Patent GB-576372-A (GB)
Title: Improvements in or relating to adding mechanism for record card controlled accounting machines
IPC: G06F7/42
Filed: 1944-03-29
Abstract: 576,372. Statistical-machines. BRITISH TABULATING MACHINE CO., Ltd. March 29, 1944, No. 5840. Convention date, March 21, 1943. [Class 106 (i)] A record card controlled machine for algebraically adding simultaneously a plurality of multi-denominational numbers, comprises in each denomination a plurality of groups of sub-groups of contacts, settable to represent the digits to be added, an electric network interconnecting the groups of contacts, a circuit or circuits in the network through the set contacts adapted to represent the sum of the digits without carries from a lower denomination, a plurality of carry relays adapted to be operated by one or more of the circuits, to represent the carry to be made from the sum, a sub-group of contacts for each relay, a second electric network connecting each said sub-group of contacts with the first network (except in the lowest denomination) and an electric circuit or circuits through the combined networks comprising a registering magnet or magnets in which the digit of the sum in each denomination is registered. Setting-up. Numbers read from the cards are converted into a four-position code (i.e. expressed in terms of 1, 2, 3 and 6) and set up in relays (shaded in Fig. 1 to represent the three numbers, A=762, B=425, C=819, to be added). Cam-operated contacts F6-9 &c. (L.H. of Fig. 1a), closing at the card positions indicated by their suffix numbers, complete certain circuits through two columns of relays 6AA, 6AAu, &c. (the second being for the units order) closing contacts (Fig. 1) which are held only when sensing brushes LB find a hole in the punched card and establish a maintaining circuit (e.g. main switch 50, line 51, usual card lever LCL1, roller 54, R.H. brush LB, socket 59, L.H. line 100, terminal 60 of group C, thence the circuit shown by heavy line to energize relays shown shaded representing the number sensed-9=6+3). Addition. After completion of the setting-up operation, contacts CC12 (Fig. 1a), close and current passes through groups of contacts (Fig. 1b) A (representing units digit of first number), B and C (representing units digits of other two numbers), and thence through a further group R (Fig. 1c) (representing units digit of the previous total) to set up the units result in relays 1Pu &c. (The heavy line in Fig. 1b illustrates the addition of the units A=2, plus B=5, plus C=9). Each group of contacts A, B and C is controlled by corresponding relays 2Au &c. of Fig. 1 and interconnected so as to perform the required addition. The network at the L.H. of Figs. 1b and 1c is arranged so that relays 1Eu &c. are energized whenever the addition in a particular group necessitates a carry. (The heavy line illustrates the operation of relay 2Eu during the addition referred to above.) These carry relays control an extra group of contacts, Fig. 1c, in the next denomination. Subtraction. A special hole in the card, indicating a negative quantity, is sensed by advanced brushes UB (Fig. 1), and maintaining circuits for appropriate relays AS, BS, CS (centre, Fig. 1a) are established via contacts CC8, 9 or 10 and intermediate relays SA, SB or SC. These relays AS, BS, CS (shown again, dotted, L.H. of Fig. 1a) control groups of contacts so as to set up the complement of the respective digit in the relays 6AA &c. (Fig. 1)- complement of 10 for units digits (necessitating separate relays 6AAu &c.) and complement of 9 for other digits. To account for certain discrepancies in the method of subtraction (e.g. complement of 200 would be set up as 790), relays AS, BS control further contacts (Figs 1b and 1h, not shown) to make the necessary corrections. Total taking. The results set up in the intermediate relays 1Pu &c. (Fig. 1c) are subsequently transferred to relays 1Ru &c. which, besides controlling contacts shown in the upper portion of Fig. 1c, control further contacts (R.H. of Fig. 1a), whereby, when relay T closes contacts T1, current passes via the brush of an emitter 65, rotating in synchronism with printing devices, and the network containing the contacts, energizing the printing magnets 110 at the appropriate times. To prevent energization of unwanted circuits in certain cases, unidirectional devices such as cupric oxide or selenium rectifiers 62 (Fig. 1e) are provided.