| 摘要 |
An aircraft ejection seat 10 includes a frame 12 and a headrest 18. The vertical position of the seat is adjusted by a pair of motor driven lead screws 22 24 that cooperate with threaded barrel nuts 26 28 attached to the seat frame 12. The upper end of one of these motor driven lead screws 24 drives a slip coupling 30 driving a splined shaft 34. The splined shaft 34 then drives a gearbox 36 mounted to the seat frame 12. The gearbox in turn drives an upper lead screw 40, which acts on an upper barrel nut 42 to move the headrest 18 up and down relative to the seat frame 12. The upper lead screw 40 is driven in the opposite direction from the lower lead screws 22 24. Consequently, as the seat moves up to accommodate a shorter pilot, the headrest moves down to accommodate the shorter torso of the shorter pilot. |
