Upper attachment for trimmable horizontal stabiliser actuator

Patent metadata

Field	Value
Publication number	US-10239603-B2
Application number	US-201615080813-A
Country	US
Kind code	B2
Filing date	Mar 25, 2016
Priority date	Mar 26, 2015
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

An upper attachment system for a trimmable horizontal stabilizer actuator (THSA) comprises: a housing, holding a yoke and a ballscrew; a nut coupled to the housing and cooperating with the ballscrew such that rotation of the ballscrew relative to the nut results in linear motion of the ballscrew; a recess formed between the yoke and the ballscrew and arranged to receive, in use, an upper part of a tie bar of the secondary load path of the actuator; and a biasing mechanism arranged such that, in use, when no axial load is applied to the tie bar, the yoke and the ballscrew are held by balanced forces from the biasing mechanism in a position within the recess.

First claim

The invention claimed is:

1. An upper attachment system for a trimmable horizontal stablizer actuator (THSA), the upper attachment comprising:
a housing holding a yoke and a ballscrew;
a nut coupled to the housing and cooperating with the ballscrew such that rotation of the ballscrew relative to the nut results in linear motion of the ballscrew;
a recess formed between the yoke and the ballscrew and arranged to receive, in use, an upper part of a tie bar of the secondary load path of the actuator; and
a biasing mechanism arranged such that, in use, when no axial load is applied to the tie bar, the yoke and the ballscrew are held by balanced forces from the biasing mechanism in a position within the recess, and such that when, in use, an axial load is applied to the yoke by the upper part of the tie bar, the balanced forces from the biasing mechanism are overcome and the axial load along with the biasing mechanism results in linear motion of the ballscrew in a first axial direction relative to the nut, wherein the linear motion moves the ballscrew toward the yoke and closes the recess around the upper part of the tie bar;
wherein the biasing mechanism includes a center spring arranged to provide a force urging the yoke away from the ballscrew.

2. An upper attachment system as claimed in claim 1 , wherein the biasing mechanism includes a lower spring pushing the yoke in an opposite axial direction to the first axial direction.

3. An upper attachment system as claimed in claim 2 , wherein both the center spring and the lower spring and are arranged such that when, in use, there is no axial load from the tie bar the ballscrew is urged upward.

4. An upper attachment system as claimed in claim 1 , wherein the biasing mechanism comprises an upper spring arranged to provide a force urging the ballscrew in the first axial direction.

5. An upper attachment system as claimed in claim 1 , wherein the biasing mechanism comprises: a lower spring pushing the yoke in an opposite axial direction to the first axial direction, and an upper spring arranged to provide a force urging the ballscrew in the first axial direction; wherein the lower spring, the center spring and the upper spring are arranged such that when, in use, no axial load is applied to the yoke or the ballscrew by the tie bar then the ballscrew and the yoke are in stable equilibrium with the recess in its open configuration, and further such that when, in use, an axial load is applied to the yoke by the tie bar the lower spring will be compressed and the forces from the biasing mechanism will become unbalanced so that the ballscrew is urged in the first direction toward the yoke and thereby clamps the upper part of the tie bar, in use, in the recess.

6. An upper attachment system as claimed in claim 1 , wherein the yoke and the ballscrew are arranged with respective upper and lower surfaces forming the recess in a shape for cooperation with the shape of the upper part of the tie bar.

7. An upper attachment system as claimed in claim 1 , wherein the nut is arranged to rotate relative to the housing and the ballscrew.

8. An upper attachment system as claimed in claim 1 , comprising a no back system for preventing reverse rotation of the ballscrew relative to the nut.

9. An upper attachment system as claimed in claim 8 , wherein the no back system is arranged to resist relative rotation of the nut and the ballscrew when an axial load is applied to the ballscrew.

10. An upper attachment system as claimed in claim 8 , wherein the no back system is a friction disc arranged to provide a friction force resisting rotation of the nut.

11. An upper attachment system as claimed in claim 1 , wherein the upper attachment further comprises a locking system to avoid inadvertent actuation of the system.

12. An upper attachment system as claimed in claim 11 , wherein the locking system includes a latch device mounted resiliently between the ballscrew and the housing, and wherein sufficient axial force on the ballscrew will overcome the resilience of the latch device and allow relative axial movement of the ballscrew and the housing.

13. An upper attachment system as claimed in claim 11 , wherein the locking system is arranged to fix the ballscrew in place unless an axial force above a certain threshold is applied.

14. An upper attachment system for a trimmable horizontal stablizer actuator (THSA), the upper attachment comprising:
a housing holding a yoke and a ballscrew;
a nut coupled to the housing and cooperating with the ballscrew such that rotation of the ballscrew relative to the nut results in linear motion of the ballscrew;
a recess formed between the yoke and the ballscrew and arranged to receive, in use, an upper part of a tie bar of the secondary load path of the actuator; and
a biasing mechanism arranged such that, in use, when no axial load is applied to the tie bar, the yoke and the ballscrew are held by balanced forces from the biasing mechanism in a position within the recess, and such that when, in use, an axial load is applied to the yoke by the upper part of the tie bar, the balanced forces from the biasing mechanism are overcome and the axial load along with the biasing mechanism results in linear motion of the ballscrew in a first axial direction relative to the nut, wherein the linear motion moves the ballscrew toward the yoke and closes the recess around the upper part of the tie bar;
comprising a no back system for preventing reverse rotation of the ballscrew relative to the nut, wherein the no back system is a friction disc arranged to provide a friction force resisting rotation of the nut.

15. An upper attachment system for a trimmable horizontal stablizer actuator (THSA), the upper attachment comprising:
a housing holding a yoke and a ballscrew;
a nut coupled to the housing and cooperating with the ballscrew such that rotation of the ballscrew relative to the nut results in linear motion of the ballscrew;
a recess formed between the yoke and the ballscrew and arranged to receive, in use, an upper part of a tie bar of the secondary load path of the actuator; and
a biasing mechanism arranged such that, in use, when no axial load is applied to the tie bar, the yoke and the ballscrew are held by balanced forces from the biasing mechanism in a position within the recess, and such that when, in use, an axial load is applied to the yoke by the upper part of the tie bar, the balanced forces from the biasing mechanism are overcome and the axial load along with the biasing mechanism results in linear motion of the ballscrew in a first axial direction relative to the nut, wherein the linear motion moves the ballscrew toward the yoke and closes the recess around the upper part of the tie bar;
wherein the upper attachment further comprises a locking system to avoid inadvertent actuation of the system; and
wherein the locking system includes a latch device mounted resiliently between the ballscrew and the housing, and wherein sufficient axial force on the ballscrew will overcome the resilience of the latch device and allow relative axial movement of the ballscrew and the housing.

16. An upper attachment system as claimed in claim 15 , wherein the locking system is arranged to fix the ballscrew in place unless an axial force above a certain threshold is applied.

Assignees

• Goodrich Actuation Systems Sas

Inventors

• Medina Raphael
• Abdul-Bari Anh-Vu

Classifications

• B64C5/02

  Tailplanes · CPC title

• F16H25/205 Primary

  comprising alternate power paths, e.g. for fail safe back-up · CPC title

• B64C9/02

  Mounting or supporting thereof · CPC title

• F16H25/2209

  with arrangements for taking up backlash · CPC title

• B64C5/10 Primary

  adjustable · CPC title