Friction bushing

Patent metadata

Field	Value
Publication number	US-9995336-B2
Application number	US-201615274142-A
Country	US
Kind code	B2
Filing date	Sep 23, 2016
Priority date	Mar 18, 2014
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

In a preferred embodiment a friction bushing is configured to rotate a shaft with resistance having a housing with a bore to receive the shaft; a flange plate positioned on the housing around the bore; and a number of flanges that protrude axially from the flange plate to receive the shaft, where the flanges generate a radially-directed force by being flexible from a relaxed radius to a shaft radius of the shaft, and the flanges have internal circumferentially spaced surfaces in contact with an external surface of the shaft having a topology to control the resistance as the shaft rotates in the friction bushing.

First claim

What is claimed is:

1. A friction bushing to provide resistance to a rotating shaft, comprising:
a housing having a bore to receive the shaft;
a flange plate positioned on the housing around the bore; and
a plurality of flanges that protrudes axially from the flange plate to receive the shaft, wherein the plurality of flanges generates a radially-directed force by being flexible from a relaxed radius to a shaft radius of the shaft, the plurality of flanges has internal circumferentially spaced surfaces in contact with an external surface of the shaft having a topology to control the resistance as the shaft rotates in the friction bushing, the topology of the external surface of the shaft includes a plurality of regular lobes to control the resistance by providing regular incremental steps as the shaft rotates in the friction bushing and further wherein each regular lobe of the plurality of regular lobes has a predetermined regular lobe width between 10% and 110% of the difference between the relaxed radius and the shaft radius of the shaft; a predetermined regular lobe height between 50% and 80% of the shaft radius, a predetermined inter regular lobe distance between 50 % and 80 % of the shaft radius, and a predetermined regular lobe number between 4 and 8.

2. The friction bushing of claim 1 , wherein the topology of the external surface of the shaft includes a plurality of ratchets to provide a unique direction of rotation for the shaft.

3. The friction bushing of claim 2 , wherein each ratchet of the plurality of ratchets includes a rounded portion to facilitate a passage of the plurality of flanges and a flat portion to prevent the passage of the plurality of the flanges.

4. A friction bushing to provide resistance to a rotating shaft, comprising:
a housing having a bore to receive the shaft;
a flange plate positioned on the housing around the bore; and
a plurality of flanges that protrudes axially from the flange plate to receive the shaft, wherein the plurality of flanges generates a radially-directed force by being flexible from a relaxed radius to a shaft radius of the shaft, the plurality of flanges has internal circumferentially spaced surfaces in contact with an external surface of the shaft having a topology to control the resistance as the shaft rotates in the friction bushing; the topology of the external surface of the shaft including a plurality of ratchets to provide a unique direction of rotation for the shaft, each ratchet of the plurality of ratchets includes a rounded portion to facilitate a passage of the plurality of flanges and a flat portion to prevent the passage of the plurality of the flanges, and wherein each ratchet includes a predetermined ratchet lobe width between 10% and 110% of the difference between the relaxed radius and the shaft radius; a predetermined ratchet lobe height between 50% and 80% of the shaft radius; a predetermined inter ratchet lobe distance between 50% and 80% of the shaft radius; and a predetermined ratchet lobe number between 4 and 8.

5. The friction bushing of claim 4 , wherein the topology of the external surface of the shaft includes a plurality of irregular lobes to control the resistance by providing irregular incremental steps as the shaft rotates in the friction bushing.

6. The friction bushing of claim 4 , wherein each flange of the plurality of flange includes an enlarged terminal portion.

7. A friction bushing to rotate a shaft with resistance, comprising:
a housing having a bore to receive the shaft;
a flange plate positioned on the housing around the bore; and
a plurality of flanges that protrudes axially from the flange plate to receive the shaft, wherein the plurality of flanges generates a radially-directed force by being flexible from a relaxed radius to a shaft radius of the shaft, and the plurality of flanges has internal circumferentially spaced surfaces in contact with an external surface of the shaft having a texture to control the resistance as the shaft rotates in the friction bushing; further wherein the texture of the external surface of the shaft includes a plurality of axial texture bands to control the resistance by providing alternative frictional levels as the shaft rotates in the friction bushing and further wherein each axial texture band of the plurality of axial texture bands includes a predetermined axial band thickness between 10% and 110% of an axial length of the plurality of flanges; a predetermined axial band inter distance between 10% and 110% of the axial length of the plurality of flanges, and a predetermined axial band roughness between 0.05 1 μm and 50 μm.

8. The friction bushing of claim 7 , wherein the texture of the external surface of the shaft includes a circumferential band to control the resistance by providing a constant friction level as the shaft rotates in the friction bushing.

9. The friction bushing of claim 8 , wherein the circumferential band includes a predetermined circumferential band thickness between 10% and 110% of an axial length of the plurality of flanges; and a predetermined circumferential band roughness between 0.05 μm and 50 μm.

10. The friction bushing of claim 7 , wherein each flange of the plurality of flange includes an enlarged terminal portion.

Assignees

• Be Aerospace Inc

Inventors

• Garing Francis Xavier
• Stephens Benjamin D
• Kruse Mark A

Classifications

• F16C27/02 Primary

  Sliding-contact bearings · CPC title

• F16C2326/43

  Aeroplanes; Helicopters · CPC title

• B60N3/004

  of foldable trays mounted on the back-rest · CPC title

• B60N2/682

  Joining means · CPC title

• F16D7/021

  with radially applied torque-limiting friction surfaces (F16D7/022 takes precedence) · CPC title