# Patent

## Title
Tandem thrust reverser with multi-point actuation

## Abstract

One embodiment includes a pivot thrust reverser comprising a first tandem pivot door subassembly comprising an inner panel and outer panel connected. A second tandem pivot door subassembly is included comprising an inner panel and outer panel connected. Also included are a first actuator located on a first side of an attachment location to pivot the first tandem pivot door subassembly, a second actuator located on a second side of the attachment location to pivot the second tandem pivot door subassembly, and a third actuator located substantially radially opposite the attachment location to pivot both the first tandem pivot door subassembly and the second tandem pivot door subassembly. The first tandem pivot door is configured to be pivoted from stowed to deployed by the first actuator and the third actuator, and the second tandem pivot door is configured to be pivoted from stowed to deployed by the second actuator and the third actuator.

## Background
CROSS-REFERENCE TO RELATED APPLICATION(S)
The present application claims priority to U.S. Provisional Patent Application Ser. No. 61/768,172, entitled “AIR TANDEM THRUST REVERSER WITH 3 POINT ACTUATION,” filed Feb. 22, 2013, which is hereby incorporated by reference in its entirety. Priority is also claimed to U.S. Provisional Patent Application Ser. Nos. 61/768,154, entitled “ATR PIVOT THRUST REVERSER WITH CONTOURING AROUND CORE,” filed Feb. 22, 2013; 61/768,160, entitled “ATR TANDEM THRUST REVERSER,” filed Feb. 22, 2013; 61/768,166, entitled “ATR TANDEM THRUST REVERSER WITH 4-BAR LINKAGE,” filed Feb. 22, 2013; and 61/768,171, entitled “ATR CONTOURED THRUST REVERSER WITH 3 POINT ACUATION,” filed Feb. 22, 2013. All of these are hereby incorporated by reference in their entirety.


BACKGROUND
The presently disclosed embodiments relate generally to gas turbine engine and/or nacelle assemblies and, more particularly, to thrust reversers used in gas turbine engine and/or nacelle assemblies.
Thrust reversers in gas turbine engine and/or nacelle assemblies are deployed to redirect an aircraft's propulsive air flow, such as in a forward direction rather than aft. This can provide deceleration for the aircraft which, for example, can assist in slowing the aircraft down during landing, and therefore, enable shorter landing distances while reducing stress and wear on an aircraft's brakes. Thrust reversers are particularly useful when a landing surface is icy or wet, and consequently, the aircraft's brakes are less effective.
Commercial gas turbine engines typically include an engine which produces high temperature, high pressure exhaust ejected through a nozzle downstream of the engine, and a bypass duct, which is generally an annular space concentrically located about the engine through which air from the engine fan, known as the fan bypass stream, is passed. Many aircraft applications use high bypass ratio gas turbine engines, where a majority of the aircraft's propulsion is provided by the fan bypass stream, rather than by the exhaust produced from the engine. In such applications, a thrust reverser may be able to operate effectively by redirecting the fan bypass stream alone.
However, providing a thrust reverser to redirect the fan bypass stream presents design challenges. The thrust reverser must be part of an overall aerodynamic design when stowed, yet be capable of effectively deploying at an appropriate angle which captures enough of the fan bypass stream, and redirects this fan bypass stream at the needed angle, to provide deceleration. Additionally, the design can be further complicated by the need to avoid engine and/or nacelle structures, such as a pylon, that can create obstructions for the thrust reverser. To obtain effective thrust reverser designs, complex assemblies with a multitude of parts have generally been used, often requiring translating parts relative to the engine to allow the thrust reverser to deploy at an effective location. These designs also have generally included an obstruction present in the fan bypass stream reversal flow path, such as actuators or linkages. Moreover, these complex designs are less reliable and require greater maintenance costs. Even with these complex designs, significant portions of the fan bypass stream are not redirected, resulting in a less efficient thrust reverser and, as a consequence, the need for longer landing distances and increased wear on the aircraft's brakes.
SUMMARY
One embodiment includes a pivot thrust reverser comprising a first tandem pivot door subassembly comprising an inner panel and an outer panel, with the inner panel and the outer panel are connected. A second tandem pivot door subassembly is included comprising an inner panel and an outer panel. The inner panel and the outer panel are connected. Also included are a first actuator located on a first side of an attachment location to pivot the first tandem pivot door subassembly, a second actuator located on a second side of the attachment location to pivot the second tandem pivot door subassembly, and a third actuator located substantially radially opposite the attachment location to pivot both the first tandem pivot door subassembly and the second tandem pivot door subassembly. The first tandem pivot door is configured to be pivoted from a stowed position to a deployed position by both the first actuator and the third actuator, and wherein the second tandem pivot door is configured to be pivoted from the stowed position to the deployed position by both the second actuator and the third actuator.
Another embodiment includes a method for use in a gas turbine engine. A first tandem pivot door subassembly is provided comprising an inner panel and an outer panel. The inner panel and the outer panel of the first tandem pivot door subassembly are connected. The first tandem pivot door subassembly is pivoted from a stowed position to a deployed position with a first actuator and a third actuator.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a perspective of an embodiment of a gas turbine engine and nacelle assembly with an embodiment of a pivot thrust reverser, shown in a stowed position.
FIG. 1B is a perspective view of the gas turbine engine and nacelle assembly of FIG. 1A with the pivot thrust reverser shown in a deployed position.
FIG. 1C is an aft elevation view of the gas turbine engine and nacelle assembly of FIG. 1B.
FIG. 2A is a perspective view of the pivot thrust reverser in the deployed position showing the inner panels connected to the outer panels by multi-bar linkages.
FIG. 2B is a perspective view of the nacelle assembly with the pivot thrust reverser in the deployed position with three actuators and part of a pylon included. Portions of the nacelle assembly and pylon are omitted to reveal otherwise concealed structures.
FIG. 3A is a plan view of the tandem pivot door subassembly, shown in isolation, in the stowed position.
FIG. 3B is a plan view of the tandem pivot door subassembly, shown in isolation, in the deployed position.
FIG. 4 is an exploded perspective view of an inner panel and outer panel of the tandem pivot door subassembly.
FIG. 5 is a perspective view of part of the nacelle and pylon with another embodiment of a pivot thrust reverser in the deployed position with three actuators. Portions of the nacelle assembly and pylon are omitted to reveal otherwise concealed structures.



While the above-identified drawing figures set forth embodiments of the invention, other embodiments are also contemplated. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features and components not specifically shown in the drawings.
DETAILED DESCRIPTION
Generally, a pivot thrust reverser can be deployed to circumferentially surround (or, synonymously, contour around) a gas turbine engine inner bypass duct wall such that a fan bypass stream is interrupted and reversed with relatively little leakage, while a core stream and a nacelle ventilation stream are unobstructed or substantially unobstructed. When stowed, thrust reverser pivot doors can make up a portion of both a surface of a bypass duct (e.g., an outer duct wall) and an outer surface of a nacelle. The pivot doors can be pivotally deployed from a stowed position to a deployed position, on pivot axises that are positionally fixed relative to the gas turbine engine, by at least three actuators configured so as to avoid interference from engine and/or nacelle structures.
FIGS. 1A, 1B, and 1C show an embodiment of gas turbine engine and nacelle assembly 10. FIG. 1A is a perspective view of assembly 10 with an embodiment of pivot thrust reverser 20 in the stowed position. FIG. 1B shows a perspective view of assembly 10 with pivot thrust reverser 20 in a deployed position. FIG. 1C is an aft elevation view of assembly 10 shown with pivot thrust reverser 20 in the deployed position. Assembly 10 includes nacelle 12, outer surface 14 of nacelle 12, pylon 16, engine 18, nacelle opening 19, pivot thrust reverser 20 with first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24, bypass duct 26, outer surface 28 and inner surface 30 of bypass duct 26, inner panel 31 and outer panel 32 of first tandem pivot door subassembly 22, inner panel 34 and outer panel 35 of second tandem pivot door subassembly 24, upper bifurcation (bi-fi) fairing 40, lower bi-fi fairing 42, linkages 44 and 48 of first tandem pivot door subassembly 22, linkages 46 and 50 of second tandem pivot door subassembly 24, pivot axis 45 of inner panel 31, pivot axis 47 of inner panel 34, pivot axis 49 of outer panel 32, pivot axis 51 of outer panel 35, actuator 52a, fixed pivot connection points 53a and 53b, fixed pivot connection points 54a and 54b, fan bypass stream F1, redirected fan bypass stream F1, nacelle ventilation stream F2, and core stream F3. Certain components of assembly 10, such as a fan of engine 18, have been omitted for simplicity. Nacelle 12 provides an annular housing within which a substantial portion of engine 18 is located. Engine 18 is aligned on axis A of assembly 10 in the illustrated embodiment, and can be connected to pylon 16 at an attachment location. Engine 18 includes a compressor section, a combustor section, and a turbine section (those sections not specifically shown), which in combination produce hot combustion gases that provide operational energy for engine 18. The attachment location in the illustrated embodiments is pylon 16, which provides a means for mounting assembly 10 to an aircraft (not shown). Pivot thrust reverser 20 includes both first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24. As shown here, second tandem pivot door subassembly 24 is spaced approximately 180° from first tandem pivot door subassembly 22 relative to axis A of assembly 10.
When stowed, as shown in FIG. 1A, first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 each form a portion of outer surface 14, such that outer surface 14 is substantially smooth at all points along an exterior of nacelle 12, including interfaces with first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24. Because first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 provide a smooth outer surface 14 of nacelle 12, pivot thrust reverser 20 tends to reduce a risk of undesired aerodynamic concerns.
Inner surface 30 of bypass duct 26 provides an outer surface of a wall covering engine 18. Bypass duct 26 is defined by the annular space within nacelle 12 between inner surface 30 and outer surface 28 of bypass duct 26. Outer surface 28 of bypass duct 26 is formed by a duct wall at the interior of nacelle 12, and first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 when in the stowed position, as shown in FIG. 1A. In this embodiment, inner panel 31 and outer panel 32 of first tandem pivot door subassembly 22 are connected by a multi-bar linkage (further described with regard to FIG. 2A). Inner panel 34 and outer panel 35 of second tandem pivot door subassembly 24 are also connected by another multi-bar linkage (further described with regard to FIG. 2A). In other embodiments, the connection between inner panels 31 and 34 and outer panels 32 and 35 can be made by differing numbers and configurations of linkages, or other types of mechanisms, as desired for particular applications.
Both first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 can pivot on respective pivot axises that are each positionally fixed relative to their respective mounting locations. Thus, first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 can merely pivot into the deployed position, without requiring any translation of portions of nacelle 12, first tandem pivot door subassembly 22, or second tandem pivot door subassembly 24. Both first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 pivot into opening 19 so as to open upstream from an aft end of nacelle 12, such that first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 pivot open inside of nacelle 12, obstructing flow through bypass duct 26.
Fan bypass stream F1 is relatively cold air which enters through the fan at the front end of nacelle 12 and passes through bypass duct 26. When pivot thrust reverser 20 is in the stowed position, fan bypass stream F1 exits from an aft end of nacelle 12 and can provide a majority of the propulsion generated by high bypass gas turbine engine 18. However, when pivot thrust reverser 20 is in the deployed position, as shown in FIGS. 1B and 1C, first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 open inside of nacelle 12 and obstruct at least a portion of the flow of fan bypass stream F1 through bypass duct 26, such that a redirected fan bypass stream F1 no longer exits from the aft end of nacelle 12, but is instead diverted in another direction. Redirected fan bypass stream F1 is redirected by deployed pivot thrust reverser 20 to flow in the forward, or upstream, direction shown in FIGS. 1B and 1C. Importantly, pivot thrust reverser 20 is configured such that there need not be any actuators, linkages, or other obstructions present in F1 flow path when pivot thrust reverser 20 is in the deployed position, which could otherwise obstruct the flow of redirected fan bypass stream F1 in the forward direction, thus reducing the effectiveness of pivot thrust reverser 20. Redirecting fan bypass stream F1 as shown can restrict or prevent fan bypass stream F1 from providing forward propulsion, but can also actively provide deceleration. Yet, nacelle ventilation stream F2 and core stream F3, which flow through the inside of engine 18, can remain substantially unobstructed and continue to flow out downstream of engine 18 when pivot thrust reverser 20 is deployed in substantially the same manner as when pivot thrust reverser 20 is in the stowed position.
In the illustrated embodiment, outer panel 32 is larger than inner panel 31 of first tandem pivot door subassembly 22 and outer panel 35 is larger than inner panel 34 of second tandem pivot door subassembly 24. However, inner panels 31 and 34 and outer panels 32 and 35 can be any combination of sizes, with the relevant configurations adjusted and opening 19 sized accordingly. By using larger outer panels 32 and 35 as shown, outer panels 32 and 35 not only provide structural support to inner panels 31 and 34 respectively, but also take on functional roles. Larger outer panels 32 and 35 provide additional guidance, in addition to the guidance provided by inner panels 31 and 34, for redirecting fan bypass stream F1 in the appropriate forward direction needed to provide deceleration. Consequently, by further guiding redirected fan bypass stream F1 in the forward direction, pivot thrust reverser 20 operates more effectively. Furthermore, larger outer panels 32 and 35 also can function as an air break, and thus provide deceleration in addition to that provided by redirected fan bypass stream F1.
Engine 18 is centered inside nacelle 12, in the illustrated embodiment, and thus is axially aligned with the engine fan at the front end of nacelle 12 (axis A of FIG. 1A). Upper bi-fi fairing 40 and lower bi-fi fairing 42 serve to interconnect nacelle 12 and engine 18, as well as provide additional stiffness for nacelle 12 and space for wires, tubes and other similar components.
In the illustrated embodiment, as best shown in FIG. 1C, linkage 44 provides a hinged connection between inner panel 31 (of first tandem pivot door subassembly 22) and pivot axis 45, with linkage 44 fixed to nacelle 12 at pivot axis 45. In the same manner, linkage 46 provides a hinged connection between inner panel 34 (of second tandem pivot door subassembly 24) and pivot axis 47, with linkage 46 fixed to nacelle 12 at pivot axis 47. Pivot axis 45 of inner panel 31 and pivot axis 47 of inner panel 34 can be positionally fixed relative to assembly 10, nacelle 12, and/or engine 18. Pivot axis 45 is spaced from inner panel 31 and extends from linkage 44 to linkage 48. Similarly, pivot axis 47 is spaced from inner panel 34 and extends from linkage 46 to linkage 50. Linkage 48 provides a connection between inner panel 31 and actuator 52a, while linkage 50 provides a connection between inner panel 34 and actuator 52a. 
Outer panel 32 (of first tandem pivot door subassembly 22) is fixed to nacelle 12 at fixed pivot connection points 53a and 53b, and pivots about pivot axis 49. Points 53a and 53b provide hinge points for outer panel 32 and are located at or near a perimeter of outer panel 32 in nacelle 12, between outer surface 14 of nacelle 12 and outer surface 28 of bypass duct 26, on pivot axis 49. Outer panel 35 (of second tandem pivot door subassembly 24) is fixed to nacelle 12 at fixed pivot connection points 54a and 54b, and pivots about pivot axis 51. Points 54a and 54b provide hinge points for outer panel 35 and are located at or near a perimeter of outer panel 35 in nacelle 12, between outer surface 14 of nacelle 12 and outer surface 28 of bypass duct 26, on pivot axis 51. Pivot axis 49 of outer panel 32 and pivot axis 51 of outer panel 35 can each be positionally fixed relative to assembly 10, nacelle 12, and/or engine 18. Pivot axis 49 extends from point 53a to point 53b. Pivot axis 51 extends from point 54a to point 54b. As shown and discussed throughout, inner panels 31 and 34 can maintain connection with outer panels 32 and 35 by multi-bar linkages 41 and 43. As a result, inner panel 31 and outer panel 32 of first tandem pivot door subassembly 22 can pivot simultaneously about different pivot axises 45 and 49 without translating relative to those axises 45 and 49. Similarly, inner panel 34 and outer panel 35 of second tandem pivot door subassembly 24 can pivot simultaneously about different pivot axises 47 and 51 without translating.
Actuator 52a, along with actuators 52b and 52c (shown in FIGS. 2A and 2B), can pivot both first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 from the stowed position to the deployed position without translation of first tandem pivot door subassembly 22, second tandem pivot door subassembly 24, or any portion of nacelle 12. In the deployed position shown in FIGS. 1B and 1C, first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 circumferentially surround inner surface 30 of bypass duct 26. Inner panel 31 of first tandem pivot door subassembly 22 and inner panel 34 of second tandem pivot door subassembly 24 are each configured to circumferentially surround inner surface 30 of bypass duct 26 such that an at least partially sealing, mating relationship is formed and there is relatively little leakage of fan bypass stream F1 (the only leakage coming from portions where bypass duct 26 is visible). This means that nearly all of fan bypass stream F1 is redirected, resulting in a highly efficient pivot thrust reverser 20. Yet, at the same time entire pivot thrust reverser 20 provides a simplified design requiring minimal parts, and thus increases reliability and reduces maintenance costs.
FIGS. 2A and 2B show perspective views of pivot thrust reverser 20 in the deployed position with three actuators 52a, 52b, and 52c. FIG. 2A shows pivot thrust reverser 20 in isolation with actuators 52a, 52b, and 52c. FIG. 2B shows a top of pivot thrust reverser 20 with a portion of both nacelle 12 and pylon 16 present. Certain assembly 10 components are left out for simplicity. Included, in addition to that shown and described previously, are top link 41a and bottom link 41b of first tandem pivot door subassembly 22, top link 43a and bottom link 43b of second tandem pivot door subassembly 24, actuators 52b and 52c, top overhang 55a and bottom overhang 55b of outer panel 32 of first tandem pivot door subassembly 22, top overhang 56a and bottom overhang 56b of outer panel 35 of second tandem pivot door subassembly 24, multi-bar linkage 41 of first tandem pivot door subassembly 22, multi-bar linkage 43 of second tandem pivot door subassembly 24, surfaces 57a and 57b of outer panel 32 of first tandem pivot door subassembly 22, surfaces 58a and 58b of outer panel 35 of second tandem pivot door subassembly 24, motors 60a, 60b, and 60c, threaded rods 62a, 62b, and 62c, threaded knuckleheads 64a, 64b, and 64c, cutouts 66 and 68, aft edges 70 and 72, and edges 74 and 75.
Multi-bar linkage 41 can include link 41a, link 41b, and linkage 48. Linkage 48 provides a connection between inner panel 31 and actuator 52a, while links 41a and 41b provide a connection between inner panel 31 and outer panel 32. Similarly, multi-bar linkage 43 can include link 43a, link 43b, and linkage 50. Linkage 50 provides a connection between inner panel 31 and actuator 52a, while links 43a and 43b provide a connection between inner panel 34 and outer panel 35. In other embodiments, multi-bar linkages 41 and 43 could include alternate and/or additional connections between actuator 52a, inner panels 31 and 34, and/or outer panels 32 and 35, respectively. Overhangs 55a and 55b of outer panel 32 extend out over surfaces 57a and 57b, providing coverage of links 41a and 41b respectively when pivot thrust reverser 20 is in the stowed position. Overhangs 56a and 56b of outer panel 35 extend out over surfaces 58a and 58b, providing coverage of links 43a and 43b when pivot thrust reverser 20 is in the stowed position. Thus, overhangs 55a, 55b, 56a, and 56b help alleviate aerodynamic concerns of nacelle 12 when pivot thrust reverser 20 is stowed.
Actuators 52a, 52b, and 52c are located between outer surface 28 of bypass duct 26 and outer surface 14 of nacelle 12 (see also FIG. 1C). Outer surface 28 is cut-away in FIG. 2B to show the location of motor 60a of actuator 52a. The configuration of actuators 52a, 52b, and 52c as shown, results in first tandem pivot door subassembly 22 being pivoted from the stowed position to the deployed position by actuators 52a and 52b, while second tandem pivot door subassembly 24 is pivoted by actuators 52a and 52c. 
There may be applications where fan bypass stream F1 has a high enough velocity to create forces on deployed tandem pivot door subassemblies 22 and 24 of a great enough magnitude that actuator 52a alone, without the presence of actuators 52b and/or 52c, would not be able to keep pivot doors 22 and 24 is the proper deployed positions. However, the location of pylon 16 prevents the use of a second actuator opposite (i.e. 180° apart from relative to axis A) actuator 52a. Therefore, actuators 52a, 52b, and 52c are configured to keep tandem pivot door subassemblies 22 and 24 secured in the deployed position, while at the same time avoiding pylon 16 interference. Actuators 52b and 52c are both located near pylon 16, on opposite side of pylon 16. Actuator 52b is located circumferentially between pylon 16 and edge 74 of inner panel 31 of first tandem pivot door subassembly 22 when first tandem pivot door subassembly 22 is in the stowed position. Actuator 52c is located circumferentially between pylon 16 and edge 75 of inner panel 34 of second tandem pivot door subassembly 24 when second tandem pivot door subassembly 24 is in the stowed position. The configuration of the illustrated embodiment also does not require any actuators, linkages, or other obstructions be present in redirected fan bypass stream F1 flow path when pivot thrust reverser 20 is in the deployed position, thus increasing the effectiveness of pivot thrust reverser 20.
Actuators 52a, 52b, and 52c can be, for example, bolt screw linear (i.e. traveling nut) actuators as shown here that include motors 60a, 60b, and 60c, threaded rods 62a, 62b, and 62c, and threaded knuckleheads 64a, 64b, and 64c. However, various other types of actuators can also be used in alternate embodiments to pivot both first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 between the stowed and deployed positions. Motors 60a, 60b, and 60c move threaded knuckleheads 64a, 64b, and 64c down threaded rods 62a, 62b, and 62c towards motors 60a, 60b, and 60c, and in so doing, pivot inner panel 31 on pivot axis 45. Then, due to the connection between inner panel 31 and outer panel 32 by multi-bar linkage 41, outer panel 32 is simultaneously made to pivot on pivot axis 49. At the same time, inner panel 34 is also pivoted on pivot axis 47, and due to the connection between inner panel 34 and outer panel 32 by multi-bar linkage 43, outer panel 35 is simultaneously made to pivot on pivot axis 51. In this manner, first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 are pivoted by actuators 52a, 52b, and 52c about different pivot axises between stowed and deployed positions without translating (relative to assembly 10).
Additionally, inner panel 31 of first tandem pivot door subassembly 22 contains cutout 66 in aft edge 70 and inner panel 34 of second tandem pivot door subassembly 24 contains cutout 68 in aft edge 72. Both cutouts 66 and 68 are located on lower portions of aft edges 70 and 72 respectively. When in the deployed position, as shown here, aft edge 70 of inner panel 31 faces aft edge 72 of inner panel 34. As a result, cutout 66 is aligned to face cutout 68 when tandem pivot door subassemblies 22 and 24 are deployed, forming an opening in pivot thrust reverser 20 to accommodate engine 18. Both cutout 66 and cutout 68 can be arc-shaped, resulting in the opening in pivot thrust reverser 20 being generally circular in shape. However, in alternative embodiments, cutouts 66 and 68 can have various different shapes and be placed at any location on inner panels 31 and 34. Also, when deployed, aft edges 70 and 72 of inner panels 31 and 34 extend longitudinally beyond aft edges of outer panels 32 and 35, such that aft edges 70 and 72 do not have outer panels 32 and 35 located directly behind them.
FIGS. 3A and 3B show a plan view of actuator 52c and second tandem pivot door subassembly 24 in isolation, with second tandem pivot door subassembly 24 pivoted from the stowed to the deployed position. FIG. 3A shows second tandem pivot door subassembly 24 in the stowed position. FIG. 3B shows second tandem pivot door subassembly 24 pivoted to the deployed position. Included, in addition to that shown and described previously, are fixed pivot point 45 and link 80. Fixed pivot point 45 is located on pivot axis 47 (shown in FIG. 1C) and is a pivot connection point about which inner panel 34 rotates. Point 54b, as discussed for FIG. 1C, is located on pivot axis 51, and is a pivot connection point about which outer panel 35 is hinged to nacelle 12 and pivotally rotates. In this embodiment, point 54b is located at or near a perimeter of outer panel 35, and more specifically is at or near an aft end of outer panel 35 which can pivot inside of nacelle 12. Link 80 provides a connection between threaded knucklehead 64c of actuator 52c and linkage 46.
As second tandem pivot door subassembly 24 is pivoted to the deployed position, threaded knucklehead 64c moves down threaded rod 62c. This forces inner panel 34 to pivot about pivot axis 47 on point 45, and in turn, due to the connection between inner panel 34 and outer panel 35 by links 43a and 43b (shown in FIG. 2A), forces outer panel 35 to pivot about pivot axis 51 on point 54b. Thus, pivoting of inner panel 34 results also in pivoting of outer panel 35. Outer panel 35 is held in the position shown in FIG. 3B due to point 54b being fixed to nacelle 12. Therefore, second tandem pivot door subassembly 24 is deployed by pivoting inner panel 34 and outer panel 35 simultaneously about different pivot points. This allows second tandem pivot door subassembly 24 to deploy and avoid interference from nacelle 12 that otherwise would occur due to the location of second tandem pivot door subassembly 24.
FIG. 4 is an exploded perspective view of inner panel 31 and outer panel 32 of first tandem pivot door subassembly 22 of pivot thrust reverser 20. Included, in addition to that shown and described previously, are inward-facing protrusion 67 and side protrusion 69 on outer panel 32. Inner panel 31 is placed on top of outer panel 32, with links 41a and 41b then added to provide the connection between inner panel 31 and outer panel 32. When connected and stowed, aft edge 70 of inner panel 31 extends only up to where side protrusion 69 begins, such that side protrusion 69 at an aft edge of outer panel 32 extends longitudinally beyond aft edge 70. In this embodiment, inward-facing protrusion 67 is of a shape complimentary with cutout 66 in aft edge 70 of inner panel 31, such that inward-facing protrusion 67 protrudes into the location of cutout 66 when inner panel 31 is placed on top of outer panel 32. Also, side protrusion 69 is of a shape complimentary with curved aft edge 70 of inner panel 31, such that side protrusion 69 protrudes up from an interface of aft edge 70 and side protrusion 69. Protrusions 67 and 69 then allow first tandem pivot door subassembly 22 to both provide a substantially smooth outer surface 28 of bypass duct 26 (see FIG. 1C) and a complete outer surface 14 of nacelle 12 when first tandem pivot door subassembly 22 is stowed (see FIG. 1A). Consequently, fan bypass stream F1 experiences relatively little turbulence when passing through bypass duct 26 at the location where outer surface 28 of bypass duct 26 is formed by stowed first tandem pivot door subassembly 22. This allows assembly 10 to produce efficient and effective propulsion even with pivot thrust reverser 20 included in assembly 10.
FIG. 5 shows a perspective view of another embodiment of pivot thrust reverser in the deployed position with three actuators 52a, 52b, and 52c and part of pylon 16 included. Portions of nacelle 12 and pylon 16 are omitted to reveal otherwise concealed structures. Pivot thrust reverser 20 is generally configured the same way as pivot thrust reverser 20, except that inner panels 31 and 34 are connected to outer panels 32 and 35, respectively, with sliding rails 36 and 38 rather than multi-bar linkages 41 and 43 of pivot thrust reverser 20. In the embodiment shown, two sliding rails are used to connect inner panel 34 to outer panel 35, but any number of sliding rails, including a single rail, can be used to make the connection.
Actuators 52a, 52b, and 52c are configured in the same manner as described for FIGS. 2A and 2B. Furthermore, first tandem pivot door subassembly 22 and second tandem pivot door subassembly 24 of pivot thrust reverser 20 are pivoted from the stowed position to the deployed position in same manner described herein for pivot thrust reverser 20.
The present embodiments provide a highly effective thrust reverser for use in a gas turbine engine. This is because configuring inner panels 31 and 34 with cutouts 66 and 68 to circumferentially surround inner surface 30 of bypass duct 26 as shown allows nearly all of fan bypass stream F1 to be redirected in the appropriate direction, while at the same time minimizing the number of components needed to pivot both first and second tandem pivot door subassemblies 22 and 24 from the stowed to the deployed position without interference from nacelle 12. This is turn decreases the weight of thrust reverser 20 while increasing the reliability of thrust reverser 20. Additionally, the design of thrust reverser 20 avoids interference from obstructions and provides a modular assembly which allows for direct mounting of thrust reverser 20 in position.
Discussion of Possible Embodiments
The following are non-exclusive descriptions of possible embodiments of the present invention.
A pivot thrust reverser for use in a gas turbine engine assembly, the pivot thrust reverser comprising a first tandem pivot door subassembly comprising an inner panel and an outer panel, wherein the inner panel and the outer panel are connected; a second tandem pivot door subassembly comprising an inner panel and an outer panel, wherein the inner panel and the outer panel are connected; a first actuator located on a first side of an attachment location to pivot the first tandem pivot door subassembly; a second actuator located on a second side of the attachment location to pivot the second tandem pivot door subassembly; and a third actuator located substantially radially opposite the attachment location to pivot both the first tandem pivot door subassembly and the second tandem pivot door subassembly, wherein the first tandem pivot door is configured to be pivoted from a stowed position to a deployed position by both the first actuator and the third actuator, and wherein the second tandem pivot door is configured to be pivoted from the stowed position to the deployed position by both the second actuator and the third actuator.
The pivot thrust reverser of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, and/or additional components:
The first actuator, the second actuator and the third actuator are all located between a surface of a bypass duct and an outer surface of a nacelle.
The first tandem pivot door and the second tandem pivot door each form both a portion of the surface of the bypass duct and a portion of the outer surface of the nacelle when in the stowed position.
In the deployed position the first tandem pivot door subassembly and the second tandem pivot door subassembly circumferentially surround an inner surface of a bypass duct such that when the pivot thrust reverser is deployed during engine operation a fan bypass stream is redirected while both a core stream and a nacelle ventilation stream flow in the same manner as when the pivot thrust reverser is stowed.
The inner panel and the outer panel of the first tandem pivot door subassembly are configured to rotate simultaneously about different pivot axises, and wherein the inner panel and the outer panel of the second tandem pivot door subassembly are configured to rotate simultaneously about different pivot axises.
The first actuator, the second actuator and the third actuator are configured to pivot both the first tandem pivot door subassembly and the second tandem pivot door subassembly from the stowed position to the deployed position on respective pivot axises that are each positionally fixed relative to the gas turbine engine assembly.
The pivot point of the inner panel of the first tandem pivot door subassembly is located on a linkage operatively connected between an actuator and the inner panel of the first tandem pivot door subassembly, and wherein the pivot point of the outer panel of the first tandem pivot door subassembly is located at or near a perimeter of the outer panel of the first tandem pivot door subassembly.
The second tandem pivot door is spaced approximately 180° from the first tandem pivot door relative to an axis of the gas turbine engine.
The second actuator is circumferentially spaced from the first actuator.
The first tandem pivot door inner panel and outer panel are connected by a first sliding rail, and wherein the second tandem pivot door inner panel and outer panel are connected by a second sliding rail.
The inner panel and the outer panel of the first tandem pivot door subassembly are connected by a third sliding rail.
The first tandem pivot door inner panel and outer panel are connected by a multi-bar linkage.
A method for use in a gas turbine engine assembly, the method comprising providing a first tandem pivot door subassembly comprising an inner panel and an outer panel; connecting the inner panel and the outer panel of the first tandem pivot door subassembly; and pivoting the first tandem pivot door subassembly from a stowed position to a deployed position with a first actuator and a third actuator.
The method of the preceding paragraph can optionally include, additionally and/or alternatively, the following techniques, steps, features and/or configurations:
The inner panel and the outer panel of the first tandem pivot door subassembly are connected to allow the inner panel and the outer panel to rotate simultaneously about different pivot axises.
Providing a second tandem pivot door subassembly spaced from the first tandem pivot door subassembly comprising an inner panel and an outer panel; connecting the inner panel and the outer panel of the second tandem pivot door subassembly; and pivoting the second tandem pivot door subassembly from the stowed position to the deployed position by the third actuator and a second actuator.
The inner panel and the outer panel of the second tandem pivot door subassembly are connected to allow the inner panel and the outer panel to rotate simultaneously about different pivot axises.
Circumferentially surrounding an inner surface of a bypass duct with the first tandem pivot door subassembly and the second tandem pivot door subassembly when the first tandem pivot door subassembly and the second tandem pivot door subassembly are in the deployed position; and redirecting a fan bypass stream during engine operation when the first tandem pivot door subassembly and the second tandem pivot door subassembly are in the deployed position.
The inner panel and the outer panel of the first tandem pivot door subassembly are connected by a first sliding rail, and wherein the inner panel and the outer panel of the second tandem pivot door subassembly are connected by a second sliding rail.
The inner panel and the outer panel of the first tandem pivot door subassembly are connected by a third sliding rail.
The inner panel and the outer panel of the first tandem pivot door subassembly are connected by a multi-bar linkage, and wherein the inner panel and the outer panel of the second tandem pivot door subassembly are connected by a multi-bar linkage.
Any relative terms or terms of degree used herein, such as “substantially”, “essentially”, “generally” and the like, should be interpreted in accordance with and subject to any applicable definitions or limits expressly stated herein. In all instances, any relative terms or terms of degree used herein should be interpreted to broadly encompass any relevant disclosed embodiments as well as such ranges or variations as would be understood by a person of ordinary skill in the art in view of the entirety of the present disclosure, such as to encompass ordinary manufacturing tolerance variations, incidental alignment variations, temporary alignment or shape variations induced by operational conditions, and the like.
Furthermore, terms such as “top,” “upper,” “bottom,” and “lower” are used in a relative sense, and it should be acknowledged that assembly 10 can have many orientations during use, such as when utilized on an aircraft. Such aircraft uses can also include mounting assembly 10 such that thrust reverser 20 can deploy horizontally, vertically, or any angles in between.
While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

## Claims

1. A pivot thrust reverser for use in a gas turbine engine assembly, the pivot thrust reverser comprising:
a first tandem pivot door subassembly comprising an inner panel and an outer panel, wherein the inner panel and the outer panel are connected;
a second tandem pivot door subassembly comprising an inner panel and an outer panel, wherein the inner panel and the outer panel are connected;
a first actuator located on a first side of an attachment location to pivot the first tandem pivot door subassembly;
a second actuator located on a second side of the attachment location to pivot the second tandem pivot door subassembly; and
a third actuator located substantially radially opposite the attachment location to pivot both the first tandem pivot door subassembly and the second tandem pivot door subassembly, wherein the first tandem pivot door is configured to be pivoted from a stowed position to a deployed position by both the first actuator and the third actuator, and wherein the second tandem pivot door is configured to be pivoted from the stowed position to the deployed position by both the second actuator and the third actuator.

2. The pivot thrust reverser of claim 1, wherein the first actuator, the second actuator and the third actuator are all located between a surface of a bypass duct and an outer surface of a nacelle.

3. The pivot thrust reverser of claim 1, wherein the first tandem pivot door and the second tandem pivot door each form both a portion of the surface of the bypass duct and a portion of the outer surface of the nacelle when in the stowed position.

4. The pivot thrust reverser of claim 1, wherein in the deployed position the first tandem pivot door subassembly and the second tandem pivot door subassembly circumferentially surround an inner surface of a bypass duct such that when the pivot thrust reverser is deployed during engine operation a fan bypass stream is redirected while both a core stream and a nacelle ventilation stream flow in the same manner as when the pivot thrust reverser is stowed.

5. The pivot thrust reverser of claim 1, wherein the inner panel and the outer panel of the first tandem pivot door subassembly are configured to rotate simultaneously about different pivot axises, and wherein the inner panel and the outer panel of the second tandem pivot door subassembly are configured to rotate simultaneously about different pivot axises.

6. The pivot thrust reverser of claim 5, wherein the first actuator, the second actuator and the third actuator are configured to pivot both the first tandem pivot door subassembly and the second tandem pivot door subassembly from the stowed position to the deployed position on respective pivot axises that are each positionally fixed relative to the gas turbine engine assembly.

7. The pivot thrust reverser of claim 6, wherein the pivot point of the inner panel of the first tandem pivot door subassembly is located on a linkage operatively connected between an actuator and the inner panel of the first tandem pivot door subassembly, and wherein the pivot point of the outer panel of the first tandem pivot door subassembly is located at or near a perimeter of the outer panel of the first tandem pivot door subassembly.

8. The pivot thrust reverser of claim 1, wherein the second tandem pivot door is spaced approximately 180° from the first tandem pivot door relative to an axis of the gas turbine engine.

9. The pivot thrust reverser of claim 1, wherein the second actuator is circumferentially spaced from the first actuator.

10. The pivot thrust reverser of claim 1, wherein the first tandem pivot door inner panel and outer panel are connected by a first sliding rail, and wherein the second tandem pivot door inner panel and outer panel are connected by a second sliding rail.

11. The pivot thrust reverser of claim 10, wherein the inner panel and the outer panel of the first tandem pivot door subassembly are connected by a third sliding rail.

12. The pivot thrust reverser of claim 1, wherein the first tandem pivot door inner panel and outer panel are connected by a multi-bar linkage.