Apparatus for sensing moving particles or small moving objects

Abstract From the Canadian patent

A detector for sensing the presence of grain in straw or chart discharged from a combine has an elongated flat target plate extending across the machine. It is mounted on a relatively massive base through the intermediary of longitudinal resilient strips which allow, transverse bending. Transducers mounted on the reverse side of the plate provide an output from which sharp grain impact signals can be filtered. The resilient strips are best arranged along nodes of a selected harmonic preferably the second, of the transverse bending vibrations of the plate. The detector can be used generally for sensing small particles.