Patent GB-497039-A (GB)
Title: Improvements in or relating to calculating machines for performing division
IPC: G06F7/46
Filed: 1937-06-11
Abstract: 497,039. Calculating-apparatus. BRITISH TABULATING MACHINE CO., Ltd. June 11, 1937, No. 16293. Convention date, July 8, 1936. [Class 106 (i)] A machine for performing division analogous to mental long division comprises means for calculating and registering a standard series of multiples of the divisor, comparing means for comparing the appropriate portion of the dividend with each of the multiples concurrently to determine which is the largest multiple that is not greater than said portion, means for entering the digit corresponding to the said multiple into a quotient register, and subtracting means for subtracting the said multiple from the dividend to obtain a remainder that constitutes the dividend for the next step. The invention is shown applied to a record card controlled machine having a divisor unit DR, Fig. 1, and a dividend and quotient unit DDQ with drive shafts 12 operated by a motor M that drives an A.C.-D.C. generator 132. A shaft 22 drives the card handling and reading and punching sections of the machine which sections are similar to those described in Specifications 362,529, [Group VIII], and 405,031. The machine is also provided with a plurality of cam contacts CC, FC, impulse distributers 15, 16, and a set of impulse emitters 17 ... 21. The divisor unit comprises five separate accumulators DR-1, DR-3, DR-4, DR-7. and DR-9 shown diagrammatically in Fig. 13. The unit DDQ comprises one large accumulator for registering the dividend and for registering the quotient in the upper part. The accumulator units, which are similar to the counters described in Specification 483,021, are mounted on plates 27, Figs. 4 and 5, adapted to be inserted into the machine to couple the gear wheels 25 with constantly rotating gear wheels 24, the coupling being under the control of the counter electromagnets 45, 49. The accumulators are each provided with a readout mechanism comprising a brush assembly 76 and a set of co-operating contact segments 78 and a common segment 79 in an insulating moulding 77. The segments are connected to terminal contact points 83 by means of wires 81. The accumulator DR-1 is provided with a multiple read-out mechanism whereby once, twice or five times, the amount may be read out; the accumulators DR-3, DR-4 are provided with single and doubling read-out mechanisms; the accumulators DR-7, DR-9 have single read-out mechanisms. To determine the number of places in the quotient, a mechanism, shown diagrammatically in Fig. 2a, is provided, which comprises ten commutators with a manually settable brush assembly 105 co-operating with contacts 110, 111, arranged in the circuit connections. Operation. Upon a card entering the reading section of the machine the advance brushes 101, Fig. 2, read the divisor and dividend and selectively control the entry of these factors into the accumulators DR-1, DR-3, DR-7, and DR-9, and the accumulator DD respectively. During the following cycles multiples of the divisor are calculated and entered in the appropriate accumulators as shown in Fig. 13. After the multiples are set up a comparison of the left-hand portion of the dividend with all the multiples is effected and the machine ascertains which is the highest multiple that is less than or equal to the left-hand portion and then proceeds to subtract this amount from the dividend by adding its complement and correcting for the " fugitive one." At the same time the digit value of the multiple selected is entered into the highest denomination of the dividend accumulator DD. Further comparing and quotient entry operations then ensue. Following the final operation determined by the quotient place mechanism, a further operation is initiated to effect the punching of the quotient and remainder on the card and subsequently the resetting of the various parts. Specifications 456,367 and 456,368 also are referred to.