GB831472A - Improvements in or relating to ejection seats for aircraft - Google Patents

Abstract

831,472. Ejection seats for aircraft. MARTIN, J., and MARTIN-BAKER AIRCRAFT CO. Ltd. Feb. 20, 1958 [Feb. 22, 1957], No. 6025/57. Class 4. In an ejection seat for aircraft provided with a face protection screen for the airman, means such as flexible cords are provided to restrain the arms of the airman from excessive outward movement during ejection from the aircraft. As shown in Fig. 2, which shows the seat during the initial stage of ejection, the face screen 2 carries a looped handle 6 to the ends of the upper bar of which are secured flexible arm-restraining lines 7, 8 which pass through snubbing boxes 9, attached releasably to the sides 3 of the seat 1, to attachments 11 on the cockpit floor 10. Each line may have a frangible portion 13 or the pin 14 securing each line to its attachment 11 may be frangible or the connection to the floor may be spring loaded to disconnect at a predetermined tension. Each snubbing-box 9, which permits a line to pass through downwardly, but not upwardly, is releasably secured to the seat frame by a spring loaded plunger 26 which is moved axially to release the box by a sear 29 attached to one end of a rod 30 which is moved axially in direction of arrow A, Fig. 4, by a further sear 32 moved in direction B at right angles to A by a rod 35 connected to one arm of a bellcrank 37, the other arm 40 of which is attached through a rod 41, arm 42, shaft 43, arm 44, rod 45 and lever 48 to the plunger 49 of a spring box or a gun 50 which is released or fired automatically in association with the apparatus used to free the airman's harness from the seat. In operation, movement of the face blind 2 to the position shown automatically fires the seat ejection gun which causes the seat to rise from the floor 10 and tension lines 7, 8 in positions where they restrain the airman's arms from outward movement, boxes 9 maintaining such tension in the upper portions of the lines. When a predetermined tension has been reached portions 13 or pins 14 fracture to free the airman and seat completely from the aircraft and, as described, subsequent operation of the harness release mechanism frees the airman from lines 7 and 8 and thereby the face screen 6, to enable him to become separated from the seat. The lines 7 and 8 and boxes 9 may be combined with similar lines and boxes for restraining the airman's legs of the type described in Specification 724,955. Specifications 583,257, 640,520, 652,131, 673,147, 711,234 and 761,507 also are referred to.