Patent GB-180632-A (GB)
Title: Device for automatically substituting one source of light for another, particularly in connection with light-houses
IPC: F21V19/00
Filed: 1922-02-22
Abstract: 180,632. Anciens Etablissements Bar bier, BÚnard, et Turenne, Soc. Anon. May 21,1921, [Convention date]. Convertible gas, electric, and like lamps.-Relates to arrangements for the automatic substitution of a non- electric light for an electric light on failure of the latter, and for the reverse substitution, particularly applicable to lighthouses &c., the arrangement being such that where an intermittent light is used the device is not operated by such intermittent extinction of the electric light. In the parforms described, arrangement is also made whereby the replaced light is automatically removed from, and the substituted light brought into, a particular focal point of the optical system. The principle of the device is illustrated diagrammatically in Fig. 1. An electromagnet H in series with the electric lamp L has two parallel windings f, g of high and low resistance respectively, the former being permanently in circuit, and the latter connected in shunt therewith intermittently by a contact m operated by a cam K. Adjustment is made so that normally either or both of the coils, when energized, retains the armature B, but when the voltage falls, or the lamp circuit is broken by breakage of the lamp filament, or voluntary operation of a switch, the armature is released. Armature B operates contacts controlling the circuit of an electromagnet F which effects the substitution by means not shown. Alternatively, the substitution may be effected by the armature B. Slightly modified arrangements of the windings f, g and contact m, and modification for use with alternating current, are described. Fig. 6 shows an application of the device. The lamp L and a gas mantle T are mounted on a pivotal support Y. A counterweight W tends to bring the mantle into the position occupied by the lamp L at the focus of the optical system. The solenoid F is normally energized and a link G connected with the sclenoid core serves to hold the support in the position shown. The cam K operating the contacts m also serves to operate a valve M to give the gas light the same intermittent action, in use, as is given to the electric lamp. On failure of current in the lamp-circuit, the solenoid F' releases its core, the lamp L is replaced by the mantle T, and the gas supply is established through ports Y<2>, Y<3>. In the position shown, the burner T is kept alight, by a pilot burner (not shown). A modification is described in which the electric lamp and burner are carried by an horizontal disc. The disc is rotated through a half-turn in one direction by a motor, and is returned by a spring, the movement of the disc being limited by stops. A finger on the disc cooperates with the core of the solenoid F, and projections on the disc serve to control contacts in the motor circuit, and to operate the valves of the gas supply. In a further modification, using an horizontal disc, the disc is rotated in one direction by a weight acting on a cord, and in the other direction by a cord operated through a pivoted arm by a diaphragm closing a chamber through which the gas supply passes, the gas light being retained in use in the desired position as long as the pressure of the gas in the chamber is maintained.