# US 12,215,000 B2 · Method and yoke for lifting a wind turbine component > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,215,000 B2 - Document ID: US12215000B2 - Status: Granted - Kind: B2 - Application number: 17/777,782 - Filed: 2020-06-18 - Published: 2023-03-16 - Granted: 2025-02-04 - Earliest claimed: 2019-06-24 - Assignees: Liftra IP Aps - Applicants: Liftra IP Aps - Inventors: Per E. Fenger; Alexander Becsei Christiansen - Web page: https://patentgrep.com/patent/US12215000B2 ## CPC - B66C 13/46: Position indicators for suspended loads or for crane elements - B66C 1/108: {for lifting parts of wind turbines} - B66C 1/42: Gripping members engaging only the external or internal surfaces of the articles (for handling or stripping castings or ingots during manufacture B22D29/00) - B66C 1/62: comprising article-engaging members of a shape complementary to that of the articles to be handled - B66C 13/08: for depositing loads in desired attitudes or positions - F03D 13/10: Assembly of wind motors; Arrangements for erecting wind motors - F05B 2230/61: using auxiliary equipment for lifting or holding - Y02E 10/72: Wind turbines with rotation axis in wind direction - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - B66C: CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES ({specially adapted for lifting invalids A61G7/10;} rope, cable, or chain winding mechanisms, braking or detent devices therefor B66D; specially adapted for nuclear reactors G21) - F03D: WIND MOTORS - F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract The present invention relates to a method for lifting a wind turbine component, such as a rotor blade, gearbox or a rotor, with a lifting yoke comprising a first structural body comprising a crane hook attachment point, a first connection point and a second connection point, a second structural body comprising a third connection point and a fourth connection point, the second structural body further comprising a first axis defined as being parallel to the longitudinal direction of the second structural body, a second axis defined as being perpendicular to the first axis and extending substantially in the transverse direction of the second structural body, said first and second axis defining a lifting plane, and a third axis defined as being perpendicular to the first and second axes. ## Claims ### Claim 1 A wind turbine rotor blade lifting yoke for lifting a wind turbine rotor blade, the lifting yoke comprising: a first structural body comprising a crane hook connection point configured to attach to a hook of a crane, a second structural body located at a distance from the first structural body, a first tensional element connecting a first connection point of the first structural body and a third connection point of the second structural body, a second tensional element connecting a second connection point of the first structural body and a fourth connection point of the second structural body, and wherein a length of the second tensional element is variable, such that an angle between the first and second structural bodies can be changed by changing the length of the second tensional element, an inertial measurement unit positioned on the second structural body, wherein the inertial measurement unit measures the angle of rotation of the second structural body about at least one axis with respect to a horizontal and/or vertical direction, a first sensor, which measures information for calculating the length of the second tensional element, a second sensor for measuring information for calculating an angle of the second tensional element with respect to the second structural body, a control system receiving measurements from the sensors and calculating a center of gravity of the wind turbine rotor blade. ### Claim 2 (depends on 1) The wind turbine rotor blade lifting yoke for lifting a wind turbine rotor blade according to claim 1, wherein the second sensor is a load pin which measures force in the fourth connection point in at least two directions that are not parallel to each other, and wherein the angle of the second tensional element with respect to the second structural body is calculatable by a two force vector provided by the load pin. ### Claim 3 A method for lifting a wind turbine component using a lifting yoke, the lifting yoke comprising: a first structural body comprising a crane hook attachment point, a first connection point and a second connection point, a second structural body comprising a third connection point and a fourth connection point, the second structural body further comprising a first axis defined as being parallel to a longitudinal direction of the second structural body, a second axis defined as being perpendicular to the first axis and extending substantially in a transverse direction of the second structural body, the first axis and second axis defining a lifting plane, and a third axis defined as being perpendicular to the first axis and the second axis, a first tensional element connecting the first connection point and the third connection point, a second tensional element connecting the second connection point and the fourth connection point, wherein a length of the second tensional element is variable, such that an angle between the first and second structural bodies can be changed by changing the length of the second tensional element, and an inertial measurement unit positioned on the second structural body, wherein the method comprises: a) attaching a crane hook to the crane hook attachment point, b) attaching the wind turbine component to the second structural body of the lifting yoke, c) measuring at least one angle of rotation of the lifting plane about at least one of the first and/or second axis with respect to a horizontal plane using the inertial measurement unit, d) determining a distance, along at least one axis in the lifting plane perpendicular to the first and/or second axis about which the angle of rotation of the lifting plane, from the fourth connection point on the second structural body to an intersection between an axis extending vertically through a center of gravity of the wind turbine component and the lifting plane, and e) providing the distance determined, along at least one axis in the lifting plane perpendicular to the first and/or second axis about which the angle of rotation of the lifting plane, from the fourth connection point on the second structural body to the intersection between an axis extending vertically through the center of gravity of the wind turbine component and the lifting plane to a crane operator. ### Claim 4 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the method further comprises: c′) determining a tension in the second tensional element, and c″) comparing information regarding the at least one angle of rotation of the lifting plane and the tension in the second tensional element to a pre-configured look-up table, wherein the pre-configured look-up table contains information regarding the distance, along an axis in the lifting plane perpendicular to the axis about which the angle of rotation of the lifting plane was measured, from the fourth connection point on the second structural body to the intersection between an axis extending vertically through the center of gravity of the wind turbine component and the lifting plane for a plurality of sets of at least one angle of rotation of the lifting plane and tension in the second tensional element. ### Claim 5 (depends on 4) The method for lifting a wind turbine component according to claim 4, wherein the method further comprises: d′) determining the angle between the second tensional element and the first axis of the second structural body, and d″) determining the length of the second tensional element between the second connection point and the fourth connection point, using the angle between the second tensional element and the first axis of the second structural body and the length of the second tensional element between the second connection point and the fourth connection point for determining the distance along the first axis of the second structural body from a point on the lifting yoke to the center of gravity of the wind turbine component. ### Claim 6 (depends on 5) The method for lifting a wind turbine component according to claim 5, wherein determining the angle between the second tensional element and the first axis of the second structural body further comprises: measuring a first force component in the second tensional element, the first force component having a predetermined direction with relation to the lifting plane, measuring a second force component in the second tensional element, the second force component having a predetermined direction with relation to the lifting plane, in which the direction of the second force component is not parallel with the predetermined direction of the first force component, calculating a directional vector from a size of the first and second force components, and calculating the angle between the directional vector and the first axis of the second structural body. ### Claim 7 (depends on 5) The method for lifting a wind turbine component according to claim 5, wherein determining the angle between the second tensional element and the first axis of the second structural body further comprises: measuring the angle of an exit sheave axis of an exit sheave, the exit sheave being connected to the second tensional element in a position between the second connection point and the fourth connection point, wherein the exit sheave is connected to the second structural body and wherein the exit sheave axis is parallel with the second tensional element between the second connection point and the fourth connection point. ### Claim 8 (depends on 5) The method for lifting a wind turbine component according to claim 5, wherein the method further comprises: adding the information about the angle of rotation of the second structural body about at least the second axis and the angle between the second tensional element and the first axis of the second structural body, d″″) determining a horizontal distance from the second connection point of the second structural body to a point on the wind turbine component intersecting with a vertical axis extending from the second connection point of the first structural body, and using the information about the angle of rotation of the second structural body about at least the second axis to determine the distance along at least the first axis of the second structural body from the second connection point of the second structural body to the point on the wind turbine component intersecting with a vertical axis extending from the second connection point of the first structural body. ### Claim 9 (depends on 8) The method lifting a wind turbine component according to claim 8, wherein the method further comprises, during step d): using information about a predetermined horizontal distance from the crane hook attachment point to the second connection point of the first structural body to determine an offset value in the direction along the first axis of the second structural body, adding the offset value to the horizontal distance determined, and using the information about the angle of rotation of the second structural body about at least the second axis to determine the distance along at least the first axis of the second structural body from the second connection point of the second structural body to the point on the wind turbine component intersecting with a vertical axis extending from the second connection point of the first structural body. ### Claim 10 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the method further comprises holding the second structural body in a first position, during steps c) to d), and wherein, after providing information to the crane operator in step e), the method further comprises a step f) wherein the second structural body is moved to a second position, by changing the length of the second tensional element, and lowering or raising the crane hook. ### Claim 11 (depends on 10) The method for lifting a wind turbine component according to claim 10, wherein if the at least one distance provided in step e) is outside a pre-determined range, the second structural body is either repositioned relative to the wind turbine component after step e), or if the at least one distance provided in step e) is within the pre-determined range, then step f) is performed. ### Claim 12 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the method further comprises: using an inertial measurement unit positioned on the second structural body for measuring the angle of rotation of the second structural body about at least one axis with respect to a horizontal and/or vertical direction, using a first sensor to obtain measuring information for calculating the length of the second tensional element, the first sensor being one of an encoder, a positional transducer, or a hall effect sensor system, using a second sensor to obtain measuring information for calculating an angle of the second tensional element with respect to the second structural body, and providing measurements of the sensors to a control system for calculating the center of gravity of the wind turbine component. ### Claim 13 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the wind turbine component is a rotor blade. ### Claim 14 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the wind turbine component is a gearbox. ### Claim 15 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the wind turbine component is a rotor. ### Claim 16 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the first tensional element is a sling. ### Claim 17 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the first tensional element is a wire. ### Claim 18 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the second tensional element is a sling. ### Claim 19 (depends on 3) The method for lifting a wind turbine component according to claim 3, wherein the second tensional element is a wire.