Patent GB-501538-A (GB)
Title: Improvements in or relating to multipling machines
IPC: G06F7/46
Filed: 1937-08-31
Abstract: 501,538. Calculating - apparatus. BRITISH TABULATING MACHINE CO., Ltd. Aug. 31, 1937, No. 23838. Convention date, Sept. 4, 1936. [Class 106 (i)] A multiplying-machine comprises means for calculating in succession the products of the multiplicand and successive ascending powers of two, means for calculating in succession the quotients correct to the next lower integer of a multiplier divided by successive ascending powers of two, which means are arranged to obtain concurrently the product and the quotient related by and to the same power of two, a product accumulator and means operable to determine whether each quotient is odd and to enter, when the quotient is odd, the related product into the accumulator. The multiplier may be subdivided into two or more sub-multipliers each constituted by a group (for example, two) of adjacent digits of the multiplier, the multiplicand being multiplied by each submultiplier concurrently and the sub-products so formed " gathered " and added together to give the final product. Any product of a number y may be expressed as the sum of a discontinuous series each term of which is the product of a power of 2 and y. Thus the following identities are true of 197y : The invention is shown applied to a machine of the Hollerith tabulating type with the usual card-feed mechanism, accumulating mechanism, printing mechanism, and reset mechanism. The machine described is provided with three accumulators A, B and C, for two figure multipliers of a six denominational multiplier, with a multiplicand accumulator MC for a two-figure multiplicand, and with three accumulators 1, 2, and 3 for summing the sub-products and the final product. The read-out mechanism for the accumulators MC, and 1, 2, and 3, comprises as shown in Fig. 7, a pair of electrically connected brushes 40 carried by and insulated from a driving gear 39 and cooperating with a set of ten conducting segments 41 and an arcuate strip 42. The read-out mechanism for the accumulators A, B, and C instead of having ten segments is provided with four segments 41a, Fig. 12, corresponding to pairs of digits, and the gear 39 drives another gear 39a actuating a pair of brushes 40a cooperating with segments 41b arranged at the odd digit positions and a conducting strip 42b. The units denomination of each of the accumulators A, B, and C is provided with a carry pawl 108, Fig. 13, that co-operates with a latch 109 controlled by an electromagnet 110 for the purpose of effecting a " fugitive one " entry. Circuit arrangement and operation. In the circuit diagram, Figs. 1, 2 and 3, cams L operate only during the card feeding cycles, cams TP operate only during the total printing and reset cycles while cams CR and the emitters E are in constant operation. Assuming that cards are being fed to the machine, circuits will be completed through the holes representing the factors and the brushes UB. A multiplicand entering circuit, Fig. 3, extends from line 90 contacts CR1, card lever contacts UCL2, a brush UB, plug connection 91, closed relay contacts H2 and a magnet 32 of the accumulator MC. Similarly multiplier circuits, Fig. 1, are completed through relay contacts H3 and plug connections 92 to the magnets 32 of the accumulators A, B, and C. The doubling circuits for the MC accumulator comprise relay contacts D1 and connections 95, 97 to plug sockets 96, 93 of the read-out mechanism and magnets respectively. The sockets 96 are connected by leads 100 to the contacts of relays 1T, 2T and 3T and through leads 101 to the magnets of the accumulators 1, 2 and 3 for transferring the amount on the accumulator MC to one or more of the accumulators 1, 2'and 3. The amounts on accumulators 1 and 2 can be gathered in accumulator 3 by connecting leads 102, 103, through the contacts of relays 1G, 2G and leads 104. 105 to the magnets of accumulator 3. Printing of the amount on accumulator 3 is effected by connecting leads 106 through contacts of relay P and leads 107 to the printing magnets 58. Halving circuits for the read-out mechanism of the accumulators A, B and C, are shown in Figs. 1 and 2. The wires 115 from the emitter E1 are connected by wire 116 to the contact studs 41a for the tons denomitmtion and connected by wires 120 through one or other set of contacto K1, K2 of a ralay K to the contact studs 41a for the units denomination. The relay K is energized when the tens digit is odd and is held energized by a holding relay M. The units contacts 41b control the transferring relays 1T, XT and 3T and a relay N. By this arrangement halving is effected by adding the complement of half the number ; if the number is even the amount added is the nines complement of half the number plus the " fugitive one " ; if the number is odd the complement of half the next higher number is taken and no " fugitive one " has to be entered. As the relay N is not energized when the number is even its contacts N1, N2, remain in the position shown so that the magnet 110 is only energized to insert the "fugitive one " if the next cycle is a doubling cycle when relay D is energized and contacts D2 and D3 are closed. The sequence of controlling cycles is under the control of an electromagnet 136, Fig. J, which operates a ratchet device 134, 137 to step a brush 132 over a contact segment 130 and contacts studs 131. During entering cycles the brush 132 is in the position shown in Fig. 1, and the contacts of relay F are closed so that when cam contacts CR5 close the brush 132 is advanced to energize relay D to permit entries to be transferred from the read out devices of the accumulators MC, A, B and C to the magnets of the same accumulator. Subsequently the relays 1G, 2G and P are energized to gather the amounts and print the final result whereupon the cam contacts TP2 operate to energize the reset magnet 139 to restore the brush 132.