GB239562A - Improvements in or relating to synchronous telegraphy - Google Patents

Abstract

239,562. Foll, J. V. April 10, 1924. Curbing at transmitter; repeating sytems using contact-making relays; restoring or modifying imperfect signals; synchronous movements and synchronism indicators; distributor systems. -In a system of synchronous telegraphy the recording or repeating of the signals is controlled by synchronized mechanically-driven contactmaking apparatus which determines mechanically both the beginning and the end of the signals. The invention may also be applied to the control of primary manual transmitter. A set of continuously-driven cams is employed for this control. The actuation of repeating relays h<1>, h<2> depends not only on the position of the main relav A but also on the closure of a contact c<3> by a pick-up cam C which shortens resistance c<6>. A repeating cam D driven by the same gear wheel G acts on levers d<1>, d<2> to move biassing rollers d<6>, d<7> into or out of the path of the levers H, H<1> actuated by the electromagnets h<1>, h<2> and so determines the percentage of marking of the repeated signals. The repeating cam D may also act as the pick-up cam and in systems without a zero one of the levers H, H<1> and one of the electromagnets h<1>, h<2> may be omitted. The system may be provided with a key M for manual transmission, a switch m<2> enabling the transmitter to be cut into and out of the circuit. The keys m can only be operated when released by magnets m<1> the circuits of which are closed at c<4> by the pick-up cam C. This manual transmission method may also be employed in a primary manual transmitter to enable synchronism to be maintained. The invention may be adapted to a system in which the signals received are sent successively into two or more lines by multiplying the cam D and the mechanism it operates, whilst a corresponding number of levers and contacts is operated by the pickup cam C to short-circuit resistances ensuring that the received signals are sent successively into the various lines. Cams E, F are employed to indicate and maintain synchronism. The motor gear wheel G is driven slightly faster or slower than is required for synchronism and the cam E closes a circuit for a correcting-device of known type. The cam F driven at half the speed of the remainder closes in succession the circuits of lamps j which are completed intermittently through the contact lever l of the electromagnet L energized by the battery K<1> under the action of the incoming relay A. When the lamps light up in proper order the instrument has been adjusted to signalling speed. Cams C, D, E may alternatively be arranged on a common shaft and cam F driven by a gear wheel on the same shaft.