Patent Description:
Robotic arm assemblies are useful throughout various industries for performing operations at, e.g., remote locations, hazardous locations, etc. At least certain robotic arm assemblies include a robotic arm formed of a plurality of links joined together at respective joints. Additionally, a plurality of control wires may extend through the robotic arm, with each wire terminating at an individual link for moving such link relative to an aft-adjacent link. The control wires may be coupled to one or more motors within a base of the robotic arm assembly, such that the robotic arm assembly may control a movement of the robotic arm by increasing and/or decreasing tension on the plurality of control wires.

In such a manner, robotic arms may be useful in reaching out-of-sight locations within various environments. However, robotic arms may generally be cost prohibitive and/or more complicated than desired for certain applications. Accordingly, a tool that may allow for a user to reach remote locations within an environment in a more cost efficient manner would be useful.

<CIT> relates to a miniature TV camera system. <CIT> relates to a flexible support and carrier assembly. <CIT> relates to a flexible actuator.

In one exemplary embodiment of the present disclosure, an extension tool according to claim <NUM> is provided.

In one exemplary aspect of the present disclosure, a method for operating a selectively flexible extension tool according to claim <NUM> is provided.

For example, in certain other exemplary aspects the opening is a borescope opening.

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended Figs. , in which.

The terms "forward" and "aft" refer to relative positions of a component or system, and refer to the normal operational attitude of the component or system. For example, with regard to an extension tool in accordance with one or more the present embodiments, forward refers to a position closer to a distal end of the extension tool and aft refers to a position closer to a root end of the extension tool.

Referring now to the drawings, wherein identical numerals indicate the same elements throughout the Figs. , <FIG> is a schematic view of an extension tool <NUM> in accordance with an exemplary embodiment of the present disclosure in a slacked position; and <FIG> is a schematic view of the exemplary extension tool <NUM> of <FIG> in a tensioned position. Accordingly, it will be appreciated from the description herein that the extension tool <NUM> is a selectively flexible extension tool.

The extension tool <NUM> generally includes a base <NUM>, a line assembly <NUM>, and a plurality of sequentially arranged links <NUM>. The base <NUM> generally includes a first plate <NUM>, a second plate <NUM>, and one or more extension guides <NUM>. For the embodiment depicted, the one or more extension guides <NUM> includes a pair of extension guides <NUM> fixedly coupled to the first plate <NUM> and extending in a lengthwise direction LW. The second plate <NUM> of the base <NUM> includes openings <NUM> corresponding to the pair of extension guides <NUM>, such that the second plate <NUM> is slidable along the extension guides <NUM> in the lengthwise direction LW away from the first plate <NUM> and towards the first plate <NUM>.

The line assembly <NUM> generally includes a root <NUM> coupled to the second plate <NUM> of the base <NUM> and a plurality of lines <NUM> extending from the root <NUM>. The plurality of lines <NUM> includes a first line 118A and second line 118B. As will be appreciated from the discussion herein below, the line assembly <NUM>, and in particular the first and second lines 118A, 118B, are operable with the plurality of sequentially arranged links <NUM> to move the plurality of sequentially arranged links <NUM> between the slacked position (<FIG>) and the tensioned position (<FIG>). Further, it will be appreciated that for the embodiment depicted, although the lines are depicted as being spaced from one another in a crosswise direction CW in the embodiment depicted for explanatory purposes, they are actually aligned with one another in the crosswise direction CW for the embodiment depicted.

As will be explained in greater detail below, the plurality of sequentially arranged links <NUM> are spaced from one another when in the slacked position (<FIG>) to allow the plurality of sequentially arranged links <NUM> to pivotably move relative to one another. By contrast, the plurality of sequentially arranged links <NUM> are pressed against one another when in the tensioned position (<FIG>) to rigidly fix the plurality of sequentially arranged links <NUM> to one another.

For the embodiment of <FIG> and <FIG>, it will be appreciated that each of the plurality of links <NUM> are designed to result in a specific rigidized shape when the plurality of links <NUM> are moved to the tensioned position. For example, a first link 106A of the plurality of links <NUM> defines a first geometry (i.e., length, curvature, etc.) and a second link 106B of the plurality of links <NUM> defines a second geometry (i.e., link, curvature, etc.). The first geometry is different than the second geometry. In at least certain exemplary embodiments, in order to form the plurality of links <NUM> having specific geometries to facilitate a desired shape of the plurality of links <NUM>, each of the plurality of links <NUM> may be formed through an additive manufacturing process (sometimes also referred to as 3D printing). Such may facilitate the formation of specifically shaped links <NUM> to be fitted within the plurality of links <NUM> of an extension tool <NUM> resulting in a desired shape when moved to the tensioned position, yet still remaining flexible enough to fit through an anticipated environment.

Further, with regard to the plurality of lines <NUM> of the line assembly <NUM>, it will be appreciated that each of these lines <NUM> may be configured as cables, ropes, threads, etc. Accordingly, it will be appreciated that the lines <NUM> are generally flexible (i.e., will not prevent the plurality of sequentially arranged links <NUM> from pivotably moving relative to one another in the slacked position). Further, one or more of the lines <NUM> may be formed of a metal material, such as a steel, tungsten, etc. Alternatively, however, the lines <NUM> may be formed of any other suitable material.

In at least certain exemplary embodiment, it will be appreciated that the extension tool <NUM> depicted in <FIG> and <FIG> may include a tool implement coupled to one of the plurality of links <NUM>. For example, the extension tool <NUM> defines a distal end <NUM>, and the tool implement may be coupled to the link <NUM> at the distal end <NUM>. In certain exemplary embodiment, the tool implement may include one or more sensors, cameras, or both, and additionally, or alternatively, may include one or more drills, laser tools, welding implements, rotatable implement (such as a Phillips head screwdriver bit, a flat head screwdriver bit, a Torx bit, Allen bit, Pozidrive, or the like), etc. In such a manner, the extension tool <NUM> may facilitate performing mechanical operations on a part at a remote location, or along an obscure vector within an environment (e.g., along a non-linear path within the environment) that would otherwise be more difficult.

With one or more of the configurations, the extension tool <NUM> may include a flexible driveshaft extending through an interior of the plurality of links <NUM>, and more specifically, through a tube defined along a length of the plurality of links <NUM> (later described as a first passage).

It will further be appreciated, however, that in other embodiments, the extension tool <NUM> may be configured in any other manner to perform operations at a remote location, or along an obscure vector, within an environment.

Specifically, for the embodiment shown, the extension tool <NUM> is configured such that the plurality of sequentially arranged links <NUM> defines a passage therethrough when the plurality of sequentially arranged links <NUM> are in the tensioned position (<FIG>).

More specifically, for the embodiment shown, the extension tool <NUM> is configured such that the plurality of sequentially arranged links <NUM> defines a passage therethrough when the plurality of sequentially arranged links <NUM> are in the tensioned position (<FIG>). For the embodiment depicted, the passage is a fluid flow passage. However, in other embodiments, the passage may not be configured to provide a fluid flow and instead may be configured to, e.g., act as a guide tube for a tool.

It will be appreciated, that as used herein, the term "fluid flow passage" refers to any substantially continuous passage through the plurality of sequentially arranged links <NUM> when the plurality of sequentially arranged links <NUM> are in the tensioned position, capable of providing a gas or liquid flow to a location proximate the distal end <NUM> of the plurality of sequentially arranged links <NUM>, or extracting a gas or liquid flow from a location proximate the distal end <NUM> of the plurality of sequentially arranged links <NUM>.

More specifically, referring particular to <FIG>, the plurality of sequentially arranged links <NUM> together define a first passage and a second passage, the second passage being separate from the first passage when the plurality of sequentially arranged links <NUM> are in the tensioned position. More specifically, still, for the embodiment shown, the first passage is a first fluid flow passage <NUM> and the second passage is a second fluid flow passage <NUM>. However, as noted above, in other embodiments the first and/or second passage may not be configured to provide a fluid flow and instead may be configured to, e.g., act as a guide tube for a tool.

The second fluid flow passage <NUM> is separate from the first fluid flow passage <NUM> when the plurality of sequentially arranged links <NUM> are in the tensioned position. In such a manner, separate fluids may flow through the respective first and second fluid flow passages <NUM>, <NUM>. As will be appreciated from the description herein, and particularly from the embodiments described below, in at least certain exemplary embodiments, including the embodiment of <FIG>, the first fluid flow passage <NUM> is an inner fluid flow passage and the second fluid flow passage <NUM> is an outer fluid flow passage. In such a manner, the inner fluid flow passage is positioned inward of the outer fluid flow passage, with the outer fluid flow passage substantially completely surrounding the inner fluid flow passage. As such, the outer fluid flow passage may define a generally annular shape surrounding the inner fluid flow passage.

However, in other exemplary embodiments, the first and second fluid flow passages <NUM>, <NUM> may be arranged in any other suitable manner. For example, in other embodiments, the first and second fluid flow passages <NUM>, <NUM> may instead run parallel and adjacent to one another, but may not be arranged concentrically (e.g., one of the first or second fluid flow passages <NUM>, <NUM> extending along one side of the plurality of links <NUM> and the other of the first or second fluid flow passages <NUM>, <NUM> extending along another side of the plurality of links <NUM>).

Referring still to the exemplary embodiment of <FIG>, the second fluid flow passage <NUM> is substantially fluidly isolated from the first fluid flow passage <NUM> when the plurality of sequentially arranged links <NUM> are in the tensioned position. As used herein, the term "substantially fluidly isolated" refers to less than <NUM>% of a fluid provided to a respective one of the first fluid flow passage <NUM> or second fluid flow passage <NUM> transferring to the other of the first fluid flow passage <NUM> or second fluid flow passage <NUM> during normal operations, including the operations described herein.

Referring still particularly to <FIG>, it will be appreciated that the extension tool <NUM> further includes features for providing one or more fluid flows through the first fluid flow passage <NUM>, the second fluid flow passage <NUM>, or both. For example, for the embodiment of <FIG>, the extension tool <NUM> further includes a first fluid flow device <NUM> fluidly coupled to the first fluid flow passage <NUM>, the second fluid flow passage <NUM>, or both.

In particular, for the embodiment of <FIG> the first fluid flow device <NUM> is fluidly coupled to the first fluid flow passage <NUM> through a first conduit <NUM>, and the extension tool <NUM> further includes a second fluid flow device <NUM> fluidly coupled to the second fluid flow passage <NUM> through a second conduit <NUM>. In certain embodiments, such as the embodiment shown, the first fluid flow device <NUM> generally includes a first pressurized fluid source for providing a first pressurized fluid flow <NUM> (shown schematically through conduit <NUM>) through the first fluid flow passage <NUM>. The first pressurized fluid flow <NUM> may be, e.g., a heated gas flow, a pressurized gas flow, a heated liquid flow, a pressurized liquid flow, etc..

Further for the embodiment of <FIG>, the second fluid flow device <NUM> similarly includes a second pressurized fluid source for providing a second pressurized fluid flow <NUM> (shown schematically through conduit <NUM>) through the second fluid flow passage <NUM>. The second pressurized fluid <NUM> flow may include a different fluid flow than the first fluid flow <NUM> (e.g., a different gas, different liquid), may operate at a different temperature and/or pressure, etc..

For example, in certain exemplary embodiments the first pressurized fluid flow <NUM> may be a heated gas flow operating at a first temperature (such as a first initial temperature as measured at a base end of the plurality of links <NUM>) and the second pressurized fluid flow <NUM> may similarly be a heated gas flow operating at a second temperature (such as a second initial temperature as measured at a base end of the plurality of links <NUM>). The second temperature may be less than the first temperature to reduce a thermal gradient on a component on which the first and second pressurized fluid flows <NUM>, <NUM> are directed. Additionally, or alternatively, the second temperature may be set to, e.g., ensure a thermal expansion of the first line 118A and the second line 118B of the line assembly <NUM> matches a thermal expansion of the plurality of links <NUM> during operation, thereby reducing a tension on the first and second lines 118A, 118B.

It will be appreciated, however, that in other exemplary embodiments, the extension tool <NUM> may operate in any other suitable manner. For example, as is depicted in phantom in <FIG>, and other exemplary embodiments, the second pressurized fluid source of the second fluid flow device <NUM> may instead be a fluid pump for urging a second pressurized fluid flow <NUM>' from the second fluid flow passage <NUM> in a direction opposite the first fluid flow <NUM>. With such a configuration, the extension tool <NUM> may, e.g., ensure any leakage of a first pressurized fluid flow <NUM> through the first fluid flow passage <NUM> (e.g., between adjacent links <NUM>) is captured and not leaked into the environment, and/or, may operate to suction up excess of the first pressurized fluid flow <NUM> at the distal end <NUM> of the plurality of sequentially arranged links <NUM>. For example, the first pressurized fluid flow <NUM> may be a flow of oil or other lubrication being provided to a particular location within an environment, and the extension tool <NUM> may operate the second fluid flow passage <NUM> as a vacuum to suction up excess oil/lubrication at the particular location within the environment and further to capture any leakage from the first fluid flow passage <NUM>.

Additionally, or alternatively, the extension tool <NUM> may not include separate fluid flow devices for the first and second fluid flow passages <NUM>, <NUM>. Instead, the first and second fluid flow passages <NUM>, <NUM> may be fed from the same fluid flow source (e.g., the first fluid flow source <NUM>). The fluid provided may be a heated fluid. The result may still be a first fluid flow <NUM> at the distal end <NUM> at a first temperature greater than a second temperature of a second fluid flow <NUM>. Such may result from the second fluid flow effectively insulating the first fluid flow <NUM> and exchanging heat with the environment.

Referring again to both <FIG> and <FIG>, it will be appreciated that the line assembly <NUM> is operable with the plurality of sequentially arranged links <NUM> to move the plurality of sequentially arranged links <NUM> between the slacked position (<FIG>) and tensioned position (<FIG>). Specifically, the first line 118A and second line 118B of the line assembly <NUM> may be fixed to the link <NUM> at the distal end <NUM> of the plurality of sequentially arranged links <NUM>. When the first line 118A and second line 118B of the line assembly <NUM> are tensioned (i.e., an amount of slack is taken out of the first and second lines 118A, 118B), a tension in the first line 118A and second line 118B presses each of the plurality of sequentially arranged links <NUM> against one another, fixing the plurality of sequentially arranged links <NUM> in position to form a substantially rigid extension. Notably, for the embodiment show, the plurality of links <NUM> includes a base link <NUM> fixed to the base <NUM>, allowing the first and second lines 118A, 118B to be pulled tight.

As will be appreciated more fully from the discussion below, it will be appreciated that the first line 118A defines a first displacement when the plurality of sequentially arranged links <NUM> are moved from the slacked position to the tensioned position (i.e., the amount of slack taken out of the first line 118A), and similarly, the second line 118B defines a second displacement when the plurality of sequentially arranged links <NUM> are moved from the slacked position to the tensioned position (i.e., the amount of slack taken out of the second line 118B). More particularly, the first and second displacement may be measured by subtracting a first length <NUM> of the lines 118A, 118B between the plurality of links <NUM> and the root <NUM> (<FIG>) when the links <NUM> are in the slacked position from a second length <NUM> of the lines 118A, 118B between the plurality of links <NUM> and the root <NUM> (<FIG>) when the links <NUM> are in the tensioned position.

For the embodiment shown, the first displacement is substantially equal to the second displacement. For example, in at least certain exemplary embodiments, the first displacement may be within a <NUM>% margin based on a value of the first displacement, or more specifically may be within a <NUM>% margin of the second displacement based on the value of the first displacement.

As will also be appreciated more fully below, the substantially equal displacements of the first line 118A and the second line 118B are accomplished at least in part due to a positioning of a plurality of line guides (see, e.g., <FIG>) within the plurality of sequentially arranged links <NUM>. In particular, the line guides facilitate each pair of adjacent links <NUM> pivotably moving relative to one another about a pivot reference line with the first line 118A and second line 118B positioned along the pivot reference line at a respective end of the link <NUM>. For example, for the embodiment of <FIG> and <FIG>, the plurality of sequentially arranged links <NUM> form a non-linear shape when moved to the tensioned position, and more specifically, define a two-dimensional, nonlinear shape in the plane depicted (i.e., in a plane defined by the lengthwise direction LW and the crosswise direction CW). Each of the adjacent pair of sequentially arranged links <NUM> is configured to pivot about a respective pivot reference line perpendicular to the plane depicted in <FIG>, and the first and second reference lines <NUM> at the respective ends of the respective links <NUM> along the respective pivot reference line. Such is described in more detail below.

Briefly, it will be appreciated that the term "pivot reference line" generally refers to a reference line about which one link most easily pivots relative to another link during normal operation.

Referring now to <FIG> and <FIG>, an extension tool <NUM> in accordance with another exemplary embodiment of the present disclosure is provided. <FIG> depicts the exemplary extension tool <NUM> in a slacked position and <FIG> depicts the exemplary extension tool <NUM> in a tensioned position. The exemplary extension tool <NUM> may be configured in a similar manner as exemplary extension tool <NUM> described above with reference to <FIG> and <FIG>. For example, the exemplary extension tool <NUM> of <FIG> and <FIG> generally includes a plurality of sequentially arranged links <NUM>, as well as a line assembly <NUM> having a first line 118A and a second line 118B operable with the plurality of sequentially arranged links <NUM> to move the plurality of sequentially arranged links <NUM> between the slacked position (<FIG>) and the tensioned position (<FIG>).

As with the embodiment of <FIG> and <FIG>, for the embodiment of <FIG> and <FIG>, the first line 118A defines a first displacement when the plurality of sequentially arranged links <NUM> are moved from the slacked position (<FIG>) and the tensioned position (<FIG>) and the second line 118B defines a second displacement when the plurality of sequentially arranged links <NUM> are moved from the slacked position (<FIG>) and the tensioned position (<FIG>). The first displacement is substantially equal to the second displacement.

As noted above, such may be accomplished at least in part due to a positioning of the lines <NUM> at the ends of the respective links <NUM>. For example, for the embodiment shown, the plurality of sequentially arranged links <NUM> generally includes a first link 106A and a second link 106B spaced from one another when in the slacked position to allow the second link 106B to pivotably move relative to the first link 106A about a pivot reference line <NUM>. The first line 118A and the second line 118B of the line assembly <NUM> are positioned along the pivot reference line <NUM> at an end of the first link 106A proximate to the second link 106B.

More specifically, the first link 106A extends between a first end <NUM> and a second end <NUM>, and similarly, the second link 106B extends between a first end <NUM> (located proximate the second end <NUM> of the first link 106A) and a second end <NUM>. For the embodiment depicted, the plurality of sequentially arranged links <NUM> form a nonlinear shape when moved to the tensioned position, and more specifically, define a three-dimensional, nonlinear shape when moved to the tensioned position (<FIG>).

As such, the first link 106A defines a first pivot reference line 148A at the first end <NUM> of the first link 106A and a second pivot reference line 148B at the second end <NUM> of the first link 106A (or more particularly, the first link 106A defines the second pivot reference line 148B at the second end <NUM> of the first link 106A with the first end <NUM> of the second link 106B). The first pivot reference line 148A is out of plane with the second pivot reference line 148B. More specifically, the exemplary extension tool <NUM> defines an X direction, a Y direction, and a Z direction collectively forming an orthogonal coordinate system. As depicted in <FIG>, the first pivot reference line 148A and second pivot reference line 148B are nonparallel in the X-Y plane, and as shown in callout circles A and B, are similarly nonparallel in the X-Z plane.

Further, referring still to <FIG>, it will be appreciated that the second link 106B also defines pivot reference lines <NUM>. Specifically, as briefly noted above, the second link 106B defines the second pivot reference line 148B at its first end <NUM> along with the second end <NUM> of the first link 106A, and the second link 106B further defines a third pivot line <NUM> at its second end <NUM>. The third pivot line <NUM> is similarly out of plane with the first pivot line <NUM> and the second pivot line <NUM> (see, also, callout Circle C).

Notably, the pivot lines <NUM> refer to an imaginary reference line generally about which one link <NUM> pivots relative to another link <NUM> during normal operations when in the slacked position. The pivot reference lines <NUM> may be set by a shape of the adjacent links <NUM> and gravitational forces when held out in the slacked position, and may in some cases be influenced by the positioning of the first and second lines 118A, 118B.

Further, with the embodiment depicted, the first line 118A and the second line 118B of the line assembly <NUM> are generally arranged along pivot lines <NUM> at a respective end of a respective link <NUM>. As will be shown more clearly in the Figures below, each of the plurality of links <NUM> includes one or more line guides for holding the plurality of lines <NUM> of the line assembly <NUM> in position.

For example, referring to <FIG> and <FIG>, close-up views of the first link 106A are provided. Specifically, <FIG> provides a first side view of the first link 106A and <FIG> provides a second side view of the first link 106A. Notably, the first side view of <FIG> is the same view depicted in <FIG> and <FIG>.

As shown, the first link 106A generally includes a wall <NUM> extending between the first end <NUM> and the second end <NUM>, with the wall <NUM> forming a segment <NUM> of a first line guide <NUM> (<FIG>; depicted in phantom) and a segment <NUM> of a second line guide <NUM> (<FIG>; also depicted in phantom). The first line 118A of the line assembly <NUM> extends through the first line guide <NUM> and the second line 118B of the line assembly <NUM> extends through the second line guide <NUM>. The first line guide <NUM> and the second line guide <NUM> are arranged along the first pivot reference line 148A at the first end <NUM> of the first link 106A, and similarly, the first line guide <NUM> and the second line guide <NUM> are arranged along the second pivot reference line 148B at the second end <NUM> of the first link 106A.

Referring still to <FIG> and <FIG>, it will be appreciated that the segment <NUM> of the first line guide <NUM> through the first link 106A extends in a serpentine path between the first end <NUM> of the first link 106A and second end <NUM> of the first link 106A relative to a geometry of the first link 106A. Notably, as used herein, the term "serpentine path" relative to a geometry of a particular link refers to a path having a shape different than a shape of the link (as may be determined by, e.g., a centerline of the link).

Additionally, the segment <NUM> of the second line guide <NUM> through the first link 106A extends in a serpentine path between the first end <NUM> of the first link 106A and the second end <NUM> of the first link 106A relative to the geometry of the first link 106A. Further, for the embodiment shown, the shape of the segment <NUM> of the first line guide <NUM> through the first link 106A is different than the shape of the segment <NUM> of the second line guide <NUM> through first link 106A.

Further still, it will be appreciated from <FIG> collectively, that the second end <NUM> of the first link 106A defines a first mating geometry and the first end <NUM> of the second link 106B defines a second mating geometry (see, e.g., <FIG>). The second mating geometry is complementary in shape to the first mating geometry to fully constrain the first link 106A relative to the second link 106B when the plurality of sequentially arranged links <NUM> are moved to the tensioned position. In such a manner, the plurality of lines <NUM> of the line assembly <NUM> are not required to align each adjacent link <NUM> relative to one another, and instead are simply utilized for providing a necessary tension between adjacent links <NUM>. Such may prevent or minimize kinks, knots, twists, etc. within the lines <NUM> of the line assembly <NUM> during operation.

For the embodiment depicted, the first mating geometry at the second end <NUM> of the first link 106A includes a pair of concave curves <NUM> alternating with a pair of convex curves <NUM>, and the second mating geometry at the first end <NUM> of the second link 106B similarly includes a pair of convex curves <NUM> alternating with a pair of concave curves <NUM>. Notably, for the embodiment shown, a height of a first of the concave curves <NUM> of the first mating geometry is equal to a height of a first of the convex curves <NUM> of the second mating geometry; a height of a second concave curve <NUM> of the first mating geometry is equal to a height of a second convex curve <NUM> of the second mating geometry; a height of a first convex <NUM> curve of the first mating geometry is equal to a height of a first concave curve <NUM> of the second mating geometry; and a height of a second convex curve <NUM> of the first mating geometry is equal to a height of a second concave curve <NUM> of the second mating geometry.

However, in other embodiments, the extension tool <NUM> may include links <NUM> having any other suitable geometry for mating and constraining adjacent links <NUM> in a tensioned position.

As was noted above, the plurality of sequentially arranged links <NUM> together form a first fluid flow passage <NUM> and a second fluid flow passage <NUM> that are separate from one another when the plurality of sequentially arranged links <NUM> are in a tensioned position.

Referring now to <FIG>, such a configuration is described in greater detail. <FIG> depicts a close-up view of a junction between adjacent links <NUM> of the plurality of links <NUM> of the extension tool <NUM> depicted above in <FIG> and <FIG>, and <FIG> provides a close-up view of one end of one of the links <NUM> of <FIG>.

As shown, a first link 106A in the plurality of sequentially arranged links <NUM> includes a wall <NUM>. More specifically, for the embodiment shown, the first link 106A in the plurality of sequentially arranged links <NUM> includes a first wall 156A and a second wall 156B. The first wall 156A of the first link 106A defines in part a first fluid flow passage <NUM> and the second wall 156B of the first link 106A defines in part a second fluid flow passage <NUM>. For the embodiment shown, the first wall 156A is an inner wall and the second wall 156B is an outer wall. The outer wall substantially completely surrounds the inner wall <NUM>, such that the second fluid flow passage <NUM> is a generally annular passage surrounding the first fluid flow passage <NUM>.

For the embodiment depicted, the second wall 156B is coupled to the first wall 156A through one or more point contacts <NUM> (see <FIG>), such that the first and second wall 156A, 156B are not continuously connected along a length of each respective link <NUM>. Specifically, for the embodiment shown, the one or more point contacts <NUM> are located at the ends of the links <NUM> (e.g., as first and second ends of each link <NUM>). It will be appreciated that as used herein, the term "point contact" with reference to the connection between the first and second wall 156A, 156B of a respective link <NUM> refers to a connection that does not extend significantly along a length of the respective link, such as less than about <NUM>% along a length of a respective link <NUM>. For example, in certain exemplary embodiments, the point contacts <NUM> may extend less than about <NUM>% along a length of a respective link <NUM>, such as less than about <NUM>% along a length of a respective link <NUM>, such as less than about <NUM>% along a length of a respective link <NUM>. This embodiment represents an innovative solution to limit thermal conduction path from outer wall 156B to inner wall 156A by providing a narrow connection element (i.e., point contacts <NUM>).

Further, as noted above, the plurality of sequentially arranged links <NUM> include a plurality of line guides for the plurality of lines <NUM> of the line assembly <NUM>. In particular, for the embodiment shown, the line assembly <NUM> includes a first line 118A and a second line 118B, and the plurality of sequentially arranged links <NUM> similarly includes a first line guide <NUM> and a second line guide <NUM>. Each link <NUM> includes a segment <NUM> of the first line guide <NUM> and segment <NUM> of the second line guide <NUM>. For the embodiment shown, the line guides <NUM>, <NUM> are positioned on an interior of the second wall 156B of each link <NUM> of the plurality of links <NUM>.

It will be appreciated, however, that in other embodiments, the line guides may instead be located elsewhere, such as on an outside of the second wall 156B, on an outside of the first wall 156A, on an interior of the first wall 156A, or some combination thereof.

It will further be appreciated from the discussion above that for the embodiments depicted and described, adjacent links <NUM> are sealed together by including mating geometries at their respective ends that are complementary in shape with the mating geometries of the adjacent links. The walls <NUM> of the links <NUM> are pressed together and the contact pressure applied by the lines <NUM> form a contact seal therebetween to provide a seal between such links <NUM>.

However, in certain embodiments, it may be desirable to provide a seal between adjacent links to provide a more air-tight, liquid-tight seal between adjacent links <NUM> (and therefore a more air-tight or liquid-tight fluid flow passage). For example, referring to <FIG>, three exemplary seal assemblies between a wall <NUM> of a first link 106A and a wall <NUM> of a second link 106B are provided.

For the embodiment of <FIG>, the seal assembly includes a gasket <NUM>. The gasket <NUM> may be formed of any suitable material for the anticipated operations. For example, the gasket may be formed of an elastomeric material, a relatively flexible metal material, etc. The gasket <NUM> may be fixedly coupled to one of the wall <NUM> of the first link 106A or the wall <NUM> of the second link 106B.

For the embodiment of <FIG>, the seal includes a spline <NUM>. For this embodiment, the wall <NUM> of the first link 106A includes a groove <NUM>, with the spline positioned therein. Similarly, the wall <NUM> of the second link 106B includes a groove <NUM>. When the first link <NUM> a and the second link 106B are moved to the tensioned position, the spline <NUM> is further positioned within the groove <NUM> of the second link 106B.

For the embodiment of <FIG>, the seal includes a complementary mating geometry across a thickness of the wall <NUM> of the first link 106A and the wall <NUM> of the second link 106B. For example, for the embodiment shown, the <NUM> of the first link 106A includes a raised knob <NUM>, and the wall <NUM> of the second link 106B includes a complementary groove <NUM>.

It will be appreciated, however, that in other embodiments, any other suitable configuration may be provided for forming a seal between adjacent links <NUM>.

Further, referring now to <FIG>, a close-up, schematic view of a link <NUM> of a plurality of links <NUM> of an extension tool <NUM> is provided at a distal end <NUM> of the plurality of links <NUM> in accordance with an exemplary embodiment of the present disclosure. The link <NUM> depicted may be configured in accordance with one or more of the exemplary embodiments described above, or alternatively may be configured in accordance with any other suitable embodiment.

For the embodiment shown, the extension tool <NUM> includes a plurality of lines <NUM> extending along a length thereof, and more specifically includes a first line 118A and a second line 118B. Notably, however, for the embodiment shown, the first and second lines 118A, 118B are integral with one another at the distal end <NUM>, such that the first line 118A meets the second line 118B at the distal end <NUM>. In such a manner, the first and second lines 118A, 118B may in fact be a single line looped at the distal end <NUM>. For this embodiment the lines <NUM> includes a transition portion <NUM> at the distal end <NUM> where the first line 118A loops around and transition into the second line 118B.

With such a configuration, in order to ensure both the first and second lines 118A, 118B do not completely pull out of the plurality of links <NUM> in the event of a failure of one of the first or second lines 118A, 118B, the extension tool <NUM> includes an attachment feature <NUM> coupled to the first line 118A, the second line <NUM>, or both. More specifically, for the embodiment shown, the extension tool <NUM> includes the attachment feature <NUM> coupled to the transition portion <NUM> of the first and second lines 118A, 118B.

For the embodiment depicted, the attachment feature <NUM> defines a greater width <NUM> than the first and second lines 118A, 118B and is fixedly coupled to the transition portion <NUM> of the line <NUM>. For example, the attachment feature <NUM> may be a crimp member, crimped onto the transition portion <NUM> of the lines <NUM>. Alternatively, the attachment feature <NUM> may include a base with a screw or bolt extending to the line(s) <NUM> to fix the attachment feature <NUM> to the line(s) <NUM>, a base welded, glued, epoxied, etc. to the line(s) <NUM>, etc. In other embodiments, other configurations may be provided as well. Further, although a single attachment feature <NUM> is depicted, in other embodiments, multiple attachment features <NUM> may be provided.

More specifically, for the embodiment shown, the link <NUM> at the distal end includes support surfaces <NUM> to support the transition portion <NUM> of the line <NUM>, such that a load on the attachment feature <NUM> may be minimized. In such a manner, the attachment feature <NUM> may effectively float between the support surfaces <NUM>. However, in the event of a failure of one of the first or second lines 118A, 118B, the attachment feature <NUM> may be configured to abut against a respective line guide <NUM>, <NUM> to prevent the line <NUM> remaining intact from sliding therethrough, allowing for the line <NUM> remaining intact to be used to remove the plurality of links <NUM> from the environment.

Referring now to <FIG>, another close-up, schematic view of a link <NUM> of a plurality of links <NUM> of an extension tool <NUM> is provided at a distal end <NUM> of the plurality of links <NUM> in accordance with an exemplary embodiment of the present disclosure. The link <NUM> depicted in <FIG> may be configured in a similar manner to the exemplary link <NUM> described above with respect to <FIG>.

For example, the exemplary extension tool <NUM> depicted includes a first line 118A and a second line <NUM> formed integrally at a transition portion <NUM> at the distal end <NUM>. The extension tool <NUM> further includes an attachment member <NUM>. For the embodiment depicted, the attachment member <NUM> is attached to the first line 118A at the distal end <NUM>. Notably, the link <NUM> at the distal end <NUM> defines an opening <NUM>, with the first line 118A extending across the opening <NUM> and the attachment member <NUM> located within the opening <NUM>. The opening defines a first shoulder <NUM> where the first line 118A enters across the opening <NUM> and a second shoulder <NUM> where the first line 118A exits across the opening <NUM>. The attachment member <NUM> is positioned between the first and second shoulders <NUM>, <NUM>, without touching the first and second shoulders <NUM>, <NUM> during normal operation.

In such a manner, the attachment member <NUM> is not under any significant load during normal operations (e.g., less than twenty-five percent of the total load on the first line 118A). However, in the event of a failure of the first line 118A or the second line 118B, the attachment member <NUM> may abut against a first shoulder <NUM> or a second shoulder <NUM> to prevent the line <NUM> remaining intact from sliding through the respective line guides <NUM>, <NUM>, allowing for the line <NUM> remaining intact to be used to remove the plurality of links <NUM> from the environment.

Further, referring now to <FIG>, one exemplary application of the various extension tools <NUM> of the present disclosure will be described. Specifically, <FIG> depicts an extension tool <NUM> in accordance with an exemplary embodiment of the present disclosure being utilized to navigate through a nonlinear path within an environment, which for the embodiment shown is a gas turbine engine <NUM>.

Specifically, for the embodiment of <FIG>, the gas turbine engine <NUM> is configured as a turbofan engine. The turbofan engine generally includes a fan section <NUM> and a turbomachine <NUM>.

The turbomachine <NUM> generally includes a compressor section having a low pressure ("LP") compressor <NUM> and a high pressure ("HP") compressor <NUM>; a combustion section <NUM>; a turbine section including an HP turbine <NUM> and an LP turbine <NUM>; and an exhaust section (not shown). The compressor section, combustion section <NUM>, turbine section, and exhaust section are each arranged in serial flow order. The LP compressor <NUM> and LP turbine <NUM> are coupled through an LP shaft <NUM>, and similarly, the HP compressor <NUM> and HP turbine <NUM> are coupled to an HP shaft <NUM>. Additionally, the turbomachine <NUM> includes a casing 221enclosing at least in part the above-noted components of the turbomachine <NUM>. Further, for the embodiment shown the fan section <NUM> includes a fan having a plurality of fan blades <NUM>, with the fan and plurality of fan blades <NUM> being driven by the LP shaft <NUM>.

In the callout Circle A, a close-up, schematic view of the combustion section <NUM> of the exemplary gas turbine engine <NUM> is provided. The combustion section <NUM> generally includes an inner liner <NUM> and an outer liner <NUM>, together defining at least in part a combustion chamber <NUM>. The combustion section <NUM> further includes a fuel nozzle <NUM> configured to provide, e.g., a mixture of fuel and compressed air to be combusted within the combustion chamber <NUM> during operation of the gas turbine engine <NUM>. An igniter (not shown) may be positioned within an igniter hole <NUM> of the outer liner <NUM> for igniting the fuel and compressed air mixture.

After operating for an amount of time, an undesirable amount of coke buildup may form on or within the fuel nozzle <NUM>. For example, during a shutdown of the gas turbine engine <NUM>, fuel may remain within the fuel nozzle <NUM> and residual heat within the gas turbine engine <NUM> may cause the remaining fuel to coke. During, e.g., a maintenance interval, the extension tool <NUM> may be utilized to remove the buildup of coke on or within the fuel nozzle <NUM>.

The exemplary extension tool <NUM> depicted may be configured in accordance with one or more of the exemplary embodiments described above with reference to <FIG>. For example, the exemplary extension tool may generally include a plurality of links <NUM> movable to a tensioned position (shown) having a nonlinear, two-dimensional or three-dimensional shape when in the tensioned position. Notably, the ability to additionally be moved to a slacked position may assist with moving the plurality of links <NUM> through the gas turbine engine <NUM> environment and through the igniter hole <NUM>.

Further, the plurality of links <NUM> may together define a first fluid flow passage <NUM> (not shown) and a second fluid flow passage <NUM> (not shown). The extension tool <NUM> may be configured to provide a first gas flow <NUM> through the first fluid flow passage <NUM> and a second gas flow <NUM> through the second fluid flow passage <NUM>. In order to remove the buildup of coke on or within the fuel nozzle <NUM>, the first gas flow <NUM> may be a heated and pressurized gas flow defining a first operational temperature, and the second gas flow <NUM> may also be a heated and pressurized gas flow defining a second operational temperature. The first operational temperature may be sufficient to burn off the coke within the fuel nozzle <NUM>. The second operational temperature may be less than the first operational temperature for heating to a lesser degree the area surrounding the coke buildup being burnt off to lessen a temperature gradient across the component.

Of course, in other embodiments, the extension tool <NUM> may be utilized for a myriad of different operations and functions.

Referring now to <FIG>, a method <NUM> is provided for operating an extension tool within an environment. The method may utilize one or more of the exemplary extension tools described above with reference to <FIG>. Accordingly, for example, the extension tool may generally include a plurality of sequentially arranged links together defining a first fluid flow passage and a second fluid flow passage. However, in other embodiments, any other suitable extension tool may be utilized.

The method <NUM> generally includes at (<NUM>) providing a first fluid flow through a first fluid flow passage, and at (<NUM>) providing a second fluid flow through a second fluid flow passage. The second fluid flow passage is separate from the first fluid flow passage when the plurality of sequentially arranged links are joined together.

For example, in certain exemplary embodiments, the extension tool may be configured similar to the embodiments described above, such that the plurality of sequentially arranged links are movable between a slacked position and a tensioned position. With such an exemplary embodiment, the second fluid flow passage is separate from the first fluid flow passage when the plurality of sequentially arranged links are joined together by being moved to the tensioned position. Additionally, or alternatively, in certain exemplary embodiments, the second fluid flow passage may be substantially fluidly isolated from the first fluid flow passage when the plurality of sequentially arranged links are joined together by being moved to the tensioned position.

Referring still to <FIG>, for the exemplary method <NUM> depicted, the first fluid flow is a first heated fluid flow and the second fluid flow is a second heated fluid flow. With such an exemplary embodiment, providing the first fluid flow through the first fluid flow passage at (<NUM>) includes at (<NUM>) providing the first heated fluid flow through the first fluid flow passage at a first starting temperature (i.e., a temperature of the fluid flow as it enters the first fluid flow passage), and providing the second fluid flow through the second fluid flow passage at (<NUM>) includes at (<NUM>) providing the second heated fluid flow through the second fluid flow passage at a second starting temperature. The first starting temperature may be greater than the second starting temperature, such as at least about <NUM>% greater, such as at least about <NUM>% greater, such as at least about <NUM>% greater, such as at least about <NUM>% greater, such as at least about <NUM>% greater, such as up to <NUM>% greater, such as up to <NUM>% greater, such as up to <NUM>% greater, such as up to <NUM>% greater.

Further, with the exemplary aspect of the method <NUM> depicted in <FIG>, providing the first fluid flow through the first fluid flow passage at (<NUM>) includes at (<NUM>) providing a first pressurized fluid flow through the first fluid flow passage in a first direction. The first direction may generally be from a base of the plurality of sequentially arranged links towards a distal end of the plurality of sequentially arranged links. Further, providing the second fluid flow through the second fluid flow passage at (<NUM>) includes at (<NUM>) providing a second pressurized fluid flow through the second fluid flow passage in the same direction as the first pressurized fluid flow (i.e., the first direction).

It will be appreciated, however, that in other exemplary aspects, providing the second fluid flow through the second fluid flow passage at (<NUM>) may alternatively include, as is depicted in phantom at (<NUM>) providing the second fluid flow through the second fluid flow passage in an opposite direction than the first pressurized fluid flow (e.g., a second direction, such as a direction extending generally from a distal end of the plurality of sequentially arranged links towards a base of the plurality of sequentially arranged links). With such an exemplary aspect, the extension tool may effectively utilize the second fluid flow passage as a vacuum.

Referring still to the exemplary aspect of the method <NUM> depicted, for the exemplary aspect depicted, the method <NUM> is configured to reduce undue stress on a plurality of lines operable with the plurality of links. For example, the plurality of lines may generally extend through a plurality of line guides positioned within, or thermally coupled to the second fluid flow passage. With such an exemplary aspect, providing the second fluid flow through the second fluid flow passage at (<NUM>) may further include at (<NUM>) providing the second heated flow at a second starting temperature such that the plurality of lines of the line assembly thermally expand substantially the same amount as the plurality of sequentially arranged links. For example, the plurality of lines may be formed of a metal, such as tungsten or a tungsten alloy, having a different coefficient of thermal expansion than a material forming the plurality of links. The heated fluid flow through the first fluid flow passage may define a starting temperature necessary for performing the desired operations (e.g., burning off coke from a fuel nozzle). The heated fluid flow through the second fluid flow passage may define a different starting temperature designed to thermally expand the plurality of lines substantially the same amount as expected thermal expansion of the plurality of sequentially arranged links due to the starting temperature the first fluid flow through the first fluid flow passage.

Although not depicted, additional selectively flexible tools may be utilized in additional exemplary aspects of the present disclosure.

Claim 1:
An extension tool (<NUM>) for use in a gas turbine engine, comprising:
a plurality of sequentially arranged links (<NUM>) moveable to a first position, the plurality of sequentially arranged links (<NUM>) rigidly fixed to one another in the first position, the plurality of sequentially arranged links (<NUM>) defining a first passage (<NUM>) and a second passage (<NUM>), the second passage (<NUM>) being separate from the first passage (<NUM>) when the plurality of sequentially arranged links (<NUM>) are rigidly fixed to one another,
wherein a first link (<NUM>) of the plurality of sequentially arranged links (<NUM>) includes a first wall (156A) and a second wall (156B), wherein the first wall (156A) of the first link (<NUM>) defines in part the first passage (<NUM>), wherein the second wall (156B) of the first link (<NUM>) defines in part the second passage (<NUM>), and wherein the second wall (156B) is coupled to the first wall (156A) through one or more point contacts (<NUM>), characterized in that:
the first wall (156A) is an inner wall,
the second wall (156B) is an outer wall, and
the outer wall (156B) substantially completely surrounds the inner wall (156A) such that the second passage (<NUM>) is a generally annular passage surrounding the first passage (<NUM>).