Patent GB-479854-A (GB)
Title: Improvements in coding and decoding apparatus
IPC: G09C1/12
Filed: 1936-08-11
Abstract: 479,854. Ciphering - apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Aug. 11, 1936, No. 22131. Convention date, Sept. 5, 1935. [Class 146 (ii)] Ciphering and deciphering apparatus comprises a primary typewriter controlling the operation of a secondary typewriter through a single ciphermg-drum also under the control of the primary typewriter, the drum being moved irregularly and arbitrarily by electric means preferably controlled by the primary typewriter. Depression of a key in the primary typewriter T1 causes the actuation of a typelever in the secondary typewriter T2 through contacts 11. 12 and a drum 13 similar to that described in Specification 452,528 ; also contacts 25 are actuated wherebv an electromagnet R1 is energized and rotates a shaft 21s, the breaking of contacts 53 ensuring that the shaft is only fed forward one step. The shaft carries three brushes 21a, 21b, 21c adapted to move over corresponding arcuate series of contacts. Certain of the contacts co-operating with the brush 21c are connected to a brush 24d on a shaft 24s rotatable to move brushes 24a ... e over corresponding series of contacts. When the brush 21c engages a live contact, a battery 30 is connected through the brush, conductor 27, brush 24d, conductor 28 or 29 to magnet R2 or R3 and rotates the shaft 22s or 23s respectively ; relays RL2 and RL3 are also energized and break the associated contacts to limit the rotation of the shafts to one step. When either of the brushes 22c, 23c engages a live contact, the battery 30 is connected to the contacts associated with the brush 24c and thence to a relay RL5 and magnet R5, thus causing the contacts 12 to be moved forward one step to change the cipher, and a brush 35 to be rotated over a series of contacts,36. At the end of a complete rotation of the shafts 22s, 23s, brushes 22c; 23c engage contacts which connect the battery 30 through conductor 40 or 42 respectively to contacts associated with the brush 24e, so causing energization of magnet R4 to cause rotation of the shaft 24s, and of relay RL4 to limit rotation to one step. When it is desired to reset the machine in zero position, a resetting key 45 is operated to permit a battery 46 to energize a magnet 47 to close contacts 48, 49 and open contacts 67. As long as the contacts 67 are open, the battery 30 cannot be connected to the magnets R2, R3. The closing of contacts 48 establishes a holding- circuit for the magnet 47 from the battery 50 through the contacts associated with any of the brushes 21b ... 24b which are not in normal position. The closed contacts 49 connect the battery 46 through conductor 52, brush 21a and its associated contacts to magnet R1 which rotates the shaft 21s step-by-step until the shaft reaches its normal position, when the battery is connected through conductor 52, brush 21a, its last associated contact, brush 22a, and its associated contact to magnet R2 to cause rotation of the shaft 22s. Shafts 22s, 23s, 24s are thus successively returned to normal position, finally disconnecting batteries 46, 50 to permit contacts 48, 49, 67 to return to normal positions. Actuation of the resetting key 45 also connects battery 46 to magnet 55 whereby contacts 56, 57 are closed and contacts 66 opened. Contacts 66 in the circuit of battery 30 prevent energization of magnets R2, R3. Closed contacts 56 establish a holding-circuit for magnet 55 from a battery 58, contacts 59 which are closed except when the brush 35 is in the home position shown, and conductor 60. Closed contacts 57 connect battery 46 to magnet R5 to cause movement of contacts 12 and brush 35 until they have returned to normal position when magnet 65 is connected in the circuit of battery 58, causing the breaking of contacts 59, de-energization of magnet 55, breaking of contacts 56, 57, and engagement of contacts 66.