Patent GB-702934-A (GB)
Title: Means for facilitating detection of errors in symbol groups
IPC: G06Q40/00
Filed: 1951-05-28
Abstract: 702,934. Calculating-apparatus. REUMERMAN, T., and HELMIG, W. H. T. May 28, 1951 [Feb. 13, 1951], No. 12438/51. Class 106 (1) A means for determining for a symbol group composed from a given series of n symbols numbered in a predetermined order, a corresponding check symbol which indicates the remainder R N (G) obtained by dividing by a given number N a number G= <SP>#a</SP> i <SP>k</SP> i  as defined in Specification 693,250, comprises at least one toothed body for each position i in a symbol group, having teeth each of a different active length, and adapted to be adjusted, by the insertion of a symbol having the number <SP>a</SP> i , to a position in which the number of operative teeth corresponds to <SP>R</SP> N  (<SP>+ka</SP> -ii ), and a carriage including at least one rotatable shaft carrying at least one toothed wheel, such that when the carriage is displaced, after a symbol group has been inserted, the operative teeth of the toothed bodies are successively engaged by the toothed wheel(s) thereby displacing a check symbol indicator coupled to the shaft(s) over t steps such that <SP>R</SP> n <SP>(t)</SP>=<SP>R</SP> n (#<SP>K</SP> i <SP>a</SP> i ). In the device shown, the series of symbols are the digits 0-9, numbered accordingly, N=13, and <SP>K</SP> i =<SP>R</SP> n ( 10 <SP>i-1</SP>) so that K 1 =1, K 2 =10 and so on (six distinct values). The toothed bodies comprise two rotary cylinders 18, 19 for each digit position which are adjusted through toothed gearing operated by a shaft 9 associated with a column of keys 2-5. Each key includes a hollow portion 7, Fig. 3, inside which is a toothed rack 6 which actuates a toothed wheel 8 on the shaft. The rack may be on either side of the shaft so as to rotate it in either direction to bring one or other of the cylinders 18, 19 into operative position, and the number of rack teeth is <SP>R</SP> n (<SP>+ka</SP> -ii ) corresponding to the number of cylinder teeth to be made operative. The carriage comprises an indicator 23, Fig. 2, rotated by differential gearing 24 from shafts 21, 22, supported by levers 26, 27, and carrying toothed wheels 20 one for each pair of cylinders. When the required number has been entered on the keyboard, the carriage is moved upwards from its normal lower position by a manuallyoperated member 35, Fig. 1, through shaft 34 and link-work 33, 31 which locks the carriage in its uppermost position shown, the check symbol being indicated through a window 25. During the carriage return, the indicator is zeroized and, subsequently, spring-controlled detents 42 depending from a beam 40 carried by links 31 engage projections 44 on leaf-spring-supported locking strips 37 to release the depressed keys and return the cylinders 18, 19 to the normal zero position. The check symbols on the indicator 23 may be formed as type adapted to be pressed against a printing roller in the upper position of the carriage, and the number or other symbol group may be printed with the check symbol by type actuated by the keys. In a modification, the toothed bodies are strips slidable in the direction of the teeth and differentially stopped by cam discs which may be coupled to numeral wheels adapted to be set by a full or singlebank keyboard, or by extensions on the keys themselves.