GB461397A - Transmitter and receiver of impulses for long distance transmission - Google Patents

Abstract

461,397. Electric signalling systems. SOC. POUR L'AFFRANCHISSEMENT ET LE TIMBRAGE AUTOMATIQUES, and BOYE, A. April 9, 1936, No. 10496. Convention date, April 9, 1935. [Class 40 (i)] In a signalling system in which a number of indicators are set by a series of impulse trains, the trains are distributed to the indicators by a selector switch which is stepped by a slow-torelease relay at the end of each impulse train. The selector stands normally on a blank contact and is stepped to connect with the first receiving indicator by an impulse transmitted before the normal trains commence. When the trains have terminated the selector stands on a position which connects the magnets of all the indicators in parallel so that a resetting train resets all the indicators, the circuits being broken by offnormal contacts when the indicators are restored. As shown, indicators at the transmitting station are operated by the transmitted pulses to check the transmission to the distant receiver. The transmitter A is of the type described in Specifications 381,532, 390,385, and 402,355, [all in Group XXXIX], and comprises an impulse generator 2 and three cam discs a1, a2, a3, each of which controls the transmission of two trains of impulses. When a transmission is initiated disc a1 rotates and spring-pressed pawl 8 enters in turn the notches 14, 11 and 12, Fig. 2. When the pawl swings it moves rod 6 to the right and contacts 3 close to allow impulses to pass to line. The impulse train controlled bv notch 14 is used only to energize magnet R at the remote and local receivers so that when the train terminates R releases and steps the selector switch CS. The notch 11 is of such a length that the impulses during the passage of the notch past pawl 8 are equal to the first digit. To this train magnet r1 responds and indicator b1 is set. Magnet R, which energized in parallel with magnet r1, releases during the break caused by projection 13 and the selector CS is stepped onto contact c2. The next impulse train sets indicator b2 and when it terminates magnet R again steps the selector. When pawl 8 is deflected by projection 16 it forces arm 18 downwards to release the second transmitting disc a2 and the second two digits of the signal are transmitted. The disc a3 is similarly released when the next pair of digits has been sent. At the end of the last digit the selector switch wiper is moved into the vertical position in which circuits are closed to all the magnets r1-r6 in series with their respective off-normal contacts d1-d6. To reset the apparatus, therefore, the contacts 3 are closed to allow transmission of a long impulse train so that the indicators step simultaneously until their respective circuits are opened at their off-normal contacts. When the train terminates, magnet R steps selector switch CS into its normal position. The switch C is provided to connect the call-bell 24, the receiver B, or the transmitter A to line L as required, the receiver B being connected in parallel with the line when the transmitter A is connected up.