Patent GB-537858-A (GB)
Title: Improvements in or relating to calculating machines
IPC: G06F7/46
Filed: 1939-10-04
Abstract: 537,858. Record-card-controlled d statistical machines. BRITISH TABULATING MACHINE CO., Ltd. Oct. 4, 1939, Nos. 27222, 27223, and 27224. Convention dates, Oct. 5, 1938, Nov. 25, 1938 and Dec. 27, 1938. [Class 106 (i)] A calculating machine for handling amounts of non- uniform rotation has means for reading and feeding cards each bearing a non-uniform amount, means to register a pre-calculated coding factor(s) appropriate to the non- uniform rotation, coding mechanism which, after card reading, automatically multiplies each digit of the non-uniform amount by the proper coding factor and sums the partial products to give a uniform amount exactly equivalent to the original non - uniform amount, calculating mechanism which then automatically multiplies, or divides, this equivalent uniform amount by a second uniform amount, and means to record the final result with uniform rotation. E.g. ú5 12s. 6d. is converted to 1,350 pence and multiplied by 3 to give a result of 4,050 pence ; or ú5 12s. 6d. is converted to 1,350 pence and divided by 2 to give 675 pence. By the use of decoding factors the uniform result may be converted to a non- uniform amount i.e. 4,050 pence into ú16 17s.6d. By using de-coding factors which take into account the rate of exchange, an amount in British currency may be converted into an amount in a foreign currency. Alternatively, a decimal amount may be converted into a non- uniform amount. The coding and decoding factors are punched in special cards which are inserted in, and read by, special electrical pin-boxes, Figs. 18-19 (not shown), and X-1, X-2, &c. Figs. 21c and 21e (not shown), whereas the original non-uniform or uniform amounts to be dealt with are punched in cards in the usual manner and read by electric contact brushes 313, Fig. 23a (nto shown), which are plugged to sockets 316, Fig. 23a (not shown) and sockets 315 ML Fig. 22b (not shown). The above method of calculation is substantially the same as that set out in Specification 491,066. The present machine is generally similar to that described in Specification 532,109, to which particular reference is also made for the multiplying and dividing operations. The comparing units CU, Fig. 1a (used in division), the card feed devices, and the doubling read-out devices used in building up multiples of a multiple card are as set forth in Specifications 405,031, 456,367 and 523,652 respectively. Multiplication of a non-uniform number by a decimal number (non-uniform result)- e.g. ú5 16s. 7d. by 25.8. Figs. 28 and 33. The multiplicant unit ML, Fig. 1, consists of six accumulators as in Specifications 532,109 and 456,367, the first three accumulators having doubling read-out means. The amount is initially entered into five of the six accumulators and thereafter by transfers from various read-outs the multiples from 1 to 9 of the multiplicand initially entered are built up on the read-outs as in the prior cases. When the machine has started the decimal amount 25.8 is entered into the unit ML and build-up proceeds ; and 7 pence is entered into accumulator, RD, Fig. 1a. Next ú5 16s. is entered into register MP and thereafter accumulator LQ is reset to zero. At the next stage, ú5 16s. is coded in a multiplying operation in which coding factors of 240 and 12 are read from pattern cards in the pinboxes, Figs. 18-19 (not shown), and treated as multiplicands and in which ú5 16s. is treated as multipliers. ú5 16s. is thus coded to pence in several cycles and accumulated in RD, the amount in RD is then transferred to LQ ; and the register MP is reset to zero. RD is next reset and the amount in LQ transferred to MP. LQ is then reset. The register MP now holds ú5 16s. 7d. expressed in a decimal rotation, viz., as 1,399 pence. A further, regular, multiplying phase now takes place in which 1,399 is the multiplier and 25.8 the multiplicand. This phase is as in Specification 532,109 and the final product 36094.2 pence appears in accumulator RD, with accumulators ML and LQ and register MP reset to zero. At the next stage, division occurs as in Specification 532,109 with decoding factors of 12 and 240 read from cards in the special pin boxes and entered into the comparing units. Dividing by 240 occurs first and after the number of pounds is found, the remainder is divided by 12 to give the number of shillings and the pence remainder. The final result ú150 7s. 10d. appears in the accumulator LQ. This result is then punched in the original factor-bearing record card. The various phases for the above and similar calculations are separately traced in detail through the circuit diagram, Figs. 21c ... 21f, 22b ... 22f, 23a ... 23f, and 24 (all not shown). The circuits are also traced for specific examples of the following calculations, viz. (1) dividing a non-uniform number (ú99 19s. 6d.) by a decimal number (2.2)-Figs. 29 and 34 (not shown) ; (2) conversion of a non-uniform number to a decimal number (British currency to U.S.A. dollars)-Figs. 30 and 35 (not shown); (3) conversion of a decimal number to a non- uniform number (U.S.A. dollars to British currency)-Figs. 31 and 36 (not shown) ; and (4) conversion from one non-uniform rotation to another (Indian currency to British currency), Figs. 32 and 37 (not shown). Means are provided for determining the number of decimal places in a result and for approximating a result, e.g. to the nearest penny or cent. A modified circuit diagram is described in which unnecessary operations are omitted for simple calculations. In a second modification for conversion of a non-uniform number to a decimal number (see (2) above), since only multiplication is involved, the machine is simplified by omission of all the dividing means, including the comparing units.