GB1280321A - Aircraft ejection seat mechanisms - Google Patents

Abstract

1280321 Aircraft ejection seat apparatus SAAB-SCANIA AB 18 June 1969 [19 June 1968] 30895/69 Heading B7G A seat ejection mechanism has a single operating arm 39, Fig. 2, moved one step at one end by a pilot-actuated link 42 and one step at the other by a cable 24 actuated by cockpit canopy release, each step alone merely taking up lost motion in a pin-and-slot connection 40, 41 between the arm 39 and a firing mechanism catch 38 to that both steps are necessary to move the catch 38 and release detent balls 36 restraining the spring-loaded firing pin 32. If canopy release does not occur, the linkage 42 can be moved a further step sufficient to effect firing pin release. Each arm of the pilot's seat has a projecting handle 9, Fig. 1, which is raised into a position locked by a spring 14 to effect the first step of the linkage 42 by carrying into view a concealed handle 12, which, via a pull lever 16, a splined connection 17, 19 (to allow seat length adjustment) and a helical pin-and-slot connection to a push rod 18, actuates the link 42. Such action also initiates canopy release via a switch 20 which energizes both a gas-cartridge operating the canopy lock 23 and gas-cartridges operating canopy ejectors 22. The lock cartridge is also energizable by a manual plunger 24. Subsequent canopy opening about a pivot 5 actuates the cable 27. Should canopy release not occur, the handle 12 is gripped and raised further to effect the further step of the link 24. An eye 44 prevents undue movement of the cable 27 and a spring loaded catch 46 prevents the arm 39 dropping after canopy release. In a second embodiment (Fig. 5, not shown) breaker pieces (55, 58) are incorporated to ensure a minimum pull on the members 27, 42 before they move the arm 39, the lost-motion connection between which and the catch 38 is a ball-and-groove one (41, 64). A plunger (51) is also incorporated in the catch 38 which effects release of further detent balls (48) normally locking the ejection seat and firing mechanism to the aircraft floor and which is operable manually or by downward movement of the catch 38. A safety lock arm (66) is provided which can be moved to prevent raising of the ram 39. The catch 46 is replaced by a locking pin-and-slot mechanism (45, 62) biased by a plastic slider (63). In other embodiments, the lost-motion connection between the members 38, 39 comprises a sun-planet-annulus epicyclic gearing (Figs. 11 to 13 not shown) and a rotary coupling (Figs. 14 and 15, not shown)