Patent GB-423596-A (GB)
Title: Improvements in or relating to steganographic typewriters
IPC: G09C3/00
Filed: 1933-08-01
Abstract: 423,596. Ciphering - machines. AUVRAIN, F. L. J. D', 102, Rue du Croissant, Brussels. Aug. 1, 1933, No. 21632. Convention date, Aug. 5, 1932. [Class 146 (ii)] [See also Group XVI] In ciphering - type - writers provided with two relatively-adjustable type-wheels for producing clear and ciphered text, the wheels are mounted on a common shaft and each is connected to a corresponding disc, one of which is driven by friction from the other until stopped by one of a series of detents adapted to be actuated by the keys of the keyboard, and both of which are provided with a series of detents adapted to be moved into the path of rotation of each other to stop the rotation of the second disc. The keys 1 are carried by levers 2 each connected to bell-crank levers 3, 4 pivoted on fixed axles 5 and connected by links 6 so as to give a parallel movement, the levers being normally held in neutral position by springs 7 mounted on a rod 8 and engaging pins 9 carried by the links 6. Combs 10, 11 maintain the relative positions of the key-levers. Depression of a key causes the rocking, through a connection 12, of a corresponding detent 13 pivoted on a circular spindle 14 in a slot of a supporting-ring 15. A series of plates 16 is pivoted on a transverse member 17 carried by a spindle 18 beneath the keyboard, the plates being provided with projections which can be placed in the path of movement of the universal bar 19 and raised thereby to lift the corresponding key-lever. The plates 16 are set in operative position by studs 20 on a drum 21 slidably mounted on a square shaft 22. The shaft carries a ratchet-wheel 23 engaged by a pawl 24 on a crank 25 rocked by a link 26, crank 27, and shaft 28. The action of the pawl on the ratchet-wheel is controlled by a shield carried by a lever 75 pivoted on the shaft 22 and adjustable along a toothed quadrant 76. The longitudinal position of the drum relative to the shaft 22 is determined by a projection 77 adapted to engage apertures in a scale member 78. Fixed to the shaft is a graduated disc 73 moving past a pointer 74 for determining the starting-position for the rotation of the drum. Above the key-levers is mounted a frame comprising two sections 29, 30 secured to the ring 15, the frames supporting a shaft 31 on which discs 32, 33 and type-wheels 34, 35 are mounted. The types on the wheels 34, 35 are arranged in inverse order. The shaft carries a gear-wheel 36 in mesh with a second gear-wheel 37 rotated by gearing from a shaft 38 actuated through a friction clutch 39, 40 by a crank handle 41. The disc 32 and the type-wheel 34 are keyed to the shaft 31, while the disc 33 and type-wheel 35, which are connected together, are driven by friction by an endless helical spring 42 mounted in a V-groove formed between two abutting plates 43, 44 secured respectively to the wheel 34 and disc 33. The type are formed directly on the rim of the wheel 35, but the type-wheel 34 is adjustably secured to its hub 45 by means of pins 46 arranged circumferentially; the type-wheel can be raised out of engagement with the hub by means of a lever 47 adjustably mounted in the frame section 30. The type-wheels are each formed with a projection 48, 49, with which stops 50, 51 can be caused to engage by pressure on knobs 52, 53 against the action of springs. The discs 32, 33 each carry a number of L- shaped detents 54, 55 pivoted on circular spindles in slots in the edges of the discs, the number of detents in each disc being equal to the number of key-levers. The detents are normally retained in adjusted position by means of washers, and the detents are movable so that the vertical arms can be brought into or removed from the positions where those of the two discs engage during rotation. The horizontal arms of the detents are engageable by the detents 13 or by a special detent 56 connected to the universal bar 19 for the purpose of setting the vertical arms in engaging position. The horizontal arms are also engageable by the flanges 57, 58 of a ring of I-section, so that the actuation of the ring sets the detents in normal inoperative position. The ring is supported by members 59 attached to a rocker 60 pivoted to the frame section 29 and supported by a lever 61 which is under the control of an arm 62 lying in the path of the crank-handle 41. Visible impressions are obtained on two strips of paper 63 by means of ink ribbons and hammers 65 actuated by a finger 66 on the shaft 28. The shaft 28 is rocked by a crank 67 pivoted to a rod 68 connected to the crankhandle 41. In use, the arm 62 is first rocked to raise the ring carrying the flanges 57, 58 to place the detents 54, 55 in inoperative position. The drum 21 is adjusted to a predetermined circumferential and axial position by means of the disc 73 and pointer 74, and the projection 77 and apertured scale 78. The lever 76 is then adjusted to give the desired feed of the drum at each oscillation of the crank 25. The type-wheels are then set in correct starting- positions by first pressing in the knob 52 and rotating the crank-handle 41 to cause the rotation of the shaft 31. The wheel 35 is rotated by friction of the spring 42 until the projection 48 encounters the stop 50. The knob 53 is then pressed, and the rotation of the handle 41 continued, the spring 42 slipping to allow the wheel 34 to turn until it is stopped by the projection 49 and stop 51. During the stroke of the handle, the drum 21 is rotated and one of the studs thereon engages a plate 16 and moves it into operative position. At the end of its forward stroke, the handle engages the arm 62 and raises the rocker 60 and the flanged ring 57, 58. On the return movement, the handle releases the arm 62 and then engages a pivoted catch 69 on the end of a lever 70 connected to the universal bar by a link 71, the bar being thereby rocked and raising the plate 16 set by the drum. The lifting of the corresponding key-lever causes the depression of a detent 13 and the deflection of the detent 55 opposite thereto. The handle now slips past the catch 69 permitting the bar 19 to fall and to reset the parts carried thereby, the adjusted detents 54, 55 remaining in position in view of the friction of the washers. The knobs 52, 53 are now released. The key corresponding to the first letter of the message is depressed, thus raising the corresponding detent 13 into the path of movement of a projection 72 on the disc 33. The handle is rotated to rotate the shaft 31 and the disc 33 is rotated by the friction of the spring 42 until the projection 72 engages the detent 13. The disc 32 continues to rotate until the detents 54, 55 set in operative position engage. Further rotation of the handle is permitted by the friction clutch 39, 40, this rotation first causing the' actuation of the hammers 65 to obtain an impression of the types stopped opposite the printing-point. Near the end of the forward stroke, the handle rocks the arm 62 to raise the ring carrying the flanges 57, 58 to reset the detents 54, 55 in inoperative position. On the return stroke, the handle frees the arm 62, and then rocks the universal bar 19 to raise the plate 16 set by the succeeding stud 20 on the drum 21 in order to put another pair of detents 54, 55 into operative position. The depressed key in the keyboard is then released, and the operation repeated for the subsequent letters of the message.