Patent GB-410489-A (GB)
Title: Improvements in or connected with flotation gear for aircraft
IPC: B64C35/00
Filed: 1932-11-16
Abstract: 410,489. Storing gases under pressure. DAGNALL, R. F., 17, Stoke Road, and REFFELL, A. H., Ferrymead, Shalford Road, both in Guildford, Surrey. Nov. 16, 1932, No. 32389. [Class 8 (ii).] In flotation equipment for aircraft comprising inflatable bags, gas, e.g. carbon dioxide, is delivered under pressure from a bottle 10 through a passage, including a non-return valve, to the bags automatically, by the completion of an electric circuit which, for example, may include spaced plates so disposed as to be immersed to complete the circuit, when the aircraft descends upon water. In one form, Fig. 3, completion of the circuit causes the explosion of a cartridge 17 which drives a piston 42 upwards in its cylinder, a cam face 53 on the piston thereby causing horizontal movement of a plunger 38 which forces a cutter 19 to break a frangible disc 14 closing the bottle 10, thus releasing the gas to the bags. Manually-operated means for exploding the cartridge in case of emergency comprises a wheel 45 operable by a cord 49 wound around its periphery and keyed to a shaft 55 which rigidly supports a snail cam 56 co-operating with a roller 64 on the plunger 38, so that rotation of the wheel causes the cam to move the plunger axially to break the disc 14. The disc is maintained on its seat by a hollow valve plug 9 screwed into a casting 16 having three bosses 20, 21, 22, Fig. 4, the boss 22 being connected to the bags and communicating with a chamber 26 on the outside of the disc, the boss 20 communicating through a pipe 27 with the bottle side of the disc, and the boss 21 being sealed by a safety nut 35 of H-section which is ruptured to permit the gas in the bottle to escape to atmosphere when its pressure reaches a predetermined limit. The pipe 27 is normally sealed by a frangible disc 28 adapted to be pierced by a cutter 31 secured to a pressure-gauge 29 when the gauge is screwed into the boss 20. A gas-tight joint being formed by a flange 32 on the gauge engaging a rubber washer 33. In a modification, explosion of the cartridge 17, Fig. 2, causes a piston 42 to be driven horizontally to strike a plunger 38 in alignment with the cutter 19 which breaks the disc 14, emergency manually-operated means being provided comprising a wheel 45 secured to the cylinder 41 containing the piston 42, rotation of the wheel by a pull on a peripherally-wound cord 49 causing the cylinder to screw into a casing 27 and act directly on the plunger 38. In a second modification, the bags may be inflated by chemical generation of gas caused by explosion of the cartridge shattering a frangible vessel normally separating two chemical substances which when mixed generate gas in large quantities. An additional electric circuit may be provided including a pair of spaced plates disposed on top of the machine in order to cause inflation of the bags should the aircraft descend upside-down. The arrangement of plates may be duplicated and wired in series to prevent the cartridge being fixed by an accidental short-circuit. The Provisional Specification describes also (a) a construction in which explosion of a cartridge causes a piston to shoot forwards and simultaneously to rotate due to its rod being screw-threaded, the rotary action being utilized to wind up a chain &c., to cause a rotary valve on the gas bottle to open to permit discharge of gas to the floats. (b) manually-operable means for the last construction in which the piston-rod is extended through its cylinder head and has an enlarged fitting on its outer end which may be struck by hand, and (c) the chemical generation of gas by bringing a chemical substance and water into contact by explosion of a cartridge or by manual means.