# US 11,027,831 B2 · Safety rotor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,027,831 B2 - Document ID: US11027831B2 - Status: Granted - Kind: B2 - Application number: 16/315,431 - Filed: 2016-07-08 - Published: 2019-07-18 - Granted: 2021-06-08 - Earliest claimed: 2015-07-10 - Assignees: The University of Queensland - Applicants: The University of Queensland - Inventors: Pauline Edith Iyan Pounds - Web page: https://patentgrep.com/patent/US11027831B2 ## CPC - B64C 27/006: {Safety devices} - A63H 27/12: {Helicopters (A63H27/04 takes precedence); Flying tops} - B64C 11/00: Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft - B64U 30/299: Rotor guards (ducted or shrouded rotors B64U30/26; guards used as ground propulsion B64U60/60) - B64U 50/19: using electrically powered motors - B64U 10/13: Flying platforms - B64U 10/25: Fixed-wing aircraft (VTOL aircraft B64U10/20) - B64U 30/20: Rotors; Rotor supports - B64C: AEROPLANES; HELICOPTERS - A63H: TOYS, e.g. TOPS, DOLLS, HOOPS OR BUILDING BLOCKS - B64U: UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR ## Abstract A safety rotor system for an aircraft including a flight rotor that is rotationally driven by a drive, the system including: a safety rotor that is rotationally driven during rotation of the flight rotor, the safety rotor including one or more safety members traversing a path outward of the flight rotor so that an object approaching the flight rotor through the path contacts one of the safety members before contacting the flight rotor, wherein the safety rotor decelerates when one of the safety members contacts an object; a sensor for detecting rotation of the safety rotor; and a controller configured to: determine, using the sensor, a deceleration of the safety rotor corresponding to one of the safety members contacting an object; and cause the rotation of the flight rotor to cease in response to detecting the deceleration of the safety rotor. ## Claims ### Claim 1 A safety rotor system for an aircraft including a flight rotor that is rotationally driven by a drive, the system including: a) a safety rotor that is rotationally driven during rotation of the flight rotor, the safety rotor including one or more safety members traversing a path outward of the flight rotor so that an object approaching the flight rotor through the path contacts one of the safety members before contacting the flight rotor, wherein the safety rotor decelerates when one of the safety members contacts an object; b) a sensor for detecting rotation of the safety rotor; and, c) a controller configured to: i) determine, using the sensor, a deceleration of the safety rotor corresponding to one of the safety members contacting an object; and, ii) cause the rotation of the flight rotor to cease in response to detecting the deceleration of the safety rotor. ### Claim 2 (depends on 1) A system according to claim 1, wherein the path is radially outward of the flight rotor. ### Claim 3 (depends on 1) A system according to claim 1, wherein the path defines a swept surface covering at least a portion of a rotor disc defined by the flight rotor so that an object passing through the swept surface contacts one of the safety members before contacting the flight rotor. ### Claim 4 (depends on 3) A system according to claim 3, wherein each safety member is configured so that at least one of: a) the swept surface covers at least one of: i) a side of the rotor disc; ii) an edge of the rotor disc; and, iii) both sides of the rotor disc; and, b) the swept surface substantially encloses the rotor disc. ### Claim 5 (depends on 1) A system according to claim 1, wherein the safety rotor is coupled to a shaft using a coupling that allows the safety rotor to be rotationally driven during rotation of the shaft, the coupling permitting the safety rotor to decelerate relative to the shaft when one of the safety members contacts an object. ### Claim 6 (depends on 5) A system according to claim 5, wherein the flight rotor is mounted on the shaft, the shaft being rotationally driven by the drive. ### Claim 7 (depends on 5) A system according to claim 5, wherein the shaft is rotationally driven by a safety rotor drive separate from the drive for driving the flight rotor and the flight rotor is mounted on a flight rotor shaft separate from the shaft to which the safety rotor is coupled, the flight rotor shaft being rotationally driven by the drive. ### Claim 8 (depends on 7) A system according to claim 7, wherein the controller is configured to cause the safety rotor drive to rotate when the drive is driving the flight rotor shaft. ### Claim 9 (depends on 5) A system according to claim 5, wherein the coupling allows the safety rotor to be rotationally driven by a frictional transmission of torque from the shaft and permits the safety rotor to slip relative to the shaft when one of the safety members contacts an object. ### Claim 10 (depends on 9) A system according to claim 9, wherein the coupling includes a spring for biasing a safety rotor surface into engagement with a driven surface such that the frictional transmission of torque is increased due to spring pressure. ### Claim 11 (depends on 10) A system according to claim 10, wherein the spring is mounted coaxially on the shaft, the spring being compressed between a hub of the safety rotor and the flight rotor, and the driven surface being a shoulder of the shaft. ### Claim 12 (depends on 5) A system according to claim 5, wherein the safety rotor includes a hub for coupling the safety rotor to the shaft, each safety member being connected to the hub. ### Claim 13 (depends on 12) A system according to claim 12, wherein at least one of: a) each safety member extends radially from the hub beyond an edge of a rotor disc defined by the flight rotor, b) each safety member includes an outer portion extending at least partially around the edge of the rotor disc; and, c) the hub and the one or more safety members are formed integrally. ### Claim 14 (depends on 12) A system according to claim 12, wherein the safety rotor includes a first hub for coupling the safety rotor to the shaft on a first side of the flight rotor and a second hub for coupling the safety rotor to the shaft on an opposing second side of the flight rotor, each safety member being connected to the first hub and the second hub. ### Claim 15 (depends on 14) A system according to claim 14, wherein one of the hubs is used to rotationally drive the safety rotor during rotation of the shaft and the other one of the hubs is rotationally decoupled from the shaft. ### Claim 16 (depends on 14) A system according to claim 14, wherein each safety member defines a closed loop extending around the rotor disc between the first hub and the second hub, each safety member being configured to maintain a minimum clearance distance between the loop and the rotor disc during rotation of the shaft. ### Claim 17 (depends on 5) A system according to claim 5, wherein at least one of: a) the drive is an electric motor and the controller is configured to cause the electric motor to apply electro-dynamic braking to the shaft in response to detecting the decrease in rotational velocity of the safety rotor; and, b) the system includes a braking device coupled to the shaft and the controller is configured to cause the braking device to apply a braking force to the shaft in response to detecting the decrease in rotational velocity of the safety rotor. ### Claim 18 (depends on 1) A system according to claim 1, wherein each safety member is one of: a) sufficiently rigid so that a shape of the safety member at rest is substantially maintained during rotation; and, b) flexible so that the safety member adopts a different shape during rotation compared to a shape of the safety member at rest. ### Claim 19 (depends on 1) A system according to claim 1, wherein the sensor includes at least one of: a) an optical sensor; b) an electromagnetic sensor; c) a capacitive sensor; and, d) a strain sensor. ### Claim 20 (depends on 1) A system according to claim 1, wherein at least one of: a) at least one of the safety members includes a trigger element for triggering the sensor each time the safety member moves past the sensor during rotation; and, b) the controller is integrated with a processing device of the aircraft that controls operation of the drive.