GB914330A - Improvements in or relating to decimal-point indicators for calculating machines - Google Patents

Abstract

914,330. Calculating-apparatus. PHILIPS ELECTRICAL INDUSTRIES Ltd. April 14, 1959 [April 14, 1958], No. 12624/59. Class 106 (1). A desk-calculating machine is provided with means for indicating the position of the decimal point in the result. The invention is applied to a machine for the four rules having an output register I and an input register II divided into two parts a and b. Multiplication is by repeated addition and division by repeated addition of complements, the means employed not being described in detail. The possible interdigital positions of the decimal point are referenced- 61 ... - 2<SP>1</SP>, - 1<SP>1</SP>, 0<SP>1</SP>, 1<SP>1</SP>. . ., 9<SP>1</SP>, and a decimal point indicator KA, Fig. 8, is connected to the various outputs 21-36 of a ring counter SR. For addition and subtraction, a button C is depressed initially to set the decimal point to the position 0<SP>1</SP>. The registers I, II are zeroized and the first number in the arithmetic operation is set in the register II. An " add " button is then depressed, to close a switch O, Fig. 8, and transfer the number from the register II to the register I. To place a decimal point in point position i<SP>1</SP> (i = 0, ..., 9), a key Ti is depressed thereby supplying i pulses from a pulse generator PG over contacts C<SP>1</SP>i, switch O, and lead 19 to the ring counter SR to move the point i places to the right to the position i<SP>1</SP>. For multiplication the two factors are written in the parts a and b of the register II (see Fig. 4a), the button C is depressed to the set, the decimal point to the position 0<SP>1</SP>, the " multiply " button is depressed to close a switch V and cause the product to appear in the register I, Fig. 4b. Keys T0-T9 relating to the points in the factors are then depressed, the pulse generator PG supplying pulses over the actuated contacts C<SP>11</SP> 0 -C<SP>11</SP> 9 and line 19 to position the point correctly in the product, Fig. 4c. For division, the dividend with its decimal point is entered in the register I, as described for addition. The divisor is then entered in the part a of the register II and the " divide " button depressed to close a switch D and cause the quotient and remainder to appear in the register I. The key T0-T9 relating to the point in the divisor is then depressed, the ring counter SR is then stepped to right, Fig. 8, sufficient to effect the required left shift of the decimal point.