Locking Linear Actuator

Abstract

To provide a locking linear actuator, a thrust reverser for an aircraft including a locking linear actuator, and a method for manufacturing a locking linear actuator.SOLUTION: A locking linear actuators 20 include an actuator housing 22 that defines a bore 30 for housing an actuator piston 28 and a lock sleeve 34. A portion of the actuator piston defines a lock aperture, and the lock aperture houses a locking tab 42 that is movable in a radial direction. When the actuator is retracted, the locking tab engages with a step in the surface of the bore to lock the linear actuator, and a distal portion of the lock sleeve extends into a portion of the actuator piston to prevent the locking tab from disengaging from the step in the surface of the bore.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to hydraulic linear actuators. In particular, the present disclosure relates to a locking linear actuator that may be used to deploy thrust reversers on an aircraft. [Background technology]

[0002] Introduction Commercial jet aircraft typically employ thrust reversal or reverse thrust during landing to help slow the aircraft after touch-down. By temporarily redirecting either the jet exhaust or bypass air forward, thrust reversal can provide quicker deceleration, allowing for shorter landing distances and also reducing the wear experienced by the braking system.

[0003] There are three main types of thrust reverser systems: target type thrust reversers, clamshell (or cascade) thrust reversers, and coolant flow thrust reversers. Each type of system operates by redirecting at least a portion of the engine thrust substantially forward. Target type thrust reversers employ hydraulic actuators to deploy a pair of "bucket" type doors that redirect the exhaust flow from the engine forward.

[0004] Current thrust reversers employ hydraulic actuators fitted with locking mechanisms to prevent inadvertent activation and lock indicators so that the actuator lock status may be reliably identified. Unfortunately, current actuators are relatively bulky and include many cooperating parts, resulting in disadvantages in terms of service and maintenance as well as component weight. Additionally, current actuator lock indicator systems in some instances add mechanical friction to the actuator locking mechanism (leading to wear) and necessitating more frequent maintenance and replacement. Summary of the Invention

[0005] The present disclosure provides a locking linear actuator, a thrust reverser employing a locking linear actuator, and a method of manufacturing a locking linear actuator.

[0006] In some embodiments, the present disclosure relates to a locking linear actuator including an actuator housing defining an internal longitudinal bore, an actuator piston disposed within the internal longitudinal bore, the actuator piston configured for slidable movement between a proximal retracted position and a distal extended position, and a locking sleeve disposed within the internal longitudinal bore, the locking sleeve configured for slidable movement between a distal locked position and a proximal unlocked position. Further, when the actuator piston is in the retracted position and the locking sleeve is in the locking position, a distal portion of the locking sleeve extends into a proximal portion of the actuator piston to prevent the actuator piston from leaving the retracted position.

[0007] In some embodiments, the present disclosure relates to a thrust reverser for an aircraft engine, where the thrust reverser includes an aircraft engine nacelle having at least one deployable thrust reverser, and at least one linear actuator within the aircraft engine nacelle coupled to the deployable thrust reverser, whereby deploying the thrust reverser includes extending the at least one linear actuator. The linear actuator includes an actuator housing defining an internal longitudinal bore, an actuator piston disposed within the internal longitudinal bore, the actuator piston configured for slidable movement between a proximal retracted position and a distal extended position, and a locking sleeve disposed within the internal longitudinal bore, the locking sleeve configured for slidable movement between a distal locked position and a proximal unlocked position. Further, when the actuator piston is in the retracted position and the locking sleeve is in the locking position, a distal portion of the locking sleeve extends into a proximal portion of the actuator piston to prevent the actuator piston from leaving the retracted position.

[0008] In some embodiments, the present disclosure relates to a method of manufacturing a locking linear actuator, the method including manufacturing an elongated actuator housing defining an internal longitudinal bore, mounting an actuator piston within the internal longitudinal bore such that the actuator piston is slidably movable between a proximal retracted position and a distal extended position, and mounting a locking sleeve within the internal longitudinal bore proximal to the actuator piston such that the locking sleeve is slidably movable between a distal locked position and a proximal unlocked position, whereby when the actuator piston is in the retracted position and the locking sleeve is in the locking position, a distal portion of the locking sleeve extends into a proximal portion of the actuator piston to prevent the actuator piston from leaving the retracted position.

[0009] The features, functions, and advantages may be realized individually in various embodiments of the present disclosure or may be combined in yet further embodiments, the details of which can be seen in further detail with reference to the following description and drawings. [Brief description of the drawings]

[0010] [Figure 1] A typical jet engine nacelle is depicted with the thrust reverser doors retracted. [Diagram 2] FIG. 2 depicts the jet engine nacelle of FIG. 1 with thrust reverser doors deployed (actuated) to redirect the jet engine exhaust in a direction having a forward component. [Diagram 3] 1 illustrates a schematic depiction of a locking linear actuator coupled to a thrust reverser panel of a thrust reverser system; [Figure 4] 1 illustrates an exemplary locking actuator according to the present disclosure. [Diagram 5] FIG. 5 is a cross-sectional view of a locking linear actuator as shown in FIG. [Figure 6] FIG. 5 is a detailed view of a distal portion of the locking tab, locking aperture, and locking sleeve of the locking linear actuator of FIG. [Figure 7] 5 illustrates hydraulic spaces defined within the locking linear actuator of FIG. 4. [Figure 8] 5 illustrates an initial movement of the locking sleeve upon actuation of the locking linear actuator of FIG. 4; [Figure 9] 6 is a cross-sectional view of FIG. 5 showing the inward translation of the locking tabs of the locking linear actuator of FIG. 4. [Figure 10] 5 illustrates movement of the actuator piston of the locking linear actuator of FIG. 4 when the locking sleeve is in a proximal position. [Figure 11] 5 illustrates the actuator piston of the locking linear actuator of FIG. 4 returned to a proximal position, prior to engagement of the locking sleeve and outward movement of the locking tabs. [Figure 12]5 illustrates the sensors and sensor targets of the locking linear actuator of FIG. 4 when the linear actuator is locked. [Figure 13] 5 illustrates the sensors and sensor targets of the locking linear actuator of FIG. 4 when the linear actuator is unlocked. [Figure 14] 5 illustrates the sensors and sensor targets of the locking linear actuator of FIG. 4 when the linear actuator is unlocked and stowed. [Figure 15] 1 is a flowchart illustrating an exemplary method of manufacturing a locking linear actuator according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Various aspects and examples of the locking linear actuator, thrust reverser system incorporating the locking linear actuator, and method of manufacturing the locking linear actuator are described below and illustrated in the accompanying drawings. Unless otherwise specified, the locking linear actuator, thrust reverser system, and method of manufacturing, their individual steps, and variations may, but need not necessarily, include at least one of the structures, components, functions, and / or variations described, illustrated, and / or incorporated herein. Furthermore, unless specifically excluded, the process steps, structures, components, functions, and / or variations described, illustrated, and / or incorporated herein may be included in other similar devices and methods, including being interchangeable among the disclosed embodiments. The following description of various embodiments is merely exemplary in nature and is not intended to limit the embodiments, their applications, or their uses in any manner. In addition, the advantages offered by the embodiments and examples, as described below, are exemplary in nature, and not all embodiments provide the same advantages or the same degree of advantages.

[0012] This detailed description includes the following immediately following sections: (1) Definitions, (2) Overview, (3) Examples, Components, and Alternatives, (4) Methods of Manufacture, (5) Exemplary Combinations and Further Examples, (6) Advantages, Features, and Benefits, and (7) Conclusion.

[0013] (1) definition Unless otherwise indicated, the following definitions apply herein.

[0014] "Substantially" means that the specific dimensions, ranges, shapes, concepts, or other aspects modified by the term generally match, such that the features or components do not need to match exactly, as appropriate for their intended purpose or function.

[0015] "Comprising," "including," and "having" (and combinations thereof) are used interchangeably as open-ended terms intended to include, but not necessarily be limited to, and not to exclude additional, unrecited elements or method steps.

[0016] "First," "second," and "third," etc. are used to distinguish or identify various members of a group; they are introduced in a particular context and are not intended to indicate an order or numerical limitation or to be fixed identifiers of the members of the group.

[0017] "Coupled" means in a relationship in which the performance of one affects the performance of the other, and includes permanent or releasable connection, or direct or indirect connection through intervening parts, but is not necessarily limited to a physical connection(s).

[0018] (2) Overview The locking linear actuators of the present disclosure may provide improved utility in any application in which a linear hydraulic actuator is utilized, particularly those applications in which it may be advantageous to employ a hydraulic linear actuator having a smaller profile, fewer parts, improved locking mechanisms, and improved lock sensors. Selected representative applications may include manufacturing, construction, agriculture, and civil transportation, particularly the use of linear actuators in civil aircraft. The locking linear actuators of the present disclosure will be described primarily in the context of a thrust reverser system for a civil aircraft, although this should not be considered in any way to limit the utility or applicability of the locking linear actuators of the present disclosure.

[0019] The rear nozzle section of a typical turbofan jet engine nacelle 10 is shown in Figures 1 and 2. The typical jet engine nacelle 10 includes a target-type thrust reverser system 12 having two thrust reverser doors or panels 14, which are shown in a retracted or stowed position in Figure 1 and in an actuated or deployed position in Figure 2. The thrust reverser panels 14 are coupled to the jet engine 16 of the nacelle 10 by one or more locking linear actuators 20, as depicted semi-schematically in Figure 3. The overall performance of the thrust reverser may be improved by incorporating one or more aspects of the locking linear actuator structure and features of the present disclosure.

[0020] (3) Examples, Components, and Alternatives An exemplary locking linear actuator 20 is depicted in a longitudinal vertical cross-section in FIG. 4. The locking linear actuator 20 includes an elongated actuator housing 22 that encloses and secures a linear actuator mechanism. The actuator housing 22 has a distal end 24 and a proximal end 26, where the proximal end 26 is directly or indirectly attached to the jet engine 16 and / or the nacelle 10 of the jet engine. An actuator piston 28 is disposed within an internal longitudinal bore 30 defined by the actuator housing 22 and having a longitudinal bore axis 31. A distal end 32 of the actuator piston 28 may be directly or indirectly coupled to a panel 14 of the thrust reverser system 12. The actuator piston 28 may be configured such that the actuator piston is slidably disposed within the internal longitudinal bore 30 and thus slidably movable between a proximal position corresponding to the thrust reverser panel 14 being retracted or stowed and a distal position corresponding to the thrust reverser panel 14 being extended or deployed.

[0021] A locking sleeve 34 is also disposed within the internal longitudinal bore 30 and is located proximal to the actuator piston 28. Similar to the actuator piston 28, the locking sleeve 34 is configured for sliding translation within the internal longitudinal bore 30 between a distal locking position and a proximal unlocked position.

[0022] Referring to FIG. 4, the actuator piston 28 and the locking sleeve 34 are configured such that when the actuator piston 28 is in the retracted position and the locking sleeve 34 is in the locking position, the distal portion 64 of the locking sleeve extends into the proximal portion 36 of the actuator piston to prevent the actuator piston 28 from leaving the retracted position.

[0023] At least a proximal portion 36 of the actuator piston 28 defines a substantially cylindrical piston sidewall 38. The cylindrical piston sidewall 38 defines at least one locking aperture 40 extending therethrough. A locking tab 42 is movably disposed within the locking aperture 40, and both the locking tab 42 and the locking aperture 40 are sized and shaped to ensure that the locking tab 42 is radially translatable within the locking aperture 40. As shown for the cross-sectional view of the cylindrical piston sidewall 38 in FIG. 5, the locking tab 42 is translatable inwardly and / or outwardly along the radius of a circle defined by the cross-sectional view. In the illustrative embodiment of FIG. 5, the exemplary cylindrical piston sidewall 38 defines three locking apertures 40 spaced 120 degrees apart. As shown, the three corresponding locking tabs 42 are radially outermost.

[0024] The cylindrical piston sidewall 38 is bounded by an inner surface 44 of the interior longitudinal bore 30 within the actuator housing 22. As shown in FIGS. 5 and 6, the inner surface 44 may be configured to define a step 46. In that case, the step 46 is defined as any feature that can positively interact with a corresponding locking tab 42 while in its radially outermost position. As shown for the exemplary locking linear actuator 20, the step 46 may have the form of a circumferential ledge around the entire inner surface 44. The defined step 46 may include a surface perpendicular to the longitudinal bore axis 31 or may be angled relative to the longitudinal bore axis 31 as shown. The step 46 may be continuous or intermittent, provided that the step is located at one or more suitable locations to interact with the locking tab 42. Any shape of the step 46 and locking tab 42 that provides a positive interaction between the actuator piston 28 and the actuator housing 22 may be useful.

[0025] The step 46 may be positioned and shaped such that when the actuator piston 28 is in the proximal and retracted position and the locking tab 42 is positioned sufficiently radially outward, the locking tab 42 extends sufficiently beyond the locking aperture 40 such that the outer edge 48 engages the step 46 on the inner surface 44. When the locking tab 42 engages the step 46 and the actuator piston 28 engages the locking tab 42 through the locking aperture 40, the actuator piston 28 is prevented from translating out of the proximal and retracted position. In this configuration, the actuator piston 28 is locked in place and the linear actuator 20 may be described as being locked as a whole.

[0026] The locking tab 42 and its outer edge 48 may also have any suitable shape and configuration. In the embodiment depicted in FIGS. 5 and 9, the outer edge 48 of the locking tab 42 is curved to strongly interact with the curvature of the step 46. The outer edge may be more or less curved, or may even exhibit no curvature, provided that the locking tab 42 securely engages with the step 46. As shown in more detail in FIG. 6, the locking tab 42 also defines an outer surface 50, an inner surface 52, a distal surface 54, and a proximal surface 56. The locking tab 42 may further include an outer chamfered edge 58, which may be angled complementarily to the angle of the step 46. Additionally, the interaction of the outer chamfered edge 58 with the step 46 helps to place the actuator piston 28 in a fixed configuration when the locking tab 42 is urged outwardly during locking. Similarly, locking tab 42 may include an inner chamfered edge 60 that may be complementarily angled relative to a chamfered edge 62 on locking sleeve 34. The interaction between the locking sleeve's chamfered edge 62 and the locking tab's inner chamfered edge 60 may thereby help seat locking tab 42 against step 46 when the locking sleeve is urged distally.

[0027] As shown in FIGS. 4 and 7 , the locked configuration of the linear actuator 20 may be secured and maintained by properly positioning the locking sleeve 34. A distal portion 64 of the locking sleeve 34 may define a cylindrical sleeve sidewall 66 that is sized and shaped to be inserted or nested and concentric within the cylindrical piston sidewall 38 of the actuator piston 28 when the locking sleeve 34 is in the distal and locked position. In this configuration, the cylindrical sleeve sidewall 66 prevents each locking tab 42 from moving radially inward within its respective locking aperture 40, and thus from disengaging from the step 46 on the inner surface 44 of the internal longitudinal bore 30. The locking sleeve 34 may be maintained in the distal and locked position by any suitable locking sleeve biasing mechanism 68. The locking sleeve biasing mechanism 68 may be, for example, a locking sleeve biasing spring that is disposed within the internal longitudinal bore 30 between the proximal face 70 and the locking sleeve 34 and thus acts by continually urging the locking sleeve 34 distally and thus toward the locking position, thereby keeping the linear actuator 20 locked and preventing the actuator from deploying.

[0028] 6, the actuator housing 22 defines an interior hydraulic space 72 in fluid communication with the interior longitudinal bore 30. The hydraulic space 72 surrounds a synchronizing screw 74 that may regulate the flow of pressurized hydraulic fluid into the hydraulic space 72 from a suitable hydraulic fluid source. A suitable hydraulic fluid source may be, for example, a larger hydraulic system providing power to multiple aircraft systems or a thrust reverser system or a smaller closed circuit hydraulic system dedicated to a single linear actuator.

[0029] 6, the actuator housing 22 may further define one or more channels 76 in fluid communication with both the hydraulic space 72 and a region 78 of the interior longitudinal bore 30 that includes the one or more steps 46. When the linear actuator 20 is locked, the region 78 surrounds the proximal portion 36 of the actuator piston 28, including the outer surfaces 50 of the one or more locking tabs 42. The one or more locking tabs 42 are held in engagement with the steps 46 by the presence of the cylindrical sleeve sidewall 66 of the locking sleeve 34. As long as the locking sleeve 34 maintains the distal locking position, the locking tabs 42 are prevented from moving inwardly and the actuator piston 28 remains in the locked configuration.

[0030] To unlock and deploy the linear actuator 20, the hydraulic pressure in hydraulic space 72 may be increased. As hydraulic pressure in hydraulic space 72 increases, the increased pressure urges the locking sleeve 34 to translate proximally against the force applied by the locking sleeve biasing mechanism 68. When the increased hydraulic pressure becomes greater than the force applied against the locking sleeve 34 by the locking sleeve biasing mechanism 68, the locking sleeve 34 is urged proximally. The distal cylindrical sleeve sidewall 66 of the locking sleeve 34 thus retracts from its nested position within the cylindrical piston sidewall 38 of the cylindrical actuator piston. FIG. 8 illustrates the linear actuator 20 with the locking sleeve 34 urged into the proximal unlocked configuration.

[0031] The pressure in the channel 76 causes the pressure in the hydraulic space 72 to also increase the pressure in the region 78 of the internal longitudinal bore 30. This increased pressure urges the actuator piston 28 distally within the internal longitudinal bore 30, thereby urging the locking tabs 42 to move inwardly as well as directly against the outer surface 50 of each locking tab 42. Once the locking sleeve 34 translates to the unlocked configuration, the locking sleeve 34 no longer impedes the inward movement of the locking tabs 42, and each locking tab 42 moves inwardly until it is stopped. In the exemplary device of FIG. 9, for example, each locking tab 42 may move inwardly until it abuts an internal stop 80 defined by the locking aperture 40. As shown in FIGS. 8 and 9, the locking tab 42 is configured and sized such that once it contacts the internal stop 80, it no longer protrudes from the locking aperture 40 and no longer engages the step 46.

[0032] As shown in FIG. 10, as soon as the locking tab 42 is fully disengaged from the step 46, the increased hydraulic pressure present within the hydraulic space 72 immediately urges the actuator piston 28 in a distal direction, causing the actuator piston 28 to translate to a distal position and deploying the thrust reverser 14 coupled to the actuator piston 28.

[0033] As shown, the locking sleeve 34 is capable of moving between the locked and unlocked positions a smaller distance than is required when the actuator piston 28 translates from a proximal position to a distal position. As a result, under the influence of hydraulic pressure, the locking sleeve 34 can translate to the unlocked configuration very quickly. The movement of the actuator piston 28 is typically slower due to its larger size and mass and longer distance of travel.

[0034] The locking linear actuator 20, and thus its associated thrust reverser panel 14, may be returned to the stowed configuration by reducing the pressure of the hydraulic fluid provided to the hydraulic space 72. As the internal pressure is reduced, the actuator piston 28 is urged back to its original proximal position by the action of an actuator piston biasing mechanism 82. The mechanism 82 may be any suitable biasing mechanism, such as an actuator piston biasing spring, among others. The actuator piston biasing mechanism 82 may be at least somewhat stronger than the locking sleeve biasing mechanism 68 for the locking sleeve 34 to help ensure that the actuator piston 28 returns to the proximal position before the locking sleeve 34 is urged to the distal, locked position. As shown in FIG. 11, the actuator piston 28 has returned to the proximal position, but the locking tab 42 remains within the locking aperture 40. As the locking sleeve 34 is urged to the locked position by the locking sleeve biasing mechanism 68, the chamfered edge 62 of the locking sleeve 34 may interact with the chamfered edge 60 of the locking tab 42. The chamfered edges 60 then urge each locking tab 42 outwardly into engagement with the step 46 .

[0035] The operation of the locking linear actuator 20 may be coordinated with one or more additional locking linear actuators using a synchronizing coupling 84. The synchronizing coupling 84 (FIGS. 4, 7, and 8) may include a flexible-shafted cable 86 (FIGS. 7 and 8) that coordinates the operation of the synchronizing screw 74 (FIGS. 7, 8, 10, and 11) with the synchronizing screws of those additional locking linear actuators to coordinate the operation. The synchronizing coupling 84 may be configured to ensure that the thrust reverser panels move in a substantially synchronized manner when multiple locking linear actuators are operating in a single thrust reverser system. That is, when one thrust reverser panel is moved, any other thrust reversers in the same thrust reverser system are moved an equal distance at substantially the same time. Other mechanical systems for synchronizing the operation of the linear actuators may include any other suitable linkages to coordinate the operation of the coupled linear actuators.

[0036] Operation of the locking linear actuator 20 may be monitored by a sensor 88 disposed adjacent the proximal end 26 of the actuator housing 22. The sensor 88 may then be configured to detect an associated sensor target 90, which may be coupled to a proximal end 92 of the locking sleeve 34. Various combinations of sensors and sensor targets may be useful in the context of the present disclosure. Any suitable sensing technique may be used for the sensor targets and sensors of the locking linear actuator 20, such as capacitive sensing, inductive sensing, optical sensing, magnetic sensing, among others.

[0037] The sensor target 90 may include two sensor activation regions 94 and 96 and a sensor deactivation region 98. As shown in Figures 12 and 13, the sensor 88 may be a type of metal detector. The sensor target 90 may include two metal disks, which when brought close to the sensor 88 (i.e., placed under the center of the sensor) may activate or trigger the sensor. The deactivation region 98 then corresponds to the area between the metal disks, which does not trigger the sensor when placed adjacent to the sensor 88.

[0038] 12, when the linear actuator 20 is in the locked configuration, the sensor 88 is aligned with and adjacent to the deactivation region 98. The sensor 88 is not activated, thereby generating a signal that the locking linear actuator is in the locked configuration. In effect, this configuration may signal to the flight crew that the thrust reverser system coupled to the linear actuator is stowed and locked.

[0039] 13, when the linear actuator 20 is in the unlocked configuration, the locking sleeve 34 is in the proximal unlocked position and the sensor activation region 94 is aligned and adjacent to the sensor 88. The sensor 88 is activated, which generates a signal that the locking linear actuator is in the unlocked configuration and the locking linear actuator is deployed. This configuration may signal the flight crew that a thrust reverser system coupled to the linear actuator has been deployed or is in the process of being deployed.

[0040] Because the locking sleeve 34 is more responsive to changes in hydraulic pressure and can translate more quickly than the actuator piston 28, when the linear actuator 20 is in the process of being retracted or retracted, the locking sleeve 34 can be urged distally beyond the locked configuration until the actuator piston 28 is placed in the locked configuration and urges the locking sleeve 34 into the locked configuration. The configuration of the sensor target 90 is shown in FIG. 14. The sensor activation region 96 is adjacent to the sensor 88, which generates a signal indicating that the locking linear actuator is in the unlocked configuration but is retracted or retracted. Once the locking linear actuator is fully retracted and locked, the sensor 88 again aligns with the sensor deactivation region 98 and signals that the linear actuator is locked and retracted.

[0041] (4) Method of production Manufacturing of the exemplary locking linear actuator 20 is accomplished according to the flowchart 100 of Figure 15. The method of manufacture includes manufacturing an elongated actuator housing, as shown in step 102 of the flowchart 100.

[0042] The elongated actuator housing may be manufactured to define an interior longitudinal bore, an interior hydraulic space in fluid communication with the interior longitudinal bore, and a step on an interior surface of the interior longitudinal bore.

[0043] The method of manufacture further includes installing an actuator piston within the internal longitudinal bore, as shown in step 104 of flowchart 100, such that the actuator piston is slidably movable between a proximal retracted position and a distal extended position.

[0044] The installed actuator piston can be configured such that at least a proximal portion of the actuator piston includes a cylindrical piston sidewall that defines at least one locking aperture.

[0045] The method of manufacture further includes, as shown in step 106 of flowchart 100, installing a locking sleeve within the internal longitudinal bore proximal to the actuator piston such that the locking sleeve is slidably movable between a distal locked position and a proximal unlocked position, whereby when the actuator piston is in a retracted position and the locking sleeve is in the locking position, a distal portion of the locking sleeve extends into a proximal portion of the actuator piston to prevent the actuator piston from leaving the retracted position.

[0046] The method of manufacture may further include installing a locking tab within the at least one locking aperture, as shown at step 108 of flowchart 100, such that the locking tab can translate radially within the locking aperture, such that when the locking tab extends radially beyond an outer surface of the actuator piston, the locking tab engages a step on an inner surface of the internal longitudinal bore to prevent the actuator piston from leaving the retracted position. The locking tab is in fluid communication with the hydraulic space, such that an increase in hydraulic pressure within the hydraulic space urges the locking tab inwardly within the locking aperture. When the actuator piston is in the retracted position and the locking sleeve is in the locking position, a distal portion of the locking sleeve extends into a proximal portion of the actuator piston to prevent the locking tab from moving inwardly and disengaging from the step on the inner surface of the internal longitudinal bore. An increase in hydraulic pressure within the internal hydraulic space will urge the locking sleeve proximally and urge the actuator piston distally.

[0047] When the resulting locking linear actuator is used, increasing the hydraulic pressure in the hydraulic space will cause the locking sleeve to translate proximally, urging the locking tabs to move inwardly within the locking apertures and disengage from the steps, and urging the actuator piston to move from a retracted position to an extended position, urging the actuator piston to move from a retracted position to an extended position.

[0048] The method of manufacture may optionally further include providing an actuator piston biasing mechanism for urging the actuator piston proximally within the internal longitudinal bore and a locking sleeve biasing mechanism configured to urge the locking sleeve distally within the internal longitudinal bore, as shown in step 110 of flowchart 100, such that upon reduction of hydraulic pressure in the hydraulic space, the actuator piston returns to a retracted position and the locking sleeve returns to a locking position such that the locking tab engages the step and locks the linear actuator.

[0049] The method of manufacture may alternatively and optionally further include mounting a sensor adjacent a proximal end of the actuator housing and mounting an associated sensor target on a proximal end of the locking sleeve, as shown in step 112 of flowchart 100, whereby movement of the locking sleeve from one of the locking and unlocked positions to the other results in movement of the sensor target detectable by the sensor to provide an indication of whether the linear actuator is locked or unlocked.

[0050] The method of manufacture may alternatively and optionally further include coupling the hydraulic space to a source of pressurized hydraulic fluid, as shown in step 114 of flowchart 100.

[0051] The method of manufacture may alternatively and optionally further include coupling the actuator housing to an engine of the aircraft, and coupling the actuator piston to a thrust reverser, as shown in step 116 of flowchart 100.

[0052] The method of manufacture may alternatively and optionally further include coupling the thrust reverser to one or more additional linear actuators, as shown in step 118 of flowchart 100, and linking the multiple linear actuators to a synchronization mechanism such that operation of the multiple linear actuators is synchronized.

[0053] (5) Exemplary Combinations and Further Examples This section describes further aspects and features of the disclosed locking linear actuator, thrust reverser employing a locking linear actuator, and method of manufacturing a locking linear actuator. They are presented as a non-limiting series of paragraphs, some or all of which may be designated in alphanumeric order for clarity and efficiency. Each of these paragraphs may be combined in any suitable manner with one or more of the other paragraphs and / or with the disclosure of other parts of this application. Some of the following paragraphs provide, without limitation, some examples of suitable combinations by explicitly referring to and further qualifying other paragraphs.

[0054] A1. 1. A locking linear actuator comprising: an actuator housing defining an internal longitudinal bore; an actuator piston disposed within the internal longitudinal bore, the actuator piston configured for sliding movement between a proximal retracted position and a distal extended position; and a locking sleeve disposed within the internal longitudinal bore, the locking sleeve configured for sliding movement between a distal locked position and a proximal unlocked position, wherein when the actuator piston is in the retracted position and the locking sleeve is in the locking position, a distal portion of the locking sleeve extends into a proximal portion of the actuator piston to prevent the actuator piston from leaving the retracted position. A2. The locking linear actuator of paragraph A1, wherein at least a proximal portion of the actuator piston defines a cylindrical piston sidewall with the cylindrical piston sidewall defining a locking aperture in the cylindrical piston sidewall, the locking tab is disposed within the locking aperture such that the locking tab is radially translatable within the locking aperture, and an inner surface of the internal longitudinal bore defines a step, the step being disposed such that when the actuator piston is in a retracted position and the locking tab within the locking aperture extends beyond the cylindrical piston sidewall of the actuator piston, the locking tab engages the step on the inner surface, thereby preventing the actuator piston from leaving the retracted position. A3. A locking linear actuator as described in paragraph A2, wherein when the actuator piston is in a retracted position and the locking sleeve is in a locking position, a distal portion of the locking sleeve extends into a proximal portion of the actuator piston preventing the locking tabs from moving inwardly and disengaging from a step on an inner surface of the internal longitudinal bore. A4. The locking linear actuator of paragraph A3, wherein the actuator housing further defines a hydraulic space disposed between the actuator piston and the locking sleeve, such that an increase in hydraulic pressure in the hydraulic space urges the locking sleeve in a proximal direction and urges the actuator piston in a distal direction. A5. A locking linear actuator as described in paragraph A4, wherein the hydraulic space is in fluid communication with a portion of the internal longitudinal bore defining the step, such that increasing hydraulic pressure in the hydraulic space urges the locking tab inwardly within the locking aperture, whereby increasing hydraulic pressure in the hydraulic space urges the locking sleeve proximally from the locked position to the unlocked position, thereby enabling the locking tab to move inwardly within the locking aperture and disengage from the step, urged by the increased hydraulic pressure, and enabling the actuator piston to move from the retracted position to the extended position, urged by the increased hydraulic pressure. A6. The locking linear actuator of paragraph A5, further comprising an actuator piston biasing mechanism configured to urge the actuator piston proximally within the internal longitudinal bore so that the actuator piston returns to a retracted position when hydraulic pressure in the hydraulic space decreases. A7. The locking linear actuator of paragraph A5 or A6, further comprising a locking sleeve biasing mechanism configured to urge the locking sleeve distally within the internal longitudinal bore such that the locking sleeve returns to the locking position when hydraulic pressure in the hydraulic space decreases. A8. The locking linear actuator of any one of paragraphs A5 to A7, wherein the linear actuator is further configured to return the actuator piston to the retracted position and the locking sleeve to the locking position, urging the locking tabs radially outwardly to engage the steps, thereby locking the actuator piston in the retracted position. A9. A locking linear actuator described in any one of paragraphs A5 to A8, wherein the hydraulic space disposed between the actuator piston and the locking sleeve further comprises a controllable hydraulic fluid source coupled to a synchronization mechanism coupled to one or more further linear actuators, the synchronization mechanism being configured to coordinate simultaneous operation of the linear actuators. A10. The locking linear actuator of paragraph A9, wherein the controllable hydraulic fluid source includes a synchronizing screw, and the synchronizing mechanism includes a flexible shaft cable extending through an interior of the actuator piston and coupled to the synchronizing screw. A11. The locking linear actuator of any of paragraphs A1-A10, further comprising a sensor disposed adjacent to a proximal end of the actuator housing and configured to detect an associated sensor target coupled to the proximal end of the locking sleeve such that movement of the locking sleeve from the locked position to the unlocked position is detectable by the sensor. A12. The locking linear actuator of paragraph A11, wherein the sensor target includes a deactivation region detectable by the sensor when the locking sleeve is in the locked position, and a first activation region detectable by the sensor when the locking sleeve is in the unlocked position. B1. 1. A thrust reverser for an aircraft engine, comprising: an aircraft engine nacelle including at least one deployable thrust reverser; at least one locking linear actuator in the aircraft engine nacelle coupled to the deployable thrust reverser, such that deploying the thrust reverser comprises extending the at least one linear actuator; the linear actuator including: an actuator housing defining an internal longitudinal bore; an actuator piston disposed in the internal longitudinal bore, the actuator piston configured for slidable movement between a proximal retracted position and a distal extended position; and a locking sleeve disposed in the internal longitudinal bore, the locking sleeve configured for slidable movement between a distal locked position and a proximal unlocked position; B2. 5. The thrust reverser of claim 1, wherein at least a proximal portion of the actuator piston defines a cylindrical piston sidewall with the cylindrical piston sidewall defining a locking aperture in the cylindrical piston sidewall, the locking tab is disposed within the locking aperture such that the locking tab is radially translatable within the locking aperture, an inner surface of the internal longitudinal bore defines a step, the step is disposed such that when the actuator piston is in the retracted position and the locking tab within the locking aperture extends beyond the cylindrical piston sidewall of the actuator piston, the locking tab engages the step on the inner surface thereby preventing the actuator piston from moving away from the retracted position, and a distal portion of the locking sleeve extending into the proximal portion of the actuator piston prevents the locking tab from moving inwardly and disengaging from the step on the inner surface of the internal longitudinal bore when the actuator piston is in the retracted position and the locking sleeve is in the locking position. B3. The thrust reverser of paragraph B2, wherein the actuator housing further defines a hydraulic space disposed between the actuator piston and the locking sleeve, such that an increase in hydraulic pressure in the hydraulic space urges the locking sleeve in a proximal direction and urges the actuator piston in a distal direction, and wherein the hydraulic space is in fluid communication with a portion of the internal longitudinal bore defining the step, such that an increase in hydraulic pressure in the hydraulic space urges the locking tabs inwardly within the locking apertures, whereby increasing hydraulic pressure in the hydraulic space causes the locking sleeve to translate proximally, thus causing a distal portion of the locking sleeve to move from a locking position to an unlocked position, allowing the locking tabs to move inwardly within the locking apertures, urged by the increased hydraulic pressure, and allowing the actuator piston to move from a retracted position to an extended position, urged by the increased hydraulic pressure. B4. The thrust reverser of paragraph B3, further comprising an actuator piston biasing spring configured to urge the actuator piston proximally within the internal longitudinal bore so that the actuator piston returns to a retracted position when hydraulic pressure in the hydraulic space decreases, and a locking sleeve biasing spring configured to urge the locking sleeve distally within the internal longitudinal bore so that the locking sleeve returns to a locking position when hydraulic pressure in the hydraulic space decreases. B5. The thrust reverser of paragraph B3 or B4, further comprising a plurality of linear actuators, each linear actuator comprising a hydraulic fluid source coupled to a synchronization mechanism coupled to each other linear actuator, whereby the synchronization mechanism is configured to coordinate simultaneous operation of the plurality of linear actuators when the thrust reverser is deployed. B6. The thrust reverser described in paragraph B5, wherein the synchronization mechanism of each linear actuator includes a flexible shaft cable extending through an interior portion of each actuator piston and coupled to a synchronization screw that controls hydraulic pressure within the linear actuator. B7. The thrust reverser of any of paragraphs B1 to B6, further comprising a sensor disposed adjacent to a proximal end of the actuator housing and configured to detect an associated sensor target coupled to the proximal end of the locking sleeve such that movement of the locking sleeve from the locking position to the unlocked position is detectable by the sensor. C1. 1. A method of manufacturing a locking linear actuator, the method comprising: manufacturing an elongated actuator housing defining an internal longitudinal bore; mounting an actuator piston within the internal longitudinal bore such that the actuator piston is slidably movable between a proximal retracted position and a distal extended position; and mounting a locking sleeve within the internal longitudinal bore proximal to the actuator piston such that the locking sleeve is slidably movable between a distal locked position and a proximal unlocked position, whereby when the actuator piston is in the retracted position and the locking sleeve is in the locking position, a distal portion of the locking sleeve extends into a proximal portion of the actuator piston to prevent the actuator piston from leaving the retracted position. C2. The actuator housing further defines an interior hydraulic space in fluid communication with the interior longitudinal bore and the step on the inner surface of the interior longitudinal bore, and at least a proximal portion of the actuator piston includes a cylindrical piston sidewall defining at least one locking aperture, the method further including mounting a locking tab within the at least one locking aperture such that the locking tab is radially translatable within the locking aperture, the locking tab engaging a step on the inner surface of the interior longitudinal bore when the locking tab extends radially beyond an outer surface of the actuator piston to prevent the actuator piston from leaving the retracted position, the locking tab being in fluid communication with the hydraulic space such that an increase in hydraulic pressure within the hydraulic space urges the locking tab inwardly within the locking aperture, The method of paragraph C1, wherein when the actuator piston is in the retracted position and the locking sleeve is in the locking position, a distal portion of the locking sleeve extending into the proximal portion of the actuator piston prevents the locking tabs from moving inwardly and disengaging from the step on the inner surface of the internal longitudinal bore, and an increase in fluid pressure in the internal hydraulic space urges the locking sleeve in a proximal direction and urges the actuator piston in a distal direction, thereby increasing the fluid pressure in the hydraulic space, causing the locking sleeve to translate in the proximal direction and allowing the locking tabs to move inwardly within the locking aperture and disengage from the step, urged by the increased fluid pressure, and allowing the actuator piston to move from the retracted position to the extended position, urged by the increased fluid pressure. C3. The method of paragraph C2, further including providing an actuator piston biasing mechanism for urging the actuator piston proximally within the internal longitudinal bore, and a locking sleeve biasing mechanism configured to urge the locking sleeve distally within the internal longitudinal bore, whereby when hydraulic pressure in the hydraulic space decreases, the actuator piston returns to a retracted position, the locking sleeve returns to a locking position, and the locking tab engages the step, locking the linear actuator. C4. The method of paragraphs C2 or C3, further including mounting a sensor adjacent a proximal end of the actuator housing and mounting an associated sensor target on a proximal end of the locking sleeve, whereby movement of the locking sleeve from one of its locking and unlocked positions to the other results in movement of the sensor target detectable by the sensor to provide an indication of whether the linear actuator is locked or unlocked. C5. The method of any of paragraphs C2-C4, further comprising coupling the hydraulic space to a source of pressurized hydraulic fluid. C6. The method of paragraph C5, further including coupling the actuator housing to an engine of the aircraft and coupling the actuator piston to a thrust reverser. C7. The method of C6, further comprising coupling the thrust reverser to one or more additional linear actuators, and linking each of the coupled linear actuators to a synchronizing mechanism such that operation of the coupled linear actuators is synchronized.

[0055] (6) Advantages, Features, and Benefits The locking linear actuators disclosed herein, thrust reverser systems that may include one or more of the disclosed locking linear actuators, and methods of manufacturing the disclosed locking linear actuators provide significant benefits compared to prior linear actuator designs, particularly with respect to the operation of thrust reversers in aircraft engines.

[0056] The locking linear actuator of the present disclosure requires fewer and less expensive parts than existing linear actuators. The new actuator exhibits reduced internal wear and the improved mechanism is simpler to manufacture than previous actuator designs. For example, the actuator cylinder is slimmer and simpler and does not need to be machined from a large initial piece of stock, reducing costs. Like the actuator cylinder, the locking sleeve of the locking actuator of the present disclosure is smaller and more streamlined than that of previous linear actuators, saving material and reducing the overall size and weight of the actuator, resulting in fuel savings.

[0057] The slimmer and smaller geometries of the linear actuators of the present disclosure also enable them to be mounted in aircraft that cannot accommodate larger existing linear actuators or may require smaller housings when they are installed.

[0058] The mechanism for lock engagement in the linear actuator of the present disclosure is simpler yet stronger and more reliable than existing locking mechanisms. The new locking mechanism also eliminates a potential source of wear created in previous linear actuators. An improved lock sensor system provides both visual confirmation of lock engagement at the actuator itself as well as electronic confirmation in the aircraft cockpit.

[0059] Additionally, the linear actuator of the present disclosure is configured such that upon unlocking of the linear actuator, disengagement of the locking sleeve occurs very quickly, with the locking sleeve being completely disengaged before the actuator piston can begin to move.

[0060] The locking linear actuator described herein is smaller, simpler to operate and manufacture, and provides a more robust locking engagement than previously disclosed locking linear actuators, particularly for thrust reverser system applications.

[0061] (7) conclusion The disclosure above may encompass a number of individual embodiments with separate utility. While each of these inventions has been disclosed in its preferred form(s), numerous variations are possible and therefore the specific embodiments disclosed and illustrated herein should not be taken in a limiting sense. As used within this disclosure, the section headings are for organizational purposes only. The subject matter of the present disclosure includes all novel and inventive combinations and subcombinations of the various elements, features, functions, and / or properties disclosed herein. The claims that follow specifically refer to certain combinations and subcombinations that are deemed novel and inventive. Other combinations and subcombinations of features, functions, elements, and / or properties may be claimed in applications claiming priority from this or a related application. Moreover, such claims, whether broader, narrower, equal, or different in scope than the claims originally filed, are deemed to be within the scope of the subject matter of the present disclosure.

Claims

1. A rocking linear actuator (20), comprising: an actuator housing (22) defining an internal longitudinal bore (30); an actuator piston (28) disposed within the internal longitudinal bore (30), the actuator piston configured for sliding movement between a proximal retracted position and a distal extended position; a locking sleeve (34) disposed within the internal longitudinal bore (30), the locking sleeve configured for slidable movement between a distal locking position and a proximal unlocked position; an actuator piston biasing mechanism (82) configured to urge the actuator piston (28) proximally within the internal longitudinal bore (30) toward the retracted position; Equipped with a locking linear actuator, wherein when the actuator piston (28) is in the retracted position and the locking sleeve (34) is in the locking position, a distal portion (64) of the locking sleeve extends into a proximal portion (36) of the actuator piston (28) to prevent the actuator piston from leaving the retracted position.

2. At least a proximal portion (36) of the actuator piston (28) defines a cylindrical piston sidewall (38), the cylindrical piston sidewall (38) defining a locking aperture (40) therein; a locking tab (42) disposed within said locking aperture (40) such that said locking tab (42) is radially translatable within said locking aperture; 2. The locking linear actuator of claim 1, wherein an inner surface (44) of the internal longitudinal bore (30) defines a step (46), the step being positioned such that when the actuator piston (28) is in the retracted position and the locking tab (42) in the locking aperture (40) extends beyond the cylindrical piston sidewall (38) of the actuator piston (28), the locking tab engages the step on the inner surface, thereby preventing the actuator piston (28) from leaving the retracted position.

3. 3. The locking linear actuator of claim 2, wherein when the actuator piston is in the retracted position and the locking sleeve is in the locked position, a distal portion of the locking sleeve extends into a proximal portion of the actuator piston to prevent the locking tabs from moving inwardly and disengaging from the step on the inner surface of the internal longitudinal bore.

4. 4. The locking linear actuator of claim 3, wherein the actuator housing (22) further defines a hydraulic space disposed between the actuator piston (28) and the locking sleeve (34), such that an increase in hydraulic pressure in the hydraulic space (72) urges the locking sleeve in a proximal direction and urges the actuator piston (28) in a distal direction.

5. said hydraulic space (72) being in fluid communication with a portion of said internal longitudinal bore (30) defining said step (46), such that an increase in hydraulic pressure within said hydraulic space (72) urges said locking tabs (42) inwardly within said locking apertures (40); 5. The locking linear actuator of claim 4, whereby increasing the hydraulic pressure in the hydraulic space (72) urges the locking sleeve proximally from the locked position to the unlocked position, thereby allowing the locking tabs (42) to move inwardly within the locking apertures (40) and disengage from the steps (46), urged by the increased hydraulic pressure, and allowing the actuator piston (28) to move from the retracted position to the extended position, urged by the increased hydraulic pressure.

6. A rocking linear actuator as described in claim 5, wherein the actuator piston biasing mechanism (82) is configured to urge the actuator piston (28) back to the retracted position when the hydraulic pressure in the hydraulic space (72) decreases.

7. 7. The locking linear actuator of claim 5, further comprising a locking sleeve biasing mechanism configured to urge the locking sleeve distally within the internal longitudinal bore such that the locking sleeve returns to the locked position upon reduction in hydraulic pressure in the hydraulic space.

8. 8. The locking linear actuator of claim 5, further configured such that returning of the actuator piston to the retracted position and the locking sleeve to the locking position urges the locking tabs radially outwardly into engagement with the steps, thereby locking the actuator piston in the retracted position.

9. 9. The locking linear actuator of claim 5, wherein the hydraulic space (72) disposed between the actuator piston (28) and the locking sleeve (34) further comprises a controllable hydraulic fluid source coupled to a synchronization mechanism (84) coupled to one or more further linear actuators, the synchronization mechanism being configured to coordinate simultaneous operation of the linear actuators.

10. 10. The locking linear actuator of claim 1, further comprising a sensor (88) disposed adjacent a proximal end of the actuator housing (22) configured to detect an associated sensor target (90) coupled to a proximal end of the locking sleeve (34) such that movement of the locking sleeve (34) from the locked position to the unlocked position is detectable by the sensor.

11. 11. The locking linear actuator of claim 10, wherein the sensor target (90) includes a deactivation region (98) detectable by the sensor (88) when the locking sleeve (34) is in the locked position, and a first activation region (94) detectable by the sensor when the locking sleeve (34) is in the unlocked position.

12. A method of manufacturing a locking linear actuator (20), comprising the steps of: Manufacturing an elongated actuator housing (22) defining an internal longitudinal bore (30); disposing an actuator piston (28) within said internal longitudinal bore (30) such that said actuator piston is slidably movable between a proximal retracted position and a distally extended position; providing an actuator piston biasing mechanism (82) that urges the actuator piston (28) proximally within the internal longitudinal bore (30) toward the retracted position; and installing a locking sleeve (34) within the internal longitudinal bore (30) proximal to the actuator piston (28) such that the locking sleeve is slidably movable between a distal locked position and a proximal unlocked position, whereby when the actuator piston is in the retracted position and the locking sleeve is in the locking position, a distal portion (64) of the locking sleeve extends into a proximal portion (36) of the actuator piston to prevent the actuator piston from leaving the retracted position.

Images