Patent GB-828445-A (GB)
Title: Improvements in or relating to cryptographic coding and/or decoding apparatus
IPC: G09C1/08
Filed: 1956-05-28
Abstract: 828,445. Coding. ANSTALT EUROPAISCHE HANDELSGESELLSCHAFT. May 28, 1956 [May 26, 1955], No. 16430/56. Class 146(2) In a cryptographic coding and/or decoding apparatus comprising at least one movable character-bearing member 8 to indicate and/or record the result of a coding &c. operation, a transmuting mechanism to rotate member 8 through an angle depending on the setting of a plurality of control members 93, 108 each time the apparatus is actuated, and a key mechanism for determining anew the setting of the control members at each actuation, the transmuting mechanism comprises a series of discs 9 and 22-26 individually rotatable about a common axis, and a further stationary disc 14, the first rotatable disc 9 being connected to member 8 and each rotatable disc being angularly compatable to the adjacent disc by engagement of a self - engaging latch 33 which is disengageable under control of members 93, 108 and each rotatable disc is adapted to rotate relatively to its adjacent disc; when released by its respective latch, through an angle limited by co-operating abutment means 27, 38 on the discs. The letters of the alphabet are set out on a stationary but replaceable ring 7 and on a disc 8 removably attached to a transmuting disc 9 and rotatable therewith, a character being shown, in clear on the ring and in code on the disc 8 or vice versa, and disc 8 being rotated by operation of lever 41 after each letter is coded or decoded. The total movement of disc 9 and hence the position of disc 8 relative to ring 7 is governed, by latches 33 which are controlled by a key disc mechanism or by a key tape mechanism. When lever 41 is moved inwardly teeth 40 rotate gear 18 and shaft 17, whereupon arm 19 rotates disc 9 with disc 8 and tensions spring 21. If the downward projecting lug 27 on disc 9 is already engaged with the latch 33 of the adjacent lower transmuting disc 22, or when such engagement is brought about by the rotation of disc 9 disc 22 moves with disc 9. Similarly when the lug 27 of disc 22 engages the latch 33 of transmuting disc 23 the latter joins the movement of discs 9 and 22, and so on until the lowermost transmuting disc 26 becomes coupled, by lug 27 and latch 33 to the fixed disc 14. The transmuting discs are then in the same angular position, i.e. the initial position. When lever 41 is released it is returned by spring means, and spring 21 then rotates disc 9 with disc 8. If disc 22 is latched to disc 9 it rotates therewith simultaneously, but if the latch 33 of disc 22 is disengaged disc 9 rotates relatively to disc 22 until the lug 27 of disc 9 engages a projecting arm 38 angularly adjustable on disc 22, the latter then rotating with disc 9. Similarly each disc 23- 26 is coupled for movement simultaneously with the upper adjacent disc if its latch 33 is engaged, or, if its latch has been disengaged, moves with the upper disc after the latter has moved to engage the associated arm 38. Disc 26 is arrested by latch 33 of the stationary disc 14 or by engagement with the arm 38 of that disc. Latches 33 are disengaged by movement of associated disengaging arms 93 of the key disc mechanism or disengaging arms 108 of the key tape mechanism, one or other of these sets of arms being held inoperative by selective engagement of a locking member 95 with notches 97 or 109 associated respectively with the arms 93, 108. Movement of lever 41 acts through pin 113 and slot 112 to move segment 110 with cam 111 so that bell-crank 114, 115 moves counterclockwise, Fig. 1, to permit counterclockwise movement of arms 93 or 108. Assuming that the key disc mechanism is operative, the feeler arms 92 with the connected arms 93 move counterclockwise to disengage their latches 33, unless prevented from such movement by engagement with an operative, i.e. projecting, lug 64 on the related key disc 52-57. At each double stroke of lever 41 pawl 78 acts through ratchet 77, driving wheels 71-76, and gear wheels 58-63 to rotate the respective key discs 52-57 one step to provide a changed control for arms 92. The lugs 64 are pivoted in slots arranged radially in discs 52-57 at the same pitch as the teeth of gears 58-63, and during assembly each lug is arranged, as desired, in an inoperative position wholly within its slot or in an operative position in which it projects from its slot. Adjacent gears 58-63 prevent movement of the lugs. The operative arrangement of the lugs may be changed by reassembly. If the key tape mechanism is operative the code perforated tape 101 is fed one step at each double stroke of lever 41 by means of a pawl 104, the disengaging arms 108 being freed by movement of lever 114, 115, and their associated feeler arms 106 engaging the tape. If an arm 106 encounters a perforation in the tape its associated arm 108 moves to disengage its associated latch 33, but if no perforation is met the arm associated 108 does not disengage the latch. At each actuation of the apparatus a counter mechanism is operated via gears 79, 80, 81. Disc 8 may be replaced by a type printing wheel. Disc 8 may carry two rows of characters which may be relatively adjustable angularly, ring 7 then being redundant. Ring 7 is readily removable for replacement by a ring with a different sequence of characters, or the characters may be carried on individually removable tablets. Disc 8 may be angularly adjustable relative to disc 9.