Patent Description:
Inspection of gas turbine engines for maintenance or repairs may frequently require inspection of engine internal components with the aid of a borescope. Borescope plugs may be installed in multiple locations within the engine to permit borescope access once the borescope plug is removed (see, e.g., <FIG>). The location of borescope plugs, however, may be inconvenient to technicians seeking to remove or install the plugs. In some cases, removal or installation of the borescope plug may be a "blind operation" (i.e., the technician can physically reach the borescope plug but, based on the plugs location, cannot visually observe the plug during the removal or installation).

The above orientation of borescope plugs within gas turbine engines can make maintenance and repairs of engines more difficult because of the threat of lost borescope plugs. For example, a technician attempting to blindly remove a borescope plug may inadvertently drop the plug and lose it inside of the air stream ducts or housing of the engine. Attempts to recover a lost borescope plug can result in reduced aircraft operational time and increased man-hours required for maintenance. More importantly, lost borescope plugs that are not recovered may result in extensive damage to the engine if the engine is subsequently returned to service with the borescope plug unsecured.

Examples of borescope systems comprising a borescope plug port, a borescope plug and a borescope tool are disclosed in patent applications <CIT>, <CIT> and <CIT>.

According to an aspect of the present invention, there is provided a borescope plug system as claimed in claim <NUM> and a method for operating a borescope plug as claimed in claim <NUM>. Various embodiments are set out in the dependent claims.

The present invention, and all its aspects, embodiments and advantages associated therewith will become more readily apparent in view of the detailed description provided below, including the accompanying drawings.

It is noted that various connections are set forth between elements in the following description and in the drawings. It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. It is further noted that various method or process steps for embodiments of the present disclosure are described in the following description and drawings. The description may present the method and/or process steps as a particular sequence. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the description should not be construed as a limitation.

Referring to <FIG>, a generalized illustration of an aircraft gas turbine engine including borescope plugs is shown. A gas turbine engine may include one or more borescope plug ports to facilitate inspection of gas turbine engine internal components using a borescope. Each of the borescope plug ports may be configured for receipt of a borescope plug configured to seal the respective borescope plug port. As will be discussed in greater detail, a borescope plug of a respective borescope plug port may be removed to facilitate inspection of gas turbine engine internal components by a technician. A borescope plug, such as borescope plug <NUM> as depicted in <FIG>, is configured to be securely engaged within a borescope plug port, such as borescope plug port <NUM> as depicted in <FIG>. The borescope plug <NUM> may be secured within the borescope plug port <NUM> using, for example, complementary mating engagement with threads formed in the borescope plug port <NUM> or, alternatively, lugs or lug-receiving slots formed in the borescope plug <NUM> for twist-lock engagement with corresponding lugs or slots formed in a complimentary borescope plug port <NUM>. Any known form of plug/port retention mechanisms may be utilized in connection with the borescope plug <NUM> and borescope plug port <NUM>.

Referring to <FIG>, an exemplary guiding sleeve <NUM> according to aspects of the present disclosure is shown. The guiding sleeve <NUM> includes a body <NUM> having a first sleeve end 202E1, a second sleeve end 202E2, and an internal passage <NUM>. The internal passage <NUM> extends between the first sleeve end 202E1 and the second sleeve end 202E2 along a longitudinally extending centerline 202CL. The body <NUM> may have, for example, a substantially cylindrical shape. The guiding sleeve <NUM> is configured to engage an adapter <NUM> of the borescope plug port <NUM> so as to guide a borescope plug <NUM> to or from the borescope plug port <NUM> during a respective installation or removal of the borescope plug <NUM> from the borescope plug port <NUM>. While the exemplary guiding sleeve <NUM>, as shown in <FIG>, is described with respect to use in aircraft gas turbine engines, the guiding sleeve <NUM> is not limited to use in aircraft and may be used with other engine types and configurations in other categories of vehicles. Furthermore, the guiding sleeve <NUM> may be used to facilitate borescope plug installation and removal in non-vehicle machinery (e.g., a turbine generator).

As can be seen in <FIG>, the first sleeve end 202E1 of the guiding sleeve <NUM> is configured to engage the adapter <NUM> of the borescope plug port <NUM> so as to provide secure alignment between the guiding sleeve <NUM> and the borescope plug port <NUM> while permitting access to the borescope plug <NUM> (not shown) of the borescope plug port <NUM> via the internal passage <NUM> of the guiding sleeve <NUM>. Proper engagement between the guiding sleeve <NUM> and the borescope plug port <NUM> may be accomplished by, for example, twist-lock engagement between one or more slots 202E1S of the first sleeve end 202E1 and one or more pins 304P of the adapter <NUM>. In other embodiments, proper engagement between the first sleeve end 202E1 and the adapter <NUM> may be accomplished by any suitable method, such as threaded engagement. In some embodiments, the length and/or width of the guiding sleeve <NUM> may vary depending on the characteristics of the relevant machinery (e.g., the gas turbine engine), for example, the size of the borescope plug <NUM> and the distance to the borescope plug <NUM> from a technician's access point. The guiding sleeve <NUM> may be made from any sufficiently rigid material, such as metal or plastic, to ensure proper engagement with the adapter <NUM> and access to the borescope plug <NUM> via the internal passage <NUM> of the guiding sleeve <NUM>. In some embodiments, the guiding sleeve <NUM> may be made from a plurality of materials. For example, the first sleeve end 202E1 may be made from metal to facilitate secure engagement with the adapter <NUM> while the body <NUM> of the guiding sleeve <NUM> may be made from a second material, such as plastic. In still other embodiments, the guiding sleeve <NUM> may include both rigid and non-rigid materials. For example, the first sleeve end 202E1 may be made from metal to facilitate secure engagement with the adapter <NUM> while the body <NUM> of the guiding sleeve <NUM> may be made from a second non-rigid material, such as fabric or flexible plastic hose.

As can be seen in <FIG>, engagement of the guiding sleeve <NUM> with the borescope plug port <NUM> may facilitate operation of the borescope plug <NUM> (not shown) by a tool, such as driver <NUM>, via the internal passage <NUM> of the guiding sleeve <NUM>. Driver <NUM> includes a first driver end 104E1 (not shown, substantially similar to 404E1 as shown in <FIG>) and a second driver end 104E2. Additionally, driver <NUM> may be a standard square driver, or any other driver configured to install or remove a borescope plug <NUM>. As will be discussed in greater detail, other tools may be used for installation and removal of the borescope plug <NUM>. The alignment of the guiding sleeve <NUM> with the borescope plug port <NUM>, as shown in <FIG>, creates a secure path for the borescope plug <NUM> during installation or removal from the borescope plug port <NUM>. For example, any borescope plug <NUM> inadvertently dropped from a tool, such as driver <NUM>, will be contained in or directed through the guiding sleeve <NUM>, depending on the orientation of the guiding sleeve <NUM> (e.g., vertical, horizontal, etc.). The alignment of the guiding sleeve <NUM> with the borescope plug port <NUM> may also facilitate engagement between the driver <NUM> and the borescope plug <NUM> by directing the driver <NUM> towards the borescope plug <NUM> (e.g., a technician attempting to blindly remove a borescope plug <NUM>).

Still referring to <FIG>, the following non-limiting method is provided to illustrate how the guiding sleeve <NUM> according to aspects of the present disclosure may facilitate borescope plug <NUM> installation and removal. A technician may direct the guiding sleeve <NUM> towards the borescope plug port aligning the one or more slots 202E1S of the first sleeve end 202E1 with the one or more pins 304P of the adapter <NUM>. The guiding sleeve <NUM> is engaged with the borescope plug port <NUM> by twisting the guiding sleeve <NUM>, in direction R3 for example (i.e., counter-clockwise), to establish twist-lock engagement between the first sleeve end 202E1 and the adapter <NUM>. A tool, such as driver <NUM>, is inserted into the internal passage <NUM> of the guiding sleeve <NUM> to engage the borescope plug <NUM>, such as by engaging an interior surface 302I (not shown) of the borescope plug <NUM>. Driver <NUM> is rotated clockwise or counter-clockwise as necessary to install or remove the borescope plug <NUM>. The driver <NUM> is removed from the internal passage <NUM> of the guiding sleeve <NUM> along with the borescope plug <NUM> (if removing the borescope plug). The guiding sleeve <NUM> is then removed from the borescope plug port using a twist motion in a direction opposite that of the installation, in direction R4 for example (i.e., clockwise).

Referring now to <FIG> and <FIG>, an exemplary borescope plug tool <NUM> according to aspects of the present disclosure is illustrated. The borescope plug tool <NUM> generally includes a housing <NUM>, a driver <NUM>, and a spring <NUM>. As will be discussed in greater detail, in some embodiments, the borescope plug tool <NUM> and the guiding sleeve <NUM> may provide a common interface to effect installation or removal of a borescope plug <NUM> from a borescope plug port <NUM>. In other embodiments, the borescope plug tool <NUM> may be used independent of the guiding sleeve <NUM> to effect installation or removal of a borescope plug <NUM> from a borescope plug port <NUM>.

The housing <NUM> includes a first housing end 102E1, a second housing end 102E2, and a longitudinally extending centerline 102CL extending between the first housing end 102E1 and the second housing end 102E2. The driver <NUM> includes a first driver end 404E1 and a second driver end 404E2. Driver <NUM> is disposed at least partially within the housing <NUM> along the longitudinally extending centerline 102CL, with the first driver end 404E1 and the second driver end 404E2 having an orientation corresponding to the respective first housing end 102E1 and second housing end 102E2. Spring <NUM> is disposed within the housing <NUM> and couples the housing <NUM> to the driver <NUM>. The driver <NUM> is configured to move within the housing <NUM> along the longitudinally extending centerline 102CL to engage the borescope plug <NUM> of the borescope plug port <NUM>, such as by engaging the first driver end 404E1 with an interior surface 302I of the borescope plug <NUM>. For example, the second driver end 404E2 of the driver <NUM> may be pulled in direction D, against a force of the spring <NUM>, into a retracted position (see <FIG>) to facilitate engagement between the borescope plug tool <NUM> and the borescope plug <NUM>. When the driver <NUM> is released, the force of the spring <NUM> will return the driver <NUM> to its nominal position (see <FIG>). Once the driver is engaged with the borescope plug <NUM>, rotation of the driver <NUM> in direction R1, R2 about the longitudinally extending centerline 102CL effects installation or removal of the borescope plug <NUM> from the borescope plug port <NUM>.

According to the invention, the first housing end 102E1 is configured to engage the borescope plug <NUM>, such as by engaging an exterior surface 302E, to secure the borescope plug <NUM> to the borescope plug tool <NUM>. Proper engagement between the first housing end 102E1 of the housing <NUM> and the borescope plug <NUM> is accomplished by twist-lock engagement between one or more slots 102E1S of the first housing end 102E1 and one or more pins 302EP of the borescope plug <NUM>. In other examples outside the scope of the claimed invention, proper engagement between the first housing end 102E1 and the borescope plug <NUM> may be accomplished by any suitable method, such as threaded engagement. Engagement of the borescope plug <NUM> to the borescope plug tool <NUM> ensures the borescope plug <NUM> is secured (i.e., prevented from being dropped) as the borescope plug <NUM> is in the process of being inserted or removed from the borescope plug port <NUM>. In some embodiments, one or both of the first housing end 102E1 and the second housing end 102E2 are removable from the housing <NUM>. One or both of the first housing end 102E1 and the second housing end 102E2 may be coupled to the housing by, for example, threaded engagement or any other suitable method. Removal of one or both of the first housing end 102E1 and the second housing end 102E2 may facilitate multiple configurations of the borescope plug tool <NUM>. For example, the second housing end 102E2 may be removed to allow an alternative driver (e.g., one having a different sized or shaped engagement surface), other than driver <NUM>, to be installed in the borescope plug tool <NUM>.

As discussed above, the driver <NUM> may engage the borescope plug <NUM> when released from the retracted position to the nominal position within the housing <NUM>. As with driver <NUM>, driver <NUM> may be a standard square driver, or any other driver configured to install or remove a borescope plug <NUM>. In some embodiments, the driver <NUM>, <NUM> may include at least one spring-loaded ball <NUM> disposed on the first driver end 104E1, 404E1 (see <FIG>). The at least one spring-loaded ball and a corresponding at least one recess 302F, disposed on the interior surface 302I of the borescope plug <NUM> (see <FIG>) may operate together to provide more secure engagement between the first driver end 104E1, 404E1 and the borescope plug <NUM>.

In some embodiments, the housing <NUM> may include at least one guide aperture <NUM> and the driver <NUM> may include a respective at least one guide pin <NUM> located within the at least one guide aperture <NUM> and configured to travel longitudinally within the at least one guide aperture <NUM>. The at least one guide pin <NUM> may be disposed within a respective at least one pin aperture <NUM> extending through the driver <NUM> in a radial direction with respect to the longitudinally extending centerline 102CL (see <FIG>). The orientation of the at least one guide pin <NUM> within the respective at least one guide aperture <NUM> substantially prevents relative motion between the housing <NUM> and the driver <NUM> with respect to the longitudinally extending centerline 102CL. Thus, rotation of the driver <NUM> in direction R1, R2 about the longitudinally extending centerline 102CL will effect a similar rotation of the housing <NUM> about the longitudinally extending centerline 102CL, and vice versa.

This alignment between the housing <NUM> and the driver <NUM> facilitates engagement of the housing <NUM> with the borescope plug <NUM> when removing the borescope plug <NUM> (i.e., the rotational motion of the driver <NUM> required to remove the borescope plug <NUM> is the same rotational motion of the housing <NUM> required to engage and secure the borescope plug <NUM>). The at least one guide aperture <NUM> and respective at least one guide pin <NUM> facilitate proper engagement of the driver <NUM> with the borescope plug <NUM> by providing the technician with visual and/or haptic feedback of the driver <NUM> position. For example, when the driver <NUM> is properly engaged with the borescope plug <NUM>, the at least one guide pin <NUM> may be oriented at a substantially forward-most (i.e., towards the borescope plug <NUM>) longitudinal position within the respective at least one guide aperture <NUM>. Additionally, in some embodiments, one of the at least one guide pins <NUM> may be in communication with the spring <NUM> so as to provide compressive force to the spring <NUM> when the driver <NUM> is pulled in direction D.

Referring to <FIG> and <FIG>, the following non-limiting method is provided to illustrate how the borescope plug tool <NUM> according to aspects of the present disclosure may facilitate borescope plug <NUM> installation and removal. To remove a borescope plug <NUM> from a borescope plug port <NUM>, a technician may direct the borescope plug tool <NUM> towards the borescope plug <NUM> and align the one or more slots 102E1S of the first housing end 102E1 with the one or more pins 302EP of the borescope plug <NUM> while pulling the driver <NUM> in direction D into a retracted position against the force of the spring <NUM> (see <FIG>). As will be apparent to one of ordinary skill in the art, during alignment of the first housing end 102E1 with the borescope plug <NUM>, misalignment between the borescope plug <NUM> and the first driver end 404E1 may push the driver <NUM> into the retracted position, thus, it may be unnecessary for the technician to pull the driver <NUM> in direction D. While driver <NUM> is in a retracted position, the housing <NUM> is engaged with the borescope plug <NUM> by rotating the housing <NUM> or the driver <NUM>, in direction R2 for example (i.e., counter-clockwise), to establish twist-lock engagement between the first housing end 102E1 and the exterior surface 302E of the borescope plug <NUM>. Driver <NUM> is then released, causing the spring <NUM> force to return the driver <NUM> to the nominal position, thereby engaging the first driver end 104E1 with the interior surface 302I of the borescope plug <NUM> (see <FIG>). Continuing to rotate the housing <NUM> or the driver <NUM>, in direction R2, will apply a torque to the borescope plug <NUM> with respect to the borescope plug port <NUM>, thus rotating and subsequently disengaging the borescope plug <NUM> from the borescope port <NUM>.

Installation of a borescope plug <NUM> into a borescope plug port <NUM> may be accomplished in a manner similar to that discussed above with respect to removal of the borescope plug <NUM>. The borescope plug <NUM> is secured to the housing <NUM> by directing the borescope plug tool <NUM> towards the borescope plug <NUM> and aligning the one or more slots 102E1S of the first housing end 102E1 with the one or more pins 302EP of the borescope plug <NUM> while pulling the driver <NUM> in direction D into a retracted position against the force of the spring <NUM> (see <FIG>). While driver <NUM> is in a retracted position, the housing <NUM> is engaged with the borescope plug <NUM> by rotating the housing <NUM> or the driver <NUM>, in direction R2 for example, to establish twist-lock engagement between the first housing end 102E1 and the exterior surface 302E of the borescope plug <NUM>. Driver <NUM> is then released, causing the spring <NUM> force to return the driver <NUM> to the nominal position, thereby engaging the first driver end 404E1 with the interior surface 302I of the borescope plug <NUM> (see <FIG>). The borescope plug <NUM> is inserted into the borescope plug port <NUM>. Rotating the housing <NUM> or the driver <NUM>, in direction R1 for example (i.e., clockwise), will apply a torque to the borescope plug <NUM> with respect to the borescope plug port, thus rotating and subsequently engaging the borescope plug <NUM> within the borescope port <NUM>. Continuing to rotate the housing <NUM> or the driver <NUM> in direction R1 while pulling the driver <NUM> in direction D into a retracted position against the force of the spring <NUM> will disengage the first housing end 102E1 of the borescope plug tool <NUM> from the borescope plug <NUM>.

<FIG> illustrates an exemplary embodiment of the guiding sleeve <NUM> and the borescope plug tool <NUM> forming a common interface to effect installation or removal of a borescope plug <NUM>. The internal passage <NUM> of the guiding sleeve <NUM> is configured to at least partially encompass the borescope plug tool <NUM> (i.e., the internal passage <NUM> has a large enough diameter to allow the housing <NUM> of the borescope plug tool <NUM> to access and engage the borescope plug <NUM> via the internal passage <NUM>). Operation of the guiding sleeve <NUM> and the borescope plug tool <NUM> to install or remove a borescope plug <NUM> is substantially the same as described above with respect to independent operation of the guiding sleeve <NUM> and the borescope plug tool <NUM>, individually.

As one of ordinary skill in the art will appreciate, installation or removal of a borescope plug <NUM>, as described above with respect to operation of one or more of the guiding sleeve <NUM>, driver <NUM>, and borescope plug tool <NUM>, can be accomplished by a technician using a single hand.

While various embodiments of the present disclosure have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the claims.

Claim 1:
A borescope plug system comprising:
a borescope plug port (<NUM>) including a borescope plug (<NUM>), wherein the borescope plug (<NUM>) is configured to be securely engaged within the borescope plug port (<NUM>); and
a borescope plug tool (<NUM>), the tool comprising:
a housing (<NUM>) comprising a first housing end (102E1) and a second housing end (102E2), the housing (<NUM>) further comprising a longitudinally extending centerline (102CL) extending between the first housing end (102E1) and the second housing end (102E2);
a driver (<NUM>) disposed at least partially within the housing (<NUM>) along the longitudinally extending centerline (102CL) and comprising a first driver end (404E1) and a second driver end (404E2), the first driver end (404E1) and the second driver end (404E2) having an orientation corresponding to the respective first housing end (102E1) and second housing end (102E2); and
a spring (<NUM>), disposed within the housing (<NUM>), and coupling the housing (<NUM>) to the driver (<NUM>);
wherein the driver (<NUM>) is configured to move within the housing (<NUM>), along the longitudinally extending centerline (102CL), to engage the first driver end (404E1) with the borescope plug (<NUM>) of the borescope plug port (<NUM>), and to install or remove the borescope plug (<NUM>) from the borescope plug port (<NUM>) based on a rotation of the driver (<NUM>) about the longitudinally extending centerline (102CL), and
wherein the first housing end (102E1) is configured to engage the borescope plug (<NUM>) with one or more slots (102E1S) of the first housing end (102E1) to secure the borescope plug (<NUM>) to the borescope plug tool (<NUM>), wherein proper engagement between the first housing end (102E1) of the housing (<NUM>) and the borescope plug (<NUM>) is configured to be accomplished by twist-lock engagement between the one or more slots (102E1S) of the first housing end (102E1) and one or more pins (302EP) of the borescope plug (<NUM>).