Patent GB-488337-A (GB)
Title: Improvements in or relating to coding and decoding machines
IPC: G09C3/00
Filed: 1937-10-01
Abstract: 488,337. Coding-machines. INTERNATIONAL BUSINESS MACHINES CORPORATION. Oct. 1, 1937, No. 26597. Convention date, Oct. 24, 1936. [Class 146 (ii)] In a coding and decoding machine of the kind described in Specification 481,983, and comprising a manually-operable primary machine, such as a typewriter, controlling a secondary machine through interposed adjustable coding-mechanism, the coding and adjusting mechanisms being displaced from a normal starting-position at each operation of the primary machine and being adapted to be reset to normal position, manually-operable selectively-positionable mechanism, which acts to set the adjusting-mechanism to a different starting-position on effecting a resetting- operation, is provided. As in the prior case, the adjusting-mechanism comprises a rotary switch 237 having three banks of contacts which are employed in moving the alphabet and numeral commutators 57, 55, and in the resetting-operation respectively. The contacts of the third bank of the switch 237, instead of being connected directly to the relay 276 acting to return the switch to normal position, are each connected to corresponding contacts in two banks of a rotary switch 500. The contacts in the second bank are adapted to be engaged by an arm 503, while those of the first bank are adapted to be engaged by points 506 on an arm 505, the points 506 at any time engaging all the contacts in the bank except the one corresponding to that engaged by the arm 503. The shaft 504 carrying the arms 503, 505 also carries a detent-wheel 507 to ensure correct positioning of the arms and to operate contacts 508 in the circuit 246. In normal operation with the parts in home position, actuation of the reset key RK before commencement of coding or decoding causes the energization of the relays 216, 220, 227, and the circuit 212, 218, 232, 104a, 233, 71, 234, 235, 235a, 236, first contact of the third bank of the switch 237, 510, 511, first contact of the second bank of the switch 500, 503, 241, 233, establishing the holding-circuit ... 234 244, 246, 508, 243, 223, illuminating the lamp 247, and de-energizing the relays 220, 227. The machine is then in condition for normal operation. If the machine were not in home position, operation of the key RK first resets the discs 59 and the alphabet and numeral commutators to normal position, and then establishes the circuit ... 235a, 236, contact to which the switch 237 has been moved, corresponding contact of the first bank of the switch 500, 505, 514, 370, 276, to move the switch step-by-step to home position, when the circuit through the arm 503 is established to illuminate the lamp 247 and indicate that the machine is in condition for normal operation. If it be desired to change the starting- position of the switch 237, the switch 500 is adjusted to the desired new position, the rotation of the wheel 507 breaking the contacts 508, and de-energizing the lamp 247. The key RK is then operated to cause the switch 237 to be adjusted to correspond to the new position of the switch 500 and to illuminate the lamp 247.