Patent GB-972570-A (GB)
Title: Improvements in or relating to calculating machines
Inventor: LLOYD JOHN GEORGE
IPC: H03K17/98
Filed: 1962-07-31
Abstract: 972, 570. Calculating machine input means. BELL PUNCH CO. Ltd. July 26, 1963 [July 31, 1962], No. 29312/62. Heading G4A. A calculating machine includes a keyboard for controlling the entry of numbers into a register, said keyboard including at least one bank of coldcathode trigger tubes each tube associated with the entry of a predetermined digit and each arranged to be rendered conductive by the proximity of an earthed object. In the embodiments shown in the drawings, the earthed object is the operator's finger and is placed over one of a number of metal discs K1. . K9 each connected to the/or a trigger electrode of a corresponding cold-cathode tube. A transparent insulating plate is present between the finger and the metal discs. In modifications, however, the earthed object may be moved near to a conductive coating on the tube envelope itself to render the tube conductive, and may be moved by depression of a movable key (optionally provided with mechanical latching). Fig, 1 shows arrangements for one bank 1K of a fourteen-bank "keyboard". Cold-cathode trigger tubes V1. . V9 are connected in parallel between the positive and negative terminals 11, 12 of a D.C. supply via lines G, F, an A.C. source 13 being connected between the negative terminal 12 and earth. A cyclicallyoperating pulse generator PG supplies, during each cycle, a pulse at terminal PO which goes to a timing device T, followed by one pulse at terminal 1, two at terminal 2 &c. up to nine pulses at terminal 9. Timing device T has sixteen terminals, one of which is selected at a time. Terminal O is connected to line F, terminals 1.. 14 are connected to AND gates IGA &c., one for each bank of "keys", and terminal 15 when selected stops pulse generator PG. If one of tube V1. . V9 is rendered conductive, a corresponding glow lamp N1.. N8 or N9 illuminates a cut-out portion in the metal disc K1 K8 or K9 and the alteration of potential on line F allows timing device T to be stepped by the PO pulses from generator PG. When the bank containing the conductive tube is selected by timing device T, the pulse generator PG passes a number of pulses characteristic of the tube through the tube and via line G and the gate (1GA or &c.) to a counting device (e.g. 1R), associated with the bank, in the machine register. When the timing device T reaches position 15, the pulse generator PG stops until the operator removes his finger when the conducting tube ceases to conduct and the timing device T steps from position 15 to position O, thus allowing the pulse generator PG to continue operation. In a modification the conducting tube may be kept so until the end of a calculation or until a special key is pressed, by having an extra resistance in series with the positive terminal 11 and shortable (e.g. by a relay contact). Fig. 2 (not shown) shows a futher modification in which the pulses are passed to the line G, not through the conducting tube but through an AND gate controlled by the tube, (useful when fast rise and fall times of pulses are to be preserved). Fig. 3 shows another embodiment like a ring counter for supplying a selected number of pulses at a terminal PC for read-in into a counter or register, and including a ring consisting of trigger tubes T1.. T9 controlled by "keys" K1 . K9 and another trigger tube TO. A cyclically-operating pulse generator PG supplies, in each cycle, one pulse P O followed by ten pulses at terminal Z followed by one pulse P11. Initially tube TO is conducting but when the operator makes one of the tubes T1.. T9 conduct by operating one of the "keys" K1.. K9, tube TO ceases to conduct thereby (a) closing an A ND-gate (W12, W13, R14) to remove a biasing potential from a line A so that the operator's finger can have no further effect, and (b) enabling the next PO pulse to switch a bi-stable device B1. Device B1 now opens another AND gate (W10, W11, R50) to allow pulses from terminal Z to pass to line L, each to shift the discharge in the ring along by one tube. The first of the latter pulses also switches a second bi-stable device B2. When the discharge in the ring reaches tube TO (i.e. Via T9) device B1 is switched back thereby closing AND gate W10,W11,R50 thus preventing further pulses reaching the ring, and opening A ND gate W14, W15, W16, R15 thus allowing the remaining pulses from terminal Z to pass to output PC. The pulse P11 now switches back device B2 thus opening A ND gate W12, W13, R14 and closing A ND gate W 14, W 15, W 16, R15. A capacitor C12 was charged via device B2 during the foregoing and now discharges (in about 1 second). When it has discharged the biasing potential is reapplied to line A and the operator's finger, if still on the "key" K1.. K8 or K9 will cause read-out (at P C) of the same number of pulses again. An arrangement as in Fig. 3 may be provided for each of the banks of a "keyboard". The above input arrangements may be used in conjunction with a calculating machine of the type disclosed in Specification 925,161. Specifications 732,018, 868,758 and 938,106 also are referred to.