초록

An apparatus for detecting the presence of at least one object in a field having at least one through-beam detection device with at least one transmitter and at least one opposing detector to create a detection beam that overlaps the field.

대표청구항 ▼

[ What is claimed is:] [1.] An apparatus for detecting the presence of at least one object in a field, the apparatus comprising:at least two through-beam detection devices, each device comprising at least one transmitter and at least one opposing detector that are fixed relative to each other and th

[ What is claimed is:] [1.] An apparatus for detecting the presence of at least one object in a field, the apparatus comprising:at least two through-beam detection devices, each device comprising at least one transmitter and at least one opposing detector that are fixed relative to each other and that create a detection beam that overlaps the field, at least two of the devices being horizontally offset from each other so as to create horizontally offset detection beams; andmeans for moving said devices around the field to detect at least one object in the field.