Patent GB-191406180-A (GB)
Title: Improvements in or relating to Electric Switch Apparatus for use in connection with the Electric Lighting and Heating Equipments of Railway and other Vehicles.
IPC: B60L1/00
Filed: 1914-03-11
Granted: 1915-03-11
Abstract: 6180. Electric and Ordnance Accessories Co., and Etchells, J. March 11. Electro-magnetic switches.-Relates to switch apparatus of the kind described in Specification 27,010/11, wherein a contact-brush for completing electric lighting or heating circuits in railway vehicles is operated by a solenoid plunger and latched by an electro-magnet armature, and has also means for operation by hand. The invention consists in an arrangement whereby the solenoid and the latch electromagnet are both controlled electrically from a distance by means of a master switch, the electrical release of the plunger being effected only upon simultaneous momentary excitation of the solenoid and the latch-magnet. In the arrangement shown in Fig. 1, the switch is used to connect a battery with lamps and is controlled by a master switch L. To close the switch, the arm of the master switch is set on to its contact l<1> making circuit through the solenoid A which raises the plunger B attached to the main brush C. A shoulder b on the plunger B takes over the end of the latching armature E and the main switch remains closed after the master switch has been brought back to zero. To effect the opening electro-magnetically, the master switch arm is set on to the contact l, the solenoid A and the electro-magnet F are energized, and the circuit is then broken at the master switch, and the plunger and contact fall. For the purpose of manual operation, the lower end b<1> of the solenoid plunger is prolonged and fitted with a loose sleeve M. To close by hand, the lower end of the plunger is pushed up leaving the sleeve unmoved. To open by hand, the sleeve is raised without the plunger. In the arrangement shown in Fig. 3, two switches are employed for obtaining full-light and half-light effects. The two switches C, C<1> are respectively closed by setting the contact of the master switch L on to the contacts l, l<1>. The solenoid winding of each switch is in series with the unlatching electro-magnet of the other switch but the weight of the plungers prevents the release of the catches. To open, the master switch is momentarily set on the contacts l, l<1> simultaneously, thus energizing and de-energizing both solenoids and electro-magnets. In a modification, the circuit arrangements of the two solenoids A, A' and the two unlatching electro-magnets F, F<1> are so shown in Fig. 4. When the master switch is momentarily set on to one of its contacts both switches are closed and one is immediately released owing to the energization of its solenoid and unlatching electro-magnet, the other unlatching magnet not being energized because the current divides into two parts flowing through halves of the magnet in opposite directions. When the master switch is momentarily set on both contacts simultaneously both solenoids and unlatching magnets are energized and de-energized and both switches are opened. In further modifications, one of the switch brushes is disposed above its fixed contacts so -that, in the down position of its solenoid plunger, the halflight circuit is normally closed, and the masterswitch circuits are arranged so that the change from full-light to half-light can be made without opening both switches in between. The latter modification may be used in parallel with the switches described in Specification 5012/11.