Patent Description:
Generally, long span wings are desirable for commercial aircraft to increase aerodynamic efficiency when compared to wings having a shorter span. Increased aerodynamic efficiency reduces fuels consumption and may lead to reduced aircraft operating costs. The wingspan of an aircraft may be limited based on limits and/or regulations imposed by the International Civil Aviation Organization (ICAO), and/or based on physical infrastructure limitations of airports (e.g., the sizes of runways, taxiways, gate areas, hangars, etc.).

Foldable wings may be employed to reduce the wingspan of an aircraft when the aircraft is not in flight (e.g., when the aircraft is taxiing, parked, and/or stored). Such designs commonly include a foldable outboard section (e.g., a folding wing portion) of the wing that is hinged and/or rotatably coupled to an inboard section (e.g. a fixed wing portion) of the wing. The hinged and/or rotatably coupling enables movement of the foldable outboard section relative to the fixed inboard section between an unfolded position (e.g., a flight position) and a folded position (e.g. a stowed position). The foldable outboard section may be moved from the folded position to the unfolded position prior to takeoff of the aircraft to increase the wingspan of the aircraft. The foldable outboard section may conversely be moved from the unfolded position subsequent to landing of the aircraft to decrease the wingspan of the aircraft.

<CIT>, in accordance with its abstract, states a wing fold assembly for use in aircraft which provides relative rotational movement of a first wing tip about a second fixed wing including a plurality of wing tip flanges, and a plurality of fixed wing flanges wherein all of said flanges are rotatably mounted to a central shaft and wherein the improvement comprises means for selectively interlocking said wing tip flanges in relation to said fixed wing flanges to thereby lock said wing tip in position relative said fixed wing in either of a folded or faired position.

Accordingly, apparatuses and methods, intended to address at least one or more of the above-identified concerns, would find utility.

There is described herein a folding wing hinge for a wing having a fixed wing portion and a folding wing portion, the folding wing hinge comprising: a hinge pin including a hinge pin spline and having a first longitudinal axis; an input fitting coupled to one of the fixed wing portion and the folding wing portion, the input fitting including an input fitting spline and a second longitudinal axis; and a spline coupling member configured to couple with the hinge pin spline and the input fitting spline so that the first longitudinal axis is moveable relative to the second longitudinal axis by a first predetermined amount of movement; wherein the hinge pin spline is an external spline having teeth with a crowned tooth surface and the spline coupling member includes a first mating spline portion having an internal straight-sided spline configured to couple with the hinge pin spline; and wherein one of: a) the input fitting spline is an external spline having teeth with a crowned tooth surface and the spline coupling member includes a second mating spline portion having an internal straight-sided spline configured to couple with the input fitting spline, wherein the respective crowned tooth surfaces of each of the hinge pin spline and the input fitting spline form respective universal joints with the spline coupling member; and b) the input fitting spline is an internal straight-sided spline and the spline coupling member includes a second mating spline portion having teeth with a crowned tooth surface configured to couple with the input fitting spline, wherein crowned tooth surfaces of the hinge pin spline and tooth surfaces of the input fitting spline form respective universal joints with the spline coupling member.

The folding wing hinge may further comprise: at least one hinge pin bushing coupled to at least one of the fixed wing portion and the folding wing portion, the at least one hinge pin bushing having a third longitudinal axis; wherein the hinge pin extends through the at least one hinge pin bushing; and wherein the first longitudinal axis moves relative to the third longitudinal axis by a second predetermined amount of movement, the second predetermined amount of movement being less than the first predetermined amount of movement so that flight loads between the fixed wing portion and the folding wing portion are isolated or substantially isolated to a load path that passes through the at least one hinge pin bushing.

The input fitting may be coupled to the one of the fixed wing portion and the folding wing portion with a coupling that effects relative movement between the input fitting and the one of the fixed wing portion and the folding wing portion so that flight loads between the fixed wing portion and the folding wing portion are isolated or substantially isolated to a load path that passes through at least one hinge pin bushing coupled to at least one of the fixed wing portion and the folding wing portion, wherein the hinge pin extends through the at least one hinge pin bushing.

The folding wing hinge may further comprise: at least one hinge pin bushing coupled to at least one of the fixed wing portion and the folding wing portion, the at least one hinge pin bushing having a third longitudinal axis; and wherein the hinge pin extends through the at least one hinge pin bushing, and the input fitting includes a flanged end and a free end, the flanged end and the free end being separated by a longitudinal length that effects deflection of the free end, under flight loads, relative to the flanged end so that the first longitudinal axis of the hinge pin moves relative to the third longitudinal axis to isolate or substantially isolate flight loads between the fixed wing portion and the folding wing portion to a load path that passes through the at least one hinge pin bushing.

The respective crowned tooth surfaces of the hinge pin spline and the input fitting spline may have a radius of: between <NUM> inches (<NUM>) and <NUM> inches (<NUM>); or between about <NUM> inches (about <NUM>) and about <NUM> inches (about <NUM>).

The crowned tooth surface of the teeth of the second mating spline portion may have a radius of: between <NUM> inches (<NUM>) and <NUM> inches (<NUM>); or between about <NUM> inches (about <NUM>) and about <NUM> inches (about <NUM>).

The crowned tooth surface of the teeth of the hinge pin spline may have a radius of: between <NUM> inches (<NUM>) and <NUM> inches (<NUM>); or between about <NUM> inches (about <NUM>) and about <NUM> inches (about <NUM>).

There is also described herein an aircraft comprising: a wing having a fixed wing portion and a folding wing portion; and the folding wing hinge described above.

The first longitudinal axis may be parallel or substantially parallel with a fuselage of the aircraft.

The first longitudinal axis of the hinge pin may be perpendicular or substantially perpendicular to at least one spar of the fixed wing portion.

There is also described herein a method for substantially isolating flight loads in a folding wing hinge, the method comprising: providing an input fitting that is coupled to one of a fixed wing portion and a folding wing portion of a wing, wherein the input fitting includes an input fitting spline coupled with a hinge pin spline of a hinge pin; effecting relative movement between a first longitudinal axis of the hinge pin and a second longitudinal axis of the input fitting with a spline coupling member configured to couple with the hinge pin spline and the input fitting spline so that the first longitudinal axis moves relative to the second longitudinal axis by a first predetermined amount of movement; effecting relative movement between the first longitudinal axis of the hinge pin and the second longitudinal axis of the input fitting wherein the hinge pin spline is an external spline having teeth with a crowned tooth surface and the spline coupling member includes a first mating spline portion having an internal straight-sided spline; and one of: a) effecting relative movement between the first longitudinal axis of the hinge pin and the second longitudinal axis of the input fitting wherein the input fitting spline is an external spline having teeth with a crowned tooth surface, and wherein the spline coupling member includes a second mating spline portion having an internal straight-sided spline configured to couple with the input fitting spline; and b) effecting relative movement between the first longitudinal axis of the hinge pin and the second longitudinal axis of the input fitting wherein the input fitting spline is an internal linear spline and the spline coupling member includes a second mating spline portion having teeth with a crowned tooth surface configured to couple with the input fitting spline.

The method may further comprise isolating or substantially isolating flight loads between the fixed wing portion and the folding wing portion to a load path that passes through at least one hinge pin bushing coupled to at least one of the fixed wing portion and the folding wing portion; and wherein the at least one hinge pin bushing has a third longitudinal axis, and the hinge pin extends through the at least one hinge pin bushing; and wherein the first longitudinal axis of the hinge pin moves relative to the third longitudinal axis by a second predetermined amount of movement, the second predetermined amount of movement being less than the first predetermined amount of movement.

The method may further comprise effecting relative movement between the input fitting and the one of the fixed wing portion and the folding wing portion so that flight loads between the fixed wing portion and the folding wing portion are isolated or substantially isolated to a load path that passes through at least one hinge pin bushing coupled to at least one of the fixed wing portion and the folding wing portion, where the hinge pin extends through the at least one hinge pin bushing.

The method may further comprise effecting deflection of a free end of the input fitting relative to a flanged end of the input fitting with a longitudinal length of the input fitting separating the free end from the flanged end so that the first longitudinal axis of the hinge pin moves relative to a third longitudinal axis of at least one hinge pin bushing coupled to at least one of the fixed wing portion and the folding wing portion to isolate or substantially isolate flight loads between the fixed wing portion and the folding wing portion to a load path that passes through the at least one hinge pin bushing.

Having thus described examples of the present disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein like reference characters designate the same or similar parts throughout the several views, and wherein:.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, the aircraft <NUM> includes a wing <NUM> having a folding wing portion <NUM> rotatably coupled to a fixed wing portion <NUM> by a folding wing hinge <NUM>. The folding wing hinge <NUM> includes one or more hinge pins <NUM>, <NUM>, <NUM> installed along a hinge axis <NUM>. In some examples of the present disclosure the folding wing hinge <NUM> includes three hinge pins <NUM>, <NUM>, <NUM> but in other examples the folding wing hinge <NUM> may have more or less than three hinge pins. Each of the hinge pins <NUM>, <NUM>, <NUM> transfer flight loads <NUM> (see <FIG>) from the folding wing portion <NUM> to the fixed wing portion <NUM>. In addition to transferring the flight loads, at least one of the hinge pins, such as hinge pin <NUM>, reacts or transfers torsional loads <NUM> (see <FIG>) associated with folding and unfolding of the folding wing portion <NUM> relative to the fixed wing portion <NUM>.

The folding wing hinge <NUM>, in accordance with some examples of the present disclosure, may isolate or substantially isolate the flight loads <NUM> (see <FIG>) transferred between the folding wing portion <NUM> and a fixed wing portion <NUM> of the wing <NUM> from torsional loads <NUM> (see <FIG>) associated with folding and unfolding the folding wing portion <NUM> relative to the fixed wing portion <NUM>. Examples of the present disclosure may provide for a single hinge pin <NUM> that reacts or transfers both the flight loads <NUM> and the torsional loads <NUM> without a decrease in service life of the hinge pin <NUM> or substantially without a decrease in service life of the hinge pin <NUM>.

Illustrative, non-exhaustive examples, which may or may not be claimed, of the subject matter according to the present disclosure are provided below.

In accordance with some examples of the present disclosure, referring to <FIG>, the aircraft <NUM> is illustrated as a commercial passenger aircraft but in other examples the aircraft <NUM> may be any suitable aircraft including general aviation aircraft, military aircraft, flying automobiles, or any other aircraft having a portion of a wing that folds as described herein. The aircraft <NUM> includes a fuselage <NUM> and a wing <NUM> coupled to the fuselage <NUM>. Referring also to <FIG>, <FIG>, <FIG>, <FIG>, the wing <NUM> includes a fixed wing portion <NUM> that is coupled to the fuselage <NUM> so as to have a fixed orientation relative to the fuselage <NUM> (while the fixed wing portion is described as having a fixed orientation relative to the fuselage, in other aspects the fixed wing portion may be a variable sweep wing). The wing <NUM> also includes a folding wing portion <NUM> that is rotatably coupled to the fixed wing portion <NUM> by the folding wing hinge <NUM> so as to be selectively positioned between an unfolded position <NUM> (see <FIG> - (e.g., the flight position)) and a folded position <NUM> (see <FIG> - (e.g., the stowed position)). The folding wing portion <NUM> may have a swept or raked wing configuration <NUM> (as illustrated in <FIG>), a constant chord configuration <NUM>, a tapered configuration <NUM>, a reverse tapered configuration <NUM>, an elliptical configuration <NUM>, a semi-elliptical configuration <NUM> or any combination thereof.

In some examples, the folding wing hinge <NUM> is coupled to or at least partially formed by the fixed wing portion <NUM> so that the hinge axis <NUM> (and longitudinal axis <NUM> of hinge pin <NUM> described herein) extends in a direction that is parallel or substantially parallel with a centerline <NUM> of the fuselage <NUM> (see <FIG>); while in other examples, the folding wing hinge <NUM> is coupled to or at least partially formed by the fixed wing portion <NUM> so that the hinge axis <NUM> (and longitudinal axis <NUM> of hinge pin <NUM> described herein) extends in a direction that is perpendicular or substantially perpendicular to the spar <NUM> of the fixed wing portion <NUM> (See <FIG>). In still other examples, the hinge axis <NUM> may have any suitable spatial orientation relative to one or more of the fuselage <NUM> and fixed wing portion <NUM>.

Referring also to <FIG> and <FIG>, the folding wing hinge <NUM> rotatably couples the fixed wing portion <NUM> to the folding wing portion <NUM> (the fixed wing portion <NUM> and the folding wing portion <NUM> being demarcated by the dashed line <NUM>). The fixed wing portion <NUM> includes any suitable number of fixed hinge knuckles <NUM>, <NUM>, <NUM>, <NUM>. The folding wing portion <NUM> includes any suitable corresponding number of folding hinge knuckles <NUM>, <NUM>, <NUM>, <NUM> that are interdigitated with the fixed hinge knuckles <NUM>, <NUM>, <NUM>, <NUM>. The hinge pins <NUM>, <NUM>, <NUM> extend through respective ones of the fixed hinge knuckles <NUM>, <NUM>, <NUM>, <NUM> and the folding hinge knuckles <NUM>, <NUM>, <NUM>, <NUM> so as to rotatably couple the fixed wing portion <NUM> and the folding wing portion <NUM>. For exemplary purposes only, hinge pin <NUM> extends through fixed hinge knuckle <NUM> and folding hinge knuckle <NUM>, hinge pin <NUM> extends through fixed hinge knuckle <NUM> and folding hinge knuckle <NUM>, and hinge pin <NUM> extends through fixed hinge knuckles <NUM>, <NUM> and folding hinge knuckles <NUM>, <NUM>. <FIG> is similar or substantially similar to <FIG> however, in <FIG>, hinge pin <NUM> extends through fixed hinge knuckle <NUM> and folding hinge knuckle <NUM>, hinge pin <NUM> extends through fixed hinge knuckle <NUM> and folding hinge knuckle <NUM>, and hinge pin <NUM> extends through fixed hinge knuckles <NUM>, <NUM> and folding hinge knuckles <NUM>, <NUM>. In <FIG>, hinge pin <NUM> extends through fixed hinge knuckle <NUM> and folding hinge knuckle <NUM>, hinge pin <NUM> extends through fixed hinge knuckle <NUM> and folding hinge knuckle <NUM>, and hinge pin <NUM> extends through fixed hinge knuckles <NUM>, <NUM> and folding hinge knuckles <NUM>, <NUM>.

Referring to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, the hinge pin <NUM> is fixedly coupled to the fixed wing portion <NUM>, e.g., so that the hinge pin <NUM> does not rotate relative to the fixed wing portion <NUM>. In <FIG>, the hinge pin <NUM> is fixedly coupled to the folding wing portion <NUM>, otherwise the operation and structure of the folding wing hinge <NUM> is similar or substantially similar between the examples illustrated in <FIG>. Here, the folding wing hinge includes the hinge pin <NUM>, an input fitting <NUM>, and a spline coupling member <NUM>, where in <FIG> and <FIG> the input fitting <NUM> and spline coupling member <NUM> non-rotatably couple the hinge pin <NUM> to, for example, the fixed hinge knuckle <NUM> of the fixed wing portion <NUM>. In <FIG>, the input fitting <NUM> and spline coupling member <NUM> non-rotatably couple the hinge pin <NUM> to, for example, the folding hinge knuckle <NUM> of the folding wing portion <NUM>. The positions of the hinge pin <NUM>, the input fitting <NUM>, and the spline coupling member <NUM> (and the rotary actuator <NUM> coupled to the hinge pin <NUM>) illustrated in <FIG> are exemplary only and in other examples, the hinge pin <NUM> may be fixedly coupled to any suitable portion of one of the fixed wing portion <NUM> and the folding wing portion <NUM> where the rotary actuator <NUM> is disposed within (and coupled to) the other one of the fixed wing portion <NUM> and the folding wing portion <NUM>.

In some examples, the hinge pin <NUM> includes a hinge pin spline <NUM> and a first longitudinal axis <NUM>. The input fitting <NUM> is coupled to one of the fixed wing portion <NUM> and the folding wing portion <NUM>. In the aspects illustrated in <FIG>, <FIG>, and <FIG> the input fitting <NUM> is coupled to the fixed wing portion <NUM>; while in other aspects, such as illustrated in <FIG>, the input fitting <NUM> is coupled to the folding wing portion <NUM>. The input fitting <NUM> includes an input fitting spline <NUM> and a second longitudinal axis <NUM>. The spline coupling member <NUM> has a spline coupling member <NUM> configured to couple with the hinge pin spline <NUM> and the input fitting spline <NUM> so that the first longitudinal axis <NUM> moves relative to the second longitudinal axis <NUM> by a first predetermined amount of movement <NUM> (see <FIG>), where the amount of movement is a linear distance <NUM> and/or an angular rotation <NUM> as shown in <FIG>. The spline coupling member <NUM> includes a first mating spline portion <NUM> that couples with the hinge pin spline <NUM> and a second mating spline portion <NUM> that couples with the input fitting spline <NUM>. In some examples, the spline coupling member <NUM> may couple with both the hinge pin spline <NUM> and the input fitting spline <NUM> with spline teeth that are common to both the hinge pin spline <NUM> and the input fitting spline <NUM>. The hinge pin spline <NUM>, the input fitting spline <NUM> and the spline(s) of the coupling member <NUM> may be involute splines, square splines (e.g., having parallel or substantially parallel sides) or any other suitable spline. Referring to <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, the hinge pin spline <NUM> is an external spline <NUM> having teeth <NUM> with a crowned tooth surface <NUM>. The crowned tooth surface <NUM> includes one or more of the sides <NUM>, <NUM> of a respective tooth <NUM> and a top land or outer/top surface <NUM> of the respective tooth <NUM>. With respect to the sides <NUM>, <NUM>, the crowned tooth surface <NUM> is such that, a distance <NUM> between the sides <NUM>, <NUM> at longitudinal ends <NUM>, <NUM> of the respective tooth <NUM> is less than a distance <NUM> at a center portion <NUM> of the respective tooth <NUM>. The difference in the distances <NUM>, <NUM> is effected by a curvature of the respective sides (see <FIG>), where respective sides have a radius <NUM> of between about <NUM> inches (about <NUM>) and about <NUM> inches (about <NUM>). In other examples, the radius <NUM> may be more than about <NUM> inches (about <NUM>) or less than about <NUM> inches (about <NUM>). It is noted that the differences in tooth thickness effected by the distances <NUM>, <NUM> may be apparent when measured from a constant/common reference datum (i.e., a location from which all measurements of the tooth are based) of the part on which the teeth are disposed. For example, with respect to the hinge pin spline <NUM> of hinge pin <NUM>, the difference in the distances <NUM>, <NUM> and the resulting changes in tooth thickness between the sides <NUM>, <NUM> (i.e., the tooth growing thicker at its center portion <NUM> between the longitudinal ends <NUM>, <NUM>) are apparent when the distances <NUM>, <NUM> are measured from the first longitudinal axis <NUM> (or a constant/common distance from the first longitudinal axis) of the hinge pin <NUM>, where the first longitudinal axis <NUM> forms a centerline of the hinge pin <NUM>.

With respect to the outer surface <NUM> of the respective tooth <NUM>, the crowned tooth surface <NUM> is such that, a distance <NUM> between the outer surface <NUM> and the centerline of the part on which the tooth <NUM> is disposed (e.g., such as the first longitudinal axis <NUM> of the hinge pin <NUM>) (see <FIG>) at the longitudinal ends <NUM>, <NUM> of the respective tooth <NUM> is less than a distance <NUM> between the outer surface <NUM> and the first longitudinal axis <NUM> at the center portion <NUM> of the respective tooth <NUM>. The difference in the distances <NUM>, <NUM> is effected by a curvature of the outer surface <NUM> (see <FIG>), where outer surface <NUM> has a radius <NUM> of between about <NUM> inches (about <NUM>) and about <NUM> inches (about <NUM>). In other examples, the radius <NUM> may be more than about <NUM> inches (about <NUM>) or less than about <NUM> inches (about <NUM>). The first mating spline portion <NUM> of the spline coupling member <NUM> has an internal straight-sided spline <NUM> (e.g., having linear or un-crowned spline teeth <NUM> with tooth surfaces <NUM> - <FIG>).

Still referring to <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, the input fitting spline <NUM> is an external spline <NUM> having teeth <NUM> (<FIG>) with a crowned tooth surface <NUM> (<FIG> and <FIG>) that is similar or substantially similar to the crowned tooth surface <NUM> of the hinge pin spline <NUM> (see <FIG>) described above. For example, with respect to the sides <NUM>, <NUM>, the crowned tooth surface <NUM> is such that, a distance <NUM> between the sides <NUM>, <NUM> at longitudinal ends <NUM>, <NUM> of the respective tooth <NUM> is less than a distance <NUM> at a center portion <NUM> of the respective tooth <NUM>. The difference in the distances <NUM>, <NUM> is effected by a curvature of the respective sides (see <FIG>), where respective sides have a radius <NUM> of between about <NUM> inches (about <NUM>) and about <NUM> inches (about <NUM>). In other examples, the radius <NUM> may be more than about <NUM> inches (about <NUM>) or less than about <NUM> inches (about <NUM>). Again, with respect to the input fitting spline <NUM>, the difference in the distances <NUM>, <NUM> and the resulting changes in tooth thickness between the sides <NUM>, <NUM> (i.e., the tooth growing thicker at its center portion <NUM> between the longitudinal ends <NUM>, <NUM>) are apparent when the distances <NUM>, <NUM> are measured from the second longitudinal axis <NUM> (or a constant/common distance from the second longitudinal axis) of the input fitting <NUM>, where the second longitudinal axis <NUM> forms a centerline of the input fitting <NUM>.

With respect to the outer surface <NUM> of the respective tooth <NUM>, the crowned tooth surface <NUM> is such that, the distance <NUM> between the outer surface <NUM> and the second longitudinal axis <NUM> at the longitudinal ends <NUM>, <NUM> of the respective tooth <NUM> is less than a distance <NUM> between the outer surface <NUM> and the second longitudinal axis <NUM> at the center portion <NUM> of the respective tooth <NUM>. The difference in the distances <NUM>, <NUM> is effected by a curvature of the outer surface <NUM> (see <FIG>), where outer surface <NUM> has a radius <NUM> of between about <NUM> inches (about <NUM>) and about <NUM> inches (about <NUM>). In other examples, the radius <NUM> may be more than about <NUM> inches (about <NUM>) or less than about <NUM> inches (about <NUM>). The second mating spline portion <NUM> of the spline coupling member <NUM> has an internal straight-sided spline <NUM> (see <FIG> and <FIG> - e.g., having linear or un-crowned spline teeth <NUM>). It is noted that where the spline coupling member <NUM> includes a crowned spline, the crowned spline of the spline coupling member <NUM> is similar or substantially similar to that described above with respect to the input fitting <NUM> and the hinge pin <NUM>.

With respect to the relationship between the radius <NUM> and the radius <NUM> of the input fitting <NUM>, the hinge pin <NUM>, and the spline coupling member <NUM>, the crowned spline has constant profile teeth, where each tooth follows a curved path <NUM> having the radius <NUM>. As a result of each tooth following the curved path <NUM> having the radius <NUM>, the crowned sides <NUM>, <NUM> have an effective radius <NUM> when that radius <NUM> is measured from the reference datum described above.

Referring to <FIG>, in some examples, the hinge pin spline <NUM> is an external spline having teeth <NUM> with a crowned tooth surface <NUM> as described above. In these examples, the input fitting spline 705A is an internal straight-sided spline 709A having straight un-crowned teeth 810A (similar or substantially similar to teeth <NUM> described herein with tooth surfaces <NUM>). The first mating spline portion <NUM> of the spline coupling member <NUM> is as described above however, the second mating spline portion 712A has teeth <NUM>, each having a crowned tooth surface <NUM> that is similar or substantially similar to crowned tooth surfaces <NUM>, <NUM>.

Referring also to <FIG>, the respective crowned tooth surfaces <NUM>, <NUM> of each of the hinge pin spline <NUM> and the input fitting spline <NUM> form respective universal joints <NUM>, <NUM> (e.g., splined universal joints) with the spline coupling member <NUM>. In some examples, such as in <FIG>, where crowned tooth surface <NUM> is employed, the crowned tooth surface <NUM> also forms a universal joint <NUM> with the spline coupling member <NUM> similar or substantially similar to universal joints <NUM>, <NUM>. The universal joint <NUM>, <NUM>, <NUM> (e.g., splined universal joint) as used herein is a joint that provides two degree of freedom pivoting motion in directions <NUM>, <NUM> (see <FIG>) between two shafts (e.g., such as between the hinge pin <NUM> and the spline coupling member <NUM> and between the spline coupling member <NUM> and the input fitting <NUM>) while also providing a splined coupling between the shafts. For example, the crowned tooth surfaces <NUM>, <NUM>, <NUM>, as described above, provide increasing clearance between each of the hinge pin spline <NUM> and the input fitting spline <NUM> with a respective one of the first mating spline portion <NUM> and the second mating spline portion <NUM> of the spline coupling member <NUM>, where the clearance increases from the center portion <NUM> of the teeth <NUM>, <NUM>, <NUM> towards the longitudinal ends <NUM>, <NUM> of the teeth <NUM>, <NUM>. This clearance provides for relative pivoting movement between the hinge pin spline <NUM> and the first mating spline portion <NUM> about a contact area <NUM> (<FIG> - shown with respect to teeth <NUM> for illustrative purposes only noting a similar contact area is provided with teeth <NUM>, <NUM>) formed between the crowned sides <NUM>, <NUM> of the teeth <NUM>, <NUM>, <NUM> and mating spline tooth surfaces <NUM>, <NUM>.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, at least one hinge pin bushing <NUM>, <NUM> (see in <FIG> with respect to hinge pin <NUM>, noting similar hinge pin bushings may be provided for hinge pins <NUM>, <NUM>) is coupled to at least one of the fixed wing portion <NUM> and the folding wing portion <NUM>. In <FIG>, hinge pin bushing <NUM> is coupled to the fixed wing portion <NUM> and hinge pin bushing <NUM> is coupled to the folding wing portion <NUM>. The hinge pin <NUM> extends through the at least one hinge pin bushing <NUM>, <NUM> so that the hinge pin <NUM> is supported by the at least one hinge pin bushing <NUM>, <NUM> about a third longitudinal axis <NUM> of the at least one hinge pin bushing <NUM>, <NUM>. The first longitudinal axis <NUM> moves relative to the third longitudinal axis <NUM> by a second predetermined amount of movement <NUM> (shown as a linear distance in <FIG> but may be a linear rotation in addition to or in lieu of the linear distance). The second predetermined amount of movement <NUM> is less than the first predetermined amount of movement <NUM> so that flight loads <NUM> between the fixed wing portion <NUM> and the folding wing portion <NUM> are isolated or substantially isolated to a load path <NUM> that passes through the at least one hinge pin bushing <NUM>. The coupling between the spline coupling member <NUM> and both of the hinge pin <NUM> and input fitting <NUM> is configured to decouple the flight loads <NUM> between the fixed wing portion <NUM> and the folding wing portion <NUM> (e.g., prevents or substantially prevents flight loads from passing through the hinge pin spline <NUM>, the input fitting spline <NUM> and the spline coupling member <NUM>).

As illustrated in <FIG>, the splined coupling (e.g., crowned spline coupling) between the hinge pin <NUM> and the spline coupling member <NUM> provides for axial misalignment between the hinge pin <NUM> and the spline coupling member <NUM> such that the first longitudinal axis <NUM> and a coupling member longitudinal axis <NUM> can pivot relative to one another in directions <NUM>, <NUM> (<FIG>). Similarly, the splined coupling (e.g., crowned spline coupling) between the input fitting <NUM> and the spline coupling member <NUM> provides for axial misalignment between the input fitting <NUM> and the spline coupling member <NUM> such that the second longitudinal axis <NUM> and the coupling member longitudinal axis <NUM> can pivot relative to one another in directions <NUM>, <NUM> (<FIG>). Here, two sets of crowned spline couplings (e.g., the first set between the input fitting <NUM> and the spline coupling member <NUM> and the second set between the spline coupling member <NUM> and the hinge pin <NUM>) provides for "floating" of the hinge pin <NUM> relative to the input fitting <NUM>.

The crowned spline couplings provide for a greater amount of movement (e.g. translation in directions <NUM>, <NUM>) between the hinge pin <NUM> and the input fitting <NUM> than allowed between the at least one hinge pin bushing <NUM>, <NUM> and the hinge pin <NUM> such that contact is made between the hinge pin <NUM> and the at least one hinge pin bushing <NUM>, <NUM> before the crowned spline couplings reach their limits of motion thereby decoupling (e.g., isolating) the torsional loads <NUM> transmitted through the crowned spline couplings for folding/unfolding the folding wing portion <NUM> from the flight loads <NUM>. The crowned splined couplings as described herein may also ease manufacturing tolerances because the relative movement between the hinge pin <NUM> and the input fitting <NUM> provides for relaxed position accuracy when locating the input fitting relative to the hinge axis <NUM> (which may be defined by, e.g., the third longitudinal axis <NUM> of the hinge pin bushings at least one hinge pin bushing <NUM>, <NUM>).

To prevent or substantially prevent movement of the spline coupling member <NUM> along the first longitudinal axis <NUM> and/or second longitudinal axis <NUM>, the hinge pin <NUM> includes a first protrusion <NUM> (<FIG> and <FIG>) configured to prevent longitudinal movement of the spline coupling member <NUM> relative to the hinge pin <NUM> in a first longitudinal direction <NUM>. The input fitting <NUM> includes a second protrusion <NUM> (<FIG> and <FIG>) configured to prevent longitudinal movement of the spline coupling member <NUM> relative to the hinge pin <NUM> in a second longitudinal direction <NUM>, the second longitudinal direction <NUM> being opposite the first longitudinal direction <NUM>.

As described above, rotary actuator <NUM> is coupled to the hinge pin <NUM> to effect folding and unfolding of the folding wing portion <NUM> relative to the fixed wing portion <NUM>. The coupling between the rotary actuator and the hinge pin <NUM> may be any suitable coupling such as a spline coupling <NUM>. While the input fitting <NUM> is coupled to one of the fixed wing portion <NUM> and the folding wing portion <NUM>, the rotary actuator <NUM> is coupled to another of the fixed wing portion <NUM> and the folding wing portion <NUM> (e.g., where the input fitting <NUM> is coupled to the fixed wing portion <NUM> the rotary actuator <NUM> is coupled to the folding wing portion <NUM> and where input fitting <NUM> is coupled to the folding wing portion <NUM> the rotary actuator <NUM> is coupled to the fixed wing portion <NUM>) so as to provide relative rotation between the hinge pin <NUM> and the rotary actuator <NUM>.

Referring also to <FIG>, which shows an example not according to the claims, in addition to (or in lieu of) the crowned splined couplings describe above, the folding wing hinge <NUM> may be provided with additional features that may provide for movement of one or more of the hinge pin <NUM> and the input fitting <NUM> relative to the at least one hinge pin bushing <NUM>, <NUM> for decoupling the flight loads <NUM> (<FIG>) and the torsional loads <NUM> (<FIG>) such that the flight loads are directed through the load path <NUM> (<FIG>) rather than through the splined coupling between the hinge pin <NUM> and the input fitting <NUM>. In some examples, the input fitting <NUM> is coupled to the one of the fixed wing portion <NUM> and the folding wing portion <NUM> with a coupling <NUM> that effects relative movement (e.g., in directions <NUM>, <NUM> - <FIG>) between the input fitting <NUM> and the one of the fixed wing portion <NUM> and the folding wing portion <NUM> so that the flight loads <NUM> (<FIG>) between the fixed wing portion <NUM> and the folding wing portion <NUM> are isolated or substantially isolated to the load path <NUM> (<FIG>) that passes through the at least one hinge pin bushing <NUM>, <NUM> coupled to at least one of the fixed wing portion <NUM> and the folding wing portion <NUM>, wherein the hinge pin <NUM> extends through the at least one hinge pin bushing <NUM>, <NUM>. For example, the input fitting <NUM> and/or one of the fixed wing portion <NUM> and the folding wing portion <NUM> may have a fastener aperture <NUM> that is larger than a diameter of a fastener <NUM> coupling the input fitting <NUM> to the one of the fixed wing portion <NUM> and the folding wing portion <NUM>. The fastener aperture <NUM> may be sized relative to the fastener <NUM> and/or the fastener <NUM> may be tightened to a predetermined torque specification that provides for relative movement between the input fitting <NUM> and the one of the fixed wing portion <NUM> and the folding wing portion <NUM> where the relative movement is greater than the second predetermined amount of movement <NUM> between the hinge pin <NUM> and the at least one hinge pin bushing <NUM>, <NUM> so that the first longitudinal axis <NUM> of the hinge pin <NUM> moves relative to the third longitudinal axis <NUM> of the at least one hinge pin bushing <NUM>, <NUM> to isolate or substantially isolate the flight loads <NUM> between the fixed wing portion <NUM> and the folding wing portion <NUM> to the load path <NUM> that passes through the at least one hinge pin bushing <NUM>, <NUM>.

Still referring to <FIG>, in some examples, the input fitting <NUM> includes a flanged end <NUM> and a free end <NUM>, where the flanged end <NUM> and the free end <NUM> are separated by a longitudinal length <NUM> that effects deflection of the free end <NUM> under flight loads <NUM> relative to the flanged end <NUM> so that the first longitudinal axis <NUM> of the hinge pin <NUM> moves relative to the third longitudinal axis <NUM> of the at least one hinge pin bushing <NUM>, <NUM> to isolate or substantially isolate the flight loads <NUM> between the fixed wing portion <NUM> and the folding wing portion <NUM> to the load path <NUM> that passes through the at least one hinge pin bushing <NUM>, <NUM>. In still other examples, a tooth-to-tooth interface <NUM> of one or more of the hinge pin spline <NUM> and the input fitting spline <NUM>, 705A with the spline coupling member <NUM> effects a third predetermined amount of movement <NUM> (<FIG>) between teeth of the spline coupling member <NUM> and teeth of one or more of the hinge pin spline <NUM> and the input fitting spline <NUM>, 705A. Here, the second predetermined amount of movement <NUM> is less than the third predetermined amount of movement <NUM> so that the flight loads <NUM> (<FIG>) between the fixed wing portion <NUM> and the folding wing portion <NUM> are isolated or substantially isolated to the load path <NUM> that passes through the at least one hinge pin bushing <NUM>, <NUM>. For example, clearance <NUM> (corresponding to the third predetermined amount of movement <NUM>) may be provided between the teeth <NUM> (which may be straight teeth or crowned teeth as described above) of the input fitting spline <NUM> (which may be an internal or external spline, where an internal spline is illustrated in <FIG> for exemplary purposes only) and the teeth <NUM> (which may be straight teeth or crowned teeth as described above) of the hinge pin spline <NUM> (which may be an internal or external spline, where an external spline is illustrated in <FIG> for exemplary purposes only). Here the clearance <NUM> may be greater than the second predetermined amount of movement <NUM> between the hinge pin <NUM> and the at least one hinge pin bushing <NUM>, <NUM> so that the first longitudinal axis <NUM> of the hinge pin <NUM> moves relative to the third longitudinal axis <NUM> of the at least one hinge pin bushing <NUM>, <NUM> to isolate or substantially isolate the flight loads <NUM> between the fixed wing portion <NUM> and the folding wing portion <NUM> to the load path <NUM> that passes through the at least one hinge pin bushing <NUM>, <NUM>.

Referring now to at least <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, an exemplary method for isolating or substantially isolating flight loads <NUM> in the folding wing hinge <NUM> will be described. The method includes providing an input fitting <NUM> that is coupled to one of a fixed wing portion <NUM> and a folding wing portion <NUM> of a wing <NUM> (<FIG>, Block <NUM>), wherein the input fitting <NUM> includes an input fitting spline <NUM>, 705A coupled with a hinge pin spline <NUM> of a hinge pin <NUM>. Relative movement is effected between a first longitudinal axis <NUM> of the hinge pin <NUM> and a second longitudinal axis <NUM> of the input fitting <NUM> with a spline coupling member <NUM> having a spline coupling member <NUM> configured to couple with the hinge pin spline <NUM> and the input fitting spline <NUM>, 705A so that the first longitudinal axis <NUM> moves relative to the second longitudinal axis <NUM> by a first predetermined amount of movement <NUM> (<FIG>).

The flight loads <NUM> between the fixed wing portion <NUM> and the folding wing portion <NUM> are isolated or substantially isolated to the load path <NUM> that passes through at least one hinge pin bushing <NUM>, <NUM> coupled to at least one of the fixed wing portion <NUM> and the folding wing portion <NUM> (<FIG>, Block <NUM>). For example, the at least one hinge pin bushing <NUM>, <NUM> has a third longitudinal axis <NUM> and the first longitudinal axis <NUM> of the hinge pin <NUM> moves relative to the third longitudinal axis <NUM> by the second predetermined amount of movement <NUM>. In another example, relative movement between the input fitting <NUM> and the one of the fixed wing portion <NUM> and the folding wing portion <NUM> is effected so that flight loads <NUM> between the fixed wing portion <NUM> and the folding wing portion <NUM> are isolated or substantially isolated to the load path <NUM> that passes through at least one hinge pin bushing <NUM>, <NUM> coupled to at least one of the fixed wing portion <NUM> and the folding wing portion <NUM>, where the hinge pin <NUM> extends through the at least one hinge pin bushing <NUM>, <NUM>. In some examples, the flight loads <NUM> are decoupled between the fixed wing portion <NUM> and the folding wing portion <NUM> with the coupling between the spline coupling member <NUM> and both of the hinge pin <NUM> and input fitting <NUM> (<FIG>, Block <NUM>). In other examples, deflection of the free end <NUM> of the input fitting <NUM> is effected relative to the flanged end <NUM> of the input fitting <NUM> (<FIG>, Block <NUM>) with the longitudinal length <NUM> of the input fitting <NUM> so that the first longitudinal axis <NUM> of the hinge pin <NUM> moves relative to the third longitudinal axis <NUM> of the at least one hinge pin bushing <NUM>, <NUM> to isolate or substantially isolate flight loads <NUM> between the fixed wing portion <NUM> and the folding wing portion <NUM> to the load path <NUM>.

The method may also include preventing longitudinal movement of the spline coupling member <NUM> relative to the hinge pin <NUM> in the first longitudinal direction <NUM> with the first protrusion <NUM> of the hinge pin <NUM>. Longitudinal movement of the spline coupling member <NUM> relative to the hinge pin <NUM> may also be prevented in the second longitudinal direction <NUM>, the second longitudinal direction <NUM> being opposite the first longitudinal direction <NUM>, with the second protrusion <NUM> of the input fitting <NUM>.

The method may also include effecting the third predetermined amount of movement <NUM> (<FIG>), with a tooth-to-tooth interface <NUM> of one or more of the hinge pin spline <NUM> and the input fitting spline <NUM>, 705A with the spline coupling member <NUM>, between teeth of the spline coupling member <NUM> and teeth of the one or more of the hinge pin spline <NUM> and the input fitting spline <NUM>, 705A, wherein the second predetermined amount of movement <NUM> between the hinge pin <NUM> and at least one hinge pin bushing <NUM>, <NUM> coupled to at least one of the fixed wing portion <NUM> and the folding wing portion <NUM> is less than the third predetermined amount of movement <NUM> so that flight loads <NUM> between the fixed wing portion <NUM> and the folding wing portion <NUM> are isolated or substantially isolated to the load path <NUM>. As used herein, "coupled" means associated directly as well as indirectly. For example, a member A may be directly associated with a member B, or may be indirectly associated therewith, e.g., via another member C. It will be understood that not all relationships among the various disclosed elements are necessarily represented. Accordingly, couplings other than those depicted in the drawings may also exist. Dashed lines, if any, connecting blocks designating the various elements and/or components represent couplings similar in function and purpose to those represented by solid lines; however, couplings represented by the dashed lines may either be selectively provided or may relate to alternative examples of the present disclosure. Likewise, elements and/or components, if any, represented with dashed lines, indicate alternative examples of the present disclosure. One or more elements shown in solid and/or dashed lines may be omitted from a particular example without departing from the scope of the present disclosure. Environmental elements, if any, are represented with dotted lines. Virtual (imaginary) elements may also be shown for clarity. Those skilled in the art will appreciate that some of the features illustrated in the figures, may be combined in various ways without the need to include other features described in the figures, other drawing figures, and/or the accompanying disclosure, even though such combination or combinations are not explicitly illustrated herein. Similarly, additional features not limited to the examples presented, may be combined with some or all of the features shown and described herein.

In <FIG>, referred to above, the blocks may represent operations and/or portions thereof and lines connecting the various blocks do not imply any particular order or dependency of the operations or portions thereof. Blocks represented by dashed lines, if any, indicate alternative operations and/or portions thereof. Dashed lines, if any, connecting the various blocks represent alternative dependencies of the operations or portions thereof. It will be understood that not all dependencies among the various disclosed operations are necessarily represented. <FIG> and the accompanying disclosure describing the operations of the method(s) set forth herein should not be interpreted as necessarily determining a sequence in which the operations are to be performed. Rather, although one illustrative order is indicated, it is to be understood that the sequence of the operations may be modified when appropriate. Accordingly, certain operations may be performed in a different order or simultaneously or substantially simultaneously. Additionally, those skilled in the art will appreciate that not all operations described need be performed.

In the foregoing description, numerous specific details are set forth to provide a thorough understanding of the disclosed concepts, which may be practiced without some or all of these particulars. In other instances, details of known devices and/or processes have been omitted to avoid unnecessarily obscuring the disclosure. While some concepts will be described in conjunction with specific examples, it will be understood that these examples are not intended to be limiting.

Reference herein to "one example" or "some examples" means that one or more feature, structure, or characteristic described in connection with the example(s) is included in at least one implementation. The phrase "one example" or "some examples" in various places in the specification may or may not be referring to the same example(s).

Different examples of the apparatus(es) and method(s) disclosed herein include a variety of components, features, and functionalities.

Claim 1:
A folding wing hinge (<NUM>) for a wing (<NUM>) having a fixed wing portion (<NUM>) and a folding wing portion (<NUM>), the folding wing hinge (<NUM>) comprising:
a hinge pin (<NUM>) including a hinge pin spline (<NUM>) and having a first longitudinal axis (<NUM>);
an input fitting (<NUM>) coupled to one of the fixed wing portion (<NUM>) and the folding wing portion (<NUM>), the input fitting (<NUM>) including an input fitting spline (<NUM>, 705A) and a second longitudinal axis (<NUM>); and
a spline coupling member (<NUM>) configured to couple with the hinge pin spline (<NUM>) and the input fitting spline (<NUM>, 705A) so that the first longitudinal axis (<NUM>) is moveable relative to the second longitudinal axis (<NUM>) by a first predetermined amount of movement (<NUM>);
wherein the hinge pin spline (<NUM>) is an external spline (<NUM>) having teeth (<NUM>) with a crowned tooth surface (<NUM>) and the spline coupling member (<NUM>) includes a first mating spline portion (<NUM>) having an internal straight-sided spline (<NUM>) configured to couple with the hinge pin spline (<NUM>); and
wherein one of:
a) the input fitting spline (<NUM>) is an external spline (<NUM>) having teeth (<NUM>) with a crowned tooth surface (<NUM>) and the spline coupling member (<NUM>) includes a second mating spline portion (<NUM>) having an internal straight-sided spline (<NUM>) configured to couple with the input fitting spline (<NUM>), wherein the respective crowned tooth surfaces of each of the hinge pin spline (<NUM>) and the input fitting spline (<NUM>) form respective universal joints (<NUM>, <NUM>) with the spline coupling member (<NUM>); and
b) the input fitting spline (705A) is an internal straight-sided spline (709A) and the spline coupling member (<NUM>) includes a second mating spline portion (712A) having teeth (<NUM>) with a crowned tooth surface (<NUM>) configured to couple with the input fitting spline (<NUM>), wherein crowned tooth surfaces (<NUM>) of the hinge pin spline (<NUM>) and tooth surfaces (<NUM>) of the input fitting spline (705A) form respective universal joints (<NUM>, <NUM>) with the spline coupling member (<NUM>).