EP4208345B1 - Device for clamping a sheet-like roll cover around a roll - Google Patents

Description

The present invention relates to a device for tensioning an arcuate roller cover around the outer surface of a rotatable roller according to the preamble of claim 1.

From the EP0401500A2 A device for adjusting and clamping flexible printing plates on the plate cylinder of rotary printing machines is known. A pair of clamping rails is oriented parallel to the axis of rotation of the plate cylinder. The clamping rails extend almost the entire length of the plate cylinder and are pivotably mounted on the cylinder body by levers. This makes it possible to correct angular errors in the printed image by slightly moving the printing plate on the plate cylinder.

With the known devices, manually pulling a roller cover onto the roller is cumbersome. The cover often slips out of the first tensioning rail of a pair in sections before it is completely hooked into the second tensioning rail and can be secured by tensioning. Wide roller covers in particular are unwieldy and have to be pulled on by two people together.

Pressing the roller cover into an undersized groove requires a lot of force and makes it difficult to remove the roller cover. In addition, the force required significantly increases the risk of damage to the roller, especially if hammers are used as an aid.

To make registration corrections, the DE9318599U1 the targeted inclination of the printing plate on the plate cylinder. For this purpose, a pair of clamping rails arranged in succession in the direction of rotation is provided. One of the clamping rails is arranged in the manner of a trapezoidal four-bar linkage in the Plate cylinder. The four-bar linkage is connected to the second tensioning rail of the pair via levers and joints in such a way that an axial displacement of the first rail simultaneously causes it to pivot.

To prevent the printing plate from accidentally slipping out of the clamping rail, the US4831931A Clamping elements are available. These are suitable for clamping the printing plate in a threaded area against the clamping rail. US5488904 discloses a device for tensioning at least one sheet-shaped printing cliché or printing plate.

A concave expansion of the printing plate can be compensated with a DE102010045036A1 described split tensioning rail. For this purpose, the tensioning rail is divided in the axial direction into several segments, which can be individually subjected to a tensioning force. Successively hanging the roller cover in the partial rail and immediately tensioning each one can make handling easier when pulling it on, but leads to undesirable uneven stretching of the roller cover. In particular, the sequence of the individual tensioning processes influences the stretching and thus the print image.

It is therefore an object of the present invention to provide a device which is improved over the prior art and which overcomes at least one of the disadvantages of the prior art.

The object is achieved with a device having the features of claim 1. Advantageous embodiments emerge from the subclaims.

For this purpose, a clamping device is provided for clamping a roller cover over a casing surface of a rotating roller, whereby the roller can be a printing cylinder and the roller cover can be a printing plate, which has a pair of clamping rails on the casing surface of the roller that are parallel to the axis of rotation of the roller. The clamping rails each form an undercut in the form of a groove into which the leading edge or the trailing edge of the roller cover can be hooked. A first clamping rail of the pair is firmly connected to the printing cylinder.

The second tensioning rail of the pair is made up of several similar partial rails in its longitudinal direction. Each of these partial rails is attached to the carriage of a respective tensioning unit. The carriages can each be moved with one of the partial rails essentially in the circumferential direction. The carriage positions determine the distance of their partial rail from the first tensioning rail of the pair and thus the tension of the roller cover. For this purpose, each tensioning unit is equipped with a separate drive acting on the respective carriage.

The tensioning device comprises a lock associated with the second tensioning rail. The lock is arranged in relation to the second tensioning rail in such a way that when the roller cover is not tensioned, in its closed arrangement it secures the roller cover against accidentally slipping out of the holder of the partial rail and in its open arrangement it releases the roller cover relative to the respective partial rail.

The lock is designed as a lever with a rotation axis such that the legs of the lever can be moved in a plane that is essentially tangential to the roller shell. It is particularly advantageous if the lock is mounted on the slide of a clamping unit and assigned to the partial rail of this clamping unit. This means that the securing or releasing of the roller cover is not influenced by the position of the clamping slide. This prevents the roller cover from being accidentally released if the tension is released prematurely.

Preferably, each of these separate tensioning drives is assigned a common switch. This makes it possible to activate the tensioning units individually. For example, when using a narrow roller cover, tensioning units that are not required can be switched off. In addition, a wide roller cover can be stretched or distorted in a targeted, uneven manner by switching off individual tensioning units.

It is advantageous to arrange several identical clamping units on a common pivoting beam with a pivot axis arranged essentially radially to the roller. Angular errors in the roller cover can be corrected by pivoting this beam.

The swivel beam is preferably assigned a feed device with a controllable actuator. In this way, angle errors in the roller cover can be corrected automatically without manual intervention. A curve control of the swivel movement by means of a cam roller rolling on a curve is particularly advantageous. The design of the curve allows a desired force curve for the swiveling to be set.

The feed device preferably comprises a push rod which is guided into the roller through a hollow shaft. In this way, the movement-sensitive drive elements in particular can be arranged fixed to the frame outside the roller.

Fig. 1

vereinfachte perspektivische Ansicht eines Druckzylinders mit Spannvorrichtung;

Fig. 2

vereinfachte perspektivische Detailansicht einer Zustelleinrichtung zum Schwenken einer Spannvorrichtung;

Fig. 3

vereinfachte Detailansicht einer Zustelleinrichtung zum Schwenken einer Spannvorrichtung;

Fig. 4

vereinfachte Ansicht einer Spanneinheit in unterschiedlichen Zuständen;

Fig. 5

vereinfachte perspektivische Detailansicht einer Spannvorrichtung;

Fig. 6

vereinfachte perspektivische Detailansicht eine Spanneinheit;

Fig. 7

Schaltlogik der Sperren einer Spannvorrichtung.

The invention is then explained using an exemplary embodiment with reference to the figures, to which reference is made for all details not mentioned in detail in the description. The figures show:

Fig.1

simplified perspective view of a printing cylinder with clamping device;

Fig.2

simplified perspective detailed view of a feed device for pivoting a clamping device;

Fig.3

simplified detailed view of a feed device for pivoting a clamping device;

Fig.4

simplified view of a clamping unit in different states;

Fig.5

simplified perspective detailed view of a clamping device;

Fig.6

simplified perspective detailed view of a clamping unit;

Fig.7

Switching logic of the locks of a clamping device.

A pressure cylinder 1 with a clamping device 2 according to the invention is in Fig.1 The outer surface 103 of the central cylinder 10 is penetrated by a channel 17. This channel 17 extends in the axial direction y, parallel to the axis of rotation 100 of the printing cylinder 1 and accommodates the clamping device 2. The printing cylinder is connected to the central cylinder 10 via shaft shoulders 16 arranged on both sides of the central cylinder 10, as shown in Fig.3 shown stored in machine frame 5.

A first tensioning rail 11 and a second tensioning rail 12 together form a pair of tensioning rails of the tensioning device 2. The tensioning rails 11, 12 are axially oriented parallel to one another on the outer surface 103 of the cylinder 10. In the circumferential direction, they have a variable distance 70 from one another. The first tensioning rail 11 and the second tensioning rail 12 each form an undercut 45 in the form of a groove that is open in the circumferential direction of the cylinder 10. The openings of these two grooves face one another. The printing cliché can be hung in them at its leading or trailing edge. By narrowing the distance 70 between the two tensioning rails 11, 12, the hung printing cliché is tensioned and thus fixed on the cylinder 10.

The pair of tensioning rails is mounted on a beam 13 of the tensioning device 2. This beam 13 runs in the axial direction y in the channel 17 of the printing cylinder 1. It is mounted so that it can pivot about an axis 101 running radially to the printing cylinder 1. Slight pivoting 202 of the tensioning rails 11, 12 about the radial axis 101 allows corrections to the angular position of the printed image. A feed device 3 is provided for this correction. For this purpose, the feed device 3 comprises a controllable positioning drive 34. This positioning drive 34 communicates with a controller 6 via data lines 60.

The positioning drive 34 acts on the pivotable beam 13 of the clamping device 2 via a gear that axially penetrates a hollow shaft 16 of the printing cylinder 1. For this purpose, a spindle drive 35 of the feed device 3 connects the positioning drive 34 to a push rod 36 running axially in the hollow shaft 16 of the printing cylinder 1. An arm 37 of the feed device 3 connected to this push rod 36 penetrates an end face 104 of the central cylinder 10 and engages in the channel 17 of the printing cylinder 1. The arm 37 is mounted in the channel 17 by means of a linear guide 33. The linear guide 33 is oriented parallel to the axis of rotation 100 of the printing cylinder 1 and allows the arm 37 an axial linear movement 201. A cam roller 31 is attached to the end of the arm 37 that protrudes into the channel 17. The cam roller 31 interacts with a curve 30 of the swivel beam 13. The beam 13 is supported by a compression spring 32 against the channel 17 in such a way that it always rests against the cam roller 31 of the Feed device 3. By linear displacement 201 of the arm 37, its cam roller 31 rolls on the curve 30 of the beam 13 and thus causes its pivoting movement 202 about its pivot axis 101.

The second clamping rail 12 is made up of several sections 44 arranged one behind the other in the axial direction y. Each of these sections 44 is part of one of several similar clamping units 4. The structure of such a clamping unit is shown in the Fig. 4 to 6 shown. The clamping unit 4 consists of a clamping slide 40. This clamping slide 40 is accommodated by a linear guide 43 on the pivoting beam 13 of the clamping device 2 and carries one of the partial rails 44. The linear guide 43 is oriented essentially radially to the central cylinder 10 of the printing cylinder 1 and determines the direction of the linear clamping movement 200. For this purpose, it comprises two guide rails parallel to one another.

The clamping carriage 40 of the clamping unit 4 is operated by a separate drive. This drive moves the carriage between the two end positions. The end position in which the printing plate is clamped is in Fig. 4a shown. Compression springs 41 hold the clamping slide 40 in this end position and apply the clamping force to the part rail 44. In order to relax the printing plate, the compression springs 41 are overridden by a pneumatic cylinder 42 so that the clamping slide 40 reaches the other end position as in Fig. 4b-d Each clamping unit 40 has a separate switch 38 for its drive. This switch 38 can easily be a manually operated valve, which is not shown in the figures. In this way, individual clamping units 40 can be switched on or off. For automated operation of the clamping units 40, the pressure lines of the individual clamping units 40 are as shown in Fig.7 shown combined into a central pressure line, which contains a mechanically controllable multi-way valve as a common switch 39. The common valve and the respective separate valve are arranged in relation to one another in the manner of an AND circuit.

Each clamping unit 40 comprises a first lock 50, which is assigned to the first clamping rail 11. This is the The first lock 50 is arranged opposite the groove of the first clamping rail 11 and is designed to release the holder for changing the printing plate and to lock it for clamping the printing plate. For this purpose, this first lock 50 is mounted on the pivoting beam 13 of the clamping device 2 and can be a Fig. 4a-c shown closed position 301 and one in Fig. 4d assume the open position 300 shown.

The first lock 50 is designed in the form of a lever 53 with two legs 61, 62 arranged at right angles to one another. It is accommodated in a pivot bearing 54 of the carriage 40 so as to be pivotable about an axis radial to the printing cylinder. In its closed position 301, the first leg 61 of the first lock 50 is aligned parallel to the first clamping rail 11. The opening width 71 between the first clamping rail 11 and the first lock 50 is small, so that the slipping out of an inserted printing plate is reliably prevented. The second leg 62 points in the direction of the second clamping rail 12 and the second contact surface 52 located on its rear side is held by a magnet 55.

In its open position 301, the second leg 62 of the first lock 50 is oriented parallel to the first clamping rail. The opening width 71 is larger than in the closed position 301, so that the printing plate can be easily hung in or removed. The first leg 61 points towards the second clamping rail 12 and is held by the magnet 55 via the first contact surface 51 arranged on its rear side. A handle 57 attached to the lever 53 above the pivot bearing 54 is provided for operating the first lock 50.

A second lock 58 of each clamping unit 4 is arranged on the respective clamping slide 40 and opposite the receiving groove of the associated partial rail. Its function and structure correspond to the first lock 50 and is therefore not explained further.

The clamping device 2 has a plurality of identical clamping units 40 as described, which are arranged on the common pivoting beam 13.

The individual states of a single clamping unit 4 when changing and clamping a printing plate are shown in the Fig. 4a-d The printing plate itself is not shown. Fig. 4a begins with the tensioned state in which the cliché is tensioned and both locks 50, 58 are held in their closed position 301. If the separate valve is open, the pneumatic cylinder 42 overrides the tension spring 41 when the common multi-way valve is opened, so that the slide 40 is moved into the Fig. 4b The distance 70 between the clamping rails 11, 12 is increased and a suspended printing plate is relaxed. The opening of the second lock 58 according to Fig. 4c releases a first edge of the printing plate so that it can be unwound from the printing cylinder. If the first lock is also in its open position 300, as in Fig. 4d As shown, the printing plate can be completely removed. The process of applying and clamping a plate is carried out in reverse order.

Reference symbols

1 Pressure cylinder 33 Linear guide 2 Clamping device 34 Positioning drive 3 Feeding device, swiveling 35 Spindle drive 4 Clamping unit 36 Push rod 5 Machine frame 37 poor 6 steering 38 Switch 10 cylinder 39 Group switch 11 first rail 40 Clamping slide 12 second rail 41 Compression spring 13 bar 42 Pneumatic cylinder 15 Pivot bearing 43 Linear guide 16 Hollow shaft 44 Stretcher 17 channel 45 Undercut 20 cover 50 first lock 30 Curve 51 first stop surface 31 Cam roller 52 second stop surface 32 Compression spring 53 lever 54 Pivot bearing 300 open arrangement 55 magnet 301 closed arrangement 56 holder 57 Handle 58 second lock 60 Data line 61 first leg 62 second leg 70 Distance 71 Opening width 100 Rotation axis 101 Swivel axis 103 Shell surface 104 Frontal area 200 linear clamping movement 201 linear feed movement 202 Swivel movement 203 first rotation 204 second rotation

Claims (7)

1. A device for tensioning at least one essentially sheet-like plate or printing plate around essentially the surface area (103) of a printing cylinder (10), wherein the printing cylinder (10) is mounted so as to be rotatable about its axial rotational axis (100), comprising at least

   • a first rail (11) that essentially extends parallel to the rotational axis (100) of the printing cylinder (10) and is arranged on the surface area of the printing cylinder (10),

   • a second rail (12) that essentially extends parallel to the rotational axis (100) of the printing cylinder (10), is arranged on the surface area of the printing cylinder (10) and composed of at least two partial rails (44), wherein

   • the first rail (11) and the second rail (12) respectively have at least one undercut (45) for accommodating the at least one plate or the at least one printing plate in a form-fitting manner, and wherein

   • the at least one first rail (11) and the at least one second rail (12) are spaced apart from one another by a variable distance (70) in the circumferential direction of the printing cylinder (10), as well as

   • two tensioning units (4) that are spaced apart from one another in the direction of the rotational axis (100) of the printing cylinder (10) and respectively at least comprise a slide (40) that essentially can be moved in the circumferential direction of the printing cylinder (10), a drive (42) that is operatively connected to the at least one slide (40) and a partial rail (44) that is arranged on the slide (40) and forms the second rail (12), wherein

   at least one lock (58) is arranged opposite of at least one partial rail (44) of the at least one second rail (12), and wherein the at least one lock (58) alternately has an open arrangement (300) and a closed arrangement (301) with respect to the at least one associated partial rail (44) and forms a closable receptacle together with the at least one associated second partial rail (44),

   characterized in that the at least one lock (58) is formed by a lever (53) that has two limbs (61, 62) and is rotatable about an axis (102), wherein the rotational axis essentially extends essentially radially to the printing cylinder (10) and the two limbs (61, 62) of the lever (53) jointly define a plane, and wherein said plane essentially is aligned perpendicular to the rotational axis of the lock (58).
2. The device according to claim 1, characterized in that the at least two tensioning units (4) respectively have a separate switch (38), which is respectively assigned to the at least one drive (42), and a group of at least two respective tensioning units (4) respectively has another common switch (39), wherein each of the separate switches (38) of the at least two tensioning units (4) of a common group and the at least one common switch (39) of the same common group are interconnected in the form of an AND-circuit.
3. The device according to one of the preceding claims, characterized in that at least one of the at least two tensioning units (4) has at least one lock (58), which is assigned to the at least one partial rail (44) of the same tensioning unit (4).
4. The device according to one of the preceding claims, characterized by a beam (13) that essentially extends parallel to the rotational axis (100) of the printing cylinder (10) and can be at least slightly pivoted relative to the printing cylinder (10) about a pivoting axis (101), wherein the at least two tensioning units (4) are arranged on said beam, and wherein the pivoting axis (101) of the beam (13) extends orthogonal to the rotational axis (100) of the roll (10).
5. The device according to claim 4, characterized by at least one adjustment device (3) of the at least one beam (13) with at least one controllable actuating drive (34), wherein the at least one controllable actuating drive (34) is connected to a control (6) via at least one data line (60) in order to exchange signals.
6. The device according to claim 4 or 5, characterized by at least one cam (30) and at least one cam roller (31) of the adjustment device (3), which rolls on the at least one cam (30).
7. The device according to one of claims 4 to 6, characterized by at least one push rod (36) of the controllable adjustment device (3), wherein the at least one push rod (36) is arranged collinear to the rotational axis (100) of the roll (10) and extends through a hollow shaft (16) of the printing cylinder (10).

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