Sliding nozzle flap assembly
Tracks ( 35 ), fastened to static structure of an aircraft engine nozzle, guide sliders ( 32 ) journaled in struts ( 27, 28 ) fastened to a flap ( 23 ) of the nozzle. Each slider and attached journal axle or bolt ( 33 ) is formed of cobalt, and each track slider surface ( 61 ) and journal bushings ( 43, 44 ) are formed of a nickel alloy to reduce wear from rubbing. Track slides ( 40, 41 ) are mounted to the static structure of the nozzle by blind bolts ( 68 ) having a tool recess ( 70 ) at its threaded tip to prevent the bolt ( 68 ) from turning as a nut is secured. Each slider has limited rotation due to a pin ( 102 ), thereon engaging a slot in a tab ( 100 ) of the bushing ( 43 ) to assist in inserting the slider ( 32 ) into the beveled ends of the tracks ( 35, 36 ), when mounting or replacing a flap.
1. Apparatus ( 21 ) for an aircraft engine nozzle, comprising:
an aircraft engine nozzle flap ( 23 ) moveable between first and second positions;
at least one flap positioning arm ( 31 ) for moving the aircraft engine nozzle flap between the first and second positions;
a plurality of guidance struts ( 27 , 28 ), one end of each said plurality of guidance struts attached to the aircraft engine nozzle flap and another end of each said plurality of guidance struts having a bore;
a plurality of guidance tracks ( 35 , 36 ), each one of the plurality of guidance tracks secured to a static structure of the nozzle, each of said plurality of guidance tracks having two, spaced apart longitudinal sliding surfaces ( 61 ); and
a plurality of track sliders ( 32 ), each disposed in a related one of the plurality of guidance tracks, each of the plurality of track sliders rigidly connected to an axle ( 33 ) journaled in the bore of corresponding said plurality of guidance struts, each of the plurality of track sliders having a first axis parallel with an axis of the axle and defining a width of each of the plurality of track sliders, each of the plurality of track sliders having a second axis perpendicular to the first axis and parallel with the longitudinal sliding surfaces of corresponding said plurality of guidance tracks and defining a length of each of the plurality of track sliders, and each of the plurality of track sliders having a third axis perpendicular to the first axis and the second axis and defining a thickness of each of the plurality of track sliders; characterized:
top and bottom surfaces ( 54 , 55 ) defined by the width and the length of each of the plurality of track sliders each having a crown with an apex parallel with the second axis to provide a single line of contact with a corresponding said longitudinal sliding surfaces.
2. Apparatus ( 21 ) according to claim 1 further characterized in that:
each of the crown has a radius of curvature between 3.0 and 4.0 times the height of the slider ( 32 ).
3. Apparatus ( 21 ) according to claim 1 further characterized in that:
the plurality of track sliders ( 32 ) is at least about twice as long as it is thick.
4. Apparatus ( 21 ) according to claim 1 further characterized in that:
the intersections of the top and bottom surfaces of each of the plurality of track sliders ( 32 ) are rounded off.
5. Apparatus ( 21 ) according to claim 1 further characterized in that:
each of the plurality of track sliders ( 32 ) and axle ( 33 ) comprise a nickel alloy and the longitudinal sliding surfaces ( 61 ) of the plurality of guidance tracks which are contacted by each of the plurality of track sliders comprise a cobalt alloy.
6. Apparatus ( 21 ) according to claim 1 further characterized in that:
the bore of each said plurality of guidance struts has at least one bushing ( 43 , 44 ) in contact with the axle ( 33 ) of related each of the plurality of track sliders ( 32 ).
7. Apparatus ( 21 ) according to claim 6 further characterized in that:
the axles ( 33 ) comprise a nickel alloy and bushings ( 43 , 44 ) comprise a cobalt alloy.
8. Apparatus ( 21 ) according to claim 6 further characterized by:
a vibration dampening curved spring washer ( 45 ) disposed on each of the axle ( 33 ) on a side of related said plurality of guidance struts ( 27 , 28 ) adjacent to each of the plurality of track sliders ( 32 ).
9. Apparatus ( 21 ) according to claim 1 further characterized in that:
each of the axle ( 33 ) is threaded and secured to related said plurality of guidance struts ( 27 , 28 ) with a threaded nut ( 52 ).
10. Apparatus ( 21 ) according to claim 1 further characterized by:
the plurality of guidance tracks ( 35 , 36 ) each comprising a frame ( 39 ) secured to the static structure of the nozzle and having track liners ( 40 , 41 ) each comprising a sub-structure ( 60 ) with the longitudinal sliding surfaces ( 61 ) disposed thereon, each sub-structure having a plurality of slot pairs ( 64 , 66 ) for capturing a blind bolt ( 68 ) with a thread-end tool recess ( 70 ) for bolting the track liners to the frame.