Patent GB-564423-A (GB)
Title: Improvements in or relating to multiplying machines
IPC: G06F7/46
Filed: 1943-03-02
Abstract: 564,423. Calculating apparatus. NATIONAL CASH REGISTER CO., Ltd., and SAXBY, F. R. March 2, 1943, No. 3422. Drawings to Specification. [Class 106 (i)] A multiplying machine, which may, if required, be conditioned to function as an adding machine, comprises means for forming in succession the terms of a convergent series obtained by dividing (ignoring fractions) the multiplier by successive powers of two, an odd values register for receiving the odd values in said convergent series, means operably sub-- sequently to form in succession the terms of a divergent series obtained by multiplying the multiplicand by successive powers of two, and means controlled by the odd value register for entering into the accumulator those terms of the divergent series which correspond to the odd values received. As the sum of the odd values is equivalent to the multiplier when expressed in the binary notation, the process of halving may be omitted and the binary values may be set up directly. In the embodiment described, the machine comprises a group of electrical digital value relays constituting the factor register, a group of self-locking relays forming the odd values register, a group of rotary telephone type switches for finding the terms of the divergent series corresponding to the odd values to be entered into the accumulator, a number of sequence relays for controlling the cycles of operation, and a group of electro.- magnetic operating means comprised in the accumulator and controlled by the rotary switches. In operations involving non-uniform notations such as sterling, a full keyboard is provided for all denominations of the sterling amount and the various pounds denominations or decimal part serve for entering the number by which the amount is to be multiplied. Associated with each key is a relay having a digital value and connected therewith are transfer relays that function during the halving and doubling cycles under control of the sequence relays. When the digit in the lowest denomination of the factor being halved is odd, a relay in the odd values register is locked under control of the rotary distributer switch. The locked relays act as special controls during the subsequent doubling process. The machine operates in two phases; in the first phase, the main key is thrown to connect up to the supply circuit and a start key is momentarily depressed. The multiplier is then entered and an operation key depressed to initiate the halving cycles and to register the odd values in the odd values register. These cycles of operation continue until the factor register is reduced to "00" when the circuits will be ready for the second phase. During the second phase, the multiplicand is entered and the operation key is again depressed to initiate doubling cycles. The distributer switch takes a step for each doubling cycle until a locked odd value relay is found, whereupon a circuit change is effected to transmit the corresponding doubled multiple of the amount to the accumulator. After this entry has been effected the distributer switch and sequence relays continue the doubling cycles until the next locked old value relay is reached and the new multiple is added to that standing on the accumulator and so on until the final product is obtained. The accumulator comprises numeral wheels frictionally mounted on a motor driven shaft and under the control of electromagnetically operated escapements and a rotary finder or result switch with leads associated with the relays of the factor register. The operated relays in the different denominations of the factor register opens the corresponding one of a chain of contacts in the respective denominations of the result switch therebv limiting the number of impulses to the escapements in accordance with the values. A carryover system with relays, contacts and wipers is provided to effect transfer between the accumulator denominations after the result switch has functioned. Zeroizing means are provided to normalise the machine. If, however, it is desired to retain the multiplier in the odd values register for subsequent computations, a special key is depressed prior to the depression of the zeroizing key, in which case the accumulator only will be reset to zero. Addition operation. The machine can be used as an adding machine if provision is made for energizing the 2 relay only of the odd values register and conditioning the machine for the second phase operation. This is effected by depression of an add key. On entry of an amount in the factor register and depression of the operation key, the distributer switch steps on and a control relay is energized to enter the amount in the accumulator, the distributer thereafter performing idle doubling cycles rapidly. Direct entry. By providing keys similar to the add key, the multiplier can be set up directly by controlling the other relays of the odd values register. Specifications 501,538 and 541,909 are referred to.