# US 8,465,256 B2 · Wind turbine rotor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,256 B2 - Document ID: US8465256B2 - Status: Granted - Kind: B2 - Application number: 12/529,751 - Filed: 2008-02-15 - Published: 2010-04-08 - Granted: 2013-06-18 - Earliest claimed: 2007-03-14 - Applicants: Vidar Holmoy - Inventors: Vidar Holmoy - Web page: https://patentgrep.com/patent/US8465256B2 ## CPC - F03D 7/0224: {Adjusting blade pitch} - F03D 1/0675: {of the blades} - F05B 2260/96: Preventing, counteracting or reducing vibration or noise - Y02E 10/72: Wind turbines with rotation axis in wind direction - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - 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 Wind power plant rotor comprising one or more rotor blades and stiffening elements to stiffen the rotor, where the rotor blades are arranged such that they can turn around their longitudinal axes relative to corresponding rotor stiffening elements. Each rotor blade may comprise at least two rotor blade parts where the outer rotor blade part may be turnably arranged relative to the inner rotor blade part. The solution facilitates use of longer or slimmer rotor blades while strength and stiffness increase. The fatigue forces are thereby reduced while the corresponding tower structure can be made stiffer and lighter. Manufacturing and transport costs are reduced. Further, the stiffening elements may be formed with an aerodynamic outer cross section as for example a drop profile or wing profile in order to reduce air drag and audible noise. ## Claims ### Claim 1 Wind power plant rotor comprising a rotor shaft; two or more rotor blades attached to said rotor shaft, wherein each rotor blade is comprised of a first radially inward portion and a second radially outward portion; rotor stiffening elements to stiffen the wind power plant rotor; connection devices connecting the rotor stiffening elements with each other and the rotor blades; and blade stiffening elements and a corresponding spacing element associated with each rotor blade and configured to stiffen the associated rotor blade against bending deflections; wherein the rotor stiffening elements and blade stiffening elements are configured to permit rotation of the rotor blades around their longitudinal axes relative to the rotor stiffening elements. wherein said spacing element extends from the associated rotor blade, at a radial location between said first and second portions, and said blade stiffening elements comprise: a first radial blade stiffening element extending from said first portion of the associated rotor blade, to a portion of the spacing element spaced apart from the associated rotor blade; and a second radial blade stiffening element extending from a second portion of the associated rotor blade to a portion of the spacing element spaced apart from the associated rotor blade. ### Claim 2 (depends on 1) Wind power plant rotor according to claim 1, where the rotor stiffening elements comprise rotor shaft struts and/or ring stiffening. ### Claim 3 (depends on 1) Wind power plant rotor according to claim 1, where each rotor blade comprises at least two rotor blade parts with corresponding joining elements. ### Claim 4 (depends on 3) Wind power plant rotor according to claim 3, where the joining elements between the rotor blade parts comprise casings or roller bearings. ### Claim 5 (depends on 3) Wind power plant rotor according to claim 3, where an outer rotor blade part is arranged such that it can turn around its longitudinal axis relative to the corresponding inner rotor blade part. ### Claim 6 (depends on 5) Wind power plant rotor according to claim 5, where the turning of the outer rotor blade part is provided for by a turning mechanism arranged close to the connection between the rotor blade parts. ### Claim 7 (depends on 6) Wind power plant rotor according to claim 6, where the turning mechanism is constituted by an electrically or hydraulically driven mechanism. ### Claim 8 (depends on 3) Wind power plant rotor according to claim 3, where said at least two rotor blade parts are connected by a joining element comprising a tubular connection extending from the one rotor blade part and into the other rotor blade part, where the tubular connection is locked against slip out. ### Claim 9 (depends on 1) Wind power plant rotor according to claim 1, where the connection devices comprise a disk or pipe shaped element which is arranged for lead-through of an adapted part of the corresponding rotor blade, and where said disk or pipe shaped element comprises attachment devices for adjoining rotor stiffening elements. ### Claim 10 (depends on 1) Wind power plant rotor according to claim 1, where the connection devices comprise casings or roller bearings. ### Claim 11 (depends on 1) Wind power plant rotor according to claim 1, comprising one or more stiffening elements which are formed with an aerodynamic outer cross section as for example a drop or wing profile, in order to reduce air drag and audible noise. ### Claim 12 (depends on 1) Wind power plant rotor according to claim 1, where one or more of the stiffening elements are provided with turnbuckles to secure efficient stiffening of the rotor by applying suitable tensioning force to said stiffening elements. ### Claim 13 (depends on 1) Wind power plant rotor according to claim 1, wherein said rotor stiffening elements comprise: a rotor shaft strut extending from the rotor shaft to each of the rotor blades; and ring stiffening elements extending between each pair of adjacently disposed rotor blades.