Patent Description:
Gas turbine engines include compressor sections to compress an airflow, combustor sections that combine the airflow with fuel for combustion and generate exhaust, and turbine sections that convert the exhaust into torque to drive the compressor sections. An isogrid case, having various external and/or internal ribs, may enclose a portion or all of one or more of the compressor section, the combustor section, and the turbine section. It may be desirable to couple various components to the isogrid case to maintain consistent clearance to the case or to provide vibration damping or structural support to the component. For example, it may be desirable to couple one or more cable, harness, pipe or tube to the isogrid case, such harness carrying electrical wiring and the pipe or tube carrying fluids to various components of the gas turbine engine. Conventional methods of coupling these components to isogrid cases include strategically locating thick-walled pads in the case wall where the tubes and other components are to be attached, and coupling the tubes and components to the pads. However, permanent thick-walled mounting pads may fail to offer the ability de-tune unpredicted vibratory issues that may occur during engine operation, and such mounting pads may not be reusable or replaceable. These thick wall pads may also increase manufacturing complexity and provide for inhomogeneity of the part structural requirements, thus further increasing the complexity of the design process.

<CIT> discloses a fibre-reinforced composite casing for a gas turbine engine with a circumferentially extending flange or rib.

<CIT> discloses interlocking support posts forming an interlocking rack system.

<CIT> discloses a clamp mounted to a hollow rib of a panel assembly.

According to a first aspect of the invention, there is provided a clamp for securing a component to an isogrid case of a gas turbine engine as claimed in claim <NUM>.

In any of the foregoing embodiments, each of the two sides defines a boss for receiving a fastener.

In any of the foregoing embodiments, the boss on at least one of the two sides is threaded.

In any of the foregoing embodiments, the attachment feature includes a threaded post formed monolithic with the clamp or coupled to the clamp.

Any of the foregoing embodiments may further include a vibration isolating coating applied to portions of the two sides and the bottom.

In any of the foregoing embodiments, the vibration isolating coating includes at least one of an elastomer or a thermoplastic.

In any of the foregoing embodiments, the clamp is configured to be fastened to the rib of the isogrid case by spreading the two sides apart, placing the shaped slot over the rib, and securing the clamp to the rib using a fastener through the two sides to reduce the likelihood of the two sides separating.

From a further aspect, the invention provides a system for securing components to a gas turbine engine as claimed in claim <NUM>.

The foregoing features and elements are to be combined in various combinations without exclusivity, unless expressly indicated otherwise.

The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present invention, however, is best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures, wherein like numerals denote like elements.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration and their best mode. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the inventions, it should be understood that other embodiments may be realized and that logical, chemical and mechanical changes may be made without departing from the scope of the inventions. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Where used herein, the phrase "at least one of A or B" can include any of "A" only, "B" only, or "A and B.

With reference to <FIG>, a gas turbine engine <NUM> is provided. As used herein, "aft" refers to the direction associated with the tail (e.g., the back end) of an aircraft, or generally, to the direction of exhaust of the gas turbine engine. As used herein, "forward" refers to the direction associated with the nose (e.g., the front end) of an aircraft, or generally, to the direction of flight or motion. As utilized herein, radially inward refers to the negative R direction and radially outward refers to the R direction.

The gas turbine engine <NUM> may be a two-spool turbofan that generally incorporates a fan section <NUM>, a compressor section <NUM>, a combustor section <NUM> and a turbine section <NUM>. In operation, the fan section <NUM> drives air along a bypass flow-path B while the compressor section <NUM> drives air along a core flow-path C for compression and communication into the combustor section <NUM> then expansion through the turbine section <NUM>. Although depicted as a turbofan gas turbine engine <NUM> herein, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures, geared turbofan architectures, and turboshaft or industrial gas turbines with one or more spools.

The gas turbine engine <NUM> generally comprises a low speed spool <NUM> and a high speed spool <NUM> mounted for rotation about an engine central longitudinal axis X-X' relative to an engine static structure <NUM> via several bearing systems <NUM>, <NUM>-<NUM>, and <NUM>-<NUM>. It should be understood that various bearing systems <NUM> at various locations may alternatively or additionally be provided, including for example, the bearing system <NUM>, the bearing system <NUM>-<NUM>, and the bearing system <NUM>-<NUM>.

The low speed spool <NUM> generally includes an inner shaft <NUM> that interconnects a fan <NUM>, a low pressure (or first) compressor section <NUM> and a low pressure (or second) turbine section <NUM>. The inner shaft <NUM> is connected to the fan <NUM> through a geared architecture <NUM> that can drive the fan shaft, and thus the fan <NUM>, at a lower speed than the low speed spool <NUM>. The geared architecture <NUM> includes a gear assembly <NUM> enclosed within a gear diffuser case <NUM>. The gear assembly <NUM> couples the inner shaft <NUM> to a rotating fan structure.

The high speed spool <NUM> includes an outer shaft <NUM> that interconnects a high pressure (or second) compressor section <NUM> and the high pressure (or first) turbine section <NUM>. A combustor <NUM> is located between the high pressure compressor <NUM> and the high pressure turbine <NUM>. A mid-turbine frame <NUM> of the engine static structure <NUM> is located generally between the high pressure turbine <NUM> and the low pressure turbine <NUM>. The mid-turbine frame <NUM> supports one or more bearing systems <NUM> in the turbine section <NUM>. The inner shaft <NUM> and the outer shaft <NUM> are concentric and rotate via the bearing systems <NUM> about the engine central longitudinal axis X-X', which is collinear with their longitudinal axes. As used herein, a "high pressure" compressor or turbine experiences a higher pressure than a corresponding "low pressure" compressor or turbine.

The core airflow C is compressed by the low pressure compressor section <NUM> then the high pressure compressor <NUM>, mixed and burned with fuel in the combustor <NUM>, then expanded over the high pressure turbine <NUM> and the low pressure turbine <NUM>. The mid-turbine frame <NUM> includes airfoils <NUM> which are in the core airflow path.

The gas turbine engine <NUM> is a high-bypass ratio geared aircraft engine. The bypass ratio of the gas turbine engine <NUM> may be greater than about six (<NUM>). The bypass ratio of the gas turbine engine <NUM> may also be greater than ten (<NUM>:<NUM>). The geared architecture <NUM> may be an epicyclic gear train, such as a star gear system (sun gear in meshing engagement with a plurality of star gears supported by a carrier and in meshing engagement with a ring gear) or other gear system. The geared architecture <NUM> may have a gear reduction ratio of greater than about <NUM> and the low pressure turbine <NUM> may have a pressure ratio that is greater than about five (<NUM>). The diameter of the fan <NUM> may be significantly larger than that of the low pressure compressor section <NUM>, and the low pressure turbine <NUM> may have a pressure ratio that is greater than about five (<NUM>:<NUM>). The pressure ratio of the low pressure turbine <NUM> is measured prior to an inlet of the low pressure turbine <NUM> as related to the pressure at the outlet of the low pressure turbine <NUM>. It should be understood, however, that the above parameters are exemplary of various embodiments of a suitable geared architecture engine and that the present invention contemplates other turbine engines including direct drive turbofans.

The next generation turbofan engines are designed for higher efficiency and use higher pressure ratios and higher temperatures in the high pressure compressor <NUM> than are conventionally experienced. These higher operating temperatures and pressure ratios create operating environments that cause thermal loads that are higher than the thermal loads conventionally experienced, which may shorten the operational life of current components.

The gas turbine engine <NUM> may further include a case <NUM>. In various embodiments, the case <NUM> may be an isogrid case, meaning that the case may include one or more ribs on at least one of an outer surface or an inner surface. Frequently, the ribs are wider on an end furthest from a case in order to provide increased stiffness contributed by the rib. The rib may be used to fasten, couple, or otherwise attached a component (such as a cable, harness, pipe, tube, or the like) to the case <NUM>.

In particular and referring to <FIG>, the isogrid case <NUM> may include a plurality of ribs <NUM> including a first rib <NUM>. The plurality of ribs <NUM> may form any shape or pattern, and may extend from a surface <NUM> of the isogrid case <NUM>. In various embodiments, the surface <NUM> is generally an outer surface (i.e., facing away from the axis X-X' of <FIG>) for ease of installation and removal of external components, but may be an inner surface (i.e., facing towards the axis X-X' of <FIG>).

Turning now to <FIG>, a cross-sectional view of the rib <NUM> is shown. As shown, the rib <NUM> may extend away from the surface <NUM> of the isogrid case <NUM>. The rib <NUM> including a vertical portion <NUM> extending substantially at a right angle <NUM> from the surface <NUM>, and a horizontal portion <NUM> extending in a direction substantially parallel to the surface <NUM>. In that regard, a substantially right angle <NUM> being formed between the vertical portion <NUM> and the horizontal portion <NUM>. Where used in this context, "substantially" may refer to the angle plus or minus <NUM> degrees, plus or minus <NUM> degrees, plus or minus <NUM> degrees, or the like.

Referring now to <FIG>, an exemplary use of the isogrid case <NUM> is shown. In particular, a clamp <NUM> may be fastened or otherwise attached to the rib <NUM>. An adapter <NUM> may be coupled to the clamp <NUM> and may likewise be coupled to a tube <NUM>. In that regard, the tube <NUM> may be coupled to the isogrid case <NUM> via the adapter <NUM> and the clamp <NUM>. Multiple clamps <NUM> may be coupled to the various ribs of the isogrid case <NUM> in order to fasten various components to the isogrid case <NUM>. Additionally, the clamp <NUM> and the adapter <NUM> may be reusable such that they may be moved to various locations on the isogrid case <NUM> and used to couple multiple components to the isogrid case <NUM>.

The tube <NUM> may be coupled to the clamp <NUM> via a thin-walled split metal clamp <NUM> surrounding a split rubber bushing <NUM>. The thin-walled split metal clamp <NUM> may be coupled to the clamp <NUM> via a threaded post <NUM> (as shown in more detail in <FIG>).

Referring now to <FIG>, additional details of the clamp <NUM> are shown. All portions of the clamp <NUM> are formed integrally, or monolithically, together and thus are or include a single piece of material. The clamp <NUM> includes a top <NUM>, a bottom <NUM>, and two sides <NUM> including a first side <NUM> and a second side <NUM>. In various embodiments, some portions of the clamp (such as an attachment feature <NUM>) may be formed separate from the clamp <NUM> and may be coupled to the clamp <NUM> after forming the clamp <NUM> and the attachment feature <NUM> separately. In various embodiments, multiple portions of the clamp (up to and including all portions) may be formed separately and may be coupled together using any technique (e.g., welding, brazing, etc.) to form the clamp <NUM>.

The clamp <NUM> may include the attachment feature <NUM> extending away from the top <NUM>. In various embodiments, the attachment feature <NUM> may include a threaded post <NUM>. Any component or adapter (such as the adapter <NUM> of <FIG>) may be coupled to the clamp <NUM> via the attachment feature <NUM>. For example, the adapter <NUM> of <FIG> may include an internal clearance hole and may be coupled with two threaded nuts for adjustably attaching rigidly the threaded post <NUM>. In various embodiments, the attachment feature <NUM> may include any other type of attachment feature such as a snap fit, a threaded aperture, or the like. In various embodiments, a filet <NUM> may be formed at the transition of the top <NUM> and the threaded post <NUM>.

The two sides <NUM> may be thicker towards the bottom <NUM> of the clamp <NUM> than towards the top <NUM>. In that regard, the two sides <NUM> may have a first thickness <NUM> and a second thickness <NUM> that is closer to the bottom <NUM> than the first thickness <NUM>. Such a design results in a central opening <NUM> defined between the two sides <NUM>. This design desirably reduces a total weight of the clamp <NUM>.

The portion of the two sides <NUM> below the central opening <NUM> defines a shaped slot <NUM>. The shaped slot <NUM> may have a shape that at least partially matches the cross-sectional shape of the rib <NUM> of <FIG>. That is, the shaped slot <NUM> having a vertical portion <NUM> having a similar shape and dimension as the vertical portion <NUM> of the rib <NUM> of <FIG>, and having a horizontal portion <NUM> having a similar shape and dimension as the horizontal portion <NUM> of the rib <NUM> of <FIG>.

The shaped slot <NUM> may extend from the bottom <NUM> to the central opening <NUM>. In that regard, the two sides <NUM> may be forced apart, the shaped slot <NUM> may be placed over the rib <NUM> of <FIG>, and the two sides <NUM> may be released such that the rib <NUM> is enclosed within the shaped slot <NUM>. Such actions, along with the shape of the shaped slot <NUM> and the shape of the rib <NUM> of <FIG>, results in the clamp <NUM> being at least partially coupled to the rib <NUM>.

The two sides <NUM> may each include or define a boss used for receiving a fastener. In particular, the first side <NUM> may define a first boss <NUM>, and the second side <NUM> may define a second boss <NUM>. In various embodiments, one or both of the bosses <NUM>, <NUM> may include or define a threading <NUM>. In that regard, after the clamp <NUM> has been positioned over the rib <NUM> of <FIG>, a fastener (such as a bolt, screw, or the like) may be inserted through the bosses <NUM>, <NUM> and fastened in order to secure the clamp <NUM> to the rib <NUM>.

Lightening holes <NUM>, <NUM> are formed through the two sides <NUM> at the thicker portions of the two sides <NUM> (i.e., the portions between the central opening <NUM> and the bottom <NUM>). The lightening holes <NUM>, <NUM> may extend through a portion or all of a length <NUM> of the clamp <NUM>. In various embodiments, any quantity and shape of lightening holes <NUM>, <NUM> may be formed or included in the clamp <NUM>. The lightening holes <NUM>, <NUM> may desirably reduce a total weight of the clamp <NUM>.

In various embodiments, a portion or all of the clamp <NUM> may be coated with a vibration isolating coating <NUM>. For example, the bottom <NUM> and the surfaces defining the shaped slot <NUM> may be coated with the vibration isolating coating <NUM>. In various embodiments, the surfaces defining the holes of the bosses <NUM>, <NUM> may likewise be coated with the vibration isolating coating <NUM>. In various embodiments, each surface of the clamp <NUM> which contacts another component (e.g., surfaces of the clamp <NUM> which contact the rib <NUM> and the surface <NUM> of the isogrid case <NUM> of <FIG>, along with the fastener received by the bosses <NUM>, <NUM>) may be coated with the vibration isolating coating <NUM>.

In various embodiments, the vibration isolating coating <NUM> may include any one or more of an elastomer or a thermoplastic. It is desirable for the thermoplastic or elastomer to be non-wearing to the bosses <NUM>, <NUM> or the isogrid case <NUM> but still durable in the operating temperature and environment of the clamp <NUM>. The thermoplastic may include but is not limited to polyetheretherketone (PEEK), polyetherketone (PEK), polyetherimide (PEI), thermoplastic polyimide, polyamideimide (PAI), or a polytetrafluoroethene (PTFE). The vibration isolating coating <NUM> may be applied in any known manner such as dipping the clamp <NUM> into a fluid coating, brushing a fluid coating onto the clamp <NUM>, spraying a fluid coating onto the clamp <NUM>, or the like.

In various embodiments, the vibration isolating coating <NUM> may include a preformed material (such as a cushion, a foam, or another compressible material) which may be retained in place relative to the respective portion of the clamp <NUM>. In various embodiments, a cushion version of the vibration isolating coating <NUM> may be coupled to the clamp <NUM> using any known method such as a compression fit (e.g., the vibration isolating coating <NUM> may be compressed between the clamp <NUM> and the rib), use of an adhesive, use of a fastener, or the like.

The vibration isolating coating <NUM> may reduce or eliminate the passage of vibrational energy from a component or object on one side of the vibration isolating coating <NUM> to a component or object on another side of the vibration isolating coating <NUM>. In that regard, the vibration isolation coating <NUM> may provide vibration isolation capabilities.

The clamp <NUM> may have a height <NUM>, a length <NUM>, a top width <NUM> at the top <NUM>, and a bottom width <NUM> at the bottom <NUM>. In various embodiments, the height <NUM> may be between <NUM> inch and <NUM> inches (<NUM> centimeters (cm) and <NUM>), between <NUM> inch and <NUM> inches (<NUM> and <NUM>), or between <NUM> inches and <NUM> inches (<NUM> and <NUM>).

In various embodiments, the length <NUM> may be between <NUM> inches and <NUM> inches (<NUM> and <NUM>), between <NUM> inches and <NUM> inch (<NUM> and <NUM>), or about <NUM> inches (<NUM>). Where used in this context, about refers to the referenced value plus or minus <NUM> percent of the referenced value.

In various embodiments, the top width <NUM> may be between <NUM> inches and <NUM> inch (<NUM> and <NUM>), between <NUM> inches and <NUM> inches (<NUM> and <NUM>), or about <NUM> inches (<NUM>). In various embodiments, the bottom width <NUM> may be between <NUM> inches and <NUM> inches (<NUM> and <NUM>), between <NUM> inches and <NUM> inches (<NUM> and <NUM>), or about <NUM> inches (<NUM>).

In various embodiments, the clamp <NUM> may be formed from a metal such as aluminum, titanium, steel, a metal alloy, or the like. The clamp <NUM> may be formed using any known method such as casting, forging, additive manufacturing, or the like.

The clamp <NUM> may provide various benefits over conventional methods of coupling components to isogrid cases. In particular, the clamp <NUM> may be reused over and over without damaging any portion of the isogrid case. Additionally, the clamp <NUM> provides improved damping over conventional methods of coupling components to isogrid cases, reducing or eliminating vibratory issues with components coupled to the isogrid case. The clamp <NUM> further provides improved structural integrity over conventional methods of coupling components to isogrid cases.

However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the inventions. The scope of the invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more.

Claim 1:
A clamp (<NUM>) for securing a component to an isogrid case (<NUM>) of a gas turbine engine (<NUM>), the clamp comprising:
a top (<NUM>) having an attachment feature (<NUM>) for coupling the clamp to the component;
a bottom (<NUM>); and
two sides (<NUM>) extending from the top towards the bottom, each of the two sides being thicker at the bottom than at the top, and the two sides defining a shaped slot (<NUM>) closer to the bottom than the top for receiving a rib (<NUM>) of the isogrid case,
the rib having a vertical portion (<NUM>) extending substantially at a right angle from a surface (<NUM>) of the isogrid case,
the clamp comprising a central opening (<NUM>) defined between the two sides (<NUM>),
characterised by the rib having a horizontal portion (<NUM>) extending in a direction substantially parallel to the surface, and
a substantially right angle being formed between the vertical portion and the horizontal portion of the rib, and
the shaped slot having a vertical portion (<NUM>) having a similar shape and dimension of the vertical portion of the rib,
the shaped slot (<NUM>) having a horizontal portion (<NUM>) having a similar shape and dimension as the horizontal portion of the rib,
each of the two sides (<NUM>) defining a lightening hole (<NUM>; <NUM>) closer to the bottom (<NUM>) than the top (<NUM>) and configured to reduce a total weight of the clamp,
all portions of the clamp being formed integrally together, and
a portion of the two sides below the central opening (<NUM>) defining the shaped slot (<NUM>).