Patent GB-152625-A (GB)
Title: Improvements in or relating to the production of cipher documents especially adaptedfor telegraphic despatch
IPC: G09C3/00
Filed: 1920-03-12
Abstract: 152,625. Aktiebolaget Cryptograph. Oct. 10, 1919, [Convention date]. Electric machines for coding and de-coding: keyboard operators. - The production of cipher documents adapted for telegraphic despatch in the form of printed type characters or perforated tape &c. is effected by displacing two symmetrically arranged arbitrarily selected series of signs relatively to each other according to a key series also arbitrarily selected, but each time a certain text letter-the influence letter--occurs the series of signs remaining still or being displaced a distance selected arbitrarily regardless of the key series, the standstill or the displacement affecting the ciphering of the letter following the influence letter. Shown diagrammatically in Fig. 1, T represents the ciphering-keyboard. T1 an ordinary typewriter, and T2 the typewriter or other machine for producing the ciphered message. A rod a having a metal pin s is connected with each key T and makes contact with a rhombic conductor r, Fig 1<a>, joined to a source of current S. Metal springs k1, k2 force the pin around the rhomb making the following electrical connexions. On the downward movement the spring is joined to the solenoid S1, which operates the lever b to print the sign on the typewriter T1, selected by the key at T. Simultaneously a circuit is made through the ciphering-members C1, C2 by way of springs k3, k4 and solenoid S2 to print or punch a cipher sign, corresponding to the selected text sign. On the outward movement the spring k8 is joined to the solenoid S3 which operates a device for adjusting disks N1, N2 each having an arbitrary number of projections u which make or miss contact with springs k3, k6, these springs being in circuit with solenoids S4, S5, provided with operating means for adjusting the cipher members C1, C2' To operate the cipher members regardless of the key series, a switch d normally in the break position of an electro-magnet M is closed upon the magnet when the key corresponding to the influence letter has been actuated, the circuit of the solenoids S4, S5 being thereby broken. On this operation the cipher members remain motionless. To impart motion to the cipher members on the actuation of the key of the influence letter, the switch d may be placed in the circuits of the solenoids S4, or S5 the amount of motion given to either cipher member being arbitrarily chosen. For deciphering, the electro-magnet M is associated with the solenoid S2 of the key T2 corresponding with the influence letter so that each time a cipher sign corresponding to the influence letter is touched on the keyboard T the original text letter is produced on the machine T2. Shown constructionally in Figs. 2, 4, 5, and 6, the cipher members are fast on shafts 21, 22 and have end pieces 29, 29a in the form of ratchets. Insulated rings, 25, 25a are mounted upon the cipher members which are also provided with disks of insulating material containing contacts 35, 35a electrically connected by spring pin members 38, 38a, the number of rings and contacts each equalling the number of keys T, the electrical connexions being in complete reverse order on each cipher member. Contacts 66 made on the rings 25, 25a correspond with the springs K3, K4 in Fig. 1. The ratchet teeth 41, 41a on the end pieces 29, 29a are also in number equal to the keys T and are engaged by pawls 42 operated by the armatures of electro-magnets 47 (corresponding with the solenoids S4, S5 in Fig. 1). Excitation of either or both of these electro-magnets is obtained through the electro-magnet 76 (corresponding with the solenoid S3 in Fig. 1). The armature of the electro-magnet 76 has a pawl 55 engaging a ratchet-wheel 51, to which is secured another toothed wheel 52 in gear with other wheels 53, 54. On the wheels 52, 54 respectively are mounted disk members 60, 61 driven by locking-members 62, 63. Lugs 60d are fitted in the disc members in certain numbers, provision for 13 and 11 being shown in Fig. 5. With this arrangement the lugs make or miss contact with members corresponding to the springs k6, k5 in Fig. 1, and' thereby excite or do not excite the electro-magnets 47, which in turn cause the cipher drums either to rotate or to stand still. On depressing the key of the influence letter, the armature 76' of the electro-magnet 18, Fig. 2 (corresponding with the electro-magnet M, Fig. 1), breaks contact at 80 and is latched by the pawl 81, this latch being released and contact restored on the actuation of the key of the next letter. The pitch and gears of the meshing members is such that as long a series of mutation as possible is obtained. Fig. 6 shows toothed gearing for producing a greater movement of one cipher drum 71 than of the other. Arbitrary relation of the key wheels may be obtained by changing the number of the interengaging wheels and contact lugs. More than one influence letter may be used in which case, for deciphering, an electro-magnet 18 must be associated with each solenoid S2 corresponding with the influence letters, in the machine T2.