Propeller assemblies, aircraft including the same, and associated methods

Patent metadata

Field	Value
Publication number	US-11401031-B2
Application number	US-202016791311-A
Country	US
Kind code	B2
Filing date	Feb 14, 2020
Priority date	Feb 14, 2020
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

Propeller assemblies, aircraft including the same, and associated methods. A propeller assembly includes a first propeller and a second propeller operatively coupled to a coupling shaft and configured to pivot with respect to one another about a propeller rotation axis. The propeller assembly additionally includes a coupling assembly operatively coupled to the first propeller and the second propeller and configured to transition between a plurality of pivotal configurations defined between and including a stowed configuration and a deployed configuration. The coupling assembly transitions from the stowed configuration toward the deployed configuration when a coupling assembly rotational velocity rises above a threshold stowed rotational velocity. In examples, an aircraft includes one or more propeller assemblies operatively coupled to a fuselage. In some examples, a method of operating a propeller assembly includes automatically transitioning a coupling assembly of the propeller assembly between a stowed configuration and a deployed configuration.

First claim

The invention claimed is:

1. A propeller assembly, comprising:
a coupling shaft that extends along a propeller rotation axis;
a plurality of stacked propellers including at least a first propeller and a second propeller that are configured to pivot with respect to one another about the propeller rotation axis, each of the first propeller and the second propeller being operatively coupled to the coupling shaft and including a propeller hub and two propeller blades extending radially away from the propeller hub, each propeller blade extending along a respective blade longitudinal axis; and
a coupling assembly operatively coupled to each of the first propeller and the second propeller and configured to rotate about the propeller rotation axis;
wherein the coupling assembly is configured to transition between a plurality of pivotal configurations;
wherein each of the plurality of pivotal configurations is characterized by a blade offset angle defined between the blade longitudinal axis of a given propeller blade of the first propeller and the blade longitudinal axis of a corresponding propeller blade of the second propeller and as measured in a plane perpendicular to the propeller rotation axis;
wherein the coupling assembly is constrained to assume a configuration among the plurality of pivotal configurations defined between and including a stowed configuration, in which the blade offset angle is a minimum blade offset angle, and a deployed configuration, in which the blade offset angle is a maximum blade offset angle that is greater than the minimum blade offset angle, wherein the maximum blade offset angle is at least 30 degrees and at most 90 degrees;
wherein the coupling assembly is in the deployed configuration when a coupling assembly rotational velocity of the coupling assembly about the propeller rotation axis is at or above a threshold deployed rotational velocity;
wherein the coupling assembly is in the stowed configuration when the coupling assembly rotational velocity is at or below a threshold stowed rotational velocity; and
wherein the coupling assembly is configured to transition from the stowed configuration toward the deployed configuration when the coupling assembly rotational velocity rises above the threshold stowed rotational velocity.

2. The propeller assembly of claim 1 , wherein the coupling assembly is configured to transition from the deployed configuration toward the stowed configuration when the coupling assembly rotational velocity falls below the threshold deployed rotational velocity.

3. The propeller assembly of claim 1 , wherein the coupling assembly includes:
a first propeller mount that is fixedly coupled to the first propeller;
a second propeller mount that is fixedly coupled to the second propeller; and
a plurality of mount coupling mechanisms, each mount coupling mechanism operatively interconnecting the first propeller mount and the second propeller mount;
wherein each of the first propeller mount and the second propeller mount includes:
a respective mount hub that is coaxial with the propeller rotation axis; and
a respective plurality of mount arms extending radially away from the mount hub.

4. The propeller assembly of claim 3 , wherein each mount coupling mechanism of the plurality of mount coupling mechanisms includes:
a first coupling arm that is pivotally coupled to a corresponding mount arm of the plurality of mount arms of the first propeller mount such that the first coupling arm is configured to pivot relative to the corresponding mount arm about a first coupling pivot axis;
a second coupling arm that is pivotally coupled to a corresponding mount arm of the plurality of mount arms of the second propeller mount such that the second coupling arm is configured to pivot relative to the corresponding mount arm about a second coupling pivot axis; and
a mount pivotal coupler that pivotally interconnects the first coupling arm and the second coupling arm such that the first coupling arm and the second coupling arm are configured to pivot relative to one another about a mount pivot axis.

5. The propeller assembly of claim 4 , wherein the coupling assembly further includes a coupling assembly stop mechanism that is configured to restrict the coupling assembly from assuming a pivotal configuration that is outside of a range of pivotal configurations defined between and including the stowed configuration and the deployed configuration; wherein the coupling assembly stop mechanism includes a coupling assembly guide member that is configured to engage a portion of each mount coupling mechanism of the plurality of mount coupling mechanisms when the coupling assembly is in at least one of the plurality of pivotal configurations; wherein the coupling assembly guide member includes a plurality of slotted guide arms extending radially away from the propeller rotation axis; and wherein each slotted guide arm of the plurality of slotted guide arms defines a slot that terminates at a slot outer stop that is distal the propeller rotation axis.

6. The propeller assembly of claim 5 , wherein the mount pivotal coupler of each mount coupling mechanism of the plurality of mount coupling mechanisms travels within the slot of a corresponding slotted guide arm of the plurality of slotted guide arms as the coupling assembly transitions among the plurality of pivotal configurations; and wherein, when the coupling assembly is in the deployed configuration, the mount pivotal coupler of each mount coupling mechanism of the plurality of mount coupling mechanisms engages the slot outer stop of the slot of the corresponding slotted guide arm of the plurality of slotted guide arms.

7. The propeller assembly of claim 5 , wherein, when the coupling assembly is in the deployed configuration, the first coupling pivot axis, the second coupling pivot axis, and the mount pivot axis are at least substantially coplanar.

8. The propeller assembly of claim 5 , wherein the coupling assembly includes one or more return springs, each return spring of the one or more return springs being operatively coupled to one or both of the first propeller mount and the second propeller mount to bias the coupling assembly toward the stowed configuration; wherein the coupling assembly includes at least one return mechanism that biases the coupling assembly toward the stowed configuration; and wherein each return mechanism of the at least one return mechanism includes at least one of the one or more return springs.

9. The propeller assembly of claim 8 , wherein each return mechanism of the at least one return mechanism further includes:
a first return arm that is pivotally coupled to the first propeller mount such that the first return arm is configured to pivot relative to the first propeller mount about a first return pivot axis;
a second return arm that is pivotally coupled to the second propeller mount such that the second return arm is configured to pivot relative to the second propeller mount about a second return pivot axis; and
a return pivotal coupler that pivotally interconnects the first return arm and the second return arm such that the first return arm and the second return arm are configured to pivot relative to one another about a return arm pivotal axis; and
wherein each return spring of the one or more return springs is operatively coupled to two components selected from the group consisting of:
(i) the first return arm of a corresponding return mechanism of the at least one return mechanism;
(ii) the first coupling arm of a corresponding mount coupling mechanism of the plurality of mount coupling mechanisms;
(iii) the first propeller mount;
(iv) the second return arm of a corresponding return mechanism of the at least one

Assignees

• Aurora Flight Sciences Corp

Inventors

• Ensslin Oliver Daniel

Classifications

• B64C11/48

  Units of two or more coaxial propellers · CPC title

• B64C11/04

  Blade mountings · CPC title

• B64C27/473 Primary

  Constructional features · CPC title

• B64C27/37

  having articulated joints · CPC title

• B64C27/51

  Damping of blade movements · CPC title