Patent GB-881235-A (GB)
Title: An input device for electronic calculating machines
IPC: G06F3/023
Filed: 1958-07-02
Abstract: 881,235. Digital electric calculating-apparatus. OLYMPIA WERKE A.G. July 2, 1958 [Aug. 22, 1957], No. 21185/58. Class 106 (1). In an input device for an electronic calculating machine, decimal digits entered through a keyboard are passed in binary coded form to a temporary matrix store whose columns are successively selected by a stepping switch. As shown, the row lines I-IV (corresponding to 8, 4, 2, 1 respectively) of the matrix, Fig. 2, are selectively marked through key-controlled contacts 0-9, Fig. 1, in accordance with the value, in excess three code, of an entered digit. Each time a digit is entered, the contacts also break the energizing circuit for relay N thus causing contacts n 1  to close and operate stepping magnet WM which steps on a selector switch having wipers S 1 -S 7 . The circuit of Fig. 2 is arranged to deal with a number having 3 digits to the left and 4 digits to the right of a decimal point. Wiper S 1  marks the matrix column lines 10- 17 in turn through contacts wm, the lines being released by opening contacts a 1 -h 1  of relays A-H which are energized through wiper S 2  half a step ahead of S 1 . The relay hold contacts a 2 -h 2 , when operated, apply positive potential to wiper contacts 20-27. The first 3 digits are entered in columns 12-14, relays C-E being energized; wiper S 5  has then been stepped to a position in which it receives a positive potential (from contacts c 2 ) which energizes relay O. Contacts o 1  break the stepping magnet circuit and light decimal point indicator lamp 65; also, the keyboard may be locked (by means not described in detail). The decimal point key 61 should then be actuated to energize relay P which is held through contacts p 1 , contacts p 2  then being switched over to release relay O and allow digit entry to be resumed. Contacts operated by key 61 also cause relay B to be energized through wiper S 3  and column counter trigger 30 to be primed through wiper S 4 . The following 4 digits are entered in columns 15- 17 and 10, wiper S 2  energizing relays F-H and A. Since relay B also has been energized, wiper S 6  then receives a positive potential (from contacts b 2 ) and relay O is again energized. The circuit of magnet WM is again broken and " end of writing " lamp 66 is lit through switch contacts p 3 . The " calculate " key 68 is then operated which releases relay P and energizes relay I. If fewer than 4 digits had been entered after the decimal point, contacts i 1 , i 2  and i 3  cause zero to be written in the remaining matrix columns. Contacts i 4  initiate operation of a circuit including relays L and K which releases all relays A-H and controls the stepping of row and column ring counters 64 and 30-32 respectively which effect the reading out of the value stored in the matrix e.g. to an arithmetic unit or a magnetic drum. In a modification (Fig. 3, not shown), the number of places after the decimal point may be preselected by setting a switch which controls the relative positioning of the wipers of two selector switches which are subsequently stepped in unison.