Patent GB-756022-A (GB)
Title: Improvements in or relating to electronic computing apparatus
Inventor: FORMBY JOHN ALBERT
IPC: G06F7/498
Filed: 1952-11-10
Abstract: 756,022. Digital electric calculating apparatus. FORMBY & CO., Ltd., J'. Feb. 5, 1954 [Nov. 10, 1952], No. 26482/51. Class 106 (1). Electronic computing apparatus comprises a plurality of polarizable generators each adapted to emit distinctive trains of signals, and selectable in accordance with a numerical value or values represented by a primary signal or signals. A magnetic track which may be on the periphery of a disc 25, Fig. 2, has digital representations recorded upon it by a magnet 28. The digits may be represented by patterns of magnetization having distinct frequencies and substantially constant amplitudes, a discriminating unit in this case comprising nine frequencysensitive networks 33 each tuned to resonate at the frequency of a particular digit. Each network is connected to the control grid of an associated thyratron 15 and the suppressor grids of these thyratrons are grouped together and brought to a priming potential at an appropriate time in the cycle of the machine. During this time the signal built up by the resonating network 33 causes its associated thyratron to fire. The consequent fall in potential at the anode is communicated through a brush 5 to a metal wheel or bush 2 mounted on an insulating sleeve 3 fixed to a shaft 4. Electrically connected to and turning with the bush 2 is a wheel 1 formed with groups of teeth which pass close by a vane 7 mounted in a plastic support 8, and thereby fluctuating signals are induced in the vane and applied to the control grid of a gating valve 21. The valve passes these signals when the potential on its suppressor grid is brought to a suitable level, and they are applied to a cold-cathode trigger tube 36 forming the input to a multi-cathode counter 44. Any desired numbers of teeth may be formed on the electrostatic generator wheels 1 which can, therefore, provide addition, multiplication or other tables. In Fig. 4 nine groups of generators 1 form a table of partial products for multiplying a multiplicand digit registered in a multicathode tube 61 by a multiplier digit registered in a similar tube 63. The two co-ordinate signals select, via thyratrons 15 and pentodes 21, a single generator wheel 1 having a plurality of groups of teeth representing the units and tens digits, respectively, of the required partial product. The accumulator for the partial products comprises a plurality of multi-cathode counting tubes and the sequence of steps in the process of multiplication is controlled by a commutator consisting of a rotating arm passing over a series of segments mounted in the insulating rim of a wheel. Provision is made for rounding off to any desired number of figures. The input of data may be from a magnetic tape driven by sprocket wheels (Fig. 10, not shown) and the result of a computation may be recorded on the same tape. Adjustable magnetic recording and reading heads enable the resetting of the machine to perform various problems, for example: given x and y to compute x<SP>2</SP>, xy and y<SP>2</SP>. Specification 740,156 is referred to in Provisional Specification.