Patent GB-302237-A (GB)
Title: Improvements in or relating to calculating machines
IPC: G06F7/44
Filed: 1928-12-11
Abstract: 302,237. British Tabulating Machine Co., Ltd., (Assignees of Bryce, J. W.). Dec. 12, 1927, [Convention date]. Adding, subtracting, multiplying, and dividing apparatus.-The terms of a computation to be performed are entered in the apparatus so as to set up, by selection, combinations (for example, energized circuits) representative of the result. The representation may be according to a code and by the operation of a hand lever may be translated into printed digits. Figs. 1 and 1<A> show diagrammatically two sections of the apparatus for deriving the units and tens digits respectively of the result of a simple addition. The left-hand keys 20 for entering one value extend through both sections and carry contracts 37 to close in each section a set of four lines 35 leading to groups of four contacts 32. The other value is entered by means of keys 23 the extensions of which are furnished with lugs as shown in Fig. 8 to cooperate with bails 31 adapted to close the contacts 32 and thus selectively render the circuits alive. The lugs are arranged on each of the four sides of the key stem so that by rotation of the stem a differently arranged lug or combination of lugs may be presented to the bails to give a result in accordance with any one of the four rules. This rotation may be effected by sliding a rack 26, engaging pinions 25 on the key stems, to one of four positions corresponding respectively with addition, multiplication, subtraction and division. In the case of the last-named operation the quotient is given by one section of the apparatus and the remainder by the other section. In subtraction involving a negative difference this is denoted by the minus sign, the lugs being disposed on the keys to close the circuits in a combination representing this sign. The code used is shown in Fig. 6 and enables all the digits to be represented by one or two circuit closures and the minus sign by three such closures. Assuming the apparatus to be set for addition and the 6 and 3 keys to be operated, it will be seen from Fig. 1 that the two upper contacts in the 6 group will be closed, thus representing the digit 9. In the "tens" section shown in Fig. 1<A> however the top and bottom contacts in the 6 group will be closed and this is the combination for nought. Corresponding with the groups of contacts are electromagnets A B C D and A<1> B<1> C<1> D<1> controling contacts 68 - - 71 and 72 - - 75 arranged in separate circuits 54, 55. With any of the con. tacts 32 closed, relays 80, 80<a> are energized to throw in the circuits from the batteries 90, 91. To print the result a lever 43, Fig. 9, may be depressed to rotate type sectors 49 adapted to be stopped differentially by pawls 50, 51 controlled by electromagnets 52, 53 in these latter circuits. Carried by the sectors are commutators 56, 57 the contacts on which ere so arranged that the circuits are completed and consequently the sectors stopped when the contacts arrive under the brushes 58 - - 62 and 64 - - 67 connected with the opened contacts controlled bv the electromagnets A B C D and A<1> B<1> C<1> D<1>. Thus according to which of these electromagnets are energized, singly or in combination, so the digits corresponding thereto are stopped at the printing line where they may be impressed by the hammer 42 cocked and tripped by the movement of the hand-lever 43.