Power plants – Reaction motor – Interrelated reaction motors
Reexamination Certificate
2001-08-31
2003-09-23
Gartenberg, Ehud (Department: 3746)
Power plants
Reaction motor
Interrelated reaction motors
Reexamination Certificate
active
06622474
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to thrust reversers for jet engines, and more particularly, to anti-deployment mechanisms for thrust reversers.
BACKGROUND OF THE INVENTION
Jet aircraft, such as commercial passenger and military aircraft, utilize thrust reversers on the aircraft's jet engines to reduce the aircraft's speed after landing. One type of thrust reverser used in modem jet aircraft is the cascade type, described in more detail in U.S. Pat. No. 5,448,884. For ease of reference, the description of the cascade type of thrust reverser is substantially reproduced herein.
Referring first to
FIG. 1
, there is shown a conventional aircraft nacelle indicated at
18
which includes a jet engine, such as a Pratt & Whitney PW4000, indicated at
20
(shown in hidden lines) supported by a strut
22
on a wing
24
(only a portion of which is shown). The nacelle
18
includes a nose cowl
26
, a fan cowl
27
, a thrust reverser sleeve
28
, a core cowl
30
and nozzle exhaust
32
. Although some of these components are made up of two mirror image parts split vertically in a clamshell arrangement, each component will be referred to herein as being one piece.
As shown in more detail in
FIGS. 2 and 3
, the thrust reverser system includes an inner duct (fan duct cowl)
36
and outer sleeve
28
. The sleeve
28
translates in an aft direction indicated by an arrow identified by a number
42
in
FIG. 2
, and a forward direction indicated by an arrow identified by a number
44
. When the thrust reverser is deployed, the translating sleeve
28
moves aft from a “stowed” position shown in
FIG. 1
to a “deployed” position shown in FIG.
2
. In this process, cascade vanes
46
(
FIG. 2
) mounted to a thrust reverser support structure are uncovered. Vanes
46
are slanted in a forward direction so that during thrust reverser operation, fan air from the engine is redirected forward through the vanes (indicated by arrows
47
) to aid in decelerating the airplane.
Air driven aft by the engine fan flows along an annular duct
48
(
FIGS. 2 & 3
) formed by the fan duct cowl
36
and core duct cowl
30
. Movement of the sleeve
28
in the aft direction, causes blocker doors
50
to pivot from their stowed positions (shown in
FIG. 3
) to their deployed positions (shown in
FIG. 2
) where the doors are positioned to block rearward movement of the air through duct
48
. In this manner all rearward movement of the engine fan air is redirected forward through the cascade vanes
46
.
Movement of the sleeve
28
is guided along a pair of parallel tracks mounted to the top and bottom of the fan duct cowl
36
in a fore and aft direction. The sleeve
28
is moved between the stowed and deployed positions by means of a number of hydraulic actuators indicated at
54
(FIG.
3
), each having an actuator rod
56
which is connected to the sleeve
28
. More specifically, as shown in
FIGS. 5 and 6
, each actuator
54
is connected to a structural torque box
57
via a gimbal mount
61
thereby allowing the actuator to accommodate lateral variances in sleeve motion. As shown in
FIG. 4
, the actuator rod
56
is located inside the aerodynamic surface of sleeve
28
and is connected to the sleeve
28
by a ball joint
68
. The ball joint
68
is accessible by removing a panel
70
which is bolted to the exterior surface of the sleeve
28
.
In operation, when the thrust reverser is commanded by the pilot to the deployed position, each actuator rod
56
(
FIG. 5
) extends in the aft direction. Conversely, when the thrust reverser is commanded by the pilot to move to the stowed position, each actuator rod
56
retracts in the forward direction. In an exemplary embodiment, the actuator
54
is a thrust reverser actuator currently installed on Boeing
767
airplanes.
As shown in
FIG. 7
, each actuator
54
includes a double acting piston
72
which is extended in the rightward direction (with reference to
FIG. 7
) by hydraulic pressure acting against a face
74
of the piston
72
. Retraction of the piston
72
and the thrust reverser sleeve therewith is accomplished by relieving hydraulic pressure from the piston face
74
, so that hydraulic pressure acting against an opposing face
76
of the piston causes it to move in the leftward direction. The piston
72
is connected to the actuator rod
56
which in turn is connected to the thrust reverser sleeve
28
in the manner described previously.
In the exemplary embodiment, each thrust reverser sleeve is driven by three of the actuators
54
(FIG.
3
). It is important that each actuator
54
extend and retract the sleeve at the same rate to avoid causing the sleeve to bind along the tracks
51
. To accomplish this, operation of each of the three actuators
54
is synchronized by means of an interconnecting synchronizing shaft
80
. The sync shaft
80
(
FIGS. 5 and 6
) is a tube having a stationary outer sleeve and an internal rotating flexible shaft
81
which synchronizes motion of the three actuators. The outer sleeve of the sync shaft
80
is connected to the actuator
54
by a swivel coupling
82
.
In order to explain this synchronizing operation in greater detail, reference is made to the section view of the actuator
54
in FIG.
7
. As shown, the piston
72
is connected via a non-rotating threaded drive nut
84
to a rotating Acme screw
86
. As piston
72
translates the drive nut
84
moves with it. Translating movement of the drive nut
84
along the Acme screw
86
causes the Acme screw to rotate thereby converting translational movement into rotational movement. Synchronizing operation is further accomplished by a worm gear
90
(
FIG. 6
) located inside the actuator housing which engages a spur gear
94
which in turn is mounted to the end of the Acme screw
86
. Furthermore, the internal sync shaft
81
has a splined end tip which is positioned inside a slot (not shown) in the right end of the worm gear
90
.
Referring again to
FIG. 7
, extension and retraction of the thrust reverser sleeve results in rotation of the Acme screw
86
and rotary gear
94
therewith. This causes rotation of the worm gear
90
in a manner that a high torque and low rotational speed input from the Acme screw
86
is converted by the worm gear
90
to a low torque and high rotational speed output to the sync shaft. In the event one of the actuators
54
attempts to move the thrust reverser sleeve at a different rate than the other actuators, their rates are equalized via the common sync shaft and through the respective worm gears, spur gears and Acme screws of the actuators. This results in uniform translation of the thrust reverser sleeve.
In order to allow the thrust reverser sleeve
28
to be moved between the stowed and deployed positions for maintenance purposes while the airplane is on the ground, a manual drive clutch mechanism
96
shown in
FIG. 6
is attached to the left end of the actuator. The manual drive clutch
96
includes a socket (not shown) for receiving a square drive tool (also not shown) in its left end
95
. The manual drive clutch
96
is connected by a female coupling
97
to a threaded male connector
98
at the left end of the actuator. The drive clutch
96
includes a drive shaft
99
(
FIG. 10
) having a square-ended tip which extends in a rightward direction from the clutch and which fits inside an end slot
100
(
FIG. 5
) of the actuator worm gear
90
.
In operation, when the square drive tool is inserted into the manual drive clutch in a rightward direction, the clutch is engaged thereby allowing the square drive tool to drive the worm gear
90
(FIG.
6
), which in turn drives the spur gear
94
, Acme screw
86
to translate the thrust reverser sleeve.
With reference to
FIGS. 8-11
, mechanical lock
104
is connected to the actuator
54
in place of the drive clutch
96
. In turn, the drive clutch
96
is connected to the left end of the mechanical lock
104
. Like elements described previously will be identified in
FIGS. 8 through 11
by like numerals.
The purpose of the mechanical lock
104
is to pre
Hills Gregory S.
Sternberger Joe E.
Gartenberg Ehud
Harness & Dickey & Pierce P.L.C.
The Boeing Company
LandOfFree
Synchronization cross-feed system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Synchronization cross-feed system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Synchronization cross-feed system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3091152