EP1666396B1 - Apparatus for folding flat articles - Google Patents

Abstract

Folding device has bag folding unit with adjustable bag stopper (7). An adjuster (16) is provided for orientation of bag stopper. A sensor (17) generates signals characterizing the process of impinging of edges of work piece on stopper bag. Controller (21) controls adjuster in interpretation of signals in such that the edge arrives to a momentary stop within a time lag according to desired value.

Description

The invention relates to a device for folding flat workpieces. Such a device is for example off DE 197 47 997 A1 known. The Taschenfalzeinrichtung typically comprises three operationally continuously rotating rollers forming a pair of transport rollers and a Falzwalzenpaar and this are usually arranged axially parallel under horizontal alignment and have a common transport roller pair and the Falzwalzenpaar roller, which forms a transport nip with a transport roller and a folding gap with a folding roller. The three rolls a folding pocket with a pocket mouth and an adjustable pocket stop is assigned such that a transport gap passing flat workpiece - usually a previously printed sheet - runs through the pocket mouth in the folding pocket and impinges with the leading edge of the workpiece on the pocket stop. After the impingement of said leading edge on the pocket stop arises on the workpiece as a result of the continuous rotation of the transport roller pair formed between the transport nip and the pocket mouth buckling fold, which then passes into the folding nip, which forms a fold in the buckle fold. The resulting signature is then transported out by the Falzwalzenpaares with vorseilendem Falzbruch from the folding gap.

The distance of the pocket stop from the mouth of the pocket is decisive for the position of the fold break, in particular with regard to the aforementioned leading edge. Therefore, in the known device mentioned Adjusting means provided in the form of a servomotor, by means of which the pocket stop is adjustable by changing its distance from the pocket mouth.

The not belonging to the pair of transport rollers roller of the folding roller pair of the known device is deflected by the passing of the folding gap signatures. Corresponding deflections are detected by means of a sensor whose signals are combined in a control unit with measured values for the conveyed arc length between the inlet of the sheet in the device and the fold, so that in incorrect position of the fold break with respect to, for example, the leading edges of the arc control unit in turn the mentioned servomotor to adjust the pocket stop in terms of a correction of the position of the fold breakage.

One out DE 100 23 933 A1 Known folding pocket has a pocket stop, which in addition to adjusting its distance from the pocket mouth is rotatable about a point which lies in the longitudinal center of the pocket stop.

This adjustment of the orientation of the pocket stop is provided in the event that said leading edge of a sheet to be folded is not exactly orthogonal to the transport direction of the sheet. To adjust the pocket stop this known folding pocket a so-called reference travel is provided. This is obviously understood a probeweiser operation of Taschenfalzeinrichtung in which a first sheet folded and measured before the folding of another sheet with respect to the position of the fold break and based on the measurement result of the pocket stop on adjusting means in the form of a respective spindle drive at a respective end of the pocket stop and one of each Stepper motor for driving the respective spindle drive adjusted and this process is repeated until there is an orientation of the pocket stop, which provides a correct position of the fold breakage.

From the DE 39 38 534 A1 a pocket folding machine is known, which has adjustable stops. During the folding process, a folding sheet striking the stop strip of the folding machine is registered in its position by sensors and its signals are forwarded to the control computer of the folding machine. From the registered measured values, the control computer forms an average value of the deviation from the predetermined reference fold line. In case of deviations, this mean value is compensated by the control computer and two stepper motors are actuated for adjusting the stop bar in the folding machine.

The invention has for its object to provide a device for folding flat workpieces in such a way that in addition to retrofitting when changing the format of the workpieces required setup work by an operator can be dispensed with in the event that the workpieces are not exactly trimmed orthogonal.

This object is achieved with a device for folding flat workpieces according to claim 1.

If signatures of high quality are to be created with regard to dimensional accuracy, the control is preferably designed such that it reduces the delay time to a minimum.

The delay time depends on the orientation of said leading edge of the workpieces and the orientation of the pocket stop. With matching orientation of the anticipatory Edge and the pocket stop results in a minimum of the delay time. In this case, theoretically all points along the leading edge meet simultaneously on the pocket stop (in this case, it is assumed that the pocket stop has a closed stop face). Regardless of the orientation of the leading edge and the pocket stop results in each impact of this edge on the pocket stop a noise, among other things depending on the above orientations varying sound pressure levels. However, in the case of a minimum delay time, the occurring sound pressure level always assumes a maximum value. In this respect, the sound pressure, although different workpieces result in different measured values for a respective maximum value when hitting different pocket stops with different speeds, is a particularly suitable measurement variable in order to generate the signals of the occurrence of the respective leading edge on the pocket stop by means of a sensor system. The sensor provided for this purpose only requires a sound pressure sensor.

In the case of generating signals that characterize the process of impingement of each leading edge of the workpieces on the pocket stop, by means of a sound pressure level measurement, the requirements for the control means controlling the control means, in particular, are relatively low, if as the target value of the delay time is a time window is provided, the extent of which is at least almost equal to zero. Since, in this case, the measured value of the sound pressure level detected by the sensor substantially reaches a maximum, the control does not require any stored therein - depending on a plurality of parameters - target value and it is here only designed to evaluate the means of the sensor generated sound pressure levels corresponding signals to control the actuating means such that, while approximating the orientation of the pocket stop to those of each leading edge of the workpieces ultimately at least almost a maximum value of the impact of the workpieces occurring on the pocket stop sound pressure level results. In particular, the controller is designed so that an adjustment movement of the adjusting means initiated by the latter is maintained when an increase in the sound pressure level is associated therewith. Otherwise, the control causes a reversal of an initiated adjustment movement.

For this purpose, the controller compares successive signals that characterize the process of the impact of each leading edge of successive workpieces on the pocket stop in the case of generating these signals by means of a sound pressure sensor comprehensive sensor with regard to the height of the successive impact of the workpieces on the In a preferred embodiment, it causes the actuating means, after the start of an actuating movement thereof and an optionally reversed direction of the actuating movement to standstill, if the comparison of said signals shows that the sound pressure level is at a level which is at least almost one order-specific maximum.

In a preferred development, the controller is also able to store a nominal value signal representing the named level of the sound pressure level together with order-specific data (format, basis weight and the like of the workpieces) for similar follow-up orders.

In a modified form of the control, empirically determined order-specific nominal value signals are stored from the outset.

In an alternative embodiment, the sensor generates the process of hitting the respective leading edge of the workpieces on the pocket stop characterizing signals from frequency spectra of the impact of the workpieces on the pocket stop caused sounds and the device includes a frequency analyzer, which actual value spectra with in compares the setpoint value spectra stored in the control. The adjusting means are controlled in dependence on the respective result of the comparison in the sense of an approximation of the spectra supplied by the sensor to the respective stored order-specific nominal value spectrum. This may in turn give rise to a reversal of an initially initiated adjusting movement of the actuating means. For this signal evaluation, a fast-working, digitally operating control is provided, which is real-time capable in a preferred embodiment.

Instead of an embodiment of the control for the deposit of desired value spectra this is self-learning in a modified embodiment and works just as in the case of the previously described generation of sound pressure levels corresponding signals on the principle of maximizing the actual values.

In the embodiments set forth so far, the sensor generates the process of striking the respective leading edge of the workpieces on the pocket stop characterizing signals in contrast to a later explained in detail embodiment of events that are caused by the contact of the workpieces with the pocket stop. These events include not only the creation of noise but also Movements and elastic deformations of the pocket stop. However, these movements as well as elastic deformations of the pocket stop are not part of the present invention.

In a preferred längsmittensymmetrischen connection of the pocket stop to the device and with respect to the processing direction of the Taschenfalzeinrichtung longitudinally alignment of the workpieces of different formats - as can be provided for the entry into a first folding pocket - can be by means of a suitably designed sensors also from the mentioned movement processes and Shape changes also generate the process of impingement of the respective leading edge of the workpieces on the pocket stop characterizing signals, which are then relatively easily evaluated by means of a control due to the measures taken in terms of symmetry.

As already indicated, the extension of the time window for the delay time within which the leading edge of the respective workpiece momentarily comes to a halt when hitting the pocket stop approaches the more zero the more precisely the orientation of the stop surface of the pocket stop that of the leading edge corresponds to the respective workpieces.

In the ideal case of the proposed device, the conformity of the orientation of the stop surface of the pocket stop with that of each leading edge of the workpieces are in the case of taken with a view to the symmetry measures the movement processes and changes in shape of the pocket stop as a result of the impact of the workpieces on this symmetrical to the longitudinal center of the pocket stop.

Depending on the configuration of the device, said sensor system comprises encoders for measured values of movement processes or elastic deformations of the pocket stop and generates corresponding signals which characterize the process of impingement of the respectively leading edge of the workpieces on the pocket stop, which signals are then evaluated by the controller and used to control the Adjusting means are used in the sense that they adjust the pocket stop to an orientation in which the measured values arise symmetrically at least substantially as the longitudinal center of the pocket stop.

Depending on their equipment, the sensors detect actual values of movement processes or changes in shape at locations symmetrical with respect to the longitudinal center of the pocket stop. The evaluation of the signals by the control takes place on the basis of the comparison of the measured values obtained at the symmetrical locations.

The center-symmetric actual value detection enables the controller to memorize the setting means in the right direction from the outset. The controller stops the actuating means when the orientation of the pocket stop meets the specifications.

In an alternative embodiment of the device, the signals characterizing the process of impingement of the respectively leading edge of the workpieces on the pocket stop are already generated on the way of the workpieces in the direction of the pocket stop. For this purpose, the sensor system is equipped with detectors, by means of which the orientation of a respective on the pocket stop to moving leading edge of the workpieces characterizing orientation signals are generated, and the controller is designed to evaluate these orientation signals the adjusting means in the sense of an alignment of the orientation of the pocket stop to those of the detected edge of the workpieces to control.

Orientation signals characterizing the orientation of this edge in turn allow the control to impart an actuating movement in the right direction to the adjusting means from the outset and to set the actuating means to a standstill when the orientation of the pocket stop meets the specifications.

The subject invention is shown in the accompanying drawings partly in schematic and partly in a symbolic representation, identical components are assigned the same reference numerals.

Figur 1

ein Schema einer Vorrichtung zum Falzen flacher Werkstücke in Form einer Taschenfalzmaschine mit lediglich beispielhaft vier Taschenfalzeinrichtungen,

Figuren 2 bis 5

jeweils einen Rahmen und einen mittels Stellmitteln verstell- und justierbaren Taschenanschlag einer Falztasche mit symbolhaft dargestellten unterschiedlichen Ausgestaltungen einer Sensorik, welche den Vorgang des Auftreffens der jeweils vorauseilenden Kante der Werkstücke auf den Taschenanschlag charakterisierende Signale generiert, und einer Steuerung, welche unter Auswertung der Signale die Stellmittel ansteuert.

In the drawings shows:

FIG. 1

a diagram of an apparatus for folding flat workpieces in the form of a pocket folding machine with only four exemplary Taschenfalzeinrichtungen,

FIGS. 2 to 5

in each case a frame and an adjustable by means of adjusting means and adjustable pocket stop a folding pocket with symbolically represented different embodiments of a sensor, which generates the process of impingement of each leading edge of the workpieces on the pocket stop characterizing signals, and a controller, which under evaluation of the signals Actuator drives.

In the Fig. 1 schematically reproduced Taschenfalzmaschine 1 is exemplary designed for four folds on flat workpieces 2 and has four folding pockets 3 to 6, of which each one - only reproduced in the case of folding pocket 3 - adjustable pocket stop 7. A roller pair - formed from a transport roller 8 and a transport and folding roller 9 - conveys the in the direction of in Fig. 1 right arrow in unspecified manner delivered flat workpieces 2 in the first folding pocket 3, until the already mentioned upset fold forms when hitting the leading edge 2.1 of the workpiece 2 to the pocket stop 7, then in the folding gap between the transport and folding roller. 9 and a folding and transporting roller 10 in which the first folding takes place. The folding and transport roller 10 transported together with the transport and folding roller 9, the resulting signature 2 'with vorseilendem fold break in a second folding pocket 4 and it runs a similar process from where the formation of folds in a folding gap between the folding and transport roller 10th and a folding and transporting roller 11 takes place, which in the further course together with the folding and transport roller 10 performs the function of a transport roller, etc., until the workpieces finally reach the last folding pocket - here the fourth of four - and a last pair of rollers 12 received a final fold.

A pair of knife shafts 13 for trimming the signatures 2 'and, at the same time, a removal roller 14 adjoin the last folding pair of rollers 12. The pocket stops 7 of all folding pockets 3 to 6 are adjustable to the leg lengths of the multiple folds from a workpiece successively resulting signatures. In any case, the pocket stop 7 of the first folding pocket 3 is moreover adjustable to different orientations, since in the first folding pocket 3, the unfolded flat Workpieces 2 may have obliquely to the rollers of the device extending leading edges 2.1.

The in the FIGS. 2 to 5 In the case of a pocket folding machine with a plurality of pocket folding devices, reproduced examples of execution and equipment relate in particular to a first of these and differ only with regard to the configuration of the mentioned sensors and the mentioned control. Incidentally, the embodiments are mechanically similar insofar as each one Falztaschenrahmen 15, an adjustable and adjustable pocket stop 7 and respective at a respective end portion of the same attacking, the Falztaschenrahmen 15 arranged adjusting means 16 are provided.

The adjusting means 16 are exemplary of the model of DE 100 23 933 A1 known fold pocket formed in the form of two spindle drives and thus both suitable for setting the pocket stop 7 on the leg lengths of respective signatures and not shown in detail for adjusting the orientation of the stop surface of the pocket stop 7, ie to approximate this orientation to those of each leading edge 2.1 of the workpieces 2. For a more detailed explanation of the actuating means 16 is so far on DE 100 23 933 A1 directed.

To generate signals that characterize the process of impingement of the respective leading edge 2.1 of the workpieces 2 is - as already indicated - depending on the embodiment according to one of FIGS. 2 to 5 a sensor 17 or 18 or 19 or 20 is provided, which preferably the signals in digitized form to a depending on the embodiment according to one of FIGS. 2 to 5 trained controller 21 or 22 or 23 or 24, which then - as stated to the embodiments set - the actuating means 16 controls.

The Fig. 2 indicates the case that the sensor 17 includes a sound pressure sensor 17.1, which is exemplified by a commercially available microphone. This is preferably arranged in the immediate vicinity of the pocket stop.

In the case of the detection of frequency spectra in the generation of signals that characterize the process of impact of the workpieces 2 on the pocket stop, a sensor system is provided, which also includes a commercially available microphone for detecting actual value spectra and in which a frequency Analyzer is integrated.

The embodiments according to Figures 3-5 are not part of the present invention.

The Fig. 3 shows the case that the sensor 18 is equipped with encoders 18.1 for measured values of motions of the pocket stop 7 due to the impact of the workpiece 2 on this. The encoders 18.1 are represented for example by commercially available acceleration sensors. As such, they are in any case firmly connected to the pocket stop 7 and are preferably arranged symmetrically with respect to their longitudinal center.

In Fig. 4 the case is shown that the sensor 19 comprises sensors 19.1 for measured values of elastic changes in shape of the pocket stop 7. The encoders 19.1 are represented, for example, by strain gauges, they are preferably arranged symmetrically to the longitudinal center of the pocket stop 7 and detect in the case of their arrangement according to Fig. 4 on the Falztaschenrahmen 15 for the elastic shape changes of the pocket stop 7 representative shape changes, ie they detect the changes in shape of the pocket stop 7 indirectly.

According to Fig. 5 the sensor system 20 is equipped with detectors 20.1 by means of which the orientation of a respective leading edge 2.1 of the workpieces 2 characterizing the pocket stop 7 is generated. For this purpose, suitable detectors and their arrangement are, for example, in DE 199 50 603 A1 explained in more detail. This can be in the case of a realization of a sensor according to Fig. 5 be resorted to.

Preferably, the detectors 20.1 are adjustably arranged in the longitudinal direction of the pocket stop, in order to be usable for different formats of the workpieces 2.

In the Fig. 5 exemplary placement of the detectors 20.1 in the immediate vicinity of the pocket stop 7 is not absolutely necessary. If, however, such a placement is to be provided, the detectors 20.1 are preferably adjustable together with the pocket stop 7 for adaptation to changing leg lengths of the signatures during a job change. For this purpose, in the present embodiment preferably one of the adjusting means 16 forming spindle drives is used.

LIST OF REFERENCE NUMBERS

1

buckle

2

Flat workpiece

2 '

signature

2.1

leading edge of the workpiece 2

3

folding pocket

4

folding pocket

5

folding pocket

6

folding pocket

7

pocket stop

8th

transport roller

9

Transport and folding roller

10

Folding and transport roller

11

Folding and transport roller

12

roller pair

13

Knife shaft pair

14

transport roller

15

Falztaschenrahmen

16

actuating means

17

sensors

17.1

Sound pressure sensor

18

sensors

18.1

Encoder for movements of the pocket stop 7

19

sensors

19.1

Encoder for elastic deformations of the pocket stop 7

20

sensors

20.1

Detector for generating orientation signals

21

control

22

control

23

control

24

control

Claims (3)

1. A device for folding flat workpieces (2) having at least one buckle plate folding device with an adjustable buckle plate stop (7), adjusting means (16) by which at least the orientation of the buckle plate stop (7) can be adjusted, characterized in that the device further comprises a sensor system (17; 18; 19; 20), which generates signals characterizing a sound during the act of the respective leading edge (2.1) of the workpieces (2) impacting the buckle plate stop (7), and a control system (21; 22; 23; 24), which upon evaluation of the signals characterizing the sound controls the adjusting means (16) such that these adjust the buckle plate stop (7) to an orientation at which the leading edge (2.1) comes to a temporary standstill within a delay time which is in accordance with a specified value.
2. A device according to claim 1, characterized by the control system (21; 22; 23; 24) being of such design that it reduces the delay time to a time slot, the span of which is at least virtually equal to zero.
3. A device according to claim 1, characterized in that the sensor system (17) comprises a sound pressure sensor (17.1).

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