GB2306948A

GB2306948A - Rotary printing presses including sheet guiding drum

Info

Publication number: GB2306948A
Application number: GB9623425A
Authority: GB
Inventors: Helmut Schild
Original assignee: MAN Roland Druckmaschinen AG
Current assignee: Manroland AG
Priority date: 1995-11-11
Filing date: 1996-11-11
Publication date: 1997-05-14
Anticipated expiration: 2016-11-11
Also published as: DE19542160C1; GB2306948B; GB9623425D0; FR2741007A1; FR2741007B1; JP2786430B2; JPH09164658A

Description

2306948 1 - ROTARY PRINTING PRESSES INCLUDING SHEET GUIDING DRUMS The

invention relates to rotary printing presses including sheet guiding drums e.g. between the printing units or finishing/further processing units. The drums carry one or more gripper bridges which are distributed evenly about the periphery of the drum and which can be adjusted in remotely operable fashion to different thicknesses of material to be printed.

According to DE 3 428 668 C2, a central gripper support bar adjustment for double and multiple size guiding drums is known. Means engaging against the gripper supports allow the individual adjustment of each support and on these means positioning means adjusting the gripper supports overall act, which can be actuated by a central adjustment device arranged on the drum body. The central adjustment device can, in this connection, be driven by motor and can be controlled from a control desk.

From DE 4 233 422 Cl, a sheet gripper device for rotary printing presses is known which should guarantee a register exact sheet transfer. The gripper support bar is, in this connection, guided substantially radially - 2 movable in a linear guide and has on the end faces a roller which, in the region of sheet transfer, forms a roller matching with in each case a control cam congruently fixed in the side frames. By means of the control cam on sheet transfer, the gripper support bar is moved down/upwards.

According to DE 4 337 578 Al, a sheet guiding drum for printing presses is known which has a drive motor fixed with respect to the frame projecting into the drum trunnion of the drum, which via a corresponding linkage with central adjusting means moves the gripper support bar via a positioning device with push wedges in the substantially radial direction.

From GB 2 098 966 A, a device for positioning the gripper support of a gripper bridge of a sheet guiding cylinder is known. The positioning of the gripper support, depending upon the thickness of the material to be printed to be worked with, takes place by means of an adjusting rod which is arranged in the cylinder axial direction shiftably against spring force by means of a screw below a gripper support running over the entire cylinder length.

It is disadvantageous that with a centrally arranged adjustment of the gripper support bar to the respective thickness of the material to be printed, high outlay is necessary in guiding drums with several gripper bridges a base and fine adjustment of the gripper support bars relative to one another is necessary in order to make possible an exact common adjustment of all gripper support bars. With stepless adjustment, hysteresis often arises, which is determined by friction and play in the linkages.

According to the present invention there is provided a rotary printing press including a sheet guiding drum, the drum carrying at least one gripper bridge arranged at the periphery of the drum and constituted by gripper shaft, grippers and gripper support bar adjustable substantially in the radial direction of the drum to various thicknesses of material to be printed and including a corresponding positioning device, wherein the positioning device includes a rotatable member towards which the gripper support bar is spring biased, and on which it rests via one of a plurality of pressure pieces, at a free end of the rotatable member a roller lever is swivellably arranged, wherein the roller lever is arranged to adopt one of several latched positions corresponding to the number of pressure pieces by engagement with a spring latch mounted on the drum, and swivelling of the roller lever being effected by its passing over a swivellably mounted control cam having upper and lower cam paths, mounted via at least one rotary pivot on the frame of the press, and the press including an actuation device for swivelling the cam, whereby the roller of the roller lever can be periodically coupled with the control cam while the drum carries out a rotary movement, to effect rotation of the rotatable member from one latched position to another. By constructing the press in this way it is possible to undertake a non-central individual adjustment (high setting or low setting) of all gripper bridges of sheet guiding drums in the press to the thickness of the material to be printed to be worked on in common.

The solution in accordance with the invention is suited - 4 predominantly for sheet guiding drums (looping drums) but it is, in addition to this, also useful on sheet guiding cylinders and is accordingly suited also for gripper support bar adjustment in feeder drums or pre-gripper cylinders, and the term "sheet guiding drum" used herein is accordingly to be construed broadly.

The present invention is particularly suitable for one to quadruple size drums, taken on a single size impression cylinder diameter, with the corresponding number of gripper bridges arranged symmetrically around the periphery. It serves for working on material to be printed with differing thicknesses such as, e.g. paper or card. The remote controllable, non-central individual is adjustment of the gripper supports of all sheet guiding drums in one printing press shortens changeover times and minimises subjective influences. Furthermore, the invention constitutes a solution which can be economically automated. The actuation device on the side frame is directed to the circle of positioning devices which arises in the printing operation. Starting from an actuation device fixed to the side frame, the transfer of the adjustment movement of the positioning devices on the drum body takes place by means of a periodic coupling of the control cam with the roller levers arranged on the rotating sheet guiding drum and set relative to the positioning device. By means of the actuation device and the control cam, the gripper support bars of a sheet guiding drum can be adjusted via the positioning device to the corresponding thickness of material to be printed stepwise. By means of the stepwise adjustment of each gripper support bar, hysteresis phenomena are noticeably reduced. In practical printing, it has emerged that a continuous stepless repositioning of the gripper support bars to the thickness of the material to be printed is not absolutely necessary. Rather more, positional changes in several steps, preferably two or three, suffice. For paper working (thinner material to be printed), the gripper support bar is high and for working with card (thicker material to be printed), the gripper support bar is to be set deep. The sheet guiding drums of the printing presses do not have to be turned into a defined angular position for the adjustment process, but all of the gripper support bars are, with a low rotational speed, e.g. with the printing press creeping forward, moved in their circle past the control cams so that periodically a coupling adjusting the positioning device takes place between roller lever and control cam.

For further automatisation in the control desk of a printing machine, the activation of the actuation device acting on the positioning device is controlled either manually by the operator or by a device for determining the thickness of the material to be printed, which is connected by means of appropriate circuit technology with the control desk.

The invention is illustrated by way of example with reference to an exemplary embodiment shown in the accompanying drawings, in which:

Figure 1 is a diagrammatic partial front view of part of a double size drum Figure 2 is a side view of the drum part according to section A-A in Figure 1, Figure 3 is a partial side view partly in section, according to section lines B-B on Figures 1 and 4, showing the gripper support positioning device in detail, Figure 4 is a partial front view of a gripper bridge and positioning device, and Figure 5 shows diagrammatically the arrangement of control cam and actuation device on the side frame of the press.

Referring to Figure 1, a sheet guiding drum 1 is arranged in an offset rotary printing press subsequent to the impression cylinder of the preceding printing unit, and an impression cylinder of a further printing unit is arranged after the drum 1. Taken with respect to a single size impression cylinder, the drum 1 is equipped with a double size drum body and accordingly bears two gripper bridges 13. On the periphery of the drum 1, both gripper bridges 13 are arranged symmetrically distributed (180' offset). Each gripper bridge 13 consists of a gripper shaft, grippers 18 and gripper support bar 2 adjustable in the substantially radial direction. The gripper support bar 2 carries for each gripper 18, support blocks arranged thereto for the individual gripper support.

The drum 1 is received with both drum trunnions rotatably respectively each in a bearing of a side frame 11. Each gripper support bar 2 has a positioning device 3 arranged relative thereto which, dependent upon the thickness of the material to be printed, works in steps the high or low setting of the gripper support bar 2. The positioning device 3 is taken up as a positioning shaft rotationally movable in bearings 5 on the drum body 1.

7 - In the case of a double sized drum 1, there are accordingly arranged two positioning devices 3. The gripper support bar 2 is supported spring loaded against the positioning device 3. Arranged adjustably on the gripper support bar 2 are pressure pieces 4 corresponding to the number of the desired steps. In the present example, the gripper support bar 2 is adjusted in three steps, and accordingly three pressure pieces 4 are arranged on the gripper support bar 2. The pressure pieces 4 are supported on the positioning device 3, wherein the positioning device 3 has cutouts 14 at its periphery which are operatively connected with corresponding pressure pieces 4 so that always a pressure piece 4 is supported on the positioning device 3 of the gripper support bar 2. The pressure pieces 4 always bear on the radius of the positioning device 3, so that positioning errors have no influence on the adjustment of the gripper support bar 2. Arranged at the free end of the positioning device 3 is a roller lever 6. The roller lever 6 carries a roller 7 as well as corresponding to the desired switching stages, in the present case with three switching stages, three latch positions 9. A latch 8 engages in one of the latch positions 9 which is connected with a compression spring 10. The compression spring 10, preferably a gas spring, is rotatably mounted on the end face of the drum 1. On rotating the drum, there arises by the positioning device 3 or the roller lever 6, a notional circle. Flush to this circle is arranged on a neighbouring side frame 11 a control cam 12. The control cam 12 has an upper and lower cam path which run substantially in the shape of a funnel from outwards towards the interior. The control cam 12 is swivellably arranged in at least one rotational pivot 16 in the side frame 11 and furthermore is coupled with an actuation device 15, in the present case an adjusting motor, as well as an energy supply 17. In Fig. 5, two control cams 12 are illustrated which both get narrower towards the interior like a funnel. Each control cam 12 is swivellably mounted on a rotational pivot 16 and has a common rotatable coupling with the actuation device 15 as well as the subsequently arranged energy supply.

is The mode of operation is as follows: A drum 1 takes over a printed sheet from the impression cylinder of a previously arranged printing unit and transfers this to the impression cylinder of the subsequently arranged printing unit. If a material to be printed having a changed thickness (weight) is to be worked with, it is necessary to set the gripper support bars 2 higher or lower. The energy supply 17 is actuated manually or also automatically via a control station. The actuation device 15, in this case an adjusting motor, is controlled via technical circuitry. This has the effect that the actuation device 15 swivels the control cam 12 so that an altered cam guidance results. The printing press is put into rotation with a small rotational speed (creeping movement). In this connection the roller 7 of the roller lever 6 runs through the funnel-shaped control cam 12, the roller 7 comes into contact with the upper or lower cam path (depending upon the actual latch position in each case) and is guided in the cam path in such a fashion that the roller lever 6 is swivelled into the desired new latched position 9. The compression spring 10 holds the desired latch position 9 by means of the latch 8 so that the latched position 9 taken up is fixed. During the periodic coupling of roller 7 and control cam 12, the positioning device 3 is also swivelled in its bearings so that the previous pressure piece 4 dips into the recess 14 and the neighbouring pressure piece 4 takes over the support of the gripper support bar 2. At least one pressure piece 4 always lies on the positioning device 3. The drum body 1 can accordingly be actuated in forward running direction or backwards running direction. Because of the funnel-shaped construction of the control cam 12, the desired latch position 9 can be adjusted each time. In order to carry out the adjusting process on all gripper bridges 13, it is necessary for each drum 1 of a printing press to carry out only one cylinder revolution. This has the advantage that starting from a central position, even printing presses with several successively arranged printing units can be adjusted in sequence switching or also simultaneously.

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Claims

1. A rotary printing press including a sheet guiding drum, the drum carrying at least one gripper bridge arranged at the periphery of the drum and constituted by gripper shaft, grippers and gripper support bar adjustable substantially in the radial direction of the drum to various thicknesses of material to be printed and including a corresponding positioning device, wherein the positioning device includes a rotatable member towards which the gripper support bar is spring biased, and on which it rests via one of a plurality of pressure pieces, at a free end of the rotatable member a roller lever is swivellably arranged, wherein the roller lever is arranged to adopt one of several latched positions corresponding to the number of pressure pieces by engagement with a spring latch mounted on the drum, and swivelling of the roller lever being effected by its passing over a swivellably mounted control cam having upper and lower cam paths, mounted via at least one rotary pivot on the frame of the press, and the press including an actuation device for swivelling the cam, whereby the roller of the roller lever can be periodically coupled with the control cam while the drum carries out a rotary movement, to effect rotation of the rotatable member from one latched position to another.

2. A rotary printing press according to Claim 1, wherein the rotatable member is a positioning shaft rotatably arranged in bearings of the drum and extending axially parallel to the gripper support bar.

3. A rotary printing press according to Claim 1 or 2, wherein the pressure pieces are arranged adjustably - 1 1 - against the gripper support bar.

4. A rotary printing press according to any one of Claims 1 to 3, wherein the cam paths of the control cam run in the shape of a funnel from outwards to inwards.

5. A rotary printing press including means to adjust gripper supports on a sheet guiding drum substantially as hereinbefore described with reference to the accompanying drawings.