Patent GB-847480-A (GB)
Title: Improvements in accounting machines
IPC: G06F7/52
Filed: 1956-12-21
Abstract: 847,480. Digital electric calculating apparatus; statistical apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 21, 1956 [Dec. 23, 1955], No. 39118/56. Class 106 (1). [Also in Group XVI] A card input accounting machine has an arithmetic section and a magnetic drum such that data from a record card is read on to the magnetic drum and is processed from the drum while data from the next card is being read on to the drum. The record cards are of the conventional 80-column type, an alpha-numeric character being represented by holes punched in a single column. Data is sensed column by column by brushes and translated in the machine to a seven bit code comprising two zone bits, four binary bits and a redundancy bit. Decimal digits are represented in the 1, 2, 4, 8 code. Data from successive record cards is loaded into alternate tracks of the magnetic drum, one track to each card, one address on a track to one column of the card. The arithmetic operations of addition, subtraction and multiplication are possible. Machine operation is controlled by a plugboard and the output is in the form of a printed record (see Group XVI). The operation of card listing, i.e. printing data in specified columns of the output record sheet, is necessary to initiate any arithmetic operation although the actual printing on the record sheet may be suppressed. Group control of cards is by comparison of data on the card being read by the brushes with data from the preceding card taken from the magnetic drum. The magnetic storage drum carries six storage tracks: card track 1, card track 2, counter track 153, temporary storage track 154, with which is associated a permanent magnet erase head 161, multiplicand track 157 and partial product accumulator tract 151 also with a permanent erase head 162. Each storage track has 83 7-cell addresses and an additional area equivalent to 19 cells for synchronization purposes. There is also provided a clock track 163 comprising 600 teeth of which 581 are magnetized. For most purposes only 80 of the addresses on each storage track are used corresponding to the 80 columns of a record card but the machine time of the 21 cells 561 to 581 is required to complete operations started in cells 79 and 80. The counter track may be considered as being divided into 10 counter groups each comprising 8 addresses. These groups store the result of arithmetic operations. Machine timing.-The signal induced by the magnetized teeth of the clock track read head 164 are transmitted to a sync amplifier 428 generating a train of A pulses on lines 429. The amplifier also includes an inverter stage driven by the A pulses and of which the output is B pulses 180 degrees out of phase with A pulses transmitted on line 430. A pulses issue in the first half of a time interval, B pulses in the second half. A pulses are mainly utilized in controlling and timing the writing of information on the drum tracks. There is also provided an address device (Fig. 13B) comprising three conventional ring circuits, a 7-stage ring 432, an 8-stage ring 433 and a 10-stage ring 434. Each stage consists in a conventional trigger circuit which is considered to be on when the left-hand side is conductive. The 7-stage ring corresponding to the seven cells in an address, is advanced one stage each 16 microseconds by B pulses applied on line 430A, the trailing edge of each B pulse switching off the trigger which is on. When a stage of a ring is on the high potential of its right plate is applied through an associated cathode follower to an output conductor 440. When the 1 of 7-stage trigger is on the zone 1 cell of an address on the magnetic drum is passing the clock track read head. The 8-stage ring is similar to the 7-stage ring and the triggers of the ring are switched by the potential drop on the right plate of the 7 of 7 trigger as it is switched off being transmitted on line 443 to the trigger inputs. The output of the first trigger is named a 1 of 8 signal. The 10- stage ring is not closed and is advanced by the switching of the 8 of 8 trigger. The time between the 1 of 10 trigger being switched on and the 10 of 10 trigger being switched off is that necessary for 560 address cells (80 addresses) on the magnetic drum to pass a reference point. The outputs of the 8-stage ring triggers appear on lines 445 (Fig. 13D) and each line is connected to one side of ten diode units 452 (two only shown for each line 445). As shown the outputs of groups of four of the diode units are connected in common through a resistance to the outputs of 10-stage ring triggers. A diode unit is conductive when the 8-stage ring output and the 10-stage ring output are applied simultaneously and the output of the diode unit is led to a reading exit position hub 364 on the plugboard. There are 80 such hubs and each is activated by a combination of an 8-stage ring trigger and a 10-stage ring trigger being on. Thus hubs 1 to 8 are activated in turn by the combination of the 1 of 10 trigger and the 8 triggers, 9 to 16 by the 2 of 10 trigger and the 8 triggers. The outputs of the diodes are also led to the contacts 362 of the card feed emitter. The outputs of the 8- stage ring are led to counter position exit hubs 1052, and of the 10-stage ring to counter group selection hubs 1294. During a full rotation of the magnetic drum 581 teeth pass beneath the clock reading head. At the end of the rotation the 3 of 8 and 7 of 7 triggers are on, the 1 of 10 trigger not being on since the 10-stage ring is not closed, and it is necessary to resynchronize the trigger rings with the clock teeth of the drum. During the passage of the 19 unmagnetized teeth past the clock read head the potential on the B line 430A is applied to one input of AND unit 454, the other input being conditioned by a power source 455. The output is applied to a zero trigger 458 switching it on. As the first tooth of the clock track rotates under read head 164 conductor 430A shifts negative switching the 7 of 7 trigger off, which switches the 1 of 7 trigger on, and also deactivates AND unit 454. The negative shift of the output switches trigger 458 off and the negative shift of the right plate of the trigger in turn is applied to the 1 of 10 and 1 of 8 triggers switching them on. The switching off of the 7 of 7 trigger turns off the 3 of 8 stage but the switching on of the 4 of 8 stage is suppressed by the negative shift of the trigger 458 applied to the right plate of the 4 of 8 trigger. Through the action of the zero trigger 458 an alternate drum cycle trigger 465 is switched between on and off positions on alternate drum cycles. An associated conductor 467 is at low potential during one drum cycle and at a high potential during the succeeding cycle. The emitters.-The machine drive rotates a shaft 299 (Fig. 19) which carries six rotators each comprising a pair of arms 323, 327 which carry contacts brushing corresponding emitter plates. On each side of each emitter plate are 40 conducting segments 320 arranged in an arc and a corresponding common contact 321. Contacts 326, 331 carried by each arm of the rotator make an electrical connection between a segment 320 and the common 321 as the arm passes. The arms are so arranged that when one arm has swept the 40 segments on one side of the plate the other arm then sweeps the segments on the other side of the plate. Certain of the wiper arms carry additional contacts which lag the contacts 326 by one segment 320. The segments 320 are connected to hubs on the machine plugboard. The 80 segments correspond to the 80 columns of a record card and define corresponding columns in the print record machine output on corresponding addresses in the storage tracks. The activation of the plug hub is utilized in directing machine operations. The six emitters are called the print position control exit emitter, the counter read out emitter, the counter + and - emitter, the counter entry emitter and print position exit and entry emitters. In addition (Fig. 2) there is a card feed emitter plate 363 which carries 80 segments 362 swept by an arm 357. Each segment is connected to a reading exit hub and the arm carries two contacts 358A, 358B electrically commoned. Card feed.-Cards are stored in a hopper 368 (Fig. 2) and a rocking shaft 382 moves an arm 386, meshing with a rack 389, initially anticlockwise. A picker knife 392 mounted on rack 389 moves the bottom card of the stack into engagement with card feed rollers 393, 394. The lower roller 393 is spring urged against the upper and the presence of a card between the rollers causes movement of roller 393 which is transmitted by arms 412, 414 to close contacts CLC-1 and CLC-2. An insulating member 417 carries a series of brushes 418 guided by grooves in roller 393 into contact with roller 394 which is a conductor. Roller 394 is energized through a brush 419. The shaft 382 is driven from shaft 371 which carries cams actuating card feed contacts. A relay is provided which operates when a card is jammed to stop the machine. Card sensing is effected at the rate of one column of the card for each revolution of the drum. As column 1 of the record is positioned beneath the brushes the contact wiper 358 of the card feed emitter is contacting the first segment of the emitter and the positive pulse emitted on the reading exit hub 362 (Fig. 13D) is transferred through wiper 358, common 361, closed contacts R13G of a relay energized by operation of card feed contacts line 509, cathode followers 510 and 511 (Fig. 13A) to the conductive roller 394. Let A be punched on column 1 of the card. This is represented by holes punched at the 12 and 1 index points. The circuit continues through index point 12 brush OR units 517 and 520 respectively to one input of AND units 519 and 521. The other input of AND unit 519 is conditioned by a 1 of 7 signal so that at 1 of 7 time a signal from AND unit 519 issues through OR unit 528 to a l