GB1489107A - Sorting machine with digital error correction - Google Patents

Abstract

1489107 Sorting articles GEOSOURCE Inc 18 March 19.75 [29 March 1974] 11213/75 Heading G1A An apparatus for sorting articles according to light reflecting properties comprises viewing means 12 for sensing light energy reflected from an article 10, e.g. a coffee bean, to be sorted, the viewing means producing an electrical signal indicative of the light-reflective properties of the article, an amplifier 36 directly coupled to the viewing means for amplifying the electrical signal and preferably an ejector 50 operatively coupled to the amplifier for deflecting an article having predetermined lightreflective properties and responding to a corresponding amplified electrical signal. A normalizer 78 is operatively coupled to the amplifier 36 and includes a reference for checking a predetermined signal as from a background 22 from the viewing means via the amplifier, a digital counter (140), Fig. 2 (not shown), for defining discrete stepwise signals corresponding to an error correction signal required for imbalance between the reference and predetermined signals and digital to analog converting means for introducing the output signals from the digital counter to the amplifier as corresponding analog signals. The error signal is introduced into the amplifier through a feedback loop 76. As shown the viewing means comprises a beam-splitter 14. light from which falls on a pair of filters 15, 16. Filtered light from each filter 15, 16 passes through an associated frame 17, 18 on to a respective photo-sensitive element 19, 20 e.g. a silicon solar cell. Each element 19, 20 is coupled to its own amplifier 36, 37. The signal from each amplifier, as well as being fed to its associated normalizer 78 is also fed to an inverter 38, 39 to produce a second signal for feeding into the normalizer. These two signals from each circuit are then fed to an electronic pattern 40 which, in turn, feeds four level discriminators 41-44 which control the actuation of the ejector 50. The apparatus is checked periodically for error by the closing of a switch, Fig. 3 (not shown), whereby both the object feeder and the ejector are immobilized. The check may also be instigated at will by the closure of a second switch (272, Fig. 3). There may be a delay introduced between the viewing of an object and the time of possible ejection of the same.