Patent GB-806878-A (GB)
Title: Improvements in or relating to value accumulators
Inventor: CARTWRIGHT JOHN ROBERT
IPC: H03K29/00
Filed: 1956-04-06
Abstract: 806,878. Digital electric calculating apparatus. BRITISH TABULATING MACHINE CO, Ltd. April 2, 1957 [April 6, 1956], No. 10562/56. Class 100 (1). Apparatus for summing values in a non- decimal scale which is the product of two integers, includes two value-registering devices operable in the scales of the two integers respectively, each controlling a translating switch network associated with the other device, and means for generating value-representing pulses under control of the translating networks to represent, in decimal notation, the value registered. As applied to a record-card controlled machine, one order of the accumulator operating in a radix of sixteen comprises two multicathode counting tubes 10 and 32 arranged to operate in radices of eight and two respectively. Read-out from this order is to be in decimal form, either true value or complement. Uniformly-timed negative pulses synchronized with the card sensing mechanism are applied to a line 3 and contacts 1 are shifted in response to the sensing of a card perforation to supply to the counting tubes a train of pulses representing the value sensed. If complementary values are to be entered contacts 2 are closed at the beginning of the sensing cycle and the operation of contacts 1 terminates the pulse train. In order to adapt the counting tubes to a radix other than that for which they were designed, the cathode A on which the glow arrives after eight input pulses (starting from zero) is coupled via capacitor 19 and resistor 20 to the grid of a gas tube V1 so as to ignite the latter. The resulting fall in voltage at the anode of V1 is fed back via capacitors 27, 28 and contacts R1a to the zero-representing cathode 11 so as to transfer the glow to this cathode in readiness for the next pulse. Also, the reduced voltage at the anode of V1 is fed 2  via a line 29 to contacts R2a, Fig. 2, and when these are transferred at the " carry " time, a negative pulse via capacitor 30 and diode 31 steps on the discharge in a further counting tube 32 which is arranged to operate in a binary cycle by a similar arrangement; arrival of the glow on cathode B after two input pulses fires a gas tube V2 and the fall in the anode potential of the latter supplies a negative pulse to the zero cathode C so as to return the glow to this position. Carry to the next higher denomination is taken from the anode of V2 on line 43. Carry pulses from the next lower denomination are received on a line 37 and fed to tube 10 when relay R2 is energized. Reading out from the accumulator to punching or other recording means is initiated by energizing a relay R1, thus bringing punch setting magnets 45, 46 under the control of valves V1 and V2 respectively. A commutator 49 operates in synchronism with the recording mechanism, supplying a positive voltage to the cathodes of the tube 10 in turn through a network of translating switches R3a ... R3h, R4a ... R4j. When the cathode taking the discharge current is tested in this way the current is diverted through the common resistor 18 causing the tube V1 to strike and supply current to the punch control magnet 45. This will occur at a time representing the units decimal digit (or the complement) of the value registered. The tens digit, which will be either " 0 " or " 1 ", is determined by test pulses on lines 53 and 54 passing through a translating switch network R6b, R6c, R4k, R41, and the firing of V2 to energize magnet 46. In the translating networks magnet R4 (not shown) is the " carry " magnet of the highest denomination and thus determines whether a true number or complement is to be read out; magnet R3 is energized via a tube V3 when tube 32 is registering " 1 " and modifies the read-out from tube 10 accordingly. Relay R6 is controlled by a relay R5 in the anode circuit of a tube V4 which strikes if the units digit read out is " 9 " or " 8." Instead of multi-cathode gas-filled counting tubes, a known type of electro-mechanical accumulator could be employed.