Patent GB-418996-A (GB)
Title: Improvements in or relating to illuminating apparatus for lighthouses, beacons and the like
IPC: F21V19/00
Filed: 1933-05-03
Abstract: 418,996. Lighthouse, beacon, &c. lamps. GAS ACCUMULATOR CO. (UNITED KING- DOM), Ltd., and GOODWIN, G., Beacon Works, Brentford, Middlesex. May 3, 1933, No. 12959. [Classes 75 (i) and 75 (iv).] Convertible gas and electric lamps; burners, mounting.-In a lighthouse, beacon, or like lamp in which either or both the normal and emergency sources of light utilize a fluid illuminant, and the latter is employed to effect automatically the replacement of the normal source by the emergency source when necessary, the replacement apparatus includes a member responsive to the pressure of the fluid illuminant and connected to a double acting fluid control valve associated with means for actuating it at predetermined instances of time under the control of electromagnetic or like restraining means. In the form shown, the normal source comprises an electric lamp bulb 1 at the focus of the optical system of the lamp and the emergency source comprises an acetylene burner 3, these two sources being carried by the radial arms 4, 5 of a carrier 6 which is pivotally mounted on a pedestal 8 and biassed by means of a counterweight 9, a recessed extension of the carrier being adapted to engage a stop 10 on the pedestal. The bulb 1 is connected in circuit with a source of supply 15, a main switch 16, a second switch 18 on a clockwork timing mechanism 19, an electromagnetic device 40, and a flashing device 17 comprising an intermittently shortcircuited ohmic-resistance in shunt with a a resistance 46. Acetylene gas from a reservoir 24 passes partly to a byepass burner 38<a> and partly tc a selecting device 25 from which it may pass partly through a flashing device 35 to the burner 3 and partly to a chamber 13 in which is seated a diaphragm 12 to which is pivotally connected a roc 11 for rocking the carrier 6. When neither source of light is required to be illuminated the actuating member 20 of the timing device 19 is engaged with the stop 21. When the member 20 is engaged with the stop 22 the switch 18 is closed and the bulb 1 illuminated. At the same time a lever 42 pivotec on the member 20 engages the stem 30 of a two-way valve in the selecting device 25, but is prevented from exerting any pressure thereon by means of the electromagnetic device 40. No gas is therefore supplied to the valve chamber 29 and an outlet 39 opens the chamber 13 to the atmosphere so that the diaphragm 12 and the rod 11 remain in the position shown. If the bulb 1 or the electric supply fails, the electromagnet 40 is de-energized the armature 41 is biassed away from the core 43 by means of a spring 47, and the lever 42 depresses the valve stem 30 against the action of a spring 31. The outlet 39 is closed and gas passes through the flashing device 35 to the burner 3 and into the chamber 13. The diaphragm, 12 is raised by the pressure of the gas, the carrier 6 is rotated, and the burner 3 brought into the focus of the optical system of the lamp. When the electric circuit is again completed the electromagnet 40 is energized and the bulb 1 returned to its original position. Modifications described in the Specification include replacing the clockwork timing mechanism by a lightsensitive valve and an associated diaphragm chamber, replacing the rod 11 by a rack engaging a pinion secured to the carrier 6, and mounting the two sources of light for linear movement by means of a fluid-operated piston.