Patent Description:
For increasing the lift coefficient of a wing of a commercial aircraft, high lift systems are known. These may include trailing edge flaps, and leading-edge devices. During takeoff and landing, they are usually activated, i.e. moved from a retracted into an extended position.

Leading-edge slats usually comprise a front skin, a back skin and mechanical interfaces for coupling with a slat track.

<CIT> describes an aircraft wing slat that is formed from composite materials using lay-up and vacuum bagging techniques. The slat lay-up comprises a central honeycomb core sandwiched between upper and lower composite skins, a pre-cured spar and pre-cured stiffeners. After the lay-up is cured and removed from a lay-up mold, leading edge strengthening ribs and a preformed composite nose skin are installed to complete the slat.

<CIT> describes a slat assembly adapted to be mounted to a main wing of an aircraft and comprising a slat having a leading edge, two elongate slat tracks, each extending along a respective plane. The two planes are parallel to and spaced from each other and, of all possible planes along which the two slat tracks extend, are the planes having the maximum perpendicular distance from each other. The slat tracks are connected to the slat at two locations spaced from each other in a direction perpendicular to the planes, wherein the two slat tracks are adapted to be mounted to a main wing of an aircraft such that they are selectively movable along the associated plane between a retracted position and an extended position to thereby move the slat between a stowed position and a deployed position, and a drive arrangement drivingly engaging the two slat tracks and operable to effect synchronous and parallel movement of the slat tracks between the retracted position and the extended position. The connection between the slat and one or both of the slat tracks is realized by a respective interconnection portion, which extends between at least part of the slat and at least part of the respective slat track and comprises a first portion secured to or integrally formed with the slat and a second portion secured to or integrally formed with the respective slat track. The first and second portions are spaced from each other along the plane of the respective slat track. The interconnection portion is elastically deformable and constructed in such a manner that a first stiffness against deformation about a first axis, which extends perpendicular to the planes, is at least ten times a second stiffness against deformation about a second axis, which extends perpendicularly to the first axis and between the first and second portions of the interconnection portion, and at least ten times a third stiffness against deformation about a third axis, which extends perpendicularly to the first and second axes.

It is an object of the invention to propose an alternative wing leading-edge device that comprises a further increased mechanical reliability.

This object is met by the wing leading-edge device having the features of independent claim <NUM>. Advantageous embodiments and further improvements may be gathered from the subclaims and the following description.

According to a first aspect of the invention, a wing leading-edge device is proposed, comprising a flow body having a front side, a back side and a plurality of ribs arranged in the flow body, wherein at least one of the ribs is a load introduction rib comprising at least one first lug for coupling with a drive mechanism, further comprising a second load path component, which comprises at least one second lug, wherein the second load path component is attached through several connection means to the load introduction rib and rests flushly and directly on the load introduction rib, such that a second opening of the at least one second lug is co-axial with a corresponding first opening of the at least one first lug.

The flow body may comprise an elongate shape that extends along a spanwise direction of the wing to which it is attached. The flow body further comprises a certain profile contour, which is mainly determined by the desired aerodynamic characteristics. It is preferred that the flow body is sufficiently stiff to serve for the intended purpose. It may be preferred that the flow body comprises stiffening elements, such as ribs, spars and also stringers, which are arranged on an inner side of e.g. a front skin.

In the context of the invention, several ribs are arranged inside the flow body, which all act as stiffening elements. At least one of them and preferably two of the ribs act as load introduction ribs. They are mechanically adapted for a reliable load transfer between the flow body and a drive mechanism, such as a slat track mechanism or similar. Consequently, the at least one lug in the at least one load introduction rib is provided for coupling with a drive mechanism. By coupling the at least one lug with the drive mechanism, a first load path between the drive mechanism and the flow body is provided.

By arranging the second load path component into the flow body and connecting it at least to the load introduction rib, a second load path between the drive mechanism and the flow body is created. If the load introduction rib experiences a mechanical impairment, the second load path component may thus transfer the mechanical load from the at least one second lug to the remaining part of the flow body.

The lugs each comprise at least one opening. The first lug comprises at least one first opening and the second lug comprises at least one second opening. When arranging a first lug relative to a second lug such that their openings are co-axial, a bolt, an axle or any other suitable component may extend through both lugs. This also includes differently shaped openings in both lugs. For example, an opening of one of the lugs may be somewhat larger than the opening of the other lug. In this way, e.g. the smaller opening defines a primary load path, while the larger opening leads to a secondary load path. Hence, co-axial openings do not rule out tolerances in the dimensions and shapes of the respective openings.

For the sake of completeness, the term co-axial may also be referred to as coaxal or concentric. Two openings are concentric, coaxal, or coaxial when they share the same center point or axis.

The second load path component may comprise an arbitrary shape, which mainly depends on the remaining parts inside the flow body. It may comprise a chamfered section, a flange, one or several lugs or attachment points. Its shape is adapted to the part of the flow body, to which it is attached. For example, it may be attached to the load introduction rib completely, to a spar, to a skin or a combination thereof. In the following, some embodiments are provided, in which more precise shapes are defined.

Advantageously, the flow body comprises a spar that substantially extends parallel to a spanwise leading edge of the flow body and that separates the flow body into a front section and at least one rear section, wherein the at least one lug is arranged in the at least one rear section. A plurality of spars may be used that are arranged in the flow body. The load introduction rib thus extends from a rear section to the front section. The at least one lug is arranged in the rear section and thus faces a fixed leading edge, to which the leading-edge device may be coupled.

In an advantageous embodiment, the spar is arranged transverse to the ribs, wherein the second load path component is chamfered and connected to both the load introduction rib and the spar. The second load path component may thus be connected to the rib in the region of the at least one first lug. Since the rib is arranged transverse to the spar, a chamfered design of the second load path component allows the second load path to also extend along at least a part of the spar directly forward the at least one first lug. By connecting the second load path component to the spar, an additional load path extends from the at least one second lug to the spar. Preferably, the second load path component comprises an upper flange connected to the spar. The upper flange may be a chamfered part of the second load path component and extends upwardly.

Preferably, the second load path component extends along at least <NUM>% of an internal height of the spar inside the flow body. In this case, the second load path component may comprise a stripe-shaped section that is attached to a section that is connected with the load introduction rib. However, two stripe-shaped sections may be provided, which are attached to both sides of the section that is connected to the rib. In this case, the second load path component may comprise a symmetrical design. By extending over this substantial height of the spar, many individual connections between second load path component and the spar can be provided. In this regard, the internal height of the spar is to be understood as a clear extension between two opposed ends of the spar in a vertical direction. The vertical direction may be a z-axis of the aircraft, to which the flow body is coupled. It may also be an axis transverse to both the spanwise axis and the chordwise axis of the flow body.

In an advantageous embodiment, the second load path component may be a flat component and exclusively connected to the respective load introduction rib. Thus, it is flushly attached to the load introduction rib or a pocketed area of the load introduction rib through several connecting means. It may extend over a substantial part of the load introduction rib and thus provides a rather large second load path. The second load path component may thereby have a shape that partially corresponds to the shape of the respective load introduction rib. However, its extension may be clearly smaller. For example, it may roughly comprise an L-shape having a first surface section and a second surface section that are arranged transverse to each other, wherein the first surface section comprises the at least one second lug and substantially extends along a chordwise axis, while the second surface section extends along a substantially vertical axis to extend along the forward section of the load introduction rib. However, other shapes are possible. For example, the second load path component may comprise the shape of the load introduction rib in a forward section, while a flange or a web is arranged in the rearward section to merely cover a part of the load introduction rib that comprises the at least one first lug.

Advantageously, the second load path component extends from the at least one rear section into the front section. The load transfer is thus achieved over a large surface area and may be provided substantially over the whole load introduction rib.

In a further advantageous embodiment, the second load path component comprises an upper flange and/or a lower flange connected to at least one of a front skin and a back skin of the flow body forward or above of the at least one second lug. These flanges may thus provide a connection of the second load path component to at least one of the two skins that are arranged on the flow body. It is feasible to provide both flanges to connect the second load path component to both skins. However, it may also be possible to attach the second load path component to just one of the skins. This may particularly be the case if the at least one first lug is arranged on a part of the respective load introduction rib that sticks out of a hollow space of the flow body, for instance through a suitable cut-out. The upper flange may then extend into the direction of an upper delimiting edge of the cut-out. Here, a connection to the spar may be created with the upper flange.

Still further, the second load path component may comprise at least one lateral flange connected to the spar. The lateral flange may be a chamfered part of the second load path component and provides a reliable load transfer.

In another advantageous embodiment, the load introduction rib and the second load path component are mirror inverted and each comprise a flat attachment surface, wherein the load introduction rib and the second load path component are attached to one another through the attachment surfaces. Thus, an assembly is created that has the shape of a common load introduction rib, which is divided in a chordwise direction into two halves, wherein one of the halves constitutes the load introduction rib and the other half constitutes the second load path component. Hence, both halves together create the first and the second load path. Both the load introduction rib and the second load path component comprise matching attachment surfaces that are substantially identically dimensioned. The assembly may comprise an increased width compared to common ribs. Consequently, by doubling substantially the complete load introduction rib, the reliability of the load transfer from the at least one first lug to the drive mechanism is clearly increased.

It may be feasible to provide an additional flat component between the attachment surfaces as a crack stopper. The flat component may be realized in the form of a plate or inlay. It may comprise a stiff material like steel or titanium.

Instead or additional to the use of a spar or other stiffening components, the flow body may also comprise at least one stringer that extends substantially parallel to a spanwise leading edge of the flow body at least along a front skin of the flow body, wherein the second load path component is coupled with the at least one stringer. This may be considered for flow bodies that are designed according to another design principle that uses stringers, i.e. longitudinal stiffening bodies that extend in a spanwise direction.

According to a second aspect of the invention, a wing having a fixed wing body and a wing leading-edge device according to the above description is provided.

According to a third aspect of the invention, an aircraft is provided, having at least one such wing.

Other characteristics, advantages and potential applications of the present invention result from the following description of the exemplary embodiments illustrated in the figures. In this respect, all described and/or graphically illustrated characteristics also form the object of the invention individually and in arbitrary combination regardless of their composition in the individual claims or their references to other claims. Furthermore, identical or similar objects are identified by the same reference symbols in the figures.

<FIG> shows a first exemplary embodiment of a wing leading-edge device <NUM> in a lateral, cross-sectional view. The wing leading-edge device <NUM> comprises a flow body <NUM> having a front side <NUM>, a back side <NUM> and a plurality of ribs <NUM> arranged in the flow body <NUM>. The ribs <NUM> are distributed in the flow body <NUM> along a spanwise axis, such that the flow body <NUM> is stiffened. For coupling the flow body <NUM> with a drive mechanism (not shown), one or two of the ribs <NUM> constitute a load introduction rib.

The rib <NUM> comprises a first lug <NUM> in the form of a web, in which a first opening <NUM> is arranged. In this regard, the first opening <NUM> is to be understood as an opening in the first lug <NUM>. The first lug <NUM> exemplarily comprises two first openings <NUM>. One of these is arranged in a forward position and one is arranged in a rearward position. Here, only one first opening <NUM> is visible, which is arranged at a rear end of the first lug <NUM>. A further forward first opening <NUM> is covered by a second load path component <NUM>.

The second load path component <NUM> comprises a second lug <NUM>, which has a second opening <NUM> that is positioned in a co-axial manner with a corresponding first opening <NUM> of the first lug <NUM>. In the context of the invention this is to be understood as the respective openings <NUM> and <NUM> of the lugs <NUM> and <NUM> being arranged concentrically to each other, such that a bolt or another device may extend through the openings of both lugs to provide a rotatability around the common axis of the openings of both lugs. The second load path component <NUM> is connected to the load introduction rib <NUM> in the region of the first lug <NUM> and extends over approximately half the surface of the first lug <NUM>. Forward of the first lug <NUM> and the second load path component <NUM>, a spar <NUM> is arranged. The second load path component <NUM> is chamfered and may exemplarily comprise a stripe shaped extension or upper flange <NUM> transverse to the first lug <NUM> and parallel to the spar <NUM>. The upper flange <NUM> is connected to the spar <NUM> substantially along the whole available height of the spar <NUM>. This may be at least <NUM>% of the available height.

When attaching the wing leading-edge device <NUM> to a drive mechanism, such as a slat track, a connection is made by using the first lug <NUM> as well as the second lug <NUM>, as its second opening <NUM> is co-axial with a first opening <NUM> of the first lug <NUM>. The load between the flow body <NUM> and the respective drive mechanism is transferred over a first load path in the form of the load introduction rib <NUM>. A second load path is created through the second load path component <NUM>. Thus, two individual load paths are created for increasing the reliability and safety of the wing leading-edge device <NUM>. For the sake of completeness, further depicted elements are briefly explained. They are not absolutely required in their illustrated design and may also be modified according to individual requirements. For example, a back skin <NUM> is arranged on the back side <NUM>, while a front skin <NUM> is arranged on the front side <NUM>. An upper, trailing edge <NUM> comprises a stiffening arrangement <NUM>. The wing leading-edge device <NUM> is exemplarily shown as a leading edge slat.

In <FIG>, a wing leading-edge device <NUM> is shown, which comprises a flow body <NUM> having substantially the same design as flow body <NUM> in <FIG>. However, a second load path component <NUM> is provided, which differs from the second load path component <NUM> of <FIG>. The spar <NUM> separates the flow body <NUM>, as in the above and all remaining exemplary embodiments, into a front section <NUM> and a rear section <NUM>. Further, in this exemplary embodiment, the second load path component <NUM> is a substantially flat component, which roughly comprises an L-shape that extends to a front section <NUM> of the flow body <NUM> that is forward the spar <NUM>. In this example, the second load path component <NUM> is exclusively connected to the load introduction rib <NUM>. In the shape of the second load path component <NUM> a first surface section <NUM> extends along at least a part of the first lug <NUM>. Another surface section <NUM> substantially extends over the whole available height of the rib <NUM> in the front section <NUM>. As the second load path component <NUM> extends into the front section <NUM>, the spar <NUM> may comprise a cutout at least for the first surface section <NUM>.

<FIG> shows a still further embodiment of a wing leading-edge device <NUM> having a flow body <NUM>, which is similarly designed to the previous exemplary embodiments. However, a second load path component <NUM> is provided, which is attached to the first lug <NUM> of the load introduction rib <NUM> and comprises an upper flange <NUM> and a lower flange <NUM> that both extend in a substantially chordwise direction. The upper flange <NUM> is attached to the back skin <NUM>, while the lower flange <NUM> is attached to the front skin <NUM>. Furthermore, the second load path component <NUM> may comprise a central portion <NUM>, which is connected to the spar <NUM>. Thus, the second load path component <NUM> has a plurality of connections to different parts of the flow body <NUM>, which leads to an even further increased reliability through creation of a second load path.

<FIG> shows a further exemplary embodiment in form of a wing leading-edge device <NUM> having a flow body <NUM>, which has a similar design as the flow bodies <NUM>, <NUM> and <NUM> explained above. A second load path component <NUM> is provided, which is attached to the first lug <NUM> of the load introduction rib <NUM> and comprises an extension <NUM>, which extends into the front section <NUM> of the flow body <NUM>. However, the extension <NUM> is only slightly larger than the section of the second load path component <NUM> that is attached to the first lug <NUM>. In addition, thereto, an upper flange <NUM> extends transverse to the extension <NUM> and parallel to the spar <NUM>. It runs along the spar <NUM> into the direction of the back skin <NUM> and ends just before reaching the back skin <NUM>. In this region, which has a similar design as the central portion <NUM> in <FIG>, the upper flange <NUM> is attached to the spar <NUM>.

<FIG> shows a sectional view of a flow body <NUM> with the load introduction rib <NUM> reaching through the spar <NUM> through a cutout <NUM>. The load introduction rib <NUM> comprises two flanges <NUM> and <NUM>. In this view, both first openings <NUM> are shown. On one side of the load introduction rib <NUM>, a second load path component <NUM> is provided. Exemplarily, this embodiment of the second load path component <NUM> comprises a second lug <NUM> with two second openings <NUM>, which are co-axial with the first openings <NUM> of the first lugs <NUM>, i.e. the openings of the lugs <NUM> and <NUM> are concentrically arranged. The second load path component <NUM> in this case is chamfered to create a lateral flange <NUM>, which is attached to the flange <NUM> of the load introduction rib <NUM>. If bolts (not shown) are inserted into the first openings <NUM> of the first lug <NUM> for connecting a slat track or a similar drive mechanism, they are also connected to the second lug <NUM> by reaching through the second openings <NUM>. Thus, a second load path is created.

<FIG> shows a slight modification in a flow body <NUM>. Here, a second load path component <NUM> is shown, which comprises a second lug <NUM>, which has one second opening <NUM> arranged co-axially with a forward first opening <NUM> of a first lug <NUM>. For providing a width of the combination of the load introduction rib <NUM> and the second load component <NUM> that does not exceed the width of a load introduction rib <NUM> without such a second load path component <NUM>, a lateral recess <NUM> is provided. However, as an alternative, the second load component <NUM> may exceed the width of the load introduction rib <NUM>. The lateral recess <NUM> ends directly rearward of the second load path component <NUM>, such that there is a step <NUM> at a rear end of the recess <NUM>. Thus, modifications for the bolts or other components are not required. In this case, the second load path component <NUM> comprises a forward flange <NUM> that is attached to the flange <NUM> of the load introduction rib <NUM>.

<FIG> shows a flow body <NUM>, which comprises two second load path components <NUM>, each having a flange <NUM> for connection to the flanges <NUM> and <NUM> as well as the spar <NUM>. The second load path components <NUM> comprise a second lug <NUM>, which in each case has a second opening <NUM> that is arranged co-axial with a forward first opening <NUM> of the corresponding first lug <NUM>, i.e. the openings <NUM> and <NUM> are concentrically arranged.

<FIG> shows a flow body <NUM>, which is similar to the exemplary embodiment of <FIG>, but with the load introduction rib <NUM> only comprising one of the flanges <NUM>. A second load path component <NUM> is provided, which is connected to the spar <NUM> and has a lateral flange <NUM>, that rests flushly and directly on the spar <NUM> or a pocketed area thereof.

Still further, <FIG> illustrates a flow body <NUM> having an assembly <NUM> that comprises a load introduction rib <NUM> in form of a first half of the assembly <NUM> and a second load path component <NUM> in the form of a second half. Both halves may have the shape of a load introduction rib <NUM> of some of the previous exemplary embodiments but may optionally comprise a greater width. They comprise flat attachment surfaces <NUM> and <NUM>, which can be brought into surface contact, such that a symmetrical assembly <NUM> is created. Of course, other assemblies are possible, which are not symmetrical. In this example, the attachment surfaces <NUM> and <NUM> determine a symmetry plane. The second load path component <NUM> comprises a lateral flange <NUM> for connection to the spar <NUM>. A flange <NUM> of the load introduction rib <NUM> may as well be connected to the spar <NUM>. The load introduction rib <NUM> and the second load path component <NUM> are exemplarily mirror inverted. The load introduction rib <NUM> comprises two first openings <NUM> in a first lug <NUM>. The second load path component <NUM> comprises two second openings <NUM> in a second lug <NUM>. Both first openings <NUM> are arranged co-axial with the second openings <NUM>.

Lastly, <FIG> shows an aircraft <NUM> having wings <NUM> with a wing leading-edge device <NUM>. However, all other examples may be used on the aircraft <NUM>.

Claim 1:
A wing leading-edge device (<NUM>, <NUM>, <NUM>, <NUM>), comprising:
a flow body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) having a front side (<NUM>), a back side (<NUM>) and
a plurality of ribs (<NUM>, <NUM>) arranged in the flow body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>),
wherein at least one of the ribs (<NUM>, <NUM>) is a load introduction rib (<NUM>, <NUM>) comprising at least one first lug (<NUM>) for coupling with a drive mechanism,
further comprising a second load path component (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), which comprises at least one second lug (<NUM>),
wherein the second load path component (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) is attached through several connecting means to the load introduction rib (<NUM>, <NUM>) and rests flushly and directly on the load introduction rib (<NUM>, <NUM>), such that a second opening (<NUM>) of the at least one second lug (<NUM>) is co-axial with a first opening (<NUM>) of the corresponding at least one first lug (<NUM>).