Patent GB-324734-A (GB)
Title: Improvements in or relating to the coding and decoding of messages
IPC: G09C3/00
Filed: 1928-11-12
Abstract: 324,734. Budd, J. G. H. Nov. 12, 1928. Type-wheel machines for coding and decoding; letter-spacing mechanism.-A ciphering-machine is provided with keys corresponding to the characters to be used and a printing-device controlled by the keys, and by ciphering-mechanism through two sets of differentially-acting gearing to set the printing-device forward or backward according to the digits of a code number. The keys a, Figs..1 and 3, bearing the type characters, are pivoted on a shaft b and are arranged to depress a bar d carried by arms e, e<1> secured to the shaft b, so that the shaft is rotated different amounts according to the key depressed, the keys being provided with stops a<1> of varying length adapted to engage the baseplate of the machine. The shaft b carries segments g, g<1> connected by a bar g<2> adapted to be raised by the ends ax of the key-levers, the segments engaging gear-wheels h, h<1> on a shaft i which, by means of a train of gearing k, rotates a shaft m carrying a gear-wheel n, Fig. 5, in mesh with a second gear-wheel n<1> on a pin n<2> fixed to a disc x connected to the type-wheel y. An arm o, Figs. 1 and 3, fixed to the shaft b is arranged to rotate a segment r which, through a train of wheels s, rotates a shaft t adapted to be connected by a slidable clutch D to either of the bevel wheels A, B in order to rotate a shaft uforwards or backwards according as the characters of the message printed by the wheel y are in front of or behind the characters of the original message. The shaft u carries a gear-wheel v, Fig. 5, in mesh with a gear-wheel v<1> on a pin v<2> on the disc x, the wheels n', v<1> being also in mesh. The extent of rotation of the shaft t is controlled by a spring finger 13a, Fig. 3, on a crank 13 on the shaft. Spring-pressed stops, numbered 0-8, and a fixed stop 9 are provided on a plate E over which the crank moves, and the stops are arranged to project successively according to the figures of the code number and to stop the rotation of the crank, shafts t, u, wheels v, v<1>, and type-wheel y. A spring p between the arm o and segment r allows the keys to complete their movement after the crank 13 has been stopped. Cams 11, corresponding in number to the number of figures in the code number, are arranged to act in succession, according to the figures of the code number, on arms 21, Fig. 6, pivoted to the plate E and engaging the respective stops. To enable the cams to be adjusted when the code number is changed, they are preferably provided with hexagonal holes and mounted on a correspondingly-shaped shaft 12. The shaft 12 is provided with a ratchet wheel 14 engaged by a spring-pressed pawl 15 actuated by a lever 17, spindle 18, lever, and link from an arm integral with the arm e, the arrangement being such that on depression of a key, the pawl 15 slides backwards over the teeth of the wheel but engages them to rotate the shaft 12 through one step on the return movement of the key under the influence of a spring c. The ciphered or deciphered message is printed by the wheel y on to a strip of paper 22 fed from a reel 23 by wheels 25, 25a, the former of which is serrated and engaged by a pawl on a slide 27 connected by a bell-crank lever 28, Fig. 9, to a slide 29 normally held retracted by a spring 30. An arm 32 on the arm e<1> engages, when a key is depressed, a pin 31c on a plate 31 pivoted on the shaft b and provided with a projection 31a engaging a pin 29a on the slide 29. Forward movement of the slide causes the pawl to slide over the wheel 25, but on the return movement the pawl rotates the wheel to feed the paper. The paper may be fed without actuation of the mechanism by means of a handle 31d on the plate 31. The arm 32 is connected by a pin-and-slot connection to a bar 38, the outer end of which lies in a right-angled rotch 37a in a disc. 37 mounted on a shaft 35 to which is also connected a lever 34 under the influence of a spring 36. Depression of a key results in a certain amount of idle motion of the arm 32 relative to the bar 38, but the bar is finally moved to rotate the disc until it can slip over the edge of the notch when the spring 36 rapidly returns the lever 34 beyond its normal position so that a striker 33 thereon forces the strip of paper into engagement with the letter on the type wheel y which has been set in position by the operation of the key and ciphering-mechanism. The type is inked by a roller 40, or an ink-ribbon may be provided. Instead of driving the, wheels n, v through mechanism actuated by the keys, they can be driven by a motor such as a spring motor or, if a friction clutch is provided, a continuouslyrunning motor, so that the shafts can stop when necessary. The shaft t, Fig. 12, is driven, under the control of the ciphering-mechanism located at X, from a shaft 47 provided with a bevel-wheel 48 coaxial with a bevel-wheel 46 driving a shaft 44 controlling the rotation of the gear train k. The bevel-wheels 46, 48 form, with bevel-wheels 49, 50 carried by a casing 51, a differential gear actuated by worm-gearing 52 from a motordriven shaft 53. When the motor is started, the shaft 47 is rotated through the differential gear, the shaft 44 being held against rotation by a stop 68, Figs. 12 and 13, engaging an apertured wheel 67. The shaft 47 carries the crank 13, and this is stopped by the spring-pressed stop set by the ciphering-mechanism after having rotated the shaft u and set the printing-wheel y the correct distance in advance of or behind its zero position. The keys are pivoted on a shaft 61 and are under the influence of springs 62. Depression of a key results in the withdrawal of the stop 68 from the wheel 67 through the movement of an arm 64 carrying a bar 63 which lies beneath the keys. This permits the shaft 44 to be rotated by the motor to rotate also the gears k and shaft m. The shaft 44 carries a cylinder 55 having a helical slot 56 forming a complete convolution, and the slot is adapted to be engaged, in order to stop the rotation when the wheel y has reached the correct position, by a stop 57 associated with the depressed key. These stops are pivoted on a shaft 58 and are normally held in inoperative position by projections 60 on the keys. They are also connected to the keys by springs 59, so that depression of a key causes the corresponding stop to bear on the surface of the cylinder until it can snap into the slot 56. This releases the corresponding lever 66 which was held by a pin 66a engaging a slot in the stop. The key lever, which was also held by the pin 66a, is thus permitted to be further depressed and to depress the lever 66 pivoted on the shaft 61, and an arm 69 carried by levers 70 also pivoted on the shaft 61. One lever 70 controls the printing-mechanism, through an arm 72, and the feeding of the paper strip, and the other lever 70 controls the step-by-step movement of the cam-shaft 12.