GB950760A - Improvements relating to escape equipment for airmen - Google Patents

Abstract

950,760. Air cushions; seats. M. L AVIATION CO. Ltd. Oct. 17, 1962 [July 31, 1961], No. 27719/61. Headings A4J and A4M. [Also in Divisions B7 and F2] An aircraft seat has a base supporting an inflatable bag, the upper surface of which defines or is the sole support for that part of the seat which directly supports the airman, the bag being such that when inflated, the rear part of the support portion is raised above the front portion, and the airman is pushed to a half standing position. The seat is shown with the bag 9 collapsed in Fig. 1, and comprises side plates 1, 2 (see also the front view of Fig. 2) from which project back tubes 5 and 6 supporting at their upper ends a head rest assembly 7. A tray 8 forms the base of the seat and contains the collapsed bag, the upper surface of which carries a cushion 10 for the occupant and a shelf 12 for a parachute back pack 13. When wishing to leave the seat against high-g forces, the occupant operates a lever 34 or 35, which firstly releases lap straps 36, (Fig. 1), parachute pack retaining bolts 41, Fig. 2, and collapses the head rest 7, as in Fig. 3, whereupon levers 34 and 35 are baulked. A short reverse motion of lever 34 or 35 frees it for further movement, which inflates the bag as shown in Fig. 3. Straps (not shown) constrain the shape of the inflated bag, and tapes 15 pass through tunnels 14 on the bag, through rings 16, and up to lugs 20, forming guides for rings 18 on the parachute pack shelf 12. Fig. 4 shows mechanism mounted beneath the seat pan, including a shaft 79 having collars 90 connected by cables 110 to the pack retaining bolts 41, Fig. 2, by linkwork 93, 95, 98, to plungers 40 normally engaging plates 39 on the lap straps, and by a cable 131 to a bolt 64 in the headrest assembly, which when withdrawn, frees a stay 60, Fig. 1, permitting a spring 68 to collapse the headrest 50 as in Fig. 3, a plate 65 presenting a smooth surface to the parachute pack. Thus when shaft 79 is rotated, the occupant is released from the seat. Levers 34 and 35 are secured to a shaft 33, Fig. 4, on which is a slidable clutch element 70 which initially secures an arm 76 on sleeve 75 to shaft 33. Arm 76 is connected by link 77 to an arm 78 on shaft 79 so that when the occupant pulls on a lever 34 or 35, shaft 79 rotates to free the occupant. When shaft 79 has rotated sufficiently to do this, a spring biased element 84 in the shaft engages an aperture 89 in side plate 1, to lock the shaft and prevent further movement of lever 34 or 35. Reverse movement of these levers, however, frees arm 76 from shaft 33, and engages clutch element 70 with a collar 32 on the shaft (see Division F2) so that further movement of levers 34 and 35 becomes possible, and pulls a cord 29 to open the valve 27 of a gas bottle 25, to inflate the bag. In a modification, the clutch is omitted, and a lost motion connection between the operating lever and the gas bottle valve ensures that the bag is not inflated until the occupant is released from the seat. In the case of a unit to be fitted to the pan of an existing seat, Fig. 9 (not shown), the normal harness release gear must be operated before the bag is inflated.