# US 12,759,693 B2 · Propeller assembly > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,759,693 B2 - Document ID: US12759693B2 - Status: Granted - Kind: B2 - Application number: 19/053,469 - Filed: 2025-02-14 - Published: 2025-09-18 - Granted: 2026-10-13 - Earliest claimed: 2024-03-14 - Assignees: Ratier-Figeac SAS - Applicants: Ratier-Figeac SAS - Inventors: Bruno Seminel - Web page: https://patentgrep.com/patent/US12759693B2 ## CPC - B64C 11/008: {characterised by vibration absorbing or balancing means} - B64C 11/385: {comprising feathering, braking or stopping systems} - B64C 11/44: electric - B64C: AEROPLANES; HELICOPTERS ## Abstract A variable pitch aircraft propeller assembly includes: a plurality of propeller blades and at least one counter-weight arrangement mounted on a propeller blade. The counter-weight arrangement comprises: a first counter-weight and a second counter-weight. The counter-weights are arranged such that when the propeller blade is in fine pitch, the counter-weights are in a first position with respect to the plane of rotation of said propeller blade, and when the propeller blade is substantially feathered, the counter-weights are in a second position with respect to the plane of rotation of said propeller blade. The counter-weights are aligned such that a line drawn between the center of mass of the first counter-weight and the center of mass of the second counter-weight is substantially perpendicular to a longitudinal axis of the propeller blade. ## Claims ### Claim 1 A variable pitch aircraft propeller assembly comprising: a plurality of propeller blades each configured to rotate in a plane of rotation so as to generate thrust in a direction perpendicular to the plane of rotation, wherein each propeller blade of the plurality of propeller blades is configured to be linked to an actuator which controls the pitch of each propeller blade of the plurality of propeller blades, wherein the propeller assembly includes at least six propeller blades; and at least one counter-weight arrangement mounted on at least one propeller blade of the plurality of propeller blades, the at least one counter-weight arrangement comprising: a first counter-weight; and a second counter-weight; wherein the first and second counter-weights are arranged such that when the at least one propeller blade is in fine pitch, the counter-weights are in a first position with respect to the plane of rotation of the at least one propeller blade, and when the at least one propeller blade is substantially feathered, the at least one counter-weights are in a second position with respect to the plane of rotation of said propeller blade; and wherein the counter-weights are aligned such that a line drawn between the center of mass of the first counter-weight and the center of mass of the second counter-weight is perpendicular to a longitudinal axis of the propeller blade; and wherein the counter-weights are arranged only on every other propeller blade. ### Claim 2 (depends on 1) The variable pitch propeller assembly as claimed in claim 1, wherein the second position is closer to the plane of rotation than the first position. ### Claim 3 (depends on 1) The variable pitch propeller assembly as claimed in claim 1, wherein the counter-weights are aligned such that the line drawn between the center of mass of the first counter-weight and the center of mass of the second counter-weight perpendicularly bisects the longitudinal axis of the propeller blade. ### Claim 4 (depends on 1) The variable pitch aircraft propeller assembly as claimed in claim 1, wherein the counter-weight arrangement comprises a first arm protruding from the propeller blade and comprising the first counter-weight mounted thereon, and a second arm protruding from the propeller blade and comprising the second counter-weight mounted thereon. ### Claim 5 (depends on 1) The variable pitch aircraft propeller assembly as claimed in claim 1, wherein the assembly comprises an even number of propeller blades, and wherein every other propeller blade has a counter-weight arrangement mounted thereon. ### Claim 6 (depends on 1) The variable pitch aircraft propeller assembly as claimed in claim 1, wherein the counter-weight arrangement is symmetrical about the longitudinal axis of the propeller blade on which it is mounted. ### Claim 7 (depends on 1) The variable pitch aircraft propeller assembly as claimed in claim 1, wherein each of the plurality of propeller blades is configured to be linked to a common actuator. ### Claim 8 (depends on 1) The variable pitch aircraft propeller assembly as claimed in claim 1, wherein the counter-weights comprise a material having a density between 15 and 20 g/cm3. ### Claim 9 (depends on 1) The variable pitch aircraft propeller assembly as claimed in claim 1, in combination with one or more actuators configured to adjust a pitch of one or more of the propeller blades. ### Claim 10 (depends on 9) A system as claimed in claim 9, comprising a common actuator configured to adjust the pitch of each of the propeller blades. ### Claim 11 (depends on 10) The system as claimed in claim 10, wherein the actuator is bi-directional. ### Claim 12 (depends on 11) The system as claimed in claim 11, wherein the actuator system is configured to provide sufficient force to substantially feather the propeller blades in the event of a single blade counter-weight arrangement failure or loss. ### Claim 13 (depends on 9) The system as claimed in claim 9, wherein at least one of the one or more actuators is a hydraulic actuator. ### Claim 14 (depends on 9) The system as claimed in claim 9, wherein at least one of the one or more actuators is an electrical actuator. ### Claim 15 A counter-weight arrangement for use in a variable pitch propeller assembly comprising a plurality of blades configured to rotate in a common plane of rotation so as to generate thrust in a direction perpendicular to the plane of rotation, the counter-weight arrangement comprising: a first counter-weight; and a second counter-weight; wherein the counter-weights are arranged such that when the counter-weight arrangement is installed on a propeller blade, and the propeller blade is in fine pitch, the counter-weights are in a first position with respect to the common plane of rotation, and when the propeller blade is substantially feathered, the counter-weights are in a second position with respect to the plane of rotation, wherein the counter-weights are aligned such that a line drawn between the center of mass of the first counter-weight and the center of mass of the second counter-weight is perpendicular to a longitudinal axis of the propeller blade; and wherein the counter-weights are arranged only on every other propeller blade; wherein the propeller assembly includes at least six propeller blades.