Locking device

Abstract

An aircraft wing comprises a fixed wing, and a wing tip device at the tip thereof. The wing tip device is configurable between (i) a flight configuration for use during flight, and (ii) a ground configuration for use during ground based operations. In the ground configuration with span of the wing is reduced. The wing further comprises a locking mechanism including a locking pin with a longitudinal axis, the locking pin associated with one of the fixed wing and the wing tip device, and a bush associated with the other of the fixed wing and wing tip device, the bush configured to receive the locking pin. The bush is located within a bush housing arranged to allow relative movement of the bush in the direction of the longitudinal axis of the locking pin when the locking pin is received within the bush.

Claims

1. An aircraft wing comprising: a fixed wing, and a wing tip device at the tip of the fixed wing, wherein the wing tip device is configurable between: (i) a flight configuration for use during flight, and (ii) a ground configuration for use during ground based operations, wherein in the ground configuration the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced, a locking mechanism for locking the wing tip device in the flight configuration, the locking mechanism comprising: a locking pin with a longitudinal axis, the locking pin associated with one of the fixed wing and the wing tip device, a bush associated with the other of the fixed wing and wing tip device, the bush configured to receive the locking pin when the wing tip device is in the flight configuration such that movement of the wing tip device out of the flight configuration is prevented, a bush housing within which is the bush and the bush housing arranged to allow relative movement of the bush in the direction of the longitudinal axis of the locking pin when the locking pin is received within the bush, wherein a frictional force to be overcome to allow movement of the bush relative to the bush housing in the direction of the longitudinal axis is less than a frictional force to be overcome to allow movement of the locking pin relative to the bush in the direction of the longitudinal axis.

2. The aircraft wing as in claim 1, wherein the locking pin is associated with an actuator arranged to move the locking pin into and out of engagement with the bush.

3. The aircraft wing as in claim 1, wherein the wing tip device and the fixed wing are separated along an oblique cut plane passing through the upper and lower surfaces of the wing, the oblique cut plane being orientated normal to the axis of rotation.

4. The aircraft wing as in claim 1, wherein the wing tip device and fixed wing are connected by a rotational joint, and the movement between the flight configuration and ground configuration comprises rotational movement around the rotational axis of the rotational joint.

5. The aircraft wing as in claim 4, wherein the rotational joint comprises a slew ring.

6. The aircraft wing as in claim 5, wherein the slew ring comprises an inner race fixed to one of the fixed wing and wing tip device, and an outer race fixed to the other of the fixed wing and wing tip device, and the bush is configured to stop relative rotational movement of the inner race and outer race when the locking mechanism is in the locked configuration.

7. The aircraft wing as in claim 1, wherein the bush comprises an aperture shaped to receive the locking pin.

8. The aircraft wing as in claim 1, wherein the locking pin comprises flatted edge portions.

9. The aircraft wing as in claim 1, wherein an interface between the bush and the bush housing comprise one or more flexible washers.

10. The aircraft wing as in claim 1, wherein an interface between the bush and the bush housing comprise one or more O-rings.

11. The aircraft wing as in claim 1, wherein an interface between the bush and the bush housing allows relative rotational movement between the bush and bush housing.

12. An aircraft comprising the aircraft wing in claim 1.

13. A method of locking an aircraft wing, the aircraft wing as claimed in claim 1, the method comprising the steps of: moving the wing tip device into the flight configuration, and moving the locking pin into the bush, such that movement of the wing tip device out of the flight configuration is prevented.

14. The method of claim 13, further comprising: moving the locking pin out of the bush, such that movement of the wing tip device out of the flight configuration is allowed.

Description

DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which:

(2) FIG. 1 shows a schematic view of an aircraft wing according to a first embodiment of the invention;

(3) FIG. 2 shows an aircraft comprising the aircraft wing as shown in FIG. 1;

(4) FIG. 3 shows a cross sectional side view of a locking mechanism according to an embodiment of the invention;

(5) FIG. 4 shows a top plan view of the locking mechanism shown in FIG. 3;

(6) FIG. 5 shows a bottom plan view of the locking mechanism shown in FIG. 3;

(7) FIG. 6 shows a schematic view of a wing and locking device according to an embodiment of the invention;

(8) FIG. 7 shows a section of the wing and locking device as shown in FIG. 6;

(9) FIG. 8 shows a highly schematic view of the wing and locking device shown in FIGS. 6 and 7, with various elements removed for clarity;

(10) FIG. 9 shows an alternative arrangement of the locking mechanism relative to an aircraft wing.

DETAILED DESCRIPTION

(11) FIG. 1 shows an aircraft wing 10 comprising a fixed wing 12 and a wing tip device 14 at the tip thereof. The wing tip device 14 is configurable between a flight configuration (shown in dashed lines), suitable for flight, and a ground configuration (shown in solid lines), suitable for ground based operations, e.g. with the wing span within gate limits. When in the ground configuration, the span of the aircraft wing is reduced compared to the flight configuration.

(12) FIG. 2 shows an aircraft 100, comprising a wing 10, as described above.

(13) FIG. 3 shows a cross section of a locking mechanism 30. The locking mechanism 30 comprises a first part 32 forming part of the fixed wing 12 and a second part forming a part of the wing tip device 14. The first part comprises a male locking pin 36 with a longitudinal axis Y. The male locking pin 36 is roughly cylindrical, though with two opposed flat planar portions 38 and 40, as best shown in FIG. 4. The male locking pin 36 is moved forwards and backwards in the direction of the longitudinal axis Y by an actuator (not shown). The locking pin 36 is located within a socket 13 in the fixed wing 12. The surfaces of the locking pin 36 and the socket 13 are relatively high friction surfaces, such that relative movement of the locking pin 36 and the socket 13 requires a reasonably large frictional force to be overcome when the system is loaded in shear, in particular in comparison to the frictional contact between some other elements of the locking mechanism, as will be described below. The second part 34 comprises a bush 42 which is mounted to a bush housing 44 by a pair of Belleville washers 46 and 48. The Belleville washers 46 and 48 allow a limited amount of movement of the bush 42 relative to the bush housing 44, in a direction parallel to the longitudinal axis Y. The Belleville washers 46, 48, also act to centre the bush 42 in the bush housing 44. There is a low friction interface between the bush 42 and bush housing 44, comprising low friction contact surfaces. The bush housing 44 includes a detent 50 (see FIG. 5), which co-operates with an indent on the bush 42 to allow a limited amount of rotational movement between the bush 42 and bush housing 44 around the longitudinal axis Y. As shown in FIG. 4, the bush 42 comprises an obround aperture 52. The obround aperture 52 will allow for some misalignment between the male locking pin 36 and the centre of the bush 42 whilst still allowing the bush 42 to house the male locking pin 36. The flat portions of the male locking pin 38 and 40 are arranged to contact the flat portions of the obround aperture 52, providing a solid contact surface, and also increasing the surface area of contact between the male locking pin 36 and the bush 42. The contact surfaces of the male locking pin 36 and obround aperture 52 are also arranged to be high friction surfaces, in particular higher friction surfaces than the contact surfaces between the bush 42 and bush housing 44.

(14) The locking mechanism 30 has an unlocked position, in which the male locking pin 36 is not received within the bush 42, and the wing tip device 14 may be moved away from the fixed wing 12, from a flight configuration to a ground configuration. The locking device 30 has a locked position, as shown in FIG. 3, where the male locking pin 36 is located within the bush 42, such that the wing tip device 14 may not be moved relative to the fixed wing 12. In particular, the wing tip device 14 is connected to the fixed wing by a rotational joint, and the movement between the flight configuration and ground configuration is rotational movement. The male locking pin 36, when located in the bush 42, prevents this rotational movement.

(15) In the locked position, as shown in FIG. 3, forces on the fixed wing 12 and wing tip device 14 may cause a relative vibration of the two components. The vibration may result in forces parallel to the longitudinal axis Y being transferred to the locking arrangement 30. The arrangement of the present invention is such that the bush housing 44 and bush 42 provide a low-friction slip path, whereby such vibration results in the relative movement of the bush 42 and bush housing 44 in a direction parallel to the longitudinal axis Y. Therefore, the low-friction slip path reduces or removes the vibrational load which would be experienced by the actuator which drives the male locking pin 36 caused by wing vibration, bending, or twisting. The protection of the actuator in this way means a smaller and/or lighter actuator may be used compared to an actuator which would have to fully tolerate these loads. The reduction or removal of vibrational load between the male locking pin 36 and bush 42 will also reduce the heat created between the two elements, and reduce potential wear of the male locking pin 36 and bush 42.

(16) FIGS. 6 and 7 show the relative positions of the fixed wing 12, the wing tip device 14 and the locking device 30. Also shown in FIGS. 6 and 7 is a slew ring 60, which is described in greater detail in GB 1610105.7. The slew ring 60 comprises an outer race 62 and an inner race 64. The outer race 62 is fixed to the fixed wing 12, such that the outer race 62 remains rotationally stationary relative to the fixed wing 12. The inner race 64 is fixed to the wing tip device 14, such that the inner race 64 remains rotationally stationary relative to the wing tip device 14. The slew ring 60 has axis X around which the wing tip device 14 is moved between the flight and ground configurations. Specifically, the inner race 64 is rotated around the axis X relative to the outer race 62, in order to move the wing tip device between the flight and ground configurations. The movement of the inner race 64 relative to the inner race 62 is controlled and driven by a rotary geared actuator. The locking device 30 is used when the wing tip device 14 is in the flight configuration, to prevent any further rotational movement of the wing tip device 14 around the axis X. The bush 42 forms part of the inner race 64. When the wing tip device 14 is in the flight configuration, the bush 42 is in alignment with the male locking pin 32. The male locking pin 32 is then extended into the bush 42, such that rotational movement of the inner race 64 relative to the outer race 62 is prevented. FIG. 8, being a highly simplified version of FIG. 7, shows an outline of a slew ring 60, and the location of the locking mechanism within the slew ring 60. Only a single locking mechanism 30 is shown, in contrast to the two locking mechanisms shown in FIG. 7. FIG. 8 further shows the orientation of the locking mechanism is such that the obround aperture 52 allows radial displacement of the male locking pin 32, whilst still preventing the rotational movement of the wing tip device 14 around the axis X. Such an arrangement may compensate for thermal expansion or contraction altering the relative positions of the male locking pin 32 and the bush 42.

(17) FIG. 9 shows a schematic view of a rotational joint between a wing tip device and a fixed wing. The rotational joint may comprise a slew ring as described above. The slew ring may connect a wing tip device structural component 92 with a fixed wing structural component 94. Loads on the aircraft wing may result in vibrational, bending, and/or twisting movement of the wing tip device structural component 92 relative to the fixed wing structural component 94. A locking mechanism 30 is associated with the two structural components 92 and 94, such that the locking mechanism 30 may be used to lock the wing tip device structural component 92 in position relative to the fixed wing structural component 94.

(18) Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described.

(19) The aircraft wing may comprise a plurality of locking mechanisms dispersed around a slew ring mechanism. Using a plurality of locking mechanisms may increase the security of the wing tip device when the flight configuration, increasing the strength of the fixed wing and wing tip device and/or providing a level of redundancy in case of failure of one of the locking mechanisms.

(20) Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.