GB108213A - Improvements in Electrical Signalling Apparatus for use in Mines, and for other purposes. - Google Patents

Abstract

108,213. Waddington, H. R., and Parsons, I. H. Aug. 7, 1916. Mine signalling systems; order and order-type apparatus.-In a signalling system wherein the sending of a signal cancels the previous signal, each of the receiving devices is provided with a relay having an operating coil and a retaining coil or a single coil serving both purposes. In the common return of the operating coils is connected the coil of a switch placed in the common return of the retaining coils, said switch being momentarily opened to break the retaining circuit of the previous signal and again closed to retain the new signal. In the arrangement shown in Fig. 1, each of the lamps D or other visual indicators is controlled by a relay E having an operating coil F and a retaining coil G. In the common return of the operating coils F is connected a switch coil N and a single stroke bell S. The armature 0 of the coil N operates a switch Q, Q<1>, in the common return of the retaining coils G, through a pawl O<2> and a star-wheel P. The switch Q, Q<1> is normally closed, but as a tooth of the wheel passes from under a block Q<4>, the switch is opened until the next tooth of the wheel engages the block Q<4>. The momentary opening of the switch Q. Q<1> breaks the circuit of the retaining coil and lamp of the previous signal, while the closure again establishes the circuit for retaining coil and lamp of the new signal. The signal circuits are controlled by switches C, and a clearing switch R is placed in the circuit of the retaining coils. The windings F and G may operate separate linked armatures. The switch Q. Q<1> may be operated by a pivoted member O<2>, Fig. 3. which rides over the projection Q<4> to open the switch when the magnet N is energized but which swings about its pivot O<3> when the magnet N is de-energized in order that it may not operate the switch. The switch is provided with carbon arcing contacts Q<2>, Q<3>. In the modification shown in Fig. 2. each relay E is provided with a single coil F' and its operative circuit closed by a switch C, while its retaining circuit includes a battery B and the contacts L, L<1> and Q, Q<1>.