Device for guiding signatures, particularly in the region of a wedge-shaped outlet of a cutting cylinder device in a folder of a rotary printing machine

#The invention relates to a device for guiding signatures, particularly in the region of a wedge-shaped outlet of a cutting-cylinder device in a folder of a rotary printing machine.

#Folders of rotary printing machines, particularly of web-fed rotary offset printing machines, are beset by a problem that, after a longitudinal folding operation on a continuous paper web, signatures severed therefrom by revolving cutting blades do not undergo any defined guidance during and after the cutting operation. This may result in disruptions during the subsequent transportation of the signatures, if the latter enter, for example, onto endless transporting belts arranged downline in the cutting-cylinder arrangement, above and below the transporting path of the signatures, in order for the latter to be fed to a further-processing device, in particular a folder.

#One of the most common causes of disruption occurring as the signatures enter onto the downline transporting belts is that the leading corners of the signatures fold over and form so-called “dog ears” as the signatures enter onto the transporting belts. This results not only in the printed products being unusable as such, and having to be separated out in corresponding downline devices, for example, in reject or waste paper diverters, but rather also, there arises a risk that the damaged signatures, during subsequent folding operations, result in a paper build-up which may frequently be associated with production failures or even damage to the folder.

#FIG. 1 is a diagrammatic side elevational view of a signature-guiding device according to the invention having a first and a second guide belt arranged at least approximately parallel to a transporting path of the signatures;

#FIG. 2 is a view similar to that of FIG. 1 of a further embodiment of the signature-guiding device according to the invention, wherein, above and below the transporting path of the signatures, the first and the second guide belts are arranged at an angle to the transporting path and form a funnel-shaped inlet region for leading edges of the signature into a downline section of the transporting belts;

#FIG. 3 is a cross-sectional view of the first embodiment of the signature-guiding device according to the invention, facing in the direction of the signature-transporting path, wherein an endless guide belt is guided over two deflecting rollers located outside the transporting path; and

#Referring now to the drawings and, first, particularly to FIG. 1 thereof, there is shown therein a signature-guiding device 1 according to the invention provided for guiding signatures 2 in the region of a wedge-shaped outlet 4 of a cutting-cylinder device 8 having a cutting blade 6, which is included in an otherwise non-illustrated folder of a web-fed rotary printing machine, the signature-guiding device 1 having one or more flat guide belts 10, 12 according to the invention which are arranged on both sides of a signature-transporting path 14. The guide belts 10 and 12 have respective guide surfaces 16 and 18 which are directed towards the outer sides of the signatures 2 and guide leading ends 20 of the signatures 2 in the region of the wedge-shaped outlet 4 and, as the signatures enter onto a transporting-belt device 26 formed by transporting belts 22 and 24, in order to prevent the leading ends 20 of the signatures 2 from creasing or folding over as the signatures enter the transporting-belt device 26.

#As is illustrated in FIG. 3, the signature-guiding device 1 according to the invention includes two deflecting rollers 28 and 30, one deflecting roller 28 of which is arranged on a first side wall 32 of the printing machine, and the other deflecting roller 30 is fastened rotatably on a tensioning device 34, which is movable relative to a second side wall 38. The tensioning device 34 here includes a lever arm 36 which is pivotable about a rotary pin 40 which is preferably stationary relative to the second side wall 38 of the folder. The lever arm 36 is forced, by a spring 44 which can be prestressed by an adjusting screw 42, against a rotatable eccentrically mounted or non-round cam 46 so that, by rotating the cam 46, the lever arm 36 can be pivoted from the tensioning position for the guide belts 10 and 12, which is illustrated in FIG. 3, into a non-illustrated position wherein the guide belts 10 and 12 according to the invention are in a non-tensioned state and are removable, for example, easily from the deflecting rollers 28 and 30. As can also be concluded from FIG. 3, the signatures 2 are guided through, between the inner sides 16 and 18, respectively, of the endless guide belts 10 and 12, those inner sides 16 and 18 being providable with a coating which reduces friction, or prevents smearing of the signatures 2, and forming guide surfaces.

#Instead of using a deflecting roller 28 locally fixed to the first side wall 32 of the folder, it may also be advantageous, as shown in FIG. 4, to use an open-ended guide belt 110, the ends 111 and 113 of which are fastened to the first side wall 32 of the folder with the aid of a fastening device, in particular by hooks 115 and 117, respectively, which engage in the respective ends 111 and 113 of the open-ended guide belt 110.