Patent Description:
A nacelle for an aircraft propulsion system typically includes an inlet, a fan cowl, a thrust reverser, and an exhaust section. The nacelle is typically mounted to a wing or a fuselage of an aircraft via a pylon. The nacelle may provide smooth, aerodynamic surfaces for airflow around and into a gas turbine engine located within the nacelle.

Access doors may be incorporated at different locations on a nacelle to allow for easy and/or quick maintenance access. Pressure relief doors may also be incorporated by the nacelle to help reduce the internal pressures in the event of a failed pressurized ducting, which may be located throughout the interior of the nacelle. Some doors may serve as both an access door and a pressure relief door (i.e., a dual purpose door).

One or more pressure relief latches are typically used to control movement of a pressure relief door from a closed position to an open position. A pressure relief door may be disposed in its open position to reduce an increased pressure within the nacelle, for instance due to a burst event, failure of pressurized ducting, or the like. A pressure relief latch is disposable in each of a latched configuration (e.g., to retain the corresponding pressure relief door in its closed position) and an unlatched configuration (e.g., to allow the corresponding pressure relief door to move to its open position). Pressure relief latches are susceptible to failure in the case of at least a certain temperature increases within the nacelle, for instance due to a fire, engine failure, or the like. If a pressure relief latch fails and allows the corresponding pressure relief door to open during an elevated temperature event within the nacelle, additional air may be directed into the interior of the nacelle to support combustion. One option for addressing this elevated temperature issue is the use of thermal blanket installations. Thermal blanket installations have been utilized to reduce the potential of pressure relief latches being heated by an engine fire or the like to the point where the latch changes to its corresponding unlatched configuration to allow the corresponding pressure relief door to move to its open position.

<CIT> relates to a pressure relief door assembly which is suitable for use in a compartment of an aircraft engine or auxiliary power unit.

A pressure relief door assembly is presented herein. Both the configuration of such a pressure relief door assembly (including at least certain individual components/subassemblies thereof) and the operation/assembly/manufacture of such a pressure relief door assembly are within the scope of this Summary.

According to an aspect of the invention, there is provided a pressure relief door assembly as claimed in claim <NUM>.

According to another aspect of the invention, there is provided a method as claimed in claim <NUM>.

Various embodiments of the invention are claimed in the respective dependent claims thereof.

The subject matter of the present disclosure (invention) is particularly pointed out and distinctly claimed in the concluding portion of the specification. An understanding of the present disclosure may be further facilitated by referring to the following detailed description and claims in connection with the following drawings. Reference to "in accordance with various embodiments" in this Brief Description of the Drawings also applies to the corresponding discussion in the Detailed Description.

A representative aircraft is illustrated in <FIG> and is identified by reference numeral <NUM>. The aircraft <NUM> includes a fuselage <NUM>, a pair of wings <NUM>, a pair of engines <NUM> for each wing <NUM>, a vertical stabilizer <NUM> at an aft end section of the aircraft <NUM>, and a cockpit <NUM> at forward end section of the aircraft <NUM>. Each engine <NUM> may be mounted to the corresponding wing <NUM> in any appropriate manner, including using any appropriate pylon.

A nacelle <NUM> for a propulsion system is illustrated in <FIG>, in accordance with various embodiments. The nacelle <NUM> may include an inlet <NUM>, a fan cowl <NUM>, a thrust reverser <NUM>, and an exhaust system <NUM>. In various embodiments, the nacelle <NUM> may include a pylon <NUM>. The pylon <NUM> may be configured to mount the nacelle <NUM> and an engine surrounded by nacelle <NUM> to an aircraft structure, such as a wing (e.g., a wing <NUM> of the aircraft <NUM> of <FIG>) or aircraft fuselage.

With reference now to <FIG> and <FIG>, an exploded view of a propulsion system <NUM> is illustrated, in accordance with various embodiments. In accordance with various embodiments, the propulsion system <NUM> includes the nacelle <NUM> and a gas turbine engine <NUM>. The gas turbine engine <NUM> may be surrounded by components of the nacelle <NUM>. The nacelle <NUM> may provide smooth, aerodynamic surfaces for airflow around and into the gas turbine engine <NUM>.

In operation, a fan <NUM> of the gas turbine engine <NUM> draws and directs a flow of air into and through the propulsion system <NUM>. Although the gas turbine engine <NUM> is depicted as a turbofan gas turbine engine herein, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines, including turbojet engines, low-bypass turbofans, high bypass turbofans, or any other gas turbine.

Referring to <FIG>, a nacelle <NUM> for a propulsion system is illustrated, in accordance with various embodiments. The nacelle <NUM> may include an inlet <NUM>, a fan cowl <NUM>, a thrust reverser <NUM>, and an exhaust system <NUM>. The inlet <NUM>, fan cowl <NUM>, thrust reverser <NUM>, and exhaust system <NUM> may be positioned around a central longitudinal axis A-A' of the nacelle <NUM>. The nacelle <NUM> provides smooth aerodynamic surfaces for airflow around and into a gas turbine engine surrounded by the nacelle <NUM>. The nacelle <NUM> may be coupled to a pylon <NUM>. The pylon <NUM> may be configured to mount the nacelle <NUM> and the gas turbine engine surrounded by nacelle <NUM> to an aircraft wing (e.g., a wing <NUM> of the aircraft <NUM> of <FIG>) or aircraft body.

The nacelle <NUM> may include one or more doors, such as door 212a, door 214a, and door 216a. For example, the inlet <NUM> may include one or more doors 212a, the fan cowl <NUM> may include one or more doors 214a, and/or the thrust reverser <NUM> may include one or more doors 216a. In various embodiments, the doors 212a, 214a, 216a may translate between an open position, wherein an interior of nacelle <NUM> that is radially inward of the door is exposed, and a closed position, wherein the door contacts and/or forms a sealing interface with the underlying nacelle component (e.g., inlet <NUM>, fan cowl <NUM> or thrust reverser <NUM>). As used herein, "translate" and "translation" may refer to rotational motion, such as pivoting about a hinged joint, or to linear motion. In various embodiments, one or more of the doors 212a, 214a, 216a may be a pressure relief door configured to translate to the open position in response to a pressure differential across the door (i.e., the difference between the pressure in the area on the interior of the door and the pressure in the area on the exterior of the door) exceeding a preselected pressure differential. As used herein, "the area on the interior of a door" refers to a space or area that is radially inward of the door, and "the area on the exterior of a door" refers to a space or area that is radially outward of the door. One or more of the doors 212a, 214a, 216a could be used by the nacelle <NUM> of <FIG>.

A pressure relief door assembly is illustrated in <FIG> and is identified by reference numeral <NUM>. Components of the pressure relief door assembly <NUM> include a pressure relief door <NUM> and a latch <NUM> (the latch <NUM> in turn including a first latch component or latch body <NUM> and a second latch component or latch bolt <NUM>). The pressure relief door <NUM> is disposable in each of a closed position <NUM> (<FIG>) and an open position <NUM> (<FIG>). The latch <NUM> is pressure-actuated and is disposable in each of a latched configuration (so as to retain the pressure relief door <NUM> in its closed position <NUM> of <FIG>) and an unlatched configuration (so as to allow the pressure relief door <NUM> to move to its open position <NUM> of <FIG>). <FIG> also shows the latch <NUM> in its latched configuration, while <FIG> also shows the latch <NUM> in its unlatched configuration. The lock <NUM> is temperature-actuated and is disposable in each of a locked configuration (so as to retain the pressure relief door <NUM> in its closed position <NUM> of <FIG>, and to also retain the latch <NUM> in its latched configuration of <FIG>) and an unlocked configuration (so as to allow the pressure relief door <NUM> to move to its open position <NUM> of <FIG> when the latch <NUM> is in its unlatched configuration).

The pressure relief door <NUM> includes an interior surface <NUM> that interfaces with an interior space <NUM> (e.g., an interior of a nacelle). Both the latch <NUM> and the lock <NUM> are disposed within this interior space <NUM>. A hinge <NUM> of any appropriate type movably interconnects (e.g., pivotally) a door frame <NUM> and the pressure relief door <NUM>. One or more hinges <NUM> may movably interconnect the doorframe <NUM> and the pressure relief door <NUM>, and each such hinge <NUM> may be of any appropriate configuration. The pressure relief door <NUM> pivots about the hinge <NUM> in the direction of the arrow B to change the pressure relief door <NUM> from its closed position <NUM> of <FIG> to its open position <NUM> of <FIG>.

A stop or striker plate <NUM> may protrude from the door frame <NUM> for interfacing with the latch <NUM>. A perimeter of the door frame <NUM> defines an opening <NUM> in which the pressure relief door <NUM> is disposed when in its closed position <NUM> of <FIG>. A space is shown between the outer perimeter of the pressure relief door <NUM> and the inner perimeter of the door frame <NUM> in <FIG> for clarity. An appropriate seal may be disposed between the door frame <NUM> and the pressure relief door <NUM>.

The latch body <NUM> of the latch <NUM> may be formed from any appropriate material or combination of materials, and may be mounted to the pressure relief door <NUM> in any appropriate manner such that the latch body <NUM> is maintained in a fixed position relative to the pressure relief door <NUM>. The latch body <NUM> includes a bore <NUM> in the form of a "blind hole," in that the bore <NUM> extends from a closed end <NUM> to a perimeter of the latch body <NUM>. A detent <NUM> is movably disposed within the bore <NUM> of the latch body <NUM>. A free end of the detent <NUM> that is disposable beyond the perimeter of the latch body <NUM> may include an enlarged head <NUM>. One or more biasing members <NUM> (e.g., a spring <NUM>) is disposed within the bore <NUM>. One part of the spring <NUM> may be maintained in a fixed position relative to the latch body <NUM> (e.g., by the spring <NUM> being seated on the closed end <NUM>), while another part of the spring <NUM> may be maintained in a fixed position relative to the detent <NUM>. In any case, the spring <NUM> biases the detent <NUM> in the direction of the latch bolt <NUM>.

The latch bolt <NUM> is movable relative to each of the pressure relief door <NUM> and the latch body <NUM>, and may be movably interconnected with one or more of the pressure relief door <NUM> and the latch body <NUM> in any appropriate manner. This movable interconnection is shown as a rotational movement in <FIG> in that the latch bolt <NUM> is rotatable about a rotational axis <NUM> in the direction of the arrow A to change the latch <NUM> from its latched configuration of <FIG> to its unlatched configuration of <FIG>. In any case, the latch bolt <NUM> may be characterized as having an outer or perimeter wall <NUM> and a pair of oppositely disposed sidewalls <NUM> (one such sidewall <NUM> being shown in <FIG>, discussed below). A detent recess or pocket <NUM> and a locking recess or pocket <NUM> are disposed on the perimeter wall <NUM> of the latch bolt <NUM>. The latch bolt <NUM> further includes a stop <NUM> that cooperates with the striker plate <NUM> on the door frame <NUM> to change the latch <NUM> from its latched configuration (<FIG>) to its unlatched configuration (<FIG>) such that the pressure relief door <NUM> may be moved from its closed position <NUM> (<FIG>) to its open position <NUM> (<FIG>).

The lock <NUM> is maintained in a fixed position relative to each of the latch body <NUM> and the pressure relief door <NUM>. <FIG> and <FIG> illustrate the lock <NUM> being mounted in any appropriate manner to the latch body <NUM>. The lock <NUM> includes a housing <NUM>, which may include an extension <NUM>. A bimetallic coil <NUM> is disposed within the interior of the housing <NUM>, and includes a first metal layer 378a and a second metal layer 378b that are appropriately secured to one another. One portion of the bimetallic coil <NUM> is appropriately secured to an anchor location <NUM>, with the bimetallic coil <NUM> being "coiled" about this anchor location <NUM>. A locking pin <NUM> is appropriately attached to the bimetallic coil <NUM>, for instance such that the locking pin <NUM> extends from a free end of the bimetallic coil <NUM>. The locking pin <NUM> is movably disposed in a bore <NUM> that extends from within the interior of the housing <NUM> to a perimeter of the housing <NUM>. An outer perimeter of the bore <NUM> may be correspondingly-shaped with an outer perimeter of the locking pin <NUM>. In any case, the locking pin <NUM> may move axially relative to the housing <NUM> in response to expansion or contraction of the bimetallic coil <NUM>.

As previously noted, the latch <NUM> is pressure-actuated. The head <NUM> of the detent <NUM> is disposed in the detent recess <NUM> of the latch bolt <NUM> to retain the pressure relief door <NUM> in the closed position <NUM> of <FIG> (the latched configuration for the latch <NUM>). The latch <NUM> will remain in this latched configuration until a pressure threshold within the interior space <NUM> is satisfied. Satisfaction of the pressure threshold means at least one of: a) that the pressure within the interior space <NUM> at least one of reaches or exceeds a predetermined pressure; or b) an existence of at least a certain pressure differential across the pressure relief door <NUM>. This predetermined pressure is directly proportional to the biasing force exerted by the spring <NUM>, which in turn corresponds with the force that the detent <NUM> exerts on the latch bolt <NUM>.

Prior to the satisfaction of the pressure threshold for the latch <NUM>, the pressure within the interior space <NUM> will exert a force on the pressure release door <NUM> in the direction indicated by the arrows C in <FIG> (and that will attempt to move the pressure relief door <NUM> in a counterclockwise direction about the door hinge <NUM> in the view shown in <FIG> and represented by the arrow B). The force being exerted on the interior surface <NUM> of the pressure relief door <NUM> is opposed by the door frame <NUM> via the engagement between the stop <NUM> of the latch bolt <NUM> and the striker plate <NUM> on the door frame <NUM>. When the pressure threshold for the latch <NUM> is satisfied (e.g., from a burst event), the latch bolt <NUM> will rotate about the rotational axis <NUM> (clockwise in the view shown in <FIG> and represented by the arrow A) and relative to the latch body <NUM> such that the head <NUM> of the detent <NUM> is disposed out of the detent recess <NUM> of the latch bolt <NUM> (the unlatched configuration for the latch <NUM>). With the latch <NUM> now being in this unlatched configuration, the pressure relief door <NUM> may move from the closed position <NUM> of <FIG> to the open position <NUM> of <FIG>.

As previously noted, the lock <NUM> is temperature-actuated. Disposing the lock <NUM> in its locked configuration may be characterized as locking the latch <NUM> in its latched configuration, may be characterized as locking the pressure relief door <NUM> in its closed position <NUM>, or both. The locking pin <NUM> disposed out of the locking recess <NUM> of the latch bolt <NUM> when the lock <NUM> in its unlocked configuration of <FIG>. The lock <NUM> will remain in this unlocked configuration until a temperature threshold within the interior space <NUM> is satisfied. Satisfaction of the temperature threshold means that the temperature within the interior space <NUM> at least one of reaches or exceeds a predetermined temperature (e.g., due to a fire within the interior space <NUM>). When the temperature threshold is satisfied, the bimetallic coil <NUM> changes from the contracted configuration shown in <FIG> to an expanded configuration. This expansion of the bimetallic coil <NUM> produces a corresponding axial movement of the locking pin <NUM> that disposes the locking pin <NUM> within the locking recess <NUM> of the latch bolt <NUM> (e.g., the locking pin <NUM> will protrude beyond the housing <NUM> of the lock <NUM> at this time). With the locking pin <NUM> being disposed within the locking recess <NUM> of the latch bolt <NUM> (the locked configuration for the lock <NUM>), the latch bolt <NUM> is unable to rotate relative to the latch body <NUM> such that the latch <NUM> is locked in its latched configuration of <FIG>. With the latch <NUM> being locked in its latched configuration, the pressure relief door <NUM> is similarly locked in its closed position <NUM> of <FIG>.

The free end of the locking pin <NUM> will be spaced further from a reference location (e.g., from a plane that is perpendicular to the locking pin <NUM> and that extends through the anchor location <NUM>) when the lock <NUM> is in its locked configuration (again where the locking pin <NUM> is disposed in the locking recess <NUM> of the latch bolt <NUM>) compared to its unlocked configuration (where the locking pin <NUM> is disposed out of the locking recess <NUM> of the latch bolt <NUM> - <FIG>). Although the locking pin <NUM> could be entirely disposed within the housing <NUM> when the lock <NUM> is in its unlocked configuration, the locking pin <NUM> could instead protrude beyond the housing <NUM> when the lock <NUM> is also in its unlocked configuration (but by a lesser amount compared to when the lock <NUM> is in its locked configuration).

A fire within the interior space <NUM> may cause a temperature increase within the interior space <NUM> that could satisfy the temperature threshold of the lock <NUM> (such that the lock <NUM> is changed from its unlocked configuration to its locked configuration in accordance with the foregoing). At least a certain temperature increase within the interior space <NUM> may reduce the magnitude of the pressure threshold associated with the latch <NUM> (such that a reduced pressure within the interior space <NUM> would change the latch <NUM> from its latched configuration to its unlatched configuration, to in turn allow the pressure relief door <NUM> to change from its closed position <NUM> (<FIG>) to its open position <NUM> (<FIG>). In the case of a fire, allowing the pressure relief door <NUM> to move to its open position <NUM> would provide additional oxygen to support combustion. As such, the temperature threshold for the lock <NUM> may be selected such that the lock <NUM> changes from its unlocked configuration to its locked configuration with the latch <NUM> remaining in its latched configuration (which in turn maintains the pressure relief door <NUM> in its closed position <NUM>) and which may be beneficial in relation to extinguishing a fire within the interior space <NUM>.

<FIG> illustrate a housing section <NUM> that includes a pressure relief door assembly <NUM> (only schematically illustrated in <FIG>). The housing section <NUM> may be part of a nacelle for an aircraft. The housing section <NUM> may include a plurality of rails <NUM> that are spaced from one another along a longitudinal axis and that are disposed about this longitudinal axis. The rails <NUM> may be attached to an outer wall <NUM> of the housing section <NUM> in any appropriate manner. A support <NUM> may extend between an adjacent pair of rails <NUM> to accommodate mounting of the pressure relief door assembly <NUM> to the housing section <NUM>.

The pressure relief door assembly <NUM> includes a door frame <NUM> (e.g., in accord with the door frame <NUM> of <FIG>), a stop or striker plate <NUM> (e.g., in accord with the striker plate <NUM> of <FIG>), a pressure relief door <NUM> (e.g., in accord with the pressure relief door <NUM> of <FIG>), and a latch <NUM> (e.g., in accord with the latch <NUM> of <FIG>). The door frame <NUM> may be mounted to the support <NUM> of the housing section <NUM> in any appropriate manner (e.g., via one or more fasteners such as bolts).

The latch <NUM> of the pressure relief door assembly <NUM> includes a first latch component or latch body <NUM> (e.g., in accord with the latch body <NUM> of <FIG>) and a second latch component or latch bolt <NUM> (e.g., in accord with the latch bolt <NUM> of <FIG>). The latch bolt <NUM> is rotatable relative to each of the pressure relief door <NUM> and the latch body <NUM> and includes a stop <NUM> (e.g., in accord with the stop <NUM> of <FIG>). The pressure relief door <NUM> is pivotally interconnected with the door frame <NUM> by a pair of door hinges <NUM> (e.g., in accord with the door hinge <NUM> of <FIG>), such that the pressure relief door <NUM> is rotatable about a hinge axis <NUM> for rotation relative to the housing section <NUM> between the closed position of <FIG> (e.g., in accord with <FIG>) and an open position (e.g., in accord with <FIG>). A lanyard <NUM> may extend between the door frame <NUM> and the pressure relief door <NUM> to provide a limit for the open position of the pressure relief door <NUM>.

The discussion of components in <FIG> that have a corresponding component in <FIG> remains applicable unless otherwise noted to the contrary. In addition, the lock <NUM> (<FIG>) may be disposed on/mounted to the latch body <NUM> of <FIG> and <FIG>, in which case the foregoing discussion of the lock <NUM> will also equally apply to the pressure relief door assembly <NUM>.

<FIG> presents a pressure relief door assembly <NUM>' that is a variation of the pressure relief door assembly <NUM> of <FIG> (and thus is identified by a "single prime" designation in <FIG>). Corresponding components between <FIG> and <FIG> are identified by the same reference numeral, and the discussion of these corresponding presented above with regard to <FIG> remains equally applicable to <FIG> unless otherwise noted herein to the contrary. The pressure relief door assembly <NUM>' of <FIG> includes the same general pressure relief door <NUM>, latch <NUM>, and lock <NUM> of the pressure relief door assembly <NUM> of <FIG>. However, the lock <NUM> is disposed in a different position/orientation in <FIG> compared to <FIG>. Instead of the lock <NUM> being mounted on the latch body <NUM> (as in <FIG>), in the case of the pressure relief door assembly <NUM>' of <FIG>, the lock <NUM> is mounted either directly on the pressure relief door <NUM> or on a support (not shown) that in turn is mounted directly on the pressure relief door <NUM>. Moreover, when the lock <NUM> is disposed in its locked configuration, its locking pin <NUM> extends into a locking recess <NUM>' that intersects with a corresponding sidewall <NUM> of the latch bolt <NUM>' for the case of the pressure relief door assembly <NUM>' of <FIG>.

Any feature of any other various aspects addressed in this disclosure that is intended to be limited to a "singular" context or the like will be clearly set forth herein by terms such as "only," "single," "limited to," or the like. Merely introducing a feature in accordance with commonly accepted antecedent basis practice does not limit the corresponding feature to the singular. Moreover, any failure to use phrases such as "at least one" also does not limit the corresponding feature to the singular. Use of the phrase "at least substantially," "at least generally," or the like in relation to a particular feature encompasses the corresponding characteristic and insubstantial variations thereof (e.g., indicating that a surface is at least substantially or at least generally flat encompasses the surface actually being flat and insubstantial variations thereof). Finally, a reference of a feature in conjunction with the phrase "in one embodiment" does not limit the use of the feature to a single embodiment.

The foregoing description has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and skill and knowledge of the relevant art, are within the scope of the present disclosure.

Claim 1:
A pressure relief door assembly (<NUM>; <NUM>), comprising:
a pressure relief door (<NUM>; <NUM>);
a latch (<NUM>; <NUM>) comprising a latch body (<NUM>; <NUM>) and a latch bolt (<NUM>; <NUM>);
a detent (<NUM>) movably interconnected with said latch body (<NUM>; <NUM>);
a lock (<NUM>) comprising a bimetallic coil (<NUM>) and a locking member (<NUM>) interconnected and movable with said bimetallic coil (<NUM>); wherein
the latch bolt (<NUM>; <NUM>) is movable relative to the latch body (<NUM>; <NUM>), wherein said latch bolt (<NUM>; <NUM>) comprises a detent recess (<NUM>) alignable with said detent (<NUM>) and a locking recess (<NUM>) alignable with said locking member (<NUM>) of said lock (<NUM>), wherein said latch (<NUM>; <NUM>) is in a latched configuration when said detent (<NUM>) is disposed in said detent recess (<NUM>) of said latch bolt (<NUM>; <NUM>), and wherein said lock (<NUM>) is disposed in a locked configuration when said locking member (<NUM>) is disposed in said locking recess (<NUM>) of said latch bolt (<NUM>; <NUM>),
wherein:
said locking member (<NUM>) is disposed within said locking recess (<NUM>) of said latch bolt (<NUM>; <NUM>) in response to said pressure relief door assembly (<NUM>; <NUM>) being exposed to a temperature that at least one of reaches or exceeds a predetermined temperature.