GB1172843A - Improvements in or relating to Calculating Machines. - Google Patents

Abstract

1,172,843. Electronic keyboard calculators. BELL PUNCH CO. Ltd. 23 March, 1967 [31 March, 1966], No. 14300/66. Heading G4A. In an electronic calculating machine having a ten-key digit keyboard, a visual register comprising a plurality of pulse-counting stages connected to visual display means and a store register also comprising a plurality of pulse counting stages, means are provided responsive to depression of an interchange function key to interchange the contents of the two registers a digit at a time. As shown (Figs. 4 and 4a), successive operations of selected ones of the digit keys 11a of an electronic keyboard calculator (Fig. 1, not shown) cause corresponding numbers of pulses to be fed by way of line 28 into successive stages R12-R1 of a visual register 29 the contents of which are displayed by means of number-indicating tubes 6 (Fig. 1, not shown). Stages R13 and VDPC of the register 29 are used respectively for overflow and decimal point position counting. The particular stage to which a digit is fed is determined by coincidence in timing of a pulse t12 from a multicathode timer circuit 18 (Fig. 3, not shown) with one of pulses T1-T12 from a further multicathode timer circuit 15 (Fig. 3, not shown). In order to interchange the contents of visual register 29 with one of two store registers 38, 39, as selected by a switch 37, successive corresponding stages of the two registers concerned are counted up by groups of ten pulses originating from line GD at gates 41 and 125 and carry signals CO1, CO2 emitted from carry store circuits 33, 30 as respective stages of the register pass through the zero condition are used at gates 129 and 130 to detect which of the digits stored in said corresponding stages is the greater, to set a bistable circuit 131 accordingly and to cause a buffer stage 135 to store their numerical differences. Immediately after the counting up of each respective pair of corresponding stages by a first group of 10 pulses, a second group of 10 pulses is counted out. By means of gates 34 and 132 to which the output of the bi-stable circuit 131 is applied and the buffer stage 135 which is counted up by the ten pulses and the output B of which changes the polarity of the output y when the zero condition B = O is reached, a number of pulses equal to said numerical difference is fed to the stage storing the lesser of the two digits and a number of pulses equal to the tens-complement of said difference to the stage storing the greater of the two digits. If it is only required to transfer the contents of the visual register to a selected one of the store registers 38, 39, then a gate 155 may cut off application of pulses to the respective stages of the visual register as soon as the corresponding carry signal CO1 has been produced. The calculator and its operation is described more fully in the abridgment of Specification 1,172,842.