GB1579976A - Plate cylinder for rotary printing machine - Google Patents

Abstract

The attachment device arranged in the gap (2) of a forme cylinder (1) consists of a longitudinal stand which can be installed and removed, without demounting the cylinder (1), by subdivision into a lower and an upper part (5a, 5c). The longitudinal stand bears spindles (6, 6') with attachment strips (7) which are attached adjustably by setting screws (10) via arms (11) counter to the force of spring pressure bolts (16), and also bears register pins mounted adjustably in blocks. As a result, the alignment of printing plates (3, 4) in the circumferential and lateral direction can be undertaken conveniently and the attachment operation can easily be observed. <IMAGE>

Description

(54) PLATE CYLINDER FOR ROTARY PRINTING MACHINES (71) We, ALBERT-FRANKENTHAL AK TIENGESELLSCHAFT, a German body Corporate of Johann-Klein-Strasse 1, D6710 Frankenthal/Pfalz, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- The invention relates to plate cylinders, for rotary printing machines, preferably for offset printing, having a device for clamping flexible printing plates on the cylinder and is applicable where the plates have acuteangled rearwardly cranked ends engageable with clamping bars pivotally arranged in grooves parallel to the axis of the cylinder.

In known devices of this type the attachment of the plate end that determines the location of the plate in the peripheral direction, takes place on the acute angled jaw of the plate cylinder itself, where its groove aperture opens onto the plate cylinder surface.

The clamping of the plate takes place at the other plate end. The actuating members requisite for this lie for the most part On a cylinder front wall, so that observation by the operator of the effect of his actuation of the clamping means on the axially inwardly arranged plates is virtually impossible.Fur- thermore adjustment of the suspension pins determining the lateral register is either mainly not possible or only with complicated means and in hardly reliable stable manner.

According to the present invention there is provided a plate cylinder, for a rotary printing machine, having a device for clamping a flexible printing plate upon the cylinder, comprising a longitudinal member centrally disposed in a groove in the cylinder and clamping means operable to clamp an end of a plate upon a planar abutment surface of the longitudinal member.

Second clamping means may be provided to cooperate oppositely with a further, planar abutment surface of the longitudinal member to secure and locate a different plate end relative to the cylinder. Then the first clamping means may serve to clamp the plate end directly onto the longitudinal member and the second clamping means may serve to secure the plate end relative to, but spaced from, the longitudinal member, which may then have biassing means to urge the spaced plate end against the corresponding clamping means.

In preferred embodiments of the invention for clamping printing plates having acutely angled ends, the abutment surfaces are correspondingly inclined.

In embodiments of the invention the alignment of the plate in the peripheral and lateral direction and the clamping as such may be carried out on a stable longitudinal member.

Thus register pins can not only be firmly mounted in it, but also can be adjustable, by simple means, as may be required to take account of different paper tension of different paper types arising from moistening, wherein the outer zones are more affected than the inner zones.

Actuation of clamping members may be by way of set screws, provided in the longitudinal member and accessible from above, thus permitting operation in the range of view of the plate. With several plates in the peripheral direction, separate set screws for each of the oppositely lying plate ends permit clamping and unclamping of an individual plate without affecting another plate. That also facilitates handling of the plates.

Preferably the longitudinal member and operating elements combined therein, can be inserted in and removed from the groove without disassembly of the cylinder.

One embodiment of the invention will now be described by way of example only and with reference to the accompanying drawing in which: Figure 1 shows a sector of a plate cylinder with a clamping device and is a cross-section in the plane of the register pins.

Figure 2 is a similar cross-section in the plane of a clamping screw.

Figure 3 is a plan view.

Only the sector of the plate cylinder 1 is indicated in which is the groove 2, parallel to the cylinder axis, for reception of the clamping device for the ends of flexible plates 3 and 4.

This clamping device consists of a longitud inal member 5 in the longitudinal central plane of the groove; the member is divided into a lower part 5a and upper part Sc, so that the whole device is insertable and removable without disassembly of the cylinder. Both parts 5a and Sc are fixedly screwed to the base of the groove by mutual screws 12. They also support rotatable spindles 6 and 61 with the clamping members or bars 7. On both sides of a head part 5b of the upper part Sc are arranged desk blocks 13 each inclined on one side to form a planar surface 9. These each carry a register pin 8, which fits in a corresponding slot of the acute-angled cranked ends of the printing plates 3, 4 attached over the cjamping bars 7.

The desk blocks 13 are additionally adjustable parallel to the axis after release of the clamping screws 14. They are likewise guided in guides 15 as well as the remaining desk parts, which extend over the remaining breadth of the plate cylinder. The left inclined surface 9 provides the exact location in the peripheral direction for the acute-angled cranked end of the plate 3, whilst the acuteangled cranked end of the plate 4 approaches only as close to the right inclined surface 9 as the clamping permits. There thus remains here a gap shown in Figures 1 and 2 in which an indicated leaf spring is secured so that the cranked plate end does not rise.

As can be seen from Figures 2 and 3, notches are distributed in the longitudinal direction of the cylinder in the head part 5b of the longitudinal frame, in which set screws 10 are accessible, which are screwed into the upper part 5c, and which press on the arm 11 of the spindle 6, whilst other screws not shown press on the arm of spindle 61 and accordingly clamp the end of the plate 4 by way of its clamping bar 7. If several printing plates are distributed along the periphery it is clear that each plate lies separately without affecting the others and can be separately clamped or removed. On the side of each arm 11 opposite to the set screws 10 is a spring pressure bolt 16 for resetting the arm as the set screws 10 are unscrewed.

WHAT WE CLAIM IS 1. A plate cylinder, for a rotary printing machine, having a device for clamping a flexible printing plate upon the cylinder, comprising a longitudinal member centrally disposed in a groove in the cylinder and clamping means operable to clamp an end of a plate upon a planar abutment surface of the longitudinal member.

2. A plate cylinder as claimed in claim 1, wherein second clamping means is cooperable oppositely with a further abutment surface of the longitudinal member to secure and locate a different plate end relative to the cylinder.

3. A plate cylinder as claimed in claim 1 or 2 wherein the second clamping means serves to secure the different plate end relative to but spaced from the longitudinal member.

4. A plate cylinder as claimed in claim 4, the longitudinal member having biassing means to urge the spaced plate end against the corresponding clamping means.

5. A plate cylinder as claimed in any preceding claim, wherein the or each planar abutment surface is acutely inclined relative to the cylinder surface adjacent the groove.

6. A plate cylinder as claimed in any preceding claim, wherein the longitudinal member is insertable in and removable from the groove without disassembly of the cylinder.

7. A plate cylinder as claimed in claim 6, wherein the longitudinal member is divisible into portions for insertion into or removal from the groove.

8. A plate cylinder as claimed in any preceding claim, wherein actuation of the or each clamping means is effected by means accessible from above the longitudinal member.

9. A plate cylinder as claimed in any one of the preceding claims, wherein the or each clamping means comprises a bar carried by a spindle rotatably mounted at the lower part of the longitudinal member.

10. A plate cylinder as claimed in claim 9, as appendent to claim 8, wherein the means accessible from above the longitudinal member comprise screws extending through the member to rotate the or each spindle.

11. A plate cylinder as claimed in any preceding claim, wherein the longitudinal member carries register pins for location of the plates axially relative to the cylinder.

12. A plate cylinder as claimed in claim 11, wherein the register pins are laterally displaceable relative to the cylinder and securable at desired displacements.

13. A plate cylinder as claimed in claim 12, wherein the pins extend from blocks displaceable laterally in guides on the cylinder.

14. A plate cylinder, for rotary printing machines, having a device for clamping flexible printing plates on the cylinder substantially as described herein with reference to and as shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (14)

**WARNING** start of CLMS field may overlap end of DESC **. inal member 5 in the longitudinal central plane of the groove; the member is divided into a lower part 5a and upper part Sc, so that the whole device is insertable and removable without disassembly of the cylinder. Both parts 5a and Sc are fixedly screwed to the base of the groove by mutual screws 12. They also support rotatable spindles 6 and 61 with the clamping members or bars 7. On both sides of a head part 5b of the upper part Sc are arranged desk blocks 13 each inclined on one side to form a planar surface 9. These each carry a register pin 8, which fits in a corresponding slot of the acute-angled cranked ends of the printing plates 3, 4 attached over the cjamping bars 7. The desk blocks 13 are additionally adjustable parallel to the axis after release of the clamping screws 14. They are likewise guided in guides 15 as well as the remaining desk parts, which extend over the remaining breadth of the plate cylinder. The left inclined surface 9 provides the exact location in the peripheral direction for the acute-angled cranked end of the plate 3, whilst the acuteangled cranked end of the plate 4 approaches only as close to the right inclined surface 9 as the clamping permits. There thus remains here a gap shown in Figures 1 and 2 in which an indicated leaf spring is secured so that the cranked plate end does not rise. As can be seen from Figures 2 and 3, notches are distributed in the longitudinal direction of the cylinder in the head part 5b of the longitudinal frame, in which set screws 10 are accessible, which are screwed into the upper part 5c, and which press on the arm 11 of the spindle 6, whilst other screws not shown press on the arm of spindle 61 and accordingly clamp the end of the plate 4 by way of its clamping bar 7. If several printing plates are distributed along the periphery it is clear that each plate lies separately without affecting the others and can be separately clamped or removed. On the side of each arm 11 opposite to the set screws 10 is a spring pressure bolt 16 for resetting the arm as the set screws 10 are unscrewed. WHAT WE CLAIM IS

1. A plate cylinder, for a rotary printing machine, having a device for clamping a flexible printing plate upon the cylinder, comprising a longitudinal member centrally disposed in a groove in the cylinder and clamping means operable to clamp an end of a plate upon a planar abutment surface of the longitudinal member.

2. A plate cylinder as claimed in claim 1, wherein second clamping means is cooperable oppositely with a further abutment surface of the longitudinal member to secure and locate a different plate end relative to the cylinder.

3. A plate cylinder as claimed in claim 1 or 2 wherein the second clamping means serves to secure the different plate end relative to but spaced from the longitudinal member.

4. A plate cylinder as claimed in claim 4, the longitudinal member having biassing means to urge the spaced plate end against the corresponding clamping means.

5. A plate cylinder as claimed in any preceding claim, wherein the or each planar abutment surface is acutely inclined relative to the cylinder surface adjacent the groove.

6. A plate cylinder as claimed in any preceding claim, wherein the longitudinal member is insertable in and removable from the groove without disassembly of the cylinder.

7. A plate cylinder as claimed in claim 6, wherein the longitudinal member is divisible into portions for insertion into or removal from the groove.

8. A plate cylinder as claimed in any preceding claim, wherein actuation of the or each clamping means is effected by means accessible from above the longitudinal member.

9. A plate cylinder as claimed in any one of the preceding claims, wherein the or each clamping means comprises a bar carried by a spindle rotatably mounted at the lower part of the longitudinal member.

10. A plate cylinder as claimed in claim 9, as appendent to claim 8, wherein the means accessible from above the longitudinal member comprise screws extending through the member to rotate the or each spindle.

11. A plate cylinder as claimed in any preceding claim, wherein the longitudinal member carries register pins for location of the plates axially relative to the cylinder.

12. A plate cylinder as claimed in claim 11, wherein the register pins are laterally displaceable relative to the cylinder and securable at desired displacements.

13. A plate cylinder as claimed in claim 12, wherein the pins extend from blocks displaceable laterally in guides on the cylinder.

14. A plate cylinder, for rotary printing machines, having a device for clamping flexible printing plates on the cylinder substantially as described herein with reference to and as shown in the accompanying drawings.