Pitch trimmer

Patent metadata

Field	Value
Publication number	US-11014654-B2
Application number	US-201816018809-A
Country	US
Kind code	B2
Filing date	Jun 26, 2018
Priority date	Jun 30, 2017
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

A landing gear assembly (12) includes a primary load bearing strut including a shock absorber having a slider part (15) arranged to slide within a cylinder part (17). A link assembly (50) is attached between the slider part (15) and the cylinder part (17). A bogie (16) supporting wheels is mounted on the strut. The bogie may adopt different pitch angles. A pitch trimmer device (70) is attached to the bogie and to the link assembly, for example thus providing a relatively long moment arm (96) for control of the bogie pitch angle. The arrangement may be such that the pitch trimmer (70) is near mid-stroke as the aircraft achieves the full weight on wheels condition, whereas the pitch trimmer is at a fullest extent for flight case and for retraction. Onset of pitch trimmer closure/movement is used to detect the weight-on-wheels condition.

First claim

The invention claimed is:

1. A landing gear assembly including:
a primary load bearing strut comprising a shock absorber including a slider part arranged to slide within a cylinder part,
a link assembly including a first link member having a first end attached to the cylinder part and a second link member having a first end attached to the slider part, and second ends of the first and second link members are pivotably attached at a hinge;
a bogie configured to support aircraft landing wheels, wherein the bogie is mounted on the primary load bearing strut such that the bogie may adopt different pitch angles, and
a pitch trimmer device arranged to set a pitch angle of the bogie,
wherein the pitch trimmer device is attached at a first end to the bogie and at a second end to the link assembly at, or directly adjacent to, the hinge of the link assembly.

2. The landing gear assembly according to claim 1 , wherein the link assembly is a primary torque link assembly of the landing gear assembly.

3. The landing gear assembly according to claim 1 , wherein the landing gear assembly comprises a further link assembly which attaches at a first end to the slider part and at a second end to the cylinder part, the further link assembly being the primary torque link assembly of the landing gear assembly.

4. The landing gear assembly according to claim 1 , wherein the second end of the pitch trimmer device is attached to the second link member of the link assembly.

5. The landing gear assembly according to claim 1 , wherein the geometry of the landing gear assembly is such that the pitch trimmer device is able, in use, to adopt a position in which a line of action of the pitch trimmer device is at an angle of more than 30 degrees to a longitudinal axis of the bogie.

6. The landing gear assembly according to claim 1 , wherein a geometry of the landing gear assembly enables the pitch trimmer device to adopt a position in which a line of action of the pitch trimmer device is at an angle of more than 30 degrees to a longitudinal axis of the primary load bearing strut.

7. The landing gear assembly according to claim 1 , wherein the landing gear assembly is a retractable landing gear assembly.

8. The landing gear assembly according to claim 7 , further comprising a hydraulic pipe connected to the pitch trimmer and configured to supply hydraulic power to the pitch trimmer to control an angular position of the bogie with respect to the primary load bearing strut.

9. The landing gear assembly according to claim 8 , wherein while the landing gear assembly is in a full weight-on-the aircraft landing wheels configuration, the pitch trimmer device is extended to in or near a midway position between of a stroke length of the pitch trimmer device.

10. The landing gear assembly according to claim 1 , wherein the pitch trimmer device has a length when fully extended that is at least five times a widest diameter of its cylinder.

11. The landing gear assembly according to claim 1 , further comprising a flexible joint providing two degrees of freedom of movement between at least one of (a) the first end of the pitch trimmer device and the bogie and (b) the second end of the pitch trimmer device and the link assembly.

12. A wing assembly comprising the landing gear assembly of claim 1 .

13. An aircraft including the landing gear assembly of claim 1 .

14. An aircraft landing gear assembly including:
a load bearing strut including a shock absorber comprising a slider rod and a cylinder within which slides the slider rod;
a link assembly including a first link member having a first end attached to the cylinder of the load bearing strut and a second link member having a first end attached to the slider rod of the load bearing strut, and second ends of the first and second link members are pivotably attached at a hinge;
a bogie supporting aircraft landing wheels, wherein a center region of the bogie is pivotably mounted to the slider rod, and
a pitch trimmer configured to set a pitch angle for the bogie, the pitch trimmer including a first end directly attached to a position on the bogie spaced from the center region of the bogie, and a second end directly attached to the hinge or to one of the first and second link members proximate to the hinge.

15. The aircraft landing gear assembly of claim 14 , wherein the aircraft landing wheels includes at least one wheel proximate a rear end region of the bogie and at least one wheel proximate a front end region of the bogie, and the position on the bogie to which the second end of the pitch trimmer is directly attached is the rear end region or the front end region.

16. The aircraft landing gear assembly of claim 14 , wherein the pitch trimmer includes a cylinder and a rod slidably within the cylinder along an axis of the pitch trimmer, wherein the second end of the pitch trimmer is an end of the cylinder of the pitch trimmer, and the first end of the pitch trimmer is an end of the rod of the pitch trimmer.

17. The aircraft landing gear assembly of claim 14 , wherein the position on the link assembly to which the second end of the pitch trimmer is directly attached is an apex of the link assembly.

Assignees

• Airbus Operations Ltd

Inventors

• Thompson Robert Ian

Classifications

• B64C25/36

  Arrangements or adaptations of wheels, tyres or axles in general · CPC title

• B64C2025/006

  Landing gear legs comprising torque arms · CPC title

• B64C25/60

  Oleo legs · CPC title

• B64C25/34 Primary

  wheeled type, e.g. multi-wheeled bogies · CPC title

• B64D45/0005

  Devices specially adapted to indicate the position of a movable element of the aircraft, e.g. landing gear · CPC title