Patent GB-190719699-A (GB)
Title: Improvements in and relating to Signalling and like Systems.
Filed: 1907-09-03
Granted: 1908-09-03
Abstract: 19,699. Allgemeine Elektricitõts Ges. Sept. 3, 1906, [date applied for under Patents Act, 1901]. Points. - An arrangement of switches, leads, and magnets for the electric power operation of signals and points prevents interference with the indicators or incorrect release of a lock or the like by stray currents. The main leads are either short-circuited or earthed through switches and contacts and the operation of the actuating or release gear is dependent on the action of these switches and contacts. The circuit of the control magnets 5, Fig. 1, in the normal position is closed from the battery 1 through the switch lever 2, 1 e a d 8, switches 12, 13 controlled by the operating-gear of the point signal, or locking-gear, lead 9, switches 3, 4 and the magnet 5, and lead 6 to the switch 10 controlled by the operating-gear, and to earth. When the switch lever 2 is moved, this circuit is broken, and the operating-circuit is closed from the battery 1 through the lever 2, lead 7, switch 11, and motor 14 to earth, and the switch 3 is moved to connect the magnet 5 to earth as the circuit of the magnet is broken and is held in this position by a catch, which is only released by the subsequent energization of the control magnets 5, which are now short-circuited. At the commencement of the motion of the operating-gear, the switches 12, 13 are moved to the left hand so that the lead 9 is also earthed. At the end of the motion of the operating-gear, the switches 10, 11 are moved to the left hand, and the motor circuit is broken. A circuit is then closed from the battery 1 through the lever 2, lead 7, switches 11, 10, lead 6, switch 4, and control magnets 5 to earth, and the energized magnet 5 raises the catch of the switch 3, which returns to the normal position and closes the control circuit through the lead 9 to earth. When the lever 2 is reversed, the switch 4 is moved to connect the magnets 5 to earth. The control circuit can only be closed when the contacts which make the earth connexion are properly earthed. In a modified form in which, if a stray current exists in a conductor, the associated locking-device is not affected, an accidental current, traversing the lead 1, Fig. 6, for the track-releasing magnets FF or the lead l<2> for the signal-releasing magnets SF does not affect these magnets because these leads are normally disconnected or earthed. The lead l<a> is completely disconnected, and the.lead l<1> is earthed through the positively operated switch 17 and the switch 19, which is operated by the control magnets SM. When the lever AH at the station is operated, a circuit is closed from the battery B<2> through the control magnets SM and from the battery B<1> through the track-releasing magnets FF at the cabin. The track point lever FH being operated, the control circuit is closed through the signalreleasing magnet SF. The track is released by the track switch (not shown) and the passage of the train over the insulated rail J S, and, when the track point lever FH is reversed, the control magnets SM are again energized. Each of the various switches used is brought into use by each movement of the track point lever and is thus tested as to its being in working order.