Patent Description:
Such a wing comprises a fixed wing for being mounted to a fuselage, and a foldable wing tip portion mounted to the fixed wing via a hinge or hinges rotatable about a hinge axis between an extended position, where the foldable wing tip portion extends as a continuous extension of the fixed wing preferably in a common plane with the fixed wing, and a folded position, where the foldable wing tip portion extends upwards or rearwards in order to reduce the overall span of the aircraft compared to the extended position (see e.g. document <CIT>). Specifically, when the foldable wing tip portion is foldable upwards, the hinge axis extends in a horizontal plane and/or in parallel to a chord line and/or in parallel to the wing surface and/or in a flight direction of the aircraft. Alternatively, when the foldable wing tip portion is foldable rearwards, the hinge axis extends in a vertical direction and/or in a wing depth direction and/or in a direction transverse or perpendicular to the wing surface.

The hinge comprises a tip hinge part mounted, preferably fixedly mounted, to the foldable wing tip portion and a wing hinge part mounted, preferably fixedly mounted, to the fixed wing and engaging the tip hinge part in a manner rotatable about the hinge axis. Preferably, the foldable wing tip portion is foldable upwards and the hinge axis is located at the upper leading edge side of the fixed wing. Further preferably, the tip hinge part is in the form of a goose neck, so that the foldable wing tip portion in the folded position can be pivoted to a far inboard position above the upper surface of the fixed wing.

The wing further comprises an actuation mechanism for actuating the foldable wing tip portion for movement between the extended position and the folded position. The actuation mechanism comprises a drive arm mounted to the fixed wing in a manner rotatably driven about a drive axis, preferably by a motor. For example, the drive arm might be mounted to a rotating drive shaft driven by a motor, such as an output shaft. The drive arm is configured to effect movement of the foldable wing tip portion between the extended position and the folded position upon rotation of the drive arm about the drive axis.

Foldable wings are developed in order to reduce the space requirements of an aircraft during maneuver and parking on ground. As soon as the aircraft has landed the foldable wing tip portions of the wings are folded upwards or rearwards, thereby reducing the overall span of the aircraft.

Some known foldable wings have an actuation mechanism including a drive arm that is directly or indirectly mounted with its distal end to the foldable wing tip portion, e.g. via a linkage. Other known foldable wings have an actuation mechanism including two housing parts rotating relative to one another, one housing part mounted to the fixed wing and the other housing part mounted to the foldable wing tip portion.

The object of the present invention is to provide a wing having a simple, reliable and space-efficient actuation mechanism.

This object is achieved by means of the features according to claim <NUM>, in that the actuation mechanism comprises a catch element, e.g. in the form or a stop element or a pin, mounted to, preferably fixedly mounted to, the tip hinge part or to the structure of the foldable wing tip portion. The drive arm and the catch element are configured such that in the extended position of the foldable wing tip portion upon rotation of the drive arm the drive arm contacts the catch element, i.e. comes into contact with, butts against or strikes against the catch element, and upon further rotation pushes the foldable wing tip portion towards the folded position.

In such a way, a wing with a very simple, compact and reliable actuation mechanism is provided that allows easy assembly and maintenance.

According to a preferred embodiment, the drive axis is coaxial with the hinge axis. In such a way, the contact between the drive arm and the catch element is locally fixed, i.e. on locally fixedly locations of the drive arm and the catch element and not in the form of e.g. a sliding contact. This allows the catch element to be formed as a discrete contact or point contact, such as a pin, instead of being formed e.g. as an elongate guide surface.

According to an alternative preferred embodiment, the drive axis is parallelly spaced from the hinge axis. Preferably the catch element is formed as an elongate guide surface along which the drive arms slides or alternatively rolls by a roller mounted to the drive arm, while the drive arm pushes the foldable wing tip portion towards the folded position. In such a way, the torque applied to the foldable wing tip portion and its rotational speed during rotation from the extended position to the folded position can be tailored as required.

According to another preferred embodiment, the actuation mechanism comprises a latch mechanism for latching the foldable wing tip portion against the fixed wing in the extended position. Preferably, the latch mechanism can be operated by rotation of the drive arm. In such a way, movement of the foldable wing tip portion between the extended position and the folded position as well as latching of the foldable wing tip portion in the extended position can be actuated only by movement of the drive arm, and thus only by a single motor, which largely simplifies the wing.

In particular, it is preferred that the latch mechanism comprises a wing latch part mounted to, preferably fixedly mounted to, the fixed wing, and a tip latch part mounted to the foldable wing tip portion in a manner rotatable about a latch axis. The latch axis preferably is parallelly spaced from the drive axis. Preferably, the tip latch part can be brought into latching engagement with the wing latch part by rotating the tip latch part about the latch axis when the foldable wing tip portion is in the extended position. Preferably, the drive arm is coupled to the tip latch part via a latch link, such that the drive arm when rotating about the drive axis causes the tip latch part, through the latch link, to rotate about the latch axis. Preferably, the latch link is rotatably mounted to the drive arm by a rotatable joint, preferably at its one end, and is rotatably mounted to the tip latch part by a rotatable joint, preferably at its opposite end. In such a way, a simple, efficient and reliable latch mechanism is provided.

It is further preferred that the wing latch part is formed as a bolt or shaft. Preferably, the tip latch part is formed as a semi-circular sleeve engaging the bolt or shaft. As an alternative to the semi-circular sleeve the tip latch part might also be formed as a hook engaging the bolt or shaft.

According to a preferred embodiment, the actuation mechanism is configured such that the drive arm rotates about the drive axis from a first position along a first angular range to a second position and subsequently from the second position along a second angular range to a third position, preferably by continuous rotation. In the first position of the drive arm the tip latch part is in a latched position relative to the wing latch part. In the second position of the drive arm the tip latch part is in an unlatched position relative to the wing latch part. When the drive arm is rotated along the first angular range from the first position to the second position, the tip latch part is rotated about the latch axis from the latched position to the unlatched position. Preferably, in the first position and along the first angular range the drive arm is out of contact with the catch element. Preferably, in or near the second position the drive arm contacts, preferably strikes against, the catch element. Preferably, when the drive arm is rotated along the second angular range from the second position to the third position, the drive arm is in contact, preferably continuous contact, with the catch element, while the foldable wing tip portion is moved from the extended position to the folded position. In such a way, by continuous rotation of the drive arm the foldable wing tip portion can first be unlatched from the fixed wing and then be moved to the folded position.

According to a further preferred embodiment, the actuation mechanism comprises a pull-back mechanism for pulling the foldable wing tip portion from the folded position back to the extended position. Preferably, the pull-back mechanism comprises a pull-back catch, such as a pin or a projection, mounted to, preferably fixedly mounted to, the tip hinge part or to the structure of the foldable wing tip portion. Preferably, the pull-back mechanism further comprises a pull-back element, preferably in the form of a hook, mounted to, preferably fixedly mounted to, the tip latch part, to the latch link, or to the drive arm, and configured for engaging the pull-back catch to pull back the foldable wing tip portion from the folded position to the extended position when the drive arm is rotated in a reverse direction, i.e. reverse from the direction in which the drive arm rotates to move the foldable wing tip portion to the folded position. Preferably, the pull-back mechanism is configured such that the pull-back element is engaged with the pull-back catch when the tip latch part is in the unlatched position, and the pull-back element is disengaged from the pull-back catch when the tip latch part is in the latched position. In such a way, a simple and efficient pull back mechanism is provided that can be operated also by rotation of the drive arm. The pull-back mechanism enables the actuation mechanism to bring the foldable wing tip portion back to the extended position in cases where the gravitational force is not sufficient to do so.

According to a further preferred embodiment, when the drive arm is in the first position, the drive arm and the latch link are in an over-centred state, where the rotatable joint between the drive arm and the latch link is not aligned with the drive axis and the rotatable joint between the latch link and the tip latch part, i.e. the rotatable joint between the drive arm and the latch link does not lie on a straight line connecting the drive axis and the rotatable joint between the latch link and the tip latch part, but is offset from said line to a certain extent in an inboard direction, i.e. in the direction to the fuselage. Preferably, in the first position of the drive arm the drive arm and/or the latch link rests against a stop member preferably fixedly mounted to the fixed wing and limiting rotation of the drive arm beyond the first position, i.e. before the first position, preferably in the inboard direction. By such a configuration of the drive arm and the latch link being in an over-centred state in the first position of the drive arm and at the same time resting against the stop member, a self-locking effect for the tip latch part can be achieved, so that the tip latch part cannot rotate out of the latched position on its own, as this would merely push the drive arm or latch link further onto the stop member which thus blocks any rotation of the tip latch part out of the latched position. The only way for the tip latch part to rotate out of the latched position is being pulled by the drive arm and latch link when the drive arm rotates out of the first position towards the second position, thereby eliminating the over-centred state of the drive arm and the latch link.

According to a further preferred embodiment, the actuation mechanism comprises a locking mechanism for locking the tip latch part and the wing latch part in latching engagement with one another. Preferably, the locking mechanism can be operated by rotation of the drive arm. In such a way, no separate motor is required to operate the locking mechanism. Rather, all components of the actuation mechanism can be operated by rotation of drive arm only requiring a single motor.

In particular, it is preferred that the locking mechanism comprises a locking element, such as a locking cam, mounted to the fixed wing in a manner rotatable about a locking axis between a locked position and an unlocked position. The locking axis is preferably parallelly spaced from the drive axis. In the locked position the locking element engages the tip latch part, preferably a latch cam in the form of a corresponding surface, recess or projection of the tip latch part, and thereby inhibits the tip latch part from rotating out of the latched position. In the unlocked position the locking element is disengaged from the tip latch part and allows rotation of the tip latch part towards the unlatched position. In such a way, a simple and efficient locking mechanism for locking the tip latch part in the latched position is provided.

It is further preferred that the locking element is moved between the locked position and the unlocked position by a locking linkage that can be operated by rotation of the drive arm about the drive axis. Such a locking linkage is a simple and reliable way to operatively couple the locking element to the drive arm.

It is particularly preferred that the locking linkage comprises a locking drive arm, a swinging link, a first locking link, and a second locking link. The locking drive arm is mounted to the fixed wing in a manner rotatable about the drive axis and rotationally fixed with the drive arm, with respect to the drive axis. Preferably, the locking drive arm extends under an angle of between <NUM>° and <NUM>°, preferably <NUM>°, from the drive arm. The swinging link is mounted to the fixed wing in a manner rotatable about a swinging axis and having first and second link portions on opposite sides of the swinging axis, preferably extending away from the swinging axis in opposite direction or at least partly opposite directions. The first locking link couples the first link portion of the swinging link to the locking drive arm, preferably by being rotatably mounted to the locking drive arm at a first end and rotatably mounted to the first link portion at an opposite second end of the first locking link. The second locking link couples the second link portion of the swinging link to the locking element, preferably by being rotatably mounted to the locking element at a first end and rotatably mounted to the second link portion at an opposite second end of the second locking link. In such a way, a simple and efficient locking linkage is provided.

It is also preferred that the locking element and the tip latch part are configured to engage in a snapping manner, when the locking element is rotated into the locked position and the tip latch part is in the latched position. This can be realized for example by the corresponding portions of the locking element and the tip latch part contacting each other and slightly deform before snapping into the locked position, e.g. caused by slightly eccentric contours of the latch cam and the locking cam. By such a snapping engagement of the locking element and the tip latch part a self-closing effect can be achieved that makes the locking process more simple and more secure.

A further aspect of the present invention relates to an actuation mechanism for the wing, not being part of the claimed subject-matter, according to any of the afore-described embodiments. The features and effects described above in connection with the wing apply vis-à-vis to the actuation mechanism. In particular, the actuation mechanism comprises a drive arm configured for being mounted to the fixed wing in a manner rotatably driven about a drive axis. The drive arm is configured to effect movement of the foldable wing tip portion between the extended position and the folded position upon rotation of the drive arm about the drive axis. The drive arm is configured such that in the extended position of the foldable wing tip portion upon rotation of the drive arm the drive arm contacts the catch element and upon further rotation pushes the foldable wing tip portion towards the folded position.

Yet a further aspect of the present invention relates to an aircraft comprising a wing according to any of the embodiment described above or to an actuation mechanism according to any of the embodiment described above. The features and effects described above in connection with the wing and the actuation mechanism apply vis-à-vis to the aircraft.

Hereinafter, embodiments of the invention are described in more detail by mean of a drawing. The drawing shows in.

<FIG> show an exemplary aircraft <NUM> according to an embodiment of the present invention. The aircraft <NUM> comprises a foldable wing <NUM> including a fixed wing <NUM> mounted to a fuselage <NUM>, and a foldable wing tip portion <NUM> movably mounted to the fixed wing <NUM>.

<FIG> illustrate a first embodiment of the wing <NUM> of the aircraft <NUM> shown in <FIG> in further detail. The foldable wing tip portion <NUM> is mounted to the fixed wing <NUM> via a hinge <NUM> rotatable about a hinge axis <NUM> between an extended position <NUM> and a folded position <NUM>. In the extended position <NUM> the foldable wing tip portion <NUM> extends as a continuous extension of the fixed wing <NUM> in a common plane with the fixed wing <NUM>, wherein in the folded position <NUM> the foldable wing tip portion <NUM> extends upwards in order to reduce the overall span of the aircraft <NUM>. The hinge axis <NUM> extends in parallel to a chord line and in a flight direction of the aircraft <NUM>. The hinge <NUM> comprises a tip hinge part <NUM> mounted to the foldable wing tip portion <NUM> and a wing hinge part <NUM> mounted to the fixed wing <NUM> and engaging the tip hinge part <NUM> in a manner rotatable about the hinge axis <NUM>. The hinge axis <NUM> is located at the upper leading edge side of the fixed wing 5and the tip hinge part <NUM> is in the form of a goose neck, so that the foldable wing tip portion <NUM> in the folded position <NUM> can be pivoted to a far inboard position above the upper surface of the fixed wing <NUM>.

The wing <NUM> further comprises an actuation mechanism <NUM> for actuating the foldable wing tip portion <NUM> for movement between the extended position <NUM> and the folded position <NUM>. The actuation mechanism <NUM> comprises a drive arm <NUM> mounted to the fixed wing <NUM> in a manner rotatably driven about a drive axis <NUM> by a motor (not shown). Specifically, the drive arm <NUM> is mounted to a rotating drive shaft <NUM> driven by the motor. The drive arm <NUM> is configured to effect movement of the foldable wing tip portion <NUM> between the extended position <NUM> and the folded position <NUM> upon rotation of the drive arm <NUM> about the drive axis <NUM>.

The actuation mechanism <NUM> comprises a catch element <NUM> in the form of a pin or projection mounted to the tip hinge part <NUM>. The drive arm <NUM> and the catch element <NUM> are configured such that in the extended position <NUM> of the foldable wing tip portion <NUM> upon rotation of the drive arm <NUM> the drive arm <NUM> contacts the catch element <NUM> and upon further rotation pushes the foldable wing tip portion <NUM> towards the folded position <NUM>. In the first embodiment shown in <FIG>, the drive axis <NUM> is coaxial with the hinge axis <NUM>.

As also shown in <FIG>, the actuation mechanism <NUM> comprises a latch mechanism <NUM> for latching the foldable wing tip portion <NUM> against the fixed wing <NUM> in the extended position <NUM>. The latch mechanism <NUM> can be operated by rotation of the drive arm <NUM>. In such a way, movement of the foldable wing tip portion <NUM> between the extended position <NUM> and the folded position <NUM> as well as latching of the foldable wing tip portion <NUM> in the extended position <NUM> can be actuated only by movement of the drive arm <NUM>, and thus only by a single motor.

The latch mechanism <NUM> comprises a wing latch part <NUM> mounted to the fixed wing <NUM>, and a tip latch part <NUM> mounted to the foldable wing tip portion <NUM> in a manner rotatable about a latch axis <NUM>. The latch axis <NUM> is parallelly spaced from the drive axis <NUM>. The tip latch part <NUM> can be brought into latching engagement with the wing latch part <NUM> by rotating the tip latch part <NUM> about the latch axis <NUM> when the foldable wing tip portion <NUM> is in the extended position <NUM>. The drive arm <NUM> is coupled to the tip latch part <NUM> via a latch link <NUM>, such that the drive arm <NUM>, when rotating about the drive axis <NUM>, causes the tip latch part <NUM>, through the latch link <NUM>, to rotate about the latch axis <NUM>. The latch link <NUM> is rotatably mounted to the drive arm <NUM> by a rotatable joint at its one end and is rotatably mounted to the tip latch part <NUM> by a rotatable joint at its opposite end. The wing latch part <NUM> is formed as a bolt and the tip latch part <NUM> is formed as a semi-circular sleeve engaging the bolt.

The actuation mechanism <NUM> is configured such that the drive arm <NUM> rotates about the drive axis <NUM> from a first position <NUM> along a first angular range <NUM> to a second position <NUM> and subsequently from the second position <NUM> along a second angular range <NUM> to a third position <NUM>, in the present embodiment by continuous rotation. In the first position <NUM> of the drive arm <NUM> the tip latch part <NUM> is in a latched position <NUM> relative to the wing latch part <NUM>. In the second position <NUM> of the drive arm <NUM> the tip latch part <NUM> is in an unlatched position <NUM> relative to the wing latch part <NUM>. When the drive arm <NUM> is rotated along the first angular range <NUM> from the first position <NUM> to the second position <NUM>, the tip latch part <NUM> is rotated about the latch axis <NUM> from the latched position <NUM> to the unlatched position <NUM>. Further, in the first position <NUM> and along the first angular range <NUM> the drive arm <NUM> is out of contact with the catch element <NUM>. In the second position <NUM> the drive arm <NUM> contacts the catch element <NUM>. When the drive arm <NUM> is rotated along the second angular range <NUM> from the second position <NUM> to the third position <NUM>, the drive arm <NUM> is in continuous contact with the catch element <NUM>, while the foldable wing tip portion <NUM> is moved from the extended position <NUM> to the folded position <NUM>.

As also shown in <FIG>, the actuation mechanism <NUM> comprises a pull-back mechanism <NUM> for pulling the foldable wing tip portion <NUM> from the folded position <NUM> back to the extended position <NUM>. The pull-back mechanism <NUM> comprises a pull-back catch <NUM> in the form of a pin or a projection mounted to the tip hinge part <NUM>. The pull-back mechanism <NUM> further comprises a pull-back element <NUM> in the form of a hook mounted to the tip latch part <NUM> and configured for engaging the pull-back catch <NUM> to pull back the foldable wing tip portion <NUM> from the folded position <NUM> to the extended position <NUM> when the drive arm <NUM> is rotated in a reverse direction, i.e. reverse from the direction in which the drive arm <NUM> rotates to move the foldable wing tip portion <NUM> to the folded position <NUM>. The pull-back mechanism <NUM> is configured such that the pull-back element <NUM> is engaged with the pull-back catch <NUM> when the tip latch part <NUM> is in the unlatched position <NUM>, and the pull-back element <NUM> is disengaged from the pull-back catch <NUM> when the tip latch part <NUM> is in the latched position <NUM>. The pull-back mechanism <NUM> enables the actuation mechanism <NUM> to bring the foldable wing tip portion <NUM> back to the extended position <NUM> in cases where the gravitational force is not sufficient to do so.

As visible in <FIG>, when the drive arm <NUM> is in the first position <NUM>, the drive arm <NUM> and the latch link <NUM> are in an over-centred state, where the rotatable joint between the drive arm <NUM> and the latch link <NUM> is not aligned with the drive axis <NUM> and the rotatable joint between the latch link <NUM> and the tip latch part <NUM>, i.e. the rotatable joint between the drive arm <NUM> and the latch link <NUM> does not lie on a straight line connecting the drive axis <NUM> and the rotatable joint between the latch link <NUM> and the tip latch part <NUM>, but is offset from said line to a certain extent in an inboard direction, i.e. in the direction to the fuselage <NUM>. In the first position <NUM> of the drive arm <NUM> the drive arm <NUM> rests against a stop member <NUM> mounted to the fixed wing <NUM> and limiting rotation of the drive arm <NUM> beyond the first position <NUM>, i.e. before the first position <NUM>, in the inboard direction. By such a configuration of the drive arm <NUM> and the latch link <NUM> being in an over-centred state in the first position <NUM> of the drive arm <NUM> and at the same time resting against the stop member <NUM>, a self-locking effect for the tip latch part <NUM> can be achieved, so that the tip latch part <NUM> cannot rotate out of the latched position <NUM> on its own, as this would merely push the drive arm <NUM> further onto the stop member <NUM> which thus blocks any rotation of the tip latch part <NUM> out of the latched position <NUM>. The only way for the tip latch part <NUM> to rotate out of the latched position <NUM> is being pulled by the drive arm <NUM> and latch link <NUM> when the drive arm <NUM> rotates out of the first position <NUM> towards the second position <NUM>, thereby eliminating the over-centred state of the drive arm <NUM> and the latch link <NUM>.

In <FIG> a second embodiment of the invention is shown that differs from the first embodiment shown in <FIG> in that the actuation mechanism <NUM> further comprises a locking mechanism <NUM> for locking the tip latch part <NUM> and the wing latch part <NUM> in latching engagement with one another. The locking mechanism <NUM> can be operated by rotation of the drive arm <NUM>. The locking mechanism <NUM> comprises a locking element <NUM> in the form of a locking cam mounted to the fixed wing <NUM> in a manner rotatable about a locking axis <NUM> between a locked position <NUM> and an unlocked position <NUM>. The locking axis <NUM> is parallelly spaced from the drive axis <NUM>. In the locked position <NUM> the locking element <NUM> engages the tip latch part <NUM>, specifically a latch cam of the tip latch part <NUM>, and thereby inhibits the tip latch part <NUM> from rotating out of the latched position <NUM>. In the unlocked position <NUM> the locking element <NUM> is disengaged from the tip latch part <NUM> and allows rotation of the tip latch part <NUM> towards the unlatched position <NUM>.

As shown in <FIG>, the locking element <NUM> is moved between the locked position <NUM> and the unlocked position <NUM> by a locking linkage <NUM> that can be operated by rotation of the drive arm <NUM> about the drive axis <NUM>. The locking linkage <NUM> comprises a locking drive arm <NUM>, a swinging link <NUM>, a first locking link <NUM>, and a second locking link <NUM>. The locking drive arm <NUM> is mounted to the fixed wing <NUM> in a manner rotatable about the drive axis <NUM> and rotationally fixed with the drive arm <NUM>, with respect to the drive axis <NUM>. In the present embodiment, the locking drive arm <NUM> extends under an angle of about <NUM>° from the drive arm <NUM>. The swinging link <NUM> is mounted to the fixed wing <NUM> in a manner rotatable about a swinging axis <NUM> and having first and second link portions <NUM>, <NUM> on opposite sides of the swinging axis <NUM> and extending away from the swinging axis <NUM> in opposite directions or at least partly opposite directions. The first locking link <NUM> couples the first link portion <NUM> of the swinging link <NUM> to the locking drive arm <NUM> by being rotatably mounted to the locking drive arm <NUM> at a first end and rotatably mounted to the first link portion <NUM> at an opposite second end of the first locking link <NUM>. The second locking link <NUM> couples the second link portion <NUM> of the swinging link <NUM> to the locking element <NUM> by being rotatably mounted to the locking element <NUM> at a first end and rotatably mounted to the second link portion <NUM> at an opposite second end of the second locking link <NUM>.

The locking element <NUM> and the tip latch part <NUM> are configured to engage in a snapping manner, when the locking element <NUM> is rotated into the locked position <NUM> and the tip latch part <NUM> is in the latched position <NUM> or rotated to the latched position <NUM>. In the present embodiment, this is realized by the corresponding portions of the locking element <NUM> and the tip latch part <NUM>, i.e. the locking cam and the latch cam, contacting each other and slightly deform before snapping into the locked position <NUM>. This is caused by slightly eccentric contours of the latch cam and the locking cam. By such a snapping engagement of the locking element <NUM> and the tip latch part <NUM> a self-closing effect of the locking mechanism <NUM> is achieved.

In <FIG> a third embodiment of the invention is shown that differs from the first embodiment shown in <FIG> in that the drive axis <NUM> is parallelly spaced from the hinge axis <NUM>, instead of being coaxial with the hinge axis <NUM>. Further, the catch element <NUM> is formed as an elongate guide surface along which the drive arm <NUM> rolls by a roller <NUM> mounted to a projecting part of the drive arm <NUM>, while the drive arm <NUM> pushes the foldable wing tip portion <NUM> towards the folded position <NUM>. By such an arrangement, the torque applied to the foldable wing tip portion <NUM> and its rotational speed during rotation from the extended position <NUM> to the folded position <NUM> can be tailored as required.

Claim 1:
A wing (<NUM>) for an aircraft (<NUM>), comprising
a fixed wing (<NUM>),
a foldable wing tip portion (<NUM>) mounted to the fixed wing (<NUM>) via a hinge (<NUM>) rotatable about a hinge axis (<NUM>) between an extended position (<NUM>) and a folded position (<NUM>), and
an actuation mechanism (<NUM>) for actuating the foldable wing tip portion (<NUM>) for movement between the extended position (<NUM>) and the folded position (<NUM>),
wherein the hinge (<NUM>) comprises a tip hinge part (<NUM>) mounted to the foldable wing tip portion (<NUM>) and a wing hinge part (<NUM>) mounted to the fixed wing (<NUM>) and engaging the tip hinge part (<NUM>) in a manner rotatable about the hinge axis (<NUM>),
wherein the actuation mechanism (<NUM>) comprises a drive arm (<NUM>) mounted to the fixed wing (<NUM>) in a manner rotatably driven about a drive axis (<NUM>), and
wherein the drive arm (<NUM>) is configured to effect movement of the foldable wing tip portion (<NUM>) between the extended position (<NUM>) and the folded position (<NUM>) upon rotation of the drive arm (<NUM>) about the drive axis (<NUM>),
characterized in that
the actuation mechanism (<NUM>) comprises a catch element (<NUM>) mounted to the tip hinge part (<NUM>) or to the structure of the foldable wing tip portion (<NUM>), and
the drive arm (<NUM>) and the catch element (<NUM>) are configured such that in the extended position (<NUM>) of the foldable wing tip portion (<NUM>) upon rotation of the drive arm (<NUM>) the drive arm (<NUM>) contacts the catch element (<NUM>) and upon further rotation pushes the foldable wing tip portion (<NUM>) towards the folded position (<NUM>).