Hydraulic baulking sync lock

The subject matter of this specification can be embodied in, among other things, a thrust reverser synchronization shaft lock system includes a rotatable shaft comprising at least one radial prong extending radially from the shaft, a hydraulic lock assembly that includes a housing, a piston head having a lock recess, a piston rod extending radially away from the shaft and configured to be urged by the piston head to move the first piston rod end out of engagement with the radial prong to selectably permit rotation of the shaft, and a bias member configured to urge the first piston rod end into engagement with the radial prong, and an electric lock assembly that includes a lock pin and an electric actuator configured to controllably extend and retract the lock pin in and out of engagement with the lock recess.

TECHNICAL FIELD

This instant specification relates to an aircraft thrust reverser actuation locking system.

BACKGROUND

Contemporary aircraft engines may include a thrust reverser actuation system to assist in reducing the aircraft speed during landing. Typical thrust reversers include a movable transcowl that, when in the active position, reverses at least a portion of the airflow passing through the engine.

Accidental or inadvertent activation and deployment of thrust reversers at inappropriate times can be dangerous or deadly. Accidental deployment on the ground while ground crews are performing service on the engine can result in injury or death. Accidental activation during flight can cause a catastrophic loss of airspeed or failure of the airframe. Mechanical malfunctions, such as a loss of hydraulic pressure, can also allow a reverser to move out of the stowed position at an inappropriate time.

To prevent accidental or unintentional thrust reverser deployment, locking mechanisms are used. Before the thrust reverser can be moved from its stowed position, the lock must first be disengaged. Some current reverser lock designs implement rotating jaws to engage a probe. Such designs can be heavy and mechanically complex, which adds weight and maintenance requirements to the aircraft on which they are installed. Some current reverser lock designs implement hydraulically actuated elements that require additional hydraulic control lines that are no longer provided in some newer aircraft designs, and therefore such locks cannot be used with such aircraft.

SUMMARY

In general, this document describes an aircraft thrust reverser actuation locking system.

In an example aspect, a thrust reverser synchronization shaft lock system includes a rotatable shaft comprising at least one radial prong extending radially from the shaft, a hydraulic lock assembly that includes a housing having a tubular inner wall defining a chamber, a piston head configured to contact the tubular inner wall and having a first piston face on a first longitudinal side of the piston head, a second piston face on a second longitudinal side of the piston head opposite the first piston face, and a lock recess, and configured to divide the chamber into a first fluid chamber defined by the tubular inner wall and the first piston face, and a second fluid chamber defined by the tubular inner wall and the second piston face, a piston rod, extending radially away from the shaft from a first piston rod end to a second piston rod end opposite the first piston rod end, and configured to be urged by the piston head to move the first piston rod end out of engagement with the radial prong to selectably permit rotation of the shaft, and a bias member configured to urge the first piston rod end into engagement with the radial prong to selectably prohibit rotation of the shaft, and an electric lock assembly that includes a lock pin, and an electric actuator configured to controllably extend and retract the lock pin in and out of engagement with the lock recess to selectably prohibit and permit movement of the piston rod.

Various embodiments can include some, all, or none of the following features. The tubular inner wall can include a first longitudinal wall portion configured to define the first fluid chamber to have a first lateral cross-sectional area proximal to the first piston rod end, and a second longitudinal wall portion configured to define the second fluid chamber to have a second lateral cross-sectional area that is smaller than the first lateral cross-sectional area distal from the first piston rod end, and the piston head can include a first piston head portion, sized to contact the tubular inner wall such that the first piston face has substantially the first lateral cross-sectional area, and a second piston head portion, sized to contact the tubular inner wall such that the second piston face has substantially the second lateral cross-sectional area. The thrust reverser synchronization shaft lock system can also include a third fluid chamber configured to be in fluid communication with atmospheric gases at ambient pressure or with hydraulic return pressure, and defined by the first longitudinal wall portion and the second piston head portion. The first fluid chamber can be configured to be in fluid communication with a thrust reverser stowage fluid pressure source, and the second fluid chamber can be configured to be in fluid communication with the thrust reverser stowage fluid pressure source. The thrust reverser synchronization shaft lock system can also include a shaft housing disposed about the shaft and defining a shaft fluid chamber configured to be in fluid communication with a thrust reverser deployment fluid source. The thrust reverser synchronization shaft lock system can also include a fluid conduit configured to fluidically connect the first fluid chamber and the second fluid chamber. The fluid conduit can be a tubular conduit defined through the piston rod. The thrust reverser synchronization shaft lock system can also include a pivotable cam configured to engage a cam recess defined in the piston head and pivot to urge longitudinal movement of the piston head and disengage the first piston rod end from the radial prong. The thrust reverser synchronization shaft lock system can also include a drive assembly configured to removably couple torque from a removable rotary power source to the shaft.

In another example aspect, a method of thrust reverser synchronization shaft locking includes removing or equalizing a hydraulic stowage fluid pressure in a first fluid chamber, wherein a hydraulic lock assembly includes a housing, a piston head, a piston rod coupled to the piston head, the first fluid chamber in the housing at a first longitudinal end of the piston head, and a second fluid chamber in the housing at a second longitudinal end of the piston head opposite the first longitudinal end, urging, by a bias member, longitudinal movement of the piston rod in a first direction, the piston rod having a first piston rod end and a second piston rod end opposite the first piston rod end, urging, by longitudinal movement of the piston rod in the first direction, the first piston rod end into engagement with a radial prong extending radially from a rotatable shaft, de-energizing an electric lock assembly, and extending, based on the de-energizing an electric lock assembly, a lock pin into engagement with a recess defined in the piston head.

Various implementations can include some, all, or none of the following features. The method can also include prohibiting, by engagement of the lock pin with the recess, disengagement of the first piston rod end from the radial prong. The method can also include prohibiting, by engagement of the first piston rod end with the radial prong, rotation of the shaft. The method can also include energizing the electric lock assembly, retracting, based on the energizing, the lock pin from engagement with the recess, applying the hydraulic stowage fluid pressure to the first fluid chamber, urging, by the hydraulic stowage fluid pressure in the first fluid chamber, longitudinal movement of the piston head in a second direction opposite the first direction, urging, by longitudinal movement of the piston head in the second direction, longitudinal movement of the piston rod in the second direction, and urging, by longitudinal movement of the piston rod in the second direction, the first piston rod end out of engagement with the radial prong. The method can also include applying the hydraulic stowage fluid pressure to the second fluid chamber, wherein a first piston face of the piston head has a first lateral cross-sectional area, applying a first hydraulic force, based on the first lateral cross-sectional area, to the piston head in the first direction, applying the hydraulic stowage fluid pressure to the first fluid chamber, wherein a second piston face of the piston head has a second lateral cross-sectional area that is larger than the first lateral cross-sectional area, and applying a second hydraulic force, based on the second lateral cross-sectional area, to the piston head in the second direction, wherein the second lateral cross-sectional area is configured such that the second hydraulic force is greater than the first hydraulic force and a bias force of the bias member. Removing or equalizing a hydraulic stowage fluid pressure in a first fluid chamber can include removing the hydraulic stowage fluid pressure from a first piston face on a first longitudinal side of the piston head, the first piston face defining the first fluid chamber in fluid communication with a thrust reverser stowage fluid pressure source of a jet engine thrust reverser system, and removing the hydraulic stowage fluid pressure from a second piston face on a second longitudinal side of the piston head opposite the first piston face, the second piston face defining the second fluid chamber in fluid communication with the thrust reverser stowage fluid pressure source of the jet engine thrust reverser system. The method can also include urging rotation of a pivotable cam engaged with a cam recess defined in the piston rod, urging, based on the rotation, longitudinal movement of the piston rod in a second longitudinal direction opposite the first longitudinal direction, and disengaging, based on the longitudinal movement of the piston rod in the second longitudinal direction, the first piston rod end from the radial prong. The method can also include coupling a removable rotational power source to an input of a drive assembly, urging, by the removable rotational power source, rotation of the input, and urging, by the drive assembly, rotation of the shaft based on the rotation of the input.

The systems and techniques described here may provide one or more of the following advantages. First, the system replaces a conventional two-piece, jaws-type lock mechanism with a much simpler rotary-type design. Second, the system uses a rotary mechanism that is smaller and less complex than the large and heavy moving jaws of jaws-type lock mechanism designs. Third, the system uses a one moving piece mechanism instead of the complex slot and bearing mechanism that is used to swing the jaws of a jaws-type lock. Fourth, the system is lighter and more reliable than jaws-type lock mechanism.

DETAILED DESCRIPTION

This document describes systems and techniques for reversing aircraft turbine engine airflow. A thrust reverser with at least one movable element, which is movable to and from a reversing position, may be used to change the direction of the bypass airflow. In the reversing position, the movable element may be configured to reverse at least a portion of the bypass airflow.

Locking mechanisms engage the thrust reversers to prevent accidental activation or accidental deployment (e.g., during flight, during ground maintenance operations). The paragraphs below describe a mechanism that provides such locking in an assembly that is relatively lighter and less complex than existing designs, and does not use a dedicated hydraulic line for locking, as some existing designs require.

FIG. 1illustrates an example turbofan jet engine assembly10having a turbine engine12, a fan assembly13, and a nacelle14. Portions of the nacelle14have been cut away for clarity. The nacelle14surrounds the turbine engine12and defines an annular airflow path or annular bypass duct16through the jet engine assembly10to define a generally forward-to-aft bypass airflow path, as schematically illustrated by the arrow18. A combustion airflow is schematically illustrated by the arrows19.

A thrust reverser with at least one movable element, which is movable to and from a reversing position, may be used to change the direction of the bypass airflow. In the reversing position, the movable element may be configured to reverse at least a portion of the bypass airflow. There are several methods of obtaining reverse thrust on turbofan jet engine assemblies.FIG. 2schematically illustrates one example of a thrust reverser20that may be used in the turbofan jet engine assembly10. The thrust reverser20includes a movable element22. The movable element22has been illustrated as a cowl portion that is capable of axial motion with respect to the forward portion of the nacelle14. A hydraulic actuator24may be coupled to the movable element22to move the movable element22into and out of the reversing position. In the reversing position, as illustrated, the movable element22limits the annular bypass area between the movable element22and the turbine engine12, it also opens up a portion26between the movable element22and the forward portion of the nacelle14such that the air flow path may be reversed as illustrated by the arrows28. An optional deflector or flap29may be included to aid in directing the airflow path between the movable element22and the forward portion of the nacelle14.

FIG. 3schematically illustrates an alternative example of a thrust reverser30. The thrust reverser30includes a movable element32. The movable element32has been illustrated as a deflector, which may be built into a portion of the nacelle14. A hydraulic actuator34may be coupled to the movable element32to move the movable element32into and out of the reversing position. In the reversing position, shown in phantom and indicated at36, the movable element32turns that air outward and forward to reverse its direction as illustrated by the arrows38. An optional deflector or flap39may be included to aid in directing the airflow path outward.

In both illustrative examples, the thrust reverser changes the direction of the thrust force. Both the thrust reverser20and the thrust reverser30have been described as hydraulically operated systems and a hydraulic actuator has been schematically illustrated. In some embodiments, the thrust reverser20and/or the thrust reverser30can be powered by other fluids (e.g., pneumatic), by electro-mechanical actuators, or by any other appropriate power source or actuator type.

FIG. 4is a schematic view of an example thrust reverser system400. In some embodiments, the thrust reverser system400can include some or all of the example thrust reverser20ofFIG. 2and/or the example thrust reverser30ofFIG. 3. In some embodiments, the example turbofan jet engine assembly10ofFIGS. 1-3can include the example thrust reverser system400.

A moveable transcowl portion410ais affixed to rod ends411of a collection of synchronized actuators430a. A moveable transcowl portion410bis affixed to the rod ends411of a collection of synchronized actuators430b. In the illustrated example, the moveable transcowl portions410aand410bare shown as being flat (e.g., planar) only for ease of viewing. In their intended form, the moveable transcowl portions410aand410bboth have a semi-tubular (e.g., half-cylinder) shape, such that when brought together in a closed configuration the moveable transcowl portions410aand410bform a generally tubular, cylindrical, or conic section that can surround a portion of a turbine engine. For example, the moveable transcowl portions410aand410bcan be the example movable element22or the moveable element32.

The moveable transcowl portion410ais affixed to an aircraft wing, fuselage, or other structural member. The moveable transcowl portion410bis also affixed to an aircraft wing, fuselage, or other structural member.

The synchronized actuators430aand430beach have a proximal end431affixed to the nacelle or other substantially stationary portion of the engine, and a moveable end438(e.g., a piston rod end) that is directly or indirectly coupled to one or both of the moveable transcowl portions410aor410bat their respective rod ends411. A mechanical synchronization system470(e.g., a cable or shaft interlink) interconnects the synchronized actuators430a-430bto transmit lock loads between opposite sides of the thrust reverser system400. The mechanical synchronization system470provides multiple functions. In the illustrated example, the mechanical synchronization system470also provides a fluid conduit that carries pressurized fluid to the synchronized actuators430a-430b(e.g., a cable or shaft that runs through the interior of a fluid conduit, a fluid conduit in which the housing can transmit mechanical torque and also allows fluid to flow through its interior). The synchronized actuators430aare configured to provide actuation primarily to the moveable transcowl portion410a. The synchronized actuators430bare configured to provide actuation primarily to the moveable transcowl portion410b.

The moveable transcowl portions410aand410bare operated by controllably directing pressurized fluid (e.g., hydraulic fluid) from a fluid supply line482, through an isolation valve487, to the synchronized actuators430a-430b, and back to a fluid return line483. Pressurized fluid is provided to a directional control valve488. The directional control valve488is a hydraulic valve that is operable to direct fluid flows to the synchronized actuators430a-430bto actuate the synchronized actuators430a-430band urge movement of the moveable transcowl portions410aand410bbetween a stowed configuration and a deployed configuration. For example, in one configuration of the directional control valve488, pressurized fluid can be directed to flow to the synchronized actuators430a-430bthrough a fluid conduit495and return through a fluid conduit494in order to deploy the moveable transcowl portions410aand410b, and in another configuration of the directional control valve488, pressurized fluid can be directed to flow to the synchronized actuators430a-430bthrough a fluid conduit494and return through a fluid conduit495in order to stow the moveable transcowl portions410aand410b.

In some embodiments, the directional control valve488can be a regenerative type valve. For example, in a regenerative valve, pressure can be applied simultaneously to the deploy line495and to the stow line494in order to deploy the actuators430a-430b.

While the illustrated example has been described in terms of deployment, the thrust reverser system400can be operated in a stow mode. For example, the directional control valve488can be configured to flow pressurized fluid out through the fluid conduit494and receive returned fluid through the fluid conduit495to cause the synchronized actuators430a-430bto retract the moveable transcowl portions410aand410b.

The system400includes a pair of thrust reverser synchronization shaft lock systems440. The thrust reverser synchronization shaft lock systems440are each coupled to ends of the mechanical synchronization system470(e.g., coupled to the rotational motion provided by the synchronization shaft). The thrust reverser synchronization shaft lock systems440are configured to selectively allow intentional rotation and prevent unintentional rotation of the synchronization system470, and thereby selectively allow intentional movement and prevent unintentional movement of the moveable transcowl portions410aand410bbased on fluid pressures provided by the fluid conduits494and495, and an electrical signal provided by a controller441over a collection of electrical signal lines442. The configuration and operation of the thrust reverser synchronization shaft lock systems440will be discussed further in the descriptions ofFIGS. 5A-9.

FIGS. 5A and 5Bare isometric views of an example thrust reverser synchronization shaft lock system500. In some implementations, the thrust reverser synchronization shaft lock system500can be the example thrust reverser synchronization shaft lock system440ofFIG. 4. The thrust reverser synchronization shaft lock system500includes a synchronization system interface510configured to be fluidically coupled to a thrust reverser deployment fluid pressure source (e.g., pressure provided by the example fluid conduit495through the example synchronization system470) and having a synchronization shaft input512configured to be rotatably coupled to a synchronization shaft (e.g., of the example synchronization system470). The thrust reverser synchronization shaft lock system500includes a fluid port520that is configured to be fluidically coupled to a thrust reverser stowage fluid pressure source (e.g., such as fluid pressure provided by the example fluid conduit495). The thrust reverser synchronization shaft lock system500includes an electrical lock assembly530having an electrical input port532configured to electrically connect to an electrical activation signal (e.g., from the controller441over the electrical signal line442). The thrust reverser synchronization shaft lock system500includes a manual unlock assembly540having a manual input542. The thrust reverser synchronization shaft lock system500also includes a manual drive assembly550. These components of the thrust reverser synchronization shaft lock system500will be discussed in more detail in the descriptions ofFIG. 6A-9.

FIGS. 6A-6Care sectional views of the example thrust reverser synchronization shaft lock system500ofFIGS. 5A and 5Bin a locked configuration. The mechanical synchronization system470ofFIG. 4is coupled to the synchronization system interface510through the synchronization shaft input512. When the mechanical synchronization system470is coupled to the synchronization system interface510, a shaft fluid chamber602is defined. The synchronization shaft input512is coupled to a shaft610, and rotation of the mechanical synchronization system470urges rotation of the shaft610. The shaft610includes a radial prong612that extends radially away from the shaft610. In some embodiments, multiple radial prongs such as the radial prong612can extend radially away from the shaft610.

As the shaft rotates, the radial prong612rotates into contact with a rod end622of a piston rod620that is in a locked configuration. Mechanical interference between the first rod end622and the radial prong612prevents further rotation of the shaft610, which in turn prevents further rotation of the mechanical synchronization system470. In the illustrated example, rotation of the mechanical synchronization system470is limited to less than one turn in the locked configuration. The gear ratios of the synchronized actuators430aand430bare configured such that a single turn, or less, of the mechanical synchronization system470will not cause a substantial movement of the moveable transcowl portions410aand410b, substantially locking the moveable transcowl portions410aand410bin place and substantially preventing inadvertent deployment of the thrust reverser400.

The piston rod620is moved into and out of the locked configuration by a hydraulic lock assembly630. The hydraulic lock assembly630includes a housing632having a tubular inner wall634defining a chamber636. A piston head638is configured to contact the tubular inner wall634and has a first piston face640on a first longitudinal side of the piston head638, and a second piston face642on a second longitudinal side of the piston head638opposite the first piston face640.

The piston rod620extends through a cavity621defined through the piston head638, and is configured to move radially within the cavity621. The piston rod620extends radially away from the shaft610from the first piston rod end622to a second piston rod end624opposite the first piston rod end622. The piston rod620includes a stop623that is configured to contact the second piston face642. As the piston head638moves radially away from the shaft610, the second piston face642contacts the stop623and urges radially outward movement of the piston rod620as well. The piston rod620is configured to be urged by contact between the stop623and the piston head638to move the first piston rod end622out of engagement with the radial prong612to selectably permit rotation of the shaft610, as will be discussed in more detail in the descriptions ofFIGS. 7A and 7B.

A bias member660(e.g., a spring) is configured to urge the stop623into engagement with the piston head638, and a bias member662is configured to urge the piston head638in the direction of the shaft610. The actions of the bias members660and662combine to urge the first piston rod end622into the locked configuration where the first piston rod end622can contact and interfere with movement of the radial prong612to selectably prohibit rotation of the shaft610.

Referring toFIGS. 6B and 6C, the electric lock assembly530includes a lock pin672and an electric actuator674that is configured to controllably extend and retract the lock pin672in and out of engagement with a lock recess670defined in the piston head638. The lock recess670is configured to receive a portion of lock pin672. In some embodiments, the electric lock assembly530can be an electric solenoid or any other appropriate form of electrical actuator. The electric lock assembly530is configured to urge the lock pin672toward extension by default, and retract the lock pin672in response to an electrical control signal.

When the lock pin672is urged toward extension, the lock pin672will abut the piston head638until the lock recess670comes into alignment with the lock pin672. Once aligned, the lock pin672will extend into the lock recess670and prohibit longitudinal movement the piston head638, which prevents movement of piston head638when urged by hydraulic pressure which prohibits disengagement of the first piston rod end622from the radial prong612, which prevents rotation of the shaft610.

Referring toFIG. 7B, the lock pin672is shown in a retracted (e.g., unlocked) configuration. When the lock pin672is retracted from the lock recess670, the piston head638is free to move to its unlocked configuration, as will be discussed in more detail in the descriptions ofFIGS. 7A-9. In use, the electric lock assembly530can be controllably activated and deactivated to selectably permit and prohibit movement of the piston head638.

FIGS. 7A and 7Bare sectional views of the example thrust reverser synchronization shaft lock system500ofFIGS. 5A and 5Bin a fluidically unlocked configuration (e.g., unlocked by hydraulic pressure). The piston head638is configured to divide the chamber636into a first fluid chamber650defined by the tubular inner wall634and the first piston face640, and a second fluid chamber652defined by the tubular inner wall634and the second piston face642.

The first fluid chamber650is in fluid communication with the fluid port520(e.g., stow pressure). A tubular fluid conduit654is defined through the length of the piston rod620, and is configured to fluidically connect the first fluid chamber650with the second fluid chamber652. When stow pressure is provided at the fluid port520, both the first fluid chamber650and the second fluid chamber652receive stow pressure. Although the tubular fluid conduit654is defined within the piston rod620in the illustrated example, in some embodiments the fluid conduit can have any appropriate form, such as a dedicated conduit formed through or within the housing632(e.g., a separate tube that connects the chambers650and652) or a conduit defined between the piston rod620and the piston head638.

The hydraulic lock assembly630is configured to urge the first piston rod end622out of the locked position (e.g., engagement with the radial prong612, as shown inFIGS. 6A and 6B) and into an unlocked configuration (e.g., disengagement with the radial prong612, as shown inFIGS. 7A and 7B) when the example thrust reverser synchronization shaft lock system500is subjected to stowage and/or deployment fluid pressures (e.g., during intentional stowage and/or deployment of the thrust reverser400). The tubular inner wall634includes a first longitudinal outer wall portion710that is configured to define the first fluid chamber650to have a first lateral cross-sectional area (represented by arrow712) proximal to the first piston rod end622. The tubular inner wall634also includes a second longitudinal outer wall portion720configured to define the second fluid chamber652to have a second lateral cross-sectional area (represented by arrow722) that is smaller than the first lateral cross-sectional area712distal from the first piston rod end622.

The piston head638includes a first piston head portion724sized to contact the tubular inner wall634such that the first piston face640has substantially the first lateral cross-sectional area712. The piston head638also includes a second piston head portion726, sized to contact the tubular inner wall634such that the second piston face642has substantially the second lateral cross-sectional area722. A variable-volume shaft fluid chamber730is defined by the chamber638between the first longitudinal outer wall portion710and the second piston head portion726. The shaft fluid chamber730is configured to be in fluid communication with atmospheric gases at ambient pressure or with hydraulic return pressure to prevent accumulation of pressure or vacuum within the shaft fluid chamber730as the piston head638moves.

During a deploy operation, the electrical lock assembly530is activated to move the lock pin672to the retracted (e.g., unlocked) configuration shown inFIGS. 7A and 7B. When the lock pin672is retracted from the lock recess670, the piston rod620is able to move away from the locked configuration. Stow pressure is then provided to the first fluid chamber650, and in turn, the second fluid chamber652(e.g., through the tubular fluid conduit654), such that the fluid pressures in the first fluid chamber650and the second fluid chamber652substantially equalize. However, due to the unequal sizes of the cross-sectional areas712and722, the mechanical effects of the equal pressures acting upon the first piston face640and the second piston face642will be unequal. The resulting imbalance in hydraulic force will urge the piston head638to move radially away from the shaft610.

As the piston head638moves away from the shaft610, the second piston face642comes into contact with the stop623and causes the piston rod620to move radially away from the shaft610as well. The radially outward movement of the piston rod620urges the first piston rod end622to retract from interference with the radial prong612, which unlocks the shaft610.

During a deploy operation, the electrical lock assembly530is activated to move the lock pin672to the retracted (e.g., unlocked) configuration shown inFIGS. 7A and 7B. When the lock pin672is retracted from the lock recess670, the piston rod620is able to move away from the locked configuration. Deploy pressure is applied through the synchronization system interface510to the first piston rod end622. The deployment fluid pressure urges movement of the piston head638with a force that is sufficient to overcome the bias force of the bias members662and663and cause the first piston rod end622to move to the retracted configuration. In some embodiments, the stow and deploy pressures can be provided as part of a regenerative hydraulic system, in which fluid pressure can be present on the stow and deploy sides of actuators431(e.g., deploy pressure495and stow pressure494are equal) simultaneously. In such example systems, the stow pressure that is also present during a deploy operation can act upon the piston head638to also urge the piston rod620into the unlocked configuration.

FIG. 8is a sectional view of the example thrust reverser synchronization shaft lock system500ofFIGS. 5A and 5Bin a manually unlocked configuration. The thrust reverser synchronization shaft lock system500includes the manual unlock assembly540having the manual input542(not visible here, but shown inFIGS. 5A, 5B, and 6B). In some examples, the manual unlock assembly540can be used to put the example thrust reverser synchronization shaft lock system500into the unlocked configuration without electrical or hydraulic power (e.g., during ground maintenance of an aircraft).

The manual input542, is coupled to a pivotable cam810. The pivotable cam810includes a prong812that engages with a recess814formed in the piston rod620.

In use, the manual input542is rotated (e.g., by an aircraft mechanic). As the manual input542is rotated (e.g., counterclockwise in the example view) the pivotable cam810and the prong812are rotated as well. Rotation of the prong812, in engagement with the recess814, urges movement of the piston rod620against the force of the bias member660and retracts the first piston rod end622away from interference with the radial prong612. Since the piston rod620is not affixed to the piston head638, the piston rod620can be retracted while the piston head638remains locked by the electrical lock assembly530.

With the first piston rod end622in the unlocked configuration, the shaft610is free to turn. The manual drive assembly550is configured to couple the shaft610to a removable rotary power source of torque (e.g., a box wrench, a powered or manual rotary tool, such as a manual crank handle, a portable drill, or an air wrench) in order to actuate the actuators430a-430b.

The manual drive assembly550includes a coupler850that is coupled to a gear head852by a clutch mechanism854. When not in use, the clutch mechanism854urges the gear head852out of engagement with a collection of gear teeth860extending from the shaft610, which decouples the manual drive assembly from the shaft610. In use, a rotary tool is rotatably mated to the coupler850, and longitudinal force is applied to the coupler850to urge the gear head852into engagement with the gear teeth860. The coupler850can then be rotated to urge rotation of the shaft610.

FIG. 9is a flow diagram of an example process900for locking the example thrust reverser synchronization shaft lock system500ofFIGS. 5A-8.

At910, a hydraulic stowage fluid pressure in a first fluid chamber is removed or equalized (e.g., relative to atmospheric pressure), where a hydraulic lock assembly includes a housing, a piston head, a piston rod coupled to the piston head, the first fluid chamber in the housing at a first longitudinal end of the piston head, and a second fluid chamber in the housing at a second longitudinal end of the piston head opposite the first longitudinal end. For example the example thrust reverser synchronization shaft lock system500can be provided, and stow pressure can be removed or otherwise released from the first fluid chamber650.

At920, a bias member urges longitudinal movement of the piston rod in a first direction, the piston rod having a first piston rod end and a second piston rod end opposite the first piston rod end. For example, the bias member660can urge movement of the piston rod620toward the shaft610.

At930, longitudinal movement of the piston rod in the first direction urges the first piston rod end into engagement with a radial prong extending radially from a rotatable shaft. For example, the piston rod620can move to bring the first piston rod end622into a position that can cause engagement with the radial prong612.

At940, an electric lock assembly is de-energized. For example, the electric actuator674of the electric lock assembly530can be de-energized or otherwise deactivated.

At950, a lock pin is extended into engagement with a recess defined in the piston head, based on the de-energizing an electric lock assembly. For example, when the electric actuator674of the electric lock assembly530is de-energized, the lock pin672is permitted to extend in to the lock recess670.

In some implementations, the process900can also include prohibiting, by engagement of the lock pin with the recess, disengagement of the first piston rod end from the radial prong. For example, when the lock pin672is engaged with the lock recess670, longitudinal movement of the piston rod620is substantially inhibited.

In some implementations, the process900can also include prohibiting, by engagement of the first piston rod end with the radial prong, rotation of the shaft. For example, when the piston rod620is in the locked configuration, the shaft610is prohibited from making more than about one rotation due to mechanical interference between the first piston rod end622and the radial prong612.

In some implementations, the process900can include energizing the electric lock assembly, retracting, based on the energizing, the lock pin from engagement with the recess, applying the hydraulic stowage fluid pressure to the first fluid chamber, urging, by the hydraulic stowage fluid pressure in the first fluid chamber, longitudinal movement of the piston head in a second direction opposite the first direction, urging, by longitudinal movement of the piston head in the second direction, longitudinal movement of the piston rod in the second direction, and urging, by longitudinal movement of the piston rod in the second direction, the first piston rod end out of engagement with the radial prong. For example, the example thrust reverser synchronization shaft lock system500can be reconfigured from the locked configuration shown inFIGS. 6A-6Cto the unlocked configuration shown inFIG. 7A-7Bby energizing the electric lock assembly530to retract the lock pin672from the lock recess670. Then stow pressure can be provided to the hydraulic lock assembly630to retract the piston rod620away from the shaft610and remove the first piston rod end622from engagement with the radial prong612.

In some implementations, the process900can also include applying the hydraulic stowage fluid pressure to the second fluid chamber, where the first piston face has a first lateral cross-sectional area, applying a first hydraulic force, based on the first lateral cross-sectional area, to the piston head in the first direction, applying the hydraulic stowage fluid pressure to the first fluid chamber, wherein the second piston face has a second lateral cross-sectional area that is larger than the first lateral cross-sectional area, and applying a second hydraulic force, based on the second lateral cross-sectional area, to the piston head in the second direction, wherein the second lateral cross-sectional area is configured such that the second hydraulic force is greater than the first hydraulic force and a bias force of the bias member. For example, stow pressure can be applied to the first fluid chamber650and the second fluid chamber652. The difference between the first lateral cross-sectional area712and the second lateral cross-sectional area722causes an imbalance between the hydraulic forces imposed by the first piston head portion724(e.g., a relatively greater force) and the second piston head portion726(e.g. a relatively lesser force).

In some implementations, removing a hydraulic stowage fluid pressure in a first fluid chamber can include removing the hydraulic stowage pressure from a first piston face on a first longitudinal side of the piston head, the first piston face defining the first fluid chamber in fluid communication with a thrust reverser stowage fluid pressure source of a jet engine thrust reverser system, removing the hydraulic stowage fluid pressure from a second piston face on a second longitudinal side of the piston head opposite the first piston face, the second piston face defining the second fluid chamber in fluid communication with the thrust reverser stowage fluid pressure source of the jet engine thrust reverser system. For example, the first fluid chamber650and the second fluid chamber652are fluidically connected, and when stowage pressure against the first piston face640is relieved, the corresponding stowage pressure against the second piston face642is also relieved.

In some implementation, the process900can also include urging rotation of a pivotable cam engaged with a cam recess defined in the piston rod, urging, based on the rotation, longitudinal movement of the piston rod in a second longitudinal direction opposite the first longitudinal direction, and disengaging, based on the longitudinal movement of the piston rod in the second longitudinal direction, the first piston rod end from the radial prong. For example, the manual unlock assembly540can be actuated to manually unlock the thrust reverser synchronization shaft lock system500.

In some implementations, the process900can also include coupling a removable rotational power source to an input of a drive assembly, urging, by the removable rotational power source, rotation of the input, and urging, by the drive assembly, rotation of the shaft based on the rotation of the input. For example, the shaft610can be rotated by coupling a rotary tool to the manual drive assembly550and applying a torque.