Patent GB-1023368-A (GB)
Title: A control system for loading a conveyor
Inventor: GAULT VINCENT ARTHUR
IPC: B65G47/50
Filed: 1964-12-18
Abstract: 1,023,368. Conveyers. MULLARD Ltd. Dec. 18, 1964, No. 51567/64. Heading B8A. A control system for controlling the loading of articles on to an endless conveyer A from a plurality of discharge points 1, 2, 3, 4 for transport to a specified receiving station 6, 7, 8, 9 along a tilted band, conveyer B as described in Specification 1,022,840, ensures that an article is only loaded on to the conveyer A when there is a clear space for it. Bundles of newspapers, each requiring 4 feet of the 100-foot path on conveyer A (which moves at 180 feet per minute), are supplied to each point 1, 2, 3, 4. Associated with each point is a light L K  (K=1, 2, 3, 4) which shines on to a detector D K  positioned at R K . A transducer 11, Fig. 2 (not shown), in conjunction with a toothed wheel 12 attached to a roller at one end of the belt A produces a pulse for each 2 inches movement of the belt A. The control system comprises a " write-in " section 13 common to all four discharge points, a photo-electric detection section 14 in respect of each discharge point, a store section comprising a memory 15 and an information section 16, which store is common to all discharge points, a monitoring section 18, a gating section 19, an inhibit section 20 and an operating section 21 which are each provided in respect of each discharge point. The " write-in " section 13 comprises an encoder 24 which operates on an AND function and produces a binary code output signal characteristic of the bundle at a discharge point and includes information as to which discharge point 1, 2, 3, 4 a bundle is being released and which of the receiving points 6, 7, 8, 9 it is destined for. The scanner 25 scans continuously in rotation the discharge points 1, 2, 3, 4 to see if information is waiting to be encoded. The information section comprises a temporary store 26 which receives the data from the encoder 24 and passes it to a register 27 when a vacant " word " appears in the register 27 and is detected by a word detector 28. The register 27 is in a closed loop with a memory 15, comprising a wire delay line 30, and an adder 29. The word length is 14 bits (see Specification 1,022,840). All words are stored in the memory 15 except one which is in the rest of the loop and the words are continuously circulated by virtue of the control section 17 which comprises a 100 kc/s. clock and a distribution section 38. Each 14 bit word is split into three sections: 1 bit in a section 33, either a " 1 " to indicate an occupied word, or a " 0 " for a vacant word; a section 34 of 10 bits including a count of the number of 2-inch distances moved by the belt A and thus a measure of the distance an object discharged on to the belt A has moved on the belt A; and a section 35 of 3 bits which is the data provided by the encoder 24 giving the identity of the bundle. The monitoring section 18 comprises three decoders 40, 41, 42; 40, 41 monitor the count 34 and 42 monitors the identity 35. The decoder 42 is not relevant to the loading of the conveyer A but transfers data to a control system described in Specification 1,022,840 when a decoder 43 monitoring the count 34 indicates a maximum count, i.e. the bundle is at the end of conveyer A and about to be transferred to the conveyer B. The decoder 40 feeds its output into a reverse trigger section 44 of the gating section 19 while the decoder 41 feeds its output into a forward trigger section 45. Both trigger sections 44, 45 each have an input from the transducer 11 and each is a one-stage counter. The inhibit section 20 comprises a reversible counter 46 fed with reverse stepping signals through an inverter 47 or forward stepping signals through an OR gate 48. Release gates 51 receive a " release " signal over line 52 to open or an " inhibit " signal over line 53. The operating section comprises amplifiers 54 to operate solenoids connected with the release mechanism of a discharge point 1, 2, 3, 4. When a bundle is ready to be discharged on to the conveyer A data is fed into a vacant word in the register 27 and this word is circulated through the delay line 30. Each occupied word circulated has its count 34 increased by unity for each pulse from the transducer 11 and the particular word in the register is monitored to ascertain the position of the associated bundle on the belt A. Inhibit or release signals to the operating section may thus be generated to ensure that a bundle is only fed to the belt A if there is a vacant space for it, since the reversible counter 46 associated with a particular discharge station is set forward one unit for each bundle obstructing discharge and back one unit for the requisite number of pulses from transducer 11 to clear one bundle past the station. Instead of the delay line 30 the memory may comprise a, or part of a, magnetic core storage device which is constantly monitored.