Patent ID: 12215666

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT

Reference will now be made in detail to exemplary embodiments of the disclosed subject matter, an example of which is illustrated in the accompanying drawings. The method and corresponding steps of the disclosed subject matter will be described in conjunction with the detailed description of the system.

For purpose of explanation and illustration, and not limitation, an exemplary embodiment of the system in accordance with the disclosed subject matter is shown inFIG.113. Similar reference numerals (differentiated by the leading numeral) may be provided among the various views and Figures presented herein to denote functionally corresponding, but not necessarily identical structures.

FIG.1, depicts an exemplary wind turbine, the exemplary wind turbine includes a tower30, a nacelle20, nacelle20disposed at the apex of the tower, and a plurality of rotor blades10operatively coupled to a generator (not shown) housed inside the nacelle. In addition to the generator, the nacelle houses miscellaneous components required for converting wind energy into electrical energy and various components needed to operate, control, and optimize the performance of the wind turbine.

Each rotor blade10is formed as a composite structure with a root portion (for connection to the nacelle) and a tip. The composite root flange is formed from layers (or “plies” or “layups”) of fiber segments that are infused with resin, e.g., vacuum-assisted resin transfer moulding (VARTM). The resin infusion process may comprise arranging a vacuum film over the mold and sealing the vacuum film against a surface, such as a flange of the mold, to define a sealed region encapsulating the layup. A vacuum pump can be employed to remove air from the sealed region. At the same time, resin is admitted into the sealed region. The resin infuses throughout the fibrous layers and between the root insert(s) and the fibrous layers. Each rotor blade may include one or more airfoils along the length of the blade. For example and without limitation, rotor blade10may include one airfoil along the length of the blade. In another example the airfoil may change along the length of the rotor blade10. Each rotor blade10may include airfoils configured to be altered according to the direction of incoming wind and optimization of energy transfer from said wind.

FIG.2depicts an exemplary coupling between the root plate100and the composite resin-infused root flange150, shown in a perspective view of a single mold half (mold omitted for clarity). Root plate100may manufactured from one or more metals and/or one or more alloys thereof. For example and without limitation, root plate100may include one or more steels and their alloys. Root plate100may include carbon steel.

The carbon content of steel is between 0.002% and 2.14% by weight for plain carbon steel (iron-carbon alloys). Too little carbon content leaves (pure) iron quite soft, ductile, and weak. Carbon contents higher than those of steel make a brittle alloy commonly called pig iron. Alloy steel is steel to which other alloying elements have been intentionally added to modify the characteristics of steel. Common alloying elements include: manganese, nickel, chromium, molybdenum, boron, titanium, vanadium, tungsten, cobalt, and niobium. Additional elements, most frequently considered undesirable, are also important in steel: phosphorus, sulfur, silicon, and traces of oxygen, nitrogen, and copper.

Plain carbon-iron alloys with a higher than 2.1% carbon content are known as cast iron. With modern steelmaking techniques such as powder metal forming, it is possible to make very high-carbon (and other alloy material) steels, but such are not common. Cast iron is not malleable even when hot, but it can be formed by casting as it has a lower melting point than steel and good castability properties. Certain compositions of cast iron, while retaining the economies of melting and casting, can be heat treated after casting to make malleable iron or ductile iron objects. Steel is distinguishable from wrought iron which may contain a small amount of carbon but large amounts of slag. Root plate100may include one or more steels including S355.

Root plate100may be configured to secure the root of a molded rotor blade10to a rotor or nacelle. Root plate100may be configured to secure the root of a molded rotor blade10to one or more components of a mold such as mold500or mold halves504and508, which will be discussed at greater length herein below. Root plate100may be constructed from one or more composites itself. Root plate100may be constructed from one or more similar components as rotor blade10as described herein. Root plate100may include one or more apertures disposed therein. For the purposes of this disclosure, “aperture” is an opening in a component. Root plate100may include a plurality of apertures configured in an arc, circular pattern, rectangular pattern, match drilled or cast into the component such as root plate100during the manufacturing process. For example and without limitation, the aperture may include one or more through holes. For example and without limitation, the one or more apertures may include one or more threaded holes, utilizing common or unique threads each, according to one or more thread standards. The apertures may be machined post production or casted, forged, molded, formed, or otherwise manufactured during the making of root plate100. The one or more apertures may include pilot holes for further processing.

Referring now toFIG.3, root plate assembly system may include a rigid metallic plate such as an infused plate110. Infused plate110may be infused partially or fully within a composite component of rotor blade10. Infused plate110may be press fit, co-molded or machined and set into root flange150. Infused plate110may be configured to sandwich the below root flange150along with root plate100. Root plate100and infused plate110may sandwich root flange150and utilize one or more fasteners to clamp together thus securing root flange150.

Root flange150may be one or more composite components disposed at the root of rotor blade10configured support the weight of the finished rotor blade10and resultant forces from wind and rotation as well as serve as a mating component with a rotor. Root flange150may be molded in the molding process of rotor blade150and/or manufactured prior to molding and placed with mold500before rotor blade10is completed. There may be one, two, or more root flanges150disposed within the mold500during the molding process. For example and without limitation, root flange150may be disposed on each of two mold halves and held together in the mold by one or more clamps and hinges. Root flange150may include one or more apertures consistent with the description of apertures herein. The one or more apertures disposed in root flange150may correspond to one or more patterns of apertures disposed in root plate100and/or infused plate110, according to embodiments.

As shown in the rear-perspective view ofFIGS.3-4, a rigid metallic (e.g. steel) plate110can be incorporated into the infused composite root flange150. Thus, the two metallic plates100,110are positioned on opposing sides to “sandwich” the composite root flange150therebetween.

Referring now toFIG.4, the root plate assembly system is shown in rear perspective view showing infused plate110on the viewer-side of root flange150. The hidden mold half (504/508) may be extending normal to plane of the arc made by infused plate110and attached or continuously a part of root flange150. Although not seen inFIG.4, infused plate110may include one or holes, through holes, threaded holes, or other types of apertures that match the one or patterns of apertures disposed in root plate100. The one or more apertures of infused plate110may be match drilled with the apertures of root plate100. The one or more apertures may include threads that match with the threads in the corresponding aperture of root plate100. Any of the root plate100, infused plate110and root flange150may be threaded to accept the same fastener in corresponding apertures. For the purpose of this disclosure, “corresponding apertures” are openings in mating parts that are axially aligned and configured to accept a fastener therethrough.FIG.4depicts a fastening assembly that will be discussed at greater length herein below.

FIG.5depicts a cross-sectional view of an exemplary coupling between the root plate100and the composite root flange (omitted for clarity), with the front root plate100and rear (infused) plate110sandwiching the composite root flange, with all three components releasably coupled together with a fastening assembly. The fastener assembly can include a fastener300which extends through a spacer200, with a distal end of the fastener300received within an aperture in infused plate110(located on the rear side of the composite flange). In the exemplary embodiment shown, the spacer200abuts the rear surface of root plate100, and has a width which is less than the width of the composite flange (omitted for clarity, but occupies the gap inFIG.5—as shown inFIG.9). Root flange150is noticeably absent inFIG.5, as it has not been infused yet. For example and without limitation, the gap between space200, root plate100, infused plate110and traversed by fastener300is filled with infused composite to form root flange150. Therefore the negative space between spacer200, root plate100, infused plate110and fastener300assembly at least partially defines the shape and form of root flange150. It should be noted that in this non-limiting embodiment the fastening assembly ofFIG.5is put in place before the molding of root flange150and therefor rotor blade10is completed, or in embodiments, even started. Therefore fastening assembly may be releaseably and adjustably set into root flange150, and may therefore be adjusted after the molding of rotor blade10, and specifically root flange150.

Referring now toFIGS.6and7, a composite root flange150can be formed utilizing Vacuum Assisted Resin Transfer with infused plate110infused on the rear surface thereof. The root plate100is then positioned adjacent the front surface of root flange150, with corresponding apertures101,111provided for alignment. Corresponding apertures may be utilized only for alignment, or for alignment and securing of root plate110to root flange150and further to infused plate110or additionally may be used only for securing root plate100, root flange150and infused plate110.

Referring now toFIG.8, a cross sectional view of an exemplary root plate100and root flange150connection, with an axially extending fastener (e.g. M20 bolt) and collar for relative axial adjustment. The connection may include root plate100disposed on the left hand side of the Figure. Root plate100includes a through hole wherein threaded collar250is disposed at least partially therethrough. Threaded collar250may include a first set of threads disposed on the outer cylindrical surface of threaded collar250. The exterior threads of threaded collar250may be configured to mate with the threads of an interior cylindrical surface of aperture101, for example and without limitation. Threaded collar250may be configured to be rotated along said threads and move axially within aperture101, that is to say, by turning the threaded collar250, the threaded collar250would move axially in or out of aperture101, or any opening theredisposed. Threaded collar250includes an interior opening including a second set of threads thereon. The second set of threads may be configured to mate and secure one or more fasteners such as fastener300therein. Fastener300may include an M20 stud bolt. Threaded collar250may include one or more lubricants configured to ease the turning of the threaded collar250within root plate100and/or fastener300within threaded collar250. Threaded collar may be fixed to infused plate110according to embodiments. Threaded collar250may be fixed to root plate100, according to embodiments. Threaded collar250may be fixed to root flange150, according to embodiments.

With continued reference toFIG.8, the connection assembly includes sealing collar401and at least one sealing washer402. Sealing collar401may be configured to prevent infused composite from reaching the interior of the fastening assembly and coating the one or more threads found therein. Sealing collar401may be put in place prior to the infusion of composite as described above. The connection assembly includes at least one washer such as sealing washer402. Sealing washer402or the plurality thereof may be configured to seal the circumference of threaded collar250from infused composite. That is to say that the seal may be configured for liquid-tightness at the viscosities the infused composite or resin used therein. The at least one washer such as sealing washer402may be configured to correspond to the type of liquid or semi-liquid materials such as resin used in the manufacture of the rotor blade10. Connection assembly ofFIG.8includes locknut202and axial lock bolts212. Locknut202may include threads disposed on the outer cylindrical surface configured to mate the interior surface threads of aperture101or others. Locknut202may be configured to arrest the axial motion of threaded collar250and therefore fastener300. Locknut2020may be included to abut the flat surface of threaded collar250disposed orthogonal to the axial direction of movement. Locknut may be configured to be fixed to said threaded collar250by one or more axial lock bolts212. Axial lock bolts212may be threaded for a portion thereof of along its entire shaft length. Axial lock bolt212may be configured to pass through a non-threaded through hole in locknut202and be threaded into one or more holes in the flat surface of threaded collar250. For example and without limitation the axial lock bolts212may be threaded along its entire shaft portion and be threaded through the locknut202and threaded collar250. Connection assembly ofFIG.8may include bolt cover203configured to close the opening wherein the fastener300, threaded collar250, locknut202and axial lock bolts212are disposed within. Bolt cover203may be one or more sheets of metal, composite, plastic or rubber configured to be coupled to root plate100and cover the opening left by the fastening assembly.

Referring now toFIG.9, the connection assembly ofFIG.8is shown in cross-sectional view. Root flange150can be seen in between infused plate110and root plate100(no reference character shown). Root flange150can be seen extending rightwards past infused plate110interior to infused plate110.

Referring now to the exploded and enlarged view ofFIGS.10-11, threaded collar250is provided that engages root plate100of the mold, extends through root flange150, and into the rear infused plate110, an exemplary embodiment of which is shown in cross-sectional view inFIGS.8and9. Threaded collar250can be, fixedly (e.g. welded or glued) or releasably, bound to the infused plate110within the mold's flange by a socket head cap screw—the threaded collar assembly allowing for relative adjustment of the root flange and root plate (e.g. axially or spanwise displacement).

In operation, turning of threaded collar250generates an axial movement. For example and without limitation, clockwise turning generates axial or spanwise displacement towards the root plate100, or from left-to-right as shown inFIGS.8-9. This movement effectively adjusts root plate100with respect to root flange150of the wind turbine mold. Once the desired orientation (e.g. depth of insertion and axial alignment) is achieved, the adjustable threaded collar250is locked in position with a lock nut202that can be engaged through a one or plurality of axial lock bolts212, which can then be covered by bolt cover203to prevent undesired loosening of bolts212. Accordingly, the locked position of threaded collar250, and therefore the orientation of root plate100remains fixed in a desired orientation within the mold, the desired orientation being without any undesired deviation or alterations. Threaded collar250can include an internal channel that has a first portion with a threaded internal surface to mesh with the threads of the fastener300. A second portion of the internal channel of collar250can be sized to receive the head of the fastener300such as a counter bore or countersink. Also, threaded collar250is sized with a first diameter “D” (e.g. which receives the head portion of the fasteners300) and a smaller diameter “d” (e.g. which receives the threaded portion of the fasteners300).

A sealing collar401is provided which circumscribes the fastener300and threaded collar250, with the sealing collar401extending laterally outward from the exterior surface of the root flange150. The sealing collar401extends a distance outward beyond the location of the sealing washers402, and terminates at a location that coincides with the top of the threaded portion of the fastener300(e.g. the location where the head portion of the fastener300is located). In some embodiments, the sealing collar401can deform to create a seal with the inner diameter of the apertures within the root flange150. For example, the sealing collar401form radially expanding bellows as the axial/spanwise portion is compressed.

In some embodiments a spherical washer404can be incorporated into the assembly, as shown in the cross-sectional view ofFIG.9. The spherical washer404can be positioned (axially) between the threaded collar250and the root flange150. Spherical washers, also known as Self-Aligning Washers or Equalizing Washers, may be configured for fastening applications on an uneven surface. The washer set consists of a “top” half that is convex and a “bottom” half that is concave. The top washer has a slightly narrower inner diameter than the bottom washer while both have the same radius. This enables a bolt or screw to pass through both washers and “self-align” allowing for a flat clamping washer surface. The spherical washer sets are designed for a 3-4 degree angle of correction. Also, the spherical washer404can be sized with an outer diameter less than the outer diameter of the threaded collar250(as well as less than the inner diameter of the sealing collar401and sealing washers402). Sealing and/or cushioning washers create an airtight/watertight/liquid tight seal between fasteners and surfaces. Also known as rubber washers or sealing washers, they prevent leakage around plumbing fixtures, brake systems, hydraulic applications, resin molds, or the like. The distal end of the threaded collar can include a conical (and optionally un-threaded) portion that projects into the aperture of the spherical washer404, as shown inFIG.9. The outer diameter of the threaded collar230can likewise be sized so as to be concentrically received by the sealing collar401and sealing washers402.

FIG.10shows an exploded view of the various components shown inFIG.8. The root flange150includes an aperture that receives sealing collar401therein. A plurality (e.g. three) sealing washers402are positioned in adjacent to and in contact with the root flange150, and sized with a diameter greater than the aperture containing the sealing collar401therein. This prevents the sealing washers402from being positioned within the aperture, and occluding or interfering with the insertion of the sealing collar401. The washers402are similarly positioned adjacent to and in contact with the root plate100on the opposing side.

The (externally) threaded collar250is inserted within a complimentarily threaded aperture in the root plate100, with a distal/bottom end of the collar250passing through the washers402and into the sealing collar401within the aperture of the composite flange150. The presence of the sealing washers402and sealing collar401prohibit resin from reaching the adjustment mechanism of the collar250and fastener300interaction. Also, the present disclosure allows for all axial adjustments to be performed form outside of the mold through the removal of sealed access covers, and without removal of the complete root plate assembly.

The fastener300has external threads that, when inserted through and beyond the bore/channel of the collar250, engage the complimentary threads on the interior surface of the infused root plate110. As the fastener300is turned the threaded engagement with the infused plate110draws the fastener further into the infused plate110, with the portion of the fastener300disposed within the threaded collar250having an interference, or friction fit, engagement; thus the threads of fastener300only establish a threaded coupling with the complimentary threads of the infused root plate110. A locking nut202is then applied on top of the fastener to inhibit or prohibit relative movement (e.g. loosening/retraction) between the threaded collar250and the root plate100. Furthermore, the locking nut202is itself retained in a locked position with a plurality (e.g. four equidistantly spaced) screws212which extend from the top of the locknut202, beyond the head of the fastener300, and are received within apertures formed in the sidewall of the collar250, as shown inFIG.6. Next, a bolt covering plate203is attached to the upper/outer surface of the root plate100, with the bold covering plate spaced from the outer/upper surface of the locknut202and screws212. Thus, the covering plate203encloses threaded collar250, and is retained in locked position via screws214.

For purpose of illustration and not limitation, the fastener300can be formed as a bolt having threads configured to mesh with threads formed on the interior surface of the infused root plate110. As described above, the fastener300is sized with an outer diameter proximate the head, that is sufficient to establish an interference fit within the threaded collar250. In some embodiments, the fastener may be configured as a M20-M50 threaded stud bolt. Other lengths may also be possible and the invention is not limited to the range above. The exemplary views presented herein focus on a single fastening assembly for clarity, but a plurality of fastening assemblies can be incorporated and distributed about the circumference of the root plate/flange. For example, the fastening assemblies can be equidistantly spaced from each other.

Referring now toFIG.12A, a mold500is shown in perspective view. It can be seen fromFIG.12Athat mold500includes a first mold half504and a second mold half508configured to be clamped together creating a void between the two halves, the void defining the outer mold line of rotor blade10. Root plate100can be seen as two halves joined to create a circular root plate, each half of root plate100associated with mold half504and mold half508. Mold500may include one or more clamps that can be seen where the two mold halves meet and create a seal between the two halves. The clamps may be regularly spaced or spaced at strategic points where more or less pressure is required to seal the mold halves504,508. One mold half may be designed to be a pressure side of a vacuum assisted resin transfer process mold and one mold half may be designed to be the vacuum side of a VART process. Mold500may include one or more hinges and/or linkages configured to maneuver and support mold500during the opening and closing process. The mold500may be opened and/or closed automatedly by one or more actuators or by hand. The hinges and/or linkages may be additionally capable of assisting in the clamping of mold500. High-rate production tools, such as mold500, for example, may be made of robust metals that can stand up to repeated cycles and maintain good surface finish and dimensional accuracy. Mold500may be configured to produce rotor blade10, which are high-performance composite parts that can be formed can be made from carbon fiber/epoxy, monolithic graphite, castable graphite, ceramics or metals (typically aluminum, steel and alloys of the same). According to embodiments, each material offers unique capabilities and drawbacks.

Referring now toFIGS.12B and12C, mold haves504,508are shown in perspective views. The mold half504may be configured to define one half of a rotor blade10. The mold half504may be the top or bottom half of one or more airfoils along the length of rotor blade10relative to the chord of the airfoil. Mold halves504,508may be configured to be supported by one or more struts, support members or super structure to support the shape of mold500before and during the subjection of the interior of the mold to a vacuum.

Referring now toFIG.13, a method for adjustable coupling of a root plate assembly is presented in flow diagram form. Method1300includes, at step1305, providing a root plate such as root plate100. Root plate100may be any root plate as described herein. Root plate100may be configured to support and attach to the root portion of a mold such as mold500, specifically mold half504and/or508. Root plate100may be include one or more apertures such as aperture101/111as described herein comprising one or more patterns.

Still referring toFIG.13, method1300includes, at step1310, providing a threaded collar such as threaded collar250. Threaded collar250including a longitudinally extending channel therethrough, the channel axially and concentrically aligned with at least one aperture. Threaded collar250includes threads disposed on the external cylindrical surface configured to mesh with threads disposed on the interior cylindrical surface of the aperture in which threaded collar250is disposed. Threaded collar250may be configured to rotate through the threads thereby axially adjusting the position of threaded collar250in the aperture. Threaded collar250includes threads disposed on the internal cylindrical surface of threaded collar250configured to mesh with a fastener such as fastener300.

Still referring toFIG.13, method1300includes, at step1315, providing an infused plate such as infused plate110. Infused plate110may be any infused plate as described herein. Infused plate110may be machined into a root flange150, root flange150may be any root flange as described herein. Infused plate110may include openings, holes apertures corresponding to the apertures disposed in root plate100. Infused plate110may be partially or fully infused into root flange150by adhesives, fasteners, or a combination thereof.

Still referring toFIG.13, method1300includes, at step1320, providing a fastener disposed through the threaded collar's longitudinally extending channel. The fastener may be fastener300or any suitable fastener. Fastener300includes threads disposed on at least a portion of the fastener configured to mesh with the internal threads of threaded collar250. Fastener300may be partially seated with threaded collar250, at least partially seated within root plate100, and at least partially through infused plate110.

Still referring toFIG.13, method1300includes, at step1325, providing infused composite to form the root flange such as root flange150. Infused composite may, in embodiments be present before the fastening of the assembly as described hereinabove. Infused composite may be applied after the fastening of the aforementioned components. Root flange150may be a continuous component with the each of the mold halves504/508. Root flange150may be coupled to another or a plurality of components of one or more mold halves504/508. Although not shown inFIG.13, the components may be sealed from the infused composite and/or the resin from the molding process by one or more sealing components such as sealing collar and at least one washer such as sealing washer as described herein. Fastener300may be partially threaded through root plate100, root flange150and infused plate110, or a portion thereof. The fastener300is partially disposed through threaded collar250disposed in root plate100.

Still referring toFIG.13, method1300includes, at step1330, adjusting the threaded collar250. Threaded collar250is adjusted by turning the threaded collar250along the threads of root plate100, thereby axially moving threaded collar250up or down in the aperture it's disposed in. Threaded collar250is adjusted and thereby adjusts the threaded portion of the fastener in the above mentioned components.

Still referring toFIG.13, method1300includes, at step1335, adjustably coupling the root plate to the infused plate. The root plate may be root plate100and the infused plate may be infused plate110. The distance between root plate100and infused plate110and therefore the distance between root flange150and root plate100is variable according to the position of threaded collar250and fastener300.

Thus, the present disclosure provides a structural configuration, and method, for adjustment of the root plate relative to the root flange of the blade mold that is facilitated by threaded components, and avoids the need for complex custom-fit washers, etc., that must be sized at the assembly stage. While the present disclosure primarily provides for axial adjustment of the root plate and root flange, some lateral/vertical adjustment can also be performed by operation of the fastening system (e.g. inserting/withdrawing the bolt300within the collar250). The techniques disclosed herein can be used on all root plates affixed to composite molds with semi-permanent intent. Modifications can be performed in the case of a frequently removed root plate (as driven by process needs) whereas adjustment components can move to the interfacing mold frame, as opposed to inside of the plate, in some embodiments.

While the disclosed subject matter is described herein in terms of certain preferred embodiments, those skilled in the art will recognize that various modifications and improvements may be made to the disclosed subject matter without departing from the scope thereof. Moreover, although individual features of one embodiment of the disclosed subject matter may be discussed herein or shown in the drawings of the one embodiment and not in other embodiments, it should be apparent that individual features of one embodiment may be combined with one or more features of another embodiment or features from a plurality of embodiments.

In addition to the specific embodiments claimed below, the disclosed subject matter is also directed to other embodiments having any other possible combination of the dependent features claimed below and those disclosed above. As such, the particular features presented in the dependent claims and disclosed above can be combined with each other in other manners within the scope of the disclosed subject matter such that the disclosed subject matter should be recognized as also specifically directed to other embodiments having any other possible combinations. Thus, the foregoing description of specific embodiments of the disclosed subject matter has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosed subject matter to those embodiments disclosed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the method and system of the disclosed subject matter without departing from the spirit or scope of the disclosed subject matter. Thus, it is intended that the disclosed subject matter include modifications and variations that are within the scope of the appended claims and their equivalents.