Patent GB-499209-A (GB)
Title: Improvements in or relating to printing telegraph systems and apparatus
IPC: H04L17/26
Filed: 1937-07-16
Abstract: 499,209. Type-printing telegraphy; printing telegraphs. CREED & CO., Ltd., and MASON, F. P. July 16, 1937, Nos. 19739 and 28869. [Class 40 (iii)] [Also in Group XVI] In a printing telegraph system a typecarrier is moved to a position corresponding to a received impulse combination either by an electromagnetic force of magnitude characteristic of the combination or by a number of forces characteristic of each received impulse and its sequential position in a combination, the forces in this case being combined to produce displacement of the type-carrier. A coil A, Fig. 1, of an instrument similar to a dead-beat moving-coil galvanometer, Fig. 6 (not shown), is connected in series with a number of parallel resistances 6, 7, 8, 9, 10 controlled by individual switches 1, 2, 3, 4, 5. The magnitudes of the resistances are in the proportion, 16, 8, 4, 2, 1 and the switches are closed or left open by means of relays selectively operated by the successive received impulses. The total current passed through the coil A is thus of magnitude characteristic of the received combination. Alternatively the instrument may be fitted with separate windings, the number of turns being in the proportion 16, 8, 4, 2, 1, equal currents being passed through them selectively, Fig. 2 (not shown). In order that the total resistance of the circuit may remain substantially constant, switching arrangements, Figs. 4, 5 (not shown), may be inserted to provide for retaining the resistances in the main circuit when their effect on the instrument A is removed. In one embodiment of the invention applied to reception of five unit code, the received impulses selectively control the charging of individual condensers, acting as storage devices, by means of a distributer. Individual switches close simultaneously after receipt of the fifth impulse and connect the condensers to individual gas-filled discharge tubes which, if operated, pass current through resistances of magnitudes in the proportion 16, 8, 4, 2, 1, the total current being passed through the moving coil to position the type - wheel. For printing, a type-wheel 61, Fig. 9, is slidably mounted on the type-shaft 94 and, after each setting, is struck by a block 66 on a pivoted printing hammer 67 which is depressed and quickly released by a printing cam 46, while, at the moment of striking, a tooth 68 on the hammer 67 engages a positioning wheel 65 on the type-shaft. During the downward movement of the hammer ratchet tape feeding mechanism 71, 73, 74 advances the tape 75 one space. In each of the two type-shaft positions corresponding to a case shift signal one of two pins 81, 82 on the type-shaft 94 engages one of the upper arms of a three-armed lever 69 pivoted on the printing hammer when the latter tends to return for the printing operation. The lever 69 is thus tilted in the appropriate direction so sliding an attached bar 76 to the right or left. On the next downward movement of the hammer a projection 77 on the bar 76, by engaging one or other of two surfaces 78, 79 on a lever 62 pivoted at 80, tilts the lever 62 clockwise or anticlockwise so that two pins 63 carried by it, by moving a flange 64 mounted on the typewheel 61, bring the appropriate row of type over the printing block 66. Specification 469,810 is referred to.