Patent GB-742181-A (GB)
Title: Improvements in keying mechanism for cryptographic devices
IPC: G09C1/08
Filed: 1952-11-11
Abstract: 742,181. Ciphering. HAGELIN, B. C. W. Nov. 11, 1952, No. 28342/52. Class 146(2) A keying mechanism for cryptographic devices comprises a rotatable drum or the like with a rim of members 11 serving as teeth adjustable into operative or inoperative positions, and a set of key wheels 17-21 rotatable. step by step for setting the members 11, the adjustable members on the 'drum effecting a step by step keying of the key wheels. The drum mounted on shaft 7 for rotation, e.g. by a crank (not shown), has end walls 9, 10 with radial slots for guiding the slide bars 11 which slide longitudially. Each bar is provided with one short keying tooth 15 and one or more shifting teeth 14 the teeth being differently positioned on the different bars. The pin wheels 17-21 carry axially shiftable pins 22, each of which is adjustable to active or inactive position, and have peripheral teeth 28-32. A member 33 carries brackets 34-38 on which pinions 39-43 are mounted to co-operate with teeth 15 and teeth 28-32, and a shaft 49 on which operating levers 50-54 are rotatably mounted. The ends of shaft 49 pass through vertical openings in arms 55. 56 which carry a control bar 57 and may be rotated about shaft 49 or moved vertically, the latter movement being brought about by levers 58, 59 which are pivoted to arms 55, 56 at 64, 65, urged in a clockwise direction by springs 70, 71, and controlled by fingers 68, 69 engaging cams 72. 73. Arms 55, 56 are swung by springs 78, 79 under the control of cams 74. 75 which are engaged by fingers 76, 77. Cams 72, 73, and.74, 75 co-operate to set control bar 57 in one of four positions, namely upper right (i.e. towards pin wheels 17-21), lower right, upper left (i.e. towards the drum), and lower left. Levers 50-54 are swung towards the pin wheels by springs 80, such movement being limited by projections 81-85 should any of the latter engage pins 22 in the active positions. Levers 50-54 have upper and lower holding surfaces 86-90, 91-95, which co-operate with edges 101, 102 of bar 57 and step control surfaces 96-100, on the edges adjacent the drum, for co-operation with the shifting teeth 14. At the beginning of the rotation of the drum, bar 57 is in the upper right position and levers 50-54 are swung by springs 80, the levers which do not. encounter active pins 22 moving further to the right. Bar 57 then moves to the lower right position to secure the levers in their displaced relationship, and then to the lower left position, as in Fig. 7. The levers which had previously abutted active pins 22 are now positioned so that the guide surfaces 96-100 engage teeth 14 and move the slide bars, the remaining levers not affecting the drum. The teeth 15 which are now in active position engage the corresponding wheels 39-43, and turn wheels 17-21. One or more teeth 15 are offset, so that they engage wheels 39-43 when the slide bar is not disolaced, but do not effect the wheel when the slide bar is displaced, to ensure that the keying mechanism operates if all the control levers are in the inactive positions. The different arrangements of teeth 14, 15 on a set of thirty slide, bars is illustrated. To obtain a great number of different keying combinations the teeth 14 may be displaceable, as in Fig. 10, wherein the teeth are pivoted, and each has a raised portion 116 which is engaged in one of two openings 117 in a spring 118. The movements of the pin wheels and the slide bars may be used separately or together to control the ciphering members of a. ciphering machine, e.g. the pins 22, active or inactive of the pin wheels, may act mechanically or electronically on the ciphering means, the slide bars 11 may be provided with teeth for keying electrical or 'mechanical ciphering members. In modified applications, the slide bars may have two or more additional teeth for keying two or more ciphering members at the same time, and the slide bars may be divided into two groups and the keying operation completed in one half revolution of the drum.