Patent GB-190610507-A (GB)
Title: Improvements in Railway Signalling Apparatus.
Inventor: RAVEN VINCENT LITCHFIELD
Filed: 1906-05-04
Granted: 1907-06-20
Abstract: 10,507. Raven, V. L. May 4. Signals on engines; contacts, electric. - In apparatus of the kind in which audible and visual signals on the engine are electro-magnetically controlled as contact-brushes pass over fixed track contacts, the circuit between two such brushes is closed by passing over a bar in advance of the signal to give a warning of the approach to the signal, and the visual and audible warning signals are continually given until the train arrives at fixed contact-bars adjacent to the signal when 'safety' or 'danger' indications are then given by these engine signals. In various modifications, the arrangements for use with 'distant' and 'home' signals and at a branching track are described. Fixed track contact-bars 9, 10, Fig. 1, are provided between and parallel to the track rails 15, and the insulated bar 10 is connected to earth when the adjacent signal 8 moves to line clear' and closes contacts 13, 14, which connect the bar 10 with a track rail 15. Brushes 6, 7 on the engine are connected to a battery 11, and a magnet 3 and a bell 5 are arranged in shunt circuit, while another magnet 4 is connected to the brush 7 and to an earthed battery 12. On approaching the signal 8, the bar 9 connects the brushes 6, 7 and closes the circuit through the magnet 3, the bell 5, and the battery 11, and gives a warning signal of the approach to a semaphore, the miniature signal 1 being raised by the attracted armature 18. Contacts 24, 25 are also closed by this action to close a local circuit through the battery 11, the magnet 3, and bell 5, which continue to give the warning signal until the track bar 10 is reached. If the signal is still at 'danger,' the bar 10 is insulated, and the conditions on the engine are unchanged, but a 'line clear' indication provides for the earth connexion of the bar 10 as above, and the brush 7 is connected to earth, thus energizing the magnet 4 through the earthed battery 12. The attracted armature 29 breaks the circuit of the magnet 3 and the bell 5 at the contacts 27, 28, the bell 5 stops sounding, and the miniature signal 1 drops. In a modified form, the battery 12 is included in the earth connexion of the bar 10, and is provided at each track bar 10, thus obviating false indications by the accidental earth connexion of the bar 10. In another form, the magnet 4 is dispensed with, the 'safety' indication being given by short-circuiting the magnet 3. In this form, as the brush 6, Fig. 3, passes over the earth-connected contact-bar 9, the magnet 3 and the bell 5 are energized through the lead 16, and the connexion to the electric-supply lead 11<a>, the opposite terminal of the source being also earthed. Here again the contacts 24, 25 are closed to include the magnet 3 and bell 5 in a local circuit, which keeps the warning-signal in action until brushes 6<a>, 6<b> pass over the track bars 10, 10<a>, which may be connected together by the closure of contacts 13, 14 if the signal 8 is at 'clear.' In this case, the bell 5 and magnet 3 are de-energized by the short-circuit through this closed circuit, and a 'line clear ' indication on the miniature signal results. If, however, the signal 8 is at 'danger,' these contacts 13, 14 are open, and contacts 32, 33 are closed connecting the additional bars 34, 35 to earth, so that a brush 36 next passes over either the track bar 34 or the track bar 35, according to the direction of travel of the engine, and energizes the magnet 41 through the leads 45<a>, 45 to the supply lead 11<a>. The magnet 41 attracts its pivoted armature 43, which allows a lever to fall, opening an attached valve 40 in a pipe which leads from a whistle 37 to the Westinghouse-brake pipe 38, or the vacuum-brake pipe 39, thus giving an additional 'danger' signal. This modification is especially suitable for electrically-propelled vehicles, and the apparatus may be duplicated with a single set of brushes, one set of apparatus being provided at each end of the vehicle. In another modification, the magnets 3, 4, shown in Fig. 1, are duplicated for 'home' and 'distant' signal indications, and are connected to two pairs of brushes engaging separate track bars f or 'home' and' distant' signal indications, the energizing batteries for the magnets 4 being situated on the track adjacent to the respetive signals. This arrangement is further modified for home and distant signal indications at a junction of two tracks. Two polarized indicators are introduced into the circuits to indicate the road signalled, and their currents are derived from a single battery at the 'distant' signals and 'home' signals, the direction of the current being made to depend, by means of the signal-controlled electric switches, upon which the signal is operated. In this case, as in the previous modification, the home-signal track bars may be connected in series to one or more similar sets of track bars, extending between the 'home' and 'distant' signals, to give early warning to an approaching train of the condition of the 'home' signals.