UEBERWACHUNGSEINRICHTUNG FUER EINE REGALGASSE

摘要

The alleyway-monitoring device disclosed has, mounted at different heights, two light barriers (16 to 26, 28 to 30), the higher of which is at a height at which the light beam can be broken only by fork-lift trucks. The light barriers produce output signals which enable the direction of motion of the objects which break the beam to be determined, the output signals being passed to associated up/down counters (50, 52) which are in turn connected to the inputs of a monitoring circuit (54). The monitoring circuit triggers an acoustic alarm (56) if non-permitted counter-reading combinations occur.