Adjustable fittings for attaching support members to fluid conduits, including aircraft fuel conduits, and associated systems and methods

Adjustable fittings for attaching support members to fluid conduits, including aircraft fuel conduits, are disclosed herein. An aircraft system in accordance with one embodiment of the invention includes a fluid conduit carried by an aircraft and a housing fixedly attached to the fluid conduit. The housing can include a first attachment feature having one of a projection extending outwardly from the housing or an aperture extending at least partially through the housing. The system further includes a support member having an attachment portion positioned proximate to the attachment feature. The attachment portion includes a support member aperture positioned over at least a portion of the first attachment feature. An adjustable fitting couples the support member to the housing. The adjustable fitting can include a first side, a second side opposite the first side, and an engagement portion at the second side positioned within at least a portion of the support member aperture. The fitting can also include a second attachment feature mated with the first attachment feature. The second attachment feature includes the other one of the projection or the aperture. The second attachment feature has a center point eccentrically offset from a center point of the fitting.

TECHNICAL FIELD

The present invention is directed generally toward adjustable fittings for attaching support members to fluid conduits, including aircraft fuel conduits, and associated systems and methods.

BACKGROUND

Modern aircraft include complex fuel systems that route aviation fuel from fuel tanks to aircraft systems that use the fuel. These aircraft systems can include the primary engines and/or auxiliary power units (APUs). In the case of an aerial refueling tanker and/or receiver aircraft, these systems can also include the fluid conduits (e.g., fuel lines), manifolds, and associated valving necessary for delivering fuel to a receiver aircraft and/or receiving fuel in-flight from a tanker aircraft. In some cases, the fuel lines may pass through “ignition zones,” which are typically pressurized compartments in the aircraft (e.g., baggage compartments) that may also house electrical devices.

One concern with this arrangement is that the fuel passing through the fluid conduits imparts substantial loads (e.g., surge loads and pressure loads) on the fluid conduits. Accordingly, in many cases support members are attached to various portions of the fluid conduits to distribute and/or transfer the imposed loads to appropriate reaction locations of the aircraft. The support members are generally attached to corresponding fluid conduits with one or more fittings. Many conventional fittings, however, cannot withstand the imposed loads.

Another concern with the above-described arrangement is that the support members generally include suitable tolerances to compensate for the manufacturing tolerances between the various components. Most conventional fittings, however, are not configured to compensate for the various manufacturing tolerances between the different components and, accordingly, a number of different support members and/or fittings have to be manufactured for particular installations. Accordingly, there is a need for fittings configured to withstand the imposed loads while keeping the attached support members in place with respect to the fluid conduits.

SUMMARY

The invention is directed generally to adjustable fittings for attaching support members to fluid conduits, including aircraft fuel conduits, and associated methods. An aircraft system in accordance with one embodiment of the invention includes a fluid conduit carried by an aircraft and a housing fixedly attached to the fluid conduit. The housing can include a first attachment feature having one of a projection extending outwardly from the housing or an aperture extending at least partially through the housing. The system further includes a support member having an attachment portion positioned proximate to the attachment feature. The attachment portion includes a support member aperture positioned over at least a portion of the first attachment feature. An adjustable fitting couples the support member to the housing. The adjustable fitting can include a first side, a second side opposite the first side, and an engagement portion at the second side positioned within at least a portion of the support member aperture. The fitting can also include a second attachment feature mated with the first attachment feature. The second attachment feature includes the other one of the projection or the aperture. The second attachment feature has a center point eccentrically offset from a center point of the fitting. After initial installation, the adjustable fitting is rotatable with respect to the first attachment feature to secure the fitting in place against the support member and the housing.

Another aspect of the invention is directed to an assembly including a first member coupled to a second member with an adjustable fitting. The first member can have a first attachment feature including one of a projection extending outwardly from the first member or an aperture extending at least partially through the first member. The second member, which is positioned proximate to the first member, can include a second member aperture positioned over at least a portion of the first attachment feature. The adjustable fitting coupling the first member to the second member can include a first side facing away from the first member and a second side facing toward the first member. The second side can include an engagement portion positioned within at least a portion of the second member aperture. The fitting can further include a second attachment mated with the first attachment feature. The second attachment feature has the other one of the projection or the aperture. The second attachment feature has a center point eccentrically offset from a center point of the adjustable fitting. After initially installing the fitting, the fitting can be rotated in a generally clockwise and/or counterclockwise direction to releasably secure the fitting against at least a portion of the first attachment feature.

Still another aspect of the invention is directed to a method for installing a support member with a fluid conduit. The method can include positioning a support member proximate to a fluid conduit. The support member includes a support member aperture positioned over at least a portion of a first attachment feature carried by the fluid conduit. The method can also include inserting at least a portion of an adjustable fitting having a second attachment feature through the support member aperture and mating the first and second attachment features. The second attachment feature is eccentrically offset from a center point of the adjustable fitting. The method can further include rotating the fitting with respect to the first attachment feature until the second attachment feature fixedly engages at least a portion of the first attachment feature to secure the support member in place with respect to the fluid conduit.

DETAILED DESCRIPTION

The present disclosure describes adjustable fittings for securing support members to fluid conduits, such as aircraft fuel lines and other systems, and also discloses associated methods. Certain specific details are set forth in the following description and inFIG. 1-4Bto provide a thorough understanding of various embodiments of the invention. Well-known structures, systems, and methods often associated with such systems have not been shown or described in detail to avoid unnecessarily obscuring the description of the various embodiments of the invention. In addition, those of ordinary skill in the relevant art will understand that additional embodiments of the invention may be practiced without several of the details described below.

FIG. 1illustrates an aircraft100(e.g., a refueling aircraft) in the process of refueling a receiver aircraft120with an aerial refueling device114. The aircraft100can include a fuselage101, wings102, and one or more engines103(two are shown inFIG. 1as being carried by the wings102). In other embodiments, the aircraft can have other configurations and, in at least some embodiments, need not include a refueling capability. In a particular aspect of the embodiment shown inFIG. 1, the aircraft100includes a fuel system110having wing-mounted fuel tanks111and fluid conduits130(e.g., fuel lines) that provide fuel to other aircraft systems. These systems can include the engines103, an APU105, and an aerial refueling system113. The fluid conduits130can also include one or more support members140(shown schematically) coupled to the fluid conduits130with one or more adjustable fittings (not shown). The support members140are positioned to distribute and/or transfer the imposed loads (e.g., surge loads and pressure loads from fluid movement) on the fluid conduits130to appropriate reaction locations of the aircraft100. Aspects of the invention are directed to the adjustable fittings that couple the support members140to the fluid conduits130, as described in greater detail below with reference toFIG. 2A-4B.

FIG. 2A-2Dare illustrations of various stages of a method for using adjustable fittings to couple support members to a fluid conduit in accordance with an embodiment of the invention.FIG. 2A, for example, is an isometric illustration of a preliminary stage of the method illustrating two support members140positioned for attachment to a portion of the fluid conduit130with adjustable fittings160. The fluid conduit130in the illustrated embodiment can include a first or inner conduit131surrounded by a second or outer conduit132. The inner conduit131can be configured to carry fuel or other types of liquids. The outer conduit132can provide a protective shroud around the inner conduit131in case of a liquid and/or vapor leak in the inner conduit131. Accordingly, the inner conduit131and outer conduit132are normally isolated from fluid communication with each other. Suitable shrouded fuel conduits are disclosed in U.S. Pat. No. 6,848,720, which is incorporated herein by reference. In other embodiments, however, the fluid conduit130may have other configurations.

The fluid conduit130can also include one or more housings134attached to the fluid conduit130. In the illustrated embodiment, for example, the housings134are load-carrying supports fixedly attached to the fluid conduit130at desired locations. In other embodiments, however, the housings134can have other configurations and/or functions. The housings134also include one or more first attachment features135positioned for engagement with the adjustable fittings160for coupling the support members140to the fluid conduit130. In the embodiment shown inFIG. 2A, the first attachment features135are generally cylindrical projections extending outwardly away from the housings134. In other embodiments, however, the first attachment features135may have other configurations. The first attachment features135can also include threaded apertures136for receiving a fastener (e.g., a bolt) to secure the adjustable fittings160in place after engagement, as described in detail below with respect toFIG. 2D.

The support members140each include a base portion142, a first attachment portion144having a first aperture146, and a second attachment portion148having a second aperture150. In one aspect of this embodiment, the first and second apertures146and150have approximately the same diameter. In other embodiments, however, the first and second apertures146and150can be different sizes. The first and second apertures146and150are positioned proximate to corresponding first attachment features135on the housings134. In the illustrated embodiment, for example, the first and second apertures146and150are positioned at least approximately around the periphery of the corresponding first attachment features135. In other embodiments, the support members140may be positioned differently with respect to the first attachment features135.

FIG. 2Bis a plan view of one of the adjustable fittings160. Referring toFIGS. 2A and 2Btogether, each adjustable fitting160includes a first side161and a second side162opposite the first side161. The first side161of each fitting160can include a first annular portion164, a second annular portion166having a diameter less then the diameter of the first annular portion164, and a fitting aperture168extending completely through the fitting160. The outer diameter of the first annular portion164is dimensioned to correspond at least in part to the diameter of the first and second attachment portions144and148of the support members140. The second side162of each fitting160can include an engagement portion170positioned for engagement with the support members140. More specifically, the engagement portions170are sized to be received within at least a portion of the corresponding apertures146and150of the support members140.

The fitting apertures168are second attachment features configured to mate with or otherwise engage corresponding first attachment features135. In the illustrated embodiment, for example, the individual fitting apertures168(i.e., second attachment features) are sized to receive at least a portion of each first attachment feature135when the fittings160are engaged with the support members140. As best seen inFIG. 2B, the fitting aperture168of each adjustable fitting160has a center point B eccentrically offset from a center point A of the fitting160itself (as defined by the outer diameter of the first annular portion164). The dimension of the offset in each fitting160can vary based on the particular operational requirements for the fitting. For example, several fittings160may have greater offsets to accommodate greater tolerances between the respective parts. Alternatively, if the parts have less tolerance, the offset dimension can be smaller.

FIG. 2Cis an isometric view of the area2C ofFIG. 2Ashowing one of the adjustable fittings160engaged with the support member140and the housing134to releasably couple the support member to the fluid conduit130. Although only one adjustable fitting160is shown inFIG. 2C, it will be appreciated that each of the adjustable fittings160shown inFIG. 2Acan be engaged with the corresponding support member140and housing134in a manner generally similar to that illustrated inFIG. 2C. The engagement portion170(shown in broken lines) of the adjustable fitting160is received within the first aperture146(shown in broken lines) of the first attachment portion144of the support member140and the second side162of the fitting160is in contact with at least a portion of the first attachment portion144of the support member140. The fitting aperture168receives at least a portion of the first attachment feature135. In one aspect of this embodiment, the center point B (FIG. 2B) of the fitting160is eccentrically offset from a center point of the generally arcuate or circular end portion of the first attachment feature135.

After the first attachment feature135is received within the fitting aperture168, the adjustable fitting160can be rotated in a clockwise and/or counterclockwise direction (as shown by the arrow R) to lock or otherwise secure the fitting160in place with respect to the first attachment feature135. More specifically, during rotation of the adjustable fitting160, the fitting aperture168maintains a generally eccentric orbit about the center point of the end portion of the first attachment feature135until a portion of the fitting aperture168engages at least a portion of the first attachment feature135, thus preventing further rotation of the fitting aperture168about the center point of the end portion of the first attachment feature135and, accordingly, releasably securing the support member140to the housing134. One advantage this feature is that it allows the engagement portion170and the fitting aperture168of the adjustable fitting160to fit within the first aperture146and over the first attachment feature135, respectively, while accounting for manufacturing tolerances in both the relative location of the first attachment feature135and expansion/contraction of the various components during fabrication. In several embodiments in which the tolerances between the respective parts are extremely small, the fitting aperture168and the center point of the end portion of the first attachment feature135can be approximately concentrically aligned after engagement with each other. In other embodiments, however, the fitting aperture168and the center point of the end of the first attachment feature135are not concentrically aligned after engagement.

FIG. 2Dis an isometric illustration of an end portion of the fluid conduit130with a cut-away portion showing further details of the adjustable fittings160after the fittings160are installed with the support members140and corresponding first attachment features135. In one aspect of this embodiment, the fittings160can be fixedly attached to the support members140with retaining hardware180(e.g., bolts) after the adjustable fittings160are rotated and locked in place with respect to the first attachment features135as described above with reference toFIG. 2C. The individual fittings160can be secured to the housing134using a fastener182(e.g., a bolt) and, optionally, a retaining member184(e.g., a washer). The retaining members184can be positioned within at least a portion of the second annular portion166of the individual fittings160and the fasteners182can be engaged with the corresponding threaded apertures136of the first attachment features135to hold the retaining member184in place. In this way, the support members140are secured in place with respect to the fluid conduit130and the support members140can distribute and/or transfer the various loads imposed on the fluid conduit130. In other embodiments, the adjustable fittings160can be fixedly secured to the support members140and/or the first attachment features135using other arrangements.

One feature of at least some of the embodiments of the adjustable fittings160described above is that the eccentrically offset arrangement of the fitting apertures168(the second attachment features) with respect to the first attachment features135can account for manufacturing tolerances between the various components. An advantage of this feature is that it allows for interchangeability of parts (e.g., support members) and allows a single type of part to be used universally throughout a system. For example, support members140having the same configuration could be used at various portions of the fluid conduits130of the aircraft100(FIG. 1) without having to custom fit and/or manufacture unique support members at each location. Accordingly, this feature can significantly reduce the time and expense of manufacturing and/or retrofitting.

Another feature of at least some of the embodiments of the adjustable fittings160described above is that they can be installed and removed with common hand tools. For example, the connections between the fastener182and the first attachment features135can be threaded connections that can be secured and released with wrenches or other suitable hand tools. An advantage of this feature is that it can reduce the time and cost associated with installation and removal of the support members140with respect to the fluid conduits130.

FIG. 3is an isometric illustration of a stage of a method for using adjustable fittings to couple support members to fluid conduits in accordance with another embodiment of the invention. More specifically,FIG. 3is an isometric view illustrating an adjustable fitting260positioned for attachment with the support member140and a housing234carried by the fluid conduit130. The adjustable fitting260and housing234can be generally similar to the fitting160and housing134described above with reference toFIGS. 2A and 2B. The fitting260and housing234illustrated inFIG. 3differ from the fitting160and housing134described above, however, in that the engagement portions of the respective parts are reversed. For example, the adjustable fitting260includes a first attachment feature265projecting outwardly from the fitting260and the housing234includes a second attachment feature235(e.g., an aperture) positioned to receive at least a portion of the corresponding first attachment feature265. After the second attachment feature235receives the first attachment feature265, the fitting260can be rotated in a clockwise and/or counterclockwise direction to lock or otherwise secure the fitting260in place with respect to the housing234, as described in greater detail above with reference toFIGS. 2C and 2D. In other embodiments, the first and/or second attachment features can have other configurations.

From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the invention. For example, the adjustable fittings may have other configurations. Referring toFIG. 4A, an adjustable fitting360configured in accordance with another embodiment of the invention may not include the second annular portion on a first side361of the fitting360and may instead only include a first annular portion364. In still another embodiment shown inFIG. 4B, an adjustable fitting460may have a fitting aperture468that does not extend completely through the fitting460. For example, the fitting aperture468extends from a second side462of the fitting460to an intermediate depth between a first side461and the second side462of the fitting460. Although the fitting aperture468does not extend completely through the fitting460, the fitting aperture468is still sized to receive the necessary portion of an attachment feature to secure the fitting in place with respect to the support member and fluid conduit. Aspects of the invention described in the context of particular embodiments may be combined or eliminated in other embodiments. For example, the fluid conduits can be used to transfer liquids other than fuel. Further, aspects of the invention described in the context of the specific systems of the aircraft can be implemented in other systems and/or can be implemented in vehicles or devices other than aircraft. Moreover, the adjustable fittings may be used to couple any type of first member to a corresponding second member, and are not limited to fluid conduits and/or support members. Further, while advantages associated with certain embodiments of the invention have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited, except as by the appended claims.