GB931863A - Improvements in or relating to calculators - Google Patents

Abstract

931,863. Mechanical calculating-apparatus. G. BADALAMENTI. July 14, 1959 [July 14, 1958], No. 24218/59. Class 106 (1). A mechanical calculating device for resolving given numbers into their prime factors comprises a rigid strip A bearing groups of inclined lines corresponding to prime numbers, and perpendicular scales A<SP>1</SP>, A<SP>11</SP>, and a cursor B which slides along the strip A and itself carries a slide C bearing a reference point at the centre, movable in a direction transverse to A. As shown, the graduation of the scale A<SP>1</SP> represents the odd numbers 1-99 only, and the graduation of the scale A<SP>11</SP> represents the hundreds (0, 100, 200, . . .). A network of lines is drawn parallel to these scales and any intersection may be represented by an ordered pair of numbers, e.g. (300, 41) which is taken to represent the single number 300+41, i.e. 341. Multiples of prime numbers are plotted upon the line matrix, for example if the prime 17 were to be plotted 1 X 17=17 would be at the point (0, 17), 2 x 17= 34 would be at (0, 34), . . ., 21 x 17=357 would be at (300, 57). A group of lines is drawn through points representing multiples of 17 which lie upon different " hundred lines." These lines have a characteristic slope and a corresponding line for the prime 17 is marked on the annular cursor. These lines are drawn for all primes up to a chosen limit. Multiples of primes of a higher order may simply be marked by a dot or circle on the matrix. To operate the reference point of the slide C is brought above the point representing the number whose prime factors are required. Any lines on the cursor which coincide with lines on the strip indicate the particular prime factors present.