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DE-102024132648-A1 - Plate cylinder with clamping device and front opening drive and a method for operating a printing press

DE102024132648A1DE 102024132648 A1DE102024132648 A1DE 102024132648A1DE-102024132648-A1

Abstract

The invention relates to a plate cylinder with a cylinder channel in which a clamping device is arranged, the clamping device having a clamping means that is movable with respect to a clamping direction by means of a clamping drive, wherein the clamping device has a rear holding device for holding a trailing end of a lift, which is movable together with the clamping means, and wherein the clamping device has a front clamping device for clamping a leading end of the lift, which has a fixed counter-pressing surface that forms a front clamping gap with a movable pressing surface, and wherein the front clamping device has a closing means comprising a spring element, and wherein a spring force of the spring element counteracts the creation of a gap between the pressing surface and the counter-pressing surface, and wherein the closing means is designed as a toggle lever mechanism or as a leaf spring, and wherein the front clamping device has a front opening drive for opening the front clamping gap, and wherein the front clamping device has a clamping drive for closing the front clamping gap, as well as a method for operating a printing press.

Inventors

  • Bodo Zirnstein
  • Heiko Zitzmann

Assignees

  • KOENIG & BAUER AG

Dates

Publication Date
20260513
Application Date
20241108

Claims (14)

  1. Plate cylinder (32) with at least one cylinder channel (39) in which a clamping device (11) for clamping at least one plate-shaped elevator (13) is arranged, wherein the clamping device (11) has at least one clamping means (12) which is movably arranged with respect to a clamping direction (S) by means of a clamping drive (14), and wherein the clamping device (11) has at least one rear holding device (16) for holding a trailing end (18) of the at least one elevator (13), which is movably arranged together with the clamping means (12) with respect to the clamping direction (S), and wherein the clamping device (11) has at least one front clamping device (17) for clamping a leading end (19) of the at least one elevator (13), and wherein the front clamping device (17) has a front fixed counter-pressure surface (22) which forms a front clamping gap (23) with at least one movable front pressure surface (21), and wherein the front clamping device (17) has at least one a closing means (24) comprising a spring element (26) and wherein a spring force of the spring element (26) of the at least one closing means (24) counteracts the creation and/or increase of a distance (27) of the at least one front pressing surface (21) from the front counter-pressing surface (22) and wherein the at least one closing means (24) is designed as a toggle lever mechanism (24) with at least one spring (26) forcing the toggle lever mechanism (24) into its extended position or as at least one leaf spring (24; 26) and wherein the front clamping device (17) has at least one front opening drive (28) which is arranged to act on the at least one closing means (24) to open the front clamping gap (23), characterized in that the front clamping device (17) has at least one front clamping drive (29) which is arranged to act on the at least one closing means (24) to close the front clamping gap (23).
  2. Plate cylinders Claim 1 , characterized in that the at least one closing means (24) is designed as a spring assembly (24) consisting of several leaf springs (26).
  3. Plate cylinders Claim 1 or 2 , characterized in that the front fixed counter-pressure surface (22) is arranged further outwards in a radial direction (R) than the at least one movable front pressure surface (21).
  4. Plate cylinders Claim 1 or 2 or 3 , characterized in that the front opening drive (28) is designed as a pneumatic drive (28) and/or as a pressurised hose (28).
  5. Plate cylinders Claim 1 or 2 or 3 or 4 , characterized in that the front clamping drive (29) is designed as a pneumatic drive (29) and/or as a pressurised hose (29).
  6. Plate cylinders Claim 1 or 2 or 3 or 4 or 5 , characterized in that the clamping drive (14) is designed as a pneumatic drive (14) and/or as a pressurised hose (14).
  7. Plate cylinders Claim 1 or 2 or 3 or 4 or 5 or 6 , characterized in that the front clamping drive (29) and the clamping drive (14) are connected and/or connectable to each other via at least one pneumatic line (43).
  8. Plate cylinders Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 , characterized in that the front clamping drive (29) and the clamping drive (14) are connected and/or connectable to each other within the plate cylinder (32) via at least one pneumatic line (43).
  9. Plate cylinders Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 , characterized in that the plate cylinder (32) has at least one pressure reducer (47) which is arranged along a pneumatic line system (43) between a rotary feedthrough (46) and the front clamping drive (29).
  10. Plate cylinders Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 , characterized in that the rear holding device (16) is designed as a clamping device (16) for clamping the trailing end (18) of the at least one elevator (13).
  11. Method for operating a printing press, wherein the printing press has at least one printing unit (05; 06) which has at least one plate cylinder (32) according to Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 exhibits.
  12. Procedure according to Claim 11 , characterized in that a clamping force exerted on the trailing end (18) of an elevator (13) resting on the plate cylinder (32) by means of the clamping drive (14) is increased and simultaneously or prior to this, a clamping force is exerted by means of the closing means by using the front clamping drive (29). (24) the clamping force exerted on the leading end (19) of the lift (13) is increased.
  13. Procedure according to Claim 11 or 12 , characterized in that during a rotational movement of the plate cylinder (32) a clamping force exerted on the trailing end (18) of an elevator (13) resting on the plate cylinder (32) by means of the clamping drive (14) is increased and simultaneously or prior to this, a clamping force exerted on the leading end (19) of the elevator (13) by means of the closing means (24) is increased by means of the front clamping drive (29).
  14. Procedure according to Claim 11 or 12 or 13 , characterized in that , to place an elevator (13) onto the plate cylinder (32), the leading end (19) of an elevator (13) is first clamped by means of the front clamping device (17) in a front clamping operation, and that in a displacement operation, the at least one clamping means (12) is initially moved in the clamping direction (S) without the trailing end (18) of the elevator (13), and that during the displacement operation, a first auxiliary force is exerted on the closing means (24) by means of the front opening drive (28), and that subsequently, in at least one positioning operation, the trailing end (18) of the elevator (13) and the clamping means (12) are positioned relative to each other, and that subsequently, in a fixing operation, the trailing end (18) of the elevator (13) is fixed to the clamping means (12) by means of the rear holding device (16), and that subsequently, in a clamping operation, the clamping means (12) is moved in the clamping direction (S) to clamp the elevator (13) to clamp and that a printing process is then carried out, during which the substrate (02) is printed using the plate cylinder (32) by means of the printing machine and that during the printing process no force is exerted on the closing means (24) by means of the front opening drive (28) or a second auxiliary force is exerted on the closing means (24) which is less than the first auxiliary force.

Description

The invention relates to a plate cylinder with a clamping device according to the preamble of claim 1 and to a method for operating a printing press. When printing on absorbent substrates, the substrate expands and contracts. In multicolor printing, the repeated expansion of the substrate therefore causes the first printed image to be stretched more than subsequent images. To compensate for this, it is common practice to tension the printing forms, and especially the printing plates, in the downstream printing units to a sufficient degree, in order to apply already stretched images. This ensures that the changes in length of the successively applied images are ultimately consistent. Since expansion occurs in every printing unit, the last printing plate to be transferred must be stretched the most. At high clamping forces, the leading end of the printing plate may no longer be held securely enough in its clamping device, causing it to change its position relative to the plate cylinder. This alters the position of the transferred printed image on the sheet and is therefore undesirable. Through the DE 195 11 956 A1 A clamping device for a plate cylinder is known, comprising an outer counter-pressure surface, a spring pack consisting of several leaf springs forming a clamping gap, and a hose that can be filled with compressed air to deflect the leaf springs and open the clamping gap. Through the DE 37 310 39 A1 A clamping device for a plate cylinder is known, comprising a rear clamping device arranged in a movable slide. The rear clamping device is moved by a toggle lever mechanism, with a spring for closing and a compressed air-fillable hose for opening. Through the DE 295 06 864 U1 and the DE 10 2007 002 785 A1 A clamping device for pressure plates is known, comprising a toggle lever mechanism and two hoses, each fillable with compressed air, one of which serves to open and the other to close the clamping device. The clamping gap remains closed when the toggle lever mechanism moves past a dead center and is abutted against a stop. The toggle lever mechanism includes a spring that pushes it out of its extended position. The invention is based on the objective of creating a plate cylinder with a clamping device and a method for operating a printing press. The problem is solved according to the invention by the features of claim 1 and the features of claim 10. A plate cylinder has at least one cylinder channel in which a clamping device for clamping at least one plate-shaped elevator, for example, designed as a pressure plate, is arranged. The clamping device has at least one clamping element, for example, designed as a slide, particularly for clamping at least one elevator, which is movably arranged with respect to a clamping direction by means of a clamping drive, preferably designed as a clamping hose. The clamping device has at least one rear holding device for holding and, more preferably, at least one clamping device for clamping a trailing end of the at least one elevator, which is movably arranged with the clamping element with respect to the clamping direction. The clamping device has at least one front clamping device for clamping a leading end of the at least one elevator. The front clamping device has a fixed front counter-pressure surface which, together with at least one movable front pressure surface, forms a front clamping gap. The front clamping device has at least one closing element comprising a spring element, wherein a spring force of the spring element of the at least one closing element directly or indirectly counteracts the creation and/or increase of a gap between the at least one front pressure surface and the front counter-pressure surface, particularly when the front clamping device is already open. The at least one closing element is, for example, designed as a toggle lever mechanism with at least one spring forcing the toggle lever mechanism into its extended position, or as at least one leaf spring. Leaf springs are particularly simple in design and cost-effective. The front clamping device has at least one front opening drive which is arranged to act on the at least one closing element to open the front clamping gap – in particular, to be capable of actively acting on it. The front clamping device has at least one front clamping drive, which is distinct from the front opening drive and is arranged to act on the at least one closing means – in particular to be capable of actively acting on it – in order to close the front clamping gap. This offers the advantage that the clamping force of the front clamping device can be increased using simple, space-saving, and cost-effective means, particularly when using a leaf spring and/or a toggle lever mechanism near the dead center. This ensures secure fixation of the leading end of the elevator even under high clamping forces. In a further development, at least one locking element is preferably designed as a spring assembly consisting of se