Apparatus for monitoring rod-shaped commodities in cigarette making machines or the like

摘要

A cigarette making machine wherein discrete cigarettes travelling from the cutoff to a transfer conveyor slide along the upper side of a light transmitting guide. A photoelectric detector is mounted below and is shielded by the guide from tobacco dust which is swept away by successive cigarettes. The light source of the detector emits a light beam which passes upwardly through the guide, is reflected by successive cigarettes and thereupon passes downwardly through the guide prior to reaching the photosensitive transducer of the detector. Alternatively, the light source or the detector can be mounted above the guide and above the path of the cigarettes so that the light beam can reach the transducer after having passed through the guide only once, provided that the beam is not interrupted by the cigarettes.