Droop ring with removable wear elements

Patent metadata

Field	Value
Publication number	US-11235870-B2
Application number	US-201816022375-A
Country	US
Kind code	B2
Filing date	Jun 28, 2018
Priority date	Jun 28, 2018
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

A rotorcraft having a rotor system including a yoke, a plurality of grip assemblies, each of which is hingedly attach a rotor blade to the yoke, a plurality of flap stops, each flap stop attached to a respective grip assembly, a channel bounded by an upper and lower retaining surfaces, and a droop ring slideably disposed in the channel of the droop limiting system. The droop ring has a body with an inner surface, an outer surface, and a first end surface between the inner surface and the outer surface. The droop ring further has a first wear element removably disposed at the first end surface and extending above the first end surface and spaces the first end surface apart from the channel. Each flap stop is arranged to contact the outer surface of the droop ring and limit a downward droop of the respective rotor blade.

First claim

What is claimed is:

1. A rotorcraft having a rotor system, comprising:
a yoke;
a plurality of grip assemblies, each grip assembly of the plurality of grip assemblies hingedly attaching a respective rotor blade of a plurality of rotor blades to the yoke;
a plurality of flap stops, each flap stop of the plurality of flap stops attached to a respective grip assembly of the plurality of grip assemblies;
a droop limiting system having a channel bounded by an upper retaining surface, a lower retaining surface and a stop surface disposed between the upper retaining surface and the lower retaining surface; and
a droop ring slideably disposed in the channel of the droop limiting system, the droop ring having a body with an inner surface, an outer surface, and a first end surface disposed between the inner surface and the outer surface, the droop ring further having a first wear element disposed at the first end surface, wherein the first wear element is removable, and wherein the first wear element extends above the first end surface and spaces the first end surface apart from the channel;
wherein each flap stop of the plurality of flap stops is arranged to contact the outer surface of the droop ring and limit a downward droop of the respective rotor blade;
wherein the body has a ring shape with the outer surface forming an outer edge of the body and extending contiguously in a circle around the entirety of the body, wherein the body has a protective layer disposed on the outer surface of the body, wherein the protective layer is formed from a material different than a material forming the body, and wherein the protective layer extends contiguously in a circle around the entirety of the body; and
wherein a plurality of drain holes are disposed in the droop ring, where each drain hole of the plurality of drain holes extends contiguously from a first recess of the first wear element, through the first wear element, through a center wall of the body, through a second wear element opposite the first wear element, and to a second recess of the second wear element.

2. The rotorcraft of claim 1 , wherein the first end surface has a first cavity, and wherein the first wear element is disposed in the first cavity.

3. The rotorcraft of claim 2 , wherein the body further has a second end surface opposite the first end surface and further has a second cavity with the second wear element disposed in the second cavity, wherein the second wear element spaces the second end surface apart from the channel.

4. The rotorcraft of claim 3 , wherein the first cavity is separated from the second cavity by a center wall.

5. The rotorcraft of claim 4 , the first wear element has a first recess and the second wear element has a second recess, and wherein a fastener extends from the first recess, through a portion of the first wear element, through the center wall, through a portion of the second wear element, into the second cavity.

6. The rotorcraft of claim 2 , wherein an upper surface of the first wear element is disposed above the first end surface, and wherein a first edge of the first wear element bordering the upper surface of the wear element has a chamfer.

7. The rotorcraft of claim 6 , wherein the first cavity has a fillet joining side surfaces of the first cavity to a bottom surface of the first cavity, and wherein the upper surface of the first wear element is disposed above the first end surface, and wherein the first wear element has a relief surface in a bottom edge between a bottom surface of the first wear element and sides of the first wear element, wherein the relief surface is spaced apart from the fillet by a relief space.

8. A droop ring, comprising:
a body having an inner surface, an outer surface, a first end surface disposed between the inner surface and the outer surface, and a second end surface disposed between the inner surface and the outer surface opposite the first end surface, wherein the first end surface has first cavities and the second end surface has second cavities; and
a plurality of wear elements comprising first wear elements removably disposed in the first cavities and second wear elements removably disposed in the second cavities, wherein each of the first wear elements extends from within a respective one of the first cavities past the first end surface and has a first wear surface disposed above the first end surface, and wherein each of the second wear elements extends from within a respective one of the second cavities past the second end surface and has a second wear surface disposed above the second end surface;
wherein the body has a ring shape with the outer surface forming an outer edge of the body and extending contiguously in a circle around the entirety of the body, wherein the body has a protective layer disposed on the outer surface of the body, wherein the protective layer is formed from a material different than a material forming the body, and wherein the protective layer extends contiguously in a circle around the entirety of the body; and
wherein a plurality of drain holes are disposed in the droop ring, where each drain hole of the plurality of drain holes extends contiguously from a first recess of a first respective wear element of the plurality of wear elements, through the first respective wear element, through a center wall of the body, through a second respective wear element of the plurality of wear elements, and to a second recess of the second respective wear element.

9. The droop ring of claim 8 , wherein the body further has center walls, and wherein each of the first cavities is separated from a respective one of the second cavities by a respective one of the center walls.

10. The droop ring of claim 9 , wherein the droop ring further comprises fasteners securing the first wear elements in the first cavities and the second wear elements in the second cavities.

11. The droop ring of claim 10 , wherein each of the fasteners extends from one of the first wear elements, through one of the center walls, into one of the second wear elements.

12. The droop ring of claim 11 , wherein a first end of each of the fasteners extends into a first recess in the first wear surface of a respective one of the first wear elements, and wherein a second end of each of the fasteners extends into a second recess in the second wear surface of a respective one of the second wear elements.

13. The droop ring of claim 8 , wherein the protective layer comprises a first metal, and wherein the body is formed from a second metal different from the first metal.

14. The droop ring of claim 8 , wherein each of the first wear elements has a chamfer at a first edge that borders the respective first wear surface of the respective one of the first wear elements and that extends from an outer surface of the respective first wear element and from at least the first end surface, to above the first end surface, and to a first top surface of the respective first wear element, and wherein each of the second wear elements has a chamfer at a second edge that borders the respective second wear surface of the respective one of the second wear elements and that extends from an outer surface of the respective second wear element and from at least the second end surface, to above the second end surface, and to a second top surface of the respective second wear element.

15. The droop ring of claim 8 , wherein the each of the first cavities has a fillet joining side surfaces of the respective one of the first cavities to a bottom surface of the respective one of the first cavities, and wherein each of the first wear elements has a re

Assignees

• Textron Innovations Inc

Inventors

• Wiinikka Mark Adam
• Ledbetter Matthew Curtis

Classifications

• B23P2700/01

  Aircraft parts · CPC title

• B64C27/322 Primary

  Blade travel limiting devices, e.g. droop stops · CPC title

• B64C27/37

  having articulated joints · CPC title

• B64C27/35

  having elastomeric joints · CPC title