Load guide for wind turbine

Abstract

A lifting system for lifting a wind turbine component includes: a first lifting device situated in a nacelle of the wind turbine, the first lifting device connectable by a first lifting line to the wind turbine component for lifting and lowering the wind turbine component; a second lifting device; and, a load guide connected to the second lifting device by a second lifting line to be liftable and lowerable by the second lifting device. The load guide includes: a rigid ring that extends at least partially around a perimeter of a tower of the wind turbine; a plurality of rollers mounted on the ring, each of the plurality of rollers configured to rollingly contact the tower and roll on the tower as the load guide moves vertically along the tower; and, one or more load connectors configured to receive and support the wind turbine component on the load guide.

Description

[0001] LOAD GUIDE FOR WIND TURBINE

[0002] Cross-reference to Related Applications

[0003] This application claims the benefit of USSN 63 / 637,176 filed April 22, 2024, the entire contents of which is herein incorporated by reference.

[0004] Field

[0005] This application relates to wind turbines, in particular to load guides to assist with lifting a load up to the top of a wind turbine.

[0006] Background

[0007] Lifting wind turbine components up and down from the top of a tower of a wind turbine remains a difficult task, a task which is generally accomplished using lifting devices (up-tower and / or ground-based) such as cranes, winches and the like. The task is particularly difficult under conditions of high-wind and / or when the wind turbine is mounted on a fixed or floating off-shore platform, which can cause the wind turbine and a lifted load to sway. Under such conditions, a load suspended by a lifting line connected to a lifting device tends to sway relative to the tower while the load is being raised or lowered. Swaying of the load can result in the load crashing into the tower, which could be catastrophic for either or both the load and the tower.

[0008] There remains a need for a lifting system for lifting a wind turbine component, especially for a fixed or floating offshore wind turbine, where the lifting system controls the sway of the lifted component to minimize the chance that the component will contact the tower during a lifting process.

[0009] Summary

[0010] Described herein is a lifting system for lifting a wind turbine component of a wind turbine, the lifting system comprising: a first lifting device situated in a nacelle of the wind turbine, the first lifting device connectable by a first lifting line to the wind turbine component for raising and lowering the wind turbine component; a second lifting device; and, a load guide connected to the second lifting device by a second lifting line to be raisable and lowerable by the second lifting device, the load guide comprising: a rigid ring that extends at least partially around a perimeter of a tower of the wind turbine; a plurality of rollers mounted on the ring, each of the plurality of rollers configured to rollingly contact the tower and roll on the tower as the load guide moves vertically along the tower; and, one or more load connectors configured to receive and support the wind turbine component on the load guide.

[0011] Also described herein is a load guide for assisting with lifting and lowering a wind turbine component to and from a nacelle of a wind turbine, the load guide comprising: a rigid ring extendable at least partially around a perimeter of a tower of the wind turbine; a plurality of inwardly oriented rollers mounted on the ring, the rollers spaced-apart around the ring and configured to roll on the tower as the load guide moves vertically along the tower; a lug configured to be connected to a lifting line; and, one or more outwardly oriented load connectors configured to securely attach the wind turbine component thereto, the one or more outwardly-oriented load connectors positioned so that lifting of the load guide causes the ring to tilt thereby engaging the plurality of rollers in contact with the tower.

[0012] Also described herein is a method of raising or lowering of a wind turbine component to or from a nacelle of a wind turbine, the method comprising: connecting the wind turbine component to a load guide, the load guide comprising: a rigid ring extending at least partially around a perimeter of a tower of the wind turbine; and, a plurality of inwardly oriented rollers mounted on the ring, the rollers spaced-apart around the ring and configured to roll on the tower as the load guide moves vertically along the tower; raising or lowering the wind turbine component with a first lifting device and raising or lowering the load guide with a second lifting device, whereby the second lifting device is connected to the load guide at a lifting point so that the inwardly oriented rollers are in contact with the tower during the raising or lowering of the load guide and the wind turbine component and the load guide are lifted or lowered at a same speed while all the inwardly oriented rollers are in contact with the tower.

[0013] In some embodiments, the method comprises using the lifting system described above. In some embodiments, the method comprises using the load guide as described above.

[0014] The load guide is a control device to help prevent a load suspended from a lifting device from contacting a wind turbine tower while the load is being lifted by the lifting device. The load guide comprises a ring that wraps entirely around or partially around the tower, the ring keeping the suspended load from contacting the tower. The ring may be raised (or lowered) independently of but at the same rate as the raising (or lowering) of the suspended load so that the ring remains between the load and the tower while the ring and load are lifted or lowered together. The ring may be connected to the load to help stabilize the load while, if desired or required, the ring is stabilized against the tower. The lifting system can be adapted to be used in conjunction with any wind turbine for which turbine components must be lifted up and down the tower. The lifting system is particularly useful for use with wind turbines located in areas of high wind and / or with floating offshore wind turbines.

[0015] The lifting system comprises a first lifting device and a second lifting device. The first lifting device is connected to the wind turbine component to be lifted while the second lifting device is connected to the load guide. Some examples of lifting devices that are useful as the first and second lifting devices include cranes, winches and the like. Various suitable lifting devices are known. The first lifting device can be situated in the nacelle of the wind turbine and is preferably a nacelle-mounted crane. The second lifting device can be situated up-tower, down tower, mid-tower and can be located on the tower or remote from the tower. In some embodiments, the second lifting device comprises a winch. In some embodiments, the second lifting device is situated down-tower near the base of the tower but remote from the tower, for example on a platform apart from the tower. The first and second lifting devices comprise respective lifting lines, which are adapted to be connected to the load and the load guide, respectively. The first lifting device operates to lift the load while the second lifting device operates to lift the load guide. The load and the load guide may be lifted at the same or different circumferential locations around the perimeter of the tower. In some embodiments, the load and the load guide are lifted on the same side of the tower. In some embodiments, the load and the load guide are lifted on opposite sides of the tower.

[0016] In some embodiments, the lifting system further comprises an anchor arm mounted in the nacelle. In some embodiments, the anchor arm comprises a sheave around which the second lifting line is reeved so that the second lifting line extends from the second lifting device up to the anchor arm and from the anchor arm down to the load guide. In some embodiments, the anchor arm comprises a vertically oriented strut mounted in the nacelle and a horizontally oriented strut extending from the vertically oriented strut outward over an upper edge of the nacelle. In some embodiments, the sheave is situated at or proximate a distal end of the horizontally oriented strut. The anchor arm facilitates the ability to locate the second lifting device in a variety of locations while allowing a portion of the second lifting line to be always vertically oriented between the nacelle and the ring of the load guide.

[0017] The load comprises the wind turbine component. In some embodiments, the wind turbine component is a component that normally operates in the nacelle. Some examples of wind turbine components are gearboxes, generators and the like. In some embodiments, the load also comprises a lifting frame. The lifting frame is configured to support the wind turbine component during a lifting operation. In some embodiments, the lifting frame comprises frame elements that support the wind turbine component. The turbine component can be attached to the lifting frame by one or more fasteners or the turbine component can rest on frame elements without being attached to the lifting frame by fasteners. In some embodiments, the lifting frame is configured to be securely attachable to the wind turbine component. In some embodiments, the lifting frame is connected by the first lifting line to the first lifting device. In some embodiments, the lifting frame comprises connection elements to which the first lifting line can be connected.

[0018] The load guide comprises a rigid ring (i.e., a load control ring). The ring extends at least partially around a perimeter of a tower of the wind turbine. The ring has a diameter that is large enough for the ring to entirely encircle or at least partially encircle the wind turbine tower near a base of the tower and at a top of the tower while providing a tolerance (i.e., a gap) between the tower and the ring to accommodate the presence of the plurality of rollers mounted on the ring. The ring is rigid enough not to unduly deform and lose shape during a lifting operation.

[0019] In some embodiments, the second lifting line is connected to the ring of the load guide. In some embodiments, the ring is connected to the second lifting line at a position on the ring so that lifting the ring causes the ring to tilt thereby engaging all the rollers of the plurality of rollers of the load guide with the tower. In some embodiments, the load guide comprises a lug configured to be connected to a lifting line, in particular to the second lifting line. In some embodiments, the lug is situated on the ring. In some embodiments, the ring comprises a segment that is openable to permit installing the ring around the tower proximate a base of the tower. In some embodiments, the openable ring segment is hinged at one end so that the ring segment can be rotatably connected to the remainder of the ring, whereby rotation of the ring segment at the hinge opens and closes the ring. Other ways of making the ring openable to permit installing the ring around the tower may be utilized. The ring may be any desired shape. In some embodiments, the ring is a circle, an oval, a polygon (regular or irregular), or a shape with a combination of straight and curved edges that permits the ring to extend around the perimeter of the tower. Some examples of polygons are multi-sided polygons such as triangles, four-sided polygons (e.g., squares, rectangles), pentagons, hexagons and the like.

[0020] The load guide further comprises a plurality of rollers mounted on the ring. The plurality of rollers is in rolling contact with the tower and roll on the tower as the load guide moves vertically along the tower. The plurality of rollers may comprise 2, 3, 4, 5, 6 or more rollers. The number of rollers required or desired depends to some extent on the shape of the ring. Whatever the shape of the ring, the plurality of rollers is distributed around the ring to ensure that the ring does not contact the tower during a lifting operation. In some embodiments, the plurality of rollers comprises one or more rollers at the side of the ring where the load is located and one or more rollers at the opposite side of the ring from where the load is located. In some embodiments, the plurality of rollers comprises at least three rollers spaced around of the ring. In some embodiments, the plurality of inwardly oriented rollers comprises two opposed sets of two rollers. The plurality of rollers is configured to prevent the load guide from becoming stuck while the load guide moves vertically along the tower. The plurality of rollers may be oriented inwardly from the ring toward the tower to facilitate contact with the tower. In some embodiments, one or more of the plurality of rollers is resiliently mounted on the ring to provide a cushioning effect between the rollers and the tower. In some embodiments, resilient mounting may be accomplished with springs (e.g., mechanical, pneumatic and the like), for example pneumatic cylinders, compression springs, leaf springs and the like.

[0021] The load guide further comprises one or more load connectors configured to receive and support the wind turbine component on the load guide. In some embodiments, one or more load connectors are outwardly oriented from the load guide and are configured to securely attach the wind turbine component thereto, either directly, through the lifting frame or through a yoke as described below. In some embodiments, the one or more outwardly- oriented load connectors are positioned so that lifting of the load guide causes the ring to tilt thereby causing the plurality of rollers to engage with the tower. In some embodiments, the one or more load connectors comprises two spaced-apart load connectors. In some embodiments, the second lifting line is connected to the load guide at a position between the two spaced-apart load connectors. In some embodiments, the lug of the load guide is positioned between the two spaced-apart load connectors. In some embodiments, the one or more load connectors comprises one or more connecting lines, one or more receiving brackets, one or more connecting arms or any combination thereof. In some embodiments, the one or more load connectors comprises one or more connecting lines or end portions thereof. In some embodiments, the one or more load connectors comprises two or more connecting lines or end portions thereof. In some embodiments, the one or more load connectors comprises two spaced-apart receiving brackets oriented outwardly from the ring.

[0022] In some embodiments, the load guide further comprises sheaves and / or line guides configured to guide the connecting lines along the ring. In some embodiments, the connecting lines are guided by the sheaves and / or line guides from a rear of the ring to a front of the ring. In some embodiments, the load guide comprises one or more control devices (e.g., winches, cranes, come-alongs or the like) connected to the connecting lines for operating the connecting lines. In some embodiments, the connecting lines are connected to one or both of the lifting frame and the yoke for adjusting lateral position of the lifting frame and / or the yoke relative to a vertical axis of the tower. The one or more control devices operate to maintain tension on the one or more connecting lines while the load and the load guide are being lifted, thereby stabilizing the load guide relative to the load, and, if desired or required, stabilizing the load guide relative to the tower. The one or more control devices may be situated in any suitable location. In some embodiments, the one or more control devices are situated downtower and the one or more connecting lines extend upward from the one or more control devices to a rear of the ring of the load guide where the one or more connecting lines are reeved through the sheaves and line guides on the ring and then pass along the ring to the front of the ring to the load where the one or more connecting lines are connected to the load (or the yoke). In some embodiments, the one or more connecting lines are connected to the lifting frame either directly or through the yoke, thereby connecting the load to the ring.

[0023] In some embodiments, the lifting system further comprises a yoke connected to the lifting frame. In some embodiments, the yoke is rigidly but removably secured to the lifting frame. In some embodiments, the yoke is integral with the lifting frame and is therefore not removably secured to the lifting frame. In some embodiments, the yoke is configured to be received and supported by the one or more load connectors of the load guide. In some embodiments, the yoke comprises opposed spaced-apart multi-armed support elements connected by a crossbar. In some embodiments, first ends of the support elements are configured to be connected to the load guide. In some embodiments, second ends of the support elements are secured to the lifting frame. In some embodiment, the second ends of the support elements are configured to be rigidly but removably secured to the lifting frame.

[0024] In some embodiments, the yoke comprises two parallel multi-armed support elements connected by a crossbar. In some embodiments, each support element comprises a central bar and three end arms at a distal end of the central bar. In some embodiments, the end arms point toward the tower when the yoke is in use. In some embodiments, the central bar is releasably secured to the load, for example to the lifting frame, proximate a proximal end of the central bar. In some embodiments, the end arms comprise a first end arm parallel to the central bar and two obliquely oriented end arms. In some embodiments, the two obliquely oriented end arms form an angle between each other defining a space in which the first end arm extends. In some embodiment, one of the obliquely oriented end arms is an upper end arm and the other obliquely oriented end arm is a lower end arm. In some embodiments, the first end arm is a middle end arm and comprises a connector to which one of the one or more load connectors is connectable. In some embodiments, the connector comprises a flange, an aperture, a bracket, a tie-down or the like depending on the type of load connector. In some embodiment, one or more of the connecting lines run from the one or more control devices to the first end arms of the yoke thereby connecting the one or more connecting lines to the lifting frame connected to the yoke. The one or more connecting lines are operable by the one or more control devices to adjust the lateral position of the lifting frame and / or the yoke relative to a vertical axis of the tower to prevent swaying of the load during the lifting process. In some embodiments, the first end arms of the support elements comprise flanges that are configured to engage with receiving brackets of the ring so that the yoke is further supported on the ring. The load guide, yoke and lifting frame are therefore all effectively connected together during a lifting process so that motion of the floating offshore platform and / or winds do not unduly affect the lifting process.

[0025] In some embodiments, the yoke comprises a plurality of rolling elements. In some embodiments, the obliquely oriented end arms each comprise one or more of the plurality of rolling elements. In some embodiments, the obliquely oriented arms are oriented so that the rolling elements engage tracks of a vertical guide frame when the yoke engages the vertical guide frame, as described below.

[0026] In some embodiments, the lifting system further comprises a vertical guide frame supported over an upper edge of the nacelle. In some embodiments, the vertical guide frame is installed on a service crane gantry at the bottom of the nacelle inside the nacelle. In some embodiments, the vertical guide frame is U-shaped and hook over the upper edge of the nacelle. In some embodiments, the vertical guide frame extends downward from the upper edge of the nacelle along an outside of the nacelle. In some embodiments, the vertical guide frame comprises tracks in which the plurality of rolling elements of the yoke rolls when the yoke is engaged with the vertical guide frame. In some embodiments, the vertical guide frame comprises spaced-apart arcuate rails that hook over the upper edge of the nacelle. In some embodiments, the arcuate rails comprise the tracks for engaging the rolling elements of the yoke. The vertical guide frame serves to guide the yoke and therefore the load alongside the nacelle while securing the load from swaying and contacting the nacelle. The yoke essentially flips over as the yoke follows the tracks over and into the nacelle, thereby putting the lifting frame inside the nacelle.

[0027] In some embodiments, one or more sensors may be installed to determine lift speed and / or speed changes of the load and / or load guide, positions and / or position changes of the load and / or load guide, wind speed, or any other useful parameter. In some embodiments, the one or more sensors comprises one or more strain gauges, limit switches, optical sensors (e.g., cameras) and the like. In a lifting method, of the wind turbine component to or from the nacelle of the wind turbine, the wind turbine component is connected to the load guide, directly or through the lifting frame and / or the yoke. The load and the load guide are lifted by independent lifting devices. However, the lifting speeds of the first lifting device and the second lifting device are matched to ensure that the load and the load guide are lifted in tandem while the load is being lifted. In some embodiments, the first and second lifting devices are controlled by a control system. In some embodiments, the control system is a master / slave control system in which the second lifting device is a slave to the first lifting device. In the master / slave control system, the speed of the second lifting device is continuously synchronized to the speed of the first lifting device to continuously ensure that the load guide moves at the speed as the load. Lifting the load and the load guide vertically at the same speed helps avoid lifting the load guide with the first lifting device thereby lifting the load guide through the load, including the wind turbine component. Lifting the load and the load guide vertically at the same speed also helps prevent the load, including the wind turbine component, from being situated above or below the load guide instead of next to the load guide.

[0028] The plurality of inwardly oriented rollers mounted on the ring are spaced-apart around the ring and configured to roll on the tower as the load guide moves vertically along the tower. The second lifting device is connected to the load guide at a lifting point on the load guide so that the inwardly oriented rollers are in contact with the tower. Contact of the rollers with the tower is generally maintained by gravity because the lifting point is not over the center of gravity of the load guide. The load guide, having sufficient mass and suspended from such an asymmetric lifting point, therefore tilts during the lifting process ensuring that the rollers remain in contact with the tower. Because the diameter of the tower might change as a function of height, tilting of the load guide during the lifting process maintains contact of the rollers with the tower. In some embodiments, the lifting point on the load guide is at the front of the load guide where the load is situated. In some embodiments, the lifting point of the load guide is at the rear of the load guide, opposite to where the load is situated. However, during the lifting process, one or more of the inwardly oriented rollers on the load guide might lose contact with the tower despite the action of gravity. In response to one or more of the rollers losing contact with the tower despite the action of gravity, the load guide may be tilted to maintain contact of all the rollers with the tower by: using the second lifting device connected at a front of the load guide to change the speed of the load guide; and / or, operating the one or more connecting lines operatively connected at a rear of the load guide.

[0029] In some embodiments of the method, when the load guide and the load reach a bottom of the nacelle, the yoke engages the vertical guide frame. In some embodiments, the tracks are situated in outer faces of the arcuate rails and continue through vertical and non-vertical portions of the arcuate rails. Once the rolling elements of the yoke are engaged on the tracks of the vertical guide frame, the yoke disconnects from the load guide as the load is raised further by the first lifting device. As the load is raised alongside the nacelle, the rolling elements roll in the tracks, the tracks keeping the load moving in a straight line until the yoke and the load reach a top of the vertical guide frame and are higherthan the upper edge of the nacelle. In some embodiments, continued motion of the yoke on the vertical guide frame causes the yoke to be released from the lifting frame so that the lifting frame is independent of the yoke. In some embodiments, the yoke is supported on the nacelle by the vertical guide frame when the yoke and the load are separated. In some embodiments, the lifting frame is positioned over top a destination for the wind turbine component and lowered to place the wind turbine component in position, and the lifting frame is detached from the wind turbine component.

[0030] In some embodiments, the method further comprises supporting the wind turbine component on a lifting frame for the wind turbine component, attaching a yoke to the lifting frame, supporting the yoke on the load guide, lifting the load guide and the lifting frame with the wind turbine component attached thereto up to the nacelle, detaching the yoke from the load guide by lifting the lifting frame along with the wind turbine component and the yoke away from the load guide using the first lifting device, engaging the yoke with a track on an arcuate rail hooked over an upper edge of the nacelle, lifting the lifting frame along with the wind turbine component and the yoke using the first lifting device to move the yoke along the track overtop of the upper edge of the nacelle until the wind turbine component is inside the nacelle, lowering the lifting frame along with the wind turbine component into the nacelle using the first lifting device, and removing the wind turbine component from the lifting frame. In some embodiments, the lifting frame is detached from the yoke once the yoke is inside the nacelle.

[0031] In some embodiments, the method further comprises supporting the wind turbine component on a lifting frame for the wind turbine component inside the nacelle of the wind turbine, lifting the lifting frame along with the wind turbine component using the first lifting device, lifting the lifting frame along with the wind turbine component and a yoke attached to the lifting frame using the first lifting device to move the yoke along a track of an arcuate rail hooked over an upper edge of the nacelle such that the lifting frame with the wind turbine component therein and the yoke are lifted over top of the upper edge of the nacelle until the wind turbine component is outside the nacelle, lowering the lifting frame along with the wind turbine component and the yoke using the first lifting device to move the yoke along the track until the yoke disengages from the track and becomes supported on the load guide, lowering the load guide and the lifting frame with the wind turbine component supported thereon away from the nacelle, and dismounting the yoke from the load guide. In some embodiments, the lifting frame is attached to the yoke inside the nacelle.

[0032] Further features will be described or will become apparent in the course of the following detailed description. It should be understood that each feature described herein may be utilized in any combination with any one or more of the other described features, and that each feature does not necessarily rely on the presence of another feature except where evident to one of skill in the art.

[0033] Brief Description of the Drawings

[0034] For clearer understanding, preferred embodiments will now be described in detail by way of example, with reference to the accompanying drawings, in which:

[0035] Fig. 1 A depicts a wind turbine with a lifting system comprising a nacelle-mounted lifting device for lifting a load, the wind turbine mounted on a first pillar, the wind turbine having a load guide mounted thereon and lifting lines connecting the load guide to two control devices (e.g., winches) mounted atop respective second and third pillars, the first, second and third pillars connected by gangways.

[0036] Fig. 1 B depicts a wind turbine with a lifting system comprising a nacelle-mounted lifting device for lifting a load, the wind turbine mounted on a common base structure, the wind turbine having a load guide mounted thereon and lifting lines connecting the load guide to two control devices (e.g., winches) mounted on the common base structure.

[0037] Fig. 1 C depicts a wind turbine with a lifting system comprising a nacelle-mounted lifting device for lifting a load, the wind turbine mounted on the ground, the wind turbine having a load guide mounted thereon and lifting lines connecting the load guide to two control devices (e.g., winches) mounted on the ground or on a fixed structure near the wind turbine.

[0038] Fig. 1 D depicts a load guide comprising a circular load control ring disposed around a tower of a wind turbine.

[0039] Fig. 1 E depicts a load guide comprising a hexagonal load control ring disposed around a tower of a wind turbine.

[0040] Fig. 1 F depicts a load guide comprising a square load control ring disposed around a tower of a wind turbine. Fig. 2A depicts a perspective view of a load guide of a lifting system, the load guide disposed around a perimeter of a tower of a wind turbine, the load guide having a lifting frame of the lifting system connected thereto, the lifting frame connected to a nacelle-mounted lifting device of the lifting system through a first lifting line.

[0041] Fig. 2B depicts the load guide of Fig. 2A with a gearbox supported as a load in the lifting frame.

[0042] Fig. 2C depicts a side view of Fig. 2A.

[0043] Fig. 2D depicts a side view of Fig. 2B.

[0044] Fig. 2E depicts a yoke for the lifting system depicted in Fig. 2A.

[0045] Fig. 3A depicts a load control ring of a load guide with an openable / closeable side opened to permit installation of the load control ring around a tower of a wind turbine.

[0046] Fig. 3B depicts the load control ring of Fig. 3A in a process of being closed.

[0047] Fig. 3C depicts the load control ring of Fig. 3A closed around the tower.

[0048] Fig. 3D depicts a side view of the load control ring of Fig. 3C.

[0049] Fig. 3E depicts the load control ring of Fig. 3A raised partially up the towerto a position where the load guide will be connected to a load.

[0050] Fig. 4 depicts a perspective view of the load guide of Fig. 3E with a lifting frame connected thereto, the lifting frame supporting a gearbox of the wind turbine.

[0051] Fig. 5 depicts a side view of Fig. 4.

[0052] Fig. 6 depicts a side of the load guide with the lifting frame and the gearbox lifted up to a nacelle of the wind turbine.

[0053] Fig. 7 depicts a zoomed-out view of Fig. 6 showing a lifting device atop the wind turbine connected to the lifting frame and showing a vertical guide frame outside a side wall of the nacelle extending between an upper edge of the side wall and a bottom of the nacelle where the lifting frame with the gearbox therein is connected to the load guide.

[0054] Fig. 8 depicts a perspective view of Fig. 7. Fig. 9 depicts connection of the lifting frame as shown in Fig. 8 having been transferred from the load guide to a bottom the vertical guide frame.

[0055] Fig. 10 depicts the lifting frame as shown in Fig. 9 having been raised to a top of the vertical guide frame.

[0056] Fig. 11A and Fig. 11 B depict alternate perspective views of Fig. 10.

[0057] Fig. 12 depicts the lifting frame as shown in Fig. 10 having been moved to a centerline of the nacelle over a position where the gearbox is to be installed in the wind turbine.

[0058] Detailed Description

[0059] Fig. 1A, Fig. 1 B and Fig. 1 C depict alternate configurations of a lifting system 10 for lifting (i.e., any combination of raising, lowering and translating horizontally) wind turbine components. In the illustrated configurations, the lifting system 10 comprises an up-tower lifting device 11 (e.g., one or more cranes, winches and the like) mounted atop a tower 2 in a nacelle 3 of a wind turbine 1 and connected to a load 5 by a load lifting line 12 of the lifting system 10. Operation of the up-tower lifting device 11 raises and lowers the load 5 alongside the tower 2. In the illustrated embodiments, the up-tower lifting device 11 comprises a nacellemounted crane. The load 5 may comprise a wind turbine component 6 (see Fig. 1 D to Fig. 1 F), especially a component from inside the nacelle 3, such as a gearbox, a generator, or the like. The load 5 may further comprise a lifting frame 7 for supporting the wind turbine component 6 during lifting. When a lifting frame 7 is utilized, the load lifting line 12 is preferably connected to the lifting frame 7 with the wind turbine component 6 supported in the lifting frame 7.

[0060] The lifting system 10 also comprises a load guide 20 comprising a rigid ring 21 (aka, a load control ring) that extends at least partially around a perimeter of the tower 2, preferably around an entirety of the perimeter, with enough tolerance between the ring 21 and the tower 2 so that the ring 21 can translate vertically through a desired distance along the tower 2 without the ring 21 touching the tower 2. The load guide 20 comprises a plurality of rollers 25 mounted on the ring 21 (see Fig. 1 D to Fig. 1 F). The plurality of rollers 25 is in rolling contact with the tower 2 and roll on the tower 2 as the load guide 20 moves vertically along the tower 2. The plurality of rollers 25 may comprise 2, 3, 4, 5, 6 or more rollers. The number of rollers required or desired depends to some extent on the shape of the ring 21. The plurality of rollers 25 is oriented inwardly from the ring 21 toward the tower 2 to facilitate contact with the tower 2. One or more of the plurality of rollers 25 may be resiliently mounted on the ring 21 to provide a cushioning effect between the rollers 25 and the tower 2. Resilient mounting may be accomplished with springs (e.g., mechanical, pneumatic and the like), for example pneumatic cylinders, compression springs, leaf springs and the like.

[0061] The lifting system 10 also comprises a load guide lifting line 22 that connects the ring 21 to a load guide lifting device 23, which in the illustrated embodiments comprises a downtower winch. The load guide lifting device may comprise one or more lifting devices of the same or different types, for example winches, cranes and the like, and may be situated in any convenient location relative to the ring 21 . In the illustrated embodiments, the load guide lifting line 22 extends from the load guide lifting device 23, located down-tower, up to an anchor arm 24 mounted in the nacelle 3 (see Fig. 11 B), and from the anchor arm 24 down to the ring 21 of the load guide 20. The anchor arm 24 comprises a sheave 26 (see Fig. 11 B) around which the load guide lifting line 22 is reeved. Operation of the load guide lifting device 23 raises and lowers the ring 21 alongside the tower 2. Matching lifting speeds of the up-tower lifting device 11 and the load guide lifting device 23 ensures that the load 5 and the ring 21 are lifted in tandem while the load 5 is being lifted. The lifting system 10 also comprises one or more control devices 27 (e.g., winches, cranes and the like) connected to one or more connecting lines 28 that facilitate connection of the load 5 to the ring 21. The control devices 27 operate to maintain tension on the connecting lines 28 while the load 5 and the ring 21 are being lifted, thereby stabilizing the load 5 against the ring 21 , and, if desired or required, stabilizing the ring 21 against the tower 2. In the illustrated embodiments, the two control devices 27 (individually 27a and 27b) are winches situated down-tower and the connecting lines 28 (individually 28a and 28b) extend upward from the control devices 27 to a rear of the ring 21 where the connecting lines 28 are reeved through sheaves 36 and line guides 37 (see Fig. 4 and Fig. 5) on the ring 21 and then pass along the ring 21 to a front of the ring 21 to the load 5 where the connecting lines 28 are connected to the load 5. In the illustrated embodiments, the connecting lines 28 are connected to the lifting frame 7 of the load 5, thereby connecting the load 5 to the ring 21 . In the illustrated embodiments, the sheaves 36 through which the connecting lines 28 are reeved are situated on the ring 21 at an opposite side of the tower 2 from the load guide lifting line 22 to ensure that the rollers 25 at the opposite side of the tower 2 remain in contact with the tower 2 during a lifting process.

[0062] The alternate configurations of the lifting system 10 shown in Fig. 1A, Fig. 1 B and Fig. 1 C differ in the way the tower 2 is supported and the locations of the control devices 27. In Fig. 1A, the tower 2 is supported atop a first pillar 31 of a triangular offshore wind turbine platform 30 while the control devices 27a and 27b are situated atop respective second pillars 32a and 32b at a same height as a base of the tower 2. The pillars 31 , 32a and 32b are connected by gangways 33 forming the wind turbine platform 30. The load guide lifting device 23 is located on the first pillar 31 at the base of the tower 2. In Fig. 1 B, the tower 2 is supported on a common base structure 34 along with the load guide lifting device 23 and the control devices 27a and 27b. The control devices 27a and 27b are separated from each other on the same side of the base 34 with the tower 2 located on an opposite side from the control devices 27a and 27b on a line perpendicular to and about midway between a line between the control devices 27a and 27b. The tower 2 and the control devices 27a and 27b form a triangular configuration. The load guide lifting device 23 is located on the common base structure 34 at the base of the tower 2. In Fig. 1 C, the tower 2 is supported on the ground along with the load guide lifting device 23 and the control devices 27a and 27b. The load guide lifting device 23 is located on the ground at the base of the tower 2. The control devices 27a and 27b are separated from each other on the same side of the tower 2 but farther away from the tower 2 as the load guide lifting device 23. The tower 2 and the control devices 27a and 27b form a triangular configuration though the connecting lines 28 in Fig. 1C are parallel to each other as the connecting lines 28 extend from the control devices 27a and 27b to the ring 21. In Fig. 1A and Fig. 1 B, the connecting lines 28 are not parallel to each other but converge toward each other as the connecting lines 28 extend from the control devices 27a and 27b to the ring 21.

[0063] The ring 21 can have any suitable shape (e.g., a circle, an oval, a polygon (regular or irregular), or a shape with a combination of straight and curved edges) that permits the ring 21 to extend around the perimeter of the tower 2. Some examples of polygons are triangles, squares, rectangles, pentagons, hexagons and the like. Fig. 1 D, Fig. 1 E and Fig. 1 F illustrate a variety of rings 21a, 21b and 21c. In Fig. 1 D, the ring 21a is circular. In Fig. 1 E, the ring 21b is hexagonal. In Fig. 1 F, the ring 21c is square. Whateverthe shape of the ring 21 , the plurality of rollers 25 is distributed around the ring 21 to ensure that the ring 21 does not contact the tower 2 during a lifting operation. For example, as illustrated in the embodiments of Fig. 1 D, Fig. 1 E and Fig. 1 F, the plurality of rollers 25 comprises one or more rollers at the side of the ring 21 where the load 5 is located and one or more rollers at the opposite side of the ring 21 from where the load 5 is located.

[0064] Fig. 2A to Fig. 2D provide enlarged views of the ring 21 shown in Fig. 1 E disposed around the tower 2. The ring 21 comprises four rollers 25 in contact with the tower 2, two rollers 25 at the same side of the tower 2 as the load 5 and two rollers 25 at the opposite side of the tower 2 from the load 5. The load 5 comprising the lifting frame 7 is connected to the up-tower lifting device through the load lifting line 12 connected to the lifting frame 7. The lifting frame 7 is connected to the ring 21 through a yoke 40 connected to the connecting lines 28. The ring 21 comprises a lug 29 connected to the load guide lifting device 23 through the load guide lifting line 22. Fig. 2A and Fig. 2C show the lifting frame 7 without the wind turbine component, while Fig. 2B and Fig. 2D show the lifting frame 7 with the wind turbine component 6 (i.e., a gearbox) supported therein. As seen in Fig. 2A to Fig. 2D, the lifting system further comprises the yoke 40 rigidly but removably secured to the lifting frame 7. The yoke 40 is configured to be connected to the connecting lines 28 thereby connecting the lifting frame 7, and the wind turbine component 6 supported therein, to the connecting lines 28. As best seen in Fig. 2E, the yoke 40 comprises two parallel multi-armed support elements 41 connected by a crossbar 42. Each support element 41 comprises a central bar 43 and three end arms 44 at a distal end of the central bar 43, the end arms 44 pointing toward the tower 2 when the yoke 40 is in use. The central bar 43 is releasably secured to the lifting frame 7 proximate a proximal end 47 of the central bar 43. The three end arms 44 comprise a first end arm 44a parallel to the central bar 43 and two obliquely oriented end arms 44b, 44c, the two obliquely oriented end arms 44b, 44c forming an angle between each other defining a space in which the first end arm 44a extends. The obliquely oriented end arm 44b is an upper end arm and the obliquely oriented end arm 44c is a lower end arm. The first end arm 44a is a middle end arm and comprises a connector 45 to which one of the connecting lines 28 and / or the ring 21 can be connected. The obliquely oriented end arms 44b, 44c each comprise a rolling element 46, which engage in tracks 51 of a vertical guide fame 50 when the load 5 reaches the top of the tower 2, as described more fully below. The connecting lines 28 run from the control devices 27 to the yoke 40 through sheaves 36 on the ring 21 located on the opposite side of the tower 2 from the load 5, thereby connecting the connecting lines 28 to the lifting frame 7 through the first end arms 44a of the yoke 40. The connecting lines are operated by the control devices 27 to adjust the lateral position of the lifting frame 7 and / or the yoke 40 relative to a vertical axis of the tower 2 to prevent swaying of the load 5 during the lifting process. In some embodiments, the first end arms of the support elements may comprise flanges that are configured to engage with receiving brackets of the ring so that the yoke is further supported on the ring.

[0065] Fig. 3A to Fig. 12 depicts a method of using the lifting system 10 for lifting the wind turbine component 6 along the outside of the tower 2 of the wind turbine 1 .

[0066] As seen in Fig. 3A to Fig. 3C, the ring 21 of the load guide 20 is first installed entirely around the tower 2 with the ring 21 connected to the load guide lifting line 22. To install the ring 21 entirely around the tower 2, the ring 21 is provided with a ring segment 21a, which is openable to permit installing the ring 21 around the tower 2 proximate the base of the tower 2. The ring segment 21a is hinged at one end so that the ring segment 21a can be rotatably connected to the remainder of the ring 21 , whereby rotation of the ring segment 21a at the hinge opens and closes the ring 21. Other ways of making the ring openable to permit installing the ring around the tower may be utilized. As seen in Fig. 2B, once the ring 2 is installed around the tower 2, the ring segment 21a is rotated to a closed position, and the other end of the ring segment 21a is connected to the remainder of the ring 21 to securely close the loop, as seen in Fig. 3C. The ring 21 is initially supported in a horizontal orientation on support columns 8 (only one of four labeled) to provide more support for the ring 21 while the ring 21 is being installed around the tower 2. With the ring 21 secured around the tower 2, the ring 21 is raised off the support columns 8 by the load guide lifting line 22 through operation of the load guide lifting device 23, as seen in Fig. 3D to Fig. 3C.

[0067] In the horizontal orientation, there is a gap between the inwardly oriented rollers 25 and the tower 2 to provide sufficient tolerance for the installation of the ring 21 around the tower 2. As the ring 21 is raised (see Fig. 3D to Fig. 3E), the front of the ring 21 , where the load guide lifting line 22 is connected to the ring 21 , is raised causing the ring 21 to tilt under the influence of gravity so that the rear of the ring 21 is lower than the front of the ring 21. Tilting of the ring 21 brings the rollers 25 into contact with the tower 2 (both at the rear and the front of the ring 21) so that the ring 21 does not bind on the tower 2 during lifting. Furthermore, because a diameter of the tower 2 changes as a function of height along the tower 2, the ability forthe ring 21 to continue tilt underthe influence of gravity as the ring 21 travels (up and down) along the tower 2 helps ensure that the rollers 25 are always in contact with the tower 2 during the lifting process.

[0068] As seen in Fig. 4 and Fig. 5, with the ring 21 raised off the support columns, the control lines 28 (individually 28a, 28b) are installed on the ring 21 , the load 5 with the yoke 40 secured to the lifting frame 7 is brought by the load lifting line 12 into proximity of the load guide 20, and the control lines 28 are connected to the yoke 40.

[0069] As seen in Fig. 6, with the yoke 40 connected to the control lines 28, the up-tower lifting device 11 and the load guide lifting device 23 are operated so that the load lifting line 12 and the load guide lifting line 22 raise the load 5 and the load guide 20, respectively, at a same speed while all the inwardly oriented rollers 25 remain in contact with the tower 2. As can be seen comparing Fig. 6 to Fig. 5, once the load guide 20 reaches the nacelle 3 at the top of the tower 2, the ring 21 is even more tilted because the top of the tower 2 has a smaller diameter than the base of the tower 2. During lifting, one or more of the rollers 25 might lose contact with the tower 2. While gravity is generally sufficient to keep the rollers 25 in contact with the tower 2, in response to one or more of the rollers 25 losing contact with the tower 2 as the load 5 (with the wind turbine component 6) and the load guide 20 move vertically along the tower 2, further tilting the ring 21 to maintain contact of all the rollers 25 with the tower 2 may be accomplished by using the load guide lifting device 23 connected by the load guide lifting line 22 at the front of the load guide 20 to change the speed of the load guide 20 and / or by operating the control devices 27 thereby operating the connecting lines 28 reeved at the rear of the load guide 20 to adjust the lateral position of the front of the ring 21 relative to the vertical axis of the tower 2, thereby adjusting the tilt of the ring 21 .

[0070] As seen in Fig. 6 to Fig. 9, when the load guide 20 and the load 5 reach a bottom of the nacelle 3, the yoke 40 engages a vertical guide frame 50 supported over an upper edge of the nacelle 3. The vertical guide frame 50 extends downward from the upper edge of the nacelle 3 along an outside of the nacelle 3. The vertical guide frame 50 comprises spacedapart arcuate rails 51 that hook over the upper edge of the nacelle 3. The arcuate rails 51 comprise tracks 52 for engaging the rolling elements 46 of the yoke 40, the rolling elements 46 rolling in the tracks 52 when the yoke 40 is engaged with the vertical guide frame 50. The tracks 52 are situated in outer faces of arcuate rails 51 and continue through the vertical and non-vertical portions of the arcuate rails 51. Once the rolling elements 46 of the yoke 40 are engaged on the tracks 52 of the vertical guide frame 50, the load guide lifting device 23 is switched off and the yoke 40 disconnects from the connecting lines 28 and the ring 21 as the load 5 is raised further by the up-tower lifting device 11 . As the load 5 is raised alongside the nacelle 3, the rolling elements 46 roll in the tracks 52, the tracks 52 keeping the load 5 moving in a straight line until the yoke 40 and the load 5 reach a top of the vertical guide frame 50 and are higher than an upper edge of the nacelle 3.

[0071] As seen in Fig. 10 to Fig. 11 B, when the yoke 40 reaches the top of the vertical guide frame 50, the arcuate rails 51 bend from first vertically oriented portions 51a into horizontally oriented portions 51 b so that the tracks 52 are also horizontally oriented toward an inside of the nacelle 3. As the up-tower lifting device 11 moves the load 5 horizontally toward the inside of the nacelle 3, the rolling elements 46 of the upper obliquely oriented end arms 44b of the yoke 40 roll in the horizontally oriented portions 51 b causing the yoke 40 to start pivoting relative to the lifting frame 7 so that the lifting frame 7 and the wind turbine component 6 therein are raised over the yoke 40. Continuing the horizontal motion, the arcuate rails 51 inside the nacelle 3 bend downward into second vertically oriented portions 51c so that the tracks 52 are vertically oriented as well. The rolling elements 46 of the upper obliquely oriented end arms 44b roll downward in the second vertically oriented portions 51c inside the nacelle 3 and the lower obliquely oriented end arms 44c trailing behind the upper obliquely oriented end arms 44b roll into the horizontally oriented portions 51 b. Thus, the yoke 40 essentially flips over as the yoke 40 follows the tracks 52 over and into the nacelle 3.

[0072] The above-described motion of the yoke 40 on the vertical guide frame 50 causes the yoke 40 to be released from the lifting frame 7 so that the lifting frame 7 is independent of the yoke 40, as shown in Fig. 12. In addition, the yoke 40 is supported on the nacelle 3 by the vertical guide frame 50 awaiting use in a return journey down the tower 2. The lifting frame 7 is positioned over top the destination for the wind turbine component 6 and lowered to place the wind turbine component 6 in position. The lifting frame 7 is detached from the wind turbine component 6.

[0073] Reversing the process permits lowering a load from the nacelle 3 down to the base of the tower 2.

[0074] The novel features will become apparent to those of skill in the art upon examination of the description. It should be understood, however, that the scope of the claims should not be limited by the embodiments but should be given the broadest interpretation consistent with the wording of the claims and the specification as a whole.

Claims

Claims:1 . A lifting system for lifting a wind turbine component of a wind turbine, the lifting system comprising: a first lifting device situated in a nacelle of the wind turbine, the first lifting device connectable by a first lifting line to the wind turbine component for raising and lowering the wind turbine component; a second lifting device; and, a load guide connected to the second lifting device by a second lifting line to be raisable and lowerable by the second lifting device, the load guide comprising: a rigid ring that extends at least partially around a perimeter of a tower of the wind turbine; a plurality of rollers mounted on the ring, each of the plurality of rollers configured to rollingly contact the tower and roll on the tower as the load guide moves vertically along the tower; and, one or more load connectors configured to receive and support the wind turbine component on the load guide.

2. The lifting system of claim 1 , wherein:(a) a segment of the ring is openable to permit installing the ring around the tower proximate a base of the tower;(b) the plurality of rollers of the load guide comprises at least three rollers spaced around of the ring to prevent the load guide from becoming stuck while the load guide moves vertically along the tower;© the ring is polygonal, preferably four-sided;(d) the second lifting device comprises a lift winch situated on a platform apart from the tower; or,(d) any combination of (a) to (d).

3. The lifting system of claim 1 or claim 2, wherein the one or more load connectors comprises one or more connecting lines, one or more receiving brackets, one or more connecting arms or any combination thereof.

4. The lifting system of any one of claims 1 to 3, wherein:the plurality of rollers of the load guide is oriented inwardly from the ring toward the tower and the ring is connected to the second lifting line at a position on the ring so that lifting the ring causes the ring to tilt thereby engaging all of the rollers of the plurality of rollers of the load guide with the tower.

5. The lifting system of any one of claims 1 to 4, further comprising: a lifting frame configured to be securely attachable to the wind turbine component, the lifting frame connected by the first lifting line to the first lifting device; a yoke secured to the lifting frame, the yoke comprising a plurality of rolling elements, the yoke configured to be received and supported by the one or more load connectors of the load guide; a vertical guide frame supported over an upper edge of the nacelle, the vertical guide frame extending downward from the upper edge of the nacelle along an outside of the nacelle, the vertical guide frame comprising tracks in which the plurality of rolling elements of the yoke rolls when the yoke is engaged with the vertical guide frame; and, connecting lines connected to one or both of the lifting frame and the yoke for adjusting lateral position of the lifting frame and / or the yoke relative to a vertical axis of the tower.

6. The lifting system of claim 5, wherein: the one or more load connectors comprises two spaced-apart receiving brackets oriented outwardly from the ring and positioned so that second lifting line is connected to the load guide at a position between the two receiving brackets; the yoke comprises opposed spaced-apart multi-armed support elements connected by a crossbar, wherein: first ends of the support elements comprising flanges are configured to engage with the receiving brackets of the load guide so that the yoke is supported on the load guide; second ends of the support elements are configured to be rigidly but removably secured to the lifting frame; and, arms of the support elements comprise the rolling elements, the arms oriented so that the rolling elements engage the tracks of the vertical guide fame when the yoke engages the vertical guide frame; and,the vertical guide frame comprises spaced-apart arcuate rails that hook over the upper edge of the nacelle, the arcuate rails comprising the tracks for engaging the rolling elements of the yoke.

7. The lifting system of claim 5 or claim 6, further comprising control winches connected to the connecting lines for operating the connecting lines.

8. The lifting system of any one of claims 1 to 7, further comprising an anchor arm mounted in the nacelle, the anchor arm comprising a sheave around which the second lifting line is reeved, the second lifting line extending from the second lifting device up to the anchor arm and from the anchor arm down to the load guide.

9. The lifting system of any one of claims 1 to 8, wherein the wind turbine component is a gearbox or a generator.

10. A load guide for assisting with lifting and lowering a wind turbine component to and from a nacelle of a wind turbine, the load guide comprising: a rigid ring extendable at least partially around a perimeter of a tower of the wind turbine; a plurality of inwardly oriented rollers mounted on the ring, the rollers spaced-apart around the ring and configured to roll on the tower as the load guide moves vertically along the tower; a lug configured to be connected to a lifting line; and, one or more outwardly oriented load connectors configured to securely attach the wind turbine component thereto, the one or more outwardly-oriented load connectors positioned so that lifting of the load guide causes the ring to tilt thereby causing the plurality of rollers to engage with the tower.11 . The load guide of claim 10, wherein:(a) the load guide further comprises sheaves and line guides configured to guide connecting lines along the ring from a rear to a front of the ring;(b) a segment of the ring is openable to permit installing the ring around the tower proximate a base of the tower;(c) the plurality of inwardly oriented rollers comprises two opposed sets of two rollers;(d) the ring is polygonal; or,(e) any combination of (a) to (d).

12. The load guide of claim 10, wherein: a segment of the ring is openable to permit installing the ring around the tower proximate a base of the tower; the ring is a multi-sided polygon; the plurality of inwardly oriented rollers comprises two sets of two rollers whereby the sets of rollers are on opposed sides of the polygon; the one or more outwardly oriented load connectors comprises two spaced-apart load connectors; the lug is positioned between the two load connectors; and; the load guide further comprises sheaves and line guides configured to guide connecting lines along the ring between from a rear of the ring to the two load connectors at a front of the ring, wherein the two load connectors comprise end portions of two of the guide connecting lines.

13. A method of raising or lowering of a wind turbine component to or from a nacelle of a wind turbine, the method comprising: connecting the wind turbine component to a load guide, the load guide comprising: a rigid ring extending at least partially around a perimeter of a tower of the wind turbine; and, a plurality of inwardly oriented rollers mounted on the ring, the rollers spaced- apart around the ring and configured to roll on the tower as the load guide moves vertically along the tower; raising or lowering the wind turbine component with a first lifting device and raising or lowering the load guide with a second lifting device, whereby the second lifting device is connected to the load guide at a lifting point so that the inwardly oriented rollers are in contact with the tower during the raising or lowering of the load guide and the wind turbine component and the load guide are lifted or lowered at a same speed while all the inwardly oriented rollers are in contact with the tower.

14. The method of claim 13, further comprising:(a) supporting the wind turbine component on a lifting frame for the wind turbine component, attaching a yoke to the lifting frame, supporting the yoke on the load guide,lifting the load guide and the lifting frame with the wind turbine component attached thereto up to the nacelle, detaching the yoke from the load guide by lifting the lifting frame along with the wind turbine component and the yoke away from the load guide using the first lifting device, engaging the yoke with a track on an arcuate rail hooked over an upper edge of the nacelle, lifting the lifting frame along with the wind turbine component and the yoke using the first lifting device to move the yoke along the track over top of the upper edge of the nacelle until the wind turbine component is inside the nacelle, lowering the lifting frame along with the wind turbine component into the nacelle using the first lifting device, and removing the wind turbine component from the lifting frame; or,(b) supporting the wind turbine component on a lifting frame for the wind turbine component inside the nacelle of the wind turbine, lifting the lifting frame along with the wind turbine component using the first lifting device, lifting the lifting frame along with the wind turbine component and a yoke attached to the lifting frame using the first lifting device to move the yoke along a track of an arcuate rail hooked over an upper edge of the nacelle such that the lifting frame with the wind turbine component therein and the yoke are lifted over top of the upper edge of the nacelle until the wind turbine component is outside the nacelle, lowering the lifting frame along with the wind turbine component and the yoke using the first lifting device to move the yoke along the track until the yoke disengages from the track and becomes supported on the load guide, lowering the load guide and the lifting frame with the wind turbine component supported thereon away from the nacelle, and dismounting the yoke from the load guide.

15. The method of claim 14 or claim 15 comprising using the lifting system of any one of claims 1 to 9.

16. The method of any one of claims 13 to 15, wherein the load guide is the load guide of any one of claims 10 to 12.

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