Device for aligning the trailing edge of a sheet or stack in the boom of a sheet processing machine

Abstract

Device for aligning a sheet or stack trailing edge in a sheet processing machine with a stack trailing edge stop (36) and a sheet braking device (33), wherein a sheet stop (46) bridging a gap between the sheet braking device (33) and the stack trailing edge stop (36) is provided and the sheet stop (46) is arranged to be movable transversely to the sheet transport direction, characterized in that the sheet stop (46) is arranged to be displaceable along the stack trailing edge stop (36), wherein the stack trailing edge stop (36) forms a guide in the form of a rail on which the sheet stop (46) is guided displaceably transversely to the sheet transport direction for the sheet stop (46).

Description

The invention relates to a device according to the preamble of claim 1. In DE 39 23 475 A1 a bow stop for the bow trailing edge in bow cantilevers is described, which is arranged to pivot transversely to the bow transport direction. DE 197 09 083 C1 describes a device for the axial adjustment of sheet brakes in a boom of a printing press, in which trailing edge stops are arranged below the sheet brake, which are movable in the vertical direction during non-stop stack changes or when raising or lowering the main stack. In DE 36 18 622 A1 a trailing edge stop for sheet booms on sheet processing machines is described, wherein a traverse is articulated to a sheet brake by means of a support scissor, on which a sheet stop is provided, in which a brush adjustable towards the side of the sheet is arranged in a recess, which is pivotably mounted about a horizontal axis transverse to the sheet travel direction with a brush holder. In DE 20 47 808 B a sheet boom for printing presses is described in which sheet stops are pivotably mounted on bolts attached to brackets of the sheet brake device. German patent DE 43 17 357 C1 describes a device for the precise separation of an auxiliary stack from a main stack in non-stop delivery systems of sheet-fed printing presses, wherein upper stops are arranged on a transverse crossbeam, extending vertically upwards between the sheet braking device. A crossbar is arranged below the crossbeam, to which a support is attached. The crossbeam, the crossbar, and the support are connected by several joints such that the support and the crossbar are vertically movable up and down relative to the stationary crossbeam. DE 197 22 356 C1 discloses, for example, a device for aligning the trailing edge of a stack of sheets, wherein sheet stops are attached side by side at a distance on a crossbeam and, in addition, two stop systems are provided which support height-adjustable stop bars by means of a so-called "scissor lattice mechanism". Both stop systems are fixed to the traverse and therefore cannot be adjusted perpendicular to the direction of bow transport. The invention is based on the objective of creating at least one device with a bow stop that can be used variably. The problem is solved according to the invention by a device having the features of claim 1. The easily removable sheet stops allow them to be positioned at different points perpendicular to the sheet transport direction, thus acting as guides for the sheets. This allows the sheet stops to be optimally positioned regardless of the position of the braking device or the quality or width of the sheets being processed. The bow stop can be coupled to a remotely adjustable braking device via a drive mechanism. This allows the bow stop to be automatically adjusted in conjunction with a preset setting of the braking device. The integrated magnets easily and releasably fix the bow stop in the desired position. The bow stop is preferably made of a non-electrically conductive material, such as plastic. This allows the bow stops to be used without problems even in the vicinity of bow de-electrification devices. An embodiment of the invention is shown in the drawings and is described below. Figure 1 shows a schematic section of a sheet-fed rotary printing press, Figure 2 shows a schematic cross-section through the sheet stop, Figure 3 shows a schematic top view of the sheet stop, and Figure 4 shows a cross-section through the sheet stop with spur gears. 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 13, 14 for attaching flexible printing plates. In addition, each plate cylinder 11, 12 is assigned a device 16, 17 for semi- or fully automatic plate changing. The stack of sheets 8 rests on a stacking plate 10 that can be raised in a controlled manner. The sheets 7 are removed from the top of the stack of sheets 8 by means of a so-called suction head 18, which includes, among other things, a number of lifting and trailing suction cups 19, 21 for singulating the sheets 7. In addition, blowing devices 22 are provided for loosening the upper sheets and test elements 23 for stack tracking. A number of lateral and rear stops 24 are provided for aligning the stack of sheets 8, in particular the upper sheets 7 of the stack of sheets 8. The sheet 7 is conveyed through the printing press by means of a number of sheet-transporting cylinders 31, 41 and, if necessary, a turning device 26 – consisting of a transfer drum 27, a storage drum 28, and a turning drum 29 – and fed to a chain gripper system 32. A sheet braking device 33 is provided to reduce the sheet speed when the sheet 7 is deposited onto the sheet stack 8. This device essentially consists of at least one, for example, a suction belt 34, which slows the sheet. To achieve a stack 8 with precise stacking edges, leading edge stops 35 and a trailing edge stop 36 are provided, which extends transversely to the sheet transport direction and is coupled to a parallel crossbeam 37. The crossbeam 37 is mounted so that it can be moved in or against the sheet transport direction to adjust the format length. The trailing edge stop 36 can be angled in a horizontal plane relative to the crossbeam 37 so that it can be precisely positioned even against an angled trailing edge of a stack of sheets. A bracket 38 is provided on the crossbeam 37, adjustable transversely to the direction of arc transport, on which a module carrier 39 is pivotably mounted in a horizontal plane about a pivot axis 30. A brake module 42, which carries, for example, the suction belt 34, is mounted on the module carrier 39 and is pivotable upwards or downwards about a horizontal axis 40. The module carrier 39 further comprises a driver 45 which engages in a receptacle 44 of a bow stop 46. The bow stop 46 is slidably or easily removable on the rear edge stop 36. Magnets 47 are provided to fix the bow stop 46. These magnets are attached to a non-electrically conductive housing (e.g., plastic housing) of the bow stop 46 and adhere to the rear edge stop 36 by magnetic force. Here, the trailing edge stop 36 forms a guide for the sheet stop 46 in the form of a rail, on which the sheet stop 46 is guided so as to be slidable transversely to the sheet transport direction. Naturally, the sheet stop 46 can also be removed from the trailing edge stop 36 and reattached to the trailing edge stop 36 in a different position. The sheet stop 46 has a guide surface 49, which points in the direction of sheet transport and serves as a guide for the trailing edge of the sheet. The guide surface 49 bridges a gap between the suction belt 34, the braking device 33, and the trailing edge stop 36, which is positioned against the sheet stack 8. The guide surface 49 of the sheet stop 46 can have different shapes depending on the operating mode: perfect printing or perfecting and double printing. For this purpose, these shapes are interchangeable with corresponding sheet stops. The sheet stop 46 has on its upper surface 51 a receptacle for a so-called spur wheel 52, which supports the sheet across the format width in lateral areas spaced apart from the suction belt 34. To de-electrify the arc, de-electrification devices 48 are arranged on the trailing edge stop 36. Reference symbol list 1 Printing press 2 Feeder 3 Printing unit 4 Printing unit 5 . / . 6 Delivery 7 Sheet 7a Next sheet 8 Sheet stack 9 Feed table 10 Stacking plate 11 Plate cylinder 12 Plate cylinder 13 Plate clamping 14 Plate clamping 15 . / . 16 Plate changer 17 Plate changer 18 Suction head 19 Lifting suction 20 . / . 21 Trailing suction 22 Blowing device 23 Key element 24 Stop 25 . / . 26 Turning device 27 Transfer drum 28 Storage drum 29 Turning drum 30 Swivel axis 31 Sheet transport cylinder 32 Chain gripper system 33 Sheet braking device 34 Suction belt (33) 35 Leading edge stops 36 Trailing edge stop 37 Crossbeam 38 Bracket 39 Module carrier 40 Axle 41 Sheet transport cylinder 42 Brake module 43 Suction belt 44 Mount (46) 45 Driver (39) 46 Sheet stop 47 Magnets 48 De-electrification device 49 Guide surface (46) 50 . / . 51 Top (46) 52 Spur wheel

Claims

Device for aligning a sheet or stack trailing edge in a sheet processing machine with a stack trailing edge stop (36) and a sheet braking device (33), wherein a sheet stop (46) bridging a gap between the sheet braking device (33) and the stack trailing edge stop (36) is provided and the sheet stop (46) is arranged to be movable transversely to the sheet transport direction, characterized in that the sheet stop (46) is arranged to be displaceable along the stack trailing edge stop (36), wherein the stack trailing edge stop (36) forms a guide in the form of a rail on which the sheet stop (46) is guided displaceably transversely to the sheet transport direction. Device according to claim 1, characterized in that the arc stop (46) is fixed to the stack rear edge stop (36) by means of magnetic force. Device according to one of claims 1 to 2, characterized in that the bow stop (46) is made of a non-electrically conductive material. Device according to one of the preceding claims, characterized in that the bow stop (46) is coupled to the adjustable bow braking device (33). Device according to claim 4, characterized in that the bow stop (46) together with the bow braking device (33) is arranged to be remotely adjustable. Device according to one of the preceding claims, characterized in that the bow stop (46) has a guide surface (49) pointing in the bow transport direction for a bow trailing edge. Device according to one of the preceding claims, characterized in that the bow stop (46) has a receptacle (44) for a spur wheel (52). Device according to one of the preceding claims, characterized in that the arc stop (46) can be fixed at any position along the stack rear edge stop (36). Device according to claim 8, characterized in that the bow stop (46) can be positioned in the area of ​​provided de-electrification devices (48).

Images