Patent GB-410663-A (GB)
Title: Improvements in and relating to printing telegraphs applicable in particular to ultra-rapid telegraphy
IPC: H04L27/26
Filed: 1933-09-08
Abstract: 410,663. Type - printing telegraphy. SOC. FRANCAISE RADIO-ELECTRIQUE, 79, Boulevard Haussmann, Paris. Sept. 8, 1933, Nos. 24918, 24919, and 24920. Convention dates, Sept. 28, 1932, March 28, 1933, and May 11, 1933. [Class 40 (iii).] In a printing-telegraph system in which each character is constituted by current of a single frequency or of a plurality of superimposed frequencies and in which the type-selecting mechanism is controlled by magnets energized by relays each of which is selectively operated by a signal current of a predetermined frequency, the relays are arranged to lock in the operated condition after the cessation of the corresponding signal current and to be restored to normal under the control of local apparatus. The frequencies received are applied to tuned circuits 3, 4 controlling the grids of thyration valves 5 and to a valve 10 which passes current when any frequency is received to an electric coupling 11 through which a shaft 13 is coupled to a motor 12. Magnets 6 in the anode circuits of the valves 5 operate shafts on which are mounted detent members 21 which in pairs normally engage notches in pivoted operating members 19 controlling the type-levers 15. Each member 17 is engaged by two latches 21 corresponding to the two frequencies constituting the character signal associated with its type-bar 15. On the reception of a signal, the shaft 13 is set into rotation, and a cam 23 permits the unlatched member 19 to move under the action of a compression spring 22 to actuate the end of the associated type lever 15 against an inking ribbon 30 and the message tape 28. Each rotation of the shaft 13 operates a Maltese cross device 24 to rotate intermittently a shaft 25 which steps the printing tape 28 and the inking ribbon 30. For characters represented by a single frequency, the operating members 19 have notches corresponding to the total number of frequencies employed. The member 19 corresponding to a single frequency is normally latched and is released when this frequency alone is received. If an additional frequency is received, one of the latch members not normally in engagement is actuated to lock the member 19 against movement. In a modified arrangement, Fig. 4, the relays controlled by the thyrations are provided with a plurality of contacts connected so that on the reception of a combination of frequencies a circuit is selectively closed to one of the magnets 1, 2, 3 ...... 42 operating a type-bar or effecting carriage return, or line spacing. On the energization of any of the operating magnets 1 ... 42, a relay 43 operates to break the plate circuits of the thyration valves which have been in operation. Figure-shift and lettershift signals may comprise one frequency only, and the relays for effecting these operations may be arranged so that the operation of either relay opens the plate circuit of the valve controlling the other relay, Fig. 5 (not shown). In a further modification, Fig. 6, each of the operating magnets 1 .... 45 has two coils, which are in the plate circuits of different valves a ...... j, the magnets being such that they are operated only when current passes through the two coils simultaneously. The operation of any of the magnets operates a relay 47 opening the plate circuits of the valves a ... j. Case shift may be represented by a single frequency making the valve m conducting and operating magnet 46 which remains energized until the unshift signal operates the valve n energizing relay 48 which opens the plate circuit of the valve m. The plate circuit of the valve n is broken with consequent release of relay 48 when the relay 47 is again operated. In a modification of Fig. 6, Fig. 7 (not shown), the valves with the exception of the valve m may be fed from an A.C. source, thus obviating the use of the interrupting relay 47. The receiver may be combined with a keyboard transmitter in which the depression of a key controls the transmission of the appropriate frequency or frequencies, and prints the character transmitted.