Patent GB-481983-A (GB)
Title: Improvements in system of coding and decoding
IPC: G09C3/00
Filed: 1936-10-31
Abstract: 481,983. Coding - machines. INTERNATIONAL BUSINESS MACHINES CORPORATION. Oct. 31, 1936, No. 29679. Convention date, May 22. [Class 146 (ii)] A coding and decoding machine comprises a manually-operable typewriter controlling a secondary typewriter through mechanism which is adapted to be set at odd intervals to change the code and in which the sequence of connections to and from the mechanism can also be changed automatically at irregular and arbitrary intervals. The two typewriters are electrically controlled through keys which, on actuation, close corresponding contacts. Each carriage comprises a conducting-bar 34, 34a, Fig. 17A, engaged by brushes 36, 36a respectively connected in parallel, the bars being formed with notches exposing an insulating-bar so that the circuits through the brushes are disconnected when the carriage is in the starting-position and after forty-five and fifty-three actuations of the keyboard. Each key is adapted to be actuated automatically by a solenoid, and is provided with a projection adapted to lock the keyboard so that only one key can be actuated at once. The coding- mechanism is driven from a continuouslyrotated shaft 48, Fig. 1, through clutch mechanisms 51, 51a, 51b, each of which is controlled by two electromagnets. In de-energization of one of these electromagnets, the clutch mechanism is actuated to rotate the associated shaft 54, 56, 58 one-quarter revolution ; the other electromagnet causes continuous rotation of the shaft. The control device consists of a number, e.g. twelve, of discs 59 mounted on a shaft 60a driven by the shaft 54, the discs being formed at the edges with notches, preferably three hundred and sixty in number, and being driven at each quarter rotation of the shaft 54 through the distance separating the notches. Stops are arranged arbitrarily in the notches and are adapted to close corresponding contacts 65, Fig. 17B. A gear-wheel 60 on the shaft carries cam surfaces so arranged that contacts 71 are closed only in the home position of the apparatus, contacts 70 are open only in the home position, and contacts 69 are open in the home and two preceding positions. The letters and signs to be coded are adapted to be scrambled separately by commutators 57, 55 respectively mounted on the shafts 58, 56. The commutator 57 comprises brushes connected to the contacts associated with the letter keys of the primary typewriter, and mounted on a fixed insulating-ring 75. The brushes engage segments secured to the shaft and connected to slip-rings 78 also secured to the shaft and engaged by brushes connected to the solenoids of the secondary typewriter. A movable insulating-ring 81 carries brushes 82, 83, Fig. 17, engaging slip-rings 84, 85 secured to the shaft. The ring 84 is provided with one conducting segment engaged by the brushes 82 when in the home position ; the ring 85 has conducting segments engaged by the brushes 83 in all but the home and two previous positions. The ring 81 is moved forward on the de-energization of a magnet 90; energization of the magnet opens normally-closed contacts 97. The ring 81 is formed with a notch which, in the home position, closes contacts 116 and opens contacts 117. The commutator 55 comprises brushes connected to the numeral-key contacts of the primary typewriter, and, through segments, slip-rings, and brushes, to the numeral-key solenoids of the secondary typewriter. The shaft 56 carries a number of spaced cam discs 104- 108, Figs. 1 and 17, each formed with recesses which permit the operation of contacts 104a- 108a; the recess in the disc 104 also causes the opening of contacts 104b. The recess in the disc 104 is engaged only at the home position ; the recess in the disc 105 is engaged at the home and two previous positions ; the recesses in the discs 106-108 are arbitrarily arranged and control the energization of relays 130, 190, 191 which act to vary the sequence of the connections between the primary and secondary typewriters. Two main control keys CK, MK, Fig. 17A, are provided. The key CK has two positions, one for coding and the other for decoding. The key MK has three positions, in which (a) during coding, a space is automatically inserted by the secondary typewriter after every fifth letter and the space bar of the primary typewriter actuates a character key of the secondary typewriter, and, during decoding, the primary typewriter space-bar and the automatic spacing-mechanism are disconnected; (b) during coding, automatic spacing is provided for, but tho space-bar of the primary typewriter is not used, and, in decoding, the space-bar is disconnected ; and (c) the contacts are set for the typewriters to operate in unison. At the commencement of the typing of any line, the carriage return key is locked against actuation until forty-five or fifty-three actuations (i.e. forty-five characters and eight spaces) of the secondary typewriter carriage have been effected; at this point, the remainder of the keys are locked and are only released after the carriage has been returned. After the typing of a group of lines, the machine is locked and a lamp is energized to indicate that a check is necessary, this being effected by actuating a test key to release the locks, print a full-stop, and return the carriages. If an error occurs in the movements of the carriages, the keyboard and carriage return keys, and, if in the last line of a group, the test keys, are locked; an error key must then be actuated to set the machine back to the position at the end of the previous group test and to print a symbol indicating the line in which the error occurred. Actuation of the test key results in the stepping forward of a coding-control unit, such as a rotary switch, to effect connections through different circuits. A reset key is provided for returning the machine to starting-position, and means for changing the starting-position is also provided. A reset operation is necessary in order to initiate coding or decoding irrespective of the position of the coding-units. In use, the switches 210, 211 are closed, connecting the battery 212, Fig. 17, through the conductor 213, brushes 82, single conducting segment of the ring 84, to relay 216. The key RK is now operated to close the circuit 212, 221, 222, 220, 219, opening contact 225 to disconnect the battery from the relays 130, 190, 191, and closing contact 226 to establish a holding circuit for the relay 220. The circuit 212, 218, 232, 104a (closed in home position of the machine) 233, 71 (also closed in home position) 234, 235, 235a, brush 236 of the third bank of contacts of the rotary switch 237, home contact 238, 241, 223 is established, establishing a holding-circuit for relay 223, illuminating the lamp 247, and opening the contact 222 to de-energize the relay 220. Operation of any key in the keyboard closes common contacts 250, Fig. 17A, making the circuit 212, 221, 230, 252, 253, 255, contacts 256 of MK key in first position, 250, 257, 258, the relay 25.8 controlling the clutch 51 and causing the control discs 59 to be stepped on when the contacts 250 are opened and the relay is de-energized; this effects opening of the contacts 71 and de-energization of the lamp 247. The circuit 212, 221, 225, 282, 283, 285, 106a-108a (one only of which is closed at every position of the commutator 55), 130 (190 or 191) is now closed to provide a typing circuit between the typewriters. When the typewriter carriages move on the first operation, the circuit 212, 221, 222, 224, 261, 36 or 36a, 34 or 34a, 262, 260, 273, 264 is established, opening contact 266 of test key TK, and establishing circuit 261, 268, 269, 270, 272, 267, to solenoid 42b which actuates the carriage return lock. When the discs 59 have been moved sufficiently far the stops thereon close one or more contacts 65 connected to a common conductor 275 and arbitrarily to the contacts in the three banks of contacts of the rotary switch 237. When a circuit is established through one of the contacts of either the first or second banks of the rotary switch, relays 279, 288 are energized to move forward the alphabet and numeral commutators 57, 55 respectively, movement of the commutator 57 effecting disconnection of the circuit through the brushes 82. After each fifth operation of the keyboard in coding, one of the discs 59 closes the contacts 65 to connect the circuit from' the battery 212..255, 256, 280, 281, 154, 155, 156 to the space solenoid 42. After forty-four actuations of the keyboard, contacts 65 are operated to make the circuit 212..255, 256, 257, 275, 289, 290, 292 to close the circuits 212, 221, normally-closed contact 295, 242, 296, 291, 294, 292, and 212, 221, 222, 224, 261, 268, 269, 270, 272, 293, 297 to lock the keyboard except for the carriage return key. At this time, the circuit through the brushes 36, 36a should be broken by engagement of one brush of each pair with a notch in the conducting bar, so. that the solenoid 42b locking the carriage return key will be de-energized. Actuation of the carriage return key will effect the return of the carriage of the primary typewriter, close contacts 300 to energize the solenoid 301 controlling the carriage of the secondary typewriter, and open the contacts 295 to deenergize the solenoid 297. To provide a check at the end of a group of lines, the last keyboard operation of the group closes a circuit to energize solenoid 297, and a circuit 302, 303 to relay 304 whereby the circuit 261, 268, 269, 270, 272, 305, 308 to solenoid 42b is closed. The circuits to a signal lamp 309 and a relay 254 are also closed. Energization of relay 254 (a) closes the circuit 212, 221, 225, 282, 284, 312, 311, 313 to disconnect the circuit to the relays 130, 190, 191 and close the circuit to the relays 124, 124a, so that the key contacts of the primary typewriter are connected to the corresponding solenoids of the secondary typewriter; (b) opens the contact 253 so that