Patent Application
20060288892
The invention relates to a method and a device for rapidly transporting sheets to a sheet-processing machine, especially a printing press, wherein the sheets are transversely and obliquely aligned on a transport path in and opposite to a sheet transporting direction.
The state of the art according to European Patent EP 10 44 908 B1, corresponding to U.S. Pat. No. 6,378,862 B1, discloses such a device, in particular for transporting plate-shaped objects to a punch. That device is formed basically of a reciprocatingly driven base carrier having a mechanical holding device, which is adjustable by actuators with respect to a base carrier in a transport plane. The adjustment occurs based upon position sensors, which grip the sheet edge and, upon deviation from a precalculated (desired) position, transmit control signals to the actuators, which control the holding device in such a manner that the sheets, respectively, in and opposite to the transport direction of the base carrier, can be aligned transversely and obliquely thereto. The holding device per se is formed of a format-wide clamping bar, which cooperates with a plate support.
The plates so-to-speak are fed from behind to the holding device and during the transfer to a conveyor device passed in stand-by position through the clamping gap.
That device is suitable, preferably, for low feeding or supplying speeds.
It is accordingly an object of the invention to provide a method and a device for transporting or accelerating sheets to a sheet processing machine, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known methods and devices of this general type and which are suitable especially for high feeding or high supplying speeds.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method of transporting sheets and feeding sheets to a sheet processing machine. The method comprises gripping a sheet, moving in a transport direction, with a gripper device having a gripper bite and detecting a position of the sheet while in the gripper bite. Upon a deviation of an actual position from a desired position of the sheet, during a transport movement of the sheet to a moving advancing device, the sheet is aligned in or counter to the transport direction obliquely and transversely to the transport direction. This occurs by aligning the sheet in or counter to the transport direction by a simultaneous acceleration or deceleration of a driven carrier in parallel movement paths, carrying out oblique alignment with a different drive of the carrier in the movement paths, and carrying out lateral alignment with a lateral shifting of the gripper device.
With the objects of the invention in view, there is also provided a device for carrying out the method of transporting sheets and feeding sheets to a sheet processing machine. The device comprises a device disposed on the transport path for detecting a position of the sheet and for aligning the sheet. A gripper device is guided in the movement paths. The gripper device is drivable on each movement path independently of the other movement path, and the gripper device is mounted for lateral displaceable relative to the movement paths.
It is a particular advantage of the method that the sheets, after a separation from a sheet pile, or produced by a cross-cutter, can be fed continuously, without stopping, to an operating station, preferably a printing unit of a printing machine. Due to these measures, the feeding or supplying speed can be increased and thus be adapted to currently possible printing speeds.
A particular advantage of the invention is the simultaneous or independent control of a carrier for the gripper device, which is guided in parallel rails. Due to this measure, a sheet held in the gripper direction, with simultaneous control of a linear motor which is provided, can be accelerated in sheet transport direction in order, for example, to accelerate the sheet to the speed of the conveyor system and, in addition thereto, correct late sheets.
Furthermore, due to the reduction in the normal acceleration, early sheets can be corrected. An independent control results in an offset or crossing movement of the carrier and serves for correction of misaligned or out-of-square sheets. A possibility for laterally adjusting the gripper device with respect to the carrier serves for the lateral alignment, preferably with the aid of a parallelogram-type adjusting device.
A simple structure is represented, for example having a mechanical control roller-cam device. The respective gripper opening and closing movements preferably occur by a mechanical control. Alternatively, however, a suction gripper device is also advantageous. Further inventive developments or refinements, such as a squared-off or angular adjustment of the feeding device with respect to the conveyor device for the purpose of adjusting the sheet thickness, are described below.
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 method and a device for transporting sheets to a sheet processing machine, it is nevertheless not intended to be 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.
Referring now to the figures of the drawings in detail and first, particularly, to
The sheet pile 8 lies on a controllingly liftable pile board 10. Removal of the sheets 7 is effected from the upper side of the sheet pile 8 by a so-called suction head 18 which, among other things, has a number of lifting and pulling suckers 19, 21 for the singling of the sheets 7.
Furthermore, blast devices 22 for loosening up the upper sheet layers, and sensing elements 23 for pile follow-up, are provided. A number of side and rear stops 24 are provided for alignment or registration of the sheet pile 8, especially the upper sheets 7 of the sheet pile 8.
In order to transfer the sheet 7 from a shingle stream or a stream of consecutively transported sheets 7 (single sheet transport) to a cylinder 26 of the printing press, for example a feed cylinder 26, the sheet feeding or transport and accelerating system 27 is disposed between the feed table 9 and the feed cylinder 26. The feed cylinder 26 may also be referred to as an advancing device.
As is seen in
As is seen in
A rotatably mounted control roller 44, which is provided on the gripper bridge 38, cooperates with an adjustably disposed control cam, preferably in the form of a guide rail 46. The guide rail 46 is stationarily disposed parallel to the sheet transport direction and, with the aid of an actuator 47, for example a linear motor or an actuating drive, is adjustably mounted transversely to the sheet transport direction. A spring-loaded counter-roller 49 which is provided opposite to the control roller 44, has an accumulator 51 being braced against an abutment 52 that is fastened to the gripper bridge 38. The guide rail 46 is always located between the control roller 44 and the counter-roller 49.
The actuator 47 is connected to a control computer 54 of the sheet-processing machine and, when the lateral position of the sheet deviates, performs correction movements, which result in the guide rail 46 being shifted transversely to the sheet transport direction. This shift, due to the contact of the control roller 44 with the guides 46, causes the gripper bridge 38 and therewith also the sheet 7 held in the grippers 39, to perform a lateral correction movement. The guide rail 46 extends over the entire transport path from the feeder table 9 to the conveyor device or feeding cylinder 26. Through the use of this measure, a large time window is made available for the alignment or adjustment of the sheets.
As is seen in
When a misaligned sheet is recognized, a suitable independent control of the drives having the rails 28, 31 occurs.
The correction movements of the gripper bridge 38 and, therewith, of the sheet 7, are concluded up to the transfer to the rotating feed cylinder 26, so that the sheet 7 can be surrendered in alignment, without it being stopped on the transport path to the first operating station, for example the printing unit 3.
As is seen in
The entire transport and alignment path, length or stretch is disposed in a frame or stand 68 shown in
In order to transport the sheets in register from the feeder pile or a non-illustrated cross-cutter into the processing station of the sheet processing machine, especially a printing press, they are fed by the feed table 9 individually in succession or preferably shingle-like to the grippers 39 of the gripper bridge 38, which grips the respectively leading or front sheet 7 out of the moving overlapping or shingle stream. In the gripper bite or closure, the sheet position is determined by the sensors 55 to 57 that are respectively disposed preferably over and above the conveyor path, stretch or length, and suitable correction movements are introduced, if necessary or desirable, on the path to the feed cylinder 26, so that the sheet can be transferred in register to the rotating feed cylinder 26, without mechanical aligning aids and without stopping.
As an alternative to a mechanical gripper bite or closure of the sheet by grippers disposed on a gripper bridge, it is naturally also possible to subject the gripper bridge 38 to suction air or to provide suction grippers 72 shown in
This application claims the priority, under 35 U.S.C. ยง119, of German application DE 10 2005 029 931.8, filed Jun. 28, 2005; the prior application is herewith incorporated by reference in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 029 931.8 | Jun 2005 | DE | national |
