GB191225345A - Apparatus for Computing Interest and the like. - Google Patents

Abstract

25,345. Simtion, P. Nov. 5. Tabular calculators. -Apparatus for computing the number of days between given dates, and the interest on sums of money for such periods at given rates per cent comprises either a flexible-strip or a disk form of date-computing apparatus together with interest - computing means consisting of flexible strips mounted on pairs of rollers. In the form of apparatus shown in Figs. 1 and 2, a complete calendar is printed on each side of the flexible strip 28 and columns of intervals in reverse order on the strip 29, one side being for a 360-day year and the other for a 365-day year. The numerals on the front of the strip 29 run from 0 to 180 and are repeated twice. By setting one date on the strip 28 against the zero in the centre of the strip 29, the interval between the given date and a preceeding or succeeding date can be determined. The rollers 27 upon which the strip 29 is mounted are provided with squared sleeves 24 capable of sliding laterally without moving the rollers so that the pairs of buttons 25, 26, and 21, 22 of the rollers 27, 23 respectively can be turned independently, or so that the outer roughened surface of the buttons 25, 26 may engage with the corresponding inner surfaces of the buttons 21, 22 and both pairs be turned together. The interest-computing portion of the apparatus comprises a flexible sheet 5 mounted on rollers 1, 2 and having a column of intervals expressed in days along each edge of the sheet: the interest on the sums of money marked along the upper edge of one or more apertures 6 in the casing at the rate shown thereon for the period shown (in this case 90 days) appears in the said apertures. One side of the sheet shows the interest at one rate and the other side in a different rate per cent. In. a second form of apparatus (not shown) the setting of the two dates by means of disks and pointers moves a toothed segment which, in turn, through a train of pinions sets interest-computing tables for the required interval. The number of rollers and bands employed may be varied, and the intervals may be printed transversely on the band, the band 29 in this case resembling the band 5 shown in Fig. 2.