Patent GB-676416-A (GB)
Title: Improvements in calculating machines
IPC: G06F7/46
Filed: 1948-07-15
Abstract: 676,416. Electric analogue calculating systems. DELFIN, L. July 15, 1948, No. 18989/48. Class 37. [Also in Group XIX] In a calculating machine, the digits of the factors involved are represented by selected proportional currents and the result is indicated and/or recorded by mechanism responsive to the selected currents, preferably by comparing the selected currents with determined currents derived from the same source so that the effect of voltage fluctuation is obviated. Multiplying apparatus.-The machine shown is primarily for multiplying and includes multiplier and multiplicand keys 2 and 3 for selecting voltages proportional to the digits of partial products of single digits, and applying proportional currents through equal resistances to the relevant orders of an accumulator. The electrical connections are shown passing from right to left across Figs. 3, 6 and 7 and with Figs. 8 and 9 above Figs. 6 and 7 respectively. The multiplier key bank is shown in Figs. 3 and 6, the " 3 " to " 8 " keys, however, being omitted, the multiplicand keys in Fig. 7 and the accumulator C and totalizer A in Figs. 8 and 9. A transformer 33 (Fig. 3) is tapped to supply digital voltages 1E-9E which are applied to a system of nine conductors 38 connected through switches 44 with systems of input conductors 41 for the three orders of multiplier keys. Contacts 46 associated with each key are connected to these conductors according to the digits of the nine partial products associated with the key, the contacts when closed by depression of the key applying these digital voltages to conductor systems 47. These conductors pass to the multiplicand bank 3 where they are redistributed between the nine multiplicand digits so that contacts 60, closed by depression of a multiplicand key, select the appropriate partial product voltages and apply them through systems of conductors 61 to the appropriate orders C 1 , C 10  &c. of the accumulator. Resistances 83 of equal value are inserted in the conductors 61 so that currents proportional to the digits of the partial products are applied to the accumulator sections. The digital voltage conductors 38 are continued into the accumulator, where they are used for conrolling transfer between orders and operation of the totalizer. The operated multiplier keys also close circuits, from connections 40 with the conductors 38, to three conductors 48 so that, by closure of a switch 43, the multiplier can be entered in the three highest orders of the accumulator and printed during an initial " factor " cycle. To print the multiplicand, contacts 42 are closed and 49 opened during the initial cycle, this, in effect, entering the multiplicand multiplied by " 1." Accumulator mechanism.-The construction of an accumulator section is shown in Figs. 31, 32, 33 and 35, there being eight sections axially aligned in two groups of four on either side of a set of printing racks 9 (Fig. 1). In each section there is a pair of contact arms 75 and 79 (see also Figs. 8 and 9) rotatable about a shaft 204 to wipe over contacts 38D and 38A connected to the digital voltage conductors 38. The contact arms are each fast with a gear sector 218 and are spring biased to rotate counterclockwise, their movement, however, being normally checked by a pawl 234 for arm 75; arm 79 is connected with a corresponding printing rack which has a pawl normally holding it. Both arms are connected by their sectors 218 and pinions 214 with an escapement wheel 213. Pawls 212 controlling the escapement wheels are rocked by the armature 209 of an electromagnet having a number of windings 64A separately energized by the several digital currents from the conductors 61A, and three reverse windings 78. The armature 209 has a winding 210 constantly energized from a separate tapping 36 of the transformer 33. The action is such that, when the effective total current in the several magnet windings is positive, the pawls 212 are rocked counterclockwise (Fig. 31) against springs 216 and the arms step forwardly over their contacts but, when the total current is or becomes zero or negative, the pawls 212 lock the arms against movement. The action of the accumulator is in two phases. In the first, carry between orders is effected ; contact arms 79 are locked whilst arms 75 are released and a switch 70 is closed to apply a current of 9 units from the system 38 and through resistances 83 and connections 66 to a reverse winding 78 of each magnet so in effect, temporarily neutralizing all but the carry digit currents from the magnets. In those orders where a positive current remains and from which a carry is to be made, the contact arm 75 steps over its contacts 38D until the positive current is outbalanced by a reverse current of 10 units/step applied by the arm and through a resistance 85 of value one-tenth that of the resistances 83, to a reverse winding 78. At the same time the arm 75 applies the appropriate carry current through a resistance 83 to the input system 61A of the next higher order. In effect, therefore, the switch arm 75 moves to a position where it subtracts the carry from its order and applies it to the next. In the second phase the arms 75 are locked in their carry positions, the type racks are released so that the contact arms 79 are free to move and the contacts 70 are reopened to remove the reverse 9 units currents. In an order where a digit is to be recorded the magnet now carries a proportionate positive current and the arm 79 steps over its contacts 38A, so applying an increasing current to a reverse winding 78. When the currents balance, the contact arm becomes stationary at a position corresponding to the digit to be recorded, the type bar moving with the arm. All of the resistances 83 plus the relevant magnet winding are equal. Carbon resistances are used, to provide temperature compensation in conjunction with the copper windings of the magnets, and part may be of the adjustable compression type. The magnet windings may, alternatively, be wound with wire of negligible resistance and their number reduced to two, one for all positive currents and another for all negative currents. Totalizing mechanism.-Each section of the totalizer comprises a series of switches constructed as contact fingers 80 (Figs. 8, 9, 32 and 33) mounted in a block 260 secured to the stationary shaft 204 and selectively rockable into engagement with contacts 38B connected to the digital voltage system 38. A spring 257 biases the fingers into their two end positions. To add the values registered by the accumulator contact arms 79 to a value already registered in the totalizer, switches 82 are closed. This applies to a winding 64A in each order of the accumulator an additional current representing the totalizer digit, the contact arms 79 then moving-on to register the digits of the new total, as when recording the product, carrying with them the type racks 9 to print the new total. Pawls now lock the type racks and arms 79 for the totalizer contact fingers 80 to be set to their new positions. This is done by reciprocating the shaft 204 axially and switching-off the transformer 33. In the downward movement (Fig. 32) of the shaft, the fingers 80 abut a fixed plate 201 to cancel existing settings whilst, in the upward movement, a pin 252 projecting from. each arm 79 selects the appropriate finger 80 and rocks it into engagement with its contact 38A to register the new digit. Bails 221 finally restore the switch arms 75 and 79 to normal.