| 摘要 |
Device for scanning lengths of sheets in a sheet-processing machine, wherein the sheets travel with a leading and a trailing edge, including suction-air measuring nozzles alignable with the trailing edges of the sheets and connected to a suction-air source via control elements connected in an electrical circuit of the machine drive, a feeder for aligning the sheets to be processed at stops for the leading edges of the sheets, lift-type suckers for lifting the sheets individually off a pile of sheets, and have structure defining a scanning hole in at least one of the suction-air measuring nozzles, the one nozzle being disposed in the feeder and being directed towards the trailing edge of an uppermost sheet disposed on a pile of sheets, a suction-air connecting line connecting the one nozzle to the suction-air source, and a differential pressure-measuring valve connected in the line and cooperatively associated with the control elements.
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