Abstract:
A device for fixing a flexible plate having angled or beveled suspension edges to a cylinder utilizes a plurality of fastening elements located in a cylinder groove situated radially inwardly of a fastening slit. The fastening elements are engageable with the suspension legs under the influence of spring forces. Separate fastening elements can be used to engage the leading plate suspension leg depending on the direction of rotation of the cylinder.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to devices for fixing a flexible plate on a cylinder of a rotary printing press. The flexible plate has suspension legs which fit into a cylinder groove. Several fastening elements for the suspension legs are positioned in the cylinder groove. One of the suspension leg fastening elements may include a jamming roller. 
     DESCRIPTION OF THE PRIOR ART 
     A device for fixing a flexible printing plate on the forme cylinder of a rotary printing press having at least one cylinder groove extending in the axial direction is known from DE 43 35 140 C1. 
     A first, or leading suspension leg, which is beveled at an acute angle, is suspended at an edge of the first groove wall of the cylinder groove of the forme cylinder. A second, or trailing, suspension leg can be placed against the second groove wall, which second groove wall is extending approximately in the radial direction of the forme cylinder, of the cylinder groove. The cylinder groove contains a spindle which is pivotable around its axis. Two leaf springs, each of which is distributed over the width of the printing plate, are fastened on the spindle and can be brought into, or out of contact with the suspension legs in the course of pivoting the spindle. 
     DE 196 36 412 C1 discloses a cylinder on which pressure cams for clamping both suspension legs of a printing plate are arranged on a pivotable shaft. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is directed to providing a device for fixing a flexible plate on a cylinder of a rotary printing press. 
     In accordance with the present invention, this object is attained by providing the plate receiving cylinder with a cylinder groove which is accessed through a fastening slit. Suspension legs of the flexible plate are received in the fastening slit where they are engaged by fastening elements. One of the suspension legs can be fastened against an abutment in the cylinder groove wall by one of the fastening elements. Another of the fastening elements is a pivotable flap with a jamming roller arranged between the flap and one of the plate suspension legs. 
     The advantages to be obtained by the present invention consist, in particular, in that a rugged, simply constructed device is created, which can be produced cost-effectively. The device in accordance with the present invention can be displaced without the turning of a spindle in only two positions. A further advantage of the present invention lies in that in its axial extension it can consist of several short base bodies. It is possible because of this to remove the device laterally piece by piece from the cylinder groove, for example for maintenance purposes, without having to dismount the cylinder from the lateral frame. It is of particular advantage that the device can also be employed in case of a reversal of the direction of rotation of the cylinder supporting the plates, for example in connection with satellite printing units. An automatic plate feeding and removal by the use of known devices is possible. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred embodiment of the present invention is represented in the drawings and will be described in greater detail in what follows. 
     Shown are in: 
       
     FIG. 1, a sectional view, taken along line I—I of FIG. 4, with the cylinder, the plate and the air hose in a plate-holding or rest position and in an enlarged scale, 
     FIG. 2, a sectional view taken along line II—II of FIG. 4, with the cylinder, the plate and the air hose in an enlarged scale, 
     FIG. 3, a sectional view analogous to FIG. 1, with the device in a plate-removing or operating position, and in 
     FIG. 4, a view from above on the device, without the cylinder and without the air hose in a partial enlarged representation and limited in the axial direction. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For receiving flexible plates  02 , a cylinder  01 , for example a plate or rubber blanket cylinder of a rotary printing press, is provided with at least one cylinder groove  03  extending in the axial direction. At a front edge  04 , pointing in the production direction A of the cylinder  01 , which cylinder  01  turns toward the right, or in a clockwise direction of rotation, the cylinder groove  03  will receive a front, or “leading”, beveled suspension leg  06  of the plate  02  with an opening angle α. The plate  02  furthermore has a rear, or “trailing” beveled suspension leg  07 , which is suspended from a second, rear edge  08  of the same cylinder groove  03  and which has an approximately right opening angle β, all as may be seen in FIG.  1 . 
     It is also possible to arrange two plates, for example two printing plates, on the circumference of the cylinder  01 . In this case, two diametrically opposing cylinder grooves are required in the circumferential direction of the cylinder  01 . 
     An acute opening angle α, for example of up to 45°, is formed between the surface  11  of the cylinder  01  and a first cylinder wall  12  of the cylinder groove  03 . A second cylinder groove wall  13  also has an acute opening angle α in respect to a peripheral or circumferential surface  11  of cylinder  01 . Both edges  04 ,  08 , which are also vertex points of the opening angles α, are separated by, and define a fastening slit  09 . 
     It is possible to also suspend a plate  23  by its suspension legs  24 ,  26  on the cylinder  01  in such a way that its “leading”, acute-angled suspension leg  24  is suspended at the edge  08 , and its “trailing”, approximately right-angled suspension leg  26  is suspended at the edge  04 , as seen in FIG.  2 . Therefore the “leading” suspension leg  24  points in the production direction B toward the left, i.e. in a counterclockwise direction of rotation. 
     The fastening slit  09  is embodied so that its inner width f is sufficient such that at least two suspension legs  06 ,  07 , which project into the cylinder groove  03 , can be placed therein next to each other. 
     In place of a printing plate or several printing plates placed next to each other, it is possible to also fasten flexible support plates with rubber blankets arranged on them on cylinder  01 . 
     The cylinder groove  03  can be approximately circular in cross section and is connected with the cylinder surface  11  through the fastening slit  09 . 
     A base body  14 , which is open in the direction toward the fastening slit  09 , is arranged in the cylinder groove  03  and has, for example, a cross section in the form of a longitudinally cut tube so that it is channel-shaped. In accordance with an embodiment represented in FIG.  1  and also in FIG. 4, this base body  14  can consist, in the axial direction, of several short base bodies  16 ,  17 ,  18 , which can be coupled with each other. Only three such short base bodies are represented in FIG.  4 . Such a coupling of the short base bodies can act interlockingly, for example, and can be implemented by sets of teeth  19 ,  21  on both ends of the short base bodies  16 ,  17 ,  18 . The two outer sets of teeth  19 ,  21  can be fixed in place at the cylinder end faces by the provision an end coupling element, not specifically represented. 
     A number of different clamping and/or jamming elements C, D, E are arranged in the interior  22  of each base body  14 , or  16  to  18 , such as shown by the example of the base body  17  in FIG. 4, and as described, as follows: 
     first clamping and/or jamming elements C for the “trailing” suspension leg  07 ,  26 , which “trailing” suspension leg has an approximately right-angled opening angle β, 
     second clamping and/or jamming elements D for a suspension leg  06 , which is beveled at an acute angle α and is “leading” in the production direction A toward the right, as seen in FIG. 1, 
     third clamping and/or jamming elements E for a suspension leg  24 , which is beveled at an acute angle and is “leading” in the production direction B toward the left, as seen in FIG.  2 . 
     The channel-shaped base body  14 , or the short base bodies  16  to  18 , can be embodied to be C-shaped, U-shaped, round, oval or polygonal in cross section. The cross section of the cylinder groove  03  is matched to the respective cross section of the base body  14 , or short base bodies  16  to  18 . 
     The cross section of the base body  14 , or short base bodies  16  to  18  represented in FIGS. 1 and 2 is embodied in a C-shape. One of its openings points approximately in the direction of the fastening slit  09 . The above described clamping and/or jamming elements, which are arranged so that they can be brought into or out of operating connection with the suspension legs  6 ,  7 , or  24 ,  28 , project through the opening facing slit  09 . 
     The first clamping and/or jamming elements C consist of a first flap  27 , which is pivotably seated in the base body  14  or  16  to  18  and whose longitudinal axis extends in an axis-parallel direction, and whose vertical axis extends in the radial direction in respect to the cylinder  01 . A lower end  28  of the first flap  27 , which is remote from the cylinder surface, enters into a slit  29  of the respective base body  14 , or  16  to  18 , and in this way forms a pivot bearing. 
     The first flap  27  has an axial length l, as seen in FIG. 4, which corresponds approximately to one-third of the total axial length of a base body  16 ,  17  or  18 . An upper end  31  of the first flap  27 , which is close to the cylinder surface, has a cutout  32 , which is bounded on both sides by a respective arm  33 ,  34 . Each arm  33 ,  34  has an axial length m with a jamming surface  36 ,  37 . The axial length m corresponds approximately to one-fourth of the total axial length l of the flap  27 . Each of the jamming surfaces  36 ,  37  is in an operational connection with a respective jamming surface of an abutment  38 ,  39  of the base body  14 , or of the respective short base bodies  16  to  18 , as shown in FIGS. 1 and 4. The jamming surfaces of the abutment  38 ,  39  are located, in the radial direction, below the fastening slit  09 . As represented in FIGS. 2,  3 , the arms  33 ,  34  of the flap  27  can be bent off, approximately at right angles, pointing in the direction of the abutment  38 ,  39 . 
     The pivotable first flap  27  can be brought from a plate-holding position into a plate-removing position against the force of a spring  41 , for example a compression spring fixed in place on the base body. 
     Actuation of the pivotable first flap  27  takes place by operation of an inflatable air hose  42 , which will be described in detail later. 
     The second clamping and/or jamming elements D for a beveled suspension leg  06  of the plate  02  “leading” toward the right in the production direction A consist of a second flap  43 , which is pivotably seated in the base body  14  or short base bodies  16  to  18  and extends, spaced at a distance by the air hose  42 , parallel with the flap  27 , as seen in FIG. 1. A lower side  44  of this second flap  43  enters into a slit  46  of the respective base body  14 , or the short base bodies  16 , or  18 , and constitutes a pivot bearing. 
     The second flap  43  has an axial length of n, as shown in FIG.  4 . This axial length approximately corresponds to the length of the cutout  32 , and to twice the axial length m. 
     The top  47  of the second flap  43 , which is near the cylinder surface, is bent at approximately right angles in the direction toward the first groove wall  12 , and its edge  49  projects into the cutout  32  of the flap  27  located between the arms  33 ,  34 . A roller body, for example a jamming roller  48 , is maintained in the cutout  32 , and will be pressed against the “leading” suspension leg  06  resting against the first groove wall  12 , by the edge  49  of the flap  43  in response to the force of a spring  51 , for example a compression spring fixed in place on the base body. 
     Release or disengagement of the pivotable second flap  43  takes place by inflation of the inflatable air hose  42  located between the two flaps  27 ,  43 , which can pivot, i.e. open, both flaps  27 ,  43  against the force of the springs  41 ,  51 . 
     The third clamping and/or jamming elements E for a beveled suspension leg  06  of the plate  23  “leading” toward the left in the production direction B, as seen in FIG. 2, consist of a third flap  52 , which is pivotably seated in the base body  14  or short base bodies  16  to  18  and is of a length l. A fourth flap  53  of equal length extends parallel with the third flap  52  and is kept at a distance by the air hose  42 . Both flaps  52 ,  53  are respectively seated at their lower ends  54 ,  56 , i.e. their ends remote from the cylinder surface  11 , in a slit  57 ,  58  of the respective base body  14 , or short base bodies  16  to  18 , and can be actuated by the force of springs  59 ,  61 , for example compression springs, as shown in FIG.  2 . 
     By its jamming surface or edge  63  extending in the axial direction, a top  62  of the third flap  52  is indirectly, i.e. with the interposition of a jamming roller  64 , in an operative connection with the second groove wall  13 , or with a “leading” suspension leg  24  of the plate  23 , resting against the second groove wall  13 . Here, the edge  63  of the top  62  of the third flap  52  is bent at approximately right angles, pointing in the direction of the second groove wall  13 . The jamming roller  64  is supported by an upper lateral face  66  of the fourth flap  53 . The base body  14  or the short base bodies  16  to  18  has a cutout  67  in the area of the jamming roller  64 . 
     The clamping and/or jamming elements C, D, E are arranged in an axial length of each short base body  16  to  18 , and therefore also in the one-piece base body  14 , in such a way that the length of a short base body  16 ,  17  or  18  of  3  l corresponds to a number of lengths l, m, n of the clamping and/or jamming elements as seen in FIG.  4  and as follows: 
     
       
         3  l= 4  m  for  C+ 2  n  for  D+l  for  E   
       
     
     The clamping and/or jamming elements C for the “trailing” suspension leg  07  or  26  are used with each jamming of the plates  02  or  23 . When using a plate  02  and the direction of rotation A of the cylinder  01 , the clamping and/or jamming elements D for the “leading” suspension leg  06  are additionally put into operation. But if a plate  23  is used when the cylinder  01  turns in the direction of rotation B, the clamping and/or jamming elements E are employed in place of the clamping and/or jamming elements D. 
     The base body  14 , or the short base bodies  16  to  18 , are preferably arranged in a manner fixed against relative rotation in the cylinder groove  03 . 
     The inflatable air hose  42  extends, in one piece, over the entire length of the cylinder groove  03 . On one of its ends, the air hose  42  is provided with a valve, for example, and is charged with compressed air when needed via a connection line, not specifically represented, to the cylinder journal, and by means of a known rotary lead-in. 
     If the device is intended to be brought from the plate holding position or position of rest, as depicted in FIG. 1 into the plate-removing, or operating position, as depicted in FIG. 3, the air hose  42  is charged with compressed air at a pressure of approximately six bar. The plates or flaps  27 ,  43  and  52 ,  53  are pivoted away from each other against the force of the springs  41 ,  51  and  59 ,  61 . In the course of this, the suspension legs  06 ,  07 , or  24 ,  26 , are released as depicted in FIG.  3 . 
     In accordance with a preferred embodiment, the force of the pressure of each spring  51 , as well as each spring  59 ,  61 , is respectively greater than the force of the pressure of the spring  41 . Initially, the air hose  42  is charged with an air pressure of approximately three bar. Therefore the force of the pressure exerted by the air hose  42  is greater than the force of the pressure of the spring  41  and less than the force of the pressure of the springs  41 ,  59  or  61 . The first flap  27  shown in FIGS. 1 and 3 is pivoted and the jamming surfaces  36 ,  37  come out of contact with the rear suspension leg  07 , or  26 . The “trailing” end can snap out of the fastening slit  09  because of the inherent tension of the plate  02 , or  23  with its suspension leg  07  or  26  and can thereafter be grasped. 
     The result of increasing the air pressure in the air hose  42  to approximately six bar is that the force of the pressure exerted by the air hose  42  now is also greater than the force of the pressure of the springs  41 ,  59  or  61 , so that the suspension leg  06 , or  24 , is also released. 
     While a preferred embodiment of a device for fixing a flexible plate, in accordance with the present invention, has been described fully and completely hereinabove, it will be apparent to one of skill in the art that a number of changes in, for example, the overall size of the cylinder, the specific type of flexible plates secured to the cylinder, and the like could be made without departing from the true spirit and scope of the present invention which is to be limited only by the following claims.