GB405248A - Improvements in or relating to photographic flashlight lamps - Google Patents

Abstract

405,248. Flashlight lamps. HARKER, J. A. M., 28, Victoria Street, London. June 23, 1932, No. 17794. [Class 75 (i).] Flashlight lamp bulbs or vessels containing a mixture of combustible gases, a decomposable gas such as chlorazide, or a readily combustible material and oxygen or an oxygen yielding gas at sub-atmospheric pressure are provided with an opening sealed by a gas-impermeable closure member having, or adapted to have, associated therewith means whereby the filling may be ignited by an externally applied device, the construction being such that no part of the sealing or ignition means projects into the body of the bulb and that the bulb remains substantially closed before and during the ignition of the filling. Fig. 1 shows one form in which a bulb 1 containing aluminium foil 2 and oxygen under reduced pressure is sealed at its neck 3 by a sheet metal diaphragm 4 engaging a beaded edge 5 on its neck. The diaphragm 4 may be of reduced thickness at its centre 6 to facilitate its penetration by a needle-like member having adjacent its point an eye or recess to expose a filament or spark gap connected to an external source of electricity. In another form a central aperture in the diaphragm is covered by a rubber flap allowing the insertion of a tube by which the bulb is exhausted and filled with gas. The rubber flap may subsequently be sealed to the diaphragm by plastic material or by applying a covering of metal or foil. In a further construction the closure member consists of a rubber plug preferably provided on its inner surface with a layer of gasimpermeable material or sealed by an external metal diaphragm. The plug may have a central indentation to facilitate the entry of the igniting device and may carry an exhausting and filling tube. Fig. 6 shows the provision on a bulb such as shown in Fig. 1 of a rubber sleeve 17 which collapses when the igniting needle 12 is forced through the diaphragm 4. Alternatively the needle may be carried by a telescopic casing adapted to clip over the beaded edge of the neck of the bulb or to screw into a sleeve member attached to the neck. Fig. 11 shows a flash-light bulb fitted with a sealing member consisting of a metal diaphragm 19 having sealed at its centre a percussion cap 20 or similar igniting device. The bulb is adapted to be attached to a firing device consisting of a body portion 23 containing a spring operated hammer 24 which is released by means of a lever 26 and reset by operating a fingerpiece 27. Alternatively the percussion cap may be fired by a hammer operated electrically or controlled from a distance. In another construction an ignition mixture is inserted in the closure member and is ignited by applying a lighted match. Specifications 272,394, 324,578, [both in Class 75 (i), Burners &c.], and 357,239 are referred to.