Patent GB-288300-A (GB)
Title: Improvements in or relating to electric signalling systems
IPC: H04L12/18
Filed: 1928-04-03
Abstract: 288,300. Fabrique d'Appareils Electriques Favarger Soc. Anon. April 5, 1927, [Convention date]. Order apparatus.-Relates to a signalling svstem wherein indications are displayed by a plurality of drums bearing characters and adapted to be controlled simultaneously by impulses which are transmitted under the control of a corresponding number of stepby-step switches and keyboard transmitters. The keys corresponding to the signal to be transmitted are depressed, and then a common key is operated to cause the transmission of the impulses and the operation of the receivers. In the system shown, three digits may be transmitted by operating corresponding keys in the banks S', S<11>, S<111>. Normally when the switch U is closed and no key is depressed the circuits of relays R', R<11>, R<111> associated with the banks of keys are closed through pivoted bars 15<1>, 15<11>, 15<111> and a relay R<4> is energized over the normal contacts m of stepping switches K<1>, K<11>, K<111>, the wipers of which are mounted on a common shaft 10 adapted to be driven by an electromagnetic ratchet mechanism SE. The contacts of each switch are connected to the contacts of the associated keyboard. Closure of the switch U also operates a motor M which drives a disc 12 adapted to control contacts 13, 14, in the manner described in Specification 224,872, to generate the signalling impulses. Depression of a key in each bank tilts the bars 15<1>. 15<11>, 15<111> to de-energize the relays R<1>, R", R<111> at contacts 20', 20", 20<111> and maintain the keys in the operated positions. The relays open contacts 22<1>, 22", 22<111> and prepare circuits at the contacts 23', 23<111>. The key TA is then operated to engage the stepping magnet SE and advance the wipers of the switches K<1>, K", K<111> one step to de-energize the rejay R<4> and prepare the impulsing circuit of a relay R<5> at the contact 27. The relay R<5> is impulsed by the contacts 13, 14 and at the contact 33 intermittently energizes the stepping magnets F<1>, F<11>, F<111> of the indicating drums T<1>, T<11>, T<111> over the operated contacts 23<1>, 23<11>, 23<111> of the relays R', R", R<111>. The magnet SE is simultaneously impulsed over the contact 33 to step forward the wipers of the switches K<1>. K<11>, K<111>. As soon as the wiper of each switch engages the contact marked by the operated key the corresponding relay R<1>, R<11>, or R<111> is operated to open the impulsing circuit of the associated receiver. The receiving drums are thus moved until they display indications corresponding to the depressed keys. The relays R<1>, R<11>, R<111> remain locked up over the contacts 22<1>, 22<11>, 22<111> to prevent further signalling after the wipers have passed beyond the marked contacts. the switch wipers operate through one revolution and upon arrival at the contacts m, relay R<4> is again energized to open the impulse circuit. The depressed keys are mechanically released by a key TM. A key TN is provided for zeroizing the receiver drums prior to further signalling. Upon operation, relay R6 is connected in series with the impulsing contacts 13, 14, and at the contact 38 energizes a. relay R' and the auxiliary coils V<1>, V<11>, V<111> of the receiver stepping magnets. In this manner the drums are stepped into their zero positions, contacts 43, 44, 45 in the resetting circuits being opened mechanically when these positions are reached. Several groups of receiving drums may be operated by a single transmitter by the provision of a group selector switch.