Patent GB-1130901-A (GB)
Title: Keyboard control for computing machine
Inventor: DELI GEORGE CHARLES
IPC: G06F3/023
Filed: 1964-10-06
Abstract: 1,130,901. Keyboard controlled pulse-selectiori. MULLARD Ltd. 4 Jan., 1966 [6 Oct., 1964], No. 40711/64. Heading G4A. [Also in Division H3] In a keyboard control apparatus for selecting a desired number of pulses from a pulse source to control the eounting in an electronic store of a computing machine having a radix of n comprising a keyboard having digit keys one for each digit up to (n - 1), a pulse-divider operable to divide a train of n-timing pulses into separate pulses and responsive to actuation of a digit key to select a number of pulses corresponding to the actuated key, and a gate operable by the selected timing pulses to control the application to the electronic store of higher-frequency counting pulses from a counting-pulse source, the pulse-divider has an input terminal and a series of intermediate output terminals and is operable upon receipt of consecutive pulses of a train of timing-pulses to connect consecutive pulses in the train to consecutive intermediate output terminals in sequence, a group of diodes is connected one to each intermediate output terminal of the pulse-divider and a group of digit-key contacts is connected one to each of said intermediate output terminals, and the elements of one of said groups are connected between each pair of consecutive intermediate output terminals and the elements of the other group are connected between respective inter-. mediate output terminals and a common output line, whereby when one digit key is actuated there appear at the common output pulses corresponding in number to the actuated digit key. In an arrangement for selecting a desired number of consecutive pulses from a train of pulses applied for example to a cold cathode stepping tube V k , nine manually operable keys DK1-DK9 are provided together with nine diodes D31-D39, the arrangement being such that on depressing, for example, key DK4 the direct path to the negative line (NEG) is broken for keys DK1-DK4 and the circuits for cathodes K1-K4 are therefore completed through diodes D31-D34 in parallel and through resistor R40 whereby four pulses appear at terminal PS1 after amplification at A2. Resistance R40 may be omitted if A2 is a currentamplifier. At the end of one complete cycle of the tube V k  a control pulse may be generated (by means not shown) to indicate that selection of the required number of pulses has been effected. Timing pulses for use elsewhere in a calculator circuit (not shown) may be derived from cathode KO. Alternative circuit arrangements of the diodes and keys are illustrated in Figs. 4 and 7 (not shown), both arrangements involving transposition of the key and diodes with respect to Fig. 3, both using make switches in place of break switches and the Fig. 7 arrangement including a transistor. The invention may be applied to a desk-type key-operated calculator. The selected timing pulses may be used to step pulse counters for additions or to gate higher frequency trains of pulses for use in multiplications. The cold cathode stepping tube may be replaced by a pulse-operated switch of the uniselector type or by a multi-stable ring counter.