Method and apparatus for forming an auxiliary stack

Abstract

Method for forming an auxiliary stack when changing a sheet stack in a sheet boom of a sheet processing machine, comprising an auxiliary stack support device for supporting the auxiliary stack during a non-stop stack change, with several stop and separating elements arranged outside the stack area in front of edges of the sheet stack to form a gap in a stream of sheets conveyed and released by a conveyor system falling onto the sheet stack, wherein the sheet stack is lowered to form a gap for the auxiliary stack support device. characterized by that the stop elements (28, 29) are moved from a working position at the edges of the sheet stack to a waiting position spaced apart from the edges of the sheet stack immediately before the sheet stack (21) is lowered, that after the sheet stack (21) is lowered by a distance (a) a sheet holding element (38) for the sheet trailing edge is inserted into the sheet stack area, that the stop elements (28, 29) for the sheet stack edges are moved back into the working position and that a bow holding element (37) for the bow leading edge is then inserted into the stacking area.

Description

[0001] The invention relates to a method for forming an auxiliary stack when replacing a stack of sheets in a boom of a sheet processing machine.

[0002] A method and a device according to the preamble are already known from DE 102005058197 A1. In this method, a stack of sheets arranged between front edge stops and rear edge stops is first lowered a certain distance to create a gap for receiving an auxiliary stack support. After the sheet stack has been lowered, sheet holders are moved into the stack area from the rear (viewed in the direction of sheet transport) and from the front (viewed against the direction of sheet transport) to temporarily catch subsequent sheets. The auxiliary stack support is then moved into the stack area from the rear. In a final step, the sheet holders are removed from the stack area, so that the auxiliary stack support completely receives the sheets that were temporarily held.

[0003] The front edge and back edge stops are positioned without play against the rear and front sides of the stack to achieve good stacking.

[0004] When lowering the stack of sheets, the problem arises that the upper layers of sheets cannot easily follow the stack, as they can get stuck on the front and rear edge stops.

[0005] Further state of the art includes DE4217816A1, DE3906649A1 and DE19541792A1.

[0006] The invention is therefore based on the objective of creating a method for automatic stack replacement that ensures safe gap formation for the insertion of an auxiliary stack carrier.

[0007] The problem is solved according to the invention by the features of claim 1.

[0008] It is a particular advantage that, before lowering the stack of sheets to create gaps, the front and rear edge stops, which initially lie flush against the stack of sheets, are spaced away from the stack of sheets so that the upper layers of sheets can follow the stack of sheets without interference.

[0009] In a further advantageous process step, the stops are moved back into a position free of play relative to the auxiliary sheet stack to achieve good auxiliary stack formation, preferably before the sheet holders are removed from the stacking area.

[0010] In a particularly advantageous manner, all elements provided for carrying out the method according to the invention are designed to be remotely adjustable, so that a fully automatic change of a sheet stack is possible. Further advantageous embodiments are described in the dependent claims.

[0011] The invention can also be used on a sheet-fed die-cutting machine.

[0012] An embodiment of the invention is illustrated in the drawings and is described below. The drawings show... Fig. 1. A cross-section of a sheet-fed rotary printing press in a schematic representation, Fig. 2. A cross-sectional view of the boom of a sheet-fed rotary printing press, Fig. 3 - 6 the boom of the sheet-fed rotary printing press in cross-section in different positions.

[0013] A sheet-processing machine 7, e.g., a printing press 1, has a feeder 2, at least one printing unit 3 or 4, and a delivery unit 6. The sheets 7 are taken from a stack of sheets 8 and fed singly or in batches via a feed table 9 to the printing units 3 and 4. These units each contain a plate cylinder 11, 12, as is known. The plate cylinders 11 and 12 each have a device for attaching flexible printing plates. In addition, each plate cylinder 11, 12 is assigned a device for semi- or fully automatic plate changing.

[0014] The stack of sheets 8 rests on a controllably liftable main stacking plate 10. The sheets 7 are removed from the top of the stack 8 by means of a suction head 18, which includes, among other things, a number of lifting and trailing suction cups for singulating the sheets 7. In addition, blowing devices are provided to loosen the upper layers of sheets, and sensing elements are provided for stack tracking. A number of lateral and rear stops are provided for aligning the stack 8, in particular the upper sheets 7 of the stack 8.

[0015] To perform a non-stop stack change in the boom 6, it is provided that a main stack 21 can be removed from the boom 6 while an auxiliary stacking device 22 forms a new stack 23.

[0016] The main stacking device 24 is suspended vertically on lifting chains 26 which are driven by means of a lifting motor 25 and the auxiliary stacking device 22 is also suspended on driven lifting chains (not shown) so as to be movable.

[0017] To form the main stack 21, a front edge stop 28 and a rear edge stop 29 are provided, as shown in Fig. 2 shown by means of positioning devices 31, 32, are positioned without play against a stack's front edge and stack's rear edge, respectively. The positioning device 31 is an actuator, for example, a pneumatic cylinder. The positioning device 32 is an actuator, for example, a driven shaft with a chain and a linear guide for horizontally displacing the rear edge stop 29.

[0018] To remove the main stack 21 from the boom 6 without interrupting the stack formation, sheets fed into the stacking area must be caught by the auxiliary stacking device 22. For this purpose, an auxiliary stacking support device 33, e.g., in the form of a support plate, a rake, or a roller blind, is moved into the stacking area. To ensure that this action can be carried out without disturbing the stack formation, the leading and trailing edge stops 28, 29 are first moved away from the trailing and leading edges of the stack, respectively, by means of the actuators 31, 32. In the preferred embodiment according to Fig. 3 The front edge stop 28 is pivoted away from the main stack 21 about a pivot axis 34 arranged at the height of the auxiliary stack support 33 on the auxiliary stack support device 22.

[0019] Then, according to Fig. 4 of the main stack 21 to form a gap for the intended arch support elements 37, 38 a first path a lowered.

[0020] A gap detection sensor 39 stops the main stack 8 in the lowered position upon detecting a gap and generates a signal to retract the rear sheet-holding elements 38 into the sheet stack area. The sheet-holding element 38 for the sheet's trailing edge is designed as a separating belt, which is preferably inserted into the stack area transversely to the sheet transport direction. An actuator 40 is provided for driving the separating belt.

[0021] After the rear arch support elements 38 have been inserted according to Fig. 5. The stack front and rear edge stops 28, 29 are reset to the format length to be processed.

[0022] In a subsequent step, the sheet holding element 37 for the sheet leading edge, consisting of a number of fingers arranged transversely to the sheet transport direction, is moved into the sheet stacking area. The fingers are designed to be movable in two end positions by means of a remotely actuated positioning device 36, e.g., an actuator in the form of a pneumatic cylinder.

[0023] To create a larger gap for receiving the auxiliary stack support plate 33, the main stack 21 is lowered by a further distance b so that the auxiliary stack support 33 can be inserted into the stacking area.

[0024] For extending and retracting the auxiliary stack carrier 33, it has actuating means in the form of horizontally guided chains (not shown) which are driven by an actuating motor 35.

[0025] In a further step, the separating band 38 for the rear edge of the sheet and the sheet holding elements 37 for the front edge of the sheet are moved back from the stacking area to their waiting position.

[0026] While the auxiliary stack 23 on the auxiliary stack support device 33 is limited by front edge and rear edge stops 28, 29 according to Fig. Once 6 is formed, the main stack 21 can be removed from the boom.

[0027] To place the auxiliary stack 23 onto the stacking plate 41 of the main stack 21, the stacking plate 41 or a pallet 42 placed on it is raised by means of the lifting chains 26 until it is just below the auxiliary stack support plate 33. By moving the auxiliary stack support plate 33 out of the stacking area into a waiting position, the auxiliary stack 23 is placed onto the pallet 42 or the stacking support plate 41. The auxiliary stack 23 is now the new main stack 21.

[0028] For remotely adjustable automatic control of all actuators and actuators involved in the non-stop stack change, these are connected to a control computer 43. Reference symbol list 1 printing press 2 investors 3 Printed matter 4 Printing work 5 . / . 6 outriggers 7 sheets 8 stacks of sheets 9 Feed table 10 stacking plates 11 plate cylinders 12 plate cylinders 13 Pressure plate mounting 14 Pressure plate mounting 15 . / . 16 printing plate changers 17 printing plate changers 18 suction heads 19 vacuum cleaners 20 . / . 21 Main Stacks 22 Auxiliary stacking device 23 . / . 24 . / . 25 Hub motor (26) 26 Lifting chain (41) 27 . / . 28 Front edge stop 29 Back edge stop 30 . / . 31 Control devices (28) 32 Control devices (29) 33 auxiliary stackers 34 Swivel axis (28) 35 Actuator (33) 36 Control devices (37) 37 Bow support element (front edge) 38 Bow support element (rear edge) 39 Gap sensor 40 actuator 41 stacking plate 42 pallets 43 tax calculators

Claims

[1] Method for forming an auxiliary stack when changing a sheet stack in a sheet boom of a sheet processing machine, comprising an auxiliary stack support device for supporting the auxiliary stack during a non-stop stack change, with several stop and separating elements arranged outside the stack area in front of edges of the sheet stack to form a gap in a stream of sheets fed and released by a conveyor system falling onto the sheet stack, wherein the sheet stack is lowered to form a gap for the auxiliary stack support device, characterized by , that the stop elements (28, 29) are moved from a working position at the edges of the sheet stack to a waiting position spaced apart from the edges of the sheet stack immediately before the sheet stack (21) is lowered, that after the sheet stack (21) is lowered by a distance (a) a sheet holding element (38) for the sheet trailing edge is inserted into the sheet stack area, that the stop elements (28, 29) for the sheet stack edges are moved back into the working position and that a bow holding element (37) for the bow leading edge is then inserted into the stacking area. [2] Method according to claim 1, characterized by , that the stack (21) is then lowered a further time by a distance (b) before an auxiliary stack support (33) is moved into the stacking area. [3] Method according to claim 1 or 2, characterized by , that all adjustments are made by means of remotely operated actuators controlled by a control computer (43).

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