The invention relates to a delivery for a machine for processing flat printing materials, in particular a sheet-processing rotary printing press, having sheet brakes which accept, at an acceptance level, a sheet fed in a processing direction, and which release the sheet at a surrender or release level, and also to a machine for processing flat printing materials, which is equipped with such a delivery, in particular a sheet-processing rotary printing press.
Sheet brakes in machines for processing flat printing materials, such as sheet-processing rotary printing presses, in particular, serve for slowing down the processed printing materials from a processing speed to a depositing speed, and operate on the principle that braking elements penetrated by vacuum, which are moved at a suitably low speed, attract by suction printing materials released above the braking elements by a transport device, in particular in the form of revolving gripper systems dragging the printing materials in a direction towards the sheet brakes, and after the printing materials have been braked to a depositing speed, in turn, release the printing materials, so that the thus braked printing materials then move freely in a direction towards leading edge stops which are provided for forming a sheet pile and which assume one and the same position for all the formats of the printing materials processed by the machine. In order to keep the free path covered by the printing materials released by the braking elements as short as possible, the sheet brakes are displaced downstream with respect to the processing direction in order to adapt to a respectively smaller format of the processed printing materials, and are set to a respective position matched to the format. Sheet brakes operating and positionable in this way are disclosed, for example, by German Patent DE 44 24 483 C2, corresponding to U.S. Pat. No. 5,568,919.
In order to grip and suck the printing materials reliably against the braking elements, it is advantageous to place the latter as close as possible to the path swept by the gripper systems, because the vacuum that acts through the braking elements develops an adequate suction action only when there are small distances between the braking elements and the printing materials. Such placement of the braking elements, i.e., of the sheet brakes, is disadvantageous, however, in particular when there is a relatively long overlap, on the one hand, of printing materials attracted to the braking elements by suction and already retarded and, on the other hand, of printing materials continuing to be dragged by the gripper systems, such as is the case, in particular, when processing large-format printing materials, and can result in smearing of the printed image and, in particular, to turning over or so-called dog-earing of trailing corners of the printing materials.
Therefore, the reliable braking of the printing materials, on the one hand, and the ensuring of satisfactory printed products, on the other hand, place conflicting requirements on the method step of braking printing materials.
It is accordingly an object of the invention to satisfy the conflicting requirements explained hereinbefore, i.e., of achieving reliable braking while ensuring satisfactory printing quality. More specifically, it is an object of the invention to provide a delivery for a machine for processing flat printing materials which satisfies the foregoing requirements.
With the foregoing and other objects in view, there is provided, in accordance with an aspect of the invention, a delivery for a machine for processing flat printing materials, comprising sheet brakes for accepting sheets fed in a processing direction at an acceptance level and for releasing the sheets at a surrender or release level, the sheet brakes being adjustably disposed for varying the acceptance level and the surrender or release level.
In accordance with another aspect of the invention, there is provided a delivery for a sheet-processing rotary printing press, comprising sheet brakes for accepting sheets fed in a processing direction at an acceptance level and for releasing the sheets at a surrender or release level, the sheet brakes being adjustably disposed for varying the acceptance level and the surrender or release level.
In accordance with a further feature of the invention, the sheet brakes have a translatorily adjustable arrangement.
In accordance with an added feature of the invention, the delivery further comprises a guide arranged for rising downstream with respect to the processing direction and along which the sheet brakes are adjustable in the processing direction and counter thereto.
In accordance with an additional feature of the invention, the delivery further comprises a guide oriented in the processing direction, the sheet brakes being adjustable in height.
In accordance with yet another feature of the invention, the guide is adjustable in height.
In accordance with yet a further feature of the invention, the sheet brakes are adjustable in height with respect to the guide.
In accordance with yet an added feature of the invention, the sheet brakes are rotationally adjustable for varying the surrender or release level.
In accordance with yet an additional feature of the invention, the sheet brakes comprise suction belts for forming braking strands, the suction belts being endless and being revolvable during operation, the rotational adjustability of the suction belts serving for setting to different levels a respective end of the braking strands disposed downstream with respect to the processing direction.
In accordance with a concomitant aspect of the invention, there is provided a machine for processing flat printing materials, having a delivery, comprising sheet brakes for accepting sheets fed in a processing direction at an acceptance level and for releasing the sheets at a surrender level, the sheet brakes being adjustably disposed for varying the acceptance level and the surrender level.
In order to achieve the foregoing objects, the delivery referred to at the introduction hereto is developed with sheet brakes arranged so as to be adjustable in a manner that the acceptance level and the surrender or release level are variable.
This provides the option of adapting the acceptance level and the release level both to the format of the processed sheets and also to the grammage and the stiffness thereof.
To this end, during the processing of the printing materials having the largest processable format, the acceptance level and the release level are preferably set lower than when processing the printing materials having the smallest processable format.
Positioning the sheet brakes at a lower level when processing the largest-format printing materials complies with the behavior of these printing materials being dragged by a respective gripper system, in that the trailing end section thereof moves on a path which lies considerably below the path of the respectively leading gripper edge of these printing materials clamped in the respective gripper system, so that the result of this has also no disadvantageous effect upon the reliable attraction of these printing materials by suction to the braking elements of the sheet brakes.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a delivery for a machine for processing flat printing materials, it is nevertheless not intended to be is limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
a is a view of the sheet brake of
a is a view of the sheet brake of
Referring now to the drawings and, first, particularly to
Along the paths between the drive sprockets 7, on the one hand, and the guide or reversing sprockets 8, on the other hand, the conveyor chains 6 are guided by chain guide rails, which therefore determine the chain paths of the chain strands or runs. In the example of
In order to prevent mutual sticking or adhesion of the printed sheets 3 in the sheet pile 14, a dryer 19 and a powdering device 20 are provided on the path of the sheets 3 from the drive sprockets 7 to the braking station 11.
In order to avoid excessive heating of the sheet guide surface 17 by the dryer 19, a coolant circuit, which is represented symbolically in
The sheet brakes 11.1 are constructed, for example, as suction belt brakes having endless suction belts 11.2 which run over rollers 11.2′ during operation. They are lined up in a row transversely with respect to the processing direction at mutual intervals which, in a preferred configuration not specifically illustrated here, can be varied in such a way that the suction belts 11.2 can be set to print-free corridors on the printed underside of the sheets 3 during a verso or perfector printing operation of the rotary printing press.
Depending upon the print job, the sheets 3 can have different formats, which extend from a largest format that can yet be processed to a smallest format that is yet tolerable for economic operation.
As can be seen from
In order to adjust the sheet brakes 11.1 along a guide 25 comprising the guide rails 25.1 and 25.2, the braking carriage 24 carrying the sheet brakes 11.1 is inserted into a chain of a chain drive 26. By appropriately driving a motor 26.1 (note
The guide 25 and the chain drive 26 form a structural unit which can be adjusted vertically by suitable actuating members and which, in the illustrated example, further comprises vertical guide shafts 27 which are connected to the guide 25 and which engage slidingly in guide bores 28 machined in guide elements 29 which, for their part, are rigidly connected to a respective side wall of the delivery or can also be formed integrally with a respective side wall.
On a side of the guide 25 facing away from the guide shafts 27, i.e., the underside in the example of
By appropriate control of the motor 31.1, the guide 25 can be set to positions between a first level and a second level, higher with respect to the first level, the maximum vertical difference between the second and the first level being presented in
Compression springs 32 braced at one end thereof against the guide elements 29 and at the other end thereof against the guide 25 prestress the guide 25 in the direction of the lower, first level and ensure the maintenance of contact between the guide and the eccentrics 30. The eccentric shafts 30.1 are mounted in fixed locations in a conventional manner not otherwise specifically illustrated and therefore, with appropriate rotation thereof, permit the setting of the sheet brakes 11.1 to positions between a first level and a second level disposed higher with respect to the first level. Instead of the eccentrics 30, other types of control cams can, of course, also be used.
In
In the configuration according to
In
The braking carriage 24″ comprises a moving frame 24″.1 bearing the runner rollers 24.1 and having an outline which forms a rectangle, at least approximately. In the moving frame 24″.1, for example, in the region of a respective corner of the rectangle, vertical threaded spindles 24″.2 are mounted and secured against axial displacement. The threaded spindles 24″.2 engage in threaded boreholes 24″.3 formed in a holder 2″.4 that carries the sheet brakes 11.1 and can therefore be raised and lowered by respective synchronous rotation of the threaded spindles 24″.2, so that the sheet brakes 11.1 can be adjusted vertically with respect to the guide rails 25.1 and 25.2 forming the guide and can be set to positions between a first level and a second level, which is higher with respect to the first level.
In order to drive the threaded spindles 24″.2, a toothed belt drive 24″.5 is provided in the exemplary embodiment of FIG. 4. To this end, the threaded spindles 24″.2 are provided with a respective toothed belt pulley 24″.6 fixed to the spindles 24″.2 so as to rotate therewith. The toothed belt pulleys 24″.6 have a toothed belt 24″.7 looped around them, and one of the threaded spindles 24″.2 is drivable by a reversible motor 24″.8 via a bevel gear mechanism 24″.9, the motor 24″.8 bearing a driving bevel gear flange-mounted to the moving frame 24″.1.
In the various configurations described hereinbefore, the suction belts 11.2 which revolve during operation are guided and arranged with regard to the respective braking carriage 24, 24′, 24″ in such a way that they form braking runs or strands 11.3 which extend horizontally, accept a respective sheet 3 by attracting the latter by suction and release the respective sheet 3 after it has been braked.
In the event of an arrangement of the sheet brakes 11.1 on the respective braking carriage 24, 24′, 24″ provided in such a way that the orientation of the braking runs or strands 11.3 is basically horizontal, the sheets 3 are accepted and released at one and the same level, but this can be varied to adapt to parameters of the sheets, such as, in particular, the format, grammage or stiffness. A change in the acceptance level and in the surrender level coinciding therewith is, in this case, performed translatorily.
In
In
In order to adjust the rotational position of the crank in the configurations according to
In
In a preferred refinement of the invention, the sheet brakes 11.1 and 11.1′, respectively, following one another transversely to the processing direction can be set individually to different level differences. A wavy course transverse to the processing direction can therefore be forced on the sheet and, thus, stiffening of the sheets in the processing direction can be achieved.
In an advantageous development, the rotational adjustment of the sheet brakes is performed by a control device 11.6 at the cyclic rate of the sheet sequence, so that a braking strand gripping the sheets in order to transfer the respective sheet is at least approximately equidistant from the path through which the gripper systems which drag the sheets have passed and, after a respective sheet has been transferred, the downstream end of the braking strand is lowered.
In the instantaneous setting or position of the control cam disk 11.6″″ illustrated in
One advantageous use of the subject of the invention provides for the highest possible acceptance level N1, with which the surrender or release level preferably coincides, for stiff sheets of small format, in particular, and for the lowest possible acceptance level N1 to be provided for large-format and in particular floppy sheets and, preferably, for a surrender or release level N2 lower than the acceptance level N1 to be set, moreover recourse preferably being had to sheet brakes forming braking strands by suction belts, which attract the sheets by suction onto the braking strands until the sheets are close to the downstream end thereof.
Number | Date | Country | Kind |
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101 36 744 | Jul 2001 | DE | national |
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27 20 674 | Nov 1978 | DE |
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Number | Date | Country | |
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20030019378 A1 | Jan 2003 | US |