GB1482796A - Scuffed container detector - Google Patents

Abstract

1482796 Detecting roughness photo-electrically BARRY-WEHMILLER CO 7 Nov 1974 [14 Nov 1973] 48254/74 Heading G1A Apparatus for detecting surface roughness on transparent containers comprises: means to move containers in single file through a detection station; a source arrangement directing a slanting narrow light beam down through a container; means spaced horizontally from the light beam to detect light scattered by any illuminated surface roughness of the container; and means generating a signal when the detected light exceeds a predetermined intensity. A conveyor 10 Fig. 1 moves transparent containers 11 towards a pair of star wheels 14, 15 wherein they are constrained by a belt 20 to traverse a detection station. At an inspection point each container in turn interrupts a light beam illuminating a photo-cell 24, which triggers a timing pulse generator, (58) Fig. 4 (not shown) to operate a visual timing indicator (59). Light from a short-filament lamp 36, imaged at F behind an adjustable sharpedged aperture 39, is collimated at 46 and reflected down by the front surface 47 of an adjustable mirror 48 in the form of a narrow beam inclined at an angle A (15-35 degrees) to the vertical container axis, so that when admitted by a slot 27 in the upper wheel 14, it penetrates the container 11 and illuminates its opposite wall in a zone where scuffing is expected. A photo-multiplier, 34 Fig. 3, receives any light scattered horizontally at an angle B (20- 40 degrees) to the normal at the illuminated surface, its field of view being restricted, by apertures 29 and 32. The sensitivity of the arrangement is controlled by a Ronchi grating in the aperture 29, and, if the containers are coloured, a filter may be used in the aperture 32. The photo-multiplier 34 output after amplification at (54), Fig. 4 (not shown) is applied to a comparator (55) where it is compared with a threshold signal derived from an adjustable element (56). Any output from the comparator (55), when gated (at 60) by the timing pulse, operates a visual reject indicator (62) and a reject counter (63), and energizes a solenoid 18, Fig. 2 which actuates a suction cup 17. The faulty container 11 is thus held in the star wheels 14, 15 Fig. 1 until released by a reset device (not shown) and so deposited in a rotating collection table 19. Acceptable containers 11 proceed, unrestrained, from the star wheels 14, 15 to a carry-off conveyor 10A