HK1117465A - Method and device for switching between single-sided or straight printing mode and perfecting or recto/verso printing mode in a sheet-processing machine and reversing drum having the device - Google Patents

Description

Method and device for converting a mode of operation from front-side printing to double-side printing

Technical Field

When switching the mode of operation from front-side printing to duplex printing, the cam-controlled grippers must be adapted to the pivoting movement and the opening time. To this end, either the cam roller is moved onto the control cam or the control cam is moved under the cam roller. Another possibility is to stop the movement of the grippers by partial locking.

Background

DE390110609, for example, discloses a reversing device in which a carriage carrying a cam roller is moved during the changeover from front-side printing to duplex printing. By this measure, the cam rollers are in contact with the respectively adjacent control cams.

The demand for increasingly faster production from printing presses results in high centrifugal forces on the cam rollers due to the increased circumferential speed of the paper-guiding cylinder. Therefore, a strong pressing force is required in order to avoid the cam roller from lifting from the control cam. When switching operating modes, too high a contact pressure can lead to high friction forces when moving the cam roller or the control cam.

Disclosure of Invention

The object of the invention is to provide a method and a device, by means of which the changeover of the gripper control on the reversing cylinder can be effected with little effort.

According to the invention, a method for switching a gripper system of a reversing cylinder from front-side printing to duplex printing or vice versa is proposed, wherein the gripper pivoting and opening movement is generated by a cam control device, wherein a control roller is first locked in a position at a distance from a control cam; locking the other control roller at a position spaced from the other control cam; the conversion of the gripper system is then performed.

According to the invention, a device for locking a control roller in a position which is spaced apart from the control cam interacting with the control roller is also proposed, wherein each control roller is provided with a locking element; the locking element is arranged on an axially displaceable adjusting unit of a tumble drum and is arranged to be brought from a locking position into a locking position by means of an actuator.

A particular advantage of the invention is that the necessary changeover process in the reversing cylinder from the recto-verso printing operation to the recto-verso printing operation requires only a small force. By this measure, the life of the control roller and the control cam can be increased.

This reduction in friction is advantageously achieved by lifting the control roller, which is pressed by spring force against the control cam, before the start of the adjustment process.

Particularly advantageous is an actuator arrangement in which the drum is fixedly arranged, for example a pneumatic cylinder for indirectly locking the control roller in the raised position. The pneumatic cylinder is supplied with compressed air by rotation.

In a further advantageous embodiment: the pivotable toothed segment, on which the cam roller is mounted, is directly locked by means of a pivoting lever.

In a further advantageous embodiment, the toothed segment is pivoted by a fixedly arranged device, i.e. an electric motor spindle drive unit, into a position in which the control roller is spaced apart from the control cam.

Drawings

Embodiments of the invention are shown in the drawings and described below. Wherein:

FIG. 1 is a schematic cross-sectional view of a sheet-fed rotary printing press;

FIG. 2 is a schematic top view of the sheet reversing cylinder;

FIG. 3 is a view of the locking mechanism;

FIG. 4 is section 4-4 of FIG. 3;

FIG. 5 is a side view of the tumble drum with the cam roller raised;

FIG. 6 is another embodiment of a locking member fixedly disposed;

figure 7 a locking element acts on a third embodiment of the sector gear.

Detailed Description

A machine for processing sheets 7, such as a printing press 1, has a feeder 2, at least one printing unit 3 or 4 and a delivery 6. The individual sheets 7 are removed from the stack 8 and fed to the printing units 3 and 4 in individual or scaled form via a feed table 9. These printing couples 3 and 4 each comprise a plate cylinder 11, 12 in a known manner. The plate cylinders 11 and 12 each have a device 13, 14 for fixing the flexible printing plates. Furthermore, a device 16, 17 for semiautomatic or fully automatic plate change is assigned to each plate cylinder 11, 12.

The pile 8 is located on a stacking board 10 which can be lifted and lowered controllably. The sheets 7 are removed from the top side of the stack 8 by means of a so-called suction head 18, which suction head 18 essentially has a plurality of separating and transfer nozzles (Hub-und schlepppauger) 19, 21 for separating the sheets 7. Furthermore, a blowing device 22 for blowing loose the upper paper ply and a detection element 23 for tracking the pile are provided. In order to align the stack 8, in particular the upper sheet 7 of the stack 8, a plurality of lateral and rear stops 24 are provided.

Between the two printing cylinders 31 and 41, a three-cylinder reversing device 26 is provided, which three-cylinder reversing device 26 comprises a transfer cylinder 27, a storage cylinder 28 and a reversing cylinder 29. The reversing cylinder 29 has a so-called gripper system 32 for reversing the sheets in a reverse printing operation. Other cylinders that guide the sheets each have two gripper systems for sheet transport. The gripper system 32 is formed by at least one rigid gripper 33 and one elastic gripper 34, the gripper 33 forming a gripper seat in a front-side printing operation, and the gripper 34 forming a gripper finger in a front-side printing operation. In a double-sided printing operation, the grippers 33 and 34 can pivot about a common axis 36. The gripper 33 is located on a gripper shaft 37, which gripper shaft 37 is concentrically surrounded by a gripper tube 38. The gripper 34 is located on a gripper tube 38. The entire gripper system 32 is mounted pivotably on the reversing cylinder 29.

At one end of the gripper tube 38 there is a drive pinion 40, which drive pinion 40 meshes with a sector gear 42. The sector gear 42 has a bearing journal 43, by means of which bearing journal 43 the sector gear 42 is pivotably mounted on the tumble drum 29. The control roller 44 is disposed opposite the shaft 43 in a staggered manner and is rotatably supported on the sector gear 42. The control roller 44 is in operative contact with a first control cam 46 during the front-side printing operation. For a reverse printing run, the control roller 44 is arranged in operative contact with a second control cam 47. The control cams 47, 57 control the oscillating movement of the gripper system 32 in the double-sided printing operation. The control cams 46, 56 control the gripper system 32 in a recto-printing run.

On the side opposite to the drive pinion 40, a pinion 51 is provided on one end of the gripper shaft 37, the pinion 51 meshing with another sector gear 52. The sector gear 52 is pivotably supported on the tumble drum 29 by means of a bearing journal 53. A control roller 54, which is rotatably mounted on the toothed segment 52, is operatively connected to a control cam 56. A control cam 57 for a reverse printing operation is arranged in parallel beside the control cam 56. The shafts 43, 53 are connected to one another by means of a pretensioned torsion spring 58. By this arrangement, the control rollers 44, 54 are constantly pressed against the control cams 46, 47 assigned thereto; 56. and 57.

Fig. 3 shows a torsion spring 58, which is arranged between the bearing journals 43, 53 of the pivotable toothed segment 42, 52. The bearing journals 43, 53 each have at least one stop 61, 62, which, during operation, together with the bearing journals 43, 53, oscillate back and forth about the axis 63 of the torsion spring 58.

Each stop 61, 62 is provided with a locking element, for example in the form of a wedge 64, 66, which can be pulled in or out by means of an actuator, for example a pneumatic cylinder 67, 68, in the distance a between the stop 61, 62 and an adjustable abutment 69, 71 provided on the tilting roller 29.

Before the reversing cylinder 29 is switched, for example, from front-side printing to duplex printing (in which the control rollers 44, 54 are out of contact with the control cams 46, 56 and are in contact with the control cams 47, 57), the control rollers 44, 54 are locked in a position raised from the control cams. For this purpose, the tumble drum 29 is first stopped in a first position in which one of the two control rollers, for example the control roller 44, is deflected further than in the switching position. At the same time, the correspondingly assigned toothed segment and the stop on the journal are also deflected, so that the gap between the stop 61 and the abutment 69 with the distance a is set. The wedge 64 is moved into this gap a by means of a pneumatic cylinder 67. In a further step, the tumble drum 29 is rotated forward or backward to such an extent that the second control roller 54 is lifted from the control cam 46. The locking in this state takes place in accordance with the first control roller in such a way that the wedge 66 moves into the gap a between the stop 62 and the abutment 71. Subsequently, the reverse roller 29 is turned to the switching position. In this position, the two control rollers 44, 54 are lifted from the control cams 46, 56, as shown in fig. 5.

After the two control rollers 44, 54 have been lifted off their control cams, an adjusting unit, for example a carriage 50, carrying the control rollers 44, 54 is moved in the axial direction until the control rollers 44, 54 are arranged in the region of the parallel control cams 47, 57 for the double-sided printing operation. As a result of the entry of the respective tumble drum position, the control rollers 44, 54 again come into contact with the control cam. This measure allows a rotation of the bearing journal and thus an increase in the clearance a between the stop and the abutment, so that the wedges 64, 66 can be pulled out one after the other with virtually no friction. The conversion process is thus ended.

In the second exemplary embodiment of fig. 6: a remotely controllable actuator 72, for example in the form of an electric motor-spindle drive 73, is always mounted fixedly on the side base frame and has a locking element 75 with a bearing surface 74, which bearing surface 74 acts on a bearing roller 76, which bearing roller 76 is rotatably arranged on the toothed segments 42, 52. By this means, the toothed segment 42, 52 together with the control roller 44, 54 arranged thereon is lifted from its control cam 46, 56 independently of the roller position. The support surface 74 is formed so wide in the axial direction of the reversing cylinder 29 that the support roller 76 can roll on the support surface 74 during a changeover process from front-side printing to duplex printing or vice versa.

In the third exemplary embodiment of fig. 7: the toothed segments 42, 52 carrying the control rollers 44, 54 are fixed in a position in which the respective control roller 44, 54 is lifted from the respectively associated control cam. For this purpose, an actuator in the form of, for example, a pneumatic cylinder 76 is provided on the tumble drum 29, which actuator deflects a lever 78 provided with a roller guide 77 from a "positioning position" into a "locking position". In the locked position, the lever 78 is in operative contact with a rotatable supporting roller 79 arranged on the sector gear 52, which supporting roller 79 can roll on the roller guide 77 during the changeover from front-side printing to duplex printing.

Reference number table

1 printing machine 27 transfer cylinder

2 feeder 28 storage cylinder

3 printing unit 29 inverting cylinder

4 printing device 31 printing cylinder

6 delivery 32 gripper system

7 sheet 33 gripper (rigid)

8 pile 34 gripper (elastic)

9 paper conveying table 36 axis

10 pile of paper boards 37 gripper shaft

11 printing cylinder 38 gripper tube

12 plate cylinder 40 pinion

13 plate fixing device 41 printing cylinder

14 printing plate fixing device 42 sector gear

16 plate changing device 43 support neck

17 plate changing device 44 control roller

18 suction head 46 control cam

19 paper-separating suction nozzle 47 control cam

21 transfer nozzle 50 adjusting unit (carriage)

22 blower 51 pinion

23 detecting element 52 sector gear

24 stop 53 support neck

26 the turning device 54 controls the roller

56 control cam

57 control cam

58 torsion spring

61 stop

62 stop

63 axis of rotation

64 wedge block

66 wedge block

67 pneumatic cylinder

68 pneumatic cylinder

69 support

71 support

72 actuator

73 electric motor-spindle drive

74 support surface

75 locking element

76 actuator

77 roller guide device

78 Lever

79 supporting roller

a gap

Claims (9)

1. Method for switching a gripper system of a reversing cylinder from front printing to duplex printing or vice versa, wherein the gripper pivoting and opening movements are generated by a cam control, characterized in that a control roller (44) is first locked in a position at a distance from a control cam (46); subsequently, the other control roller (54) is locked in a position at a distance from the other control cam (56); the conversion of the gripper system is then performed.

2. A method as claimed in claim 1, characterised in that the spaced-apart positions are produced by rotation of a tumbler (29).

3. The method as claimed in claim 1, characterized in that the spaced-apart positions are produced by actuators which actively deflect the control rollers (44, 54) until a corresponding spacing from the respective control cam is produced.

4. A device for locking a control roller in a position which is at a distance from the control cam co-operating with the control roller, characterized in that each control roller (44; 54) is provided with a locking element (64; 66); the locking element (64, 66; 78) is arranged on an axially displaceable adjusting unit (50) of a tumble drum (29) and is arranged to be brought from a positioning position into a locking position by means of an actuator (67, 68; 76).

5. A device according to claim 4, characterized in that the locking element (64, 66) is movably supported in the gap (a) between a stop (61; 62) and a seat (69; 71) of the adjusting unit (50) of the tumble drum (29).

6. A device according to claim 4, characterized in that the stop (61; 62) is arranged on a bearing journal (43; 53) of the sector gear (42; 52) carrying the control roller (44; 54).

7. A device as claimed in claim 4, characterized in that the locking element (78) is configured as a guide (77) and is movably arranged in functional contact with a bearing roller (79) of one of the toothed segments (42, 52).

8. A device for locking a control roller in a position which is spaced apart from a control cam which interacts with the control roller, characterized in that a locking element (75) is fixedly arranged and arranged to be movably supported against a supporting roller (76) of a toothed segment (42; 52) by means of a motor-gear unit (73).

9. A reversing cylinder having a device according to one of the preceding claims 4 to 8, characterized in that the reversing cylinder (29) is installed in a printing press (1) for processing sheets.