. Publication number: B1

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_„. © Publication number: Office europeen des brevets

© EUROPEAN PATENT S P E C I F I C A T I O N

@ Date of filing: 07.01.87

00 CO CO CO CM © Priority: 20.02.86 US 831211 @ Date of publication of application:

02.09.87 Bulletin 87/36

Proprietor: MOLINS MACHINE COMPANY, INC. 111 Woodcrest Road

Cherry Hill New Jersey 08034(US) Inventor: Craemer, Robert H. 110 White Oak Drive

Cherry Hill New Jersey 08034(US)

Representative: Thomson, Roger Bruce et al POLLAK MERCER & TENCH Eastcheap House Central Approach

Letchworth Hertfordshire SG6 3DS(GB)

O Note: Within nine months from the publication of the mention of the grant of the European patent, any person ^ may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition qj shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee

has been paid (Art. 99(1) European patent convention).

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Description

Background Of The Invention

This invention relates generally to printer-slotters for printing and slotting carton blanks which are usually of double-face corrugated paperboard. More particularly, the present invention is directed to a phase register control to maintain registration of operating shaft mounted cylinders during the fitting of a printing die or adjustment of the slotter heads.

In a conventional printer-slotter machine, each operation is performed successively by a module or section which may be opened for the fitting of attachments, cleaning and servicing. When the modules are in the closed position for operation, power is transmitted from a main drive motor in the feed end module by means of intermeshing gears in each module. If the printing module, for exam- ple, is separated from its adjustment modules, the power train gears are exposed and free to rotate.

When servicing the modules, the usual practice is for the operator to separate the modules so that the cylinders are readily accessible. In changing a printing die, for instance, the die is fastened to the print cylinder by staples or special clamps. Be- cause of the length of the die, it is customary to rotate the cylinder to mount the die on the cylinder so that both ends of the die may be secured. Rotation of the cylinder affects the register of that station with respect to the rest of the machine. Similar problems may occur with the slotter cylinders or, if present, the die cutting cylinders, during set-up or adjustment of those machine sections, such that the cylinders will not mesh in register when the modules are reclosed.

To overcome this problem, timing marks have been placed on the cylinder shaft gears. Before the sections are reclosed, the gears are rotated (by hand, crank or otherwise) so that the timing marks are brought or set into proper relative alignment. This alignment must be maintained while the gears are re-engaged and the modules reclosed. If the operator forgets to set the timing prior to closing the machine, the initial sheets will be scrap and the machine will have to be opened again and the timing set correctly by rotating the gears. This is a time-consuming operation because trials must be made and blanks examined to establish that the proper relationship exists between a given cylinder and the cylinders in the remaining sections. The change may or may not be noted by the operator upon visual inspection of the gear timing marks. To restore the proper phase relationship, the sections must be decoupled again and the gear associated with the displaced cylinder shaft must be rotated to bring the timing mark back into alignment. If the

change is not noted by the operator upon visual inspection of the gears, the machine will produce scrap sheets wherein the slots and/or printing are not correctly registered on each blank. An operator, 5 upon noticing this condition must shut down the machine and then rotate the cylinders and gears so as to bring the elements into alignment, the result is a significant loss in production time and material.

Various mechanisms for setting the phase ad- io justment are well known in the industry. One type of mechanism is shown in U.S. Patent 2,677,971. Other mechanisms may comprise a harmonic differential, a worm gear differential or the like. A worm gear differential is described in U.S. Patent 75 3,003,403.

Numerous solutions have been proposed to ensure alignment of the operating elements during separations of the modules. U.S. Patent 2,975,706 for Printer Slotter Machine describes an arrange- 20 ment in which each module is coupled to a splined shaft extending the length of the opened machine.

U.S. Patent 2,866,408 for a Transmission De- vice for Rotary Printing Machines employs an anal- ogous shaft provided with a bevelled gear which 25 may be coupled to each module.

Another arrangement is for a gear locking mechanism as in U.S. Patent 3,611,925 Printer Slotter Module Gear Train Brake.

To eliminate the manual operations described 30 above, a solution has been proposed in U.S. Patent 4,527,788 issued July 9, 1985. In that patent, the machine sections are independently driven so as to eliminate the gear coupling between sections. The phase relationship between the shaft cylinders is 35 then controlled electronically both at set up and during dynamic operation of the machine under normal conditions. The solution proposed in the patent requires a relatively sophisticated but un- reliable and expensive electronic control and in- 40 dividual variable speed drives.

Another known arrangement is found in EP-A- 0096565. This describes an apparatus for sensing the angular position of rotating shafts, generating signals representative of their angular position and 45 producing an error signal if the shafts become out

of phase.

Summary of Invention

50 In accordance with the invention there is provided an apparatus for maintaining phase register among the shafts of the sections of a printer-slotter machine as claimed in claim 1.

Also in accordance with the invention there is 55 provided a method of maintaining phase register among the shafts of the sections of a printer-slotter machine as claimed in claim 5.

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cylinder is provided with means for adjusting the angular position of the cylinder shaft, each shaft includes a compensator motor and an encoder. Each encoder is connected to a digital counter to count the pulses generated by its associated encoder. Each pulse generated represents an incre- ment of angular shaft displacement. Each counter is coupled to a comparator which is used to drive the compensator motor so as to rotate its associated shaft cylinder until the angular displacement of the shaft cylinder relative to the angular position of a reference cylinder in the printer slotter feed section is equal to the desired angular displacement of the shaft cylinder.

Accordingly, the present invention provides a simple, reliable and relatively inexpensive phase register control for a printer slotter which maintains correct register and timing without operator intervention.

The invention also provides an automated printer slotter which maintains correct register and timing without operator intervention.

The automated phase register control may easily be retro-fitted to conventional gear-driven printer slotters.

Brief Description of the Drawings

Figure 1 is a diagrammatic representation of a printer-slotter machine showing the separable track-mounted sections.

Figure 2 is a plan diagram of the conventional gear coupled shaft cylinders as well as the shaft- mounted encoders of the present invention.

Figure 3 is a block diagram of the phase register control of the present invention.

Detailed Description of the Invention

Referring to the drawings, wherein like numer- als indicate like elements, there is shown in Figure 1 a conventional printer-slotter machine designated generally as 10. The machine includes a feeder section 12, printing sections 14 and 16 and slotter- scorer section 18, all sections being mounted on a track 20. A blank 22 is fed through the feeder section 12 to the remaining machine sections 14, 16, 18 wherein the blank is printed, slotted and scored. Each section includes a pair of shaft mounted cylinders designated 12a, b, 14a, b, 16a, b and 18a, b. Each cylinder is mounted for rotation with its associated shaft.

The cylinder shafts are gear coupled from section to section as shown in Figure 2. Feed cylinder 12a is mounted on a shaft which is coupled by differential 24 and gear 26 to drive motor M. Print cylinder 14a is coupled by differential 28 to gear 30. Print cylinder 16a is coupled by differential 32

to gear 34. Cylinder 14a and cylinder 16a carry conventional printing plate elements (not shown). Slotter-scorer cylinder 18a is coupled by differential 36 to gear 38. Cylinder 18a carries the conven- 5 tional slotting-scoring tools (not shown). Differen- tials 24, 28, 32, 36 are conventional harmonic or worm gear differentials or the like, well-known to the artisan. During operation, gears 26, 30, 34 and 38 are in meshing relation wherein the single drive io motor M provides the drive power for all shaft

cylinders.

Each gear is provided with timing mark T in the usual manner. The desired phase relation or relative angular positions among all cylinders can be is set-up in the conventional semi-automatic proce- dure by separating the sections, rotating the gears so that the timing marks T are brought into alignment, closing the sections and then separately actuating each differential so as to rotate the cyl- 20 inder shafts to bring the cylinders to their desired angular positions (while the gears are engaged with the timing marks in alignment).

In the present invention, a shaft encoder is mounted at the end of each cylinder shaft. See 25 Figure 2. Encoder 40 is mounted on the shaft carrying feed cylinder 12a. Encoder 40 serves as a reference encoder as described more fully here- after. Encoder 42 is mounted at the end of the shaft carrying the print cylinder 14a. Encoder 44 is 30 mounted at the end of the shaft carrying the print cylinder 16a. Encoder 46 is mounted at the end of the shaft carrying the slotting-scoring cylinder 18a. All encoders are preferably of the digital incre- mental type, although absolute digital encoders and 35 analog shaft angle sensor-generators may also be employed as will become evident to the artisan from the following disclosure.

As shown in Figure 3, each encoder is elec- trically connected to a digital counter. Encoder 40 40 is connected to counter 48. Encoder 42 is connected to counter 50. Encoder 44 is connected to counter 52. Encoder 46 is connected to counter 54. Each encoder generates a predetermined number of pulses per revolution of its associated shaft. 45 Each counter counts the pulses generated by the associated encoder. Each pulse represents an in- crement of angular shaft displacement. All counters may be of the up/down type so as to indicate clockwise and counter clockwise angular shaft dis- 50 placement. All counters are provided by the soft-

ware programmed in a microprocessor 58.

To set up the desired phase relation among the shaft cylinders, an operator enters the desired angular displacements of the creaser-slotter and print 55 cylinders, 14a, 16a, 18a, at the keyboard 56. See Figure 3. The outputs of the keyboard are designated 0. Each keyboard output 0 represents the desired angular displacement of a cylinder with

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respect to the angular position of reference cylinder 12a. Each output 0 is connected to an adder 60, 62, 64. All adders are provided by the software programmed in microprocessor 58.

Each of the outputs or counts of counters 50, 52 and 54 is designated a in Figure 3. Each of these outputs represent actual angular displacement of a creaser-slotter or printing section shaft. The output of counter 48 is designated /3 in Figure 3. This output represents actual angular displacement of the reference (feeder) section shaft. Each shaft encoder 40, 42, 44, 46 generates one marker pulse per shaft revolution in addition to the other pulses generated by the encoder. Each marker pulse resets the counter associated with the shaft encoder.

The output a of each counter, 50, 52, 54 is added to the corresponding phase signal 0 generated at keyboard 56 by adders 60, 62, 64. The output of each adder is therefore the sum (0 + a), and this sum is compared to the output or count /3 of counter 48 by comparators 66, 68, 70. All comparators are provided by the microprocessor software. The output of each comparator is designated € in Figure 3, and in each case e = 0 - (a + 0). The output € of a comparator represents the dif- ference between (1) the actual angular displacement of shaft cylinder 14a, 16a or 18a relative to the angular position of the reference (feed) cylinder 12a and (2) the desired angular displacement of the cylinders 14a, 16a or 18a with respect to the angular position of the reference (feed) cylinder 12a. Thus, each comparator output e is an error signal, and it is used to drive a differential 28, 32 or 36 so as to rotate the associated shaft cylinder 14a, 16a or 18a until the actual angular displacement of the shaft cylinder relative to the angular position of reference cylinder 12a is made equal to the desired angular displacement 0 of the shaft cylinder with respect to the reference cylinder 12a. Thereafter, phase relation between all cylinders is locked mechanically by the gears and the differentials, which are prevented from further adjustment. During normal operation, the phase relationship among all cylinders can be maintained to an accu- racy of the order of 0.28° of arc (5 mils).

From the foregoing, it can be appreciated that in the present invention none of the machine sections need be decoupled during set up of the shaft cylinders to achieve the desired phase relationship. Thus, set up of the shaft cylinders is achieved electronically and it is unnecessary to bring the gear timing marks into alignment. Moreover, since the shaft cylinders are gear coupled rather than being independently driven, the invention elimi- nates the problem of loss of phase register due to differing acceleration or deceleration rates and varying load characteristics of individual variable

speed drives.

In addition, the invention is suited for easy retrofit to a conventional printer-slotter machine while retaining the single motor drive and gear 5 coupling arrangement of the original machine. Should the phase register control of the present invention fail for any reason, due to microprocessor malfunction or the like, the shaft cylinders may be set up in the desired phase relationship utilising the io differentials 24, 28, 32, 36 and the gear timing marks in accordance with the conventional proce- dure (i.e. full manual backup).

Claims 15

1. Apparatus for maintaining phase register among the shafts of the sections of a printer- slotter machine including a reference shaft (12a, 12b), comprising:

20 gear means (26, 30, 34, 38) for coupling said section shafts (12a, 12b; 14a, 14b etc.) so that said shafts are rotatable in unison,

means (40) for sensing the angular position of said reference shaft and generating a 25 first signal representative thereof,

means (42, 44 or 46) for sensing angular position of another machine section shaft and generating a second signal representative thereof,

30 means (66, 68 or 70) for combining said first and second signals and generating an error signal based thereon, and

means (28, 32 or 36) for separately rotating said machine section shaft in response to 35 said error signal to bring said machine section shaft into the desired angular position with respect to the position of said reference shaft,

characterised by user-operable input means (56) for selecting a desired angular 40 position for said machine section shaft with respect to the angular position of said reference shaft and generating a third signal representative thereof, and by the combining means (66, 68, 70) combining the third signal with the 45 first and second signals for generating the er-

ror signal.

2. Apparatus for maintaining phase register among the shafts of the sections of a printer- 50 slotter machine according to claim 1, characterised in that said user-operable input means comprises a keyboard (56) and in that said means for combining said first, second and third signals includes a programmed micropro- 55 cessor (58) operatively coupled to the keyboard and to said means for sensing angular position of said reference and machine section shafts.

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3. Apparatus for maintaining phase register among the shafts of the sections of a printer- slotter machine according to claim 1 or 2, characterised in that said means for separately rotating said machine section shaft includes a differential (28, 32 or 36) coupling said machine section shaft to a gear associated there- with.

4. Apparatus for maintaining phase register among the shafts of the sections of a printer- slotter machine according to claim 3, characterised in that said means for sensing angular position of said reference and machine section shafts are encoders (40, 42, 44, 46).

5. A method of maintaining phase register among the shafts of the sections of a printer-slotter machine including a reference shaft, comprising:

coupling said shafts mechanically so that said shafts are rotatable in unison,

sensing angular position of said reference shaft and generating a first signal representative thereof,

sensing angular position of another machine section shaft and generating a second signal representative thereof,

generating a third signal representative of desired angular position of said machine section shaft with respect to the angular position of said reference shaft,

combining said first, second and third signals and generating an error signal based thereon, and

separately rotating said machine section shaft in response to said error signal to bring said machine section shaft into the desired angular position with respect to the position of said reference shaft.

6. A method of maintaining phase register among the shafts of the sections of a printer-slotter machine according to claim 5, characterised in that said step of combining said first, second and third signals includes summing said second and third signals and comparing the sum with said first signal.

Patentanspruche

1. Vorrichtung zum Aufrechterhalten des Phasen- registers zwischen den Wellen der Abschnitte einer Druck-Schlitzmaschine mit einer Bezugs- welle (12a, 12b), welche aufweist:

ein Getriebe (26, 30, 34, 38) zum Kuppeln der Maschinenabschnitts-Wellen (12a, 12b; 14a, 14b etc.), so da/S die Wellen gemeinsam

drehbar sind,

Signalmittel (40) zum Abfuhlen der Winkel- stellung der Bezugswelle und zum Erzeugen eines entsprechenden ersten Signals,

5 Signalmittel (42, 44 oder 46) zum Abfuhlen der Winkelstellung einer anderen Maschinen- Abschnittswelle und zum Erzeugen eines entsprechenden zweiten Signals,

Verknupfungsmittel (66, 68 oder 70) zum io Verknupfen des ersten und das zweiten Signa- le und zum Erzeugen eines hierauf basieren- den Fehlersignals, und

Drehmittel (28, 32 oder 36) zum getrenn-

ten Drehen der betreffenden

is Maschinenabschnitts-Welle in Abhangigkeit von dem Fehlersignal, urn diese Maschinenab- schnittswelle in die Sollwinkelstellung bezuglich der Stellung der Bezugswelle zu bringen,

dadurch gekennzeichnet, da/S durch eine 20 Bedienungsperson betatigbare Eingabemittel (56) zum Auswahlen einer Sollwinkelstellung fur die besagte Maschinenabschnitts-Welle bezuglich der Winkelstellung der Bezugswelle und zum Erzeugen eines entsprechenden drit- 25 ten Signals vorgesehen sind und da/S die Ver- knupfungsmittel (66, 68, 70) das dritte Signal mit dem ersten und zweiten Signal verknupfen, urn das Fehlersignal zu erzeugen.

30 2. Vorrichtung zum Aufrechterhalten des Phasen- registers zwischen den Wellen der Abschnitte einer Druck-Schlitzmaschine nach Anspruch 1, dadurch gekennzeichnet, da/S die durch eine Bedienungsperson betatigbaren Eingabemittel 35 ein Tastenfeld (56) aufweisen und da/S die Ver- knupfungsmittel zum Verknupfen des ersten, zweiten und dritten Signales einen program- mierten Mikroprozessor (58) umfassen, der mit dem Tastenfeld und mit den Signalmitteln zum 40 Abfuhlen der Winkelposition der Bezugswelle und der Maschinenabschnitts-Welle funktions- ma/Sig verbunden ist.

3. Vorrichtung zum Aufrechterhalten des Phasen- 45 registers zwischen den Wellen der Abschnitte einer Druck-Schlitzmaschine nach Anspruch 1 oder 2, dadurch gekennzeichnet, da/S die Dreh- mittel zum getrennten Drehen der Maschinenabschnitts-Welle ein Differential (28,

50 32 oder 36) umfassen, das die

Maschinenabschnitts-Welle mit einem zuge- ordneten Zahnrad verbindet.

4. Vorrichtung zum Aufrechterhalten des Phasen- 55 registers zwischen den Wellen der Abschnitte einer Druck-Schlitzmaschine nach Anspruch 3, dadurch gekennzeichnet, da/S die Signalmittel zum Abfuhlen der Winkelstellung mit der

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Bezugs- und Maschinenabschnitts-Welle aus Kodierern (40, 42, 44, 46) bestehen.

5. Verfahren zum Aufrechterhalten des Phasenre- gisters zwischen den Wellen der Abschnitte einer Druck-Schlitzmaschine mit einer Bezugs- welle, bei dem:

die Wellen mechanisch gekuppelt werden, so da/S die Wellen gemeinsam drehbar sind,

die Winkelstellung der Bezugswelle abgefuhlt und ein entsprechendes erstes Signal erzeugt wird,

die Winkelstellung einer anderen Maschinenabschnitts-Welle abgefuhlt und ein entsprechendes zweites Signal erzeugt wird,

ein drittes Signal erzeugt wird, das die

Sollwinkelstellung der besagten

Maschinenabschnitts-Welle bezuglich der Win- kelstellung der Bezugswelle darstellt,

das erste, zweite und dritte Signal ver- knupft und auf dieser Basis ein Fehlersignal erzeugt wird, und

die besagte Maschinenabschnitts-Welle in Abhangigkeit von dem Fehlersignal getrennt gedreht wird, urn die Maschinenabschnittswelle in die Sollwinkelstellung bezuglich der Stellung der Bezugswelle zu bringen.

6. Verfahren zum Aufrechterhalten des Phasenre- gisters zwischen den Wellen der Abschnitte einer Druck-Schlitzmaschine nach Anspruch 5, dadurch gekennzeichnet, da/S das Verknupfen des ersten, zweiten und dritten Signals eine Addition des zweiten und dritten Signals und ein Vergleich der Summe mit dem ersten Si- gnal umfa/St.

Revendicatlons

1. Dispositif pour maintenir un reperage de phase parmi les arbres des sections d'une machine d'impression et de rainurage comportant un arbre de reference (12a, 12b), comprenant :

- un systeme de pignons (26, 30, 34, 38) pour coupler lesdites sections d'arbres (12a, 12b ; 14a, 14b, etc) de maniere que lesdits arbres tournent a I'unisson ; - des moyens (40) pour detecter la posi-

tion angulaire dudit arbre de reference et generer un premier signal representatif de celle-ci ;

- des moyens (42, 44 ou 46) pour detecter la position angulaire d'un arbre d'une autre section de la machine et pour generer un second signal representatif de celle-ci - des moyens (66, 68 ou 70) pour combiner lesdits premier et second signaux et

engendrer un signal d'erreur base sur ceux-ci ;

- des moyens (28, 32 ou 36) pour faire tourner de fagon separee ledit arbre de 5 section de la machine en reponse au signal d'erreur afin d'amener ledit arbre de section de la machine dans la position angulaire desiree par rapport a la position dudit arbre de reference,

io caracterise par des moyens d'entree actionnable par I'utilisateur (56) pour selectionner une position angulaire desiree pour ledit arbre de section de la machine par rapport a la position angulaire dudit arbre de reference et is pour generer un troisieme signal representatif de cette position et, par les moyens de combi- naison (66, 68, 70), combiner le troisieme signal avec les premier et second signaux pour generer le signal d'erreur.

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2. Dispositif pour maintenir un reperage de phase parmi les arbres des sections d'une machine a imprimer et a rainurer selon la revendication 1 , caracterise en ce que les moyens d'entree 25 actionnable par I'operateur comprennent un clavier (56) et en ce que lesdits moyens pour combiner lesdits premier, second et troisieme signaux comprennent un microprocesseur pro- gramme (58) couple, de fagon operationnelle, 30 au clavier et auxdits moyens de detection de la position angulaire des arbres de reference et des sections de la machine.

3. Dispositif pour maintenir un reperage de phase 35 parmi les arbres des sections d'une machine a imprimer et a rainurer selon la revendication 1 ou 2, caracterise en ce que lesdits moyens pour faire tourner de fagon separee ledit arbre de section de la machine comprennent un 40 differentiel (28, 32 ou 36) couplant ledit arbre de section de la machine a un pignon qui lui est associe.

4. Dispositif pour maintenir un reperage de phase 45 parmi les arbres des sections d'une machine a imprimer et a rainurer, caracterise en ce que lesdits moyens pour detecter la position angulaire desdits arbres de reference et de sections de machine sont des codeurs (40, 42, 44, 46). 50

5. Procede pour maintenir un reperage de phase parmi les arbres des sections d'une machine a imprimer et a rainurer comportant un arbre de reference, qui consiste a :

55 - coupler mecaniquement lesdits arbres de maniere que lesdits arbres tournent a I'unisson ;

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de reference et generer un premier signal representatif de celle-ci ;

- detecter la position angulaire d'un autre arbre de section de la machine et generer un second signal representatif de 5 celle-ci ;

- generer un troisieme signal representatif de la position angulaire desiree dudit arbre de section de la machine par rapport a la position angulaire dudit arbre de 10 reference ;

- combiner lesdits premier, second et troisieme signaux et generer un signal d'erreur base sur ces signaux et,

- faire tourner de fagon separee ledit arbre is de section de la machine en reponse audit signal d'erreur afin d'amener ledit arbre de section de machine dans la position angulaire desiree par rapport a la position dudit arbre de reference. 20 Procede pour maintenir un reperage de phase parmi les arbres des sections d'une machine a imprimer et a rainurer selon la revendication 5, caracterise en ce que ladite etape de combi- 25 naison desdits premier, second et troisieme signaux consiste a additionner lesdits second et troisieme signaux et a comparer la somme audit premier signal.

30 35 40 45 50 55

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' 6 b / & b