Patent GB-740156-A (GB)
Title: Improvements in magnetic record controlled sorting apparatus
Inventor: FORMBY JOHN ALBERT
IPC: G06F7/24
Filed: 1951-06-26
Abstract: 740,156. Statistical apparatus. FORMBY & CO., Ltd., J. June 20, 1952 [June 26, 1951], No. 15181/51. Class 106 (1). A magnetic recordcontrolled sorting apparatus, for sorting or grouping data comprising items each consisting of a group of the same number of symbols recorded on a magnetic surface of a transmitting record member sequentially, comprises a continuously-moving reading magnetic record member on which the symbols are magnetically recorded, reading means to transmit predetermined recorded symbols, selective means adjustable to respond to any predetermined one of the symbols of an item in order to transmit all those items and only those items wherein the said predetermined symbol has a predetermined value to which the selective means is adjusted to respond, the selective means being characterized by an advanced, or upstream, magnetic scanning means which controls the functioning of, and is distinct from, the magnetic transmitting means so that the whole grouped item is selected or not selected according as the predetermined symbol is present or not. Fig. 1 shows a set of twenty-four transit drums 1 of plastic material covered with magnetic tape material having vertical axes and driven through helical gears 2 from horizontal shafts 3 which are geared by helical gears 4 to a third horizontal shaft 5 driven through 2: 1 ratio helical gears 6 by a vertical shaft 7 which is in turn driven through further gearing by a motor 10. A further similar apparatus may be kept in synchronism at a distance by means of Selsyn motors of known type. The drums are associated with lead-screws on which ride mountings 17. Each mounting has a half nut in contact with the screw and carries a set of magnetic heads comprising an erasing head 19 having a track 0.1 inches, and a pair of recording or reproducing heads 20 having tracks 0.055 inch wide. The lead-screws are driven from the drum shaft by sprockets 21 and chains 22. The heads 20 are spaced apart at a distance exactly equal to an items length. At each end of the drum is a microlimit switch to reverse the direction of travel. A switch 105, Fig. 7, distinguishes between transmitting and receiving modes of operation. One of the heads 20 associated with the drum 12 is connected to the advanced transmitting amplifier 106 while the other is connected to the main transmitting amplifier 109. The output of the advanced transmitting amplifier 106 is applied to a set of frequency discriminating networks each consisting of an adjustable resistance 111 and a parallel circuit 112, the inductance of which is provided by a miniature coil with an iron dust core. Each circuit is tuned to a distinct frequency according to the ten basic symbol values by means of tunable iron dust core. The ten basic frequencies preferably range from 9000 cycles to 18,000 cycles per second. A ten-point junction box 114 is provided with ten switches 115 in parallel each connected to a thyratron tetrode valve control grid 117, Fig. 7. The shield grid is connected to the rotor of one of the switches 68. Thus by setting the two switches associated with each thyratron, a particular symbol value is selected in each case. The cathode of each thyratron has a load resistance 119 connected to a second thyratron control grid 121. The cathode of any of these thyratrons may be connected to the transmit side of a channel of the transmit-receive switch 105. Thus each of the thyratrons 121 may be regarded as a gate valve which admits only the required items to the transmit drum and provides in association with the clutch that these items are recorded in compact form. The selective process may be continued until all the items have been transmitted to one or other of the transit drums. The process of transmitting from a drum 12 to transit drums may be ended by operating a manual switch when a magic eye indicator associated with the transmitting amplifier shows that there is no more matter to be transmitted, or it may be ended automatically by the action of limit switches, one cutting off the amplifier and the other cutting off the power supply to the main motor. If the receiving drum contains, for example, groups of items in account number order and it is desired to record the opening balance of each group in the space immediately preceding the group, this can be done from a set of opening balances recorded on a space transit drum, so that one item only from each group of items is transmitted from the record means to the additional recorder. Each item consists of a definite number of symbols followed by a gap of definite length, each symbol consisting of a magnetic pattern of characteristic frequency which may be modulated by a second characteristic frequency, each symbol occupying the same length of magnetic track. Null signals are represented by a special frequency provided. The selective device is such that it will select only those items in respect of which symbols having prescribed positions within the items have prescribed values. Thus, for example, the device may be set to select only those items in which the third symbol has a value of 7. Each item selected from a transmitting magnetic member is reproduced on a magnetic transit recorder without gaps. The transmitting and receiving members are identical so that by repetition of the process, erasing records no longer required, and operating each time on a difference symbol position within the item, the item may be sorted into any desired sequence. Items of two distinct categories may be collated on the receiving member, for example, when item relates to accountancy transactions, the groups of the receiving member may represent items in account number order and it may be desired to associate with each group the opening balance of that account by recording it in a gap following or preceding a group.