Patent GB-678299-A (GB)
Title: Improvements in or relating to calculating machines
IPC: G06F7/46
Filed: 1949-10-12
Abstract: 678,299. Digital electric calculating-apparatus. BRITISH TABULATING MACHINE CO., Ltd., and KEEN, A. J. Sept. 20, 1950 [Oct. 12, 1949], No. 26194/49. Class 106 (i). Apparatus for converting a value in pence into pounds, shillings and pence comprises an accumulator having read out commutators and electrical circuit dividing networks whereby one-sixth the value registered on the accumulator neglecting any remainder may be subtracted from the said value and also a further dividing network whereby half the resulting five-sixths value as registered in the hundreds and higher denominations may be read out as the units and higher denominations of pounds, respectively. The apparatus is for use in a multiplying or dividing machine, such as is described in Specification 532,109, for converting a product or quotient in pence to sterling. The pence amount p to be converted is registered on an accumulator having associated with each order, except the units and tens, five commutators A, B, C, D and E. The tens order has commutators A, B, C and D and the units order has commutators A, B and D. The conversion takes place in three cycles. During the first cycle, contacts Rlla of a relay R11, operated under cam control, complete circuits in turn through a sensing commutator rotated by the machine drive, the common segments of the commutators A and B and certain of relays R4, R5, and R12-R23, depending upon the number registered in the accumulator. The operated relays are maintained in operation by holding circuits including cam-controlled contacts C3 and normally-closed relay contacts R28a in parallel. Relays R24-R27 are also energized through the holding circuits of certain of the other relays. At the end of this cycle, a circuit network has been established including the relay-contacts and commutators which enables the complement of p/6 to be read out. This amount is added into the accumulator during the second cycle so that p/6 is, in effect, subtracted from p, leaving 5/6 p on the accumulator. During this second cycle, a relay R2 is energized under cam control. Its contacts R2a complete a circuit through a relay R1, the contacts of which connect the clutch magnets of tens and higher orders of the accumulator to the common segments of the associated commutators C and the clutch magnet of the units order to the common segment of the associated commutator B. An emitter E1 produces timed pulses which pass through the network to the clutch magnets to perform the addition of the complement ofp/6. In producing the quotient p/6, the remainder, which cannot affect the pounds or shillings values, is ignored. It is shown that if the units digit of p/6 is even, the units digit after the addition of the complement of p/6 is the correct pence value. If the units digit of p/6 is odd and the remainder is less than 4, then the correct pence value is obtained by decreasing p/6 by one before subtracting this amount, and this is done by the circuit network. If the remainder is 4 or 5, the pence value of the final amount is 10d. or 11d. and the circuit is so arranged that at the end of the second cycle, the units digit registered is 9. This is achieved by the relays R4, R5, the first of which is operated when the remainder is 4 and both of which are operated when the remainder is 5. The relay contacts R4a-R4f prevent the subtraction of one from the quotient which normally occurs when the quotient is odd, and the relay contacts R5a when operated, prevent operation of the carry magnet R3 through the operated relay contacts R2b during the second cycle, which normally ensures that the true complement and not the nines complement is added. During the final cycle, a relay R29 is energized under cam control and its contacts R29a complete a circuit through the relay R28 so that, near the end of the cycle, the cam-contacts C3 and the operated contacts R28a open the holding circuits of the relays energized during the first cycle. The contacts R29a also enable certain circuits to be completed through the thousands and tenthousands commutators D and relays 30, 31, depending on the number registered. A second emitter E2 is then operated to produce timed pulses which pass via the commutators D, E to lines 8 of the sterling denominations at times corresponding to the sterling values. The pounds are obtained by dividing the amount registered by two and reading with a twocolumn shift downward ten shillings is read if the hundreds digit is odd; unit-shillings are read directly from the tens order ten-pence is read if the relay R4 is energized by virtue of the operated contacts R4t; and unitpence are read directly from the units order except that, if this order stands at 9, the digits 9, 0 or 1 are read depending on whether neither of the relays R4, R5 is energized, or the relay R4 is energized alone, or both of the relays R4 and R5 are energized.