Patent Description:
Aircraft include various structural members that form portions of a fuselage. For example, a longeron is a fore and aft structural member that is used to form a portion of a fuselage. The longeron is a load-bearing portion of a framework, such as a fuselage of an aircraft.

Certain known under-wing longerons may experience physical irregularities, such as those that can be caused by deflection-induced bending moments caused by complex load paths in an area of the aircraft where a mismatch between wing and fuselage motion is acute and appreciable. Typical under-wing longeron configurations are built up assemblies including several fasteners that fix all degrees of translation and rotation between the wing and fuselage. For example, the longeron is typically fixed along its length at points on the wing and/or fuselage through numerous fasteners.

Under load, the wing may move in a substantially different fashion than the fuselage, imposing appreciable induced moments about the vertical and horizontal axes on the under-wing longeron. These moments are resolved through rigid attachments to the wing and fuselage supporting structure. The resulting loads on the under-wing longeron and attachments are complex and difficult to characterize. Further, due to the imposed deflection nature of such loading, appropriate sizing is complicated by the fact that stronger and stiffer structure attracts more load in an imposed deflection loading environment. The challenge in relation to properly characterizing the load paths and subsequently sizing for the loading environment may cause irregularities in relation to the under-wing longeron.

Document <CIT>, in accordance with its abstract, states an airframe for a tiltrotor aircraft that includes a wing airframe including a rib, a fuselage airframe including a fore-aft overhead beam and a cradle support assembly. The cradle support assembly includes a forward wing support coupled to the fore-aft overhead beam and the wing airframe and an aft wing support coupled to the fore-aft overhead beam and the wing airframe. The rib, the fore-aft overhead beam, the forward wing support and the aft wing support are substantially aligned to form a wing-fuselage integrated airframe beam assembly to support the wing airframe.

Document <CIT>, in accordance with its abstract, states an aircraft featuring a fuselage, a wing member, and two fuselage beams. The fuselage features a first plurality of structural supports, a second plurality of structural supports, a first opening disposed between the first plurality of structural supports, and a second opening disposed between the second plurality of structural supports. The wing member is disposed above the first opening and above the second opening. The wing features a plurality of ribs including a first rib and a second rib. The first fuselage beam couples the first rib of the wing member to the fuselage and has an elongated body portion extending across the first plurality of structural supports. The second fuselage beam couples the second rib of the wing member to the fuselage and features an elongated body portion extending across the second plurality of structural supports.

Document <CIT>, in accordance with its abstract, states a wing-fuselage connection of an aircraft, in which a wing that is arranged in the upper region of the fuselage is connected to the fuselage by means of a number of couplings, wherein the couplings are provided for taking up forces in various directions and are designed for a maximum load carrying capacity, in particular for a nominal flight- and landing load or a nominal crash load. According to the invention, the load carrying capacity of the individual wing couplings and their direction of force take-up are matched to each other such that in the case of a defect in one of the couplings the maximum load carrying capacity of the remaining couplings is adequate for safe normal flight operation.

Document <CIT>, in accordance with its abstract, states methods and systems for attaching aircraft wings to fuselages are disclosed herein. An aircraft includes a fuselage and a wing. The wing includes a right wing portion extending outwardly from a right side portion of the fuselage and a left wing portion extending outwardly from a left side portion of the fuselage. The right wing portion is fixedly attached to the left wing portion by a wing center section extending through at least a portion of the fuselage. The aircraft further includes a first pivotable link structurally attaching the wing center section to the right side portion of the fuselage, and a second pivotable link structurally attaching the wing center section to the left side portion of the fuselage.

Moreover, the build process requires several attachment fasteners that are to be drilled and installed in a final assembly, increasing factory flow times. Accordingly, the process of securing an under-wing longeron to a wing and a fuselage is typically time and labor intensive.

A need exists for a longeron that is configured to readily adapt to forces exerted on and in relation to a fuselage and a wing. Further, a need exists for a longeron that can be quickly and efficiently secured to a fuselage and a wing.

With those needs in mind, certain examples of the subject disclosure provide a system for securing a portion of a fuselage of an aircraft to a portion of a wing of the aircraft according to claim <NUM>. The system includes a longeron having a first end and a second end, a first moveable coupling interface that moveably secures the first end to the portion of the fuselage, and a second moveable coupling interface that moveably secures the second end to the portion of the wing.

The portion of the wing is an underside of the wing that is aft in relation to a front edge of the wing. The portion of the fuselage is in front of and below the wing.

The fuselage includes a first support fitting that secures to the first moveable coupling interface. The wing includes a second support fitting that secures to the second moveable coupling interface.

In at least one example, one or both of the first moveable coupling interface or the second moveable coupling interface includes a spherical bearing moveably retained within a reciprocal bushing. As a further example, one or both of the spherical bearing or the reciprocal bushing are secured to the portion of the fuselage or the portion of the wing.

In at least one example, the first end and the second end are not rigidly fixed in position with respect to the fuselage and the wing. Further, a length of the longeron between the first end and the second end is free. Additionally, the length of the longeron is devoid of fasteners.

Certain examples of the subject disclosure provide a method for securing a portion of a fuselage of an aircraft to a portion of a wing of the aircraft. The method includes moveably securing, by a first moveable coupling interface, a first end of a longeron to the portion of the fuselage; and moveably securing, by a second moveable coupling interface, a second end of the longeron to the portion of the wing.

Certain examples of the subject disclosure provide an aircraft including a fuselage, a wing coupled to the fuselage, and a system for securing a portion of the fuselage of to a portion of the wing, as described herein.

The foregoing summary, as well as the following detailed description of certain embodiments will be better understood when read in conjunction with the appended drawings. Further, references to "one embodiment" are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments "comprising" or "having" an element or a plurality of elements having a particular condition can include additional elements not having that condition.

Certain examples of the subject disclosure provide a system and a method for securing a portion of a wing of an aircraft to a portion of a fuselage. In at least one example, the system and method include a longeron linked to an aft end connecting to a lug fitting on an underside of the wing center section lower panel and a forward end connecting to a lug fitting on a fuselage frame forward of a wing front spar. In at least one embodiment, the system and method include a pin-ended structure at such locations. The use of spherical bearings at the two points of attachment result in a two-force member under-wing longeron with subsequent load paths that are significantly simplified compared to the traditional design. The system and method also reduce the amount of deflection induced loading on the longeron and supporting structures.

Structure can be sized for applied loads with little regard for induced loads. The amount of time required to install the longeron in final assembly is also greatly improved by the removal of drill and fill operations.

By using a pin-ended design, the longeron is relieved of induced moments and can better fulfill its structural purpose, which is to provide a fore/aft load path between the fuselage and wing. Additionally, this configuration serves as an enabler to reduce production system flow time in wing to body join processes. Traditional architectures require drilling assembly operations to install the under-wing longeron. This configuration simplifies and expedites the wing to body join procedure by eliminating or otherwise reducing drilling operations in this position and replacing them with simple pin installation, pin joint clamp up, and pin retention operations which are much easier and faster to complete.

<FIG> illustrates a perspective front view of an aircraft <NUM>, according to an embodiment of the present disclosure. The aircraft <NUM> includes a propulsion system <NUM> that includes engines <NUM>, for example. Optionally, the propulsion system <NUM> may include more engines <NUM> than shown. The engines <NUM> are carried by wings <NUM> of the aircraft <NUM>. In other embodiments, the engines <NUM> may be carried by a fuselage <NUM> and/or an empennage <NUM>. The empennage <NUM> may also support horizontal stabilizers <NUM> and a vertical stabilizer <NUM>. The fuselage <NUM> of the aircraft <NUM> defines an internal cabin <NUM>, which includes a flight deck or cockpit.

The aircraft <NUM> can be sized, shaped, and configured other than shown. As described herein, the aircraft <NUM> includes a system for securing a portion of a wing <NUM> to the fuselage <NUM>.

<FIG> illustrates a perspective lateral view of the aircraft <NUM>, according to an example of the subject disclosure. The aircraft <NUM> includes a system <NUM> for securing a portion of the wing <NUM> to a portion of the fuselage <NUM>. In at least one example, the portion of the wing <NUM> is an underside <NUM> of the wing <NUM> that is aft (that is behind) in relation to a front edge <NUM>. The portion of the wing <NUM> can be between the front edge <NUM> and a rear edge (not shown in <FIG>). The portion of the fuselage <NUM> is fore (that is, in front) and below the wing <NUM>. As another example, the portion of the fuselage <NUM> can be above the wing <NUM>. As another example, the portion of the fuselage can be aft (that is, behind) and below or above the wing <NUM>.

The system <NUM> includes a longeron <NUM> having a longitudinal main body <NUM>. The main body <NUM> extends between a first end <NUM> and a second end <NUM> of the longeron <NUM>. The main body <NUM> can be a linear beam, rod, bar, and/or the like. The system <NUM> further includes a first moveable coupling interface <NUM> that moveably secures the first end <NUM> to the portion of the fuselage <NUM>, and a second moveable coupling interface <NUM> that moveably secures the second end <NUM> to the portion of the wing <NUM>.

In at least one embodiment, the first moveable coupling interface moveably secured in the first end <NUM> and the second moveable coupling interface moveably secured in the second end <NUM> are able to freely rotate in any direction. However, while the coupling interfaces are able to freely rotate, the coupling interfaces are axially constrained (that is, not able to axially shift or translate in any direction). Alternatively, the coupling interfaces can freely rotate and translate, at least to some extent.

In at least one example, the fuselage <NUM> includes a support fitting (such as a first support fitting) <NUM> that secures to the first moveable coupling interface <NUM>. In at least one example, the support fitting <NUM> includes at least a portion of the first moveable coupling interface <NUM>. Further, the wing <NUM> includes a support fitting (such as a second support fitting) <NUM> that secures to the second moveable coupling interface <NUM>. In at least one example, the supporting fitting <NUM> includes at least a portion of the second moveable coupling interface <NUM>.

In at least one example, the first moveable coupling interface <NUM> includes a spherical bearing moveably secured within a reciprocal bushing. For example, the first end <NUM> of the longeron <NUM> includes a clevis and/or lug that couples to the spherical bearing moveably retained within a reciprocal bushing secured to the support fitting <NUM>, or vice versa. As another example, the first end <NUM> includes the spherical bearing, and the support fitting <NUM> includes the reciprocal bushing, or vice versa. The spherical bearing is received and moveably retained within the bushing. In at least one example, the bushing is secured in position by a pin fastener, such as a bolt, lug, and/or the like. In at least one embodiment, the spherical bearing is integrally inside of a reciprocal bushing. The spherical bearing is installed in base material, just as the bushing is.

In at least one embodiment, the spherical bushing is installed on a lug side of a joint in a bore of a fitting lug, and bushings are installed in a clevis side of the joint in a bore of a fitting clevis. The lug can be on either the wing or fuselage attachment structure, or an underwing longeron member with the clevis on an opposing member of the joint. The spherical bearing is retained by the lug.

Further, as an example, the second moveable coupling interface <NUM> includes a spherical bearing moveably secured within a reciprocal bushing. For example, the second end <NUM> of the longeron <NUM> includes a clevis and/or lug that couples to the spherical bearing moveably retained within a reciprocal bushing secured to the support fitting <NUM>, or vice versa. As another example, the second end <NUM> of the longeron <NUM> includes the reciprocal bushing, and the support fitting <NUM> includes the spherical bearing, or vice versa. The spherical bearing is received and moveably retained within the bushing. In at least one example, the bushing is secured in position by a pin fastener, such as a bolt, lug, and/or the like.

The use of spherical bearings at the first moveable coupling interface <NUM> and the second moveable coupling interface <NUM> (that is, the two points of attachment) results in a two-force member under-wing longeron with subsequent load paths that are significantly simplified as compared to a traditional design. The system and method also reduce the amount of deflection induced loading on the longeron and supporting structures.

<FIG> illustrates a lateral view of the longeron <NUM> coupled to the portion of the fuselage <NUM>, according to an example of the subject disclosure. As an example, the support fitting <NUM> includes a flange <NUM> that includes a fastener opening <NUM> that receives a pin <NUM> (such as a bolt) that secures a bushing of the first moveable coupling interface <NUM> to the support fitting <NUM>.

<FIG> illustrates a schematic diagram of the system <NUM> for securing a portion of the wing <NUM> to a portion of the fuselage <NUM>, according to an example of the subject disclosure. In at least one example, the fuselage <NUM> includes a plurality of frames <NUM>. A backup support fitting <NUM> is secured between the frames <NUM>. The support fitting <NUM> extends outwardly from a frame <NUM>, such as the frame <NUM> closest to the wing <NUM>. The support fitting <NUM> can be integrally formed with the frame <NUM>, or separately secured to the frame <NUM>. A skin <NUM> is secured underneath the frames <NUM>.

A cheek panel <NUM> secures to the frame <NUM> closest to the wing <NUM> and a front spar <NUM> of the wing <NUM>. A lower panel <NUM> of the wing <NUM> connects below the front spar <NUM>. The support fitting <NUM> is secured below the cheek panel <NUM>.

As shown, the longeron <NUM> (such as an under-wing or over-wing longeron) extends between the portion of the fuselage <NUM> and the portion of the wing <NUM>. The first end <NUM> and the second end <NUM> are not rigidly fixed in position (that is, not constrained from moving) with respect to the fuselage <NUM> and the wing <NUM>. Instead, the first end <NUM> and the second end <NUM> are able to move through multiple degrees of freedom via the first moveable coupling interface <NUM> and the second moveable coupling interface <NUM>, respectively.

A length <NUM> of the longeron <NUM> between the first end <NUM> and the second end <NUM> is free. That is, the portion of the main body <NUM> between the first end <NUM> and the second end <NUM> (that is, the length <NUM> of the longeron <NUM>) is not fixed in position to either the fuselage <NUM> or the wing <NUM>, such as through fasteners. Instead, the length <NUM> of the longeron <NUM> is devoid of fasteners or other such structure that fixes the longeron <NUM> in place. The length <NUM> of the longeron <NUM> is free to move by way of the first moveable coupling interface <NUM> and the second moveable coupling interface <NUM>.

The first end <NUM> and the second end <NUM> include at least a portion of the first moveable coupling interface <NUM> and the second moveable coupling interface <NUM>, respectively. In at least one example, the portions of the first moveable coupling interface <NUM> and the second moveable coupling interface <NUM> are the first end <NUM> and the second end <NUM>. The first end <NUM> and the second end <NUM> are those portions that directly couple to reciprocal portions of the fuselage <NUM> and the wing <NUM>, such as through the reciprocal portions of the first moveable coupling interface <NUM> and the second moveable coupling interface <NUM>, respectively.

As indicated, the first moveable coupling interface <NUM> and the second moveable coupling interface <NUM> include spherical bearings. The spherical bearings allow for rotation about any axis, thereby eliminating or reducing induced moments due to deflection mismatch between the fuselage <NUM> and the wing <NUM>, while at the same time preserving the forward/aft load path through the longeron <NUM>. The bushings, such as eccentric bushings, allow build tolerances to be addressed by clocking of the bushings during installation. A final assembly operation includes clocking of bushings, installation of pins, clamp-up of joint, and installation retention features. No drilling operations are required, thereby reducing manufacturing time and costs.

In at least one embodiment, eccentric bushings can be used to adjust for build tolerances. The eccentric bushings can be installed in both prongs, ears, or the like of a clevis.

<FIG> illustrates a perspective end view of a spherical bearing <NUM> retained within a bushing <NUM>, according to an example of the subject disclosure. The spherical bearing <NUM> is rotatably retained within the bushing <NUM>. The bushing <NUM> can be secured to a support fitting <NUM>, such as the support fitting <NUM> or the support fitting <NUM> shown in <FIG>. Optionally, the bushing <NUM> can be secured to an end of the longeron <NUM>, such as the end <NUM> or <NUM>, such as shown in <FIG>.

<FIG> illustrates a perspective view of a moveable coupling interface <NUM>, according to an example of the subject disclosure. For the sake of clarity, portions of the moveable coupling interface <NUM> and the support fitting <NUM> are shown transparent. The moveable coupling interface <NUM> is an example of the first moveable coupling interface <NUM> or the second moveable coupling interface <NUM>, shown in <FIG>. In an example, the first end <NUM> (or the second end <NUM>) of the longeron <NUM> includes a clevis <NUM> that couples to one or both of the spherical bearing <NUM> and/or the bushing <NUM>.

Referring to <FIG>, the bushing <NUM> and/or the bearing <NUM> can include pin passages <NUM>. For example, the bushing <NUM> and the bearing <NUM> can include coaxial pin passages <NUM>. The pin passages <NUM> are configured to receive and retain one or more pins <NUM> (for example, a first pin <NUM> at one side, and a second pin <NUM> at an opposite side) that are configured to secure the moveable coupling interface <NUM> in place in relation to the fuselage <NUM> or the wing <NUM> (shown in <FIG>). In another example, the pins <NUM> are nested inside of bores of larger pins.

Optionally, the moveable coupling interface <NUM> may be sized, shaped and configured similarly or differently than shown. For example, the moveable coupling interface <NUM> can be a ball and socket connection.

<FIG> illustrates a flow chart of a method for securing a portion of a fuselage of an aircraft to a portion of a wing of the aircraft. The method includes moveably securing, at <NUM>, by a first moveable coupling interface, a first end of a longeron to the portion of the fuselage; and moveably securing, at <NUM>, by a second moveable coupling interface, a second end of the longeron to the portion of the wing. In at least one example, the method also includes securing a first support fitting of the fuselage to the first moveable coupling interface; and securing a second support fitting of the wing to the second moveable coupling interface. In at least one other embodiment, a sequence of installation is reversed from what is shown and described with respect to <FIG>.

As described herein, examples of the subject disclosure provide a longeron that is configured to readily adapt to forces exerted on and in relation to a fuselage and a wing. Further, examples of the subject disclosure provide a longeron that can be quickly and efficiently secured to a fuselage and a wing without the need for drilling operations, such as in the final assembly process of joining the fuselage to the wing, for example.

While various spatial and directional terms, such as top, bottom, lower, mid, lateral, horizontal, vertical, front and the like can be used to describe embodiments of the present disclosure, it is understood that such terms are merely used with respect to the orientations shown in the drawings.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) can be used in combination with each other. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the various embodiments of the disclosure without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various embodiments of the disclosure, the embodiments are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. In the appended claims and the detailed description herein, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein. " Moreover, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

Claim 1:
A system (<NUM>) for securing a portion of a fuselage of an aircraft to a portion of a wing of the aircraft, the system (<NUM>) comprising:
said wing (<NUM>);
said fuselage (<NUM>);
a longeron (<NUM>) having a first end (<NUM>) and a second end (<NUM>);
a first moveable coupling interface (<NUM>, <NUM>) for moveably securing the first end (<NUM>) of the longeron (<NUM>) to a portion of the
fuselage that is in front of and below the wing (<NUM>); and
a second moveable coupling interface (<NUM>, <NUM>) for moveably securing the second end (<NUM>) of the longeron (<NUM>) to an underside of the
wing that is aft in relation to a front edge of the wing (<NUM>),
wherein the fuselage (<NUM>) comprises a first support fitting (<NUM>) that secures to the first moveable coupling interface (<NUM>, <NUM>), and
wherein the wing comprises a second support fitting (<NUM>) that secures to the second moveable coupling interface (<NUM>, <NUM>).