Patent GB-225884-A (GB)
Title: Method and apparatus for forming letters or symbols in the air
IPC: G09F21/16
Filed: 1924-12-08
Abstract: 225,884. Remey, J. T. Dec. 7, 1923, [Convention date]. Pyrotechnic apparatus and devices.-A method of " sky-typing " consists in the formation of a number of parallel trails of smoke of various lengths which may be emitted from valves spaced along a pipe carried by, an aeroplane or fixed in a breeze, or from timed smoke bombs dropped from an aeroplane or other moving carrier. Thus (1) an aeroplane 7, Fig. 1, may carry a pipe reinforced by a cable to form, a column 5 held down by a streamlined weight 8 and provided with electrically-controlled valves 6 adapted to emit parallel smoke trails 6<1>, which may be broken as at 6<11>, 6<11>. The column 5 is made up of a smokeconveying .rubber hose 14, Fig. 3, reinforced by a stranded cable 10 and accompanied by a multicore electric cable 16, the whole being bound together with a wrapping tape. At intervals short tubes 13 are let into the hose. Each tube carries a valve 6 comprising a housing 12 which has a horizontal bore 21 leading from the tube 13 to the nozzle 22, the bore being open when the core 20 is in its highest position (determined by the key 23 which it carries), but normally closed owing to the depression of the core by the spring 27. The core is raised to permit the emission of smoke by energizing the solenoid 30, current being supplied over one of the wires in the cable 16, the stranded cable 10 serving as a common return. The current to the various valves 6 is controlled by means of perforated tape 75, Fig. 8, which passes between a set of brushes 70 connected to individual wires of the cable 16, and a conducting block 72. The column 5, comprising the hose, stranded cable, and multicore electric cable, is wound in a spiral groove on the surface of a drum 40 located in the aeroplane. The hose 13 and wires 16 terminate in connecting devices 51, 66, which are fixed to the drum and after this has been unwound to the required extent can be connected respectively fo the corresponding parts 52, 68, and so to the smoke supply and to the perforated tape control. The parts 66, 68 constitute plug-and-socket connection for each wire of the cable, the terminals being asymmetrically arranged to ensure the right connections. The parts 51, 62 enable the hose to be coupled to a pipe 53 leading to a two-way valve 54, whereby the hose can be supplied at will either with air under pressure from the upper part of the container 56 (for drying or clearing the hose) or with smoke or smoke-material from its lower part. Air from a drier 57 is supplied to the container 56 by a pump 58. Instead of being suspended from an aeroplane, the smoke-emitting column may be stretched horizontally between two stationary upright supports at right-angles to the wind, or may itself be rigid and upright, or may be anchored below and held up by a small balloon. (2) In the apparatus shown, titanium tetrachloride is preferably used for producing smoke. At night, luminous vapour or sparks may be employed. (3) A number of smoke bombs 80, Fig. 17, may be arranged inside a casing 84 fixed on an aeroplane or on a carrier travelling along a fixed cable or the like. The bombs are suspended from a fuze 82 which releases them in succession, and each contains a fuze 81 having one or more smokeproducing segments.