Patent GB-956057-A (GB)
Title: Mechanical and electronic calculator
IPC: G06F7/62
Filed: 1961-11-13
Abstract: 956, 057. Digital electric calculating apparatus. M. L. LEBAR. Nov. 13, 1961 [Nov. 15, 1960], No. 40563/61. Heading G4A. A calculator includes a pulse generator including a first member mechanically-driven at a speed which is an integral multiple of the speed of a second mechanically-driven member. The calculator includes a keyboard C, the generator GI of electric pulses, a two-section counter comprising a forward counting mechanism CC and a backward counting mechanism CD, and an electronic totalizing counter CR. Generator GI contains two coaxial drums T 1 , T 2 , the outer drum T, revolving at a speed 100 times that of drum T 2 . An illuminating bulb L is positioned outside drum T 1 , inside which are positioned, on a carrier S, eighteen photo-cells P which face bulb L and register respectively with eighteen tracks on drums T 1  and T 2 . Track 1, registering with cell PO, is provided with one hundred uniformly spaced perforations, tracks 2 to 5 and 11-14 registering respectively with four cells PM and four cells PD with 10, 20, 40 and 20 perforations respectively, tracks 6 to 9 and 15 to 18 registering respectively with four cells PC and four cells PU with 1, 2, 4 and two perforations, and track 10, registering with cell PCY, with one perforation. Depression of the keys on keyboard C make effective the required photo-cells. Since the operative cycle corresponds to a complete revolution of drum T 2 , the number of pulses fed through the output SI, connected to cells PU, PD, PC and PM, may vary between 1 and 9,999 depending upon which keys of the keyboard are depressed. The output SI is connected to a four-position switch K3. When switch K3 is in position a or m corresponding respectively to the arithmetic operations of addition and multiplication, output SI is connected to the input E1 of counter CC or to the input E3 of counter CR through a switch KZ, and when switch K3 is in either of positions s or d corresponding to subtraction and division, output SI is connected to the input E2 of counter CD. The output SDY, consisting of the clock pulses from cell PO, is connected through switches K5, KZ with input E3 of counter CR, and the output SCY, consisting of one pulse per cycle from cell PCY, is connected through switch K4 with input E2 of counter CD. For multiplication, the system works as follows. The multiplier is entered on the keyboard and, by operating the addition key, fed into the counter CCCD. The multiplicand is then entered on the keyboard and, by pressing the "X" key, switches K1, K4 are closed and switch K3 is placed in position m. Generator GI is started, and in each cycle the number of pulses equal to the multiplicand is fed into counter CR, and at the end of each cycle, output SCY feeds a pulse into input E2 of backward counting counter CD. When counter CC-CD is brought to zero, relay RZ is energized to open switch KZ and the result of the multiplication is registered in counter CR. In the case of division, the dividend is first entered into counter CC -CD and then the divisor is set up on the keyboard and repeatedly subtracted from the dividend while the uniform pulses SDY pass from the generator to the totalizer CR to register the quotient. The apparatus may be used in a weighing machine for indicating the total price of goods weighed. When during its follow-up movement a searching arm G7 reaches the position occupied by the hand Gl of the scales, hand G1 and arm G7 being pivotally mounted on a spindle G2, the mass of a plate G3 on hand G1 disturbs the field between two windings G5, G6 forming part of an oscillator G4 which controls an electric motor M driving the two drums of the pulse generator GI, thereby stopping the oscillations, motor M and the counting of the pulses. Generator GI is adapted to send weight pulses to a first counter C1 through output SDY and price pulses to a second counter C2 through output SI. The number of tracks and perforations thereon may be varied depending on the required use of the calculator and the detecting means may be constituted by magnetic heads associated with magnetic carriers, or the photo-cells may be energized by light passing through transparent drums or discs which have been made opaque in certain sections.