Patent GB-1085070-A (GB)
Title: A system for checking multi-digit numbers
IPC: G06F11/10
Filed: 1965-12-23
Abstract: 1,085,070. Calculating apparatus. WALTHER-BœROMASCHINEN G.m.b.H. Dec. 23, 1965 [Dec. 23, 1964], No. 54691/65. Heading G4B. A system for checking a multi-digit number keyed into a ten numeral key keyboard by reference to a check digit derived from the number by multiplication of each digit by a weighting factor characteristic of the decimal place of the digit and by the. summation or other manipulation of the products obtained, comprises a contact operable by each numeral key, switch means (19, Fig. 2) associated with the key contacts and adapted to operate with reference to the decimal place of each digit keyed into the keyboard, and a data storage device adapted to receive a pulse from the appropriate key contact and the switch means (19) after each digit has been keyed to provide a first signal to indicate that the number has been correctly keyed or a second signal indicating an error. The multiplication of the respective digits and weight factors is performed in a diode matrix 3, Fig. 9, in which the results of all multiplications reduced by a predetermined modulus (eleven) are represented by cross-over points. The switch means 19 comprises a wiper quadrant carrying a printed circuit contacted by springs (not shown) so as to continuously establish two circuits, Fig. 9. The wiper quadrant is mounted on a shaft 20 and is deflected by the stepping of the pin carriage 17 via linkage 18, 18<SP>1</SP>, 18<SP>11</SP>. The function of the wiper quadrant is to select different cross-over points in the matrix as consecutive digits are keyed, the matrix causing the keyed digit to be multiplied with the appropriate weighting factor. The pulse for activating the matrix is supplied by a microswitch 23 which is actuated by switching rod 24 each time the pin carriage steps. While the storage device consists of an electronic counter, and while this contains a remainder the machine is locked by magnet (25) (Figs. 6 and 7, not shown). A lamp may replace or be provided in addition to the magnet. Matrix-The matrix 3, Fig. 9, is based on a modulus of eleven. Weighting figures are allocated to each of ten positions of the pin carriage with key digits 0-9 as co-ordinates. The Specification explains how the 100 results can be reduced to the twenty-five as shown. At these points semi-conductor diodes 22 are located and connected to an electronic counter via key contacts and taps (q, r, s, t, u) in such a manner that the counter will add or subtract the value associated with the diodes according to the sense of the pulse through the connections. Keyboard.-The ten-key keyboard comprises a plate carrying a printed circuit, a guide plate and an insulating plate. The shafts of the keys pass through holes in these plates and are offset so that their bottom ends (16) are in parallel alignment. The holes in the plates allow for the passage of a contact ring which is urged by a spring against a contact of the printed circuit. Depression of a key pushes the ring clear of the printed circuit. Decimal point indication.-A decimal pointer 17<SP>11</SP>, Fig. 2, is connected to a pin carriage 17 and indicates the position of the carriage in a window bearing a scale 17<SP>111</SP>.