Device for aligning a bow

Abstract

Device for aligning a sheet by means of an alignment roller arranged transversely to the sheet transport direction, which has two independently driveable drives, characterized by that the alignment roller has three drive wheels (38, 39, 41) arranged apart from each other, that the outer drive wheels (38, 39) can be driven directly by the drives (28, 29) assigned to them and that the middle drive wheel (41) can be driven by the drives (28, 29) by means of a differential gear (47).

Description

[0001] The invention relates to an alignment roller for aligning a sheet.

[0002] US 8,066,282 B2 discloses a device for skewing sheets using conveyor belts.

[0003] EP 0469866 M1 discloses a sheet alignment device in which two spaced-apart drive rollers each interact with a counter roller, and each drive roller has a drive motor that can be controlled independently of the other drive roller. For skew alignment of a sheet, the drive rollers can be driven at different speeds. For lateral alignment, the drive rollers are arranged so they can be moved laterally.

[0004] During transport and alignment of particularly large sheet formats, the problem arises that great pressure is exerted on the sheet to be aligned in the area of ​​the alignment rollers.

[0005] JP 2008 - 239 295 A describes a media conveying device in which an alignment roller is arranged for different formats.

[0006] The invention is therefore based on the object of creating a device for aligning sheets in which the pressure exerted on the sheet is minimized.

[0007] The object is achieved according to the invention by a device having the features of claim 1.

[0008] The object is also achieved according to the invention by a device having the features of claim 2.

[0009] The object is also achieved according to the invention by a device having the features of claim 3.

[0010] In one embodiment, the number of drive wheels transverse to the sheet transport direction is increased, i.e., at least three, to minimize the pressure exerted by the drive wheels on the sheet. The inner drive wheels, located between the individually driven outer drive wheels, are driven by at least one differential gear. This measure drives the inner drive wheels, depending on their position, at an "average" peripheral speed relative to the outer drive wheels. Various embodiments are illustrated in the drawings and are described below. They show: Fig. 1 a feeder for a sheet processing machine in schematic representation, Fig. 2a a plan view of a twistable alignment roller with two drive motors in a device not according to the invention, Fig. 2b a top view of the alignment roller in twisted state, Fig. 3a the alignment roller with a continuous surface in a perspective view, Fig. 3b the alignment roller in twisted state in a perspective view, Fig. 4a the alignment roller with a surface consisting of spaced rings in a further device not according to the invention, Fig. 4b the alignment roller Fig. 4a in twisted state in perspective view, Fig. 5 an embodiment of an alignment roller according to the invention with three drive wheels, Fig. 6 shows a further embodiment of an alignment roller with four drive wheels according to the invention, Fig. 7 shows a further embodiment of an alignment roller with five drive wheels according to the invention.

[0011] In Fig. Figure 1 shows the basic structure of a sheet punching and / or embossing machine 100 for punching, stripping, blanking, and depositing sheets of paper, cardboard, plastic, and the like. The punching and / or embossing machine 100 has a feeder 1, a punching station 2, a stripping station 3, and a delivery 4 with a deposit and blanking station, which are supported and enclosed by a common machine housing 5 and driven by a main drive 17. The processing stations 2, 3, and 4 are accessible from one side, the so-called operator side; the drive train of the sheet punching and / or embossing machine 100 is located on the opposite side, the so-called drive side. A machine control system 15 controls the processes within the machine 100.

[0012] The sheets 6 are separated from a stack 19 in the feeder 1 by means of a so-called suction head 18 and fed to the sheet transport system 7 via a feed table 16. The sheet transport system 7 has grippers attached to gripper bridges of a gripper carriage 8, which grip the sheet 6 at its leading edge and intermittently guide it in the sheet transport direction B through the various stations 2, 3, and 4 of the punching and embossing machine 100.

[0013] The sheet transport system 7 has several gripper carriages 8, so that several sheets 6 can be processed simultaneously in the various stations 2, 3, and 4. The gripper carriages 8 can be driven by a chain drive or, in an alternative embodiment, by an electromagnetic linear drive with traveling-wave motors, as described, for example, in DE 20 2007 012 349 U1.

[0014] The punching station 2 consists of a lower platen, a so-called lower table 9, and an upper platen, a so-called upper table 10. The upper table 10 is mounted vertically for reciprocating movement and is equipped with an upper tool 30 with punching and creasing knives. The lower table 9 is fixedly mounted in the machine frame and is provided with a counterplate 20 for the punching and creasing knives. Alternatively, the upper table 10 can be stationary and the lower table 9 can be movable. During embossing, embossing tools, particularly in the form of embossing clichés, are used instead of punching and creasing tools.

[0015] The gripper carriage 8 transports the sheet 6 from the punching and embossing station 2 to the subsequent stripping station 3, which is equipped with stripping tools 21, 23. In the stripping station 3, the stripping tools 21, 23 push the unnecessary waste pieces 11 downward from the sheet 6, causing the waste pieces 11 to fall into a carriage-like container 12 inserted beneath the station.

[0016] From the stripping station 3, the sheet 6 passes into the delivery unit 4, where the sheet 6 is either simply deposited or the individual blanks of a respective sheet 6 are simultaneously separated. For this purpose, the delivery unit 4 has a blanking tool 21, 23. The delivery unit 4 can also contain a pallet 13 on which the individual sheets 6 or blanks are stacked in the form of a stack 14, so that after a certain stack height is reached, the pallet 13 with the sheet stack 14 can be moved away from the area of ​​the punching and embossing machine 100. In order to avoid having to stop the machine 100 during the stack change, auxiliary stacking devices can be used.

[0017] To align a sheet 6 from the stream of sheets conveyed in a shingled manner over the feed table 16, an alignment roller 24 is provided, which is in working contact with a counter roller 26. The alignment roller 24 is arranged in the feed table 16 such that a circumference of the alignment roller 16 comes into contact with the sheet 6 to be aligned. To ensure good contact between the sheet 16 and the alignment roller 24, a counter roller 26 is provided that can be adjusted to the alignment roller 24.

[0018] As an alternative to the counter roller 26, it is proposed to design the alignment roller 24 as a suction roller.

[0019] According to the proposal, the counter roller can also be replaced by a device that generates a blown air cushion.

[0020] In a device not according to the invention, the alignment roller 24 is designed as an elastic roller with a cylindrical body 35 that can be twisted along its axis 27. The alignment roller 24 is designed to be driven by two independently controllable drive motors 28, 29. The drive motors 28, 29 are coupled to two flanges 33, 34 of the alignment roller 24 by means of their drive shafts 31, 32. The flanges 33, 34 are connected to one another by means of a number of cross struts 36, wherein the cross struts 36 are arranged parallel to the axis 27 in the initial state of the alignment roller 24. Preferably, an articulated connection is provided between the struts 36 and the flanges 33, 34. The cylindrical body 35 of the alignment roller 24 consists essentially of an elastic material, e.g., rubber, caoutchouc, etc., which has a cylindrical shape in which the flanges 33, 34 and struts 36 provided for stabilization are cast in the elastic material.

[0021] The counter roller 26 has a number of freely rotatably mounted pressure wheels 37 arranged side by side. Preferably, the effective pressure surface of the pressure wheels 37 is more than 50% of the effective pressure surface of the alignment roller 24.

[0022] In an alternative embodiment not according to the invention according to the Fig. 4a, Fig. 4b, the cylinder body 35 is provided with a number of adjacently arranged rings 40, whose common axis of rotation is the axis 27. The rings 40 are connected to the struts 36 in such a way that they can be rotated relative to each other about the axis 27.

[0023] To align a first sheet 6, its leading edge is fed to the roller pair consisting of alignment roller 24 and counter roller 26. Based on sensor-determined position data, the sheet 6 is aligned in the transport direction in the case of a late arrival by driving the drive motors 28, 29 synchronously at an accelerated speed. In the case of an early arrival, the drive motors 28, 29 are driven with a corresponding delay.

[0024] To correct the skew, the drive motors 28, 29 are driven at different speeds depending on the sheet position. This action twists the alignment roller 24 and thus exhibits a speed curve that increases or decreases from left to right. The pressure wheels 37 of the counter roller 26 adapt to the speed curve of the alignment roller 24. Before the arrival of the next sheet, the alignment roller 27 is returned to its initial position according to Fig. 2a postponed.

[0025] In an embodiment of the invention according to Fig. 5, it is provided to reduce the pressure of the alignment roller 24 on a sheet by the alignment roller 24 having a number of at least three alignment wheels 38, 39, 41.

[0026] The outer alignment wheels 38, 39 are each driven by the drive motor 28, 29. The drive wheels 38, 39 are each arranged, for example, on a drive shaft 42, 43 of the drive motor 28, 29. At each end opposite the drive motor 28, 29, a bevel gear 44, 46 of a differential gear 47 is arranged, which drives the center drive wheel 41. The differential gear 47 continuously drives the center drive wheel 47 at a peripheral speed that corresponds to the average speed of the outer drive wheels 28, 29.

[0027] In a further embodiment of the invention according to Fig. 6, it is provided to replace the central drive wheel 41 by two drive wheels 51, 52 spaced apart from one another and driven at the same circumferential speed, which are driven by the drive motors 28, 29 by means of a common differential gear 53.

[0028] In a further embodiment of the invention according to Fig. 7, it is intended to provide a total of five drive wheels, wherein the middle drive wheels 55, 56, 57 are driven by the drive motors 28, 29 by means of a differential gear 58, 59, 61 each.

[0029] Alternatively, it is proposed to drive each drive wheel with its own drive motor, allowing each drive wheel to operate at its own speed profile. This measure allows an outer drive wheel to be driven at a higher speed than a drive wheel mounted on the other side, and the middle drive wheels can each be driven at an average speed depending on their position relative to the outer drive wheels. List of reference symbols 1 investor 2 punching and / or embossing stations 3 Stripping station 4 booms, if necessary with blank separation station 5 machine housing 6 sheets 7 Sheet transport system 8 gripper trolleys with grippers 9 Undercounter / lower pan 10 Upper table / upper crucible 11 pieces of waste 12 containers 13 pallets 14 display stacks 15 Control with interface and input devices 16 Feed table with a unit for aligning the sheets 17 Main drive 18 Suction head 19 sheet stacks 20 lower tool 21 Upper tool with stamps 23 Blank separator or stripping board (lower tool) 24 Alignment roller 25 . / . 26 Counter roller 27 Axis (24) 28 Drive motor 29 Drive motor 30 Upper tool (punching tool) 31 Drive shaft 32 drive shaft 33 flange 34 flange 35 cylinder bodies (24) 36 Strut 37 pressure wheel (26) 38 alignment wheel (24) 39 alignment wheel (24) 40 . / . 41 alignment wheel (24) 42 drive shaft 43 Drive shaft 44 bevel gear (42) 45 . / . 46 bevel gear (43) 47 differential gears 48 . / . 49 . / . 50 . / . 51 Drive wheel 52 drive wheel 53 differential gears 54 . / . 55 drive wheel 56 drive wheel 57 drive wheel 58 differential gears 59 differential gear 60 . / . 61 differential gear 100 Flatbed sheet punching and / or embossing machine (die-cutting machine) B Sheet transport direction E Sheet transport level

Claims

[1] Device for aligning a sheet by means of an alignment roller arranged transversely to the sheet transport direction, which has two independently drivable drives, characterized by , that the alignment roller has three drive wheels (38, 39, 41) arranged at a distance from one another, that the outer drive wheels (38, 39) can be driven directly by the drives (28, 29) assigned to them and that the middle drive wheel (41) can be driven by the drives (28, 29) by means of a differential gear (47). [2] Device for aligning a sheet by means of an alignment roller arranged transversely to the sheet transport direction, which has two independently drivable drives, characterized by , that the alignment roller (24) has four drive wheels (38, 39, 51, 52) arranged at a distance from one another, that the outer drive wheels (38, 39) can be driven directly by the drives (28, 29) assigned to them and that the middle drive wheels (51, 52) can be driven by the drives (28, 29) by means of a differential gear (52). [3] Device for aligning a sheet by means of an alignment roller arranged transversely to the sheet transport direction, which has two independently drivable drives, characterized by , that the alignment roller (24) has five drive wheels (38, 39, 55, 56, 57) arranged at a distance from one another, that the outer drive wheels (38, 39) can be driven directly by the drives (28, 29) assigned to them and that the middle drive wheels (55, 56, 57) can be driven by the drives (28, 29) by means of a differential gear (58, 59) each.

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