Feathering propeller clutch mechanisms

Patent metadata

Field	Value
Publication number	US-2017166302-A1
Application number	US-201514966493-A
Country	US
Kind code	A1
Filing date	Dec 11, 2015
Priority date	Dec 11, 2015
Publication date	Jun 15, 2017
Grant date	—

Abstract

Aerial vehicles may be equipped with propellers having clutch mechanisms that contract around a shaft when the propellers are not rotating, or are rotating at low angular velocities, and expand around the shaft when the propellers are rotating at sufficiently high angular velocities. The clutch mechanisms may receive one or more fixed posts within an opening or window defined therein. When the clutch mechanisms contract into a closed position, components of the clutch mechanisms come into contact with the posts, and the propellers are forced to remain in an alignment defined by the posts. When the clutch mechanisms expand into an open position, such components may rotate freely without contacting the posts. Thus, a clutch mechanism may cause a propeller to remain aligned in a desired orientation when the propeller is not required for operation, thereby reducing drag or adverse acoustic effects.

First claim

What is claimed is:

1 . An unmanned aerial vehicle comprising:
a frame; a base mounted to the frame, wherein the base comprises a platform having an opening and at least one post extending vertically upward from the platform; a motor mounted to the frame beneath the base, wherein the motor comprises a shaft extending through the opening of the platform; a propeller mounted to a distal end of the shaft; and a clutch mechanism mounted to a first side of the propeller, wherein the clutch mechanism further comprises:
a first feathering arm pivotably mounted to the first side of the propeller by a first fastener, wherein the first feathering arm is adapted to pivot about the first fastener between a first position proximate the at least one post and a second position remote from the at least one post;
a second feathering arm pivotably mounted to the first side of the propeller by a second fastener, wherein the second feathering arm is adapted to pivot about the second fastener between a third position proximate the at least one post and a fourth position from the at least one post;
a first biasing element mounted to the first side of the propeller, wherein the first biasing element is configured to apply a first biasing force urging the first feathering arm into the first position to at least a first portion of the first feathering arm; and
a second biasing element mounted to the first side of the propeller, wherein the second biasing element is configured to apply a second biasing force urging the second feathering arm into the third position to at least a second portion of the second feathering arm,
wherein the first feathering arm is configured to pivot into the second position when an angular velocity of the propeller exceeds a first predetermined threshold, and wherein the second feathering arm is configured to pivot into the fourth position when the angular velocity of the propeller exceeds the first predetermined threshold.

2 . The unmanned aerial vehicle of claim 1 , wherein the at least one post defines an axis, and
wherein the clutch mechanism is aligned along the axis when the first feathering arm is in the first position and when the second feathering arm is in the third position.

3 . The unmanned aerial vehicle of claim 1 ,
wherein at least one of the first feathering arm or the second feathering arm is aligned to contact the at least one post when the first feathering arm is in the first position or when the second feathering arm is in the third position, and wherein neither the first feathering arm nor the second feathering arm is aligned to contact the at least one post when the first feathering arm is in the second position and when the second feathering arm is in the fourth position.

4 . The unmanned aerial vehicle of claim 1 , wherein the first feathering arm comprises a first weighted end and a first tapered end provided at an obtuse angle with respect to the first weighted end, and
wherein the second feathering arm comprises a second weighted end and a second tapered end provided at the obtuse angle with respect to the second weighted end.

5 . The unmanned aerial vehicle of claim 4 , wherein the first biasing element is a first tension spring mounted to the first weighted end and the second fastener, and
wherein the second biasing element is a second tension spring mounted to the second weighted end and the first fastener.

6 . A propeller comprising:
a shaft; and a clutch mechanism provided around the shaft, wherein the clutch mechanism further comprises:
at least one arm pivotably mounted to a first surface of the propeller, wherein the at least one arm is configured to pivot between a first position proximate the shaft and a second position remote from the shaft; and
at least one biasing element applying a biasing force urging the at least one arm into the first position.

7 . The propeller of claim 6 , wherein the at least one arm is pivotably mounted to the first surface of the propeller by a pivotable fastener, and
wherein the at least one arm comprises a weighted end and a tapered end provided at an obtuse angle with respect to the weighted end, and wherein a first mass of the weighted end exceeds a second mass of the tapered end.

8 . The propeller of claim 7 , wherein the at least one biasing element applies the biasing force to the weighted end.

9 . The propeller of claim 8 , wherein a centrifugal force on the weighted end exceeds the biasing force when an angular velocity of the propeller exceeds a predetermined threshold.

10 . The propeller of claim 7 , wherein the clutch mechanism is configured to contact at least one post when the at least one arm is in the first position, and
wherein the clutch mechanism is configured to rotate without contacting the at least one post when the at least one arm is in the second position.

11 . The propeller of claim 6 , further comprising an attachment plate joined to the first surface of the propeller,
wherein the at least one arm is pivotably mounted to the attachment plate.

12 . The propeller of claim 11 , further comprising a mechanical stop mounted to the attachment plate,
wherein the mechanical stop is aligned to inhibit the at least one arm from pivoting beyond the second position.

13 . The propeller of claim 6 , wherein the at least one arm is formed of at least one of:
a metal; a plastic; a wood; or a composite material.

14 . The propeller of claim 6 , wherein the at least one biasing element is at least one of:
a tension spring; a compression spring; an extension spring; a torsion spring; a leaf spring; or a constant force spring.

15 . The propeller of claim 6 , wherein the at least one arm comprises a first arm having a first weighted end and a first tapered end provided at an obtuse angle with respect to the first weighted end and a second arm having a second weighted end and a second tapered end provided at the obtuse angle with respect to the second weighted end, and
wherein the first arm is pivotably mounted to the first surface of the propeller by a first pivotable fastener and the second arm is pivotably mounted to the first surface of the propeller by a second pivotable fastener.

16 . The propeller of claim 15 , wherein the at least one biasing element comprises a first biasing element joined to the first weighted end and the second fastener and a second biasing element joined to the second weighted end and the first fastener,
wherein the first biasing element applies a first biasing force to the first weighted end and the second biasing element applies a second biasing force to the second weighted end.

17 . A method to operate an aerial vehicle comprising:
initiating an operation of a first motor having a first propeller coupled thereto, wherein the aerial vehicle comprises a first post and a second post defining an axis aligned between the first motor and the first propeller, wherein the first propeller comprises a first clutch mechanism having at least a first arm for defining one of an open position or a closed position of the first clutch mechanism, and at least one biasing element for urging at least the first arm to define the closed position of the first clutch mechanism, wherein at least a portion of the first clutch mechanism is aligned to contact the first post or the second post when the first clutch mechanism is in the closed position, and wherein the first clutch mechanism is aligned to rotate without contact with the first post or the second post when the first clutch mechanism is in

Assignees

• Amazon Tech Inc

Inventors

• Shiosaki Dominic Timothy

Classifications

• B64D35/00

  Transmitting power from power plants to propellers or rotors; Arrangements of transmissions · CPC title

• B64C27/32

  Rotors · CPC title

• B64C11/325

  comprising feathering, braking or stopping systems · CPC title

• B64C27/14 Primary

  Direct drive between power plant and rotor hub · CPC title

• B64C11/06

  for variable-pitch blades · CPC title