Patent GB-583973-A (GB)
Title: Improvements in or relating to accounting machines
IPC: G06F7/42
Filed: 1944-08-28
Abstract: 583,973. Electric calculating-apparatus. BRITISH TABULATING MACHINE CO., Ltd. Aug. 28, 1944, No. 16276. Convention date, Aug. 28, 1943. [Class 106 (i)] An electric relay accumulator comprises, for each denominational order, a plurality of accumulating relays settable to represent a digit and a plurality of entering relays settable to represent a digit to be added, three sets of contacts to each set of relays, the first set setting the accumulating relays to represent therein the unit part of the sum of two digits to be added, the second set setting the accumulating relays to represent one more than the units part of the sum of two digits to be added, and a non-carry and a carry connection from the third set of contacts in one order to the first and second sets of - contacts in the next higher order according towhether the sum of the digits is not greater than or greater than 9,- respectively. The circuit for any one denomination is shown in Fig. 5, a number of such circuits being assembled together as in Fig. 6. The principle of the invention is illustrated in Fig. 4, wherein switch arms C, D and the carry and non-carry lines represent sets of contacts in Fig. 5. Keyboard. The keyboard is of the type described in Specification 574,405, the switches closed by the individual keys being shown.in Fig. 5.. Relays. The accumulating relays A1, A2, A4, A8 and the entering relays R1, R2, R4, R8 have values according to the first four terms of the binary progression. The relays each have a number of contacts. The accumulating relays prepare to shift their contacts at energization, the shift taking place at de-energization, as described in entering. relays shift their contacts upon energization and enable them to return to normal upon de-energization. Addition. The first number is set on the keys in the various denominations to close related contacts a and with the add key 25 depressed, and the appropriate entering relays R are energized. Depression of the operating key 26 sets up circuits through the appropriate contacts of the A and R relays and the appropriate rectifiers 52 to energize the relays A corresponding to the amount set up. A readout indicator comprises a number of lamps 36 illuminated according to the number represented by the A magnets energized. Addition of a second number set on the keys takes place in a similar manner the contacts of the A and R magnets, according to whether they are energized or not, determining which A magnets will be energized and which deenergized after the depression of the operating key 26 which traces a circuit from line 34 to wire 53 in the units order. From wire 53 the circuit extends to contacts on its left and right which determine whether the sum of the two digits in that order is less than or more than 9 ; if less than 9, they direct the circuit to non- carry' wire 49, connected to non-carry wire 50 of the next higher denomination ; if the sum is more than 9, the circuit goes to the carry wire 57 and so to the carry wire 58 of the next higher denomination; if the sum is 9, the wires 50 and 49 are connected to the wire 50 of higher denomination. The principles of carry and non-carry are illustrated in Fig. 4, the arms C, D representing the circuits provided by the contacts of the A and R relays. In the higher denomination, circuit is made over either the carry wire 58 or the non-carry wire 50 according to whether the sum in the lower denomination exceeds 9 or not, parallel paths through the rectifiers 52 being provided, whereby the A magnets are set to represent the sum of the digits in the higher denomination or one more than the sum of the digits, respectively. Carry from the units order through the tens order to the hundreds order can take place from wire 53 Fig. 4 arm D, wires 57, 58 arm D of tens order in position 9, wire 57 to wire 58 of the hundreds order. Subtraction. The minus key 25 is depressed and latched to connect the negative line 34 with line 44 to energize the R magnets according to the nines-complements of the amount set on the keyboard. Depression of key 26 then results in subtraction by complementary addition entry of the fugitive one taking place through the '' over 9 " setting D of the highest order, lines 57, 61, 62, 63 to carry line. 58 of the units order. A negative result appears as a nines-complement, and the addition subsequently of a quantity equal to a minus quantity standing on the A magnets brings the register to indicate a succession of nines, the circuit being completed via a series of contacts in each denomination indicated schematically in Fig. 4 by an arm E. As shown in Fig. 6, a switch 67 is closed in the highest order and open in the others, whereby a 9 in the highest order lights a minus lamp 33 to indicate a negative total, while any other number lights the positive lamp. Clearing register. Depression of key 27, Fig. 6, energizes relays CL to lift the related contacts whereby any A magnets whose con. tacts are in set position receive an impulse over their a contacts to shift the contacts to unset position at the release of the key 27. Modification. In Fig. 7, not shown, the rectifiers 52 are omitted, the A magnets have two windings, one controlled by the non-carry wire and the other by the carry wire, and the R relay contacts are duplicated.