EP1493867A2 - Device, method and arrangement for pressing two parallel-axis, mutually drawable rollers in a device for producing and/or treating a web of material - Google Patents

Abstract

A parallel double-roller (14, 16) assembly spreads a coating of liquid or paste to a web (10) of paper or carton. The assembly has a jack (26) which applies a converging force to the rollers and a sensor (36) determining the force. The sensor (36) is esp. positioned in the compression force transmission system between the jack and rollers. The system has two or more compression transmission paths each incorporating a pressure sensor. The compression applied by each jack is individually variable. One of the rollers is fixed but rotates within a machine frame. The second roller rotates within the frame but moves in response to pressure from the jack (26) applied through a lever.

Description

The invention is concerned with the mutual pressing of a pairing from two paraxial rollers in a device for the production and / or treatment of a running web.

Roller pairings are widely used in machines on which Paper or cardboard or other material webs manufactured or treated become. By means of such roller pairings material webs, for example calendered, painted or printed. Regularly it gets big Attention to the pressure applied between the rollers of the pairing placed. The compliance with a certain pressure force is usually crucial for the outcome of the treatment the material web, be it, for example, the smoothing result in calendering or the wringing result when applying a glue or a pigment-containing Coating color.

From EP 0 978 589 A2 it is known that between a pair of rolls transmitted pressing force and in particular their axial distribution means Detecting sensors embedded in one of the rollers near the surface are in the mantle of the roller or on the mantle applied coating. Although in this way the line pressure between The rollers are recorded very accurately and in case of deviations from the desired values a corresponding control suitable Strength devices are made to provide a stronger or weaker contact pressure of the To effect rolling. The embedding of the sensors in the roll body has Of course, the disadvantage that this complicates the production of the roller and expensive. It must also be taken into account that from time to time Abrasion of the outer functional layer of the roller may become necessary to repair damage in the roll surface. Are the sensors close? this functional layer arranged or even embedded in this, so can This entails that the outer layer of the roller only on one small part of their strength is available for sanding and According to an early replacement of the roller may be required.

The object of the invention is therefore to provide a device of the generic type To develop the way so that the above problem can be avoided can.

To solve this problem, according to a first aspect of the Invention, the sensor means in the of the force generating means on the Rollers extending power transmission outside of rollers bodies arranged the two rollers. By laying the sensor means off the roller bodies of the rolls out the manufacture of the Rolling less expensive and costly. Because no sensors in the Rolling body must be embedded, the possibility is opened to access standard rollers. Also the occasional sanding The rollers can be made so regardless of the sensor means become. Nevertheless, the ruling between the rollers can continue Contact pressure can be measured directly, as the sensor means in the transmission path the pressing force are arranged.

If a roll body of a roll is mentioned here, then including essentially the (usually hollow cylindrical) barrel-shaped, usually coated with a covering of elastic or hard material Understand structures that forms the actual roller. Journals, which serve for the rotatable mounting of the roller are not to Rolled body counted.

It is basically conceivable that those of the force generating means provided force substantially completely on the over the rollers extending power transmission path as the only power transmission path is transmitted. However, it may also be provided that the of force provided to the force generating means on the rollers extending power transmission path and at least one further power transmission path branched. In this case, the sensor means in the over the rollers extending power transmission path after the diversion be arranged from the other power transmission path.

If several parallel power transmission paths for those of the force generating means Provided provided force, so there is an advantageous Possibility to influence the effective pressing force between the rollers in that the ratio of over the different Power transmission transmitted forces is changeable. These are in the further power transmission path preferably arranged stop means, which for changing the ratio of the over the different ones Power transmission transmitted forces are adjustable.

Basically, it is sufficient along the running over the rollers power transmission path only to measure the transmitted force in one place. This point can before the roller body of a first of the two Rolling or after the roll body of a second subsequent of the two Rolls lie. But it is also possible, a force measurement at the same time several places along the running over the rollers power transmission path make. For this purpose, the sensor means can at least a sensor arranged in front of the roller body of the first roller and at least one after the roller body of the second following roller arranged sensor include. The advantage here is that of the compared with different sensors can be, so that the sensors control each other, so to speak. The safety and accuracy of the force measurement can be so increase.

In a preferred embodiment of the invention is one of the two Rolls on a stand relative to this stationary, but rotatably mounted, wherein on the stand a rotatably supporting the other roller bearing lever is attached, which for mutual rapprochement of the two Rolling is pivotable relative to the stator. The power generating means engage the bearing lever in this embodiment.

The sensor means may then comprise at least one sensor, which is attached to the bearing lever or the stand. In the design of the bearing lever or stator and the positioning of the sensor is make sure that the sensor is just that force component detected, which is introduced into the rollers mating.

Alternatively or additionally, the sensor means may comprise at least one sensor comprise, which is arranged in a storage area of one of the rollers. For example, the sensor can be attached to a journal of the relevant Roller be attached. But it can also be a journal of the roller concerned enclosing bearing provided with the sensor be. In the latter case, the sensor can be integrated in the rolling bearing or be attached to an outer ring of the bearing. It is also conceivable that the sensor is mounted on a bearing housing, in which a a bearing journal of the respective roller enclosing bearings is included.

Furthermore, the sensor means may alternatively or additionally to the above indicated possible sensor locations comprise at least one sensor, which is housed in a separately manufactured sensor module, this sensor module between the stator or the bearing lever and a bearing kit for a journal on the stand or the Bearing lever held roller is installed. Such sensor modules are in Form mechanically self-contained load cells marketable available. For the storage of the rollers can then on standard, Standardized bearing kits are used, which reduces costs effect.

The sensor means may for force sensing at least one zug- and / or pressure-sensitive element, in particular a strain gauge, include. Such sensor elements are in a variety of configurations known and have proven themselves in use as robust, negligible and precisely proved. Of course you can also use other measuring principles based sensor elements are used, provided they are one for the Pressing force between the rollers to provide representative sensor signal are able to.

Appropriately, an responsive to the sensor means and the Force generating controlling electronic control unit provided which are for the regular maintenance of a predetermined setpoint the pressing force between the rollers is set up. It can the force generating means in the region of both axial ends of the roller pairing at least one independently controllable, in particular hydraulic Force device and the sensor means for independent Detecting the pressing force in both axial end of the Roll pairing may be formed. The control unit can then become such Control of the power equipment be set up over the axial extent the roll pairing is a substantially constant line pressure between the rollers results, as in many applications is desired. However, the control unit is not excluded to program so that in the two axial end of the Roller pairing gives different values of line pressure.

The device according to the invention is preferably for use in a Coating determined, in which the material web between the two Rolling is passed and at least one of the rollers for transfer the application medium is used on the material web.

According to a second aspect, the invention proceeds in the solution of abovementioned object of a method for adjustment the contact pressure of two approachable axis-parallel rollers in a device for the manufacture and / or treatment of a running Material web, wherein at least one of the rollers has a radially elastic Roll cover has.

According to the invention, it is provided that a distance-force characteristic is determined for the roller pairing, which has a relationship between the mutual center distance of the two rollers and the represents the pressure force transmitted between the two rollers, and that to achieve a desired pressing force of the rollers in the working mode the device an associated target value of the axial distance from the Distance-force characteristic determined and adjusted at the roller pairing becomes.

The invention deviates from the previous approach by the between the rollers transmitted pressing force not by means of pressure sensors detected and dependent on the sensor signals control of Power devices causes. Instead, she does the spring properties take advantage of the elastic reference of at least one of the rollers. It is based on the knowledge that - due to the flattening of the cover at Pressing the rollers - the mutual distance between the axles of the two rolls depending on the between the two rolls ruling pressure changes. It can therefore be a "spring characteristic" be determined for the roll pairing, the between the rolls transmitted pressing force in relation to the mutual center distance of Rolls sets. Should then be in working mode of the machine in which the roller pairing is used, a certain pressing force can be achieved, so must only be looked up in the spring characteristic, which associated Center distance at the roller pairing must be adjusted to to obtain this same pressing force.

The embedding of pressure sensors in one of the rolls is in the inventive Solution not required. Therefore can on standard standard rollers be used, which are considerably less expensive. Even the occasional grinding of the rollers can be performed easily are embedded in the rollers without the risk of being embedded Damage sensors by this grinding.

If it is mentioned here that the distance-force characteristic for different values of the pressing force different values of the center distance provides, so it is understood that the term center distance here only representative of any size stands for the mutual Center distance of the two rolls is representative. For example, the Distance-force characteristic instead of directly from the center distance one Position indication for the center distance of the rollers influencing provide adjustable component.

It is not excluded in principle, the distance-force characteristic derive theoretically and represent formulaically. Usually it will however, be easier to determine the distance-force characteristic Perform measurements in a calibration phase of the device. These measurements can be carried out in particular with rotating rollers as it has been shown that when rotating in the elastic Roller covering occurring Walk operations the spring characteristic of the roller pairing can influence. Therefore, it is recommended that the distance-force characteristic under conditions which are in accordance with the conditions in Working operation of the machine at least come close.

Appropriately, one is to determine the distance-force characteristic at least two value pairs of center distance and pressing force determine for different values of the pressing force. It is favorable if metrologically a zero point and an end point of the spring characteristic of the Roller pairing can be won. For determining the zero point, one can the value pairs are determined for an approach position of the rolls, in which the rolls are essentially mutual until making each other Contact are close to each other, but essentially no pressure is transferred between the rollers. The endpoint determination This can be done by having one of the value pairs for one between the rollers transmitted pressing force is determined, the at least approximately corresponds to a maximum pressing force for which the device is designed.

It is basically conceivable that the spring characteristic is substantially complete take. It saves effort, if only a few points The spring characteristic can be determined and they between these points is interpolated. To a good approximation, it can often be assumed be that the rolling mating shows a linear spring behavior. Very simply the spring characteristic can then be determined by linear interpolation become.

As already explained at the beginning, a post-processing of the Roller cover may be required to complete the roller surface again to smooth and rid of defects. For this purpose, the roll cover abraded until the roll surface is again perfect. For the Of course, the old spring characteristic can not be abraded be more valid. It is therefore recommended, after grinding the roll cover to determine the distance-force characteristic again.

It is conceivable, the determined from the spring characteristic setpoint value of the center distance to set once in the sense of a control, for example by means of a path-controlled actuator, but its compliance in the Work operation of the institution not to review. Then stay However, static or dynamic distance fluctuations of the axes the rollers unrecognized, for example, in the working mode of the machine by heat deformation, tension or contact vibrations can be caused. In order to take into account such influences To be able to establish a regulation in the working mode the device detects the actual axial distance of the rollers sensory and adjusted to the desired value of the center distance.

Frequently, the axial distance of the rollers in the region of both axial ends the roller pairing be adjustable independently. Although this opens up the possibility of a linearly changing in the axial direction To adjust line pressure between the rollers, it will work for most Use cases be desired, the center distances in the two axial Adjust end portions of the roller pairing such that over the axial Extension of the roller pairing a substantially constant line pressure between the rollers results.

In a preferred embodiment, the inventive method in a machine for coating a paper or board web performed, with the paper or board web between the rollers is passed and at least one of the rollers for transfer of a liquid to pasty application medium on the paper or board web serves.

The invention further relates to an arrangement for mutual pressing two axially parallel rolls in a device for manufacturing or / and Treatment of a running web, wherein at least one of Rolls having a radially elastic roll cover, comprising adjusting means, by means of which the two rollers along a approach path approachable to each other and adjustable in an approach state, in which a pressing force is transmitted between the rollers. These Arrangement is intended in particular to carry out the method of above type are suitable. According to the invention, the arrangement comprises a Memory unit for storing a pre-determined distance-force characteristic for the roller pairing, which is a relationship between the mutual center distance of the two rollers and the between represents the pressing force transmitted to the rollers, and one with the control unit connected to the control unit and the control means, which is designed to achieve a desired pressing force The rollers from the distance force characteristic an associated target Determine the value of the center distance and the setting of this target value to effect on the roller pairing. With regard to the advantages of the invention Arrangement is based on the above discussion of the invention Referenced method.

The arrangement may include sensor means for detecting the actual center distance the rollers, wherein the control unit on the sensor means responds and for the regular maintenance of the desired value of the Axle spacing is formed.

The center distance of the rollers can in the region of both axial ends of the Roller pairing be adjustable independently. The control unit is then preferably for such adjustment of the center distances in the formed on both axial end portions of the roller pairing that over the axial extent of the roller pairing is a substantially constant Line pressure between the rollers results.

One of the first rollers may be longitudinally opposite to the second roller be held on the approach path movable roll carrier. The Adjusting means can then act on the roller carrier attacking force generating means for introducing a force generating the pressing force in the roll carrier include.

The force provided by the force generating means can be in the Essentially serve completely to generate the pressing force. The to Provided force is essentially based on a single Transfer power transmission, which runs over the two rollers. Alternatively, that provided by the force generating means Force also be branched, and indeed on a first, the pressing force between the two rollers transmitting power transmission and at least one second power transmission path. In this training becomes part of the power generation equipment provided by Force on the first power transmission via the roller pairing over wear and another part of this force on the at least one second Transfer power transmission.

When the force provided by the force generating means in the Essentially completely on a single, over the two rollers extending power transmission path is transmitted, a change the axial distance of the two rolls and thus a change in the between the two rollers effective pressing force by appropriate Activation of the force generating means are brought about. If several parallel power transmission paths are provided, to which the of consists of the force generating means provided force exists an advantageous possibility for influencing the pressing force between the rollers in that the ratio between that on the first power transmission path transmitted force and that on the at least one second power transmission transmitted force is variable. This can be realized for example by stop means, which in the at least one second power transmission path are arranged and to Change in the ratio of the different power transmission paths transmitted forces are adjustable. The position of the slings then serves as a size, which for the mutual center distance the rolls is representative. It only needs to be determined which position of the sling means which value of the center distance the rolls corresponds. This connection is known to achieve a desired pressing force between the rollers only the stop means are brought into the appropriate position.

The stop means can at least one for common movement with the first roller along its approach path to the second roller arranged stop and at least one with respect to the axis of second roller fixedly arranged counter stop comprise. To the Force relationships between the various power transmission paths then can influence at least one of the components: stop and Counter stop be adjustable.

The arrangement according to the invention is preferably for use in a machine intended for coating a paper or board web. The Paper or board web is preferably between the rollers passed through, wherein at least one of the rollers for transfer of a liquid to pasty application medium on the paper or board web serves.

Fig. 1

schematisch eine Gesamtansicht eines Streichwerks mit einer Sensoranordnung zur Detektion der zwischen einer Walzenpaarung herrschenden Linienpressung,

Fig. 2

schematisch einen Lagerbereich einer der Walzen zur Erläuterung von Varianten der Sensoranordnung.

Hereinafter, some embodiments of the invention will be described in more detail with reference to the accompanying drawings. In it represent:

Fig. 1

1 is a schematic view of a coating unit with a sensor arrangement for detecting line pressure prevailing between a pair of rollers.

Fig. 2

schematically a storage area of one of the rollers for explaining variants of the sensor arrangement.

The coating unit shown in Fig. 1 is used for double-sided indirect application a liquid to pasty application medium, for example a pigmented paint or a surface glue, on a running Material web 10 made of paper or cardboard. The web 10 moves by an order nip 12 referred to in the jargon as nip which passes between two adjacently arranged rollers 14, 16 is formed. The rollers 14, 16 are parallel with their axes 18, 20 arranged to each other. One of the rollers - here the roller 16 - serves as so-called fixed roller, while the other roller - here the roller 14 - forms a so-called moving roller. This means that the roller 16 rotatable about its axis 20, but otherwise fixed in position, while the moving roller 14 is approachable to the fixed roller 16 and from this is removable. The fixed roller 16 is for this purpose at a fixed to the ground anchored machine stand 22 held. A swiveling on the machine stand 22 mounted bearing lever 24 carries the moving roller 14. For pivoting the bearing lever 24 and thus for approach and pressing the moving roller 14 to the fixed roller 16 serves a Power device assembly 26, which preferably at least one hydraulic Piston-cylinder unit 28 in the region of both axial ends of Roller pairing 14, 16 has. The power device assembly 26 is of a controllable electronic control unit 30 of the coating, expediently Independent controllability of the individual strength devices of the Power device assembly 26 will be given.

Each of the rollers 14, 16 has in the illustrated embodiment an elastic roll cover 128 and 130, the example of a rubber or plastic material. Within the scope of the invention Of course it is sufficient if only one of the rollers 14, 16 an elastic Reference. The other of the rollers can then, for example, a Wear steel or chrome sheath.

The coating medium with which the material web 10 is to be coated is initially in a manner not shown, but basically known manner applied to the rollers 14, 16. From there, the coating medium becomes then transferred to the web 10. Doctor blades 32, 34 are used for Dosage and equalization of the applied to the rollers 14, 16 Coating medium. Such squeegee units are well known in the art are known and require in connection with the present invention no further explanation.

Quantity and thickness of the applied to the web 10 medium are influenced by the prevailing in order gap 12 Niplast, the is the pressing force that is transmitted between the rollers 14, 16. Around To know this Niplast is the coating with a sensor arrangement equipped, which directly detects the transmitted pressing force. Dis Sensor arrangement is arranged in the transmission path of the pressing force and measures the latter before introduction into or / and after leaving the Rollers bodies of the pair of rollers 14, 16. Concretely, the sensor arrangement in the embodiment of FIG. 1, at least one force sensor 36th which is attached to the bearing lever 24 or the stand 22 and its sensor signal to the control unit 30 supplies. In principle, it is enough only one such force sensor 36 along the transmission path of the pressing force provided. It is in itself indifferent whether the force sensor 36 is mounted on the bearing lever 24 or on the stand 22, if he is aligned and positioned so that essentially only the detecting force component, but this completely passes through him. The choice of the stand 22 as a mounting location for the force sensor 36th can of course have the advantage that the wiring of the force sensor 36th does not have to be guided over a turning point, what with today available technology is not a serious problem. A preferred choice for the mounting location of the force sensor 36 may be Nevertheless, if the web 10 is not - as in Fig. 1 - straight into and out of the order gap 12, but they at least one of the rollers 14, 16 partially wraps around. Then the Force sensor 36 preferably on that of the components: bearing lever Mounted 24 and stator 22, the roller with less wrap through the web 10 carries. In this way, the influence of the Train to be minimized to the force measurement.

However, both the bearing lever 24 and the stator 22 with at least one force sensor 36 are provided, which is a control the measured pressing force by comparing the sensor signals possible power. Conveniently, the bearing lever 24 and the stator 22 axially on both sides of the pair of rollers 14, 16, each with a force sensor 36th be provided to at least approximately information about the axial Distribution of the Niplast win.

The force sensor 36 may, for example, from the outside on the bearing lever 24th or the stator 22 applied strain gauges be constructed which occur as a result of the mutual contact pressure of the rollers 14, 16 elastic deformations of the bearing lever 24 and der Ständers 22 detect. The interconnection of several such strain gauges in bridge circuits is from the prior art itself known.

Depending on the measured actual pressing force causes the control unit 30 a suitable control of the power device assembly 26 to a For example, by an operator by entering on a control panel Prescribed set pressure force and under a to maintain automatic regulation. The pressing force to be set becomes in most applications in both axial end regions the pair of rollers 14, 16 be equal, so that one over the machine width constant line pressure results. In addition to force determination For example, the control unit 30 may also be configured from the sensor signals to determine the vibration behavior of the roller pair 14, 1 6 and the power device assembly 26 in terms of vibration control head for.

The force provided by the power device assembly 26 may be in the essentially exclusively on the rollers 14, 16 as the only power transmission path be transmitted. However, the coating can be total stiffer and less prone to vibrations are made when the force provided by the power device assembly 26 on a plurality Power transmission paths is transmitted. For this purpose, dashed lines in Fig. 1 a pair of cooperating stopper body 38, 40 located, whose one is arranged on the bearing lever 24 and the other on the Stand 22 is arranged. One of the stopper body 38, 40 - here the Anchor body 38 - is controllable by means of a control unit 30 Positioning member 42, for example, a Spindelhubglieds, adjustable. For Accordingly, the force provided by the power device assembly 26 is available Two power transmission paths available: a first, over the rollers 14, 16 extends, and a second, via the stopper body 38, 40th runs. By adjusting the position of the Anschlagköpers 38 can thereby the ratio of transmitted over the two power transmission paths Forces and so the effective pressure force between the rollers 14, 16 to be changed.

The at least one force sensor 36 lies in the over the rollers 14, 16th extending power transmission path at a point after the diversion from the second power transmission path and before reconnection with the second power transmission path. In this way is from the force sensor 36 further directly the actual pressing force recorded, and any tensions or thermally induced deformations within the coating, the measurement result can not be falsified.

In operation of the coating is of the power device assembly 26th preferably always a maximum force applied to the bearing lever 24. The desired pressing force will then, depending on the delivered Sensor signal of the force sensor 36, by appropriate adjustment of the Stop body 38 is set. The further the stopper body 38 in FIG. 1 is adjusted to the right, the greater is the proportion of over the stop body 38, 40 transferred force at the available total force. As far as the latter remains unchanged, the pressing force then increases accordingly from. When adjusting the stopper body 38 to the left in Fig. 1 applies the reverse.

It is understood that on both axial sides of the roller pair 14, 16 each pair of such stopper body 38, 40 is arranged, these Pairs preferably independently adjustable by means of one positioning member 42 are.

In Fig. 2 are the same or equivalent components with the same Reference number provided as in Fig. 1, but supplemented by a lowercase letter. As in the following only to differences from the previous embodiment should be discussed for explanations of these Components referred to the preceding description of FIG. 1.

Fig. 2 shows an embodiment in which one or more, in detail not shown sensor elements, such as strain gauges, in a load cell 36a are housed, which is a mechanical completed, separate component that forms between the bearing lever 24a and a bearing kit 46a is installed, the storage of a axial bearing pin 48a of the roller 14a is used. (It is understood that the Bearing lever 24a and the roller 14a are chosen here only by way of example. Of course, such a load cell between the Machine stand and the other roller to be installed.) The bearing kit 46a has a bearing housing 50a and a rolling bearing received therein 52a with an inner ring 54a and an outer ring 56a. The load cell 36a, for example, a commercially available force measuring block be as described by the company FMS Force Measuring Systems AG, Switzerland, is sold. The use of the load cell 36a has the advantage that the sought force passes right through them and for the bearing housing 50a and the bearing 52a standardized standard components used can be.

As an alternative to a load cell and the bearing pin 48a could also a measuring bolt can be extended by one or more suitable Sensor elements are attached to it. This is shown in dashed lines in FIG Indicated 36b. Furthermore, it is possible such sensor elements in the bearing housing 50a to install. The bearing lever 24a could then be constructive remain unchanged. and for the Wälzlaaer 52a could turn on a Standard component be resorted to.

As another alternative measuring point for detecting the pressing force comes the rolling bearing 52a into consideration. Here can one or more sensor elements for example, attached laterally on the outer ring 56a become. The rolling elements of the rolling bearing 52a cause elastic under load Deformations of the outer ring 56a, which is a measure of the transmitted Are force and can be detected. Finally, it is conceivable Rolling bearing 52a to use with integrated force sensor, ie a bearing, already prepared by the manufacturer with suitable force sensing elements is. Without constructive changes, the bearings can be existing Schreichwerke then be replaced by such "measuring bearings".

As already mentioned above, the coating color with which the material web 10 is to coat, first in unspecified, but at known manner applied to the rollers 14, 16, in turn, the Transfer coating color to the material web 10. Doctor blades 32, 34 serve for dosing and homogenization of the rollers 14, 16 applied coating color. The squeegee unit 32 has a squeegee bar 136, in which a metering rod 138 is rotatably supported. The squeegee bar 136 is in turn attached to a pivot arm 140, which pivotally connected to the bearing lever 24. By means of another, is supported between the bearing lever 24 and the pivot arm 140 Schwenkantriebsanordnung 142, the pivot arm 140 can be moved to the Roller 14 approximates and so the squeegee bar 138 against the surface the roller 14 are pressed. Analogously, the squeegee works 34 a squeegee bar 144, a metering rod 146 and a s.dem Machine stand 22 pivotally mounted pivot arm 148 on, which by means of a between the machine stand 22 and the Swivel arm 148 supported pivot drive assembly 150 to the fixed roller 16 is approachable. The pivot drive assemblies 142, 150 are preferably each of at least one hydraulic piston-cylinder unit educated.

Amount and thickness of the applied to the web 10 color influenced by the order gap 12 prevailing Niplast, so the Pressing force which is transmitted between the rollers 14, 16. In mutual Pressing the rollers 14, 16 are their covers 128, 130 in Area of the job gap 12 compressed and flattened, bringing a Reducing the distance between the axes 18, 20 of the rollers 14, 16 goes along. In the elastic range of this compression of the covers is the mutual center distance, which is denoted by e in the figure, a Measure of the transferred pressing force and thus the Niplast in the order gap 12. This behavior of the roller pairing corresponding to a spring 14, 16 is used in the illustrated coating to in Prank operation to set a certain desired Niplast. For this purpose is in a previously determined spring characteristic, which determines the dependence of the Axial distance e of the transmitted pressing force indicates, looked up, which center distance must be set concretely to this desired To obtain pressing force. The spring characteristic is data technology stored in an electronic memory 152, on its memory contents a microprocessor-based electronic control unit 30 accesses. The technical data representation of the spring characteristic in the memory 152 can be a formulaic one. Frequently, however, the spring characteristic becomes tabular be stored in the form of a plurality of value pairs, wherein each of these value pairs for a value of the pressing force an associated Value of the center distance e or one representative of the center distance e Contains size.

To set the center distance e is used in the embodiment controlled by the control unit 30 positioning member 42, preferably is designed as an electric motor driven Spindelhubglied. The Positioning member 42 serves to adjust a relative to the machine stand 22 stationarily arranged first stopper body 38, softer to Cooperation with a fixed to the bearing lever 24 is arranged second stopper body 40 is determined. In operation of the coating the bearing lever 24 by means of the power device assembly 26 in Direction pivoted toward the fixed roller 16 until the two stopper body 38, 40 strike each other. The center distance e of the rollers 14, 16 hangs in this working position of the position of the first stop body 38 off. By adjusting the first stopper body 38 can thus the Center distance e to be changed. In operation of the coating the control unit 30 controls the positioning member 42 in accordance with the the spring characteristic information obtained so that the value of the center distance e, which corresponds to a desired niplast. This desired Niplast is the control unit 30, for example via a not shown in detail control panel communicated by an operator.

The determination of the spring characteristic takes place in an actual work operation of the coating previous calibration phase. It can For example, proceed as follows: First, a zero point the spring characteristic determined. For this purpose, the first stopper body 38th moved back by means of the positioning member 42 in the figure to the left. Then, the bearing lever 24 by means of the power device assembly 26 in the direction pivoted to the fixed roller 16 out until the rollers 14, 16 in the Substantially power transmission-free, ie without generating a Niplast touch. This condition may be, for example, by an operator be detected by means of a piece of paper, put them in the order gap 12 stops. When stationary rollers 14, 16 is the sought state then reached when the paper strip just through the order gap 12 pull through. With rotating rollers, the achievement can the sought state can be recognized by the fact that the rollers 14, 16 begin to pluck at the paper strip. As soon as the searched State is reached, the first stopper body 38 by means of the positioning member 42 advanced again until it is in contact with the second stop body 40 arrives. The contact is made by means of a sensor 62 detected, which may be, for example, a touch sensor, but also a force transducer. This position of the first stopper body 38 is then stored by the control unit 30. It represents one Value of the center distance e, in which essentially no pressing force between the rollers 14, 16 is transmitted, so the zero point of Spring characteristic.

After determining the characteristic zero, at least one additional one must be used Characteristic point be recorded at a defined niplast. This may for example be the end point of the spring characteristic, in which a maximum nial cast prevails, for which the coating is determined and designed is. To determine this further characteristic point is again the first Stop body 38 is moved back by means of the positioning member 42 until it out of reach of the second stopper body 40 is. Then it is through Activation of the power device assembly 26 such a force in the bearing lever 24 introduced that the roller 14 to generate a Niplast against the roller 16 is pressed. Considered by theoretical considerations The geometric proportions of the coating can be out the force provided by the power device assembly 26 without Further, the line load prevailing in the order column 12 is calculated, at least as long as the stopper body 38, 40 are out of contact and no force is transmitted between them. After using the Kraftgeräteanordnung 26 a defined Niplast is generated, is now the first stopper body 38 by means of the positioning member 42 again to the second Stop body 40 moves out until it comes into contact with the latter. The contact production is in turn detected by the sensor 62. The Position, the first stopper body 38 at the moment of contact making is different than in the zero point determination of the spring characteristic. As a result of the mutual contact pressure of the rollers 14, 16 are the Roll covers 128, 130 namely in the region of the order gap 12 something flattened, causing the rollers 14, 16 compared to the zero point of Spring characteristic have moved a little closer to each other. This means, that the center distance e of the rollers 14, 16 now slightly lower than in the Characteristic zero is. Also this position of the first stop body 38 is stored by the control unit 30 in communication with the corresponding niplast.

There are now two characteristic points available, by means of which the Control unit 30, the entire curve if desired, gradually can interpolate. Of course, more than two characteristic points be recorded in the calibration phase. Especially Almost the entire spring characteristic can be measured become. It is also understood that instead of the zero and the end point the spring characteristic any two other intermediate characteristic points recorded and to the basis of a subsequent characteristic interpolation can be made.

In operation of the coating is of the power device assembly 26th preferably always provided such a force that then, when the first stopper body 38 out of contact with the second stop body 40 and consequently no force on the stopper body 38, 40th Niplast maximum and thus the center distance e is minimal is. If a lower Niplast be set, so causes the control unit 30 based on the characteristic data stored in the memory 152 an adjustment of the first stopper body 38 by a corresponding Measure in the direction of the second stop body 40. This increases the center distance e between the rollers 14, 16, so that the flattening the roller covers 128, 130 in the application gap 12 becomes smaller and the Niplast decreases accordingly. Because of the power device assembly 26 provided force remains unchanged, the difference component between this provided force and that over the rollers 14, 16 transmitted force on the two stopper body 38, 40 transmitted. The total force provided thus branches into a first power transmission path which passes over the rollers 14, 16, and a second power transmission path, via the stopper body 38, 40 leads. The further the first stop body 38 in the figure to the right is moved, the greater is the over the stopper body 38, 40th transferred share of the total power provided. Corresponding the Niplast in the order nip 12 becomes smaller Niplast can therefore easily by appropriate adjustment of the first stopper body 38 are obtained.

Thermal influences, mechanical stresses and contact vibrations can cause the center distance e in the working mode of the coating changes. To detect such distance fluctuations, a distance sensor 64 may be provided; its sensor signals from the control unit 30 evaluated and, if necessary, in corresponding correction signals be reacted to the positioning member 42. In this way a control loop can be set up, which keeps the center distance e constant at a desired value. The distance sensor 64 may for example, be an optical sensor. Of course, too other sensor principles conceivable.

If the sensor 62, a detection of the stopper body 38, 40th transmitted force can, instead of a distance control also directly a force control will be established. Because the over the stopper body 38, 40 transmitted force with knowledge of the Kraftgeräteanordnung 26 total force provided directly to the Niplast can close in the order column 12, also the sensor signals the sensor 62 for controlling the position of the first stop body 38 are used.

The assembly of positioning member 42 and stop members 38, 40 is expediently on both axial sides of the roller pairing 14, 16 be provided, each positioning member 42 preferably independent is controllable. In this way, the center distance e on both axial Pages are set independently. This allows one adjusting line load changing in the order gap 12 in the axial direction, although in many applications a constant line load will be desired. At the same time this allows, occurring during operation Variations in the center distance e, which may only be local to one axial side occur, individually regulate.

It will now be an alternative approach to determine the spring characteristic described. Initially, only one axial side of the coating system will be used although the subsequent process goes without saying is performed on both axial sides. This alternative approach starts with that on the considered axial side of the coating the local first stop body 38 by means of the associated positioning member 42 is brought into a front, fully extended end position. Then, the roller 14 is pivoted to the roller 16 until the second Stop body 40 abuts against the first stop body 38. The front End position of the first stop body 38 is such that the Rollers 14, 16 do not touch each other when the two stopper bodies 38, 40 are in mutual attack. The force device assembly 26 is controlled so that exerted by her on the bearing lever 24 Force is maximum. By maximum force is meant that force which would result in the maximum niplast when the force is alone would be transmitted via the roller pairs 14, 16. However, when fully extended first stop body 38 of the rollers 14, 16 leading Kraftübertragungsweg is open, the of the Kraftgeräteanordnung 26th provided force alone transmitted via the stopper body 38, 40. The arranged in this power transmission sensor 62 is at the alternative approach described here as a force sensor. The force value, which he with fully extended first stop body 38 and maximum force of the power device assembly 26 is detected by the control unit 30 is stored.

The roller 14 is now moved back again, and by pressing the Positioning member 42, the first stopper body in a rear, full brought back end position. Subsequently, the roller 14 is again pivoted with maximum force of the power device assembly 26 to the roller 16 out. The rear end position of the first stop body 38 is set so that the second stopper body 40 is not against the first Stop body 38 abuts. In order gap 12, therefore, there is maximum Nip load. Now, by means of the positioning member 42, the first stopper body 38 advanced until it is in contact with the second stopper body 40th arrives. The contact production between the two stop bodies 38, 40 is detected from the signal of the force sensor 62, for example when the control unit 30 changes the measured force determines a predetermined value. The position of the first reached in this way Stopper body 38 is stored; it represents the end point of the spring characteristic is at the maximum niplast in order gap 12 prevails.

By actuation of the positioning member 42 then the first stop body 38 further extended. It takes over the stop body 38, 40 transferred power to. If the first stopper body 38 so far out that the force sensor 62 stored at the beginning Indicates force value, the positioning member 42 is stopped and the position of the first stopper body 38 stored. It corresponds to the zero point the spring characteristic. From the zero and end points of the spring characteristic determined in this way can then incrementally through linear interpolation Characteristic intermediate points are calculated.

The above-described alternative procedure for determining the Spring characteristic has the advantage that at the power device assembly 26 no different forces must be set, but that it is sufficient to set only the maximum force on the power device assembly 26, around both the characteristic zero point and the characteristic end point to investigate. In addition, the time required for the calibration of the coating, because only a reversal of the travel direction of the positioning member 42 is required.

External forces (e.g., weight forces of various components of the Coating, such as a paint feed) can lead to skew the rollers 14, 16 lead relative to each other, to compensate for it it is necessary that the power device assembly 26 on the two axial Pages of the coating different forces on the bearing lever 24th exercises. To take account of such external influences already during calibration, may be the alternative approach described above be modified to determine the spring characteristic in the following manner. At the beginning of the calibration process, the first two stop bodies 38 on both axial sides of the coating in its front end position driven, and the power device assembly 26 is driven so that they have the same maximum force on both axial sides of the coating provides. Then, on each axial side by means of the respective Force sensor 62 measured which force for the respective pair of first and second stopper body 38, 40 is transmitted. Is the first roller 14 aligned exactly parallel to the second roller 16, so these are force values equal. On the other hand, is an inclination of the first roller 14 relatively to the second roller 16, different force values result. The Both force values thus determined are stored by the control unit 30. Then - as before - the first stopper body 38 in their moved rear end position and from this rear end position to the contact production with the respectively associated second stopper body 40 again extended. Subsequently, the first stopper body 38 on the one axial side on which the greater force value was initially measured, extended as far as towards its front end position, until between the force values measured by the force sensors 62 a difference which equals the difference between the initially measured and stored force values. Once this condition is reached, it is the uneven mutual contact pressure of the rollers 14, 16, by the original force difference was caused balanced. It Now the position of each of the first stopper body 38 is stored; she corresponds to the maximum niplast.

Then both first stopper body 38 together towards their front end position moves until the force sensors 62 for the respective Show axial side originally stored force value. The two Positioning members 42 are then stopped simultaneously and their position or that of the first stopper body 38 as a zero Niplast, i. when Characteristic zero point defined and saved.

In the present example case it was assumed that the power device arrangement 26 is force-controlled. However, if a path-controlled embodiment the power device assembly 26 is selected, for example using a spindle drive, so can on the stopper body 38, 40 and the positioning member 42 are omitted and a desired Center distance e instead directly with the help of Kraftgeräteanordnung 26 are set. In this case, there would be only one power transmission path present, which leads over the rollers 14, 16. In contrast, Providence has at least one further transmission path, as in illustrated embodiment by the positioning member 42 and the Stopper body 38, 40 is formed, the advantage that the coating altogether stiffer and thus less susceptible to vibrations can be.

In summary, the invention allows a very precise adjustment a desired Niplast, especially if this comparatively is low. Due to the high precision of the niplaste setting can be used independently of the roll diameter, the roll cover thickness, from the roll hardness and possible tension a qualitative achieve high quality painting result, whereby the high precision of the Niplasteinstellung helps to contact vibrations between the Keep rolls low. The possibility of even very low niplasts Precise adjustment also helps in the so-called "Misting" reduce misting of the coating color at the outlet of the Called contract gap and can affect the strike result.

Claims (21)

Device for the mutual pressing of two axially parallel arranged, approachable rollers (14, 16) in a coating unit for surface application of a liquid to pasty application medium on a moving material web (10), in particular of paper or cardboard comprising Force generating means (26) for providing a force which is at least partially transferable in a force transmission path extending over the rollers (14, 16) to generate a pressing force between the rollers (14, 16), and Sensor means (36; 36a; 36b) for detecting the pressure force between the rollers (14, 16), characterized in that the sensor means (36; 36a; 36b) are arranged in the power transmission path extending from the force generating means (26) via the rollers (14, 16) outside of roller bodies of the two rollers (14, 16). Device according to claim 1,
characterized in that the force provided by the force generating means (26) branches to the force transmission path passing over the rollers (14, 16) and at least one further force transmission path and in that the sensor means (36) extends in the over the rollers (14, 16) Power transmission path are arranged after the diversion of the further power transmission path. Device according to claim 2,
characterized in that the ratio of the forces transmitted via the different power transmission paths is variable. Device according to claim 3,
characterized in that stop means (38, 40) are arranged in the further force transmission path, which are adjustable to change the ratio of the forces transmitted via the different power transmission paths. Device according to one of claims 1 to 4,
characterized in that the sensor means (36, 36a, 36b) comprise at least one sensor (36) which, relative to the force transmission direction of the force transmission path extending over the rollers (14, 16), in front of the roller body of a first (14) of the two rollers (14 , 16) is arranged. Device according to one of claims 1 to 5,
characterized in that the sensor means (36; 36a; 36b) comprise at least one sensor (36) which, relative to the force transmission direction of the force transmission path extending beyond the rollers (14, 16), faces the roller body of a second following (16) of the two rollers (14 , 16) are arranged. Device according to claims 5 and 6,
in that the sensor means (36; 36a; 36b) comprise at least one sensor (36) arranged in front of the roller body of the first roller (14) and at least one sensor (36) arranged downstream of the roller body of the second following roller (16). Device according to one of claims 1 to 7,
characterized in that one (16) of the two rollers (14, 16) on a stand (22) relative to this stationary, but rotatably mounted, that on the stator (22) a the other roller (14) rotatably supporting bearing levers ( 24) is mounted, which is pivotable relative to the stator (22) for mutual approach of the two rollers (14, 16), and that the force generating means (26) on the bearing lever (24) engage. Device according to claim 8,
characterized in that the sensor means (36; 36a; 36b) comprise at least one sensor (36) mounted on the bearing lever (24) or the stand (22). Device according to claim 8 or 9,
characterized in that the sensor means (36; 36a; 36b) comprise at least one sensor (36b) which is arranged in a bearing region of one of the rollers (14a). Device according to claim 10,
characterized in that the sensor (36b) is mounted on a bearing journal (48a) of the respective roller (14a). Device according to claim 10,
characterized in that a bearing journal (48a) of the respective roller (14a) enclosing rolling bearing (52a) is provided with the sensor. Device according to claim 12,
characterized in that the sensor is integrated in the rolling bearing (52a). Device according to claim 12,
characterized in that the sensor is attached to an outer ring (42a) of the rolling bearing (52a). Device according to claim 10,
characterized in that the sensor is mounted on a bearing housing (50a) in which a bearing journal (48a) of the respective roller (14a) enclosing the rolling bearing (52a) is received. Device according to one of claims 8 to 15,
characterized in that the sensor means (36; 36a; 36b) comprise at least one sensor housed in a separately fabricated sensor module (36a), said sensor module (36a) interposing between the stator or bearing levers (24a) and a bearing assembly (46a ) is mounted for a bearing journal (48a) of the roller (14a) held on the stand or the bearing lever (24a). Device according to one of claims 1 to 16,
characterized in that the sensor means (36; 36a; 36b) for force sensing comprise at least one tensile and / or pressure-sensitive element, in particular a strain gauge. Device according to one of claims 1 to 17,
characterized by an electronic control unit (30) responsive to the sensor means (36; 36a; 36b) and controlling the force generating means (26) arranged to maintain a predetermined set value of the pressing force between the rollers (14,16) in a controlled manner. Device according to claim 18,
characterized in that the force generating means (26) in the region of both axial ends of the pair of rollers (14, 16) each comprise at least one independently controllable, in particular hydraulic force device (28) and the sensor means (36; 36a; 36b) for independent detection of the pressing force are formed in both axial end regions of the roller pairing (14, 16). Device according to claim 19,
characterized in that the control unit (30) is arranged for controlling the force devices (28) such that a substantially constant line pressure between the rollers (14, 16) results over the axial extension of the roller pairing (14, 16). Device according to one of claims 1 to 20,
characterized in that the material web (10) between the two rollers (14, 16) is guided and at least one of the rollers (14, 16) for transferring the application medium on the material web (10) is used.

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