Differential reflectivity method and apparatus for sorting strip items

Claim 1

Apparatus for sorting slender elongate items, some of which are defective, comprising means defining a viewing area; means associated with said viewing area for sensing defects in such items and signalling when a defect is sensed, said sensing means including a plurality of paired sensing devices focused on the viewing area so as to view corresponding contiguous sub-areas of said viewing area; means defining a removal area; conveying means for passing the items through said viewing area and said removal area, including a conveyor adapted to receive the items randomly oriented in a flow of such items, said conveyor having upstanding walls defining a series of side by side channels extending longitudinally thereof along the direction of item travel for receiving said items and placing them in substantially singulated end to end alignment, and a second conveyor of endless belt type arranged as a longitudinal continuation of the first conveyor and having a series of troughs aligned longitudinally with said series of channels for receiving the singulated and aligned items from the channels of the first conveyor and for carrying the received items through said viewing area and into said removal area in substantially singulated end to end alignment, the width of each of the troughs of the belt conveyor comprehending a plurality of said sub-areas, and said paired devices being adapted to sense the two different wavelength bands, respectively, of energy reflected from the corresponding sub-areas; means for flooding the viewing area with radiant energy containing two mutually different wavelength bands in a substantially integrated spread throughout said viewing area; means for comparing the sensed radiant energy of one wavelength band with the sensed radiant energy of the other wavelength band from each sub-area of said viewing area and for producing data signals, respectively, for those sub-areas as to which the predetermined relationship between the sensed energy of different wavelength bands exists; means associated with said removal area for removing those items identified as defective by signals from the sensing means, said removal means including a plurality of removal devices arranged in side-by-side relationship across the width of the removal area so as to comprehend respective troughs of the belt conveyor whose widths correspond to a plurality of said contiguous sub-areas of the viewing area; and operating means responsive to data signals, for independently operating the removal devices in accordance with a predetermined number of data signals produced for respective corresponding pluralities of contiguous sub-areas of the viewing area, so as to remove from the items carried by the belt conveyor those which have produced the predetermined number of data signals.