EP1090752B1 - Bearing for a cylindrical screen in a rotary screen printing press - Google Patents

Abstract

The bearing is for the cylindrical vat which is contained on both sides by means of stencil rings (9) in a turnbuckle (8) mounted in an intermediate ring. (2) Each intermediate ring is flat and is spring-mounted in a side-plate (1) of the printer. The intermediate ring can swivel in relation to the side-plate and can move in an axial direction. Of two flat concentric rings the inner ring is connected to the outer ring by two diametrically opposite bridge pieces. The outer ring is joined to a holder enclosing the ring by two diametrically opposite bridge pieces

Description

The present invention relates to a bearing for the round screen in rotary screen printing, wherein the screen is received in cylindrical form on both sides via template rings each in a turnbuckle, which in turn is rotatably mounted in an intermediate ring.

Printing forms for rotary screen printing are manufactured from so-called Screeny screen printing plates, which are mounted as cylinders in the printing unit. This material consists of fine-meshed stabilized steel mesh and may only be subjected to tension (axial load of the round screen). A uniform as possible screen tension at a standstill is desirable, because during the printing process, a different torsional moment is additionally applied by the inner doctor.

Locally greatly different straining stresses cause a wave formation on the screen circumference.

The inherent stability of the screen is ensured by the cylindrical shape.

• Die Konstruktion des Spannschlosses mit der üblichen U-förmigen Ausnahme verursacht bei axialer Belastung ein Kippen des Lagers.
• Die Geräte zur Herstellung der Siebe weisen Abweichungen auf oder können mit Klebstoffresten verschmutzt sein, so dass die äusseren Schablonenringe nicht genau zueinander fluchten.
• Unter der axialen Spannung, die für das Sieb notwendig ist, werden die Seitenplatten mit den Lagerstellen verformt, so dass die Achsrichtungen zueinander einen Winkel bilden.
• Allgemeine Toleranzen im Druckwerk können zu verschiedenen Fehlern führen, z.B. Koaxialabweichung der Lagerpositionen zueinander etc.

During insertion and during the printing process, the screen is loaded differently for several reasons:

• The design of the turnbuckle with the usual U-shaped exception caused by axial load tilting of the bearing.
• The devices for producing the screens have deviations or may be contaminated with adhesive residues, so that the outer stencil rings are not exactly aligned with each other.
• Under the axial tension necessary for the screen, the side plates are deformed with the bearings so that the axial directions form an angle with each other.
• General tolerances in the printing unit can lead to various errors, eg coaxial deviation of the bearing positions, etc.

Experience has shown that the pivoting movement on the screen sides to compensate for all causes up to max. Should be 0.5 °. If no compensation can take place, wave formations are observed on the printing screen. These shorten the sieve life and lead to early sieve cases and to quality losses in the pressure.

It should also be mentioned that the screen can transmit no moments, so that a balance without restoring moment must be virtually powerless.

Object of the present invention is to find a Sieblagerung, which can compensate for all influences for uneven wire tension under axial load.

The proven turnbuckle with U-shaped receptacle should be able to be retained. The storage should be as flat as possible and can be integrated on both sides in the side plates.

Although a "simple" spherical bearing could create a balance, but requires a complex structure for axial movements. For the proper functioning a larger wrap is necessary, otherwise the ball acts like a wedge. Critical is the size and speed, if designed as a spherical plain bearing.

Similar disadvantages has a purely gimbal bearing

In the document AT 355 054 a stencil receiver for a circular stencil in a rotary stencil printing machine is disclosed. The template is mounted in cylindrical form on stencil end pieces, each having a neck. The stencil end pieces are each stored in a template receptacle in two sliders, which are movable in V-shaped diverging spars. The two sliders enclose the neck of the stencil tail by means of fixed, axially parallel rollers, so that the template is rotatably mounted in the template receptacle. Furthermore, the stencil tail carries a repeat wheel, which engages in a drive pinion. The Rapportrad is mounted axially, with this axial bearing is supported against the sliders. The spars are axially movable along guide columns.

The object is achieved according to the invention in a rotary filter of the type defined by the features of the characterizing part of claim 1.

This solution essentially includes a flat intermediate ring, which is held in the side cheek so resilient that in addition to a pivoting with respect to the cheek, a shift in the axial direction is possible.

Figur 1

eine perspektivische Ansicht auf die Innenseite einer Seitenwange eines Siebdruckwerkes mit in der Wange montierten erfindungsgemässem Lager für den Siebdruckzylinder,

Figur 2

einen Vertikalschnitt, rein schematisch, entlang der Linie II-II von Fig. 1;

Figur 3

das eine Ende eines auf den Schablonenring aufgesetzten Siebdruckzylinders;

Figur 4

einen Vertikalschnitt durch die Siebdruckzylinderachse im Bereich von Spannschloss und Zwischenring;

Figur 5

rein schematisch eine zum Einsatz in eine Druckwerkwange vorgesehene Platte mit integriertem Zwischenring (aus zwei mit federnden Stegen miteinander verbundenen konzentrischen Ringen) als Variante des Lagers, und

Fig. 6

eine weitere Variante des erfindungsgemässen Lagers, insbesondere den Zwischenring bestehend aus einem inneren Basisring mit in dessen Ebene radial nach aussen abstehenden Federzungen.

Particular embodiments of the invention are defined in the dependent claims. The invention will be explained below with reference to exemplary embodiments illustrated in the drawings. It shows:

FIG. 1

a perspective view of the inside of a side wall of a screen printing with mounted in the cheek inventive bearing for the screen printing cylinder,

FIG. 2

a vertical section, purely schematically, along the line II-II of Fig. 1;

FIG. 3

one end of a screen printing cylinder mounted on the stencil ring;

FIG. 4

a vertical section through the screen cylinder axis in the range of turnbuckle and intermediate ring;

FIG. 5

purely schematically provided for use in a printing mechanism cheek plate with integrated intermediate ring (of two interconnected with resilient webs concentric rings) as a variant of the bearing, and

Fig. 6

a further variant of the inventive bearing, in particular the intermediate ring consisting of an inner base ring with in its plane radially outwardly projecting spring tongues.

FIGS. 1 to 4 show a first embodiment of a bearing according to the invention in a side wall 1 of a screen printing unit. In this case, an intermediate ring 2 is provided for rotatably receiving the conventional turnbuckle 8, wherein the screen cylinder carrying the screen cylinder 9 is inserted into the U-shaped receptacle of the turnbuckle 8.

The intermediate ring 2 is mounted by means of its four mutually offset by 90 ° cylindrical pins 3. The pins 3 are held by two flat springs 4, 5 and centered towards the center. A third spring 13 on the back of the cheek 1 holds the intermediate ring 2 in the dead state (balance of power). For the positioning of the pins 3 each two spaced apart from the cheek 1 projecting cylindrical pins 6, 7 are provided.

Thanks to this storage, the screen-printing cylinder can assume any position resulting in operation (it can pivot under load with respect to the cheek 1 resiliently and also move in the axial direction against the action of the springs).

The deflection depth under axial load is determined by the flat springs. It is advantageous if one side has stronger springs, so that the screen printing cylinder shifts imperceptibly when load changes.

Fig. 2 shows in particular the arrangement or effect of acting on the cylinder pins 3 springs 4, 5 and 13th

Fig. 4 shows the arrangement of the turnbuckle 8, which is received on thin ring bearing 14 in the intermediate ring 2.

Fig. 5 shows a purely schematic of a variant of an inventive storage. In a plate 15, two concentric rings 16, 17, each with two resilient connecting webs 18, 19 and 20, 21 incorporated. The webs are each offset by 180 ° to each other (the position of the inner webs 18, 19 is offset from the outer webs 20, 21 by 90 °).

This flexible (spring-elastic) bearing can in particular compensate for run-out errors (wobble movements of the axle) and allows for pivoting movements and slight axial displacements.

Finally, FIG. 6 shows a further variant of a resilient bearing for the intermediate ring. It consists of an inner base ring 22 and a plurality in the plane radially outwardly projecting spring tongues 23rd

In the base ring 22 of the intermediate ring is used, while the outer ends of the spring tongues are held laterally in the cheek. This particularly simple embodiment is able to meet the same requirements with regard to pivotability and easier axial displacement as the bearings described above.

Claims (7)

1. Bearing for the cylindrical screen of rotary screen printing presses, the bearing including turnbuckles for receiving the cylindrical screen in cylindrical shape on both sides by means of stencil rings in a respective one of the turnbuckles, which is received in a side flange of a printing unit,
   characterized in
   that the turnbuckle is supported in an intermediate ring in the shape of a flat component so as to be rotatable and resilient in such a way that, when subject to loading, the circular screen has a capacity to pivot in a spring-elastic way relative to the side flange and to be displaced in axial direction, at least within predetermined limitations.
2. Bearing according to claim 1,
   characterized in
   that the bearing function is achieved by two flat concentric rings, the inner one of which is connected to the outer one by two webs that are diametrically opposite each other, whereas the outer ring is likewise connected to a support surrounding the ring also by means of two webs that are diametrically opposite each other and are staggered relative to the inner connecting webs by 90°.
3. Bearing according to claim 2,
   characterized in
   that all parts of the intermediate ring bearing are integrated in a plate.
4. Bearing according to claim 2,
   characterized in
   that the plate is a steel plate.
5. Bearing according to claim 1,
   characterized in
   that the intermediate ring is equipped with four pins that are staggered relative to each other by 90° and project in the radial direction, the four pins being held at the associated side flange in such a way that the intermediate ring cannot rotate about its axis, but can be pivoted slightly in the axial direction and in relation to the plate against the force of retaining springs.
6. Bearing according to claim 5,
   characterized in
   that each of the pins of the intermediate ring is supported between two guide bolts on the side flange and that leaf springs act on the pins from the front and from behind in such a way that the intermediate ring is kept in an unloaded state irrespective of any axial loading.
7. Bearing according to claim 1,
   characterized in
   that each intermediate ring is held in a flat ring-shaped spring element that is mounted so as to be stationary in the side flange, the spring element being formed by a base ring and a plurality of spring tongues that project in the radial direction in the plane of the base ring, the intermediate ring being firmly supported on the base ring and the spring tongues being supported exclusively at their outer ends.

Images