Device for adjusting translatory moving stops

Abstract

Device for aligning sheets with stops arranged on at least two parallel, translationally moved belts for aligning the sheets at their front edge during sheet transport, wherein the stops (29, 29.1) are arranged to be adjustable in or against the sheet transport direction and each belt (28, 28.1) has a driven deflection roller (31, 31.1), characterized in that the driven deflection rollers (31, 31.1) are translationally displaceable.

Description

This invention relates to a sheet transport apparatus having abutments mounted on translationally moving belts for aligning the sheets at their leading edge during sheet transport.DE 3442135 A1 discloses a device for transporting sheets and aligning the sheet leading edge with stops on the transport path. The sheets are fed to a cylinder of a sheet processing machine, for example a printing machine. The stops are arranged on transport belts which circulate endlessly around two deflection rollers.DE 41 14 479 C1 describes a device for feeding, aligning and holding sheets, which has a strand arrangement which comprises two strands guided over deflection wheels with alignment bridges which connect the strands.DE 10 2007 031 115 A1 describes a device for the positionally accurate feeding of slab-like goods, which device comprises individual runs with alignment stops, which can be mechanically adjustable in order to achieve an exact angular position of the goods with respect to the running direction.U.S. Pat. No. 4,567,824 A describes an apparatus for sheet transport in a printing press, wherein a belt on the drive side of the printing press and a belt on the operator side each run around wheels.The invention is based on the object of providing a device for adjusting the stops in or counter to the sheet transport direction.The object is achieved according to the invention by the features of claim 1.In an advantageous embodiment, it is provided that the deflecting rollers are mounted movably, in particular displaceably, in or counter to the sheet transport direction.In a further development with a tensioning device for the alignment belt, it is provided that only one deflecting roller is arranged so as to be movable, in particular displaceable, in the sheet transport direction, while a tensioning roller engaging on the alignment belt is arranged so as to be deflectable in a spring-loaded manner.In an arrangement with several alignment belts arranged parallel next to each other, it is advantageously provided that each individual driven deflection roller can be driven by means of a common drive shaft.In an alternative solution, it is provided that each of the driven deflection rollers has an individual drive.For adjusting the stops, it is provided that an adjusting device moves the driven deflection roller in translation in its bearing point. A sensor for detecting the stops at a specific machine angle is connected to a control computer and, after evaluation of a setpoint-actual value comparison, supplies a correction signal to a servomotor of the adjusting device.Exemplary embodiments of the invention are illustrated in the drawings and are described below. The following are shown: FIG. 1 shows a sheet-fed rotary printing press in section in schematic illustration, FIG. 2 is a perspective view of an alignment band arrangement, FIG. 3 shows a side view of the alignment belt arrangement in schematic illustration, FIG. 4 shows a side view of the alignment band arrangement with clamping device in schematic view, FIG. 5 shows a perspective view of the alignment belt arrangement with an individual drive for each transport belt in a schematic illustration, FIG. 6 shows a side view of the alignment strip arrangement in schematic representation, FIG. 7 shows a side view of an alternative alignment belt arrangement with a device in schematic view.A machine processing sheets 7, for example a printing machine 1, has a feeder 2, at least one printing unit 3 or 4 and a delivery arm 6. The sheets 7 are removed from a stack of sheets 8 and fed individually or in the form of flakes to the printing units 3 and 4 via a feed table 9. These plate cylinders each contain a plate cylinder 11, 12 in a known manner. The plate cylinders 11 and 12 each have a device 13, 14 for fastening flexible printing plates. Furthermore, each plate cylinder 11, 12 is assigned a device 16, 17 for the semi- or fully automatic printing plate change.The sheet stack 8 rests on a stacking plate 10 which can be lifted in a controlled manner. The sheets 7 are removed from the top side of the sheet stack 8 by means of a so-called suction head 18 which has, inter alia, a number of lifting and suction devices 19, 21 for separating the sheets 7. Furthermore, blowing devices 22 are provided for loosening the upper sheet layers and feeler elements 23 are provided for feeding the stack. For aligning the sheet stack 8, in particular the upper sheets 7 of the sheet stack 8, a number of lateral and rear stops 24 are provided.The feed table 9 has at least one transport belt 26 for transporting the sheets 7 to an alignment unit 27. This consists essentially of at least two parallel alignment belts 28, 28.1, which each carry a stop 29, 29.1, preferably a plurality of stops, for aligning the sheets at their front edge. The conveyor belts 28, 28.1 are continuously deflected around two deflecting rollers 31, 31.1; 32, 32.1. The deflecting rollers 31, 31.1 are driven. In this case, it is provided according to FIG. 2 that each individual driven deflection roller 31, 31.1 is driven by a common drive shaft 33 by means of a belt 34, 34.1.In an embodiment according to FIG. 5, each individual driven deflection roller 31 has an individual drive 36, 36.1.Slippage between the alignment belts 28, 28.1 and the deflection rollers 31, 31.1 and 32, 32.1, respectively, can lead to inaccuracies in the stops 29, 29.1 with respect to the alignment specifications, e.g. a phase offset with respect to the machine angle. For this reason, the stops 29, 29.1 must be adjusted regularly. For this purpose, a sensor 37, 37.1 can be provided for each stop 29, 29.1, which detects the stops 29, 29.1 at a predetermined point in time, in particular at a predetermined machine angle, and feeds them to a control computer, which generates a correction signal after a setpoint-actual value comparison, which correction signal is fed to a servomotor 38, 38.1.The adjusting motor 38, 38.1 is connected to the driven deflecting roller 31 by means of a rod 39 which is displaceable in or counter to the sheet transport direction. The deflecting roller 31 is mounted so as to be horizontally displaceable. The same applies to the deflecting roller 32 which is under the force of a spring element, for example a tension spring 40. When the servomotor 38 is acted upon in rotation, the stop 29 is thus adjusted in or counter to the sheet transport direction via an adjusting gear 42, 42.1, depending on the direction of rotation of the servomotor 38.In an embodiment according to FIG. 4, it is provided that the deflecting roller 32 is arranged in a stationary manner, the driven deflecting roller 31 is arranged in a translatory movable manner, and the transport belt 28 is deflected around a further deflecting roller 41, in particular a spring-loaded tensioning roller 41.List of reference characters1 Printing press 2 Feeder 3 Printing couple 4 Printing couple 5. / . 6 Boom 7 Sheet 8 Sheet stack 9 Feed table 10 Stack plate 11 Plate cylinder 12 Plate cylinder 13 Printing plate mount 14 Printing plate mount 15. / . 16 printing plate changer 17 printing plate changer 18 suction head 19 lifting suckers 20 / . 21 Drag vacuum cleaner 22 Blowing device 23 Sensing element 24 Stop 25. / . 26 Transport belt 27 Alignment unit 28 Alignment belt 28.1 Alignment belt 29 Stop 29.1 Stop 30. / . 31 Deflection roller 31.1 Deflection roller 32 Deflection roller 32.1 Deflection roller 33 Drive roller 33.1 Drive roller 34 Belt 34.1 Belt 35.I. 36 Drive 36.1 Drive 37 Sensor 37.1 Sensor 38 Servomotor 38.1 Servomotor 39 Rod 39.1 Rod 40 Spring 41 Tension roller 42 Adjusting gear 42.1 Adjusting gear

Claims

Device for aligning sheets with stops arranged on at least two belts which are arranged in parallel and are moved in translation for aligning the sheets at their front edge during the sheet transport, wherein the stops (29, 29.1) are arranged so as to be adjustable in or against the sheet transport direction and each belt (28, 28.1) has a driven deflection roller (31, 31.1), characterized in that the driven deflection rollers (31, 31.1) can be displaced in translation.Device according to claim 1, characterised in that the stops (29, 29.1) are arranged on the belts (28, 28.1).Device according to claim 1 or 2, characterised in that all driven deflection rollers (31, 31.1) are in driving connection with a common drive roller (33).Device according to claim 1 or 2, characterised in that each driven deflection roller (31, 31.1) can be driven by means of an individual drive (36, 36.1).Device according to claim 3 or 4, characterised in that the driven deflection rollers (31, 31.1) and freely rotatably mounted deflection rollers (32, 32.1) are mounted in translatory displacement.Device according to claim 5, characterised in that an adjusting device (38, 38.1; 39, 39.1) is provided for translatory displacement of the driven deflection rollers (31, 31.1) in or counter to the transport direction.Device according to claim 6, characterised in that the freely rotatably mounted deflection rollers (32, 32.1) are arranged spring-loaded.Device according to claim 3 or 4, characterised in that the driven deflection rollers (31, 31.1) are mounted so as to be translationally displaceable, that the freely rotatably mounted deflection rollers (32, 32.1) are arranged so as to be stationary and that an additionally spring-loaded tension roller (41) is provided.Device according to one of the preceding claims 1 to 8, characterised in that sensors (37, 37.1) are provided for detecting the stops (29, 29.1), which sensors perform a desired-actual value comparison with respect to a predetermined desired value by means of a control computer and transmit a correction signal resulting therefrom to the actuating device (38).Device according to claim 9, characterised in that the set value signal is a machine angle-dependent signal.Sheet-fed rotary printing press having an apparatus according to one of the preceding Claims 1 to 10.

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