Patent GB-589729-A (GB)
Title: Improvements in or relating to record-card controlled accounting machines
Filed: 1945-03-28
Abstract: 589,729. Statistical apparatus. BRITISH TABULATING MACHINE CO., Ltd. March 28, 1945, No. 7880. Convention date, April 1, 1944. [Class 106 (i)] Relates to a record card controlled machine, comprising an accumulator with elements settable to represent the digits 0 to 9, the digits being represented on the cards according to the code shown in Fig. 6. The amount standing in the accumulator is represented by the nines complement thereof, and positive items are added as nines complements and negative items as true numbers. The accumulator, Fig. 2, is driven by a continuously-rotating shaft 14, which is geared to a sleeve 26, carrying a ratchet wheel 27 (not shown), which is adapted to be displaced axially into engagement with one element of the accumulator by a cam-edged wheel 33, mounted on a bell-crank 34. Energization of a magnet 36 unlatches the bell-crank 34, and a spring 37 rocks it into its operative position. The bell-crank is restored either by the energization of a second magnet 70, which unlatches a lever 72, carrying a pin 75, which engages the bell-crank, or when one of three lobes 39, on a cam 38, which is a novel feature of the accumulator, engages an extension on the bell-crank and thus restores it to its unoperative position. The card is sensed by positioning it between a number of brushes 45, Fig. 7a, and conductors 46, corresponding with the columns in the card, separate conductors 47 being provided at the " 5 " positions. Current from a line 51 passes through contacts C4 and 52 to an emitter E, rotating in sychronism with the shaft 14, Fig. 2, and a brush 50 passes over segments 49 and completes the circuit to conductors 46 or 47, where holes occur in the card. The current then passes to either a magnet 36, Fig. 2, or a magnet 70, according to whether the amount represented on the card is positive or negative. In the case of a positive amount a magnet 36 is energized to engage the accumulator element with the driving means, when the brush 50 contacts the appropriate segment, all the accumulator elements being mechanically disengaged by the cam 38 at the time the brush 50 reaches the " 0 " segment (not more than 4 units having been added). In the case of numbers less than 5 (where the nines complement exceeds 4) the magnet 36 is energized a second time to add in a further 5 units, the bellcranks being automatically disengaged by a second lobe 38 of the cam 38. The adding in of this further amount is suppressed in the case of numbers whose nines complement is less than 5. Negative items are represented by a special hole 13, Fig. 6, in the card which, when sensed by a brush 45a, Fig. 7a, causes energization of a relay R3 which conditions the circuit to cause the numbers read from the card to be entered into the accumulator as true numbers. Thus the magnets 36 are energized at the beginning of the cycle to engage all the accumulator elements and the disengaging magnets 70 are energized when the emitter E passes current through holes in the 1 ... 4 positions in the card. Sensing of a " 5 " perforation now causes the accumulator elements to be engaged a second time to add in a further 5 units. " Carries " are added in during a third stage in the machine cycle. Cam means on each accumulator element close a pair of contacts when the wheel passes from 9 to 0, and these latched. A carry impulse is supplied to magnets 36 through these contacts and the elements are disengaged by the third lobe 39 of the cam 38 after the carried " ones " have been added. The circuit includes read-out and restoring means, including rotary brushes 74 (shown diagrammatically in Fig. 7a), turning with the accumulator elements and bridging contacts 85 and common conductors 86 according to the amount standing in the accumulator. Timed impulses through contacts C5 .. C9 and network 91 &c. control magnets 36 and 70 to bring the accumulator to the nines complement zeroized condition and, by closing switches 87, 88 current may be passed to magnets 80, 81 controlling printing mechanism such as that described in Specification 584,242.