EP0586876B1 - Device for a controlled separation of waste from printed material - Google Patents

Abstract

The invention relates to a device for the monitored elimination of waste pieces from printed material, especially on a cutting cylinder, the device being characterised by the following features: a cylindrical casing (2) of a cutting cylinder (1) is rotatably accommodated on a cylinder shaft (4). The cylinder shaft (4) has both a high pressure pipe (20, 21) and a low pressure pipe (22, 23). Between the rotatable cylindrical casing (2) and the cylinder shaft (4) there are arranged chambers (26, 27) which are permanently under pressure and are permanently acted upon by a vacuum, while the bores (3) provided in the cylindrical casing (2) of the cutting cylinder (1) alternately function as blowing and sucking apertures during rotation of the cylindrical casing (2). <IMAGE>

Description

The invention relates to a device with a cutting cylinder and means for the controlled removal of waste pieces of printing materials.

From the prior art, DE 32 43 778 A1, a suction air cylinder with a control head for noise reduction is known. A good amount is sucked in through a large number of bores on the jacket of the suction cylinder, which drops off the jacket of the suction cylinder after the atmospheric pressure equalization caused by a control head. The suction cylinder is divided into several chambers for sound absorption during sudden pressure equalization. With this device, a good is detached from the jacket of the suction cylinder only by atmospheric pressure compensation.

DE-PS 1 19 48 75 discloses an apparatus for the appropriate feeding of paper sheets to a blank processing machine. The suction element designed as a suction drum comprises a chamber that is permanently under suction and a second suction chamber that can be controlled under suction. The suction air is applied to the front of the suction drum. The jacket broken through the individual bores rotates together with the drum; Blowing air is not provided on the jacket of the drum.

US 4,407,870 shows a cutting device for the continuous cutting and removal of thin strips of a printed web.
The strip, which is separated from a pair of knives working together with a lower knife, is sucked in by negative pressure and reaches a central bore of the cutting cylinder, from which it is subsequently removed.

A disadvantage of this device is the fact that it requires a large negative pressure volume in order to convey the strip into the interior of the cylinder. Furthermore, this device has limits with regard to the peripheral speed, since the centrifugal forces which occur at high peripheral speeds and act on the strip must be additionally compensated for by the vacuum in the channel. The conveying paths to the inside of the cutting cylinder are too long for high speeds.

DE-U-8 715 419 discloses a stripping device for rotary punching. A stripping cylinder comprises a stationary inner cylinder, which is provided with essentially radial air-impermeable partition walls, and a rotatable outer cylinder surrounding it coaxially. The chambers formed by the partitions are connected to a suction pump or to a pressure pump, the partitions being provided with seals which touch and seal the inner wall of the outer cylinder.

EP 0 468 254 A2 relates to a cross cutter for material webs provided with printed images. A pair of parallel knives is arranged on a knife roller; this works together with a stationary counter knife. Suction and blowing openings are arranged between the knives and can be acted upon alternately with negative pressure and blowing air via a valve control depending on the rotary position of the knife roller. A waste strip cut off during cross cutting is held under vacuum between the knives by the suction and blowing openings and transported to a point where it is blown off by means of blown air and discharged by a suction hood arranged above the knife roller. The valve control for switching between blown air and suction air is arranged on the front side of the knife roller and has rotatably offset inlets and outlets that extend from the suction and blower openings Channels in the connections connected to the knife roller are swept.

Starting from the outlined state of the art, the object of the invention is to reliably detect waste pieces of printing materials during and after the cut, regardless of the specific paper weight, and to keep the air volumes required for this to be small.

According to the invention the object is solved by the features of claim 1.

The advantages associated with this solution are that, thanks to the small, reversible air volumes, a safe function at the highest production speeds is guaranteed. The waste strip is reliably grasped already during the cut and the waste strip is pushed off in a well-defined zone. Since blown air and vacuum are constantly present, the switching times for switching the air types are minimal. Valves and other switching arrangements can largely be dispensed with, since the air types are switched by rotating the cylinder jacket relative to the fixable cylinder axis. A high level of manufacturing accuracy ensures minimal leakage losses both when blowing air and when outside air is drawn in when the cylinder jacket is vacuumed.

It is also provided that the cylinder axis can be variably fixed in its rotational position by a torque arm. On the one hand, this allows a defined position of the cylinder axis to be defined, which it also maintains during production. On the other hand, sensitive twisting of the cylinder axis can be carried out after loosening the clamping screw on the torque arm. In this way one can Adjustment of the chamber position between the cylinder axes and the rotatably mounted cylinder jacket.

In an advantageous embodiment of the subject matter of the invention, the chambers extend essentially over the length of the cutting cylinder parallel to the cylinder axis. This results in an even application of pressure to the surface of the cylinder jacket both by blown air and with a vacuum for handling waste strips of various substrate thicknesses. Starting with thin, fluttering papers from 40 g / m² to thicker materials of around 200 g / m².

It is further provided that the chambers are delimited by at least one sealing strip which can be fixed in the circumferential direction on the cylinder axis. As a result, the length of the chambers can be shortened or extended, depending on the requirements. The chambers form circular arc-shaped sectors on the cylinder axis in the circumferential direction, which favors a simple and inexpensive blown air supply or vacuum application through bores in the cylinder axis.

In a favorable embodiment of the idea on which the invention is based, the cylinder jacket is arranged such that it can be driven separately via bearings on the cylinder axis. The cylinder jacket on the cylinder axis is driven by a pulley arranged on a cylinder journal. This drive configuration allows the rotating cylinder jacket to be used as a switching element for changing the types of air with which the bores on the circumference of the cylinder jacket are applied. Valves or throttles can be completely dispensed with, since the blown air chamber and the suction air chamber are permanently pressurized and the air changeover is only effected by the rotation of the cylinder jacket on the cylinder axis, which receives the sealing strips for chamber separation.

Further developments of the idea on which the invention is based can be seen that in the area of the pair of knives on both sides of the bores between the cutting edges of the knives a transport surface for waste pieces is formed.
This has the advantage that the waste strip to be separated from the printing material web is sucked into the cylinder jacket through the holes in the cylinder jacket after the cut through the first of the knives of the pair of knives. After completing the cut by the second of the pair of knives with a fixed lower knife, the waste strip can be sucked completely onto the transport surface, which considerably increases the conveying security in the device according to the invention.

Finally, the pairs of knives consist of one-piece knives which extend in the axial direction over the entire length of the cylinder jacket. This guarantees an even cut and easier adjustment during the presetting.
Above the cutting cylinder, a suction device takes over pieces of waste from the cylinder jacket of the cutting cylinder. The suction device supports the takeover of the waste strip expelled from the cylinder jacket by the action of blowing air. Since the centrifugal force also acts on them, there is a safe transfer into the suction device. The contour of the blown air chamber in the circumferential direction on the cylinder axis advantageously coincides with the region to which the suction opening of the suction device is located on the circumference of the cutting cylinder.

Fig. 1

eine bedienseitige Lagerung eines Schneidzylinders;

Fig. 2

die Lagerung eines Schneidzylinders auf der Antriebsseite;

Fig. 3

einen Querschnitt durch den Zylindermantel und die Zylinderachse;

Fig. 4

ein Messerpaar auf dem Umfang des Zylindermantels beim Schnitt;

Fig. 5

ein im Transport begriffenes Abfallstück; und

Fig. 6

ein vom Umfang des Zylindermantels abgesaugtes Abfallstück.

The invention is explained in more detail below with reference to the drawing. It shows:

Fig. 1

an operator-side storage of a cutting cylinder;

Fig. 2

the storage of a cutting cylinder on the drive side;

Fig. 3

a cross section through the cylinder jacket and the cylinder axis;

Fig. 4

a pair of knives on the circumference of the cylinder jacket when cutting;

Fig. 5

a piece of waste in transit; and

Fig. 6

a piece of waste extracted from the circumference of the cylinder jacket.

In Fig. 1 an operator-side storage of a cutting cylinder is shown.

A cutting cylinder 1 consists of a cylinder jacket 2, which is pierced by at least two rows of bores 3 running parallel to the axis and a cylinder axis 4. A cylinder journal 5 is connected to the cylinder jacket 2 by screws 6.
Between the cylinder pin 5 and a shoulder of the cylinder axis 4, a bearing 7 is fixed in its axial position on the cylinder axis 4 by a locking ring 8 and a spacer ring 9. By mounting the cylinder jacket 2 on the cylinder axis 4, a rotation of the cylinder jacket 2 relative to the cylinder axis 4 is possible. On the cylinder pin 5, a cone 10 is provided, on which a roller bearing 14 is seated, which in turn by Locknut 12 and locking plate 11 is fixed in position on the cone 10.
Thus, the cylinder jacket 2 is rotatably received in a bushing of the side wall 24 via the cylinder journal 5, the cone 10 and the roller bearing 14, while the cylinder axis 4 passing through the cylinder journal 5 and the cylinder jacket 2 does not rotate. Between the area of the cylinder axis 4, which is penetrated by the blowing and suction air bores 20 and 22 (shown here in dashed lines) and the cylinder journal 5, there is therefore no contact. On the cylinder side, the roller bearing 14 bears against a ring 13 which is supported on a shoulder of the bearing journal 5. The ring 13 or ring 30 in FIG. 2 used for sealing is enclosed by the cylinder-side bearing housing 15, which is held in a socket in the side wall 24 by means of screws 16. The cover 17 is connected to the end face of the cylinder journal 5 by screws. The cover 17 is enclosed by a bearing housing 18 which is fastened on the end face in a bushing in the side wall 24. Accordingly, when the cylinder jacket 2 rotates, both the ring 13 and the cover 17 rotate relative to the side-wall-fixed bearing housings 15 and 18, from which they are separated by narrow air gaps. In addition, a torque support 19 is attached to the side wall 24, which holds the cylinder axis 4 at rest by means of a clamp. The torque arm 19 surrounds the cylinder axis 4 in the area in which the connecting pieces for the blown air supply line 21 and the suction air line 23 are located. These each act on the blown air bore 20 or the suction air bore 22, which pass through the cylinder axis 4 approximately to the center of the axis. The sectors of an annular chamber 25 between the cylinder axis 4 and the inside of the cylinder jacket 2 are acted upon by blowing or suction air by the blowing air bore 20 or the suction air bore 22.
The torque arm has the function of keeping the cylinder axis 4 at rest, so that its position is not approximately Bearing friction is changed. However, the circumferential position of the cylinder axis 4 can be varied by means of the clamping provided on the torque support, which enables the suction and blowing function of the cutting cylinder 1 to be influenced.

2 shows the mounting of the cutting cylinder on the drive side.
The cylinder jacket 2 is rotatable on the cylinder axis 4 by a bearing 7 arranged on the drive-side end of the cylinder axis 4. A cylinder pin 29 is connected to the cylinder jacket 2 by screws 6. On the cylinder pin 29 - analogous to FIG. 1 - the cone 10 is fastened, on which a roller bearing 14 is received by the locking plate 11 and the lock nut 12. The outer ring of the roller bearing 14 is held in position by the bearing housings 15 and 18, which are each received via screws 16 in the side wall 28 on the drive side. In addition, a drive wheel 35 initiating the drive and a belt pulley 32 are rotatably mounted on the extension of the cylinder journal 29. The drive wheel 35 and the pulley 32 are rotatably received by a key 34. The drive wheel 35 and the pulley 32 can be removed after removing a cover 36 from the cylinder journal 29. To pull the pulley 32 from the cylinder journal 29, it is provided with two threads 33.

3 shows a cross section through the cylinder jacket and cylinder axis of a cutting cylinder.

In this illustration it can be seen that the cylinder axis 4 is penetrated by a blowing air bore 20 extending axially to approximately the center of the cutting cylinder 1 and a suction air bore 22. 4 sealing strips 42 are fastened to the circumference of the cylinder axis by screws, through which Position on the circumference of the cylinder axis 4, a pressure chamber 27 and a suction chamber 26 are limited. These chambers are circumferentially bounded by the inside of the cylinder jacket 2, which in turn is penetrated by the rows of bores. Accordingly, if a number of the bores 3 are in contact with the pressure chamber 27, blown air flows to the circumference of the cylinder jacket 2; If a row of the bores 3 of the cylinder jacket is connected to the suction chamber 26, negative pressure is present at the openings of the bores 3 on the cylinder jacket 2. The bores 3 open on the surface of the cylinder jacket 2 in each case between a pair of knives 37, consisting of two knife holders 38, which each hold a knife 41. The knife holders 38 are fixed to the cylinder jacket 2 by means of retaining screws 39. The knives 41 shown here are formed in one piece and can be adjusted by means of adjusting screws 40 such that the positions of the cutting edges of the knives 41 in relation to the outer surface of the cylinder jacket 2 or a machine-fixed lower knife can be adjusted precisely. It would therefore be conceivable to turn these adjusting screws 40 by servomotors provided in the cylinder jacket 2 in order to be able to make this setting. Four blades can be formed on the blades 41, which are designed here with a rectangular cross-section, so that the service life of the blades 41 is favorably influenced. In addition to the geometry of the knives 41 shown here, it is also conceivable to clamp the knife body in the knife holder 38 with only one well-defined cutting edge of a different geometry.

Since the cylinder jacket 2 rotates relative to the cylinder axis 4, the rows of bores 3 alternately come into contact with the pressure chamber 27 or with the suction chamber 26, which results in alternating air switching from suction to blown air and vice versa during the rotation of the cylinder jacket 2 . By changing the positions of the sealing strips 42 which delimit the chambers 26 and 27 the areas of action of suction and blown air are of course adapted to individual requirements, furthermore the sealing strips 42 can be provided with resilient underlays in order to achieve a sealing which follows itself.

The mode of operation of the solution according to the invention is explained schematically below in FIGS. 4 to 6.

FIG. 4 shows the cylinder jacket 2, which is mounted on the cylinder axis 4 and can be driven separately. The suction chamber 26 and the pressure chamber 27 are separated from one another by schematically illustrated sealing strips 42. The cylinder axis 4 is traversed by a blown air bore 20 and a suction air bore 22, which are permanently acted upon. On the circumference of the cylinder jacket 2 - here, for example, two - pairs of knives 37 are arranged opposite one another. Between the individual pairs of knives 37, the bores 3 open on the circumference of the cylinder jacket 2.
In the state shown here, a printing material web 44 moves past a pair of knives 37. The holes 3 assigned to the pair of knives 37 are connected to the suction chamber 26. When the knife 41 is cut with a lower knife, which is not shown here, a specimen is separated from the printing material web 44. The waste strip 45 separated between two printed copies by the cut between the second knife 41 and the lower knife and extending in the axial direction of the cutting cylinder 1 is sucked through the bores 3 at this stage. After a rotation of 90 °, shown in FIG. 5, the waste strip 45 is outside the cutting zone and is transported upwards. The suction chamber 26 is still connected to the bores 3 sucking the waste strip 45 in the cylinder jacket 2, as a result of which the waste strip 45 is held on the circumference.

Upon further rotation of the area of the cylinder jacket 2 which receives the waste strip 45, the latter reaches the sealing strip 41, to which the pressure chamber 27 adjoins. Air then begins to blow immediately through the bores 3 of the cylinder jacket 2. As a result, the waste strip 45, supported by the centrifugal force acting on it, is repelled from the circumference of the cylinder jacket 2. The suction hood 43 arranged above the cutting cylinder 1 sucks off the waste strip 45, so that it is reliably removed from the cylinder jacket 2. The suction hood 43 advantageously extends over a region corresponding to the shape and the course of the pressure chamber 27; this ensures maximum conveying and handling security of the waste strip 45.

The pair of knives 37 opposite the pair of knives 37 leading the waste strips 45 cuts a waste strip 45 out of the printing material web 44 at the same time. The bores 3 of the lower pair of knives 37 are connected to the suction chamber 26 of the cylinder axis 4 and the next material strip 45 to be separated is sucked in.

The switchover of the type of air, whether vacuum or blown air, is thus carried out without switching devices, simply by rotating the cylinder jacket 2 relative to the cylinder axis 4 that can be fixed in one position. The air volume to be reversed can thus be kept small; In addition, the switchover of suction air and blown air takes place close to the place where the air is needed. Pipe systems in which air volumes could be excited to vibrate are absent, so that the effects of blown air or suction air take effect immediately after the switching on the cylinder jacket 2 in the region of the bores 3 between the cutting edges of the knives 41. Thus there are no switching time delays, so that the waste strips 45 to be transported are sucked in and repelled under well-defined conditions.

REFERENCE SIGN LIST

1

Cutting cylinder

2nd

Cylinder jacket

3rd

Holes

4th

Cylinder axis

5

Cylinder journal

6

screw

7

roller bearing

8th

Circlip

9

Spacer ring

10th

cone

11

Lock washer

12th

Locknut

13

ring

14

roller bearing

15

Bearing housing

16

screw

17th

cover

18th

Bearing housing

19th

Torque arm

20th

Blow air hole

21

Blown air supply

22

Suction air hole

23

Suction air line

24th

Side wall

25th

Ring chamber

26

Suction chamber

27

Pressure chamber

28

Side wall

29

Cylinder journal

30th

cover

31

Spacer ring

32

Pulley

33

thread

34

adjusting spring

35

drive wheel

36

cover

37

Pair of knives

38

Knife holder

39

Bracket screw

40

knife

41

Sealing strip

42

Suction hood

43

Substrate

44

Waste strips

Claims (11)

1. Apparatus having a cutting cylinder (1) and means for the controlled removal of waste pieces of printed materials, having chambers (26, 27) which are permanently under pressure and permanently under vacuum and by way of which bores (3) formed in the cylinder shell (2) function alternately as blast openings and as suction openings during the rotation of the cutting cylinder (1), at least one pair of cutters (37) enclosing a row of bores (3) being fastened on the periphery of the cylinder shell (2), characterized in that the cylinder shaft (4), on which the cylinder shell (2) of the cutting cylinder (1) is mounted rotatably and in which a vacuum pipe (20, 22) and a positive pressure supply pipe (22, 23) are provided, can be variably fastened in respect of its rotational position by means of a torque support (19), the chambers (26, 27) being provided between the cylinder shell (2) and the cylinder shaft (4).
2. Apparatus according to Claim 1, characterized in that the chambers (26, 27) extend parallel to the cylinder shaft (4) substantially over the width of the cutting cylinder (1).
3. Apparatus according to Claim 1, characterized in that the chambers (26, 27) are bounded by at least two sealing strips (41) variably fastenable in the circumferential direction on the cylinder shaft (4).
4. Apparatus according to Claim 1, characterized in that on the cylinder shaft (4) the chambers (26, 27) form sectors having a circular arc shape in the circumferential direction.
5. Apparatus according to Claim 1, characterized in that the cylinder shell (2) is mounted on the cylinder shaft (4) by means of rolling-contact bearings (7) such as to be separately drivable.
6. Apparatus according to Claims 1 and 5, characterized in that the cylinder shell (2) mounted on the cylinder shaft (4) is driven by means of a belt pulley (32) disposed on a cylinder journal (29).
7. Apparatus according to Claim 1, characterized in that in the region of the pair of cutters (37) a transport surface for waste strips (45) is formed on both sides of the bores (3) between the cutting edges of the cutters (41).
8. Apparatus according to Claim 1, characterized in that the pair of cutters (37) is composed of one-piece cutters (41) which extend in the axial direction over the entire length of the cylinder shell (2).
9. Apparatus according to Claim 7, characterized in that the positions of the cutters (41) on the cylinder shell (2) can be controlled by adjustment means (40).
10. Apparatus according to Claim 9, characterized in that the operation of adjustment means (40) for changing the positions of the cutters (41) on the cylinder shell (2) is effected by remote control.
11. Apparatus according to Claim 1, characterized in that above the cutting cylinder (1) a suction device (43) takes off waste pieces (45) from the cylinder shell (2).

Images