Rotary wing aircraft pitch beam attachment with anti-rotation plate design

Patent metadata

Field	Value
Publication number	US-9441495-B2
Application number	US-201313778741-A
Country	US
Kind code	B2
Filing date	Feb 27, 2013
Priority date	Feb 27, 2013
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A retaining assembly for a tail rotor system is provided including a washer having a plurality of splines. The washer is configured to couple to an adjacent pitch change shaft. A retaining nut includes a self-locking feature and a flange arranged at a first end. The retaining nut is configured to threadably couple to the pitch change shaft such that the flange is in contact with the washer. The flange includes a plurality of first holes configured to at least partially align between the splines of the washer. A lock plate includes a body and a plurality of tabs extending generally perpendicularly from the body. The lock plate is slidably positioned about the pitch change shaft adjacent the flange. The lock plate is operably coupled to the retaining nut and the washer to limit rotational movement thereof relative to the pitch change shaft.

First claim

What is claimed is:

1. A retaining assembly for a tail rotor system, comprising:
a washer including a plurality of splines, the washer being configured to couple to a pitch change shaft;
a retaining nut including a self-locking feature and a flange arranged at a first end, the retaining nut being configured to threadably couple to the pitch change shaft such that the flange is in contact with the washer, wherein the flange includes a plurality of first holes configured to at least partially align between the splines of the washer; and
a lock plate including a body and a plurality of tabs extending generally perpendicularly from the body and extending exteriorly past an outer periphery of the flange and an outer periphery of the washer, the lock plate being slidably positioned about the pitch change shaft adjacent the flange, wherein the lock plate is operably coupled to the retaining nut and the washer to limit rotational movement thereof about the pitch change shaft.

2. The retaining assembly according to claim 1 , wherein a plurality of locking fasteners operably couples the lock plate to the retaining nut and the washer.

3. The retaining assembly according to claim 2 , wherein a wire extends between the plurality of locking fasteners.

4. The retaining assembly according to claim 1 , wherein the body of the lock plate further comprises a plurality of second holes.

5. The retaining assembly according to claim 4 , wherein the plurality of first holes is generally less than the plurality of second holes.

6. The retaining assembly according to claim 5 , wherein each of the plurality of first holes is substantially similar in size to each of the plurality of second holes.

7. The retaining assembly according to claim 1 , wherein at least a portion of the plurality of tabs include an abrasion resistant coating.

8. The retaining assembly according to claim 1 , wherein at least one corner at a free end of each tab is generally rounded.

9. The retaining assembly according to claim 1 , wherein each of the plurality of tabs includes a bend radius such that a free end of each tab does not contact an adjacent surface.

10. A tail rotor system comprising:
a tail rotor hub configured to rotate about an axis;
a plurality of tail rotor blades extending from the tail rotor hub;
a pitch change shaft extending from the tail rotor hub about the axis, the pitch change shaft being configured to translate relative to the tail rotor hub;
a pitch beam disposed at a distal end of the pitch change shaft, the pitch beam including a plurality of arms, each of which is operably coupled to one of the plurality of tail blades to adjust the pitch thereof; and
a retaining assembly configured to couple the pitch beam to the distal end of the pitch change shaft and including:
a washer including a plurality of splines, the washer being configured to couple to the pitch change shaft;
a retaining nut including a flange arranged at a first end, the retaining nut being configured to threadably couple to the pitch change shaft such that the flange contacts the washer, wherein the flange includes a plurality of first holes configured to at least partially align between the splines of the washer; and
a lock plate including a body and a plurality of tabs extending generally perpendicularly from the body, each tab amongst the plurality of tabs extending exteriorly past an outer periphery of the flange and an outer periphery of the washer and within a respective gap between a pair of adjacent arms amongst the plurality of arms of the pitch beam, the lock plate being slidably positioned about the pitch change shaft adjacent the flange, wherein the lock plate is operably coupled to the retaining nut and the washer to limit rotational movement thereof about the pitch change shaft.

11. The tail rotor system according to claim 10 , wherein the body of the lock plate further comprises a plurality of second holes.

12. The tail rotor system according to claim 11 , wherein the plurality of first holes is generally less than the plurality of second holes.

13. The tail rotor system according to claim 11 , wherein the plurality of first holes are substantially similar in size to the plurality of second holes.

14. The tail rotor system according to claim 10 , wherein at least a portion of the plurality of tabs include an abrasion resistant coating.

15. The tail rotor system according to claim 10 , wherein at least one corner at a free end of each tab is generally rounded.

16. The tail rotor system according to claim 10 , wherein each of the plurality of tabs includes a bend radius such that a free end of each tab does not contact an adjacent surface.

17. A method of installing a retaining assembly of a tail rotor system, comprising:
positioning a washer about a first end of a pitch change shaft;
coupling a retaining nut to the first end of the pitch change shaft such that a flange of the retaining nut is in contact with the washer;
positioning a lock plate about the first end of the pitch change shaft in contact with the flange of the retaining nut such that a portion of first holes in the lock plate is generally aligned with a portion of second holes in the flange, and such that a plurality of tabs of the lock plate extend exteriorly past an outer periphery of the flange and an outer periphery of the washer and are positioned respectively within a respective gap between a pair of adjacent arms of a pitch beam disposed on the pitch change shaft; and
operably coupling the lock plate to the retaining nut and the washer.

18. The method according to claim 17 , wherein a self-locking feature of the retaining nut is engaged when the retaining nut is coupled to the pitch change shaft.

19. The method according to claim 17 , wherein a portion of the washer engages a complementary portion of the pitch change shaft to limit relative rotational movement.

Assignees

• Sikorsky Aircraft Corp

Inventors

• Schmaling David N
• Hood Richard Thomas
• Sobel Evan

Classifications

• F16D1/108

  having retaining means rotating with the coupling and acting by interengaging parts, i.e. positive coupling · CPC title

• F16D2001/103

  the torque is transmitted via splined connections · CPC title

• B64C27/82 Primary

  characterised by the provision of an auxiliary rotor or fluid-jet device for counter-balancing lifting rotor torque or changing direction of rotorcraft · CPC title

• F01D7/00 Primary

  Rotors with blades adjustable in operation; Control thereof (for reversing F01D1/30) · CPC title

• Y10T29/49321

  Assembling individual fluid flow interacting members, e.g., blades, vanes, buckets, on rotary support member · CPC title