EP3536503B1 - Clamping device for fastening printing plates on a plate cylinder of a printing machine - Google Patents

Description

The invention relates to a clamping device for fastening printing plates on a plate cylinder of printing machines, consisting of a fixed upper clamping strip and a lower clamping strip, which are arranged in an axially parallel clamping channel and can be brought into a clamping and a change position.

A wide variety of clamping devices for fastening plate-shaped objects, such as clamping devices for fastening printing plates on a plate cylinder of a printing machine, are known, the printing plate being able to be clamped with a defined holding force, but the forces are comparative low and not universally applicable for different panel thicknesses and panel materials (metallic or non-metallic panels) with a consistently high clamping force. A distinction is made between manual and automatically operated clamping and tensioning devices. In the case of automated equipment, the clamping and unclamping of the pressure plates is carried out using integrated electrical, pneumatic or hydraulic servomotors.

It is also known to carry out the automated clamping and unclamping of the printing plates from an actuating device fixed to the frame, the plate cylinder being brought into a corresponding position with the actuating device and the necessary forces for unclamping by applying a force to the end of a pivotable lever to effect.

In order to clamp pressure plates, as is generally known, a lower terminal strip is displaced against the upper terminal strip and held in the clamping position by means of a rigid or flexible element. For this purpose, at least one adjusting element is in operative connection either with a toggle lever mechanism or a leaf spring assembly.

From the DE 102 23 894 A1 a plate clamping device for fastening a printing plate on a plate cylinder of a printing machine is known, in which by means of an upper clamping bar fixed in a cylinder channel and a lower clamping bar which is slidably mounted between a clamping position and a change position. The pushing element is acted upon by an adjusting means and the free lower end of the pushing element is pushed along the inclined guide, while the upper end of the pushing element is relatively displaced about its articulation point on the lower terminal strip and together with the terminal strip.

This process moves the lower terminal strip either towards the upper terminal strip in the clamping position or away from the upper terminal strip into a change position. The adjusting element is designed so that it can both push / pull the pushing element along the inclined guide and also work as a pressure-exerting means.

Is known from the DE 295 06 864 U1 a clamping device for fastening printing plates on plate cylinders of printing machines, consisting of a lower clamping bar fixed to the cylinder and an upper clamping bar which can be brought into a clamping or changing position by toggle lever mechanisms, the toggle lever mechanisms being in a dead position or over-dead position by means of a second tube that can be expanded by a pressure medium can be brought out of the dead position or over dead position by an expandable first tube.

The DE 34 22 530 C1 describes a device for fastening a flexible printing plate on a forme cylinder of a rotary printing press, with clamping rails arranged axially parallel in a cylinder pit, movable for clamping approximately in the circumferential direction of the cylinder, on which clamping rails are mounted pivotably about a longitudinal axis in the manner of a two-armed lever. This device consists of a tensioning rail and a clamping rail supported on this by means of ball joint bolts.

The DE 10 2007 002 785 A1 describes a rotationally symmetrical body with a clamping device for fastening plate-shaped objects. The clamping or tensioning device provided for this purpose comprises a fixed upper clamping bar and a movable lower clamping bar which can be moved into a clamping or changing position, the lower clamping bar having a bearing point on its side facing the interior of the rotationally symmetrical body in which the outwardly directed end of the upper arm of a rigid element (joint) is received and the end of the lower arm is connected to a spring element.

The invention is therefore based on the object of designing the generic clamping device for fastening printing plates on plate cylinders of printing machines in such a way that the most varied of plate materials and plate thicknesses can be clamped with a maximum force without deformation without bearing correction.

According to the invention, the object is achieved by a clamping device according to the features of claim 1. Further refinements are shown in the subclaims.

The clamping device according to the invention makes it possible to modify a device for clamping printing plates that can be realized with simple means so that the holding force that can be realized can be adapted to the plate thickness or to the plate material. The advantages that can be achieved with the invention reside in the simple design of the device which takes up little space.

An essential advantage of this solution according to the invention is that relatively low switching forces have to be applied through the use of a rigid element in connection with a curved guide arranged on the lower region of the clamping rail, while high clamping forces are achieved without damaging the plate-shaped body.

Another advantage is that the very high clamping forces that can be achieved in conjunction with a massive lower clamping strip or clamping rail enable universal use for both metallic (e.g. aluminum) and non-metallic panels (e.g. polyester) with different panel thicknesses.

The clamping device for fastening printing plates on a plate cylinder of printing machines, with a C-shaped upper clamping bar fixed in a plate cylinder channel, one between a clamping position and a change position displaceable lower terminal strip, comprises a switching element which is supported with its upper end portion on an underside of the lower terminal strip and with its lower end portion on a lower portion of the C-shaped upper terminal strip and at least one adjusting means for engaging the switching element, wherein the switching element is designed as a rigid element and is guided with its upper end portion slidingly on a curve guide on the underside of the lower terminal strip during the switching process and is held with its lower portion in a pretensioning device arranged in the lower portion of the C-shaped upper terminal strip.

When using plate-shaped objects made of relatively soft material, the surfaces of the upper terminal strip and the clamping rail facing the plate-shaped object can be provided with a corrugation.

Advantageous further developments and refinements of the invention can be seen from the remaining subclaims and from the exemplary embodiments described in principle below with reference to the drawings.

• Figur 1: eine Klemmvorrichtung in Wechselposition,
• Figur 2: die Klemmvorrichtung in Klemmposition mit geklemmter Platte.
• Figur 3: Einzelheit Klemmleiste / biegesteifes Element
• Figur 4: Einzelheit Klemmleiste / biegesteifes Element
• Figur 5: eine weitere Klemmvorrichtung in Wechselposition
• Figur 6: eine weitere Klemmvorrichtung in Klemmposition

Show it:

• Figure 1 : a clamping device in changing position,
• Figure 2 : the clamping device in clamping position with clamped plate.
• Figure 3 : Detail of the terminal strip / rigid element
• Figure 4 : Detail of the terminal strip / rigid element
• Figure 5 : another clamping device in change position
• Figure 6 : another clamping device in clamping position

The Figure 1 shows a sectional side view of a clamping device in the changing position. In the rotationally symmetrical body, here for example a plate cylinder 1 of a printing press, the clamping device 2 is arranged in a recess provided, the cylinder channel.

The upper clamping strip 3 of the clamping device 2 is fixed, has an approximately C-shaped design and is firmly connected to the plate cylinder 1 . The upper terminal strip 3 has a clamping surface 3.1 , against which the pressure plate 11 to be clamped is clamped or fixed with the lower terminal strip or clamping rail 5 .

A bearing point 5.1 is provided in the lower terminal strip or clamping rail 5 on its side facing the interior of the plate cylinder 1 , the bearing point 5.1 slidingly receiving the upper end of the rigid element 6 .

The clamping strip 3, cover strip 10 and clamping strip or clamping rail 5 extend over the entire width of the plate cylinder 1. The lower end of the rigid element 6 is movably supported by the bearing point 6.1 on the pretensioning device 4 , the spring elements 7 being arranged at a distance from one another are. The gap height and the force to be applied can be adjusted by means of a pretensioning device 4 .

It is also conceivable that the clamping strip 3, cover strip and / or clamping strip or clamping rail 5, these elements are arranged in several parts over the length of the plate cylinder 1 . Over the length of the clamping device 2 , several rigid elements 6 are arranged at equal intervals as possible.

The change position is achieved by corresponding switching of the adjusting elements, here for example by means of the pneumatic pressure medium expandable pressure hose 8 , in which the pressure hose 8 is pressurized, the pressure hose 9 remains unfilled and thus deflects the rigid element 6 to the left, causing the pressure hose to move to the lower Terminal strip or clamping rail 5 acting force is withdrawn.

The Figure 2 shows the clamping device 2 in the clamping position in a sectional side view.

The clamping position is achieved in that the pressure hose 9 is pressurized, the pressure hose 8 remains unfilled. The rigid element 6 pushes the lower terminal strip or clamping rail 5, after the bearing point 5.1 is reached, upwards. So that the pressure plate 11 located in the previous distance is now on the Clamping surface 3.1 of the upper terminal strip 3 pressed and securely fixed and securely clamped between the upper surface of the clamping rail 5 and the clamping surface 3.1 .

By using an adjustable pressure piece 4 or spring element 7, which together form the pretensioning device, it is possible to securely clamp plate-shaped objects on rotationally symmetrical bodies, plate thicknesses of 0.1 to 1 mm, for example, can be clamped with a single clamping device.

The Figures 3 and 4 show in detail the bearing point 5.1 of the upper end section 13 of the rigid element 6 on the lower terminal strip (clamping rail) 5. The lower side of the terminal strip (clamping rail) 5 has a curved guide 12 on which the upper end section 13 of the rigid element 6 during the switching process from the clamping position to the changing position and vice versa. The Figure 3 shows the upper end portion 13 of the rigid element 6, which is rounded semicircular, in connection with the curved guide 12 of the lower clamping strip (clamping rail) 5, while the Figure 4 shows another embodiment.

According to the Figure 4 the upper end section 13 of the rigid element 6 is rounded in a semicircle and has roller inserts 14 spaced apart from one another. By using roller inserts 14 in the upper end sections 13 of the rigid element 6 , friction losses when sliding the upper end section 13 on the curved guide 12 of the lower terminal strip (clamping rail) 5 can be reduced.

The Figure 5 shows a sectional side view of a further embodiment of the clamping device in the change position. In the rotationally symmetrical body, here for example a plate cylinder 1 of a printing press , the clamping device 3 is arranged in a recess provided, the cylinder channel 2 .

The upper clamping bar 3 of the clamping or tensioning device 2 is designed to be stationary and is firmly connected to the plate cylinder 1 . The upper terminal strip 3 has a clamping surface 3.1 , against which the pressure plate to be clamped is clamped or fixed with the lower terminal strip or clamping rail 5 .

In the lower terminal strip or clamping rail 5 , a bearing point 5.1 is provided on its side facing the interior of the plate cylinder 1 , the bearing point 5.1 the upper end portion 13 of the rigid element 6 slidably receives.

The clamping strip 3, cover strip 10 and clamping strip or clamping rail 5 extend over the entire width of the plate cylinder 1. The lower end of the rigid element 6 is movable by the bearing point 6.1 on the pretensioning device, which is formed from pressure pieces 4 and spring elements 7 supported. The spring elements 7 are arranged at a distance from one another. The gap height and the force to be applied can be adjusted by means of a pretensioning device.

The change position is achieved by corresponding switching of the adjusting elements, here for example by means of a pneumatic pressure medium expandable pressure hose 8 in which the pressure hose 8 is pressurized, the compression spring 15 is loaded and the rigid element 6 deflects to the left, whereby the pressure on the lower terminal strip or clamping rail 5 acting force is withdrawn.

The Figure 6 shows a sectional side view of a further embodiment of the clamping device 2 in the clamping position.

The clamping position is achieved in that the pressure hose 8 is relaxed (emptied) and the compression spring 15 is relaxed. The rigid element 6 pushes the lower terminal strip or clamping rail 5, after the bearing point 5.1 is reached, upwards. Thus, the pressure plate 11 located at the previous distance is now pressed against the clamping surface 3.1 of the upper terminal strip 3 and securely fixed and securely clamped between the upper surface of the clamping rail 5 and the clamping surface 3.1 .

By using an adjustable pressure piece 4 or spring element 7, which form the pretensioning device, it is possible to securely clamp plate-shaped objects on rotationally symmetrical bodies, plate thicknesses of 0.1 to 1 mm, for example, can be clamped with a single clamping device.

List of reference symbols

1 -

Plate cylinder

2 -

Clamping device

3 -

upper terminal strip

3.1 -

Clamping surface

4 -

Thrust pads

5 -

lower terminal strip (clamping rail)

5.1 -

Depository

6 -

rigid element

6.1 -

Depository

7 -

Spring element

8th -

pressure hose

9 -

Compression spring

10 -

Cover strip

11 -

Pressure plate / plate-shaped object

12 -

Cornering

13 -

upper end

14 -

Roller inserts

15 -

Compression spring

Claims (7)

1. Clamping device for fixing printing plates (11) on the plate cylinder (1) of printing presses, having a C-shaped upper clamping bar (3) fixed in a plate cylinder channel, a lower clamping bar (5) that can be moved between a clamping position and a changing position, a switching element which is supported by its upper end section (13) on one underside of the lower clamping bar (5) and by its lower end section on one underside of the C-shaped upper clamping bar (3), and which has at least one adjusting element for engaging the switching element, wherein the switching element is constructed as a flexurally rigid element (6), characterised in that the flexurally rigid element (6) is guided, during the switching operation, by its upper end section (13) sliding on a cam guide (12) located on the underside of the lower clamping bar (5) and which is held at its lower section by a thrust piece (4) arranged in the lower portion of the C-shaped upper clamping strip (3), wherein the thrust piece (4) is provided with a bearing point (6.1) for movably receiving the lower end section of the flexurally rigid element (6), and wherein the pressure piece (4) forms, together with a spring element (7), a prestressing device that helps in pre-setting the gap height between the lower clamping strip (5) and the upper clamping strip (3) as well as the force to be applied when clamping the pressure plates (11).
2. A clamping device according to claim 1, characterised in that only the lower clamping bar or clamping rail (5) is designed to be movable.
3. A clamping device according to claims 1 and 2, characterised in that the lower clamping strip (5) has, on its side facing the interior of the plate cylinder (1), a bearing point (5.1) with a cam guide (12), by which the upper end portion (13) of the flexurally rigid element (6) is received in a slidable manner.
4. A clamping device according to claims 1 to 3,
   characterised in that
   one or more flexurally rigid elements (6) are arranged over the length of the lower clamping strip or clamping rail (5).
5. A clamping device according to claims 1 to 4,
   characterised in that
   the upper clamping strip (3) and/or the lower clamping strip (5) are of a multi-part design whose parts arranged at equal distances from one another over the length of the plate cylinder (1).
6. A clamping device according to claims 1 to 5,
   characterised in that
   the upper end section (13) of the flexurally rigid element (6) is rounded in a semi-circular shape.
7. A clamping device according to claims 1 to 6,
   characterised in that
   the upper end section (13) of the flexurally rigid member (6) is rounded in a semi-circular shape and has roller inserts (14) spaced apart from one another.

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