Patent GB-287596-A (GB)
Title: Improvement in color-controlled sorting machine
IPC: B07C5/342
Filed: 1926-11-17
Abstract: 287,596. Marks, E. C. R. (Photometric Products Corporation). Nov. 17, 1926. Light rays, controlling sorting-apparatus by.- A machine of the kind described in Specification 196,307 for automatically sorting cigars and other objects according to colour comprises an endless conveyor having a series of grippers into which the objects to be sorted are indiscriminately loaded, the objects while travelling along the upper run of the conveyor being exposed to a source of light and examined by a photo-electric cell, and the grippers being released at a predetermined point in their lower run by mechanism, controlled electrically by the photo-electric cell. The grippers consist of two members 75, Figs. 9 and 10, connected by segmental gearwheels 80 and closed by springs. The grippers are carried by two endless chains 29 and one member carries an extension arm 82 provided with a transverse bar 83, Fig. 7, and a roller 84. During the upper run of the conveyor towards the photo-electric device, the roller 84 engages a cam rail 85 which holds the grippers open. The bar 83 has a series of notches 88 each corresponding to a receiving bin and a rider 87 is set and held at one of the notches as the gripper with its load passes under the photoelectric cell. The rider-setting apparatus is shown in Fig. 6 and consists of a carriage 91 which makes one complete reciprocation, actuated by a connecting rod 109 and cam 112 on the driving shaft, for each step of the conveyor. The carriage has two pivoted spring- controlled levers 93, 94 and two sliding cams 96, 97 by which the levers are raised against the action of the springs. The lever 93 is held in its upper position by a detent 98 which is controlled by an electromagnet 99. At the beginning of the setting stroke the parts are in the position shown, and the carriage moves to the right with the lever 93 engaging the rider 87. At a point in the traverse determined by the photo-electric device the magnet 99 is energized and the detent 98 released, allowing the lever 93 to drop and disengage the rider. At the end of the traverse the cams 97, 96 are moved to the left and the lever 94 is raised so that, in the return stroke, it moves the rider of the next gripper to the zero point. The cams again engage a fixed abutment and the levers are reset as shown. After leaving the photo-electric device the grippers close on their load which is carried over a series of bins each having a trip gear corresponding to one of the settings of the rider and adapted to act through the rider to open the grippers and discharge the objects into the various bins. The photo-electric cell 40 is contained in a housing 39 and receives the light from two lamps 38 rejected from the surface of the object under examination through the passage 117. The lamp housing has a vertically moving eyelid 118 which is alternately brought down on to the object and raised in synchronism . with the movements of the other parts. The sides of the passage 117 have two hinged shutters 124 which, in the raised position of the eyelid, close the passage to reflected light and directly admit to the cell 40 an amount of light which is controlled by shutters 127 so as to equal the light reflected from the objects of medium shade. The object of this arrangement is to provide an automatic correction of the apparatus between the different exposures. The current produced by the light passing to the cell 40 is amplified by a single or multiple stage thermionic valve-system and actuates an electromagnetic Indicator 144 which moves between a movable jaw 147 and a series of flexible fingers 150 each registering with one of the fixed terminals 151 each of which corresponds to one receiving bin. The terminals 151 communicate through a commutator 167 each with a terminal 161 on a timing-device 160. At each setting of the indicator the jaw 147 is depressed and completes the circuit 137 through the terminals 151, 161 and electromagnet 99. The timing-device comprises an arm 164 rotating around the disc 160 in synchronism with the reciprocation of the setting device and carrying a roller 162 contacting with each of the terminals 161 in turn. The electric connections of the cell and amplifying system are shown in Fig. 9. The main circuit 137, which supplies the lamps, has its negative pole connected through the potentiometer 42 and high resistance 135 to one electrode of the cell, the other electrode of which is connected through the high-voltage battery 138 to the positive pole of the circuit 137. The valve filaments are connected in series across the source 137 and in parallel with the potentiometer 42. The plate circuit of the first valve 45 includes a battery 140, resistance 141, and variable portion of a resistance 142 connected between the filaments. The grid of the second valve 45a is connected to a tapping on the battery 140. The commutator 167 interrupts the connection between the terminals 151, 161 during a portion of each cycle and diverts the current through a device 43 for adjusting the potentiometer controlling the amplifying device during the time that the eyelid is raised and the cell 40 is receiving light direct from the lamps. The device 43 consists of two solenoids 170, 172 adapted to attract the armatures 177 on a spring-balanced arm 176 which carries two spring pawls adapted to engage a ratchet wheel 173 on the shaft 174 of the potentiometer. The commutator connects the terminals 151 in two groups, one on each side of the medium terminal, to either of the solenoids 170, 172 and, according to the variation from mean conditions that has occured during a cycle, the potentiometer control is adjusted.