GB796264A - Device for indicating the condition or failure of components in an aircraft - Google Patents

Abstract

796,264. Strain indicating-apparatus; recording-apparatus. ORGILL, R. H. Oct. 9, 1956 [Oct. 20, 1955], No. 30701/56. Classes 106 (2) and 106 (4). [Also in Groups XXXIII and XXXVII] Recording - apparatus comprises a series of parallel electrical circuits each independently associated with a component of an aircraft and to each of which components is connected a switch 28 or 29 for completing the corresponding circuit when abnormal characteristics are exhibited by the component and means operated by each circuit for recording the abnormal condition. The switches for completing the recording circuits may be micro-switches 28 or " flexible plate " switches 29 (see Group XXXVII), used alone or in combination and fitted to the component itself or operated by bellows fitted to the component. Leads from the switches 28, 29 fitted to the various components are housed in a cable 25 terminating in a multi-connection plug 24 fitted in a complementary socket 23 mounted on the periphery of a housing 14 for the recording means 20 which are connected by leads 22 to the socket 23 and suitably marked readily to identify the corresponding components. The housing 14 comprises a metal sphere 15 with an outer fireproof flexible covering, packed with alternate layers of flexible asbestos and fibre glass 17 with an outer layer 16 of soft rubber with air pockets to increase buoyancy and covered with a hard rubber skin 16a. The inside of the sphere 15 is packed with sponge rubber 18 which surrounds a ring 19 of insulating material on which the recording means 20 are mounted. The recording means are preferably in the form of low resistance heater cartridges comprising resistance wire embedded in a small block of light coloured heat discolouring material such as paper or a plastic material and provided at each end with metal terminal lugs. The wire may have an S-bend or a coiled portion to concentrate the heating effect. The degree of discoloration of the cartridges indicates the sequence of the failure of a number of components because the circuits are in parallel and less current passes through each as more circuits are closed. A miniature tape recorder may be mounted in the centre of the sphere, which for safety is carried in the tail of the aircraft and may be forcibly ejected in the event of the aircraft crashing with a view to preserving the records. The circuit may also include a fuse 32, ballast resistance 33, master switch 31 for operation manually or by the pitot tube or throttle at a predetermined speed during take off, and a light 36 in the pilot's cabin to give visual warning of abnormal conditions in one or more components.