet (105) touches the stop only with a small kinematic residual energy.
13. Method according to Claim 11, characterized in that the predefined end position is determined by a stop, and in that when the printed sheet strikes the stop, the feed speed of approximately zero has a final speed of < 1 m/s.
14. Method according to Claim 11, characterized in that the course of the deceleration relating to the feed speed of the printed sheet is provided in accordance with an e-function or quasi-e-function.
15. Method according to Claim 14, characterized in that the course of the curve of the deceleration has at least one truncation.
16. Method according to one of Claims 9 to 15, characterized in that the intermittent, uniform or oscillating braking forces on the printed sheet are implemented by directly, semi-directly or indirectly acting means.
17. Method according to one of Claims 9 to 16, characterized in that the braking forces are powered by mechanically, electronically, hydraulically, pneumatically induced forces directed directly or indirectly at the printed sheet.
18. Method according to one of Claims 9 to 17, characterized in that the braking forces acting on the printed sheet produce an increase in the friction between a table-like base and the printed sheet.
19. Method according to one of Claims 9 to 18, characterized in that to increase the friction of the printed sheet in the feed direction, a negative pressure force acting on the underside of the printed sheet is provided.
20. Method according to one of Claims 9 to 19, characterized in that at least one of the braking forces acting on the printed sheet is supplemented during the feeding of the printed sheet by a further braking force, which acts on or in the region of the rear edge of the printed sheet.
21. Method according to one of Claims 9 to 20, characterized in that at least one braking force is used in connection with the shingling or shingle separation of the printed sheets transported in the feed direction.
22. Method according to one of Claims 9 to 21, characterized in that at least one braking force used for the braking of the printed sheet is subsequently used as a transverse fold brake against the printed sheet during the operational process in the downstream processing station.
23. Method according to one of Claims 9 to 22, characterized in that at least one pneumatically operated braking force is controlled by at least one nozzle of a control valve whilst taking into account the feed speed and the nature of the printed sheet.
24. Method for braking and positioning the printed sheet (105) in the feed direction and for retarding the printed sheet during the fold-in feed and/or against the fluttering movements that occur when the printed sheet is drawn in, comprising the following method steps:

    - on the basis of the specified production data such as folding scheme, paper weight, paper width, cut length, the air pressure needed for the braking is calculated and the information is sent to the automatic pressure regulator (109),

    - taking into account the fact that, depending on the folding scheme, the printed sheet has different values on the left-hand and right-hand side,

    - taking into account the fact that the neutralization of the fluttering movements that occur as the printed sheet is drawn in could necessitate a further quantity of air, and

    - taking into account the fact that a further quantity of air which is available for further stabilization following the complete braking of the printed sheet is planned in;

    - on the basis of the specified production data such as folding scheme, paper weight, paper width, cut length, to decelerate the printed sheet during the fold-in feed and/or against the fluttering movements that occur as a printed sheet is drawn in, the air pressure needed for the braking is calculated and the information is sent to the automatic pressure regulator (109),

    - taking into account the fact that, depending on the folding scheme, the printed sheet has different values on the left-hand and right-hand side;

    - the pressure accumulator (111) located upstream of the pneumatic control valve in the flow direction is filled to the calculated pressure by means of the pressure regulator (109);

    - the printed sheet running in/fed in to the folding area is detected at the rear edge by means of a light barrier, wherein this light barrier is used simultaneously to synchronize the folding blade (102) with precise timing,
    wherein the light barrier detects irregularities within the tape transport of the printed sheet and compensates for the same via the control;

    - based on the activated trigger signal, taking into account dead time compensation and speed compensation, a signal is triggered to activate the pneumatic switching valve;

    - the air stored in the pressure accumulator (111) is then abruptly released, whereupon the air nozzle (110) releases a pulse-like blast of air;

    - the released blast of air acts directly on the printed sheet or indirectly on a lever (112), which transfers the blast of air and the resulting normal force onto the printed sheet (105);

    - the printed sheet (105) during the feeding operation and/or during the folding process is pressed onto a table-like base and through this operation a braking force is generated by friction on the printed sheet;

    - if required, an additional braking force is exerted simultaneously or with a phase shift on the rear edge of the printed sheet, wherein the printed sheet is stiffened by the material stretching triggered by the braking action;

    - the braking time is selected so that the printed sheet is safely braked to 0, or when the printed sheet is immediately adjacent to the stop, or when the folding blade (102) takes over the printed sheet or when the operation is delayed during the folding process;

    - after the air pulse has been discharged, the pneumatic control valve is closed immediately and the pressure regulator (109) refills the air accumulator (111) with the pre-set pressure and it is available for the next cycle.

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