Patent Description:
At least certain gas turbine engines include, in serial flow arrangement, a compressor section including a low pressure compressor and a high-pressure compressor for compressing air flowing through the engine, a combustor for mixing fuel with the compressed air such that the mixture may be ignited, and a turbine section including a high pressure turbine and a low pressure turbine for providing power to the compressor section.

Within one or more of the sections, at least certain gas turbine engines define an annular opening. Certain of these annular openings may vary in size and shape, such that a dedicated, specialized insertion tool must be utilized with each annular opening to extend around and through such annular opening. The aviation service industry continues to demand improvements to insertion tools to increase versatility and reduce the number of individual components required on site during servicing operations.

<CIT> relates to a selectively flexible extension tool. <CIT> relates to in situ gas turbine prevention of crack growth progression. <CIT> relates to an in situ boroblending tool.

In one exemplary embodiment of the present disclosure, a tool as claimed in claim <NUM> is provided.

According to another exemplary embodiment, a method as claimed in claim <NUM> is provided.

Reference now will be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings.

Moreover, each example is provided by way of explanation of the invention, not limitation of the invention.

As used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

In general, an insertion tool in accordance with one or more embodiments described herein can be configured to permit an operator or robotic assembly to inspect a cavity, such as an internal volume of a gas turbine engine. The insertion tool can generally include first and second flexible continua which, when combined, form a substantially rigid structure having selectively arranged geometry in view of the cavity to be inserted into. Each of the flexible continuum may define half of the tool, as seen in the rigid configuration. In certain instances, the insertion tool can be fed into the cavity while simultaneously being shaped by one or more driving or engagement elements described herein. In an embodiment, the geometric shape of the rigid structure can be controlled by the engagement element(s). By way of example, the engagement element(s) can define a desirable shape which can be transferred to the first and second flexible continua to form the rigid structure. Use of various shaped engagement element(s) can allow for selective shaping of the rigid structure in view of the spatial arrangement of the cavity to be inspected or otherwise operated within. In accordance with an embodiment the continua require no dimensional accuracy along the longitudinal direction while simultaneously permitting curvature of the insertion tool. As a result, the insertion tool may be easier and cheaper to manufacture while exhibiting a relatively prolonged operating lifespan.

Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures, <FIG> is a schematic cross-sectional view of a gas turbine engine in accordance with an exemplary embodiment of the present disclosure. More particularly, for the embodiment of <FIG>, the gas turbine engine is a high-bypass turbofan jet engine <NUM>, referred to herein as "turbofan engine <NUM>. " As shown in <FIG>, the turbofan engine <NUM> defines an axial direction A (extending parallel to a longitudinal centerline <NUM> provided for reference) and a radial direction R. The turbofan engine <NUM> also defines a circumferential direction C (see <FIG>) extending circumferentially about the axial direction A. In general, the turbofan <NUM> includes a fan section <NUM> and a turbomachine <NUM> disposed downstream from the fan section <NUM>.

The exemplary turbomachine <NUM> depicted is generally enclosed within a substantially tubular outer casing <NUM> that defines an annular inlet <NUM> and an annular exhaust <NUM>. The outer casing <NUM> encases, in serial flow relationship, a compressor section including a booster or low pressure (LP) compressor <NUM> and a high pressure (HP) compressor <NUM>; a combustion section <NUM>; a turbine section including a high pressure (HP) turbine <NUM> and a low pressure (LP) turbine <NUM>; and a jet exhaust nozzle section <NUM>. A high pressure (HP) shaft or spool <NUM> drivingly connects the HP turbine <NUM> to the HP compressor <NUM>. A low pressure (LP) shaft or spool <NUM> drivingly connects the LP turbine <NUM> to the LP compressor <NUM>. The compressor section, combustion section <NUM>, turbine section, and nozzle section <NUM> together define a core air flowpath <NUM> therethrough.

For the embodiment depicted, the fan section <NUM> includes a fixed pitch fan <NUM> having a plurality of fan blades <NUM>. The fan blades <NUM> are each attached to a disk <NUM>, with the fan blades <NUM> and disk <NUM> together rotatable about the longitudinal axis <NUM> by the LP shaft <NUM>. For the embodiment depicted, the turbofan engine <NUM> is a direct drive turbofan engine, such that the LP shaft <NUM> drives the fan <NUM> of the fan section <NUM> directly, without use of a reduction gearbox. However, in other exemplary embodiments of the present disclosure, the fan <NUM> may instead be a variable pitch fan, and the turbofan engine <NUM> may include a reduction gearbox, in which case the LP shaft <NUM> may drive the fan <NUM> of the fan section <NUM> across the gearbox.

Referring still to the exemplary embodiment of <FIG>, the disk <NUM> is covered by rotatable front hub <NUM> aerodynamically contoured to promote an airflow through the plurality of fan blades <NUM>. Additionally, the exemplary turbofan engine <NUM> includes an annular nacelle assembly <NUM> that circumferentially surrounds the fan <NUM> and/or at least a portion of the turbomachine <NUM>. For the embodiment depicted, the nacelle assembly <NUM> is supported relative to the turbomachine <NUM> by a plurality of circumferentially-spaced outlet guide vanes <NUM>. Moreover, a downstream section <NUM> of the nacelle assembly <NUM> extends over an outer portion of the casing <NUM> so as to define a bypass airflow passage <NUM> therebetween. The ratio between a first portion of air through the bypass airflow passage <NUM> and a second portion of air through the inlet <NUM> of the turbomachine <NUM>, and through the core air flowpath <NUM>, is commonly known as a bypass ratio.

It will be appreciated that although not depicted in <FIG>, the turbofan engine <NUM> may further define a plurality of openings allowing for inspection of various components within the turbomachine <NUM>. For example, the turbofan engine <NUM> may define a plurality of borescope openings at various axial positions within the compressor section, combustion section <NUM>, and turbine section. Additionally, as will be discussed below, the turbofan engine <NUM> may include one or more igniter ports within, e.g., the combustion section <NUM> of the turbomachine <NUM>, that may allow for inspection of the combustion section <NUM>.

It should further be appreciated that the exemplary turbofan engine <NUM> depicted in <FIG> is by way of example only, and that in other exemplary embodiments, the turbofan engine <NUM> may have any other suitable configuration, including, for example, any other suitable number of shafts or spools, turbines, compressors, etc. Additionally, or alternatively, in other exemplary embodiments, any other suitable turbine engine may be provided. For example, in other exemplary embodiments, the turbine engine may not be a turbofan engine, and instead may be configured as a turboshaft engine, a turboprop engine, turbojet engine, etc..

Referring now to <FIG>, a close-up, schematic view of the combustion section <NUM> of the turbomachine <NUM> of the exemplary gas turbine engine <NUM> of <FIG> is provided along with a tool <NUM> for insertion into an annular section of the engine <NUM>. It will be appreciated that although the tool <NUM> is depicted in <FIG>, and described below, as being inserted into a combustion section <NUM>, in other exemplary embodiments, the tool <NUM> may additionally, or alternatively, be inserted into other areas of the turbofan engine <NUM> having an annular shape or other shape. For example, the tool <NUM> may be inserted into annular sections of the compressor section or the turbine section, or alternatively still, other engines or systems altogether. Additionally or alternatively, still, the tool <NUM> may be inserted into a non-annular section.

As is depicted, the combustion section <NUM> generally includes a combustor <NUM> positioned within a combustor casing <NUM>. Additionally, the combustor <NUM> includes an inner liner <NUM>, an outer liner <NUM>, and a dome <NUM> together defining at least in part a combustion chamber <NUM>. It will be appreciated that the dome <NUM>, for the embodiment depicted, is an annular dome and the combustor <NUM> is configured as an annular combustor. In such a manner, the combustion chamber <NUM> generally defines an annular shape. At a forward end <NUM>, the combustor <NUM> defines, or rather, the dome <NUM> defines, a nozzle opening <NUM>, and the combustion section <NUM> further includes a fuel-air mixer <NUM>, or nozzle, positioned within the nozzle opening <NUM>. The fuel-air mixer <NUM> is configured to provide a mixture of fuel and compressed air to the combustion chamber <NUM> during operation of the turbofan engine <NUM> to generate combustion gases. The combustion gases flow from the combustion chamber <NUM> to the HP turbine <NUM>, and more specifically, through a plurality of inlet guide vanes <NUM> of the HP turbine <NUM>.

Notably, although a single nozzle opening <NUM> and fuel-air mixer <NUM> is depicted in <FIG>, the combustor <NUM> may further include a plurality of circumferentially spaced nozzle openings <NUM> and a respective plurality of fuel-air mixers <NUM> positioned within the nozzle openings <NUM>.

In order to initiate a combustion of the fuel and compressed air provided to the combustion chamber <NUM> by the fuel-air mixer <NUM>, the combustion section <NUM> typically includes one or more igniters (not installed or depicted) extending through respective igniter openings <NUM> defined in the combustor casing <NUM> and the outer liner <NUM> of the combustor <NUM>. However, when the turbofan engine <NUM> is not operating, the igniter(s) may be removed and the igniter opening(s) <NUM> may be utilized for inspecting, e.g., the combustion chamber <NUM>, inlet guide vanes <NUM> of the HP turbine <NUM>, and/or other components.

More specifically, for the embodiment of <FIG>, the tool <NUM> capable of insertion into an annular section of an engine is depicted extending through the pair of igniter openings <NUM> defined in the combustor casing <NUM> and the outer liner <NUM> of the combustor <NUM>.

Referring now also to <FIG>, providing a partial, axial cross-sectional view of the combustion section <NUM> of <FIG>, it will be appreciated that the tool <NUM> generally includes a plurality of continua, such as a first continuum <NUM> and a second continuum <NUM>, movable into the combustion chamber <NUM>. The first and second continua <NUM> and <NUM> can be joined together along a connection interface schematically depicted in <FIG> by a dashed line <NUM>. The connection interface <NUM> extends continuously along the length of the tool <NUM>. As illustrated in <FIG>, and according to certain embodiments, the connection interface <NUM> can remain in a one- or two-dimensional spatial arrangement. That is, the connection interface <NUM> may not twist, e.g., helically, around a circumference of the tool <NUM> in a third-dimension of, e.g., a cartesian coordinate system.

In certain instances, the tool <NUM> can define one or more linear portions <NUM> and one or more bent portions <NUM>. The bent portions <NUM> can define radii of curvature, e.g., Ri. The radius of curvature of the illustrated bent portion <NUM> can be disposed within a single plane. That is, for example, as described above, the radius of curvature of the bent portion <NUM> of the tool <NUM> can be defined by a single plane.

A distal end <NUM> of the tool <NUM> can include an implement, which for the embodiment depicted is a camera <NUM>, to allow for inspection of various components of the combustor <NUM> and/or high pressure turbine <NUM>. It will be appreciated, however, that the insertion tool <NUM> may include any other suitable implement, such that the insertion tool <NUM> may be utilized for any suitable purpose. For example, the insertion tool <NUM> may be utilized to inspect the interior of the engine using, e.g., the camera <NUM>. Additionally, or alternatively, the insertion tool <NUM> may include various other tool implements to perform one or more maintenance operations within the interior of the engine (e.g., drilling, welding, heating, cooling, cleaning, spraying, etc.).

Further, the exemplary insertion tool <NUM> can include a drive assembly <NUM> for driving the insertion tool <NUM> into, or out of, the interior of the engine, and more specifically for the embodiment shown, into or out of the combustion chamber <NUM>. The drive assembly <NUM> may be operably coupled to a controller or other control device, such that a length of the insertion tool <NUM> within the interior of the engine may be controlled with relative precision by the drive assembly <NUM>.

In an embodiment, the drive assembly <NUM> can include an engagement mechanism <NUM> configured to join the first and second continua <NUM> and <NUM> together to form the tool <NUM>. In another embodiment, the engagement mechanism <NUM> and drive assembly <NUM> can be discrete, i.e., separate, components. For example, the engagement mechanism <NUM> can be separate from the drive assembly <NUM> such that the drive assembly <NUM> interfaces only with the individual first and second continua <NUM> and <NUM>. The engagement mechanism <NUM> may be used to selectively join the first and second continua <NUM> and <NUM> together to form the tool <NUM>. In certain instances, the engagement mechanism <NUM> can define one or more selected shapes which can be transferred to the tool <NUM> during the step of connecting the first and second continua <NUM> and <NUM> together. In such a manner, the engagement mechanism <NUM> can be, e.g., interchanged to permit an operator to adjust the shape of the resulting tool <NUM>. In an embodiment, the engagement mechanism <NUM> can be selected from a plurality of different engagement mechanisms with at least two of the plurality of different engagement mechanisms having different shapes as compared to one another. The operator can select the appropriately shaped engagement mechanism from the plurality of different engagement mechanisms based on the engine being serviced.

In an embodiment, the engagement mechanism <NUM> can be a variable shaped engagement mechanism. In such a manner, the operator can selectively shape the engagement mechanism <NUM> to achieve a desired shape of the resulting tool <NUM>. By way of example, the variable shaped engagement mechanism can include an actuated flexible or hinged section which permits the operator to select desired bend shapes and sizes for the environment being operated within.

<FIG> illustrates a perspective view of the tool <NUM> as seen in accordance with an exemplary embodiment during a process of joining the first and second continua <NUM> and <NUM> together so as to form a substantially rigid structure for performing a service, e.g., inspection and/or operation, in a cavity of equipment, such as aircraft engines. In this regard, a shape of the upper portion of the tool <NUM> is not yet defined, while the lower portion of the tool <NUM> includes interconnected first and second continua <NUM> and <NUM>, thus defining the shape of the lower portion of the tool <NUM>.

illustrates a cross-sectional side view of the first continuum <NUM> and the second continuum <NUM> of the insertion tool <NUM> in accordance with an exemplary embodiment of the present disclosure as seen along Line A-A in <FIG>. The tool <NUM> is generally travelling in a direction D into or away from an area of interest, e.g., an inspection area of an engine. As illustrated, the first and second continua <NUM> and <NUM> are separate at a first location <NUM> and join together to form the tool <NUM> at a mesh point <NUM>, e.g., where the aforementioned engagement mechanism <NUM> (<FIG>) is located. In certain instances, the mesh point <NUM> can include an area where one or more coupling force(s), e.g., inward forces F, transverse to longitudinal lengths of the first and second continua <NUM> and <NUM>, are applied to the first and second continua <NUM> and <NUM>. In an embodiment, the coupling force can be generated, for example, at a discrete location within the mesh point <NUM>. In another embodiment, the coupling force can be generated at a plurality of locations within the mesh point <NUM> or along a continuous length of the mesh point <NUM>. That is, for example, the forces F can be generated by a ramped interface that progressively narrows the distance between the first and second continua <NUM> and <NUM>. The mesh point <NUM> can transition the first and second continua <NUM> and <NUM> from a detached (i.e., decoupled) configuration to an attached configuration so as to form the tool <NUM>.

As illustrated in <FIG>, the distal end <NUM> of the tool <NUM> can be formed, at least in part, by both the first and second continua <NUM> and <NUM>. For example, the first and second continua <NUM> and <NUM> can be aligned such that half of the distal end <NUM> is defined by the first continuum <NUM> and the other half of the distal end <NUM> is defined by the second continuum <NUM>. In such a manner, individual distal ends 112A and 112B of the first and second continua <NUM> and <NUM>, respectively, can be coplanar. As a result, inclusion of one or more bent portions, such as, e.g., bent portion <NUM>, can cause the relative lengths of the first and second continua <NUM> and <NUM> actively forming part of the rigid portion of the tool <NUM> to be different from one another. As used herein, active parts of the tool <NUM> may refer to those portions of the tool <NUM> where the first and second continua <NUM> and <NUM> are coupled together to form the substantially rigid tool. Conversely, inactive parts of the tool <NUM> can refer to those portions of the first and second continua <NUM> and <NUM> that are not joined together. As illustrated in <FIG>, the second continuum <NUM> has a shorter distance to travel around the bent portion <NUM> as a result of being on a side of the tool <NUM> radially inside of the first continuum <NUM>. Accordingly, more of the first continuum <NUM> is required to maintain the tool <NUM> with the bent portion <NUM>. Conversely, introduction of a second bent portion (not illustrated) in the tool <NUM> having an equal but opposite radius of curvature to the bent portion <NUM> (e.g., an S-curve formed of equal bend radii) may result in the effective lengths of the first and second continua <NUM> and <NUM> being equal as measured upstream of the second bent portion.

After passing through the mesh point <NUM>, the tool <NUM> can have a rigid construction. That is, the profile of the tool <NUM> (e.g., any curvatures defined therein) can remain relatively fixed downstream of the mesh point <NUM>. In such a manner, the curvature of the tool <NUM> may be determined in anticipation of the shape and/or size of the cavity being inspected or operated on by the tool <NUM>.

To facilitate bending of the tool <NUM>, at least one of the first and second continua <NUM> and <NUM>, such as both the first and second continua <NUM> and <NUM>, can include a plurality of C-shaped portions <NUM> coupled together through an elongated structure <NUM>. The elongated structure <NUM> may extend continuously along the length of the first and/or second continua <NUM> and <NUM>. In certain instances, the elongated structure <NUM> may include a single elongated structure extending along the entire length of the first and/or second continua <NUM> and <NUM>. In other instances, the elongated structure <NUM> can include a plurality of elongated structures joined together.

In an embodiment, at least one of the first and second continua <NUM> and <NUM>, such as both the first and second continua <NUM> and <NUM>, can include a single, e.g., monolithic, component. For example, the first continuum <NUM> can include a single-piece structure comprising a single elongated structure <NUM> and a plurality of interspaced C-shaped portions <NUM>. In other embodiments, at least one of the first and second continua <NUM> and <NUM> can include a multi-piece construction. For instance, the elongate structure <NUM> can include a first material and the C-shaped portions <NUM> can include a second material different than the first material. By way of example, the elongated structure <NUM> can include a more readily deformable material as compared to the material of the C-shaped portions <NUM>. The C-shaped portions <NUM> can include more resilient materials as compared to the elongated structure <NUM>. One exemplary material for the elongated structure <NUM> includes spring steel. Other materials include stainless steel, nitinol, beryllium copper, and other materials which exhibit generally elastic behavior. In certain instances, at least one of the C-shaped portions <NUM> can be attached to the elongated structure <NUM> through over-molding, fusion, adhesive, and the like.

While flexure of the first continuum <NUM> may occur at any location along the length thereof, in certain instances a majority of bending can occur at the elongated structure <NUM> between adjacent C-shaped portions <NUM>. The relative amount of obtainable flexure of the tool <NUM> can be determined at least in part by dimensions of gaps <NUM> between adjacent C-shaped portions <NUM>. For instance, the relative lengths <NUM> and widths <NUM> of the gaps <NUM> can define a maximum bend angle between adjacent C-shaped portions <NUM>. Narrow gaps <NUM> in the direction <NUM> may cause reduced bending. Similarly, long gaps <NUM> in the direction <NUM> may reduce bending. While the gaps <NUM> are shown in <FIG> as having equal dimensions and geometry as compared to one another, in certain instances, the gaps <NUM> may define variable sizing and/or variable geometry as compared to one another.

<FIG> illustrates a cross-sectional view of the first and second continua <NUM> and <NUM> of the insertion tool <NUM> of <FIG>, as seen along Line B-B, in accordance with an exemplary embodiment of the present disclosure. The portion of the first and second continua <NUM> and <NUM> illustrated in <FIG> is upstream of the mesh point <NUM>. Accordingly, the first and second continua <NUM> and <NUM> are not yet joined together. <FIG> illustrates a cross-sectional view of the first and second continua <NUM> and <NUM> of the insertion tool <NUM> of <FIG>, as seen along Line C-C, in accordance with an exemplary embodiment of the present disclosure. The portion of the first and second continua <NUM> and <NUM> illustrated in <FIG> is downstream of the mesh point <NUM>. Accordingly, the first and second continua <NUM> and <NUM> are joined together to form the tool <NUM>.

As illustrated in the exemplary embodiment of <FIG>, the first and second continua <NUM> and <NUM> may be generally the same as compared to one another. For instance, the first and second continua <NUM> and <NUM> may be reflectively or rotationally symmetrical with one another. Reference made hereinafter to the first continuum <NUM>, or features thereof, may thus be applicable to both the first and second continuum <NUM> and <NUM>. Alternatively, one or more features of the first and second continua <NUM> and <NUM> may be different from one another.

Referring to <FIG>, the first continuum <NUM> can include a generally C-shaped body <NUM>. The elongated structure <NUM> can form, or be part of, the middle section of the C-shaped body <NUM>. First and second arms <NUM> and <NUM> can extend from the middle section of the C-shaped body <NUM>, e.g., from the elongated structure <NUM>. In certain embodiments, the lengths of the first and second arms <NUM> and <NUM> can be generally the same as one another. In other embodiments, the lengths of the first and second arms <NUM> and <NUM> can be different as compared to one another.

In the illustrated embodiment, the first arm <NUM> includes a receiver <NUM> disposed at an end thereof and configured to receive a portion of the second continuum <NUM>. The receiver <NUM> is illustrated as a channel having a U-shape into which a second arm <NUM> of the second continuum <NUM> can be inserted. The receiver <NUM> can include one or more features <NUM> configured to increase the necessary force required to decouple the first and second continua <NUM> and <NUM> from one another. In the illustrated embodiment, the one or more features <NUM> includes a projection extending into the U-shaped channel so as to form an interference fit with the second arm <NUM> of the second continuum <NUM>. In other embodiments, the one or more features <NUM> can include any one or more of tines, barbs, scallops, undulations, castellations, or other geometry configured to grip the second arm <NUM> of the second continuum <NUM>. The one or more features <NUM> may operate in multiple directions to prevent undesirable movement between the first and second continua <NUM> and <NUM>. For instance, in addition to maintaining the first and second continua <NUM> and <NUM> in engagement with one another, the one or more features <NUM> can prevent longitudinal displacement between the first and second continua <NUM> and <NUM>.

In the illustrated embodiment, the second arm <NUM> has a generally linear geometry configured to extend into a receiver <NUM> of the second continuum <NUM>. A guide feature <NUM> may be disposed on the second arm <NUM> to prevent overinsertion of the second arm <NUM> into the receiver <NUM>. Moreover, the guide feature <NUM> may be useful for an observer or control system in preventing underinsertion. That is, the observer or control system can determine if the guide feature <NUM> is too far spaced apart from the receiver <NUM> in the installed state. Gaps between the guide feature <NUM> and receiver <NUM> exceeding a threshold distance may be indicative of non-fully engaged first and second continua <NUM> and <NUM>.

In other embodiments, the contact interface <NUM> may be formed by one or more additional or other methods different than the aforementioned frictional or interference fits. For example, the contact interface <NUM> may be formed through electrostatic adhesion, magnetic attraction, chemical adhesion (e.g., thermal set glue), through van der Waals forces (e.g., gecko-type, sticky feet), and the like. Moreover, these contact interfaces <NUM> may be formed using a plurality of different types of attachment protocol.

Referring to <FIG>, the guide feature <NUM> may remain spaced apart from the receiver <NUM> in the engaged, i.e., coupled, configuration. The guide feature <NUM> may form an interface for one or more components to operate on the tool <NUM>. For instance, the gap between the guide feature <NUM> and receiver <NUM> may permit a tool to slide between the guide feature <NUM> and receiver <NUM> to separate the first and second continua <NUM> and <NUM> from one another.

In the coupled configuration illustrated in <FIG>, the first and second continua <NUM> and <NUM> can combine to form a rigid structure of the tool <NUM>. A volume <NUM> can be defined within the first and second continua <NUM> and <NUM>. The volume <NUM> can permit routing of one or more tooling components or tooling support cables, wires, and the like. The size of the volume <NUM> may remain substantially constant along the length of the tool <NUM>.

<FIG> illustrates an elevation view of the first continuum <NUM> as seen along Line D-D in <FIG>. The elongated structure <NUM> is shown having a plurality of C-shaped portions <NUM> extending therefrom. In the exemplary embodiment depicted in <FIG>, each C-shaped portion <NUM> includes a first portion 124A and a second portion 124B spaced apart by the elongated structure <NUM>. In certain instances, the first and second portions 124A and 124B can be reflectively symmetrical in arrangement about the elongated structure <NUM>. In other instances, the first and second portions 124A and 124B can be staggered or longitudinally offset from one another along a longitudinal direction of the first continuum <NUM>. It is noted that complete longitudinal offset between the first and second portions 124A and 124B may reduce flexibility of the elongated structure <NUM> of the first and second continua <NUM> and <NUM>. Additional features, such as cutouts and the like, may be utilized to re-introduce flexibility into the elongated structure <NUM>.

At least one of the first and second portions 124A and 124B of at least one of the C-shaped portions <NUM> can have a narrow base <NUM> and a wider head <NUM>. The narrow base <NUM> may facilitate easier bending of the first continuum <NUM> by reducing a length of the elongated structure <NUM> fixed to the C-shaped portions <NUM>. By way of example, the narrow base <NUM> can define a longitudinal dimension <NUM> that is no greater than <NUM>% the longitudinal dimension <NUM> of the wider head <NUM>, such as no greater than <NUM>% the longitudinal dimension <NUM>, such as no greater than <NUM>% the longitudinal dimension <NUM>, such as no greater than <NUM>% the longitudinal dimension <NUM>, such as no greater than <NUM>% the longitudinal dimension <NUM>, such as no greater than <NUM>% the longitudinal dimension <NUM>, such as no greater than <NUM>% the longitudinal dimension <NUM>, such as no greater than <NUM>% the longitudinal dimension <NUM>, such as no greater than <NUM>% the longitudinal dimension <NUM>, such as no greater than <NUM>% the longitudinal dimension <NUM>. In certain instances, the base <NUM> can taper from a narrowest point closest to the elongated structure <NUM> to a widest part adjacent to the head <NUM>.

<FIG> illustrates a tool system <NUM> for forming the tool <NUM> in accordance with one or more exemplary embodiments described herein. The tool system <NUM> includes the aforementioned engagement mechanism <NUM> for joining the first and second continua <NUM> and <NUM> together. As depicted in <FIG>, the tool system <NUM> comprises a storage area <NUM> configured to store portions of at least one of the first and second continua <NUM> and <NUM> that are not actively part of the tool <NUM>. Portions of the first and second continua <NUM> and <NUM> that are not actively part of the tool include those portions of the continua <NUM> and <NUM> that are not yet joined together. For example, a first portion of the first continuum <NUM> can be disposed on a first side of the engagement mechanism <NUM> (the first side being associated with the tool <NUM>) and a second portion of the first continuum <NUM> can be disposed on a second side of the engagement mechanism <NUM>. The second portion can correspond with the portion of the continuum <NUM> not actively part of the tool <NUM> at a given moment. Lengths of the first and second portions can change inversely with respect to one another.

In an embodiment, the storage area <NUM> can include a first storage area <NUM> for storing inactive portions of the first continuum <NUM> and a second storage area <NUM> for storing inactive portions of the second continuum <NUM>. In certain instances, the first and second storage areas <NUM> and <NUM> can be configured to store the first and second continua <NUM> and <NUM>, respectively, in rolled configurations. That is, the deflectable radius of curvature of the first and second continua <NUM> and <NUM> can permit rolled, space- efficient storage for those portions of the first and second continua <NUM> and <NUM> not being actively used by the tool <NUM>. By way of example, at least one of the first and second storage areas <NUM> and <NUM> can include a rotatable element, such as a rotatable spool. As the tool <NUM> is biased away from the engagement mechanism <NUM>, the first and second storage areas <NUM> and <NUM> can unwind the first and second continua <NUM> and <NUM>, respectively, to feed the engagement mechanism <NUM> and elongate the tool <NUM>. Similarly, as the tool <NUM> is biased toward the engagement mechanism <NUM>, the first and second storage areas <NUM> and <NUM> can wind the first and second continua <NUM> and <NUM>, respectively to store the first and second continua <NUM> and <NUM>.

In another embodiment, at least one of the first and second storage areas <NUM> and <NUM> can operate through a different mechanism as compared to the aforementioned rotational operational protocol. For example, the first and second continua <NUM> and <NUM> can be laid linearly in a storage area, optionally including bent portions to create a zigzag, or other similar, pattern.

In certain instances, at least one of the first and second storage areas <NUM> and <NUM> can be driven. That is, unwinding and/or winding the first and second continua <NUM> and <NUM> can be at least in part performed by rotatably biasing the first and/or second storage areas <NUM> and <NUM>. In other instances, at least one of the first and second storage areas <NUM> and <NUM> can be passive. In such a manner, winding and/or unwinding the first and second continua <NUM> and <NUM> relative to the first and second storage areas <NUM> and <NUM>, respectively, can be performed by a separate component, such as the driving mechanism <NUM>.

In an embodiment, at least one of the first and second continua <NUM> and <NUM> may remain at least partially engaged with the engagement mechanism <NUM> when in a fully stored position, i.e., when the first and second continua <NUM> and <NUM> are not actively used to form the tool <NUM>. That is, the first and/or second continua <NUM> and <NUM> may not be fully stored (e.g., wound) on the first and second storage areas <NUM> and <NUM> in the stored position. Instead, the distal ends 112A and 112B can remain coupled with the engagement mechanism <NUM>. This may facilitate easier formation of a future tool <NUM> without requiring refeeding of the first and second continua <NUM> and <NUM> thereinto.

After finishing each successive use of the tool <NUM>, the first and second continua <NUM> and <NUM> may be retracted at least partially into the first and second storage areas <NUM> and <NUM>. The distal ends 112A and 112B may be maintained at relatively fixed longitudinal locations with respect to one another in the stored position.

In an embodiment, at least one of the first and second continua <NUM> and <NUM> can define a length no less than the length of the tool <NUM>. In a particular embodiment, both the first and second continua <NUM> and <NUM> can define lengths greater than the length of the tool <NUM>.

<FIG> illustrates a cross-sectional view of an embodiment of the insertion tool <NUM> including a detachment element <NUM> disposed in alignment with the first and second continua <NUM> and <NUM> so as to separate the first and second continua <NUM> and <NUM> from one another as they are removed from the cavity. By way of non-limiting example, the detachment element <NUM> can include a wedge configured to be disposed between the first and second continua <NUM> and <NUM>. As the tool <NUM> is biased in a direction toward the detachment element <NUM>, the wedged configuration of the detachment element <NUM> (or another suitable detachment protocol) can cause the first and second continua <NUM> and <NUM> to separate from one another.

<FIG> is a flow chart of a method <NUM> of inserting a tool into a cavity. The method <NUM> includes a step <NUM> of passing a first continuum through an engagement mechanism at a first speed and a step <NUM> of passing a second continuum through the engagement mechanism at a second speed. The relative difference between the first and second speeds at steps <NUM> and <NUM> can determine a relative curvature of the tool. For example, when the first speed is greater than the second speed, the first continuum may form an outer surface of the curvature of the tool, i.e., the radius of curvature of the first continuum is greater than a radius of curvature of the second continuum. Conversely, when the second speed is greater than the first speed, the second continuum may form an outer surface of the curvature of the tool, i.e., the radius of curvature of the second continuum is greater than the radius of curvature of the first continuum. Where the first and second continua are stored in a rolled configuration, the steps <NUM> and <NUM> may be performed by unwinding the first and second continua from the rolled configuration. This may include biasing the spool on which at least one of the first and second continua are stored, or pulling the first and/or second continua from the spool by another driving mechanism.

The method <NUM> further includes a step <NUM> of coupling the first and second continua together to form the tool using the engagement mechanism. Coupling the first and second continua together when the first and second continua are travelling at different speeds results in the curvature being selectively maintained within the tool. The step <NUM> of coupling the first and second continua together using the engagement mechanism may be performed at a location near the cavity, e.g., adjacent to the cavity. As the tool is being formed at step <NUM>, a distal end thereof can pass into the cavity while the first and second continua pass through the engagement mechanism. That is, a leading portion of the tool can enter the cavity as a trailing portion behind the leading portion is being formed by the engagement mechanism.

The method <NUM> further includes a step <NUM> of adjusting the first speed to form a bend in the tool. The bend formed at step <NUM> can have a lesser or greater radius of curvature as compared to the radius of curvature of the tool at an immediately adjacent location. The step <NUM> of adjusting the first speed can be performed, for example, to achieve a certain geometry necessary to insert the tool into the cavity so as to clear obstacles and structures therein.

<FIG> is a flow chart of a method <NUM> of inserting a tool into a cavity in accordance with another exemplary embodiment. The method <NUM> includes a step <NUM> of passing a first continuum through an engagement mechanism and a step <NUM> of passing a second continuum through the engagement mechanism. The method further includes a step <NUM> of coupling the first and second continua together to form a tool using the engagement mechanism. The shape of the formed tool is defined by a shape of the engagement mechanism. In one or more instances, the operator can selectively change the engagement mechanism to change the shape imparted onto the formed tool at step <NUM>. More particularly, the operator can select the engagement mechanism from a plurality of engagement mechanisms, where at least two of the plurality of engagement mechanisms have different shapes as compared to one another. The selective change between two or more of the plurality of engagement mechanisms can occur, for example, when the operator is moving the tool between different cavities being inspected or even during the inspection of a single cavity. For example, the operator may change to a different engagement mechanism when inspecting a different engine or within the inspection process of a single engine.

Referring now to <FIG>, in accordance with the invention, the aforementioned insertion tool <NUM> is formed at least in part from one or more continua that have a multi-piece construction. Referring initially to <FIG>, an exemplary continuum <NUM> is depicted including an elongated structure <NUM> configured to receive bodies <NUM>, e.g., C-shaped bodies. The elongated structure <NUM> and bodies <NUM> can include discrete, i.e., separate, elements which can be joined together to form the continuum <NUM>. The bodies <NUM> can be similar in engagement protocol to the generally C-shaped body <NUM> previously described. In such a manner, the bodies <NUM> can be joined together to form the insertion tool <NUM> in a manner as previously described.

In certain instances, the bodies <NUM> can translate, e.g., slide, relative to the elongated structure <NUM> in a longitudinal direction L. In such a manner, the bodies <NUM> can be translated relative to the elongated structure <NUM> during formation of the continuum <NUM>. By way of non-limiting example, the bodies <NUM> can include guide features <NUM> which slide along the elongated structure <NUM>. The guide features <NUM> can include one or more rails, slots, and the like which are arranged to guide the bodies <NUM> relative to the elongated structure <NUM>. In an embodiment, at least one of the bodies <NUM> can be installed at a longitudinal end of the elongated structure <NUM>. In another embodiment, at least one of the bodies <NUM> can be installed on the elongated structure <NUM> at a location spaced apart from the longitudinal ends thereof.

The elongated structure <NUM> can include a plurality of receiving areas <NUM>, with at least some of the receiving areas <NUM>, e.g., all of the receiving areas <NUM>, being configured to receive one or more bodies <NUM>. The bodies <NUM> can be translated relative to the elongated structure <NUM> until aligning with an appropriate receiving area <NUM>. The receiving areas <NUM> can generally include mechanisms for engagement with the bodies <NUM>. By way of non-limiting example, at least one of the receiving areas <NUM> can include an opening extending into, such as through, the elongated structure <NUM>. In the illustrated embodiment, at least some of the bodies <NUM> can define an interface configured to be secured to the elongated structure <NUM> through the use of a connection component <NUM>. The interface can include, for example, an opening <NUM> configured to be aligned with one or more of the receiving areas <NUM>. In certain instances, the receiving areas <NUM> can be equally spaced apart from one another. The spacing between adjacent receiving areas <NUM> and <NUM> can be dimensioned such that the bodies <NUM> are operationally disposed to permit flexure of the continuum <NUM> during formation of the rigid portion of the tool <NUM>.

The connection component <NUM> can secure the opening <NUM> of the body <NUM> with the receiving area <NUM> of the elongated structure <NUM>. In a particular embodiment, the connection component <NUM> can be engaged at the interface by sliding the connection component <NUM> through at least a portion of the body <NUM> and the elongated structure <NUM>. By way of example, the connection component <NUM> can secure the interface by translating in a direction generally perpendicular to the longitudinal direction L which the bodies <NUM> translate relative to the elongated structure <NUM>. In an embodiment, the interface between the connection component <NUM> and at least one of the elongated structure <NUM> and body <NUM> can include a locking interface configured to prevent accidental removal of the connection component <NUM>, a tactile indicator of proper seating of the connection component <NUM>, or both. With the bodies <NUM> secured in place relative to the elongated structure <NUM>, the continuum <NUM> can be joined with another continuum to form the tool <NUM>.

<FIG> illustrates a continuum <NUM> having a different multi-piece construction in accordance with another exemplary embodiment. Unlike the embodiment illustrated in <FIG> where the bodies <NUM> translate in the longitudinal direction L relative to the elongated structure <NUM>, the continuum <NUM> depicted in <FIG> permits installation of one or more bodies <NUM> along an elongated structure <NUM> in a direction generally perpendicular to the longitudinal direction L. As illustrated, the bodies <NUM> can be installed on the elongated structure <NUM> by translating the bodies <NUM> in a direction P perpendicular, or generally perpendicular, with the longitudinal direction L of the elongated structure <NUM>. Guide features <NUM> can align the bodies <NUM> relative to the elongated structure <NUM>. For example, the guide features <NUM> can align, e.g., center, each body <NUM> relative to a transverse axis T, such that an engagement feature <NUM> of the body <NUM> is aligned with a receiving area <NUM> of the elongated structure <NUM>. The engagement feature <NUM> can engage with the receiving area <NUM> to secure the body <NUM> to the elongated structure <NUM>.

In an embodiment, the engagement feature <NUM> can be fixed to the receiving area <NUM> through a mechanical and/or chemical fastener. For example, the engagement feature <NUM> can be crimped, fastened, pinned, welded, heat fused, or otherwise mechanically attached to the receiving area <NUM> and/or chemically fastened thereto, e.g., by adhesive bonding.

It should be understood that the embodiments illustrated in <FIG> are not exclusive and that certain aspects of each embodiment can be utilized together in a non-illustrated embodiment. Multi-piece constructed continuums may permit use of different materials between the elongated structure <NUM>, <NUM> and the bodies <NUM>, <NUM>. For instance, at least one of the bodies <NUM>, <NUM> can include a first material while the elongated structure <NUM>, <NUM> can include a second material different than the first material. By way of non-limiting example, the first material can include a polymer, e.g., a molded thermoplastic, while the second material can include a metal, e.g., spring steel. In an embodiment, at least two of the bodies <NUM>, <NUM> installed on the elongated structure <NUM>, <NUM> can have different properties as compared to one another, e.g., the at least two bodies <NUM>, <NUM> can be formed from different materials as compared to one another. In such a manner, the continuum can be designed for use in particular environments where variable continuum attributes, as measured at different locations along the continuum, are desirable.

In an embodiment, the insertion tool <NUM> can be formed from a first continuum having a single-piece construction and a second continuum having a multi-piece construction. In another embodiment, the insertion tool <NUM> can be formed from similarly constructed continua, such as two single-piece continua or two multi-piece continua. In yet other embodiments, the insertion tool <NUM> can be formed from more than two continua, such as three continua, four continua, five continua, and the like.

Insertion tools in accordance with embodiments described herein may generally allow for inspection and operation within a cavity, e.g., of a gas turbine engine, without requiring complex, delicate parts that may break or become stuck within the cavity. Additionally, insertion tools in accordance with embodiments described herein may permit inspection of multiple different areas, e.g., different engines, without use of duplicative tooling specific to each engine design. Yet further, use of insertion tools in accordance with certain embodiments may eliminate longitudinal accuracy requirements between the two or more continua. That is, the continua may be joined together without requiring tight longitudinal tolerances. Moreover, using tools in accordance with certain embodiments described herein can permit infinite adjustability of the curvature and shape of the tool that permit reusability and minimal down time between insertions. This is particularly true for insertion tools which are formed using variable speeds between the first and second continua to permit control of the shape of the insertion tool.

Claim 1:
A tool for inserting into a cavity of an aircraft engine, the tool comprising:
a flexible first (<NUM>) continuum; and
a flexible second (<NUM>) continuum, wherein the first (<NUM>) and second (<NUM>) continua are selectively engageable with one another along a connection interface (<NUM>), wherein the connection interface (<NUM>) extends continuously along the length of the tool (<NUM>), and wherein when selectively engaged, the first and second continua have a substantially rigid construction for performing a service;
wherein at least one of the first and second continua comprises a plurality of bodies (<NUM>) coupled together through an elongated structure, and wherein the at least one of the first and second continua are flexible at interfaces disposed between adjacent bodies.