Patent GB-190313674-A (GB)
Title: Improvements in Electric Selecting, or Selecting and Signalling, Systems for communicating between a Central, or, Main, Station, and various other places, or Sub-stations, and for performing various operations at such places or Sub-stations
Inventor: SHEEHY ROBERT JAMES
Filed: 1903-06-18
Granted: 1904-05-05
Abstract: 13,674. Sheehy, R. J., and Curphey, A. G. June 18. Signalling and communicating between trains; controlling and locking signals; recording signals. -Relates to electric selecting systems in which an operator at a central station is able to communicate with any selected one of a series of substations on the same line-wire to the exclusion of the others. The selecting- devices may be employed in connection with telephone or telegraph systems, or for railway signalling purposes, and also for operating switch points on railroads &c. Figs. 1 and 2 are diagrams of the apparatus at the central station and at one of the substations respectively, L being the line-wire. A polarized relay PR is placed in the line circuit, and its tongue completes the circuit of the local battery LB through either of the electromagnets C, C<1>. These electromagnets operate a pole-changer a which puts either the positive or negative pole of the main battery MB to line. The combined action of the pole-changer and the polarized relay causes a constant vibration of the escapement lever B, thus sending a succession of alternating-current impulses to line, and also rotating the shaft C<2> and contactarm or "trailer" C<3> continuously. At each end of the substations, Fig. 2, a polarized relay PR<3> is placed in the line circuit, and its tongue serves to complete the circuit of the local battery LB' through the electromagnets I, I<1> thus vibrating the escapement lever I<2> and rotating the shaft K step by step in synchronism with the shaft C<2> at the central station. The " trailer " C<3> sweeps over fifteen contact-pieces independently connected to the plug switch 15<4> and to opposite sides of the switches 1<4> &c., and these fifteen contact-pieces are separated by a further series of fifteen pieces all connected to the detached plug switch 6<4>. Thirty contacts are thus made by the trailer during each revolution, and during this period thirty alternations are sent to line. If a plug is inserted in the switch 15<4>, the circuit of the battery LB is closad through the electromagnet C when the trailer passes on to the contact-piece 15. This holds down the armature of the escapement lever B in spite of the (less effective) pull of the electromagnet C<1>, which is at that time energized through the action of the polarized relay PR. All the shafts C', K, &c., therefore remain at rest until the plug is removed from the switch 15<4>, and the main battery continues with its negative pole to line. In this normal or unison position of the instruments, the contact-arms k at the substations are opposite to the contact-arms g<2>, and current passes from the local battery LB' through the wire g<1>, switch arm H<1>, indicator H', and wire g. The indicator then shows the signal "clear." In the arrangement shown in the Figures, there are seven substations on the line, and two special signals can be sent to each (for the direct operation of safety and danger signals for example), either of which also establishes line connection with the substation for ordinary telegraphic or telephonic communication. In Fig. 1, a Morse signalling-key is shown at Z, and telegraphic instruments are shown at X, Y. If the plug is removed from the switch 15<4> and inserted in the left-hand side of the switch 6<4>, the " trailer" will advance until it reaches the contact-piece 6, when it will be arrested by the completion once more of the local circuit through the electromagnet C, the main battery being, as before, with its negative pole to line. At all the substations, the shafts K will have been rotated equally, but at substation No. 6 the contact-arm k will have come to rest opposite the arm e<2>, thus closing the circuit of the local battery LB<2> through the electromagnet F, the armature f<8> of which is attracted. The movement of the armature f<8> effects the following operations :-(a) The line circuit is broken at f, f<1> and the connection re-madf through the armature f wire f<3>, "jack" f<4>, f<5>, wire f<6>, arm m, drum M, and wire f The plug Q can then be inserted in the " jack " f<4>, f<5> so as to put the local telegraphic or telephonic apparatus Q<1> in the line circuit. (b) A local circuit O<2> is closed, comprising an electromagnet 0 operating a semaphore signal, and also a signal bell 0<1>. (c) The circuit of the local battery LB' is closed at m<1> through the electromagnet N and contact-making device m<3>, with the result that the shaft N<2> and drum M make one complete revolution, during which time the drum interrupts the main circuit six times in rapid succession, the signal being repeated three times. This return signal indicates to the operator at the central station that No. 6 substation has been properly called up. While the line is thus in use, contact is broken at g<2> at all the substations, and the signal clear" is not shown. If the plug is placed in the right-hand side of the switch 6<4>, the contact-arm k stops opposite the arm f<2> and the magnet E is energized, thus operating through a circuit 0<3> another semaphore, or making a contrary signal. The " jack " e<2>, e<3> is in this case put in circuit. If a plug is placed in the detached switch 6<4>, the trailer stops on the nearest one of the fifteen contact-pieces connected with it and the positive pole of the main battery is put to line. Under these conditions, the tongue of the relay PR<3> remains permanently in its right-hand position, and the local battery LB<2> energizes the electromagnet U, thus putting the " jack " u<1>, u<2> in circuit at all the substations. A single plug and set of telegraphic apparatus may be used for all the " jacks." Local circuits u<3> are closed to give warning that a general call has been sent. A substation can call central by switching over at H, H<1>, thus putting the drum M into the line circuit and at the same time closing the circuit of the local battery LB' through the electromagnet N for the purpose of rotating the drum. A key R is provided for mechanically holding the escapement lever I<2> of a called-up substation against movement while a second station is being called up, so that the two can be put in communication. During any such communication, the instruments are out of step, but they can be restored to the unison position by allowing the '' trailer " to make three revolutions and then stopping it at the contact 15. A " unison releasing magnet" G at each of the substations controls the rotation of the shaft K so that it stops at the unison position g<2>. An emergency call box CB is provided at each substation, which enables an emergency signal to be sent to line without waiting for the establishment of the usual communication in response to a call. On railways in which the track is used for automatic signalling, the closing of the local circuit O<2>, &c., at the substation may be made to short-circuit the track, giving the same danger signal as if a train were on the line, or the rail circuit may be opened to give a signal on the train, or otherwise.