Patent GB-1022840-A (GB)
Title: A control system in or for article sorting apparatus
Inventor: GAULT VINCENT ARTHUR
IPC: B65G47/50
Filed: 1964-05-20
Abstract: 1,022,840. Sorting parcels; conveyers. MULLARD Ltd. Nov. 24, 1964 [May 20, 1964], No. 20808/64. Heading B8A. A control system in or for article sorting apparatus of the type including an endless conveyer having a number of receiving points for articles located along its length, said articles being placed on the conveyer at one point and routing means being operated through the control system so that each article is removed from the conveyer at the correct receiving point and not at any other point, comprises a 100-foot long conveyer belt run (not shown), having 15 receiving points for articles spaced along its length, and moving at 180 feet a minute. Operators stand at twin keyboards 1, 2 placed either side of the belt: each button on the keyboards is labelled with a destination associated with one of the receiving points, which destination may correspond to that of a parcel to be sorted. The conveyer belt is indined at an angle so that the parcels slide on a support section at right angles to the belt. At the receiving points solenoid operated gates are arranged which are hinged to open so that a parcel may fall through on to a shoot below. The run of the belt is considered to be 512 units each of 2À34 inches so that, using a binary count, nine bits are required. A bit is also required to indicate whether or not a word is occupied, and as four bits are required to cater for the 15 receiving points the total length of the word is 14 bits. A memory section 5 comprises a delay line 6 connected in a loop with an adder 7 and a register 8. The storage time of the delay line 6 is 3À22 m.S. so that with a repetition rate of 100 kc./s. (from a clock 12 and control section 13), 322 bits may be stored. One word is always stored in the loop, the rest of the words in the delay line 6 so that a total of 24 parcels may be loaded on to the conveyer without overloading the system. The register 8 is considered in three parts: a first part 9 indicative of the presence or absence of a word in the register, a second part or count 10 indicative of the position of a parcel on the belt and a third part 11 indicative of the parcels identity or destination. When an operator presses a button on either keyboard 1, 2 an encoder 3 passes the coded destination to a temporary store 4. When part 9 indicates a vacant word and a photodetector 18 detects a parcel at a predetermined position on the belt the code may be fed into the memory section 5 with zero count in count 10. A toothed wheel 16 on the conveyer drive has an associated detector which passes a pulse (representing a unit of length on the conveyer) to the adder 7 so that each word, as it circulates in the loop has its count 10 increased by 1 for each tooth. Each time a word circulates in the loop its count 10 is compared with its destination 11 through decoders 20, 22 and a comparator 23. When they are identical an appropriate bi-stable 24 receives a set pulse to change over so that a solenoid amplifier supplies current to the appropriate gate solenoid to Àdischarge the parcel from the belt. The gate remains open unless the next parcel is for a different destination: the inverted output from decoder 22 is compared with the output from a decoder 21 by a comparator 26, if coincidence is found the gate is shut. The total of parcels sorted and their destinations are recorded on recording equipment 28 associated with photodetector 18 through a decoder 30 and amplifiers 29. The photodetector also operates a timer 31 for controlling a switch-off heavy duty relay 32 to switch off the apparatus if 5 minutes elapse without a parcel being detected on the belt. Instead of a delay line 6 a magnetic core store 30 (if otherwise available) may be used, complete drawing (not shown). If there is no requirement that a gate should remain open until the next parcel is dealt with the control system may be simplified: items 20, 21, 23, 26 are dispensed with, the compliment of the destination inserted in the word instead of a zero count 10, so that overflowing is detected to operate the appropriate gate. Information to the encorder 3 may be by way of electronic character recognition apparatus reading symbolts on the articles being sorted.